21 CFR 640.22 - Collection of source material.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) BIOLOGICS ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Platelets § 640.22 Collection of source material. (a) Whole blood used as the source of Platelets shall be collected as prescribed in § 640.4. (b... uninterrupted venipuncture with minimal damage to, and minimal manipulation of, the donor's tissue. [40 FR 4304...

Optical feedback-induced light modulation for fiber-based laser ablation.

PubMed

Kang, Hyun Wook

2014-11-01

Optical fibers have been used as a minimally invasive tool in various medical fields. However, due to excessive heat accumulation, the distal end of a fiber often suffers from severe melting or devitrification, leading to the eventual fiber failure during laser treatment. In order to minimize thermal damage at the fiber tip, an optical feedback sensor was developed and tested ex vivo. Porcine kidney tissue was used to evaluate the feasibility of optical feedback in terms of signal activation, ablation performance, and light transmission. Testing various signal thresholds demonstrated that 3 V was relatively appropriate to trigger the feedback sensor and to prevent the fiber deterioration during kidney tissue ablation. Based upon the development of temporal signal signatures, full contact mode rapidly activated the optical feedback sensor possibly due to heat accumulation. Modulated light delivery induced by optical feedback diminished ablation efficiency by 30% in comparison with no feedback case. However, long-term transmission results validated that laser ablation assisted with optical feedback was able to almost consistently sustain light delivery to the tissue as well as ablation efficiency. Therefore, an optical feedback sensor can be a feasible tool to protect optical fiber tips by minimizing debris contamination and delaying thermal damage process and to ensure more efficient and safer laser-induced tissue ablation.

Glomerular Diseases

MedlinePlus

... dialysis or transplantation to replace renal function. Bacterial endocarditis, infection of the tissues inside the heart, is ... the most effective way of minimizing kidney damage. Endocarditis sometimes produces chronic kidney disease (CKD) . HIV, the ...

Ultrasound-induced cavitation damage to external epithelia of fish skin.

PubMed

Frenkel, V; Kimmel, E; Iger, Y

1999-10-01

Transmission electron microscopy was used to show the effects of therapeutic ultrasound (< or = 1.0 W/cm2, 1 MHz) on the external epithelia of fish skin. Exposures of up to 90 s produced damage to 5 to 6 of the outermost layers. Negligible temperature elevations and lack of damage observed when using degassed water indicated that the effects were due to cavitation. The minimal intensity was determined for inducing cellular damage, where the extent and depth of damage to the tissues was correlated to the exposure duration. The results may be interpreted as a damage front, advancing slowly from the outer cells inward, presumably in association with the slow replacement of the perforated cell contents with the surrounding water. This study illustrates that a controlled level of microdamage may be induced to the outer layers of the tissues.

Towards a minimally invasive sampling tool for high resolution tissue analytical mapping

NASA Astrophysics Data System (ADS)

Gottardi, R.

2015-09-01

Multiple spatial mapping techniques of biological tissues have been proposed over the years, but all present limitations either in terms of resolution, analytical capacity or invasiveness. Ren et al (2015 Nanotechnology 26 284001) propose in their most recent work the use of a picosecond infrared laser (PIRL) under conditions of ultrafast desorption by impulsive vibrational excitation (DIVE) to extract small amounts of cellular and molecular components, conserving their viability, structure and activity. The PIRL DIVE technique would then work as a nanobiopsy with minimal damage to the surrounding tissues, which could potentially be applied for high resolution local structural characterization of tissues in health and disease with the spatial limit determined by the laser focus.

Precision resection of lung cancer in a sheep model using ultrashort laser pulses

NASA Astrophysics Data System (ADS)

Beck, Rainer J.; Mohanan, Syam Mohan P. C.; Góra, Wojciech S.; Cousens, Chris; Finlayson, Jeanie; Dagleish, Mark P.; Griffiths, David J.; Shephard, Jonathan D.

2017-02-01

Recent developments and progress in the delivery of high average power ultrafast laser pulses enable a range of novel minimally invasive surgical procedures. Lung cancer is the leading cause of cancer deaths worldwide and here the resection of lung tumours by means of picosecond laser pulses is presented. This represents a potential alternative to mitigate limitations of existing surgical treatments in terms of precision and collateral thermal damage to the healthy tissue. Robust process parameters for the laser resection are demonstrated using ovine pulmonary adenocarcinoma (OPA). OPA is a naturally occurring lung cancer of sheep caused by retrovirus infection that has several features in common with some forms of human pulmonary adenocarcinoma, including a similar histological appearance, which makes it ideally suited for this study. The picosecond laser was operated at a wavelength of 515 nm to resect square cavities from fresh ex-vivo OPA samples using a range of scanning strategies. Process parameters are presented for efficient ablation of the tumour with clear margins and only minimal collateral damage to the surrounding tissue. The resection depth can be controlled precisely by means of the pulse energy. By adjusting the overlap between successive laser pulses, deliberate heat transfer to the tissue and thermal damage can be achieved. This can be beneficial for on demand haemostasis and laser coagulation. Overall, the application of ultrafast lasers for the resection of lung tumours has potential to enable significantly improved precision and reduced thermal damage to the surrounding tissue compared to conventional techniques.

Internalization of fresh produce by foodborne pathogens.

PubMed

Erickson, Marilyn C

2012-01-01

Recent studies addressing the internalization of fresh produce by foodborne pathogens arose in response to the growing number of recent and high profile outbreaks involving fresh produce. Because chemical sanitizing agents used during harvest and minimal processing are unlikely to reach enteric pathogens residing within plant tissue, it is imperative that paths for pathogen entry be recognized and minimized. Using both microscopy and microbial enumeration tools, enteric pathogens have been shown to enter plant tissues through both natural apertures (stomata, lateral junctions of roots, flowers) and damaged (wounds, cut surfaces) tissue. In studies revealing preharvest internalization via plant roots or leaf stomata, experimental conditions have primarily involved exposure of plants to high pathogen concentrations (≥ 6 log g⁻¹ soil or 6 log ml⁻¹ water), but those pathogens internalized appear to have short-term persistence. Postharvest internalization of pathogens via cut surfaces may be minimized by maintaining effective levels of sanitizing agents in waters during harvesting and minimal processing.

[Precise application of Traditional Chinese Medicine in minimally-invasive techniques].

PubMed

Dong, Fu-Hui

2018-06-25

The miminally-invasive techniques of traditional Chinese medicine(TCM) uses different types of acupuncture needles to treat diseased locations with special techniques. These techniques include different methods of insertion and closed incision (press cutting, sliding cutting, scrape cutting, etc.). This needling technique is based on the traditional Chinese medicine theories of Pi Bu (cutaneous), Jing Jin (sinew), Jing Luo (meridian), Wu Ti (five body structure components) and Zang Fu (organ system). Commonly used needles include: needle Dao , needle with edge, Pi needle, Shui needle, Ren needle, Gou needle, Chang Yuan needle, Bo needle and so on. The principle of this minimally-invasive technique of TCM is to achieve the greatest healing benefit with the least amount of anatomical and physiological intervention. This will result in the highest standard of health care with the lowest rehabilitative need and burden of care. In the past 20 years, through the collaborative research of several hundred hospitals across China, we systemically reviewed the best minimally invasive technique of TCM and the first line treatments for selective conditions. In 2013, the Department of Medical Affairs of the State Administration of Traditional Chinese Medicine created "Traditional Chinese Medicine Technical Manual"(General Version) and released it nationwide, its contents include: (1)Minimally invasive scar tissue release. ¹Suitable for Bi and pain syndromes of neck, shoulder, waist, buttocks and extremities. ²Degeneration causes local hypertrophy and inflammation, creating local tissue adhesion. ³There are two kind incision methods-press cutting and slide cutting. (2)Minimally invasive fascial tension release. ¹Suitable for localized fascial tension caused by trauma, overuse, or wind-cold-dampness, leading to compensatory hyperplasia. ²Long term high-stress stimulation to local fascia creates compensatory hyperplasia, Ashi points, and tissue texture changes (cords, nodules, masses). ³According to the different structural features of the needles, there are two incision methods: penetrating from the outside to the inside and pulling from inside to outside. (3)Minimally invasive decompression technique. ¹Suitable for internal pressure changes within organ cavities caused by trauma, degeneration, inflammation, such as compartment syndrome, bone marrow edema, increased intraluminal pressure in the bone marrow. ²According to the different tissues, it is categorized into soft tissue decompression, and bone decompression. (4)Minimally invasive orthopedic surgery. Applicable to some postural, developmental deformity correction, mainly through the dynamic balance method and/or static balance method. (5)Minimally invasive dissection. Suitable for fractures, tendons injury caused by deep soft tissue adhesion. (6)Minimally invasive separation. ¹Suitable for cutaneous, sinew regions, superficial adhesions due to lesions, and local post-operative incision adhesions. ²According to the structure of the needle tip, the methods are divided into sharp separation and blunt dissection. (7)Minimally invasive sustained pressure technique. ¹Suitable for neuromuscular dysfunction which causes JING (spasm) syndrome and WEI (atrophy) syndrome. ²The needle is applied with sustained pressure, without penetrating select tissue surface. This includes: nerve root sustained pressure technique; peripheral nerve sustained pressure technique; muscle sustained pressure technique; fascial contact procedure; cutaneous sustained pressure technique.(8)Minimally invasive insertion technique. ¹Suitable for systemic regulation to treat disease. ²Different organs are connected to different layers of tissue. Therefore, to treat specific conditions, specific tissues must be targeted. ³For example, back Shu points are used to treat vertigo from cervical spine issues, and spinal degeneration associated digestion issue. ⁴The internal organs can be regulated by the pathways that runs along the different layers of tissue. The types of stimulation include: meridian acupoint stimulation; cutaneous stimulation; fascia stimulation; mucle stimulation; periosteum stimulation. The clinical application of these techniques has enriched the drug-free therapies of traditional Chinese medicine and achieved excellent outcomes, but at the same time it also raises an important question. How can we apply these minimally invasive techniques to clinical practice so it can be safe and effective? In addition, how can practitioners, individually and further develop their understanding of this minimally invasive technique progressive manner? We make the following recommendations. (1)Clear diagnosis and precise application. Any approach has specific indications and choosing the correct technique comes from a comprehensive understanding of its advantages and disadvantages. Moreover, the accurate application of the technique depends the expertise of the practitioner. Through systematic review and clinical observation, we formulated the First Line Treatment, the Second Line Treatment, and the Third Line Treatment for specific conditions. Using the information gathered from research, practitioners can decide on which point is appropriate to use based on the stage of disease progression. For example, common conditions like the nerve ending tension pain(i.e. cutaneous nerve entrapment syndrome) is caused by stress concentration. There are two types of treatment for this condition: ¹Change in the response to stress state (i.e.non-invasive approach such as manual therapy and physiotherapy). ²Change in state of surrounding environment (i.e. invasive approach such as Pi Needle). Before tissue texture changes to pain point, cord, nodules, the former approach is effective. Once tissue texture changes, the latter approach is First Line Treatment. (2)Systematic training and disease progression training. The minimally invasive techniques of traditional Chinese medicine can treat many kinds of disease. To ensure its safety, organization, progressive development, practitioners are trained systematically and manage their treatment approach through disease hierarchy. Moreover, this technique should be conducted according to its technical difficulty, operating conditions, and expertise of the practitioner. The application of minimally invasive techniques of traditional Chinese medicine does not depend on the hospitals' administration system or the regulatory college of medical professionals. The minimally invasive techniques of TCM should be taught from easy to difficult, simple to complicated, and requires gradual progression by the practitioners. Eventually, the minimally invasive techniques of TCM's diagnostic and treatment protocol can be created. These protocols are currently available for reference: ¹Forming diagnosis and differential diagnosis for the conditions below requires expert diagnostic and application skills: cerebral palsy; cervical vertigo; cervical headache; cervical precordial pain; other spine-related diseases. ²The requirements for the diagnosis and differential diagnosis of such techniques are relatively high, and special training is required for the practitioner who performs this technique. The conditions below uses minimally invasive orthopedic surgery and dissection: scar contracture deformity; congenital developmental malformations; cervical Bi -syndrome; shoulder pain syndrome; knee Bi -syndrome; low back pain; cervical spondylosis; lumbar disc herniation; avascular necrosis of the femoral head; ankylosing spondylitis. ³There are no special requirements for the diagnosis and differential diagnosis of such techniques, and special training is required for the practitioner who performs this technique. The technical content is mainly decompression and scar tissue release. a)Muscle strain diseases: levator scapulae, splenius capitis, splenius cervicis, supraspinatus, infraspinatus, teres minor, teres major, serratus posterior superior, serratus posterior inferior, piriformis, gluteus maximus, gluteus medius, and gluteus minimus, erector spinae. b)Joint degenerative disorders: frozen shoulder, tennis elbow, tenosynovitis, knee osteoarthritis, and plantar fascitis. c) JING-JIN PI-BU pain syndrome (cutaneous nerve entrapment syndrome): occipital great nerve entrapment syndrome, occipital small nerve entrapment syndrome, great auricular nerve entrapment syndrome, suprascapular nerve entrapment syndrome, transverse cutaneous nerve of neck entrapment syndrome. (3)People-centred practice. The most attractive feature of the minimally invasive techniques of TCM is that they do not rely on expensive medical equipment and operating conditions. The key to applying this technique is the practitioners' technique, skill, and expertise. The necessary conditions required to successfully apply this technique is ¹practitioner understands disease progression and diagnosis; ²practitioners' skill in applying technique. We require patient-centered approach, which uses evidence based approach as the focus. We aim to seek the truth from facts, to understand the comprehensive picture, to include pertinent details, to be observant, to be goal oriented, from one to another, from outside to inside, from top to the bottom, compare right from left, through active movement and passive movements and weight-bearing movements, and assisted passive movements to determine instantaneous centre to diagnose stress concentration points. The operating technique is based on the response of patient's tissues to this technique. We must pay attention to diagnosis through palpation: layers, structure, texture, deformity, dislocation, movement characteristic, rhythmic changes. To achieve SHOU MO XIN HUI WU WEI : position, quantify, quantity, timing, and pattern. Accurate grasp of timeliness and dose efficiency. Can distinguish between local or systemic effects of treatment. Through comprehensive judgment of hands feeling, acupuncture needle feeling, and inspiration, to achieve the precious treatment requirements as indicated by the "Huangdi Neijing·Suwen" : "Puncture the bone without damaging tendons, and puncture tendons without damaging muscles, puncture the muscle without damaging pulse, puncture pulse without damaging skin, puncture skin without damaging muscle. Puncture muscle without damage tendons, puncture tendons without damaging bone... Puncture bone without damaging tendons and it means the needle passes through the tendons and arrives at the bone and work on the bone. Puncture tendons without damaging muscles, and it means the needle passes through the muscles and arrives close to the tendon. Puncture the muscle without damaging pulse and it means the needle passes the pulse and does not touch the muscle. Puncture pulse without damaging skin and it means, the needle passes through the skin without penetrating pulse. Puncture skin without damaging muscle and it means, the disease is in the skin and the needles insert into skin but does not damage muscle. Puncture muscle without damage tendons, and it means, the needle passes through the muscle and arrive on the tendon. Puncture tendons without damaging bone." Copyright© 2018 by the China Journal of Orthopaedics and Traumatology Press.

Novel management of distal tibial and fibular fractures with Acumed fibular nail and minimally invasive plating osteosynthesis technique: A case report.

PubMed

Wang, Tie-Jun; Ju, Wei-Na; Qi, Bao-Chang

2017-03-01

Anatomical characteristics, such as subcutaneous position and minimal muscle cover, contribute to the complexity of fractures of the distal third of the tibia and fibula. Severe damage to soft tissue and instability ensure high risk of delayed bone union and wound complications such as nonunion, infection, and necrosis. This case report discusses management in a 54-year-old woman who sustained fractures of the distal third of the left tibia and fibula, with damage to overlying soft tissue (swelling and blisters). Plating is accepted as the first choice for this type of fracture as it ensures accurate reduction and rigid fixation, but it increases the risk of complications. Closed fracture of the distal third of the left tibia and fibula (AO: 43-A3). After the swelling was alleviated, the patient underwent closed reduction and fixation with an Acumed fibular nail and minimally invasive plating osteosynthesis (MIPO), ensuring a smaller incision and minimal soft-tissue dissection. At the 1-year follow-up, the patient had recovered well and had regained satisfactory function in the treated limb. The Kofoed score of the left ankle was 95. Based on the experience from this case, the operation can be undertaken safely when the swelling has been alleviated. The minimal invasive technique represents the best approach. Considering the merits and good outcome in this case, we recommend the Acumed fibular nail and MIPO technique for treatment of distal tibial and fibular fractures.

Soft tissue infection after missile injuries to the extremities--a non-randomized, prospective study in Gaza City.

PubMed

Hamouda, Hazem M; Witsø, Eivind; Moghani, Nedal K E; Shahwan, Ahmed; Nygaard, Oystein P

2007-01-01

Patients with soft tissue injuries caused by missile attacks during wartime have been treated with radical debridement and delayed closure. In a study in Gaza City, the rate of infection of missile injuries to the extremities when treated with minimal surgical intervention, was measured. Patients with severe soft tissue damage, compound fractures, and injuries to major blood vessels and/or nerves were excluded from the study. One hundred fourteen patients were treated according to a standardized regime that included a superficial, minor surgery revision of the inlet and the outlet opening, and antibiotic treatment. Local soft tissue infection was defined as the presence of at least two signs of local infection. A total of 109 out of 114 patients attended the first follow-up visit. Eleven (10%) of these patients had an infected wound. A total of 105 of the patients (92%) attended a second follow-up. None of these patients had an infected wound. Under conditions with a high number of casualties, minimal surgical treatment followed by the administration of antibiotics is a safe procedure for patients with penetrating missile injuries and less severe soft tissue damage.

Improving Large Cetacean Implantable Satellite Tag Designs to Maximize Tag Robustness and Minimize Health Effects to Individual Animals

DTIC Science & Technology

2013-09-30

Designs to Maximize Tag Robustness and Minimize Health Effects to Individual Animals Alexandre N. Zerbini Cascadia Research Collective 218 ½ 4th...the blubber-muscle interface and minimize physical and physiological effects of body penetrating tags to individual animals . OBJECTIVES (1...integrity of designs created in Objective (1) during laboratory experiments and in cetacean carcasses ; (3) Examine structural tissue damage in the

Reconstruction of Craniomaxillofacial Bone Defects Using Tissue-Engineering Strategies with Injectable and Non-Injectable Scaffolds

PubMed Central

Gaihre, Bipin; Uswatta, Suren; Jayasuriya, Ambalangodage C.

2017-01-01

Engineering craniofacial bone tissues is challenging due to their complex structures. Current standard autografts and allografts have many drawbacks for craniofacial bone tissue reconstruction; including donor site morbidity and the ability to reinstate the aesthetic characteristics of the host tissue. To overcome these problems; tissue engineering and regenerative medicine strategies have been developed as a potential way to reconstruct damaged bone tissue. Different types of new biomaterials; including natural polymers; synthetic polymers and bioceramics; have emerged to treat these damaged craniofacial bone tissues in the form of injectable and non-injectable scaffolds; which are examined in this review. Injectable scaffolds can be considered a better approach to craniofacial tissue engineering as they can be inserted with minimally invasive surgery; thus protecting the aesthetic characteristics. In this review; we also focus on recent research innovations with different types of stem-cell sources harvested from oral tissue and growth factors used to develop craniofacial bone tissue-engineering strategies. PMID:29156629

Geometric modeling of space-optimal unit-cell-based tissue engineering scaffolds

NASA Astrophysics Data System (ADS)

Rajagopalan, Srinivasan; Lu, Lichun; Yaszemski, Michael J.; Robb, Richard A.

2005-04-01

Tissue engineering involves regenerating damaged or malfunctioning organs using cells, biomolecules, and synthetic or natural scaffolds. Based on their intended roles, scaffolds can be injected as space-fillers or be preformed and implanted to provide mechanical support. Preformed scaffolds are biomimetic "trellis-like" structures which, on implantation and integration, act as tissue/organ surrogates. Customized, computer controlled, and reproducible preformed scaffolds can be fabricated using Computer Aided Design (CAD) techniques and rapid prototyping devices. A curved, monolithic construct with minimal surface area constitutes an efficient substrate geometry that promotes cell attachment, migration and proliferation. However, current CAD approaches do not provide such a biomorphic construct. We address this critical issue by presenting one of the very first physical realizations of minimal surfaces towards the construction of efficient unit-cell based tissue engineering scaffolds. Mask programmability, and optimal packing density of triply periodic minimal surfaces are used to construct the optimal pore geometry. Budgeted polygonization, and progressive minimal surface refinement facilitate the machinability of these surfaces. The efficient stress distributions, as deduced from the Finite Element simulations, favor the use of these scaffolds for orthopedic applications.

Tissue modification with feedback: the smart scalpel

NASA Astrophysics Data System (ADS)

Sebern, Elizabeth L.; Brenan, Colin J. H.; Anderson, R. Rox; Hunter, Ian W.

1998-10-01

While feedback control is widespread throughout many engineering fields, there are almost no examples of surgical instruments that utilize a real-time detection and intervention strategy. This concept of closed loop feedback can be applied to the development of autonomous or semi- autonomous minimally invasive robotic surgical systems for efficient excision or modification of diseased tissue. Spatially localized regions of the tissue are first probed to distinguish pathological from healthy tissue based on differences in histochemical and morphological properties. Energy is directed to only the diseased tissue, minimizing collateral damage by leaving the adjacent healthy tissue intact. Continuous monitoring determines treatment effectiveness and, if needed, enables real-time treatment modifications to produce optimal therapeutic outcomes. The present embodiment of this general concept is a microsurgical instrument we call the Smart Scalpel, designed to treat skin angiodysplasias such as port wine stains. Other potential Smart Scalpel applications include psoriasis treatment and early skin cancer detection and intervention.

Laser ablation of human atherosclerotic plaque without adjacent tissue injury

NASA Technical Reports Server (NTRS)

Grundfest, W. S.; Litvack, F.; Forrester, J. S.; Goldenberg, T.; Swan, H. J. C.

1985-01-01

Seventy samples of human cadaver atherosclerotic aorta were irradiated in vitro using a 308 nm xenon chloride excimer laser. Energy per pulse, pulse duration and frequency were varied. For comparison, 60 segments were also irradiated with an argon ion and an Nd:YAG laser operated in the continuous mode. Tissue was fixed in formalin, sectioned and examined microscopically. The Nd:YAG and argon ion-irradiated tissue exhibited a central crater with irregular edges and concentric zones of thermal and blast injury. In contrast, the excimer laser-irradiated tissue had narrow deep incisions with minimal or no thermal injury. These preliminary experiments indicate that the excimer laser vaporizes tissue in a manner different from that of the continuous wave Nd:YAG or argon ion laser. The sharp incision margins and minimal damage to adjacent normal tissue suggest that the excimer laser is more desirable for general surgical and intravascular uses than are the conventionally used medical lasers.

Checkpoint Inhibitor Sensitizes Human Tumor Cells | Center for Cancer Research

Cancer.gov

One unfortunate and detrimental side effect of ionizing radiation as a treatment for cancer is the damage it imparts to normal tissue near the targeted tumor. Technology has improved radiation delivery, minimizing the volume of normal tissue in the radiation field, but has not eliminated it completely. Thus, the identification of drugs that increase the sensitivity of cancer

Pathologic features of fatal shark attacks.

PubMed

Byard, R W; Gilbert, J D; Brown, K

2000-09-01

To examine the pattern of injuries in cases of fatal shark attack in South Australian waters, the authors examined the files of their institution for all cases of shark attack in which full autopsies had been performed over the past 25 years, from 1974 to 1998. Of the seven deaths attributed to shark attack during this period, full autopsies were performed in only two cases. In the remaining five cases, bodies either had not been found or were incomplete. Case 1 was a 27-year-old male surfer who had been attacked by a shark. At autopsy, the main areas of injury involved the right thigh, which displayed characteristic teeth marks, extensive soft tissue damage, and incision of the femoral artery. There were also incised wounds of the right wrist. Bony injury was minimal, and no shark teeth were recovered. Case 2 was a 26-year-old male diver who had been attacked by a shark. At autopsy, the main areas of injury involved the left thigh and lower leg, which displayed characteristic teeth marks, extensive soft tissue damage, and incised wounds of the femoral artery and vein. There was also soft tissue trauma to the left wrist, with transection of the radial artery and vein. Bony injury was minimal, and no shark teeth were recovered. In both cases, death resulted from exsanguination following a similar pattern of soft tissue and vascular damage to a leg and arm. This type of injury is in keeping with predator attack from underneath or behind, with the most severe injuries involving one leg. Less severe injuries to the arms may have occurred during the ensuing struggle. Reconstruction of the damaged limb in case 2 by sewing together skin, soft tissue, and muscle bundles not only revealed that no soft tissue was missing but also gave a clearer picture of the pattern of teeth marks, direction of the attack, and species of predator.

Fs-laser ablation of teeth is temperature limited and provides information about the ablated components.

PubMed

de Menezes, Rebeca Ferraz; Harvey, Catherine Malinda; de Martínez Gerbi, Marleny Elizabeth Márquez; Smith, Zachary J; Smith, Dan; Ivaldi, Juan C; Phillips, Alton; Chan, James W; Wachsmann-Hogiu, Sebastian

2017-10-01

The goal of this work is to investigate the thermal effects of femtosecond laser (fs-laser) ablation for the removal of carious dental tissue. Additional studies identify different tooth tissues through femtosecond laser induced breakdown spectroscopy (fsLIBS) for the development of a feedback loop that could be utilized during ablation in a clinical setting. Scanning Election Microscope (SEM) images reveal that minimal morphological damages are incurred at repetition rates below the carbonization threshold of each tooth tissue. Thermal studies measure the temperature distribution and temperature decay during laser ablation and after laser cessation, and demonstrate that repetition rates at or below 10kHz with a laser fluence of 40 J/cm 2 would inflict minimal thermal damage on the surrounding nerve tissues and provide acceptable clinical removal rates. Spectral analysis of the different tooth tissues is also conducted and differences between the visible wavelength fsLIBS spectra are evident, though more robust classification studies are needed for clinical translation. These results have initiated a set of precautionary recommendations that would enable the clinician to utilize femtosecond laser ablation for the removal of carious lesions while ensuring that the solidity and utility of the tooth remain intact. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Precision machining of pig intestine using ultrafast laser pulses

NASA Astrophysics Data System (ADS)

Beck, Rainer J.; Góra, Wojciech S.; Carter, Richard M.; Gunadi, Sonny; Jayne, David; Hand, Duncan P.; Shephard, Jonathan D.

2015-07-01

Endoluminal surgery for the treatment of early stage colorectal cancer is typically based on electrocautery tools which imply restrictions on precision and the risk of harm through collateral thermal damage to the healthy tissue. As a potential alternative to mitigate these drawbacks we present laser machining of pig intestine by means of picosecond laser pulses. The high intensities of an ultrafast laser enable nonlinear absorption processes and a predominantly nonthermal ablation regime. Laser ablation results of square cavities with comparable thickness to early stage colorectal cancers are presented for a wavelength of 1030 nm using an industrial picosecond laser. The corresponding histology sections exhibit only minimal collateral damage to the surrounding tissue. The depth of the ablation can be controlled precisely by means of the pulse energy. Overall, the application of ultrafast lasers to ablate pig intestine enables significantly improved precision and reduced thermal damage to the surrounding tissue compared to conventional techniques.

Use of a Piezosurgery Technique to Remove a Deeply Impacted Supernumerary Tooth in the Anterior Maxilla

PubMed Central

Sukegawa, Shintaro; Kanno, Takahiro; Kawakami, Kiyokazu; Shibata, Akane; Takahashi, Yuka; Furuki, Yoshihiko

2015-01-01

Deeply impacted supernumerary teeth in the anterior maxillary cannot be generally removed by the conventional labial or palatal surgical approach because of the risk of damaging the surrounding soft tissues and the possibility of injuring the roots of adjacent permanent teeth. In piezosurgery, bony tissues are selectively cut, thereby avoiding the soft tissue damage caused by rotary cutting instruments. We report the case of a 15-year-old Japanese boy from whom a deeply impacted supernumerary tooth in the anterior maxillary was safely removed through the floor of the nasal cavity. The surgical extraction was performed without damaging the nasal mucosa or adjacent structures such as the roots of the adjacent permanent teeth. Considering that piezosurgery limits the extent of surgical invasion, this technique can be practiced as a minimally invasive and safe surgical procedure for treating suitably selected cases with a deeply impacted supernumerary tooth. PMID:26779355

Advances in prevention of radiation damage to visceral and solid organs in patients requiring radiation therapy of the trunk.

PubMed

Ritter, E F; Lee, C G; Tyler, D; Ferraro, F; Whiddon, C; Rudner, A M; Scully, S

1997-02-01

As a part of multimodality therapy, many patients with tumors of the trunk receive radiation therapy. The major morbidity of this therapy is often secondary to incidental radiation damage to tissues adjacent to treatment areas. We detail our use of saline breast implants placed in polyglycolic acid mesh sheets to displace visceral and solid organs away from the radiation field. Analysis of CT scans and dose volume histograms reveal that this technique successfully displaces uninvolved organs away from the radiation fields, thereby minimizing the radiation dose to such organs and tissues. We believe this is a safe and efficacious method to prevent radiation damage to visceral and solid organs adjacent to trunk tumor sites.

Pulmonary cestodiasis in a cynomolgus monkey (Macaca fascicularis).

PubMed

Guillot, L M; Green, L C

1992-04-01

Cestodiasis in primates has been noted historically to occur quite frequently, although tissue damage and clinical signs may or may not be apparent. Larval cestodes, such as hydatid cysts or cysticercus cysts, are known to cause extensive tissue damage, while other larval cestodes, such as tetrathyridia, cause minimal damage to the host. This case history concerns an apparently healthy cynomolgus monkey that was part of a surgical study. During the study, all parameters were normal. The monkey died 3 hours postsurgery. The apparent cause of death was respiratory arrest. At necropsy, it was discovered there were 1- to 3-mm-diameter cysts, which on transection extruded 2- to 5-mm-long larvae. The larvae could not be positively identified; however, they resembled tetrathyridia of Mesocestoides sp.

Selective removal of esthetic composite restorations with spectral guided laser ablation

NASA Astrophysics Data System (ADS)

Yi, Ivana; Chan, Kenneth H.; Tsuji, Grant H.; Staninec, Michal; Darling, Cynthia L.; Fried, Daniel

2016-02-01

Dental composites are used for a wide range of applications such as fillings for cavities, adhesives for orthodontic brackets, and closure of gaps (diastemas) between teeth by esthetic bonding. Anterior restorations are used to replace missing, diseased and unsightly tooth structure for both appearance and function. When these restorations must be replaced, they are difficult to remove mechanically without causing excessive removal or damage to enamel because dental composites are color matched to teeth. Previous studies have shown that CO2 lasers have high ablation selectivity and are well suited for removal of composite on occlusal surfaces while minimizing healthy tissue loss. A spectral feedback guidance system may be used to discriminate between dental composite and dental hard tissue for selective ablation of composite material. The removal of composite restorations filling diastemas is more challenging due to the esthetic concern for anterior teeth. The objective of this study is to determine if composite spanning a diastema between anterior teeth can be removed by spectral guided laser ablation at clinically relevant rates with minimal damage to peripheral healthy tissue and with higher selectivity than a high speed dental handpiece.

Influence of regeneration method and tissue source on the frequency of somatic variation in Populus to infection by Septoria musiva

Treesearch

Michael E. Ostry; Ronald L. Hackett; Charles H. Michler; R. Serres; B. McCown

1994-01-01

Septoria leaf spot and canker are serious diseases of many hybrid poplar clones in plantations established for biomass production. Developing resistant clones through breeding is the best long-term strategy to minimize tree damage caused by this disease. Tissue culture and somaclonal selection techniques may reduce the time needed to develop disease resistance in...

Feasibility study of modeling liver thermal damage using minimally invasive optical method adequate for in situ measurement.

PubMed

Zhao, Jinzhe; Zhao, Qi; Jiang, Yingxu; Li, Weitao; Yang, Yamin; Qian, Zhiyu; Liu, Jia

2018-06-01

Liver thermal ablation techniques have been widely used for the treatment of liver cancer. Kinetic model of damage propagation play an important role for ablation prediction and real-time efficacy assessment. However, practical methods for modeling liver thermal damage are rare. A minimally invasive optical method especially adequate for in situ liver thermal damage modeling is introduced in this paper. Porcine liver tissue was heated by water bath under different temperatures. During thermal treatment, diffuse reflectance spectrum of liver was measured by optical fiber and used to deduce reduced scattering coefficient (μ ' s ). Arrhenius parameters were obtained through non-isothermal heating approach with damage marker of μ ' s . Activation energy (E a ) and frequency factor (A) was deduced from these experiments. A pair of averaged value is 1.200 × 10 5  J mol -1 and 4.016 × 10 17  s -1 . The results were verified for their reasonableness and practicality. Therefore, it is feasible to modeling liver thermal damage based on minimally invasive measurement of optical property and in situ kinetic analysis of damage progress with Arrhenius model. These parameters and this method are beneficial for preoperative planning and real-time efficacy assessment of liver ablation therapy. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of tissue interactions with mechanical elements of a transscleral drug delivery device.

PubMed

Cohen, Sarah J; Chan, Robison V Paul; Keegan, Mark; Andreoli, Christopher M; Borenstein, Jeffrey T; Miller, Joan W; Gragoudas, Evangelos S

2012-03-12

The goal of this work was to evaluate tissue-device interactions due to implantation of a mechanically operated drug delivery system onto the posterior sclera. Two test devices were designed and fabricated to model elements of the drug delivery device-one containing a free-spinning ball bearing and the other encasing two articulating gears. Openings in the base of test devices modeled ports for drug passage from device to sclera. Porous poly(tetrafluoroethylene) (PTFE) membranes were attached to half of the gear devices to minimize tissue ingrowth through these ports. Test devices were sutured onto rabbit eyes for 10 weeks. Tissue-device interactions were evaluated histologically and mechanically after removal to determine effects on device function and changes in surrounding tissue. Test devices were generally well-tolerated during residence in the animal. All devices encouraged fibrous tissue formation between the sclera and the device, fibrous tissue encapsulation and invasion around the device, and inflammation of the conjunctiva. Gear devices encouraged significantly greater inflammation in all cases and a larger rate of tissue ingrowth. PTFE membranes prevented tissue invasion through the covered drug ports, though tissue migrated in through other smaller openings. The torque required to turn the mechanical elements increased over 1000 times for gear devices, but only on the order of 100 times for membrane-covered gear devices and less than 100 times for ball bearing devices. Maintaining a lower device profile, minimizing microscale motion on the eye surface and covering drug ports with a porous membrane may minimize inflammation, decreasing the risk of damage to surrounding tissues and minimizing disruption of device operation.

Tracheal anastomosis with the diode laser and fibrin tissue adhesive: an in vitro and in vivo investigation.

PubMed

Gleich, L L; Wang, Z; Pankratov, M M; Aretz, H T; Shapshay, S M

1995-05-01

Absorbable sutures have been advocated for tracheal anastomosis to reduce fibrosis and foreign body reaction leading to recurrent stenosis. Fibrin tissue adhesive (FTA) and diode laser welding with indocyanine green-dyed fibrinogen were evaluated in tracheal anastomosis to reduce the number of sutures and to improve healing. In vitro studies demonstrated strong anastomoses with a combination of laser welding and FTA with minimal tissue damage. In a controlled in vivo study, circumferential resections of canine tracheas were repaired with laser welding and FTA augmented with a few stay sutures. These anastomoses had less fibrosis and tissue damage than anastomoses in control animals repaired with sutures alone. This study supports investigation of laser welding and FTA in human beings for tracheal anastomosis and other procedures in which suturing may be difficult.

Optical coherence tomography guided dental drill

DOEpatents

DaSilva, Luiz B.; Colston, Jr., Bill W.; James, Dale L.

2002-01-01

A dental drill that has one or multiple single mode fibers that can be used to image in the vicinity of the drill tip. It is valuable to image below the surface being drilled to minimize damage to vital or normal tissue. Identifying the boundary between decayed and normal enamel (or dentine) would reduce the removal of viable tissue, and identifying the nerve before getting too close with the drill could prevent nerve damage. By surrounding a drill with several optical fibers that can be used by an optical coherence domain reflectometry (OCDR) to image several millimeters ahead of the ablation surface will lead to a new and improved dental treatment device.

Tm:fiber laser ablation with real-time temperature monitoring for minimizing collateral thermal damage: ex vivo dosimetry for ovine brain.

PubMed

Tunc, Burcu; Gulsoy, Murat

2013-01-01

The thermal damage of the surrounding tissue can be an unwanted result of continuous-wave laser irradiations. In order to propose an effective alternative to conventional surgical techniques, photothermal damage must be taken under control by a detailed dose study. Real-time temperature monitoring can be also an effective way to get rid of these negative effects. The aim of the present study is to investigate the potential of a new laser-thermoprobe, which consists of a continuous-wave 1,940-nm Tm:fiber laser and a thermocouple measurement system for brain surgery in an ex vivo study. A laser-thermoprobe was designed for using the near-by tissue temperature as a real-time reference for the applicator. Fresh lamb brain tissues were used for experiments. 320 laser shots were performed on both cortical and subcortical tissue. The relationship between laser parameters, temperature changes, and ablation (removal of tissue) efficiency was determined. The correlation between rate of temperature change and ablation efficiency was calculated. Laser-thermoprobe leads us to understand the basic laser-tissue interaction mechanism in a very cheap and easy way, without making a change in the experimental design. It was also shown that the ablation and coagulation (thermally irreversible damage) diameters could be predicted, and carbonization can be avoided by temperature monitoring. Copyright © 2013 Wiley Periodicals, Inc.

Plasma-mediated ablation for the management of obstructive sleep apnea

NASA Astrophysics Data System (ADS)

Puchalski, Robert; Shah, Udayan K.

2000-05-01

Plasma-mediated ablation (PMA) removes tissue by developing an electrically induced plasma layer between the instrument and target tissue. Charged particles within the plasma field then accelerate toward the tissue, breaking the molecular bonds within the top layer of tissue. Thermal damage to collateral tissue is minimal, resulting in the moniker, 'cold' ablation, for this method. Recently, instrumentation has been developed to permit application for soft tissue resection in Otolaryngology. Presentation of the theory, as well as the benefits and disadvantages associated with CoblationTM technology will be followed by examples of its use. A brief videotape will demonstrate the application of PMA for UPPP, tonsillectomy and nasal turbinate reduction. Preliminary experience from our institution, including eighteen children treated with tonsillectomy and followed for at least one month post-operatively, has provided an initial cohort for comparing the risks and benefits of the approach. The advantage of CoblationTM technology identified thus far, that of less thermal damage, is balanced against a decreased level of hemostasis (compared to MES) and an increased cost.

Smart Polymeric Hydrogels for Cartilage Tissue Engineering: A Review on the Chemistry and Biological Functions.

PubMed

Eslahi, Niloofar; Abdorahim, Marjan; Simchi, Abdolreza

2016-11-14

Stimuli responsive hydrogels (SRHs) are attractive bioscaffolds for tissue engineering. The structural similarity of SRHs to the extracellular matrix (ECM) of many tissues offers great advantages for a minimally invasive tissue repair. Among various potential applications of SRHs, cartilage regeneration has attracted significant attention. The repair of cartilage damage is challenging in orthopedics owing to its low repair capacity. Recent advances include development of injectable hydrogels to minimize invasive surgery with nanostructured features and rapid stimuli-responsive characteristics. Nanostructured SRHs with more structural similarity to natural ECM up-regulate cell-material interactions for faster tissue repair and more controlled stimuli-response to environmental changes. This review highlights most recent advances in the development of nanostructured or smart hydrogels for cartilage tissue engineering. Different types of stimuli-responsive hydrogels are introduced and their fabrication processes through physicochemical procedures are reported. The applications and characteristics of natural and synthetic polymers used in SRHs are also reviewed with an outline on clinical considerations and challenges.

The effects of chronic intracortical microstimulation on neural tissue and fine motor behavior.

PubMed

Rajan, Alexander T; Boback, Jessica L; Dammann, John F; Tenore, Francesco V; Wester, Brock A; Otto, Kevin J; Gaunt, Robert A; Bensmaia, Sliman J

2015-12-01

One approach to conveying sensory feedback in neuroprostheses is to electrically stimulate sensory neurons in the cortex. For this approach to be viable, it is critical that intracortical microstimulation (ICMS) causes minimal damage to the brain. Here, we investigate the effects of chronic ICMS on the neuronal tissue across a variety of stimulation regimes in non-human primates. We also examine each animal's ability to use their hand--the cortical representation of which is targeted by the ICMS--as a further assay of possible neuronal damage. We implanted electrode arrays in the primary somatosensory cortex of three Rhesus macaques and delivered ICMS four hours per day, five days per week, for six months. Multiple regimes of ICMS were delivered to investigate the effects of stimulation parameters on the tissue and behavior. Parameters included current amplitude (10-100 μA), pulse train duration (1, 5 s), and duty cycle (1/1, 1/3). We then performed a range of histopathological assays on tissue near the tips of both stimulated and unstimulated electrodes to assess the effects of chronic ICMS on the tissue and their dependence on stimulation parameters. While the implantation and residence of the arrays in the cortical tissue did cause significant damage, chronic ICMS had no detectable additional effect; furthermore, the animals exhibited no impairments in fine motor control. Chronic ICMS may be a viable means to convey sensory feedback in neuroprostheses as it does not cause significant damage to the stimulated tissue.

The effects of chronic intracortical microstimulation on neural tissue and fine motor behavior

NASA Astrophysics Data System (ADS)

Rajan, Alexander T.; Boback, Jessica L.; Dammann, John F.; Tenore, Francesco V.; Wester, Brock A.; Otto, Kevin J.; Gaunt, Robert A.; Bensmaia, Sliman J.

2015-12-01

Objective. One approach to conveying sensory feedback in neuroprostheses is to electrically stimulate sensory neurons in the cortex. For this approach to be viable, it is critical that intracortical microstimulation (ICMS) causes minimal damage to the brain. Here, we investigate the effects of chronic ICMS on the neuronal tissue across a variety of stimulation regimes in non-human primates. We also examine each animal’s ability to use their hand—the cortical representation of which is targeted by the ICMS—as a further assay of possible neuronal damage. Approach. We implanted electrode arrays in the primary somatosensory cortex of three Rhesus macaques and delivered ICMS four hours per day, five days per week, for six months. Multiple regimes of ICMS were delivered to investigate the effects of stimulation parameters on the tissue and behavior. Parameters included current amplitude (10-100 μA), pulse train duration (1, 5 s), and duty cycle (1/1, 1/3). We then performed a range of histopathological assays on tissue near the tips of both stimulated and unstimulated electrodes to assess the effects of chronic ICMS on the tissue and their dependence on stimulation parameters. Main results. While the implantation and residence of the arrays in the cortical tissue did cause significant damage, chronic ICMS had no detectable additional effect; furthermore, the animals exhibited no impairments in fine motor control. Significance. Chronic ICMS may be a viable means to convey sensory feedback in neuroprostheses as it does not cause significant damage to the stimulated tissue.

A Supramolecular Gel Approach to Minimize the Neural Cell Damage during Cryopreservation Process.

PubMed

Zeng, Jie; Yin, Yixia; Zhang, Li; Hu, Wanghui; Zhang, Chaocan; Chen, Wanyu

2016-03-01

The storage method for living cells is one of the major challenges in cell-based applications. Here, a novel supramolecular gel cryopreservation system (BDTC gel system) is introduced, which can observably increase the neural cell viability during cryopreservation process because this system can (1) confine the ice crystal growth in the porous of BDTC gel system, (2) decrease the amount of ice crystallization and cryopreservation system's freezing point, and (3) reduce the change rates of cell volumes and osmotic shock. In addition, thermoreversible BDTC supramolecular gel is easy to be removed after thawing so it does not hinder the adherence, growth, and proliferation of cells. The results of functionality assessments indicate that BDTC gel system can minimize the neural cell damage during cryopreservation process. This method will be potentially applied in cryopreservation of other cell types, tissues, or organs and will benefit cell therapy, tissue engineering, and organs transplantation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Noise exposure and oxidative balance in auditory and extra-auditory structures in adult and developing animals. Pharmacological approaches aimed to minimize its effects.

PubMed

Molina, S J; Miceli, M; Guelman, L R

2016-07-01

Noise coming from urban traffic, household appliances or discotheques might be as hazardous to the health of exposed people as occupational noise, because may likewise cause hearing loss, changes in hormonal, cardiovascular and immune systems and behavioral alterations. Besides, noise can affect sleep, work performance and productivity as well as communication skills. Moreover, exposure to noise can trigger an oxidative imbalance between reactive oxygen species (ROS) and the activity of antioxidant enzymes in different structures, which can contribute to tissue damage. In this review we systematized the information from reports concerning noise effects on cell oxidative balance in different tissues, focusing on auditory and non-auditory structures. We paid specific attention to in vivo studies, including results obtained in adult and developing subjects. Finally, we discussed the pharmacological strategies tested by different authors aimed to minimize the damaging effects of noise on living beings. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Miniature Forward-imaging B-scan Optical Coherence Tomography Probe to Guide Real-time Laser Ablation

PubMed Central

Li, Zhuoyan; Shen, Jin H.; Kozub, John A.; Prasad, Ratna; Lu, Pengcheng; Joos, Karen M.

2014-01-01

Background and Objective Investigations have shown that pulsed lasers tuned to 6.1 μm in wavelength are capable of ablating ocular and neural tissue with minimal collateral damage. This study investigated whether a miniature B-scan forward-imaging optical coherence tomography (OCT) probe can be combined with the laser to provide real-time visual feedback during laser incisions. Study Design/Methods and Materials A miniature 25-gauge B-scan forward-imaging OCT probe was developed and combined with a 250 μm hollow-glass waveguide to permit delivery of 6.1 μm laser energy. A gelatin mixture and both porcine corneal and retinal tissues were simultaneously imaged and lased (6.1 μm, 10 Hz, 0.4-0.7 mJ) through air. The ablation studies were observed and recorded in real time. The crater dimensions were measured using OCT imaging software (Bioptigen, Durham, NC). Histological analysis was performed on the ocular tissues. Results The combined miniature forward-imaging OCT and mid-infrared laser-delivery probe successfully imaged real-time tissue ablation in gelatin, corneal tissue, and retinal tissue. Application of a constant number of 60 pulses at 0.5 mJ/pulse to the gelatin resulted in a mean crater depth of 123 ± 15 μm. For the corneal tissue, there was a significant correlation between the number of pulses used and depth of the lased hole (Pearson correlation coefficient = 0.82; P = 0.0002). Histological analysis of the cornea and retina tissues showed discrete holes with minimal thermal damage. Conclusions A combined miniature OCT and laser -delivery probe can monitor real-time tissue laser ablation. With additional testing and improvements, this novel instrument has the future possibility of effectively guiding surgeries by simultaneously imaging and ablating tissue. PMID:24648326

Vaginal Speculum For Photodynamic Therapy And Method Of Using The Same

DOEpatents

Tadir, Yona; Berns, Michael W.; Monk, Brad J.; Profeta, Glen; Tromberg, Bruce J.

1995-10-17

An improved vaginal speculum for photodynamic therapy of intraepithelial tissue and in particular vaginal, cervical and vulvar neoplasia utilizes a precisely and accurately positionable optic fiber through which a predetermined dose of light in the range of 620 to 700 nanometers is delivered over a controlled area which has been previously treated with photodynamic therapeutic substances. In particular, the neoplastic area has been treated with hematoporphyrin derivatives and other photosensitizers which are selectively taken into the cancerous tissue. Exposure to the appropriate wavelength laser light photoactivates the absorbed hematoporphyrins causing the release of singlet oxygen which internally oxidizes and ultimately causes cell death. The fiber optic tip from which the laser light is transmitted is precisely positioned within the body cavity at a predetermined distance from the intraepithelial neoplasia in order to obtain the appropriate spot size and location to minimize damage to healthy tissue and maximize damage to the selectively impregnated cancerous tissue.

Optoacoustic monitoring of cutting efficiency and thermal damage during laser ablation.

PubMed

Bay, Erwin; Douplik, Alexandre; Razansky, Daniel

2014-05-01

Successful laser surgery is characterized by a precise cut and effective hemostasis with minimal collateral thermal damage to the adjacent tissues. Consequently, the surgeon needs to control several parameters, such as power, pulse repetition rate, and velocity of movements. In this study we propose utilizing optoacoustics for providing the necessary real-time feedback of cutting efficiency and collateral thermal damage. Laser ablation was performed on a bovine meat slab using a Q-switched Nd-YAG laser (532 nm, 4 kHz, 18 W). Due to the short pulse duration of 7.6 ns, the same laser has also been used for generation of optoacoustic signals. Both the shockwaves, generated due to tissue removal, as well as the normal optoacoustic responses from the surrounding tissue were detected using a single broadband piezoelectric transducer. It has been observed that the rapid reduction in the shockwave amplitude occurs as more material is being removed, indicating decrease in cutting efficiency, whereas gradual decrease in the optoacoustic signal likely corresponds to coagulation around the ablation crater. Further heating of the surrounding tissue leads to carbonization accompanied by a significant shift in the optoacoustic spectra. Our results hold promise for real-time monitoring of cutting efficiency and collateral thermal damage during laser surgery. In practice, this could eventually facilitate development of automatic cut-off mechanisms that will guarantee an optimal tradeoff between cutting and heating while avoiding severe thermal damage to the surrounding tissues.

Evaluation of Tissue Interactions with Mechanical Elements of a Transscleral Drug Delivery Device

PubMed Central

Cohen, Sarah J.; Chan, Robison V. Paul; Keegan, Mark; Andreoli, Christopher M.; Borenstein, Jeffrey T.; Miller, Joan W.; Gragoudas, Evangelos S.

2012-01-01

The goal of this work was to evaluate tissue-device interactions due to implantation of a mechanically operated drug delivery system onto the posterior sclera. Two test devices were designed and fabricated to model elements of the drug delivery device—one containing a free-spinning ball bearing and the other encasing two articulating gears. Openings in the base of test devices modeled ports for drug passage from device to sclera. Porous poly(tetrafluoroethylene) (PTFE) membranes were attached to half of the gear devices to minimize tissue ingrowth through these ports. Test devices were sutured onto rabbit eyes for 10 weeks. Tissue-device interactions were evaluated histologically and mechanically after removal to determine effects on device function and changes in surrounding tissue. Test devices were generally well-tolerated during residence in the animal. All devices encouraged fibrous tissue formation between the sclera and the device, fibrous tissue encapsulation and invasion around the device, and inflammation of the conjunctiva. Gear devices encouraged significantly greater inflammation in all cases and a larger rate of tissue ingrowth. PTFE membranes prevented tissue invasion through the covered drug ports, though tissue migrated in through other smaller openings. The torque required to turn the mechanical elements increased over 1000 times for gear devices, but only on the order of 100 times for membrane-covered gear devices and less than 100 times for ball bearing devices. Maintaining a lower device profile, minimizing microscale motion on the eye surface and covering drug ports with a porous membrane may minimize inflammation, decreasing the risk of damage to surrounding tissues and minimizing disruption of device operation. PMID:24300189

Amniotic fluid stem cells: a promising therapeutic resource for cell-based regenerative therapy.

PubMed

Antonucci, Ivana; Pantalone, Andrea; Tete, Stefano; Salini, Vincenzo; Borlongan, Cesar V; Hess, David; Stuppia, Liborio

2012-01-01

Stem cells have been proposed as a powerful tool in the treatment of several human diseases, both for their ability to represent a source of new cells to replace those lost due to tissue injuries or degenerative diseases, and for the ability of produce trophic molecules able to minimize damage and promote recovery in the injured tissue. Different cell types, such as embryonic, fetal or adult stem cells, human fetal tissues and genetically engineered cell lines, have been tested for their ability to replace damaged cells and to restore the tissue function after transplantation. Amniotic fluid -derived Stem cells (AFS) are considered a novel resource for cell transplantation therapy, due to their high renewal capacity, the "in vitro" expression of embryonic cell lineage markers, and the ability to differentiate in tissues derived from all the three embryonic layers. Moreover, AFS do not produce teratomas when transplanted into animals and are characterized by a low antigenicity, which could represent an advantage for cell transplantation or cell replacement therapy. The present review focuses on the biological features of AFS, and on their potential use in the treatment of pathological conditions such as ischemic brain injury and bone damages.

Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature

PubMed Central

Zhu, Xingjun; Feng, Wei; Chang, Jian; Tan, Yan-Wen; Li, Jiachang; Chen, Min; Sun, Yun; Li, Fuyou

2016-01-01

Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42–45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo. Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy. PMID:26842674

Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature.

PubMed

Zhu, Xingjun; Feng, Wei; Chang, Jian; Tan, Yan-Wen; Li, Jiachang; Chen, Min; Sun, Yun; Li, Fuyou

2016-02-04

Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42-45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo. Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy.

Redox-Modulated Phenomena and Radiation Therapy: The Central Role of Superoxide Dismutases

PubMed Central

Holley, Aaron K.; Miao, Lu; St. Clair, Daret K.

2014-01-01

Abstract Significance: Ionizing radiation is a vital component in the oncologist's arsenal for the treatment of cancer. Approximately 50% of all cancer patients will receive some form of radiation therapy as part of their treatment regimen. DNA is considered the major cellular target of ionizing radiation and can be damaged directly by radiation or indirectly through reactive oxygen species (ROS) formed from the radiolysis of water, enzyme-mediated ROS production, and ROS resulting from altered aerobic metabolism. Recent Advances: ROS are produced as a byproduct of oxygen metabolism, and superoxide dismutases (SODs) are the chief scavengers. ROS contribute to the radioresponsiveness of normal and tumor tissues, and SODs modulate the radioresponsiveness of tissues, thus affecting the efficacy of radiotherapy. Critical Issues: Despite its prevalent use, radiation therapy suffers from certain limitations that diminish its effectiveness, including tumor hypoxia and normal tissue damage. Oxygen is important for the stabilization of radiation-induced DNA damage, and tumor hypoxia dramatically decreases radiation efficacy. Therefore, auxiliary therapies are needed to increase the effectiveness of radiation therapy against tumor tissues while minimizing normal tissue injury. Future Directions: Because of the importance of ROS in the response of normal and cancer tissues to ionizing radiation, methods that differentially modulate the ROS scavenging ability of cells may prove to be an important method to increase the radiation response in cancer tissues and simultaneously mitigate the damaging effects of ionizing radiation on normal tissues. Altering the expression or activity of SODs may prove valuable in maximizing the overall effectiveness of ionizing radiation. Antioxid. Redox Signal. 20, 1567–1589. PMID:24094070

Application of a flexible CO(2) laser fiber for neurosurgery: laser-tissue interactions.

PubMed

Ryan, Robert W; Wolf, Tamir; Spetzler, Robert F; Coons, Stephen W; Fink, Yoel; Preul, Mark C

2010-02-01

The CO(2) laser has an excellent profile for use in neurosurgery. Its high absorption in water results in low thermal spread, sparing adjacent tissue. Use of this laser has been limited to line-of-sight applications because no solid fiber optic cables could transmit its wavelength. Flexible photonic bandgap fiber technology enables delivery of CO(2) laser energy through a flexible fiber easily manipulated in a handheld device. The authors examined and compared the first use of this CO(2) laser fiber to conventional methods for incising neural tissue. Carbon dioxide laser energy was delivered in pulsed or continuous wave settings for different power settings, exposure times, and distances to cortical tissue of 6 anesthetized swine. Effects of CO(2) energy on the tissue were compared with bipolar cautery using a standard pial incision technique, and with scalpel incisions without cautery. Tissue was processed for histological analysis (using H & E, silver staining, and glial fibrillary acidic protein immunohistochemistry) and scanning electron microscopy, and lesion measurements were made. Light microscopy and scanning electron microscopy revealed laser incisions of consistent shape, with central craters surrounded by limited zones of desiccated and edematous tissue. Increased laser power resulted in deeper but not significantly wider incisions. Bipolar cautery lesions showed desiccated and edematous zones but did not incise the pia, and width increased more than depth with higher power. Incisions made without using cautery produced hemorrhage but minimal adjacent tissue damage. The photonic bandgap fiber CO(2) laser produced reliable cortical incisions, adjustable over a range of settings, with minimal adjacent thermal tissue damage. Ease of application under the microscope suggests this laser system has reached true practicality for neurosurgery.

Theranostics and metabolotheranostics for precision medicine in oncology

NASA Astrophysics Data System (ADS)

Bhujwalla, Zaver M.; Kakkad, Samata; Chen, Zhihang; Jin, Jiefu; Hapuarachchige, Sudath; Artemov, Dmitri; Penet, Marie-France

2018-06-01

Most diseases, especially cancer, would significantly benefit from precision medicine where treatment is shaped for the individual. The concept of theragnostics or theranostics emerged around 2002 to describe the incorporation of diagnostic assays into the selection of therapy for this purpose. Increasingly, theranostics has been used for strategies that combine noninvasive imaging-based diagnostics with therapy. Within the past decade theranostic imaging has transformed into a rapidly expanding field that is located at the interface of diagnosis and therapy. A critical need in cancer treatment is to minimize damage to normal tissue. Molecular imaging can be applied to identify targets specific to cancer with imaging, design agents against these targets to visualize their delivery, and monitor response to treatment, with the overall purpose of minimizing collateral damage. Genomic and proteomic profiling can provide an extensive 'fingerprint' of each tumor. With this cancer fingerprint, theranostic agents can be designed to personalize treatment for precision medicine of cancer, and minimize damage to normal tissue. Here, for the first time, we have introduced the term 'metabolotheranostics' to describe strategies where disease-based alterations in metabolic pathways detected by MRS are specifically targeted with image-guided delivery platforms to achieve disease-specific therapy. The versatility of MRI and MRS in molecular and functional imaging makes these technologies especially important in theranostic MRI and 'metabolotheranostics'. Our purpose here is to provide insights into the capabilities and applications of this exciting new field in cancer treatment with a focus on MRI and MRS.

Physiology in Medicine: Understanding dynamic alveolar physiology to minimize ventilator-induced lung injury.

PubMed

Nieman, Gary F; Satalin, Josh; Kollisch-Singule, Michaela; Andrews, Penny; Aiash, Hani; Habashi, Nader M; Gatto, Louis A

2017-06-01

Acute respiratory distress syndrome (ARDS) remains a serious clinical problem with the main treatment being supportive in the form of mechanical ventilation. However, mechanical ventilation can be a double-edged sword: if set improperly, it can exacerbate the tissue damage caused by ARDS; this is known as ventilator-induced lung injury (VILI). To minimize VILI, we must understand the pathophysiologic mechanisms of tissue damage at the alveolar level. In this Physiology in Medicine paper, the dynamic physiology of alveolar inflation and deflation during mechanical ventilation will be reviewed. In addition, the pathophysiologic mechanisms of VILI will be reviewed, and this knowledge will be used to suggest an optimal mechanical breath profile (MB P : all airway pressures, volumes, flows, rates, and the duration that they are applied at both inspiration and expiration) necessary to minimize VILI. Our review suggests that the current protective ventilation strategy, known as the "open lung strategy," would be the optimal lung-protective approach. However, the viscoelastic behavior of dynamic alveolar inflation and deflation has not yet been incorporated into protective mechanical ventilation strategies. Using our knowledge of dynamic alveolar mechanics (i.e., the dynamic change in alveolar and alveolar duct size and shape during tidal ventilation) to modify the MB P so as to minimize VILI will reduce the morbidity and mortality associated with ARDS. Copyright © 2017 the American Physiological Society.

Optical coherence tomography (OCT) guided smart laser knife for cancer surgery (Conference Presentation)

NASA Astrophysics Data System (ADS)

Katta, Nitesh; Mcelroy, Austin; Estrada, Arnold; Milner, Thomas E.

2017-02-01

Neurological cancer surgeries require specialized tools that enhance imaging for precise cutting and removal of tissue without damaging adjacent neurological structures. The novel combination of high-resolution fast optical coherence tomography (OCT) alongside short pulsed nanosecond thulium (Tm) lasers offers stark advantages utilizing the superior beam quality, high volumetric tissue removal rates of thulium lasers with minimal residual thermal footprint in the tissue and avoiding damage to delicate sub-surface structures (e.g., nerves and microvessels); which has not been showcased before. A bench-top system is constructed, using a 15W 1940nm nanosecond pulsed Tm fiber laser (500uJ pulse energy, 100ns pulse duration, 30kHz repetition rate) for removing tissue and a swept source laser (1310±70nm, 100kHz sweep rate) is utilized for OCT imaging, forming a combined Tm/OCT system - a smart laser knife. The OCT image-guidance informs the Tm laser for cutting/removal of targeted tissue structures. Tissue phantoms were constructed to demonstrate surgical incision with blood vessel avoidance on the surface where 2mm wide 600um deep cuts are executed around the vessel using OCT to guide the procedure. Cutting up to delicate subsurface blood vessels (2mm deep) is demonstrated while avoiding damage to their walls. A tissue removal rate of 5mm^3/sec is obtained from the bench-top system. We constructed a blow-off model to characterize Tm cut depths taking into account the absorption coefficients and beam delivery systems to compute Arrhenius damage integrals. The model is used to compare predicted tissue removal rate and residual thermal injury with experimental values in response to Tm laser-tissue modification.

Flexible delivery of Er:YAG radiation at 2.94 µm with negative curvature silica glass fibers: a new solution for minimally invasive surgical procedures.

PubMed

Urich, A; Maier, R R J; Yu, Fei; Knight, J C; Hand, D P; Shephard, J D

2013-02-01

We present the delivery of high energy microsecond pulses through a hollow-core negative-curvature fiber at 2.94 µm. The energy densities delivered far exceed those required for biological tissue manipulation and are of the order of 2300 J/cm(2). Tissue ablation was demonstrated on hard and soft tissue in dry and aqueous conditions with no detrimental effects to the fiber or catastrophic damage to the end facets. The energy is guided in a well confined single mode allowing for a small and controllable focused spot delivered flexibly to the point of operation. Hence, a mechanically and chemically robust alternative to the existing Er:YAG delivery systems is proposed which paves the way for new routes for minimally invasive surgical laser procedures.

Tapered fiber optic applicator for laser ablation: Theoretical and experimental assessment of thermal effects on ex vivo model.

PubMed

Saccomandi, P; Di Matteo, F M; Schena, E; Quero, G; Massaroni, C; Giurazza, F; Costamagna, G; Silvestri, S

2017-07-01

Laser Ablation (LA) is a minimally invasive technique for tumor removal. The laser light is guided into the target tissue by a fiber optic applicator; thus the physical features of the applicator tip strongly influence size and shape of the tissue lesion. This study aims to verify the geometry of the lesion achieved by a tapered-tip applicator, and to investigate the percentage of thermally damaged cells induced by the tapered-tip fiber optic applicator. A theoretical model was implemented to simulate: i) the distribution of laser light fluence rate in the tissue through Monte Carlo method, ii) the induced temperature distribution, by means of the Bio Heat Equation, iii) the tissue injury, by Arrhenius integral. The results obtained by the implementation of the theoretical model were experimentally assessed. Ex vivo porcine liver underwent LA with tapered-tip applicator, at different laser settings (laser power of 1 W and 1.7 W, deposited energy equal to 330 J and 500 J, respectively). Almost spherical volume lesions were produced. The thermal damage was assessed by measuring the diameter of the circular-shaped lesion. The comparison between experimental results and theoretical prediction shows that the thermal damage discriminated by visual inspection always corresponds to a percentage of damaged cells of 96%. A tapered-tip applicator allows obtaining localized and reproducible damage close to spherical shape, whose diameter is related to the laser settings, and the simple theoretical model described is suitable to predict the effects, in terms of thermal damage, on ex vivo liver. Further trials should be addressed to adapt the model also on in vivo tissue, aiming to develop a tool useful to support the physician in clinical application of LA.

Optimized path planning for soft tissue resection via laser vaporization

NASA Astrophysics Data System (ADS)

Ross, Weston; Cornwell, Neil; Tucker, Matthew; Mann, Brian; Codd, Patrick

2018-02-01

Robotic and robotic-assisted surgeries are becoming more prevalent with the promise of improving surgical outcomes through increased precision, reduced operating times, and minimally invasive procedures. The handheld laser scalpel in neurosurgery has been shown to provide a more gentle approach to tissue manipulation on or near critical structures over classical tooling, though difficulties of control have prevented large scale adoption of the tool. This paper presents a novel approach to generating a cutting path for the volumetric resection of tissue using a computer-guided laser scalpel. A soft tissue ablation simulator is developed and used in conjunction with an optimization routine to select parameters which maximize the total resection of target tissue while minimizing the damage to surrounding tissue. The simulator predicts the ablative properties of tissue from an interrogation cut for tuning and simulates the removal of a tumorous tissue embedded on the surface of healthy tissue using a laser scalpel. We demonstrate the ability to control depth and smoothness of cut using genetic algorithms to optimize the ablation parameters and cutting path. The laser power level, cutting rate and spacing between cuts are optimized over multiple surface cuts to achieve the desired resection volumes.

A combination of experimental measurement, constitutive damage model, and diffusion tensor imaging to characterize the mechanical properties of the human brain.

PubMed

Karimi, Alireza; Rahmati, Seyed Mohammadali; Razaghi, Reza

2017-09-01

Understanding the mechanical properties of the human brain is deemed important as it may subject to various types of complex loadings during the Traumatic Brain Injury (TBI). Although many studies so far have been conducted to quantify the mechanical properties of the brain, there is a paucity of knowledge on the mechanical properties of the human brain tissue and the damage of its axon fibers under the various types of complex loadings during the Traumatic Brain Injury (TBI). Although many studies so far have been conducted to quantify the mechanical properties of the brain, there is a paucity of knowledge on the mechanical properties of the human brain tissue and the damage of its axon fibers under the frontal lobe of the human brain. The constrained nonlinear minimization method was employed to identify the brain coefficients according to the axial and transversal compressive data. The pseudo-elastic damage model data was also well compared with that of the experimental data and it not only up to the primary loading but also the discontinuous softening could well address the mechanical behavior of the brain tissue.

Spinal cord deformation due to nozzle gas flow effects using optical coherence tomography

NASA Astrophysics Data System (ADS)

Wong, Ronnie J.; Jivraj, Jamil; Vuong, Barry; Ramjist, Joel; Sun, Cuiru; Huang, Yize; Yang, Victor X. D.

2015-03-01

The use of gas assistance in laser machining hard materials is well established in manufacturing but not in the context of surgery. Laser cutting of osseous tissue in the context of neurosurgery can benefit from gas-assist but requires an understanding of flow and pressure effects to minimize neural tissue damage. In this study we acquire volumetric flow rates through a gas nozzle on the spinal cord, with dura and without dura.

Injectable hydrogels for cartilage and bone tissue engineering

PubMed Central

Liu, Mei; Zeng, Xin; Ma, Chao; Yi, Huan; Ali, Zeeshan; Mou, Xianbo; Li, Song; Deng, Yan; He, Nongyue

2017-01-01

Tissue engineering has become a promising strategy for repairing damaged cartilage and bone tissue. Among the scaffolds for tissue-engineering applications, injectable hydrogels have demonstrated great potential for use as three-dimensional cell culture scaffolds in cartilage and bone tissue engineering, owing to their high water content, similarity to the natural extracellular matrix (ECM), porous framework for cell transplantation and proliferation, minimal invasive properties, and ability to match irregular defects. In this review, we describe the selection of appropriate biomaterials and fabrication methods to prepare novel injectable hydrogels for cartilage and bone tissue engineering. In addition, the biology of cartilage and the bony ECM is also summarized. Finally, future perspectives for injectable hydrogels in cartilage and bone tissue engineering are discussed. PMID:28584674

Greater inadvertent muscle damage in direct anterior approach when compared with the direct superior approach for total hip arthroplasty.

PubMed

Amanatullah, D F; Masini, M A; Roger, D J; Pagnano, M W

2016-08-01

We wished to quantify the extent of soft-tissue damage sustained during minimally invasive total hip arthroplasty through the direct anterior (DA) and direct superior (DS) approaches. In eight cadavers, the DA approach was performed on one side, and the DS approach on the other, a single brand of uncemented hip prosthesis was implanted by two surgeons, considered expert in their surgical approaches. Subsequent reflection of the gluteus maximus allowed the extent of muscle and tendon damage to be measured and the percentage damage to each anatomical structure to be calculated. The DA approach caused substantially greater damage to the gluteus minimus muscle and tendon when compared with the DS approach (t-test, p = 0.049 and 0.003, respectively). The tensor fascia lata and rectus femoris muscles were damaged only in the DA approach. There was no difference in the amount of damage to the gluteus medius muscle and tendon, piriformis tendon, obturator internus tendon, obturator externus tendon or quadratus femoris muscle between approaches. The posterior soft-tissue releases of the DA approach damaged the gluteus minimus muscle and tendon, piriformis tendon and obturator internus tendon. The DS approach caused less soft-tissue damage than the DA approach. However the clinical relevance is unknown. Further clinical outcome studies, radiographic evaluation of component position, gait analyses and serum biomarker levels are necessary to evaluate and corroborate the safety and efficacy of the DS approach. Cite this article: Bone Joint J 2016;98-B1036-42. ©2016 The British Editorial Society of Bone & Joint Surgery.

Optical clearing of vaginal tissues

NASA Astrophysics Data System (ADS)

Chang, Chun-Hung; Myers, Erinn M.; Kennelly, Michael J.; Fried, Nathaniel M.

2017-02-01

Near-IR laser energy in conjunction with applied tissue cooling is being investigated for thermal remodeling of endopelvic fascia during minimally invasive treatment of female stress urinary incontinence. Previous simulations of light transport, heat transfer, and tissue thermal damage have shown that a transvaginal approach is more feasible than a transurethral approach. However, undesirable thermal insult to vaginal wall was predicted. This study explores whether an optical clearing agent (OCA) can improve optical penetration depth and completely preserve vaginal wall during subsurface treatment of endopelvic fascia. Several OCA mixtures were tested, and 100% glycerol was found to be optimal. Optical transmission studies, optical coherence tomography, reflection spectroscopy, and computer simulations of thermal damage to tissue using glycerol were performed. The OCA produced a 61% increase in optical transmission through porcine vaginal wall at 37 °C after 30 min. Monte Carlo (MC) light transport, heat transfer, and Arrhenius integral thermal damage simulations were performed. MC model showed improved energy deposition in endopelvic fascia using OCA. Without OCA, 62, 37, and 1% of energy was deposited in vaginal wall, endopelvic fascia, and urethral wall, compared with 50, 49, and 1% with OCA. Use of OCA also yielded 0.5 mm increase in treatment depth, allowing potential thermal tissue remodeling at 3 mm depth.

Photothermal lesions in soft tissue induced by optical fiber microheaters.

PubMed

Pimentel-Domínguez, Reinher; Moreno-Álvarez, Paola; Hautefeuille, Mathieu; Chavarría, Anahí; Hernández-Cordero, Juan

2016-04-01

Photothermal therapy has shown to be a promising technique for local treatment of tumors. However, the main challenge for this technique is the availability of localized heat sources to minimize thermal damage in the surrounding healthy tissue. In this work, we demonstrate the use of optical fiber microheaters for inducing thermal lesions in soft tissue. The proposed devices incorporate carbon nanotubes or gold nanolayers on the tips of optical fibers for enhanced photothermal effects and heating of ex vivo biological tissues. We report preliminary results of small size photothermal lesions induced on mice liver tissues. The morphology of the resulting lesions shows that optical fiber microheaters may render useful for delivering highly localized heat for photothermal therapy.

Use of the holmium:YAG laser in urology

NASA Astrophysics Data System (ADS)

Mattioli, Stefano

1997-12-01

The Holmium-YAG is a versatile laser with multiple soft- tissue applications including tissue incision and vaporization, and pulsed-laser applications such as lithotripsy. At 2140 nanometers, the wavelength is highly absorbed by tissue water. Further, like CO2 laser, the Holmium produces immediate tissue vaporization while minimizing deep thermal damage to surrounding tissues. It is an excellent instrument for endopyelotomy, internal urethrotomy, bladder neck incisions and it can be used to resect the prostate. The Holmium creates an acute TUR defect which gives immediate results like the TURP. More than 50 patients were treated from Jan. 1996 to Jan. 1997 for obstructive symptoms due to benign prostatic hyperplasia, bladder neck stricture, urethral stenosis, and superficial bladder tumors.

Aggregatibacter actinomycetemcomitans osteomyelitis in a 12 year old boy: case report emphasizing the importance of tissue culture, and review of literature.

PubMed

Sharma, Ketaki; Mudgil, Poonam; Whitehall, John S; Gosbell, Iain

2017-03-14

Aggregatibacter actinomycetemcomitans most commonly causes periodontitis but has been reported to infect heart valves, soft tissue, brain and lungs, and distal bones. Osteomyelitis distal to the jaw is rarely described. We report an unusual and rare case of chronic osteomyelitis caused by A. actinomycetemcomitans in the toe of a paediatric patient, and review the available literature. The infection was managed with intravenous antibiotics followed by oral antibiotics. This is an unusual presentation of A. actinomycetemcomitans causing chronic osteomyelitis presumed due to nidation in a minimally damaged bone, associated with bacteraemia of an oral commensal. It occurred in the toe, without obvious dental predisposition; associated with minimal clinical disturbance and with muted immune response.

A comparison of plants and animals in their responses to risk of consumption.

PubMed

Karban, Richard; Orrock, John L; Preisser, Evan L; Sih, Andrew

2016-08-01

Both plants and animals reduce their risk of being eaten by detecting and responding to herbivore and predator cues. Plants tend to be less mobile and rely on more local information perceived with widely dispersed and redundant tissues. As such, plants can more easily multi-task. Plants are more tolerant of damage and use damage to their own tissues as reliable cues of risk; plants have a higher threshold before responding to the threat of herbivory. Plants also use diverse cues that include fragments of plant tissue and molecular patterns from herbivores, herbivore feeding, or microbial associates of herbivores. Instead of fleeing from attackers, plants reallocate valuable resources to organs at less risk. They minimize unnecessary defenses against unrealized risks and costs of failing to defend against actual risk. Plants can remember and learn, although these abilities are poorly understood. Copyright © 2016 Elsevier Ltd. All rights reserved.

Endoscopic diode-laser applications in airway surgery

NASA Astrophysics Data System (ADS)

Pankratov, Michail M.; Wang, Zhi; Rebeiz, Elie E.; Perrault, Donald F., Jr.; Shapshay, Stanley M.; Gleich, Lyon L.

1994-09-01

A technique was developed to secure small mucosal grafts onto the airway wound with fibrin/albumin tissue adhesive mixed with ICG dye and irradiated with a 810 nm diode laser. An in vitro study of the tensile strength produced strong mucosal soldering which was adequate to fix grafts in place. In vivo studies showed that wounds with mucosal grafts were completely covered by regenerated squamous cells in 1 week and by ciliated epithelium in 2 weeks. Excellent healing was observed at 6 and 14 days postoperatively and the histology at 28 days found normal epithelium over the vocal cord lesion. This soldering technique is a less traumatic treatment for patients with extensive lesions of the larynx of various origin. Diode laser soldering with ICG-doped fibrin tissue adhesive was evaluated in tracheal anastomosis as a substitute for absorbable sutures. In vitro studies demonstrated strong anastomoses with minimal tissue damage. In vivo animal study showed that these anastomoses had less fibrosis and tissue damage than control animals repaired with sutures only.

SU-8 microprobe with microelectrodes for monitoring electrical impedance in living tissues.

PubMed

Tijero, M; Gabriel, G; Caro, J; Altuna, A; Hernández, R; Villa, R; Berganzo, J; Blanco, F J; Salido, R; Fernández, L J

2009-04-15

This paper presents a minimally invasive needle-shaped probe capable of monitoring the electrical impedance of living tissues. This microprobe consists of a 160 microm thick SU-8 substrate containing four planar platinum (Pt) microelectrodes. We design the probe to minimize damage to the surrounding tissue and to be stiff enough to be inserted in living tissues. The proposed batch fabrication process is low cost and low time consuming. The microelectrodes obtained with this process are strongly adhered to the SU-8 substrate and their impedance does not depend on frequency variation. In vitro experiments are compared with previously developed Si and SiC based microprobes and results suggest that it is preferable to use the SU-8 based microprobes due to their flexibility and low cost. The microprobe is assembled on a flexible printed circuit FPC with a conductive glue, packaged with epoxy and wired to the external instrumentation. This flexible probe is inserted into a rat kidney without fracturing and succeeds in demonstrating the ischemia monitoring.

Checkpoint Inhibitor Sensitizes Human Tumor Cells | Center for Cancer Research

Cancer.gov

One unfortunate and detrimental side effect of ionizing radiation as a treatment for cancer is the damage it imparts to normal tissue near the targeted tumor. Technology has improved radiation delivery, minimizing the volume of normal tissue in the radiation field, but has not eliminated it completely. Thus, the identification of drugs that increase the sensitivity of cancer cells to radiation while sparing normal cells would go a long way toward improving patient quality of life and outcome.

High-frequency microwave ablation method for enhanced cancer treatment with minimized collateral damage.

PubMed

Yoon, Jeonghoon; Cho, Jeiwon; Kim, Namgon; Kim, Dae-Duk; Lee, Eunsook; Cheon, Changyul; Kwon, Youngwoo

2011-10-15

To overcome the limits of conventional microwave ablation, a new frequency spectrum above 6 GHz has been explored for low-power and low collateral damage ablation procedure. A planar coaxial probe-based applicator, suitable for easy insertion into the human body, was developed for our study to cover a wideband frequency up to 30 GHz. Thermal ablations with small input power (1-3 W) at various microwave frequencies were performed on nude mice xenografted with human breast cancer. Comparative study of ablation efficiencies revealed that 18-GHz microwave results in the largest difference in the temperature rise between cancer and normal tissues as well as the highest ablation efficiency, reaching 20 times that of 2 GHz. Thermal profile study on the composite region of cancer and fat also showed significantly reduced collateral damage using 18 GHz. Application of low-power (1 W) 18-GHz microwave on the nude mice xenografted with human breast cancer cells resulted in recurrence-free treatment. The proposed microwave ablation method can be a very effective process to treat small-sized tumor with minimized invasiveness and collateral damages. Copyright © 2010 UICC.

Selective removal of dental composite using a rapidly scanned carbon dioxide laser

NASA Astrophysics Data System (ADS)

Chan, Kenneth H.; Fried, Daniel

2011-03-01

Dental restorative materials are color matched to the tooth and are difficult to remove by mechanical means without excessive removal or damage to peripheral enamel and dentin. Lasers are ideally suited for selective ablation to minimize healthy tissue loss when replacing existing restorations, sealants or removing composite adhesives such as residual composite left after debonding orthodontic brackets. In this study a carbon dioxide laser operating at high laser pulse repetition rates integrated with a galvanometer based scanner was used to selectively remove composite from tooth surfaces. A diode array spectrometer was used to measure the plume emission after each laser pulse and determine if the ablated material was tooth mineral or composite. The composite was placed on tooth buccal and occlusal surfaces and the carbon dioxide laser was scanned across the surface to selectively remove the composite without excessive damage to the underlying sound enamel. The residual composite and the damage to the underlying enamel was evaluated using optical microscopy. The laser was able to rapidly remove the composites rapidly from both surfaces with minimal damage to the underlying sound enamel.

The effect of micro-ECoG substrate footprint on the meningeal tissue response

NASA Astrophysics Data System (ADS)

Schendel, Amelia A.; Nonte, Michael W.; Vokoun, Corinne; Richner, Thomas J.; Brodnick, Sarah K.; Atry, Farid; Frye, Seth; Bostrom, Paige; Pashaie, Ramin; Thongpang, Sanitta; Eliceiri, Kevin W.; Williams, Justin C.

2014-08-01

Objective. There is great interest in designing implantable neural electrode arrays that maximize function while minimizing tissue effects and damage. Although it has been shown that substrate geometry plays a key role in the tissue response to intracortically implanted, penetrating neural interfaces, there has been minimal investigation into the effect of substrate footprint on the tissue response to surface electrode arrays. This study investigates the effect of micro-electrocorticography (micro-ECoG) device geometry on the longitudinal tissue response. Approach. The meningeal tissue response to two micro-ECoG devices with differing geometries was evaluated. The first device had each electrode site and trace individually insulated, with open regions in between, while the second device had a solid substrate, in which all 16 electrode sites were embedded in a continuous insulating sheet. These devices were implanted bilaterally in rats, beneath cranial windows, through which the meningeal tissue response was monitored for one month after implantation. Electrode site impedance spectra were also monitored during the implantation period. Main results. It was observed that collagenous scar tissue formed around both types of devices. However, the distribution of the tissue growth was different between the two array designs. The mesh devices experienced thick tissue growth between the device and the cranial window, and minimal tissue growth between the device and the brain, while the solid device showed the opposite effect, with thick tissue forming between the brain and the electrode sites. Significance. These data suggest that an open architecture device would be more ideal for neural recording applications, in which a low impedance path from the brain to the electrode sites is critical for maximum recording quality.

