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  1. Patterns and Variations in Microvascular Decompression for Trigeminal Neuralgia

    PubMed Central

    TODA, Hiroki; GOTO, Masanori; IWASAKI, Koichi

    2015-01-01

    Microvascular decompression (MVD) is a highly effective surgical treatment for trigeminal neuralgia (TN). Although there is little prospective clinical evidence, accumulated observational studies have demonstrated the benefits of MVD for refractory TN. In the current surgical practice of MVD for TN, there have been recognized patterns and variations in surgical anatomy and various decompression techniques. Here we provide a stepwise description of surgical procedures and relevant anatomical characteristics, as well as procedural options. PMID:25925756

  2. Management of Bilateral Hemifacial Spasm with Microvascular Decompression.

    PubMed

    Dou, Ning-Ning; Zhong, Jun; Liu, Ming-Xing; Xia, Lei; Sun, Hui; Li, Bin; Li, Shi-Ting

    2016-03-01

    Bilateral hemifacial spasm (HFS) is very rare. The literature contains only 32 clinical reports. Although microvascular decompression (MVD) is widely accepted as effective therapy for HFS, the etiology and surgical treatment of bilateral HFS are seldom addressed. We report our experience with MVD for patients with bilateral HFS. This retrospective report included 10 patients with bilateral HFS. All patients underwent MVD 1 or 2 times and were followed for 5-92 months. The clinical data were retrospectively analyzed. The etiology and treatment strategies were discussed. Spasm stopped completely on the operative side in all 10 patients. Symptoms on the other side also resolved in 3 patients, improved in 1 patient, and did not improve at all in 6 patients. Of the 6 patients with no improvement, 5 underwent another MVD on the contralateral side within 1 year and experienced relief of symptoms, and 1 patient refused the surgery. The neurovascular conflict was found in all the operations. During the follow-up period, no complications of hearing loss or facial palsy and no recurrence were observed. Vascular compression was the cause of bilateral HFS in our patients, and MVD relieved the symptoms. Thus, we recommend MVD for patients with bilateral HFS. A crowded cerebellopontine angle space and easy attrition of the neurovascular interfaces may play important roles in the occurrence of bilateral HFS. For some patients, 1 MVD can resolve bilateral symptoms. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Microvascular decompression or neuromodulation in patients with SUNCT and trigeminal neurovascular conflict?

    PubMed

    Hassan, Samih; Lagrata, Susie; Levy, Andrew; Matharu, Manjit; Zrinzo, Ludvic

    2018-02-01

    Objectives To assess the effectiveness of neuromodulation and trigeminal microvascular decompression (MVD) in patients with medically-intractable short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT). Methods Two patients with medically refractory SUNCT underwent MVD following beneficial but incomplete response to neuromodulation (occipital nerve stimulation and deep brain stimulation). MRI confirmed neurovascular conflict with the ipsilateral trigeminal nerve in both patients. Results Although neuromodulation provided significant benefit, it did not deliver complete relief from pain and management required numerous postoperative visits with adjustment of medication and stimulation parameters. Conversely, MVD was successful in eliminating symptoms of SUNCT in both patients with no need for further medical treatment or neuromodulation. Conclusion Neuromodulation requires expensive hardware and lifelong follow-up and maintenance. These case reports highlight that microvascular decompression may be preferable to neuromodulation in the subset of SUNCT patients with ipsilateral neurovascular conflict.

  4. Correlation Between Cerebellar Retraction and Hearing Loss After Microvascular Decompression for Hemifacial Spasm: A Prospective Study.

    PubMed

    Li, Ning; Zhao, Wei-Guo; Pu, Chun-Hua; Yang, Wen-Lei

    2017-06-01

    This study prospectively investigated the relationship between cerebellar retraction factors measured on preoperative magnetic resonance and the development of postoperative hearing loss and evaluated their potential role in predicting the possibility of hearing loss after microvascular decompression (MVD) for hemifacial spasm (HFS). The study included 110 patients clinically diagnosed with primary HFS who underwent MVD in our department. The cerebellar retraction factors were quantitatively measured on preoperative magnetic resonance. Associations of cerebellar retraction and other risk factors with postoperative hearing loss were analyzed. Eleven patients (10%) developed nonserviceable hearing loss after MVD. Compared with the group without hearing loss, the cerebellar retraction distance and depth of the group with hearing loss were significantly greater (P < 0.05). Multivariate logistic regression analysis showed that greater cerebellar retraction depth was significantly associated with the higher incidence of postoperative hearing loss (P < 0.05). The results in this study strongly suggested the correlation between the cerebellar retraction depth and the possibility of hearing loss after MVD for HFS. In addition, cerebellar retraction depth could be considered as a useful tool to predict the risk of post-MVD hearing loss. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Closed-Suction Drainage and Cerebrospinal Fluid Leakage Following Microvascular Decompression : A Retrospective Comparison Study

    PubMed Central

    Kim, Young-Hoon; Kim, Chae-Yong; Oh, Chang Wan

    2013-01-01

    Objective We performed this study to investigate whether the use of closed-suction drainage following microvascular decompression (MVD) causes cerebrospinal fluid (CSF) leakage. Methods Between 2004 and 2011, a total of 157 patients with neurovascular compression were treated with MVD. MVD was performed for hemifacial spasm in 150 (95.5%) cases and for trigeminal neuralgia in 7 (4.5%) cases. The mean age of the patients was 49.8±9.6 years (range, 20-69). Dural substitutes were used in 44 (28.0%) patients. Ninety-two patients (58.6%) were underwent a 4-5 cm craniotomy using drainage (drainage group), and 65 (41.4%) did a small 2-2.5 cm retromastoid craniectomy without closed-suction drainage (no-drainage group). Results Eleven (7.0%) patients experienced CSF leakage following MVD based on the criteria of this study; all of these patients were in the drainage group. In the unadjusted analyses, the incidence of CSF leakage was significantly related with the use of closed-suction drainage following MVD (12.0% in the drainage group vs. 0% in the no-drainage group, respectively; p=0.003; Fisher's exact test). Those who received dural substitutes and the elderly (cut-off value=60 years) exhibited a tendency to develop CSF leakage (p=0.075 and p=0.090, respectively; Fisher's exact test). In the multivariate analysis, only the use of closed-suction drainage was significantly and independently associated with the development of CSF leakage following MVD (odds ratio=9.900; 95% confidence interval, 1.418 to infinity; p=0.017). Conclusion The use of closed-suction drainage following MVD appears to be related to the development of CSF leakage. PMID:24175025

  6. Microvascular Decompression for Trigeminal Neuralgia: Technical Refinement for Complication Avoidance.

    PubMed

    Tomasello, Francesco; Esposito, Felice; Abbritti, Rosaria V; Angileri, Filippo F; Conti, Alfredo; Cardali, Salvatore M; La Torre, Domenico

    2016-10-01

    Microvascular decompression (MVD) represents the most effective and safe surgical option for the treatment of trigeminal neuralgia since it was first popularized by Jannetta 50 years ago. Despite several advances, complications such as cerebellar and vascular injury, hearing loss, muscular atrophy, cerebrospinal fluid (CSF) leak, postoperative cutaneous pain, and sensory disturbances still occur and may negatively affect the outcome. We propose some technical nuances of the surgical procedure that were used in our recent series. We used a novel hockey stick-shaped retromastoid skin incision, preserving the major nerves of the occipital and temporal areas. Microsurgical steps were performed without the use of retractors. CSF leakage was prevented with a watertight dural closure and multilayer osteodural reconstruction. The refined surgical steps were perfected in the last consecutive 15 cases of our series. In these cases we did not record any cutaneous pain, sensory disturbances, or CSF leakage. The average diameter of the craniectomy was 18 mm. No patient reported major complications related to the intradural microsurgical maneuvers. In all cases the neurovascular conflict was found and solved with a good outcome in terms of pain disappearance. Our minimally invasive approach was demonstrated to guarantee an optimal exposure of the cerebellopontine angle and minimize the rate of complications related to skin incision and muscular dissection, microsurgical steps, and closure. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Tenth case of bilateral hemifacial spasm treated by microvascular decompression: Review of the pathophysiology

    PubMed Central

    da Silva Martins, Warley Carvalho; de Albuquerque, Lucas Alverne Freitas; de Carvalho, Gervásio Teles Cardoso; Dourado, Jules Carlos; Dellaretti, Marcos; de Sousa, Atos Alves

    2017-01-01

    Background: Bilateral hemifacial spasm (BHFS) is a rare neurological syndrome whose diagnosis depends on excluding other facial dyskinesias. We present a case of BHFS along with a literature review. Methods: A 64-year-old white, hypertense male reported involuntary left hemiface contractions in 2001 (aged 50). In 2007, right hemifacial symptoms appeared, without spasm remission during sleep. Botulinum toxin type A application produced partial temporary improvement. Left microvascular decompression (MVD) was performed in August 2013, followed by right MVD in May 2014, with excellent results. Follow-up in March 2016 showed complete cessation of spasms without medication. Results: The literature confirms nine BHFS cases bilaterally treated by MVD, a definitive surgical option with minimal complications. Regarding HFS pathophysiology, ectopic firing and ephaptic transmissions originate in the root exit zone (REZ) of the facial nerve, due to neurovascular compression (NVC), orthodromically stimulate facial muscles and antidromically stimulate the facial nerve nucleus; this hyperexcitation continuously stimulates the facial muscles. These activated muscles can trigger somatosensory afferent skin nerve impulses and neuromuscular spindles from the trigeminal nerve, which, after transiting the Gasser ganglion and trigeminal nucleus, reach the somatosensory medial posterior ventral nucleus of the contralateral thalamus as well as the somatosensory cortical area of the face. Once activated, this area can stimulate the motor and supplementary motor areas (extrapyramidal and basal ganglia system), activating the motoneurons of the facial nerve nucleus and peripherally stimulating the facial muscles. Conclusions: We believe that bilateral MVD is the best approach in cases of BHFS. PMID:29026661

  8. Persistent hemifacial spasm after microvascular decompression: a risk assessment model.

    PubMed

    Shah, Aalap; Horowitz, Michael

    2017-06-01

    Microvascular decompression (MVD) for hemifacial spasm (HFS) provides resolution of disabling symptoms such as eyelid twitching and muscle contractions of the entire hemiface. The primary aim of this study was to evaluate the predictive value of patient demographics and spasm characteristics on long-term outcomes, with or without intraoperative lateral spread response (LSR) as an additional variable in a risk assessment model. A retrospective study was undertaken to evaluate the associations of pre-operative patient characteristics, as well as intraoperative LSR and need for a staged procedure on the presence of persistent or recurrent HFS at the time of hospital discharge and at follow-up. A risk assessment model was constructed with the inclusion of six clinically or statistically significant variables from the univariate analyses. A receiving operator characteristic curve was generated, and area under the curve was calculated to determine the strength of the predictive model. A risk assessment model was first created consisting of significant pre-operative variables (Model 1) (age >50, female gender, history of botulinum toxin use, platysma muscle involvement). This model demonstrated borderline predictive value for persistent spasm at discharge (AUC .60; p=.045) and fair predictive value at follow-up (AUC .75; p=.001). Intraoperative variables (e.g. LSR persistence) demonstrated little additive value (Model 2) (AUC .67). Patients with a higher risk score (three or greater) demonstrated greater odds of persistent HFS at the time of discharge (OR 1.5 [95%CI 1.16-1.97]; p=.035), as well as greater odds of persistent or recurrent spasm at the time of follow-up (OR 3.0 [95%CI 1.52-5.95]; p=.002) Conclusions: A risk assessment model consisting of pre-operative clinical characteristics is useful in prognosticating HFS persistence at follow-up.

  9. Utility of Brainstem Trigeminal Evoked Potentials in Patients With Primary Trigeminal Neuralgia Treated by Microvascular Decompression.

    PubMed

    Zhu, Jin; Zhang, Xin; Zhao, Hua; Tang, Yin-Da; Ying, Ting-Ting; Li, Shi-Ting

    2017-09-01

    To investigate the characteristics of brainstem trigeminal evoked potentials (BTEP) waveform in patients with and without trigeminal neuralgia (TN), and to discuss the utility of BTEP in patients with primary TN treated by microvascular decompression (MVD). A retrospective review of 43 patients who underwent BTEP between January 2016 and June 2016, including 33 patients with TN who underwent MVD and 10 patients without TN. Brainstem trigeminal evoked potentials characteristics of TN and non-TN were summarized, in particular to compare the BTEP changes between pre- and post-MVD, and to discover the relationship between BTEP changes and surgical outcome. Brainstem trigeminal evoked potentials can be recorded in patients without trigeminal neuralgia. Abnormal BTEP could be recorded when different branches were stimulated. After decompression, the original W2, W3 disappeared and then replaced by a large wave in most patients, or original wave poorly differentiated improved in some patients, showed as shorter latency and (or) amplitude increased. Brainstem trigeminal evoked potentials waveform of healthy side in patients with trigeminal neuralgia was similar to the waveform of patients without TN. In 3 patients, after decompression the W2, W3 peaks increased, and the latency, duration, IPLD did not change significantly. Until discharge, 87.9% (29/33) of the patients presented complete absence of pain without medication (BNI I) and 93.9% (31/33) had good pain control without medication (BNI I-II). Brainstem trigeminal evoked potentials can reflect the conduction function of the trigeminal nerve to evaluate the functional level of the trigeminal nerve conduction pathway. The improvement and restoration of BTEP waveforms are closely related to the postoperative curative effect.

  10. Preoperative evaluation of neurovascular relationships for microvascular decompression in the cerebellopontine angle in a virtual reality environment.

    PubMed

    Du, Zhuo-Ying; Gao, Xiang; Zhang, Xiao-Luo; Wang, Zhi-Qiu; Tang, Wei-Jun

    2010-09-01

    In this paper the authors' goal was to evaluate the feasibility and efficacy of a virtual reality (VR) system in preoperative planning for microvascular decompression (MVD) procedures treating idiopathic trigeminal neuralgia and hemifacial spasm. The system's role in surgical simulation and training was also assessed. Between May 2008 and April 2009, the authors used the Dextroscope system to visualize the neurovascular complex and simulate MVD in the cerebellopontine angle in a VR environment in 16 patients (6 patients had trigeminal neuralgia and 10 had hemifacial spasm). Reconstructions were carried out 2-3 days before MVD. Images were printed in a red-blue stereoscopic format for teaching and discussion and were brought into the operating room to be compared with real-time intraoperative findings. The VR environment was a powerful aid for spatial understanding of the neurovascular relationship in MVD for operating surgeons and trainees. Through an initial series of comparison/confirmation experiences, the senior neurosurgeon became accustomed to the system. He could predict intraoperative problems and simulate surgical maneuvering, which increased his confidence in performing the procedure. The Dextroscope system is an easy and rapid method to create a stereoscopic neurovascular model for MVD that is highly concordant with intraoperative findings. It effectively shortens the learning curve and adds to the surgeon's confidence.

  11. Quantitative study of the correlation between cerebellar retraction factors and hearing loss following microvascular decompression for hemifacial spasm.

    PubMed

    Li, Ning; Zhao, Wei-Guo; Pu, Chun-Hua; Yang, Wen-Lei

    2018-01-01

    This prospective study quantitatively measured the cerebellar retraction factors, including retraction distance, depth and duration, and evaluated their potential relationship to the development of hearing loss after microvascular decompression (MVD) for hemifacial spasm (HFS). One hundred ten patients with primary HFS who underwent MVD in our department were included into this study. The cerebellar retraction factors were quantitatively measured on preoperative MR and timed during MVD. Associations of cerebellar retraction and other factors to postoperative hearing loss were analyzed. Eleven (10%) patients developed hearing loss after MVD. Compared with the group without hearing loss, the cerebellar retraction distance, depth and duration of the group with hearing loss were significantly greater (p < 0.05). Multivariate regression analysis showed that greater cerebellar retraction depth and longer retraction duration were significantly associated with a higher incidence of postoperative hearing impairment (p < 0.05). This study strongly suggested a correlation between the cerebellar retraction factors, especially retraction depth and duration, and possibility of hearing loss following MVD for HFS.

  12. Hydrocephalus: an underrated long-term complication of microvascular decompression for trigeminal neuralgia. A single institute experience.

    PubMed

    Muratorio, Francesco; Tringali, G; Levi, V; Ligarotti, G K I; Nazzi, V; Franzini, A A

    2016-11-01

    Hydrocephalus is a common complication of posterior fossa surgery, but its real incidence after microvascular decompression (MVD) for idiopathic trigeminal neuralgia (TN) still remains unclear. The aim of this study was to focus on the potential association between MVD and hydrocephalus as a surgery-related complication. All patients who underwent MVD procedure for idiopathic TN at our institute between 2009 and 2014 were reviewed to search for early or late postoperative hydrocephalus. There were 259 consecutive patients affected by idiopathic TN who underwent MVD procedure at our institution between 2009 and 2014 (113 men, 146 women; mean age 59 years, range 30-87 years; mean follow-up 40.92 months, range 8-48 months). Nine patients (3.47 %) developed communicating hydrocephalus after hospital discharge and underwent standard ventriculo-peritoneal shunt. No cases of acute hydrocephalus were noticed. Our study suggests that late communicating hydrocephalus may be an underrated potential long-term complication of MVD surgery.

  13. Real-time intraoperative monitoring of brainstem auditory evoked potentials during microvascular decompression for hemifacial spasm.

    PubMed

    Joo, Byung-Euk; Park, Sang-Ku; Cho, Kyung-Rae; Kong, Doo-Sik; Seo, Dae-Won; Park, Kwan

    2016-11-01

    OBJECTIVE The aim of this study was to define a new protocol for intraoperative monitoring (IOM) of brainstem auditory evoked potentials (BAEPs) during microvascular decompression (MVD) surgery to treat hemifacial spasm (HFS) and to evaluate the usefulness of this new protocol to prevent hearing impairment. METHODS To define the optimal stimulation rate, estimate the number of trials to be averaged, and identify useful warning criteria in IOM of BAEPs, the authors performed a preliminary study of 13 patients with HFS in 2010. They increased the stimulation rate from 10.1 Hz/sec to 100.1 Hz/sec by 10-Hz increments, and they elevated the average time from 100 times to 1000 times by 100-unit increments at a fixed stimulus rate of 43.9 Hz. After defining the optimal stimulation rate and the number of trials that needed to be averaged for IOM of BAEPs, they also identified the useful warning criteria for this protocol for MVD surgery. From January to December 2013, 254 patients with HFS underwent MVD surgery following the new IOM of BAEPs protocol. Pure-tone audiometry and speech discrimination scoring were performed before surgery and 1 week after surgery. To evaluate the usefulness of the new protocol, the authors compared the incidence of postoperative hearing impairment with the results from the group that underwent MVD surgery prior to the new protocol. RESULTS Through a preliminary study, the authors confirmed that it was possible to obtain a reliable wave when using a stimulation rate of 43.9 Hz/sec and averaging 400 trials. Only a Wave V amplitude loss > 50% was useful as a warning criterion when using the new protocol. A reliable BAEP could be obtained in approximately 9.1 seconds. When the new protocol was used, 2 patients (0.8%) showed no recovery of Wave V amplitude loss > 50%, and only 1 of those 2 patients (0.39%) ultimately had postoperative hearing impairment. When compared with the outcomes in the pre-protocol group, hearing impairment incidence

  14. Microvascular decompression for trigeminal neuralgia: comments on a series of 250 cases, including 10 patients with multiple sclerosis.

    PubMed

    Broggi, G; Ferroli, P; Franzini, A; Servello, D; Dones, I

    2000-01-01

    To examine surgical findings and results of microvascular decompression (MVD) for trigeminal neuralgia (TN), including patients with multiple sclerosis, to bring new insight about the role of microvascular compression in the pathogenesis of the disorder and the role of MVD in its treatment. Between 1990 and 1998, 250 patients affected by trigeminal neuralgia underwent MVD in the Department of Neurosurgery of the "Istituto Nazionale Neurologico C Besta" in Milan. Limiting the review to the period 1991-6, to exclude the "learning period" (the first 50 cases) and patients with less than 1 year follow up, surgical findings and results were critically analysed in 148 consecutive cases, including 10 patients with multiple sclerosis. Vascular compression of the trigeminal nerve was found in all cases. The recurrence rate was 15.3% (follow up 1-7 years, mean 38 months). In five of 10 patients with multiple sclerosis an excellent result was achieved (follow up 12-39 months, mean 24 months). Patients with TN for more than 84 months did significantly worse than those with a shorter history (p<0.05). There was no mortality and most complications occurred in the learning period. Surgical complications were not related to age of the patients. Aetiopathogenesis of trigeminal neuralgia remains a mystery. These findings suggest a common neuromodulatory role of microvascular compression in both patients with or without multiple sclerosis rather than a direct causal role. MVD was found to be a safe and effective procedure to relieve typical TN in patients of all ages. It should be proposed as first choice surgery to all patients affected by TN, even in selected cases with multiple sclerosis, to give them the opportunity of pain relief without sensory deficits.

  15. Microvascular decompression for trigeminal neuralgia: comments on a series of 250 cases, including 10 patients with multiple sclerosis

    PubMed Central

    Broggi, G.; Ferroli, P.; Franzini, A.; Servello, D.; Dones, I.