Skin welding using pulsed laser radiation and a dye

NASA Astrophysics Data System (ADS)

Fried, Nathaniel M.; Walsh, Joseph T., Jr.

1998-07-01

Previous skin welding studies have used continuous wave (CW) delivery of radiation. However, heat diffusion during irradiation prevents strong welds from being achieved without creating large zones of thermal damage to surrounding tissue. This damage may prevent normal wound healing. Strong welds and minimal thermal damage can be achieved by introducing a dye and delivering the radiation in a pulsed mode. Two-cm-long, full-thickness incisions were made in guinea pig skin. India ink was used as an absorber, and egg white albumin was used as an adhesive. A 5-mm-diameter spot of CW, 1.06-micrometer Nd:YAG laser radiation was scanned over the weld site, producing 100 millisecond pulses. The cooling time between scans and number of scans was varied. Thermal damage zones were measured using a transmission polarizing microscope to identify birefringence changes in tissue. Tensile strengths were measured using a tensiometer. For pulsed welding and long cooling times, weld strengths of 2.4 kg/cm2 were measured, and thermal damage to the epidermis was limited to approximately 500 micrometers. With CW welding, comparable weld strengths resulted in approximately 2700 micrometer of thermal damage. CW laser radiation weld strengths were only 0.6 kg/cm2 when thermal damage in the epidermis was limited to approximately 500 micrometers.

HISTOLOGICAL STUDIES OF THE EFFECTS OF CHRONIC IMPLANTATION OF CERAMIC-BASED MICROELECTRODE ARRAYS AND MICRODIALYSIS PROBES IN RAT PREFRONTAL CORTEX

PubMed Central

Hascup, Erin R.; Bjerkén, Sara af; Hascup, Kevin N.; Pomerleau, Francois; Huettl, Peter; Strömberg, Ingrid; Gerhardt, Greg A.

2010-01-01

Chronic implantation of neurotransmitter measuring devices is essential for awake, behavioral studies occurring over multiple days. Little is known regarding the effects of long term implantation on surrounding brain parenchyma and the resulting alterations in the functional properties of this tissue. We examined the extent of tissue damage produced by chronic implantation of either ceramic microelectrode arrays (MEAs) or microdialysis probes. Histological studies were carried out on fixed tissues using stains for neurons (cresyl violet), astrocytes (GFAP), microglia (Iba-1), glutamatergic nerve fibers (VGLUT1), and the blood-brain barrier (SMI-71). Nissl staining showed pronounced tissue body loss with microdialysis implants compared to MEAs. The MEAs produced mild gliosis extending 50–100 µm from the tracks, with a significant change in the affected areas starting at 3 days. By contrast, the microdialysis probes produced gliosis extending 200–300 µm from the track, which was significant at 3 and 7 days. Markers for microglia and glutamatergic fibers supported that the MEAs produce minimal damage with significant changes occurring only at 3 and 7 days that return to control levels by one month. SMI-71 staining supported integrity of the blood brain barrier out to 1 week for both the microdialysis probes and the MEAs. This data support that the ceramic MEAs small size and biocompatibility are necessary to accurately measure neurotransmitter levels in the intact brain. The minimal invasiveness of the MEAs reduce tissue loss, allowing for long term (>6 month) electrochemical and electrophysiological monitoring of brain activity. PMID:19577548

Fabrication of novel bundled fiber and performance assessment for clinical applications.

PubMed

Kim, Changhwan; Jeon, Myung Jin; Jung, Jin Hyang; Yang, Jung Dug; Park, Hoyong; Kang, Hyun Wook; Lee, Ho

2014-11-01

During laser vaporization of benign prostate hyperplasia (BPH), high precision of optical fiber handling is pivotal to minimize any post-operative complications. The aim of the study was to evaluate the feasible applications of a bundled fiber to treat BPH by directionally and selectively manipulating laser light onto the targeted tissue. A bundled optical fiber, consisting of four side-firing fibers, was fabricated to selectively emit laser beams in from one to four directions. Both transmission efficiency and light distribution were qualitatively and quantitatively characterized on the bundled fiber. In terms of interstitial application of the proposed fiber with 1064 nm on porcine liver tissue, the extent of thermal denaturation was estimated and compared at various laser parameterizations and for different directions of light. From the laser source to the fiber tip, the fabricated fiber device demonstrated a total light transmission of 52%. Due to internal light reflection, a secondary beam was emitted backward from the fiber tip and was responsible for 25% of the transmission loss. According to tissue testing, the extent of tissue denaturation generally increased with laser power, irradiation time, and number of light directions. The geometrical shape of thermal coagulation correlated well with the direction of light emission. Thermal damage to the glass tube occurred during excessive heat accumulation generated by continuous irradiation. The proposed fiber can be beneficial for laser vaporization of BPH by providing a selective light direction irradiation along with minimal thermal damage. Further studies will extend the applicability of the bundled fiber to treat tubular tissue structure. © 2014 Wiley Periodicals, Inc.

Retro-peritoneal cooling for kidney preservation from multi-organ cadaver donors.

PubMed

Salazar-Bañuelos, Anastasio; Monroy-Cuadros, Mauricio; Henriquez-Cooper, Hoover

2018-05-01

Minimizing ischemia is paramount in the procurement of kidneys for transplantation. A fast cooling and expeditious removal is ideal to minimize damage from warm ischemia, however, since the removal of kidneys is delayed in cadaver donation until all other organs are harvested, the risk of kidney damage increases due to contact with the warmer soft body tissues. Surgical techniques that expedite organ retrieval were developed to avoid organ damage. We test a modification of Thomas Starzl's improved technique for multi-organ harvesting by interposing an ice bag between the posterior aspect of the kidney and the psoas muscle in a randomized trial with 21 multi-organ cadaver donors. The modified technique decreases the extraction temperature of the kidneys significantly in comparison with the controls, p < .001. This simple technique improves the preservation of kidneys from cadaver donors, and can potentially have more impact on multi-organ donation after cardiac death. Copyright © 2018 Elsevier Inc. All rights reserved.

Periscopic Spine Surgery

DTIC Science & Technology

2007-01-01

radiation therapy In radiation therapy , the overarching goal is to deliver a lethal dose to the cancerous tissue while minimizing collateral damage to the ...Computer is shown in Figure 6. The exercise protocol is first parsed into a control mode based on the desired activation of configuration space variables...ABSTRACT In this paper, we present the design and implementation of a

Minimizing yellow-bellied sapsucker damage

Treesearch

Gayne G. Erdmann; Ralph M., Jr. Peterson

1992-01-01

The yellow-bellied sapsucker is a migratory woodpecker that feeds on a wide variety of orchard, shade, and forest trees. Instead of drilling holes to find insects like other woodpeckers, sapsuckers drill holes in living trees to feed on sap and phloem tissues. Yellow and paper birches are their favorite summer food sources on their nesting grounds in Upper Michigan and...

Optical clearing of vaginal tissues, ex vivo, for minimally invasive laser treatment of female stress urinary incontinence

NASA Astrophysics Data System (ADS)

Chang, Chun-Hung; Myers, Erinn M.; Kennelly, Michael J.; Fried, Nathaniel M.

2017-01-01

Near-infrared laser energy in conjunction with applied tissue cooling is being investigated for thermal remodeling of the endopelvic fascia during minimally invasive treatment of female stress urinary incontinence. Previous computer simulations of light transport, heat transfer, and tissue thermal damage have shown that a transvaginal approach is more feasible than a transurethral approach. However, results were suboptimal, and some undesirable thermal insult to the vaginal wall was still predicted. This study uses experiments and computer simulations to explore whether application of an optical clearing agent (OCA) can further improve optical penetration depth and completely preserve the vaginal wall during subsurface treatment of the endopelvic fascia. Several different mixtures of OCA's were tested, and 100% glycerol was found to be the optimal agent. Optical transmission studies, optical coherence tomography, reflection spectroscopy, and computer simulations [including Monte Carlo (MC) light transport, heat transfer, and Arrhenius integral model of thermal damage] using glycerol were performed. The OCA produced a 61% increase in optical transmission through porcine vaginal wall at 37°C after 30 min. The MC model showed improved energy deposition in endopelvic fascia using glycerol. Without OCA, 62%, 37%, and 1% of energy was deposited in vaginal wall, endopelvic fascia, and urethral wall, respectively, compared with 50%, 49%, and 1% using OCA. Use of OCA also resulted in 0.5-mm increase in treatment depth, allowing potential thermal tissue remodeling at a depth of 3 mm with complete preservation of the vaginal wall.

Acetylsalicylic acid (aspirin) reduces damage to reconstituted human tissues infected with Candida species by inhibiting extracellular fungal lipases

PubMed Central

Trofa, David; Agovino, Mariangela; Stehr, Frank; Schäfer, Wilhelm; Rykunov, Dmitry; Fiser, András; Hamari, Zsuzsanna; Nosanchuk, Joshua D.; Gácser, Attila

2009-01-01

A reconstituted human tissue model was used to mimic Candida albicans and Candida parapsilosis infection in order to investigate the protective effects of acetylsalicylic acid (aspirin, ASA). We found that therapeutic concentrations of ASA reduced tissue damage in the in vitro infection model. We further evaluated the lipase inhibitory effects of ASA by investigating the growth of C. albicans, C. parapsilosis and C. parapsilosis lipase negative (Δcplip1-2/Δcplip1-2) mutants in a lipid rich minimal medium supplemented with olive oil and found that a therapeutic concentration of ASA inhibited the growth of wild type fungi. The lipase inhibitors quinine and ebelactone B were also shown to reduce growth and protect against tissue damage from Candida species, respectively. A lipolytic activity assay also showed that therapeutic concentrations of ASA inhibited C. antarctica and C. cylindracea purified lipases obtained through a commercial kit. The relationship between ASA and lipase was characterized through a computed structural model of the Lipase-2 protein from C. parapsilosis in complex with ASA. The results suggest that development of inhibitors of fungal lipases could result in broad-spectrum therapeutics, especially since fungal lipases are not homologous to their human analogues. PMID:19703582

New paradigms and future challenges in Radiation Oncology: An Update of Biological Targets and Technology*

PubMed Central

Liauw, Stanley L.; Connell, Philip P.; Weichselbaum, Ralph R.

2013-01-01

The primary objective of radiation oncology is to exploit the biological interaction of radiation within tissue to promote tumor death while minimizing damage to surrounding normal tissue. The clinical delivery of radiation relies on principles of radiation physics that define how radiation energy is deposited in the body, as well as technology that facilitates accurate tumor targeting. This review will summarize the current landscape of recent biological and technological advances in radiation oncology, describe the challenges that exist, and offer potential avenues for improvement. PMID:23427246

Photothermal effects of laser tissue soldering.

PubMed

McNally, K M; Sorg, B S; Welch, A J; Dawes, J M; Owen, E R

1999-04-01

Low-strength anastomoses and thermal damage of tissue are major concerns in laser tissue welding techniques where laser energy is used to induce thermal changes in the molecular structure of the tissues being joined, hence allowing them to bond together. Laser tissue soldering, on the other hand, is a bonding technique in which a protein solder is applied to the tissue surfaces to be joined, and laser energy is used to bond the solder to the tissue surfaces. The addition of protein solders to augment tissue repair procedures significantly reduces the problems of low strength and thermal damage associated with laser tissue welding techniques. Investigations were conducted to determine optimal solder and laser parameters for tissue repair in terms of tensile strength, temperature rise and damage and the microscopic nature of the bonds formed. An in vitro study was performed using an 808 nm diode laser in conjunction with indocyanine green (ICG)-doped albumin protein solders to repair bovine aorta specimens. Liquid and solid protein solders prepared from 25% and 60% bovine serum albumin (BSA), respectively, were compared. The efficacy of temperature feedback control in enhancing the soldering process was also investigated. Increasing the BSA concentration from 25% to 60% greatly increased the tensile strength of the repairs. A reduction in dye concentration from 2.5 mg ml(-1) to 0.25 mg ml(-1) was also found to result in an increase in tensile strength. Increasing the laser irradiance and thus surface temperature resulted in an increased severity of histological injury. Thermal denaturation of tissue collagen and necrosis of the intimal layer smooth muscle cells increased laterally and in depth with higher temperatures. The strongest repairs were produced with an irradiance of 6.4 W cm(-2) using a solid protein solder composed of 60% BSA and 0.25 mg ml(-1) ICG. Using this combination of laser and solder parameters, surface temperatures were observed to reach 85+/-5 degrees C with a maximum temperature difference through the 150 microm thick solder strips of about 15 degrees C. Histological examination of the repairs formed using these parameters showed negligible evidence of collateral thermal damage to the underlying tissue. Scanning electron microscopy suggested albumin intertwining within the tissue collagen matrix and subsequent fusion with the collagen as the mechanism for laser tissue soldering. The laser tissue soldering technique is shown to be an effective method for producing repairs with improved tensile strength and minimal collateral thermal damage over conventional laser tissue welding techniques.

Role of the immune system in cardiac tissue damage and repair following myocardial infarction.

PubMed

Saparov, Arman; Ogay, Vyacheslav; Nurgozhin, Talgat; Chen, William C W; Mansurov, Nurlan; Issabekova, Assel; Zhakupova, Jamilya

2017-09-01

The immune system plays a crucial role in the initiation, development, and resolution of inflammation following myocardial infarction (MI). The lack of oxygen and nutrients causes the death of cardiomyocytes and leads to the exposure of danger-associated molecular patterns that are recognized by the immune system to initiate inflammation. At the initial stage of post-MI inflammation, the immune system further damages cardiac tissue to clear cell debris. The excessive production of reactive oxygen species (ROS) by immune cells and the inability of the anti-oxidant system to neutralize ROS cause oxidative stress that further aggravates inflammation. On the other hand, the cells of both innate and adaptive immune system and their secreted factors are critically instrumental in the very dynamic and complex processes of regulating inflammation and mediating cardiac repair. It is important to decipher the balance between detrimental and beneficial effects of the immune system in MI. This enables us to identify better therapeutic targets for reducing the infarct size, sustaining the cardiac function, and minimizing the likelihood of heart failure. This review discusses the role of both innate and adaptive immune systems in cardiac tissue damage and repair in experimental models of MI.

Evaluation of effectiveness of Er,Cr:YSGG laser for root canal disinfection: theoretical simulation of temperature elevations in root dentin.

PubMed

Zhu, L; Tolba, M; Arola, D; Salloum, M; Meza, F

2009-07-01

Erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) lasers are currently being investigated for disinfecting the root canal system. Prior to using laser therapy, it is important to understand the temperature distribution and to assess thermal damage to the surrounding tissue. In this study, a theoretical simulation using the Pennes bioheat equation is conducted to evaluate how heat spreads from the canal surface using an Er,Cr:YSGG laser. Results of the investigation show that some of the proposed treatment protocols for killing bacteria in the deep dentin are ineffective, even for long heating durations. Based on the simulation, an alternative treatment protocol is identified that has improved effectiveness and is less likely to introduce collateral damage to the surrounding tissue. The alternative protocol uses 350 mW laser power with repeating laser tip movement to achieve bacterial disinfection in the deep dentin (800 microm lateral from the canal surface), while avoiding thermal damage to the surrounding tissue (T<47 degrees C). The alternative treatment protocol has the potential to not only achieve bacterial disinfection of deep dentin but also shorten the treatment time, thereby minimizing potential patient discomfort during laser procedures.

Effects of shielded or unshielded laser and electrohydraulic lithotripsy on rabbit bladder.

PubMed

Bhatta, K M; Rosen, D I; Flotte, T J; Dretler, S P; Nishioka, N S

1990-04-01

The pulsed dye laser and electrohydraulic lithotriptor (EHL) are both effective devices for fragmenting urinary and biliary calculi. Both fragment stones by producing a plasma-mediated shockwave. Recently, a plasma shield consisting of a hollow spring and a metal end cap has been described for use with the laser and EHL devices in an attempt to minimize tissue damage without adversely affecting stone fragmentation rates. The tissue effects produced by a pulsed dye laser and an EHL device with and without plasma shields were examined and compared using rabbit urinary bladders. If blood was present, the unshielded laser perforated the bladder wall in two pulses. However, in the absence of blood, over 100 pulses were needed for the laser to perforate the bladder. A mean of six pulses were required to perforate the bladder wall with a shielded laser. The unshielded EHL perforated the bladder wall in two pulses, whereas, the shielded EHL required a mean of 35 pulses. Microscopically, areas of exposure revealed hemorrhage and tissue ablation. We conclude that all devices examined can produce significant tissue damage when discharged directly onto bladder epithelium.

Minimally invasive microneedles for ocular drug delivery.

PubMed

Thakur Singh, Raghu Raj; Tekko, Ismaiel; McAvoy, Kathryn; McMillan, Hannah; Jones, David; Donnelly, Ryan F

2017-04-01

Anterior and posterior segment eye diseases are highly challenging to treat, due to the barrier properties and relative inaccessibility of the ocular tissues. Topical eye drops and systemically delivered treatments result in low bioavailability. Alternatively, direct injection of medication into the ocular tissues is clinically employed to overcome the barrier properties, but injections cause significant tissue damage and are associated with a number of untoward side effects and poor patient compliance. Microneedles (MNs) has been recently introduced as a minimally invasive means for localizing drug formulation within the target ocular tissues with greater precision and accuracy than the hypodermic needles. Areas covered: This review article seeks to provide an overview of a range of challenges that are often faced to achieve efficient ocular drug levels within targeted tissue(s) of the eye. It also describes the problems encountered using conventional hypodermic needle-based ocular injections for anterior and posterior segment drug delivery. It discusses research carried out in the field of MNs, to date. Expert opinion: MNs can aid in localization of drug delivery systems within the selected ocular tissue. And, hold the potential to revolutionize the way drug formulations are administered to the eye. However, the current limitations and challenges of MNs application warrant further research in this field to enable its widespread clinical application.

Optical coherence tomography monitoring of vocal fold femtosecond laser microsurgery

NASA Astrophysics Data System (ADS)

Wisweh, Henning; Merkel, Ulrich; Hüller, Ann-Kristin; Lüerßen, Kathrin; Lubatschowski, Holger

2007-07-01

Surgery of benign pathological alterations of the vocal folds results in permanent disphonia if the bounderies of the vocal fold layers are disregarded. Precise cutting with a femtosecond laser (fs-laser) combined with simultanous imaging of the layered structure enables accurate resections with respect to the layer boundaries. Earlier works demonstrated the capability of optical coherence tomography (OCT) for utilization on vocal folds. The layered structure can be imaged with a spatial resolution of 10-20μm up to a depth of 1.5mm. The performance of fs-laser cutting was analyzed on extracted porcine vocal folds with OCT monitoring. Histopathological sections of the same processed samples could be well correlated with the OCT images. With adequate laser parameters thermal effects induced only negligable damage to the processed tissue. The dimensions of the thermal necrosis were determined to be smaller than 1μm. OCT contolled fs-laser cutting of porcine vocal fold tissue in the μm range with minimal tissue damage is presented.

Bioinspired porous membranes containing polymer nanoparticles for wound healing.

PubMed

Ferreira, Ana M; Mattu, Clara; Ranzato, Elia; Ciardelli, Gianluca

2014-12-01

Skin damages covering a surface larger than 4 cm(2) require a regenerative strategy based on the use of appropriate wound dressing supports to facilitate the rapid tissue replacement and efficient self-healing of the lost or damaged tissue. In the present work, A novel biomimetic approach is proposed for the design of a therapeutic porous construct made of poly(L-lactic acid) (PLLA) fabricated by thermally induced phase separation (TIPS). Biomimicry of ECM was achieved by immobilization of type I collagen through a two-step plasma treatment for wound healing. Anti-inflammatory (indomethacin)-containing polymeric nanoparticles (nps) were loaded within the porous membranes in order to minimize undesired cell response caused by post-operative inflammation. The biological response to the scaffold was analyzed by using human keratinocytes cell cultures. In this work, a promising biomimetic construct for wound healing and soft tissue regeneration with drug-release properties was fabricated since it shows (i) proper porosity, pore size, and mechanical properties, (ii) biomimicry of ECM, and (iii) therapeutic potential. © 2014 Wiley Periodicals, Inc.

Endoscopic-assisted resection of peripheral osteoma using piezosurgery.

PubMed

Ochiai, Shigeki; Kuroyanagi, Norio; Sakuma, Hidenori; Sakuma, Hidenobu; Miyachi, Hitoshi; Shimozato, Kazuo

2013-01-01

Endoscopic-assisted surgery has gained widespread popularity as a minimally invasive procedure, particularly in the field of maxillofacial surgery. Because the surgical field around the mandibular angle is extremely narrow, the surrounding tissues may get caught in sharp rotary cutting instruments. In piezosurgery, bone tissues are selectively cut. This technique has various applications because minimal damage is caused by the rotary cutting instruments when they briefly come in contact with soft tissues. We report the case of a 33-year-old man who underwent resection of an osteoma in the region of the mandibular angle region via an intraoral approach. During surgery, the complete surgical field was within the view of the endoscope, thereby enabling the surgeon to easily resection the osteoma with the piezosurgery device. Considering that piezosurgery limits the extent of surgical invasion, this is an excellent low-risk technique that can be used in the field of maxillofacial surgery. Copyright © 2013 Elsevier Inc. All rights reserved.

Ultrashort pulse high repetition rate laser system for biological tissue processing

DOEpatents

Neev, Joseph; Da Silva, Luiz B.; Matthews, Dennis L.; Glinsky, Michael E.; Stuart, Brent C.; Perry, Michael D.; Feit, Michael D.; Rubenchik, Alexander M.

1998-01-01

A method and apparatus is disclosed for fast, efficient, precise and damage-free biological tissue removal using an ultrashort pulse duration laser system operating at high pulse repetition rates. The duration of each laser pulse is on the order of about 1 fs to less than 50 ps such that energy deposition is localized in a small depth and occurs before significant hydrodynamic motion and thermal conduction, leading to collateral damage, can take place. The depth of material removed per pulse is on the order of about 1 micrometer, and the minimal thermal and mechanical effects associated with this ablation method allows for high repetition rate operation, in the region 10 to over 1000 Hertz, which, in turn, achieves high material removal rates. The input laser energy per ablated volume of tissue is small, and the energy density required to ablate material decreases with decreasing pulse width. The ablation threshold and ablation rate are only weakly dependent on tissue type and condition, allowing for maximum flexibility of use in various biological tissue removal applications. The use of a chirped-pulse amplified Titanium-doped sapphire laser is disclosed as the source in one embodiment.

Histological Evaluation of a Chronically-implanted Electrocorticographic Electrode Grid in a Non-human Primate

PubMed Central

Degenhart, Alan D.; Eles, James; Dum, Richard; Mischel, Jessica L.; Smalianchuk, Ivan; Endler, Bridget; Ashmore, Robin C.; Tyler-Kabara, Elizabeth C.; Hatsopoulos, Nicholas G.; Wang, Wei; Batista, Aaron P.; Cui, X. Tracy

2016-01-01

Electrocorticography (ECoG), used as a neural recording modality for brain-machine interfaces (BMIs), potentially allows for field potentials to be recorded from the surface of the cerebral cortex for long durations without suffering the host-tissue reaction to the extent that it is common with intracortical microelectrodes. Though the stability of signals obtained from chronically-implanted ECoG electrodes has begun receiving attention, to date little work has characterized the effects of long-term implantation of ECoG electrodes on underlying cortical tissue. We implanted a high-density ECoG electrode grid subdurally over cortical motor areas of a Rhesus macaque for 666 days. Histological analysis revealed minimal damage to the cortex underneath the implant, though the grid itself was encapsulated in collagenous tissue. We observed macrophages and foreign body giant cells at the tissue-array interface, indicative of a stereotypical foreign body response. Despite this encapsulation, cortical modulation during reaching movements was observed more than 18 months post-implantation. These results suggest that ECoG may provide a means by which stable chronic cortical recordings can be obtained with comparatively little tissue damage, facilitating the development of clinically-viable brain-machine interface systems. PMID:27351722

Histological evaluation of a chronically-implanted electrocorticographic electrode grid in a non-human primate

NASA Astrophysics Data System (ADS)

Degenhart, Alan D.; Eles, James; Dum, Richard; Mischel, Jessica L.; Smalianchuk, Ivan; Endler, Bridget; Ashmore, Robin C.; Tyler-Kabara, Elizabeth C.; Hatsopoulos, Nicholas G.; Wang, Wei; Batista, Aaron P.; Cui, X. Tracy

2016-08-01

Objective. Electrocorticography (ECoG), used as a neural recording modality for brain-machine interfaces (BMIs), potentially allows for field potentials to be recorded from the surface of the cerebral cortex for long durations without suffering the host-tissue reaction to the extent that it is common with intracortical microelectrodes. Though the stability of signals obtained from chronically implanted ECoG electrodes has begun receiving attention, to date little work has characterized the effects of long-term implantation of ECoG electrodes on underlying cortical tissue. Approach. We implanted and recorded from a high-density ECoG electrode grid subdurally over cortical motor areas of a Rhesus macaque for 666 d. Main results. Histological analysis revealed minimal damage to the cortex underneath the implant, though the grid itself was encapsulated in collagenous tissue. We observed macrophages and foreign body giant cells at the tissue-array interface, indicative of a stereotypical foreign body response. Despite this encapsulation, cortical modulation during reaching movements was observed more than 18 months post-implantation. Significance. These results suggest that ECoG may provide a means by which stable chronic cortical recordings can be obtained with comparatively little tissue damage, facilitating the development of clinically viable BMI systems.

Ultrashort pulse high repetition rate laser system for biological tissue processing

DOEpatents

Neev, J.; Da Silva, L.B.; Matthews, D.L.; Glinsky, M.E.; Stuart, B.C.; Perry, M.D.; Feit, M.D.; Rubenchik, A.M.

1998-02-24

A method and apparatus are disclosed for fast, efficient, precise and damage-free biological tissue removal using an ultrashort pulse duration laser system operating at high pulse repetition rates. The duration of each laser pulse is on the order of about 1 fs to less than 50 ps such that energy deposition is localized in a small depth and occurs before significant hydrodynamic motion and thermal conduction, leading to collateral damage, can take place. The depth of material removed per pulse is on the order of about 1 micrometer, and the minimal thermal and mechanical effects associated with this ablation method allows for high repetition rate operation, in the region 10 to over 1000 Hertz, which, in turn, achieves high material removal rates. The input laser energy per ablated volume of tissue is small, and the energy density required to ablate material decreases with decreasing pulse width. The ablation threshold and ablation rate are only weakly dependent on tissue type and condition, allowing for maximum flexibility of use in various biological tissue removal applications. The use of a chirped-pulse amplified Titanium-doped sapphire laser is disclosed as the source in one embodiment. 8 figs.

Examination of Physiological Function and Biochemical Disorders in a Rat Model of Prolonged Asphyxia-Induced Cardiac Arrest followed by Cardio Pulmonary Bypass Resuscitation

PubMed Central

Kim, Junhwan; Yin, Tai; Yin, Ming; Zhang, Wei; Shinozaki, Koichiro; Selak, Mary A.; Pappan, Kirk L.; Lampe, Joshua W.; Becker, Lance B.

2014-01-01

Background Cardiac arrest induces whole body ischemia, which causes damage to multiple organs particularly the heart and the brain. There is clinical and preclinical evidence that neurological injury is responsible for high mortality and morbidity of patients even after successful cardiopulmonary resuscitation. A better understanding of the metabolic alterations in the brain during ischemia will enable the development of better targeted resuscitation protocols that repair the ischemic damage and minimize the additional damage caused by reperfusion. Method A validated whole body model of rodent arrest followed by resuscitation was utilized; animals were randomized into three groups: control, 30 minute asphyxial arrest, or 30 minutes asphyxial arrest followed by 60 min cardiopulmonary bypass (CPB) resuscitation. Blood gases and hemodynamics were monitored during the procedures. An untargeted metabolic survey of heart and brain tissues following cardiac arrest and after CPB resuscitation was conducted to better define the alterations associated with each condition. Results After 30 min cardiac arrest and 60 min CPB, the rats exhibited no observable brain function and weakened heart function in a physiological assessment. Heart and brain tissues harvested following 30 min ischemia had significant changes in the concentration of metabolites in lipid and carbohydrate metabolism. In addition, the brain had increased lysophospholipid content. CPB resuscitation significantly normalized metabolite concentrations in the heart tissue, but not in the brain tissue. Conclusion The observation that metabolic alterations are seen primarily during cardiac arrest suggests that the events of ischemia are the major cause of neurological damage in our rat model of asphyxia-CPB resuscitation. Impaired glycolysis and increased lysophospholipids observed only in the brain suggest that altered energy metabolism and phospholipid degradation may be a central mechanism in unresuscitatable brain damage. PMID:25383962

Examination of physiological function and biochemical disorders in a rat model of prolonged asphyxia-induced cardiac arrest followed by cardio pulmonary bypass resuscitation.

PubMed

Kim, Junhwan; Yin, Tai; Yin, Ming; Zhang, Wei; Shinozaki, Koichiro; Selak, Mary A; Pappan, Kirk L; Lampe, Joshua W; Becker, Lance B

2014-01-01

Cardiac arrest induces whole body ischemia, which causes damage to multiple organs particularly the heart and the brain. There is clinical and preclinical evidence that neurological injury is responsible for high mortality and morbidity of patients even after successful cardiopulmonary resuscitation. A better understanding of the metabolic alterations in the brain during ischemia will enable the development of better targeted resuscitation protocols that repair the ischemic damage and minimize the additional damage caused by reperfusion. A validated whole body model of rodent arrest followed by resuscitation was utilized; animals were randomized into three groups: control, 30 minute asphyxial arrest, or 30 minutes asphyxial arrest followed by 60 min cardiopulmonary bypass (CPB) resuscitation. Blood gases and hemodynamics were monitored during the procedures. An untargeted metabolic survey of heart and brain tissues following cardiac arrest and after CPB resuscitation was conducted to better define the alterations associated with each condition. After 30 min cardiac arrest and 60 min CPB, the rats exhibited no observable brain function and weakened heart function in a physiological assessment. Heart and brain tissues harvested following 30 min ischemia had significant changes in the concentration of metabolites in lipid and carbohydrate metabolism. In addition, the brain had increased lysophospholipid content. CPB resuscitation significantly normalized metabolite concentrations in the heart tissue, but not in the brain tissue. The observation that metabolic alterations are seen primarily during cardiac arrest suggests that the events of ischemia are the major cause of neurological damage in our rat model of asphyxia-CPB resuscitation. Impaired glycolysis and increased lysophospholipids observed only in the brain suggest that altered energy metabolism and phospholipid degradation may be a central mechanism in unresuscitatable brain damage.

Myocardial regeneration potential of adipose tissue-derived stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bai, Xiaowen, E-mail: baixw01@yahoo.com; Alt, Eckhard, E-mail: ealt@mdanderson.org

Research highlights: {yields} Various tissue resident stem cells are receiving tremendous attention from basic scientists and clinicians and hold great promise for myocardial regeneration. {yields} For practical reasons, human adipose tissue-derived stem cells are attractive stem cells for future clinical application in repairing damaged myocardium. {yields} This review summarizes the characteristics of cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential and the, underlying mechanisms, and safety issues. -- Abstract: Various tissue resident stem cells are receiving attention from basic scientists and clinicians as they hold promise for myocardial regeneration. For practical reasons, adipose tissue-derivedmore » stem cells (ASCs) are attractive cells for clinical application in repairing damaged myocardium based on the following advantages: abundant adipose tissue in most patients and easy accessibility with minimally invasive lipoaspiration procedure. Several recent studies have demonstrated that both cultured and freshly isolated ASCs could improve cardiac function in animal model of myocardial infarction. The mechanisms underlying the beneficial effect of ASCs on myocardial regeneration are not fully understood. Growing evidence indicates that transplantation of ASCs improve cardiac function via the differentiation into cardiomyocytes and vascular cells, and through paracrine pathways. Paracrine factors secreted by injected ASCs enhance angiogenesis, reduce cell apoptosis rates, and promote neuron sprouts in damaged myocardium. In addition, Injection of ASCs increases electrical stability of the injured heart. Furthermore, there are no reported cases of arrhythmia or tumorigenesis in any studies regarding myocardial regeneration with ASCs. This review summarizes the characteristics of both cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential, and the underlying mechanisms for beneficial effect on cardiac function, and safety issues.« less

Radiofrequency Thermal Ablation Heat Energy Transfer in an Ex-Vivo Model.

PubMed

Thakur, Shivani; Lavito, Sandi; Grobner, Elizabeth; Grobner, Mark

2017-12-01

Little work has been done to consider the temperature changes and energy transfer that occur in the tissue outside the vein with ultrasound-guided vein ablation therapy. In this experiment, a Ex-Vivo model of the human calf was used to analyze heat transfer and energy degradation in tissue surrounding the vein during endovascular radiofrequency ablation (RFA). A clinical vein ablation protocol was used to determine the tissue temperature distribution in 10 per cent agar gel. Heat energy from the radiofrequency catheter was measured for 140 seconds at fixed points by four thermometer probes placed equidistant radially at 0.0025, 0.005, and 0.01 m away from the RFA catheter. The temperature rose 1.5°C at 0.0025 m, 0.6°C at 0.005 m, and 0.0°C at 0.01 m from the RFA catheter. There was a clinically insignificant heat transfer at the distances evaluated, 1.4 ± 0.2 J/s at 0.0025 m, 0.7 ± 0.3 J/s at 0.0050 m, and 0.3 ± 0.0 J/s at 0.01 m. Heat degradation occurred rapidly: 4.5 ± 0.5 J (at 0.0025 m), 4.0 ± 1.6 J (at 0.0050 m), and 3.9 ± 3.6 J (at 0.01 m). Tumescent anesthesia injected one centimeter around the vein would act as a heat sink to absorb the energy transferred outside the vein to minimize tissue and nerve damage and will help phlebologists strategize options for minimizing damage.

Optical clearing of vaginal tissues, ex vivo, for minimally invasive laser treatment of female stress urinary incontinence

PubMed Central

Chang, Chun-Hung; Myers, Erinn M.; Kennelly, Michael J.; Fried, Nathaniel M.

2017-01-01

Abstract. Near-infrared laser energy in conjunction with applied tissue cooling is being investigated for thermal remodeling of the endopelvic fascia during minimally invasive treatment of female stress urinary incontinence. Previous computer simulations of light transport, heat transfer, and tissue thermal damage have shown that a transvaginal approach is more feasible than a transurethral approach. However, results were suboptimal, and some undesirable thermal insult to the vaginal wall was still predicted. This study uses experiments and computer simulations to explore whether application of an optical clearing agent (OCA) can further improve optical penetration depth and completely preserve the vaginal wall during subsurface treatment of the endopelvic fascia. Several different mixtures of OCA’s were tested, and 100% glycerol was found to be the optimal agent. Optical transmission studies, optical coherence tomography, reflection spectroscopy, and computer simulations [including Monte Carlo (MC) light transport, heat transfer, and Arrhenius integral model of thermal damage] using glycerol were performed. The OCA produced a 61% increase in optical transmission through porcine vaginal wall at 37°C after 30 min. The MC model showed improved energy deposition in endopelvic fascia using glycerol. Without OCA, 62%, 37%, and 1% of energy was deposited in vaginal wall, endopelvic fascia, and urethral wall, respectively, compared with 50%, 49%, and 1% using OCA. Use of OCA also resulted in 0.5-mm increase in treatment depth, allowing potential thermal tissue remodeling at a depth of 3 mm with complete preservation of the vaginal wall. PMID:28301637

CT guided interstitial therapy of pancreatic carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haaga, J.R.; Owens, D.B.; Kellermeyer, R.W.

1987-11-01

We describe the use of percutaneous CT guidance for localization and placement of /sup 192/Ir sources into a patient with pancreatic carcinoma. We have shown the feasibility of this procedure and the lack of complications which are probably due to minimal damage to tissue involved. Computed tomography is ideally suited for percutaneous implantation because it provides the most accurate method for needle placement within the abdomen.

A PDMS-Based Conical-Well Microelectrode Array for Surface Stimulation and Recording of Neural Tissues

PubMed Central

Guo, Liang; Meacham, Kathleen W.; Hochman, Shawn

2012-01-01

A method for fabricating polydimethylsiloxane (PDMS)-based microelectrode arrays (MEAs) featuring novel conical-well microelectrodes is described. The fabrication technique is reliable and efficient, and facilitates controllability over both the depth and the slope of the conical wells. Because of the high PDMS elasticity (as compared to other MEA substrate materials), this type of compliant MEA is promising for acute and chronic implantation in applications that benefit from conformable device contact with biological tissue surfaces and from minimal tissue damage. The primary advantage of the conical-well microelectrodes—when compared to planar electrodes—is that they provide an improved contact on tissue surface, which potentially provides isolation of the electrode microenvironment for better electrical interfacing. The raised wells increase the uniformity of current density distributions at both the electrode and tissue surfaces, and they also protect the electrode material from mechanical damage (e.g. from rubbing against the tissue). Using this technique, electrodes have been fabricated with diameters as small as 10µm and arrays have been fabricated with center-to-center electrode spacings of 60µm. Experimental results are presented, describing electrode-profile characterization, electrode-impedance measurement, and MEA-performance evaluation on fiber bundle recruitment in spinal cord white matter. PMID:20550983

Gender differences in cocaine pharmacokinetics in CF-1 mice.

PubMed

Visalli, Thomas; Turkall, Rita; Abdel-Rahman, Mohamed S

2005-01-15

Hepatocellular damage is thought to occur as a result of cytochrome P450-mediated oxidation of cocaine to norcocaine (NC), a precursor of the hepatotoxic nitrosonium ion. However, this damage occurs only in male mice, with females exhibiting minimal biochemical and histological signs of hepatocellular stress. The objective of this study was to determine the plasma time course and tissue disposition of cocaine and its metabolites to further investigate the role that metabolism may play in the gender difference observed. Male and female CF-1 mice were orally administered 20mg/kg cocaine hydrochloride once daily for 7 days. Blood samples were withdrawn at various time points post-injection and analyzed for cocaine and its metabolites benzoylecgonine (BE), norcocaine, ecgonine methyl ester (EME), and ecgonine (E). In addition, tissue concentrations of cocaine and its metabolites were determined in liver, heart, brain, and kidney tissue. The results demonstrated that the plasma elimination half-life of cocaine is nearly three times longer in males versus females. Non-hepatotoxic hydrolysis metabolites BE, EME, and E were higher in female tissues while norcocaine was detected in tissues of male animals only. This study revealed that differences in cocaine pharmacokinetics and the resultant differences in the biodisposition of cocaine and its metabolites in tissues contribute to the mechanism of gender difference seen in cocaine hepatotoxicity.

Antibrowning and antimicrobial properties of sodium acid sulfate in apple slices.

PubMed

Fan, Xuetong; Sokorai, Kimberly J B; Liao, Ching-Hsing; Cooke, Peter; Zhang, Howard Q

2009-01-01

There are few available compounds that can both control browning and enhance microbial safety of fresh-cut fruits. In the present study, the antibrowning ability of sodium acid sulfate (SAS) on "Granny Smith" apple slices was first investigated in terms of optimum concentration and treatment time. In a separate experiment, the apple slices were treated with water or 3% of SAS, calcium ascorbate, citric acid, or acidified calcium sulfate for 5 min. Total plate count, color, firmness, and tissue damage were assessed during a 21-d storage at 4 degrees C. Results showed that the efficacy of SAS in inhibiting browning of apple slices increased with increasing concentration. A minimum 3% of SAS was needed to achieve 14 d of shelf life. Firmness was not significantly affected by SAS at 3% or lower concentrations. Antibrowning potential of SAS was similar for all treatment times ranging from 2 to 10 min. However, SAS caused some skin discoloration of apple slices. When cut surface of apple slices were stained with a fluorescein diacetate solution, tissue damage could be observed under a microscope even though visual damage was not evident. Among the antibrowning agents tested, SAS was the most effective in inhibiting browning and microbial growth for the first 14 d. Total plate count of samples treated with 3% SAS was significantly lower than those treated with calcium ascorbate, a commonly used antibrowning agent. Our results suggested that it is possible to use SAS to control browning while inhibiting the growth of microorganisms on the apple slices if the skin damage can be minimized. Practical Application: Fresh-cut apples have emerged as one of the popular products in restaurants, schools, and food service establishments as more consumers demand fresh, convenient, and nutritious foods. Processing of fresh-cut apples induces mechanical damage to the fruit and exposes apple tissue to air, resulting in the development of undesirable tissue browning. The fresh-cut industry currently uses antibrowning agents to prevent discoloration. However, the antibrowning solutions can become contaminated with human pathogens such as Listeria monocytogenes, and washing of apple slices with the contaminated solutions can result in the transfer of pathogens to the product. It would be ideal if an antibrowning compound prevented the proliferation of human pathogens in solutions and minimized the growth of pathogens during storage. The study was conducted to investigate antibrowning and antimicrobial properties of sodium acid sulfate (SAS) in comparison with other common antibrowning agents on Granny Smith apples. Results showed that among the antimicrobial agents we tested, SAS was the most effective in inhibiting browning and microbial growth for 14 d at 4 degrees C. However, SAS caused some skin discoloration of apple slices. Overall, SAS can potentially be used to inhibit tissue browning while reducing the microbial growth on apple slices. The information is useful for the fresh-cut produce industry to enhance microbial safety of fresh-cut apples while minimizing browning, thus increasing the consumption of the health benefiting fresh fruit.

Deep tissue single cell MSC ablation using a fiber laser source to evaluate therapeutic potential in osteogenesis imperfecta

NASA Astrophysics Data System (ADS)

Tehrani, Kayvan F.; Pendleton, Emily G.; Lin, Charles P.; Mortensen, Luke J.

2016-04-01

Osteogenesis imperfecta (OI) is a currently uncurable disease where a mutation in collagen type I yields brittle bones. One potential therapy is transplantation of mesenchymal stem cells (MSCs), but controlling and enhancing transplanted cell survival has proven challenging. Therefore, we use a 2- photon imaging system to study individual transplanted cells in the living bone marrow. We ablated cells deep in the bone marrow and observed minimal collateral damage to surrounding tissue. Future work will evaluate the local impact of transplanted MSCs on bone deposition in vivo.

Evaluation of transurethral and transperineal tin ethyl etiopurpurin-photodynamic therapy on the canine prostate one week after drug injection

NASA Astrophysics Data System (ADS)

Selman, Steven H.; Keck, Rick W.; Kondo, Sandy; Albrecht, Detlef

1999-06-01

We have been investigating the potential applicability of photodynamic therapy for the treatment of benign and malignant disease of the prostate. Both transurethral and transperineal approaches to the delivery of light to the tin ethyl etiopurpurin sensitized canine prostate have been studied. Pharmacologic studies were performed and suggested that delaying light treatment for 7 days after drug administration would maximize the desired effect on the targeted prostatic tissue while minimizing the damage to surrounding bladder and rectum. A total of 12 dogs were treated with transurethral light alone (n=6) or the combination of transurethral light and transperineal light one week after tin ethyl etiopurpurin administration. (Previous studies have shown that light alone has no effect on prostate size or histology.) Animals were euthanized 48 hours and 3 weeks after completion of treatment (drug, 1mg/kg day 0, light [400mw/750sec]day 7). Tissue response was determined by gross and microscopic examination. Additionally, pre- and post- treatment transrectal ultrasounds were compared to assess changes in prostate volume and tissue echogenicity. The combination of transurethral and transperineal light results in extensive destruction of glandular epithelium with minimal damage to surrounding structures. Prostate volumes decreased by an average of 52%. Untreated areas were found to lie greater than 0.5 cm from the light diffuser. These studies have encouraged us to continue to investigate this modality as a technique for total ablation of prostatic glandular epithelium.

[Injuries and fatalities caused by gas-/warning weapons].

PubMed

Maxeiner, H; Schneider, V

1989-01-01

Detailed report of 5 cases of violation with gas or warning firearms, 3 of them lethal. In one case a modified weapon (elongated barrel) and steel bullets were used, resulting in shot of the head with retained missile and lethal bleeding. In the other cases, regular weapons (8 or 9 mm cartridges) were used for contact shots; violation occurred only by the effect of powder gases. One of these cases was a suizide (lethal temporal gunshot), in the other cases shots by another person: a) shot against the arm with large soft-tissue damage (survived); b) and c) shot against the neck with exceeding rupture of the soft tissues, minimal damage of the neck arteries and in one cases bilateral tears of the hypopharynx. In this case a delayed death after primarily well operated injury occurred after 12 days by bleeding into the airways from ruptured external carotid artery.

Repairable-conditionally repairable damage model based on dual Poisson processes.

PubMed

Lind, B K; Persson, L M; Edgren, M R; Hedlöf, I; Brahme, A

2003-09-01

The advent of intensity-modulated radiation therapy makes it increasingly important to model the response accurately when large volumes of normal tissues are irradiated by controlled graded dose distributions aimed at maximizing tumor cure and minimizing normal tissue toxicity. The cell survival model proposed here is very useful and flexible for accurate description of the response of healthy tissues as well as tumors in classical and truly radiobiologically optimized radiation therapy. The repairable-conditionally repairable (RCR) model distinguishes between two different types of damage, namely the potentially repairable, which may also be lethal, i.e. if unrepaired or misrepaired, and the conditionally repairable, which may be repaired or may lead to apoptosis if it has not been repaired correctly. When potentially repairable damage is being repaired, for example by nonhomologous end joining, conditionally repairable damage may require in addition a high-fidelity correction by homologous repair. The induction of both types of damage is assumed to be described by Poisson statistics. The resultant cell survival expression has the unique ability to fit most experimental data well at low doses (the initial hypersensitive range), intermediate doses (on the shoulder of the survival curve), and high doses (on the quasi-exponential region of the survival curve). The complete Poisson expression can be approximated well by a simple bi-exponential cell survival expression, S(D) = e(-aD) + bDe(-cD), where the first term describes the survival of undamaged cells and the last term represents survival after complete repair of sublethal damage. The bi-exponential expression makes it easy to derive D(0), D(q), n and alpha, beta values to facilitate comparison with classical cell survival models.

Rapid and Selective Removal of Composite From Tooth Surfaces With a 9.3 μm CO2 Laser Using Spectral Feedback

PubMed Central

Chan, Kenneth H.; Hirasuna, Krista; Fried, Daniel

2015-01-01

Objective Dental composite restorative materials are color matched to the tooth and are difficult to remove by mechanical means without excessive removal or damage to peripheral enamel and dentin. Lasers are ideally suited for selective ablation to minimize healthy tissue loss when replacing existing restorations, sealants, or removing composite adhesives such as residual composite left after debonding orthodontic brackets. Methods In this study, a carbon dioxide laser operating at 9.3-μm with a pulse duration of 10–20-microsecond and a pulse repetition rate of ~200 Hz was integrated with a galvanometer based scanner and used to selectively remove composite from tooth surfaces. Spectra of the plume emission were acquired after each laser pulse and used to differentiate between the ablation of dental enamel or composite. Microthermocouples were used to monitor the temperature rise in the pulp chamber during composite removal. The composite was placed on tooth buccal and occlusal surfaces and the carbon dioxide laser beam was scanned across the surface to selectively remove the composite without excessive damage to the underlying sound enamel. The residual composite and the damage to the underlying enamel was evaluated using optical microscopy. Results The laser was able to rapidly remove composite from tooth buccal and occlusal surfaces with minimal damage to the underlying sound enamel and without excessive heat accumulation in the tooth. Conclusion This study demonstrated that composite can be selectively removed from tooth surfaces at clinically relevant rates using a CO2 laser operating at 9.3-μm with high pulse repetition rates with minimal heat deposition and damage to the underlying enamel. PMID:21956630

Rapid and selective removal of composite from tooth surfaces with a 9.3 µm CO2 laser using spectral feedback.

PubMed

Chan, Kenneth H; Hirasuna, Krista; Fried, Daniel

2011-09-01

Dental composite restorative materials are color matched to the tooth and are difficult to remove by mechanical means without excessive removal or damage to peripheral enamel and dentin. Lasers are ideally suited for selective ablation to minimize healthy tissue loss when replacing existing restorations, sealants, or removing composite adhesives such as residual composite left after debonding orthodontic brackets. In this study, a carbon dioxide laser operating at 9.3-µm with a pulse duration of 10-20-microsecond and a pulse repetition rate of ∼200 Hz was integrated with a galvanometer based scanner and used to selectively remove composite from tooth surfaces. Spectra of the plume emission were acquired after each laser pulse and used to differentiate between the ablation of dental enamel or composite. Microthermocouples were used to monitor the temperature rise in the pulp chamber during composite removal. The composite was placed on tooth buccal and occlusal surfaces and the carbon dioxide laser beam was scanned across the surface to selectively remove the composite without excessive damage to the underlying sound enamel. The residual composite and the damage to the underlying enamel was evaluated using optical microscopy. The laser was able to rapidly remove composite from tooth buccal and occlusal surfaces with minimal damage to the underlying sound enamel and without excessive heat accumulation in the tooth. This study demonstrated that composite can be selectively removed from tooth surfaces at clinically relevant rates using a CO(2) laser operating at 9.3-µm with high pulse repetition rates with minimal heat deposition and damage to the underlying enamel. Copyright © 2011 Wiley-Liss, Inc.

A novel minimal invasive mouse model of extracorporeal circulation.

PubMed

Luo, Shuhua; Tang, Menglin; Du, Lei; Gong, Lina; Xu, Jin; Chen, Youwen; Wang, Yabo; Lin, Ke; An, Qi

2015-01-01

Extracorporeal circulation (ECC) is necessary for conventional cardiac surgery and life support, but it often triggers systemic inflammation that can significantly damage tissue. Studies of ECC have been limited to large animals because of the complexity of the surgical procedures involved, which has hampered detailed understanding of ECC-induced injury. Here we describe a minimally invasive mouse model of ECC that may allow more extensive mechanistic studies. The right carotid artery and external jugular vein of anesthetized adult male C57BL/6 mice were cannulated to allow blood flow through a 1/32-inch external tube. All animals (n = 20) survived 30 min ECC and subsequent 60 min observation. Blood analysis after ECC showed significant increases in levels of tumor necrosis factor α, interleukin-6, and neutrophil elastase in plasma, lung, and renal tissues, as well as increases in plasma creatinine and cystatin C and decreases in the oxygenation index. Histopathology showed that ECC induced the expected lung inflammation, which included alveolar congestion, hemorrhage, neutrophil infiltration, and alveolar wall thickening; in renal tissue, ECC induced intracytoplasmic vacuolization, acute tubular necrosis, and epithelial swelling. Our results suggest that this novel, minimally invasive mouse model can recapitulate many of the clinical features of ECC-induced systemic inflammatory response and organ injury.

A Novel Minimal Invasive Mouse Model of Extracorporeal Circulation

PubMed Central

Luo, Shuhua; Tang, Menglin; Du, Lei; Gong, Lina; Xu, Jin; Chen, Youwen; Wang, Yabo; Lin, Ke; An, Qi

2015-01-01

Extracorporeal circulation (ECC) is necessary for conventional cardiac surgery and life support, but it often triggers systemic inflammation that can significantly damage tissue. Studies of ECC have been limited to large animals because of the complexity of the surgical procedures involved, which has hampered detailed understanding of ECC-induced injury. Here we describe a minimally invasive mouse model of ECC that may allow more extensive mechanistic studies. The right carotid artery and external jugular vein of anesthetized adult male C57BL/6 mice were cannulated to allow blood flow through a 1/32-inch external tube. All animals (n = 20) survived 30 min ECC and subsequent 60 min observation. Blood analysis after ECC showed significant increases in levels of tumor necrosis factor α, interleukin-6, and neutrophil elastase in plasma, lung, and renal tissues, as well as increases in plasma creatinine and cystatin C and decreases in the oxygenation index. Histopathology showed that ECC induced the expected lung inflammation, which included alveolar congestion, hemorrhage, neutrophil infiltration, and alveolar wall thickening; in renal tissue, ECC induced intracytoplasmic vacuolization, acute tubular necrosis, and epithelial swelling. Our results suggest that this novel, minimally invasive mouse model can recapitulate many of the clinical features of ECC-induced systemic inflammatory response and organ injury. PMID:25705092

Image-Guided Abdominal Surgery and Therapy Delivery

PubMed Central

Galloway, Robert L.; Herrell, S. Duke; Miga, Michael I.

2013-01-01

Image-Guided Surgery has become the standard of care in intracranial neurosurgery providing more exact resections while minimizing damage to healthy tissue. Moving that process to abdominal organs presents additional challenges in the form of image segmentation, image to physical space registration, organ motion and deformation. In this paper, we present methodologies and results for addressing these challenges in two specific organs: the liver and the kidney. PMID:25077012

Repetition rate dependency of low-density plasma effects during femtosecond-laser-based surgery of biological tissue

NASA Astrophysics Data System (ADS)

Kuetemeyer, K.; Baumgart, J.; Lubatschowski, H.; Heisterkamp, A.

2009-11-01

Femtosecond laser based nanosurgery of biological tissue is usually done in two different regimes. Depending on the application, low kHz repetition rates above the optical breakdown threshold or high MHz repetition rates in the low-density plasma regime are used. In contrast to the well understood optical breakdown, mechanisms leading to dissection below this threshold are not well known due to the complexity of chemical effects with high numbers of interacting molecules. Furthermore, the laser repetition rate may influence their efficiency. In this paper, we present our study on low-density plasma effects in biological tissue depending on repetition rate by static exposure of porcine corneal stroma to femtosecond pulses. We observed a continuous increase of the laser-induced damage with decreasing repetition rate over two orders of magnitude at constant numbers of applied laser pulses or constant laser pulse energies. Therefore, low repetition rates in the kHz regime are advantageous to minimize the total delivered energy to biological tissue during femtosecond laser irradiation. However, due to frequent excessive damage in this regime directly above the threshold, MHz repetition rates are preferable to create nanometer-sized cuts in the low-density plasma regime.

Lizard tail regeneration as an instructive model of enhanced healing capabilities in an adult amniote.

PubMed

Lozito, Thomas P; Tuan, Rocky S

2017-03-01

The ability to regenerate damaged or lost tissues has remained the lofty goal of regenerative medicine. Unfortunately, humans, like most mammals, suffer from very minimal natural regenerative capabilities. Certain non-mammalian animal species, however, are not so limited in their healing capabilities, and several have attracted the attention of researchers hoping to recreate enhanced healing responses in humans. This review focuses on one such animal group with remarkable regenerative abilities, the lizards. As the closest relatives of mammals that exhibit enhanced regenerative abilities as adults, lizards potentially represent the most relevant model for direct comparison and subsequent improvement of mammalian healing. Lizards are able to regenerate amputated tails and exhibit adaptations that both limit tissue damage in response to injury and initiate coordinated regenerative responses. This review summarizes the salient aspects of lizard tail regeneration as they relate to the overall regenerative process and also presents the relevant information pertaining to regrowth of specific tissues, including skeletal, muscular, nervous, and vascular tissues. The goal of this review is to introduce the topic of lizard tail regeneration to new audiences with the hope of expanding the knowledge base of this underutilized but potentially powerful model organism.

Factors Affecting the Use of Human Tissues in Biomedical Research: Implications in the Design and Operation of a Biorepository.

PubMed

Atherton, Daniel S; Sexton, Katherine C; Otali, Dennis; Bell, Walter C; Grizzle, William E

2016-01-01

The availability of high-quality human tissues is necessary to advance medical research. Although there are inherent and induced limitations on the use of human tissues in research, biorepositories play critical roles in minimizing the effects of such limitations. Specifically, the optimal utilization of tissues in research requires tissues to be diagnosed accurately, and the actual specimens provided to investigators must be carefully described (i.e., there must be quality control of each aliquot of the tissue provided for research, including a description of any damage to tissues). Tissues also should be collected, processed, stored, and distributed (i.e., handled) uniformly under a rigorous quality management system (QMS). Frequently, tissues are distributed to investigators by tissue banks which have collected, processed, and stored them by standard operating procedures (SOPs). Alternatively, tissues for research may be handled via SOPs that are modified to the specific requirements of investigators (i.e., using a prospective biorepository model). The primary goal of any type of biorepository should be to ensure its specimens are of high quality and are utilized appropriately in research; however, approaches may vary based on the tissues available and requested. For example, extraction of specific molecules (e.g., microRNA) to study molecular characteristics of a tissue may require less clinical annotation than tissues that are utilized to identify how the molecular expression might be used to clarify a clinical outcome of a disease or the response to a specific therapy. This review focuses on the limitations of the use of tissues in research and how the design and operations of a tissue biorepository can minimize some of these limitations.

Thermoelectric needle probe for temperature measurements in biological materials.

PubMed

Korn, U; Rav-Noy, Z; Shtrikman, S; Zafrir, M

1980-04-01

In certain biological and medical applications it is important to measure and follow temperature changes inside a body or tissue. Any probe inserted into a tissue causes damage to tissue and distortion to the initial temperature distribution. To minimize this interference, a fine probe is needed. Thus, thin film technology is advantageous and was utilized by us to produce sensitive probes for these applications. The resulting probe is a small thermocouple at the tip of a thin needle (acupuncture stainless steel needle, approximately 0.26 mm in diameter and length in the range 5-10 cm was used). The junction was produced at the needle's tip by coating the needle with thin layers of insulating and thermoelectric materials. The first layer is an insulating one and is composed of polyacrylonitrile (PAN) and polymide produced by plasma polymerization and dip-coating respectively. This layer covers all the needle except the tip. The second layer is a vacuum deposited thermoelectric thin layer of Bi-5% Sb alloy coating also the tip. The third layer is for insulation and protection and is composed of PAN and polyimide. In this arrangement the junction is at the needle's tip, the needle is one conductor, the thermoelectric layer is the other and they are isolated by the plastic layer. The probe is handy and mechanically sturdy. The sensitivity is typically 77 microV/degrees C at room temperature and is constant to within 2% up to 90 degrees C. The response is fast (less than 1 sec) the noise is small, (less than 0.05 degrees C) and because of the small dimension, damage to tissue and disturbance to the measured temperature field are minimal.

CTE:YAG laser applications in dentistry

NASA Astrophysics Data System (ADS)

Shori, Ramesh K.; Fried, Daniel; Featherstone, John D. B.; Kokta, Milan R.; Duhn, Clifford W.

1998-04-01

The suitability of CTE:YAG laser radiation was investigated for caries preventive laser treatments and caries ablation. Although, CTE:YAG laser radiation at 2.69 micrometer is less highly absorbed by dental hard tissues than other erbium laser wavelengths, namely 2.79 and 2.94 micrometer, it can readily be transmitted through a conventional low hydroxyl fiber with minimal loss. These studies show that reasonable ablation rates and efficiencies are obtainable with both free running (200 microseconds) and Q-switched (100 ns) laser pulses on both dentin and enamel with the application of a relatively thick layer of water to the tissue surface. The water served to remove tissue char and debris from the ablation site leaving a clean crater. However, mechanical forces produced during the energetic ablative process resulted in peripheral mechanical damage to the tissue. Surface dissolution studies on enamel indicated that CTE:YAG radiation inhibited surface dissolution by organic acid by 60 - 70% compared to unirradiated controls, albeit, at fluences an order of magnitude higher than those required for CO2 laser radiation. This layer system may be suitable for dental hard tissue applications if mechanical damage can be mitigated. This work was supported by NIH/NIDR Grants R29DE12091 and R01DE09958.

Avoiding Complications in Bone and Soft Tissue Ablation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurup, A. Nicholas, E-mail: kurup.anil@mayo.edu; Schmit, Grant D., E-mail: schmit.grant@mayo.edu; Morris, Jonathan M., E-mail: morris.jonathan@mayo.edu

As with percutaneous ablation of tumors in the liver, lungs, and kidneys, ablation of bone and non-visceral soft tissue tumors carries risk, primarily from collateral damage to vital structures in proximity to the target tumor. Certain risks are of particular interest when ablating bone and non-visceral soft tissue tumors, namely neural or skin injury, bowel injury, fracture, and gas embolism from damaged applicators. Ablation of large volume tumors also carries special risk. Many techniques may be employed by the interventional radiologist to minimize complications when treating tumors in the musculoskeletal system. These methods include those to depict, displace, or monitormore » critical structures. Thus, measures to provide thermoprotection may be active, such as careful ablation applicator placement and use of various displacement techniques, as well as passive, including employment of direct temperature, radiographic, or neurophysiologic monitoring techniques. Cementoplasty should be considered in certain skeletal locations at risk of fracture. Patients treated with large volume tumors should be monitored for renal dysfunction and properly hydrated. Finally, ablation applicators should be cautiously placed in the constrained environment of intact bone.« less

Retrograde nail for tibiotalocalcaneal arthrodesis as a limb salvage procedure for open distal tibia and talus fractures with severe bone loss.

PubMed

Ochman, Sabine; Evers, Julia; Raschke, Michael J; Vordemvenne, Thomas

2012-01-01

The treatment of complex fractures of the distal tibia, ankle, and talus with soft tissue damage, bone loss, and nonreconstructable joints for which the optimal timing for reduction and fixation has been missed is challenging. In such cases primary arthrodesis might be a treatment option. We report a series of multi-injured patients with severe soft tissue damage and bone loss, who were treated with a retrograde tibiotalocalcaneal arthrodesis nail as a minimally invasive treatment option for limb salvage. After a median follow-up of 5.4 years, all patients returned to their former profession. The ankle and bone fusion was complete, with moderate functional results and quality of life. Calcaneotibial arthrodesis using a retrograde nail is a good treatment option for nonreconstructable fractures of the ankle joint with severe bone loss and poor soft tissue quality in selected patients with multiple injuries, in particular, those involving both lower extremities, as a salvage procedure. Copyright © 2012 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

In-vivo optical imaging of hsp70 expression to assess collateral tissue damage associated with infrared laser ablation of skin

PubMed Central

Wilmink, Gerald J.; Opalenik, Susan R.; Beckham, Joshua T.; Mackanos, Mark A.; Nanney, Lillian B.; Contag, Christopher H.; Davidson, Jeffrey M.; Jansen, E. Duco

2013-01-01

Laser surgical ablation is achieved by selecting laser parameters that remove confined volumes of target tissue and cause minimal collateral damage. Previous studies have measured the effects of wavelength on ablation, but neglected to measure the cellular impact of ablation on cells outside the lethal zone. In this study, we use optical imaging in addition to conventional assessment techniques to evaluate lethal and sublethal collateral damage after ablative surgery with a free-electron laser (FEL). Heat shock protein (HSP) expression is used as a sensitive quantitative marker of sublethal damage in a transgenic mouse strain, with the hsp70 promoter driving luciferase and green fluorescent protein (GFP) expression (hsp70A1-L2G). To examine the wavelength dependence in the mid-IR, laser surgery is conducted on the hsp70A1-L2G mouse using wavelengths targeting water (OH stretch mode, 2.94 μm), protein (amide-II band, 6.45 μm), and both water and protein (amide-I band, 6.10 μm). For all wavelengths tested, the magnitude of hsp70 expression is dose-dependent and maximal 5 to 12 h after surgery. Tissues treated at 6.45 μm have approximately 4× higher hsp70 expression than 6.10 μm. Histology shows that under comparable fluences, tissue injury at the 2.94-μm wavelength was 2× and 3× deeper than 6.45 and 6.10 μm, respectively. The 6.10-μm wavelength generates the least amount of epidermal hyperplasia. Taken together, this data suggests that the 6.10-μm wavelength is a superior wavelength for laser ablation of skin. PMID:19021444

Morphological and chemical information in fresh and vitrified ovarian tissues revealed by X-ray Microscopy and Fluorescence: observational study

NASA Astrophysics Data System (ADS)

Pascolo, L.; Venturin, I.; Gianoncelli, A.; Salomé, M.; Altissimo, M.; Bedolla, D. E.; Giolo, E.; Martinelli, M.; Luppi, S.; Romano, F.; Zweyer, M.; Ricci, G.

2018-06-01

Many clinical circumstances impose the necessity of collection and prolonged storage of gametes and/or ovarian tissue in order to preserve the reproduction potential of subjects. This is particularly appropriate in the case of young women and pre-pubertal girls undergoing chemotherapeutic treatments. The success of later assisted fertilization will depend on the suitable cooling protocols minimizing cryo-damages and preserving their biological function. The freeze-thaw processes of cryopreservation may induce, in fact, morphological and structural damages of oocytes and tissue mainly due to the formation of intracellular ice and to the toxicity of cryoprotectant. The most used cryo-protocol is the slow freezing procedure, but recently many authors have proposed vitrification as an alternative, because of its simplicity. The damage extent and the quality of follicles after cryopreservation are usually evaluated morphologically by conventional histological procedures, light and electron microscopy. Our laboratory, to further improve the evaluation and to better investigate damages, is adopting a combination of Synchrotron soft X-ray Microscopy (at TwinMic – Elettra) and XRF at different incident energies (at TwinMic – Elettra and ID21 – ESRF). X-ray techniques were performed on histological sections at micro and sub-micron resolution. Phase contrast and absorption images revealed changes in the compactness of the tissues, as well as cellular abnormalities revealed at sub-micrometric resolution. The distributions of the elements detected at 7.3 and 1.5 keV were compared and particularly Cl resulted to be indicative of follicle integrity. The results demonstrate the utility and the potential of X-ray microscopy and fluorescence in this research field.

Effects of Re-heating Tissue Samples to Core Body Temperature on High-Velocity Ballistic Projectile-tissue Interactions.

PubMed

Humphrey, Caitlin; Henneberg, Maciej; Wachsberger, Christian; Maiden, Nicholas; Kumaratilake, Jaliya

2017-11-01

Damage produced by high-speed projectiles on organic tissue will depend on the physical properties of the tissues. Conditioning organic tissue samples to human core body temperature (37°C) prior to conducting ballistic experiments enables their behavior to closely mimic that of living tissues. To minimize autolytic changes after death, the tissues are refrigerated soon after their removal from the body and re-heated to 37°C prior to testing. This research investigates whether heating 50-mm-cube samples of porcine liver, kidney, and heart to 37°C for varying durations (maximum 7 h) can affect the penetration response of a high-speed, steel sphere projectile. Longer conditioning times for heart and liver resulted in a slight loss of velocity/energy of the projectile, but the reverse effect occurred for the kidney. Possible reasons for these trends include autolytic changes causing softening (heart and liver) and dehydration causing an increase in density (kidney). © 2017 American Academy of Forensic Sciences.

A PEG-Based Hydrogel for Effective Wound Care Management

PubMed Central

Chen, Sen-Lu; Fu, Ru-Huei; Liao, Shih-Fei; Liu, Shih-Ping; Lin, Shinn-Zong; Wang, Yu-Chi

2018-01-01

It is extremely challenging to achieve strong adhesion in soft tissues while minimizing toxicity, tissue damage, and other side effects caused by wound sealing materials. In this study, flexible synthetic hydrogel sealants were prepared based on polyethylene glycol (PEG) materials. PEG is a synthetic material that is nontoxic and inert and, thus, suitable for use in medical products. We evaluated the in vitro biocompatibility tests of the dressings to assess cytotoxicity and irritation, sensitization, pyrogen toxicity, and systemic toxicity following the International Organization for Standardization 10993 standards and the in vivo effects of the hydrogel samples using Coloskin liquid bandages as control samples for potential in wound closure. PMID:29637814

Intravital multiphoton imaging of mouse tibialis anterior muscle

PubMed Central

Lau, Jasmine; Goh, Chi Ching; Devi, Sapna; Keeble, Jo; See, Peter; Ginhoux, Florent; Ng, Lai Guan

2016-01-01

ABSTRACT Intravital imaging by multiphoton microscopy is a powerful tool to gain invaluable insight into tissue biology and function. Here, we provide a step-by-step tissue preparation protocol for imaging the mouse tibialis anterior skeletal muscle. Additionally, we include steps for jugular vein catheterization that allow for well-controlled intravenous reagent delivery. Preparation of the tibialis anterior muscle is minimally invasive, reducing the chances of inducing damage and inflammation prior to imaging. The tibialis anterior muscle is useful for imaging leukocyte interaction with vascular endothelium, and to understand muscle contraction biology. Importantly, this model can be easily adapted to study neuromuscular diseases and myopathies. PMID:28243520

Simulation of temperature distribution in tumor Photothermal treatment

NASA Astrophysics Data System (ADS)

Zhang, Xiyang; Qiu, Shaoping; Wu, Shulian; Li, Zhifang; Li, Hui

2018-02-01

The light transmission in biological tissue and the optical properties of biological tissue are important research contents of biomedical photonics. It is of great theoretical and practical significance in medical diagnosis and light therapy of disease. In this paper, the temperature feedback-controller was presented for monitoring photothermal treatment in realtime. Two-dimensional Monte Carlo (MC) and diffuse approximation were compared and analyzed. The results demonstrated that diffuse approximation using extrapolated boundary conditions by finite element method is a good approximation to MC simulation. Then in order to minimize thermal damage, real-time temperature monitoring was appraised by proportional-integral-differential (PID) controller in the process of photothermal treatment.

Rare Earth Doped IR Fiber Lasers For Medical Applications

NASA Astrophysics Data System (ADS)

Esterowitz, Leon; Allen, Roger

1989-06-01

Trivalent rare earth doped lasers in fluorozirconate glasses and fibers that lase between 2 and 3 μm are reviewed. There have been a large number of laser-fiber optic systems below 2pm developed for clinical microsurgery at a variety of sites. The required flexibility of the fiber optic waveguide varies with the clinical use, such as: intraocular (through a small diameter rigid tube), endoscopically accessible pulmonary and gastric mucosa (through a port of a fiber-optic endoscope of intermediate flexibility), and intra-arterial (as an integral part of a flexible catheter, which in the case of the coronaries must be very flexible so as to negotiate abrupt bends and bifurcations without damage to the vessels). Laser energy absorbed by tissue is capable of coagulation of tissue (denaturation of structural proteins), melting of fatty deposits or other structures (solid or gel to liquid phase transitions), as well as direct breakage of chemical bonds by high energy photons. It is of general interest to develop a pulsed laser system transmitted through flexible fiber optics that is capable of precise ablation of targeted tissue with minimal damage to the remaining tissue. Ideally, the device should be able to ablate any tissue because of the general absorptive properties of tissue, and not a specific chromophore such as melanin or hemoglobin, the concentration of which varies widely among tissues. Two obvious ubiquitous chromophores have been widely discussed: 1) proteins and nucleic acids whose high concentration and absorption coefficients lead to strong tissue absorption in the ultraviolet and 2) water whose strong infrared absorption bands have been widely utilized in CO2 laser surgery. Non-linear absorption occurring at very high power densities (~1 GW/cm2) has been shown to be very effective for non-invasive ocular (an optically transparent field) microsurgery at the image plane of a slit lamp, but this approach appears impractical in fiber optic systems because of similar non-linear damage mechanisms within the fiber.

Anti-lysophosphatidic acid antibodies improve traumatic brain injury outcomes

PubMed Central

2014-01-01

Background Lysophosphatidic acid (LPA) is a bioactive phospholipid with a potentially causative role in neurotrauma. Blocking LPA signaling with the LPA-directed monoclonal antibody B3/Lpathomab is neuroprotective in the mouse spinal cord following injury. Findings Here we investigated the use of this agent in treatment of secondary brain damage consequent to traumatic brain injury (TBI). LPA was elevated in cerebrospinal fluid (CSF) of patients with TBI compared to controls. LPA levels were also elevated in a mouse controlled cortical impact (CCI) model of TBI and B3 significantly reduced lesion volume by both histological and MRI assessments. Diminished tissue damage coincided with lower brain IL-6 levels and improvement in functional outcomes. Conclusions This study presents a novel therapeutic approach for the treatment of TBI by blocking extracellular LPA signaling to minimize secondary brain damage and neurological dysfunction. PMID:24576351

[Vital pulp therapy of damaged dental pulp].

PubMed

Xuedong, Zhou; Dingming, Huang; Jianguo, Liu; Zhengwei, Huang; Xin, Wei; Deqin, Yang; Jin, Zhao; Liming, Chen; Lin, Zhu; Yanhong, Li; Jiyao, Li

2017-08-01

The development of an expert consensus on vital pulp therapy can provide practical guidance for the improvement of pulp damage care in China. Dental pulp disease is a major type of illness that adversely affects human oral health. Pulp capping and pulpotomy are currently the main methods for vital pulp therapy. Along with the development of minimal invasion cosmetic dentistry, using different treatment technologies and materials reasonably, preserving healthy tooth tissue, and extending tooth save time have become urgent problems that call for immediate solution in dental clinics. This paper summarizes the experiences and knowledge of endodontic experts. We develop a clinical path of vital pulp therapy for clinical work by utilizing the nature, approach, and degree of pulp damage as references, defense and self-repairing ability of pulp as guidance, and modern technologies of diagnosis and treatment as means.

Use of minimally invasive spine surgical instruments for the treatment of bone tumors.

PubMed

Reeves, Russell A; DeWolf, Matthew C; Shaughnessy, Peter J; Ames, James B; Henderson, Eric R

2017-11-01

Orthopedic oncologists often encounter patients with minor bony lesions that are difficult to access surgically and therefore require large exposures out of proportion to the severity of disease that confer significant patient morbidity. Minimally invasive surgical techniques offer the advantage of smaller incisions, shorter operative times, decreased tissue damage, and decreased costs. A variety of surgical procedures have emerged using minimally invasive technologies, particularly in the field of spine surgery. Areas covered: In this article, we describe the Minimal Exposure Tubular Retractor (METRx TM ) System which is a minimally invasive surgical device that utilizes a series of dilators to permit access to a surgical site of interest. This system was developed for use in treatment of disc herniation, spinal stenosis, posterior lumbar interbody fusion, transforaminal lumbar interbody fusion and spinal cord stimulation implantation. We also describe novel uses of this system for minimally invasive biopsy and treatment of benign and metastatic bone lesions at our institution. Expert commentary: Minimally invasive surgical techniques will continue to expand into the field of orthopedic oncology. With a greater number of studies proving the safety and effectiveness of this technique, the demand for minimally invasive treatments will grow.

Optical coherence tomography image-guided smart laser knife for surgery.

PubMed

Katta, Nitesh; McElroy, Austin B; Estrada, Arnold D; Milner, Thomas E

2018-03-01

Surgical oncology can benefit from specialized tools that enhance imaging and enable precise cutting and removal of tissue without damage to adjacent structures. The combination of high-resolution, fast optical coherence tomography (OCT) co-aligned with a nanosecond pulsed thulium (Tm) laser offers advantages over conventional surgical laser systems. Tm lasers provide superior beam quality, high volumetric tissue removal rates with minimal residual thermal footprint in tissue, enabling a reduction in unwanted damage to delicate adjacent sub-surface structures such as nerves or micro-vessels. We investigated such a combined Tm/OCT system with co-aligned imaging and cutting beams-a configuration we call a "smart laser knife." A blow-off model that considers absorption coefficients and beam delivery systems was utilized to predict Tm cut depth, tissue removal rate and spatial distribution of residual thermal injury. Experiments were performed to verify the volumetric removal rate predicted by the model as a function of average power. A bench-top, combined Tm/OCT system was constructed using a 15W 1940 nm nanosecond pulsed Tm fiber laser (500 μJ pulse energy, 100 ns pulse duration, 30 kHz repetition rate) for removing tissue and a swept source laser (1310 ± 70 nm, 100 kHz sweep rate) for OCT imaging. Tissue phantoms were used to demonstrate precise surgery with blood vessel avoidance. Depth imaging informed cutting/removal of targeted tissue structures by the Tm laser was performed. Laser cutting was accomplished around and above phantom blood vessels while avoiding damage to vessel walls. A tissue removal rate of 5.5 mm 3 /sec was achieved experimentally, in comparison to the model prediction of approximately 6 mm 3 /sec. We describe a system that combines OCT and laser tissue modification with a Tm laser. Simulation results of the tissue removal rate using a simple model, as a function of average power, are in good agreement with experimental results using tissue phantoms. Lasers Surg. Med. 50:202-212, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

As we age: Does slippage of quality control in the immune system lead to collateral damage?

PubMed

Müller, Ludmila; Pawelec, Graham

2015-09-01

The vertebrate adaptive immune system is remarkable for its possession of a very broad range of antigen receptors imbuing the system with exquisite specificity, in addition to the phagocytic and inflammatory cells of the innate system shared with invertebrates. This system requires strict control both at the level of the generation the cells carrying these receptors and at the level of their activation and effector function mediation in order to avoid autoimmunity and mitigate immune pathology. Thus, quality control checkpoints are built into the system at multiple nodes in the response, relying on clonal selection and regulatory networks to maximize pathogen-directed effects and minimize collateral tissue damage. However, these checkpoints are compromised with age, resulting in poorer immune control manifesting as tissue-damaging autoimmune and inflammatory phenomena which can cause widespread systemic disease, paradoxically compounding the problems associated with increased susceptibility to infectious disease and possibly cancer in the elderly. Better understanding the reasons for slippage of immune control will pave the way for developing rational strategies for interventions to maintain appropriate immunity while reducing immunopathology. Copyright © 2015 Elsevier B.V. All rights reserved.

Precision resection of intestine using ultrashort laser pulses

NASA Astrophysics Data System (ADS)

Beck, Rainer J.; Gora, Wojciech S.; Jayne, David; Hand, Duncan P.; Shephard, Jonathan D.

2016-03-01

Endoscopic resection of early colorectal neoplasms typically employs electrocautery tools, which lack precision and run the risk of full thickness thermal injury to the bowel wall with subsequent perforation. We present a means of endoluminal colonic ablation using picosecond laser pulses as a potential alternative to mitigate these limitations. High intensity ultrashort laser pulses enable nonlinear absorption processes, plasma generation, and as a consequence a predominantly non-thermal ablation regimen. Robust process parameters for the laser resection are demonstrated using fresh ex vivo pig intestine samples. Square cavities with comparable thickness to early colorectal neoplasms are removed for a wavelength of 1030 nm and 515 nm using a picosecond laser system. The corresponding histology sections exhibit in both cases only minimal collateral damage to the surrounding tissue. The ablation depth can be controlled precisely by means of the pulse energy. Overall, the application of ultrafast lasers for the resection of intestine enables significantly improved precision and reduced thermal damage to the surrounding tissue compared to conventional electrocautery.

Introduction of argon beam coagulation functionality to robotic procedures using the ABC D-Flex probe: equivalency to an existing laparoscopic instrument

NASA Astrophysics Data System (ADS)

Merchel, Renée. A.; Barnes, Kelli S.; Taylor, Kenneth D.

2015-03-01

INTRODUCTION: The ABC® D-Flex Probe utilizes argon beam coagulation (ABC) technology to achieve hemostasis during minimally invasive surgery. A handle on the probe allows for integration with robotic surgical systems and introduces ABC to the robotic toolbox. To better understand the utility of D-Flex, this study compares the performance of the D-Flex probe to an existing ABC laparoscopic probe through ex vivo tissue analysis. METHODS: Comparisons were performed to determine the effect of four parameters: ABC device, tissue type, activation duration, and distance from tissue. Ten ABC D-Flex probes were used to create 30 burn samples for each comparison. Ex vivo bovine liver and porcine muscle were used as tissue models. The area and depth of each burn was measured using a light microscope. The resulting dimensional data was used to correlate tissue effect with each variable. RESULTS: D-Flex created burns which were smaller in surface area than the laparoscopic probe at all power levels. Additionally, D-Flex achieved thermal penetration levels equivalent to the laparoscopic probe. CONCLUSION: D-Flex implements a small 7F geometry which creates a more focused beam. When used with robotic precision, quick localized superficial hemostasis can be achieved with minimal collateral damage. Additionally, D-Flex achieved equivalent thermal penetration levels at lower power and argon flow-rate settings than the laparoscopic probe.

Near infrared laser-tissue welding using nanoshells as an exogenous absorber.

PubMed

Gobin, Andre M; O'Neal, D Patrick; Watkins, Daniel M; Halas, Naomi J; Drezek, Rebekah A; West, Jennifer L

2005-08-01

Gold nanoshells are a new class of nanoparticles that can be designed to strongly absorb light in the near infrared (NIR). These particles provide much larger absorption cross-sections and efficiency than can be achieved with currently used chemical chromophores without photobleaching. In these studies, we have investigated the use of gold nanoshells as exogenous NIR absorbers to facilitate NIR laser-tissue welding. Gold nanoshells with peak extinction matching the NIR wavelength of the laser being used were manufactured and suspended in an albumin solder. Optimization work was performed on ex vivo muscle samples and then translated into testing in an in vivo rat skin wound-healing model. Mechanical testing of the muscle samples was immediately performed and compared to intact tissue mechanical properties. In the in vivo study, full thickness incisions in the dorsal skin of rats were welded, and samples of skin were excised at 0, 5, 10, 21, and 32 days for analysis of strength and wound healing response. Mechanical testing of nanoshell-solder welds in muscle revealed successful fusion of tissues with tensile strengths of the weld site equal to the uncut tissue. No welding was accomplished with this light source when using solder formulations without nanoshells. Mechanical testing of the skin wounds showed sufficient strength for closure and strength increased over time. Histological examination showed good wound-healing response in the soldered skin. The use of nanoshells as an exogenous absorber allows the usage of light sources that are minimally absorbed by tissue components, thereby, minimizing damage to surrounding tissue and allowing welding of thicker tissues. (c) 2005 Wiley-Liss, Inc.

Trumpet Laminectomy Microdecompression for Lumbal Canal Stenosis

PubMed Central

Yasuda, Muneyoshi; Arifin, Muhammad Zafrullah; Takayasu, Masakazu; Faried, Ahmad

2014-01-01

Microsurgery techniques are useful innovations towards minimizing the insult of canal stenosis. Here, we describe the trumpet laminectomy microdecompression (TLM) technique, advantages and disadvantages. Sixty-two TLM patients with lumbar disc herniation, facet hypertrophy or yellow ligament or intracanal granulation tissue. The symptoms are low back pain, dysesthesia and severe pain on both legs. Spine levels operated Th11-S1; the patients who had trumpet-type fenestration, 62.9% had hypertrophy of the facet joint, 11.3% had intracanal granulation tissue, 79.1% had hypertrophy of the yellow ligament and 64.5% had disc herniation. The average of procedure duration was 68.9 min and intraoperative blood loss was 47.4 mL. Intraoperative complications were found in 3.2% of patients, with dural damage but without cerebrospinal fluid leakage. The TLM can be performed for all ages and all levels of spinal canal stenosis, without the complication of spondilolistesis. The TLM has a shorter duration, with minimal intraoperative blood loss. PMID:25346821

MicroRNAs and toxicology: A love marriage.

PubMed

Schraml, Elisabeth; Hackl, Matthias; Grillari, Johannes

2017-01-01

With the dawn of personalized medicine, secreted microRNAs (miRNAs) have come into the very focus of biomarker development for various diseases. MiRNAs fulfil key requirements of diagnostic tools such as i) non or minimally invasive accessibility, ii) robust, standardized and non-expensive quantitative analysis, iii) rapid turnaround of the test result and iv) most importantly because they provide a comprehensive snapshot of the ongoing physiologic processes in cells and tissues that package and release miRNAs into cell-free space. These characteristics have also established circulating miRNAs as promising biomarker candidates for toxicological studies, where they are used as biomarkers of drug-, or chemical-induced tissue injury for safety assessment. The tissue-specificity and early release of circulating miRNAs upon tissue injury, when damage is still reversible, are main factors for their clinical utility in toxicology. Here we summarize in brief, current knowledge of this field.

Femtosecond lasers in ophthalmology: clinical applications in anterior segment surgery

NASA Astrophysics Data System (ADS)

Juhasz, Tibor; Nagy, Zoltan; Sarayba, Melvin; Kurtz, Ronald M.

2010-02-01

The human eye is a favored target for laser surgery due to its accessibility via the optically transparent ocular tissue. Femtosecond lasers with confined tissue effects and minimized collateral tissue damage are primary candidates for high precision intraocular surgery. The advent of compact diode-pumped femtosecond lasers, coupled with computer controlled beam delivery devices, enabled the development of high precision femtosecond laser for ophthalmic surgery. In this article, anterior segment femtosecond laser applications currently in clinical practice and investigation are reviewed. Corneal procedures evolved first and remain dominant due to easy targeting referenced from a contact surface, such as applanation lenses placed on the eye. Adding a high precision imaging technique, such as optical coherence tomography (OCT), can enable accurate targeting of tissue beyond the cornea, such as the crystalline lens. Initial clinical results of femtosecond laser cataract surgery are discussed in detail in the latter portion part of the article.

Biomaterial applications in cardiovascular tissue repair and regeneration

PubMed Central

Lam, Mai T; Wu, Joseph C

2013-01-01

Cardiovascular disease physically damages the heart, resulting in loss of cardiac function. Medications can help alleviate symptoms, but it is more beneficial to treat the root cause by repairing injured tissues, which gives patients better outcomes. Besides heart transplants, cardiac surgeons use a variety of methods for repairing different areas of the heart such as the ventricular septal wall and valves. A multitude of biomaterials are used in the repair and replacement of impaired heart tissues. These biomaterials fall into two main categories: synthetic and natural. Synthetic materials used in cardiovascular applications include polymers and metals. Natural materials are derived from biological sources such as human donor or harvested animal tissues. A new class of composite materials has emerged to take advantage of the benefits of the strengths and minimize the weaknesses of both synthetic and natural materials. This article reviews the current and prospective applications of biomaterials in cardiovascular therapies. PMID:23030293

Quantifying thermal modifications on laser welded skin tissue

NASA Astrophysics Data System (ADS)

Tabakoglu, Hasim Ö.; Gülsoy, Murat

2011-02-01

Laser tissue welding is a potential medical treatment method especially on closing cuts implemented during any kind of surgery. Photothermal effects of laser on tissue should be quantified in order to determine optimal dosimetry parameters. Polarized light and phase contrast techniques reveal information about extend of thermal change over tissue occurred during laser welding application. Change in collagen structure in skin tissue stained with hematoxilen and eosin samples can be detected. In this study, three different near infrared laser wavelengths (809 nm, 980 nm and 1070 nm) were compared for skin welding efficiency. 1 cm long cuts were treated spot by spot laser application on Wistar rats' dorsal skin, in vivo. In all laser applications, 0.5 W of optical power was delivered to the tissue, 5 s continuously, resulting in 79.61 J/cm2 energy density (15.92 W/cm2 power density) for each spot. The 1st, 4th, 7th, 14th, and 21st days of recovery period were determined as control days, and skin samples needed for histology were removed on these particular days. The stained samples were examined under a light microscope. Images were taken with a CCD camera and examined with imaging software. 809 Nm laser was found to be capable of creating strong full-thickness closure, but thermal damage was evident. The thermal damage from 980 nm laser welding was found to be more tolerable. The results showed that 1070 nm laser welding produced noticeably stronger bonds with minimal scar formation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wendler, Johann Jakob, E-mail: johann.wendler@med.ovgu.de; Ricke, Jens, E-mail: jens.Ricke@med.ovgu.de; Pech, Maciej, E-mail: macej.pech@med.ovgu.de

IntroductionIt is postulated that focal IRE affords complete ablation of soft-tissue tumours while protecting the healthy peritumoral tissue. Therefore, IRE may be an interesting option for minimally invasive, kidney-tissue-sparing, non-thermal ablation of renal tumours.AimWith this current pilot study (“IRENE trial”), we present the first detailed histopathological data of IRE of human RCC followed by delayed tumour resection. The aim of this interim analysis of the first three patients was to investigate the ablation efficiency of percutaneous image-guided focal IRE in RCC, to assess whether a complete ablation of T1a RCC and tissue preservation with the NanoKnife system is possible andmore » to decide whether the ablation parameters need to be altered.MethodsFollowing resection 4 weeks after percutaneous IRE, the success of ablation and detailed histopathological description were used to check the ablation parameters.ResultsThe IRE led to a high degree of damage to the renal tumours (1 central, 2 peripheral; size range 15–17 mm). The postulated homogeneous, isomorphic damage was only partly confirmed. We found a zonal structuring of the ablation zone, negative margins and, enclosed within the ablation zone, very small tumour residues of unclear malignancy.ConclusionAccording to these initial, preliminary study results of the first three renal cases, a new zonal distribution of IRE damage was described and the curative intended, renal saving focal ablation of localised RCC below <3 cm by percutaneous IRE by the NanoKnife system appears to be possible, but needs further, systematic evaluation for this treatment method and treatment protocol.« less

Temperature Modulation of Electric Fields in Biological Matter

PubMed Central

Daniels, Charlotte S.; Rubinsky, Boris

2011-01-01

Pulsed electric fields (PEF) have become an important minimally invasive surgical technology for various applications including genetic engineering, electrochemotherapy and tissue ablation. This study explores the hypothesis that temperature dependent electrical parameters of tissue can be used to modulate the outcome of PEF protocols, providing a new means for controlling and optimizing this minimally invasive surgical procedure. This study investigates two different applications of cooling temperatures applied during PEF. The first case utilizes an electrode which simultaneously delivers pulsed electric fields and cooling temperatures. The subsequent results demonstrate that changes in electrical properties due to temperature produced by this configuration can substantially magnify and confine the electric fields in the cooled regions while almost eliminating electric fields in surrounding regions. This method can be used to increase precision in the PEF procedure, and eliminate muscle contractions and damage to adjacent tissues. The second configuration considered introduces a third probe that is not electrically active and only applies cooling boundary conditions. This second study demonstrates that in this probe configuration the temperature induced changes in electrical properties of tissue substantially reduce the electric fields in the cooled regions. This novel treatment can potentially be used to protect sensitive tissues from the effect of the PEF. Perhaps the most important conclusion of this investigation is that temperature is a powerful and accessible mechanism to modulate and control electric fields in biological tissues and can therefore be used to optimize and control PEF treatments. PMID:21695144

Inflammation: friend or foe for animal production?

PubMed

Broom, Leon J; Kogut, Michael H

2018-02-01

Inflammation is an essential immune response that seeks to contain microbial infection and repair damaged tissue. Increased pro-inflammatory mediators have been associated with enhanced resistance to a range of important poultry and pig pathogens. However, inflammation may also have undesirable consequences, including potentially exacerbating tissue damage and diverting nutrients away from productive purposes. The negative effects of inflammation have led to the active pursuit of anti-inflammatory feed additives and/or strategies. These approaches may, however, impair the ability of an animal to respond appropriately and effectively to the array of pathogens that are likely to be encountered in commercial production, and specifically young animals who may be particularly reliant on innate immune responses. Thus, promoting an animal's capacity to mount a rapid, acute inflammatory response to control and contain the infection and the timely transition to anti-inflammatory, tissue repair processes, and a homeostatic state are suggested as the optimum scenario to maintain an animal's resistance to pathogens and minimize non-productive nutrient losses. Important future studies will help to unravel the trade-offs, and relevant metabolic pathways, between robust immune defense and optimum productive performance, and thus provide real insight into methods to appropriately influence this relationship. © 2017 Poultry Science Association Inc.

Whole-body vibration of mice induces articular cartilage degeneration with minimal changes in subchondral bone.

PubMed

McCann, M R; Yeung, C; Pest, M A; Ratneswaran, A; Pollmann, S I; Holdsworth, D W; Beier, F; Dixon, S J; Séguin, C A

2017-05-01

Low-amplitude, high-frequency whole-body vibration (WBV) has been adopted for the treatment of musculoskeletal diseases including osteoarthritis (OA); however, there is limited knowledge of the direct effects of vibration on joint tissues. Our recent studies revealed striking damage to the knee joint following exposure of mice to WBV. The current study examined the effects of WBV on specific compartments of the murine tibiofemoral joint over 8 weeks, including microarchitecture of the tibia, to understand the mechanisms associated with WBV-induced joint damage. Ten-week-old male CD-1 mice were exposed to WBV (45 Hz, 0.3 g peak acceleration; 30 min/day, 5 days/week) for 4 weeks, 8 weeks, or 4 weeks WBV followed by 4 weeks recovery. The knee joint was evaluated histologically for tissue damage. Architecture of the subchondral bone plate, subchondral trabecular bone, primary and secondary spongiosa of the tibia was assessed using micro-CT. Meniscal tears and focal articular cartilage damage were induced by WBV; the extent of damage increased between 4 and 8-week exposures to WBV. WBV did not alter the subchondral bone plate, or trabecular bone of the tibial spongiosa; however, a transient increase was detected in the subchondral trabecular bone volume and density. The lack of WBV-induced changes in the underlying subchondral bone suggests that damage to the articular cartilage may be secondary to the meniscal injury we detected. Our findings underscore the need for further studies to assess the safety of WBV in the human population to avoid long-term joint damage. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Retinotomy using an erbium:YAG laser on human autopsy eyes

NASA Astrophysics Data System (ADS)

Ellsworth, Lansing G.; Kramer, Theresa R.; Noecker, Robert J.; Snyder, Robert W.; Yarborough, J. Michael

1994-06-01

Mid-IR lasers that operate near the absorption peak of water have a short penetration depth in ocular tissues. Ablation of tissue can be accomplished with minimal coagulative damage to underlying structures. We used an erbium:YAG laser equipped with a contact probe to create retinotomy sites in the human retina of eye bank eyes. An erbium:YAG laser (2.94 micrometers ) equipped with an infrared transmitting glass fiber and a sapphire tip (400 micrometers ) was used to directly ablate the surface of the retina. We administered both single and multiple pulses to the macula and peripheral retina using energy levels from 4 to 16 mJ per pulse. The retinas were then examined histopathologically to evaluate the extent of ablation and coagulative damage. Single pulses at low energy levels were noted to cause ablative damage to the nerve fiber layer and ganglion cell layer without a notable coagulative effect. The mean ablation depth at lower energy levels was less than the mean ablation depth at higher energy levels. Extensive laser application produced disruption of the retinal pigment epithelium, choroid and sclera. the erbium:YAG laser equipped with a contact probe is an effective means of creating retinotomies in human autopsy eyes. When used in the single pulse mode at lower energy levels, the erbium:YAG laser appears capable of removing superficial retinal layers without damaging deeper structures.

Ultrafast Photoresponsive Starburst and Dendritic Fullerenyl Nanostructures for Broadband Nonlinear Photonic Material Applications

DTIC Science & Technology

2014-08-20

antenna located at the opposite cage pole area) by helical st-PMMA led to observation of broadband characteristics at 780 and 980 nm with 2PA cross...absorption (2PA) based photodynamic therapy4‒8 (2γ-PDT) against pathogens and cancer to minimize the damage to surrounding normal tissue. Photoresponsive...periconjugation with a physical separation distance of only ɛ.5 Ǻ between donor and acceptor moieties. This led to the realization of ultrafast intramolecular

Development of Improved Satellite-Linked Transmitters, Physiological Recorders, and Attachment Techniques for Monitoring Beaked Whales

DTIC Science & Technology

2010-09-01

our previous petals by 20% in order to minimize tissue damage upon entry while still maintaining enough retention power. We switched to using 0.020...whales in Southern California, and 5 LIMPET Mk10-A tags to sperm whales in Southeast Alaska. As of 30 September 2010, 1 of the Cuvier’s tags is still...sending dive depth data (94 days after attachment) and 3 of the sperm whale tags are still transmitting dive data (46 days after attachment

Assessment of FUS-Tissue Interactions In Vivo

NASA Astrophysics Data System (ADS)

Haritonova, Alyona V.

Focused ultrasound (FUS) has been proposed for a variety of minimally invasive therapeutic applications, including tumor ablation, neuromodulation, targeted drug delivery and blood brain barrier opening. To date, FUS beams have been primarily monitored through MR and ultrasound diagnostic imaging modalities. The recent introduction of real-time dual-mode ultrasound array (DMUA) systems offers a new paradigm for the guidance of therapeutic focused ultrasound. The DMUA approach allows for inherent registration between the therapeutic and imaging coordinate systems. In this thesis we investigated the use of ultrasound-based thermography to assess FUS-tissue interactions. Specifically, we focused on two aspects of image-guided therapy: 1) monitoring and localization of FUS-tissue interactions, and 2) tissue damage assessment. Towards this end, we presented first experimental results of ultrasound-guided transcranial FUS in a rat brain, both ex vivo and in vivo. DMUA imaging was used to monitor and localize FUS-tissue thermal interactions in real-time. The transcranial echo data allowed for a reliable estimation of temperature change in brain tissue, which had never been done before using ultrasound image guidance. Despite some measurable distortion and loss in focusing gain, transcranial FUS beams at 3.2 MHz were localized axially and laterally. This confirms the results obtained using DMUA-based transcranial ultrasound thermography. A high degree of focusing with the DMUA was then successfully leveraged to perform localized tissue damage assessment in both ex vivo and in vivo. The experimental results presented in this thesis demonstrate some of the unique aspects of image guidance using DMUAs, especially when FUS is subject to significant distortions as in transcranial applications.

Blood parameters and electroencephalographic responses of goats to slaughter without stunning.

PubMed

Sabow, A B; Goh, Y M; Zulkifli, I; Sazili, A Q; Kaka, U; Kadi, M Z A Ab; Ebrahimi, M; Nakyinsige, K; Adeyemi, K D

2016-11-01

The study compared changes in blood biochemistry, hormonal and electroencephalographic indices associated with possible noxious stimuli following neck cut slaughter in conscious, non-anaesthetized versus minimally-anaesthetized goats. Ten male Boer crossbreed goats were assigned into two groups and subjected to either slaughter conscious without stunning (SWS) or slaughter following minimal anaesthesia (SMA). Hormonal responses and changes in electroencephalographic (EEG) parameters were not influenced by slaughter method. The SWS goats had higher glucose and lactate than did SMA goats. It can be concluded that the noxious stimulus from the neck cut is present in both conscious and minimally anaesthetized goats. The application of slaughter without stunning causes changes in the EEG activities that are consistent with the presence of post slaughter noxious sensory input associated with tissue damage and would be expected to be experienced as pain in goats. Copyright © 2016. Published by Elsevier Ltd.

Two-photon calcium imaging in mice navigating a virtual reality environment.

PubMed

Leinweber, Marcus; Zmarz, Pawel; Buchmann, Peter; Argast, Paul; Hübener, Mark; Bonhoeffer, Tobias; Keller, Georg B

2014-02-20

In recent years, two-photon imaging has become an invaluable tool in neuroscience, as it allows for chronic measurement of the activity of genetically identified cells during behavior(1-6). Here we describe methods to perform two-photon imaging in mouse cortex while the animal navigates a virtual reality environment. We focus on the aspects of the experimental procedures that are key to imaging in a behaving animal in a brightly lit virtual environment. The key problems that arise in this experimental setup that we here address are: minimizing brain motion related artifacts, minimizing light leak from the virtual reality projection system, and minimizing laser induced tissue damage. We also provide sample software to control the virtual reality environment and to do pupil tracking. With these procedures and resources it should be possible to convert a conventional two-photon microscope for use in behaving mice.

Tissue Expanders and Proton Beam Radiotherapy: What You Need to Know

PubMed Central

Howarth, Ashley L.; Niska, Joshua R.; Brooks, Kenneth; Anand, Aman; Bues, Martin; Vargas, Carlos E.

2017-01-01

Summary: Proton beam radiotherapy (PBR) has gained acceptance for the treatment of breast cancer because of unique beam characteristics that allow superior dose distributions with optimal dose to the target and limited collateral damage to adjacent normal tissue, especially to the heart and lungs. To determine the compatibility of breast tissue expanders (TEs) with PBR, we evaluated the structural and dosimetric properties of 2 ex vivo models: 1 model with internal struts and another model without an internal structure. Although the struts appeared to have minimal impact, we found that the metal TE port alters PBR dynamics, which may increase proton beam range uncertainty. Therefore, submuscular TE placement may be preferable to subcutaneous TE placement to reduce the interaction of the TE and proton beam. This will reduce range uncertainty and allow for more ideal radiation dose distribution. PMID:28740794

New approach of Co2 laser use in plastic and dermo-cosmetic surgery

NASA Astrophysics Data System (ADS)

Trelles, Mario A.; Trelles, O. R.; Romero, L. F.

1996-01-01

Laboratory and mathematical skin examination has played an important role in defining the clinical usefulness and limitations of laser, developing concepts and techniques that have further improved the effectiveness of laser treatment. In addition to this, new technological developments over the years, have helped define the specificity of laser-tissue interaction. Instantaneous conversion by thermal energy of water in a liquid state to a gaseous state when irradiation of skin is done by high power density carbon dioxide laser in short pulses, occurs so quickly that there is minimal thermal conduction to the adjacent tissues structures. The zone of thermal injury could be minimized to the order of only 50 micron thick. In spite of the limited effects of heat conduction, coagulation in vessels can be obtained as well, since small blood vessels are immediately sealed by the laser. Modern carbon dioxide systems can be programmed and make it possible to reproduce shots precisely to vaporize identically thin layers of soft tissue, since absorption by intracellular water limits the depth of penetration. Moreover, collimated handpieces make it possible to deliver a fixed beam diameter and a constant power density as the handpiece is steadily moved over lesions situated on uneven facial contours. The use of large spot sizes gives a more uniform vaporization thus damaging adjacent tissues to a lesser degree, but enlarging of the spot size requires higher energy levels per pulse so that the whole surface can reach a sufficiently high fluence for clean vaporization to take place. For this to be achieved, the fluence required is about 4 - 5 J/cm2 and so UltraPulseR carbon dioxide laser with a 3 mm spot size may be operated with optimal parameters for clean ablation. The resulting surface, covered by dry debris, can be removed by gently scrubbing to avoid thermal build-up, otherwise this remaining tissue can act as a refracting surface as the practical absence of water content means that the carbon dioxide laser light is not efficiently absorbed. This process is repeated layer-by-layer using the same laser parameters until all remaining abnormal tissue has been grossly removed. Utilized as a chain of rapid, short (approx. 1 ms) pulses, with high peak power, tissue can be effectively eliminated, taking advantage of the concept of the known thermal relaxation time of soft tissue. The current laser systems which are built according to the new concept of high technology based upon the knowledge of laser tissue interaction, known as UltraPulsedR Carbon Dioxide Laser, are capable of precise ablation and also of being used in cosmetically sensitive areas with minimal thermal damage. Although the precise clinical role for this laser has yet to be accurately defined, the potential benefits offered by its use appear to be substantial.

Improved normal tissue protection by proton and X-ray microchannels compared to homogeneous field irradiation.

PubMed

Girst, S; Marx, C; Bräuer-Krisch, E; Bravin, A; Bartzsch, S; Oelfke, U; Greubel, C; Reindl, J; Siebenwirth, C; Zlobinskaya, O; Multhoff, G; Dollinger, G; Schmid, T E; Wilkens, J J

2015-09-01

The risk of developing normal tissue injuries often limits the radiation dose that can be applied to the tumour in radiation therapy. Microbeam Radiation Therapy (MRT), a spatially fractionated photon radiotherapy is currently tested at the European Synchrotron Radiation Facility (ESRF) to improve normal tissue protection. MRT utilizes an array of microscopically thin and nearly parallel X-ray beams that are generated by a synchrotron. At the ion microprobe SNAKE in Munich focused proton microbeams ("proton microchannels") are studied to improve normal tissue protection. Here, we comparatively investigate microbeam/microchannel irradiations with sub-millimetre X-ray versus proton beams to minimize the risk of normal tissue damage in a human skin model, in vitro. Skin tissues were irradiated with a mean dose of 2 Gy over the irradiated area either with parallel synchrotron-generated X-ray beams at the ESRF or with 20 MeV protons at SNAKE using four different irradiation modes: homogeneous field, parallel lines and microchannel applications using two different channel sizes. Normal tissue viability as determined in an MTT test was significantly higher after proton or X-ray microchannel irradiation compared to a homogeneous field irradiation. In line with these findings genetic damage, as determined by the measurement of micronuclei in keratinocytes, was significantly reduced after proton or X-ray microchannel compared to a homogeneous field irradiation. Our data show that skin irradiation using either X-ray or proton microchannels maintain a higher cell viability and DNA integrity compared to a homogeneous irradiation, and thus might improve normal tissue protection after radiation therapy. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Minimally invasive scoliosis treatment with a Ho:YAG laser

NASA Astrophysics Data System (ADS)

Rumpf, Christian G.; Lang, Robert D.; Goetz, Marcus H.

2000-11-01

Today most surgical treatment of spinal deformations is concentrated on invasive mechanical techniques with long operation times and major effects on the patient's mobility. The proposed minimally invasive technique using laser light for tissue ablation offers a possibility of gentle scoliosis treatment. It is thought that an early removal of the epiphysial growth zone on the convex side over several vertebrae results in a straightening of the spine. In a first evaluation, four different laser systems including argon ion, Nd:YAG (Q-switched), Nd:YAG (cw), and Ho:YAG laser were compared with respect to thermal damage to adjacent tissue, ablation rates, efficiency and laser handling. For in-vivo investigation, fresh lamb spine was used. Comparison showed that the Ho:YAG laser is the most appropriate laser for the given goal, providing efficient photoablation with moderate thermal effects on the adjacent tissue. In a second step the proposed minimally invasive operation technique was performed in in-vivo experiments on young foxhounds using 3D- thoracoscopic operation techniques. During these operations temperature mapping was done using fiber-optic fluorescent probes. After 12 months of normal growth the animals were sacrificed and x-ray as well as MRI was performed on the spine. First results show a positive effect of scoliotic growth in two cases. Being able to produce a scoliosis by hemiepiphysiodesis on the vertebra, It is thought that this technique is successful for a straightening of the spine on patients with scoliosis.

Assessing laser-tissue damage with bioluminescent imaging

NASA Astrophysics Data System (ADS)

Wilmink, Gerald J.; Opalenik, Susan R.; Beckham, Josh T.; Davidson, Jeffrey M.; Jansen, Eric D.

2006-07-01

Effective medical laser procedures are achieved by selecting laser parameters that minimize undesirable tissue damage. Traditionally, human subjects, animal models, and monolayer cell cultures have been used to study wound healing, tissue damage, and cellular effects of laser radiation. Each of these models has significant limitations, and consequently, a novel skin model is needed. To this end, a highly reproducible human skin model that enables noninvasive and longitudinal studies of gene expression was sought. In this study, we present an organotypic raft model (engineered skin) used in combination with bioluminescent imaging (BLI) techniques. The efficacy of the raft model was validated and characterized by investigating the role of heat shock protein 70 (hsp70) as a sensitive marker of thermal damage. The raft model consists of human cells incorporated into an extracellular matrix. The raft cultures were transfected with an adenovirus containing a murine hsp70 promoter driving transcription of luciferase. The model enables quantitative analysis of spatiotemporal expression of proteins using BLI. Thermal stress was induced on the raft cultures by means of a constant temperature water bath or with a carbon dioxide (CO2) laser (λ=10.6 µm, 0.679 to 2.262 W/cm2, cw, unfocused Gaussian beam, ωL=4.5 mm, 1 min exposure). The bioluminescence was monitored noninvasively with an IVIS 100 Bioluminescent Imaging System. BLI indicated that peak hsp70 expression occurs 4 to 12 h after exposure to thermal stress. A minimum irradiance of 0.679 W/cm2 activated the hsp70 response, and a higher irradiance of 2.262 W/cm2 was associated with a severe reduction in hsp70 response due to tissue ablation. Reverse transcription polymerase chain reaction demonstrated that hsp70 mRNA levels increased with prolonged heating exposures. Enzyme-linked immunosorbent protein assays confirmed that luciferase was an accurate surrogate for hsp70 intracellular protein levels. Hematoxylin and eosin stains verified the presence of the thermally denatured tissue regions. Immunohistochemical analyses confirmed that maximal hsp70 expression occurred at a depth of 150 µm. Bioluminescent microscopy was employed to corroborate these findings. These results indicate that quantitative BLI in engineered tissue equivalents provides a powerful model that enables sequential gene expression studies. Such a model can be used as a high throughput screening platform for laser-tissue interaction studies.

The effects of different fractions of Coriandrum sativum on pentylenetetrazole-induced seizures and brain tissues oxidative damage in rats.

PubMed

Anaeigoudari, Akbar; Hosseini, Mahmoud; Karami, Reza; Vafaee, Farzaneh; Mohammadpour, Toktam; Ghorbani, Ahmad; Sadeghnia, Hamid Reza

2016-01-01

In the present work, the effects of different fractions of Coriandrum sativum (C. sativum), on pentylenetetrazole (PTZ)-induced seizures and brain tissues oxidative damage were investigated in rats. The rats were divided into the following groups: (1) vehicle, (2) PTZ (90 mg/kg), (3) water fraction (WF) of C. sativum (25 and 100 mg/kg), (4) n-butanol fraction (NBF) of C. sativum (25 and 100 mg/kg), and (5) ethyl acetate fraction (EAF) of C. sativum (25 and 100 mg/kg). The first generalized tonic-clonic seizures (GTCS) latency in groups treated with 100 mg /kg of WF or EAF was significantly higher than that of PTZ group (p<0.01). In contrast to WF, the EAF and NBF were not effective in increasing the first minimal clonic seizure (MCS) latency. Malondialdehyde (MDA) levels in both cortical and hippocampal tissues of PTZ group were significantly higher than those of control animals (p<0.001). Pretreatment with WF, NBF, or EAF resulted in a significant reduction in the MDA levels of hippocampi (p<0.01 - p<0.001). Following PTZ administration, a significant reduction in total thiol groups was observed in the brain tissues (p<0.05). Pretreatment with WF and NBF significantly elevated thiol concentrations in cortical and hippocampal tissues, respectively (p<0.05). The present study showed that different fractions of C. sativum possess antioxidant activity in the brain and WF and EAF of this plant have anticonvulsant effects.

Comparing an optical parametric oscillator (OPO) as a viable alternative for mid-infrared tissue ablation with a free electron laser (FEL).

PubMed

Mackanos, Mark A; Simanovskii, Dmitrii M; Contag, Christopher H; Kozub, John A; Jansen, E Duco

2012-11-01

Beneficial medical laser ablation removes material efficiently with minimal collateral damage. A Mark-III free electron laser (FEL), at a wavelength of 6.45 μm has demonstrated minimal damage and high ablation yield in ocular and neural tissues. While this wavelength has shown promise for surgical applications, further advances are limited by the high overhead for FEL use. Alternative mid-infrared sources are needed for further development. We compared the FEL with a 5-μs pulse duration with a Q-switched ZGP-OPO with a 100-ns pulse duration at mid-infrared wavelengths. There were no differences in the ablation threshold of water and mouse dermis with these two sources in spite of the difference in their pulse structures. There was a significant difference in crater depth between the ZGP:OPO and the FEL. At 6.1 μm, the OPO craters are eight times the depth of the FEL craters. The OPO craters at 6.45 and 6.73 μm were six and five times the depth of the FEL craters, respectively. Bright-field (pump-probe) images showed the classic ablation mechanism from formation of a plume through collapse and recoil. The crater formation, ejection, and collapse phases occurred on a faster time-scale with the OPO than with the FEL. This research showed that a ZGP-OPO laser could be a viable alternative to FEL for clinical applications.

[Dose rate-dependent cellular and molecular effects of ionizing radiation].

PubMed

Przybyszewski, Waldemar M; Wideł, Maria; Szurko, Agnieszka; Maniakowski, Zbigniew

2008-09-11

The aim of radiation therapy is to kill tumor cells while minimizing damage to normal cells. The ultimate effect of radiation can be apoptotic or necrotic cell death as well as cytogenetic damage resulting in genetic instability and/or cell death. The destructive effects of radiation arise from direct and indirect ionization events leading to peroxidation of macromolecules, especially those present in lipid-rich membrane structures as well as chromatin lipids. Lipid peroxidative end-products may damage DNA and proteins. A characteristic feature of radiation-induced peroxidation is an inverse dose-rate effect (IDRE), defined as an increase in the degree of oxidation(at constant absorbed dose) accompanying a lower dose rate. On the other hand, a low dose rate can lead to the accumulation of cells in G2, the radiosensitive phase of the cell cycle since cell cycle control points are not sensitive to low dose rates. Radiation dose rate may potentially be the main factor improving radiotherapy efficacy as well as affecting the intensity of normal tissue and whole-body side effects. A better understanding of dose rate-dependent biological effects may lead to improved therapeutic intervention and limit normal tissue reaction. The study reviews basic biological effects that depend on the dose rate of ionizing radiation.

Skin graft take and healing following 193-nm excimer, continuous-wave carbon dioxide (CO2), pulsed CO2, or pulsed holmium: YAG laser ablation of the graft bed.

PubMed

Green, H A; Burd, E E; Nishioka, N S; Compton, C C

1993-08-01

Ablative lasers have been used for cutaneous surgery for greater than two decades since they can remove skin and skin lesions bloodlessly and efficiently. Because full-thickness skin wounds created after thermal laser ablation may require skin grafting in order to heal, we have examined the effect of the residual laser-induced thermal damage in the wound bed on subsequent skin graft take and healing. In a pig model, four different pulsed and continuous-wave lasers with varying wavelengths and radiant energy exposures were used to create uniform fascial graft bed thermal damage of approximately 25, 160, 470, and 1100 microns. Meshed split-thickness skin graft take and healing on the thermally damaged fascial graft beds were examined on a gross and microscopic level on days 3 and 7, and then weekly up to 42 days. Laser-induced thermal damage on the graft bed measuring greater than 160 +/- 60 microns in depth significantly decreased skin graft take. Other deleterious effects included delayed graft revascularization, increased inflammatory cell infiltrate at the graft-wound bed interface, and accelerated formation of hypertrophied fibrous tissue within the graft bed and underlying muscle. Ablative lasers developed for cutaneous surgery should create less than 160 +/- 60 microns of residual thermal damage to permit optimal skin graft take and healing. Pulsed carbon dioxide and 193-nm excimer lasers may be valuable instruments for the removal of full-thickness skin, skin lesions, and necrotic tissue, since they create wound beds with minimal thermal damage permitting graft take comparable to that achieved with standard surgical techniques.

An arsenal of magnetic nanoparticles; perspectives in the treatment of cancer.

PubMed

Karponis, Dimitrios; Azzawi, May; Seifalian, Alexander

2016-08-01

Nanomedicine is an emerging field, which constitutes a new direction in the treatment of cancer. Magnetic nanoparticles (MNPs) can circumvent vascular tissue to concentrate at the site of the tumor. Under the influence of an external, alternating magnetic field, MNPs generate high temperatures within the tumor and ablate malignant cells while inflicting minimal damage to healthy host tissue. Due to their theranostic properties, they constitute a promising candidate for the treatment of cancer. A critical review of the type, size and therapeutic effect of different MNPs is presented, following an appraisal of the literature in the last 5 years. This is a multibillion dollar industry, with a few studies moving to clinical trials within the next 5 years.

Intraluminal radiation for esophageal cancer: a Howard University technique.

PubMed

Moorthy, C R; Nibhanupudy, J R; Ashayeri, E; Goldson, A L; Espinoza, M C; Nidiry, J J; Warner, O G; Roux, V J

1982-03-01

The objective of radiotherapeutic management in esophageal cancer is to accomplish maximum tumor sterilization with minimal normal tissue damage. This sincere effort is most often countered by the differential in tumor dose response vs normal tissue tolerance. Intraluminal isotope radiation, with its inherent advantage of rapid dose falloff, spares the lungs, the spinal cord, and other vital structures, yet yields adequately high doses to esophageal tumor. Though in existence since the turn of the century, the method of intracavitary radium bougie application dropped out of favor due to technical difficulties imposed by the size of the radium source and radiation exposure to the personnel involved. The authors describe a simple "iridium 192 afterloading intraluminal technique" that eliminates technical problems and reduces radiation exposure considerably.

Reduced Leukocyte Infiltration in Absence of Eosinophils Correlates with Decreased Tissue Damage and Disease Susceptibility in ΔdblGATA Mice during Murine Neurocysticercosis.

PubMed

Mishra, Pramod K; Li, Qun; Munoz, Luis E; Mares, Chris A; Morris, Elizabeth G; Teale, Judy M; Cardona, Astrid E

2016-06-01

Neurocysticercosis (NCC) is one of the most common helminth parasitic diseases of the central nervous system (CNS) and the leading cause of acquired epilepsy worldwide. NCC is caused by the presence of the metacestode larvae of the tapeworm Taenia solium within brain tissues. NCC patients exhibit a long asymptomatic phase followed by a phase of symptoms including increased intra-cranial pressure and seizures. While the asymptomatic phase is attributed to the immunosuppressive capabilities of viable T. solium parasites, release of antigens by dying organisms induce strong immune responses and associated symptoms. Previous studies in T. solium-infected pigs have shown that the inflammatory response consists of various leukocyte populations including eosinophils, macrophages, and T cells among others. Because the role of eosinophils within the brain has not been investigated during NCC, we examined parasite burden, disease susceptibility and the composition of the inflammatory reaction in the brains of infected wild type (WT) and eosinophil-deficient mice (ΔdblGATA) using a murine model of NCC in which mice were infected intracranially with Mesocestoides corti, a cestode parasite related to T. solium. In WT mice, we observed a time-dependent induction of eosinophil recruitment in infected mice, contrasting with an overall reduced leukocyte infiltration in ΔdblGATA brains. Although, ΔdblGATA mice exhibited an increased parasite burden, reduced tissue damage and less disease susceptibility was observed when compared to infected WT mice. Cellular infiltrates in infected ΔdblGATA mice were comprised of more mast cells, and αβ T cells, which correlated with an abundant CD8+ T cell response and reduced CD4+ Th1 and Th2 responses. Thus, our data suggest that enhanced inflammatory response in WT mice appears detrimental and associates with increased disease susceptibility, despite the reduced parasite burden in the CNS. Overall reduced leukocyte infiltration due to absence of eosinophils correlates with attenuated tissue damage and longer survival of ΔdblGATA mice. Therefore, our study suggests that approaches to clear NCC will require strategies to tightly control the host immune response while eradicating the parasite with minimal damage to brain tissue.

Reduced Leukocyte Infiltration in Absence of Eosinophils Correlates with Decreased Tissue Damage and Disease Susceptibility in ΔdblGATA Mice during Murine Neurocysticercosis

PubMed Central

Mishra, Pramod K.; Li, Qun; Munoz, Luis E.; Mares, Chris A.; Morris, Elizabeth G.; Teale, Judy M.; Cardona, Astrid E.

2016-01-01

Neurocysticercosis (NCC) is one of the most common helminth parasitic diseases of the central nervous system (CNS) and the leading cause of acquired epilepsy worldwide. NCC is caused by the presence of the metacestode larvae of the tapeworm Taenia solium within brain tissues. NCC patients exhibit a long asymptomatic phase followed by a phase of symptoms including increased intra-cranial pressure and seizures. While the asymptomatic phase is attributed to the immunosuppressive capabilities of viable T. solium parasites, release of antigens by dying organisms induce strong immune responses and associated symptoms. Previous studies in T. solium-infected pigs have shown that the inflammatory response consists of various leukocyte populations including eosinophils, macrophages, and T cells among others. Because the role of eosinophils within the brain has not been investigated during NCC, we examined parasite burden, disease susceptibility and the composition of the inflammatory reaction in the brains of infected wild type (WT) and eosinophil-deficient mice (ΔdblGATA) using a murine model of NCC in which mice were infected intracranially with Mesocestoides corti, a cestode parasite related to T. solium. In WT mice, we observed a time-dependent induction of eosinophil recruitment in infected mice, contrasting with an overall reduced leukocyte infiltration in ΔdblGATA brains. Although, ΔdblGATA mice exhibited an increased parasite burden, reduced tissue damage and less disease susceptibility was observed when compared to infected WT mice. Cellular infiltrates in infected ΔdblGATA mice were comprised of more mast cells, and αβ T cells, which correlated with an abundant CD8+ T cell response and reduced CD4+ Th1 and Th2 responses. Thus, our data suggest that enhanced inflammatory response in WT mice appears detrimental and associates with increased disease susceptibility, despite the reduced parasite burden in the CNS. Overall reduced leukocyte infiltration due to absence of eosinophils correlates with attenuated tissue damage and longer survival of ΔdblGATA mice. Therefore, our study suggests that approaches to clear NCC will require strategies to tightly control the host immune response while eradicating the parasite with minimal damage to brain tissue. PMID:27332553

EFFECTS OF CYCLIC FLEXURAL FATIGUE ON PORCINE BIOPROSTHETIC HEART VALVE HETEROGRAFT BIOMATERIALS

PubMed Central

Mirnajafi, Ali; Zubiate, Brett; Sacks, Michael S.

2009-01-01

While bioprosthetic heart valves (BHV) remain the primary treatment modality for adult heart valve replacement, continued problems with durability remain. Several studies have implicated flexure as a major damage mode in porcine-derived heterograft biomaterials used in BHV fabrication. While conventional accelerated wear testing can provide valuable insights into BHV damage phenomena, the constituent tissues are subjected to complex, time-varying deformation modes (i.e. tension and flexure), that do not allow for the control of the amount, direction, and location of flexure. Thus, in the present study customized fatigue testing devices were developed to subject circumferentially oriented porcine BHV tissue strips to controlled cyclic flexural loading. By using this approach, we were able to study layer-specific structural damage induced by cyclic flexural tensile and compressive stresses alone. 10×106, 25×106 and 50×106 cycle levels were used, with resulting changes in flexural stiffness and collagen structure assessed. Results indicated that flexural rigidity was markedly reduced after only 10×106 cycles, and progressively decayed at a lower rate with cycle number thereafter. Moreover, the against-curvature fatigue direction induced the most damage, suggesting that the ventricularis and fibrosa layers have low resistance to cyclic flexural compressive and tensile loads, respectively. The histological analyses indicated progressive collagen fiber delamination as early as 10×106 cycles, but otherwise no change in gross collagen orientation. Our results underscore that porcine-derived heterograft biomaterials are very sensitive to flexural fatigue, with delamination of the tissue layers the primary underlying mechanism. This appears to be in contrast to pericardial BHV, wherein high tensile stresses are considered to be the major cause of structural failure. These findings point towards the need for the development of chemical fixation technologies that minimize flexure induced damage to extend porcine heterograft biomaterial durability. PMID:20166221

Markers of oxidative damage to lipids, nucleic acids and proteins and antioxidant enzymes activities in Alzheimer's disease brain: A meta-analysis in human pathological specimens.

PubMed

Zabel, Matthew; Nackenoff, Alex; Kirsch, Wolff M; Harrison, Fiona E; Perry, George; Schrag, Matthew

2018-02-01

Oxidative stress and decreased cellular responsiveness to oxidative stress are thought to influence brain aging and Alzheimer's disease, but the specific patterns of oxidative damage and the underlying mechanism leading to this damage are not definitively known. The objective of this study was to define the pattern of changes in oxidative-stress related markers by brain region in human Alzheimer's disease and mild cognitive impairment brain tissue. Observational case-control studies were identified from systematic queries of PubMed, ISI Web of Science and Scopus databases and studies were evaluated with appropriate quality measures. The data was used to construct a region-by-region meta-analysis of malondialdehyde, 4-hydroxynonenal, protein carbonylation, 8-hydroxyguanine levels and superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase activities. We also evaluated ascorbic acid, tocopherol, uric acid and glutathione levels. The analysis was complicated in several cases by publication bias and/or outlier data. We found that malondialdehyde levels were slightly increased in the temporal and occipital lobes and hippocampus, but this analysis was significantly impacted by publication bias. 4-hydroxynonenal levels were unchanged in every brain region. There was no change in 8-hydroxyguanine level in any brain region and protein carbonylation levels were unchanged except for a slight increase in the occipital lobe. Superoxide dismutase, glutathione peroxidase and reductase and catalase activities were not decreased in any brain region. There was limited data reporting non-enzymatic antioxidant levels in Alzheimer's disease brain, although glutathione and tocopherol levels appear to be unchanged. Minimal quantitative data is available from brain tissue from patients with mild cognitive impairment. While there is modest evidence supporting minor regional changes in markers of oxidative damage, this analysis fails to identify a consistent pattern of pro-oxidative changes and accumulation of oxidative damage in bulk tissue analysis in the setting of Alzheimer's disease, as has been widely reported. Copyright © 2017 Elsevier Inc. All rights reserved.

Toxicity Minimized Cryoprotectant Addition and Removal Procedures for Adherent Endothelial Cells

PubMed Central

Davidson, Allyson Fry; Glasscock, Cameron; McClanahan, Danielle R.; Benson, James D.; Higgins, Adam Z.

2015-01-01

Ice-free cryopreservation, known as vitrification, is an appealing approach for banking of adherent cells and tissues because it prevents dissociation and morphological damage that may result from ice crystal formation. However, current vitrification methods are often limited by the cytotoxicity of the concentrated cryoprotective agent (CPA) solutions that are required to suppress ice formation. Recently, we described a mathematical strategy for identifying minimally toxic CPA equilibration procedures based on the minimization of a toxicity cost function. Here we provide direct experimental support for the feasibility of these methods when applied to adherent endothelial cells. We first developed a concentration- and temperature-dependent toxicity cost function by exposing the cells to a range of glycerol concentrations at 21°C and 37°C, and fitting the resulting viability data to a first order cell death model. This cost function was then numerically minimized in our state constrained optimization routine to determine addition and removal procedures for 17 molal (mol/kg water) glycerol solutions. Using these predicted optimal procedures, we obtained 81% recovery after exposure to vitrification solutions, as well as successful vitrification with the relatively slow cooling and warming rates of 50°C/min and 130°C/min. In comparison, conventional multistep CPA equilibration procedures resulted in much lower cell yields of about 10%. Our results demonstrate the potential for rational design of minimally toxic vitrification procedures and pave the way for extension of our optimization approach to other adherent cell types as well as more complex systems such as tissues and organs. PMID:26605546

Deformation and reperfusion damages and their accumulation in subcutaneous tissues during loading and unloading: a theoretical modeling of deep tissue injuries.

PubMed

Mak, Arthur F T; Yu, Yanyan; Kwan, Linda P C; Sun, Lei; Tam, Eric W C

2011-11-21

Deep tissue injuries (DTI) involve damages in the subcutaneous tissues under intact skin incurred by prolonged excessive epidermal loadings. This paper presents a new theoretical model for the development of DTI, broadly based on the experimental evidence in the literatures. The model covers the loading damages implicitly inclusive of both the direct mechanical and ischemic injuries, and the additional reperfusion damages and the competing healing processes during the unloading phase. Given the damage accumulated at the end of the loading period, the relative strength of the reperfusion and the healing capacity of the involved tissues system, the model provides a description of the subsequent damage evolution during unloading. The model is used to study parametrically the scenario when reperfusion damage dominates over healing upon unloading and the opposite scenario when the loading and subsequent reperfusion damages remain small relative to the healing capacity of the tissues system. The theoretical model provides an integrated understanding of how tissue damage may further build-up paradoxically even with unloading, how long it would take for the loading and reperfusion damages in the tissues to become fully recovered, and how such loading and reperfusion damages, if not given sufficient time for recovery, may accumulate over multiple loading and unloading cycles, leading to clinical deep tissues ulceration. Copyright © 2011 Elsevier Ltd. All rights reserved.

Turtle anoxia tolerance: Biochemistry and gene regulation.

PubMed

Krivoruchko, Anastasia; Storey, Kenneth B

2015-06-01

While oxygen limitation can be extremely damaging for many animals, some vertebrates have perfected anaerobic survival. Freshwater turtles belonging to the Trachemys and Chrysemys genera, for example, can survive many weeks without oxygen, and as such are commonly used as model animals for vertebrate anoxia tolerance. In the present review we discuss the recent advances made in understanding the biochemical and molecular nature of natural anoxia tolerance of freshwater turtles. Research in recent years has shown that activation of several important pathways occurs in response to anoxia in turtles, including those that function in the stress response, cell cycle arrest, inhibition of gene expression and metabolism. These likely contribute to anoxia tolerance in turtle tissues by minimizing cell damage in response to anoxia, as well as facilitating metabolic rate depression. The research discussed in the present review contributes to the understanding of how freshwater turtles can survive without oxygen for prolonged periods of time. This could also improve understanding of the molecular nature of hypoxic/ischemic injuries in mammalian tissues and suggest potential ways to avoid these. Copyright © 2015 Elsevier B.V. All rights reserved.

Contrast medium extravasation injury: guidelines for prevention and management.

PubMed

Bellin, Marie-France; Jakobsen, Jarl A; Tomassin, Isabelle; Thomsen, Henrik S; Morcos, Sameh K; Thomsen, H S; Morcos, S K; Almén, T; Aspelin, P; Bellin, M F; Clauss, W; Flaten, H; Grenier, N; Ideé, J-M; Jakobsen, J A; Krestin, G P; Stacul, F; Webb, J A W

2002-11-01

Extravasation of contrast material is a well-recognized complication of contrast-enhanced imaging studies. The management of this complication is contentious; therefore, the Contrast Media Safety Committee of The European Society of Urogenital Radiology decided to review the literature and issue guidelines. A comprehensive literature search was carried out. The resulting report was discussed at the 8th European Symposium on Urogenital Radiology in Genoa, Italy. Automated power injection may result in extravasation of large volumes and may or can lead to severe tissue damage. Infants, young children and unconscious and debilitated patients are particularly at risk of extravasation during contrast media injection. Fortunately, most extravasations result in minimal swelling or erythema, with no long-term sequelae; however, severe skin necrosis and ulceration may occur. Large volumes of high osmolar contrast media are known to induce significant tissue damage. Compartment syndrome may be seen associated with extravasation of large volumes. Conservative management is often adequate, but in serious cases the advice of a plastic surgeon is recommended. Based on the review simple guidelines for prophylaxis and management of contrast medium extravasation injuries are proposed.

Modeling of endoluminal and interstitial ultrasound hyperthermia and thermal ablation: applications to device design, feedback control, and treatment planning

PubMed Central

Prakash, Punit; Salgaonkar, Vasant A.; Diederich, Chris J.

2014-01-01

Endoluminal and catheter-based ultrasound applicators are currently under development and are in clinical use for minimally invasive hyperthermia and thermal ablation of various tissue targets. Computational models play a critical role in in device design and optimization, assessment of therapeutic feasibility and safety, devising treatment monitoring and feedback control strategies, and performing patient-specific treatment planning with this technology. The critical aspects of theoretical modeling, applied specifically to endoluminal and interstitial ultrasound thermotherapy, are reviewed. Principles and practical techniques for modeling acoustic energy deposition, bioheat transfer, thermal tissue damage, and dynamic changes in the physical and physiological state of tissue are reviewed. The integration of these models and applications of simulation techniques in identification of device design parameters, development of real time feedback-control platforms, assessing the quality and safety of treatment delivery strategies, and optimization of inverse treatment plans are presented. PMID:23738697

Intraluminal tissue welding for anastomosis

DOEpatents

Glinsky, M.; London, R.; Zimmerman, G.; Jacques, S.

1998-10-27

A method and device are provided for performing intraluminal tissue welding for anastomosis of a hollow organ. A retractable catheter assembly is delivered through the hollow organ and consists of a catheter connected to an optical fiber, an inflatable balloon, and a biocompatible patch mounted on the balloon. The disconnected ends of the hollow organ are brought together on the catheter assembly, and upon inflation of the balloon, the free ends are held together on the balloon to form a continuous channel while the patch is deployed against the inner wall of the hollow organ. The ends are joined or ``welded`` using laser radiation transmitted through the optical fiber to the patch. A thin layer of a light-absorbing dye on the patch can provide a target for welding. The patch may also contain a bonding agent to strengthen the bond. The laser radiation delivered has a pulse profile to minimize tissue damage. 8 figs.

Intraluminal tissue welding for anastomosis

DOEpatents

Glinsky, Michael; London, Richard; Zimmerman, George; Jacques, Steven

1998-10-27

A method and device are provided for performing intraluminal tissue welding for anastomosis of a hollow organ. A retractable catheter assembly is delivered through the hollow organ and consists of a catheter connected to an optical fiber, an inflatable balloon, and a biocompatible patch mounted on the balloon. The disconnected ends of the hollow organ are brought together on the catheter assembly, and upon inflation of the balloon, the free ends are held together on the balloon to form a continuous channel while the patch is deployed against the inner wall of the hollow organ. The ends are joined or "welded" using laser radiation transmitted through the optical fiber to the patch. A thin layer of a light-absorbing dye on the patch can provide a target for welding. The patch may also contain a bonding agent to strengthen the bond. The laser radiation delivered has a pulse profile to minimize tissue damage.

Autotransplantation donor tooth site harvesting using piezosurgery.

PubMed

Ylikontiola, Leena P; Sándor, George K

2016-01-01

The harvesting of a tooth as a candidate for tooth autotransplantation requires that the delicate dental tissues around the tooth be minimally traumatized. This is especially so for the periradicular tissues of the tooth root and the follicular tissues surrounding the crown. The aim of this report is to describe the use of piezosurgery as an attempt at morbidity reduction in the harvesting of teeth for autotransplantation. A piezosurgical handpiece and its selection of tips were easily adapted to allow the harvesting and delivery of teeth for autotransplantation purposes. Twenty premolar teeth were harvested using a piezosurgical device. The harvested teeth were subsequently successfully autotransplanted. All twenty teeth healed in a satisfactory manner without excessive mobility or ankyloses. Piezosurgery avoids some of the traumatic aspects of harvesting teeth and removing bone which are associated with thermal damage from the use of conventional rotary instruments or saws. Piezosurgery can be adapted to facilitate the predictable harvesting of teeth for autotransplantation purposes.

Er:YAG laser-assisted hair transplantation in cicatricial alopecia.

PubMed

Podda, M; Spieth, K; Kaufmann, R

2000-11-01

Autologous hair transplantation and its combination with flap or reduction procedures is a common surgical approach to cover defects in cicatricial alopecias. Due to the poor recipient conditions present in scar tissue, it is crucial to minimize the trauma exerted on implantation holes in order to achieve good transplantation results. We sought to evaluate the "cold"-ablative properties of the Er:YAG laser for the generation of recipient holes in cicatricial alopecia. Patients with cicatricial alopecia of diverse etiology were treated with Er:YAG laser-assisted hair transplantation. Mini- or micrografts were inserted into recipient holes ablated with a pulse energy of 900-1200 mJ and a spot size of 1.0-1.6 mm. A fluence of 80-120 J/cm2 and 8-12 pulses gave an almost ideal combination of minimal thermal damage and tissue ablation down to the subcutis. With an apparent mini- and micrograft survival of 95% we achieved good cosmetic results after two to five transplant sessions in all patients. The Er:YAG laser is a novel effective tool to ablate recipient holes for autologous hair transplantation in cicatricial alopecia.

The efficacy of laser surgery for verruca plantaris: report of a study.

PubMed

Lavery, L A; Cutler, J M; Galinski, A W; Gastwirth, B W

1988-04-01

Many therapeutic modalities are available to eradicate plantar verrucae. Lately, lasers have gained a great deal of notoriety in the treatment of verrucae. In this study, we chose to evaluate the success of using one laser treatment for full eradication of verrucae. The results indicated that the greatest success rate occurred with solitary lesions. Other studies of methods of verrucae treatment yielded similar results to those of the laser, with cryotherapy achieving the highest success rate. However, the higher rate was based on an average of two treatments, whereas this study obtained similar results with just one. The laser also has the advantages of minimal postoperative pain, minimal healing time, and less damage to perilesional tissue. These advantages make the laser a viable option in the treatment of verrucae plantaris.

Measurement of cell death by oxidative stress in three-dimensional spheroids from trophoblast and in fragments of decidua tissue.

PubMed

Theuerkauf, Regine-Susanne; Ahammer, Helmut; Siwetz, Monika; Helige, Christine; Dohr, Gottfried; Walcher, Wolfgang; Palacio, José Ramón; Martinez, Paz; Sedlmayr, Peter

2010-05-01

We report a new morphometric method for measurement of the amount of cell death in three-dimensional multicellular spheroids of the trophoblast-like cell line AC1-M59 and of cultured pieces of decidua tissue (decidua spheroids) in response to a cytotoxic agent. The viability of the spheroids was assessed by adding propidium iodide to the culture medium at the end of the toxic treatment. On fluorescence and brightfield images of serial cryosections the areas of propidium iodide fluorescence and the entire corresponding spheroids were measured by applying digital image processing and ratiometrical quantification. As an example, we evaluated the cytotoxic effect of hydrogen peroxide on both types of spheroids. The relative potency of hydrogen peroxide to induce tissue damage was assessed quantitatively for determination of the minimal concentration that leads to an increase in cytotoxicity. The method presented suggests general applicability for in vitro determination of toxicity against tissues. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Re-introducing honey in the management of wounds and ulcers - theory and practice.

PubMed

Molan, Peter C

2002-11-01

Dressing wounds with honey, a standard practice in past times, went out of fashion when antibiotics came into use. Because antibiotic-resistant bacteria have become a widespread clinical problem, a renaissance in honey use has occurred. Laboratory studies and clinical trials have shown that honey is an effective broad-spectrum antibacterial agent that has no adverse effects on wound tissues. As well as having an antibacterial action, honey also provides rapid autolytic debridement, deodorizes wounds, and stimulates the growth of wound tissues to hasten healing and start the healing process in dormant wounds. Its anti-inflammatory activity rapidly reduces pain, edema, and exudate and minimizes hypertrophic scarring. It also provides a moist healing environment for wound tissues with no risk of maceration of surrounding skin and completely prevents adherence of dressings to the wound bed so no pain or tissue damage is associated with dressing changes. Using appropriate dressing practice overcomes potential messiness and handling problems.

Reproducibility of Ultrasound-Guided High Intensity Focused Ultrasound (HIFU) Thermal Lesions in Minimally-Invasive Brain Surgery

NASA Astrophysics Data System (ADS)

Zahedi, Sulmaz

This study aims to prove the feasibility of using Ultrasound-Guided High Intensity Focused Ultrasound (USg-HIFU) to create thermal lesions in neurosurgical applications, allowing for precise ablation of brain tissue, while simultaneously providing real time imaging. To test the feasibility of the system, an optically transparent HIFU compatible tissue-mimicking phantom model was produced. USg-HIFU was then used for ablation of the phantom, with and without targets. Finally, ex vivo lamb brain tissue was imaged and ablated using the USg-HIFU system. Real-time ultrasound images and videos obtained throughout the ablation process showing clear lesion formation at the focal point of the HIFU transducer. Post-ablation gross and histopathology examinations were conducted to verify thermal and mechanical damage in the ex vivo lamb brain tissue. Finally, thermocouple readings were obtained, and HIFU field computer simulations were conducted to verify findings. Results of the study concluded reproducibility of USg-HIFU thermal lesions for neurosurgical applications.

NaGdF4:Nd3+/Yb3+ Nanoparticles as Multimodal Imaging Agents

NASA Astrophysics Data System (ADS)

Pedraza, Francisco; Rightsell, Chris; Kumar, Ga; Giuliani, Jason; Monton, Car; Sardar, Dhiraj

Medical imaging is a fundamental tool used for the diagnosis of numerous ailments. Each imaging modality has unique advantages; however, they possess intrinsic limitations. Some of which include low spatial resolution, sensitivity, penetration depth, and radiation damage. To circumvent this problem, the combination of imaging modalities, or multimodal imaging, has been proposed, such as Near Infrared Fluorescence imaging (NIRF) and Magnetic Resonance Imaging (MRI). Combining individual advantages, specificity and selectivity of NIRF with the deep penetration and high spatial resolution of MRI, it is possible to circumvent their shortcomings for a more robust imaging technique. In addition, both imaging modalities are very safe and minimally invasive. Fluorescent nanoparticles, such as NaGdF4:Nd3 +/Yb3 +, are excellent candidates for NIRF/MRI multimodal imaging. The dopants, Nd and Yb, absorb and emit within the biological window; where near infrared light is less attenuated by soft tissue. This results in less tissue damage and deeper tissue penetration making it a viable candidate in biological imaging. In addition, the inclusion of Gd results in paramagnetic properties, allowing their use as contrast agents in multimodal imaging. The work presented will include crystallographic results, as well as full optical and magnetic characterization to determine the nanoparticle's viability in multimodal imaging.

[Changes in clinical indices in patients in predisposition for pathological cicatrices formation].

PubMed

Avetikov, D S; Skrypnyk, V M; Pronina, O M; Stavyts'kyĭ, S O; Boĭko, I V

2015-01-01

Prophylaxis of ocurrence of pathological cutaneous cicatrices is one of actual problems of plastic surgery of head and neck. Cicatricial changes of tissues, as a consequence of operative interventions and various damaging causes (mechanical, thermal and chemical impact, ionizing irradiation, deep destructive inflammation), were depicted. Propensity for formation of pathological cicatrices we consider as the organism state, in which cicatricial changes occur as an answer for minimal trauma or spontaneously. Detailed analysis of fundamental issues and periodical scientific publications witness the insufficient substantiation of this issue.

[Advantages and disadvantages of endocrown restorations of endodontically treated teeth with large coronal destruction].

PubMed

Bao, X D

2018-04-09

The strength of endodontically treated teeth were reduced apparently because of structural damage, therefore further reduction of healthy tissue should be avoided as much as possible in restoration. Endocrown made by chair-side CAD/CAM is some kind of minimal invasive restoration, and the retention of restoration is achieved by reliable bonding and macromechanial retention forces. Without post preparation, the root structure could be resevered. Following the indications and use of biomechanical dentin-like CAD/CAM materials could reduce the adverse effect of tensile stress on cervical part.

Tissue Damage Signaling Is a Prerequisite for Protective Neutrophil Recruitment to Microbial Infection in Zebrafish.

PubMed

Huang, Cong; Niethammer, Philipp

2018-05-15

Tissue damage and infection are deemed likewise triggers of innate immune responses. But whereas neutrophil responses to microbes are generally protective, neutrophil recruitment into damaged tissues without infection is deleterious. Why neutrophils respond to tissue damage and not just to microbes is unknown. Is it a flaw of the innate immune system that persists because evolution did not select against it, or does it provide a selective advantage? Here we dissect the contribution of tissue damage signaling to antimicrobial immune responses in a live vertebrate. By intravital imaging of zebrafish larvae, a powerful model for innate immunity, we show that prevention of tissue damage signaling upon microbial ear infection abrogates leukocyte chemotaxis and reduces animal survival, at least in part, through suppression of cytosolic phospholipase A 2 (cPla 2 ), which integrates tissue damage- and microbe-derived cues. Thus, microbial cues are insufficient, and damage signaling is essential for antimicrobial neutrophil responses in zebrafish. Copyright © 2018 Elsevier Inc. All rights reserved.

Optimized heterologous transfection of viable adult organotypic brain slices using an enhanced gene gun

PubMed Central

2013-01-01

Background Organotypic brain slices (OTBS) are an excellent experimental compromise between the facility of working with cell cultures and the biological relevance of using animal models where anatomical, morphological, and cellular function of specific brain regions can be maintained. The biological characteristics of OTBS can subsequently be examined under well-defined conditions. They do, however, have a number of limitations; most brain slices are derived from neonatal animals, as it is difficult to properly prepare and maintain adult OTBS. There are ample problems with tissue integrity as OTBS are delicate and frequently become damaged during the preparative stages. Notwithstanding these obstacles, the introduced exogenous proteins into both neuronal cells, and cells imbedded within tissues, have been consistently difficult to achieve. Results Following the ex vivo extraction of adult mouse brains, mounted inside a medium-agarose matrix, we have exploited a precise slicing procedure using a custom built vibroslicer. To transfect these slices we used an improved biolistic transfection method using a custom made low-pressure barrel and novel DNA-coated nanoparticles (40 nm), which are drastically smaller than traditional microparticles. These nanoparticles also minimize tissue damage as seen by a significant reduction in lactate dehydrogenase activity as well as propidium iodide (PI) and dUTP labelling compared to larger traditional gold particles used on these OTBS. Furthermore, following EYFP exogene delivery by gene gun, the 40 nm treated OTBS displayed a significantly larger number of viable NeuN and EYFP positive cells. These OTBS expressed the exogenous proteins for many weeks. Conclusions Our described methodology of producing OTBS, which results in better reproducibility with less tissue damage, permits the exploitation of mature fully formed adult brains for advanced neurobiological studies. The novel 40 nm particles are ideal for the viable biolistic transfection of OTBS by reducing tissue stress while maintaining long term exogene expression. PMID:24354851

Effects of heat transfer and energy absorption in the ablation of biological tissues by pulsetrain-burst (>100 MHz) ultrafast laser processing

NASA Astrophysics Data System (ADS)

Forrester, Paul; Bol, Kieran; Lilge, Lothar; Marjoribanks, Robin

2006-09-01

Energy absorption and heat transfer are important factors for regulating the effects of ablation of biological tissues. Heat transfer to surrounding material may be desirable when ablating hard tissue, such as teeth or bone, since melting can produce helpful material modifications. However, when ablating soft tissue it is important to minimize heat transfer to avoid damage to healthy tissue - for example, in eye refractive surgery (e.g., Lasik), nanosecond pulses produce gross absorption and heating in tissue, leading to shockwaves, which kill and thin the non-replicating epithelial cells on the inside of the cornea; ultrafast pulses are recognized to reduce this effect. Using a laser system that delivers 1ps pulses in 10μs pulsetrains at 133MHz we have studied a range of heat- and energy-transfer effects on hard and soft tissue. We describe the ablation of tooth dentin and enamel under various conditions to determine the ablation rate and chemical changes that occur. Furthermore, we characterize the impact of pulsetrain-burst treatment of collagen-based tissue to determine more efficient methods of energy transfer to soft tissues. By studying the optical science of laser tissue interaction we hope to be able to make qualitative improvements to medical treatments using lasers.

Minimizing damage to a propped fracture by controlled flowback procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robinson, B.M.; Holditch, S.A.; Whitehead, W.S.

1988-06-01

Severe fracture-conductivity damage can result from proppant crushing and/or proppant flowback into the wellbore. Such damage is often concentrated near the wellbore and can directly affect postfracture performance. Most of the time severe fracture-conductivity damage can be minimized by choosing the correct type of proppant for a particular well. In many cases, however, this is not enough. To minimize excessive crushing or to prevent proppant flowback, it is also necessary to control carefully the flowback of the well after the treatment. Specific procedures can be followed to minimize severe fracture-conductivity damage. These procedures involve controlling the rates at which loadmore » fluids are recovered and maximizing backpressure against the formation. These procedures require much more time and effort than is normally spent on postfracture cleanup; however, the efforts could result in better performance.« less

Abnormal permeability of inner and outer mitochondrial membranes contributes independently to mitochondrial dysfunction in the liver during acute endotoxemia.

PubMed

Crouser, Elliott D; Julian, Mark W; Huff, Jennifer E; Joshi, Mandar S; Bauer, John A; Gadd, Martha E; Wewers, Mark D; Pfeiffer, Douglas R

2004-02-01

This study was designed to determine the role played by the mitochondrial permeability transition in the pathogenesis of mitochondrial damage and dysfunction in a representative systemic organ during the acute phase of endotoxemia. A well-established, normotensive feline model was employed to determine whether pretreatment with cyclosporine A, a potent inhibitor of the mitochondrial permeability transition, normalizes mitochondrial ultrastructural injury and dysfunction in the liver during acute endotoxemia. The Ohio State University Medical Center research laboratory. Random source, adult, male conditioned cats. Hemodynamic resuscitation and maintenance of acid-base balance and tissue oxygen availability were provided, as needed, to minimize the potentially confounding effects of tissue hypoxia and/or acidosis on the experimental results. Treatment groups received isotonic saline vehicle (control; n = 6), lipopolysaccharide (3.0 mg/kg, intravenously; n = 8), or cyclosporine A (6.0 mg/kg, intravenously; n = 6) or tacrolimus (FK506, 0.1 mg/kg, intravenously; n = 4) followed in 30 mins by lipopolysaccharide (3.0 mg/kg, intravenously). Liver samples were obtained 4 hrs posttreatment, and mitochondrial ultrastructure, function, and cytochrome c, Bax, and ceramide contents were assessed. As expected, significant mitochondrial injury was apparent in the liver 4 hrs after lipopolysaccharide treatment, despite maintenance of regional tissue oxygen availability. Namely, mitochondria demonstrated high-amplitude swelling and exhibited altered respiratory function. Cyclosporine A pretreatment attenuated lipopolysaccharide-induced mitochondrial ultrastructural abnormalities and normalized mitochondrial respiratory control, reflecting protection against inner mitochondrial membrane damage. However, an abnormal permeability of outer mitochondrial membranes to cytochrome c was observed in all lipopolysaccharide-treated groups and was associated with increased mitochondrial concentrations of Bax and ceramide. These studies confirm that liver mitochondria are early targets of injury during endotoxemia and that inner and outer mitochondrial membrane damage occurs through different mechanisms. Inner mitochondrial membrane damage appears to relate to the mitochondrial permeability transition, whereas outer mitochondrial membrane damage can occur independent of the mitochondrial permeability transition. Preliminary evidence suggests that Bax may participate in lipopolysaccharide-induced outer mitochondrial membrane damage, but further investigations are needed to confirm this.

Multifunctional transducer

NASA Technical Reports Server (NTRS)

Feldstein, C.; Lewis, G. W.; Culler, V. H.; Merrbaum, S. (Inventor)

1981-01-01

Several parameters of a small region of a muscle tissue or other object, can be simultaneously measured using with minimal traumatizing or damage of the object, a trifunctional transducer which can determine the force applied by a muscle fiber, the displacement of the fiber, and the change in thickness of the fiber. The transducer has three legs with inner ends joined together and outer ends formed to piece the tissue and remain within it. Two of the legs are relatively stiff, to measure force applied by the tissue, and a third leg is relatively flexible to measure displacement of the tissue relative to one or both stiff legs, and with the three legs lying in a common plane so that the force and displacement measurements all relate to the same direction of muscle movements. A flexible loop is attached to one of the stiff legs to measure changes in muscle thickness, with the upper end of the loop fixed to the leg and the lower end of the loop bearing against the surface of the tissue and being free to slide on the leg.

Continuum theory of fibrous tissue damage mechanics using bond kinetics: application to cartilage tissue engineering.

PubMed

Nims, Robert J; Durney, Krista M; Cigan, Alexander D; Dusséaux, Antoine; Hung, Clark T; Ateshian, Gerard A

2016-02-06

This study presents a damage mechanics framework that employs observable state variables to describe damage in isotropic or anisotropic fibrous tissues. In this mixture theory framework, damage is tracked by the mass fraction of bonds that have broken. Anisotropic damage is subsumed in the assumption that multiple bond species may coexist in a material, each having its own damage behaviour. This approach recovers the classical damage mechanics formulation for isotropic materials, but does not appeal to a tensorial damage measure for anisotropic materials. In contrast with the classical approach, the use of observable state variables for damage allows direct comparison of model predictions to experimental damage measures, such as biochemical assays or Raman spectroscopy. Investigations of damage in discrete fibre distributions demonstrate that the resilience to damage increases with the number of fibre bundles; idealizing fibrous tissues using continuous fibre distribution models precludes the modelling of damage. This damage framework was used to test and validate the hypothesis that growth of cartilage constructs can lead to damage of the synthesized collagen matrix due to excessive swelling caused by synthesized glycosaminoglycans. Therefore, alternative strategies must be implemented in tissue engineering studies to prevent collagen damage during the growth process.

Continuum theory of fibrous tissue damage mechanics using bond kinetics: application to cartilage tissue engineering

PubMed Central

Nims, Robert J.; Durney, Krista M.; Cigan, Alexander D.; Hung, Clark T.; Ateshian, Gerard A.

2016-01-01

This study presents a damage mechanics framework that employs observable state variables to describe damage in isotropic or anisotropic fibrous tissues. In this mixture theory framework, damage is tracked by the mass fraction of bonds that have broken. Anisotropic damage is subsumed in the assumption that multiple bond species may coexist in a material, each having its own damage behaviour. This approach recovers the classical damage mechanics formulation for isotropic materials, but does not appeal to a tensorial damage measure for anisotropic materials. In contrast with the classical approach, the use of observable state variables for damage allows direct comparison of model predictions to experimental damage measures, such as biochemical assays or Raman spectroscopy. Investigations of damage in discrete fibre distributions demonstrate that the resilience to damage increases with the number of fibre bundles; idealizing fibrous tissues using continuous fibre distribution models precludes the modelling of damage. This damage framework was used to test and validate the hypothesis that growth of cartilage constructs can lead to damage of the synthesized collagen matrix due to excessive swelling caused by synthesized glycosaminoglycans. Therefore, alternative strategies must be implemented in tissue engineering studies to prevent collagen damage during the growth process. PMID:26855751

Fatigue Damage of Collagenous Tissues: Experiment, Modeling and Simulation Studies

PubMed Central

Martin, Caitlin; Sun, Wei

2017-01-01

Mechanical fatigue damage is a critical issue for soft tissues and tissue-derived materials, particularly for musculoskeletal and cardiovascular applications; yet, our understanding of the fatigue damage process is incomplete. Soft tissue fatigue experiments are often difficult and time-consuming to perform, which has hindered progress in this area. However, the recent development of soft-tissue fatigue-damage constitutive models has enabled simulation-based fatigue analyses of tissues under various conditions. Computational simulations facilitate highly controlled and quantitative analyses to study the distinct effects of various loading conditions and design features on tissue durability; thus, they are advantageous over complex fatigue experiments. Although significant work to calibrate the constitutive models from fatigue experiments and to validate predictability remains, further development in these areas will add to our knowledge of soft-tissue fatigue damage and will facilitate the design of durable treatments and devices. In this review, the experimental, modeling, and simulation efforts to study collagenous tissue fatigue damage are summarized and critically assessed. PMID:25955007

Vesicant extravasation part II: Evidence-based management and continuing controversies.

PubMed

Wickham, Rita; Engelking, Constance; Sauerland, Carmel; Corbi, Dominick

2006-11-27

To review the literature, synthesize current recommendations, and discuss remaining controversies regarding vesicant extravasation management. Published evidence-based reports, clinical articles, and anecdotal case reports about antineoplastic and nonantineoplastic vesicant agent management. Prevention of vesicant extravasation sequelae requires knowledge about vesicant extravasation manifestations and differentiation of vesicant extravasation from other local IV site reactions. When evidence is weak or missing, logical application of data-based or empirical management strategies is critical. Actions may include timely administration of subcutaneous or topical antidotes, comfort measures, and surgical interventions to minimize the extent of tissue damage and morbidity should extravasation occur. Vesicant extravasation and sequelae constitute a complex patient problem. Clinicians should strive to prevent extravasation or seek to minimize injury should it occur. To this end, clinicians must demonstrate awareness of its risks and use specialized knowledge when administering vesicant agents. Nurses who administer vesicant agents should understand the nursing and collaborative actions that should be taken to minimize patient morbidity, pain, and disability.

The effects of different fractions of Coriandrum sativum on pentylenetetrazole-induced seizures and brain tissues oxidative damage in rats

PubMed Central

Anaeigoudari, Akbar; Hosseini, Mahmoud; Karami, Reza; Vafaee, Farzaneh; Mohammadpour, Toktam; Ghorbani, Ahmad; Sadeghnia, Hamid Reza

2016-01-01

Objective: In the present work, the effects of different fractions of Coriandrum sativum (C. sativum), on pentylenetetrazole (PTZ)-induced seizures and brain tissues oxidative damage were investigated in rats. Materials and Methods: The rats were divided into the following groups: (1) vehicle, (2) PTZ (90 mg/kg), (3) water fraction (WF) of C. sativum (25 and 100 mg/kg), (4) n-butanol fraction (NBF) of C. sativum (25 and 100 mg/kg), and (5) ethyl acetate fraction (EAF) of C. sativum (25 and 100 mg/kg). Results: The first generalized tonic-clonic seizures (GTCS) latency in groups treated with 100 mg /kg of WF or EAF was significantly higher than that of PTZ group (p<0.01). In contrast to WF, the EAF and NBF were not effective in increasing the first minimal clonic seizure (MCS) latency. Malondialdehyde (MDA) levels in both cortical and hippocampal tissues of PTZ group were significantly higher than those of control animals (p<0.001). Pretreatment with WF, NBF, or EAF resulted in a significant reduction in the MDA levels of hippocampi (p<0.01 - p<0.001). Following PTZ administration, a significant reduction in total thiol groups was observed in the brain tissues (p<0.05). Pretreatment with WF and NBF significantly elevated thiol concentrations in cortical and hippocampal tissues, respectively (p<0.05). Conclusion: The present study showed that different fractions of C. sativum possess antioxidant activity in the brain and WF and EAF of this plant have anticonvulsant effects. PMID:27222836

Frozen tissue preparation for high-resolution multiplex histological analyses of human brain specimens.

PubMed

Shao, Fangjie; Jiang, Wenhong; Gao, Qingqing; Li, Baizhou; Sun, Chongran; Wang, Qiyuan; Chen, Qin; Sun, Bing; Shen, Hong; Zhu, Keqing; Zhang, Jianmin; Liu, Chong

2017-10-01

The availability of a comprehensive tissue library is essential for elucidating the function and pathology of human brains. Considering the irreplaceable status of the formalin-fixation-paraffin-embedding (FFPE) preparation in routine pathology and the advantage of ultra-low temperature to preserve nucleic acids and proteins for multi-omics studies, these methods have become major modalities for the construction of brain tissue libraries. Nevertheless, the use of FFPE and snap-frozen samples is limited in high-resolution histological analyses because the preparation destroys tissue integrity and/or many important cellular markers. To overcome these limitations, we detailed a protocol to prepare and analyze frozen human brain samples that is particularly suitable for high-resolution multiplex immunohistological studies. As an alternative, we offered an optimized procedure to rescue snap-frozen tissues for the same purpose. Importantly, we provided a guideline to construct libraries of frozen tissue with minimal effort, cost and space. Taking advantage of this new tissue preparation modality to nicely preserve the cellular information that was otherwise damaged using conventional methods and to effectively remove tissue autofluorescence, we described the high-resolution landscape of the cellular composition in both lower-grade gliomas and glioblastoma multiforme samples. Our work showcases the great value of fixed frozen tissue in understanding the cellular mechanisms of CNS functions and abnormalities.

Treatment of epulis fissuratum with CO2 laser and prosthetic rehabilitation in patients with vesiculobullous disease.

PubMed

Işeri, Ufuk; Ozçakir-Tomruk, Ceyda; Gürsoy-Mert, Hare

2009-08-01

The purpose of this article is the clinical presentation of the treatment of epulis fissuratum with CO(2) laser and prosthetic rehabilitation of three patients with vesiculobullous diseases (VBDs). Oral problems such as blister formation with minimal trauma are usually encountered in the VBDs. With repeated cycles of blistering and healing, oral hygiene is usually compromised, which leads to rapid breakdown of the dentition. Prosthetic rehabilitation includes complete, partial, and implant-supported dentures; however, ill-fitting dentures can cause inflammatory fibrous hyperplasia. Clinical application of CO(2) laser has been recommended to treat benign oral lesions such as epulis fissuratum and fibroma. The treatment plan consisted of excision of fibrous tissues, controlling dental plaque, and prosthetic rehabilitation. The excision of fibrous tissue was performed with CO(2) laser, and the wounds formed by laser were left open to secondary epithelization. The dental plaque and calculus deposits were cleaned with ultrasonic scalers and a well-formed acrylic denture for maxilla and mandible were fabricated after a month. There was no recurrent fibrous tissue formation at 1 year follow-up. However, plaque accumulation control was unsatisfactory and the patients were therefore urged to undergo a regular 6-month preventive dental prophylaxis regimen and denture re-evaluation. The CO(2) laser may be a useful instrument in the treatment of soft tissue pathologies in VBDs patients due to minimal damage to surrounding tissue. Use of complete or partial dentures has been considered a practical, economic, and nonsurgical treatment option for patients who have been diagnosed with VBDs.

Precise femtosecond laser ablation of dental hard tissue: preliminary investigation on adequate laser parameters

NASA Astrophysics Data System (ADS)

Hikov, Todor; Pecheva, Emilia; Montgomery, Paul; Antoni, Frederic; Leong-Hoi, Audrey; Petrov, Todor

2017-01-01

This work aims at evaluating the possibility of introducing state-of-the-art commercial femtosecond laser system in restorative dentistry by maintaining well-known benefits of lasers for caries removal, but also in overcoming disadvantages such as thermal damage of irradiated substrate. Femtosecond ablation of dental hard tissue is investigated by changing the irradiation parameters (pulsed laser energy, scanning speed and pulse repetition rate), assessed for enamel and dentin. The femtosecond laser system used in this work may be suitable for cavity preparation in dentin and enamel, due to the expected effective ablation and low temperature increase when using ultra short laser pulses. If adequate laser parameters are selected, this system seems to be promising for promoting a laser-assisted, minimally invasive approach in restorative dentistry.

Recent advances in targeted endoscopic imaging: Early detection of gastrointestinal neoplasms

PubMed Central

Kwon, Yong-Soo; Cho, Young-Seok; Yoon, Tae-Jong; Kim, Ho-Shik; Choi, Myung-Gyu

2012-01-01

Molecular imaging has emerged as a new discipline in gastrointestinal endoscopy. This technology encompasses modalities that can visualize disease-specific morphological or functional tissue changes based on the molecular signature of individual cells. Molecular imaging has several advantages including minimal damage to tissues, repetitive visualization, and utility for conducting quantitative analyses. Advancements in basic science coupled with endoscopy have made early detection of gastrointestinal cancer possible. Molecular imaging during gastrointestinal endoscopy requires the development of safe biomarkers and exogenous probes to detect molecular changes in cells with high specificity anda high signal-to-background ratio. Additionally, a high-resolution endoscope with an accurate wide-field viewing capability must be developed. Targeted endoscopic imaging is expected to improve early diagnosis and individual therapy of gastrointestinal cancer. PMID:22442742

Electro-gene transfer to skin using a noninvasive multielectrode array

PubMed Central

Guo, Siqi; Donate, Amy; Basu, Gaurav; Lundberg, Cathryn; Heller, Loree; Heller, Richard

2011-01-01

Because of its large surface area and easy access for both delivery and monitoring, the skin is an attractive target for gene therapy for cutaneous diseases, vaccinations and several metabolic disorders. The critical factors for DNA delivery to the skin by electroporation (EP) are effective expression levels and minimal or no tissue damage. Here, we evaluated the non-invasive multielectrode array (MEA) for gene electrotransfer. For these studies we utilized a guinea pig model, which has been shown to have a similar thickness and structure to human skin. Our results demonstrate significantly increased gene expression 2 to 3 logs above injection of plasmid DNA alone over 15 days. Furthermore, gene expression could be enhanced by increasing the size of the treatment area. Transgene expressing cells were observed exclusively in the epidermal layer of the skin. In contrast to caliper or plate electrodes, skin EP with the MEA greatly reduced muscle twitching and resulted in minimal and completely recoverable skin damage. These results suggest EP with the MEA can be an efficient and non-invasive skin delivery method with less adverse side effects than other EP delivery systems and promising clinical applications. PMID:21262290

Skin suturing and cortical surface viral infusion improves imaging of neuronal ensemble activity with head-mounted miniature microscopes.