    2000-01-01

    OBJECTIVE—To examine surgical findings and results of microvascular decompression (MVD) for trigeminal neuralgia (TN), including patients with multiple sclerosis, to bring new insight about the role of microvascular compression in the pathogenesis of the disorder and the role of MVD in its treatment.
METHODS—Between 1990 and 1998, 250 patients affected by trigeminal neuralgia underwent MVD in the Department of Neurosurgery of the "Istituto Nazionale Neurologico C Besta" in Milan. Limiting the review to the period 1991-6, to exclude the "learning period" (the first 50 cases) and patients with less than 1 year follow up, surgical findings and results were critically analysed in 148 consecutive cases, including 10 patients with multiple sclerosis.
RESULTS—Vascular compression of the trigeminal nerve was found in all cases. The recurrence rate was 15.3% (follow up 1-7 years, mean 38 months). In five of 10 patients with multiple sclerosis an excellent result was achieved (follow up 12-39 months, mean 24months). Patients with TN for more than 84 months did significantly worse than those with a shorter history (p<0.05). There was no mortality and most complications occurred in the learning period. Surgical complications were not related to age of the patients.
CONCLUSIONS—Aetiopathogenesis of trigeminal neuralgia remains a mystery. These findings suggest a common neuromodulatory role of microvascular compression in both patients with or without multiple sclerosis rather than a direct causal role. MVD was found to be a safe and effective procedure to relieve typical TN in patients of all ages. It should be proposed as first choice surgery to all patients affected by TN, even in selected cases with multiple sclerosis, to give them the opportunity of pain relief without sensory deficits. 

 PMID:10601403

  16. Pharmacological versus microvascular decompression approaches for the treatment of trigeminal neuralgia: clinical outcomes and direct costs

    PubMed Central

    Lemos, Laurinda; Alegria, Carlos; Oliveira, Joana; Machado, Ana; Oliveira, Pedro; Almeida, Armando

    2011-01-01

    In idiopathic trigeminal neuralgia (TN) the neuroimaging evaluation is usually normal, but in some cases a vascular compression of trigeminal nerve root is present. Although the latter condition may be referred to surgery, drug therapy is usually the first approach to control pain. This study compared the clinical outcome and direct costs of (1) a traditional treatment (carbamazepine [CBZ] in monotherapy [CBZ protocol]), (2) the association of gabapentin (GBP) and analgesic block of trigger-points with ropivacaine (ROP) (GBP+ROP protocol), and (3) a common TN surgery, microvascular decompression of the trigeminal nerve (MVD protocol). Sixty-two TN patients were randomly treated during 4 weeks (CBZ [n = 23] and GBP+ROP [n = 17] protocols) from cases of idiopathic TN, or selected for MVD surgery (n = 22) due to intractable pain. Direct medical cost estimates were determined by the price of drugs in 2008 and the hospital costs. Pain was evaluated using the Numerical Rating Scale (NRS) and number of pain crises; the Hospital Anxiety and Depression Scale, Sickness Impact Profile, and satisfaction with treatment and hospital team were evaluated. Assessments were performed at day 0 and 6 months after the beginning of treatment. All protocols showed a clinical improvement of pain control at month 6. The GBP+ROP protocol was the least expensive treatment, whereas surgery was the most expensive. With time, however, GBP+ROP tended to be the most and MVD the least expensive. No sequelae resulted in any patient after drug therapies, while after MDV surgery several patients showed important side effects. Data reinforce that, (1) TN patients should be carefully evaluated before choosing therapy for pain control, (2) different pharmacological approaches are available to initiate pain control at low costs, and (3) criteria for surgical interventions should be clearly defined due to important side effects, with the initial higher costs being strongly reduced with time. PMID:21941455

  17. Reduced CSF leak in complete calvarial reconstructions of microvascular decompression craniectomies using calcium phosphate cement.

    PubMed

    Eseonu, Chikezie I; Goodwin, C Rory; Zhou, Xin; Theodros, Debebe; Bender, Matthew T; Mathios, Dimitrios; Bettegowda, Chetan; Lim, Michael

    2015-12-01

    Calcium phosphate cement provides a biomaterial that can be used for calvarial reconstruction in a retrosigmoid craniectomy for microvascular decompression (MVD). This study evaluates the outcomes of postoperative CSF leak and wound infection for patients undergoing a complete cranioplasty using calcium phosphate cement versus incomplete cranioplasty using polyethylene titanium mesh following a retrosigmoid craniectomy for MVD. The authors evaluated 211 cases involving patients who underwent first-time retrosigmoid craniectomies performed by a single attending surgeon fortrigeminal neuralgia from October 2008 to June 2014. From this patient population, 111 patients underwent calvarial reconstruction after retrosigmoid craniectomy using polyethylene titanium mesh, and 100 patients had reconstructions using calcium phosphate cement. A Pearson's chi-square test was used to compare postoperative complications of CSF leak and wound infection in these 2 types of cranioplasties. The polyethylene titanium mesh group included 5 patients (4.5%) with postoperative CSF leak or pseudomeningocele and 3 patients (2.7%) with wound infections. In the calcium phosphate cement group, no patients had a CSF leak, and 2 patients (2%) had wound infections. This represented a statistically significant reduction of postoperative CSF leak in patients who underwent calcium phosphate reconstructions of their calvarial defect compared with those who underwent polyethylene titanium mesh reconstructions (p = 0.03). No significant difference was seen between the 2 groups in the number of patients with postoperative wound infections. Calcium phosphate cement provides a viable alternative biomaterial for calvarial reconstruction of retrosigmoid craniectomy defects in patients who have an MVD. The application of this material provides a biocompatible barrier that reduces the incidence of postoperative CSF leaks.

  18. [Microvascular decompression for hemifacial spasm. Ten years of experience].

    PubMed

    Revuelta-Gutiérrez, Rogelio; Vales-Hidalgo, Lourdes Olivia; Arvizu-Saldaña, Emiliano; Hinojosa-González, Ramón; Reyes-Moreno, Ignacio

    2003-01-01

    Hemifacial spasm characterized by involuntary paroxistic contractions of the face is more frequent on left side and in females. Evolution is progressive and in a few cases may disappear. Management includes medical treatment, botulinum toxin, and microvascular decompression of the nerve. We present the results of 116 microvascular decompressions performed in 88 patients over 10 years. All patients had previous medical treatment. All patients were operated on with microsurgical technique by asterional craniotomy. Vascular compression was present in all cases with one exception. Follow-up was from 1 month to 133 months. Were achieved excellent results in 70.45% of cases after first operation, good results in 9.09%, and poor results in 20.45% of patients. Long-term results were excellent in 81.82%, good in 6.82%, and poor in 11.36% of patients. Hypoacusia and transitory facial palsy were the main complications. Hemifacial spasm is a painless but disabling entity. Medical treatment is effective in a limited fashion. Injection of botulinum toxin has good response but benefit is transitory. Microvascular decompression is treatment of choice because it is minimally invasive, not destructive, requires minimum technical support, and yields best long-term results.

  19. Prospective Study of Neuroendoscopy versus Microscopy: 213 Cases of Microvascular Decompression for Trigeminal Neuralgia Performed by One Neurosurgeon.

    PubMed

    Xiang, Hui; Wu, Guangyong; Ouyang, Jia; Liu, Ruen

    2018-03-01

    To compare the efficacy and complications of microvascular decompression (MVD) by complete neuroendoscopy versus microscopy for 213 cases of trigeminal neuralgia (TN). Between January 2014 and January 2016, 213 patients with TN were randomly assigned to the neuroendoscopy (n = 105) or microscopy (n = 114) group for MVD via the suboccipital retrosigmoid approach. All procedures were performed by the same neurosurgeon. Follow-up was conducted by telephone interview. Statistical data were analyzed with the chi-square test, and a probability (P) value of ≤0.05 was considered statistically significant. Chi-square test was conducted using SAS 9.4 software (SAS Institute, Cary, North Carolina, USA). There were no statistical differences between the 2 groups in pain-free condition immediately post procedure, pain-free condition 1 year post procedure, hearing loss, facial hypoesthesia, transient ataxia, aseptic meningitis, intracranial infections, and herpetic lesions of the lips. There were no instances of death, facial paralysis, cerebral hemorrhage, or cerebrospinal fluid leakage in either group. There were no significant differences in the cure rates or incidences of surgical complications between neuroendoscopic and microscopic MVD. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Teflon Might Be a Factor Accounting for a Failed Microvascular Decompression in Hemifacial Spasm: A Technical Note.

    PubMed

    Dou, Ning-Ning; Zhong, Jun; Liu, Ming-Xing; Xia, Lei; Sun, Hui; Li, Bin; Li, Shi-Ting

    2016-01-01

    Although Teflon is widely adopted for microvascular decompression (MVD) surgery, it has never been addressed for failure analysis. This study analyzed the reasons for failed MVDs with emphasis on the Teflon sponge. Among the 685 hemifacial spasm cases between 2010 and 2014, 31 were reoperated on within a week because of unsatisfactory outcome, which was focused on in this study. Intraoperative findings regarding Teflon inserts of these repeat MVDs were reviewed. Among the 38 without satisfactory outcomes, 31 underwent repeat MVDs, and they were all spasm free afterwards. Eventually, the final cure rate was 99.2%. It was found in the repeat MVDs that the failure was attributable to the Teflon insert in most of the cases (74.2%) directly or indirectly. It was caused by improper placement (47.8%), inappropriate size (34.8%) and unsuitable shape (17.4%) of the Teflon sponge. Although it is not difficult for an experienced neurosurgeon to discover a neurovascular conflict during the MVD process, the size, shape and location of the Teflon sponge should not be ignored. Basically, the Teflon insert is used to keep the offending artery away from the facial nerve root rather than to isolate it. Therefore, the ideal Teflon sponge should be just small enough to produce a neurovascular separation. © 2016 S. Karger AG, Basel.

  1. Prospective comparison of long-term pain relief rates after first-time microvascular decompression and stereotactic radiosurgery for trigeminal neuralgia.

    PubMed

    Wang, Doris D; Raygor, Kunal P; Cage, Tene A; Ward, Mariann M; Westcott, Sarah; Barbaro, Nicholas M; Chang, Edward F

    2018-01-01

    OBJECTIVE Common surgical treatments for trigeminal neuralgia (TN) include microvascular decompression (MVD), stereotactic radiosurgery (SRS), and radiofrequency ablation (RFA). Although the efficacy of each procedure has been described, few studies have directly compared these treatment modalities on pain control for TN. Using a large prospective longitudinal database, the authors aimed to 1) directly compare long-term pain control rates for first-time surgical treatments for idiopathic TN, and 2) identify predictors of pain control. METHODS The authors reviewed a prospectively collected database for all patients who underwent treatment for TN between 1997 and 2014 at the University of California, San Francisco. Standardized collection of data on preoperative clinical characteristics, surgical procedure, and postoperative outcomes was performed. Data analyses were limited to those patients who received a first-time procedure for treatment of idiopathic TN with > 1 year of follow-up. RESULTS Of 764 surgical procedures performed at the University of California, San Francisco, for TN (364 SRS, 316 MVD, and 84 RFA), 340 patients underwent first-time treatment for idiopathic TN (164 MVD, 168 SRS, and 8 RFA) and had > 1 year of follow-up. The analysis was restricted to patients who underwent MVD or SRS. Patients who received MVD were younger than those who underwent SRS (median age 63 vs 72 years, respectively; p < 0.001). The mean follow-up was 59 ± 35 months for MVD and 59 ± 45 months for SRS. Approximately 38% of patients who underwent MVD or SRS had > 5 years of follow-up (60 of 164 and 64 of 168 patients, respectively). Immediate or short-term (< 3 months) postoperative pain-free rates (Barrow Neurological Institute Pain Intensity score of I) were 96% for MVD and 75% for SRS. Percentages of patients with Barrow Neurological Institute Pain Intensity score of I at 1, 5, and 10 years after MVD were 83%, 61%, and 44%, and the corresponding percentages after SRS were

  2. Analysis of wave III of brain stem auditory evoked potential waveforms during microvascular decompression of cranial nerve VII for hemifacial spasm.

    PubMed

    Thirumala, Parthasarathy D; Krishnaiah, Balaji; Crammond, Donald J; Habeych, Miguel E; Balzer, Jeffrey R

    2014-04-01

    Intraoperative monitoring of brain stem auditory evoked potential during microvascular decompression (MVD) prevent hearing loss (HL). Previous studies have shown that changes in wave III (wIII) are an early and sensitive sign of auditory nerve injury. To evaluate the changes of amplitude and latency of wIII of brain stem auditory evoked potential during MVD and its association with postoperative HL. Hearing loss was classified by American Academy of Otolaryngology - Head and Neck Surgery (AAO-HNS) criteria, based on changes in pure tone audiometry and speech discrimination score. Retrospective analysis of wIII in patients who underwent intraoperative monitoring with brain stem auditory evoked potential during MVD was performed. A univariate logistic regression analysis was performed on independent variables amplitude of wIII and latency of wIII at change max and On-Skin, or a final recording at the time of skin closure. A further analysis for the same variables was performed adjusting for the loss of wave. The latency of wIII was not found to be significantly different between groups I and II. The amplitude of wIII was significantly decreased in the group with HL. Regression analysis did not find any increased odds of HL with changes in the amplitude of wIII. Changes in wave III did not increase the odds of HL in patients who underwent brain stem auditory evoked potential s during MVD. This information might be valuable to evaluate the value of wIII as an alarm criterion during MVD to prevent HL.

  3. Delayed Unilateral Soft Palate Palsy without Vocal Cord Involvement after Microvascular Decompression for Hemifacial Spasm

    PubMed Central

    Park, Jae Han; Jo, Kyung Il

    2013-01-01

    Microvascular decompression is a very effective and relatively safe surgical modality in the treatment of hemifacial spasm. But rare debilitating complications have been reported such as cranial nerve dysfunctions. We have experienced a very rare case of unilateral soft palate palsy without the involvement of vocal cord following microvascular decompression. A 33-year-old female presented to our out-patient clinic with a history of left hemifacial spasm for 5 years. On postoperative 5th day, patient started to exhibit hoarsness with swallowing difficulty. Symptoms persisted despite rehabilitation. Various laboratory work up with magnetic resonance image showed no abnormal lesions. Two years after surgery patient showed complete recovery of unitaleral soft palate palsy. Various etiologies of unilateral soft palate palsy are reviewed as the treatment and prognosis differs greatly on the cause. Although rare, it is important to keep in mind that such complication could occur after microvascular decompression. PMID:24003372

  4. Effects of microvascular decompression on depression and anxiety in trigeminal neuralgia: A prospective cohort study focused on risk factors and prognosis.

    PubMed

    Cheng, Jian; Long, Jiang; Hui, Xuhui; Lei, Ding; Zhang, Heng

    2017-10-01

    Patients with trigeminal neuralgia (TN) often develop a terrible fear of triggering pain, which may lead to depression and anxiety, exerting a negative effect on their quality of life. This study aimed to investigate the prevalence and risk factors of depression and anxiety in TN patients, and further to investigate the effects of microvascular decompression (MVD) on these psychiatric disorders. A prospective cohort study was conducted, patients with TN who underwent MVD in our department between 2013 and 2015 were included. Visual analogue scale (VAS) score was used to measure the severity of pain. Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI) were used to evaluate depression and anxiety disorders before and 6-month after MVD. The clinical data of these patients were collected prospectively and statistically analyzed. A total of 128 study subjects comprising 70 women and 58 men with a mean age of 47.5±11.2years were included in this study. The mean VAS score was 7.7±1.5. Eighty-three patients (64.8%) had depression and 24 patients (18.8%) suffered anxiety. Multivariate logistic regression analysis revealed that female gender (OR=2.4, P=0.036), high pain intensity (OR=3.25, P=0.027) and ineffective medicine treatment (OR=1.89, P=0.041) were associated with depression, and female gender (OR=3.45, P=0.034) and high pain intensity (OR=2.88, P=0.022) were also associated with anxiety. There were significant improvements in depression and anxiety symptoms between pre- and postoperative responses. Depression and anxiety are prevalent in patients with idiopathic TN. Female gender, high pain intensity and ineffective medicine treatment are risk factors. MVD not only provides high pain-relief rate, but also leads to significant improvements in the depression and anxiety symptoms. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Pre-operative declining proportion of fractional anisotropy of trigeminal nerve is correlated with the outcome of micro-vascular decompression surgery.

    PubMed

    Chen, Fanfan; Chen, Lei; Li, Wei; Li, Ling; Xu, Xiangdong; Li, Weimin; Le, Wuhua; Xie, Wei; He, Hua; Li, Peng

    2016-07-16

    Type 2 trigeminal neuralgia (TN) is an intractable neuropathic pain syndrome compared with type 1 TN because of the difficulty of diagnosis as well as the unsatisfactory prognosis. Neurovascular compression (NVC) is considered the major pathology of TN. Routine magnetic resonance imaging (MRI) sequences are inadequate for revealing the effect of NVC which is related to the surgical decision and outcome. The decreasing of fractional anisotropy (FA), one of the MRI diffusion tensor imaging (DTI) metrics, is correlated with the demyelination of trigeminal nerve (TGN) that reveal the severity of NVC. A retrospective review of patients treated with micro-vascular decompression (MVD) surgery was undertaken. All the patients were diagnosed as type 2 TN. FA of TGN of both sides were measured. The FA declining proportion = ((the mean FA value of healthy lateral)-(the mean FA value of the symptomatic lateral))/(the mean FA value of healthy lateral). Declining proportion of FA value, discovery of surgery and outcome of MVD were recorded and analyzed. Logistic regression analysis and linear regression analysis were employed to analyze the risk factors of declining proportion of FA value and MVD outcome. Nineteen patients were assessed in our study. The average declining proportion of FA value for all patients was 0.25 ± 0.12. The average declining proportion of FA value of "success" and "failure" group was 0.32 ± 0.09 to 0.14 ± 0.10 (P = 0.002 < 0.05). The declining proportion of FA value of artery (including the artery plus vein situation) was 0.34 ± 0.06 in contrast to 0.15 ± 0.08 of vein (P = 0.000 < 0.05). MVD outcome was correlated with declining proportion of FA value (AUC = 0.900). Furthermore, declining proportion of FA value was higher in arterial compression situation. FA value quantitatively showed the alteration of TGN caused by NVC. It provided direct evidence about the effect of NVC which facilitated the diagnosis and surgical decision of type 2 TN

  6. Reduction in high-frequency hearing loss following technical modifications to microvascular decompression for hemifacial spasm.

    PubMed

    Thirumala, Parthasarathy; Frederickson, Andrew M; Balzer, Jeffrey; Crammond, Donald; Habeych, Miguel E; Chang, Yue-Fang; Sekula, Raymond F

    2015-10-01

    Microvascular decompression is a safe and effective procedure to treat hemifacial spasm, but the operation poses some risk to the patient's hearing. While severe sensorineural hearing loss across all frequencies occurs at a low rate in experienced hands, a recent study suggests that as many as one-half of patients who undergo this procedure may experience ipsilateral high-frequency hearing loss (HFHL), and as many as one-quarter may experience contralateral HFHL. While it has been suggested that drill-related noise may account for this finding, this study was designed to examine the effect of a number of techniques designed to protect the vestibulocochlear nerve from operative manipulation on the incidence of HFHL. Pure-tone audiometry was performed both preoperatively and postoperatively on 67 patients who underwent microvascular decompression for hemifacial spasm during the study period. A change of greater than 10 dB at either 4 kHz or 8 kHz was considered to be HFHL. Additionally, the authors analyzed intraoperative brainstem auditory evoked potentials from this patient cohort. The incidence of ipsilateral HFHL in this cohort was 7.4%, while the incidence of contralateral HFHL was 4.5%. One patient (1.5%; also included in the HFHL group) experienced an ipsilateral nonserviceable hearing loss. The reduced incidence of HFHL in this study suggests that technical modifications including performing the procedure without the use of fixed retraction may greatly reduce, but not eliminate, the occurrence of HFHL following microvascular decompression for hemifacial spasm.

  7. Microvascular decompression for the patient with painful tic convulsif after Bell palsy.

    PubMed

    Jiao, Wei; Zhong, Jun; Sun, Hui; Zhu, Jin; Zhou, Qiu-Meng; Yang, Xiao-Sheng; Li, Shi-Ting

    2013-05-01

    Painful tic convulsif is referred to as the concurrent trigeminal neuralgia and hemifacial spasm. However, painful tic convulsif after ipsilateral Bell palsy has never been reported before. We report a case of a 77-year-old woman with coexistent trigeminal neuralgia and hemifacial spasm who had experienced Bell palsy half a year ago. The patient underwent microvascular decompression. Intraoperatively, the vertebrobasilar artery was found to deviate to the symptomatic side and a severe adhesion was observed in the cerebellopontine angle. Meanwhile, an ectatic anterior inferior cerebellar artery and 2 branches of the superior cerebellar artery were identified to compress the caudal root entry zone (REZ) of the VII nerve and the rostroventral cisternal portion of the V nerve, respectively. Postoperatively, the symptoms of spasm ceased immediately and the pain disappeared within 3 months. In this article, the pathogenesis of the patient's illness was discussed and it was assumed that the adhesions developed from inflammatory reactions after Bell palsy and the anatomic features of the patient were the factors that generated the disorder. Microvascular decompression surgery is the suggested treatment of the disease, and the dissection should be started from the caudal cranial nerves while performing the operation.

  8. Hearing outcomes after loss of brainstem auditory evoked potentials during microvascular decompression.

    PubMed

    Thirumala, Parthasarathy D; Krishnaiah, Balaji; Habeych, Miguel E; Balzer, Jeffrey R; Crammond, Donald J

    2015-04-01

    The primary aim of this paper is to study the pre-operative characteristics, intra-operative changes and post-operative hearing outcomes in patients after complete loss of wave V of the brainstem auditory evoked potential. We retrospectively analyzed the brainstem auditory evoked potential data of 94 patients who underwent microvascular decompression for hemifacial spasm at our institute. Patients were divided into two groups - those with and those without loss of wave V. The differences between the two groups and outcomes were assessed using t-test and chi-squared tests. In our study 23 (24%) patients out of 94 had a complete loss of wave V, with 11 (48%) patients experiencing transient loss and 12 (52%) patients experiencing permanent loss. The incidence of hearing loss in patients with no loss of wave V was 5.7% and 26% in patients who did experience wave V loss. The incidence of hearing change in patients with no loss of wave V was 12.6% and 30.43% in patients who did experience wave V loss. Loss of wave V during the procedure or at the end of procedure significantly increases the odds of hearing loss. Hearing change is a significant under-reported clinical condition after microvascular decompression in patients who have loss of wave V. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Microvascular Decompression for Classical Trigeminal Neuralgia Caused by Venous Compression: Novel Anatomic Classifications and Surgical Strategy.

    PubMed

    Wu, Min; Fu, Xianming; Ji, Ying; Ding, Wanhai; Deng, Dali; Wang, Yehan; Jiang, Xiaofeng; Niu, Chaoshi

    2018-05-01

    Microvascular decompression of the trigeminal nerve is the most effective treatment for trigeminal neuralgia. However, when encountering classical trigeminal neuralgia caused by venous compression, the procedure becomes much more difficult, and failure or recurrence because of incomplete decompression may become frequent. This study aimed to investigate the anatomic variation of the culprit veins and discuss the surgical strategy for different types. We performed a retrospective analysis of 64 consecutive cases in whom veins were considered as responsible vessels alone or combined with other adjacent arteries. The study classified culprit veins according to operative anatomy and designed personalized approaches and decompression management according to different forms of compressive veins. Curative effects were assessed by the Barrow Neurological Institute (BNI) pain intensity score and BNI facial numbness score. The most commonly encountered veins were the superior petrosal venous complex (SPVC), which was artificially divided into 4 types according to both venous tributary distribution and empty point site. We synthetically considered these factors and selected an approach to expose the trigeminal root entry zone, including the suprafloccular transhorizontal fissure approach and infratentorial supracerebellar approach. The methods of decompression consist of interposing and transposing by using Teflon, and sometimes with the aid of medical adhesive. Nerve combing (NC) of the trigeminal root was conducted in situations of extremely difficult neurovascular compression, instead of sacrificing veins. Pain completely disappeared in 51 patients, and the excellent outcome rate was 79.7%. There were 13 patients with pain relief treated with reoperation. Postoperative complications included 10 cases of facial numbness, 1 case of intracranial infection, and 1 case of high-frequency hearing loss. The accuracy recognition of anatomic variation of the SPVC is crucial for the

  10. Vertebral artery pexy for microvascular decompression of the facial nerve in the treatment of hemifacial spasm.

    PubMed

    Ferreira, Manuel; Walcott, Brian P; Nahed, Brian V; Sekhar, Laligam N

    2011-06-01

    Hemifacial spasm (HFS) is caused by arterial or venous compression of cranial nerve VII at its root exit zone. Traditionally, microvascular decompression of the facial nerve has been an effective treatment for posterior inferior and anterior inferior cerebellar artery as well as venous compression. The traditional technique involves Teflon felt or another construct to cushion the offending vessel from the facial nerve, or cautery and division of the offending vein. However, using this technique for severe vertebral artery (VA) compression can be ineffective and fraught with complications. The authors report the use of a new technique of VA pexy to the petrous or clival dura mater in patients with HFS attributed to a severely ectatic and tortuous VA, and detail the results in a series of patients. Six patients with HFS due to VA compression underwent a retrosigmoid craniotomy, combined with a far-lateral approach in some patients. On identification of the site of VA compression, the vessel was mobilized adequately for the decompression. Great care was taken to avoid kinking the perforating vessels arising from the VA. Two 8-0 nylon sutures were passed through to the wall of the VA and then through the clival or petrous dura, and then tied to alleviate compression on cranial nerve VII. Patients were followed for at least 1 year postoperatively (mean 2.7 years, range 1-4 years). All 6 patients had complete resolution of their HFS. Facial function was tested postoperatively, and was stable when compared with the preoperative baseline. Two of the 3 patients with preoperative tinnitus had resolution of this symptom after the procedure. Postoperative imaging demonstrated VA decompression of the facial nerve and no evidence of stroke in all patients. One patient suffered from hearing loss, another developed a postoperative transient unilateral vocal cord paralysis, and a third patient developed a pseudomeningocele that resolved with the placement of a lumbar drain

  11. Microvascular Decompression for Treatment of Trigeminal Neuralgia in Patient with Facial Nerve Schwannoma.

    PubMed

    Marinelli, John P; Van Gompel, Jamie J; Link, Michael J; Carlson, Matthew L

    2018-05-01

    Secondary trigeminal neuralgia (TN) is uncommon. When a space-occupying lesion with mass effect is identified, the associated TN is often exclusively attributed to the tumor. This report illustrates the importance of considering coexistent actionable pathology when surgically treating secondary TN. A 51-year-old woman presented with abrupt-onset TN of the V2 and V3 nerve divisions with hypesthesia. She denied changes in hearing, balance, or facial nerve dysfunction. Magnetic resonance imaging revealed a 1.6-cm contrast-enhancing cerebellopontine angle tumor that effaced the trigeminal nerve, consistent with a vestibular schwannoma. In addition, a branch of the superior cerebellar artery abutted the cisternal segment of the trigeminal nerve on T2-weighted thin-slice magnetic resonance imaging. Intraoperative electrical stimulation of the tumor elicited a response from the facial nerve at low threshold over the entire accessible tumor surface, indicating that the tumor was a facial nerve schwannoma. Considering the patient's lack of facial nerve deficit and that the tumor exhibited no safe entry point for intracapsular debulking, tumor resection was not performed. Working between the tumor and tentorium, a branch of the superior cerebellar artery was identified and decompressed with a Teflon pad. At last follow-up, the patient exhibited resolution of her TN. Her hearing and facial nerve function remained intact. Despite obstruction from a medium-sized tumor, it is still possible to achieve microvascular decompression of the fifth cranial nerve. This emphasizes the importance of considering other actionable pathology during surgical management of presumed tumor-induced TN. Further, TN is relatively uncommon with medium-sized vestibular schwannomas and coexistent causes should be considered. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Hemilingual spasm: defining a new entity, its electrophysiological correlates and surgical treatment through microvascular decompression.

    PubMed

    Osburn, Leisha L; Møller, Aage R; Bhatt, Jay R; Cohen-Gadol, Aaron A

    2010-07-01

    We report on vascular compression syndrome of the 12th cranial nerve (hypoglossal), an occurrence not previously reported, and demonstrate, through corresponding objective electrophysiological evidence, that microvascular decompression of the hypoglossal nerve root can cure hemilingual spasm. A 52-year-old man had lower face muscle twitching and tongue spasms, which worsened with talking, chewing, or emotional stress. Carbamazepine offered only temporary relief, and relief from injections of botulinum toxin was insignificant. He was referred for surgical treatment. High-resolution magnetic resonance imaging of his posterior fossa contents revealed no obvious evidence of any compressive vessel along the facial nerve, but a compressive vessel along the hypoglossal nerve was apparent. The presence of preoperative tongue spasms encouraged interoperative monitoring of tongue motor responses. The facial nerve exit zone was explored, but microsurgical inspection of the seventh/eighth cranial nerve complex did not reveal any compressive vessel. However, at the anterolateral aspect of the medulla oblongata, the hypoglossal nerve was clearly compressed and distorted laterally by a large tortuous vertebral artery. When the artery was mobilized away from the nerve, the abnormal late electromyographic response to transcranial electrical stimulation disappeared; immediately after shredded Teflon was interpositioned between the artery and the nerve, the abnormal spontaneous tongue fasciculation also disappeared. The patient has remained spasm free 6 months after surgery. Hemilingual spasm may be caused by vascular contact/compression along cranial nerve XII at the lower brainstem and belong to the same family of cranial nerve hyperactivity disorders as hemifacial spasm.

  13. Value-based neurosurgery: measuring and reducing the cost of microvascular decompression surgery.

    PubMed

    McLaughlin, Nancy; Upadhyaya, Pooja; Buxey, Farzad; Martin, Neil A

    2014-09-01

    Care providers have put significant effort into optimizing patient safety and quality of care. Value, defined as meaningful outcomes achieved per dollar spent, is emerging as a promising framework to redesign health care. Scarce data exist regarding cost measurement and containment for episodes of neurosurgical care. The authors assessed how cost measurement and strategic containment could be used to optimize the value of delivered care after the implementation and maturation of quality improvement initiatives. A retrospective study of consecutive patients undergoing microvascular decompression was performed. Group 1 comprised patients treated prior to the implementation of quality improvement interventions, and Group 2 consisted of those treated after the implementation and maturation of quality improvement processes. A third group, Group 3, represented a contemporary group studied after the implementation of cost containment interventions targeting the three most expensive activities: pre-incision time in the operating room (OR) and total OR time, intraoperative neuromonitoring (IOM), and bed assignment (and overall length of stay [LOS]). The value of care was assessed for all three groups. Forty-four patients were included in the study. Average preparation time pre-incision decreased from 73 to 65 to 45 minutes in Groups 1, 2, and 3, respectively. The average total OR time and OR cost were 434 minutes and $8513 in Group 1; 348 minutes and $7592 in Group 2; and 407 minutes and $8333 in Group 3. The average cost for IOM, excluding electrode needles, was $1557, $1585, and $1263, respectively, in Groups 1, 2, and 3. Average total cost for bed assignment was $5747, $5198, and $4535, respectively, in Groups 1, 2, and 3. The average total LOS decreased from 3.16 days in Group 1 to 2.14 days in Group 3. Complete relief of or a significant decrease in preoperative symptomatology was achieved in 42 of the 44 patients, respectively. Overall, the average cost of a surgical

  14. MRI findings in patients with a history of failed prior microvascular decompression for hemifacial spasm: how to image and where to look.

    PubMed

    Hughes, M A; Branstetter, B F; Taylor, C T; Fakhran, S; Delfyett, W T; Frederickson, A M; Sekula, R F

    2015-04-01

    A minority of patients who undergo microvascular decompression for hemifacial spasm do not improve after the first operation. We sought to determine the most common locations of unaddressed neurovascular contact in patients with persistent or recurrent hemifacial spasm despite prior microvascular decompression. Eighteen patients with a history of a microvascular decompression presented with persistent hemifacial spasm. All patients underwent thin-section steady-state free precession MR imaging. Fourteen patients underwent repeat microvascular decompression at our institution. Images were evaluated for the following: the presence of persistent vascular compression of the facial nerve, type of culprit vessel (artery or vein), name of the culprit artery, segment of the nerve in contact with the vessel, and location of the point of contact relative to the existing surgical pledget. The imaging findings were compared with the operative findings. In 12 of the 18 patients (67%), persistent vascular compression was identified by imaging. In 11 of these 12 patients, the culprit vessel was an artery. Compression of the attached segment (along the ventral surface of the pons) was identified in most patients (58%, 7/12). The point of contact was proximal to the surgical pledget in most patients (83%, 10/12). The imaging interpretation was concordant with the surgical results regarding artery versus vein in 86% of cases and regarding the segment of the nerve contacted in 92%. In patients with persistent hemifacial spasm despite microvascular decompression, the unaddressed vascular compression is typically proximal to the previously placed pledget, usually along the attached segment of the nerve. Re-imaging with high-resolution T2-weighted MR imaging will usually identify the culprit vessel. © 2015 by American Journal of Neuroradiology.

  15. Microvascular decompression for hemifacial spasm secondary to vertebrobasilar dolichoectasia: surgical strategies, technical nuances and clinical outcomes.

    PubMed

    Zaidi, Hasan A; Awad, Al-Wala; Chowdhry, Shakeel A; Fusco, David; Nakaji, Peter; Spetzler, Robert F

    2015-01-01

    Hemifacial spasm (HFS) due to direct compression of the facial nerve by a dolichoectatic vertebrobasilar artery is rare. Vessels are often non-compliant and tethered by critical brainstem perforators. We set out to determine surgical strategies and outcomes for this challenging disease. All patients undergoing surgery for HFS secondary to vertebrobasilar dolichoectasia were reviewed. Hospital records, clinic notes and radiographic imaging were collected for outcome measures. Seventeen patients (eight males, nine females) were identified. Sixteen patients (94%) were treated with Teflon pledgets (DuPont, Wilmington, DE, USA) and one (6%) patient had a vascular sling placed around a severely diseased vertebral artery. All patients had significant reduction in symptoms and 82% of patients had complete resolution of symptoms (average follow-up: 41.4 months). One patient suffered persistent facial nerve paresis and swallowing difficulty. Two other patients suffered a 1 point decrease in the House-Brackmann facial nerve grading scale. Four patients (23%) required re-operation (infection, cerebrospinal fluid leak, and two patients with delayed recurrence of HFS). Of the latter, one patient required repositioning of a Teflon pledget and another patient underwent a sling decompression. There were no perioperative strokes or death. Excellent relief of symptoms with acceptable preoperative morbidity can be achieved using Teflon pledgets alone in most cases. In recalcitrant cases, sling transposition can be used to further augment the decompression. Careful attention must be paid to prevent vascular kinking and preserve brainstem perforators. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Successful Treatment with Microvascular Decompression Surgery of a Patient with Hemiparesis Caused by Vertebral Artery Compression of the Medulla Oblongata: Case Report and Review of the Literature.

    PubMed

    Ren, Jibin; Sun, Hongtao; Diao, Yunfeng; Niu, Xuegang; Wang, Hang; Wei, Zhengjun; Yuan, Fei

    2017-12-01

    There are few reports on hemiparesis caused by vascular medullary compression, which can occur because of dolichoectasia of the vertebrobasilar arterial system. In this article, we report a case of vertebral artery compression of the medulla oblongata in a 67-year-old woman. The patient was hypertensive, and she developed hemiparesis and intermittent spasms over 5 years. These spasms had worsened during the last year. Cranial nerve magnetic resonance imaging showed compression of the medulla oblongata by the left vertebral artery. A motor evoked potential (MEP) examination showed abnormal conduction of MEPs of bilateral toe abductors. The patient underwent microvascular decompression surgery under general anesthesia through a retrosigmoid keyhole approach. This operation led to relief of vascular compression and symptomatic improvement. Our case suggests that detailed history, imaging studies, and electrophysiologic studies help lead to a correct and early diagnosis of hemiparesis caused by vascular compression of the rostral ventrolateral medulla. Microvascular decompression surgery improves patient symptoms, and intraoperative electrophysiologic monitoring helps to avoid injury to important adjacent nerves. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Customer Service at MVD Field Offices.

    DOT National Transportation Integrated Search

    2008-06-01

    Through the Arizona Transportation Research Center, the Arizona Department of Transportation requested that research be performed to determine how Motor Vehicle Division (MVD) office customer service could be improved and wait times could be reduced....

  18. Sumatriptan improves postoperative quality of recovery and reduces postcraniotomy headache after cranial nerve decompression

    PubMed Central

    Venkatraghavan, L.; Li, L.; Bailey, T.; Manninen, P. H.; Tymianski, M.

    2016-01-01

    Background Microvascular decompression (MVD) is a surgical treatment for cranial nerve disorders via a small craniotomy. The postoperative pain of this procedure can be classified as surgical site somatic pain and postcraniotomy headache similar in nature to a migraine, including its association with photophobia, nausea, and vomiting. This headache can be difficult to treat and can impact on postoperative recovery. Sumatriptan is used to treat migraine-like headaches in various settings. This single-centre randomized controlled trial investigated whether postoperative administration of sumatriptan after MVD surgery impacts the quality of postoperative recovery. Methods Fifty patients who complained of postoperative headache after MVD were randomized to receive an s.c. injection of sumatriptan (6 mg) or saline. The primary outcome was quality of recovery as measured by the Quality of Recovery-40 (QoR-40) score at 24 h. Results The QoR-40 scores were significantly higher in the sumatriptan group (median 184; interquartile range 169–196) than in the placebo group (133; 119–155; P<0.01), suggesting higher quality of recovery. The sumatriptan group also had significantly lower headache scores at 4, 12, and 24 h. There were no significant differences in other secondary outcomes. Conclusions Use of sumatriptan improved the quality of recovery as measured by the QoR-40 and reduction of headache at 24 h after surgery. Sumatriptan is a useful alternative treatment for postcraniotomy headache. The mechanism remains unknown but could be related to reduction in headache, mood modulation, or both, mediated by a serotonin effect. Clinical trial registration NCT01632657. PMID:27317706

  19. Customer service at MVD field offices : final report 544.

    DOT National Transportation Integrated Search

    2008-06-01

    Through the Arizona Transportation Research Center, the Arizona Department of Transportation requested that research be performed to determine how Motor Vehicle Division (MVD) office customer service could be improved and wait times could be reduced....

  20. Orbital Decompression

    MedlinePlus

    ... A Complications of Sinusitis Epistaxis (Nosebleeds) Allergic Rhinitis (Hay Fever) Headaches and Sinus Disease Disorders of Smell & ... DCR) Disclosure Statement Printer Friendly Orbital Decompression John Lee, MD INTRODUCTION Orbital decompression is a surgical procedure ...

  1. Effect of microvascular distribution and its density on interstitial fluid pressure in solid tumors: A computational model.

    PubMed

    Mohammadi, M; Chen, P

    2015-09-01

    Solid tumors with different microvascular densities (MVD) have been shown to have different outcomes in clinical studies. Other studies have demonstrated the significant correlation between high MVD, elevated interstitial fluid pressure (IFP) and metastasis in cancers. Elevated IFP in solid tumors prevents drug macromolecules reaching most cancerous cells. To overcome this barrier, antiangiogenesis drugs can reduce MVD within the tumor and lower IFP. A quantitative approach is essential to compute how much reduction in MVD is required for a specific tumor to reach a desired amount of IFP for drug delivery purposes. Here we provide a computational framework to investigate how IFP is affected by the tumor size, the MVD, and location of vessels within the tumor. A general physiologically relevant tumor type with a heterogenous vascular structure surrounded by normal tissue is utilized. Then the continuity equation, Darcy's law, and Starling's equation are applied in the continuum mechanics model, which can calculate IFP for different cases of solid tumors. High MVD causes IFP elevation in solid tumors, and IFP distribution correlates with microvascular distribution within tumor tissue. However, for tumors with constant MVD but different microvascular structures, the average values of IFP were found to be the same. Moreover, for a constant MVD and vascular distribution, an increase in tumor size leads to increased IFP. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Further Assessment of MVD Effects in SLD Applications

    NASA Technical Reports Server (NTRS)

    Tsao, Jen-Ching; Anderson, David N.

    2006-01-01

    The study reported here is part of an effort to develop scaling methods for super cooled large droplet (SLD) conditions. Previously reported results showed that SLD main ice shapes can be simulated quite successfully by appendix C conditions using scaling methods developed for appendix C. However, when the velocity was higher than 100 kt, the feather size and density for SLD tests at MVDs well above 100 m was not well represented by the scaled appendix C conditions. This paper reports additional results of a study of the feather region with the objective of identifying differences between SLD and appendix C feathers. Both the feather appearance and the angle at which feathers grow from the airfoil surface were recorded over a range of MVD from 20 to 190 m for airspeeds of 100 and 200 kt and stagnation freezing fractions of 0.3 to 1.0. Tests were performed in the NASA Glenn Icing Research Tunnel (IRT) using a 91-cm-chord NACA0012 airfoil model mounted at 0 degrees AOA. Photographs are presented to illustrate details of feather appearance. Appearance was noticeably affected by the stagnation freezing fraction of the test, but not by velocity or MVD. The angle of feather growth relative to the chord line decreased with increasing stagnation freezing fraction. For a velocity of 100 kt, no significant effect of MVD on feather angle was apparent, but at 200 kt, feather angle tended to increase with MVD for glaze conditions, but not rime. This finding is based on limited data, and its significance with respect to icing physics has not been determined.

  3. Optic Nerve Decompression

    MedlinePlus

    ... Nerve Decompression Dacryocystorhinostomy (DCR) Disclosure Statement Printer Friendly Optic Nerve Decompression John Lee, MD Introduction Optic nerve decompression is a surgical procedure aimed at ...

  4. The readout chain for the bar PANDA MVD strip detector

    NASA Astrophysics Data System (ADS)

    Schnell, R.; Brinkmann, K.-Th.; Di Pietro, V.; Kleines, H.; Goerres, A.; Riccardi, A.; Rivetti, A.; Rolo, M. D.; Sohlbach, H.; Zaunick, H.-G.