PubMed

Li, Xinjian; Cao, Vania Y; Zhang, Wenyu; Mastwal, Surjeet S; Liu, Qing; Otte, Stephani; Wang, Kuan Hong

2017-11-01

In vivo optical imaging of neural activity provides important insights into brain functions at the single-cell level. Cranial windows and virally delivered calcium indicators are commonly used for imaging cortical activity through two-photon microscopes in head-fixed animals. Recently, head-mounted one-photon microscopes have been developed for freely behaving animals. However, minimizing tissue damage from the virus injection procedure and maintaining window clarity for imaging can be technically challenging. We used a wide-diameter glass pipette at the cortical surface for infusing the viral calcium reporter AAV-GCaMP6 into the cortex. After infusion, the scalp skin over the implanted optical window was sutured to facilitate postoperative recovery. The sutured scalp was removed approximately two weeks later and a miniature microscope was attached above the window to image neuronal activity in freely moving mice. We found that cortical surface virus infusion efficiently labeled neurons in superficial layers, and scalp skin suturing helped to maintain the long-term clarity of optical windows. As a result, several hundred neurons could be recorded in freely moving animals. Compared to intracortical virus injection and open-scalp postoperative recovery, our methods minimized tissue damage and dura overgrowth underneath the optical window, and significantly increased the experimental success rate and the yield of identified neurons. Our improved cranial surgery technique allows for high-yield calcium imaging of cortical neurons with head-mounted microscopes in freely behaving animals. This technique may be beneficial for other optical applications such as two-photon microscopy, multi-site imaging, and optogenetic modulation. Published by Elsevier B.V.

The role of neutrophils in injury and repair following muscle stretch

PubMed Central

Toumi, Hechmi; F'guyer, Sleem; Best, Thomas M

2006-01-01

Stretch injury to the myotendinous junction is a common problem in competitive athletes and those involved in regular physical activity. The major risk factor for recurrent injury appears to be the primary injury itself. Physicians, physical therapists, athletic trainers and athletes alike continue to search for optimal treatment and prevention strategies. Acute inflammation is regarded as the body's generalized protective response to tissue injury. An especially important and unexplored aspect of inflammation following injury is the role of inflammatory cells in extending injury and possibly directing muscle repair. It has been suggested that the inflammatory reaction, although it typically represents a reaction to damage and necrosis, may even bring about some local damage of its own and therefore increase the possibility for scarring and fibrosis. Limiting certain aspects of inflammation may theoretically reduce muscle damage as well as signals for muscle scarring. Here we focus on the role of neutrophils in injury and repair of stretch-injured skeletal muscle. A minimally invasive model that generates a reproducible injury to rabbit skeletal muscle is presented. We present a plausible theory that neutrophil-derived oxidants resulting from the initial stretch injury are responsible for extending the damage. An anti-CD11b antibody that blocks the neutrophil's respiratory burst is employed to reduce myofibre damage. An intriguing area that is currently being explored in our laboratory and others is the potential role for neutrophils to contribute to muscle growth and repair. It may be possible that neutrophils facilitate muscle repair through removal of tissue debris as well as by activation of satellite cells. Recent and ongoing investigations point to interleukin-6 as a possible key cytokine in muscle inflammation and repair. Studies to elucidate a clearer understanding of this possibility will be reviewed. PMID:16637872

Intravital imaging of the immune responses during liver-stage malaria infection: An improved approach for fixing the liver.

PubMed

Akbari, Masoud; Kimura, Kazumi; Houts, James T; Yui, Katsuyuki

2016-10-01

The host-parasite relationship is one of the main themes of modern parasitology. Recent revolutions in science, including the development of various fluorescent proteins/probes and two-photon microscopy, have made it possible to directly visualize and study the mechanisms underlying the interaction between the host and pathogen. Here, we describe our method of preparing and setting-up the liver for our experimental approach of using intravital imaging to examine the interaction between Plasmodium berghei ANKA and antigen-specific CD8 + T cells during the liver-stage of the infection in four dimensions. Since the liver is positioned near the diaphragm, neutralization of respiratory movements is critical during the imaging process. In addition, blood circulation and temperature can be affected by the surgical exposure due to the anatomy and tissue structure of the liver. To control respiration, we recommend anesthesia with isoflurane inhalation at 1% during the surgery. In addition, our protocol introduces a cushion of gauze around the liver to avoid external pressure on the liver during intravital imaging using an inverted microscope, which makes it possible to image the liver tissue for long periods with minimal reduction in the blood circulation and with minimal displacement and tissue damage. The key point of this method is to reduce respiratory movements and external pressure on the liver tissue during intravital imaging. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Epoxy Resins in Electron Microscopy

PubMed Central

Finck, Henry

1960-01-01

A method of embedding biological specimens in araldite 502 (Ciba) has been developed for materials available in the United States. Araldite-embedded tissues are suitable for electron microscopy, but the cutting qualities of the resin necessitates more than routine attention during microtomy. The rather high viscosity of araldite 502 also seems to be an unnecessary handicap. The less viscous epoxy epon 812 (Shell) produces specimens with improved cutting qualities, and has several features—low shrinkage and absence of specimen damage during cure, minimal compression of sections, relative absence of electron beam-induced section damage, etc.—which recommends it as a routine embedding material. The hardness of the cured resin can be easily adjusted by several methods to suit the materials embedded in it. Several problems and advantages of working with sections of epoxy resins are also discussed. PMID:13822825

Femtosecond laser ablation of the stapes

NASA Astrophysics Data System (ADS)

McCaughey, Ryan G.; Sun, Hui; Rothholtz, Vanessa S.; Juhasz, Tibor; Wong, Brian J. F.

2009-03-01

A femtosecond laser, normally used for LASIK eye surgery, is used to perforate cadaveric human stapes. The thermal side effects of bone ablation are measured with a thermocouple in an inner ear model and are found to be within acceptable limits for inner ear surgery. Stress and acoustic events, recorded with piezoelectric film and a microphone, respectively, are found to be negligible. Optical microscopy, scanning electron microscopy, and optical coherence tomography are used to confirm the precision of the ablation craters and lack of damage to the surrounding tissue. Ablation is compared to that from an Er:YAG laser, the current laser of choice for stapedotomy, and is found to be superior. Ultra-short-pulsed lasers offer a precise and efficient ablation of the stapes, with minimal thermal and negligible mechanical and acoustic damage. They are, therefore, ideal for stapedotomy operations.

Improved sensitivity to fluorescence for cancer detection in wide-field image-guided neurosurgery

PubMed Central

Jermyn, Michael; Gosselin, Yoann; Valdes, Pablo A.; Sibai, Mira; Kolste, Kolbein; Mercier, Jeanne; Angulo, Leticia; Roberts, David W.; Paulsen, Keith D.; Petrecca, Kevin; Daigle, Olivier; Wilson, Brian C.; Leblond, Frederic

2015-01-01

In glioma surgery, Protoporphyrin IX (PpIX) fluorescence may identify residual tumor that could be resected while minimizing damage to normal brain. We demonstrate that improved sensitivity for wide-field spectroscopic fluorescence imaging is achieved with minimal disruption to the neurosurgical workflow using an electron-multiplying charge-coupled device (EMCCD) relative to a state-of-the-art CMOS system. In phantom experiments the EMCCD system can detect at least two orders-of-magnitude lower PpIX. Ex vivo tissue imaging on a rat glioma model demonstrates improved fluorescence contrast compared with neurosurgical fluorescence microscope technology, and the fluorescence detection is confirmed with measurements from a clinically-validated spectroscopic probe. Greater PpIX sensitivity in wide-field fluorescence imaging may improve the residual tumor detection during surgery with consequent impact on survival. PMID:26713218

Fresh osteochondral allografts-procurement and tissue donation in Europe.

PubMed

Schmidt, S; Schulte, A; Schwarz, S; Hofmann, N; Tietz, S; Boergel, M; Sixt, S U

2017-07-01

Fresh osteochondral allografts are a well-established treatment for large, full-thickness cartilage defects. The clinical outcome for carefully selected patients is very favorable, especially for the young and active and graft survival up to 25 years has been described in the literature. Furthermore, a high patient satisfaction rate has been reported, but the biggest obstacle to overcome is the availability of tissue for transplantation. Large fresh bone allografts for cartilage damage repair only can be harvested from organ donors following organ removal or cadaveric donors, preferably in the setting of an operation room to minimize possible contamination of the tissue. Apart from the logistic challenges this entails, an experienced recovery team is needed. Furthermore, the public as well as medical staff is much less aware of the possibility and requirements of tissue donation than organ donation and families of deceased are rarely approached for bone and cartilage donation. This review aims to highlight the current situation of organ and tissue donation in Europe with special focus on the processing of bones and possible safety and quality concerns. We analyze what may prevent consent and what might be done to improve the situation of tissue donation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Control of Mucosal Candidiasis in the Zebrafish Swim Bladder Depends on Neutrophils That Block Filament Invasion and Drive Extracellular-Trap Production

PubMed Central

Gratacap, Remi L.; Scherer, Allison K.; Seman, Brittany G.

2017-01-01

ABSTRACT Candida albicans is a ubiquitous mucosal commensal that is normally prevented from causing acute or chronic invasive disease. Neutrophils contribute to protection in oral infection but exacerbate vulvovaginal candidiasis. To dissect the role of neutrophils during mucosal candidiasis, we took advantage of a new, transparent zebrafish swim bladder infection model. Intravital microscopic tracking of individual animals revealed that the blocking of neutrophil recruitment leads to rapid mortality in this model through faster disease progression. Conversely, artificial recruitment of neutrophils during early infection reduces disease pressure. Noninvasive longitudinal tracking showed that mortality is a consequence of C. albicans breaching the epithelial barrier and invading surrounding tissues. Accordingly, we found that a hyperfilamentous C. albicans strain breaches the epithelial barrier more frequently and causes mortality in immunocompetent zebrafish. A lack of neutrophils at the infection site is associated with less fungus-associated extracellular DNA and less damage to fungal filaments, suggesting that neutrophil extracellular traps help to protect the epithelial barrier from C. albicans breach. We propose a homeostatic model where C. albicans disease pressure is balanced by neutrophil-mediated damage of fungi, maintaining this organism as a commensal while minimizing the risk of damage to host tissue. The unequaled ability to dissect infection dynamics at a high spatiotemporal resolution makes this zebrafish model a unique tool for understanding mucosal host-pathogen interactions. PMID:28607100

Physics and Histologic Evaluation of Rotary, Ultrasonic, and Sonic Instruments.

PubMed

Ruga, Emanuele; Amerio, Ettore; Carbone, Vincenzo; Volante, Marco; Gandolfo, Sergio

2017-10-01

Rotary instruments (RIs) are the most commonly used to perform osteotomies in many fields of medicine. Owing to a new interest in performing a minimally invasive surgery, over last fifteen years new devices have been used in oral surgery such as ultrasonic instruments (UIs) and, lately, sonic instruments (SIs). Nowadays, bone preservation and regeneration are paramount in many clinical situations and, consequently, it is crucial to rely upon instruments, which cause the least tissue damage during the surgery. Concerning SIs, there is still few information about workload to be applied and related temperature increases; furthermore, there are no comparative in-vivo studies, which analyze the thermal and mechanical effects on bone. Thus, SIs have been compared with UIs and RIs in terms of heat generation, operating time, accuracy, and tissue damage. Decalcification and sectioning procedure resulted in no significant differences between the applied instruments in terms of bone damage. RIs resulted more efficient than UIs (P < 0.001), but demonstrated low accuracy (NRS 4.9), whereas SIs (P = 0.005) required more time to perform the osteotomy. The maximum temperature increase occurred in the ultrasonic group. Even though SI were the slowest, they have proved to be the most accurate (NRS 8.4) in comparison with UI (NRS 7.6) and RI (NRS 4.9). Within the limit of this study, sonic instruments could be considered a safe alternative to ultrasonic instruments.

Possible role of Arthrospira platensis in reversing oxidative stress-mediated liver damage in rats exposed to lead.

PubMed

Khalil, Samah R; Elhady, Walaa M; Elewa, Yaser H A; Abd El-Hameed, Noura E; Ali, Sozan A

2018-01-01

Environmental pollutants, particularly metallic elements, mobilized and released into the environment, eventually accumulate in the food chain and thus pose a serious threat to human and animal health. In the present study, the role of Arthrospira (Spirulina platensis; SP) as a protector against oxidative stress-mediated liver damage induced by an exposure to lead acetate (LA; as a metallic pollutant) was assessed. To achieve this aim, rats were orally administered with 300 mg/kg bw SP for 15 days, before and concurrently with an intraperitoneal injection of 50 mg/kg bw LA (6 injections throughout 15 days). As a result, co-administration of SP with LA reduced the amount of lead that accumulated in both blood and liver tissue of the exposed rats and minimized the increased levels of lipid peroxidation, protein oxidation, DNA oxidative damage, and liver enzyme endpoints. In addition, because of SP administration, the levels of depleted biomarkers of antioxidant status and total antioxidant capacity in LA-exposed rats improved. Moreover, SP protected the liver tissue against the changes caused by LA exposure and also decreased the reactivity of HSP70 in the cytoplasm of hepatocytes. Collectively, our data suggest that SP has a potential use as a food supplement in the regions highly polluted with heavy metals such as lead. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Conformal thermal therapy using planar ultrasound transducers and adaptive closed-loop MR temperature control: demonstration in gel phantoms and ex vivo tissues

NASA Astrophysics Data System (ADS)

Tang, K.; Choy, V.; Chopra, R.; Bronskill, M. J.

2007-05-01

MRI-guided transurethral ultrasound therapy offers a minimally invasive approach for the treatment of localized prostate cancer. Integrating a multi-element planar transducer with active MR temperature feedback can enable three-dimensional conformal thermal therapy of a target region within the prostate gland while sparing surrounding normal tissues. Continuous measurement of the temperature distribution in tissue enables dynamic compensation for unknown changes in blood flow and tissue properties during treatment. The main goal of this study was to evaluate the feasibility of using active temperature feedback on a clinical 1.5 T MR imager for conformal thermal therapy. MR thermometry was performed during heating in both gel phantoms and excised tissue with a transurethral heating applicator, and the rotation rate and power were varied based on the thermal measurements. The capability to produce a region of thermal damage that matched a target boundary was evaluated. The influence of a cooling gradient (to simulate cooling of the rectum or urethra) on the desired pattern of thermal damage was also investigated in gel phantoms. Results showed high correlation between the desired target boundary and the 55 °C isotherm generated during heating with an average distance error of 0.9 mm ± 0.4 mm (n = 6) in turkey breasts, 1.4 mm ± 0.6 mm (n = 4) in gel phantoms without rectal cooling and 1.4 mm ± 0.6 mm (n = 3) in gel phantoms with rectal cooling. The results were obtained using a temporal update rate of 5 s, a spatial resolution of 3 × 3 × 10 mm for the control point, and a temperature uncertainty of approximately 1 °C. The performance of the control algorithm under these conditions was comparable to that of simulations conducted previously by our group. Overall, the feasibility of generating targeted regions of thermal damage with a transurethral heating applicator and active MR temperature feedback has been demonstrated experimentally. This method of treatment appears capable of accounting for unpredictable and varying tissue properties during the treatment.

Management of heat in laser tissue welding using NIR cover window material.

PubMed

Sriramoju, Vidyasagar; Savage, Howard; Katz, Alvin; Muthukattil, Ronex; Alfano, Robert R

2011-12-01

Laser tissue welding (LTW) is a novel method of surgical wound closure by the use of laser radiation to induce fusion of the biological tissues. Molecular dynamics associated with LTW is a result of thermal and non-thermal mechanisms. This research focuses exclusively on better heat management to reduce thermal damage of tissues in LTW using a near infrared laser radiation. An infrared continuous-wave (CW) laser radiation at 1,450 nm wavelength corresponding to the absorption band from combination vibrational modes of water is used to weld together ex vivo porcine aorta. In these studies we measured the optimal laser power and scan speed, for better tensile strength of the weld and lesser tissue dehydration. Significant amount of water loss from the welded tissue results in cellular death and tissue buckling. Various thermally conductive optical cover windows were used as heat sinks to reduce thermal effects during LTW for the dissipation of the heat. The optimal use of the method prevents tissue buckling and minimizes the water loss. Diamond, sapphire, BK7, fused silica, and IR quartz transparent optical cover windows were tested. The data from this study suggests that IR-quartz as the material with optimal thermal conductivity is ideal for laser welding of the porcine aorta. Copyright © 2011 Wiley Periodicals, Inc.

Cell sheet-based tissue engineering for fabricating 3-dimensional heart tissues.

PubMed

Shimizu, Tatsuya

2014-01-01

In addition to stem cell biology, tissue engineering is an essential research field for regenerative medicine. In contrast to cell injection, bioengineered tissue transplantation minimizes cell loss and has the potential to repair tissue defects. A popular approach is scaffold-based tissue engineering, which utilizes a biodegradable polymer scaffold for seeding cells; however, new techniques of cell sheet-based tissue engineering have been developed. Cell sheets are harvested from temperature-responsive culture dishes by simply lowering the temperature. Monolayer or stacked cell sheets are transplantable directly onto damaged tissues and cell sheet transplantation has already been clinically applied. Cardiac cell sheet stacking produces pulsatile heart tissue; however, lack of vasculature limits the viable tissue thickness to 3 layers. Multistep transplantation of triple-layer cardiac cell sheets cocultured with endothelial cells has been used to form thick vascularized cardiac tissue in vivo. Furthermore, in vitro functional blood vessel formation within 3-dimensional (3D) tissues has been realized by successfully imitating in vivo conditions. Triple-layer cardiac cell sheets containing endothelial cells were layered on vascular beds and the constructs were media-perfused using novel bioreactor systems. Interestingly, cocultured endothelial cells migrate into the vascular beds and form perfusable blood vessels. An in vitro multistep procedure has also enabled the fabrication of thick, vascularized heart tissues. Cell sheet-based tissue engineering has revealed great potential to fabricate 3D cardiac tissues and should contribute to future treatment of severe heart diseases and human tissue model production.

Design of self-assembling beta-hairpin pepide-based hydrogels for tissue engineering applications

NASA Astrophysics Data System (ADS)

Butterick, Lisa Ann

The field of tissue engineering aims to repair damaged tissues and organs with diminished function. One approach used in tissue engineering is to introduce cells and/or growth factors to the damaged tissue in either one of two ways. The first method is an invasive procedure where cells are introduced to a preformed scaffold and cultured in vitro. The scaffold is then inserted into the host by making an incision at the site of interest, which must be as large as the preformed scaffold. The second method is a minimally invasive procedure where cells are suspended in a polymeric solution and injected via syringe. After leaving the syringe, the material undergoes a phase transition to form a hydrogel at the site of introduction. Regardless of the delivery mechanism employed, development of an appropriate scaffold conducive to cellular proliferation and extracellular matrix production is critical to the success of the implanted material in persuading the body to repair itself. In working toward this goal, we have developed a family of beta-hairpin peptides, based on the design MAX1, that undergoes intramolecular folding and self-assembly to form rigid hydrogels in response to changes in pH, ionic strength, and temperature. From a molecular design standpoint of view, site specific N-methylation of MAX1 was performed to determine the importance of forming hydrogen bonds during the self-assembly event and its effect on hydrogelation. The remainder of this thesis is dedicated to the development of materials and minimally methodologies to deliver gel/cell constructs via syringe to target sites to aid in tissue repair. A peptide, MAX7CNB was designed that undergoes folding and assembly in response to ultraviolet light to form hydrogel material. In addition, MAX8 was rationally designed to display the appropriate hydrogelation kinetics to achieve homogenous cellular encapsulation throughout the gel matrix. MAX8 gel/cell scaffolds can be easily delivered via syringe to secondary target sites while maintaining cellular homogeneity, viability and remain fixed at the site of introduction. Additionally, preliminary in vitro based studies employing mouse peritoneal macrophages suggest the MAX8 gels are non-inflammatory in nature and may not elicit an in vivo immune response upon implantation. It has been demonstrated throughout this thesis that by employing amino acids as fundamental building blocks, peptide sequences can be designed to undergo molecular recognition, resulting in hydrogel material for use in tissue engineering applications.

Changes in optical properties during heating of ex vivo liver tissues

NASA Astrophysics Data System (ADS)

Nagarajan, Vivek Krishna; Gogineni, Venkateshwara R.; White, Sarah B.; Yu, Bing

2017-02-01

Thermal ablation is the use of heat to induce cell death through coagulative necrosis. Ideally, complete ablation of tumor cells with no damage to surrounding critical structures such as blood vessels, nerves or even organs is desired. Ablation monitoring techniques are often employed to ensure optimal tumor ablation. In thermal tissue ablation, tissue damage is known to be dependent on the temperature and time of exposure. Aptly, current methods for monitoring ablation rely profoundly on local tissue temperature and duration of heating to predict the degree of tissue damage. However, such methods do not take into account the microstructural and physiological changes in tissues as a result of thermocoagulation. Light propagation within biological tissues is known to be dependent on the tissue microstructure and physiology. During tissue denaturation, changes in tissue structure alter light propagations in tissue which could be used to directly assess the extent of thermal tissue damage. We report the use of a spectroscopic system for monitoring the tissue optical properties during heating of ex vivo liver tissues. We observed that during tissue denaturation, continuous changes in wavelength-averaged μa(λ) and μ's(λ) followed a sigmoidal trend and are correlated with damage predicted by Arrhenius model.

Quantification of change in vocal fold tissue stiffness relative to depth of artificial damage.

PubMed

Rohlfs, Anna-Katharina; Schmolke, Sebastian; Clauditz, Till; Hess, Markus; Müller, Frank; Püschel, Klaus; Roemer, Frank W; Schumacher, Udo; Goodyer, Eric

2017-10-01

To quantify changes in the biomechanical properties of human excised vocal folds with defined artificial damage. The linear skin rheometer (LSR) was used to obtain a series of rheological measurements of shear modulus from the surface of 30 human cadaver vocal folds. The tissue samples were initially measured in a native condition and then following varying intensities of thermal damage. Histological examination of each vocal fold was used to determine the depth of artificial alteration. The measured changes in stiffness were correlated with the depth of cell damage. For vocal folds in a pre-damage state the shear modulus values ranged from 537 Pa to 1,651 Pa (female) and from 583 Pa to 1,193 Pa (male). With increasing depth of damage from the intermediate layer of the lamina propria (LP), tissue stiffness increased consistently (compared with native values) following application of thermal damage to the vocal folds. The measurement showed an increase of tissue stiffness when the depth of tissue damage was extending from the intermediate LP layer downwards. Changes in the elastic characteristics of human vocal fold tissue following damage at defined depths were demonstrated in an in vitro experiment. In future, reproducible in vivo measurements of elastic vocal fold tissue alterations may enable phonosurgeons to infer the extent of subepithelial damage from changes in surface elasticity.

[Positive effects of physical exercise on reducing the relationship between subcutaneous abdominal fat and morbility risk].

PubMed

González Calvo, G; Hernández Sánchez, S; Pozo Rosado, P; García López, D

2011-01-01

The consequences related to the accumulation of abdominal fat above healthy levels create a considerable organic damage. Among the physiological consequences we can highlight heart diseases, hypertension, type-2 diabetes, obesity and metabolic syndrome, which drastically reduce life expectancy and quality. Evidence shows that health improvement is correlated to greater levels of physical activity. However, physical exercise can create oxidative damage on organs and muscular tissue, more relevant in subjects with a high percentage of abdominal fat. This piece of work determines which are the fundamental variables of the exercise program in order to optimize its advantages while minimizing oxidative stress. To know the key variables in the accumulation of abdominal fat above healthy levels, and the role of exercise in prevention and improvement of such issue. SPECIFIC PURPOSES: 1) to identify the key variables in an exercise program aimed at reducing abdominal fat; 2) to understand the relationship between abdominal fat, health and exercise; 3) to review the latest research related to physical exercise and its effect on abdominal adipose tissue. A search and identification of original and reviewed articles will be carried out in indexed impact journals within the main databases. Regular physical exercise, most notably aerobic one, reduces body adipose tissue deposits in general, and abdominal ones in particular, both in obese and overweight subjects.

Laser radiation bracket debonding

NASA Astrophysics Data System (ADS)

Dostálová, Tat'jana; Jelínková, Helena; Šulc, Jan; Koranda, Petr; Nemec, Michal; Racek, Jaroslav; Miyagi, Mitsunobu

2008-02-01

Ceramic brackets are an aesthetic substitute for conventional stainless steel brackets in orthodontic patients. However, ceramic brackets are more brittle and have higher bond strengths, which can lead to bracket breakage and enamel damage during classical type of debonding. This study examined the possibility of laser radiation ceramic brackets removing as well as the possible damage of a surface structure of hard dental tissue after this procedure. Two types of lasers were used for the experiments - a laser diode LIMO HLU20F400 generating a wavelength of 808 nm with the maximum output power 20W at the end of the fiber (core diameter 400 μm, numerical aperture 0.22). As a second source, a diode-pumped Tm:YAP laser system generating a wavelength of 1.9 μm, with up to 3.8 W maximum output power was chosen. For the investigation, extracted incisors with ceramic brackets were used. In both cases, laser radiation was applied for 0.5 minute at a maximum power of 1 W. Temperature changes of the irradiated tissue was registered by camera Electrophysics PV320. After the interaction experiment, the photo-documentation was prepared by the stereomicroscope Nikon SMZ 2T, Japan. The surface tissue analysis was processed in "low vacuum" (30 Pa) regime without desiccation. This technique was used to record back-scattered electron images. Selecting the appropriate laser, resin, and bracket combination can minimize risks of enamel degradation and make debonding more safe.

Energy-Based Tissue Fusion for Sutureless Closure: Applications, Mechanisms, and Potential for Functional Recovery.

PubMed

Kramer, Eric A; Rentschler, Mark E

2018-06-04

As minimally invasive surgical techniques progress, the demand for efficient, reliable methods for vascular ligation and tissue closure becomes pronounced. The surgical advantages of energy-based vessel sealing exceed those of traditional, compression-based ligatures in procedures sensitive to duration, foreign bodies, and recovery time alike. Although the use of energy-based devices to seal or transect vasculature and connective tissue bundles is widespread, the breadth of heating strategies and energy dosimetry used across devices underscores an uncertainty as to the molecular nature of the sealing mechanism and induced tissue effect. Furthermore, energy-based techniques exhibit promise for the closure and functional repair of soft and connective tissues in the nervous, enteral, and dermal tissue domains. A constitutive theory of molecular bonding forces that arise in response to supraphysiological temperatures is required in order to optimize and progress the use of energy-based tissue fusion. While rapid tissue bonding has been suggested to arise from dehydration, dipole interactions, molecular cross-links, or the coagulation of cellular proteins, long-term functional tissue repair across fusion boundaries requires that the reaction to thermal damage be tailored to catalyze the onset of biological healing and remodeling. In this review, we compile and contrast findings from published thermal fusion research in an effort to encourage a molecular approach to characterization of the prevalent and promising energy-based tissue bond.

Use of Lasers in Laryngeal Surgery

PubMed Central

Yan, Yan; Olszewski, Aleksandra E.; Hoffman, Matthew R.; Zhuang, Peiyun; Ford, Charles N.; Dailey, Seth H.; Jiang, Jack J.

2012-01-01

Lasers are a relatively recent addition to laryngeal surgery. Since their invention, laser use and applications have expanded rapidly. In this paper, we discuss the benefits and disadvantages of lasers for different procedures, as well as ways to overcome commonly faced clinical problems. The use of lasers in surgery has offered a time- and cost-efficient alternative to cold surgical techniques, and has been employed in the treatment of numerous laryngeal pathologies, including stenoses, recurrent respiratory papillomatosis, leukoplakia, nodules, malignant laryngeal disease, and polypoid degeneration (Reinke’s edema). However, lasers can incur adjacent tissue damage and vocal fold scarring. These problems can be minimized through understanding the mechanisms by which lasers function and correctly manipulating the parameters under a surgeon’s control. By varying fluence, power density, and pulsation, tissue damage can be decreased and lasers can be used with greater confidence. The various types of lasers and their applications to the treatment of specific pathologies are reviewed with the intention of helping surgeons select the best tool for a given procedure. Recent applications of lasers to treat benign laryngeal lesions and severe laryngomalacia demonstrate that additional research must be conducted in order to realize the full potential of this surgical tool. PMID:19487102

Blood-brain barrier disruption induced by diagnostic ultrasound combined with microbubbles in mice.

PubMed

Zhao, Bingxia; Chen, Yihan; Liu, Jinfeng; Zhang, Li; Wang, Jing; Yang, Yali; Lv, Qing; Xie, Mingxing

2018-01-12

To investigate the effects of the microbubble (MB) dose, mechanism index (MI) and sonication duration on blood-brain barrier (BBB) disruption induced by diagnostic ultrasound combined with MBs as well as to investigate the potential molecular mechanism. The extent of BBB disruption increased with MB dose, MI and sonication duration. A relatively larger extent of BBB disruption associated with minimal tissue damage was achieved by an appropriate MB dose and ultrasound exposure parameters with diagnostic ultrasound. Decreased expression of ZO-1, occludin and claudin-5 were correlated with disruption of the BBB, as confirmed by paracellular passage of the tracer lanthanum nitrate into the brain parenchyma after BBB disruption. These findings indicated that this technique is a promising tool for promoting brain delivery of diagnostic and therapeutic agents in the diagnosis and treatment of brain diseases. The extent of BBB disruption was qualitatively assessed by Evans blue (EB) staining and quantitatively analyzed by an EB extravasation measurement. A histological examination was performed to evaluate tissue damage. Expression of tight junction (TJ) related proteins ZO-1, occludin and claudin-5 was determined by western blotting analysis and immunohistofluorescence. Transmission electron microscopy was performed to observe ultrastructure changes of TJs after BBB disruption.

Use of radiation protraction to escalate biologically effective dose to the treatment target

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuperman, V. Y.; Spradlin, G. S.; Department of Mathematics, Embry-Riddle University, Daytona Beach, Florida 32114

2011-12-15

Purpose: The aim of this study is to evaluate how simultaneously increasing fraction time and dose per fraction affect biologically effective dose for the target (BED{sub tar}) while biologically effective dose for the normal tissue (BED{sub nt}) is fixed. Methods: In this investigation, BED{sub tar} and BED{sub nt} were studied by assuming mono-exponential repair of sublethal damage with tissue dependent repair half-time. Results: Our results demonstrate that under certain conditions simultaneously increasing fraction time and dose per fraction result in increased BED{sub tar} while BED{sub nt} is fixed. The dependence of biologically effective dose on fraction time is influenced bymore » the dose rate. In this investigation we analytically determined time-varying dose rate R-tilde which minimizes BED. Changes in BED with fraction time were compared for constant dose rate and for R-tilde. Conclusions: A number of recent experimental and theoretical studies have demonstrated that slow delivery of radiation (known as radiation protraction) leads to reduced therapeutic effect because of increased repair of sublethal damage. In contrast, our analysis shows that under certain conditions simultaneously increasing fraction time and dose per fraction are radiobiologically advantageous.« less

An unusual etiology in cold injury: Liquefied petroleum gas.

PubMed

Kapı, Emin; Bozkurt, Mehmet; Taylan Filinte, Gaye; Kuvat, Samet Vasfi; Alioğlu, Celal

2017-05-01

Cold injury is a condition that causes reversible and irreversible damage when tissues are exposed to cold. This injury occurs due to various etiologies, and the most commonly observed ones include contact with liquefied petroleum gas (LPG) used in households, vehicles, and industry. LPG is a type of gas stored in liquid state under high pressure within cylinders. LPG contains a mixture of propane and butane gases. Direct contact of these gases with the tissues has the potential to cause metabolic, toxic, and respiratory damage. In this study, we present the cases of four patients with cold injury in the face and upper extremity caused by a pressurized jet stream of liquid gas that escaped out of the valves of the LPG cylinders. The patients had bullous lesions in the upper extremities and the face and second- and third-degree cold injuries with fibrotic and necrotic areas. The superficial defects secondarily healed with minimal scarring, while the necrotic finger had to be amputated. Cold injury on the skin caused by high-pressure jet streams of liquid gas as in our study is a rare occurrence. Our patients are important cases due to the rare etiology of cold injury.

High strain-rate soft material characterization via inertial cavitation

NASA Astrophysics Data System (ADS)

Estrada, Jonathan B.; Barajas, Carlos; Henann, David L.; Johnsen, Eric; Franck, Christian

2018-03-01

Mechanical characterization of soft materials at high strain-rates is challenging due to their high compliance, slow wave speeds, and non-linear viscoelasticity. Yet, knowledge of their material behavior is paramount across a spectrum of biological and engineering applications from minimizing tissue damage in ultrasound and laser surgeries to diagnosing and mitigating impact injuries. To address this significant experimental hurdle and the need to accurately measure the viscoelastic properties of soft materials at high strain-rates (103-108 s-1), we present a minimally invasive, local 3D microrheology technique based on inertial microcavitation. By combining high-speed time-lapse imaging with an appropriate theoretical cavitation framework, we demonstrate that this technique has the capability to accurately determine the general viscoelastic material properties of soft matter as compliant as a few kilopascals. Similar to commercial characterization algorithms, we provide the user with significant flexibility in evaluating several constitutive laws to determine the most appropriate physical model for the material under investigation. Given its straightforward implementation into most current microscopy setups, we anticipate that this technique can be easily adopted by anyone interested in characterizing soft material properties at high loading rates including hydrogels, tissues and various polymeric specimens.

Piezosurgery as a further technical adjunct in minimally invasive supraorbital keyhole approach and lateral orbitotomy.

PubMed

Iacoangeli, Maurizio; Di Rienzo, Alessandro; Nocchi, Niccolo; Balercia, Paolo; Lupi, Ettore; Regnicolo, Luana; Di Somma, Lucia Giovanna Maria; Alvaro, Lorenzo; Scerrati, Massimo

2015-03-01

One of the problems in neurosurgery is how to perform rapid and effective craniotomies that minimize the risk of injury to underlying eloquent structures. The traditional high-powered pneumatic tools and saws are efficient in terms of speed and penetration, but they can provoke bone necrosis and sometimes damage neurovascular structures. As an alternative, we evaluated the piezoelectric bone scalpel (piezosurgery), a device that potentially allows thinner and more precise bone cutting without lesioning neighboring delicate structures, even in the case of accidental contact. From January 2009 to December 2011, 20 patients (8 men and 12 women), 19 to 72 years of age (mean: 49.3 years) were treated using piezosurgery. Surgery was performed for the removal of anterior cranial fossa meningiomas, orbital tumors, and sinonasal lesions with intracranial extension. The time required to perform craniotomy using piezosurgery is a few minutes longer than with traditional drills. No damage was observed using the piezoelectric device. Follow-up clinical and neuroradiologic evaluation showed a faster and better ossification of the bone flap with good esthetic results. Piezosurgery is a new promising technique for selective bone cutting with soft tissue preservation. This instrument seems suitable to perform precise thin osteotomies while limiting damage to the bone itself and to the underlying delicate structures even in the case of unintentional contact. These advantages make the piezoelectric bone scalpel a particularly attractive instrument in neurosurgery. Georg Thieme Verlag KG Stuttgart · New York.

Cranial nerve threshold for thermal injury induced by MRI-guided high-intensity focused ultrasound (MRgHIFU): preliminary results on an optic nerve model.

PubMed

Harnof, Sagi; Zibly, Zion; Cohen, Zvi; Shaw, Andrew; Schlaff, Cody; Kassel, Neal F

2013-04-01

Future clinical applications of magnetic resonance imaging-guided high-intensity focused ultrasound (MRgHIFU) are moving toward the management of different intracranial pathologies. We sought to validate the production, safety, and efficacy of thermal injury to cranial nerves generated by MRgHIFU. In this study, five female domestic pigs underwent a standard bifrontal craniectomy under general anesthesia. Treatment was then given using an MRgHIFU system to induce hyperthermic ablative sonication (6 to 10 s; 50 to 2000 J.) Histological analyses were done to confirm nerve damage; temperature measured on the optic nerve was approximately 53.4°C (range: 39°C to 70°C.) Histology demonstrated a clear definition between a necrotic, transitional zone, and normal tissue. MRgHIFU induces targeted thermal injury to nervous tissue within a specific threshold of 50°C to 60°C with the tissue near the sonication center yielding the greatest effect; adjacent tissue showed minimal changes. Additional studies utilizing this technology are required to further establish accurate threshold parameters for optic nerve thermo-ablation.

Thermal model for optimization of vascular laser tissue soldering.

PubMed

Bogni, Serge; Stumpp, Oliver; Reinert, Michael; Frenz, Martin

2010-06-01

Laser tissue soldering (LTS) is a promising technique for tissue fusion based on a heat-denaturation process of proteins. Thermal damage of the fused tissue during the laser procedure has always been an important and challenging problem. Particularly in LTS of arterial blood vessels strong heating of the endothelium should be avoided to minimize the risk of thrombosis. A precise knowledge of the temperature distribution within the vessel wall during laser irradiation is inevitable. The authors developed a finite element model (FEM) to simulate the temperature distribution within blood vessels during LTS. Temperature measurements were used to verify and calibrate the model. Different parameters such as laser power, solder absorption coefficient, thickness of the solder layer, cooling of the vessel and continuous vs. pulsed energy deposition were tested to elucidate their impact on the temperature distribution within the soldering joint in order to reduce the amount of further animal experiments. A pulsed irradiation with high laser power and high absorbing solder yields the best results. (c) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A biomechanical evaluation to optimize the configuration of a hinged external fixator for the primary treatment of severely displaced intraarticular calcaneus fractures with soft tissue damage.

PubMed

Besch, Lutz; Schmidt, Ina; Mueller, Michael; Daniels-Wredenhagen, Mark; Hilgert, Ralf-Eric; Varoga, Deike; Seekamp, Andreas

2008-01-01

The purpose of this investigation was to develop an optimized hinged external fixator for the primary treatment of dislocated, intra-articular calcaneus fractures with associated soft tissue damage. To this end, a calcaneus model was made out of a polyurethane block, and a steel cylinder served as the ankle joint and was connected to a synthetic model of the tibia via a metal clamp. A saw cut served as the fracture in the model. A Steinmann nail and Schanz screw were placed in defined positions in the model and connected medially and laterally with longitudinal support rods. The fixator allowed a total of 20 degrees of plantar- and dorsiflexion, with rotation in the virtual axis of the upper ankle joint. Changes in the model fracture were measured during cyclical strain, and at different screw positions in the model tibia and calcaneus. Miniature force sensors located on the longitudinal support rods, and a plantar tension spring, were used to measure pressure and tension. Reproducible values were determined and, with the optimal configuration, shifting within the osteotomy was minimal. In the experimental configuration, optimal tibial screw placement was 70 mm proximal to the rotation axis of the upper ankle joint, and optimal placement of the Steinmann nail was in the posterior surface of the calcaneus. These findings indicated that the hinged fixator allows 20 degrees of ankle movement without alteration of the rotation axis, and suggest that this type of external fixator can be used in all types of calcaneal fracture regardless of the soft tissue damage. ACFAS Level of Clinical Evidence: 5c.

Electron Nuclear Dynamics Simulations of Proton Cancer Therapy Reactions: Water Radiolysis and Proton- and Electron-Induced DNA Damage in Computational Prototypes.

PubMed

Teixeira, Erico S; Uppulury, Karthik; Privett, Austin J; Stopera, Christopher; McLaurin, Patrick M; Morales, Jorge A

2018-05-06

Proton cancer therapy (PCT) utilizes high-energy proton projectiles to obliterate cancerous tumors with low damage to healthy tissues and without the side effects of X-ray therapy. The healing action of the protons results from their damage on cancerous cell DNA. Despite established clinical use, the chemical mechanisms of PCT reactions at the molecular level remain elusive. This situation prevents a rational design of PCT that can maximize its therapeutic power and minimize its side effects. The incomplete characterization of PCT reactions is partially due to the health risks associated with experimental/clinical techniques applied to human subjects. To overcome this situation, we are conducting time-dependent and non-adiabatic computer simulations of PCT reactions with the electron nuclear dynamics (END) method. Herein, we present a review of our previous and new END research on three fundamental types of PCT reactions: water radiolysis reactions, proton-induced DNA damage and electron-induced DNA damage. These studies are performed on the computational prototypes: proton + H₂O clusters, proton + DNA/RNA bases and + cytosine nucleotide, and electron + cytosine nucleotide + H₂O. These simulations provide chemical mechanisms and dynamical properties of the selected PCT reactions in comparison with available experimental and alternative computational results.

Thermal damage produced by high-irradiance continuous wave CO2 laser cutting of tissue.

PubMed

Schomacker, K T; Walsh, J T; Flotte, T J; Deutsch, T F

1990-01-01

Thermal damage produced by continuous wave (cw) CO2 laser ablation of tissue in vitro was measured for irradiances ranging from 360 W/cm2 to 740 kW/cm2 in order to investigate the extent to which ablative cooling can limit tissue damage. Damage zones thinner than 100 microns were readily produced using single pulses to cut guinea pig skin as well as bovine cornea, aorta, and myocardium. Multiple pulses can lead to increased damage. However, a systematic decrease in damage with irradiance, predicted theoretically by an evaporation model of ablation, was not observed. The damage-zone thickness was approximately constant around the periphery of the cut, consistent with the existence of a liquid layer which stores heat and leads to tissue damage, and with a model of damage and ablation recently proposed by Zweig et al.

Ptychographic X-ray nanotomography quantifies mineral distributions in human dentine

NASA Astrophysics Data System (ADS)

Zanette, I.; Enders, B.; Dierolf, M.; Thibault, P.; Gradl, R.; Diaz, A.; Guizar-Sicairos, M.; Menzel, A.; Pfeiffer, F.; Zaslansky, P.

2015-03-01

Bones are bio-composites with biologically tunable mechanical properties, where a polymer matrix of nanofibrillar collagen is reinforced by apatite mineral crystals. Some bones, such as antler, form and change rapidly, while other bone tissues, such as human tooth dentine, develop slowly and maintain constant composition and architecture for entire lifetimes. When studying apatite mineral microarchitecture, mineral distributions or mineralization activity of bone-forming cells, representative samples of tissue are best studied at submicrometre resolution while minimizing sample-preparation damage. Here, we demonstrate the power of ptychographic X-ray tomography to map variations in the mineral content distribution in three dimensions and at the nanometre scale. Using this non-destructive method, we observe nanostructures surrounding hollow tracts that exist in human dentine forming dentinal tubules. We reveal unprecedented quantitative details of the ultrastructure clearly revealing the spatially varying mineralization density. Such information is essential for understanding a variety of natural and therapeutic effects for example in bone tissue healing and ageing.

Hydrogel based approaches for cardiac tissue engineering.

PubMed

Saludas, Laura; Pascual-Gil, Simon; Prósper, Felipe; Garbayo, Elisa; Blanco-Prieto, María

2017-05-25

Heart failure still represents the leading cause of death worldwide. Novel strategies using stem cells and growth factors have been investigated for effective cardiac tissue regeneration and heart function recovery. However, some major challenges limit their translation to the clinic. Recently, biomaterials have emerged as a promising approach to improve delivery and viability of therapeutic cells and proteins for the regeneration of the damaged heart. In particular, hydrogels are considered one of the most promising vehicles. They can be administered through minimally invasive techniques while maintaining all the desirable characteristics of drug delivery systems. This review discusses recent advances made in the field of hydrogels for cardiac tissue regeneration in detail, focusing on the type of hydrogel (conventional, injectable, smart or nano- and micro-gel), the biomaterials used for its manufacture (natural, synthetic or hybrid) and the therapeutic agent encapsulated (stem cells or proteins). We expect that these novel hydrogel-based approaches will open up new possibilities in drug delivery and cell therapies. Copyright © 2016 Elsevier B.V. All rights reserved.

Using single nuclei for RNA-seq to capture the transcriptome of postmortem neurons

PubMed Central

Krishnaswami, Suguna Rani; Grindberg, Rashel V; Novotny, Mark; Venepally, Pratap; Lacar, Benjamin; Bhutani, Kunal; Linker, Sara B; Pham, Son; Erwin, Jennifer A; Miller, Jeremy A; Hodge, Rebecca; McCarthy, James K; Kelder, Martin; McCorrison, Jamison; Aevermann, Brian D; Fuertes, Francisco Diez; Scheuermann, Richard H; Lee, Jun; Lein, Ed S; Schork, Nicholas; McConnell, Michael J; Gage, Fred H; Lasken, Roger S

2016-01-01

A protocol is described for sequencing the transcriptome of a cell nucleus. Nuclei are isolated from specimens and sorted by FACS, cDNA libraries are constructed and RNA-seq is performed, followed by data analysis. Some steps follow published methods (Smart-seq2 for cDNA synthesis and Nextera XT barcoded library preparation) and are not described in detail here. Previous single-cell approaches for RNA-seq from tissues include cell dissociation using protease treatment at 30 °C, which is known to alter the transcriptome. We isolate nuclei at 4 °C from tissue homogenates, which cause minimal damage. Nuclear transcriptomes can be obtained from postmortem human brain tissue stored at −80 °C, making brain archives accessible for RNA-seq from individual neurons. The method also allows investigation of biological features unique to nuclei, such as enrichment of certain transcripts and precursors of some noncoding RNAs. By following this procedure, it takes about 4 d to construct cDNA libraries that are ready for sequencing. PMID:26890679

Autotransplantation donor tooth site harvesting using piezosurgery

PubMed Central

Ylikontiola, Leena P.; Sándor, George K.

2016-01-01

Background: The harvesting of a tooth as a candidate for tooth autotransplantation requires that the delicate dental tissues around the tooth be minimally traumatized. This is especially so for the periradicular tissues of the tooth root and the follicular tissues surrounding the crown. The aim of this report is to describe the use of piezosurgery as an attempt at morbidity reduction in the harvesting of teeth for autotransplantation. Methods: A piezosurgical handpiece and its selection of tips were easily adapted to allow the harvesting and delivery of teeth for autotransplantation purposes. Results: Twenty premolar teeth were harvested using a piezosurgical device. The harvested teeth were subsequently successfully autotransplanted. All twenty teeth healed in a satisfactory manner without excessive mobility or ankyloses. Conclusions: Piezosurgery avoids some of the traumatic aspects of harvesting teeth and removing bone which are associated with thermal damage from the use of conventional rotary instruments or saws. Piezosurgery can be adapted to facilitate the predictable harvesting of teeth for autotransplantation purposes. PMID:27563612

Localized cortical chronic traumatic encephalopathy pathology after single, severe axonal injury in human brain.

PubMed

Shively, Sharon B; Edgerton, Sarah L; Iacono, Diego; Purohit, Dushyant P; Qu, Bao-Xi; Haroutunian, Vahram; Davis, Kenneth L; Diaz-Arrastia, Ramon; Perl, Daniel P

2017-03-01

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease associated with repetitive mild impact traumatic brain injury from contact sports. Recently, a consensus panel defined the pathognomonic lesion for CTE as accumulations of abnormally hyperphosphorylated tau (p-tau) in neurons (neurofibrillary tangles), astrocytes and cell processes distributed around small blood vessels at sulcal depths in irregular patterns within the cortex. The pathophysiological mechanism for this lesion is unknown. Moreover, a subset of CTE cases harbors cortical β-amyloid plaques. In this study, we analyzed postmortem brain tissues from five institutionalized patients with schizophrenia and history of surgical leucotomy with subsequent survival of at least another 40 years. Because leucotomy involves severing axons bilaterally in prefrontal cortex, this surgical procedure represents a human model of single traumatic brain injury with severe axonal damage and no external impact. We examined cortical tissues at the leucotomy site and at both prefrontal cortex rostral and frontal cortex caudal to the leucotomy site. For comparison, we analyzed brain tissues at equivalent neuroanatomical sites from non-leucotomized patients with schizophrenia, matched in age and gender. All five leucotomy cases revealed severe white matter damage with dense astrogliosis at the axotomy site and also neurofibrillary tangles and p-tau immunoreactive neurites in the overlying gray matter. Four cases displayed p-tau immunoreactivity in neurons, astrocytes and cell processes encompassing blood vessels at cortical sulcal depths in irregular patterns, similar to CTE. The three cases with apolipoprotein E ε4 haplotype showed scattered β-amyloid plaques in the overlying gray matter, but not the two cases with apolipoprotein E ε3/3 genotype. Brain tissue samples from prefrontal cortex rostral and frontal cortex caudal to the leucotomy site, and all cortical samples from the non-leucotomized patients, showed minimal p-tau and β-amyloid pathology. These findings suggest that chronic axonal damage contributes to the unique pathology of CTE over time.

Remote acoustic sensing as a safety mechanism during exposure of metal implants to alternating magnetic fields

PubMed Central

Chatzinoff, Yonatan; Szczepanski, Debby; Bing, Chenchen; Shaikh, Sumbul; Wyman, Omar; Perry, Cameron E.; Richardson, James A.; Burns, Dennis K.; Evers, Bret M.; Greenberg, David E.; Chopra, Rajiv

2018-01-01

Treatment of prosthetic joint infections often involves multiple surgeries and prolonged antibiotic administration, resulting in a significant burden to patients and the healthcare system. We are exploring a non-invasive method to eradicate biofilm on metal implants utilizing high-frequency alternating magnetic fields (AMF) which can achieve surface induction heating. Although proof-of-concept studies demonstrate the ability of AMF to eradicate biofilm in vitro, there is a legitimate safety concern related to the potential for thermal damage to surrounding tissues when considering heating implanted metal objects. The goal of this study was to explore the feasibility of detecting acoustic emissions associated with boiling at the interface between a metal implant and surrounding soft tissue as a wireless safety sensing mechanism. Acoustic emissions generated during in vitro and in vivo AMF exposures were captured with a hydrophone, and the relationship with surface temperature analyzed. The effect of AMF exposure power, surrounding media composition, implant location within the AMF transmitter, and implant geometry on acoustic detection during AMF therapy was also evaluated. Acoustic emissions were reliably identified in both tissue-mimicking phantom and mouse studies, and their onset coincided with the implant temperature reaching the boiling threshold. The viscosity of the surrounding medium did not impact the production of acoustic emissions; however, emissions were not present when the medium was oil due to the higher boiling point. Results of simulations and in vivo studies suggest that short-duration, high-power AMF exposures combined with acoustic sensing can be used to minimize the amount of thermal damage in surrounding tissues. These studies support the hypothesis that detection of boiling associated acoustic emissions at a metal/tissue interface could serve as a real-time, wireless safety indicator during AMF treatment of biofilm on metallic implants. PMID:29746579

Remote acoustic sensing as a safety mechanism during exposure of metal implants to alternating magnetic fields.

PubMed

Cheng, Bingbing; Chatzinoff, Yonatan; Szczepanski, Debby; Bing, Chenchen; Shaikh, Sumbul; Wyman, Omar; Perry, Cameron E; Richardson, James A; Burns, Dennis K; Evers, Bret M; Greenberg, David E; Chopra, Rajiv

2018-01-01

Treatment of prosthetic joint infections often involves multiple surgeries and prolonged antibiotic administration, resulting in a significant burden to patients and the healthcare system. We are exploring a non-invasive method to eradicate biofilm on metal implants utilizing high-frequency alternating magnetic fields (AMF) which can achieve surface induction heating. Although proof-of-concept studies demonstrate the ability of AMF to eradicate biofilm in vitro, there is a legitimate safety concern related to the potential for thermal damage to surrounding tissues when considering heating implanted metal objects. The goal of this study was to explore the feasibility of detecting acoustic emissions associated with boiling at the interface between a metal implant and surrounding soft tissue as a wireless safety sensing mechanism. Acoustic emissions generated during in vitro and in vivo AMF exposures were captured with a hydrophone, and the relationship with surface temperature analyzed. The effect of AMF exposure power, surrounding media composition, implant location within the AMF transmitter, and implant geometry on acoustic detection during AMF therapy was also evaluated. Acoustic emissions were reliably identified in both tissue-mimicking phantom and mouse studies, and their onset coincided with the implant temperature reaching the boiling threshold. The viscosity of the surrounding medium did not impact the production of acoustic emissions; however, emissions were not present when the medium was oil due to the higher boiling point. Results of simulations and in vivo studies suggest that short-duration, high-power AMF exposures combined with acoustic sensing can be used to minimize the amount of thermal damage in surrounding tissues. These studies support the hypothesis that detection of boiling associated acoustic emissions at a metal/tissue interface could serve as a real-time, wireless safety indicator during AMF treatment of biofilm on metallic implants.

Effects of hydroalcoholic extract of Coriandrum sativum on oxidative damage in pentylenetetrazole-induced seizures in rats

PubMed Central

Karami, Reza; Hosseini, Mahmoud; Mohammadpour, Toktam; Ghorbani, Ahmad; Sadeghnia, Hamid Reza; Rakhshandeh, Hassan; Vafaee, Farzaneh; Esmaeilizadeh, Mahdi

2015-01-01

Background: An important role for oxidative stress, as a consequence of epileptic seizures, has been suggested. Coriandrum sativum has been shown that have antioxidant effects. Central nervous system depressant effects of C. sativum have also been reported. In this study, the effects of hydroalcoholic extract of aerial parts of the plants on brain tissues oxidative damages following seizures induced by pentylenetetrazole (PTZ) was investigated in rats. Methods: The rats were divided into five groups and treated: (1) Control (saline), (2) PTZ (90 mg/kg, i.p.), (3-5) three doses (100, 500 and 1000 mg/kg of C. sativum extract (CSE) before PTZ. Latencies to the first minimal clonic seizures (MCS) and the first generalized tonic-clonic seizures (GTCS) were recorded. The cortical and hippocampal tissues were then removed for biochemical measurements. Results: The extract significantly increased the MCS and GTCS latencies (P < 0.01, P < 0.001) following PTZ-induced seizures. The malondialdehyde (MDA) levels in both cortical and hippocampal tissues of PTZ group were significantly higher than those of the control animals (P < 0.001). Pretreatment with the extract prevented elevation of the MDA levels (P < 0.010–P < 0.001). Following PTZ administration, a significant reduction in total thiol groups was observed in both cortical and hippocampal tissues (P < 0.050). Pre-treatment with the 500 mg/kg of the extract caused a significant prevention of decreased in total thiol concentration in the cortical tissues (P < 0.010). Conclusion: The present study showed that the hydroalcoholic extract of the aerial parts of C. sativum possess significant antioxidant and anticonvulsant activities. PMID:26056549

A Fluorescence-Guided Laser Ablation System for Removal of Residual Cancer in a Mouse Model of Soft Tissue Sarcoma.

PubMed

Lazarides, Alexander L; Whitley, Melodi J; Strasfeld, David B; Cardona, Diana M; Ferrer, Jorge M; Mueller, Jenna L; Fu, Henry L; Bartholf DeWitt, Suzanne; Brigman, Brian E; Ramanujam, Nimmi; Kirsch, David G; Eward, William C

2016-01-01

The treatment of soft tissue sarcoma (STS) generally involves tumor excision with a wide margin. Although advances in fluorescence imaging make real-time detection of cancer possible, removal is limited by the precision of the human eye and hand. Here, we describe a novel pulsed Nd:YAG laser ablation system that, when used in conjunction with a previously described molecular imaging system, can identify and ablate cancer in vivo. Mice with primary STS were injected with the protease-activatable probe LUM015 to label tumors. Resected tissues from the mice were then imaged and treated with the laser using the paired fluorescence-imaging/ laser ablation device, generating ablation clefts with sub-millimeter precision and minimal underlying tissue damage. Laser ablation was guided by fluorescence to target tumor tissues, avoiding normal structures. The selective ablation of tumor implants in vivo improved recurrence-free survival after tumor resection in a cohort of 14 mice compared to 12 mice that received no ablative therapy. This prototype system has the potential to be modified so that it can be used during surgery to improve recurrence-free survival in patients with cancer.

Physical aspects of thermotherapy: A study of heat transport with a view to treatment optimisation

NASA Astrophysics Data System (ADS)

Olsrud, Johan Karl Otto

1998-12-01

Local treatment with the aim to destruct tissue by heating (thermotherapy) may in some cases be an alternative or complement to surgical methods, and has gained increased interest during the last decade. The major advantage of these, often minimally-invasive methods, is that the disease can be controlled with reduced treatment trauma and complications. The extent of thermal damage is a complex function of the physical properties of tissue, which influence the temperature distribution, and of the biological response to heat. In this thesis, methods of obtaining a well-controlled treatment have been studied from a physical point of view, with emphasis on interstitial laser-induced heating of tumours in the liver and intracavitary heating as a treatment for menorrhagia. Hepatic inflow occlusion, in combination with temperature-feedback control of the output power of the laser, resulted in well defined damaged volumes during interstitial laser thermotherapy in normal porcine liver. In addition, phantom experiments showed that the use of multiple diffusing laser fibres allows heating of clinically relevant tissue volumes in a single session. Methods for numerical simulation of heat transport were used to calculate the temperature distribution and the results agreed well with experiments. It was also found from numerical simulation that the influence of light transport on the damaged volume may be negligible in interstitial laser thermotherapy in human liver. Finite element analysis, disregarding light transport, was therefore proposed as a suitable method for 3D treatment planning. Finite element simulation was also used to model intracavitary heating of the uterus, with the purpose of providing an increased understanding of the influence of various treatment parameters on blood flow and on the depth of tissue damage. The thermal conductivity of human uterine tissue, which was used in these simulations, was measured. Furthermore, magnetic resonance imaging (MRI) was investigated as a method of non-invasive temperature monitoring, and an optically tissue-like phantom material, suitable for MRI, was developed. MRI thermometry in this material was shown to be an excellent method for characterization of laser applicators and for verification of numerical calculations. Finally, a water-cooled laser applicator for the treatment of benign prostatic hyperplasia, allowing anatomically correct heating, was developed and evaluated ex-vivo. An increased understanding of the physical aspects of thermotherapy, aided by the methods and results presented in this thesis, constitutes a significant contribution to the performance of safe and efficacious treatment.

The effects of combined selenium nanoparticles and radiation therapy on breast cancer cells in vitro.

PubMed

Chen, Feng; Zhang, Xiao Hong; Hu, Xiao Dan; Liu, Pei Dang; Zhang, Hai Qian

2018-08-01

Radiosensitizers that increase cancer cell radio-sensitivity can enhance the effectiveness of irradiation and minimize collateral damage. Nanomaterial has been employed in conjunction with radiotherapy as radiosensitizers, due to its unique physicochemical properties. In this article, we evaluated selenium nanoparticles (Nano-Se) as a new radiosensitizer. Nano-Se was used in conjunction with irradiation on MCF-7 breast cancer cells, and efficacy and mechanisms of this combined treatment approach were evaluated. Nano-Se reinforced the toxic effects of irradiation, leading to a higher mortality rate than either treatment used alone, inducing cell cycle arrest at the G2/M phase and the activation of autophagy, and increasing both endogenous and irradiation-induced reactive oxygen species formation. These results suggest that Nano-Se can be used as an adjuvant drug to improve cancer cell sensitivity to the toxic effects of irradiation and thereby reduce damage to normal tissue nearby.

Translational findings from cardiovascular stem cell research.

PubMed

Mazhari, Ramesh; Hare, Joshua M

2012-01-01

The possibility of using stem cells to regenerate damaged myocardium has been actively investigated since the late 1990s. Consistent with the traditional view that the heart is a "postmitotic" organ that possesses minimal capacity for self-repair, much of the preclinical and clinical work has focused exclusively on introducing stem cells into the heart, with the hope of differentiation of these cells into functioning cardiomyocytes. This approach is ongoing and retains promise but to date has yielded inconsistent successes. More recently, it has become widely appreciated that the heart possesses endogenous repair mechanisms that, if adequately stimulated, might regenerate damaged cardiac tissue from in situ cardiac stem cells. Accordingly, much recent work has focused on engaging and enhancing endogenous cardiac repair mechanisms. This article reviews the literature on stem cell-based myocardial regeneration, placing emphasis on the mutually enriching interaction between basic and clinical research. Copyright © 2012 Elsevier Inc. All rights reserved.

PHOTODYNAMIC THERAPY OF CANCER: AN UPDATE

PubMed Central

Agostinis, Patrizia; Berg, Kristian; Cengel, Keith A.; Foster, Thomas H.; Girotti, Albert W.; Gollnick, Sandra O.; Hahn, Stephen M.; Hamblin, Michael R.; Juzeniene, Asta; Kessel, David; Korbelik, Mladen; Moan, Johan; Mroz, Pawel; Nowis, Dominika; Piette, Jacques; Wilson, Brian C.; Golab, Jakub

2011-01-01

Photodynamic therapy (PDT) is a clinically approved, minimally invasive therapeutic procedure that can exert a selective cytotoxic activity toward malignant cells. The procedure involves administration of a photosensitizing agent followed by irradiation at a wavelength corresponding to an absorbance band of the sensitizer. In the presence of oxygen, a series of events lead to direct tumor cell death, damage to the microvasculature and induction of a local inflammatory reaction. Clinical studies revealed that PDT can be curative particularly in early-stage tumors. It can prolong survival in inoperable cancers and significantly improve quality of life. Minimal normal tissue toxicity, negligible systemic effects, greatly reduced long-term morbidity, lack of intrinsic or acquired resistance mechanisms, and excellent cosmetic as well as organ function-sparing effects of this treatment make it a valuable therapeutic option for combination treatments. With a number of recent technological improvements, PDT has the potential to become integrated into the mainstream of cancer treatment. PMID:21617154

Scalloped and Yorkie are required for cell cycle re-entry of quiescent cells after tissue damage.

PubMed

Meserve, Joy H; Duronio, Robert J

2015-08-15

Regeneration of damaged tissues typically requires a population of active stem cells. How damaged tissue is regenerated in quiescent tissues lacking a stem cell population is less well understood. We used a genetic screen in the developing Drosophila melanogaster eye to investigate the mechanisms that trigger quiescent cells to re-enter the cell cycle and proliferate in response to tissue damage. We discovered that Hippo signaling regulates compensatory proliferation after extensive cell death in the developing eye. Scalloped and Yorkie, transcriptional effectors of the Hippo pathway, drive Cyclin E expression to induce cell cycle re-entry in cells that normally remain quiescent in the absence of damage. Ajuba, an upstream regulator of Hippo signaling that functions as a sensor of epithelial integrity, is also required for cell cycle re-entry. Thus, in addition to its well-established role in modulating proliferation during periods of tissue growth, Hippo signaling maintains homeostasis by regulating quiescent cell populations affected by tissue damage. © 2015. Published by The Company of Biologists Ltd.

Biomaterials in Relation to Dentistry.

PubMed

Deb, Sanjukta; Chana, Simran

2015-01-01

Dental caries remains a challenge in the improvement of oral health. It is the most common and widespread biofilm-dependent oral disease, resulting in the destruction of tooth structure by the acidic attack from cariogenic bacteria. The tooth is a heavily mineralised tissue, and both enamel and dentine can undergo demineralisation due to trauma or dietary conditions. The adult population worldwide affected by dental caries is enormous and despite significant advances in caries prevention and tooth restoration, treatments continue to pose a substantial burden to healthcare. Biomaterials play a vital role in the restoration of the diseased or damaged tooth structure and, despite providing reasonable outcomes, there are some concerns with clinical performance. Amalgam, the silver grey biomaterial that has been widely used as a restorative material in dentistry, is currently in throes of being phased out, especially with the Minimata convention and treaty being signed by a number of countries (January 2013; http://mercuryconvention.org/Convention/) that aims to control the anthropogenic release of mercury in the environment, which naturally impacts the use of amalgam, where mercury is a component. Thus, the development of alternative restoratives and restoration methods that are inexpensive, can be used under different climatic conditions, withstand storage and allow easy handling, the main prerequisites of dental biomaterials, is important. The potential for using biologically engineered tissue and consequent research to replace damaged tissues has also seen a quantum leap in the last decade. Ongoing research in regenerative treatments in dentistry includes alveolar ridge augmentation, bone tissue engineering and periodontal ligament replacement, and a future aim is bioengineering of the whole tooth. Research towards developing bioengineered teeth is well underway and identification of adult stem cell sources to make this a viable treatment is advancing; however, this topic is not in the scope of this chapter. Whilst research focuses on many different aspects, operative dentistry involves the wide use of restorative biomaterials; thus, the development of smart biomaterials to suit the current climes of minimally invasive dentistry is important. The concept of minimally invasive dentistry primarily promotes preservation of the natural tissue, and, thus, the prevention of disease or the advancement of procedures that allow early detection and interception of its progress with minimal tissue loss are of significance. This chapter presents, in brief, the current state of the art of direct restorative biomaterials and their role and future in the field of dentistry. Modern dental practice is highly reliant on the selection of appropriate materials for optimum function and benefit to the patient. Dentistry, perhaps, has the unique distinction of using the widest variety of materials, ranging from polymers, metals, ceramics, inorganic salts to composite materials. So far, aesthetics of restorative materials and their ability to perform in the harsh oral environment without undergoing changes in dimension and stability has been the major focus of materials used in dentistry. Despite advances in tissue engineering and regeneration in the field of regenerative medicine, this concept has found relatively limited application for enamel and dentine due to their limited ability to remodel, but research related to biomimetic approaches for the modification of dentine is a significant step. © 2015 S. Karger AG, Basel.

Accelerated Bone Repair After Plasma Laser Corticotomies

PubMed Central

Leucht, Philipp; Lam, Kentson; Kim, Jae-Beom; Mackanos, Mark A.; Simanovskii, Dmitrii M.; Longaker, Michael T.; Contag, Christopher H.; Schwettman, H Alan; Helms, Jill A.

2007-01-01

Objective: To reveal, on a cellular and molecular level, how skeletal regeneration of a corticotomy is enhanced when using laser-plasma mediated ablation compared with conventional mechanical tissue removal. Summary Background Data: Osteotomies are well-known for their most detrimental side effect: thermal damage. This thermal and mechanical trauma to adjacent bone tissue can result in the untoward consequences of cell death and eventually in a delay in healing. Methods: Murine tibial corticotomies were performed using a conventional saw and a Ti:Sapphire plasma-generated laser that removes tissue with minimal thermal damage. Our analyses began 24 hours after injury and proceeded to postsurgical day 6. We investigated aspects of wound repair ranging from vascularization, inflammation, cell proliferation, differentiation, and bone remodeling. Results: Histology of mouse corticotomy sites uncovered a significant difference in the onset of bone healing; whereas laser corticotomies showed abundant bone matrix deposition at postsurgical day 6, saw corticotomies only exhibited undifferentiated tissue. Our analyses uncovered that cutting bone with a saw caused denaturation of the collagen matrix due to thermal effects. This denatured collagen represented an unfavorable scaffold for subsequent osteoblast attachment, which in turn impeded deposition of a new bony matrix. The matrix degradation induced a prolonged inflammatory reaction at the cut edge to create a surface favorable for osteochondroprogenitor cell attachment. Laser corticotomies were absent of collagen denaturation, therefore osteochondroprogenitor cell attachment was enabled shortly after surgery. Conclusion: In summary, these data demonstrate that corticotomies performed with Ti:Sapphire lasers are associated with a reduced initial inflammatory response at the injury site leading to accelerated osteochondroprogenitor cell migration, attachment, differentiation, and eventually matrix deposition. PMID:17592303

Assessment of a Modified Acoustic Lens for Electromagnetic Shock Wave Lithotripters in a Swine Model

PubMed Central

Mancini, John G.; Neisius, Andreas; Smith, Nathan; Sankin, Georgy; Astroza, Gaston M.; Lipkin, Michael E.; Simmons, Walther N.; Preminger, Glenn M.; Zhong, Pei

2013-01-01

Purpose The acoustic lens of the Siemens Modularis electromagnetic (EM) shock wave lithotripter has been modified to produce a pressure waveform and focal zone more closely resembling that of the original Dornier HM3 device. Herein, we assess the newly designed acoustic lens in vivo in an animal model. Materials and Methods Stone fragmentation and tissue injury produced by the original and modified lenses of a Siemens lithotripter were evaluated in a swine model under equivalent acoustic pulse energy (~45 mJ) at 1 Hz pulse repetition frequency. Stone fragmentation was determined by the weight percent of stone fragments less than 2 mm. For tissue injury assessment, shock wave-treated kidneys were perfused, dehydrated, cast in paraffin wax and sectioned. Digital images were captured every 120 µm and processed to determine the functional renal volume damage. Results After 500 shocks, stone fragmentation efficiency produced by the original and modified lenses was 48 ± 12% and 52 ± 17% (p=0.60), respectively. However, after 2000 shocks, the modified lens showed significantly improved stone fragmentation of 86 ± 10%, compared to 72 ± 12% for the original lens (p=0.02). Tissue injury caused by the original and modified lenses was minimal at 0.57 ± 0.44% and 0.25 ± 0.25% (p=0.27), respectively. Conclusions With lens modification, the Siemens Modularis lithotripter demonstrates significantly improved stone fragmentation with minimal tissue injury at clinically relevant acoustic pulse energy. This new lens design could potentially be retrofitted to existing lithotripters, thereby improving the effectiveness of EM lithotripters. PMID:23485509

Folic Acid and Grape Seed Extract Prevent Azathioprine-induced Fetal Malformations and Renal Toxicity in Rats.

PubMed

El-Ashmawy, Ibrahim M; Bayad, Aida E

2016-12-01

Azathioprine (AZA) is an important drug commonly used in the therapy of the autoimmune system disorders. It induces many hazard effects that restrict its use. The present study was designed to investigate the influence of AZA on the fetal development and renal function and its co-administration with either folic acid (FA) or grape seed extract (GSE). The effects of administration of GSE or FA on AZA toxicity by gavage simultaneously for 4 weeks were studied by determining the changes in kidney histology, the glutathione level (GSH), and lipid per oxidation content as malondialdehyde in the kidney tissue. Additionally, their effects on the fetal development were investigated. Azathioprine induced a renal damage as indicated from the pronounced changes in histological structure, a significant increase in serum urea and creatinine, and malondialdehyde content in the kidney tissue. Meanwhile, the GSH activity was significantly decreased. Co-treatment with GSE significantly minimized the previously mentioned hazard effects of AZA by ameliorating the antioxidant activity. At this point, FA induced a nonsignificant protective activity. The results also revealed that administration of FA or GSE at 6th to 15th day of gestation did not altered fetal development. While, AZA administration clearly disturbed fetal development as indicated from a significant decrease in fetal weights. Furthermore, co-administration of both drugs significantly minimized similarly the hazards of AZA on the fetal development. It may be concluded that GSE and FA are a useful remedies. Maternal administrations of either both are protective agents against AZA-induced fetal malformations. Grape seed extract was more active than FA in potentiating the antioxidative defenses for controlling AZA-induced oxidative renal damages. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Damage to apparel layers and underlying tissue due to hand-gun bullets.

PubMed

Carr, Debra; Kieser, Jules; Mabbott, Alexander; Mott, Charlotte; Champion, Stephen; Girvan, Elizabeth

2014-01-01

Ballistic damage to the clothing of victims of gunshot wounds to the chest can provide useful forensic evidence. Anyone shot in the torso will usually be wearing clothing which will be damaged by the penetrating impact event and can reportedly be the source of some of the debris in the wound. Minimal research has previously been reported regarding the effect of bullets on apparel fabrics and underlying tissue. This paper examines the effect of ammunition (9 mm full metal jacket [FMJ] DM11 A1B2, 8.0 g; and soft point flat nose Remington R357M3, 10.2 g) on clothing layers that cover the torso (T-shirt, T-shirt plus hoodie, T-shirt plus denim jacket) and underlying structures represented by porcine thoracic wall (skin, underlying tissue, ribs). Impacts were recorded using a Phantom V12 high speed camera. Ejected bone debris was collected before wound tracts were dissected and measured; any debris found was recovered for further analysis. Size and mass of bony debris was recorded; fibre debris recovered from the wound and impact damage to fabrics were imaged using scanning electron microscopy (SEM). Remington R357M3 ammunition was characteristically associated with stellate fabric damage; individual fibres were less likely to show mushrooming. In contrast, 9 mm FMJ ammunition resulted in punch-out damage to fabric layers, with mushrooming of individual fibres being more common. Entry wound sizes were similar for both types of ammunition and smaller than the diameter of the bullet that caused them. In this work, the Remington R357M3 ammunition resulted in larger exit wounds due to the bullet construction which mushroomed. That fabric coverings did not affect the amount of bony debris produced is interesting, particularly given there was some evidence that apparel layers affected the size of the wound. Recent work has suggested that denim (representative of jeans) can exacerbate wounding caused by high-velocity bullet impacts to the thigh when the bullet does not impact the femur. That more bony debris was caused by Remington R357M3 rather than 9 mm FMJ ammunition was not surprising given the relative constructions of these two bullets, and is of interest to medical practitioners.

Effects of electrocautery on transvenous lead insulation materials.

PubMed

Lim, Kiam-Khiang; Reddy, Shantanu; Desai, Shrojal; Smelley, Matthew; Kim, Susan S; Beshai, John F; Lin, Albert C; Burke, Martin C; Knight, Bradley P

2009-04-01

Insulation defects are a leading cause of transvenous lead failure. The purpose of this study was to determine the effects of electrocautery on transvenous lead insulation materials. A preparation was done to simulate dissection of a transvenous lead from tissues. Radiofrequency energy was delivered using a standard cautery blade at outputs of 10, 20, and 30 W, for 3 and 6 seconds, using parallel and perpendicular blade orientations on leads with outermost insulations of silicone rubber, polyurethane, and silicone-polyurethane copolymer. Damage to each lead segment was classified after visual and microscopic analysis. Significant insulation damage occurred to almost all polyurethane leads. Full insulation breaches were observed with 30 W regardless of application duration with a parallel direction and with all power outputs with a perpendicular direction. Thermal insulation damage to copolymer insulation was similar to that of the polyurethane leads. In contrast, there was no thermal damage to silicone leads, regardless of the power output and duration of power delivery. However, mechanical insulation damage was observed to all silicone leads when at least 20 W was applied in a direction perpendicular to the lead. Polyurethane (PU55D) and copolymer materials have low thermal stability and are highly susceptible to thermal damage during cautery. Implanting physicians should be aware of the lead insulation materials being used during implant procedures and their properties. The use of direct contact cautery on transvenous leads should be minimized to avoid damage to the lead, especially on leads with polyurethane or copolymer outer insulations.

Modeling Soft Tissue Damage and Failure Using a Combined Particle/Continuum Approach.

PubMed

Rausch, M K; Karniadakis, G E; Humphrey, J D

2017-02-01

Biological soft tissues experience damage and failure as a result of injury, disease, or simply age; examples include torn ligaments and arterial dissections. Given the complexity of tissue geometry and material behavior, computational models are often essential for studying both damage and failure. Yet, because of the need to account for discontinuous phenomena such as crazing, tearing, and rupturing, continuum methods are limited. Therefore, we model soft tissue damage and failure using a particle/continuum approach. Specifically, we combine continuum damage theory with Smoothed Particle Hydrodynamics (SPH). Because SPH is a meshless particle method, and particle connectivity is determined solely through a neighbor list, discontinuities can be readily modeled by modifying this list. We show, for the first time, that an anisotropic hyperelastic constitutive model commonly employed for modeling soft tissue can be conveniently implemented within a SPH framework and that SPH results show excellent agreement with analytical solutions for uniaxial and biaxial extension as well as finite element solutions for clamped uniaxial extension in 2D and 3D. We further develop a simple algorithm that automatically detects damaged particles and disconnects the spatial domain along rupture lines in 2D and rupture surfaces in 3D. We demonstrate the utility of this approach by simulating damage and failure under clamped uniaxial extension and in a peeling experiment of virtual soft tissue samples. In conclusion, SPH in combination with continuum damage theory may provide an accurate and efficient framework for modeling damage and failure in soft tissues.

Modeling Soft Tissue Damage and Failure Using a Combined Particle/Continuum Approach

PubMed Central

Rausch, M. K.; Karniadakis, G. E.; Humphrey, J. D.

2016-01-01

Biological soft tissues experience damage and failure as a result of injury, disease, or simply age; examples include torn ligaments and arterial dissections. Given the complexity of tissue geometry and material behavior, computational models are often essential for studying both damage and failure. Yet, because of the need to account for discontinuous phenomena such as crazing, tearing, and rupturing, continuum methods are limited. Therefore, we model soft tissue damage and failure using a particle/continuum approach. Specifically, we combine continuum damage theory with Smoothed Particle Hydrodynamics (SPH). Because SPH is a meshless particle method, and particle connectivity is determined solely through a neighbor list, discontinuities can be readily modeled by modifying this list. We show, for the first time, that an anisotropic hyperelastic constitutive model commonly employed for modeling soft tissue can be conveniently implemented within a SPH framework and that SPH results show excellent agreement with analytical solutions for uniaxial and biaxial extension as well as finite element solutions for clamped uniaxial extension in 2D and 3D. We further develop a simple algorithm that automatically detects damaged particles and disconnects the spatial domain along rupture lines in 2D and rupture surfaces in 3D. We demonstrate the utility of this approach by simulating damage and failure under clamped uniaxial extension and in a peeling experiment of virtual soft tissue samples. In conclusion, SPH in combination with continuum damage theory may provide an accurate and efficient framework for modeling damage and failure in soft tissues. PMID:27538848

Biolasol: novel perfusion and preservation solution for kidneys.

PubMed

Cierpka, L; Ryszka, F; Dolińska, B; Smorąg, Z; Słomski, R; Wiaderkiewicz, R; Caban, A; Budziński, G; Oczkowicz, G; Wieczorek, J

2014-10-01

Biolasol solution (Pharmaceutical Research and Production Plant "Biochefa," Sosnowiec, Poland) is a novel extracellular perfusion and ex vivo hypothermic kidney preservation solution. It ensures maintenance of homeostasis, reduces tissue edema, has low viscosity, and allows the graft to preserve structural and functional integrity. It minimizes ischemia-reperfusion damage. Perfundates from control and transplanted kidneys flushed with Biolasol or ViaSpan solutions (Arkas, Warszawa, Poland) were analyzed. Parameters of serum and urine collected from 12 pigs after auto-transplantation were also analyzed. Renal medulla was investigated for structural alterations by analyzing hematoxylin and eosin-stained slides. The mean survival time of pigs after the auto-transplantation procedure was the measure for the novel Biolasol solution effectiveness. We observed a statistically significant decrease in marker enzyme levels alanine transaminase, aspartate transaminase, lactic dehydrogenase, and ions (Na and K) in pigs with grafts flushed with Biolasol. Histopathologic examination revealed that the renal cortex structure was not damaged after the use of Biolasol solution. Biolasol solution protects kidneys against ischemia damage and does not differ significantly from the "golden standard" ViaSpan solution.

Dynamics of retinal photocoagulation and rupture

NASA Astrophysics Data System (ADS)

Sramek, Christopher; Paulus, Yannis; Nomoto, Hiroyuki; Huie, Phil; Brown, Jefferson; Palanker, Daniel

2009-05-01

In laser retinal photocoagulation, short (<20 ms) pulses have been found to reduce thermal damage to the inner retina, decrease treatment time, and minimize pain. However, the safe therapeutic window (defined as the ratio of power for producing a rupture to that of mild coagulation) decreases with shorter exposures. To quantify the extent of retinal heating and maximize the therapeutic window, a computational model of millisecond retinal photocoagulation and rupture was developed. Optical attenuation of 532-nm laser light in ocular tissues was measured, including retinal pigment epithelial (RPE) pigmentation and cell-size variability. Threshold powers for vaporization and RPE damage were measured with pulse durations ranging from 1 to 200 ms. A finite element model of retinal heating inferred that vaporization (rupture) takes place at 180-190°C. RPE damage was accurately described by the Arrhenius model with activation energy of 340 kJ/mol. Computed photocoagulation lesion width increased logarithmically with pulse duration, in agreement with histological findings. The model will allow for the optimization of beam parameters to increase the width of the therapeutic window for short exposures.

Modeling electrical power absorption and thermally-induced biological tissue damage.

PubMed

Zohdi, T I

2014-01-01

This work develops a model for thermally induced damage from high current flow through biological tissue. Using the first law of thermodynamics, the balance of energy produced by the current and the energy absorbed by the tissue are investigated. The tissue damage is correlated with an evolution law that is activated upon exceeding a temperature threshold. As an example, the Fung material model is used. For certain parameter choices, the Fung material law has the ability to absorb relatively significant amounts of energy, due to its inherent exponential response character, thus, to some extent, mitigating possible tissue damage. Numerical examples are provided to illustrate the model's behavior.

Non-Fourier based thermal-mechanical tissue damage prediction for thermal ablation.