    2015-02-01

    The bar PANDA (antiProton ANnihilation at DArmstadt) experiment will study the strong interaction in annihilation reactions between an antiproton beam and a stationary gas jet target. The detector will comprise different sub-detectors for tracking, particle identification and calorimetry. The Micro-Vertex Detector (MVD) as the innermost part of the tracking system will allow precise tracking and detection of secondary vertices. For the readout of the double-sided silicon strip sensors a custom-made ASIC is being developed, employing the Time-over-Threshold (ToT) technique for digitization and utilize time-to-digital converters (TDC) to provide a high-precision time stamp of the hit. A custom-made Module Data Concentrator ASIC (MDC) will multiplex the data of all front-ends of one sensor towards the CERN-developed GBT chip set (GigaBit Transceiver). The MicroTCA-based MVD Multiplexer Board (MMB) at the off-detector site will receive and concentrate the data from the GBT links and transfer it to FPGA-based compute nodes for global event building.

  5. [Microvascular descompression for trigeminal neuralgia: prognostic [corrected] factors].

    PubMed

    Alberione, F; Arena, A; Matera, R

    2008-06-01

    We describe our experience of the MVD in the typical trigeminal neuralgia and identify the prognostic factors. A retrospective studio of 89 cases between 1995-2005 was used. The prognostic significant data evaluated were demographics data; duration of neuralgia; the affected divisions involved; surgical findings; used material for the decompression. The data analysis was made with the chi(2) test. We have found an excellent outcome in 77% one year later. The age and the antecedent of hypertension disease were not statistically significant. A poor outcome was observed for: female sex, neuralgia lasting longer than two years, the three divisions involved, venous compression and the muscle used as surgical material. The MVD is an effective and reliable technique. The use of muscle is not recommended. When the three trigeminal divisions are involved we should choose another technique.

  6. Coronary microvascular rarefaction and myocardial fibrosis in heart failure with preserved ejection fraction.

    PubMed

    Mohammed, Selma F; Hussain, Saad; Mirzoyev, Sultan A; Edwards, William D; Maleszewski, Joseph J; Redfield, Margaret M

    2015-02-10

    Characterization of myocardial structural changes in heart failure with preserved ejection fraction (HFpEF) has been hindered by the limited availability of human cardiac tissue. Cardiac hypertrophy, coronary artery disease (CAD), coronary microvascular rarefaction, and myocardial fibrosis may contribute to HFpEF pathophysiology. We identified HFpEF patients (n=124) and age-appropriate control subjects (noncardiac death, no heart failure diagnosis; n=104) who underwent autopsy. Heart weight and CAD severity were obtained from the autopsy reports. With the use of whole-field digital microscopy and automated analysis algorithms in full-thickness left ventricular sections, microvascular density (MVD), myocardial fibrosis, and their relationship were quantified. Subjects with HFpEF had heavier hearts (median, 538 g; 169% of age-, sex-, and body size-expected heart weight versus 335 g; 112% in controls), more severe CAD (65% with ≥1 vessel with >50% diameter stenosis in HFpEF versus 13% in controls), more left ventricular fibrosis (median % area fibrosis, 9.6 versus 7.1) and lower MVD (median 961 versus 1316 vessels/mm(2)) than control (P<0.0001 for all). Myocardial fibrosis increased with decreasing MVD in controls (r=-0.28, P=0.004) and HFpEF (r=-0.26, P=0.004). Adjusting for MVD attenuated the group differences in fibrosis. Heart weight, fibrosis, and MVD were similar in HFpEF patients with CAD versus without CAD. In this study, patients with HFpEF had more cardiac hypertrophy, epicardial CAD, coronary microvascular rarefaction, and myocardial fibrosis than controls. Each of these findings may contribute to the left ventricular diastolic dysfunction and cardiac reserve function impairment characteristic of HFpEF. © 2014 American Heart Association, Inc.

  7. Additional Study of Water Droplet Median Volume Diameter (MVD) Effects on Ice Shapes

    NASA Technical Reports Server (NTRS)

    Tsao, Jen-Ching; Anderson, David N.

    2005-01-01

    This paper reports the result of an experimental study in the NASA Glenn Icing Research Tunnel (IRT) to evaluate how well the MVD-independent effect identified previously might apply to SLD conditions in rime icing situations. Models were NACA 0012 wing sections with chords of 53.3 and 91.4 cm. Tests were conducted with a nominal airspeed of 77 m/s (150 kt) and a number of MVD's ranging from 15 to 100 m with LWC of 0.5 to 1 g/cu m. In the present study, ice shapes recorded from past studies and recent results at SLD and Appendix-C conditions are reviewed to show that droplet diameter is not important to rime ice shape for MVD of 30 microns or larger, but for less than 30 m drop sizes a rime ice shape transition from convex to wedge to spearhead type ice shape is observed.

  8. Decompression Mechanisms and Decompression Schedule Calculations.

    DTIC Science & Technology

    1984-01-20

    phisiology - The effects of altitude. Handbook of Physiology, Section 3: Respiration, Vol. II. W.O. Fenn and H. Rahn eds. Wash, D.C.; Am. Physiol. Soc. 1 4...decompression studies from other laboratories. METHODS Ten experienced and physically qualified divers ( ages 22-42) were compressed at a rate of 60...STATISTICS* --- ---------------------------------------------------------- EXPERIMENT N AGE (yr) HEIGHT (cm) WEIGHT (Kg) BODY FAT

  9. First results of the front-end ASIC for the strip detector of the PANDA MVD

    NASA Astrophysics Data System (ADS)

    Quagli, T.; Brinkmann, K.-T.; Calvo, D.; Di Pietro, V.; Lai, A.; Riccardi, A.; Ritman, J.; Rivetti, A.; Rolo, M. D.; Stockmanns, T.; Wheadon, R.; Zambanini, A.

    2017-03-01

    PANDA is a key experiment of the future FAIR facility and the Micro Vertex Detector (MVD) is the innermost part of its tracking system. PASTA (PAnda STrip ASIC) is the readout chip for the strip part of the MVD. The chip is designed to provide high resolution timestamp and charge information with the Time over Threshold (ToT) technique. Its architecture is based on Time to Digital Converters with analog interpolators, with a time bin width of 50 ps. The chip implements Single Event Upset (SEU) protection techniques for its digital parts. A first full-size prototype with 64 channels was produced in a commercial 110 nm CMOS technology and the first characterizations of the prototype were performed.

  10. [Evaluation of three-dimensional tumor microvascular architecture phenotype heterogeneity in non-small cell carcinoma and its significance].

    PubMed

    Zhou, Hui; Liu, Jinkang; Chen, Shengxi; Xiong, Zeng; Zhou, Jianhua; Tong, Shiyu; Chen, Hao; Zhou, Moling

    2012-06-01

    To explore the degree, mechanism and clinical significance of three-dimensional tumor microvascular architecture phenotype heterogeneity (3D-TMAPH) in non-small cell carcinoma (NSCLC). Twenty-one samples of solitary pulmonary nodules were collected integrally. To establish two-dimensional tumor microvascular architecture phenotype (2D-TMAP) and three-dimensional tumor microvascular architecture phenotype (3D-TMAP), five layers of each nodule were selected and embedded in paraffin. Test indices included the expressions of vascular endothelial growth factor (VEGF), proliferating cell nuclear antigen (PCNA), EphB4, ephfinB2 and microvascular density marked by anti-CD34 (CD34-MVD). The degrees of 3D-TMAPH were evaluated by the coefficient of variation and extend of heterogeneity. Spearman rank correlation analysis was used to investigate the relationships between 2D-TMAP, 3D-TMAP and clinicopathological features. 3D-TMAPH showed that 2D-TMAP heterogeneity was expressed in the tissues of NSCLC. The heterogeneities in the malignant nodules were significantly higher than those in the active inflammatory nodules and tubercular nodules. In addition, different degrees of heterogeneity of CD34-MVD and PCNA were found in NSCLC tissues. The coefficients of variation of CD34- MVD and PCNA were positively related to the degree of differentiation (all P<0.05), but not related to the P-TNM stages, histological type or lymphatic metastasis (all P>0.05). The level of heterogeneity of various expression indexes (ephrinB2, EphB4, VEGF) in NSCLC tissues were inconsistent, but there were no significant differences in heterogeneity in NSCLC tissues with different histological types (P>0.05). 3D-TMAPH exists widely in the microenvironment during the genesis and development of NSCLC and has a significant impact on its biological complexity.

  11. Role of Inflammatory Reponse in Experimental Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Butler, B. D.; Little, T.

    1999-01-01

    Decompression to altitude can result in gas bubble formation both in tissues and in the systemic veins. The venous gas emboli (VGE) are often monitored during decompression exposures to assess risk for decompression sickness (DCS). Astronauts are at risk for DCS during extravehicular activities (EVA), where decompression occurs from the Space Shuttle or Space Station atmospheric pressure of 14.7 pounds per square inch (PSI) to that of the space suit pressure of 4.3 PSI. DCS symptoms include diffuse pain, especially around joints, inflammation and edema. Pathophysiological effects include interstitial inflammatory responses and recurring injury to the vascular endothelium. Such responses can result in vasoconstriction and associated hemodynamic changes.The granulocyte cell activation and chemotaxin release results in the formation of vasoactive and microvascular permeability altering mediators, especially from the lungs which are the principal target organ for the venous bubbles, and from activated cells (neutrophils, platelets, macrophages). Such mediators include free arachidonic acid and the byproducts of its metabolism via the cyclooxygenase and lipoxygenase pathways (see figure). The cyclooxygenase pathway results in formation of prostacyclin and other prostaglandins and thromboxanes that cause vasoconstriction, bronchoconstriction and platelet aggregation. Leukotrienes produced by the alternate pathway cause pulmonary and bronchial smooth muscle contraction and edema. Substances directly affecting vascular tone such as nitric oxide may also play a role in the respose to DCS. We are studying the role and consequent effects of the release inflammatory bioactive mediators as a result of DCS and VGE. More recent efforts are focused on identifying the effects of the body's circadian rhythm on these physiological consequences to decompression stress. al

  12. High-Sensitivity C-Reactive Protein Is a Predictor of Coronary Microvascular Dysfunction in Patients with Ischemic Heart Disease.

    PubMed

    Tong, David C; Whitbourn, Robert; MacIsaac, Andrew; Wilson, Andrew; Burns, Andrew; Palmer, Sonny; Layland, Jamie

    2017-01-01

    Inflammation and microvascular dysfunction (MVD) are independently associated with adverse cardiovascular outcomes in patients with ischemic heart disease. This study aimed to assess the relationship between inflammation, MVD, and myocardial injury. Coronary microvascular function was assessed in 74 patients undergoing percutaneous coronary intervention (PCI) using the index of microvascular resistance (IMR) by a pressure-temperature sensor-tipped wire. Serum high-sensitivity C-reactive protein (hsCRP) level was quantified by rate turbidimetry. Severe MVD was defined as IMR ≥ 30. Pearson correlation was computed to assess the relationships between hsCRP, troponin, and IMR of culprit vessel. Predictors of severe MVD were assessed by regression analysis. Acute coronary syndromes (ACSs) represented 49% of the total cohort. Study cohort was divided into low C-reactive protein (CRP) (hsCRP < 3 mg/L) and high CRP (hsCRP ≥ 3 mg/L) groups. There was higher representation of smokers (78 vs. 52%), diabetics (39 vs. 18%), and ACS (61 vs. 33%), as well as higher body mass index (29.4 ± 4.6 vs. 27.2 ± 4.1) in the high CRP group. Pre-PCI and post-PCI IMR were significantly elevated in the high CRP group compared to the low CRP group (pre-PCI IMR: 29.0 ± 13.9 vs. 17.4 ± 11.1, p  < 0.0001; post-PCI IMR: 23.0 ± 16.8 vs. 15.5 ± 8.4, p  = 0.02). Peak troponin levels were significantly raised in the high CRP group (9.96 ± 17.19 vs. 1.17 ± 3.00 μg/L, p  = 0.002). There was a strong positive correlation between hsCRP and pre-PCI IMR ( r  = 0.85, p  < 0.0001). Pre- and post-PCI IMR levels were correlated with peak troponin level ( r  = 0.45, p  < 0.0001; r  = 0.33, p  = 0.005, respectively). Predictors of severe MVD include male gender (OR 3.0), diabetes (OR 3.7), smoking history (OR 4.0), ACS presentation (OR 8.5), and hsCRP ≥ 3 mg/L (OR 5.6). hsCRP is a significant predictor of

  13. VEGF concentration from plasma-activated platelets rich correlates with microvascular density and grading in canine mast cell tumour spontaneous model

    PubMed Central

    Patruno, R; Arpaia, N; Gadaleta, CD; Passantino, L; Zizzo, N; Misino, A; Lucarelli, NM; Catino, A; Valerio, P; Ribatti, D; Ranieri, G

    2009-01-01

    Abstract Canine cutaneous mast cell tumour (CMCT) is a common cutaneous tumour in dog, with a higher incidence than in human. CMCT is classified in three subgroups, well and intermediately differentiated (G1 and G2), corresponding to a benign disease, and poorly differentiated (G3), corresponding to a malignant disease, which metastasize to lymph nodes, liver, spleen and bone marrow. In this study, we have evaluated serum (S), platelet-poor plasma (P-PP), plasma-activated platelet rich (P-APR) and cytosol vascular endothelial growth factor (VEGF) concentrations, microvascular density (MVD) and mast cell density (MCD) in a series of 86 CMCTs and we have correlated these parameters with each other, by means of ELISA detection of VEGF and immunohistochemistry. Results show that VEGF level from cytosol P-APR and MVD were significantly higher in G3 CMCTs as compared to G1 or G2 subgroups. Moreover, a significantly strong correlation among VEGF levels from P-PAR and cytosol, MVD and MCD was found in G3 subgroup. Because VEGF levels from P-APR well correlated with MVD and malignancy grade in CMCT, we suggest that VEGF might be secreted from MCs and it may be a suitable surrogate inter-species angiogenetic markers of tumour progression in CMCT. Finally, CMCT seems to be a useful model to study the role of MCs in tumour angiogenesis and inhibition of MCs degranulation or activation might be a new anti-angiogenic strategy worthy to further investigations. PMID:18429933

  14. Altitude-induced decompression sickness

    DOT National Transportation Integrated Search

    2010-01-01

    Decompression sickness (DCS) describes a condition characterized by a variety of symptoms resulting from exposure to low barometric pressures that cause inert gases (mainly nitrogen), normally dissolved in body fluids and tissues, to come out of phys...

  15. Expression of VEGF, VEGFR, EGFR, COX-2 and MVD in cervical carcinoma, in relation with the response to radio-chemotherapy.

    PubMed

    Nagy, Viorica Magdalena; Buiga, R; Brie, Ioana; Todor, N; Tudoran, Oana; Ordeanu, Claudia; Virág, Piroska; Tarta, Oana; Rus, Meda; Bălăcescu, O

    2011-01-01

    Despite the improvement in the treatment results due to modern irradiation techniques and to the association of chemo-radiotherapy, cervical cancer remains an unsolved problem of oncology both due to the increased rate of local failures and of the distant metastasis. Efforts to implement new therapeutic strategies in order to obtain better results in patients with cervical cancer appear justified. Neovascularization is an important step in the tumor progression and the therapeutic targeting of the tumor blood vessels appears to be a good strategy to follow in the anti-cancer treatment. Thus, even in an incipient phase of the clinical research process, the combination between the anti-angiogenic aimed therapies and the current radio-chemotherapy seems to represent a new, feasible and promising approach. The aim of the present study was to determine the prognostic and/or predictive value of some biological markers of tumor angiogenesis and of their implication in increasing the efficacy of current treatments for this cancer. So far, 54 women were included in a prospective trial: 44 having an advanced cervical carcinoma and 10 healthy women, as controls. A tumor biopsy and a blood sample were obtained from each patient before the start of therapy. The density of microvascularization was assessed using CD34 monoclonal antibody (hot spot technique), the expression of angiogenic factors VEGFR, EGFR and COX-2 were determined in tumor biopsies by specific immunohistochemistry techniques, using primary antibodies anti-EGFR, anti-VEGF and anti-COX-2 respectively. The quantitative polymerase chain reaction (Real Time PCR) was employed for assessing the expression level of the genes involved. Serum VEGF was determined by quantitative ELISA technique. Among the studied clinical and molecular factors, we found to be predictive for the type of response the following factors: tumor size at diagnosis (p=0.01), VEGFR2 expression (p=0.02) and a tendency to significance for patients

  16. [Orbital decompression in Grave's ophtalmopathy].

    PubMed

    Longueville, E

    2010-01-01

    Graves disease orbitopathy is a complex progressive inflammatory disease. Medical treatment remains in all cases the proposed treatment of choice. Surgical treatment by bone decompression can be considered as an emergency mainly in cases of optic neuropathy or ocular hypertension not being controlled medically or in post-traumatic exophthalmos stage. Emergency bone decompression eliminates compression or stretching of the optic nerve allowing visual recovery. The uncontrolled ocular hypertension will benefit from decompression. The normalization of intraocular pressure may be obtained by this surgery or if needed by the use of postoperative antiglaucoma drops or even filtration surgery. In all operated cases, the IOP was normalized with an average decrease of 7.71 mmHg and a cessation of eye drops in 3/7 cases. Regarding sequelae, our therapeutic strategy involves consecutively surgery of the orbit, extraocular muscles and eyelids. The orbital expansion gives excellent results on the cosmetic level and facilitates the implementation of subsequent actions.

  17. Effects of decompression on operator performance.

    DOT National Transportation Integrated Search

    1966-04-01

    The study was performed to provide more quantitative estimates of degradation of pilot performance following decompression and the extent to which a decompression with mask donning interrupts the task of piloting. The experiments utilized a Scow comp...

  18. A Start Toward Micronucleus-Based Decompression Models; Altitude Decompression

    NASA Technical Reports Server (NTRS)

    Van Liew, H. D.; Conkin, Johnny

    2007-01-01

    Do gaseous micronuclei trigger the formation of bubbles in decompression sickness (DCS)? Most previous instructions for DCS prevention have been oriented toward supersaturated gas in tissue. We are developing a mathematical model that is oriented toward the expected behavior of micronuclei. The issue is simplified in altitude decompressions because the aviator or astronaut is exposed only to decompression, whereas in diving there is a compression before the decompression. The model deals with four variables: duration of breathing of 100% oxygen before going to altitude (O2 prebreathing), altitude of the exposure, exposure duration, and rate of ascent. Assumptions: a) there is a population of micronuclei of various sizes having a range of characteristics, b) micronuclei are stable until they grow to a certain critical nucleation radius, c) it takes time for gas to diffuse in or out of micronuclei, and d) all other variables being equal, growth of micronuclei upon decompression is more rapid at high altitude because of the rarified gas in the micronuclei. To estimate parameters, we use a dataset of 4,756 men in altitude chambers exposed to various combinations of the model s variables. The model predicts occurrence of DCS symptoms quite well. It is notable that both the altitude chamber data and the model show little effect of O2 prebreathing until it lasts more than 60 minutes; this is in contrast to a conventional idea that the benefit of prebreathing is directly due to exponential washout of tissue nitrogen. The delay in response to O2 prebreathing can be interpreted as time required for outward diffusion of nitrogen; when the micronuclei become small enough, they are disabled, either by crushing or because they cannot expand to a critical nucleation size when the subject ascends to altitude.

  19. Cardiopulmonary Changes with Moderate Decompression in Rats

    NASA Technical Reports Server (NTRS)

    Robinson, R.; Little, T.; Doursout, M.-F.; Butler, B. D.; Chelly, J. E.

    1996-01-01

    Sprague-Dawley rats were compressed to 616 kPa for 120 min then decompressed at 38 kPa/min to assess the cardiovascular and pulmonary responses to moderate decompression stress. In one series of experiments the rats were chronically instrumented with Doppler ultrasonic probes for simultaneous measurement of blood pressure, cardiac output, heart rate, left and right ventricular wall thickening fraction, and venous bubble detection. Data were collected at base-line, throughout the compression/decompression protocol, and for 120 min post decompression. In a second series of experiments the pulmonary responses to the decompression protocol were evaluated in non-instrumented rats. Analyses included blood gases, pleural and bronchoalveolar lavage (BAL) protein and hemoglobin concentration, pulmonary edema, BAL and lung tissue phospholipids, lung compliance, and cell counts. Venous bubbles were directly observed in 90% of the rats where immediate post-decompression autopsy was performed and in 37% using implanted Doppler monitors. Cardiac output, stroke volume, and right ventricular wall thickening fractions were significantly decreased post decompression, whereas systemic vascular resistance was increased suggesting a decrease in venous return. BAL Hb and total protein levels were increased 0 and 60 min post decompression, pleural and plasma levels were unchanged. BAL white blood cells and neutrophil percentages were increased 0 and 60 min post decompression and pulmonary edema was detected. Venous bubbles produced with moderate decompression profiles give detectable cardiovascular and pulmonary responses in the rat.

  20. Spaceflight Decompression Sickness Contingency Plan

    NASA Technical Reports Server (NTRS)

    Dervay, Joseph P.

    2007-01-01

    A viewgraph presentation on the Decompression Sickness (DCS) Contingency Plan for manned spaceflight is shown. The topics include: 1) Approach; 2) DCS Contingency Plan Overview; 3) Extravehicular Activity (EVA) Cuff Classifications; 4) On-orbit Treatment Philosophy; 5) Long Form Malfunction Procedure (MAL); 6) Medical Checklist; 7) Flight Rules; 8) Crew Training; 9) Flight Surgeon / Biomedical Engineer (BME) Training; and 10) DCS Emergency Landing Site.

  1. European EVA decompression sickness risks

    NASA Astrophysics Data System (ADS)

    Vogt, Lorenz; Wenzel, Jürgen; Skoog, A. I.; Luck, S.; Svensson, Bengt

    For the first manned flight of Hermes there will be a capability of performing EVA. The European EVA Space Suit will be an anthropomorphic system with an internal pressure of 500 hPa of pure oxygen. The pressure reduction from the Hermes cabin pressure of 1013 hPa will induce a risk for Decompression Sickness (DCS) for the EVA crewmember if no adequate protective procedures are implemented. Specific decompression procedures have to be developed. From a critical review of the literature and by using knowledge gained from research conducted in the past in the fields of diving and aerospace medicine safe protective procedures are proposed for the European EVA scenario. An R factor of 1.2 and a tissue half-time ( t1/2) of 360 minutes in a single-tissue model have been identified as appropriate operational values. On the basis of an acceptable risk level of approximately 1%, oxygen prebreathing times are proposed for (a) direct pressure reduction from 1013 hPa to a suit pressure of 500 hPa, and (b) staged decompression using a 700 hPa intermediate stage in the spacecraft cabin. In addition, factors which influence individual susceptibility to DCS are identified. Recommendations are also given in the areas of crew selection and medical monitoring requirements together with therapeutic measures that can be implemented in the Hermes scenario. A method for demonstration of the validity of proposed risks and procedures is proposed.

  2. Graphics processing unit-assisted lossless decompression

    DOEpatents

    Loughry, Thomas A.

    2016-04-12

    Systems and methods for decompressing compressed data that has been compressed by way of a lossless compression algorithm are described herein. In a general embodiment, a graphics processing unit (GPU) is programmed to receive compressed data packets and decompress such packets in parallel. The compressed data packets are compressed representations of an image, and the lossless compression algorithm is a Rice compression algorithm.

  3. Xenon Blocks Neuronal Injury Associated with Decompression

    PubMed Central

    Blatteau, Jean-Eric; David, Hélène N.; Vallée, Nicolas; Meckler, Cedric; Demaistre, Sebastien; Lambrechts, Kate; Risso, Jean-Jacques; Abraini, Jacques H.

    2015-01-01

    Despite state-of-the-art hyperbaric oxygen (HBO) treatment, about 30% of patients suffering neurologic decompression sickness (DCS) exhibit incomplete recovery. Since the mechanisms of neurologic DCS involve ischemic processes which result in excitotoxicity, it is likely that HBO in combination with an anti-excitotoxic treatment would improve the outcome in patients being treated for DCS. Therefore, in the present study, we investigated the effect of the noble gas xenon in an ex vivo model of neurologic DCS. Xenon has been shown to provide neuroprotection in multiple models of acute ischemic insults. Fast decompression compared to slow decompression induced an increase in lactate dehydrogenase (LDH), a well-known marker of sub-lethal cell injury. Post-decompression administration of xenon blocked the increase in LDH release induced by fast decompression. These data suggest that xenon could be an efficient additional treatment to HBO for the treatment of neurologic DCS. PMID:26469983

  4. Xenon Blocks Neuronal Injury Associated with Decompression.

    PubMed

    Blatteau, Jean-Eric; David, Hélène N; Vallée, Nicolas; Meckler, Cedric; Demaistre, Sebastien; Lambrechts, Kate; Risso, Jean-Jacques; Abraini, Jacques H

    2015-10-15

    Despite state-of-the-art hyperbaric oxygen (HBO) treatment, about 30% of patients suffering neurologic decompression sickness (DCS) exhibit incomplete recovery. Since the mechanisms of neurologic DCS involve ischemic processes which result in excitotoxicity, it is likely that HBO in combination with an anti-excitotoxic treatment would improve the outcome in patients being treated for DCS. Therefore, in the present study, we investigated the effect of the noble gas xenon in an ex vivo model of neurologic DCS. Xenon has been shown to provide neuroprotection in multiple models of acute ischemic insults. Fast decompression compared to slow decompression induced an increase in lactate dehydrogenase (LDH), a well-known marker of sub-lethal cell injury. Post-decompression administration of xenon blocked the increase in LDH release induced by fast decompression. These data suggest that xenon could be an efficient additional treatment to HBO for the treatment of neurologic DCS.

  5. Oxygen equipment and rapid decompression studies.

    DOT National Transportation Integrated Search

    1979-03-01

    This is a collection of reports of evaluations of the protective capability of various oxygen systems at high altitude and during rapid decompression. Results of these studies were presented at scientific meetings and/or published in preprints or pro...

  6. Oxygen Equipment and Rapid Decompression Studies

    DTIC Science & Technology

    1979-03-01

    defined and discussed by Fritz Haber anti Hans Clamann (3) of the USAF School of Aviation Medicine.* These authors define two factors in a...for the pattern of airflow through the pene- tration; and (vi) maintenance of critical flow. The equation for rapid decompression as presented by Haber ...galley, controlling the pressure differential between the two compartments. Using the equation of Haber and Clamann (7), a decompression for the galley

  7. Orbital Decompression in Thyroid Eye Disease

    PubMed Central

    Fichter, N.; Guthoff, R. F.; Schittkowski, M. P.

    2012-01-01

    Though enlargement of the bony orbit by orbital decompression surgery has been known for about a century, surgical techniques vary all around the world mostly depending on the patient's clinical presentation but also on the institutional habits or the surgeon's skills. Ideally every surgical intervention should be tailored to the patient's specific needs. Therefore the aim of this paper is to review outcomes, hints, trends, and perspectives in orbital decompression surgery in thyroid eye disease regarding different surgical techniques. PMID:24558591

  8. Decompression models: review, relevance and validation capabilities.

    PubMed

    Hugon, J

    2014-01-01

    For more than a century, several types of mathematical models have been proposed to describe tissue desaturation mechanisms in order to limit decompression sickness. These models are statistically assessed by DCS cases, and, over time, have gradually included bubble formation biophysics. This paper proposes to review this evolution and discuss its limitations. This review is organized around the comparison of decompression model biophysical criteria and theoretical foundations. Then, the DCS-predictive capability was analyzed to assess whether it could be improved by combining different approaches. Most of the operational decompression models have a neo-Haldanian form. Nevertheless, bubble modeling has been gaining popularity, and the circulating bubble amount has become a major output. By merging both views, it seems possible to build a relevant global decompression model that intends to simulate bubble production while predicting DCS risks for all types of exposures and decompression profiles. A statistical approach combining both DCS and bubble detection databases has to be developed to calibrate a global decompression model. Doppler ultrasound and DCS data are essential: i. to make correlation and validation phases reliable; ii. to adjust biophysical criteria to fit at best the observed bubble kinetics; and iii. to build a relevant risk function.

  9. Use of psychological decompression in military operational environments.

    PubMed

    Hughes, Jamie G H Hacker; Earnshaw, N Mark; Greenberg, Neil; Eldridge, Rod; Fear, Nicola T; French, Claire; Deahl, Martin P; Wessely, Simon

    2008-06-01

    This article reviews the use of psychological decompression as applied to troops returning from active service in operational theaters. Definitions of the term are considered and a brief history is given. Current policies and practices are described and the question of mandatory decompression is considered. Finally, the evidence base for the efficacy of decompression is examined and some conclusions are drawn. This article highlights variations in the definition and practice of decompression and its use. Although there is, as yet, no evidence that decompression works, there is also no evidence to the contrary. Given the lack of knowledge as to the balance of risks and benefits of decompression and the absence of any definitive evidence that decompression is associated with improved mental health outcomes or that lack of decompression is associated with the reverse, it is argued that the use of decompression should remain a matter for discretion.

  10. [Mesh structure of two-dimensional tumor microvascular architecture phenotype heterogeneity in non-small cell lung cancer].

    PubMed

    Xiong, Zeng; Zhou, Hui; Liu, Jin-Kang; Hu, Cheng-Ping; Zhou, Mo-Ling; Xia, Yu; Zhou, Jian-Hua

    2009-11-01

    To investigate the structural characteristics and clinical significance of two-dimensional tumor microvascular architecture phenotype (2D-TMAP) in non-small cell lung cancer (NSCLC). Thirty surgical specimens of NSCLC were collected. The sections of the tumor tissues corresponding to the slice of CT perfusion imaging were selected to construct the 2D-TMAP expression. Spearman correlation analysis was used to examine the relation between the 2D-TMAP expression and the clinicopathological features of NSCLC. A heterogeneity was noted in the 2D-TMAP expression of NSCLC. The microvascular density (MVD) in the area surrounding the tumor was higher than that in the central area, but the difference was not statistically significant. The density of the microvessels without intact lumen was significantly greater in the surrounding area than in the central area (P=0.030). The total MVD was not correlated to tumor differentiation (r=0.042, P=0.831). The density of the microvessels without intact lumen in the surrounding area was positively correlated to degree of tumor differentiation and lymph node metastasis (r=0.528 and 0.533, P=0.041 and 0.028, respectively), and also to the expressions of vascular endothelial growth factor (VEGF), ephrinB2, EphB4, and proliferating cell nuclear antigen (PCNA) (r=0.504, 0.549, 0.549, and 0.370; P=0.005, 0.002, 0.002, and 0.048, respectively). The degree of tumor differentiation was positively correlated to PCNA and VEGF expression (r=0.604 and 0.370, P=0.001 and 0.048, respectively), but inversely to the integrity of microvascular basement membrane (r=-0.531, P=0.033). The 2D-TMAP suggests the overall state of the micro-environment for tumor growth. The 2D-TMAP of NSCLC regulates angiogenesis and tumor cell proliferation through a mesh-like structure, and better understanding of the characteristics and possible mechanism of 2D-TMAP expression can be of great clinical importance.

  11. Delayed facial nerve decompression for Bell's palsy.

    PubMed

    Kim, Sang Hoon; Jung, Junyang; Lee, Jong Ha; Byun, Jae Yong; Park, Moon Suh; Yeo, Seung Geun

    2016-07-01

    Incomplete recovery of facial motor function continues to be long-term sequelae in some patients with Bell's palsy. The purpose of this study was to investigate the efficacy of transmastoid facial nerve decompression after steroid and antiviral treatment in patients with late stage Bell's palsy. Twelve patients underwent surgical decompression for Bell's palsy 21-70 days after onset, whereas 22 patients were followed up after steroid and antiviral therapy without decompression. Surgical criteria included greater than 90 % degeneration on electroneuronography and no voluntary electromyography potentials. This study was a retrospective study of electrodiagnostic data and medical chart review between 2006 and 2013. Recovery from facial palsy was assessed using the House-Brackmann grading system. Final recovery rate did not differ significantly in the two groups; however, all patients in the decompression group recovered to at least House-Brackmann grade III at final follow-up. Although postoperative hearing threshold was increased in both groups, there was no significant between group difference in hearing threshold. Transmastoid decompression of the facial nerve in patients with severe late stage Bell's palsy at risk for a poor facial nerve outcome reduced severe complications of facial palsy with minimal morbidity.

  12. Computerized whole slide quantification shows increased microvascular density in pT2 prostate cancer as compared to normal prostate tissue.

    PubMed

    van Niekerk, Cornelis G; van der Laak, Jeroen A W M; Börger, M Elisa; Huisman, Henk-Jan; Witjes, J Alfred; Barentsz, Jelle O; Hulsbergen-van de Kaa, Christina A

    2009-01-01

    Contrast enhanced imaging enables powerful, non-invasive diagnostics, important for detection and staging of early prostate cancer. The uptake of contrast agent is increased in prostate cancer as compared to normal prostate tissue. To reveal the underlying physiological mechanisms, quantification of tissue components in pathology specimens may yield important information. Aim of this study was to investigate whether microvascularity is increased in prostate confined cancer (pT2). Radical prostatectomy specimens of 26 patients were selected for organ confined peripheral zone tumors which were restricted to one side of the prostate. Microvessels were visualized by immunohistochemistry against CD31. Specimens were scanned using a computer controlled microscope and scanning stage and vessels were recognized automatically. Pseudocolor mappings were produced showing number of vascular profiles (MVD), vascular area (MVA) and perimeter (MVP) in an overview of the entire prostate transection. MVD is a common measure for vascularity, whereas MVA represents the 3D vascular volume and MVP the perfused surface area. Mean, coefficient of variation and 75th percentile of these parameters were calculated automatically in manually indicated areas, consisting of the entire tumor area and the corresponding normal area in the contra lateral side of the prostate. The mappings clearly indicate areas of increased vascularity in prostate transections. In tumor tissue an increase was found compared to normal tissue of 81%, 49%, and 62% for mean MVD, mean MVA and mean MVP, respectively (P < 0.001 for all comparisons). In contrast, the heterogeneity in tumor vasculature was significantly decreased as compared to normal prostate (P < 0.001). Characteristics of microvasculature deviated significantly in pT2 prostate tumor as compared to normal tissue. Copyright 2008 Wiley-Liss, Inc.

  13. An evaluation of potential decompression hazards in small pressurized aircraft.

    DOT National Transportation Integrated Search

    1967-06-01

    Over 300 decompression tests were conducted to determine potential hazards of ejection or incapacitating or fatal head injuries in small volume pressurized aircraft in the event of sudden decompression following the loss of a window, emergency exit, ...

  14. Hypobaric decompression prebreathe requirements and breathing environment

    NASA Technical Reports Server (NTRS)

    Webb, James T.; Pilmanis, Andrew A.

    1993-01-01

    To reduce incidence of decompression sickness (DCS), prebreathing 100 percent oxygen to denitrogenate is required prior to hypobaric decompressions from a sea level pressure breathing environment to pressures lower than 350 mm Hg (20,000 ft; 6.8 psia). The tissue ratio (TR) of such exposures equals or exceeds 1.7; TR being the tissue nitrogen pressure prior to decompression divided by the total pressure after decompression (((0.781)(14.697))/6.758). Designing pressure suits capable of greater pressure differentials, lower TR's, and procedures which limit the potential for DCS occurrence would enhance operational efficiency. The current 10.2 psia stage decompression prior to extravehicular activity (EVA) from the Shuttle in the 100 percent oxygen, 4.3 psia suit, results in a TR of 1.65 and has proven to be relatively free of DCS. Our recent study of zero-prebreathe decompressions to 6.8 psia breathing 100 percent oxygen (TR = 1.66) also resulted in no DCS (N = 10). The level of severe, Spencer Grades 3 or 4, venous gas emboli (VGE) increased from 0 percent at 9.5 psia to 40 percent at 6.8 psia yielding a Probit curve of VGE risk for the 51 male subjects who participated in these recent studies. Earlier, analogous decompressions using a 50 percent oxygen, 50 percent nitrogen breathing mixture resulted in one case of DCS and significantly higher levels of severe VGE, e.g., at 7.8 psia, the mixed gas breathing environment resulted in a 56 percent incidence of severe VGE versus 10 percent with use of 100 percent oxygen. The report of this study recommended use of 100 percent oxygen during zero-prebreathe exposure to 6.8 psia if such a suit could be developed. For future, long-term missions, we suggest study of the effects of decompression over several days to a breathing environment of 150 mmHg O2 and approximately 52 mmHg He as a means of eliminating DCS and VGE hazards during subsequent excursions. Once physiologically adapted to a 4 psia vehicle, base, or space

  15. Evidence Report: Risk of Decompression Sickness (DCS)

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Norcross, Jason R.; Wessel, James H. III; Abercromby, Andrew F. J.; Klein, Jill S.; Dervay, Joseph P.; Gernhardt, Michael L.

    2013-01-01

    The Risk of Decompression Sickness (DCS) is identified by the NASA Human Research Program (HRP) as a recognized risk to human health and performance in space, as defined in the HRP Program Requirements Document (PRD). This Evidence Report provides a summary of the evidence that has been used to identify and characterize this risk. Given that tissue inert gas partial pressure is often greater than ambient pressure during phases of a mission, primarily during extravehicular activity (EVA), there is a possibility that decompression sickness may occur.

  16. Experimental diode laser-assisted microvascular anastomosis.

    PubMed

    Reali, U M; Gelli, R; Giannotti, V; Gori, F; Pratesi, R; Pini, R

    1993-05-01

    An experimental study to evaluate a diode-laser approach to microvascular end-to-end anastomoses is reported. Studies were carried out on the femoral arteries and veins of Wistar rats, and effective welding of vessel tissue was obtained at low laser power, by enhancing laser absorption with indocyanine green (Cardio-green) solution. The histologic and surgical effects of this laser technique were examined and compared with those of conventional microvascular sutured anastomoses.

  17. Spontaneous extracranial decompression of epidural hematoma.

    PubMed

    Neely, John C; Jones, Blaise V; Crone, Kerry R

    2008-03-01

    Epidural hematoma (EDH) is a common sequela of head trauma in children. An increasing number are managed nonsurgically, with close clinical and imaging observation. We report the case of a traumatic EDH that spontaneously decompressed into the subgaleal space, demonstrated on serial CT scans that showed resolution of the EDH and concurrent enlargement of the subgaleal hematoma.

  18. A Pottery Electric Kiln Using Decompression

    NASA Astrophysics Data System (ADS)

    Naoe, Nobuyuki; Yamada, Hirofumi; Nakayama, Tetsuo; Nakayama, Minoru; Minamide, Akiyuki; Takemata, Kazuya

    This paper presents a novel type electric kiln which fires the pottery using the decompression. The electric kiln is suitable for the environment and the energy saving as the pottery furnace. This paper described the baking principle and the baking characteristic of the novel type electric kiln.

  19. Pictorial essay: Role of ultrasound in failed carpal tunnel decompression.

    PubMed

    Botchu, Rajesh; Khan, Aman; Jeyapalan, Kanagaratnam

    2012-01-01

    USG has been used for the diagnosis of carpal tunnel syndrome. Scarring and incomplete decompression are the main causes for persistence or recurrence of symptoms. We performed a retrospective study to assess the role of ultrasound in failed carpal tunnel decompression. Of 422 USG studies of the wrist performed at our center over the last 5 years, 14 were for failed carpal tunnel decompression. Scarring was noted in three patients, incomplete decompression in two patients, synovitis in one patient, and an anomalous muscle belly in one patient. No abnormality was detected in seven patients. We present a pictorial review of USG findings in failed carpal tunnel decompression.

  20. Pictorial essay: Role of ultrasound in failed carpal tunnel decompression

    PubMed Central

    Botchu, Rajesh; Khan, Aman; Jeyapalan, Kanagaratnam

    2012-01-01

    USG has been used for the diagnosis of carpal tunnel syndrome. Scarring and incomplete decompression are the main causes for persistence or recurrence of symptoms. We performed a retrospective study to assess the role of ultrasound in failed carpal tunnel decompression. Of 422 USG studies of the wrist performed at our center over the last 5 years, 14 were for failed carpal tunnel decompression. Scarring was noted in three patients, incomplete decompression in two patients, synovitis in one patient, and an anomalous muscle belly in one patient. No abnormality was detected in seven patients. We present a pictorial review of USG findings in failed carpal tunnel decompression. PMID:22623813

  1. Microvascular pericytes in healthy and diseased kidneys

    PubMed Central

    Pan, Szu-Yu; Chang, Yu-Ting; Lin, Shuei-Liong

    2014-01-01

    Pericytes are interstitial mesenchymal cells found in many major organs. In the kidney, microvascular pericytes are defined anatomically as extensively branched, collagen-producing cells in close contact with endothelial cells. Although many molecular markers have been proposed, none of them can identify the pericytes with satisfactory specificity or sensitivity. The roles of microvascular pericytes in kidneys were poorly understood in the past. Recently, by using genetic lineage tracing to label collagen-producing cells or mesenchymal cells, the elusive characteristics of the pericytes have been illuminated. The purpose of this article is to review recent advances in the understanding of microvascular pericytes in the kidneys. In healthy kidney, the pericytes are found to take part in the maintenance of microvascular stability. Detachment of the pericytes from the microvasculature and loss of the close contact with endothelial cells have been observed during renal insult. Renal microvascular pericytes have been shown to be the major source of scar-forming myofibroblasts in fibrogenic kidney disease. Targeting the crosstalk between pericytes and neighboring endothelial cells or tubular epithelial cells may inhibit the pericyte–myofibroblast transition, prevent peritubular capillary rarefaction, and attenuate renal fibrosis. In addition, renal pericytes deserve attention for their potential to produce erythropoietin in healthy kidneys as pericytes stand in the front line, sensing the change of oxygenation and hemoglobin concentration. Further delineation of the mechanisms underlying the reduced erythropoietin production occurring during pericyte–myofibroblast transition may be promising for the development of new treatment strategies for anemia in chronic kidney disease. PMID:24465134

  2. Ambulation Increases Decompression Sickness in Altitude Exposure

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Pollock, N. W.; Natoli, M. J.; Wessel, J. H., III; Gernhardt, M. L.