PubMed

Li, Xin; Zhong, Yongmin; Smith, Julian; Gu, Chengfan

2017-01-02

Prediction of tissue damage under thermal loads plays important role for thermal ablation planning. A new methodology is presented in this paper by combing non-Fourier bio-heat transfer, constitutive elastic mechanics as well as non-rigid motion of dynamics to predict and analyze thermal distribution, thermal-induced mechanical deformation and thermal-mechanical damage of soft tissues under thermal loads. Simulations and comparison analysis demonstrate that the proposed methodology based on the non-Fourier bio-heat transfer can account for the thermal-induced mechanical behaviors of soft tissues and predict tissue thermal damage more accurately than classical Fourier bio-heat transfer based model.

Non-Fourier based thermal-mechanical tissue damage prediction for thermal ablation

PubMed Central

Li, Xin; Zhong, Yongmin; Smith, Julian; Gu, Chengfan

2017-01-01

ABSTRACT Prediction of tissue damage under thermal loads plays important role for thermal ablation planning. A new methodology is presented in this paper by combing non-Fourier bio-heat transfer, constitutive elastic mechanics as well as non-rigid motion of dynamics to predict and analyze thermal distribution, thermal-induced mechanical deformation and thermal-mechanical damage of soft tissues under thermal loads. Simulations and comparison analysis demonstrate that the proposed methodology based on the non-Fourier bio-heat transfer can account for the thermal-induced mechanical behaviors of soft tissues and predict tissue thermal damage more accurately than classical Fourier bio-heat transfer based model. PMID:27690290

Relative binding affinity of carboxylate-, phosphonate-, and bisphosphonate-functionalized gold nanoparticles targeted to damaged bone tissue

NASA Astrophysics Data System (ADS)

Ross, Ryan D.; Cole, Lisa E.; Roeder, Ryan K.

2012-10-01

Functionalized Au NPs have received considerable recent interest for targeting and labeling cells and tissues. Damaged bone tissue can be targeted by functionalizing Au NPs with molecules exhibiting affinity for calcium. Therefore, the relative binding affinity of Au NPs surface functionalized with either carboxylate ( l-glutamic acid), phosphonate (2-aminoethylphosphonic acid), or bisphosphonate (alendronate) was investigated for targeted labeling of damaged bone tissue in vitro. Targeted labeling of damaged bone tissue was qualitatively verified by visual observation and backscattered electron microscopy, and quantitatively measured by the surface density of Au NPs using field-emission scanning electron microscopy. The surface density of functionalized Au NPs was significantly greater within damaged tissue compared to undamaged tissue for each functional group. Bisphosphonate-functionalized Au NPs exhibited a greater surface density labeling damaged tissue compared to glutamic acid- and phosphonic acid-functionalized Au NPs, which was consistent with the results of previous work comparing the binding affinity of the same functionalized Au NPs to synthetic hydroxyapatite crystals. Targeted labeling was enabled not only by the functional groups but also by the colloidal stability in solution. Functionalized Au NPs were stabilized by the presence of the functional groups, and were shown to remain well dispersed in ionic (phosphate buffered saline) and serum (fetal bovine serum) solutions for up to 1 week. Therefore, the results of this study suggest that bisphosphonate-functionalized Au NPs have potential for targeted delivery to damaged bone tissue in vitro and provide motivation for in vivo investigation.

Explicit formula of finite difference method to estimate human peripheral tissue temperatures during exposure to severe cold stress.

PubMed

Khanday, M A; Hussain, Fida

2015-02-01

During cold exposure, peripheral tissues undergo vasoconstriction to minimize heat loss to preserve the maintenance of a normal core temperature. However, vasoconstricted tissues exposed to cold temperatures are susceptible to freezing and frostbite-related tissue damage. Therefore, it is imperative to establish a mathematical model for the estimation of tissue necrosis due to cold stress. To this end, an explicit formula of finite difference method has been used to obtain the solution of Pennes' bio-heat equation with appropriate boundary conditions to estimate the temperature profiles of dermal and subdermal layers when exposed to severe cold temperatures. The discrete values of nodal temperature were calculated at the interfaces of skin and subcutaneous tissues with respect to the atmospheric temperatures of 25 °C, 20 °C, 15 °C, 5 °C, -5 °C and -10 °C. The results obtained were used to identify the scenarios under which various degrees of frostbite occur on the surface of skin as well as the dermal and subdermal areas. The explicit formula of finite difference method proposed in this model provides more accurate predictions as compared to other numerical methods. This model of predicting tissue temperatures provides researchers with a more accurate prediction of peripheral tissue temperature and, hence, the susceptibility to frostbite during severe cold exposure. Copyright © 2014 Elsevier Ltd. All rights reserved.

Feasibility of using optical coherence tomography to detect acute radiation-induced esophageal damage in small animal models

NASA Astrophysics Data System (ADS)

Jelvehgaran, Pouya; de Bruin, Daniel Martijn; Salguero, F. Javier; Borst, Gerben Roelof; Song, Ji-Ying; van Leeuwen, Ton G.; de Boer, Johannes F.; Alderliesten, Tanja; van Herk, Marcel

2018-04-01

Lung cancer survival is poor, and radiation therapy patients often suffer serious treatment side effects. The esophagus is particularly sensitive leading to acute radiation-induced esophageal damage (ARIED). We investigated the feasibility of optical coherence tomography (OCT) for minimally invasive imaging of the esophagus with high resolution (10 μm) to detect ARIED in mice. Thirty mice underwent cone-beam computed tomography imaging for initial setup assessment and dose planning followed by a single-dose delivery of 4.0, 10.0, 16.0, and 20.0 Gy on 5.0-mm spots, spaced 10.0 mm apart in the esophagus. They were repeatedly imaged using OCT up to three months postirradiation. We compared OCT findings with histopathology obtained three months postirradiation qualitatively and quantitatively using the contrast-to-background-noise ratio (CNR). Histopathology mostly showed inflammatory infiltration and edema at higher doses; OCT findings were in agreement with most of the histopathological reports. We were able to identify the ARIED on OCT as a change in tissue scattering and layer thickness. Our statistical analysis showed significant difference between the CNR values of healthy tissue, edema, and inflammatory infiltration. Overall, the average CNR for inflammatory infiltration and edema damages was 1.6-fold higher and 1.6-fold lower than for the healthy esophageal wall, respectively. Our results showed the potential role of OCT to detect and monitor the ARIED in mice, which may translate to humans.

Buccal Micronucleus Cytome Assay in Sickle Cell Disease

PubMed Central

Naga, Mallika Bokka Sri Satya; Gour, Shreya; Nallagutta, Nalini; Velidandla, Surekha; Manikya, Sangameshwar

2016-01-01

Introduction Sickle Cell Anaemia (SCA) is a commonly inherited blood disorder preceded by episodes of pain, chronic haemolytic anaemia and severe infections. The underlying phenomenon which causes this disease is the point mutation in the haemoglobin beta gene (Hbβ) found on chromosome 11 p. Increased oxidative stress leads to DNA damage. DNA damage occurring in such conditions can be studied by the buccal micronucleus cytome assay, which is a minimally invasive method for studying chromosomal instability, cell death and regenerative potential of human buccal tissue. Aim To evaluate genomic instability in patients with sickle cell disease by buccal micronucleus cytome assay. Materials and Methods The study included 40 sickle cell anemia patients (Group A) and 40 age and sex matched controls (Group B). Buccal swabs were collected and stained with Papanicolaou (PAP). Number of cells with micronucleus, binuclei, nuclear bud, pyknosis and karyolysis were counted in two groups as parameters for the evaluation of genome stability. Results All the analysis was done using t-test. A p-value of <0.001 was considered statistically significant. There was a statistically significant increase in micronuclei number in SCA patients when compared with controls. Karyolytic (un-nucleated) cell number in Group A was more than to those of the controls. Conclusion The results might suggest that patients with sickle cell anaemia have genome instability which is represented by the presence of micronuclei in the somatic cells. Presence of apoptotic cells might only indicate the bodily damage to the tissue as a result of the disease. PMID:27504413

Buccal Micronucleus Cytome Assay in Sickle Cell Disease.

PubMed

Naga, Mallika Bokka Sri Satya; Gour, Shreya; Nallagutta, Nalini; Ealla, Kranti Kiran Reddy; Velidandla, Surekha; Manikya, Sangameshwar

2016-06-01

Sickle Cell Anaemia (SCA) is a commonly inherited blood disorder preceded by episodes of pain, chronic haemolytic anaemia and severe infections. The underlying phenomenon which causes this disease is the point mutation in the haemoglobin beta gene (Hbβ) found on chromosome 11 p. Increased oxidative stress leads to DNA damage. DNA damage occurring in such conditions can be studied by the buccal micronucleus cytome assay, which is a minimally invasive method for studying chromosomal instability, cell death and regenerative potential of human buccal tissue. To evaluate genomic instability in patients with sickle cell disease by buccal micronucleus cytome assay. The study included 40 sickle cell anemia patients (Group A) and 40 age and sex matched controls (Group B). Buccal swabs were collected and stained with Papanicolaou (PAP). Number of cells with micronucleus, binuclei, nuclear bud, pyknosis and karyolysis were counted in two groups as parameters for the evaluation of genome stability. All the analysis was done using t-test. A p-value of <0.001 was considered statistically significant. There was a statistically significant increase in micronuclei number in SCA patients when compared with controls. Karyolytic (un-nucleated) cell number in Group A was more than to those of the controls. The results might suggest that patients with sickle cell anaemia have genome instability which is represented by the presence of micronuclei in the somatic cells. Presence of apoptotic cells might only indicate the bodily damage to the tissue as a result of the disease.

Virtual wall-based haptic-guided teleoperated surgical robotic system for single-port brain tumor removal surgery.

PubMed

Seung, Sungmin; Choi, Hongseok; Jang, Jongseong; Kim, Young Soo; Park, Jong-Oh; Park, Sukho; Ko, Seong Young

2017-01-01

This article presents a haptic-guided teleoperation for a tumor removal surgical robotic system, so-called a SIROMAN system. The system was developed in our previous work to make it possible to access tumor tissue, even those that seat deeply inside the brain, and to remove the tissue with full maneuverability. For a safe and accurate operation to remove only tumor tissue completely while minimizing damage to the normal tissue, a virtual wall-based haptic guidance together with a medical image-guided control is proposed and developed. The virtual wall is extracted from preoperative medical images, and the robot is controlled to restrict its motion within the virtual wall using haptic feedback. Coordinate transformation between sub-systems, a collision detection algorithm, and a haptic-guided teleoperation using a virtual wall are described in the context of using SIROMAN. A series of experiments using a simplified virtual wall are performed to evaluate the performance of virtual wall-based haptic-guided teleoperation. With haptic guidance, the accuracy of the robotic manipulator's trajectory is improved by 57% compared to one without. The tissue removal performance is also improved by 21% ( p < 0.05). The experiments show that virtual wall-based haptic guidance provides safer and more accurate tissue removal for single-port brain surgery.

Estimating Tool–Tissue Forces Using a 3-Degree-of-Freedom Robotic Surgical Tool

PubMed Central

Zhao, Baoliang; Nelson, Carl A.

2016-01-01

Robot-assisted minimally invasive surgery (MIS) has gained popularity due to its high dexterity and reduced invasiveness to the patient; however, due to the loss of direct touch of the surgical site, surgeons may be prone to exert larger forces and cause tissue damage. To quantify tool–tissue interaction forces, researchers have tried to attach different kinds of sensors on the surgical tools. This sensor attachment generally makes the tools bulky and/or unduly expensive and may hinder the normal function of the tools; it is also unlikely that these sensors can survive harsh sterilization processes. This paper investigates an alternative method by estimating tool–tissue interaction forces using driving motors' current, and validates this sensorless force estimation method on a 3-degree-of-freedom (DOF) robotic surgical grasper prototype. The results show that the performance of this method is acceptable with regard to latency and accuracy. With this tool–tissue interaction force estimation method, it is possible to implement force feedback on existing robotic surgical systems without any sensors. This may allow a haptic surgical robot which is compatible with existing sterilization methods and surgical procedures, so that the surgeon can obtain tool–tissue interaction forces in real time, thereby increasing surgical efficiency and safety. PMID:27303591

Low-level lasers affect uncoupling protein gene expression in skin and skeletal muscle tissues

NASA Astrophysics Data System (ADS)

Canuto, K. S.; Sergio, L. P. S.; Paoli, F.; Mencalha, A. L.; Fonseca, A. S.

2016-03-01

Wavelength, frequency, power, fluence, and emission mode determine the photophysical, photochemical, and photobiological responses of biological tissues to low-level lasers. Free radicals are involved in these responses acting as second messengers in intracellular signaling processes. Irradiated cells present defenses against these chemical species to avoid unwanted effects, such as uncoupling proteins (UCPs), which are part of protective mechanisms and minimize the effects of free radical generation in mitochondria. In this work UCP2 and UCP3 mRNA gene relative expression in the skin and skeletal muscle tissues of Wistar rats exposed to low-level red and infrared lasers was evaluated. Samples of the skin and skeletal muscle tissue of Wistar rats exposed to low-level red and infrared lasers were withdrawn for total RNA extraction, cDNA synthesis, and the evaluation of gene expression by quantitative polymerase chain reaction. UCP2 and UCP3 mRNA expression was differently altered in skin and skeletal muscle tissues exposed to lasers in a wavelength-dependent effect, with the UCP3 mRNA expression dose-dependent. Alteration on UCP gene expression could be part of the biostimulation effect and is necessary to make cells exposed to red and infrared low-level lasers more resistant or capable of adapting in damaged tissues or diseases.

Estimating Tool-Tissue Forces Using a 3-Degree-of-Freedom Robotic Surgical Tool.

PubMed

Zhao, Baoliang; Nelson, Carl A

2016-10-01

Robot-assisted minimally invasive surgery (MIS) has gained popularity due to its high dexterity and reduced invasiveness to the patient; however, due to the loss of direct touch of the surgical site, surgeons may be prone to exert larger forces and cause tissue damage. To quantify tool-tissue interaction forces, researchers have tried to attach different kinds of sensors on the surgical tools. This sensor attachment generally makes the tools bulky and/or unduly expensive and may hinder the normal function of the tools; it is also unlikely that these sensors can survive harsh sterilization processes. This paper investigates an alternative method by estimating tool-tissue interaction forces using driving motors' current, and validates this sensorless force estimation method on a 3-degree-of-freedom (DOF) robotic surgical grasper prototype. The results show that the performance of this method is acceptable with regard to latency and accuracy. With this tool-tissue interaction force estimation method, it is possible to implement force feedback on existing robotic surgical systems without any sensors. This may allow a haptic surgical robot which is compatible with existing sterilization methods and surgical procedures, so that the surgeon can obtain tool-tissue interaction forces in real time, thereby increasing surgical efficiency and safety.

Assessment of penetrating thermal tissue damage/spread associated with PhotonBlade™, Valleylab™ Pencil, Valleylab™ EDGE™ Coated Pencil, PlasmaBlade® 3.0S and PlasmaBlade® 4.0 for intraoperative tissue dissection using the fresh extirpated porcine muscle model

NASA Astrophysics Data System (ADS)

Bennett, Haydon E.; Taylor, Scott D.; Fugett, James H.; Shrout, Joshua L.; Davison, Paul O.; Ryan, S. Eric; Coad, James E.

2017-02-01

Penetrating thermal tissue damage/spread is an important aspect of many electrosurgical devices and correlates with effective tissue cutting, hemostasis, preservation of adjacent critical structures and tissue healing. This study compared the thermal damage/spread associated with the PhotonBlade, Valleylab Pencil, Valleylab EDGE Coated Pencil, PlasmaBlade 3.0S and PlasmaBlade 4.0, when performing a single pass dynamic tissue cut in fresh extirpated porcine longissimus muscle. These devices were used in a fashion that emulated their use in the clinical setting. Each device's thermal damage/spread, at Minimum, Median and Maximum power input settings, was assessed with nitroblue tetrazolium viability staining in the WVU Pathology Laboratory for Translational Medicine. The thermal damage/spread associated with the PhotonBlade was compared with the other devices tested based on the individual treatment results (n=179 cuts combined). In summary, the PhotonBlade overall demonstrated the least penetrating thermal tissue damage/spread, followed by the PlasmaBlade 4.0, then Valleylab Pencil and PlasmaBlade 3.0S and then Valleylab EDGE Coated Pencil in order of increasing thermal damage/spread depths.

Thermal modeling of lesion growth with radiofrequency ablation devices

PubMed Central

Chang, Isaac A; Nguyen, Uyen D

2004-01-01

Background Temperature is a frequently used parameter to describe the predicted size of lesions computed by computational models. In many cases, however, temperature correlates poorly with lesion size. Although many studies have been conducted to characterize the relationship between time-temperature exposure of tissue heating to cell damage, to date these relationships have not been employed in a finite element model. Methods We present an axisymmetric two-dimensional finite element model that calculates cell damage in tissues and compare lesion sizes using common tissue damage and iso-temperature contour definitions. The model accounts for both temperature-dependent changes in the electrical conductivity of tissue as well as tissue damage-dependent changes in local tissue perfusion. The data is validated using excised porcine liver tissues. Results The data demonstrate the size of thermal lesions is grossly overestimated when calculated using traditional temperature isocontours of 42°C and 47°C. The computational model results predicted lesion dimensions that were within 5% of the experimental measurements. Conclusion When modeling radiofrequency ablation problems, temperature isotherms may not be representative of actual tissue damage patterns. PMID:15298708

Aag DNA Glycosylase Promotes Alkylation-Induced Tissue Damage Mediated by Parp1

PubMed Central

Calvo, Jennifer A.; Moroski-Erkul, Catherine A.; Lake, Annabelle; Eichinger, Lindsey W.; Shah, Dharini; Jhun, Iny; Limsirichai, Prajit; Bronson, Roderick T.; Christiani, David C.; Meira, Lisiane B.; Samson, Leona D.

2013-01-01

Alkylating agents comprise a major class of front-line cancer chemotherapeutic compounds, and while these agents effectively kill tumor cells, they also damage healthy tissues. Although base excision repair (BER) is essential in repairing DNA alkylation damage, under certain conditions, initiation of BER can be detrimental. Here we illustrate that the alkyladenine DNA glycosylase (AAG) mediates alkylation-induced tissue damage and whole-animal lethality following exposure to alkylating agents. Aag-dependent tissue damage, as observed in cerebellar granule cells, splenocytes, thymocytes, bone marrow cells, pancreatic β-cells, and retinal photoreceptor cells, was detected in wild-type mice, exacerbated in Aag transgenic mice, and completely suppressed in Aag −/− mice. Additional genetic experiments dissected the effects of modulating both BER and Parp1 on alkylation sensitivity in mice and determined that Aag acts upstream of Parp1 in alkylation-induced tissue damage; in fact, cytotoxicity in WT and Aag transgenic mice was abrogated in the absence of Parp1. These results provide in vivo evidence that Aag-initiated BER may play a critical role in determining the side-effects of alkylating agent chemotherapies and that Parp1 plays a crucial role in Aag-mediated tissue damage. PMID:23593019

Ultrasound elastographic imaging of thermal lesions and temperature profiles during radiofrequency ablation

NASA Astrophysics Data System (ADS)

Techavipoo, Udomchai

Manual palpation to sense variations in tissue stiffness for disease diagnosis has been regularly performed by clinicians for centuries. However, it is generally limited to large and superficial structures and the ability of the physician performing the palpation. Imaging of tissue stiffness or elastic properties via the aid of modern imaging such as ultrasound and magnetic resonance imaging, referred to as elastography, enhances the capability for disease diagnosis. In addition, elastography could be used for monitoring tissue response to minimally invasive ablative therapies, which are performed percutaneously to destruct tumors with minimum damage to surrounding tissue. Monitoring tissue temperature during ablation is another approach to estimate tissue damage. The ultimate goal of this dissertation is to improve the image quality of elastograms and temperature profiles for visualizing thermal lesions during and after ablative therapies. Elastographic imaging of thermal lesions is evaluated by comparison of sizes, shapes, and volumes with the results obtained using gross pathology. Semiautomated segmentation of lesion boundaries on elastograms is also developed. It provides comparable results to those with manual segmentation. Elastograms imaged during radiofrequency ablation in vitro show that the impact of gas bubbles during ablation on the ability to delineate the thermal lesion is small. Two novel methods to reduce noise artifacts in elastograms, and an accurate estimation of displacement vectors are proposed. The first method applies wavelet-denoising algorithms to the displacement estimates. The second method utilizes angular compounding of the elastograms generated using ultrasound signal frames acquired from different insonification angles. These angular frames are also utilized to estimate all tissue displacement vector components in response to a deformation. These enable the generation of normal and shear strain elastograms and Poisson's ratio elastograms, which provide additional valuable information for disease diagnosis. Finally, measurements of temperature dependent variables, including sound speed, attenuation coefficient, and thermal expansion in canine liver tissue, are performed. This information is necessary for the estimation of the temperature profile during ablation. A mapping function between the gradient of timeshifts and tissue temperature is calculated using this information and subsequently applied to estimate temperature profiles.

Decay-Accelerating Factor Mitigates Controlled Hemorrhage-Instigated Intestinal and Lung Tissue Damage and Hyperkalemia in Swine

DTIC Science & Technology

2011-07-01

Decay-Accelerating Factor Mitigates Controlled Hemorrhage- Instigated Intestinal and Lung Tissue Damage and Hyperkalemia in Swine Jurandir J. Dalle...DAF treatment improved hemorrhage- induced hyperkalemia . The protective effects of DAF appear to be related to its ability to reduce tissue complement...Decay-accelerating factor mitigates controlled hemorrhage-instigated intestinal and lung tissue damage and hyperkalemia in swine 5a. CONTRACT NUMBER

Recent Advances in Tissue Engineering Strategies for the Treatment of Joint Damage.

PubMed

Stephenson, Makeda K; Farris, Ashley L; Grayson, Warren L

2017-08-01

While the clinical potential of tissue engineering for treating joint damage has yet to be realized, research and commercialization efforts in the field are geared towards overcoming major obstacles to clinical translation, as well as towards achieving engineered grafts that recapitulate the unique structures, function, and physiology of the joint. In this review, we describe recent advances in technologies aimed at obtaining biomaterials, stem cells, and bioreactors that will enable the development of effective tissue-engineered treatments for repairing joint damage. 3D printing of scaffolds is aimed at improving the mechanical structure and microenvironment necessary for bone regeneration within a damaged joint. Advances in our understanding of stem cell biology and cell manufacturing processes are informing translational strategies for the therapeutic use of allogeneic and autologous cells. Finally, bioreactors used in combination with cells and biomaterials are promising strategies for generating large tissue grafts for repairing damaged tissues in pre-clinical models. Together, these advances along with ongoing research directions are making tissue engineering increasingly viable for the treatment of joint damage.

Lowered threshold energy for femtosecond laser induced optical breakdown in a water based eye model by aberration correction with adaptive optics.

PubMed

Hansen, Anja; Géneaux, Romain; Günther, Axel; Krüger, Alexander; Ripken, Tammo

2013-06-01

In femtosecond laser ophthalmic surgery tissue dissection is achieved by photodisruption based on laser induced optical breakdown. In order to minimize collateral damage to the eye laser surgery systems should be optimized towards the lowest possible energy threshold for photodisruption. However, optical aberrations of the eye and the laser system distort the irradiance distribution from an ideal profile which causes a rise in breakdown threshold energy even if great care is taken to minimize the aberrations of the system during design and alignment. In this study we used a water chamber with an achromatic focusing lens and a scattering sample as eye model and determined breakdown threshold in single pulse plasma transmission loss measurements. Due to aberrations, the precise lower limit for breakdown threshold irradiance in water is still unknown. Here we show that the threshold energy can be substantially reduced when using adaptive optics to improve the irradiance distribution by spatial beam shaping. We found that for initial aberrations with a root-mean-square wave front error of only one third of the wavelength the threshold energy can still be reduced by a factor of three if the aberrations are corrected to the diffraction limit by adaptive optics. The transmitted pulse energy is reduced by 17% at twice the threshold. Furthermore, the gas bubble motions after breakdown for pulse trains at 5 kilohertz repetition rate show a more transverse direction in the corrected case compared to the more spherical distribution without correction. Our results demonstrate how both applied and transmitted pulse energy could be reduced during ophthalmic surgery when correcting for aberrations. As a consequence, the risk of retinal damage by transmitted energy and the extent of collateral damage to the focal volume could be minimized accordingly when using adaptive optics in fs-laser surgery.

Lowered threshold energy for femtosecond laser induced optical breakdown in a water based eye model by aberration correction with adaptive optics

PubMed Central

Hansen, Anja; Géneaux, Romain; Günther, Axel; Krüger, Alexander; Ripken, Tammo

2013-01-01

In femtosecond laser ophthalmic surgery tissue dissection is achieved by photodisruption based on laser induced optical breakdown. In order to minimize collateral damage to the eye laser surgery systems should be optimized towards the lowest possible energy threshold for photodisruption. However, optical aberrations of the eye and the laser system distort the irradiance distribution from an ideal profile which causes a rise in breakdown threshold energy even if great care is taken to minimize the aberrations of the system during design and alignment. In this study we used a water chamber with an achromatic focusing lens and a scattering sample as eye model and determined breakdown threshold in single pulse plasma transmission loss measurements. Due to aberrations, the precise lower limit for breakdown threshold irradiance in water is still unknown. Here we show that the threshold energy can be substantially reduced when using adaptive optics to improve the irradiance distribution by spatial beam shaping. We found that for initial aberrations with a root-mean-square wave front error of only one third of the wavelength the threshold energy can still be reduced by a factor of three if the aberrations are corrected to the diffraction limit by adaptive optics. The transmitted pulse energy is reduced by 17% at twice the threshold. Furthermore, the gas bubble motions after breakdown for pulse trains at 5 kilohertz repetition rate show a more transverse direction in the corrected case compared to the more spherical distribution without correction. Our results demonstrate how both applied and transmitted pulse energy could be reduced during ophthalmic surgery when correcting for aberrations. As a consequence, the risk of retinal damage by transmitted energy and the extent of collateral damage to the focal volume could be minimized accordingly when using adaptive optics in fs-laser surgery. PMID:23761849

Penetration and perforation of skin by bullets and missiles. A review of the literature.

PubMed

DiMaio, V J

1981-06-01

A review of the literature on perforation of skin by bullets and missiles indicates that there is a range of velocity below which a missile cannot perforate the skin. Velocities of between 38.1 and 61.6 meters/second (125 and 202 ft./second) will produce at least minimal damage to the surface of the skin, though without perforation. In order for a missile to perforate the skin and enter the underlying subcutaneous tissue and muscle, a minimum velocity in the order of 70 meters/second (230 ft./second) is necessary with an energy/area of presentation of approximately 2.1 m-kg/cm2.

High-intensity focused ultrasound in the treatment of breast tumours.

PubMed

Peek, Mirjam C L; Wu, Feng

2018-01-01

High-intensity focused ultrasound (HIFU) is a minimally invasive technique that has been used for the treatment of both benign and malignant tumours. With HIFU, an ultrasound (US) beam propagates through soft tissue as a high-frequency pressure wave. The US beam is focused at a small target volume, and due to the energy building up at this site, the temperature rises, causing coagulative necrosis and protein denaturation within a few seconds. HIFU is capable of providing a completely non-invasive treatment without causing damage to the directly adjacent tissues. HIFU can be either guided by US or magnetic resonance imaging (MRI). Guided imaging is used to plan the treatment, detect any movement during the treatment and monitor response in real-time. This review describes the history of HIFU, the HIFU technique, available devices and gives an overview of the published literature in the treatment of benign and malignant breast tumours with HIFU.

Near-IR-induced dissociation of thermally-sensitive star polymers.

PubMed

Dai, Yuqiong; Sun, Hao; Pal, Sunirmal; Zhang, Yunlu; Park, Sangwoo; Kabb, Christopher P; Wei, Wei David; Sumerlin, Brent S

2017-03-01

Responsive systems sensitive to near-infrared (NIR) light are promising for triggered release due to efficient deep tissue penetration of NIR irradiation relative to higher energy sources ( e.g. , UV), allowing for spatiotemporal control over triggering events with minimal potential for tissue damage. Herein, we report star polymers containing thermally-labile azo linkages that dissociate during conventional heating or during localized heating via the photothermal effect upon NIR irradiation. Controlled release during conventional heating was investigated for the star polymers loaded with a model dye, with negligible release being observed at 25 °C and >80% release at 90 °C. Star polymers co-loaded with NIR-responsive indocyanine green showed rapid dye release upon NIR irradiation ( λ ≥ 715 nm) due to the photothermally-induced degradation of azo linkages within the cores of the star polymers. This approach provides access to a new class of delivery and release systems that can be triggered by noninvasive external stimulation.

Ho:YAG laser arthroscopy of the knee

NASA Astrophysics Data System (ADS)

Sisto, Domenick J.; Blazina, Martin E.; Hirsh, Linda C.

1994-09-01

The HO:YAG laser is a near-contact laser with a capacity to ablate or cut tissues. The ablation function allows the surgeon to remove meniscal tissue, lyse and resect adhesions, melt loose bodies, and dissolve inflamed synovium. The cutting function of the laser is utilized to perform a lateral release or resect torn menisci. The laser can also be utilized to drill holes in Grade IV chondromalacic lesions to initiate a healing response. The laser has been embraced by orthopaedic surgeons because of its shape and versatility. The tip is only 2 mm wide and can be delivered into the tight posterior compartments of the knee with no damaging contact with the articular surfaces. The laser coagulates as it works and bleeding is minimized. The laser can function both as a cutting and ablating tool. The laser can also drill holes into subchondral bone to, hopefully, initiate a healing response.

Management of severe open ankle-foot trauma by a simple external fixation technique: an alternative during war and in resource-poor and low-technology environments.

PubMed

Pedrini, Gianpaolo; Cardi, Maurizio; Landini, Alberto; Strada, Gino

2011-03-01

Severe open foot and ankle injuries are still a challenge for the orthopaedic surgeon. Their treatment is even more difficult in third world countries and in war settings where high-energy trauma with severe soft tissue damage is more frequent. Lack of equipment, poor resources and hygiene, and different cultural systems make most of the standard proposed treatments difficult to apply. The authors describe an inexpensive, rapid, minimally invasive, and easy-to-apply external fixation technique for the treatment of severe open ankle-foot fractures. With the main goal of soft tissue management rather than definitive treatment of any bony injuries, this technique was developed over time during many consecutive missions in Sierra Leone and Afghanistan as an alternative to more appropriate treatments with surprisingly satisfactory short- and long-term results.

Piezosurgery in implant dentistry

PubMed Central

Stübinger, Stefan; Stricker, Andres; Berg, Britt-Isabelle

2015-01-01

Piezosurgery, or the use of piezoelectric devices, is being applied increasingly in oral and maxillofacial surgery. The main advantages of this technique are precise and selective cuttings, the avoidance of thermal damage, and the preservation of soft-tissue structures. Through the application of piezoelectric surgery, implant-site preparation, bone grafting, sinus-floor elevation, edentulous ridge splitting or the lateralization of the inferior alveolar nerve are very technically feasible. This clinical overview gives a short summary of the current literature and outlines the advantages and disadvantages of piezoelectric bone surgery in implant dentistry. Overall, piezoelectric surgery is superior to other methods that utilize mechanical instruments. Handling of delicate or compromised hard- and soft-tissue conditions can be performed with less risk for the patient. With respect to current and future innovative surgical concepts, piezoelectric surgery offers a wide range of new possibilities to perform customized and minimally invasive osteotomies. PMID:26635486

Phototoxicity to the retina: mechanisms of damage.

PubMed

Glickman, Randolph D

2002-01-01

Light damage to the retina occurs through three general mechanisms involving thermal, mechanical, or photochemical effects. The particular mechanism activated depends on the wavelength and exposure duration of the injuring light. The transitions between the various light damage mechanism may overlap to some extent. Energy confinement is a key concept in understanding or predicting the type of damage mechanism produced by a given light exposure. As light energy (either from a laser or an incoherent source) is deposited in the retina, its penetration through, and its absorption in, various tissue compartments is determined by its wavelength. Strongly absorbing tissue components will tend to "concentrate" the light energy. The effect of absorbed light energy largely depends on the rate of energy deposition, which is correlated with the exposure duration. If the rate of energy deposition is too low to produce an appreciable temperature increase in the tissue, then any resulting tissue damage necessarily occurs because of chemical (oxidative) reactions induced by absorption of energetic photons (photochemical damage). If the rate of energy deposition is faster than the rate of thermal diffusion (thermal confinement), then the temperature of the exposed tissue rises. If a critical temperature is reached (typically about 10 degrees C above basal), then thermal damage occurs. If the light energy is deposited faster than mechanical relaxation can occur (stress confinement), then a thermoelastic pressure wave is produced, and tissue is disrupted by shear forces or by cavitation-nonlinear effects. Very recent evidence suggests that ultrashort laser pulses can produce tissue damage through nonlinear and photochemical mechanisms; the latter because of two-photon excitation of cellular chromophores. In addition to tissue damage caused directly by light absorption, light toxicity can be produced by the presence of photosensitizing agents. Drugs excited to reactive states by ultraviolet (UV) or visible light produce damage by type I (free radical) and type II (oxygen dependent) mechanisms. Some commonly used drugs, such as certain antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and psychotherapeutic agents, as well as some popular herbal medicines, can produce ocular phototoxicity. Specific cellular effects and damage end points characteristic of light damage mechanisms are described.

Investigation of the effects of acrylamide applied during pregnancy on fetal brain development in rats and protective role of the vitamin E.

PubMed

Erdemli, M E; Turkoz, Y; Altinoz, E; Elibol, E; Dogan, Z

2016-12-01

A liberal amount of acrylamide (AA) is produced as a result of frying or baking foods in high temperatures, and individuals take certain amounts of AA everyday by consuming these food items. Pregnant women are also exposed to AA originating from food during pregnancy and their fetus are probably affected. The rats were divided into five different groups: control (C), corn oil (CO), vitamin E (Vit E), AA, and Vit E + AA, with eight pregnant rats in each group. On the 20th day of pregnancy, fetuses were removed and brain tissues of fetuses were examined for biochemical and histological changes. AA caused degeneration in neuron structures in fetal brain tissue and caused hemorrhagic damages; dramatically decreased brain-derived neurotrophic factor levels; increased malondialdehyde, total oxidant capacity levels; and decreased reduced glutathione and total antioxidant capacity levels (p < 0.05). On the other hand, it was determined that the Vit E, a neuroprotectant and a powerful antioxidant, suppressed the effects of AA on fetal development and fetal brain tissue damage for the above-mentioned parameters (p < 0.05). It is recommended to consume food containing Vit E as a protection to minimize the toxic effects of food-oriented AA on fetus development due to the widespread nature of fast-food culture in today's life and the impossibility of protection from AA toxicity. © The Author(s) 2016.

Perivascular iron deposits are associated with protein nitration in cerebral experimental autoimmune encephalomyelitis.

PubMed

Sands, Scott A; Williams, Rachel; Marshall, Sylvester; LeVine, Steven M

2014-10-17

Nitration of proteins, which is thought to be mediated by peroxynitrite, is a mechanism of tissue damage in multiple sclerosis (MS). However, protein nitration can also be catalyzed by iron, heme or heme-associated molecules independent of peroxynitrite. Since microhemorrhages and perivascular iron deposits are present in the CNS of MS patients, we sought to determine if iron is associated with protein nitration. A cerebral model of experimental autoimmune encephalomyelitis (cEAE) was utilized since this model has been shown to have perivascular iron deposits similar to those present in MS. Histochemical staining for iron was used together with immunohistochemistry for nitrotyrosine, eNOS, or iNOS on cerebral sections. Leakage of the blood-brain barrier (BBB) was studied by albumin immunohistochemistry. Iron deposits were colocalized with nitrotyrosine staining around vessels in cEAE mice while control animals revealed minimal staining. This finding supports the likelihood that nitrotyrosine formation was catalyzed by iron or iron containing molecules. Examples of iron deposits were also observed in association with eNOS and iNOS, which could be one source of substrates for this reaction. Extravasation of albumin was present in cEAE mice, but not in control animals. Extravasated albumin may act to limit tissue injury by binding iron and/or heme as well as being a target of nitration, but the protection is incomplete. In summary, iron-catalyzed nitration of proteins is a likely mechanism of tissue damage in MS. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Preliminary evaluation of several disinfection/sterilization techniques for use with microdialysis probes.

PubMed

Huff, Jacquelyn K; Bresnahan, James F; Davies, Malonne I

2003-06-06

This study evaluated the suitability of some disinfection and sterilization methods for use with microdialysis probes. Disinfection or sterilization should minimize the tissue inflammatory reaction and improve the long-term health of rats on study and ensure the quality of data obtained by microdialysis sampling. Furthermore, the treatment should not negatively impact probe integrity or sampling performance. The techniques chosen for evaluation included two disinfection methods (70% ethanol and a commercial contact lens solution) and two sterilization methods (hydrogen peroxide plasma, and e-beam radiation). Linear microdialysis probes treated by these processes were compared to untreated probes removed from the manufacturer's packaging as if sterile (the control group). The probes were aseptically implanted in the livers of rats and monitored for 72 hours. The parameters chosen to evaluate probe performance were relative sample mass recovery and the relative in vivo extraction efficiency of the probe for caffeine. Post mortem bacterial counts and histopathology examination of liver tissue were also conducted. The probes remained intact and functional for the entire study period. The methods tested did not acutely alter the probes although hydrogen peroxide plasma and contact lens solution groups showed reduced extraction efficiencies. Minimal tissue damage was observed surrounding the probes and acute inflammatory reaction was mild to moderate. Low numbers of bacterial colonies from the implantation sites indicates that the health of animals in this study was not impaired. This was also true for the control group (untreated probe).

Apoptosis Modulation in the Immune System Reveals a Role of Neutrophils in Tissue Damage in a Murine Model of Chlamydial Genital Infection.

PubMed

Zortel, Tom; Schmitt-Graeff, Annette; Kirschnek, Susanne; Häcker, Georg

2018-05-05

Chlamydial infection frequently causes damage to the female genital tract. The precise mechanisms of chlamydial clearance and tissue damage are unknown, but studies suggest immunopathology with a particular role of neutrophils. The goal of this study was to understand the contribution of the immune system, in particular neutrophils. Using Chlamydia muridarum, we infected mice with a prolonged immune response due to expression of B-cell lymphoma 2 (Bcl-2) in hematopoietic cells (Bcl-2 mice), and mice where mature neutrophils are lacking due to the deletion of Myeloid cell leukemia 1 (Mcl-1) in myeloid cells (LysM-cre-mcl-1-flox mice; Mcl-1 mice). We monitored bacterial clearance, cellular infiltrate, and long-term tissue damage. Both mutant strains showed slightly delayed clearance of the acute infection. Bcl-2 mice had a strongly increased inflammatory infiltrate concerning almost all cell lineages. The infection of Bcl-2 mice caused increased tissue damage. The loss of neutrophils in Mcl-1 mice was associated with substantial quantitative and qualitative alterations of the inflammatory infiltrate. Mcl-1 mice had higher chlamydial burden and reduced tissue damage, including lower incidence of hydrosalpinx and less uterine dilation. Inhibition of apoptosis in the hematopoietic system increases inflammation and tissue damage. Neutrophils have broad functions, including a role in chlamydial clearance and in tissue destruction.

Injury and immune response: applying the danger theory to mosquitoes

PubMed Central

Moreno-García, Miguel; Recio-Tótoro, Benito; Claudio-Piedras, Fabiola; Lanz-Mendoza, Humberto

2014-01-01

The insect immune response can be activated by the recognition of both non-self and molecular by-products of tissue damage. Since pathogens and tissue damage usually arise at the same time during infection, the specific mechanisms of the immune response to microorganisms, and to tissue damage have not been unraveled. Consequently, some aspects of damage caused by microorganisms in vector-borne arthropods have been neglected. We herein reassess the Anopheles–Plasmodium interaction, incorporating Matzinger’s danger/damage hypothesis and George Salt’s injury assumptions. The invasive forms of the parasite cross the peritrophic matrix and midgut epithelia to reach the basal lamina and differentiate into an oocyst. The sporozoites produced in the oocyst are released into the hemolymph, and from there enter the salivary gland. During parasite development, wounds to midgut tissue and the basement membrane are produced. We describe the response of the different compartments where the parasite interacts with the mosquito. In the midgut, the response includes the expression of antimicrobial peptides, production of reactive oxygen species, and possible activation of midgut regenerative cells. In the basal membrane, wound repair mainly involves the production of molecules and the recruitment of hemocytes. We discuss the susceptibility to damage in tissues, and how the place and degree of damage may influence the differential response and the expression of damage associated molecular patterns (DAMPs). Knowledge about damage caused by parasites may lead to a deeper understanding of the relevance of tissue damage and the immune response it generates, as well as the origins and progression of infection in this insect–parasite interaction. PMID:25250040

Dose-rate plays a significant role in synchrotron radiation X-ray-induced damage of rodent testes.

PubMed

Chen, Heyu; Wang, Ban; Wang, Caixia; Cao, Wei; Zhang, Jie; Ma, Yingxin; Hong, Yunyi; Fu, Shen; Wu, Fan; Ying, Weihai

2016-01-01

Synchrotron radiation (SR) X-ray has significant potential for applications in medical imaging and cancer treatment. However, the mechanisms underlying SR X-ray-induced tissue damage remain unclear. Previous studies on regular X-ray-induced tissue damage have suggested that dose-rate could affect radiation damage. Because SR X-ray has exceedingly high dose-rate compared to regular X-ray, it remains to be determined if dose-rate may affect SR X-ray-induced tissue damage. We used rodent testes as a model to investigate the role of dose-rate in SR X-ray-induced tissue damage. One day after SR X-ray irradiation, we determined the effects of the irradiation of the same dosage at two different dose-rates, 0.11 Gy/s and 1.1 Gy/s, on TUNEL signals, caspase-3 activation and DNA double-strand breaks (DSBs) of the testes. Compared to those produced by the irradiation at 0.11 Gy/s, irradiation at 1.1 Gy/s produced higher levels of DSBs, TUNEL signals, and caspase-3 activation in the testes. Our study has provided the first evidence suggesting that dose-rate could be a significant factor in SR X-ray-induced tissue damage, which may establish a valuable base for utilizing this factor to manipulate the tissue damage in SR X-ray-based medical applications.

Dose-rate plays a significant role in synchrotron radiation X-ray-induced damage of rodent testes

PubMed Central

Chen, Heyu; Wang, Ban; Wang, Caixia; Cao, Wei; Zhang, Jie; Ma, Yingxin; Hong, Yunyi; Fu, Shen; Wu, Fan; Ying, Weihai

2016-01-01

Synchrotron radiation (SR) X-ray has significant potential for applications in medical imaging and cancer treatment. However, the mechanisms underlying SR X-ray-induced tissue damage remain unclear. Previous studies on regular X-ray-induced tissue damage have suggested that dose-rate could affect radiation damage. Because SR X-ray has exceedingly high dose-rate compared to regular X-ray, it remains to be determined if dose-rate may affect SR X-ray-induced tissue damage. We used rodent testes as a model to investigate the role of dose-rate in SR X-ray-induced tissue damage. One day after SR X-ray irradiation, we determined the effects of the irradiation of the same dosage at two different dose-rates, 0.11 Gy/s and 1.1 Gy/s, on TUNEL signals, caspase-3 activation and DNA double-strand breaks (DSBs) of the testes. Compared to those produced by the irradiation at 0.11 Gy/s, irradiation at 1.1 Gy/s produced higher levels of DSBs, TUNEL signals, and caspase-3 activation in the testes. Our study has provided the first evidence suggesting that dose-rate could be a significant factor in SR X-ray-induced tissue damage, which may establish a valuable base for utilizing this factor to manipulate the tissue damage in SR X-ray-based medical applications. PMID:28078052

Probing multi-scale mechanical damage in connective tissues using X-ray diffraction.

PubMed

Bianchi, Fabio; Hofmann, Felix; Smith, Andrew J; Thompson, Mark S

2016-11-01

The accumulation of microstructural collagen damage following repetitive loading is linked to painful and debilitating tendon injuries. As a hierarchical, semi-crystalline material, collagen mechanics can be studied using X-ray diffraction. The aim of the study was to describe multi-structural changes in tendon collagen following controlled plastic damage (5% permanent strain). We used small angle X-ray scattering (SAXS) to interrogate the spacing of collagen molecules within a fibril, and wide angle X-ray scattering (WAXS) to measure molecular strains under macroscopic loading. Simultaneous recordings of SAXS and WAXS patterns, together with whole-tissue strain in physiologically hydrated rat-tail tendons were made during increments of in situ tensile loading. Results showed that while tissue level modulus was unchanged, fibril modulus decreased significantly, and molecular modulus significantly increased. Further, analysis of higher order SAXS peaks suggested structural changes in the gap and overlap regions, possibly localising the damage to molecular cross-links. Our results provide new insight into the fundamental damage processes at work in collagenous tissues and point to new directions for their mitigation and repair. This article reports the first in situ loading synchrotron studies on mechanical damage in collagenous tissues. We provide new insight into the nano- and micro-structural mechanisms of damage processes. Pre-damaged tendons showed differential alteration of moduli at macro, micro and nano-scales as measured using X-ray scattering techniques. Detailed analysis of higher order diffraction peaks suggested damage is localised to molecular cross-links. The results are consistent with previous X-ray scattering studies of tendons and also with recent thermal stability studies on damaged material. Detailed understanding of damage mechanisms is essential in the development of new therapies promoting tissue repair. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Spatiotemporal modeling of laser tissue soldering using photothermal nanocomposites.

PubMed

Mushaben, Madaline; Urie, Russell; Flake, Tanner; Jaffe, Michael; Rege, Kaushal; Heys, Jeffrey

2018-02-01

Laser tissue soldering using photothermal solders is a technology that facilitates rapid sealing using heat-induced changes in the tissue and the solder material. The solder material is made of gold nanorods embedded in a protein matrix patch that can be placed over the tissue rupture site and heated with a laser. Although laser tissue soldering is an attractive approach for surgical repair, potential photothermal damage can limit the success of this approach. Development of predictive mathematical models of photothermal effects including cell death, can lead to more efficient approaches in laser-based tissue repair. We describe an experimental and modeling investigation into photothermal solder patches for sealing porcine and mouse cadaver intestine sections using near-infrared laser irradiation. Spatiotemporal changes in temperature were determined at the surface as well as various depths below the patch. A mathematical model, based on the finite element method, predicts the spatiotemporal temperature distribution in the patch and surrounding tissue, as well as concomitant cell death in the tissue is described. For both the porcine and mouse intestine systems, the model predicts temperatures that are quantitatively similar to the experimental measurements with the model predictions of temperature increase often being within a just a few degrees of experimental measurements. This mathematical model can be employed to identify optimal conditions for minimizing healthy cell death while still achieving a strong seal of the ruptured tissue using laser soldering. Lasers Surg. Med. 50:143-152, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Blood-brain barrier disruption induced by diagnostic ultrasound combined with microbubbles in mice

PubMed Central

Liu, Jinfeng; Zhang, Li; Wang, Jing; Yang, Yali; Lv, Qing; Xie, Mingxing

2018-01-01

Objective To investigate the effects of the microbubble (MB) dose, mechanism index (MI) and sonication duration on blood-brain barrier (BBB) disruption induced by diagnostic ultrasound combined with MBs as well as to investigate the potential molecular mechanism. Results The extent of BBB disruption increased with MB dose, MI and sonication duration. A relatively larger extent of BBB disruption associated with minimal tissue damage was achieved by an appropriate MB dose and ultrasound exposure parameters with diagnostic ultrasound. Decreased expression of ZO-1, occludin and claudin-5 were correlated with disruption of the BBB, as confirmed by paracellular passage of the tracer lanthanum nitrate into the brain parenchyma after BBB disruption. Conclusions These findings indicated that this technique is a promising tool for promoting brain delivery of diagnostic and therapeutic agents in the diagnosis and treatment of brain diseases. Methods The extent of BBB disruption was qualitatively assessed by Evans blue (EB) staining and quantitatively analyzed by an EB extravasation measurement. A histological examination was performed to evaluate tissue damage. Expression of tight junction (TJ) related proteins ZO-1, occludin and claudin-5 was determined by western blotting analysis and immunohistofluorescence. Transmission electron microscopy was performed to observe ultrastructure changes of TJs after BBB disruption. PMID:29435150

Tumor necrosis factor-alpha induced enhancement of cryosurgery

NASA Astrophysics Data System (ADS)

Goel, Raghav; Paciotti, Guilio F.; Bischof, John C.

2008-02-01

Local recurrence of cancer after cryosurgery is related to the inability to monitor and predict destruction of cancer (temperatures > -40°C) within an iceball. We previously reported that a cytokine adjuvant TNF-α could be used to achieve complete cancer destruction at the periphery of an iceball (0 to -40°C). This study is a further development of that work in which cryosurgery was performed using cryoprobes operating at temperatures > -40°C. LNCaP Pro 5 tumor grown in a dorsal skin fold chamber (DSFC) was frozen at -6°C after TNF-α incubation for 4 or 24 hours. Tumors grown in the hind limb were frozen with a probe tip temperature of -40°C, 4 or 24 hours after systemic injection with TNF-α. Both cryosurgery alone or TNF-α treatment alone caused only a minimal damage to the tumor tissue at the conditions used in the study. The combination of TNF-α and cryosurgery produced a significant damage to the tumor tissue in both the DSFC and the hind limb model system. This augmentation in cryoinjury was found to be time-dependent with 4-hour time period between the two treatments being more effective than 24-hour. These results suggests the possibility of cryotreatment at temperatures > -40°C with the administration of TNF-α.

Neonatal bone marrow transplantation prevents bone pathology in a mouse model of mucopolysaccharidosis type I.

PubMed

Pievani, Alice; Azario, Isabella; Antolini, Laura; Shimada, Tsutomu; Patel, Pravin; Remoli, Cristina; Rambaldi, Benedetta; Valsecchi, Maria Grazia; Riminucci, Mara; Biondi, Andrea; Tomatsu, Shunji; Serafini, Marta

2015-03-05

Neonatal bone marrow transplantation (BMT) could offer a novel therapeutic opportunity for genetic disorders by providing sustainable levels of the missing protein at birth, thus preventing tissue damage. We tested this concept in mucopolysaccharidosis type I (MPS IH; Hurler syndrome), a lysosomal storage disorder caused by deficiency of α-l-iduronidase. MPS IH is characterized by a broad spectrum of clinical manifestations, including severe progressive skeletal abnormalities. Although BMT increases the life span of patients with MPS IH, musculoskeletal manifestations are only minimally responsive if the timing of BMT delays, suggesting already irreversible bone damage. In this study, we tested the hypothesis that transplanting normal BM into newborn MPS I mice soon after birth can prevent skeletal dysplasia. We observed that neonatal BMT was effective at restoring α-l-iduronidase activity and clearing elevated glycosaminoglycans in blood and multiple organs. At 37 weeks of age, we observed an almost complete normalization of all bone tissue parameters, using radiographic, microcomputed tomography, biochemical, and histological analyses. Overall, the magnitude of improvements correlated with the extent of hematopoietic engraftment. We conclude that BMT at a very early stage in life markedly reduces signs and symptoms of MPS I before they appear. © 2015 by The American Society of Hematology.

Enhancement of radiotherapy by ceria nanoparticles modified with neogambogic acid in breast cancer cells

PubMed Central

Chen, Feng; Zhang, Xiao Hong; Hu, Xiao Dan; Zhang, Wei; Lou, Zhi Chao; Xie, Li Hua; Liu, Pei Dang; Zhang, Hai Qian

2015-01-01

Radiotherapy is one of the main strategies for cancer treatment but has significant challenges, such as cancer cell resistance and radiation damage to normal tissue. Radiosensitizers that selectively increase the susceptibility of cancer cells to radiation can enhance the effectiveness of radiotherapy. We report here the development of a novel radiosensitizer consisting of monodispersed ceria nanoparticles (CNPs) covered with the anticancer drug neogambogic acid (NGA-CNPs). These were used in conjunction with radiation in MCF-7 breast cancer cells, and the efficacy and mechanisms of action of this combined treatment approach were evaluated. NGA-CNPs potentiated the toxic effects of radiation, leading to a higher rate of cell death than either treatment used alone and inducing the activation of autophagy and cell cycle arrest at the G2/M phase, while pretreatment with NGA or CNPs did not improve the rate of radiation-induced cancer cells death. However, NGA-CNPs decreased both endogenous and radiation-induced reactive oxygen species formation, unlike other nanomaterials. These results suggest that the adjunctive use of NGA-CNPs can increase the effectiveness of radiotherapy in breast cancer treatment by lowering the radiation doses required to kill cancer cells and thereby minimizing collateral damage to healthy adjacent tissue. PMID:26316742

Heterometallic Ru-Pt metallacycle for two-photon photodynamic therapy.

PubMed

Zhou, Zhixuan; Liu, Jiangping; Rees, Thomas W; Wang, Heng; Li, Xiaopeng; Chao, Hui; Stang, Peter J

2018-05-29

As an effective and noninvasive treatment of various diseases, photodynamic therapy (PTD) relies on the combination of light, a photosensitizer, and oxygen to generate cytotoxic reactive oxygen species that can damage malignant tissue. Much attention has been paid to covalent modifications of the photosensitizers to improve their photophysical properties and to optimize the pathway of the photosensitizers interacting with cells within the target tissue. Herein we report the design and synthesis of a supramolecular heterometallic Ru-Pt metallacycle via coordination-driven self-assembly. While inheriting the excellent photostability and two-photon absorption characteristics of the Ru(II) polypyridyl precursor, the metallacycle also exhibits red-shifted luminescence to the near-infrared region, a larger two-photon absorption cross-section, and higher singlet oxygen generation efficiency, making it an excellent candidate as a photosensitizer for PTD. Cellular studies reveal that the metallacycle selectively accumulates in mitochondria and nuclei upon internalization. As a result, singlet oxygen generated by photoexcitation of the metallacycle can efficiently trigger cell death via the simultaneous damage to mitochondrial function and intranuclear DNA. In vivo studies on tumor-bearing mice show that the metallacycle can efficiently inhibit tumor growth under a low light dose with minimal side effects. The supramolecular approach presented in this work provides a paradigm for the development of PDT agents with high efficacy.

The characterization of neural tissue ablation rate and corresponding heat affected zone of a 2 micron Tm3+ doped fiber laser(Conference Presentation)

NASA Astrophysics Data System (ADS)

Marques, Andrew J.; Jivraj, Jamil; Reyes, Robnier; Ramjist, Joel; Gu, Xijia J.; Yang, Victor X. D.

2017-02-01

Tissue removal using electrocautery is standard practice in neurosurgery since tissue can be cut and cauterized simultaneously. Thermally mediated tissue ablation using lasers can potentially possess the same benefits but with increased precision. However, given the critical nature of the spine, brain, and nerves, the effects of direct photo-thermal interaction on neural tissue needs to be known, yielding not only high precision of tissue removal but also increased control of peripheral heat damage. The proposed use of lasers as a neurosurgical tool requires that a common ground is found between ablation rates and resulting peripheral heat damage. Most surgical laser systems rely on the conversion of light energy into heat resulting in both desirable and undesirable thermal damage to the targeted tissue. Classifying the distribution of thermal energy in neural tissue, and thus characterizing the extent of undesirable thermal damage, can prove to be exceptionally challenging considering its highly inhomogenous composition when compared to other tissues such as muscle and bone. Here we present the characterization of neural tissue ablation rate and heat affected zone of a 1.94 micron thulium doped fiber laser for neural tissue ablation. In-Vivo ablation of porcine cerebral cortex is performed. Ablation volumes are studied in association with laser parameters. Histological samples are taken and examined to characterize the extent of peripheral heat damage.

Nd3+/Yb3+ cascade-sensitized single-band red upconversion emission in active-core/active-shell nanocrystals.

PubMed

Ding, M Y; Hou, J J; Yuan, Y J; Bai, W F; Lu, C H; Xi, J H; Ji, Z G; Chen, D Q

2018-08-24

Lanthanide-doped upconversion nanomaterials (UCNMs) have promoted extensive interest for its biological research and biomedical applications, benefiting from low autofluorescence background, deep light penetration depth, and minimal photo-damage to biological tissues. However, owing to the 980 nm laser-induced overheating issue and the attenuation effect associated with conventional multi-peak emissions, the usage of UCNMs as fluorescent bioprobes is still limited. To address these issues, an effective strategy has been proposed to tune both the excitation and emission peaks of UCNMs into the first biological window (650 ∼ 900 nm), where the light absorption by water and hemoglobin in biological tissues is minimal. Based on the Nd 3+ /Yb 3+ cascade-sensitized upconversion process and efficient exchange-energy transfer between Mn 2+ and Er 3+ in conjunction with the active-core@active-shell nanostructured design, we have developed a new class of upconversion nanoparticles (UCNPs) that exhibit strong single-band red emission upon excitation of an 808 nm near-infrared laser. Hopefully, the well-designed KMnF 3 :Yb/Er/Nd@ KMnF 3 :Yb/Nd core-shell nanocrystals will be considered a promising alternative to conventionally used UCNPs for biolabeling applications without the concern of the overheating issue and the attenuation constraints.

Minimizing metastatic risk in radiotherapy fractionation schedules

NASA Astrophysics Data System (ADS)

Badri, Hamidreza; Ramakrishnan, Jagdish; Leder, Kevin

2015-11-01

Metastasis is the process by which cells from a primary tumor disperse and form new tumors at distant anatomical locations. The treatment and prevention of metastatic cancer remains an extremely challenging problem. This work introduces a novel biologically motivated objective function to the radiation optimization community that takes into account metastatic risk instead of the status of the primary tumor. In this work, we consider the problem of developing fractionated irradiation schedules that minimize production of metastatic cancer cells while keeping normal tissue damage below an acceptable level. A dynamic programming framework is utilized to determine the optimal fractionation scheme. We evaluated our approach on a breast cancer case using the heart and the lung as organs-at-risk (OAR). For small tumor α /β values, hypo-fractionated schedules were optimal, which is consistent with standard models. However, for relatively larger α /β values, we found the type of schedule depended on various parameters such as the time when metastatic risk was evaluated, the α /β values of the OARs, and the normal tissue sparing factors. Interestingly, in contrast to standard models, hypo-fractionated and semi-hypo-fractionated schedules (large initial doses with doses tapering off with time) were suggested even with large tumor α/β values. Numerical results indicate the potential for significant reduction in metastatic risk.

Pathogenic traits of Salmonella Montevideo in experimental infections in vivo and in vitro

PubMed Central

Lalsiamthara, Jonathan; Lee, John Hwa

2017-01-01

Salmonella serovar Montevideo (SM) is frequently associated with human Salmonella infections and causes gastrointestinal disease, cases are common particularly among individuals who come in close contact with live poultry or poultry meat products. To characterize SM disease in chickens, the pathogenic traits and tissue predilections of the disease were investigated. Dissemination of fluorescent-tagged SM (JOL1575GFP) was monitored after oral and intramuscular mock infections of specific-pathogen-free chickens. The spleen was predominantly affected by intramuscular infection while the cecum, spleen, and minimally liver were affected by oral infection. No conspicuous illness was observed in infected birds, and histopathological examination showed minimal damage of the intestinal epithelium and splenic parenchyma though SM was readily isolated from these tissues. Levels of SM internalization by primary chicken peritoneal macrophages were similar to that of Salmonella Typhimurium. SM was more sensitive to chicken than rabbit serum complement killing. Internal egg contamination of SM mock infected layers also occurred at trace levels and lasted for a week after inoculation. This study also confirmed that SM infection in chickens is sub-clinical and asymptomatic, which suggests that latent asymptomatic carriers may excrete a large number of bacteria and transmit the pathogen by contaminating water or food sources. PMID:28387311

Tissue engineering strategies applied in the regeneration of the human intervertebral disk.

PubMed

Silva-Correia, Joana; Correia, Sandra I; Oliveira, Joaquim M; Reis, Rui L

2013-12-01

Low back pain (LBP) is one of the most common painful conditions that lead to work absenteeism, medical visits, and hospitalization. The majority of cases showing signs of LBP are due to age-related degenerative changes in the intervertebral disk (IVD), which are, in fact, associated with multiple spine pathologies. Traditional and more conservative procedures/clinical approaches only treat the symptoms of disease and not the underlying pathology, thus limiting their long-term efficiency. In the last few years, research and development of new approaches aiming to substitute the nucleus pulposus and annulus fibrosus tissue and stimulate its regeneration has been conducted. Regeneration of the damaged IVD using tissue engineering strategies appears particularly promising in pre-clinical studies. Meanwhile, surgical techniques must be adapted to this new approach in order to be as minimally invasive as possible, reducing recovering time and side effects associated to traditional surgeries. In this review, the current knowledge on IVD, its associated pathologies and current surgical procedures are summarized. Furthermore, it also provides a succinct and up-to-date overview on regenerative medicine research, especially on the newest tissue engineering strategies for IVD regeneration. © 2013.

Evaluation of DNA damage induced by gamma radiation in gill and muscle tissues of Cyprinus carpio and their relative sensitivity.

PubMed

M K, Praveen Kumar; Shyama, Soorambail K; D'Costa, Avelyno; Kadam, Samit B; Sonaye, Bhagatsingh Harisingh; Chaubey, Ramesh Chandra

2017-10-01

The effect of radiation on the aquatic environment is of major concern in recent years. Limited data is available on the genotoxicity of gamma radiation on different tissues of aquatic organisms. Hence, the present investigation was carried out to study the DNA damage induced by gamma radiation in the gill and muscle tissues and their relative sensitivity using the comet assay in the freshwater teleost fish, common carp (Cyprinus carpio). The comet assay was optimized and validated in common carp using cyclophosphamide (CP), a reference genotoxic agent. The fish were exposed (acute) to various doses of gamma radiation (2, 4, 6, 8 and 10Gy) and samplings (gill and muscle tissue) were done at regular intervals (24, 48 and 72h) to assess the DNA damage. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA for all doses of gamma radiation in both tissues. We also observed a dose-related increase and a time-dependent decrease of DNA damage. In comparison, DNA damage showed different sensitivity among the tissues at different doses. This shows that a particular dose may have different effects on different tissues which could be due to physiological factors of the particular tissue. Our study also suggests that the gills and muscle of fish are sensitive and reliable tissues for evaluating the genotoxic effects of reference and environmental agents, using the comet assay. Copyright © 2017. Published by Elsevier Inc.

Infrared laser sealing of porcine vascular tissues using a 1,470 nm diode laser: Preliminary in vivo studies.

PubMed

Cilip, Christopher M; Kerr, Duane; Latimer, Cassandra A; Rosenbury, Sarah B; Giglio, Nicholas C; Hutchens, Thomas C; Nau, William H; Fried, Nathaniel M

2017-04-01

Infrared (IR) lasers are being explored as an alternative to radiofrequency (RF) and ultrasonic (US) devices for rapid hemostasis with minimal collateral zones of thermal damage and tissue necrosis. Previously, a 1,470 nm IR laser sealed and cut ex vivo porcine renal arteries of 1-8 mm diameter in 2 seconds, yielding burst pressures greater than 1,200 mmHg and thermal coagulation zones less than 3 mm. This preliminary study describes in vivo testing of a handheld laser probe in a porcine model. A handheld prototype with vessel/tissue clasping mechanism was tested on 73 blood vessels less than 6 mm diameter using 1,470 nm laser power of 35 W for 1-5 seconds. Device power settings, irradiation time, tissue type, vessel diameter, and histology sample number were recorded for each procedure. The probe was evaluated for hemostasis after sealing isolated and bundled arteriole/venous (A/V) vasculature of porcine abdomen and hind leg. Sealed vessel samples were collected for histological analysis of lateral thermal damage. Hemostasis was achieved in 57 of 73 seals (78%). The probe consistently sealed vasculature in small bowel mesentery, mesometrium, and gastrosplenic and epiploic regions. Seal performance was less consistent on hind leg vasculature including saphenous arteries/bundles and femoral and iliac arteries. Collagen denaturation averaged 1.6 ± 0.9 mm in eight samples excised for histologic examination. A handheld laser probe sealed porcine vessels, in vivo. Further probe development and laser parameter optimization is necessary before infrared lasers may be evaluated as an alternative to RF and US vessel sealing devices. Lasers Surg. Med. 49:366-371, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Safety and effectiveness of a polyvinyl alcohol barrier in reducing risks of vascular tissue damage during anterior spinal revision surgery.

PubMed

Jeffords, Paul; Li, Jinsheng; Panchal, Deepal; Denoziere, Guilhem; Fetterolf, Donald

2012-05-01

This study was conducted as a controlled, prospective investigation to show the safety and efficacy of a polyvinyl alcohol (PVA) device in a sheep model. To evaluate the ability of a permanent PVA hydrogel barrier to reduce the risk of potential vessel damage during anterior vertebral revision surgery, to provide a nonadhesive barrier at the surgical site, and to create a surgical revision plane of dissection. The development of scar tissue and adhesions presents a significant postoperative problem in spine surgery, where adhesion involvement of overlying structures can cause pain, neurovascular complications, and present a difficult surgical environment during revisions. The devices were implanted onto the ventral surface of exposed lumbar intervertebral discs using an anterolateral approach. One disc separated from the study site was also exposed to serve as a control. Three sheep each were then evaluated with an explant procedure at 30 and 90 days. Extensive sampling was undertaken to evaluate gross anatomic, micropathologic, and biochemical environments and properties of the device. The structural properties and appearance of the device remained intact at both 30 and 90 days. The material remained flexible, hydrophilic, and soft, without visible resorption or decomposition. The material was well tolerated by the animal, with minimal histologic signs of inflammation or rejection. Tissue planes were easily able to be localized by the surgeon attempting to locate the prior surgical site at the time of resection. The PVA vessel shield effectively protected the structures overlying the sheep spine during revision, providing a clear dissection plane for resection at repeat surgery. The overlying structures separated from the previous surgical site with no adhesion, and allowed safe separation of adjacent tissues without the use of sharp dissection.

Development of a systems-based in situ multiplex biomarker screening approach for the assessment of immunopathology and neural tissue plasticity in male rats after traumatic brain injury.

PubMed

Bogoslovsky, Tanya; Bernstock, Joshua D; Bull, Greg; Gouty, Shawn; Cox, Brian M; Hallenbeck, John M; Maric, Dragan

2018-04-01

Traumatic brain injuries (TBIs) pose a massive burden of disease and continue to be a leading cause of morbidity and mortality throughout the world. A major obstacle in developing effective treatments is the lack of comprehensive understanding of the underlying mechanisms that mediate tissue damage and recovery after TBI. As such, our work aims to highlight the development of a novel experimental platform capable of fully characterizing the underlying pathobiology that unfolds after TBI. This platform encompasses an empirically optimized multiplex immunohistochemistry staining and imaging system customized to screen for a myriad of biomarkers required to comprehensively evaluate the extent of neuroinflammation, neural tissue damage, and repair in response to TBI. Herein, we demonstrate that our multiplex biomarker screening platform is capable of evaluating changes in both the topographical location and functional states of resident and infiltrating cell types that play a role in neuropathology after controlled cortical impact injury to the brain in male Sprague-Dawley rats. Our results demonstrate that our multiplex biomarker screening platform lays the groundwork for the comprehensive characterization of changes that occur within the brain after TBI. Such work may ultimately lead to the understanding of the governing pathobiology of TBI, thereby fostering the development of novel therapeutic interventions tailored to produce optimal tissue protection, repair, and/or regeneration with minimal side effects, and may ultimately find utility in a wide variety of other neurological injuries, diseases, and disorders that share components of TBI pathobiology. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Pediatric Tubular Pulmonary Heart Valve from Decellularized Engineered Tissue Tubes

PubMed Central

Reimer, Jay M.; Syedain, Zeeshan H.; Haynie, Bee H.T.; Tranquillo, Robert T.

2015-01-01

Pediatric patients account for a small portion of the heart valve replacements performed, but a pediatric pulmonary valve replacement with growth potential remains an unmet clinical need. Herein we report the first tubular heart valve made from two decellularized, engineered tissue tubes attached with absorbable sutures, which can meet this need, in principle. Engineered tissue tubes were fabricated by allowing ovine dermal fibroblasts to replace a sacrificial fibrin gel with an aligned, cell-produced collagenous matrix, which was subsequently decellularized. Previously, these engineered tubes became extensively recellularized following implantation into the sheep femoral artery. Thus, a tubular valve made from these tubes may be amenable to recellularization and, ideally, somatic growth. The suture line pattern generated three equi-spaced “leaflets” in the inner tube, which collapsed inward when exposed to back pressure, per tubular valve design. Valve testing was performed in a pulse duplicator system equipped with a secondary flow loop to allow for root distention. All tissue-engineered valves exhibited full leaflet opening and closing, minimal regurgitation (< 5%), and low systolic pressure gradients (< 2.5 mmHg) under pulmonary conditions. Valve performance was maintained under various trans-root pressure gradients and no tissue damage was evident after 2 million cycles of fatigue testing. PMID:26036175

Multi-class biological tissue classification based on a multi-classifier: Preliminary study of an automatic output power control for ultrasonic surgical units.

PubMed

Youn, Su Hyun; Sim, Taeyong; Choi, Ahnryul; Song, Jinsung; Shin, Ki Young; Lee, Il Kwon; Heo, Hyun Mu; Lee, Daeweon; Mun, Joung Hwan

2015-06-01

Ultrasonic surgical units (USUs) have the advantage of minimizing tissue damage during surgeries that require tissue dissection by reducing problems such as coagulation and unwanted carbonization, but the disadvantage of requiring manual adjustment of power output according to the target tissue. In order to overcome this limitation, it is necessary to determine the properties of in vivo tissues automatically. We propose a multi-classifier that can accurately classify tissues based on the unique impedance of each tissue. For this purpose, a multi-classifier was built based on single classifiers with high classification rates, and the classification accuracy of the proposed model was compared with that of single classifiers for various electrode types (Type-I: 6 mm invasive; Type-II: 3 mm invasive; Type-III: surface). The sensitivity and positive predictive value (PPV) of the multi-classifier by cross checks were determined. According to the 10-fold cross validation results, the classification accuracy of the proposed model was significantly higher (p<0.05 or <0.01) than that of existing single classifiers for all electrode types. In particular, the classification accuracy of the proposed model was highest when the 3mm invasive electrode (Type-II) was used (sensitivity=97.33-100.00%; PPV=96.71-100.00%). The results of this study are an important contribution to achieving automatic optimal output power adjustment of USUs according to the properties of individual tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

Magnetic resonance imaging characteristics of nonthermal irreversible electroporation in vegetable tissue.

PubMed

Hjouj, Mohammad; Rubinsky, Boris

2010-07-01

We introduce and characterize the use of MRI for studying nonthermal irreversible electroporation (NTIRE) in a vegetative tissue model. NTIRE is a new minimally invasive surgical technique for tissue ablation in which microsecond, high electric-field pulses form nanoscale defects in the cell membrane that lead to cell death. Clinical NTIRE sequences were applied to a potato tuber tissue model. The potato is used for NTIRE studies because cell damage is readily visible with optical means through a natural oxidation process of released intracellular enzymes (polyphenol oxidase) and the formation of brown-black melanins. MRI sequences of the treated area were taken at various times before and after NTIRE and compared with photographic images. A comparison was made between T1W, T2W, FLAIR and STIR MRIs of NTIRE and photographic images. Some MRI sequences show changes in areas treated by irreversible electroporation. T1W and FLAIR produce brighter images of the treated areas. In contrast, the signal was lost from the treated area when a suppression technique, STIR, was used. There was similarity between optical photographic images of the treated tissue and MRIs of the same areas. This is the first study to characterize MRI of NTIRE in vegetative tissue. We find that NTIRE produces changes in vegetative tissue that can be imaged by certain MRI sequences. This could make MRI an effective tool to study the fundamentals of NTIRE in nonanimal tissue.

Motion compensation for in vivo subcellular optical microscopy.

PubMed

Lucotte, B; Balaban, R S

2014-04-01

In this review, we focus on the impact of tissue motion on attempting to conduct subcellular resolution optical microscopy, in vivo. Our position is that tissue motion is one of the major barriers in conducting these studies along with light induced damage, optical probe loading as well as absorbing and scattering effects on the excitation point spread function and collection of emitted light. Recent developments in the speed of image acquisition have reached the limit, in most cases, where the signal from a subcellular voxel limits the speed and not the scanning rate of the microscope. Different schemes for compensating for tissue displacements due to rigid body and deformation are presented from tissue restriction, gating, adaptive gating and active tissue tracking. We argue that methods that minimally impact the natural physiological motion of the tissue are desirable because the major reason to perform in vivo studies is to evaluate normal physiological functions. Towards this goal, active tracking using the optical imaging data itself to monitor tissue displacement and either prospectively or retrospectively correct for the motion without affecting physiological processes is desirable. Critical for this development was the implementation of near real time image processing in conjunction with the control of the microscope imaging parameters. Clearly, the continuing development of methods of motion compensation as well as significant technological solutions to the other barriers to tissue subcellular optical imaging in vivo, including optical aberrations and overall signal-to-noise ratio, will make major contributions to the understanding of cell biology within the body.

Comparative study on laser tissue ablation between PV and HPS lasers

NASA Astrophysics Data System (ADS)

Kang, Hyun Wook; Jebens, David; Mitchell, Gerald; Koullick, Ed

2008-02-01

Laser therapy for obstructive benign prostatic hyperplasia (BPH) has gained broad adoption due to effective tissue removal, immediate hemostasis, and minor complications. The aim of this study is to quantitatively compare ablation characteristics of PV (Photoselective Vaporization) and the newly introduced HPS (High Performance System) 532 nm lasers. Bovine prostatic tissues were ablated in vitro, using a custom-made scanning system. Laser-induced volume produced by two lasers was quantified as a function of applied power, fiber working distance (WD), and treatment speed. Given the same power of 80 W and speed of 4 mm/s, HPS created up to 50 % higher tissue ablation volume than PV did. PV induced a rapid decrease of ablation volume when WD increased from 0.5 mm to 3 mm while HPS yielded almost constant tissue removal up to 3 mm for both 80 W and 120 W. As the treatment speed increased, both lasers reached saturation in tissue ablation volume. Lastly, both PV and HPS lasers exhibited approximately 1 mm thick heat affected zone (HAZ) in this study although HPS created twice deeper ablation channels with a depth of up to 4 mm. Due to a smaller beam size and a higher output power, HPS maximized tissue ablation rate with minimal thermal effects to the adjacent tissue. Furthermore, more collimated beam characteristics provides more spatial flexibility and may even help to decrease the rate of fiber degradation associated with thermal damage from debris reattachment to the tip.

Expression Profile of DNA Damage Signaling Genes in Proton Exposed Mouse Brain

NASA Astrophysics Data System (ADS)

Ramesh, Govindarajan; Wu, Honglu

Exposure of living systems to radiation results in a wide assortment of lesions, the most signif-icant of is damage to genomic DNA which induce several cellular functions such as cell cycle arrest, repair, apoptosis etc. The radiation induced DNA damage investigation is one of the im-portant area in biology, but still the information available regarding the effects of proton is very limited. In this report, we investigated the differential gene expression pattern of DNA damage signaling genes particularly, damaged DNA binding, repair, cell cycle arrest, checkpoints and apoptosis using quantitative real-time RT-PCR array in proton exposed mouse brain tissues. The expression profiles showed significant changes in DNA damage related genes in 2Gy proton exposed mouse brain tissues as compared with control brain tissues. Furthermore, we also show that significantly increased levels of apoptotic related genes, caspase-3 and 8 activities in these cells, suggesting that in addition to differential expression of DNA damage genes, the alteration of apoptosis related genes may also contribute to the radiation induced DNA damage followed by programmed cell death. In summary, our findings suggest that proton exposed brain tissue undergo severe DNA damage which in turn destabilize the chromatin stability.

Supra-threshold epidermis injury from near-infrared laser radiation prior to ablation onset

NASA Astrophysics Data System (ADS)

DeLisi, Michael P.; Peterson, Amanda M.; Lile, Lily A.; Noojin, Gary D.; Shingledecker, Aurora D.; Stolarski, David J.; Zohner, Justin J.; Kumru, Semih S.; Thomas, Robert J.

2017-02-01

With continued advancement of solid-state laser technology, high-energy lasers operating in the near-infrared (NIR) band are being applied in an increasing number of manufacturing techniques and medical treatments. Safety-related investigations of potentially harmful laser interaction with skin are commonplace, consisting of establishing the maximum permissible exposure (MPE) thresholds under various conditions, often utilizing the minimally-visible lesion (MVL) metric as an indication of damage. Likewise, characterization of ablation onset and velocity is of interest for therapeutic and surgical use, and concerns exceptionally high irradiance levels. However, skin injury response between these two exposure ranges is not well understood. This study utilized a 1070-nm Yb-doped, diode-pumped fiber laser to explore the response of excised porcine skin tissue to high-energy exposures within the supra-threshold injury region without inducing ablation. Concurrent high-speed videography was employed to assess the effect on the epidermis, with a dichotomous response determination given for three progressive damage event categories: observable permanent distortion on the surface, formation of an epidermal bubble due to bounded intra-cutaneous water vaporization, and rupture of said bubble during laser exposure. ED50 values were calculated for these categories under various pulse configurations and beam diameters, and logistic regression models predicted injury events with approximately 90% accuracy. The distinction of skin response into categories of increasing degrees of damage expands the current understanding of high-energy laser safety while also underlining the unique biophysical effects during induced water phase change in tissue. These observations could prove useful in augmenting biothermomechanical models of laser exposure in the supra-threshold region.

Reliability of ultra-thin insulation coatings for long-term electrophysiological recordings

NASA Astrophysics Data System (ADS)

Hooker, S. A.

2006-03-01

Improved measurement of neural signals is needed for research into Alzheimer's, Parkinson's, epilepsy, strokes, and spinal cord injuries. At the heart of such instruments are microelectrodes that measure electrical signals in the body. Such electrodes must be small, stable, biocompatible, and robust. However, it is also important that they be easily implanted without causing substantial damage to surrounding tissue. Tissue damage can lead to the generation of immune responses that can interfere with the electrical measurement, preventing long-term recording. Recent advances in microfabrication and nanotechnology afford the opportunity to dramatically reduce the physical dimensions of recording electrodes, thereby minimizing insertion damage. However, one potential cause for concern is the reliability of the insulating coatings, applied to these ultra-fine-diameter wires to precisely control impedance. Such coatings are often polymeric and are applied everywhere but the sharpened tips of the wires, resulting in nominal impedances between 0.5 MOhms and 2.0 MOhms. However, during operation, the polymer degrades, changing the exposed area and the impedance. In this work, ultra-thin ceramic coatings were deposited as an alternative to polymer coatings. Processing conditions were varied to determine the effect of microstructure on measurement stability during two-electrode measurements in a standard buffer solution. Coatings were applied to seven different metals to determine any differences in performance due to the surface characteristics of the underlying wire. Sintering temperature and wire type had significant effects on coating degradation. Dielectric breakdown was also observed at relatively low voltages, indicating that test conditions must be carefully controlled to maximize reliability.

Feasibility of OCT to detect radiation-induced esophageal damage in small animal models (Conference Presentation)

NASA Astrophysics Data System (ADS)

Jelvehgaran, Pouya; Alderliesten, Tanja; Salguero, Javier; Borst, Gerben; Song, Ji-Ying; van Leeuwen, Ton G.; de Boer, Johannes F.; de Bruin, Daniel M.; van Herk, Marcel B.

2016-03-01

Lung cancer survival is poor and radiotherapy patients often suffer serious treatment side effects. The esophagus is particularly sensitive leading to reduced food intake or even fistula formation. Only few direct techniques exist to measure radiation-induced esophageal damage, for which knowledge is needed to improve the balance between risk of tumor recurrence and complications. Optical coherence tomography (OCT) is a minimally-invasive imaging technique that obtains cross-sectional, high-resolution (1-10µm) images and is capable of scanning the esophageal wall up to 2-3mm depth. In this study we investigated the feasibility of OCT to detect esophageal radiation damage in mice. In total 30 mice were included in 4 study groups (1 main and 3 control groups). Mice underwent cone-beam CT imaging for initial setup assessment and dose planning followed by single-fraction dose delivery of 4, 10, 16, and 20Gy on 5mm spots, spaced 10mm apart. Mice were repeatedly imaged using OCT: pre-irradiation and up to 3 months post-irradiation. The control groups received either OCT only, irradiation only, or were sham-operated. We used histopathology as gold standard for radiation-induced damage diagnosis. The study showed edema in both the main and OCT-only groups. Furthermore, radiation-induced damage was primarily found in the highest dose region (distal esophagus). Based on the histopathology reports we were able to identify the radiation-induced damage in the OCT images as a change in tissue scattering related to the type of induced damage. This finding indicates the feasibility and thereby the potentially promising role of OCT in radiation-induced esophageal damage assessment.

Soft, flexible micromanipulators comprising polypyrrole trilayer microactuators

NASA Astrophysics Data System (ADS)

Khaldi, Alexandre; Maziz, Ali; Alici, Gursel; Spinks, Geoffrey M.; Jager, Edwin W. H.