    2014-01-01

    INTRODUCTION - Exercise accelerates inert gas elimination during oxygen breathing prior to decompression (prebreathe), but may also promote bubble formation and increase the risk of decompression sickness (DCS). The timing, pattern and intensity of exercise are likely critical to the net effect. The NASA Prebreathe Reduction Program (PRP) combined oxygen prebreathe and exercise preceding a 4.3 psi exposure in non-ambulatory subjects (a microgravity analog) to produce two protocols now used by astronauts preparing for extravehicular activity (CEVIS and ISLE). Additional work is required to investigate whether exercise normal to 1 G environments increases the risk of DCS over microgravity simulation. METHODS - The CEVIS protocol was replicated with one exception. Our subjects completed controlled ambulation (walking in place with fixed cadence and step height) during both preflight and at 4.3 psi instead of remaining non-ambulatory throughout. Decompression stress was graded with aural Doppler (Spencer 0-IV scale). Two-dimensional echocardiographic imaging was used to look for left heart gas emboli (the presence of which prompted test termination). Venous blood was collected at three points to correlate Doppler measures of decompression stress with microparticle (cell fragment) accumulation. Fisher Exact Tests compared test and control groups. Trial suspension would occur when DCS risk >15% or grade IV venous gas emboli (VGE) risk >20% (at 70% confidence). RESULTS - Eleven person-trials were completed (9 male, 2 female) when DCS prompted suspension. DCS was greater than in CEVIS trials (3/11 [27%] vs. 0/45 [0%], respectively, p=0.03). Statistical significance was not reached for peak grade IV VGE (2/11 [18%] vs. 3/45 [7%], p=0.149) or cumulative grade IV VGE observations per subject-trial (8/128 [6%] vs. 26/630 [4%], p=0.151). Microparticle data were collected for 5/11 trials (3 with DCS outcomes), with widely varying patterns that could not be resolved statistically

  3. Graft microvascular disease in solid organ transplantation.

    PubMed

    Jiang, Xinguo; Sung, Yon K; Tian, Wen; Qian, Jin; Semenza, Gregg L; Nicolls, Mark R

    2014-08-01

    Alloimmune inflammation damages the microvasculature of solid organ transplants during acute rejection. Although immunosuppressive drugs diminish the inflammatory response, they do not directly promote vascular repair. Repetitive microvascular injury with insufficient regeneration results in prolonged tissue hypoxia and fibrotic remodeling. While clinical studies show that a loss of the microvascular circulation precedes and may act as an initiating factor for the development of chronic rejection, preclinical studies demonstrate that improved microvascular perfusion during acute rejection delays and attenuates tissue fibrosis. Therefore, preservation of a functional microvasculature may represent an effective therapeutic strategy for preventing chronic rejection. Here, we review recent advances in our understanding of the role of the microvasculature in the long-term survival of transplanted solid organs. We also highlight microvessel-centered therapeutic strategies for prolonging the survival of solid organ transplants.

  4. Decompression scenarios in a new underground transportation system.

    PubMed

    Vernez, D

    2000-10-01

    The risks of a public exposure to a sudden decompression, until now, have been related to civil aviation and, at a lesser extent, to diving activities. However, engineers are currently planning the use of low pressure environments for underground transportation. This method has been proposed for the future Swissmetro, a high-speed underground train designed for inter-urban linking in Switzerland. The use of a low pressure environment in an underground public transportation system must be considered carefully regarding the decompression risks. Indeed, due to the enclosed environment, both decompression kinetics and safety measures may differ from aviation decompression cases. A theoretical study of decompression risks has been conducted at an early stage of the Swissmetro project. A three-compartment theoretical model, based on the physics of fluids, has been implemented with flow processing software (Ithink 5.0). Simulations have been conducted in order to analyze "decompression scenarios" for a wide range of parameters, relevant in the context of the Swissmetro main study. Simulation results cover a wide range from slow to explosive decompression, depending on the simulation parameters. Not surprisingly, the leaking orifice area has a tremendous impact on barotraumatic effects, while the tunnel pressure may significantly affect both hypoxic and barotraumatic effects. Calculations have also shown that reducing the free space around the vehicle may mitigate significantly an accidental decompression. Numeric simulations are relevant to assess decompression risks in the future Swissmetro system. The decompression model has proven to be useful in assisting both design choices and safety management.

  5. Identifying the Subtle Presentation of Decompression Sickness.

    PubMed

    Alea, Kenneth

    2015-12-01

    Decompression sickness is an inherent occupational hazard that has the possibility to leave its victims with significant long-lasting effects that can potentially impact an aircrew's flight status. The relative infrequency of this hazard within the military flying community along with the potentially subtle presentation of decompression sickness (DCS) has the potential to result in delayed diagnosis and treatment, leading to residual deficits that can impact a patient's daily life or even lead to death. The patient presented in this work was diagnosed with a Type II DCS 21 h after a cabin decompression at 35,000 ft (10,668 m). The patient had been asymptomatic with a completely normal physical/neurological exam following his flight. The following day, he presented with excessive fatigue and on re-evaluation was recommended for hyperbaric therapy, during which his symptoms completely resolved. He was re-evaluated 14 d later and cleared to resume flight duties without further incident. The manifestation of this patient's decompression sickness was subtle and followed an evaluation that failed to identify any focal findings. A high index of suspicion with strict follow-up contributed to the identification of DCS in this case, resulting in definitive treatment and resolution of the patient's symptoms. Determination of the need for hyperbaric therapy following oxygen supplementation and a thorough history and physical is imperative. If the diagnosis is in question, consider preemptive hyperbaric therapy as the benefits of treatment in DCS outweigh the risks of treatment. Finally, this work introduces the future potential of neuropsychological testing for both the diagnosis of DCS as well as assessing the effectiveness of hyperbaric therapy in Type II DCS.

  6. Space Flight Decompression Sickness Contingency Plan

    NASA Technical Reports Server (NTRS)

    Dervay, Joseph; Gernhardt, Michael L.; Ross, Charles E.; Hamilton, Douglas; Homick, Jerry L. (Technical Monitor)

    2000-01-01

    The purpose was to develop an enhanced plan to diagnose, treat, and manage decompression sickness (DCS) during extravehicular activity (EVA). This plan is merited by the high frequency of upcoming EVAs necessary to construct and maintain the International Space Station (ISS). The upcoming ISS era will demand a significant increase in EVA. The DCS Risk and Contingency Plan provided a new and improved approach to DCS reporting, treatment, management, and training.

  7. Greater Occipital Nerve Decompression for Occipital Neuralgia.

    PubMed

    Jose, Anson; Nagori, Shakil Ahmed; Chattopadhyay, Probodh K; Roychoudhury, Ajoy

    2018-05-14

    The aim of the study was to evaluate the effectiveness of greater occipital nerve decompression for the management of occipital neuralgia. Eleven patients of medical refractory occipital neuralgia were enrolled in the study. Local anaesthetic blocks were used for confirming diagnosis. All of them underwent surgical decompression of greater occipital nerve at the level of semispinalis capitis and trapezial tunnel. A pre and postoperative questionnaire was used to compare the severity of pain and number of pain episodes/month. Mean pain episodes reported by patients before surgery were 17.1 ± 5.63 episodes per month. This reduced to 4.1 ± 3.51 episodes per month (P < 0.0036) postsurgery. The mean intensity of pain also reduced from a preoperative 7.18 ± 1.33 to a postoperative of 1.73 ± 1.95 (P < 0.0033). Three patients reported complete elimination of pain after surgery while 6 patients reported significant relief of their symptoms. Only 2 patients failed to notice any significant improvement. The mean follow-up period was 12.45 ± 1.29 months. Surgical decompression of greater occipital nerve is a simple and viable treatment modality for the management of occipital neuralgia.

  8. Macrovascular Decompression of Facial Nerve With Anteromedial Transposition of a Dolichoectatic Vertebral Artery: 3-Dimensional Operative Video.

    PubMed

    Tabani, Halima; Yousef, Sonia; Burkhardt, Jan-Karl; Gandhi, Sirin; Benet, Arnau; Lawton, Michael T

    2018-05-21

    Most cranial nerve compression syndromes (ie, trigeminal neuralgia and hemifacial spasm) are caused by small arteries impinging on a nerve and are relieved by microvascular decompression. Rarely, cranial nerve compression syndromes can be caused by large artery impingement and can be relieved by macrovascular decompression. When present, this compression often occurs in association with degenerative atherosclerosis in the vertebral arteries (VA) and basilar artery. Conservative treatment is recommended for mild forms, but surgical transposition of the VA away from the root entry zone (REZ) can be considered. This video demonstrates macrovascular decompression of a dolichoectatic VA in a 74-yr-old female with refractory left hemifacial spasm. After obtaining IRB approval, patient consent was sought for the procedure. With the patient in three-quarter-prone position, a far-lateral craniotomy was performed. The dentate ligament was cut to free the VA, and the suprahypoglossal portion of the vagoaccessory triangle was widened. VA compressed the REZ of the facial nerve, but was mobilized anteromedially off the REZ. A muslin sling was wrapped around the VA and its tail brought down to the clival dura, which was punctured with a 19-gauge needle and enlarged with a dissector. The sling was pulled anteromedially to this puncture site and secured to the dura with an aneurysm clip, relieving the REZ of all compression. The patient tolerated the procedure with mild, transient hoarseness and her hemifacial spasm resolved completely. This case demonstrates the macrovascular decompression technique with anteromedial transposition of the vertebrobasilar artery, which can also be used for trigeminal neuralgia.

  9. Coronary microvascular dysfunction in diabetes mellitus

    PubMed Central

    Selthofer-Relatic, Kristina; Drenjancevic, Ines; Bacun, Tatjana; Bosnjak, Ivica; Kibel, Dijana; Gros, Mario

    2017-01-01

    The significance, mechanisms and consequences of coronary microvascular dysfunction associated with diabetes mellitus are topics into which we have insufficient insight at this time. It is widely recognized that endothelial dysfunction that is caused by diabetes in various vascular beds contributes to a wide range of complications and exerts unfavorable effects on microcirculatory regulation. The coronary microcirculation is precisely regulated through a number of interconnected physiological processes with the purpose of matching local blood flow to myocardial metabolic demands. Dysregulation of this network might contribute to varying degrees of pathological consequences. This review discusses the most important findings regarding coronary microvascular dysfunction in diabetes from pre-clinical and clinical perspectives. PMID:28643578

  10. Comparative incidences of decompression illness in repetitive, staged, mixed-gas decompression diving: is 'dive fitness' an influencing factor?

    PubMed

    Sayer, Martin Dj; Akroyd, Jim; Williams, Guy D

    2008-06-01

    Wreck diving at Bikini Atoll consists of a relatively standard series of decompression dives with maximum depths in the region of 45-55 metres' sea water (msw). In a typical week of diving at Bikini, divers can perform up to 12 decompression dives to these depths over seven days; on five of those days, divers can perform two decompression dives per day. All the dives employ multi-level, staged decompression schedules using air and surface-supplied nitrox containing 80% oxygen. Bikini is serviced by a single diving operator and so a relatively precise record exists both of the actual number of dives undertaken and of the decompression illness incidents both for customer divers and the dive guides. The dive guides follow exactly the dive profiles and decompression schedules of the customers. Each dive guide will perform nearly 400 decompression dives a year, with maximum depths mostly around 50 msw, compared with an average of 10 (maximum of 12) undertaken typically by each customer diver in a week. The incidence of decompression illness for the customer population (presumed in the absence of medical records) is over ten times higher than that for the dive guides. The physiological reasons for such a marked difference are discussed in terms of customer demographics and dive-guide acclimatization to repetitive decompression stress. The rates of decompression illness for a range of diving populations are reviewed.

  11. Surgical orbital decompression for thyroid eye disease.

    PubMed

    Boboridis, Kostas G; Bunce, Catey

    2011-12-07

    Orbital decompression is an established procedure for the management of exophthalmos and visual rehabilitation from optic neuropathy in cases of thyroid eye disease. Numerous procedures for removal of orbital bony wall, fat or a combination of these for a variety of indications in different stages of the disease have been well reported in the medical literature. However, the relative effectiveness and safety of these procedures in relation to the various indications remains unclear. To review current published evidence for the effectiveness of surgical orbital decompression for disfiguring proptosis in adult thyroid eye disease and summa rise information on possible complications and the quality of life from the studies identified. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 10), MEDLINE (January 1950 to October 2011), EMBASE (January 1980 to October 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) and ClinicalTrials.gov (http://clinicaltrials.gov). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 6 October 2011. We searched oculoplastic textbooks, conference proceedings from the European and American Society of Ophthalmic Plastic and Reconstructive Surgery (ESOPRS, ASOPRS), European Ophthalmological Society (SOE), the Association for Research in Vision and Ophthalmology (ARVO) and American Academy of Ophthalmology (AAO) for the years 2000 to 2009 to identify relevant data. We attempted to contact researchers who are active in this field for information about further published or unpublished studies. We included randomised controlled trials (RCTs) with no restriction on date or language comparing two or more surgical methods for orbital decompression with removal of bony wall, orbital fat or a combination of both for disfiguring proptosis or comparison of surgical techniques

  12. Needle Decompression of Tension Pneumothorax with Colorimetric Capnography.

    PubMed

    Naik, Nimesh D; Hernandez, Matthew C; Anderson, Jeff R; Ross, Erika K; Zielinski, Martin D; Aho, Johnathon M

    2017-11-01

    The success of needle decompression for tension pneumothorax is variable, and there are no objective measures assessing effective decompression. Colorimetric capnography, which detects carbon dioxide present within the pleural space, may serve as a simple test to assess effective needle decompression. Three swine underwent traumatically induced tension pneumothorax (standard of care, n = 15; standard of care with needle capnography, n = 15). Needle thoracostomy was performed with an 8-cm angiocatheter. Similarly, decompression was performed with the addition of colorimetric capnography. Subjective operator assessment of decompression was recorded and compared with true decompression, using thoracoscopic visualization for both techniques. Areas under receiver operating curves were calculated and pairwise comparison was performed to assess statistical significance (P < .05). The detection of decompression by needle colorimetric capnography was found to be 100% accurate (15 of 15 attempts), when compared with thoracoscopic assessment (true decompression). Furthermore, it accurately detected the lack of tension pneumothorax, that is, the absence of any pathologic/space-occupying lesion, in 100% of cases (10 of 10 attempts). Standard of care needle decompression was detected by operators in 9 of 15 attempts (60%) and was detected in 3 of 10 attempts when tension pneumothorax was not present (30%). True decompression, under direct visualization with thoracoscopy, occurred 15 of 15 times (100%) with capnography, and 12 of 15 times (80%) without capnography. Areas under receiver operating curves were 0.65 for standard of care and 1.0 for needle capnography (P = .002). Needle decompression with colorimetric capnography provides a rapid, effective, and highly accurate method for eliminating operator bias for tension pneumothorax decompression. This may be useful for the treatment of this life-threatening condition. Copyright © 2017 American College of Chest Physicians

  13. Thromboprophylaxis in Head and Neck Microvascular Reconstruction.

    PubMed

    Abraham, Manoj; Badhey, Arvind; Hu, Shirley; Kadakia, Sameep; Rasamny, J K; Moscatello, Augustine; Ducic, Yadranko

    2018-06-01

    Head and neck patients undergoing microvascular reconstruction are at high risk for thromboembolism. While the prevention of thromboembolism has become an essential aspect of care, within the field of microsurgery, concern for anastomotic complications have hindered the creation of an accepted regimen. The aim of this review was to evaluate the risks and benefits of prophylactic agents for thromboprophylaxis. A literature search was conducted in MEDLINE, Cochrane Library, and PubMed/NCBI databases. Articles discussing thromboprophylaxis in otolaryngology, head and neck surgery, or microvascular reconstruction were considered in the review from the past 30 years. The majority of patients undergoing microvascular surgery have multiple risk factors for thrombus formation. Several consensus guidelines exist for the prophylaxis in patients who are critically ill, undergoing surgery, or with malignancy. Significant evidence supports the routine use of mechanical means, such as early mobilization and pneumatic compression along with subcutaneous heparin. Low-molecular-weight heparin is also frequently utilized, although results are largely divided. Data on aspirin remain equivocal. Studies on microvascular failure and flap loss have demonstrated little to no association with chemoprophylaxis. The evidence for postoperative thromboprophylaxis regimens in patients undergoing head and neck free tissue transfer is variable. Multiple studies have supported the use of unfractionated heparin or low-molecular-weight heparin. There appears to be an expert consensus for the combined use of mechanical prophylactic methods and chemical prophylaxis. Prospective randomized trials are required to validate the most effective combination of chemoprophylaxis agents.

  14. Redistribution of Decompression Stop Time from Shallow to Deep Stops Increases Incidence of Decompression Sickness in Air Decompression Dives

    DTIC Science & Technology

    2011-07-22

    year old active duty male diver surfaced from a 170/30 air dive at <corr>12:11<corr> on 24AUG06 using MK 20 FFM and following the A-2 “deep stops...effort, and this episode responded immediately to pressure. AGE is unlikely due to the experience of the diver, the MK 20 FFM characteristics, and...from a 170/30 air dive at <corr>12:11<corr> on 24AUG06 using MK 20 FFM and following the A-2 “deep stops” experimental decompression profile

  15. Spatial domain entertainment audio decompression/compression

    NASA Astrophysics Data System (ADS)

    Chan, Y. K.; Tam, Ka Him K.

    2014-02-01

    The ARM7 NEON processor with 128bit SIMD hardware accelerator requires a peak performance of 13.99 Mega Cycles per Second for MP3 stereo entertainment quality decoding. For similar compression bit rate, OGG and AAC is preferred over MP3. The Patent Cooperation Treaty Application dated 28/August/2012 describes an audio decompression scheme producing a sequence of interleaving "min to Max" and "Max to min" rising and falling segments. The number of interior audio samples bound by "min to Max" or "Max to min" can be {0|1|…|N} audio samples. The magnitudes of samples, including the bounding min and Max, are distributed as normalized constants within the 0 and 1 of the bounding magnitudes. The decompressed audio is then a "sequence of static segments" on a frame by frame basis. Some of these frames needed to be post processed to elevate high frequency. The post processing is compression efficiency neutral and the additional decoding complexity is only a small fraction of the overall decoding complexity without the need of extra hardware. Compression efficiency can be speculated as very high as source audio had been decimated and converted to a set of data with only "segment length and corresponding segment magnitude" attributes. The PCT describes how these two attributes are efficiently coded by the PCT innovative coding scheme. The PCT decoding efficiency is obviously very high and decoding latency is basically zero. Both hardware requirement and run time is at least an order of magnitude better than MP3 variants. The side benefit is ultra low power consumption on mobile device. The acid test on how such a simplistic waveform representation can indeed reproduce authentic decompressed quality is benchmarked versus OGG(aoTuv Beta 6.03) by three pair of stereo audio frames and one broadcast like voice audio frame with each frame consisting 2,028 samples at 44,100KHz sampling frequency.

  16. Decompressive craniectomy in diffuse traumatic brain injury.

    PubMed

    Cooper, D James; Rosenfeld, Jeffrey V; Murray, Lynnette; Arabi, Yaseen M; Davies, Andrew R; D'Urso, Paul; Kossmann, Thomas; Ponsford, Jennie; Seppelt, Ian; Reilly, Peter; Wolfe, Rory

    2011-04-21

    It is unclear whether decompressive craniectomy improves the functional outcome in patients with severe traumatic brain injury and refractory raised intracranial pressure. From December 2002 through April 2010, we randomly assigned 155 adults with severe diffuse traumatic brain injury and intracranial hypertension that was refractory to first-tier therapies to undergo either bifrontotemporoparietal decompressive craniectomy or standard care. The original primary outcome was an unfavorable outcome (a composite of death, vegetative state, or severe disability), as evaluated on the Extended Glasgow Outcome Scale 6 months after the injury. The final primary outcome was the score on the Extended Glasgow Outcome Scale at 6 months. Patients in the craniectomy group, as compared with those in the standard-care group, had less time with intracranial pressures above the treatment threshold (P<0.001), fewer interventions for increased intracranial pressure (P<0.02 for all comparisons), and fewer days in the intensive care unit (ICU) (P<0.001). However, patients undergoing craniectomy had worse scores on the Extended Glasgow Outcome Scale than those receiving standard care (odds ratio for a worse score in the craniectomy group, 1.84; 95% confidence interval [CI], 1.05 to 3.24; P=0.03) and a greater risk of an unfavorable outcome (odds ratio, 2.21; 95% CI, 1.14 to 4.26; P=0.02). Rates of death at 6 months were similar in the craniectomy group (19%) and the standard-care group (18%). In adults with severe diffuse traumatic brain injury and refractory intracranial hypertension, early bifrontotemporoparietal decompressive craniectomy decreased intracranial pressure and the length of stay in the ICU but was associated with more unfavorable outcomes. (Funded by the National Health and Medical Research Council of Australia and others; DECRA Australian Clinical Trials Registry number, ACTRN012605000009617.).

  17. Cardiovascular Pressures with Venous Gas Embolism and Decompression

    NASA Technical Reports Server (NTRS)

    Butler, B. D.; Robinson, R.; Sutton, T.; Kemper, G. B.

    1995-01-01

    Venous gas embolism (VGE) is reported with decompression to a decreased ambient pressure. With severe decompression, or in cases where an intracardiac septal defect (patent foramen ovale) exists, the venous bubbles can become arterialized and cause neurological decompression illness. Incidence rates of patent foramen ovale in the general population range from 25-34% and yet aviators, astronauts, and deepsea divers who have decompression-induced venous bubbles do not demonstrate neurological symptoms at these high rates. This apparent disparity may be attributable to the normal pressure gradient across the atria of the heart that must be reversed for there to be flow potency. We evaluated the effects of: venous gas embolism (0.025, 0.05 and 0.15 ml/ kg min for 180 min.) hyperbaric decompression; and hypobaric decompression on the pressure gradient across the left and right atria in anesthetized dogs with intact atrial septa. Left ventricular end-diastolic pressure was used as a measure of left atrial pressure. In a total of 92 experimental evaluations in 22 dogs, there were no reported reversals in the mean pressure gradient across the atria; a total of 3 transient reversals occurred during the peak pressure gradient changes. The reasons that decompression-induced venous bubbles do not consistently cause serious symptoms of decompression illness may be that the amount of venous gas does not always cause sufficient pressure reversal across a patent foramen ovale to cause arterialization of the venous bubbles.

  18. Colonic Fermentation Promotes Decompression sickness in Rats

    PubMed Central

    de Maistre, Sébastien; Vallée, Nicolas; Gempp, Emmanuel; Lambrechts, Kate; Louge, Pierre; Duchamp, Claude; Blatteau, Jean-Eric

    2016-01-01

    Massive bubble formation after diving can lead to decompression sickness (DCS). During dives with hydrogen as a diluent for oxygen, decreasing the body’s H2 burden by inoculating hydrogen-metabolizing microbes into the gut reduces the risk of DCS. So we set out to investigate if colonic fermentation leading to endogenous hydrogen production promotes DCS in fasting rats. Four hours before an experimental dive, 93 fasting rats were force-fed, half of them with mannitol and the other half with water. Exhaled hydrogen was measured before and after force-feeding. Following the hyperbaric exposure, we looked for signs of DCS. A higher incidence of DCS was found in rats force-fed with mannitol than in those force-fed with water (80%, [95%CI 56, 94] versus 40%, [95%CI 19, 64], p < 0.01). In rats force-fed with mannitol, metronidazole pretreatment reduced the incidence of DCS (33%, [95%CI 15, 57], p = 0.005) at the same time as it inhibited colonic fermentation (14 ± 35 ppm versus 118 ± 90 ppm, p = 0.0001). Pre-diveingestion of mannitol increased the incidence of DCS in fasting rats when colonic fermentation peaked during the decompression phase. More generally, colonic fermentation in rats on a normal diet could promote DCS through endogenous hydrogen production. PMID:26853722

  19. Bone microvascular flow differs from skin microvascular flow in response to head-down tilt.

    PubMed

    Howden, Michelle; Siamwala, Jamila H; Hargens, Alan R

    2017-10-01

    Loss of hydrostatic pressures in microgravity may alter skin and bone microvascular flows in the lower extremities and potentially reduce wound healing and bone fracture repair. The purpose of this study was to determine the rate at which skin and bone microvascular flows respond to head-down tilt (HDT). We hypothesized that microvascular flows in tibial bone and overlying skin would increase at different rates during HDT. Tibial bone and skin microvascular flows were measured simultaneously using photoplethysmography (PPG) in a total of 17 subjects during sitting (control posture), supine, 6° HDT, 15° HDT, and 30° HDT postures in random order. With greater angles of HDT, bone microvascular flow increased significantly, but skin microvascular flow did not change. Tibial bone microvascular flow increased from the sitting control posture (0.77 ± 0.41 V) to supine (1.95 ± 1.01 V, P = 0.001) and from supine posture to 15° HDT (3.74 ± 2.43 V, P = 0.004) and 30° HDT (3.91 ± 2.68 V, P = 0.006). Skin microvascular flow increased from sitting (0.703 ± 0.75 V) to supine (2.19 ± 1.72 V, P = 0.02) but did not change from supine posture to HDT ( P = 1.0). We show for the first time that microcirculatory flows in skin and bone of the leg respond to simulated microgravity at different rates. These altered levels of blood perfusion may affect rates of wound and bone fracture healing in spaceflight. NEW & NOTEWORTHY Our data show that bone microvascular flow increases more than cutaneous blood flow with greater degrees of head-down tilt. A higher level of perfusion in bone may give insight into the bone mineral density loss in lower extremities of astronauts and why similar tissue degradation is not observed in the skin of the same areas. Copyright © 2017 the American Physiological Society.

  20. Microvascular Targets for Anti-Fibrotic Therapeutics

    PubMed Central

    Pu, Kai-Ming T.; Sava, Parid; Gonzalez, Anjelica L.

    2013-01-01

    Fibrosis is characterized by excessive extracellular matrix deposition and is the pathological outcome of repetitive tissue injury in many disorders. The accumulation of matrix disrupts the structure and function of the native tissue and can affect multiple organs including the lungs, heart, liver, and skin. Unfortunately, current therapies against the deadliest and most common fibrosis are ineffective. The pathogenesis of fibrosis is the result of aberrant wound healing, therefore, the microvasculature plays an important role, contributing through regulation of leukocyte recruitment, inflammation, and angiogenesis. Further exacerbating the condition, microvascular endothelial cells and pericytes can transdifferentiate into matrix depositing myofibroblasts. The contribution of the microvasculature to fibrotic progression makes its cellular components and acellular products attractive therapeutic targets. In this review, we examine many of the cytokine, matrix, and cellular microvascular components involved in fibrosis and discuss their potential as targets for fibrotic therapies with a particular focus on developing nanotechnologies. PMID:24348218

  1. Microvascular lesions of the true vocal fold.

    PubMed

    Postma, G N; Courey, M S; Ossoff, R H

    1998-06-01

    Microvascular lesions, also called varices or capillary ectasias, in contrast to vocal fold polyps with telangiectatic vessels, are relatively small lesions arising from the microcirculation of the vocal fold. Varices are most commonly seen in female professional vocalists and may be secondary to repetitive trauma, hormonal variations, or repeated inflammation. Microvascular lesions may either be asymptomatic or cause frank dysphonia by interrupting the normal vibratory pattern, mass, or closure of the vocal folds. They may also lead to vocal fold hemorrhage, scarring, or polyp formation. Laryngovideostroboscopy is the key in determining the functional significance of vocal fold varices. Management of patients with a varix includes medical therapy, speech therapy, and occasionally surgical vaporization. Indications for surgery are recurrent hemorrhage, enlargement of the varix, development of a mass in conjunction with the varix or hemorrhage, and unacceptable dysphonia after maximal medical and speech therapy due to a functionally significant varix.

  2. Microvascular Anastomosis: Proposition of a Learning Curve.

    PubMed

    Mokhtari, Pooneh; Tayebi Meybodi, Ali; Benet, Arnau; Lawton, Michael T

    2018-04-14

    Learning to perform a microvascular anastomosis is one of the most difficult tasks in cerebrovascular surgery. Previous studies offer little regarding the optimal protocols to maximize learning efficiency. This failure stems mainly from lack of knowledge about the learning curve of this task. To delineate this learning curve and provide information about its various features including acquisition, improvement, consistency, stability, and recall. Five neurosurgeons with an average surgical experience history of 5 yr and without any experience in bypass surgery performed microscopic anastomosis on progressively smaller-caliber silastic tubes (Biomet, Palm Beach Gardens, Florida) during 24 consecutive sessions. After a 1-, 2-, and 8-wk retention interval, they performed recall test on 0.7-mm silastic tubes. The anastomoses were rated based on anastomosis patency and presence of any leaks. Improvement rate was faster during initial sessions compared to the final practice sessions. Performance decline was observed in the first session of working on a smaller-caliber tube. However, this rapidly improved during the following sessions of practice. Temporary plateaus were seen in certain segments of the curve. The retention interval between the acquisition and recall phase did not cause a regression to the prepractice performance level. Learning the fine motor task of microvascular anastomosis adapts to the basic rules of learning such as the "power law of practice." Our results also support the improvement of performance during consecutive sessions of practice. The objective evidence provided may help in developing optimized learning protocols for microvascular anastomosis.

  3. A review of microvascular ear replantation.

    PubMed

    Jung, Sung Won; Lee, Junsang; Oh, Suk Joon; Koh, Sung Hoon; Chung, Chul Hoon; Lee, Jong Wook

    2013-03-01

    Microvascular ear replantation is a significant challenge because of the small size of the vessels and the fact that traumatic amputations are frequently avulsed. The zone of trauma is therefore extended and the primary repair of the injured vessel is rendered unlikely. The purpose of this study is to review the literature of ear replantation. A review of the relevant literature that has been published since 1980 revealed 47 cases reported in 37 publications. We present 5 cases from our own experience and analyze a total 52 cases of microvascular ear replantation. The patient's age, sex, degree of amputation, cause of injury, ischemic time, method of arterial and venous anastomosis, complications, any additional outflow used, postoperative medications, the requirement for transfusions, and the number of hospital admission days are described. Successful microvascular ear replantations require anastomosis of the vessels if possible. Rather than a vein graft, primary repair of the vessels, or at least pedicled repair of the artery, should be considered to ensure flap survival. In addition, vein repair should be considered if possible to ensure the secure drainage of blood from the replant. With secure circulation, the replant can survive, resulting in a very satisfactory outcome. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  4. Ambulation Increases Decompression Sickness in Spacewalk Simulations

    NASA Technical Reports Server (NTRS)

    Pollock, N. W.; Natoli, M. J.; Conkin, J.; Wessel, J. H., III; Gernhardt, M. L.

    2014-01-01

    Musculoskeletal activity has the potential to both improve and compromise decompression safety. Exercise enhances inert gas elimination during oxygen breathing prior to decompression (prebreathe), but it may also promote bubble nuclei formation (nucleation), which can lead to gas phase separation and bubble growth and increase the risk of decompression sickness (DCS). The timing, pattern and intensity of musculoskeletal activity and the level of tissue supersaturation may be critical to the net effect. Understanding the relationships is important to evaluate exercise prebreathe protocols and quantify decompression risk in gravity and microgravity environments. Data gathered during NASA's Prebreathe Reduction Program (PRP) studies combined oxygen prebreathe and exercise followed by low pressure (4.3 psi; altitude equivalent of 30,300 ft [9,235 m]) microgravity simulation to produce two protocols used by astronauts preparing for extravehicular activity. Both the Phase II/CEVIS (cycle ergometer vibration isolation system) and ISLE (in-suit light exercise) trials eliminated ambulation to more closely simulate the microgravity environment. The CEVIS results (35 male, 10 female) serve as control data for this NASA/Duke study to investigate the influence of ambulation exercise on bubble formation and the subsequent risk of DCS. METHODS Four experiments will replicate the CEVIS exercise-enhanced oxygen prebreathe protocol, each with a different exception. The first of these is currently underway. Experiment 1 - Subjects complete controlled ambulation (walking in place with fixed cadence and step height) during both preflight and at 4.3 psi instead of remaining nonambulatory throughout. Experiment 2 - Subjects remain non-ambulatory during the preflight period and ambulatory at 4.3 psi. Experiment 3 - Subjects ambulate during the preflight period and remain non-ambulatory at 4.3 psi. Experiment 4 - The order of heavy and light exercise employed in the CEVIS protocol is

  5. Threshold altitude resulting in decompression sickness

    NASA Technical Reports Server (NTRS)

    Kumar, K. V.; Waligora, James M.; Calkins, Dick S.

    1990-01-01

    A review of case reports, hypobaric chamber training data, and experimental evidence indicated that the threshold for incidence of altitude decompression sickness (DCS) was influenced by various factors such as prior denitrogenation, exercise or rest, and period of exposure, in addition to individual susceptibility. Fitting these data with appropriate statistical models makes it possible to examine the influence of various factors on the threshold for DCS. This approach was illustrated by logistic regression analysis on the incidence of DCS below 9144 m. Estimations using these regressions showed that, under a noprebreathe, 6-h exposure, simulated EVA profile, the threshold for symptoms occurred at approximately 3353 m; while under a noprebreathe, 2-h exposure profile with knee-bends exercise, the threshold occurred at 7925 m.

  6. [Decompression problems in diving in mountain lakes].

    PubMed

    Bühlmann, A A

    1989-08-01

    The relationship between tolerated high-pressure tissue nitrogen and ambient pressure is practically linear. The tolerated nitrogen high pressure decreases at altitude, as the ambient pressure is lower. Additionally, tissues with short nitrogen half-times have a higher tolerance than tissues which retain nitrogen for longer duration. For the purpose of determining safe decompression routines, the human body can be regarded as consisting of 16 compartments with half-times from 4 to 635 minutes for nitrogen. The coefficients for calculation of the tolerated nitrogen-high pressure in the tissues can be deduced directly from the half-times for nitrogen. We show as application the results of 573 simulated air dives in the pressure-chamber and 544 real dives in mountain lakes in Switzerland (1400-2600 m above sea level) and in Lake Titicaca (3800 m above sea level). They are in accordance with the computed limits of tolerance.

  7. Transcranial Doppler ultrasound and the etiology of neurologic decompression sickness during altitude decompression

    NASA Technical Reports Server (NTRS)

    Norfleet, W. T.; Powell, M. R.; Kumar, K. Vasantha; Waligora, J.

    1993-01-01

    The presence of gas bubbles in the arterial circulation can occur from iatrogenic mishaps, cardiopulmonary bypass devices, or following decompression, e.g., in deep-sea or SCUBA diving or in astronauts during extravehicular activities (EVA). We have examined the pathophysiology of neurological decompression sickness in human subjects who developed a large number of small gas bubbles in the right side of the heart as a result of hypobaric exposures. In one case, gas bubbles were detected in the middle cerebral artery (MCA) and the subject developed neurological symptoms; a 'resting' patent foramen ovalae (PFO) was found upon saline contrast echocardiography. A PFO was also detected in another individual who developed Spencer Grade 4 precordial Doppler ultrasound bubbles, but no evidence was seen of arterialization of bubbles upon insonation of either the MCA or common carotid artery. The reason for this difference in the behavior of intracardiac bubbles in these two individuals is not known. To date, we have not found evidence of right-to-left shunting of bubbles through pulmonary vasculature. The volume of gas bubbles present following decompression is examined and compared with the number arising from saline contrast injection. The estimates are comparable.

  8. [Patent foramen ovale and decompression illness in divers].

    PubMed

    Sivertsen, Wiebke; Risberg, Jan; Norgård, Gunnar

    2010-04-22

    About 25 % of the population has patent foramen ovale, and the condition has been assumed to be a causal factor in decompressive illness. Transcatheter closure is possible and is associated with a relatively low risk, but it has not been clarified whether there is an indication for assessment and treatment of the condition in divers. The present study explored a possible relationship between a patent foramen ovale and the risk for decompression illness in divers, if there are categories of divers that should be screened for the condition and what advice should be given to divers with this condition. The review is based on literature identified through a search in Pubmed and the authors' long clinical experience in the field. The risk of decompression illness for divers with a persistent foramen ovale is about five times higher than that in divers without this condition, but the absolute risk for decompression illness is only 2.5 after 10,000 dives. A causal association has not been shown between patent foramen ovale and decompression illness. Even if closure of patent foramen ovale may be done with relatively small risk, the usefulness of the procedure has not been documented in divers. We do not recommend screening for patent foramen ovale in divers because the absolute risk of decompression illness is small and transcatheter closure is only indicated after decompression illness in some occupational divers.

  9. Decompression sickness ('the bends') in sea turtles.

    PubMed

    García-Párraga, D; Crespo-Picazo, J L; de Quirós, Y Bernaldo; Cervera, V; Martí-Bonmati, L; Díaz-Delgado, J; Arbelo, M; Moore, M J; Jepson, P D; Fernández, Antonio

    2014-10-16

    Decompression sickness (DCS), as clinically diagnosed by reversal of symptoms with recompression, has never been reported in aquatic breath-hold diving vertebrates despite the occurrence of tissue gas tensions sufficient for bubble formation and injury in terrestrial animals. Similarly to diving mammals, sea turtles manage gas exchange and decompression through anatomical, physiological, and behavioral adaptations. In the former group, DCS-like lesions have been observed on necropsies following behavioral disturbance such as high-powered acoustic sources (e.g. active sonar) and in bycaught animals. In sea turtles, in spite of abundant literature on diving physiology and bycatch interference, this is the first report of DCS-like symptoms and lesions. We diagnosed a clinico-pathological condition consistent with DCS in 29 gas-embolized loggerhead sea turtles Caretta caretta from a sample of 67. Fifty-nine were recovered alive and 8 had recently died following bycatch in trawls and gillnets of local fisheries from the east coast of Spain. Gas embolization and distribution in vital organs were evaluated through conventional radiography, computed tomography, and ultrasound. Additionally, positive response following repressurization was clinically observed in 2 live affected turtles. Gas embolism was also observed postmortem in carcasses and tissues as described in cetaceans and human divers. Compositional gas analysis of intravascular bubbles was consistent with DCS. Definitive diagnosis of DCS in sea turtles opens a new era for research in sea turtle diving physiology, conservation, and bycatch impact mitigation, as well as for comparative studies in other air-breathing marine vertebrates and human divers.

  10. Bulbar conjunctival microvascular responses in dry eye

    PubMed Central

    Chen, Wan; Batawi, Hatim Ismail M.; Alava, Jimmy R.; Galor, Anat; Yuan, Jin; Sarantopoulos, Constantine D.; McClellan, Allison L.; Feuer, William J.; Levitt, Roy C.; Wang, Jianhua

    2017-01-01

    Purpose Conjunctival microvascular responses may be a surrogate metric of efferent neural pathway function innervating the ocular surface as changes in blood flow occur within seconds after a stimulus. As somatosensory dysfunction may partially underlie dry eye (DE), in this study we evaluate whether bulbar conjunctival microvascular alterations correlate with various aspects of DE. Methods Fifty-six DE patients were prospectively recruited from a Veterans Affairs ophthalmology clinic over an 11-month period. DE symptoms and ocular pain were assessed along with DE signs. A novel functional slit lamp biomicroscope (FSLB) was used to image the temporal bulbar conjunctiva from the right eye before and after central corneal stimulation with an air puff. Blood flow velocities were measured and noninvasive microvascular perfusion maps (nMPMs) were created. Results The bulbar blood flow velocity was 0.50±0.15 mm/s at baseline and increased to 0.55±0.17 mm/s after stimulation (P<0.001); the average change in velocity was 0.05±0.09. nMPMs values and venule diameter, on the other hand, did not significantly increase after stimulation (1.64±0.004 at baseline, 1.65±0.04 after stimulation, P=0.22 and 22.13±1.84 m at baseline, 22.21±2.04 μm after stimulation, P=0.73, respectively). Baseline blood flow velocity positively associated with Schirmer scores (r=0.40, P=0.002). Those with higher self-rated wind hyperalgesia demonstrated less change in blood flow velocity (r= −0.268, P=0.046) after air stimulation on the central cornea. Conclusion Conjunctival blood flow velocity, but not vessel diameter or complexity, increases after wind stimuli. Baseline flow positively correlated with Schirmer scores while change in flow negatively correlated with self-reported wind hyperalgesia. PMID:28042094

  11. Treatment of Angina and Microvascular Coronary Dysfunction

    PubMed Central

    Samim, Arang; Nugent, Lynn; Mehta, Puja K.; Shufelt, Chrisandra; Merz, C. Noel Bairey

    2014-01-01

    Opinion statement Microvascular coronary dysfunction (MCD) is an increasingly recognized cause of cardiac ischemia and angina, more commonly diagnosed in women. Patients with MCD present with the triad of persistent chest pain, ischemic changes on stress testing, and no obstructive coronary artery disease (CAD) on cardiac catheterization. Data from National Heart, Lung and Blood Institute (NHLBI)-sponsored Women’s Ischemia Syndrome Evaluation (WISE) study has shown that the diagnosis of MCD is not benign, with a 2.5% annual risk of adverse cardiac events including myocardial infarction, stroke, congestive heart failure, or death. The gold standard diagnostic test for MCD is an invasive coronary reactivity test (CRT), which uses acetylcholine, adenosine, and nitroglycerin to test the endothelial dependent and independent, microvascular and macrovascular coronary function. The CRT allows for diagnostic and treatment options as well as further risk stratifying patients for future cardiovascular events. Treatment of angina and MCD should be aimed at ischemia disease management to reduce risk of adverse cardiac events, ameliorating symptoms to improve quality of life, and to decrease the morbidity from unnecessary and repeated cardiac catheterization in patients with open coronary arteries. A comprehensive treatment approach aimed at risk factor managment, including lifestyle counseling regarding smoking cessation, nutrition and physical activity should be initiated. Current pharmacotherapy for MCD can include the treatment of microvascular endothelial dysfunction (statins, angiotensin-converting enzyme inhibitor, low dose aspirin), as well as treatment for angina and myocardial ischemia (beta blockers, calcium channel blockers, nitrates, ranolazine). Additional symptom management techniques can include tri-cyclic medication, enhanced external counterpulsation, autogenic training, and spinal cord stimulation. While our current therapies are effective in the treatment

  12. Influenza Infects Lung Microvascular Endothelium Leading to Microvascular Leak: Role of Apoptosis and Claudin-5

    PubMed Central

    Armstrong, Susan M.; Wang, Changsen; Tigdi, Jayesh; Si, Xiaoe; Dumpit, Carlo; Charles, Steffany; Gamage, Asela; Moraes, Theo J.; Lee, Warren L.