2015-04-01

Within the areas of cell biology, biomedicine and minimal invasive surgery, there is a need for soft, flexible and dextrous biocompatible manipulators for handling biological objects, such as single cells and tissues. Present day technologies are based on simple suction using micropipettes for grasping objects. The micropipettes lack the possibility of accurate force control, nor are they soft and compliant and may thus cause damage to the cells or tissue. Other micromanipulators use conventional electric motors however the further miniaturization of electrical motors and their associated gear boxes and/or push/pull wires has reached its limits. Therefore there is an urgent need for new technologies for micromanipulation of soft biological matter. We are developing soft, flexible micromanipulators such as micro- tweezers for the handling and manipulation of biological species including cells and surgical tools for minimal invasive surgery. Our aim is to produce tools with minimal dimensions of 100 μm to 1 mm in size, which is 1-2 orders of magnitude smaller than existing technology. We present newly developed patterning and microfabrication methods for polymer microactuators as well as the latest results to integrate these microactuators into easy to use manipulation tools. The outcomes of this study contribute to the realisation of low-foot print devices articulated with electroactive polymer actuators for which the physical interface with the power source has been a significant challenge limiting their application. Here, we present a new bottom-up microfabrication process. We show for the first time that such a bottom-up fabricated actuator performs a movement in air. This is a significant step towards widening the application areas of the soft microactuators.

Synchrotron microbeam irradiation induces neutrophil infiltration, thrombocyte attachment and selective vascular damage in vivo.

PubMed

Brönnimann, Daniel; Bouchet, Audrey; Schneider, Christoph; Potez, Marine; Serduc, Raphaël; Bräuer-Krisch, Elke; Graber, Werner; von Gunten, Stephan; Laissue, Jean Albert; Djonov, Valentin

2016-09-19

Our goal was the visualizing the vascular damage and acute inflammatory response to micro- and minibeam irradiation in vivo. Microbeam (MRT) and minibeam radiation therapies (MBRT) are tumor treatment approaches of potential clinical relevance, both consisting of parallel X-ray beams and allowing the delivery of thousands of Grays within tumors. We compared the effects of microbeams (25-100 μm wide) and minibeams (200-800 μm wide) on vasculature, inflammation and surrounding tissue changes during zebrafish caudal fin regeneration in vivo. Microbeam irradiation triggered an acute inflammatory response restricted to the regenerating tissue. Six hours post irradiation (6 hpi), it was infiltrated by neutrophils and fli1a(+) thrombocytes adhered to the cell wall locally in the beam path. The mature tissue was not affected by microbeam irradiation. In contrast, minibeam irradiation efficiently damaged the immature tissue at 6 hpi and damaged both the mature and immature tissue at 48 hpi. We demonstrate that vascular damage, inflammatory processes and cellular toxicity depend on the beam width and the stage of tissue maturation. Minibeam irradiation did not differentiate between mature and immature tissue. In contrast, all irradiation-induced effects of the microbeams were restricted to the rapidly growing immature tissue, indicating that microbeam irradiation could be a promising tumor treatment tool.

Parametric study of irreversible electroporation with different needle electrodes: electrical and thermal analysis.

PubMed

Nickfarjam, Abolfazl; Firoozabadi, S Mohammad P

2014-08-01

Irreversible electroporation (IRE) is a new tumour ablation method used in cancer treatment procedures. In a successful IRE treatment it is crucial to impose minimum thermal damage to the tumour and its surrounding healthy tissue, while subjecting the entire tumour to a strong electric field. Here we present a 3D model of a subcutaneous tumour in a four-layer skin using a geometry-based finite element approach. Four common needle electrode configurations were studied in this paper. The study evaluated six essential factors which are important in the electrical and thermal distributions in tumour and normal tissue. The results revealed that a hexagonal 3 × 3 geometry provides the maximum electrical coverage of the tumour, compared to other electrode configurations. However, in some cases the hexagonal 2 × 2 geometry can ablate the entire tumour with less damage to normal tissue. We found that the deeper insertion of 2- and 4-electrode geometries can lead to more damage to healthy tissue. The results also indicate that the insertion of the electrodes into tumour tissue can increase thermal damage dramatically due to existing large electrical conductivity. These findings suggest that needle electrodes should not be placed within the tumour tissue if the goal is to prevent thermal damage. This method can be used as a trade-off between electric field coverage in tumour tissue and thermal damage to both tumour and normal tissue.

Roles of oxidative stress in synchrotron radiation X-ray-induced testicular damage of rodents

PubMed Central

Ma, Yingxin; Nie, Hui; Sheng, Caibin; Chen, Heyu; Wang, Ban; Liu, Tengyuan; Shao, Jiaxiang; He, Xin; Zhang, Tingting; Zheng, Chaobo; Xia, Weiliang; Ying, Weihai

2012-01-01

Synchrotron radiation (SR) X-ray has characteristic properties such as coherence and high photon flux, which has excellent potential for its applications in medical imaging and cancer treatment. However, there is little information regarding the mechanisms underlying the damaging effects of SR X-ray on biological tissues. Oxidative stress plays an important role in the tissue damage induced by conventional X-ray, while the role of oxidative stress in the tissue injury induced by SR X-ray remains unknown. In this study we used the male gonads of rats as a model to study the roles of oxidative stress in SR X-ray-induced tissue damage. Exposures of the testes to SR X-ray at various radiation doses did not significantly increase the lipid peroxidation of the tissues, assessed at one day after the irradiation. No significant decreases in the levels of GSH or total antioxidation capacity were found in the SR X-ray-irradiated testes. However, the SR X-ray at 40 Gy induced a marked increase in phosphorylated H2AX – a marker of double-strand DNA damage, which was significantly decreased by the antioxidant N-acetyl cysteine (NAC). NAC also attenuated the SR X-ray-induced decreases in the cell layer number of seminiferous tubules. Collectively, our observations have provided the first characterization of SR X-ray-induced oxidative damage of biological tissues: SR X-ray at high doses can induce DNA damage and certain tissue damage during the acute phase of the irradiation, at least partially by generating oxidative stress. However, SR X-ray of various radiation doses did not increase lipid peroxidation. PMID:22837810

Stem Cell Research: A Novel Boulevard towards Improved Bovine Mastitis Management

PubMed Central

Sharma, Neelesh; Jeong, Dong Kee

2013-01-01

The dairy industry is a multi-billion dollar industry catering the nutritional needs of all age groups globally through the supply of milk. Clinical mastitis has a severe impact on udder tissue and is also an animal welfare issue. Moreover, it significantly reduces animal value and milk production. Mammary tissue damage reduces the number and activity of epithelial cells and consequently contributes to decreased milk production. The high incidence, low cure rate of this highly economic and sometimes deadly disease is an alarming for dairy sector as well as policy makers. Bovine mammary epithelial cells (MECs) and their stem cells are very important in milk production and bioengineering. The adult mammary epithelium consists of two main cell types; an inner layer of luminal epithelial cells, which produce the milk during lactation, and an outer layer of myoepithelial cells resting on a basement membrane, which are responsible for pushing the milk through the ductal network to the teat cistern. Inner layer of columner/luminal cells of bovine MECs, is characterized by cytokeratin18, 19 (CK18, CK19) and outer layer such as myoepithelial cells which are characterized by CK14, α-smooth muscle actin (α-SMA) and p63. Much work has been done in mouse and human, on mammary gland stem cell research, particularly in cancer therapy, but stem cell research in bovine is still in its infancy. Such stem/progenitor cell discoveries in human and mouse mammary gland bring some hope for application in bovines. These progenitors may be therapeutically adopted to correct the structural/cytological defects in the bovine udder due to mastitis. In the present review we focused on various kinds of stem/progenitor cells which can have therapeutic utility and their possibilities to use as a potential stem cell therapy in the management of bovine post-mastitis damage in orders to restore milk production. The possibilities of bovine mammary stem cell therapy offers significant potential for regeneration of tissues that can potentially replace/repair diseased and damaged tissue through differentiation into epithelial, myoepithelial and/or cuboidal/columnar cells in the udder with minimal risk of rejection and side effects. PMID:23983615

Stem cell research: a novel boulevard towards improved bovine mastitis management.

PubMed

Sharma, Neelesh; Jeong, Dong Kee

2013-01-01

The dairy industry is a multi-billion dollar industry catering the nutritional needs of all age groups globally through the supply of milk. Clinical mastitis has a severe impact on udder tissue and is also an animal welfare issue. Moreover, it significantly reduces animal value and milk production. Mammary tissue damage reduces the number and activity of epithelial cells and consequently contributes to decreased milk production. The high incidence, low cure rate of this highly economic and sometimes deadly disease is an alarming for dairy sector as well as policy makers. Bovine mammary epithelial cells (MECs) and their stem cells are very important in milk production and bioengineering. The adult mammary epithelium consists of two main cell types; an inner layer of luminal epithelial cells, which produce the milk during lactation, and an outer layer of myoepithelial cells resting on a basement membrane, which are responsible for pushing the milk through the ductal network to the teat cistern. Inner layer of columner/luminal cells of bovine MECs, is characterized by cytokeratin18, 19 (CK18, CK19) and outer layer such as myoepithelial cells which are characterized by CK14, α-smooth muscle actin (α-SMA) and p63. Much work has been done in mouse and human, on mammary gland stem cell research, particularly in cancer therapy, but stem cell research in bovine is still in its infancy. Such stem/progenitor cell discoveries in human and mouse mammary gland bring some hope for application in bovines. These progenitors may be therapeutically adopted to correct the structural/cytological defects in the bovine udder due to mastitis. In the present review we focused on various kinds of stem/progenitor cells which can have therapeutic utility and their possibilities to use as a potential stem cell therapy in the management of bovine post-mastitis damage in orders to restore milk production. The possibilities of bovine mammary stem cell therapy offers significant potential for regeneration of tissues that can potentially replace/repair diseased and damaged tissue through differentiation into epithelial, myoepithelial and/or cuboidal/columnar cells in the udder with minimal risk of rejection and side effects.

Experimental and theoretical investigation of intratumoral nanoparticle distribution to enhance magnetic nanoparticle hyperthermia

NASA Astrophysics Data System (ADS)

Attaluri, Anilchandra

Magnetic nanoparticles have gained prominence in recent years for use in clinical applications such as imaging, drug delivery, and hyperthermia. Magnetic nanoparticle hyperthermia is a minimally invasive and effective approach for confined heating in tumors with little collateral damage. One of the major problems in the field of magnetic nanoparticle hyperthermia is irregular heat distribution in tumors which caused repeatable heat distribution quite impossible. This causes under dosage in tumor area and overheating in normal tissue. In this study, we develop a unified approach to understand magnetic nanoparticle distribution and temperature elevations in gel and tumors. A microCT imaging system is first used to visualize and quantify nanoparticle distribution in both tumors and tissue equivalent phantom gels. The microCT based nanoparticle concentration is related to specific absorption rate (SAR) of the nanoparticles and is confirmed by heat distribution experiments in tissue equivalent phantom gels. An optimal infusion protocol is identified to generate controllable and repeatable nanoparticle distribution in tumors. In vivo animal experiments are performed to measure intratumoral temperature elevations in PC3 xenograft tumors implanted in mice during magnetic nanoparticle hyperthermia. The effect of nanofluid injection parameters on the resulted temperature distribution is studied. It shows that the tumor temperatures can be elevated above 50°C using very small amounts of ferrofluid with a relatively low magnetic field. Slower ferrofluid infusion rates result in smaller nanoparticle distribution volumes in the tumors, however, it gives the much required controllability and repeatability when compared to the higher infusion rates. More nanoparticles occupy a smaller volume in the vicinity of the injection site with slower infusion rates, causing higher temperature elevations in the tumors. Based on the microCT imaging analyses of nanoparticles in tumors, a mass transport model is developed to simulate nanoparticle convection and diffusion in tumors, heat-induced tumor structural changes, as well as nanoparticle re-distribution during nanoparticle hyperthermia procedures. The modeled thermal damage induced nanoparticle redistribution predicts a 20% increase in the radius of the spherical tissue region containing nanoparticles. The developed model has demonstrated the feasibility of enhancing nanoparticle dispersion from injection sites using targeted thermal damage.

Comparison of ferromagnetic induction and bipolar electrosurgery and suction in corticotomies in pig cerebrum.

PubMed

Bowers, Christian A; Burns, Greg; Salzman, Karen; McGill, Lawrence; MacDonald, Joel D

2015-04-01

The effects of newer energy-based surgical dissection and coagulation modalities on cerebral tissue have not been investigated. Several instruments have been developed to address the limitations of traditional electrosurgical instruments in the nervous system. We compared the effects of standard bipolar electrocautery and suction (BPS) with those of a new ferromagnetic induction (FMI) device in corticotomies of pig cerebral tissue as assessed by magnetic resonance imaging (MRI) and histological analysis. Three adult pigs underwent bilateral corticotomies (3 cm long×1 cm deep) using both FMI and BPS. The acute cerebral tissue edema created by each method was measured on coronal volumetric T2-weighted MRI sequences immediately after surgery. A lateral thermal "damage index" was calculated by dividing the width of the visible T2 tissue edema by the measured depth. The radiographic damage indices with each method were compared statistically. Histological analysis of each incision was conducted to compare the extent of tissue damage. MRI showed that the mean radiographic damage index of each corticotomy was significantly lower with the FMI (0.30 ± 0.02 (0.28-0.32)) than with the BPS method (0.54 ± 0.11 (0.42-0.64)) (p = 0.02). Histological analysis suggested a correlation with the radiographic findings as the FMI tissue samples demonstrated less adjacent tissue damage than BPS. FMI appeared to cause less adjacent tissue damage than the BPS method in pig cerebral tissue based on quantitative radiographic and qualitative histological analysis. Future studies are needed to investigate the clinical implications of energy-based surgical dissection on cerebral tissue. Copyright © 2015 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Semiautomatic segmentation of the heart from CT images based on intensity and morphological features

NASA Astrophysics Data System (ADS)

Redwood, Abena B.; Camp, Jon J.; Robb, Richard A.

2005-04-01

The incidence of certain types of cardiac arrhythmias is increasing. Effective, minimally invasive treatment has remained elusive. Pharmacologic treatment has been limited by drug intolerance and recurrence of disease. Catheter based ablation has been moderately successful in treating certain types of cardiac arrhythmias, including typical atrial flutter and fibrillation, but there remains a relatively high rate of recurrence. Additional side effects associated with cardiac ablation procedures include stroke, perivascular lung damage, and skin burns caused by x-ray fluoroscopy. Access to patient specific 3-D cardiac images has potential to significantly improve the process of cardiac ablation by providing the physician with a volume visualization of the heart. This would facilitate more effective guidance of the catheter, increase the accuracy of the ablative process, and eliminate or minimize the damage to surrounding tissue. In this study, a semiautomatic method for faithful cardiac segmentation was investigated using Analyze - a comprehensive processing software package developed at the Biomedical Imaging Resource, Mayo Clinic. This method included use of interactive segmentation based on math morphology and separation of the chambers based on morphological connections. The external surfaces of the hearts were readily segmented, while accurate separation of individual chambers was a challenge. Nonetheless, a skilled operator could manage the task in a few minutes. Useful improvements suggested in this paper would give this method a promising future.

Radiation damage of biomolecules (RADAM) database development: current status

NASA Astrophysics Data System (ADS)

Denifl, S.; Garcia, G.; Huber, B. A.; Marinković, B. P.; Mason, N.; Postler, J.; Rabus, H.; Rixon, G.; Solov'yov, A. V.; Suraud, E.; Yakubovich, A. V.

2013-06-01

Ion beam therapy offers the possibility of excellent dose localization for treatment of malignant tumours, minimizing radiation damage in normal tissue, while maximizing cell killing within the tumour. However, as the underlying dependent physical, chemical and biological processes are too complex to treat them on a purely analytical level, most of our current and future understanding will rely on computer simulations, based on mathematical equations, algorithms and last, but not least, on the available atomic and molecular data. The viability of the simulated output and the success of any computer simulation will be determined by these data, which are treated as the input variables in each computer simulation performed. The radiation research community lacks a complete database for the cross sections of all the different processes involved in ion beam induced damage: ionization and excitation cross sections for ions with liquid water and biological molecules, all the possible electron - medium interactions, dielectric response data, electron attachment to biomolecules etc. In this paper we discuss current progress in the creation of such a database, outline the roadmap of the project and review plans for the exploitation of such a database in future simulations.

Renal denervation by intravascular ultrasound: Preliminary in vivo study

NASA Astrophysics Data System (ADS)

Sinelnikov, Yegor; McClain, Steve; Zou, Yong; Smith, David; Warnking, Reinhard

2012-10-01

Ultrasound denervation has recently become a subject of intense research in connection with the treatment of complex medical conditions including neurological conditions, development of pain management, reproduction of skin sensation, neuropathic pain and spasticity. The objective of this study is to investigate the use of intravascular ultrasound to produce nerve damage in renal sympathetic nerves without significant injury to the renal artery. This technique may potentially be used to treat various medical conditions, such as hypertension. The study was approved by the Institutional Animal Care and Use Committee. Ultrasound was applied to renal nerves of the swine model for histopathological evaluation. Therapeutic ultrasound energy was delivered circumferentially by an intravascular catheter maneuvered into the renal arteries. Fluoroscopic imaging was conducted pre-and post-ultrasound treatment. Animals were recovered and euthanized up to 30 hours post procedure, followed by necropsy and tissue sample collection. Histopathological examination showed evidence of extensive damage to renal nerves, characterized by nuclear pyknosis, hyalinization of stroma and multifocal hemorrhages, with little or no damage to renal arteries. This study demonstrates the feasibility of intravascular ultrasound as a minimally invasive renal denervation technique. Further studies are necessary to evaluate the long-term safety and efficacy of this technique and its related clinical significance.

Pulse-dose radiofrequency treatment in pain management-initial experience.

PubMed

Ojango, Christine; Raguso, Mario; Fiori, Roberto; Masala, Salvatore

2018-05-01

Radiofrequency procedures have been used for treating various chronic pain conditions for decades. These minimally invasive percutaneous treatments employ an alternating electrical current with oscillating radiofrequency wavelengths to eliminate or alter pain signals from the targeted site. The aim of the continuous radiofrequency procedure is to increase the temperature sufficiently to create an irreversible thermal lesion on nerve fibres and thus permanently interrupt pain signals. The pulsed radiofrequency procedure utilises short pulses of radiofrequency current with intervals of longer pauses to avert a temperature increase to the level of permanent tissue damage. The goal of these pulses is to alter the processing of pain signals, but to avoid relevant structural damage to nerve fibres, as seen in the continuous radiofrequency procedure. The pulse-dose radiofrequency procedure is a technical improvement of the pulsed radiofrequency technique in which the delivery mode of the current is adapted. During the pulse-dose radiofrequency procedure thermal damage is avoided. In addition, the amplitude and width of the consecutive pulses are kept the same. The method ensures that each delivered pulse keeps the same characteristics and therefore the dose is similar between patients. The current review outlines the pulse-dose radiofrequency procedure and presents our institution's chronic pain management studies.

Using synchrotron X-ray phase-contrast micro-computed tomography to study tissue damage by laser irradiation.

PubMed

Robinson, Alan M; Stock, Stuart R; Soriano, Carmen; Xiao, Xianghui; Richter, Claus-Peter

2016-11-01

The aim of this study was to determine if X-ray micro-computed tomography could be used to locate and characterize tissue damage caused by laser irradiation and to describe its advantages over classical histology for this application. A surgical CO 2 laser, operated in single pulse mode (100 milliseconds) at different power settings, was used to ablate different types of cadaveric animal tissues. Tissue samples were then harvested and imaged with synchrotron X-ray phase-contrast and micro-computed tomography to generate stacks of virtual sections of the tissues. Subsequently, Fiji (ImageJ) software was used to locate tissue damage, then to quantify volumes of laser ablation cones and thermal coagulation damage from 3D renderings of tissue image stacks. Visual comparisons of tissue structures in X-ray images with those visible by classic light microscopy histology were made. We demonstrated that micro-computed tomography could be used to rapidly identify areas of surgical laser ablation, vacuolization, carbonization, and thermally coagulated tissue. Quantification and comparison of the ablation crater, which represents the volume of ablated tissue, and the thermal coagulation zone volumes were performed faster than we could by classical histology. We demonstrated that these procedures can be performed on fresh hydrated and non-sectioned plastic embedded tissue. We demonstrated that the application of non-destructive micro-computed tomography to the visualization and analysis of laser induced tissue damage without tissue sectioning is possible. This will improve evaluation of new surgical lasers and their corresponding effect on tissues. Lasers Surg. Med. 48:866-877, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Coblation-assisted endonasal endoscopic resection of juvenile nasopharyngeal angiofibroma.

PubMed

Ye, L; Zhou, X; Li, J; Jin, J

2011-09-01

Juvenile nasopharyngeal angiofibroma may be successfully resected using endoscopic techniques. However, the use of coblation technology for such resection has not been described. This study aimed to document cases of Fisch class I juvenile nasopharyngeal angiofibroma with limited nasopharyngeal and nasal cavity extension, which were completely resected using an endoscopic coblation technique. We retrospectively studied 23 patients with juvenile nasopharyngeal angiofibroma who underwent resection with either traditional endoscopic instruments (n = 12) or coblation (n = 11). Intra-operative blood loss and overall operative time were recorded. The mean tumour resection time for coblation and traditional endoscopic instruments was 87 and 136 minutes, respectively (t = 9.962, p < 0.001). Mean intra-operative blood loss was 121 and 420 ml, respectively (t = 28.944, p < 0.001), a significant difference. Both techniques achieved complete tumour resection with minimal damage to adjacent tissues, and no recurrence in any patient. Coblation successfully achieves transnasal endoscopic resection of juvenile nasopharyngeal angiofibroma (Fisch class I), with good surgical margins and minimal blood loss.

Optimal Parameters for Intervertebral Disk Resection Using Aqua-Plasma Beams.

PubMed

Yoon, Sung-Young; Kim, Gon-Ho; Kim, Yushin; Kim, Nack Hwan; Lee, Sangheon; Kawai, Christina; Hong, Youngki

2018-06-14

 A minimally invasive procedure for intervertebral disk resection using plasma beams has been developed. Conventional parameters for the plasma procedure such as voltage and tip speed mainly rely on the surgeon's personal experience, without adequate evidence from experiments. Our objective was to determine the optimal parameters for plasma disk resection.  Rate of ablation was measured at different procedural tip speeds and voltages using porcine nucleus pulposi. The amount of heat formation during experimental conditions was also measured to evaluate the thermal safety of the plasma procedure.  The ablation rate increased at slower procedural speeds and higher voltages. However, for thermal safety, the optimal parameters for plasma procedures with minimal tissue damage were an electrical output of 280 volts root-mean-square (V rms ) and a procedural tip speed of 2.5 mm/s.  Our findings provide useful information for an effective and safe plasma procedure for disk resection in a clinical setting. Georg Thieme Verlag KG Stuttgart · New York.

Submucosal injection of normal saline may prevent tissue damage from argon plasma coagulation: an experimental study using resected porcine esophagus, stomach, and colon.

PubMed

Fujishiro, Mitsuhiro; Yahagi, Naohisa; Nakamura, Masanori; Kakushima, Naomi; Kodashima, Shinya; Ono, Satoshi; Kobayashi, Katsuya; Hashimoto, Takuhei; Yamamichi, Nobutake; Tateishi, Ayako; Shimizu, Yasuhito; Oka, Masashi; Ichinose, Masao; Omata, Masao

2006-10-01

Argon plasma coagulation (APC) is considered to be a safe thermocoagulation technique, but some reports show perforation and deformity during and after APC. In this study, we investigated the usefulness of prior submucosal injection for APC. APC over the mucosa was performed on fresh resected porcine esophagus, stomach, and colon with prior submucosal injection of normal saline (injection group) and without it (control group). The depth of tissue damage increased linearly with pulse duration up to the shallower submucosal layer in both groups. After that, tissue damage in the injection group remained confined to the shallower submucosal layer under any condition, whereas that in the control group continued to extend. The tissue damages of the injection groups were significantly (P<0.05) shallower than those of the control groups that reached the deeper submucosal layer in all the organs. Submucosal injection of normal saline before the application of APC may limit tissue damage and prevent perforation and deformity.

Biophysical and medical safety basis of laser emission

NASA Astrophysics Data System (ADS)

Paltsev, Yu.; Levina, A.

1996-01-01

Laser equipment may inflict serious losses to human health if safety norms established by relevant standards and other documentation are not properly observed. It is explained by physical properties of laser emission (LE) which differs from general light sources by quantitative behavior of such parameters as the degrees of coherence, monochromaticity, brightness, polarization. Thus, biological effects due to laser emission, as a rule, are more expressed comparing with other types of emission from other spontaneous light sources. LE effects biological tissues through the density of energy flow and impulse duration. It is common knowledge nowadays that LE biological action is assessed by two criteria: physical parameters and absorptive properties of tissues exposed to rays. LE causes the greatest danger to the eyes due to their specific structure. The next target organ vulnerable to LE is skin. Pathological changes of skin depend on the LE power, time of exposure, wave length, and the extent of skin pigmentation. Along with different kinds of damage directly in the tissues exposed to rays, LE may cause changes in organs and body systems subject to indirect exposure. It is important that these changes may develop due to low intensity levels of LE that do not cause local damage. National and international standards on LE safety are based on maximum allowable levels (MAL) of exposure. It has been generally accepted that the main MAL criterion is LE threshold minimal exposure which causes damage to retina, eyes, and skin. As distinct from foreign safety standards, hygienic norms and regulations are in force in the Russian Federation where additional co-efficients along with standard generally accepted MAL values have been introduced for the persons who are subject to occupational regular exposure to lasers. This approach has been chosen after the results of follow-up and health studies of these occupational contingents have been analyzed, and experiments on laboratory animals assessed.

Pain management in burn injury.

PubMed

Montgomery, Robert K

2004-03-01

Traumatic bum injuries and the associated treatments are a tremendous pain management challenge. The degree of tissue damage in severe burns can initiate physiologic changes in nociceptive pathways that place the patient at risk for undertreatment. The use of analgesic guidelines that address both background and procedural pain and associated anxiety can provide a rational and consistent approach to treatment. The key to successful treatment is the continuous and accurate assessment of the patient's pain and the response to therapy. Medications, especially opioids, should be regularly evaluated and adjusted to achieve maximum effect and minimal side effect.Nursing's role is perhaps the most important in the essential focused surveillance of bum pain and it's successful treatment.

Postoperative morbidity and histopathologic characteristics of tonsillar tissue following coblation tonsillectomy in children: a prospective randomized single-blind study.

PubMed

Roje, Zeljka; Racić, Goran; Dogas, Zoran; Pisac, Valdi Pesutić; Timms, Michael

2009-03-01

The aim of this prospective randomized single blind study was to determine the depth of thermal damage to tonsillar tissue due to coblation, and to compare it with thermal damage to tonsillar tissue following conventional tonsillectomy; to correlate the depth of thermal damage to tonsillar tissue with the parameters of postoperative morbidity, to compare intraoperative blood loss, postoperative pain severity, time to resuming normal physical activity, and incidence of postoperative bleeding between two groups of tonsillectomized children aged up to 16 years. 72 children aged 3-16 years scheduled for tonsillectomy randomly assigned into two groups submitted either to conventional tonsillectomy with bipolar diathermy coagulation or to coblation tonsillectomy, with a 14-day follow up. Statistically significant differences were observed in the depth of thermal damage to tonsillar tissue (p < 0.001), intraoperative blood loss (p < 0.004), in postoperative pain severity (p < 0.05) and in time to resuming normal physical activity between the two groups (p < 0.001). There was no case of reactionary or secondary bleeding in either group. In this paper for the first time we have correlated postoperative morbidity and thermal tissue damage: less thermal damage is associated with less postoperative morbidity.

A self-harm series and its relationship with childhood adversity among adolescents in mainland China: a cross-sectional study.

PubMed

Han, Azhu; Wang, Gengfu; Xu, Geng; Su, Puyu

2018-02-01

Self-harm (SH) is an emerging problem among Chinese adolescents. The present study aimed to measure the prevalence of SH behaviours and to explore the relationship between childhood adversity and different SH subtypes among Chinese adolescents. A total of 5726 middle school students were randomly selected in three cities of Anhui province, China, using a stratified cluster sampling method. SH was categorized into five subtypes (highly lethal self-harm, less lethal self-harm with visible tissue damage, self-harm without visible tissue damage, self-harmful behaviours with latency damage and psychological self-harm). Multivariate logistic regression was used to explore the relationships between childhood adversity and different subtypes of adolescent SH. The prevalence rates of highly lethal self-harm, less lethal self-harm with visible tissue damage, self-harm without visible tissue damage, self-harmful behaviours with latency damage and psychological self-harm were 6.1, 20.4, 32.0, 20.0 and 23.0%, respectively. Childhood sexual abuse and physical peer victimization were associated with each SH subtype with adjusted odds ratios (AORs) ranging from 1.23 to 1.76. Highly lethal self-harm was associated with childhood physical peer victimization, sexual abuse, emotional abuse, and emotional neglect. The less lethal SH subtypes (i.e., less lethal self-harm with visible tissue damage, self-harm without visible tissue damage, self-harmful behaviours with latency damage and psychological self-harm) were associated with childhood peer victimization, family life stress event scores and childhood sexual abuse. A high prevalence of SH exists among Chinese adolescents. The association of childhood adversity with SH merits serious attention in both future research and preventive interventions.

Time-dependent radiation dose estimations during interplanetary space flights

NASA Astrophysics Data System (ADS)

Dobynde, M. I.; Shprits, Y.; Drozdov, A.

2015-12-01

Time-dependent radiation dose estimations during interplanetary space flights 1,2Dobynde M.I., 2,3Drozdov A.Y., 2,4Shprits Y.Y.1Skolkovo institute of science and technology, Moscow, Russia 2University of California Los Angeles, Los Angeles, USA 3Lomonosov Moscow State University Skobeltsyn Institute of Nuclear Physics, Moscow, Russia4Massachusetts Institute of Technology, Cambridge, USASpace radiation is the main restriction for long-term interplanetary space missions. It induces degradation of external components and propagates inside providing damage to internal environment. Space radiation particles and induced secondary particle showers can lead to variety of damage to astronauts in short- and long- term perspective. Contribution of two main sources of space radiation- Sun and out-of-heliosphere space varies in time in opposite phase due to the solar activity state. Currently the only habituated mission is the international interplanetary station that flights on the low Earth orbit. Besides station shell astronauts are protected with the Earth magnetosphere- a natural shield that prevents significant damage for all humanity. Current progress in space exploration tends to lead humanity out of magnetosphere bounds. With the current study we make estimations of spacecraft parameters and astronauts damage for long-term interplanetary flights. Applying time dependent model of GCR spectra and data on SEP spectra we show the time dependence of the radiation in a human phantom inside the shielding capsule. We pay attention to the shielding capsule design, looking for an optimal geometry parameters and materials. Different types of particles affect differently on the human providing more or less harm to the tissues. Incident particles provide a large amount of secondary particles while propagating through the shielding capsule. We make an attempt to find an optimal combination of shielding capsule parameters, namely material and thickness, that will effectively decrease the incident particle energy, at the same time minimizing flow of secondary induced particles and minimizing most harmful particle types flows.

A potential role for endogenous proteins as sacrificial sunscreens and antioxidants in human tissues.

PubMed

Hibbert, Sarah A; Watson, Rachel E B; Gibbs, Neil K; Costello, Patrick; Baldock, Clair; Weiss, Anthony S; Griffiths, Christopher E M; Sherratt, Michael J

2015-08-01

Excessive ultraviolet radiation (UVR) exposure of the skin is associated with adverse clinical outcomes. Although both exogenous sunscreens and endogenous tissue components (including melanins and tryptophan-derived compounds) reduce UVR penetration, the role of endogenous proteins in absorbing environmental UV wavelengths is poorly defined. Having previously demonstrated that proteins which are rich in UVR-absorbing amino acid residues are readily degraded by broadband UVB-radiation (containing UVA, UVB and UVC wavelengths) here we hypothesised that UV chromophore (Cys, Trp and Tyr) content can predict the susceptibility of structural proteins in skin and the eye to damage by physiologically relevant doses (up to 15.4 J/cm(2)) of solar UVR (95% UVA, 5% UVB). We show that: i) purified suspensions of UV-chromophore-rich fibronectin dimers, fibrillin microfibrils and β- and γ-lens crystallins undergo solar simulated radiation (SSR)-induced aggregation and/or decomposition and ii) exposure to identical doses of SSR has minimal effect on the size or ultrastructure of UV chromophore-poor tropoelastin, collagen I, collagen VI microfibrils and α-crystallin. If UV chromophore content is a factor in determining protein stability in vivo, we would expect that the tissue distribution of Cys, Trp and Tyr-rich proteins would correlate with regional UVR exposure. From bioinformatic analysis of 244 key structural proteins we identified several biochemically distinct, yet UV chromophore-rich, protein families. The majority of these putative UV-absorbing proteins (including the late cornified envelope proteins, keratin associated proteins, elastic fibre-associated components and β- and γ-crystallins) are localised and/or particularly abundant in tissues that are exposed to the highest doses of environmental UVR, specifically the stratum corneum, hair, papillary dermis and lens. We therefore propose that UV chromophore-rich proteins are localised in regions of high UVR exposure as a consequence of an evolutionary pressure to express sacrificial protein sunscreens which reduce UVR penetration and hence mitigate tissue damage. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Electrosurgery: principles and practice to reduce risk and maximize efficacy.

PubMed

Brill, Andrew I

2011-12-01

Science becomes art and art becomes function when fundamental principles are utilized to dictate surgical practice. Most important, the risk for inadvertent thermal injury during electrosurgery can be minimized by a sound comprehension of the predictable behaviors of electricity in living tissue.Guided by the Hippocratic charge of primum non nocere, the ultimate aim of energy-assisted surgery is the attainment of anatomic dissection and hemostasis with the least amount of collateral damage and subsequent scar tissue formation.Ideally, the surgeon’s final view of the operative field should accurately approximate the topography discoverable after postoperative healing. Despite the continued innovation of products borne to reduce thermal damage and then marketed as being comparatively safer, it is the hands and mind of the surgeon that serve to preserve tissue integrity by reducing the burden of delayed thermal necrosis and taking steps to prevent excessive devitalization of tissue. Regardless of the chosen modality, the inseparable and exponentially linked elements of time and the quantity of delivered energy must be integrated while purposefully moderating to attain the desired tissue effect. Ultimately, the reduction of unwanted thermal injury is inherently linked to good surgical judgment and technique, a sound comprehension of the applied energy modality, and the surgeon’s ability to recognize anatomic structures within the field of surgical dissection as well as those within the zone of significant thermal change.During the use of any energy-based device for hemostasis, out of sight must never mean out of mind. If the bowel, bladder, or ureter is in close proximity to a bleeder,they should be sufficiently mobilized before applying energy. Thermal energy should always be withheld until an orderly sequence of anatomic triage is carried out.Whenever a vital structure cannot be adequately mobilized, hemorrhage is preferentially controlled by using mechanical tamponade or suture ligature.

A potential role for endogenous proteins as sacrificial sunscreens and antioxidants in human tissues

PubMed Central

Hibbert, Sarah A.; Watson, Rachel E.B.; Gibbs, Neil K.; Costello, Patrick; Baldock, Clair; Weiss, Anthony S.; Griffiths, Christopher E.M.; Sherratt, Michael J.

2015-01-01

Excessive ultraviolet radiation (UVR) exposure of the skin is associated with adverse clinical outcomes. Although both exogenous sunscreens and endogenous tissue components (including melanins and tryptophan-derived compounds) reduce UVR penetration, the role of endogenous proteins in absorbing environmental UV wavelengths is poorly defined. Having previously demonstrated that proteins which are rich in UVR-absorbing amino acid residues are readily degraded by broadband UVB-radiation (containing UVA, UVB and UVC wavelengths) here we hypothesised that UV chromophore (Cys, Trp and Tyr) content can predict the susceptibility of structural proteins in skin and the eye to damage by physiologically relevant doses (up to 15.4 J/cm2) of solar UVR (95% UVA, 5% UVB). We show that: i) purified suspensions of UV-chromophore-rich fibronectin dimers, fibrillin microfibrils and β- and γ-lens crystallins undergo solar simulated radiation (SSR)-induced aggregation and/or decomposition and ii) exposure to identical doses of SSR has minimal effect on the size or ultrastructure of UV chromophore-poor tropoelastin, collagen I, collagen VI microfibrils and α-crystallin. If UV chromophore content is a factor in determining protein stability in vivo, we would expect that the tissue distribution of Cys, Trp and Tyr-rich proteins would correlate with regional UVR exposure. From bioinformatic analysis of 244 key structural proteins we identified several biochemically distinct, yet UV chromophore-rich, protein families. The majority of these putative UV-absorbing proteins (including the late cornified envelope proteins, keratin associated proteins, elastic fibre-associated components and β- and γ-crystallins) are localised and/or particularly abundant in tissues that are exposed to the highest doses of environmental UVR, specifically the stratum corneum, hair, papillary dermis and lens. We therefore propose that UV chromophore-rich proteins are localised in regions of high UVR exposure as a consequence of an evolutionary pressure to express sacrificial protein sunscreens which reduce UVR penetration and hence mitigate tissue damage. PMID:25911998

Recent Advances of Light-Mediated Theranostics

PubMed Central

Ai, Xiangzhao; Mu, Jing; Xing, Bengang

2016-01-01

Currently, precision theranostics have been extensively demanded for the effective treatment of various human diseases. Currently, efficient therapy at the targeted disease areas still remains challenging since most available drug molecules lack of selectivity to the pathological sites. Among different approaches, light-mediated therapeutic strategy has recently emerged as a promising and powerful tool to precisely control the activation of therapeutic reagents and imaging probes in vitro and in vivo, mostly attributed to its unique properties including minimally invasive capability and highly spatiotemporal resolution. Although it has achieved initial success, the conventional strategies for light-mediated theranostics are mostly based on the light with short wavelength (e.g., UV or visible light), which may usually suffer from several undesired drawbacks, such as limited tissue penetration depth, unavoidable light absorption/scattering and potential phototoxicity to healthy tissues, etc. Therefore, a near-infrared (NIR) light-mediated approach on the basis of long-wavelength light (700-1000 nm) irradiation, which displays deep-tissue penetration, minimized photo-damage and low autofluoresence in living systems, has been proposed as an inspiring alternative for precisely phototherapeutic applications in the last decades. Despite numerous NIR light-responsive molecules have been currently proposed for clinical applications, several inherent drawbacks, such as troublesome synthetic procedures, low water solubility and limited accumulation abilities in targeted areas, heavily restrict their applications in deep-tissue therapeutic and imaging studies. Thanks to the amazing properties of several nanomaterials with large extinction coefficient in the NIR region, the construction of NIR light responsive nanoplatforms with multifunctions have become promising approaches for deep-seated diseases diagnosis and therapy. In this review, we summarized various light-triggered theranostic strategies and introduced their great advances in biomedical applications in recent years. Moreover, some other promising light-assisted techniques, such as photoacoustic and Cerenkov radiation, were also systemically discussed. Finally, the potential challenges and future perspectives for light-mediated deep-tissue diagnosis and therapeutics were proposed. PMID:27877246

Biomechanics Analysis of Pressure Ulcer Using Damaged Interface Model between Bone and Muscle in the Human Buttock

NASA Astrophysics Data System (ADS)

Slamet, Samuel Susanto; Takano, Naoki; Tanabe, Yoshiyuki; Hatano, Asako; Nagasao, Tomohisa

This paper aims at building up a computational procedure to study the bio-mechanism of pressure ulcer using the finite element method. Pressure ulcer is a disease that occurs in the human body after 2 hours of continuous external force. In the very early stage of pressure ulcer, it is found that the tissues inside the body are damaged, even though skin surface looks normal. This study assumes that tension and/or shear strain will cause damage to loose fibril tissue between the bone and muscle and that propagation of damaged area will lead to fatal stage. Analysis was performed using the finite element method by modeling the damaged fibril tissue as a cutout. By varying the loading directions and watching both tensile and shear strains, the risk of fibril tissue damage and propagation of the damaged area is discussed, which may give new insight for the careful nursing for patients, particularly after surgical treatment. It was found that the pressure ulcer could reoccur for a surgical flap treatment. The bone cut and surgical flap surgery is not perfect to prevent the bone-muscle interfacial damage.

Fast and automatic depth control of iterative bone ablation based on optical coherence tomography data

NASA Astrophysics Data System (ADS)

Fuchs, Alexander; Pengel, Steffen; Bergmeier, Jan; Kahrs, Lüder A.; Ortmaier, Tobias

2015-07-01

Laser surgery is an established clinical procedure in dental applications, soft tissue ablation, and ophthalmology. The presented experimental set-up for closed-loop control of laser bone ablation addresses a feedback system and enables safe ablation towards anatomical structures that usually would have high risk of damage. This study is based on combined working volumes of optical coherence tomography (OCT) and Er:YAG cutting laser. High level of automation in fast image data processing and tissue treatment enables reproducible results and shortens the time in the operating room. For registration of the two coordinate systems a cross-like incision is ablated with the Er:YAG laser and segmented with OCT in three distances. The resulting Er:YAG coordinate system is reconstructed. A parameter list defines multiple sets of laser parameters including discrete and specific ablation rates as ablation model. The control algorithm uses this model to plan corrective laser paths for each set of laser parameters and dynamically adapts the distance of the laser focus. With this iterative control cycle consisting of image processing, path planning, ablation, and moistening of tissue the target geometry and desired depth are approximated until no further corrective laser paths can be set. The achieved depth stays within the tolerances of the parameter set with the smallest ablation rate. Specimen trials with fresh porcine bone have been conducted to prove the functionality of the developed concept. Flat bottom surfaces and sharp edges of the outline without visual signs of thermal damage verify the feasibility of automated, OCT controlled laser bone ablation with minimal process time.

Why do some intervertebral discs degenerate, when others (in the same spine) do not?

PubMed

Adams, Michael A; Lama, Polly; Zehra, Uruj; Dolan, Patricia

2015-03-01

This review suggests why some discs degenerate rather than age normally. Intervertebral discs are avascular pads of fibrocartilage that allow movement between vertebral bodies. Human discs have a low cell density and a limited ability to adapt to mechanical demands. With increasing age, the matrix becomes yellowed, fibrous, and brittle, but if disc structure remains intact, there is little impairment in function, and minimal ingrowth of blood vessels or nerves. Approximately half of old lumbar discs degenerate in the sense of becoming physically disrupted. The posterior annulus and lower lumbar discs are most affected, presumably because they are most heavily loaded. Age and genetic inheritance can weaken discs to such an extent that they are physically disrupted during everyday activities. Damage to the endplate or annulus typically decompresses the nucleus, concentrates stress within the annulus, and allows ingrowth of nerves and blood vessels. Matrix disruption progresses by mechanical and biological means. The site of initial damage leads to two disc degeneration "phenotypes": endplate-driven degeneration is common in the upper lumbar and thoracic spine, and annulus-driven degeneration is common at L4-S1. Discogenic back pain can be initiated by tissue disruption, and amplified by inflammation and infection. Healing is possible in the outer annulus only, where cell density is highest. We conclude that some discs degenerate because they are disrupted by excessive mechanical loading. This can occur without trauma if tissues are weakened by age and genetic inheritance. Moderate mechanical loading, in contrast, strengthens all spinal tissues, including discs. © 2014 Wiley Periodicals, Inc.

Study on the relation between tissues pathologies and traditional chinese medicine syndromes in knee osteoarthritis: Medical image diagnostics by preoperative X-ray and surgical arthroscopy.

PubMed

Tian, Xiangdong; Zhu, Guangyu; Wang, Jian; Wang, Qingfu; Guan, Lei; Tan, Yetong; Xue, Zhipeng; Qin, Lina; Zhang, Jing

2016-04-07

This study aims to investigate whether integration of traditional Chinese medicine and modern medicine has advantage in achieving the improved diagnosis and treatment of knee osteoarthritis. 90 patients with knee osteoarthritis were selected from The Department of Minimal Invasive Joint of The Third Affiliated Hospital of Beijing University of Chinese Medicine from June 2013 to June 2015. They were divided into 3 groups with 30 cases per group in accordance to the syndrome differentiation of traditional Chinese medicine. The patients underwent arthroscopic surgery, and we categorized the patients having the same characterization in each group, and those having distinct difference into the three groups. Based on the arthroscopic analysis, we performed analysis of statistical data in order to analyze the relation between knee osteoarthritis under arthroscope and traditional Chinese medicine syndromes. There are three syndromes according to traditional Chinese medicine that can be categorized into various different groups. The synovial proliferation can be seen mostly in the syndrome of stagnation of blood stasis. The slight damage of knee joint cartilage can be seen in the syndrome of yang deficiency and cold stagnation, the severe one in the syndrome of kidney-marrow deficiency. We found that there are different pathological expressions with the various degree of the tissues damage at the knee and we categorized the knee according to their syndrome. For knee osteoarthritis, different syndromes of traditional Chinese medicine presents different tissues pathological changes at the knee joint under arthroscopy, which will provide objective basis for the diagnosis of this medical condition.

Investigation of the efficacy of ultrafast laser in large bowel excision

NASA Astrophysics Data System (ADS)

Mohanan, Syam Mohan P. C.; Beck, Rainer J.; Góra, Wojciech S.; Perry, Sarah L.; Shires, Mike; Jayne, David; Hand, Duncan P.; Shephard, Jonathan D.

2017-02-01

Local resection of early stage tumors in the large bowel via colonoscopy has been a widely accepted surgical modality for colon neoplasm treatment. The conventional electrocautery techniques used for the resection of neoplasia in the mucosal or submucosal layer of colon tissue has been shown to create obvious thermal necrosis to adjacent healthy tissues and lacks accuracy in resection. Ultrafast picosecond (ps) laser ablation using a wavelength of 1030 or 515 nm is a promising surgical tool to overcome the limitations seen with conventional surgical techniques. The purpose of this initial study is to analyze the depth of ablation or the extent of coagulation deployed by the laser as a function of pulse energy and fluence in an ex-vivo porcine model. Precise control of the depth of tissue removal is of paramount importance for bowel surgery where bowel perforation can lead to morbidity or mortality. Thus we investigate the regimes that are optimal for tissue resection and coagulation through plasma mediated ablation of healthy colon tissue. The ablated tissue samples were analyzed by standard histologic methods and a three dimensional optical profilometer technique. We demonstrate that ultrafast laser resection of colonic tissue can minimize the region of collateral thermal damage (<50 μm) with a controlled ablation depth. This surgical modality allows potentially easier removal of early stage lesions and has the capability to provide more control to the surgeon in comparison with a mechanical or electrocautery device.

Optimizing fluence and debridement effects on cutaneous resurfacing carbon dioxide laser surgery.

PubMed

Weisberg, N K; Kuo, T; Torkian, B; Reinisch, L; Ellis, D L

1998-10-01

To develop methods to compare carbon dioxide (CO2) resurfacing lasers, fluence, and debridement effects on tissue shrinkage and histological thermal denaturation. In vitro human or in vivo porcine skin samples received up to 5 passes with scanner or short-pulsed CO2 resurfacing lasers. Fluences ranging from 2.19 to 17.58 J/cm2 (scanner) and 1.11 to 5.56 J/cm2 (short pulsed) were used to determine each laser's threshold energy for clinical effect. Variable amounts of debridement were also studied. Tissue shrinkage was evaluated by using digital photography to measure linear distance change of the treated tissue. Tissue histological studies were evaluated using quantitative computer image analysis. Fluence-independent in vitro tissue shrinkage was seen with the scanned and short-pulsed lasers above threshold fluence levels of 5.9 and 2.5 J/cm2, respectively. Histologically, fluence-independent thermal depths of damage of 77 microns (scanner) and 25 microns (pulsed) were observed. Aggressive debridement of the tissue increased the shrinkage per pass of the laser, and decreased the fluence required for the threshold effect. In vivo experiments confirmed the in vitro results, although the in vivo threshold fluence level was slightly higher and the shrinkage obtained was slightly lower per pass. Our methods allow comparison of different resurfacing lasers' acute effects. We found equivalent laser tissue effects using lower fluences than those currently accepted clinically. This suggests that the morbidity associated with CO2 laser resurfacing may be minimized by lowering levels of tissue input energy and controlling for tissue debridement.

High quality tissue miniarray technique using a conventional TV/radio telescopic antenna.

PubMed

Elkablawy, Mohamed A; Albasri, Abdulkader M

2015-01-01

The tissue microarray (TMA) is widely accepted as a fast and cost-effective research tool for in situ tissue analysis in modern pathology. However, the current automated and manual TMA techniques have some drawbacks restricting their productivity. Our study aimed to introduce an improved manual tissue miniarray (TmA) technique that is simple and readily applicable to a broad range of tissue samples. In this study, a conventional TV/radio telescopic antenna was used to punch tissue cores manually from donor paraffin embedded tissue blocks which were pre-incubated at 40oC. The cores were manually transferred, organized and attached to a standard block mould, and filled with liquid paraffin to construct TmA blocks without any use of recipient paraffin blocks. By using a conventional TV/radio antenna, it was possible to construct TmA paraffin blocks with variable formats of array size and number (2-mm x 42, 2.5-mm x 30, 3-mm x 24, 4-mm x 20 and 5-mm x 12 cores). Up to 2-mm x 84 cores could be mounted and stained on a standard microscopic slide by cutting two sections from two different blocks and mounting them beside each other. The technique was simple and caused minimal damage to the donor blocks. H and E and immunostained slides showed well-defined tissue morphology and array configuration. This technique is easy to reproduce, quick, inexpensive and creates uniform blocks with abundant tissues without specialized equipment. It was found to improve the stability of the cores within the paraffin block and facilitated no losses during cutting and immunostaining.

Radiofrequency ablation of the pancreas with and without intraluminal duodenal cooling in a porcine model.

PubMed

Fegrachi, Samira; Molenaar, I Quintus; Klaessens, John H; Besselink, Marc G; Offerhaus, Johan A; van Hillegersberg, Richard

2013-10-01

To determine the short-term outcome of radiofrequency ablation (RFA) of pancreatic tissue near the duodenum and portomesenteric vessels (PMV) in a porcine model with and without intraluminal duodenal cooling. RFA has been proposed as a new treatment strategy in patients with unresectable locally advanced pancreatic cancer. RFA may cause thermal damage to the duodenum and vascular structures, but these risks and potential protective measures have never been systematically addressed. Intraluminal duodenal cooling during RFA could prevent thermal damage to the duodenum. RFA was performed in 11 pigs during laparotomy with a bipolar probe of 30 mm active length at a power of 30 W until a total energy of 15 kJ was administered. The RFA probe was inserted in the pancreas at 5 or 15 mm from the duodenum, PMV, and in the pancreatic tail. RFA near the duodenum was performed with and without intraluminal duodenal cooling using 100 mL/min saline of 5°C. Histopathologic assessment was performed. The maximum RFA-induced temperature was 92°C. RFA with one single probe induced adequate ablation lesions with a diameter of 20 mm over a length of 30 mm. Without duodenal cooling, RFA induced duodenal thermal damage, whereas with duodenal cooling, no damage was observed. RFA at 15 mm from the PMV resulted in minimal superficial focal vascular damage, without thrombosis or hemorrhage. RFA provides adequate ablation zones in the pancreas of the porcine. Thermal damage to the duodenum can be prevented by intraluminal duodenal cooling without loss of ablation effectivity. Copyright © 2013 Elsevier Inc. All rights reserved.

Effects of soft X-ray radiation damage on paraffin-embedded rat tissues supported on ultralene: a chemical perspective.

PubMed

Bedolla, Diana E; Mantuano, Andrea; Pickler, Arissa; Mota, Carla Lemos; Braz, Delson; Salata, Camila; Almeida, Carlos Eduardo; Birarda, Giovanni; Vaccari, Lisa; Barroso, Regina Cély; Gianoncelli, Alessandra

2018-05-01

Radiation damage is an important aspect to be considered when analysing biological samples with X-ray techniques as it can induce chemical and structural changes in the specimens. This work aims to provide new insights into the soft X-ray induced radiation damage of the complete sample, including not only the biological tissue itself but also the substrate and embedding medium, and the tissue fixation procedure. Sample preparation and handling involves an unavoidable interaction with the sample matrix and could play an important role in the radiation-damage mechanism. To understand the influence of sample preparation and handling on radiation damage, the effects of soft X-ray exposure at different doses on ultralene, paraffin and on paraffin-embedded rat tissues were studied using Fourier-transform infrared (FTIR) microspectroscopy and X-ray microscopy. Tissues were preserved with three different commonly used fixatives: formalin, glutaraldehyde and Karnovsky. FTIR results showed that ultralene and paraffin undergo a dose-dependent degradation of their vibrational profiles, consistent with radiation-induced oxidative damage. In addition, formalin fixative has been shown to improve the preservation of the secondary structure of proteins in tissues compared with both glutaraldehyde and Karnovsky fixation. However, conclusive considerations cannot be drawn on the optimal fixation protocol because of the interference introduced by both substrate and embedding medium in the spectral regions specific to tissue lipids, nucleic acids and carbohydrates. Notably, despite the detected alterations affecting the chemical architecture of the sample as a whole, composed of tissue, substrate and embedding medium, the structural morphology of the tissues at the micrometre scale is essentially preserved even at the highest exposure dose.

Development of novel force-limiting grasping forceps with a simple mechanism.

PubMed

Sakaguchi, Yasuto; Sato, Toshihiko; Yutaka, Yojiro; Muranishi, Yusuke; Komatsu, Teruya; Yoshizawa, Akihiko; Nakajima, Naoki; Nakamura, Tatsuo; Date, Hiroshi

2018-06-06

In endoscopic surgery, fragile tissues may be damaged by the application of excessive force. Thus, we developed novel endoscopic forceps with a simple force-limiting mechanism. The novel forceps were constructed with a leaf spring, and the spring thickness determines grasping pressure. We established an evaluation system (maximum score is 11 points) for lung tissue damage leading to complications. We tested the conventional forceps (186.8 kPa) and 3 novel spring forceps with the following thicknesses: 1.3 mm (53.0 kPa), 2.2 mm (187.7 kPa) and 2.8 mm (369.2 kPa). After grasping, peripheral canine lung tissues were microscopically examined for acute- and late-phase damages. In the acute phase (20 sites), the novel forceps caused capillary congestion and haemorrhage in the subpleural tissue, whereas the conventional forceps caused deep tissue and pleural damages. In the late phase (30 sites), both forceps caused fibroblast formation and interstitial thickening, which progressed to the deeper tissues as grasping pressure increased. In the acute phase, the median scores were 2.0 and 6.0 for the novel and conventional forceps, respectively (P = 0.003). In the late phase, the median scores were 2.0, 2.5 and 5.0 for 1.3-, 2.2- and 2.8-mm thick forceps, respectively, and 5.0 for the conventional forceps (P < 0.001). In both phases, the novel forceps with grasping pressure set below 187.7 kPa (2.2 mm) caused significantly less lung tissue damage than the conventional forceps. The novel endoscopic forceps are able to regulate the tissue-grasping pressure and induce less damage in lung tissues than conventional forceps.

Non-contact hematoma damage and healing assessment using reflectance photoplethysmographic imaging

NASA Astrophysics Data System (ADS)

Amelard, Robert; Pfisterer, Kaylen J.; Clausi, David A.; Wong, Alexander

2016-03-01

Impact trauma may cause a hematoma, which is the leakage of venous blood into surrounding tissues. Large hematomas can be dangerous as they may inhibit local blood ow. Hematomas are often diagnosed visually, which may be problematic if the hematoma leaks deeper than the visible penetration depth. Furthermore, vascular wound healing is often monitored at home without the aid of a clinician. We therefore investigated the use of near infrared (NIR) re ectance photoplethysmographic imaging (PPGI) to assess vascular damage resulting from a hematoma, and monitor the healing process. In this case study, the participant experienced internal vascular damage in the form of a hematoma. Using a PPGI system with dual-mode temporally coded illumination for ambient-agnostic data acquisition and mounted optical elements, the tissue was illuminated with a spatially uniform irradiance pattern of 850 nm wavelength light for increased tissue penetration and high oxy-to-deoxyhemoglobin absorption ratio. Initial and follow-up PPGI data collection was performed to assess vascular damage and healing. The tissue PPGI sequences were spectrally analyzed, producing spectral maps of the tissue area. Experimental results show that spatial differences in spectral information can be observed around the damaged area. In particular, the damaged site exhibited lower pulsatility than the surrounding healthy tissue. This pulsatility was largely restored in the follow-up data, suggesting that the tissue had undergone vascular healing. These results indicate that hematomas can be assessed and monitored in a non-contact visual manner, and suggests that PPGI can be used for tissue health assessment, with potential extensions to peripheral vascular disease.

Synchrotron microbeam irradiation induces neutrophil infiltration, thrombocyte attachment and selective vascular damage in vivo

PubMed Central

Brönnimann, Daniel; Bouchet, Audrey; Schneider, Christoph; Potez, Marine; Serduc, Raphaël; Bräuer-Krisch, Elke; Graber, Werner; von Gunten, Stephan; Laissue, Jean Albert; Djonov, Valentin

2016-01-01

Our goal was the visualizing the vascular damage and acute inflammatory response to micro- and minibeam irradiation in vivo. Microbeam (MRT) and minibeam radiation therapies (MBRT) are tumor treatment approaches of potential clinical relevance, both consisting of parallel X-ray beams and allowing the delivery of thousands of Grays within tumors. We compared the effects of microbeams (25–100 μm wide) and minibeams (200–800 μm wide) on vasculature, inflammation and surrounding tissue changes during zebrafish caudal fin regeneration in vivo. Microbeam irradiation triggered an acute inflammatory response restricted to the regenerating tissue. Six hours post irradiation (6 hpi), it was infiltrated by neutrophils and fli1a+ thrombocytes adhered to the cell wall locally in the beam path. The mature tissue was not affected by microbeam irradiation. In contrast, minibeam irradiation efficiently damaged the immature tissue at 6 hpi and damaged both the mature and immature tissue at 48 hpi. We demonstrate that vascular damage, inflammatory processes and cellular toxicity depend on the beam width and the stage of tissue maturation. Minibeam irradiation did not differentiate between mature and immature tissue. In contrast, all irradiation-induced effects of the microbeams were restricted to the rapidly growing immature tissue, indicating that microbeam irradiation could be a promising tumor treatment tool. PMID:27640676

Molecular level detection and localization of mechanical damage in collagen enabled by collagen hybridizing peptides.

PubMed

Zitnay, Jared L; Li, Yang; Qin, Zhao; San, Boi Hoa; Depalle, Baptiste; Reese, Shawn P; Buehler, Markus J; Yu, S Michael; Weiss, Jeffrey A

2017-03-22

Mechanical injury to connective tissue causes changes in collagen structure and material behaviour, but the role and mechanisms of molecular damage have not been established. In the case of mechanical subfailure damage, no apparent macroscale damage can be detected, yet this damage initiates and potentiates in pathological processes. Here, we utilize collagen hybridizing peptide (CHP), which binds unfolded collagen by triple helix formation, to detect molecular level subfailure damage to collagen in mechanically stretched rat tail tendon fascicle. Our results directly reveal that collagen triple helix unfolding occurs during tensile loading of collagenous tissues and thus is an important damage mechanism. Steered molecular dynamics simulations suggest that a likely mechanism for triple helix unfolding is intermolecular shearing of collagen α-chains. Our results elucidate a probable molecular failure mechanism associated with subfailure injuries, and demonstrate the potential of CHP targeting for diagnosis, treatment and monitoring of tissue disease and injury.

A 3D intestinal tissue model supports Clostridioides difficile germination, colonization, toxin production and epithelial damage.

PubMed

Shaban, Lamyaa; Chen, Ying; Fasciano, Alyssa C; Lin, Yinan; Kaplan, David L; Kumamoto, Carol A; Mecsas, Joan

2018-04-01

Endospore-forming Clostridioides difficile is a causative agent of antibiotic-induced diarrhea, a major nosocomial infection. Studies of its interactions with mammalian tissues have been hampered by the fact that C. difficile requires anaerobic conditions to survive after spore germination. We recently developed a bioengineered 3D human intestinal tissue model and found that low O 2 conditions are produced in the lumen of these tissues. Here, we compared the ability of C. difficile spores to germinate, produce toxin and cause tissue damage in our bioengineered 3D tissue model versus in a 2D transwell model in which human cells form a polarized monolayer. 3D tissue models or 2D polarized monolayers on transwell filters were challenged with the non-toxin producing C. difficile CCUG 37787 serotype X (ATCC 43603) and the toxin producing UK1 C. difficile spores in the presence of the germinant, taurocholate. Spores germinated in both the 3D tissue model as well as the 2D transwell system, however toxin activity was significantly higher in the 3D tissue models compared to the 2D transwells. Moreover, the epithelium damage in the 3D tissue model was significantly more severe than in 2D transwells and damage correlated significantly with the level of toxin activity detected but not with the amount of germinated spores. Combined, these results show that the bioengineered 3D tissue model provides a powerful system with which to study early events leading to toxin production and tissue damage of C. difficile with mammalian cells under anaerobic conditions. Furthermore, these systems may be useful for examining the effects of microbiota, novel drugs and other potential therapeutics directed towards C. difficile infections. Copyright © 2018 Elsevier Ltd. All rights reserved.

A polarization sensitive hyperspectral imaging system for detection of differences in tissue properties

NASA Astrophysics Data System (ADS)

Peller, Joseph A.; Ceja, Nancy K.; Wawak, Amanda J.; Trammell, Susan R.

2018-02-01

Polarized light imaging and optical spectroscopy can be used to distinguish between healthy and diseased tissue. In this study, the design and testing of a single-pixel hyperspectral imaging system that uses differences in the polarization of light reflected from tissue to differentiate between healthy and thermally damaged tissue is discussed. Thermal lesions were created in porcine skin (n = 8) samples using an IR laser. The damaged regions were clearly visible in the polarized light hyperspectral images. Reflectance hyperspectral and white light imaging was also obtained for all tissue samples. Sizes of the thermally damaged regions as measured via polarized light hyperspectral imaging are compared to sizes of these regions as measured in the reflectance hyperspectral images and white light images. Good agreement between the sizes measured by all three imaging modalities was found. Hyperspectral polarized light imaging can differentiate between healthy and damaged tissue. Possible applications of this imaging system include determination of tumor margins during cancer surgery or pre-surgical biopsy.

Ginger Treatment Ameliorates Alcohol-induced Myocardial Damage by Suppression of Hyperlipidemia and Cardiac Biomarkers in Rats.

PubMed

Subbaiah, Ganjikunta Venkata; Mallikarjuna, Korivi; Shanmugam, Bhasha; Ravi, Sahukari; Taj, Patan Usnan; Reddy, Kesireddy Sathyavelu

2017-01-01

Alcohol-induced hyperlipidemia is positively correlated with cardiovascular diseases. Several herbal extracts have been reported to protect the cardiac injury and suppress the hyperlipidemia. However, the effect of ginger extracts on alcohol-induced hyperlipidemia and associated myocardial damage remains unclear. This study investigated the cardio-protective properties of ginger ethanolic extract (Gt) against alcohol-induced myocardial damage, and further distinguished the association between hyperlipidemia and occurrence of myocardial damage in rats. Twenty four Wistar male albino rats (250 ± 20 g) were divided into four groups including, Normal control (NC) (0.9% NaCl), Ginger treated (Gt) (200 mg/Kg b.w.), Alcohol treated (At) (20% of 6g/kg b.w. alcohol), and Alcohol along with Ginger treatment (At+Gt). In this study, lipid profiles such as fatty acids, triglycerides, total cholesterol, phospholipids, low density lipoprotein and high density lipoproteins, and cardiac biomarkers, including LDH, AST, CK-MB, cTn-T and cTn-I were examined in rats. Furthermore, histopathological studies were also conducted. We found that alcohol-induced myocardial damage was associated with increased lipid profile except high density lipoprotein in alcohol treated (20%, 6g/kg b.w.) rats compared with control. Ginger treatment significantly reduced the alcohol-induced lipid profiles except high density lipoproteins. Furthermore, elevated cardiac biomarkers activity with alcohol intoxication was substantially suppressed by ginger treatment. In addition, ginger treatment for 7-weeks significantly minimized the alcohol-induced myocardial damage. Our results concluded that ginger could protect alcohol-induced myocardial damage by suppression of hyperlipidemia and cardiac biomarkers. Ginger extract could alleviate the myocardial injury partially due to the suppression of circulating FFAs and TG levels.Increased circulating cholesterol, LDL and phospholipids with alcohol intake were substantially suppressed by ginger treatmentAlcohol, induced an increase in cardiac damage biomarkers, CK-MB, cTn-T and cTn-I were remarkably suppressed by ginger treatmentPerformed histopathological studies by transmission electron microscopy and light microscopy shows additional convincing evidence on ginger cardio-protective effects. The drastic changes were rehabilitated in cardiac tissue by ginger treatment may be it acts as a good antioxidant and possessing hypolipidemic activity.Collectively, our findings confirm hypothesis that ginger has cardio protective potential through suppression of hyperlipidemia, preserving the tissue damage bio markers, cardiac biomarkers in plasma and preservation of histoarchitecture of myocytes. Abbreviations used: Gt: Ginger Ethanolic Extract; NC: Normal Control; At: Alcohol treated; MI: Myocardial Infarction.

TNFα-Mediated Liver Destruction by Kupffer Cells and Ly6Chi Monocytes during Entamoeba histolytica Infection

PubMed Central

Ernst, Thomas; Ittrich, Harald; Jacobs, Thomas; Heeren, Joerg; Tacke, Frank; Tannich, Egbert; Lotter, Hannelore

2013-01-01

Amebic liver abscess (ALA) is a focal destruction of liver tissue due to infection by the protozoan parasite Entamoeba histolytica (E. histolytica). Host tissue damage is attributed mainly to parasite pathogenicity factors, but massive early accumulation of mononuclear cells, including neutrophils, inflammatory monocytes and macrophages, at the site of infection raises the question of whether these cells also contribute to tissue damage. Using highly selective depletion strategies and cell-specific knockout mice, the relative contribution of innate immune cell populations to liver destruction during amebic infection was investigated. Neutrophils were not required for amebic infection nor did they appear to be substantially involved in tissue damage. In contrast, Kupffer cells and inflammatory monocytes contributed substantially to liver destruction during ALA, and tissue damage was mediated primarily by TNFα. These data indicate that besides direct antiparasitic drugs, modulating innate immune responses may potentially be beneficial in limiting ALA pathogenesis. PMID:23300453

Omega-3 prevents behavior response and brain oxidative damage in the ketamine model of schizophrenia.

PubMed

Zugno, A I; Chipindo, H L; Volpato, A M; Budni, J; Steckert, A V; de Oliveira, M B; Heylmann, A S; da Rosa Silveira, F; Mastella, G A; Maravai, S G; Wessler, P G; Binatti, A R; Panizzutti, B; Schuck, P F; Quevedo, J; Gama, C S

2014-02-14

Supplementation with omega-3 has been identified as an adjunctive alternative for the treatment of psychiatric disorders, in order to minimize symptoms. Considering the lack of understanding concerning the pathophysiology of schizophrenia, the present study hypothesized that omega 3 prevents the onset of symptoms similar to schizophrenia in young Wistar rats submitted to ketamine treatment. Moreover, the role of oxidative stress in this model was assessed. Omega-3 (0.8g/kg) or vehicle was given by orogastric gavage once daily. Both treatments were performed during 21days, starting at the 30th day of life in young rats. After 14days of treatment with omega-3 or vehicle, a concomitant treatment with saline or ketamine (25mg/kg ip daily) was started and maintained until the last day of the experiment. We evaluated the pre-pulse inhibition of the startle reflex, activity of antioxidant systems and damage to proteins and lipids. Our results demonstrate that supplementation of omega-3 prevented: decreased inhibition of startle reflex, damage to lipids in the hippocampus and striatum and damage to proteins in the prefrontal cortex. Furthermore, these changes are associated with decreased GPx in brain tissues evaluated. Together, our results suggest the prophylactic role of omega-3 against the outcome of symptoms associated with schizophrenia. Copyright © 2014. Published by Elsevier Ltd.

A tissue phantom for visualization and measurement of ultrasound-induced cavitation damage.

PubMed

Maxwell, Adam D; Wang, Tzu-Yin; Yuan, Lingqian; Duryea, Alexander P; Xu, Zhen; Cain, Charles A

2010-12-01

Many ultrasound studies involve the use of tissue-mimicking materials to research phenomena in vitro and predict in vivo bioeffects. We have developed a tissue phantom to study cavitation-induced damage to tissue. The phantom consists of red blood cells suspended in an agarose hydrogel. The acoustic and mechanical properties of the gel phantom were found to be similar to soft tissue properties. The phantom's response to cavitation was evaluated using histotripsy. Histotripsy causes breakdown of tissue structures by the generation of controlled cavitation using short, focused, high-intensity ultrasound pulses. Histotripsy lesions were generated in the phantom and kidney tissue using a spherically focused 1-MHz transducer generating 15 cycle pulses, at a pulse repetition frequency of 100 Hz with a peak negative pressure of 14 MPa. Damage appeared clearly as increased optical transparency of the phantom due to rupture of individual red blood cells. The morphology of lesions generated in the phantom was very similar to that generated in kidney tissue at both macroscopic and cellular levels. Additionally, lesions in the phantom could be visualized as hypoechoic regions on a B-mode ultrasound image, similar to histotripsy lesions in tissue. High-speed imaging of the optically transparent phantom was used to show that damage coincides with the presence of cavitation. These results indicate that the phantom can accurately mimic the response of soft tissue to cavitation and provide a useful tool for studying damage induced by acoustic cavitation. Copyright © 2010 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Neuropsychologist's (re-)view: Resective versus ablative amygdalohippocampectomies.

PubMed

Witt, Juri-Alexander; Hoppe, Christian; Helmstaedter, Christoph

2018-05-01

Pharmacoresistant mesial temporal lobe epilepsy (mTLE) represents the major indication for epilepsy surgery. Since epilepsy surgery is an elective treatment option, preserving cognition is a high priority. Given the essential role of temporomesial structures in declarative long-term memory formation, surgical treatment for mTLE is primarily associated with a risk of material-specific memory decline, but other cognitive domains may be affected as well. The major determinants for the neuropsychological outcome are the functional integrity of surgically affected tissues, the functional reserve capacities of the remnant brain, the postoperative seizure outcome, as well as the quantitative and qualitative changes of antiepileptic drugs. Anterior temporal lobectomy has long been the standard procedure for treating mTLE. However, if an exclusive mesial pathology is present, then functional non-pathological tissues of the temporal pole and neocortex are sacrificed. As a result, more selective or tailored surgical approaches have been developed which strive towards minimizing iatrogenic effects. However, whether or not these approaches are equipotential with regard to seizure control is still a matter of debate. The quality of the presurgical diagnostics could also be decisive. Selective surgery should indeed be selective in terms of preventing evitable collateral cortical damage along the approach. Invasivity and risks of collateral damage associated with "open" selective resective surgery are further minimized by stereotactic ablative surgery via thermocoagulation, or eventually even eliminated by gamma knife surgery. From a neuropsychological point of view, this development is consequent and desirable, but no clear scientific evidence of a superior cognitive outcome after radiosurgery or thermocoagulation currently exists. The studies that are available contain significant methodological limitations. Thus, randomized head-to-head cognitive outcome studies of competing selective procedures are needed, which should meet the minimum requirements for study design and neuropsychological evaluations. Finally, none of the surgical treatment variants can systematically prevent memory decline when the hippocampus is targeted. Copyright © 2017 Elsevier B.V. All rights reserved.

Glycerophospholipid Profiles of Bats with White-Nose Syndrome.

PubMed

Pannkuk, Evan L; McGuire, Liam P; Warnecke, Lisa; Turner, James M; Willis, Craig K R; Risch, Thomas S

2015-01-01

Pseudogymnoascus destructans is an ascomycetous fungus responsible for the disease dubbed white-nose syndrome (WNS) and massive mortalities of cave-dwelling bats. The fungus infects bat epidermal tissue, causing damage to integumentary cells and pilosebaceous units. Differences in epidermal lipid composition caused by P. destructans infection could have drastic consequences for a variety of physiological functions, including innate immune efficiency and water retention. While bat surface lipid and stratum corneum lipid composition have been described, the differences in epidermal lipid content between healthy tissue and P. destructans-infected tissue have not been documented. In this study, we analyzed the effect of wing damage from P. destructans infection on the epidermal polar lipid composition (glycerophospholipids [GPs] and sphingomyelin) of little brown bats (Myotis lucifugus). We hypothesized that infection would lead to lower levels of total lipid or higher oxidized lipid product proportions. Polar lipids from three damaged and three healthy wing samples were profiled by electrospray ionization tandem mass spectrometry. We found lower total broad lipid levels in damaged tissue, specifically ether-linked phospholipids, lysophospholipids, phosphatidylcholine, and phosphatidylethanolamine. Thirteen individual GP species from four broad GP classes were present in higher amounts in healthy tissue. Six unsaturated GP species were absent in damaged tissue. Our results confirm that P. destructans infection leads to altered lipid profiles. Clinical signs of WNS may include lower lipid levels and lower proportions of unsaturated lipids due to cellular and glandular damage.

Drug delivery, cell-based therapies, and tissue engineering approaches for spinal cord injury.

PubMed

Kabu, Shushi; Gao, Yue; Kwon, Brian K; Labhasetwar, Vinod

2015-12-10

Spinal cord injury (SCI) results in devastating neurological and pathological consequences, causing major dysfunction to the motor, sensory, and autonomic systems. The primary traumatic injury to the spinal cord triggers a cascade of acute and chronic degenerative events, leading to further secondary injury. Many therapeutic strategies have been developed to potentially intervene in these progressive neurodegenerative events and minimize secondary damage to the spinal cord. Additionally, significant efforts have been directed toward regenerative therapies that may facilitate neuronal repair and establish connectivity across the injury site. Despite the promise that these approaches have shown in preclinical animal models of SCI, challenges with respect to successful clinical translation still remain. The factors that could have contributed to failure include important biologic and physiologic differences between the preclinical models and the human condition, study designs that do not mirror clinical reality, discrepancies in dosing and the timing of therapeutic interventions, and dose-limiting toxicity. With a better understanding of the pathobiology of events following acute SCI, developing integrated approaches aimed at preventing secondary damage and also facilitating neuroregenerative recovery is possible and hopefully will lead to effective treatments for this devastating injury. The focus of this review is to highlight the progress that has been made in drug therapies and delivery systems, and also cell-based and tissue engineering approaches for SCI. Copyright © 2015 Elsevier B.V. All rights reserved.

Therapeutic efficacy of DL-alpha-lipoic acid on cyclosporine A induced renal alterations.

PubMed

Amudha, Ganapathy; Josephine, Anthony; Mythili, Yenjerla; Sundarapandiyan, Rajaguru; Varalakshmi, Palaninathan

2007-10-01

The present study was designed to evaluate the possible beneficial effect of lipoic acid in preventing the renal damage induced by cyclosporine A in rats. Male albino rats of Wistar strain were divided into four groups and treated as follows. Two groups received cyclosporine A by oral gavage (25 mg/kg/body weight) for 21 days to induce nephrotoxicity, one of which simultaneously received lipoic acid treatment (20 mg/kg body weight) for 21 days. A vehicle (olive oil) and a lipoic acid drug control were also included. Cyclosporine A induced renal damage was evident from the decreased activities of tissue marker enzymes (alkaline phosphatase, acid phosphatase, lactate dehydrogenase, aspartate transaminase and alanine transaminase) and decreased activities of ATPases (Na+, K+-ATPase, Ca2+-ATPase and Mg2+ ATPase). An apparent increase in the levels of serum constituents (urea, uric acid and creatinine) and urinary marker enzymes (N-acetyl-beta-D-glucosaminidase, beta-glucosidase, beta-galactosidase, cathepsin-D and gamma-glutamyl transpeptidase) along with significant decline in creatinine clearance were seen in the cyclosporine treated rats, which was reversed upon treatment with lipoic acid. Ultrastructural observations were also in agreement with the above abnormal changes. Lipoic acid effectively reverted these abnormal biochemical changes and minimized the morphological lesions in renal tissue. Hence, this study clearly exemplifies that lipoic acid might be an ideal choice against cyclosporine A induced cellular abnormalities.

308-nm excimer laser ablation of human cartilage

NASA Astrophysics Data System (ADS)

Prodoehl, John A.; Rhodes, Anthony L.; Meller, Menachem M.; Sherk, Henry H.

1993-07-01

The XeCl excimer laser was investigated as an ablating tool for human fibrocartilage and hyaline cartilage. Quantitative measurements were made of tissue ablation rates as a function of fluence in meniscal fibrocartilage and articular hyaline cartilage. A force of 1.47 Newtons was applied to an 800 micrometers fiber with the laser delivering a range of fluences (40 to 190 mj/mm2) firing at a frequency of 5 Hz. To assess the effect of repetition rate on ablation rate, a set of measurements was made at a constant fluence of 60 mj/mm2, with the repetition rate varying from 10 to 40 Hz. Histologic and morphometric analysis was performed using light microscopy. The results of these studies revealed that the ablation rate was directly proportional to fluence over the range tested. Fibrocartilage was ablated at a rate 2.56 times faster than hyaline cartilage at the maximum fluence tested. Repetition rate had no effect on the penetration per pulse. Adjacent tissue damage was noted to be minimal (10 - 70 micrometers ).

Analytical modeling of hyperthermia using magnetic nanoparticles

NASA Astrophysics Data System (ADS)

Bensenane, Mohamed Nassim; Senoudi, Assia Rachida; Benmouna, Reda; Ould-Kaddour, Fouzia

2018-06-01

Hyperthermia using magnetic nanoparticles (MNPs) is one of many techniques to treat cancer causing minimal damage to healthy tissues. In the present work we give an analytical resolution of the bio-heat equation (based on Pennes model) providing the temperature rise as a function of the characteristics of the magnetic nanoparticles, the applied magnetic field and the biological properties of the tissue. The temperature inside the tumor was found to be very sensitive to the frequency f of alternating magnetic field, magnetic field amplitude H0 and volume fraction φ. This study optimizes the intensity of magnetic field to reach ideal hyperthermia conditions. When f varies between 50 and 150 KHz, temperature increases from 39 °C until 53 °C; when H0 is ranged from 5 - 15 kA/m, it increases from 39.5 °C until 49 °C, and when volume fraction φ of MNPs is ranged from 2 × 10-4 to 3 × 10-4 it increases from 44 °C until 48 °C.

Heat localization for targeted tumor treatment with nanoscale near-infrared radiation absorbers

PubMed Central

Xie, Bin; Singh, Ravi; Torti, F. M.; Keblinski, Pawel; Torti, Suzy

2012-01-01

Focusing heat delivery while minimizing collateral damage to normal tissues is essential for successful nanoparticle-mediated laser-induced thermal cancer therapy. We present thermal maps obtained via magnetic resonance imaging (MRI) characterizing laser heating of a phantom tissue containing a multiwalled carbon nanotube inclusion. The data demonstrate that heating continuously over tens of seconds leads to poor localization (~ 0.5 cm) of the elevated temperature region. By contrast, for the same energy input, heat localization can be reduced to the millimeter rather than centimeter range by increasing the laser power and shortening the pulse duration. The experimental data can be well understood within a simple diffusive heat conduction model. Analysis of the model indicates that to achieve 1 mm or better resolution, heating pulses of ~ 2s or less need to be used with appropriately higher heating power. Modeling these data using a diffusive heat conduction analysis predicts parameters for optimal targeted delivery of heat for ablative therapy. PMID:22948207

Laser surgery: using the carbon dioxide laser.

PubMed Central

Wright, V. C.

1982-01-01

In 1917 Einstein theorized tha through an atomic process a unique kind of electromagnetic radiation could be produced by stimulated emission. When such radiation is in the optical or infrared spectrum it is termed laser (light amplification by stimulated emission of radiation) light. A laser, a high-intensity light source, emits a nearly parallel electromagnetic beam of energy at a given wavelength that can be captured by a lens and concentrated in the focal spot. The wavelength determines how the laser will be used. The carbon dioxide laser is now successfully employed for some surgical procedures in gynecology, otorhinolaryngology, neurosurgery, and plastic and general surgery. The CO2 laser beam is directed through the viewing system of an operating microscope or through a hand-held laser component. Its basic action in tissue is thermal vaporization; it causes minimal damage to adjacent tissues. Surgeons require special training in the basic methods and techniques of laser surgery, as well as in the safety standards that must be observed. Images FIG. 5 PMID:7074503

Sarcocystis and Its Complications in Camels (Camelus dromedarius) of Eastern Provinces of Iran

PubMed Central

Valinezhad, Akbar; Ahmadi, Nasrollah

2008-01-01

The prevalence of Sarcocystis spp. was investigated by gross and histopathological examinations in 250 camels (Camelus dromedarius) slaughtered from 2002 to 2005 in the Mashhad Slaughterhouse, eastern Iran. Samples were taken from the diaphragm, heart, tongue, esophagus and masseter muscles for histopathological studies. No macroscopic sarcocysts were found in the samples at gross inspection. Sarcocysts were detected in 209 of 250 (83.6%) examined camels at histopathological level. The infection rate of the esophagus, heart, masseter muscles, diaphragm, and tongue was 58.8%, 48.0%, 46.8%, 41.6%, and 28.0%, respectively. There was no significant difference in the rate of infection between male (85.8%) and female (81.0%) camels. The tissue response to vital cysts was minimal; however, reaction to the degenerating cysts was severe and caused tissue damages resulting in hyperemia, hemorrhages, mononuclear cell infiltration, necrotic changes, and fibrosis. The wild and domestic carnivores especially dogs may be the final hosts of Sarcocystis spp. in this area. PMID:19127328

Synthesis of a fine neurological electrode by plasma polymerization processing.

PubMed

Cannon, J G; Dillon, R O; Bunshah, R F; Crandall, P H; Dymond, A M

1980-05-01

This research is part of a continuing program for the development of a coaxial depth electrode for research and diagnostic studies of neurological diseases. The requirements for this electrode include (1) strength and resistance to buckling sufficient to ensure self-forced penetration of brain tissue to a depth of 6 cm; (2) biocompatibility of the materials employed; (3) resistance to brittle fracture; and (4) a total diameter of less than 200 micrometer to minimize tissue damage. Earlier synthesis efforts using chemical vapor deposition techniques have been successful, although the process yield was 40% and an outer insulating layer had yet to be deposited. Plasma polymerization processes have been employed to realize an increase in the yield and provide an outer insulating layer. The starting material is W-26 at.% Re wire, nominally 125 micrometer in diameter. Hexamethyldisilazane(CH3)3SiNHSi(CH3)3 is used to deposit the insulating layers. The paper describes factors influencing the choice of materials, deposition techniques, and properties of electrodes.

A bio-ballistic micro-jet for drug injection into animal skin using a Nd:YAG laser

NASA Astrophysics Data System (ADS)

Yoh, J. J.; Jang, H.; Park, M.; Han, T.; Hah, J.

2016-01-01

Imaging of the abdominal skin of a guinea pig after injecting a fluorescent probe and biotin via the laser-induced ballistic technique revealed the epidermal and dermal layers which were stained well below 60 \\upmu m underneath the outer layer of the skin. An extensive network of cells was evident in the deeper layer of the stained dermis as the distributed fluorescein isothiocyanate dose was administered by repeated injection using a laser-based micro-jet. We performed optically controlled release of the drug by breaching the guinea pig's skin tissue targeting the region 10-400 \\upmu m beneath the outermost layer. Tissue damage was minimized by reducing the injection volume to approximately 100 nl per pulse. This was done using a micro-jet diameter equal to half of that of a conventional 200 \\upmu m syringe needle. Thus, the optimally controlled delivery of liquid drugs using an irradiated laser pulse was shown to be possible.

Characterization of Therapeutic Coatings on Medical Devices

NASA Astrophysics Data System (ADS)

Wormuth, Klaus

Therapeutic coatings on medical devices such as catheters, guide wires, and stents improve biocompatibility by favorably altering the chemical nature of the device/tissue or device/blood interface. Such coatings often minimize tissue damage (reduce friction), decrease chances for blood clot formation (prevent platelet adsorption), and improve the healing response (deliver drugs). Confocal Raman microscopy provides valuable information about biomedical coatings by, for example, facilitating the measurement of the thickness and swelling of frictionreducing hydrogel coatings on catheters and by determining the distribution of drug within a polymer-based drug-eluting coatings on stents. This chapter explores the application of Raman microscopy to the imaging of thin coatings of cross-linked poly(vinyl pyrrolidone) gels, parylene films, mixtures of dexamethasone with various polymethacrylates, and mixtures of rapamycin with hydrolysable (biodegradable) poly(lactide-co-glycolide) polymers. Raman microscopy measures the thickness and swelling of coatings, reveals the degree of mixing of drug and polymer, senses the hydrolysis of biodegradable polymers, and determines the polymorphic forms of drug present within thin therapeutic coatings on medical devices.

Feasibility of Using a Novel 2.45 GHz Double Short Distance Slot Coaxial Antenna for Minimally Invasive Cancer Breast Microwave Ablation Therapy: Computational Model, Phantom, and In Vivo Swine Experimentation

PubMed Central

Cepeda Rubio, M. F. J.; Leija, L.

2018-01-01

Microwave ablation (MWA) by using coaxial antennas is a promising alternative for breast cancer treatment. A double short distance slot coaxial antenna as a newly optimized applicator for minimally invasive treatment of breast cancer is proposed. To validate and to analyze the feasibility of using this method in clinical treatment, a computational model, phantom, and breast swine in vivo experimentation were carried out, by using four microwave powers (50 W, 30 W, 20 W, and 10 W). The finite element method (FEM) was used to develop the computational model. Phantom experimentation was carried out in breast phantom. The in vivo experimentation was carried out in a 90 kg swine sow. Tissue damage was estimated by comparing control and treated micrographs of the porcine mammary gland samples. The coaxial slot antenna was inserted in swine breast glands by using image-guided ultrasound. In all cases, modeling, in vivo and phantom experimentation, and ablation temperatures (above 60°C) were reached. The in vivo experiments suggest that this new MWA applicator could be successfully used to eliminate precise and small areas of tissue (around 20–30 mm2). By modulating the power and time applied, it may be possible to increase/decrease the ablation area. PMID:29854360

Optically based quantification of absolute cerebral metabolic rate of oxygen (CMRO2) with high spatial resolution in rodents

NASA Astrophysics Data System (ADS)

Yaseen, Mohammad A.; Srinivasan, Vivek J.; Sakadžić, Sava; Vinogradov, Sergei A.; Boas, David A.

2010-02-01

Measuring oxygen delivery in brain tissue is important for identifying the pathophysiological changes associated with brain injury and various diseases such as cancer, stroke, and Alzheimer's disease. We have developed a multi-modal imaging system for minimally invasive measurement of cerebral oxygenation and blood flow in small animals with high spatial resolution. The system allows for simultaneous measurement of blood flow using Fourier-domain optical coherence tomography, and oxygen partial pressure (pO2) using either confocal or multiphoton phosphorescence lifetime imaging with exogenous porphyrin-based dyes sensitive to dissolved oxygen. Here we present the changes in pO2 and blood flow in superficial cortical vessels of Sprague Dawley rats in response to conditions such as hypoxia, hyperoxia, and functional stimulation. pO2 measurements display considerable heterogeneity over distances that cannot be resolved with more widely used oxygen-monitoring techniques such as BOLD-fMRI. Large increases in blood flow are observed in response to functional stimulation and hypoxia. Our system allows for quantification of cerebral metabolic rate of oxygen (CMRO2) with high spatial resolution, providing a better understanding of metabolic dynamics during functional stimulation and under various neuropathologies. Ultimately, better insight into the underlying mechanisms of neuropathologies will facilitate the development of improved therapeutic strategies to minimize damage to brain tissue.

Minimizing radiation damage in nonlinear optical crystals

DOEpatents

Cooke, D.W.; Bennett, B.L.; Cockroft, N.J.

1998-09-08

Methods are disclosed for minimizing laser induced damage to nonlinear crystals, such as KTP crystals, involving various means for electrically grounding the crystals in order to diffuse electrical discharges within the crystals caused by the incident laser beam. In certain embodiments, electrically conductive material is deposited onto or into surfaces of the nonlinear crystals and the electrically conductive surfaces are connected to an electrical ground. To minimize electrical discharges on crystal surfaces that are not covered by the grounded electrically conductive material, a vacuum may be created around the nonlinear crystal. 5 figs.

Controlled Drug Release and Chemotherapy Response in a Novel Acoustofluidic 3D Tumor Platform.

PubMed

Zervantonakis, Ioannis K; Arvanitis, Costas D

2016-05-01

Overcoming transport barriers to delivery of therapeutic agents in tumors remains a major challenge. Focused ultrasound (FUS), in combination with modern nanomedicine drug formulations, offers the ability to maximize drug transport to tumor tissue while minimizing toxicity to normal tissue. This potential remains unfulfilled due to the limitations of current approaches in accurately assessing and quantifying how FUS modulates drug transport in solid tumors. A novel acoustofluidic platform is developed by integrating a physiologically relevant 3D microfluidic device and a FUS system with a closed-loop controller to study drug transport and assess the response of cancer cells to chemotherapy in real time using live cell microscopy. FUS-induced heating triggers local release of the chemotherapeutic agent doxorubicin from a liposomal carrier and results in higher cellular drug uptake in the FUS focal region. This differential drug uptake induces locally confined DNA damage and glioblastoma cell death in the 3D environment. The capabilities of acoustofluidics for accurate control of drug release and monitoring of localized cell response are demonstrated in a 3D in vitro tumor mode. This has important implications for developing novel strategies to deliver therapeutic agents directly to the tumor tissue while sparing healthy tissue. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Miniature standoff Raman probe for neurosurgical applications

NASA Astrophysics Data System (ADS)

Stevens, Oliver A. C.; Hutchings, Joanne; Gray, William; Vincent, Rosa Louise; Day, John C.

2016-08-01

Removal of intrinsic brain tumors is a delicate process, where a high degree of specificity is required to remove all of the tumor tissue without damaging healthy brain. The accuracy of this process can be greatly enhanced by intraoperative guidance. Optical biopsies using Raman spectroscopy are a minimally invasive and lower-cost alternative to current guidance methods. A miniature Raman probe for performing optical biopsies of human brain tissue is presented. The probe allows sampling inside a conventional stereotactic brain biopsy system: a needle of length 200 mm and inner diameter of 1.8 mm. By employing a miniature stand-off Raman design, the probe removes the need for any additional components to be inserted into the brain. Additionally, the probe achieves a very low internal silica background while maintaining good collection of Raman signal. To illustrate this, the probe is compared with a Raman probe that uses a pair of optical fibers for collection. The miniature stand-off Raman probe is shown to collect a comparable number of Raman scattered photons, but the Raman signal to background ratio is improved by a factor of five at Raman shifts below ˜500 cm-1. The probe's suitability for use on tissue is demonstrated by discriminating between different types of healthy porcine brain tissue.

Application of immunohistochemical staining to detect antigen destruction as a measure of tissue damage.

PubMed

Onul, Abdullah; Colvard, Michael D; Paradise, William A; Elseth, Kim M; Vesper, Benjamin J; Gouvas, Eftychia; Deliu, Zane; Garcia, Kelly D; Pestle, William J; Radosevich, James A

2012-09-01

Electrocautery and directed energy devices (DEDs) such as lasers, which are used in surgery, result in tissue damage that cannot be readily detected by traditional histological methods, such as hematoxylin and eosin staining. Alternative staining methods, including 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) to stain live tissue, have been reported. Despite providing superior detection of damaged tissue relative to the hematoxylin and eosin (H&E) method, the MTT method possesses a number of drawbacks, most notably that it must be carried out on live tissue samples. Herein, we report the development of a novel staining method, "antigen destruction immunohistochemistry" (ADI), which can be carried out on paraffin-embedded tissue. The ADI method takes advantage of epitope loss to define the area of tissue damage and provides many of the benefits of live tissue MTT staining without the drawbacks inherent to that method. In addition, the authors provide data to support the use of antibodies directed at a number of gene products for use in animal tissue for which there are no species-specific antibodies commercially available, as well as an example of a species-specific direct antibody. Data are provided that support the use of this method in many tissue models, as well as evidence that ADI is comparable to the live tissue MTT method.

Application of Immunohistochemical Staining to Detect Antigen Destruction as a Measure of Tissue Damage

PubMed Central

Onul, Abdullah; Colvard, Michael D.; Paradise, William A.; Elseth, Kim M.; Vesper, Benjamin J.; Gouvas, Eftychia; Deliu, Zane; Garcia, Kelly D.; Pestle, William J.

2012-01-01

Electrocautery and directed energy devices (DEDs) such as lasers, which are used in surgery, result in tissue damage that cannot be readily detected by traditional histological methods, such as hematoxylin and eosin staining. Alternative staining methods, including 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) to stain live tissue, have been reported. Despite providing superior detection of damaged tissue relative to the hematoxylin and eosin (H&E) method, the MTT method possesses a number of drawbacks, most notably that it must be carried out on live tissue samples. Herein, we report the development of a novel staining method, “antigen destruction immunohistochemistry” (ADI), which can be carried out on paraffin-embedded tissue. The ADI method takes advantage of epitope loss to define the area of tissue damage and provides many of the benefits of live tissue MTT staining without the drawbacks inherent to that method. In addition, the authors provide data to support the use of antibodies directed at a number of gene products for use in animal tissue for which there are no species-specific antibodies commercially available, as well as an example of a species-specific direct antibody. Data are provided that support the use of this method in many tissue models, as well as evidence that ADI is comparable to the live tissue MTT method. PMID:22723525

Analysis of plastic deformation in cortical bone after insertion of coated and non-coated self-tapping orthopaedic screws.

PubMed

Koistinen, A P; Korhonen, H; Kiviranta, I; Kröger, H; Lappalainen, R

2011-07-01

Insertion of internal fracture fixation devices, such as screws, mechanically weakens the bone. Diamond-like carbon has outstanding tribology properties which may decrease the amount of damage in tissue. The purpose of this study was to investigate methods for quantification of cortical bone damage after orthopaedic bone screw insertion and to evaluate the effect of surface modification on tissue damage. In total, 48 stainless steel screws were inserted into cadaver bones. Half of the screws were coated with a smooth amorphous diamond coating. Geometrical data of the bones was determined by peripheral quantitative computed tomography. Thin sections of the bone samples were prepared after screw insertion, and histomorphometric evaluation of damage was performed on images obtained using light microscopy. Micro-computed tomography and scanning electron microscopy were also used to examine tissue damage. A positive correlation was found between tissue damage and the geometric properties of the bone. The age of the cadaver significantly affected the bone mineral density, as well as the damage perimeter and diameter of the screw hole. However, the expected positive effect of surface modification was probably obscured by large variations in the results and, thus, statistically significant differences were not found in this study. This can be explained by natural variability in bone tissue, which also made automated image analysis difficult.

Arterial embolism

MedlinePlus

... This can result in damage or tissue death ( necrosis ). Arterial emboli often occur in the legs and ... sloughing) of skin Skin erosion ( ulcer ) Tissue death (necrosis; skin is dark and damaged) Symptoms of a ...

Psychomotor performance measured in a virtual environment correlates with technical skills in the operating room.

PubMed

Kundhal, Pavi S; Grantcharov, Teodor P

2009-03-01

This study was conducted to validate the role of virtual reality computer simulation as an objective method for assessing laparoscopic technical skills. The authors aimed to investigate whether performance in the operating room, assessed using a modified Objective Structured Assessment of Technical Skill (OSATS), correlated with the performance parameters registered by a virtual reality laparoscopic trainer (LapSim). The study enrolled 10 surgical residents (3 females) with a median of 5.5 years (range, 2-6 years) since graduation who had similar limited experience in laparoscopic surgery (median, 5; range, 1-16 laparoscopic cholecystectomies). All the participants performed three repetitions of seven basic skills tasks on the LapSim laparoscopic trainer and one laparoscopic cholecystectomy in the operating room. The operating room procedure was video recorded and blindly assessed by two independent observers using a modified OSATS rating scale. Assessment in the operating room was based on three parameters: time used, error score, and economy of motion score. During the tasks on the LapSim, time, error (tissue damage and millimeters of tissue damage [tasks 2-6], error score [incomplete target areas, badly placed clips, and dropped clips [task 7]), and economy of movement parameters (path length and angular path) were registered. The correlation between time, economy, and error parameters during the simulated tasks and the operating room procedure was statistically assessed using Spearman's test. Significant correlations were demonstrated between the time used to complete the operating room procedure and time used for task 7 (r (s) = 0.74; p = 0.015). The error score demonstrated during the laparoscopic cholecystectomy correlated well with the tissue damage in three of the seven tasks (p < 0.05), the millimeters of tissue damage during two of the tasks, and the error score in task 7 (r (s) = 0.67; p = 0.034). Furthermore, statistically significant correlations were observed between the economy of motion score from the operative procedure and LapSim's economy parameters (path length and angular path in six of the tasks) (p < 0.05). The current study demonstrated significant correlations between operative performance in the operating room (assessed using a well-validated rating scale) and psychomotor performance in virtual environment assessed by a computer simulator. This provides strong evidence for the validity of the simulator system as an objective tool for assessing laparoscopic skills. Virtual reality simulation can be used in practice to assess technical skills relevant for minimally invasive surgery.

Dissecting the Molecular Mechanism of Ionizing Radiation-Induced Tissue Damage in the Feather Follicle

PubMed Central

Chen, Xi; Liao, Chunyan; Chu, Qiqi; Zhou, Guixuan; Lin, Xiang; Li, Xiaobo; Lu, Haijie; Xu, Benhua; Yue, Zhicao

2014-01-01

Ionizing radiation (IR) is a common therapeutic agent in cancer therapy. It damages normal tissue and causes side effects including dermatitis and mucositis. Here we use the feather follicle as a model to investigate the mechanism of IR-induced tissue damage, because any perturbation of feather growth will be clearly recorded in its regular yet complex morphology. We find that IR induces defects in feather formation in a dose-dependent manner. No abnormality was observed at 5 Gy. A transient, reversible perturbation of feather growth was induced at 10 Gy, leading to defects in the feather structure. This perturbation became irreversible at 20 Gy. Molecular and cellular analysis revealed P53 activation, DNA damage and repair, cell cycle arrest and apoptosis in the pathobiology. IR also induces patterning defects in feather formation, with disrupted branching morphogenesis. This perturbation is mediated by cytokine production and Stat1 activation, as manipulation of cytokine levels or ectopic Stat1 over-expression also led to irregular feather branching. Furthermore, AG-490, a chemical inhibitor of Stat1 signaling, can partially rescue IR-induced tissue damage. Our results suggest that the feather follicle could serve as a useful model to address the in vivo impact of the many mechanisms of IR-induced tissue damage. PMID:24586618

Stromal regulation of vessel stability by MMP14 and TGFβ

PubMed Central

Sounni, Nor E.; Dehne, Kerstin; van Kempen, Leon; Egeblad, Mikala; Affara, Nesrine I.; Cuevas, Ileana; Wiesen, Jane; Junankar, Simon; Korets, Lidiya; Lee, Jake; Shen, Jennifer; Morrison, Charlotte J.; Overall, Christopher M.; Krane, Stephen M.; Werb, Zena; Boudreau, Nancy; Coussens, Lisa M.

2010-01-01

Innate regulatory networks within organs maintain tissue homeostasis and facilitate rapid responses to damage. We identified a novel pathway regulating vessel stability in tissues that involves matrix metalloproteinase 14 (MMP14) and transforming growth factor beta 1 (TGFβ1). Whereas plasma proteins rapidly extravasate out of vasculature in wild-type mice following acute damage, short-term treatment of mice in vivo with a broad-spectrum metalloproteinase inhibitor, neutralizing antibodies to TGFβ1, or an activin-like kinase 5 (ALK5) inhibitor significantly enhanced vessel leakage. By contrast, in a mouse model of age-related dermal fibrosis, where MMP14 activity and TGFβ bioavailability are chronically elevated, or in mice that ectopically express TGFβ in the epidermis, cutaneous vessels are resistant to acute leakage. Characteristic responses to tissue damage are reinstated if the fibrotic mice are pretreated with metalloproteinase inhibitors or TGFβ signaling antagonists. Neoplastic tissues, however, are in a constant state of tissue damage and exhibit altered hemodynamics owing to hyperleaky angiogenic vasculature. In two distinct transgenic mouse tumor models, inhibition of ALK5 further enhanced vascular leakage into the interstitium and facilitated increased delivery of high molecular weight compounds into premalignant tissue and tumors. Taken together, these data define a central pathway involving MMP14 and TGFβ that mediates vessel stability and vascular response to tissue injury. Antagonists of this pathway could be therapeutically exploited to improve the delivery of therapeutics or molecular contrast agents into tissues where chronic damage or neoplastic disease limits their efficient delivery. PMID:20223936

Does prolonged radiofrequency radiation emitted from Wi-Fi devices induce DNA damage in various tissues of rats?

PubMed

Akdag, Mehmet Zulkuf; Dasdag, Suleyman; Canturk, Fazile; Karabulut, Derya; Caner, Yusuf; Adalier, Nur

2016-09-01

Wireless internet (Wi-Fi) providers have become essential in our daily lives, as wireless technology is evolving at a dizzying pace. Although there are different frequency generators, one of the most commonly used Wi-Fi devices are 2.4GHz frequency generators. These devices are heavily used in all areas of life but the effect of radiofrequency (RF) radiation emission on users is generally ignored. Yet, an increasing share of the public expresses concern on this issue. Therefore, this study intends to respond to the growing public concern. The purpose of this study is to reveal whether long term exposure of 2.4GHz frequency RF radiation will cause DNA damage of different tissues such as brain, kidney, liver, and skin tissue and testicular tissues of rats. The study was conducted on 16 adult male Wistar-Albino rats. The rats in the experimental group (n=8) were exposed to 2.4GHz frequency radiation for over a year. The rats in the sham control group (n=8) were subjected to the same experimental conditions except the Wi-Fi generator was turned off. After the exposure period was complete the possible DNA damage on the rat's brain, liver, kidney, skin, and testicular tissues was detected through the single cell gel electrophoresis assay (comet) method. The amount of DNA damage was measured as percentage tail DNA value. Based on the DNA damage results determined by the single cell gel electrophoresis (Comet) method, it was found that the% tail DNA values of the brain, kidney, liver, and skin tissues of the rats in the experimental group increased more than those in the control group. The increase of the DNA damage in all tissues was not significant (p>0.05). However the increase of the DNA damage in rat testes tissue was significant (p<0.01). In conclusion, long-term exposure to 2.4GHz RF radiation (Wi-Fi) does not cause DNA damage of the organs investigated in this study except testes. The results of this study indicated that testes are more sensitive organ to RF radiation. Copyright © 2016 Elsevier B.V. All rights reserved.

[Specificities in children wound healing].

PubMed

Sanchez, J; Antonicelli, F; Tuton, D; Mazouz Dorval, S; François, C

2016-10-01

Children have specific characteristics of wound healing. The aim of this study was to describe the specific clinical characteristics of wounds healing in children and to present the current knowledge on the specific mechanisms with regard to infant age. The tissue insult or injury in fetus can heal without scar, mainly due to reduced granulation tissue associated to diminished or even no inflammatory phase, modified extracellular matrix such as the concentration of hyaluronic acid in amniotic liquid, expression and arrangement of collagen and tenascin. Thickness of children skin is a serious negative factor in case of trauma, whereas poor co-morbidities and efficient growth tissue mechanisms are beneficial to good evolution, even in cases of extensive damage and loss of tissue. The subsequent tissue mechanical forces, wound healing during childhood, spanning from the age of 2 until the end of puberty, is associated with more hypertrophic scars, both in duration and in intensity. Consequently, unnecessary surgery has to be avoided during this period when possible, and children with abnormal or pathologic wound healing should benefit from complementary treatments (hydration, massage, brace, silicone, hydrotherapy…), which represent efficient factors to minimize tissue scarring. After wound healing, the growth body rate can be responsible for specific complications, such as contractures, alopecia, and scar intussusceptions. Its evolutionary character implies the need of an attentive follow-up until adult age. Psychologic repercussions, as a consequence of pathologic scars, must be prevented and investigated by the surgeon. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

[Comatose states: etiopathogenesis, experimental studies, treatment of hepatic coma].

PubMed

Strekalova, O S; Uchaĭkin, V F; Ipatova, O M; Torkhovskaia, T I; Medvedeva, N V; Storozhakov, G I; Archakov, A I

2009-01-01

The review presents the modern concepts on biochemical mechanisms of processes, that result in comatose states (CS), with emphasis on the search of new therapeutic approaches. CS of various origin causes severe suppression of brain cells functioning and stable unconsciousness. Numerous reasons of various CS are classified into two main groups: primary brain damages (ischemia, tumor, trauma) and secondary damages originating from system injuries in the body (endocrine, toxic e. c.). The most often primary CS is the hypoxic-ischemic one, as result of corresponding encephalopathy. Its mechanism is the brain cells "energy crisis"--because of decreased blood supply or its deficiency by energy substrates or/and by oxygen. Among secondary CS the substantial place takes hepatic coma as a consequence of hepatic encephalopathy in severe liver diseases--cirrhosis, acute liver failure, sharp intoxication. Its main reason is associated with exess of ammonia entering the brain tissue (it accumulates in blood because of lack of its removing by damaged hepatocytes). Ammonia reacts with glutamate in brain astrocytes and the product of this reaction, glutamine, induced osmotic imbalance, that results in change of form and functions of these important brain cells. It induces, in turn, neurons functions damages, changes in neurotransmission and cerebral blood flow and all these may give rise CS. The most of CS studies are carried out in human. Experimental models ofhepatic CS are reproduced mainly in rats, the most often by surgery methods. Other models included administration of thioacetamide or D-galactosamine, sometimes in combination with lipopolysaccharide. In earlier studies ammonia administration together with liver damages by ligation or by CCl4 was used. The main principles of hepatic coma treatment include the care of encephalopathy, detoxification, and liver treatment. Elaboration of new nanodrugs with increased penetration into tissues and cells, in particular, on the base of phospholipid nanoparticles, may increase substantially the therapeuti efficiency. One of such drug is thought to be a new hepatoprotective preparation phosphogliv--nanoparticles of soy phosphatidylcholine with glycyrrhizic acid. It is supposed, that the further development of phospholipid nanoforms, with minimal particle sizes, may reveal the more action in CS treatment.

Microsecond enamel ablation with 10.6μm CO2 laser radiation

NASA Astrophysics Data System (ADS)

Góra, W. S.; McDonald, A.; Hand, D. P.; Shephard, J. D.

2016-02-01

Lasers have been previously been used for dental applications, however there remain issues with thermally-induced cracking. In this paper we investigate the impact of pulse length on CO2 laser ablation of human dental enamel. Experiments were carried in vitro on molar teeth without any modification to the enamel surface, such as grinding or polishing. In addition to varying the pulse length, we also varied pulse energy and focal position, to determine the most efficient ablation of dental hard tissue and more importantly to minimize or eradicate cracking. The maximum temperature rise during the multi pulse ablation process was monitored using a set of thermocouples embedded into the pulpal chamber. The application of a laser device in dental surgery allows removal of tissue with higher precision, which results in minimal loss of healthy dental tissue. In this study we use an RF discharge excited CO2 laser operating at 10.6μm. The wavelength of 10.6 μm overlaps with a phosphate band (PO3-4) absorption in dental hard tissue hence the CO2 laser radiation has been selected as a potential source for modification of the tissue. This research describes an in-depth analysis of single pulse laser ablation. To determine the parameters that are best suited for the ablation of hard dental tissue without thermal cracking, a range of pulse lengths (10-200 μs), and fluences (0-100 J/cm2) are tested. In addition, different laser focusing approaches are investigated to select the most beneficial way of delivering laser radiation to the surface (divergent/convergent beam). To ensure that these processes do not increase the temperature above the critical threshold and cause the necrosis of the tissue a set of thermocouples was placed into the pulpal chambers. Intermittent laser radiation was investigated with and without application of a water spray to cool down the ablation site and the adjacent area. Results show that the temperature can be kept below the critical threshold either by using water spray or by decreasing the repetition rate. We demonstrate that CO2 laser pulses with pulse lengths in the regime of 10 μs can provide precise enamel tissue removal without introducing any unwanted thermal damage.

Proton therapy treatment monitoring with the DoPET system: activity range, positron emitters evaluation and comparison with Monte Carlo predictions

NASA Astrophysics Data System (ADS)

Muraro, S.; Battistoni, G.; Belcari, N.; Bisogni, M. G.; Camarlinghi, N.; Cristoforetti, L.; Del Guerra, A.; Ferrari, A.; Fracchiolla, F.; Morrocchi, M.; Righetto, R.; Sala, P.; Schwarz, M.; Sportelli, G.; Topi, A.; Rosso, V.

2017-12-01

Ion beam irradiations can deliver conformal dose distributions minimizing damage to healthy tissues thanks to their characteristic dose profiles. Nevertheless, the location of the Bragg peak can be affected by different sources of range uncertainties: a critical issue is the treatment verification. During the treatment delivery, nuclear interactions between the ions and the irradiated tissues generate β+ emitters: the detection of this activity signal can be used to perform the treatment monitoring if an expected activity distribution is available for comparison. Monte Carlo (MC) codes are widely used in the particle therapy community to evaluate the radiation transport and interaction with matter. In this work, FLUKA MC code was used to simulate the experimental conditions of irradiations performed at the Proton Therapy Center in Trento (IT). Several mono-energetic pencil beams were delivered on phantoms mimicking human tissues. The activity signals were acquired with a PET system (DoPET) based on two planar heads, and designed to be installed along the beam line to acquire data also during the irradiation. Different acquisitions are analyzed and compared with the MC predictions, with a special focus on validating the PET detectors response for activity range verification.

Fluorescent imaging of cancerous tissues for targeted surgery

PubMed Central

Bu, Lihong; Shen, Baozhong; Cheng, Zhen

2014-01-01

To maximize tumor excision and minimize collateral damage is the primary goal of cancer surgery. Emerging molecular imaging techniques have to “image-guided surgery” developing into “molecular imaging-guided surgery”, which is termed “targeted surgery” in this review. Consequently, the precision of surgery can be advanced from tissue-scale to molecule-scale, enabling “targeted surgery” to be a component of “targeted therapy”. Evidence from numerous experimental and clinical studies has demonstrated significant benefits of fluorescent imaging in targeted surgery with preoperative molecular diagnostic screening. Fluorescent imaging can help to improve intraoperative staging and enable more radical cytoreduction, detect obscure tumor lesions in special organs, highlight tumor margins, better map lymph node metastases, and identify important normal structures intraoperatively. Though limited tissue penetration of fluorescent imaging and tumor heterogeneity are two major hurdles for current targeted surgery, multimodality imaging and multiplex imaging may provide potential solutions to overcome these issues, respectively. Moreover, though many fluorescent imaging techniques and probes have been investigated, targeted surgery remains at a proof-of-principle stage. The impact of fluorescent imaging on cancer surgery will likely be realized through persistent interdisciplinary amalgamation of research in diverse fields. PMID:25064553

Isolation of tooth pulp cells for sex chromatin studies in experimental dehydrated and cremated remains.

PubMed

Duffy, J B; Waterfield, J D; Skinner, M F

1991-03-01

In experiments designed to assess sex chromatin in artificially mummified and heated pulp tissue, a method was devised that successfully separates cells while minimizing nuclear damage. Sex chromatin (both Barr bodies and F-bodies) is shown to preserve in dehydrated human pulps up to one year. Human pulp tissue retains sex diagnostic characteristics when heated to 100 degrees C for up to 1 h. Parallel experiments on extracted teeth from young pigs reveals comparable tissue preservation. Heat penetration is retarded, however, in unextracted pig teeth in fleshed jaws such that temperatures could be raised to 300 degrees C for longer than 1 h. Heat penetration into fleshed material was further tested by the insertion of thermocouple probes to assess the temperature attained within the pulp chamber. At chamber temperatures up to 75 degrees C sex diagnosis in human pulps from extracted teeth was still possible. In outdoor incineration of fleshed pigs' heads in an open fire, 75 degrees C in the pulp chamber was reached at a fire temperature within the range 500-700 degrees C. The implications of these findings for forensic situations are described.

Piezoelectric Bone Surgery: A Review of the Literature and Potential Applications in Veterinary Oromaxillofacial Surgery

PubMed Central

Hennet, Philippe

2015-01-01

Piezoelectric bone surgery is a recent and innovative technology, permitting a selective cut of mineralized tissue while sparing soft tissue. Similar to a dental scaler, a high frequency vibration, in the range of 25–35 kHz, is transmitted to a metallic tip. However, the power of the piezosurgical instrument is three to six times higher than that of a dental scaler. The major advantages of this technology include high precision, a design that increases ease of curvilinear osteotomy, less trauma to soft tissue, preservation of neurological and vascular structures, reduced hemorrhage, minimal thermal damage to the bone, as well as overall improvement of healing. The handpiece of the instrument is equipped with a sterile irrigation system and light-emitting diode (LED) light, which improves visibility and overall safety. Piezoelectric surgery is particularly useful when performing delicate bone procedures such as periodontal or endodontic surgery. It is also indicated when performing more invasive bone surgery such as maxillectomy, mandibulectomy, and condylectomy, where preservation of neurovascular structures is important. Piezoelectric instruments are different from rotary instrumentation or oscillating saws, they require light pressure with constant motion of the tip. Training is required to master the technique. PMID:26664937

Nasal packing and stenting

PubMed Central

Weber, Rainer K.

2011-01-01

Nasal packs are indispensable in ENT practice. This study reviews current indications, effectiveness and risks of nasal packs and stents. In endoscopic surgery, nasal packs should always have smooth surfaces to minimize mucosal damage, improve wound healing and increase patient comfort. Functional endoscopic endonasal sinus surgery allows the use of modern nasal packs, since pressure is no longer required. So called hemostatic/resorbable materials are a first step in this direction. However, they may lead to adhesions and foreign body reactions in mucosal membranes. Simple occlusion is an effective method for creating a moist milieu for improved wound healing and avoiding dryness. Stenting of the frontal sinus is recommended if surgery fails to produce a wide, physiologically shaped drainage path that is sufficiently covered by intact tissue. PMID:22073095

Periodic annealing of radiation damage in GaAs solar cells

NASA Technical Reports Server (NTRS)

Loo, R. Y.; Knechtli, R. C.; Kamath, G. S.

1980-01-01

Continuous annealing of GaAs solar cells is compared with periodic annealing to determine their relative effectiveness in minimizing proton radiation damage. It is concluded that continuous annealing of the cells in space at 150 C can effectively reduce the proton radiation damage to the GaAs solar cells. Periodic annealing is most effective if it can be initiated at relatively low fluences (approximating continuous annealing), especially if low temperatures of less than 200 C are to be used. If annealing is started only after the fluence of the damaging protons has accumulated to a high value 10 to the 11th power sq/pcm), effective annealing is still possible at relatively high temperatures. Finally, since electron radiation damage anneals even more easily than proton radiation damage, substantial improvements in GaAs solar cell life can be achieved by incorporating the proper annealing capabilities in solar panels for practical space missions where both electron and proton radiation damage have to be minimized.

High-temperature thermal treatment of the uterus

NASA Astrophysics Data System (ADS)

Ryan, Thomas P.; Xiao, Jia Hua; Chung, Juh Yun

2003-06-01

More than 200,000 hysterectomies are performed annually in the US due to abnormal uterine bleeding from excessive menstrual flow. A minimally invasive procedure has been developed using thermal treatment combined with pressure to the endometrial lining of the uterus. Results from a 3-D finite element model will be shown, as well as experimental data. Good correlation was seen between simulations and experiments. The study found similar results then temperatures were increased and times for treatment were shortened.More than 200,000 hysterectomies are performed annually in the US due to abnormal uterine bleeding from excessive menstrual flow. A minimally invasive procedure has been developed using a balloon-based thermal treatment combined with pressure to the endometrial lining of the uterus. A 3D finite element model was set up to simulate the balloon ablation device in the human uterus as used in over 150,000 patients to date. Several additional simulations were made at higher temperatures to seek alternative combinations with higher temperature and shorter time intervals for the same depth of penetration, or deeper penetration at longer times and elevated temperatures. A temperature range of 87 to 150°C was explored. The Bioheat Equation was used in the simulations to predict temperature distributions in tissue. The Damage Integral was also used to characterize the location at depth of irreversible damage in the uterus. Treatment safety issues were also analyzed as the simulations showed the depth of penetration into the myometrium, towards the serosa.

Assessing viability of extracorporeal preserved muscle transplants using external field stimulation: a novel tool to improve methods prolonging bridge-to-transplantation time

PubMed Central

Taeger, Christian D.; Friedrich, Oliver; Dragu, Adrian; Weigand, Annika; Hobe, Frieder; Drechsler, Caroline; Geppert, Carol I.; Arkudas, Andreas; Münch, Frank; Buchholz, Rainer; Pollmann, Charlotte; Schramm, Axel; Birkholz, Torsten; Horch, Raymund E.; Präbst, Konstantin

2015-01-01

Preventing ischemia-related cell damage is a priority when preserving tissue for transplantation. Perfusion protocols have been established for a variety of applications and proven to be superior to procedures used in clinical routine. Extracorporeal perfusion of muscle tissue though cumbersome is highly desirable since it is highly susceptible to ischemia-related damage. To show the efficacy of different perfusion protocols external field stimulation can be used to immediately visualize improvement or deterioration of the tissue during active and running perfusion protocols. This method has been used to show the superiority of extracorporeal perfusion using porcine rectus abdominis muscles perfused with heparinized saline solution. Perfused muscles showed statistically significant higher ability to exert force compared to nonperfused ones. These findings can be confirmed using Annexin V as marker for cell damage, perfusion of muscle tissue limits damage significantly compared to nonperfused tissue. The combination of extracorporeal perfusion and external field stimulation may improve organ conservation research. PMID:26145230

Wound ballistics of firearm-related injuries--part 1: missile characteristics and mechanisms of soft tissue wounding.

PubMed

Stefanopoulos, P K; Filippakis, K; Soupiou, O T; Pazarakiotis, V C

2014-12-01

Firearm-related injuries are caused by a wide variety of weapons and projectiles. The kinetic energy of the penetrating projectile defines its ability to disrupt and displace tissue, whereas the actual tissue damage is determined by the mode of energy release during the projectile-tissue interaction and the particular characteristics of the tissues and organs involved. Certain projectile factors, namely shape, construction, and stability, greatly influence the rate of energy transfer to the tissues along the wound track. Two zones of tissue damage can be identified, the permanent cavity created by the passage of the bullet and a potential area of contused tissue surrounding it, produced mainly by temporary cavitation which is a manifestation of effective high-energy transfer to tissue. Due to the complex nature of these injuries, wound assessment and the type and extent of treatment required should be based on an understanding of the various mechanisms contributing to tissue damage. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Tissue engineering: construction of a multicellular 3D scaffold for the delivery of layered cell sheets.

PubMed

Turner, William S; Sandhu, Nabjot; McCloskey, Kara E

2014-10-03

Many tissues, such as the adult human hearts, are unable to adequately regenerate after damage.(2,3) Strategies in tissue engineering propose innovations to assist the body in recovery and repair. For example, TE approaches may be able to attenuate heart remodeling after myocardial infarction (MI) and possibly increase total heart function to a near normal pre-MI level.(4) As with any functional tissue, successful regeneration of cardiac tissue involves the proper delivery of multiple cell types with environmental cues favoring integration and survival of the implanted cell/tissue graft. Engineered tissues should address multiple parameters including: soluble signals, cell-to-cell interactions, and matrix materials evaluated as delivery vehicles, their effects on cell survival, material strength, and facilitation of cell-to-tissue organization. Studies employing the direct injection of graft cells only ignore these essential elements.(2,5,6) A tissue design combining these ingredients has yet to be developed. Here, we present an example of integrated designs using layering of patterned cell sheets with two distinct types of biological-derived materials containing the target organ cell type and endothelial cells for enhancing new vessels formation in the "tissue". Although these studies focus on the generation of heart-like tissue, this tissue design can be applied to many organs other than heart with minimal design and material changes, and is meant to be an off-the-shelf product for regenerative therapies. The protocol contains five detailed steps. A temperature sensitive Poly(N-isopropylacrylamide) (pNIPAAM) is used to coat tissue culture dishes. Then, tissue specific cells are cultured on the surface of the coated plates/micropattern surfaces to form cell sheets with strong lateral adhesions. Thirdly, a base matrix is created for the tissue by combining porous matrix with neovascular permissive hydrogels and endothelial cells. Finally, the cell sheets are lifted from the pNIPAAM coated dishes and transferred to the base element, making the complete construct.

Coronectomy of third molar: a reduced risk technique for inferior alveolar nerve damage.

PubMed

Ahmed, Chkoura; Wafae, El Wady; Bouchra, Taleb

2011-05-01

Causing damage to the inferior alveolar nerve (IAN) when extracting lower third molars is due to the intimate relationship between the nerve and the roots of the teeth. When the proximity radiologic markers between the IAN and the root of the third molars are present, the technique of coronectomy can be proposed as an alternative to extraction to minimize the risk of nerve injury, with minimal complications. Nerve injury after the extraction of the mandibular third molar is a serious complication. The technique of coronectomy can be proposed to minimize the risk.

A minimal spatial cell lineage model of epithelium: tissue stratification and multi-stability

NASA Astrophysics Data System (ADS)

Yeh, Wei-Ting; Chen, Hsuan-Yi

2018-05-01

A minimal model which includes spatial and cell lineage dynamics for stratified epithelia is presented. The dependence of tissue steady state on cell differentiation models, cell proliferation rate, cell differentiation rate, and other parameters are studied numerically and analytically. Our minimal model shows some important features. First, we find that morphogen or mechanical stress mediated interaction is necessary to maintain a healthy stratified epithelium. Furthermore, comparing with tissues in which cell differentiation can take place only during cell division, tissues in which cell division and cell differentiation are decoupled can achieve relatively higher degree of stratification. Finally, our model also shows that in the presence of short-range interactions, it is possible for a tissue to have multiple steady states. The relation between our results and tissue morphogenesis or lesion is discussed.

Candida-streptococcal mucosal biofilms display distinct structural and virulence characteristics depending on growth conditions and hyphal morphotypes.

PubMed

Bertolini, M M; Xu, H; Sobue, T; Nobile, C J; Del Bel Cury, A A; Dongari-Bagtzoglou, A

2015-08-01

Candida albicans and streptococci of the mitis group form communities in multiple oral sites, where moisture and nutrient availability can change spatially or temporally. This study evaluated structural and virulence characteristics of Candida-streptococcal biofilms formed on moist or semidry mucosal surfaces, and tested the effects of nutrient availability and hyphal morphotype on dual-species biofilms. Three-dimensional models of the oral mucosa formed by immortalized keratinocytes on a fibroblast-embedded collagenous matrix were used. Infections were carried out using Streptococcus oralis strain 34, in combination with a C. albicans wild-type strain, or pseudohyphal-forming mutant strains. Increased moisture promoted a homogeneous surface biofilm by C. albicans. Dual biofilms had a stratified structure, with streptococci growing in close contact with the mucosa and fungi growing on the bacterial surface. Under semidry conditions, Candida formed localized foci of dense growth, which promoted focal growth of streptococci in mixed biofilms. Candida biofilm biovolume was greater under moist conditions, albeit with minimal tissue invasion, compared with semidry conditions. Supplementing the infection medium with nutrients under semidry conditions intensified growth, biofilm biovolume and tissue invasion/damage, without changing biofilm structure. Under these conditions, the pseudohyphal mutants and S. oralis formed defective superficial biofilms, with most bacteria in contact with the epithelial surface, below a pseudohyphal mass, resembling biofilms growing in a moist environment. The presence of S. oralis promoted fungal invasion and tissue damage under all conditions. We conclude that moisture, nutrient availability, hyphal morphotype and the presence of commensal bacteria influence the architecture and virulence characteristics of mucosal fungal biofilms. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

SR-TXRF analysis of trace elements in whole blood and heart of rats: effects of irradiation with low and high doses

NASA Astrophysics Data System (ADS)

Mota, C. L.; Pickler, A.; Braz, D.; Barroso, R. C.; Mantuano, A.; Salata, C.; Ferreira-Machado, S. C.; Lau, C. C.; de Almeida, C. E.

2018-04-01

In the last decades, studies showed that the exposure to low doses of ionizing radiation of the body could sense and activate the cell signaling pathways needed to respond to any induced cellular damage. This procedure reduces cell killing compared with a single dose of high radiation dose. Damage to the vasculature can affect the function of most body organs by restricting blood flow and oxygen to tissues; however, the heart and brain are of main concern. The precise relationship between long-term health effects and low-dose exposures remain poorly understood. Biological markers are powerful tools that can be used to determine dose- response relationships and to estimate risk, especially when dealing with, the effects of low dose exposures in humans. These markers should be specific, sensitive, as well as easy and fast to quantify. Various types of biologic specimens are potential candidates for identifying biomarkers but blood has the advantage of being minimally invasive to obtain. In this study, we propose to apply total reflection X-ray fluorescence to quantify possible chemical elemental concentration (sulfer, iron, zinc, potassium and calcium) changes in blood and heart tissues of Wistar rats after total body irradiation with low (0.1 Gy) and high (2.5 Gy) doses. The fluorescence measurements were carried out at the X-ray Fluorescence beamline in the Brazilian Synchrotron Light Laboratory. The results showed that the irradiated animals with low doses have significant alterations in blood and cardiac tissue when compared with animals that received high doses of radiation. Taken together the analysis of all the elements, we can observe that the radiation induced oxidative stress may be the leading cause for alteration of the elemental level in the studied samples.

pH and chloride recordings in living cells using two-photon fluorescence lifetime imaging microscopy

NASA Astrophysics Data System (ADS)

Lahn, Mattes; Hille, Carsten; Koberling, Felix; Kapusta, Peter; Dosche, Carsten

2010-02-01

Today fluorescence lifetime imaging microscopy (FLIM) has become an extremely powerful technique in life sciences. The independency of the fluorescence decay time on fluorescence dye concentration and emission intensity circumvents many artefacts arising from intensity based measurements. To minimize cell damage and improve scan depth, a combination with two-photon (2P) excitation is quite promising. Here, we describe the implementation of a 2P-FLIM setup for biological applications. For that we used a commercial fluorescence lifetime microscope system. 2P-excitation at 780nm was achieved by a non-tuneable, but inexpensive and easily manageable mode-locked fs-fiber laser. Time-resolved fluorescence image acquisition was performed by objective-scanning with the reversed time-correlated single photon counting (TCSPC) technique. We analyzed the suitability of the pH-sensitive dye BCECF and the chloride-sensitive dye MQAE for recordings in an insect tissue. Both parameters are quite important, since they affect a plethora of physiological processes in living tissues. We performed a straight forward in situ calibration method to link the fluorescence decay time with the respective ion concentration and carried out spatially resolved measurements under resting conditions. BCECF still offered only a limited dynamic range regarding fluorescence decay time changes under physiologically pH values. However, MQAE proofed to be well suited to record chloride concentrations in the physiologically relevant range. Subsequently, several chloride transport pathways underlying the intracellular chloride homeostasis were investigated pharmacologically. In conclusion, 2P-FLIM is well suited for ion detection in living tissues due to precise and reproducible decay time measurements in combination with reduced cell and dye damages.

The role of tactile feedback in grip force during laparoscopic training tasks.

PubMed

Wottawa, Christopher R; Cohen, Jeremiah R; Fan, Richard E; Bisley, James W; Culjat, Martin O; Grundfest, Warren S; Dutson, Erik P

2013-04-01

Laparoscopic minimally invasive surgery has revolutionized surgical care by reducing trauma to the patient, thereby decreasing the need for medication and shortening recovery times. During open procedures, surgeons can directly feel tissue characteristics. However, in laparoscopic surgery, tactile feedback during grip is attenuated and limited to the resistance felt in the tool handle. Excessive grip force during laparoscopic surgery can lead to tissue damage. Providing additional supplementary tactile feedback may allow subjects to have better control of grip force and identification of tissue characteristics, potentially decreasing the learning curve associated with complex minimally invasive techniques. A tactile feedback system has been developed and integrated into a modified laparoscopic grasper that allows forces applied at the grasper tips to be felt by the surgeon's hands. In this study, 15 subjects (11 novices, 4 experts) were asked to perform single-handed peg transfers using these laparoscopic graspers in three trials (feedback OFF, ON, OFF). Peak and average grip forces (newtons) during each grip event were measured and compared using a Wilcoxon ranked test in which each subject served as his or her own control. After activating the tactile feedback system, the novice subject population showed significant decreases in grip force (p < 0.003). When the system was deactivated for the third trial, there were significant increases in grip force (p < 0.003). Expert subjects showed no significant improvements with the addition of tactile feedback (p > 0.05 in all cases). Supplementary tactile feedback helped novice subjects reduce grip force during the laparoscopic training task but did not offer improvements for the four expert subjects. This indicates that tactile feedback may be beneficial for laparoscopic training but has limited long-term use in the nonrobotic setting.

Effects of tissue mechanical properties on susceptibility to histotripsy-induced tissue damage

NASA Astrophysics Data System (ADS)

Vlaisavljevich, Eli; Kim, Yohan; Owens, Gabe; Roberts, William; Cain, Charles; Xu, Zhen

2014-01-01

Histotripsy is a non-invasive tissue ablation method capable of fractionating tissue by controlling acoustic cavitation. To determine the fractionation susceptibility of various tissues, we investigated histotripsy-induced damage on tissue phantoms and ex vivo tissues with different mechanical strengths. A histotripsy bubble cloud was formed at tissue phantom surfaces using 5-cycle long ultrasound pulses with peak negative pressure of 18 MPa and PRFs of 10, 100, and 1000 Hz. Results showed significantly smaller lesions were generated in tissue phantoms of higher mechanical strength. Histotripsy was also applied to 43 different ex vivo porcine tissues with a wide range of mechanical properties. Gross morphology demonstrated stronger tissues with higher ultimate stress, higher density, and lower water content were more resistant to histotripsy damage in comparison to weaker tissues. Based on these results, a self-limiting vessel-sparing treatment strategy was developed in an attempt to preserve major vessels while fractionating the surrounding target tissue. This strategy was tested in porcine liver in vivo. After treatment, major hepatic blood vessels and bile ducts remained intact within a completely fractionated liver volume. These results identify varying susceptibilities of tissues to histotripsy therapy and provide a rational basis to optimize histotripsy parameters for treatment of specific tissues.

Influence of unit operations on the levels of polyacetylenes in minimally processed carrots and parsnips: An industrial trial.

PubMed

Koidis, Anastasios; Rawson, Ashish; Tuohy, Maria; Brunton, Nigel

2012-06-01

Carrots and parsnips are often consumed as minimally processed ready-to-eat convenient foods and contain in minor quantities, bioactive aliphatic C17-polyacetylenes (falcarinol, falcarindiol, falcarindiol-3-acetate). Their retention during minimal processing in an industrial trial was evaluated. Carrot and parsnips were prepared in four different forms (disc cutting, baton cutting, cubing and shredding) and samples were taken in every point of their processing line. The unit operations were: peeling, cutting and washing with chlorinated water and also retention during 7days storage was evaluated. The results showed that the initial unit operations (mainly peeling) influence the polyacetylene retention. This was attributed to the high polyacetylene content of their peels. In most cases, when washing was performed after cutting, less retention was observed possibly due to leakage during tissue damage occurred in the cutting step. The relatively high retention during storage indicates high plant matrix stability. Comparing the behaviour of polyacetylenes in the two vegetables during storage, the results showed that they were slightly more retained in parsnips than in carrots. Unit operations and especially abrasive peeling might need further optimisation to make them gentler and minimise bioactive losses. Copyright © 2011 Elsevier Ltd. All rights reserved.

[Scanning electron microscopy of heat-damaged bone tissue].

PubMed

Harsanyl, L

1977-02-01

Parts of diaphyses of bones were exposed to high temperature of 200-1300 degrees C. Damage to the bone tissue caused by the heat was investigated. The scanning electron microscopic picture seems to be characteristic of the temperature applied. When the bones heated to the high temperature of 700 degrees C characteristic changes appear on the periostal surface, higher temperatura on the other hand causes damage to the compact bone tissue and can be observed on the fracture-surface. Author stresses the importance of this technique in the legal medicine and anthropology.

Neurosurgical patties: adhesion and damage mitigation.

PubMed

Stratton-Powell, Ashley A; Anderson, Ian A; Timothy, Jake; Kapur, Nikil; Culmer, Peter

2015-07-01

Neurosurgical patties are textile pads used during most neurosurgical operations to protect tissues, manage the fluid environment, control hemostasis, and aid tissue manipulation. Recent research has suggested that, contrary to their aim, patties adhere to brain tissue and cause damage during removal. This study aimed to characterize and quantify the degree of and consequences resulting from adhesion between neurosurgical patties and brain tissue. Using a customized peel apparatus, the authors performed 90° peel tests on 5 patty products: Policot, Telfa, Americot, Delicot, and Ray-Cot (n = 247) from American Surgical Company. They tested 4 conditions: wet patty on glass (control), wet patty on wet brain peeled at 5 mm/sec (wet), dry patty on wet brain peeled at 5 mm/sec (dry), and wet patty on wet brain peeled at 20 mm/sec (speed). The interaction between patty and tissue was analyzed using peel-force traces and pre-peel histological analysis. Adhesion strength differed between patty products (p < 0.001) and conditions (p < 0.001). Adhesion strength was greatest for Delicot patties under wet (2.22 mN/mm) and dry (9.88 mN/mm) conditions. For all patties, damage at the patty-tissue interface was proportional to the degree of fiber contact. When patties were irrigated, mechanical adhesion was reduced by up to 550% compared with dry usage. For all patty products, mechanical (destructive) and liquid-mediated (nondestructive) adhesion caused damage to neural tissue. The greatest adhesion occurred with Delicot patties. To mitigate patty adhesion and neural tissue damage, surgeons should consider regular irrigation to be essential during neurosurgical procedures.

Optical monitoring of spinal cord subcellular damage after acute spinal cord injury

NASA Astrophysics Data System (ADS)

Shadgan, Babak; Manouchehri, Neda; So, Kitty; Shortt, Katelyn; Fong, Allan; Streijger, Femke; Macnab, Andrew; Kwon, Brian K.

2018-02-01

Introduction: Sudden physical trauma to the spinal cord results in acute spinal cord injury (SCI), leading to spinal cord (SC) tissue destruction, acute inflammation, increased SC intraparenchymal pressure, and tissue ischemia, hypoxia, and cellular necrosis. The ability to monitor SC tissue viability at subcellular level, using a real-time noninvasive method, would be extremely valuable to clinicians for estimating acute SCI damage, and adjusting and monitoring treatment in the intensive care setting. This study examined the feasibility and sensitivity of a custommade near infrared spectroscopy (NIRS) sensor to monitor the oxidation state of SC mitochondrial cytochrome aa3 (CCO), which reflects the subcellular damage of SC tissue in an animal model of SCI. Methods: Six anesthetized Yorkshire pigs were studied using a custom-made multi-wavelength NIRS system with a miniaturized optical sensor applied directly on the surgically exposed SC at T9. The oxidation states of SC tissue hemoglobin and CCO were monitored before, during and after acute SCI, and during mean arterial pressure alterations. Results: Non-invasive NIRS monitoring reflected changes in SC tissue CCO, simultaneous but independent of changes in hemoglobin saturation following acute SCI. A consistent decrease in SC tissue CCO chromophore concentration (-1.98 +/- 2.1 ab, p<0.05) was observed following SCI, indicating progressive SC cellular damage at the injury site. Elevation of mean arterial pressure can reduce SC tissue damage as suggested by different researchers and observed by significant increase in SC tissue CCO concentration (1.51 +/- 1.7 ab, p<0.05) in this study. Conclusions: This pilot study indicates that a novel miniaturized multi-wave NIRS sensor has the potential to monitor post-SCI changes of SC cytochrome aa3 oxygenation state in real time. Further development of this method may offer new options for improved SCI care.

In vivo evaluation of needle force and friction stress during insertion at varying insertion speed into the brain.

PubMed

Casanova, Fernando; Carney, Paul R; Sarntinoranont, Malisa

2014-11-30

Convection enhanced delivery (CED) infuses drugs directly into brain tissue. Needle insertion is required and results in tissue damage which can promote flowback along the needle track and improper targeting. The goal of this study was to evaluate friction stress (calculated from needle insertion force) as a measure of tissue contact and damage during needle insertion for varying insertion speeds. Forces and surface dimpling during needle insertion were measured in rat brain in vivo. Needle retraction forces were used to calculate friction stresses. These measures were compared to track damage from a previous study. Differences between brain tissues and soft hydrogels were evaluated for varying insertion speeds: 0.2, 2, and 10mm/s. In brain tissue, average insertion force and surface dimpling increased with increasing insertion speed. Average friction stress along the needle-tissue interface decreased with insertion speed (from 0.58 ± 0.27 to 0.16 ± 0.08 kPa). Friction stress varied between brain regions: cortex (0.227 ± 0.27 kPa), external capsule (0.222 ± 0.19 kPa), and CPu (0.383 ± 0.30 kPa). Hydrogels exhibited opposite trends for dimpling and friction stress with insertion speed. Previously, increasing needle damage with insertion speed has been measured with histological methods. Friction stress appears to decrease with increasing tissue damage and decreasing tissue contact, providing the potential for in vivo and real time evaluation along the needle track. Force derived friction stress decreased with increasing insertion speed and was smaller within white matter regions. Hydrogels exhibited opposite trends to brain tissue. Copyright © 2014 Elsevier B.V. All rights reserved.

The TopClosure® 3S System, for skin stretching and a secure wound closure.

PubMed

Topaz, Moris; Carmel, Narin-Nard; Silberman, Adi; Li, Ming Sen; Li, Yong Zhong

2012-07-01

The principle of stretching wound margins for primary wound closure is commonly practiced and used for various skin defects, leading at times to excessive tension and complications during wound closure. Different surgical techniques, skin stretching devices and tissue expanders have been utilized to address this issue. Previously designed skin stretching devices resulted in considerable morbidity. They were invasive by nature and associated with relatively high localized tissue pressure, frequently leading to necrosis, damage and tearing of skin at the wound margins. To assess the clinical effectiveness and performance and, to determine the safety of TopClosure® for gradual, controlled, temporary, noninvasive and invasive applications for skin stretching and secure wound closing, the TopClosure® device was applied to 20 patients for preoperative skin lesion removal and to secure closure of a variety of wound sizes. TopClosure® was reinforced with adhesives, staples and/or surgical sutures, depending on the circumstances of the wound and the surgeon's judgment. TopClosure® was used prior to, during and/or after surgery to reduce tension across wound edges. No significant complications or adverse events were associated with its use. TopClosure® was effectively used for preoperative skin expansion in preparation for dermal resection (e.g., congenital nevi). It aided closure of large wounds involving significant loss of skin and soft tissue by mobilizing skin and subcutaneous tissue, thus avoiding the need for skin grafts or flaps. Following surgery, it was used to secure closure of wounds under tension, thus improving wound aesthetics. A sample case study will be presented. We designed TopClosure®, an innovative device, to modify the currently practiced concept of wound closure by applying minimal stress to the skin, away from damaged wound edges, with flexible force vectors and versatile methods of attachment to the skin, in a noninvasive or invasive manner.

Histopathology Image Analysis in Two Long-Term Animal Experiments with Helical Flow Total Artificial Heart.

PubMed

Wotke, Jiri; Homolka, Pavel; Vasku, Jaromír; Dobsak, Petr; Palanova, Petra; Mrkvicova, Veronika; Konecny, Petr; Soska, Vladimir; Pohanka, Michal; Novakova, Marie; Yurimoto, Terumi; Saito, Itsuro; Inoue, Yusuke; Isoyama, Takashi; Abe, Yusuke

2016-12-01

Histopathological analysis can provide important information in long-term experiments with total artificial heart (TAH). Recently, a new type of blood pump, the helical flow total artificial heart (HF-TAH) was developed. This study aimed to investigate the changes in selected vital organs in animal experiments with implanted HF-TAH. Samples from lung, liver, and kidneys from two female goats (No. 1301 and No. 1304) with implanted HF-TAH were analyzed. Tissue samples were fixed in 10% formaldehyde and 4 µm thick transverse sections were stained with hematoxylin-eosin (HE). Additional staining was done for detection of connective tissue (Masson-Goldner stain) and for detection of iron (hemosiderin) deposits (Perls stain). Sections were scanned at 100× and 500× magnification with a light microscope. Experiment no. 1301 survived 100 days (cause of termination was heavy damage of the right pump); experimental goat no.1304 survived 68 days and was sacrificed due to severe right hydrodynamic bearing malfunction. Histopathological analysis of liver samples proved signs of chronic venostasis with limited focal necrotic zones. Dilated tubules, proteinaceous material in tubular lumen, and hemosiderin deposits were detected in kidney samples. Contamination of the organs by embolized micro-particles was suspected at the autopsy after discovery of visible damage (scratches) of the pump impeller surface (made from titanium alloy) in both experiments. Sporadic deposits of foreign micro-particles (presumably titanium) were observed in most of the analyzed parenchymal organs. However, the described deposits were not in direct connection with inflammatory reactions in the analyzed tissues. Histopathological analysis showed the presence of minimal contamination of the lung, kidney, and liver tissue samples by foreign material (titanium very likely). The analysis showed only limited pathological changes, especially in liver and kidneys, which might be attributed to the influence of artificial perfusion often observed in chronic TAH experiments. © 2016 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

Controlled-Release Personal Use Arthropod Repellent Formulation. Phase 2

DTIC Science & Technology

1986-09-15

damage, pitting M - Hypopyon N - Corneal neovascularization P - Pannus R - Unable to visualize due to severe opacity S - Granulation scar tissue POS...M - Hypopyon N - Corneal neovascularization P - Pannus R - Unable to visualize due to severe opacity S - Granulation scar tissue POS -Positive...Corneal epithelial damage, piling L - Corneal epithelial damage, pitting M - Hypopyon N - Corneal neovascularization P - Pannus R - Unable to

Validity of reciprocity rule on mouse skin thermal damage due to CO2 laser irradiation

NASA Astrophysics Data System (ADS)

Parvin, P.; Dehghanpour, H. R.; Moghadam, M. S.; Daneshafrooz, V.

2013-07-01

CO2 laser (10.6 μm) is a well-known infrared coherent light source as a tool in surgery. At this wavelength there is a high absorbance coefficient (860 cm-1), because of vibration mode resonance of H2O molecules. Therefore, the majority of the irradiation energy is absorbed in the tissue and the temperature of the tissue rises as a function of power density and laser exposure duration. In this work, the tissue damage caused by CO2 laser (1-10 W, ˜40-400 W cm-2, 0.1-6 s) was measured using 30 mouse skin samples. Skin damage assessment was based on measurements of the depth of cut, mean diameter of the crater and the carbonized layer. The results show that tissue damage as assessed above parameters increased with laser fluence and saturated at 1000 J cm-2. Moreover, the damage effect due to high power density at short duration was not equivalent to that with low power density at longer irradiation time even though the energy delivered was identical. These results indicate the lack of validity of reciprocity (Bunsen-Roscoe) rule for the thermal damage.

Tissue damage negatively regulates LPS-induced macrophage necroptosis.

PubMed

Li, Z; Scott, M J; Fan, E K; Li, Y; Liu, J; Xiao, G; Li, S; Billiar, T R; Wilson, M A; Jiang, Y; Fan, J

2016-09-01

Infection is a common clinical complication following tissue damage resulting from surgery and severe trauma. Studies have suggested that cell pre-activation by antecedent trauma/tissue damage profoundly impacts the response of innate immune cells to a secondary infectious stimulus. Cell necroptosis, a form of regulated inflammatory cell death, is one of the mechanisms that control cell release of inflammatory mediators from important innate immune executive cells such as macrophages (Mφ), which critically regulate the progress of inflammation. In this study, we investigated the mechanism and role of trauma/tissue damage in the regulation of LPS-induced Mφ necroptosis using a mouse model simulating long-bone fracture. We demonstrate that LPS acting through Toll-like receptor (TLR) 4 promotes Mφ necroptosis. However, necroptosis is ameliorated by high-mobility group box 1 (HMGB1) release from damaged tissue. We show that HMGB1 acting through cell surface receptor for advanced glycation end products (RAGE) upregulates caveolin-1 expression, which in turn induces caveolae-mediated TLR4 internalization and desensitization to decrease Mφ necroptosis. We further show that RAGE-MyD88 activation of Cdc42 and subsequent activation of transcription factor Sp1 serves as a mechanism underlying caveolin-1 transcriptional upregulation. These results reveal a previous unidentified protective role of damage-associated molecular pattern (DAMP) molecules in restricting inflammation in response to exogenous pathogen-associated molecular pattern molecules.

Tissue damage negatively regulates LPS-induced macrophage necroptosis

PubMed Central

Li, Z; Scott, M J; Fan, E K; Li, Y; Liu, J; Xiao, G; Li, S; Billiar, T R; Wilson, M A; Jiang, Y; Fan, J

2016-01-01

Infection is a common clinical complication following tissue damage resulting from surgery and severe trauma. Studies have suggested that cell pre-activation by antecedent trauma/tissue damage profoundly impacts the response of innate immune cells to a secondary infectious stimulus. Cell necroptosis, a form of regulated inflammatory cell death, is one of the mechanisms that control cell release of inflammatory mediators from important innate immune executive cells such as macrophages (Mφ), which critically regulate the progress of inflammation. In this study, we investigated the mechanism and role of trauma/tissue damage in the regulation of LPS-induced Mφ necroptosis using a mouse model simulating long-bone fracture. We demonstrate that LPS acting through Toll-like receptor (TLR) 4 promotes Mφ necroptosis. However, necroptosis is ameliorated by high-mobility group box 1 (HMGB1) release from damaged tissue. We show that HMGB1 acting through cell surface receptor for advanced glycation end products (RAGE) upregulates caveolin-1 expression, which in turn induces caveolae-mediated TLR4 internalization and desensitization to decrease Mφ necroptosis. We further show that RAGE-MyD88 activation of Cdc42 and subsequent activation of transcription factor Sp1 serves as a mechanism underlying caveolin-1 transcriptional upregulation. These results reveal a previous unidentified protective role of damage-associated molecular pattern (DAMP) molecules in restricting inflammation in response to exogenous pathogen-associated molecular pattern molecules. PMID:26943325

Tissue damage-induced intestinal stem cell division in Drosophila

PubMed Central

Amcheslavsky, Alla; Jiang, Jin; Ip, Y. Tony

2009-01-01

SUMMARY Stem cell division is essential for tissue integrity during growth, aging, and pathogenic assaults. Adult gastrointestinal tract encounters numerous stimulations and impaired tissue regeneration may lead to inflammatory diseases and cancer. Intestinal stem cells in adult Drosophila have recently been identified and shown to replenish the various cell types within the midgut. However, it is not known whether these intestinal stem cells can respond to environmental challenges. By feeding dextran sulfate sodium and bleomycin to flies and by expressing apoptotic proteins, we show that Drosophila intestinal stem cells can increase the rate of division in response to tissue damage. Moreover, if tissue damage results in epithelial cell loss, the newly formed enteroblasts can differentiate into mature epithelial cells. By using this newly established system of intestinal stem cell proliferation and tissue regeneration, we find that the insulin receptor signaling pathway is required for intestinal stem cell division. PMID:19128792

Biochemical and pharmacological characterization of Trimersurus malabaricus snake venom.

PubMed

Gowda, Raghavendra; Rajaiah, Rajesh; Angaswamy, Nataraj; Krishna, Sharath; Bannikuppe Sannanayak, Vishwanath

2018-07-01

Trimeresurus malabaricus is a venomous pit viper species endemic to southwestern part of India. In earlier reports, we have shown that envenomation by T. malabaricus venom leading to strong local tissue damage but the mechanism of action is not clearly revealed. Local tissue damage affected by T. malabaricus venom is of great importance since the poison has serious systemic effects including death in the case of multiple attacks. The present study details the major manifestations of T. malabaricus venom and the induction of local tissue damage, which suggests that most toxins are present in the form of hydrolytic enzymes. Hydrolytic activity of the enzymes was measured and the data indicated that protease and phospholipase A 2 activity was high which is responsible for local tissue damage. Furthermore, the role of hydrolytic enzymes in the induction of pathological events such as hemorrhage, edema, myotoxicity, and blood coagulation examination were assessed through animal models. © 2018 Wiley Periodicals, Inc.

Low doses of ionizing radiation to mammalian cells may rather control than cause DNA damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feinendegen, L.E.; Bond, V.P.; Sondhaus, C.A.

This report examines the origin of tissue effects that may follow from different cellular responses to low-dose irradiation, using published data. Two principal categories of cellular responses are considered. One response category relates to the probability of radiation-induced DNA damage. The other category consists of low-dose induced metabolic changes that induce mechanisms of DNA damage mitigation, which do not operate at high levels of exposure. Modeled in this way, tissue is treated as a complex adaptive system. The interaction of the various cellular responses results in a net tissue dose-effect relation that is likely to deviate from linearity in themore » low-dose region. This suggests that the LNT hypothesis should be reexamined. This paper aims at demonstrating tissue effects as an expression of cellular responses, both damaging and defensive, in relation to the energy deposited in cell mass, by use of microdosimetric concepts.« less

Kinetics of a Collagen-Like Polypeptide Fragmentation after Mid-IR Free-Electron Laser Ablation

PubMed Central

Zavalin, Andrey; Hachey, David L.; Sundaramoorthy, Munirathinam; Banerjee, Surajit; Morgan, Steven; Feldman, Leonard; Tolk, Norman; Piston, David W.

2008-01-01

Tissue ablation with mid-infrared irradiation tuned to collagen vibrational modes results in minimal collateral damage. The hypothesis for this effect includes selective scission of protein molecules and excitation of surrounding water molecules, with the scission process currently favored. In this article, we describe the postablation infrared spectral decay kinetics in a model collagen-like peptide (Pro-Pro-Gly)10. We find that the decay is exponential with different decay times for other, simpler dipeptides. Furthermore, we find that collagen-like polypeptides, such as (Pro-Pro-Gly)10, show multiple decay times, indicating multiple scission locations and cross-linking to form longer chain molecules. In combination with data from high-resolution mass spectrometry, we interpret these products to result from the generation of reactive intermediates, such as free radicals, cyanate ions, and isocyanic acid, which can form cross-links and protein adducts. Our results lead to a more complete explanation of the reduced collateral damage resulting from infrared laser irradiation through a mechanism involving cross-linking in which collagen-like molecules form a network of cross-linked fibers. PMID:18441025

14 CFR 25.1707 - System separation: EWIS.

Code of Federal Regulations, 2013 CFR

2013-01-01

... installed to ensure adequate physical separation and electrical isolation so that damage to circuits... ensure adequate physical separation and electrical isolation so that a fault in any one airplane power... minimize potential for abrasion/chafing, vibration damage, and other types of mechanical damage. ...

14 CFR 25.1707 - System separation: EWIS.

Code of Federal Regulations, 2014 CFR

2014-01-01

... installed to ensure adequate physical separation and electrical isolation so that damage to circuits... ensure adequate physical separation and electrical isolation so that a fault in any one airplane power... minimize potential for abrasion/chafing, vibration damage, and other types of mechanical damage. ...

14 CFR 25.1707 - System separation: EWIS.

Code of Federal Regulations, 2010 CFR

2010-01-01

... installed to ensure adequate physical separation and electrical isolation so that damage to circuits... ensure adequate physical separation and electrical isolation so that a fault in any one airplane power... minimize potential for abrasion/chafing, vibration damage, and other types of mechanical damage. ...

14 CFR 25.1707 - System separation: EWIS.

Code of Federal Regulations, 2012 CFR

2012-01-01

... installed to ensure adequate physical separation and electrical isolation so that damage to circuits... ensure adequate physical separation and electrical isolation so that a fault in any one airplane power... minimize potential for abrasion/chafing, vibration damage, and other types of mechanical damage. ...

14 CFR 25.1707 - System separation: EWIS.

Code of Federal Regulations, 2011 CFR

2011-01-01

... installed to ensure adequate physical separation and electrical isolation so that damage to circuits... ensure adequate physical separation and electrical isolation so that a fault in any one airplane power... minimize potential for abrasion/chafing, vibration damage, and other types of mechanical damage. ...

The relation of microdamage to fracture and material property degradation in human cortical bone tissue

NASA Astrophysics Data System (ADS)

Akkus, Ozan

This dissertation investigates the relation of microdamage to fracture and material property degradation of human cortical bone tissue. Fracture resistance and fatigue crack growth of microcracks were examined experimentally and material property degradation was examined through theoretical modeling. To investigate the contribution of microdamage to static fracture resistance, fracture toughness tests were conducted in the transverse and longitudinal directions to the osteonal orientation of normal bone tissue. Damage accumulation was monitored by acoustic emission during testing and was spatially observed by histological observation following testing. The results suggested that the propagation of the main crack involved weakening of the tissue by diffuse damage at the fracture plane and by formation of linear microcracks away from the fracture plane for the transverse specimens. For the longitudinal specimens, growth of the main crack occurred in the form of separations at lamellar interfaces. Acoustic emission results supported the histological observations. To investigate the contribution of ultrastructure to static fracture resistance, fracture toughness tests were conducted after altering the collagen phase of the bone tissue by gamma radiation. A significant decrease in the fracture toughness, Work-to-Fracture and the amount damage was observed due to irradiation in both crack growth directions. For cortical bone irradiated at 27.5kGy, fracture toughness is reduced due to the inhibition of damage formation at and near the crack tip. Microcrack fatigue crack growth and arrest were investigated through observations of surface cracks during cyclic loading. At the applied cyclic stresses, the microcracks propagated and arrested in less than 10,000 cycles. In addition, the microcracks were observed not to grow beyond a length of 150mum and a DeltaK of 0.5MNm-3/2, supporting a microstructural barrier concept. Finally, the contribution of linear microcracks to material property degradation was examined by developing a theoretical micromechanical damage model. The model was compared to experimentally induced damage in bone tissue. The percent contribution of linear microcracks to the total degradation was predicted to be less than 5%, indicating that diffuse damage or an unidentified form of damage is primarily responsible for material property degradation in human cortical bone tissue.

Damage threshold in adult rabbit eyes after scleral cross-linking by riboflavin/blue light application.

PubMed

Iseli, Hans Peter; Körber, Nicole; Karl, Anett; Koch, Christian; Schuldt, Carsten; Penk, Anja; Liu, Qing; Huster, Daniel; Käs, Josef; Reichenbach, Andreas; Wiedemann, Peter; Francke, Mike

2015-10-01

Several scleral cross-linking (SXL) methods were suggested to increase the biomechanical stiffness of scleral tissue and therefore, to inhibit axial eye elongation in progressive myopia. In addition to scleral cross-linking and biomechanical effects caused by riboflavin and light irradiation such a treatment might induce tissue damage, dependent on the light intensity used. Therefore, we characterized the damage threshold and mechanical stiffening effect in rabbit eyes after application of riboflavin combined with various blue light intensities. Adult pigmented and albino rabbits were treated with riboflavin (0.5 %) and varying blue light (450 ± 50 nm) dosages from 18 to 780 J/cm(2) (15 to 650 mW/cm(2) for 20 min). Scleral, choroidal and retinal tissue alterations were detected by means of light microscopy, electron microscopy and immunohistochemistry. Biomechanical changes were measured by shear rheology. Blue light dosages of 480 J/cm(2) (400 mW/cm(2)) and beyond induced pathological changes in ocular tissues; the damage threshold was defined by the light intensities which induced cellular degeneration and/or massive collagen structure changes. At such high dosages, we observed alterations of the collagen structure in scleral tissue, as well as pigment aggregation, internal hemorrhages, and collapsed blood vessels. Additionally, photoreceptor degenerations associated with microglia activation and macroglia cell reactivity in the retina were detected. These pathological alterations were locally restricted to the treated areas. Pigmentation of rabbit eyes did not change the damage threshold after a treatment with riboflavin and blue light but seems to influence the vulnerability for blue light irradiations. Increased biomechanical stiffness of scleral tissue could be achieved with blue light intensities below the characterized damage threshold. We conclude that riboflavin and blue light application increased the biomechanical stiffness of scleral tissue at blue light energy levels below the damage threshold. Therefore, applied blue light intensities below the characterized damage threshold might define a therapeutic blue light tolerance range. Copyright © 2015 Elsevier Ltd. All rights reserved.

Infrared laser damage thresholds in corneal tissue phantoms using femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Boretsky, Adam R.; Clary, Joseph E.; Noojin, Gary D.; Rockwell, Benjamin A.

2018-02-01

Ultrafast lasers have become a fixture in many biomedical, industrial, telecommunications, and defense applications in recent years. These sources are capable of generating extremely high peak power that can cause laser-induced tissue breakdown through the formation of a plasma upon exposure. Despite the increasing prevalence of such lasers, current safety standards (ANSI Z136.1-2014) do not include maximum permissible exposure (MPE) values for the cornea with pulse durations less than one nanosecond. This study was designed to measure damage thresholds in corneal tissue phantoms in the near-infrared and mid-infrared to identify the wavelength dependence of laser damage thresholds from 1200-2500 nm. A high-energy regenerative amplifier and optical parametric amplifier outputting 100 femtosecond pulses with pulse energies up to 2 mJ were used to perform exposures and determine damage thresholds in transparent collagen gel tissue phantoms. Three-dimensional imaging, primarily optical coherence tomography, was used to evaluate tissue phantoms following exposure to determine ablation characteristics at the surface and within the bulk material. The determination of laser damage thresholds in the near-IR and mid-IR for ultrafast lasers will help to guide safety standards and establish the appropriate MPE levels for exposure sensitive ocular tissue such as the cornea. These data will help promote the safe use of ultrafast lasers for a wide range of applications.

CFTR expression and organ damage in cystic fibrosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tizzano, E.; Chitayat, D.; Buchwald, M.

1994-09-01

To assist our understanding of the origin of organ damage caused by cystic fibrosis (CF) disease, we have analyzed the pattern of expression of the CF gene (CFTR). mRNA in situ hybridization analysis was carried out in human fetal, newborn, infant and adult tissues and the abundance of the mRNA was correlated with the known pathology at the various stages of human development. Analysis of the pattern of expression indicates a constitutive level of mRNA in gastrointestinal tissues starting during early development and maintained throughout life. Prenatal respiratory tissues show qualitative and quantitative major differences in comparison to postnatal lungmore » samples. Male reproductive tissues show high levels of expression in the head of the epididymis compared with the rest of the male ducts. Female reproductive tissues show a variable pattern of expression at different stages during fetal development and during puberty probably due to changes in hormonal levels. Gastrointestinal and male reproductive tissues have a consistent pathology at birth, whereas no lung abnormalities have been described in newborns affected by CF. Our results show that there is no exact correlations between organ damage present at birth and the degree of CFTR expression. To explain these observations, we hypothesize that the pathogenesis of organ damage in CF depend on at least three factors: the rate of CFTR-mediated fluid secretion, differences in genotype and environmental factors, such as the amount of macromolecules in the lumen of the ducts. This last element predicts that damage will occur in tissues with high protein loads and low flow rates (e.g. pancreas, epididymis), where the absence of CFTR function leads to obstruction and pathology. Organs that express CFTR but with no significant damage (e.g. prenatal lung, female reproductive tissues), will have a low protein load and a high flow rates.« less

Mathematical modelling of blood-brain barrier failure and edema

NASA Astrophysics Data System (ADS)

Waters, Sarah; Lang, Georgina; Vella, Dominic; Goriely, Alain

2015-11-01

Injuries such as traumatic brain injury and stroke can result in increased blood-brain barrier permeability. This increase may lead to water accumulation in the brain tissue resulting in vasogenic edema. Although the initial injury may be localised, the resulting edema causes mechanical damage and compression of the vasculature beyond the original injury site. We employ a biphasic mixture model to investigate the consequences of blood-brain barrier permeability changes within a region of brain tissue and the onset of vasogenic edema. We find that such localised changes can indeed result in brain tissue swelling and that the type of damage that results (stress damage or strain damage) depends on the ability of the brain to clear edema fluid.

Mitigation of the consequence of seismically induced damage on a utility water network by means of next generation SCADA

NASA Astrophysics Data System (ADS)

Robertson, Jamie; Shinozuka, Masanobu; Wu, Felix

2011-04-01

When a lifeline system such as a water delivery network is damaged due to a severe earthquake, it is critical to identify its location and extent of the damage in real time in order to minimize the potentially disastrous consequence such damage could otherwise entail. This paper demonstrates how the degree of such minimization can be estimated qualitatively by using the water delivery system of Irvine Water Ranch District (IRWD) as testbed, when it is subjected to magnitude 6.6 San Joaquin Hills Earthquake. In this demonstration, we consider two cases when the IRWD system is equipped or not equipped with a next generation SCADA which consists of a network of MEMS acceleration sensors densely populated and optimally located. These sensors are capable of identifying the location and extent of the damage as well as transmitting the data to the SCADA center for monitoring and control.

Unresolved issues in the understanding of the pathogenesis of local tissue damage induced by snake venoms.

PubMed

Gutiérrez, José María; Rucavado, Alexandra; Escalante, Teresa; Herrera, Cristina; Fernández, Julián; Lomonte, Bruno; Fox, Jay W

2018-06-15

Snakebite envenoming by viperid species, and by some elapids, is characterized by a complex pattern of tissue damage at the anatomical site of venom injection. In severe cases, tissue destruction may be so extensive as to lead to permanent sequelae, with serious pathophysiological, social and psychological consequences. Significant advances have been performed in the study of venom-induced tissue damage, including identification and characterization of the toxins involved, insights into the mechanisms of action of venoms and toxins, and study of tissue responses to venom-induced injury. Nevertheless, much remains to be known and understood on the pathogenesis of these alterations. This review focuses on some of the pending issues in the topic of snake venom-induced local tissue damage. The traditional 'reductionist' approach, which has predominated in the study of snake venoms and their actions, needs to be complemented by more integrative and holistic perspectives aimed at capturing the complexity of these pathological alterations. Future advances in the study of these topics will certainly pave the way for innovative therapeutic interventions, with the goal of reducing the impact of this aspect of snakebite envenoming. Copyright © 2018 Elsevier Ltd. All rights reserved.

Using electrolyte leakage tests to determine lifting windows and detect tissue damage

Treesearch

Richard W. Tinus

2002-01-01

Physiological testing is rapidly coming into use as a means to determine the condition of nursery stock and predict how it will respond to treatment or use. One such test, the electrolyte leakage test, can be used to measure cold hardiness and detect tissue damage. The principle of this test is that when cell membranes are damaged, electrolytes leak out into the water...

Characterization of fatigue behavior of 2-D woven fabric reinforced ceramic matrix composite at elevated temperature. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Groner, D.J.

This study investigated the fatigue behavior and associated damage mechanisms in notched and unnotched enhanced SiC/SiC ceramic matrix composite specimens at 1100 deg C. Stiffness degradation, strain variation, and hysteresis were evaluated to characterize material behavior. Microscopic examination was performed to characterize damage mechanisms. During high cycle/low stress fatigue tests, far less fiber/matrix interface debond was evident than in low cycle/high stress fatigue tests. Notched specimens exhibited minimal stress concentration during monotonic tensile testing and minimal notch sensitivity during fatigue testing. Damage mechanisms were also similar to unnotched.

Histology and ultrastructure of picosecond laser intrastromal photorefractive keratectomy (ISPRK)

NASA Astrophysics Data System (ADS)

Krueger, Ronald R.; Quantock, Andrew J.; Ito, Mitsutoshi; Assil, Kerry K.; Schanzlin, David J.

1995-05-01

Picosecond intrastromal ablation is currently under investigation as a new minimally invasive way of correcting refractive error. When the laser pulses are placed in an expanding spiral pattern along a lamellar plane, the technique is called intrastromal photorefractive keratectomy (ISPRK). We performed ISPRK on six human eye bank eyes. Thirty picosecond pulses at 1000 Hz and 20 - 25 (mu) J per pulse were separated by 15 microns. A total of 3 layers were placed in the anterior stroma separated by 15 microns. The eyes were then preserved and sectioned for light, scanning and transmission electron microscopy. Light and scanning electron microscopy reveals that picosecond intrastromal ablation using an ISPRK pattern demonstrates multiple, coalescing intrastromal cavities oriented parallel to the corneal surface. These cavities possess a smooth appearing inner wall. Using transmission electron microscopy, we noticed tissue loss surrounding some cavities with collagen fibril termination and thinning of collagen lamella. Other cavities we formed by separation of lamella with little evidence of tissue loss. A pseudomembrane lines the edge of some cavities. Although underlying tissue disruption was occasionally seen along the border of a cavity in no case was there any evidence of thermal damage or tissue necrosis. Ablation and loss of tissue in ISPRK results in nonthermal microscopic corneal thinning around some cavities whereas others demonstrate only lamellar separation. Alternative patterns and energy parameters should be investigated to bring this technology to its full potential in refractive surgery.

Development and Characterization of Acellular Extracellular Matrix Scaffolds from Porcine Menisci for Use in Cartilage Tissue Engineering

PubMed Central

Chen, Ying-Chen; Chen, Ray-Neng; Jhan, Hua-Jing; Liu, Der-Zen; Ho, Hsiu-O; Mao, Yong; Kohn, Joachim

2015-01-01

Given the growing number of arthritis patients and the limitations of current treatments, there is great urgency to explore cartilage substitutes by tissue engineering. In this study, we developed a novel decellularization method for menisci to prepare acellular extracellular matrix (ECM) scaffolds with minimal adverse effects on the ECM. Among all the acid treatments, formic acid treatment removed most of the cellular contents and preserved the highest ECM contents in the decellularized porcine menisci. Compared with fresh porcine menisci, the content of DNA decreased to 4.10%±0.03%, and there was no significant damage to glycosaminoglycan (GAG) or collagen. Histological staining also confirmed the presence of ECM and the absence of cellularity. In addition, a highly hydrophilic scaffold with three-dimensional interconnected porous structure was fabricated from decellularized menisci tissue. Human chondrocytes showed enhanced cell proliferation and synthesis of chondrocyte ECM including type II collagen and GAG when cultured in this acellular scaffold. Moreover, the scaffold effectively supported chondrogenesis of human bone marrow-derived mesenchymal stem cells. Finally, in vivo implantation was conducted in rats to assess the biocompatibility of the scaffolds. No significant inflammatory response was observed. The acellular ECM scaffold provided a native environment for cells with diverse physiological functions to promote cell proliferation and new tissue formation. This study reported a novel way to prepare decellularized meniscus tissue and demonstrated the potential as scaffolds to support cartilage repair. PMID:25919905

Confocal laser endomicroscopy for brain tumor surgery: a milestone journey from microscopy to cellular surgery (Conference Presentation)

NASA Astrophysics Data System (ADS)

Charalampaki, Cleopatra

2017-02-01

The aim in brain tumor surgery is maximal tumor resection with minimal damage of normal neuronal tissue. Today diagnosis of tumor and definition of tumor borders intraoperatively is based on various visualization methods as well as on the histopathologic examination of a limited number of biopsy specimens via frozen sections. Unfortunately, intraoperative histopathology bears several shortcomings, and many biopsies are inconclusive. Therefore, the desirable treatment could be to have the ability to identify intraoperative cellular structures, and differentiate tumor from normal functional brain tissue on a cellular level. To achieve this goal new technological equipment integrated with new surgical concepts is needed.Confocal Laser Endomicroscopy (CLE) is an imaging technique which provides microscopic information of tissue in real-time. We are able to use these technique to perform intraoperative "optical biopsies" in bringing the microscope inside to the patients brain through miniaturized fiber-optic probes, and allow real-time histopathology. In our knowledge we are worldwide the only one neurosurgical group using CLE intraoperative for brain tumor surgery. We can detect and characterize intraoperative tumor cells, providing immediate online diagnosis without the need for frozen sections. It also provides delineation of borders between tumor and normal tissue on a cellular level, making surgical margins more accurate than ever before. The applications of CLE-assisted neurosurgery help to accurate the therapy by extending the resection borders and protecting the functionality of normal brain tissue in critical eloquent areas.

[Physical and chemical emergencies in dermatology].

PubMed

Malisiewicz, B; Meissner, M; Kaufmann, R; Valesky, E

2018-05-01

Physical and chemical emergencies are often caused by household or work accidents. Regardless of the medical field and outside specialized clinics, the physician may be confronted with the situation for first or secondary care. The identification of the causing agent and a rapid assessment of the extent and severity of the tissue damage are essential to initiate early transfer to a specialized burn clinic. Grade 2b tissue damage is usually surgically treated. Smaller and superficial injuries can often be conservatively treated. Even supposedly safe and over-the-counter medicines can also lead to serious tissue damage.

Endovascular revascularization of external carotid artery occlusion causing tongue infarction: case report.

PubMed

Kagami, Hiroshi; Inaba, Makoto; Ichimura, Shinya; Hara, Koichi; Inamasu, Joji

2012-01-01

A 62-year-old man with diabetes and a history of ischemic coronary disease visited the emergency department complaining of acute pain and swelling of the tongue. Physical examination found subtle swelling and pallor of the right side of the tongue, and he was initially diagnosed with glossitis. However, his symptoms were progressive, and the tongue had sustained serious tissue damage before the correct diagnosis was established. Digital subtraction angiography of the cervical vessels revealed occlusion of the right external carotid artery (ECA) and lingual artery without collateral circulation to the right side of the tongue from the contralateral ECA or ipsilateral vertebral artery (VA). Endovascular revascularization was performed to restore blood flow to the tongue using balloon angioplasty of the proximal segment of the right ECA followed by deployment of a self-expanding stent. Tongue pain subsided shortly after the procedure, and configuration of the tongue returned to normal 4 months after intervention. Tongue infarction is rare and usually associated with systemic vasculitides. Tongue infarction due to unilateral occlusion of the ECA is extremely rare because of the rich collateral circulation to the tongue from the ipsilateral VA and contralateral ECA. Atherothrombotic unilateral occlusion of the ECA should be included in the differential diagnosis of tongue infarction. Revascularization of the occluded ECA is worth attempting despite substantial tissue damage because of the viability of the tongue muscles and the minimal risk of complications in experienced hands.

Targeted Interleukin-10 Nanotherapeutics Developed with a Microfluidic Chip Enhance Resolution of Inflammation in Advanced Atherosclerosis.

PubMed

Kamaly, Nazila; Fredman, Gabrielle; Fojas, Jhalique Jane R; Subramanian, Manikandan; Choi, Won Ii; Zepeda, Katherine; Vilos, Cristian; Yu, Mikyung; Gadde, Suresh; Wu, Jun; Milton, Jaclyn; Carvalho Leitao, Renata; Rosa Fernandes, Livia; Hasan, Moaraj; Gao, Huayi; Nguyen, Vance; Harris, Jordan; Tabas, Ira; Farokhzad, Omid C

2016-05-24

Inflammation is an essential protective biological response involving a coordinated cascade of signals between cytokines and immune signaling molecules that facilitate return to tissue homeostasis after acute injury or infection. However, inflammation is not effectively resolved in chronic inflammatory diseases such as atherosclerosis and can lead to tissue damage and exacerbation of the underlying condition. Therapeutics that dampen inflammation and enhance resolution are currently of considerable interest, in particular those that temper inflammation with minimal host collateral damage. Here we present the development and efficacy investigations of controlled-release polymeric nanoparticles incorporating the anti-inflammatory cytokine interleukin 10 (IL-10) for targeted delivery to atherosclerotic plaques. Nanoparticles were nanoengineered via self-assembly of biodegradable polyester polymers by nanoprecipitation using a rapid micromixer chip capable of producing nanoparticles with retained IL-10 bioactivity post-exposure to organic solvent. A systematic combinatorial approach was taken to screen nanoparticles, resulting in an optimal bioactive formulation from in vitro and ex vivo studies. The most potent nanoparticle termed Col-IV IL-10 NP22 significantly tempered acute inflammation in a self-limited peritonitis model and was shown to be more potent than native IL-10. Furthermore, the Col-IV IL-10 nanoparticles prevented vulnerable plaque formation by increasing fibrous cap thickness and decreasing necrotic cores in advanced lesions of high fat-fed LDLr(-/-) mice. These results demonstrate the efficacy and pro-resolving potential of this engineered nanoparticle for controlled delivery of the potent IL-10 cytokine for the treatment of atherosclerosis.

Improved photoacoustic dosimetry for retinal laser surgery

NASA Astrophysics Data System (ADS)

Dufour, Suzie; Brown, Robert B.; Gallant, Pascal; Mermut, Ozzy

2018-02-01

Lasers are employed for numerous medical interventions by exploiting ablative, disruptive or thermal effects. In ocular procedures, lasers have been used for decades to treat diseases such as diabetic retinopathy, macular edema and aged related macular degeneration via photocoagulation of retinal tissues. Although laser photocoagulation is well established in today's practice, efforts to improve clinical outcomes by reducing the collateral damage from thermal diffusion is leading to novel treatments using shorter (μs) laser pulses (e.g. selective retinal therapy) which result in physical rather than thermal damage. However, for these new techniques to be widely utilized, a method is required to ensure safe but sufficient dosage has been applied, since no visible effects can be seen by ophthalmoscopy directly post treatment. Photoacoustic feedback presents an attractive solution, as the signal is dependent directly on absorbed dosage. Here, we present a method that takes advantage of temporal pulse formatting technology to minimize variation in absorbed dose in ophthalmic laser treatment and provide intelligent dosimetry feedback based on photoacoustic (PA) response. This method tailors the pulse to match the frequency response of the sample and/or detection chain. Depending on the system, this may include the absorbing particle size, the laser beam diameter, the laser pulse duration, tissue acoustic properties and the acoustic detector frequency response. A significant improvement (<7x) of photoacoustic signal-to-noise ratio over equivalent traditional pulse formats have been achieved, while spectral analysis of the detected signal provides indications of cavitation events and other sample properties.

A gene therapy induced emphysema model and the protective role of stem cells.

PubMed

Zarogoulidis, Paul; Hohenforst-Schmidt, Wolfgang; Huang, Haidong; Sahpatzidou, Despoina; Freitag, Lutz; Sakkas, Leonidas; Rapti, Aggeliki; Kioumis, Ioannis; Pitsiou, Georgia; Kouzi-Koliakos, Kokkona; Papamichail, Anna; Papaiwannou, Antonis; Tsiouda, Theodora; Tsakiridis, Kosmas; Porpodis, Konstantinos; Lampaki, Sofia; Organtzis, John; Gschwendtner, Andreas; Zarogoulidis, Konstantinos

2014-11-14

Chronic obstructive pulmonary disease presents with two different phenotypes: chronic bronchitis and emphysema with parenchymal destruction. Decreased expression of vascular endothelial growth factor and increased endothelial cell apoptosis are considered major factors for emphysema. Stem cells have the ability of vascular regeneration and function as a repair mechanism for the damaged endothelial cells. Currently, minimally invasive interventional procedures such as placement of valves, bio-foam or coils are performed in order to improve the disturbed mechanical function in emphysema patients. However, these procedures cannot restore functional lung tissue. Additionally stem cell instillation into the parenchyma has been used in clinical studies aiming to improve overall respiratory function and quality of life. In our current experiment we induced emphysema with a DDMC non-viral vector in BALBC mice and simultaneously instilled stem cells testing the hyposthesis that they might have a protective role against the development of emphysema. The mice were divided into four groups: a) control, b) 50.000 cells, c) 75.000 and d) 100.000 cells. Lung pathological findings revealed that all treatment groups had less damage compared to the control group. Additionally, we observed that emphysema lesions were less around vessels in an area of 10 μm. Our findings indicate that stem cell instillation can have a regenerative role if applied upon a tissue scaffold with vessel around. The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_195.

[Case study with a gunshot fracture of lower extremities and damage of popliteal artery (case report)].

PubMed

Orakhelashvili, G A; Kapanadze, L P; Bregadze, G I; Kacharava, B D; Dzagnidze, E B

2011-12-01

Severe vascular gunshot injury (popliteal artery damage) and fractures of both low extremities are causes traumatic shock (stage III) and anemia in a 32 years female patient. Being the victim of crime, the patient for 5 hours was in a life-threatening condition that could develop the multiple organ system failure (MOSF) as a result of tissue ischemia and reperfusion and acute irreversible shock. There was an urgent necessity to perform three immediate operations at the same time. Successful recovery required rapid control of the inciting event (i.e., maintenance of effective hemodynamic stability and the body's ability to protect its vital organs, choice of the type of anesthesia with certain anesthetics) facilitated by resuscitative therapy directed toward minimizing the overall "dose" of shock. Oxybutirate sodium (a GABA analog, the only one narcotic drug and a natural metabolite of body) administered intravenously as a hypnotic agent and an important component of intensive care as well have had clearly anti-shock and antihypoxant effects. Rapid improving of circulation and using of medications with wide range of anti-stress action (such as oxybutirate sodium, dexamethazone and glucose) assisted successful resuscitation and possibility to perform three operations (duration: 6 hours and 45 minutes). An increasing emphasis was being placed on prevention of MOSF, including 1) maintenance of tissue oxygenation; 2) using above-mentioned anti-stress and antihypoxant medicines with mutually supportive effects and 3) infection control.

A quantitative and non-contact technique to characterise microstructural variations of skin tissues during photo-damaging process based on Mueller matrix polarimetry.

PubMed

Dong, Yang; He, Honghui; Sheng, Wei; Wu, Jian; Ma, Hui

2017-10-31

Skin tissue consists of collagen and elastic fibres, which are highly susceptible to damage when exposed to ultraviolet radiation (UVR), leading to skin aging and cancer. However, a lack of non-invasive detection methods makes determining the degree of UVR damage to skin in real time difficult. As one of the fundamental features of light, polarization can be used to develop imaging techniques capable of providing structural information about tissues. In particular, Mueller matrix polarimetry is suitable for detecting changes in collagen and elastic fibres. Here, we demonstrate a novel, quantitative, non-contact and in situ technique based on Mueller matrix polarimetry for monitoring the microstructural changes of skin tissues during UVR-induced photo-damaging. We measured the Mueller matrices of nude mouse skin samples, then analysed the transformed parameters to characterise microstructural changes during the skin photo-damaging and self-repairing processes. Comparisons between samples with and without the application of a sunscreen showed that the Mueller matrix-derived parameters are potential indicators for fibrous microstructure in skin tissues. Histological examination and Monte Carlo simulations confirmed the relationship between the Mueller matrix parameters and changes to fibrous structures. This technique paves the way for non-contact evaluation of skin structure in cosmetics and dermatological health.

Contrasting cellular damage after Blue-IRIS and Femto-LASIK in cat cornea.

PubMed

Wozniak, Kaitlin T; Elkins, Noah; Brooks, Daniel R; Savage, Daniel E; MacRae, Scott; Ellis, Jonathan D; Knox, Wayne H; Huxlin, Krystel R

2017-12-01

Blue-intra-tissue refractive index shaping (Blue-IRIS) is a new approach to laser refractive correction of optical aberrations in the eye, which alters the refractive index of the cornea rather than changing its shape. Before it can be implemented in humans, it is critical to establish whether and to what extent, Blue-IRIS damages the cornea. Here, we contrasted the impact of -1.5 D cylinder refractive corrections inscribed using either Blue-IRIS or femtosecond laser in-situ keratomileusis (femto-LASIK) on corneal cell viability. Blue-IRIS was used to write a -1.5 D cylinder gradient index (GRIN) lens over a 2.5 mm by 2.5 mm area into the mid-stromal region of the cornea in six freshly-enucleated feline eyes. The same correction (-1.5 D cylinder) was inscribed into another four cat eyes using femto-LASIK. Six hours later, all corneas were processed for histology and stained for terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL) and p-γ-H2AX to label damaged cells. In Blue-IRIS-treated corneas, no tissue was removed and TUNEL-stained cells were confined to the laser focal zone in the stroma. In femto-LASIK, photoablation removed 14 μm of anterior stroma, but in addition, TUNEL-positive cells clustered across the femto-flap, the epithelium at the flap edges and the stroma below the ablation zone. Keratocytes positive for p-γ-H2AX were seen adjacent to all Blue-IRIS focal zones, but were completely absent from femto-LASIK-treated corneas. Unlike femto-LASIK, Blue-IRIS attains refractive correction in the cornea without tissue removal and only causes minimal, localized keratocyte death within the laser focal zones. In addition, Blue-IRIS induced DNA modifications associated with phosphorylation of γ-H2AX in keratocytes adjacent to the laser focal zones. We posit that this p-γ-H2AX response is related to alterations in chromatin structure caused by localized changes in osmolarity, a possible mechanism for the induced refractive index changes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Intrastromal corneal reshaping using a high-intensity femtosecond laser: A novel method of vision correction

NASA Astrophysics Data System (ADS)

Han, Taehee

A new technology to perform a minimally invasive cornea reshaping procedure has been developed. This can eliminate the incidence of the flap-related complications of the conventional eye refractive procedures by multiphoton processes using a very high-intensity (I ≥ 1013 W/cm 2), but low energy (Ep ˜ 100-200 microJ) femtosecond laser pulses. Due to much lower energy than that of the nanosecond laser pulses for the thermal photoablation, the multiphoton processes cause almost no collateral damage by heat and shock wave generation. In this method, a series of femtosecond laser pulses is used to create very narrow (< 30 microm) and sufficiently long (≥ 2.5 mm) micro-channels in the cornea. The micro-channels are oriented almost perpendicular to the eye's optical axis. Once the micro-channel reaches a desired length, another series of femtosecond pulses with higher intensity is efficiently delivered through the micro-channel to the endpoint where a certain amount of the stromal tissue is disintegrated by the multiphoton processes. The disintegrated fragments are ejected out of the cornea via the same micro-channel, allowing the corneal surface to collapse, and changing its refractive power. This new corneal reshaping method obviates any process of damaging the corneal surface layer, while retaining the advantages of the conventional refractive procedures such as Laser in situ keratomileusis (LASIK) and Photorefractive keratectomy (PRK). In order to demonstrate the flapless cornea reshaping procedure, we have conducted ex-vivo experiments on fresh porcine eyes. The reshaped corneas were evaluated by using optical coherence tomography (OCT). The test results have shown that this flapless intrastromal procedure can reshape the cornea as intended with almost no surface damage. We have also performed a series of experiments to demonstrate the multiphoton processes in the corneal tissue by very high-intensity femtosecond laser pulses. Through the optical emission spectroscopy, we investigated the spectral lines of calcium atom and ions from the femtosecond laser-induced plasma from the porcine corneal tissue. The experimental results have shown the intensity-dependence of ablation rate, which qualitatively verifies the characteristics of the multiphoton processes.

The comparison of thermal tissue injuries caused by ultrasonic scalpel and electrocautery use in rabbit tongue tissue

PubMed Central

Beriat, Guclu Kaan; Akmansu, Sefik Halit; Ezerarslan, Hande; Dogan, Cem; Han, Unsal; Saglam, Mehmet; Senel, Oytun Okan; Kocaturk, Sinan

2012-01-01

The aim of this study compares to the increase in tissue temperature and the thermal histological effects of ultrasonic scalpel, bipolar and unipolar electrosurgery incisions in the tongue tissue of rabbits. This study evaluates the histopathological changes related to thermal change and the maximum temperature values in the peripheral tissue brought about by the incisions carried out by the three methods in a comparative way. To assess thermal tissue damage induced by the three instruments, maximum tissue temperatures were measured during the surgical procedure and tongue tissue samples were examined histopathologically following the surgery. The mean maximum temperature values of the groups were 93.93±2.76 C° for the unipolar electrocautery group, whereas 85.07±5.95 C° for the bipolar electrocautery group, and 108.23±7.64 C° for the ultrasonic scalpel group. There was a statistically significant relationship between the increase in maximum temperature values and the separation among tissue layers, edema, congestion, necrosis, hemorrhage, destruction in blood vessel walls and fibrin accumulation, and between the existence of fibrin thrombus and tissue damage depth (p<0.05). It was concluded that the bipolar electrocautery use gives way to less temperature increase in the tissues and less thermal tissue damage in comparison to the other methods. PMID:22938541

Systemic Mesenchymal Stromal Cell Transplantation Prevents Functional Bone Loss in a Mouse Model of Age-Related Osteoporosis.

PubMed

Kiernan, Jeffrey; Hu, Sally; Grynpas, Marc D; Davies, John E; Stanford, William L

2016-05-01

Age-related osteoporosis is driven by defects in the tissue-resident mesenchymal stromal cells (MSCs), a heterogeneous population of musculoskeletal progenitors that includes skeletal stem cells. MSC decline leads to reduced bone formation, causing loss of bone volume and the breakdown of bony microarchitecture crucial to trabecular strength. Furthermore, the low-turnover state precipitated by MSC loss leads to low-quality bone that is unable to perform remodeling-mediated maintenance--replacing old damaged bone with new healthy tissue. Using minimally expanded exogenous MSCs injected systemically into a mouse model of human age-related osteoporosis, we show long-term engraftment and markedly increased bone formation. This led to improved bone quality and turnover and, importantly, sustained microarchitectural competence. These data establish proof of concept that MSC transplantation may be used to prevent or treat human age-related osteoporosis. This study shows that a single dose of minimally expanded mesenchymal stromal cells (MSCs) injected systemically into a mouse model of human age-related osteoporosis display long-term engraftment and prevent the decline in bone formation, bone quality, and microarchitectural competence. This work adds to a growing body of evidence suggesting that the decline of MSCs associated with age-related osteoporosis is a major transformative event in the progression of the disease. Furthermore, it establishes proof of concept that MSC transplantation may be a viable therapeutic strategy to treat or prevent human age-related osteoporosis. ©AlphaMed Press.

Systemic Mesenchymal Stromal Cell Transplantation Prevents Functional Bone Loss in a Mouse Model of Age-Related Osteoporosis

PubMed Central

Kiernan, Jeffrey; Hu, Sally; Grynpas, Marc D.

2016-01-01

Age-related osteoporosis is driven by defects in the tissue-resident mesenchymal stromal cells (MSCs), a heterogeneous population of musculoskeletal progenitors that includes skeletal stem cells. MSC decline leads to reduced bone formation, causing loss of bone volume and the breakdown of bony microarchitecture crucial to trabecular strength. Furthermore, the low-turnover state precipitated by MSC loss leads to low-quality bone that is unable to perform remodeling-mediated maintenance—replacing old damaged bone with new healthy tissue. Using minimally expanded exogenous MSCs injected systemically into a mouse model of human age-related osteoporosis, we show long-term engraftment and markedly increased bone formation. This led to improved bone quality and turnover and, importantly, sustained microarchitectural competence. These data establish proof of concept that MSC transplantation may be used to prevent or treat human age-related osteoporosis. Significance This study shows that a single dose of minimally expanded mesenchymal stromal cells (MSCs) injected systemically into a mouse model of human age-related osteoporosis display long-term engraftment and prevent the decline in bone formation, bone quality, and microarchitectural competence. This work adds to a growing body of evidence suggesting that the decline of MSCs associated with age-related osteoporosis is a major transformative event in the progression of the disease. Furthermore, it establishes proof of concept that MSC transplantation may be a viable therapeutic strategy to treat or prevent human age-related osteoporosis. PMID:26987353

Histological evaluation and optimization of surgical vessel sealing systems

NASA Astrophysics Data System (ADS)

Lathrop, Robert; Ryan, Thomas; Gaspredes, Jonathan; Woloszko, Jean; Coad, James E.

2017-02-01

Surgical vessel sealing systems are widely used to achieve hemostasis and dissection in open surgery and minimally invasive, laparoscopic surgery. This enabling technology was developed about 17 years ago and continues to evolve with new devices and systems achieving improved outcomes. Histopathological assessment of thermally sealed tissues is a valuable tool for refining and comparing performance among surgical vessel sealing systems. Early work in this field typically assessed seal time, burst rate, and failure rate (in-situ). Later work compared histological staining methods with birefringence to assess the extent of thermal damage to tissues adjacent to the device. Understanding the microscopic architecture of a sealed vessel is crucial to optimizing the performance of power delivery algorithms and device design parameters. Manufacturers rely on these techniques to develop new products. A system for histopathological evaluation of vessels and sealing performance was established, to enable the direct assessment of a treatment's tissue effects. The parameters included the commonly used seal time, pressure burst rate and failure rate, as well as extensions of the assessment to include its likelihood to form steam vacuoles, adjacent thermal effect near the device, and extent of thermally affected tissue extruded back into the vessel lumen. This comprehensive assessment method provides an improved means of assessing the quality of a sealed vessel and understanding the exact mechanisms which create an optimally sealed vessel.

Role of contact inhibition of locomotion and junctional mechanics in epithelial collective responses to injury

NASA Astrophysics Data System (ADS)

Coburn, Luke; Lopez, Hender; Schouwenaar, Irin-Maya; Yap, Alpha S.; Lobaskin, Vladimir; Gomez, Guillermo A.

2018-03-01

Epithelial tissues form physically integrated barriers against the external environment protecting organs from infection and invasion. Within each tissue, epithelial cells respond to different challenges that can potentially compromise tissue integrity. In particular, cells collectively respond to injuries by reorganizing their cell-cell junctions and migrating directionally towards the sites of damage. Notwithstanding, the mechanisms that drive collective responses in epithelial aggregates remain poorly understood. In this work, we develop a minimal mechanistic model that is able to capture the essential features of epithelial collective responses to injuries. We show that a model that integrates the mechanics of cells at the cell-cell and cell-substrate interfaces as well as contact inhibition of locomotion (CIL) correctly predicts two key properties of epithelial response to injury as: (1) local relaxation of the tissue and (2) collective reorganization involving the extension of cryptic lamellipodia that extend, on average, up to 3 cell diameters from the site of injury and morphometric changes in the basal regions. Our model also suggests that active responses (like the actomyosin purse string and softening of cell-cell junctions) are needed to drive morphometric changes in the apical region. Therefore, our results highlight the importance of the crosstalk between junctional biomechanics, cell substrate adhesion, and CIL, as well as active responses, in guiding the collective rearrangements that are required to preserve the epithelial barrier in response to injury.

Milk phospholipid's protective effects against UV damage in skin equivalent models

NASA Astrophysics Data System (ADS)

Dargitz, Carl; Russell, Ashley; Bingham, Michael; Achay, Zyra; Jimenez-Flores, Rafael; Laiho, Lily H.

2012-03-01

Exposure of skin tissue to UV radiation has been shown to cause DNA photodamage. If this damaged DNA is allowed to replicate, carcinogenesis may occur. DNA damage is prevented from being passed on to daughter cells by upregulation of the protein p21. p21 halts the cells cycle allowing the cell to undergo apoptosis, or repair its DNA before replication. Previous work suggested that milk phospholipids may possess protective properties against UV damage. In this study, we observed cell morphology, cell apoptosis, and p21 expression in tissue engineered epidermis through the use of Hematoxylin and Eosin staining, confocal microscopy, and western blot respectively. Tissues were divided into four treatment groups including: a control group with no UV and no milk phospholipid treatment, a group exposed to UV alone, a group incubated with milk phospholipids alone, and a group treated with milk phospholipids and UV. All groups were incubated for twenty-four hours after treatment. Tissues were then fixed, processed, and embedded in paraffin. Performing western blots resulted in visible p21 bands for the UV group only, implying that in every other group, p21 expression was lesser. Numbers of apoptotic cells were determined by observing the tissues treated with Hoechst dye under a confocal microscope, and counting the number of apoptotic and total cells to obtain a percentage of apoptotic cells. We found a decrease in apoptotic cells in tissues treated with milk phospholipids and UV compared to tissues exposed to UV alone. Collectively, these results suggest that milk phospholipids protect cell DNA from damage incurred from UV light.

Intraocular tissue ablation using an optical fibre to deliver the 5th harmonic of a Nd:YAG

NASA Astrophysics Data System (ADS)

Miller, Joseph; Yu, Xiaobo; Yu, Paula K.; Cringle, Stephen J.; Yu, Dao-Yi

2009-02-01

We report the evaluation of a system which delivers the 5th harmonic of an Nd:YAG (213nm) via optical fibre to ocular tissue sites. The 213nm beam is concentrated, using a hollow glass taper, prior to launch into 200 μm or 600 μm core diameter silica/silica optical fibre. The fibre tip was tapered to enhance the fluence delivered. An operating window of fluence values that could be delivered via 330 - 1100mm lengths of optical fibre was determined. The lower value of 0.2J/cm2 determined by the ablation threshold of the tissue and the upper value of 1.3J/cm2 by the launch, transmission and tip characteristics of the optical fibre. The fluence output decreased as a function of both transmitted pulse energy and number of pulses transmitted. Fresh retinal tissue was cleanly ablated with minimal damage to the surrounding tissue. Lesions were generated using 1, 3 and 10 pulses with fluences from 0.2 to 1.0J/cm2. The lesion depth demonstrated clear dose dependence. Lesions generated in ex vivo preparations of human trabecular meshwork in a fluid environment also demonstrated dose dependence, 50 pulses being sufficient to create a hole within the trabecular meshwork extending to Schlemm's canal. The dose dependence of the ablation depth combined with the ability of this technique to create a conduit through to Schlemm's canal demonstrates the potential of this technique for ophthalmological applications requiring precise and controlled intraocular tissue removal and has potential applications in the treatment and management of glaucoma.

Comparison of porcine thorax to gelatine blocks for wound ballistics studies.

PubMed

Mabbott, A; Carr, D J; Champion, S; Malbon, C

2016-09-01

Tissue simulants are typically used in ballistic testing as substitutes for biological tissues. Many simulants have been used, with gelatine amongst the most common. While two concentrations of gelatine (10 and 20 %) have been used extensively, no agreed standard exists for the preparation of either. Comparison of ballistic damage produced in both concentrations is lacking. The damage produced in gelatine is also questioned, with regards to what it would mean for specific areas of living tissue. The aim of the work discussed in this paper was to consider how damage caused by selected pistol and rifle ammunition varied in different simulants. Damage to gelatine blocks 10 and 20 % in concentration were tested with 9 mm Luger (9 × 19 full metal jacket; FMJ) rounds, while damage produced by .223 Remington (5.56 × 45 Federal Premium® Tactical® Bonded®) rounds to porcine thorax sections (skin, underlying tissue, ribs, lungs, ribs, underlying tissue, skin; backed by a block of 10 % gelatine) were compared to 10 and 20 % gelatine blocks. Results from the .223 Remington rifle round, which is one that typically expands on impact, revealed depths of penetration in the thorax arrangement were significantly different to 20 % gelatine, but not 10 % gelatine. The level of damage produced in the simulated thoraxes was smaller in scale to that witnessed in both gelatine concentrations, though greater debris was produced in the thoraxes.

Thresholds for thermal damage to normal tissues: an update.

PubMed

Yarmolenko, Pavel S; Moon, Eui Jung; Landon, Chelsea; Manzoor, Ashley; Hochman, Daryl W; Viglianti, Benjamin L; Dewhirst, Mark W

2011-01-01

The purpose of this review is to summarise a literature survey on thermal thresholds for tissue damage. This review covers published literature for the consecutive years from 2002-2009. The first review on this subject was published in 2003. It included an extensive discussion of how to use thermal dosimetric principles to normalise all time-temperature data histories to a common format. This review utilises those same principles to address sensitivity of a variety of tissues, but with particular emphasis on brain and testis. The review includes new data on tissues that were not included in the original review. Several important observations have come from this review. First, a large proportion of the papers examined for this review were discarded because time-temperature history at the site of thermal damage assessment was not recorded. It is strongly recommended that future research on this subject include such data. Second, very little data is available examining chronic consequences of thermal exposure. On a related point, the time of assessment of damage after exposure is critically important for assessing whether damage is transient or permanent. Additionally, virtually no data are available for repeated thermal exposures which may occur in certain recreational or occupational activities. For purposes of regulatory guidelines, both acute and lasting effects of thermal damage should be considered.

Gene Suppression of Mouse Testis In Vivo Using Small Interfering RNA Derived from Plasmid Vectors

PubMed Central

Takizawa, Takami; Ishikawa, Tomoko; Kosuge, Takuji; Mizuguchi, Yoshiaki; Sato, Yoko; Koji, Takehiko; Araki, Yoshihiko; Takizawa, Toshihiro

2012-01-01

We evaluated whether inhibiting gene expression by small interfering RNA (siRNA) can be used for an in vivo model using a germ cell-specific gene (Tex101) as a model target in mouse testis. We generated plasmid-based expression vectors of siRNA targeting the Tex101 gene and transfected them into postnatal day 10 mouse testes by in vivo electroporation. After optimizing the electroporation conditions using a vector transfected into the mouse testis, a combination of high- and low-voltage pulses showed excellent transfection efficiency for the vectors with minimal tissue damage, but gene suppression was transient. Gene suppression by in vivo electroporation may be helpful as an alternative approach when designing experiments to unravel the basic role of testicular molecules. PMID:22489107

Skin Damage Assessment by Ultrasonic Waves

NASA Technical Reports Server (NTRS)

1991-01-01

Effective treatment of serious burns is dependent on early recognition of the extent of dead tissue and its removal to minimize the risk of infection and hasten healing. To meet the need for precise determination of burn depth, two physicists from Langley's Nondestructive Measurement Science Branch in cooperation with the Medical College of Virginia, Richmond, the University of Aberdeen, Scotland, and the NASA Technology Application Team, Research Triangle Institute, developed a prototype system that used ultrasound technology (originally developed as a means of detecting microscopic flaws in materials) for immediate assessment of burn depth. The system was commercialized by Westminster Supra Scanner, Inc., Orangeburg, NY, is produced under a NASA license, and was granted Food and Drug Administration approval in December 1990. It can be applied to the diagnosis of lymphatic disorders.

A perspective of gene therapy in the glaucomas.

PubMed

Kaufman, P L; Jia, W W; Tan, J; Chen, Z; Gabelt, B T; Booth, V; Tufaro, F; Cynader, M

1999-06-01

Gene therapy in the anterior and posterior segment tissues may have the potential to favorably influence aqueous hydrodynamics and retinal ganglion cell biology, thereby preventing, delaying, or minimizing glaucomatous damage to the optic nerve. We demonstrated the feasibility of using a herpes viral vector (ribonucleotide reductase defective HSV-1, hrR3) to deliver the lacZ reporter gene to living cat and rat eyes. Cats received injections into the anterior chamber and rats into the vitreous cavity. In cats, lacZ expression was detectable at 1 to 2 days in the anterior outer portion of the ciliary muscle and the lining of the intertrabecular spaces of the corneoscleral and uveal meshwork. Rat eyes showed lacZ expression in the retinal pigment epithelium and photoreceptor outer segments 2 days after injection.

Complement component C5a mediates hemorrhage-induced intestinal damage

PubMed Central

Fleming, Sherry D.; Phillips, Lauren M.; Lambris, John D.; Tsokos, George C.

2008-01-01

Background Complement has been implicated in the pathogenesis of intestinal damage and inflammation in multiple animal models. Although the exact mechanism is unknown, inhibition of complement prevents hemodynamic alterations in hemorrhage. Materials/Methods C57Bl/6, complement 5 deficient (C5−/−) and sufficient (C5+/+) mice were subjected to 25% blood loss. In some cases, C57Bl/6 mice were treated with C5a receptor antagonist (C5aRa) post-hemorrhage. Intestinal injury, leukotriene B4, and myeloperoxidase production were assessed for each treatment group of mice. Results Mice subjected to significant blood loss without major trauma develop intestinal inflammation and tissue damage within two hours. We report here that complement 5 (C5) deficient mice are protected from intestinal tissue damage when subjected to hemorrhage (Injury score = 0.36 compared to wildtype hemorrhaged animal injury score = 2.89; p<0.05). We present evidence that C5a represents the effector molecule because C57Bl/6 mice treated with a C5a receptor antagonist displayed limited intestinal injury (Injury score = 0.88), leukotriene B4 (13.16 pg/mg tissue) and myeloperoxidase (115.6 pg/mg tissue) production compared to hemorrhaged C57Bl/6 mice (p<0.05). Conclusion Complement activation is important in the development of hemorrhage-induced tissue injury and C5a generation is critical for tissue inflammation and damage. Thus, therapeutics targeting C5a may be useful therapeutics for hemorrhage-associated injury. PMID:18639891

A study on thermal damage during hyperthermia treatment based on DPL model for multilayer tissues using finite element Legendre wavelet Galerkin approach.

PubMed

Kumar, Dinesh; Rai, K N

2016-12-01

Hyperthermia is a process that uses heat from the spatial heat source to kill cancerous cells without damaging the surrounding healthy tissues. Efficacy of hyperthermia technique is related to achieve temperature at the infected cells during the treatment process. A mathematical model on heat transfer in multilayer tissues in finite domain is proposed to predict the control temperature profile at hyperthermia position. The treatment technique uses dual-phase-lag model of heat transfer in multilayer tissues with modified Gaussian distribution heat source subjected to the most generalized boundary condition and interface at the adjacent layers. The complete dual-phase-lag model of bioheat transfer is solved using finite element Legendre wavelet Galerkin approach. The present solution has been verified with exact solution in a specific case and provides a good accuracy. The effect of the variability of different parameters such as lagging times, external heat source, metabolic heat source and the most generalized boundary condition on temperature profile in multilayer tissues is analyzed and also discussed the effective approach of hyperthermia treatment. Furthermore, we studied the modified thermal damage model with regeneration of healthy tissues as well. For viewpoint of thermal damage, the least thermal damage has been observed in boundary condition of second kind. The article concludes with a discussion of better opportunities for future clinical application of hyperthermia treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modeling of skin cooling, blood flow, and optical properties in wounds created by electrical shock

NASA Astrophysics Data System (ADS)

Nguyen, Thu T. A.; Shupp, Jeffrey W.; Moffatt, Lauren T.; Jordan, Marion H.; Jeng, James C.; Ramella-Roman, Jessica C.

2012-02-01

High voltage electrical injuries may lead to irreversible tissue damage or even death. Research on tissue injury following high voltage shock is needed and may yield stage-appropriate therapy to reduce amputation rate. One of the mechanisms by which electricity damages tissue is through Joule heating, with subsequent protein denaturation. Previous studies have shown that blood flow had a significant effect on the cooling rate of heated subcutaneous tissue. To assess the thermal damage in tissue, this study focused on monitoring changes of temperature and optical properties of skin next to high voltage wounds. The burns were created between left fore limb and right hind limb extremities of adult male Sprague-Dawley rats by a 1000VDC delivery shock system. A thermal camera was utilized to record temperature variation during the exposure. The experimental results were then validated using a thermal-electric finite element model (FEM).

Suppression of Neutrophil-Mediated Tissue Damage—A Novel Skill of Mesenchymal Stem Cells

PubMed Central

Jiang, Dongsheng; Muschhammer, Jana; Qi, Yu; Kügler, Andrea; De Vries, Juliane C.; Saffarzadeh, Mona; Sindrilaru, Anca; Beken, Seppe Vander; Wlaschek, Meinhard; Kluth, Mark A.; Ganss, Christoph; Frank, Natasha Y.; Frank, Markus H.; Preissner, Klaus T.; Scharffetter-Kochanek, Karin

2017-01-01

Mesenchymal stem cells (MSCs) are crucial for tissue homeostasis and regeneration. Though of prime interest, their potentially protective role on neutrophil-induced tissue damage, associated with high morbidity and mortality, has not been explored in sufficient detail. Here we report the therapeutic skill of MSCs to suppress unrestrained neutrophil activation and to attenuate severe tissue damage in a murine immune-complex mediated vasculitis model of unbalanced neutrophil activation. MSC-mediated neutrophil suppression was due to intercellular adhesion molecule 1-dependent engulfment of neutrophils by MSCs, decreasing overall neutrophil numbers. Similar to MSCs in their endogenous niche of murine and human vasculitis, therapeutically injected MSCs via upregulation of the extracellular superoxide dismutase (SOD3), reduced super-oxide anion concentrations and consequently prevented neutrophil death, neutrophil extracellular trap formation and spillage of matrix degrading neutrophil elastase, gelatinase and myeloperoxidase. SOD3-silenced MSCs did not exert tissue protective effects. Thus, MSCs hold substantial therapeutic promise to counteract tissue damage in conditions with unrestrained neutrophil activation. PMID:27299700

Regenerative Repair of Damaged Meniscus with Autologous Adipose Tissue-Derived Stem Cells

PubMed Central

Pak, Jaewoo; Lee, Jung Hun; Lee, Sang Hee

2014-01-01

Mesenchymal stem cells (MSCs) are defined as pluripotent cells found in numerous human tissues, including bone marrow and adipose tissue. Such MSCs, isolated from bone marrow and adipose tissue, have been shown to differentiate into bone and cartilage, along with other types of tissues. Therefore, MSCs represent a promising new therapy in regenerative medicine. The initial treatment of meniscus tear of the knee is managed conservatively with nonsteroidal anti-inflammatory drugs and physical therapy. When such conservative treatment fails, an arthroscopic resection of the meniscus is necessary. However, the major drawback of the meniscectomy is an early onset of osteoarthritis. Therefore, an effective and noninvasive treatment for patients with continuous knee pain due to damaged meniscus has been sought. Here, we present a review, highlighting the possible regenerative mechanisms of damaged meniscus with MSCs (especially adipose tissue-derived stem cells (ASCs)), along with a case of successful repair of torn meniscus with significant reduction of knee pain by percutaneous injection of autologous ASCs into an adult human knee. PMID:24592390

Deep tissue penetration of nanoparticles using pulsed-high intensity focused ultrasound

NASA Astrophysics Data System (ADS)

You, Dong Gil; Yoon, Hong Yeol; Jeon, Sangmin; Um, Wooram; Son, Sejin; Park, Jae Hyung; Kwon, Ick Chan; Kim, Kwangmeyung

2017-11-01

Recently, ultrasound (US)-based drug delivery strategies have received attention to improve enhanced permeation and retention (EPR) effect-based passive targeting efficiency of nanoparticles in vitro and in vivo conditions. Among the US treatment techniques, pulsed-high intensity focused ultrasound (pHIFU) have specialized for improving tissue penetration of various macromolecules and nanoparticles without irreversible tissue damages. In this study, we have demonstrated that pHIFU could be utilized to improve tissue penetration of fluorescent dye-labeled glycol chitosan nanoparticles (FCNPs) in femoral tissue of mice. pHIFU could improve blood flow of the targeted-blood vessel in femoral tissue. In addition, tissue penetration of FCNPs was specifically increased 5.7-, 8- and 9.3-folds than that of non-treated (0 W pHIFU) femoral tissue, when the femoral tissue was treated with 10, 20 and 50 W of pHIFU, respectively. However, tissue penetration of FCNPs was significantly reduced after 3 h post-pHIFU treatment (50 W). Because overdose (50 W) of pHIFU led to irreversible tissue damages, including the edema and chapped red blood cells. These overall results support that pHIFU treatment can enhance the extravasation and tissue penetration of FCNPs as well as induce irreversible tissue damages. We expect that our results can provide advantages to optimize pHIFU-mediated delivery strategy of nanoparticles for further clinical applications.

Reduction of thermal damage in photodynamic therapy by laser irradiation techniques.

PubMed

Lim, Hyun Soo

2012-12-01

General application of continuous-wave (CW) laser irradiation modes in photodynamic therapy can cause thermal damage to normal tissues in addition to tumors. A new photodynamic laser therapy system using a pulse irradiation mode was optimized to reduce nonspecific thermal damage. In in vitro tissue specimens, tissue energy deposition rates were measured in three irradiation modes, CW, pulse, and burst-pulse. In addition, methods were tested for reducing variations in laser output and specific wavelength shifts using a thermoelectric cooler and thermistor. The average temperature elevation per 10 J/cm2 was 0.27°C, 0.09°C, and 0.08°C using the three methods, respectively, in pig muscle tissue. Variations in laser output were controlled within ± 0.2%, and specific wavelength shift was limited to ± 3 nm. Thus, optimization of a photodynamic laser system was achieved using a new pulse irradiation mode and controlled laser output to reduce potential thermal damage during conventional CW-based photodynamic therapy.

The multiple strategies of an insect herbivore to overcome plant cyanogenic glucoside defence.

PubMed

Pentzold, Stefan; Zagrobelny, Mika; Roelsgaard, Pernille Sølvhøj; Møller, Birger Lindberg; Bak, Søren

2014-01-01

Cyanogenic glucosides (CNglcs) are widespread plant defence compounds that release toxic hydrogen cyanide by plant β-glucosidase activity after tissue damage. Specialised insect herbivores have evolved counter strategies and some sequester CNglcs, but the underlying mechanisms to keep CNglcs intact during feeding and digestion are unknown. We show that CNglc-sequestering Zygaena filipendulae larvae combine behavioural, morphological, physiological and biochemical strategies at different time points during feeding and digestion to avoid toxic hydrolysis of the CNglcs present in their Lotus food plant, i.e. cyanogenesis. We found that a high feeding rate limits the time for plant β-glucosidases to hydrolyse CNglcs. Larvae performed leaf-snipping, a minimal disruptive feeding mode that prevents mixing of plant β-glucosidases and CNglcs. Saliva extracts did not inhibit plant cyanogenesis. However, a highly alkaline midgut lumen inhibited the activity of ingested plant β-glucosidases significantly. Moreover, insect β-glucosidases from the saliva and gut tissue did not hydrolyse the CNglcs present in Lotus. The strategies disclosed may also be used by other insect species to overcome CNglc-based plant defence and to sequester these compounds intact.

Improved two-photon imaging of living neurons in brain tissue through temporal gating

PubMed Central

Gautam, Vini; Drury, Jack; Choy, Julian M. C.; Stricker, Christian; Bachor, Hans-A.; Daria, Vincent R.

2015-01-01

We optimize two-photon imaging of living neurons in brain tissue by temporally gating an incident laser to reduce the photon flux while optimizing the maximum fluorescence signal from the acquired images. Temporal gating produces a bunch of ~10 femtosecond pulses and the fluorescence signal is improved by increasing the bunch-pulse energy. Gating is achieved using an acousto-optic modulator with a variable gating frequency determined as integral multiples of the imaging sampling frequency. We hypothesize that reducing the photon flux minimizes the photo-damage to the cells. Our results, however, show that despite producing a high fluorescence signal, cell viability is compromised when the gating and sampling frequencies are equal (or effectively one bunch-pulse per pixel). We found an optimum gating frequency range that maintains the viability of the cells while preserving a pre-set fluorescence signal of the acquired two-photon images. The neurons are imaged while under whole-cell patch, and the cell viability is monitored as a change in the membrane’s input resistance. PMID:26504651

Intraoperative radiotherapy. Literature updating with an overview of results presented at the 6th International Symposium of Intraoperative Radiation Therapy.

PubMed

Calvo, F A; Santos, M; Azinovic, I

1998-01-01

Intraoperative radiotherapy is a technique that can be integrated into multidisciplinary treatment strategies in oncology. A radiation boost delivered with high energy electron beams can intensify locoregional antitumor therapy in patients undergoing cancer surgery. Intraoperative radiotherapy can increase the therapeutic index of the conventional combination of surgery and radiotherapy by improving the precision of radiation dose location, while decreasing the normal tissue damage in mobile structures and enhancing the biological effect of radiation when combined with surgical debulking. Intraoperative radiotherapy has been extensively investigated in clinical oncology in the last 15 years. Commercially available linear accelerators require minimal changes to be suitable for intraoperative radiotherapy. Its successful implementation in clinical protocols depends on the support given by the single institutions and on a clinical research-oriented mentality. Tumors where intraoperative radiotherapy as a treatment component has shown promising rates of local control include locally advanced rectal, gastric and gynecologic cancer, bone and soft tissue sarcoma. Intraoperative radiotherapy can be applied to brain tumors, head and neck cancer, NSCLC and pancreatic carcinoma.

Effect of laser beam on temperature distribution on artificial cylindrical shaped hard tissue bones

NASA Astrophysics Data System (ADS)

Al-Akhras, M.-Ali H.; Qaseer, Mohammad-Khair; Albiss, B. A.; Gezawa, Umar S.

2018-02-01

Samples from fresh lamb chest bones were made in cylindrical shapes to study the time variation of temperature T as functions of the cylindrical radius and depth when its front surface exposed to a laser beam of 110Mw power and 642nm wavelength. The laser beam was directed at the center of the front surface of the horizontal cylinder. The measurements were done in vacuum and at atmospheric pressure. Our data reveal the linear variation of T with time, followed by a gradual increase before it reaches a plateau value at higher time. This sort of behavior independent of the radius or the depth where the temperature was measured. Moreover, the maximum variation occurs on the front surface where the laser beam was hitting and diminishes gradually with depth deep inside the cylinder. Data at atmospheric pressure showed less changes in temperature. The temperature distribution in bone due to laser irradiation is very important for a rational use of laser therapy as well as in the surgery to minimizes the thermal tissue damage.

The MiRNA Journey from Theory to Practice as a CNS Biomarker.

PubMed

Stoicea, Nicoleta; Du, Amy; Lakis, D Christie; Tipton, Courtney; Arias-Morales, Carlos E; Bergese, Sergio D

2016-01-01

MicroRNAs (miRNAs), small nucleotide sequences that control gene transcription, have the potential to serve an expanded function as indicators in the diagnosis and progression of neurological disorders. Studies involving debilitating neurological diseases such as, Alzheimer's disease, multiple sclerosis, traumatic brain injuries, Parkinson's disease and CNS tumors, already provide validation for their clinical diagnostic use. These small nucleotide sequences have several features, making them favorable candidates as biomarkers, including function in multiple tissues, stability in bodily fluids, a role in pathogenesis, and the ability to be detected early in the disease course. Cerebrospinal fluid, with its cell-free environment, collection process that minimizes tissue damage, and direct contact with the brain and spinal cord, is a promising source of miRNA in the diagnosis of many neurological disorders. Despite the advantages of miRNA analysis, current analytic technology is not yet affordable as a clinically viable diagnostic tool and requires standardization. The goal of this review is to explore the prospective use of CSF miRNA as a reliable and affordable biomarker for different neurological disorders.

The MiRNA Journey from Theory to Practice as a CNS Biomarker

PubMed Central

Stoicea, Nicoleta; Du, Amy; Lakis, D. Christie; Tipton, Courtney; Arias-Morales, Carlos E.; Bergese, Sergio D.

2016-01-01

MicroRNAs (miRNAs), small nucleotide sequences that control gene transcription, have the potential to serve an expanded function as indicators in the diagnosis and progression of neurological disorders. Studies involving debilitating neurological diseases such as, Alzheimer's disease, multiple sclerosis, traumatic brain injuries, Parkinson's disease and CNS tumors, already provide validation for their clinical diagnostic use. These small nucleotide sequences have several features, making them favorable candidates as biomarkers, including function in multiple tissues, stability in bodily fluids, a role in pathogenesis, and the ability to be detected early in the disease course. Cerebrospinal fluid, with its cell-free environment, collection process that minimizes tissue damage, and direct contact with the brain and spinal cord, is a promising source of miRNA in the diagnosis of many neurological disorders. Despite the advantages of miRNA analysis, current analytic technology is not yet affordable as a clinically viable diagnostic tool and requires standardization. The goal of this review is to explore the prospective use of CSF miRNA as a reliable and affordable biomarker for different neurological disorders. PMID:26904099

The sinusoidal probe: a new approach to improve electrode longevity

PubMed Central

Sohal, Harbaljit S.; Jackson, Andrew; Jackson, Richard; Clowry, Gavin J.; Vassilevski, Konstantin; O’Neill, Anthony; Baker, Stuart N.

2014-01-01

Micromotion between the brain and implanted electrodes is a major contributor to the failure of invasive brain–machine interfaces. Movements of the electrode tip cause recording instabilities while spike amplitudes decline over the weeks/months post-implantation due to glial cell activation caused by sustained mechanical trauma. We have designed a sinusoidal probe in order to reduce movement of the recording tip relative to the surrounding neural tissue. The probe was microfabricated from flexible materials and incorporated a sinusoidal shaft to minimize tethering forces and a 3D spheroid tip to anchor the recording site within the brain. Compared to standard microwire electrodes, the signal-to-noise ratio and local field potential power of sinusoidal probe recordings from rabbits was more stable across recording periods up to 678 days. Histological quantification of microglia and astrocytes showed reduced neuronal tissue damage especially for the tip region between 6 and 24 months post-implantation. We suggest that the micromotion-reducing measures incorporated into our design, at least partially, decreased the magnitude of gliosis, resulting in enhanced longevity of recording. PMID:24808859

A laser syringe aimed at delivering drug into the outer layer of human skin

NASA Astrophysics Data System (ADS)

Yoh, Jack J.; Jang, Hun-jae; Park, Mi-ae; Han, Tae-hee; Hah, Jung-moo

2012-07-01

A desire to eliminate hypodermic needle in transdermal drug delivery may now be realized. Imaging of the skin after injection of fluorescent probe and biotin via the bio-ballistic technique revealed the epidermal and dermal layers which were stained well below 60 μm underneath the abdominal skin of the guinea-pig. An extensive network of cells are shown in the deeper layer of the stained dermis as the distributed fluorescein isothiocyanate (FITC) dose is administered by repeated injection via the laser-based microjet. Here, we show our method of laser-based microjet drug delivery is capable of breaching guinea-pig's skin tissue and then delivering controlled dose of drug to the targeted region between 10 to 400 μm underneath the outermost layer of the skin. While minimizing pain and tissue damage by reducing the injection volume to ˜100 nl per pulse and the microjet diameter of half the conventional syringe needle in 100 μm, the optimally controlled delivery of liquid drug by the irradiated laser pulse is shown possible.

Risk assessment of the application of a plasma jet in dermatology

NASA Astrophysics Data System (ADS)

Lademann, Juergen; Richter, Heike; Alborova, Alena; Humme, Daniel; Patzelt, Alexa; Kramer, Axel; Weltmann, Klaus-Dieter; Hartmann, Bernd; Ottomann, Christian; Fluhr, Joachim W.; Hinz, Peter; Hübner, Georg; Lademann, Olaf

2009-09-01

Regardless of the fact that several highly efficient antiseptics are commercially available, the antiseptic treatment of chronic wounds remains a problem. In the past, electrical plasma discharges have been frequently used in biometrical science for disinfection and sterilization of material surfaces. Plasma systems usually have a temperature of several hundred degrees. Recently, it was reported that ``cold'' plasma can be applied onto living tissue. In in vitro studies on cell culture, it could be demonstrated that this new plasma possesses excellent antiseptic properties. We perform a risk assessment concerning the in vivo application of a ``cold'' plasma jet on patients and volunteers. Two potential risk factors, UV radiation and temperature, are evaluated. We show that the UV radiation of the plasma in the used system is an order of magnitude lower than the minimal erythema dose, necessary to produce sunburn on the skin in vivo. Additionally, thermal damage of the tissue by the plasma can be excluded. The results of the risk assessment stimulate the in vivo application of the investigated plasma jet in the treatment of chronic wounds.

Role of chemical and mechanical stimuli in mediating bone fracture healing.

PubMed

Zhang, Lihai; Richardson, Martin; Mendis, Priyan

2012-08-01

Bone is a remarkable living tissue that provides a framework for animal body support and motion. However, under excessive loads and deformations, bone is prone is to damage through fracture. Furthermore, once the bone is weakened by osteoporosis, bone fracture can occur even after only minimal trauma. Various techniques have been developed to treat bone fractures. Successful treatment outcomes depend on a fundamental understanding of the biochemical and biomechanical environments of the fracture site. Various cell types (e.g. mesenchymal stem cells, chondrocytes, osteoblasts and osteoclasts) within the fracture site tightly control the healing process by responding to the chemical and mechanical microenvironment. However, these mechanochemical regulatory mechanisms remain poorly understood at the system level owing to the large range of variables, such as age, sex and disease-associated material properties of the tissue. Computational modelling can play an important role in unravelling this complexity by combining mechanochemical interactions, revealing the dominant controlling processes and optimizing system behaviour, thereby enabling the development and evaluation of treatment strategies for individual patients. © 2011 The Authors. Clinical and Experimental Pharmacology and Physiology © 2011 Blackwell Publishing Asia Pty Ltd.

Nanobiotechnology promotes noninvasive high-intensity focused ultrasound cancer surgery.

PubMed

Chen, Yu; Chen, Hangrong; Shi, Jianlin

2015-01-07

The successful cancer eradication in a noninvasive manner is the ultimate objective in the fight against cancer. As a "bloodless scalpel," high-intensity focused ultrasound (HIFU) is regarded as one of the most promising and representative noninvasive therapeutic modalities for cancer surgery. However, large-scale clinical applications of HIFU are still in their infancy because of critical efficiency and safety issues which remain to be solved. Fortunately, recently developed nanobiotechnology provides an alternative efficient approach to improve such important issues in HIFU, especially for cancer therapy. This Research News presents the very recent exciting progresses on the elaborate design and fabrication of organic, inorganic, and organic/inorganic hybrid nanoparticles for enhancing the HIFU ablation efficiency against tumor tissues. It is highly expected that this Research News can arouse more extensive research enthusiasm on the development of functional nanomaterials for highly efficient HIFU-based synergistic therapy, which will give a promising noninvasive therapeutic modality for the successful cancer therapy with minimal damage to surrounding normal tissues, due to the noninvasive and site-specific therapeutic features of HIFU. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Laser restoration of flow in occluded ventricular shunts for pediatric neurosurgery

NASA Astrophysics Data System (ADS)

Christens-Barry, William A.; Guarnieri, Michael; Carson, Benjamin S.

1998-01-01

We have investigated the use of short pulses of infrared ((lambda) equals 2.09 micrometers ) light from a Ho:YAG laser to photofragment occlusions and restore flow in ventricular shunts, which provide the sole means of maintaining proper intracranial pressure in hydrocephalus patients. These experiments employed model tissues, a polymeric model compound, and patient explants in order to determine appropriate pulse energies and delivery rates for removal of occlusions material. Laser energy doses and rates of occlusion removal were established for these materials. Laser energy doses that do not damage the shunt device or surrounding tissue were identified. Optical fibers (25 ga. or smaller) can be introduced through the dome of current shunt devices and threaded to the occlusion site. Clinical application will require the continued development of an introducer tool for the transcutaneous insertion of the optical fiber into the shunt device and irrigation techniques for removing the occlusion detritus generated by photofragmentation treatment. Using this approach, a minimally invasive and benign procedure for in situ restoration of flow in occluded neurological implant devices becomes possible.

Depletion of Phagocytic Cells during Nonlethal Plasmodium yoelii Infection Causes Severe Malaria Characterized by Acute Renal Failure in Mice

PubMed Central

Terkawi, Mohamad Alaa; Nishimura, Maki; Furuoka, Hidefumi

2016-01-01

In the current study, we examined the effects of depletion of phagocytes on the progression of Plasmodium yoelii 17XNL infection in mice. Strikingly, the depletion of phagocytic cells, including macrophages, with clodronate in the acute phase of infection significantly reduced peripheral parasitemia but increased mortality. Moribund mice displayed severe pathological damage, including coagulative necrosis in liver and thrombi in the glomeruli, fibrin deposition, and tubular necrosis in kidney. The severity of infection was coincident with the increased sequestration of parasitized erythrocytes, the systematic upregulation of inflammation and coagulation, and the disruption of endothelial integrity in the liver and kidney. Aspirin was administered to the mice to minimize the risk of excessive activation of the coagulation response and fibrin deposition in the renal tissue. Interestingly, treatment with aspirin reduced the parasite burden and pathological lesions in the renal tissue and improved survival of phagocyte-depleted mice. Our data imply that the depletion of phagocytic cells, including macrophages, in the acute phase of infection increases the severity of malarial infection, typified by multiorgan failure and high mortality. PMID:26755155

Collateral damage-free debridement using 193nm ArF laser

NASA Astrophysics Data System (ADS)

Wynne, James J.; Felsenstein, Jerome M.; Trzcinski, Robert; Zupanski-Nielsen, Donna; Connors, Daniel P.

2011-03-01

Burn eschar and other necrotic areas of the skin and soft tissue are anhydrous compared to the underlying viable tissue. A 193 nm ArF excimer laser, emitting electromagnetic radiation at 6.4 eV at fluence exceeding the ablation threshold, will debride such necrotic areas. Because such radiation is strongly absorbed by aqueous chloride ions through the nonthermal process of electron photodetachment, debridement will cease when hydrated (with chloride ions) viable tissue is exposed, avoiding collateral damage to this tissue. Such tissue will be sterile and ready for further treatment, such as a wound dressing and/or a skin graft.

Mechanical and histological characterization of trachea tissue subjected to blast-type pressures

NASA Astrophysics Data System (ADS)

Butler, B. J.; Bo, C.; Tucker, A. W.; Jardine, A. P.; Proud, W. G.; Williams, A.; Brown, K. A.

2014-05-01

Injuries to the respiratory system can be a component of polytrauma in blast-loading injuries. Tissues located at air-liquid interfaces, including such tissues in the respiratory system, are particularly vulnerable to damage by blast overpressures. There is a lack of information about the mechanical and cellular responses that contribute to the damage of this class of tissues subjected to the high strain rates associated with blast loading. Here, we describe the results of dynamic blast-like pressure loading tests at high strain rates on freshly harvested ex vivo trachea tissue specimens.

Negative regulatory role of PI3-kinase in TNF-induced tumor necrosis.

PubMed

Matschurat, Susanne; Blum, Sabine; Mitnacht-Kraus, Rita; Dijkman, Henry B P M; Kanal, Levent; De Waal, Robert M W; Clauss, Matthias

2003-10-20

Tissue factor is the prime initiator of blood coagulation. Expression of tissue factor in tumor endothelial cells leads to thrombus formation, occlusion of vessels and development of hemorrhagic infarctions in the tumor tissue, often followed by regression of the tumor. Tumor cells produce endogenous vascular endothelial growth factor (VEGF), which sensitizes endothelial cells for systemically administered tumor necrosis factor alpha (TNF alpha) and synergistically enhances the TNF-induced expression of tissue factor. We have analyzed the pathways involved in the induction of tissue factor in human umbilical cord vein endothelial cells (HUVECs) after combined stimulation with TNF and VEGF. By using specific low molecular weight inhibitors, we demonstrated that protein kinase C (PKC), p44/42 and p38 mitogen-activated protein (MAP) kinases, and stress-activated protein kinase (JNK) are essentially involved in the induction of tissue factor. In contrast, the application of wortmannin, an inhibitor of phosphatidylinositol 3 (PI3)-kinase, led to strongly enhanced expression of tissue factor in TNF- and VEGF-treated cells, implicating a negative regulatory role for PI3-kinase. In vivo, the application of wortmannin promoted the formation of TNF-induced hemorrhages and intratumoral necroses in murine meth A tumors. The co-injection of wortmannin lowered the effective dose of applied TNF. Therefore, it is conceivable that the treatment of TNF-sensitive tumors with a combination of TNF and wortmannin will ensure the selective damage of the tumor endothelium and minimize the risk of systemic toxicity of TNF. TNF-treatment in combination with specific inhibition of PI3-kinase is a novel concept in anti-cancer therapy. Copyright 2003 Wiley-Liss, Inc.

Theoretical design and evaluation of endoluminal ultrasound applicators for thermal therapy of pancreatic cancer under image guidance

NASA Astrophysics Data System (ADS)

Adams, Matthew; Scott, Serena; Salgaonkar, Vasant; Sommer, Graham; Diederich, Chris

2017-03-01

An image-guided endoluminal ultrasound applicator has been proposed for palliative and potential curative thermal therapy of pancreatic tumors. By considering a directional transducer array of planar, tubular, or curvilinear transducers, this design offers the potential for fast volumetric therapy and 3D spatial control over the energy deposition profile. Treatment of pancreatic tumor tissue would be performed in a minimally invasive fashion with the applicator positioned in the gastrointestinal (GI) lumen, and sparing of the luminal wall would be achieved with a water-cooled balloon surrounding the transducers. A theoretical evaluation of this design was performed by developing a 3D acoustic and bioheat transfer model, with temperature and thermal dose solutions obtained using a FEM solver (COMSOL Multiphysics). Parametric studies were performed on a generalized anatomical model of the pancreas, tumor, and adjacent luminal wall to determine preferred transducer configurations and frequencies for maximizing lesion volume and penetration while sparing the luminal wall. Patient-specific models of pancreatic tumors were generated from CT studies and used to assess the feasibility of performing thermal ablation or hyperthermia on small (˜2 cm diameter) pancreatic head tumors with an endoluminal applicator positioned within the duodenum. Simulation results indicate lower transducer operating frequencies (1-3 MHz) are necessary to mitigate damage to the luminal wall, and a tradeoff between penetration depth and lesion volume emerges as the degree of focusing increases. For patient-specific ablation modeling of tumors within 30 mm of the luminal wall, approximately 95% of the volume could be ablated within 15 min using a planar or lightly focused transducer configuration without duodenal damage. Over 90% of the volume could be elevated above 40°C at steady state for hyperthermia applications (e.g., radiation sensitization, drug delivery) using a tubular transducer. For tumors extending deeper into the pancreas (˜35 mm), strongly focused curvilinear transducers could ablate over 80% of the tumor volume within 15 min while minimizing damage to nearby sensitive structures.

43 CFR 23.1 - Purpose.

Code of Federal Regulations, 2012 CFR

2012-10-01

... avoid, minimize, or correct damage to the environment—land, water, and air—and to avoid, minimize, or correct hazards to the public health and safety. The regulations in this part prescribe procedures to that...

43 CFR 23.1 - Purpose.

Code of Federal Regulations, 2010 CFR

2010-10-01

... avoid, minimize, or correct damage to the environment—land, water, and air—and to avoid, minimize, or correct hazards to the public health and safety. The regulations in this part prescribe procedures to that...

43 CFR 23.1 - Purpose.

Code of Federal Regulations, 2013 CFR

2013-10-01

... avoid, minimize, or correct damage to the environment—land, water, and air—and to avoid, minimize, or correct hazards to the public health and safety. The regulations in this part prescribe procedures to that...

Mitral valve surgery - minimally invasive

MedlinePlus

... flow. Your valve has developed an infection (infectious endocarditis). You have severe mitral valve prolapse that is ... function. Damage to your heart valve from infection (endocarditis). A minimally invasive procedure has many benefits. There ...

Wound ballistics 101: the mechanisms of soft tissue wounding by bullets.

PubMed

Stefanopoulos, P K; Pinialidis, D E; Hadjigeorgiou, G F; Filippakis, K N

2017-10-01

The mechanisms of soft tissue injury by bullets are reviewed, in the belief that the current incidence of firearm injuries in many urban areas necessitates an understanding of wound ballistics on the part of trauma surgeons who may not be familiar with the wounding factors involved. Review of the literature, with technical information obtained from appropriate non-medical texts. Despite numerous publications concerning the treatment of gunshot wounds, relatively few papers contain details on the mechanisms of ballistic trauma, with the main body of evidence derived from previous laboratory and animal studies which have only recently been systematically appraised. These studies have shown that in rifle injuries the main wound tract is surrounded by an area of damaged tissue as a result of the temporary cavitation induced once the bullet becomes destabilized or deformed. On the other hand, the more commonly encountered non-deforming handgun bullets cause damage limited to the bullet's path, mainly as a result of localized crush injury. The bullet's construction and ballistic behavior within tissue determine to what extent the previously overestimated velocity factor may influence wound severity. The damage produced from temporary cavitation depends on the tensile properties of the tissues involved, and in high-energy injuries may lead to progressive muscle tissue necrosis. Therefore, the term "high-energy" should be reserved for those injuries with substantial tissue damage extending beyond the visible wound tract.

Dietary supplementation with the microalga Galdieria sulphuraria (Rhodophyta) reduces prolonged exercise-induced oxidative stress in rat tissues.

PubMed

Carfagna, Simona; Napolitano, Gaetana; Barone, Daniela; Pinto, Gabriele; Pollio, Antonino; Venditti, Paola

2015-01-01

We studied the effects of ten-day 1% Galdieria sulphuraria dietary supplementation on oxidative damage and metabolic changes elicited by acute exercise (6-hour swimming) determining oxygen consumption, lipid hydroperoxides, protein bound carbonyls in rat tissue (liver, heart, and muscle) homogenates and mitochondria, tissue glutathione peroxidase and glutathione reductase activities, glutathione content, and rates of H2O2 mitochondrial release. Exercise increased oxidative damage in tissues and mitochondria and decreased tissue content of reduced glutathione. Moreover, it increased State 4 and decreased State 3 respiration in tissues and mitochondria. G. sulphuraria supplementation reduced the above exercise-induced variations. Conversely, alga supplementation was not able to modify the exercise-induced increase in mitochondrial release rate of hydrogen peroxide and in liver and heart antioxidant enzyme activities. The alga capacity to reduce lipid oxidative damage without reducing mitochondrial H2O2 release can be due to its high content of C-phycocyanin and glutathione, which are able to scavenge peroxyl radicals and contribute to phospholipid hydroperoxide metabolism, respectively. In conclusion, G. sulphuraria ability to reduce exercise-linked oxidative damage and mitochondrial dysfunction makes it potentially useful even in other conditions leading to oxidative stress, including hyperthyroidism, chronic inflammation, and ischemia/reperfusion.

Clinical effects of the use of a bipolar vessel sealing device for soft palate resection and tonsillectomy in dogs, with histological assessment of resected tonsillar tissue.

PubMed

Cook, D A; Moses, P A; Mackie, J T

2015-12-01

To investigate whether soft palate resection and tonsillectomy with a bipolar vessel sealing device (BVSD) improves clinical respiratory score. To document histopathological changes to tonsillar tissue following removal with a BVSD. Case series of 22 dogs with clinical signs of upper respiratory obstruction related to brachycephalic airway syndrome. Soft palate and tonsils were removed using a BVSD. Alarplasty and saccullectomy were also performed if indicated. A clinical respiratory score was assigned preoperatively, 24-h postoperatively and 5 weeks postoperatively. Excised tonsillar samples were measured and then assessed histologically for depth of tissue damage deemed to be caused by the device. Depth of tissue damage was compared between two power settings of the device. Soft palate resection and tonsillectomy with a BVSD lead to a significant improvement in respiratory scores following surgery. Depth of tissue damage was significantly less for power setting 1 compared with power setting 2. Using power setting 1, median calculated depth of tonsillar tissue damage was 3.4 mm (range 1.2-8.0). One dog experienced major complications. Soft palate resection and tonsillectomy with a BVSD led to significant improvement in clinical respiratory score. © 2015 Australian Veterinary Association.

Dietary Supplementation with the Microalga Galdieria sulphuraria (Rhodophyta) Reduces Prolonged Exercise-Induced Oxidative Stress in Rat Tissues

PubMed Central

Carfagna, Simona; Napolitano, Gaetana; Barone, Daniela; Pinto, Gabriele; Venditti, Paola

2015-01-01

We studied the effects of ten-day 1% Galdieria sulphuraria dietary supplementation on oxidative damage and metabolic changes elicited by acute exercise (6-hour swimming) determining oxygen consumption, lipid hydroperoxides, protein bound carbonyls in rat tissue (liver, heart, and muscle) homogenates and mitochondria, tissue glutathione peroxidase and glutathione reductase activities, glutathione content, and rates of H2O2 mitochondrial release. Exercise increased oxidative damage in tissues and mitochondria and decreased tissue content of reduced glutathione. Moreover, it increased State 4 and decreased State 3 respiration in tissues and mitochondria. G. sulphuraria supplementation reduced the above exercise-induced variations. Conversely, alga supplementation was not able to modify the exercise-induced increase in mitochondrial release rate of hydrogen peroxide and in liver and heart antioxidant enzyme activities. The alga capacity to reduce lipid oxidative damage without reducing mitochondrial H2O2 release can be due to its high content of C-phycocyanin and glutathione, which are able to scavenge peroxyl radicals and contribute to phospholipid hydroperoxide metabolism, respectively. In conclusion, G. sulphuraria ability to reduce exercise-linked oxidative damage and mitochondrial dysfunction makes it potentially useful even in other conditions leading to oxidative stress, including hyperthyroidism, chronic inflammation, and ischemia/reperfusion. PMID:25874021

Hazard Mitigation Assistance Programs Available to Water and Wastewater Utilities

EPA Pesticide Factsheets

You can prevent damage to your utility before it occurs. Utilities can implement mitigation projects to better withstand a natural disaster, minimize damage and rapidly recover from disruptions to service.

Feasibility of chemohyperthermia with docetaxel-embedded magnetoliposomes as minimally invasive local treatment for cancer.

PubMed

Yoshida, Motohira; Watanabe, Yuji; Sato, Mitsunori; Maehara, Tsunehiro; Aono, Hiromichi; Naohara, Takashi; Hirazawa, Hideyuki; Horiuchi, Atsushi; Yukumi, Shungo; Sato, Koichi; Nakagawa, Hiromichi; Yamamoto, Yuji; Sugishita, Hiroki; Kawachi, Kanji

2010-04-15

Hyperthermia is a minimally invasive approach to cancer treatment, but it is difficult to heat only the tumor without damaging surrounding tissue. To solve this problem, we studied the effectiveness of chemohyperthermia with docetaxel-embedded magnetoliposomes (DMLs) and an applied alternating current (AC) magnetic field. Human MKN45 gastric cancer cells were implanted in the hind limb of Balb-c/nu/nu mice. Various concentrations of docetaxel-embedded DMLs were injected into the tumors and exposed to an AC magnetic field (n = 6, each). For comparison with hyperthermia alone, magnetite-loaded liposome (ML)-injected tumors were exposed to an AC magnetic field. Furthermore, the results of DML without AC treatment and docetaxel diluted into PBS with AC treatment were also compared (n = 10, each). Tumor surface temperature was maintained between 42 and 43 degrees C. Tumor volume was reduced in the DML group with a docetaxel concentration > 56.8 microg/ml, while a docetaxel concentration > 568.5 microg/ml was required for tumor reduction without hyperthermia. Statistically significant differences in tumor volume and survival rate were observed between the DML group exposed to the magnetic field and the other groups. The tumor disappeared in 3 mice in the DML group exposed to the magnetic field; 2 mice survived over 6 months after treatment, whereas all mice of the other groups died by 15 weeks. Histologically, hyperthermia with DML damaged tumor cells and DML diffused homogeneously. To the best of our knowledge, this is the first report to show that hyperthermia using chemotherapeutic agent-embedded magnetoliposomes has an anticancer effect.

Controlled circumferential renal sympathetic denervation with preservation of the renal arterial wall using intraluminal ultrasound: a next-generation approach for treating sympathetic overactivity.

PubMed

Sakakura, Kenichi; Roth, Austin; Ladich, Elena; Shen, Kai; Coleman, Leslie; Joner, Michael; Virmani, Renu

2015-02-01

The Paradise Ultrasound Renal Denervation System is a next-generation catheter-based device which was used to investigate whether the target ablation area can be controlled by changing ultrasound energy and duration to optimise nerve injury while preventing damage to the arterial wall. Five ultrasound doses were tested in a thermal gel model. Catheter-based ultrasound denervation was performed in 15 swine (29 renal arteries) to evaluate five different doses in vivo, and animals were euthanised at seven days for histopathologic assessment. In the gel model, the peak temperature was highest in the low power-long duration (LP-LD) dose, followed by the mid-low power-mid duration (MLP-MD) dose and the mid-high power-short duration (MHP-SD) dose, and lowest in the mid power-short duration (MP-SD) dose and the high power-ultra short duration (HP-USD) dose. In the animal study, total ablation area was significantly greater in the LP-LD group, followed by the MLP-MD group, and it was least in the HP-USD, MP-SD and MHP-SD groups (p=0.02). Maximum distance was significantly greater in the LP-LD group, followed by the MLP-MD group, the MHP-SD group, and the HP-USD group, and shortest in the MP-SD group (p=0.007). The short spare distance was not different among the five groups (p=0.38). Renal artery damage was minimal, while preserving significant nerve damage in all groups. The Paradise Ultrasound Renal Denervation System is a controllable system where total ablation area and depth of ablation can be optimised by changing ultrasound power and duration while sparing renal arterial tissue damage but allowing sufficient peri-arterial nerve damage.

A common carcinogen benzo[a]pyrene causes p53 overexpression in mouse cervix via DNA damage.

PubMed

Gao, Meili; Li, Yongfei; Sun, Ying; Long, Jiangang; Kong, Yu; Yang, Shuiyun; Wang, Yili

2011-09-18

Benzo[a]pyrene (BaP) is cytotoxic and/or genotoxic to lung, stomach and skin tissue in the body. However, the effect of BaP on cervical tissue remains unclear. The present study detected DNA damage and the expression of the p53 gene in BaP-induced cervical tissue in female mice. Animals were intraperitoneally injected and orally gavaged with BaP at the doses of 2.5, 5, and 10mg/kg twice a week for 14 weeks. The single-cell gel electrophoresis (SCGE) assay was used to detect the DNA damage. Immunohistochemistry (IHC) and in situ hybridization (ISH) were used to detect the expression of p53 protein and p53 mRNA, respectively. The results showed that BaP induced a significant and dose-dependent increase of the number of cells with DNA damaged and the tail length as well as Comet tail moment in cervical tissue. The expression level of p53 protein and mRNA was increased. The results demonstrate that BaP may show toxic effect on the cervix by increasing DNA damage and the expression of the p53 gene. Copyright © 2011 Elsevier B.V. All rights reserved.

Histopomorphic Evaluation of Radiofrequency Mediated Débridement Chondroplasty

PubMed Central

Ganguly, Kumkum; McRury, Ian D; Goodwin, Peter M; Morgan, Roy E; Augé II, Wayne K

2010-01-01

The use of radiofrequency devices has become widespread for surgical ablation procedures. When ablation devices have been deployed in treatment settings requiring tissue preservation like débridement chondroplasty, adoption has been limited due to the collateral damage caused by these devices in healthy tissue surrounding the treatment site. Ex vivo radiofrequency mediated débridement chondroplasty was performed on osteochondral specimens demonstrating surface fibrillation obtained from patients undergoing knee total joint replacement. Three radiofrequency systems designed to perform débridement chondroplasty were tested each demonstrating different energy delivery methods: monopolar ablation, bipolar ablation, and non-ablation energy. Treatment outcomes were compared with control specimens as to clinical endpoint and histopomorphic characteristics. Fibrillated cartilage was removed in all specimens; however, the residual tissue remaining at the treatment site displayed significantly different characteristics attributable to radiofrequency energy delivery method. Systems that delivered ablation-based energies caused tissue necrosis and collateral damage at the treatment site including corruption of cartilage Superficial and Transitional Zones; whereas, the non-ablation system created a smooth articular surface with Superficial Zone maintenance and without chondrocyte death or tissue necrosis. The mechanism of radiofrequency energy deposition upon tissues is particularly important in treatment settings requiring tissue preservation. Ablation-based device systems can cause a worsened state of articular cartilage from that of pre-treatment. Non-ablation energy can be successful in modifying/preconditioning tissue during débridement chondroplasty without causing collateral damage. Utilizing a non-ablation radiofrequency system provides the ability to perform successful débridement chondroplasty without causing additional articular cartilage tissue damage and may allow for other cartilage intervention success. PMID:20721322