    2012-01-01

    Severe influenza infections are complicated by acute lung injury, a syndrome of pulmonary microvascular leak. The pathogenesis of this complication is unclear. We hypothesized that human influenza could directly infect the lung microvascular endothelium, leading to loss of endothelial barrier function. We infected human lung microvascular endothelium with both clinical and laboratory strains of human influenza. Permeability of endothelial monolayers was assessed by spectrofluorimetry and by measurement of the transendothelial electrical resistance. We determined the molecular mechanisms of flu-induced endothelial permeability and developed a mouse model of severe influenza. We found that both clinical and laboratory strains of human influenza can infect and replicate in human pulmonary microvascular endothelium, leading to a marked increase in permeability. This was caused by apoptosis of the lung endothelium, since inhibition of caspases greatly attenuated influenza-induced endothelial leak. Remarkably, replication-deficient virus also caused a significant degree of endothelial permeability, despite displaying no cytotoxic effects to the endothelium. Instead, replication-deficient virus induced degradation of the tight junction protein claudin-5; the adherens junction protein VE-cadherin and the actin cytoskeleton were unaffected. Over-expression of claudin-5 was sufficient to prevent replication-deficient virus-induced permeability. The barrier-protective agent formoterol was able to markedly attenuate flu-induced leak in association with dose-dependent induction of claudin-5. Finally, mice infected with human influenza developed pulmonary edema that was abrogated by parenteral treatment with formoterol. Thus, we describe two distinct mechanisms by which human influenza can induce pulmonary microvascular leak. Our findings have implications for the pathogenesis and treatment of acute lung injury from severe influenza. PMID:23115643

  13. [Theoretical analysis of recompression-based therapies of decompression illness].

    PubMed

    Nikolaev, V P; Sokolov, G M; Komarevtsev, V N

    2011-01-01

    Theoretical analysis is concerned with the benefits of oxygen, air and nitrogen-helium-oxygen recompression schedules used to treat decompression illness in divers. Mathematical modeling of tissue bubbles dynamics during diving shows that one-hour oxygen recompression to 200 kPa does not diminish essentially the size of bubble enclosed in a layer that reduces tenfold the intensity of gas diffusion from bubbles. However, these bubbles dissolve fully in all the body tissues equally after 2-hr. air compression to 800 kPa and ensuing 2-d decompression by the Russian navy tables, and 1.5-hr. N-He-O2 compression to this pressure followed by 5-day decompression. The overriding advantage of the gas mixture recompression is that it obviates the narcotic action of nitrogen at the peak of chamber pressure and does not create dangerous tissue supersaturation and conditions for emergence of large bubbles at the end of decompression.

  14. Listeriolysin O mediates cytotoxicity against human brain microvascular

    USDA-ARS?s Scientific Manuscript database

    Penetration of the brain microvascular endothelial layer is one of the routes L. monocytogenes use to breach the blood-brain barrier. Because host factors in the blood severely limit direct invasion of human brain microvascular endothelial cells (HBMECs) by L. monocytogenes, alternative mechanisms m...

  15. Bifurcations: Focal Points of Particle Adhesion in Microvascular Networks

    PubMed Central

    Prabhakarpandian, Balabhaskar; Wang, Yi; Rea-Ramsey, Angela; Sundaram, Shivshankar; Kiani, Mohammad F.; Pant, Kapil

    2011-01-01

    Objective Particle adhesion in vivo is dependent on microcirculation environment which features unique anatomical (bifurcations, tortuosity, cross-sectional changes) and physiological (complex hemodynamics) characteristics. The mechanisms behind these complex phenomena are not well understood. In this study, we used a recently developed in vitro model of microvascular networks, called Synthetic Microvascular Network, for characterizing particle adhesion patterns in the microcirculation. Methods Synthetic microvascular networks were fabricated using soft lithography processes followed by particle adhesion studies using avidin and biotin-conjugated microspheres. Particle adhesion patterns were subsequently analyzed using CFD based modeling. Results Experimental and modeling studies highlighted the complex and heterogeneous fluid flow patterns encountered by particles in microvascular networks resulting in significantly higher propensity of adhesion (>1.5X) near bifurcations compared to the branches of the microvascular networks. Conclusion Bifurcations are the focal points of particle adhesion in microvascular networks. Changing flow patterns and morphology near bifurcations are the primary factors controlling the preferential adhesion of functionalized particles in microvascular networks. Synthetic microvascular networks provide an in vitro framework for understanding particle adhesion. PMID:21418388

  16. You’re the Flight Surgeon: Pulmonary Decompression Sickness

    DTIC Science & Technology

    2008-06-01

    follow-up of this patient Diagnosis: Decompression sickness (DeS) with pulmonary symptoms (Type Il DeS, older nomenclature). Treatment: Hyperbaric ...is quite clear thai any case of suspected decompression sickness in the USAF be discussed with the hyperbariC medicine specialists at Brooks City...physician in as respectful manner as you can that you suspect the patient’s condition is likely related to his hypobaric exposure. B. Agree with

  17. Sub-diffraction Imaging via Surface Plasmon Decompression

    DTIC Science & Technology

    2014-06-08

    of the local wavelength of a surface plasmon polariton supported by two adjoining curved metal surfaces. The views, opinions and/or findings...adiabatic decompression of the local wavelength of a surface plasmon polariton supported by two adjoining curved metal surfaces. Conference Name...diffraction imaging based on a process of adiabatic decompression of the local wavelength of a surface plasmon polariton supported by two adjoining curved

  18. 29 CFR Appendix A to Subpart S of... - Decompression Tables

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... working period at 20 pounds gauge. Decompression Table No. 1: 20 pounds for 4 hours, total decompression... minutes per pound. Stage 2 (final) elapsed time 40 Total time 43 Example No. 2: 5-hour working period at... pressure p.s.i.g. Working period hours 1/2 1 11/2 2 3 4 5 6 7 8 Over 8 9 to 12 3 3 3 3 3 3 3 3 3 3 3 14 6 6...

  19. The probability and severity of decompression sickness

    PubMed Central

    Hada, Ethan A.; Vann, Richard D.; Denoble, Petar J.

    2017-01-01

    Decompression sickness (DCS), which is caused by inert gas bubbles in tissues, is an injury of concern for scuba divers, compressed air workers, astronauts, and aviators. Case reports for 3322 air and N2-O2 dives, resulting in 190 DCS events, were retrospectively analyzed and the outcomes were scored as (1) serious neurological, (2) cardiopulmonary, (3) mild neurological, (4) pain, (5) lymphatic or skin, and (6) constitutional or nonspecific manifestations. Following standard U.S. Navy medical definitions, the data were grouped into mild—Type I (manifestations 4–6)–and serious–Type II (manifestations 1–3). Additionally, we considered an alternative grouping of mild–Type A (manifestations 3–6)–and serious–Type B (manifestations 1 and 2). The current U.S. Navy guidance allows for a 2% probability of mild DCS and a 0.1% probability of serious DCS. We developed a hierarchical trinomial (3-state) probabilistic DCS model that simultaneously predicts the probability of mild and serious DCS given a dive exposure. Both the Type I/II and Type A/B discriminations of mild and serious DCS resulted in a highly significant (p << 0.01) improvement in trinomial model fit over the binomial (2-state) model. With the Type I/II definition, we found that the predicted probability of ‘mild’ DCS resulted in a longer allowable bottom time for the same 2% limit. However, for the 0.1% serious DCS limit, we found a vastly decreased allowable bottom dive time for all dive depths. If the Type A/B scoring was assigned to outcome severity, the no decompression limits (NDL) for air dives were still controlled by the acceptable serious DCS risk limit rather than the acceptable mild DCS risk limit. However, in this case, longer NDL limits were allowed than with the Type I/II scoring. The trinomial model mild and serious probabilities agree reasonably well with the current air NDL only with the Type A/B scoring and when 0.2% risk of serious DCS is allowed. PMID:28296928

  20. Decompression to altitude: assumptions, experimental evidence, and future directions.

    PubMed

    Foster, Philip P; Butler, Bruce D

    2009-02-01

    Although differences exist, hypobaric and hyperbaric exposures share common physiological, biochemical, and clinical features, and their comparison may provide further insight into the mechanisms of decompression stress. Although altitude decompression illness (DCI) has been experienced by high-altitude Air Force pilots and is common in ground-based experiments simulating decompression profiles of extravehicular activities (EVAs) or astronauts' space walks, no case has been reported during actual EVAs in the non-weight-bearing microgravity environment of orbital space missions. We are uncertain whether gravity influences decompression outcomes via nitrogen tissue washout or via alterations related to skeletal muscle activity. However, robust experimental evidence demonstrated the role of skeletal muscle exercise, activities, and/or movement in bubble formation and DCI occurrence. Dualism of effects of exercise, positive or negative, on bubble formation and DCI is a striking feature in hypobaric exposure. Therefore, the discussion and the structure of this review are centered on those highlighted unresolved topics about the relationship between muscle activity, decompression, and microgravity. This article also provides, in the context of altitude decompression, an overview of the role of denitrogenation, metabolic gases, gas micronuclei, stabilization of bubbles, biochemical pathways activated by bubbles, nitric oxide, oxygen, anthropometric or physiological variables, Doppler-detectable bubbles, and potential arterialization of bubbles. These findings and uncertainties will produce further physiological challenges to solve in order to line up for the programmed human return to the Moon, the preparation for human exploration of Mars, and the EVAs implementation in a non-zero gravity environment.

  1. Decompression sickness in breath-hold divers: a review.

    PubMed

    Lemaitre, Frederic; Fahlman, Andreas; Gardette, Bernard; Kohshi, Kiyotaka

    2009-12-01

    Although it has been generally assumed that the risk of decompression sickness is virtually zero during a single breath-hold dive in humans, repeated dives may result in a cumulative increase in the tissue and blood nitrogen tension. Many species of marine mammals perform extensive foraging bouts with deep and long dives interspersed by a short surface interval, and some human divers regularly perform repeated dives to 30-40 m or a single dive to more than 200 m, all of which may result in nitrogen concentrations that elicit symptoms of decompression sickness. Neurological problems have been reported in humans after single or repeated dives and recent necropsy reports in stranded marine mammals were suggestive of decompression sickness-like symptoms. Modelling attempts have suggested that marine mammals may live permanently with elevated nitrogen concentrations and may be at risk when altering their dive behaviour. In humans, non-pathogenic bubbles have been recorded and symptoms of decompression sickness have been reported after repeated dives to modest depths. The mechanisms implicated in these accidents indicate that repeated breath-hold dives with short surface intervals are factors that predispose to decompression sickness. During deep diving, the effect of pulmonary shunts and/or lung collapse may play a major role in reducing the incidence of decompression sickness in humans and marine mammals.

  2. Edema and elasticity of a fronto-temporal decompressive craniectomy

    PubMed Central

    Takada, Daikei; Nagai, Hidemasa; Moritake, Kouzo; Akiyama, Yasuhiko

    2012-01-01

    Background: Decompressive craniectomy is undertaken for relief of brain herniation caused by acute brain swelling. Brain stiffness can be estimated by palpating the decompressive cranial defect and can provide some relatively subjective information to the neurosurgeon to help guide care. The goal of the present study was to objectively evaluate transcutaneous stiffness of the cranial defect using a tactile resonance sensor and to describe the values in patients with a decompressive window in order to characterize the clinical association between brain edema and stiffness. Methods: Data were prospectively collected from 13 of 37 patients who underwent a decompressive craniectomy in our hospital during a 5-year period. Transcutaneous stiffness was measured as change in frequency and as elastic modulus. Results: Stiffness variables of the decompressive site were measured without any adverse effect and subsequent calculations revealed change in frequency = 101.71 ± 36.42 Hz, and shear elastic modulus = 1.99 ± 1.11 kPa. Conclusions: The elasticity of stiffness of a decompressive site correlated with brain edema, cisternal cerebrospinal fluid pressure, and brain shift, all of which are related to acute brain edema. PMID:22347679

  3. Piezosurgery in Modified Pterional Orbital Decompression Surgery in Graves Disease.

    PubMed

    Grauvogel, Juergen; Scheiwe, Christian; Masalha, Waseem; Jarc, Nadja; Grauvogel, Tanja; Beringer, Andreas

    2017-10-01

    Piezosurgery uses microvibrations to selectively cut bone, preserving the adjacent soft tissue. The present study evaluated the use of piezosurgery for bone removal in orbital decompression surgery in Graves disease via a modified pterional approach. A piezosurgical device (Piezosurgery medical) was used in 14 patients (20 orbits) with Graves disease who underwent orbital decompression surgery in additional to drills and rongeurs for bone removal of the lateral orbital wall and orbital roof. The practicability, benefits, and drawbacks of this technique in orbital decompression surgery were recorded. Piezosurgery was evaluated with respect to safety, preciseness of bone cutting, and preservation of the adjacent dura and periorbita. Preoperative and postoperative clinical outcome data were assessed. The orbital decompression surgery was successful in all 20 orbits, with good clinical outcomes and no postoperative complications. Piezosurgery proved to be a safe tool, allowing selective bone cutting with no damage to the surrounding soft tissue structures. However, there were disadvantages concerning the intraoperative handling in the narrow space and the efficiency of bone removal was limited in the orbital decompression surgery compared with drills. Piezosurgery proved to be a useful tool in bone removal for orbital decompression in Graves disease. It is safe and easy to perform, without any danger of damage to adjacent tissue because of its selective bone-cutting properties. Nonetheless, further development of the device is necessary to overcome the disadvantages in intraoperative handling and the reduced bone removal rate. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Prefabricated microvascular autograft in tracheal reconstruction.

    PubMed

    Fayad, J; Kuriloff, D B

    1994-10-01

    Tracheal reconstruction continues to be a challenge in head and neck surgery. Numerous techniques, including the use of alloplasts, composite grafts, and staged laryngotracheal troughs, have met with limited success because of implant exposure, infection, persistent granulation tissue, and eventual restenosis. With recently introduced techniques for soft-tissue molding, bone induction with bone morphogenetic protein, and microvascular free tissue transfer, a rodent model was developed to create a well-vascularized tracheal autograft. In this model, a rigid tube having the same dimensions and flexibility as the native trachea was created by wrapping a cylindrical silicone tracheal mold with a layer of vascularized adductor thigh muscle pedicled on the femoral vessels in the groin. Tracheal rings were created by filing transverse troughs in the muscle bed with bone morphogenetic protein-primed demineralized bone matrix before wrapping around the silicone mold. Grafts harvested at 2 weeks demonstrated rigid skeletal support provided by heterotopic bone formation in the form of rings and a smooth inner lining produced by fibroplasia. Bone transformation was controlled and restricted to the muscle troughs, allowing intervening regions of soft tissue and thus producing a flexible neotrachia. With this model, a homologous, vascularized tracheal autograft capable of microvascular free tissue transfer was fabricated based on the femoral vessels. Prefabrication of composite grafts, through the use of soft-tissue molding, bone induction, and subsequent free tissue transfer, has an unlimited potential for use in head and neck reconstruction.

  5. Arthroscopic Decompression for a Giant Meniscal Cyst.

    PubMed

    Ohishi, Tsuyoshi; Suzuki, Daisuke; Matsuyama, Yukihiro

    2016-01-01

    The authors report the case of a giant medial meniscal cyst in an osteoarthritic knee of an 82-year-old woman that was successfully treated with only arthroscopic cyst decompression. The patient noticed a painful mass on the medial side of the right knee that had been gradually growing for 5 years. Magnetic resonance imaging showed an encapsulated large medial cystic mass measuring 80×65×40 mm that was adjacent to the medial meniscus. An accompanying horizontal tear was also detected in the middle and posterior segments of the meniscus. The medial meniscus was resected up to the capsular attachment to create bidirectional flow between the joint and the cyst with arthroscopic surgery. Magnetic resonance imaging performed 14 months postoperatively showed that the cyst had completely disappeared, and no recurrence was observed during a 2-year follow-up period. An excellent result could be obtained by performing limited meniscectomy to create a channel leading to the meniscal cyst, even though the cyst was large. Among previously reported cases of meniscal cysts, this case is the largest to be treated arthroscopically without open excision. Copyright 2016, SLACK Incorporated.

  6. Use of ultrasound in altitude decompression modeling

    NASA Technical Reports Server (NTRS)

    Olson, Robert M.; Pilmanis, Andrew A.

    1993-01-01

    A model that predicts the probability of developing decompression sickness (DCS) with various denitrogenation schedules is being developed by the Armstrong Laboratory, using human data from previous exposures. It was noted that refinements are needed to improve the accuracy and scope of the model. A commercially developed ultrasonic echo imaging system is being used in this model development. Using this technique, bubbles images from a subject at altitude can be seen in the gall bladder, hepatic veins, vena cava, and chambers of the heart. As judged by their motion and appearance in the vena cava, venous bubbles near the heart range in size from 30 to 300 M. The larger bubbles skim along the top, whereas the smaller ones appear as faint images near the bottom of the vessel. Images from growing bubbles in a model altitude chamber indicate that they grow rapidly, going from 20 to 100 M in 3 sec near 30,000 ft altitude. Information such as this is valuable in verifying those aspects of the DCS model dealing with bubble size, their growth rate, and their site of origin.

  7. Decompressive craniectomy and CSF disorders in children.

    PubMed

    Manfiotto, Marie; Mottolese, Carmine; Szathmari, Alexandru; Beuriat, Pierre-Aurelien; Klein, Olivier; Vinchon, Matthieu; Gimbert, Edouard; Roujeau, Thomas; Scavarda, Didier; Zerah, Michel; Di Rocco, Federico

    2017-10-01

    Decompressive craniectomy (DC) is a lifesaving procedure but is associated to several post-operative complications, namely cerebrospinal fluid (CSF) dynamics impairment. The aim of this multicentric study was to evaluate the incidence of such CSF alterations after DC and review their impact on the overall outcome. We performed a retrospective multicentric study to analyze the CSF disorders occurring in children aged from 0 to 17 years who had undergone a DC for traumatic brain injury (TBI) in the major Departments of Pediatric Neurosurgery of France between January 2006 and August 2016. Out of 150 children, ranging in age between 7 months and 17 years, mean 10.75 years, who underwent a DC for TBI in 10 French pediatric neurosurgical centers. Sixteen (6 males, 10 females) (10.67%) developed CSF disorders following the surgical procedure and required an extrathecal CSF shunting. External ventricular drainage increased the risk of further complications, especially cranioplasty infection (p = 0.008). CSF disorders affect a minority of children after DC for TBI. They may develop early after the DC but they may develop several months after the cranioplasty (8 months), consequently indicating the necessity of clinical and radiological close follow-up after discharge from the neurosurgical unit. External ventricular drainage and permanent CSF shunt placement increase significantly the risk of cranioplasty infection.

  8. Crystallisation regimes and kinetics in experimentally decompressed dacitic magma

    NASA Astrophysics Data System (ADS)

    Blum-Oeste, N.; Schmidt, B. C.; Webb, S. L.

    2011-12-01

    Kinetic processes during magma ascent may have a strong influence on the eruption style. In water bearing dacitic magmas decompression induced exsolution of water and accompanying crystallisation of plagioclase are the main processes which drive the system towards a new equilibrium state. We present new data on the evolution of residual glass composition and crystal size distributions of plagioclase from decompression experiments. Experiments have been conducted in cold seal pressure vessels at 850°C on a natural dacite composition from Taapaca volcano (N. Chile). After an initial equilibration at 2kbar decompression rates between 6.3 and 450bar/h were applied to final pressures between 50 and 1550bar where samples were rapidly quenched. Complementary equilibrium experiments were done at corresponding pressures. The glass composition evolves from the initial state towards the equilibrium at the final pressure. The completeness of this re-equilibration depends on run duration and reaction rates. We introduce the "re-equilibration index" (REI), a fraction between 0 (initial state) and 1 (final state) which allows comparison of chemical components in terms of re-equilibration at different decompression rates. REI divided by the decompression duration gives the "re-equilibration rate" (RER). The REI varies among oxides and it decreases with increasing decompression rate. The highest REIs of ~0.9 have been found for MgO, K2O and Al2O3 at 6.3bar/h whereas Na2O shows the lowest number with 0.25 at this decompression rate. Towards faster decompression all REIs tend to decrease which shows a decreasing completeness of re-equilibration. At 450bar/h the highest REIs are ~0.25. RERs increase from below ~0.005/h at 6.3bar/h up to almost 0.08/h for Al2O3 at 450bar/h. The variability of RERs of different oxides also increases with decompression rates. At 450bar/h the RERs reach from <0.005/h up to 0.08/h. Although RERs strongly increase from low to high decompression rates, this

  9. Acute alcohol intoxication-induced microvascular leakage.

    PubMed

    Doggett, Travis M; Breslin, Jerome W

    2014-09-01

    Alcohol intoxication can increase inflammation and worsen injury, yet the mechanisms involved are not clear. We investigated whether acute alcohol intoxication increases microvascular permeability and investigated potential signaling mechanisms in endothelial cells that may be involved. Conscious rats received a 2.5 g/kg alcohol bolus via gastric catheters to produce acute intoxication. Microvascular leakage of intravenously administered fluorescein isothiocyanate (FITC)-conjugated albumin (FITC-albumin) from the mesenteric microcirculation was assessed by intravital microscopy. Endothelial-specific mechanisms were studied using cultured endothelial cell monolayers. Transendothelial electrical resistance (TER) served as an index of barrier function, before and after treatment with alcohol or its metabolite acetaldehyde. Pharmacologic agents were used to test the roles of alcohol metabolism, oxidative stress, p38 mitogen-activated protein kinase (MAPK), myosin light-chain kinase (MLCK), rho kinase (ROCK), and exchange protein activated by cAMP (Epac). VE-cadherin localization was investigated to assess junctional integrity. Rac1 and RhoA activation was assessed by ELISA assays. Alcohol significantly increased FITC-albumin extravasation from the mesenteric microcirculation. Alcohol also significantly decreased TER and disrupted VE-cadherin organization at junctions. Acetaldehyde significantly decreased TER, but inhibition of alcohol dehydrogenase or application of a superoxide dismutase mimetic failed to prevent alcohol-induced decreases in TER. Inhibition of p38 MAPK, but not MLCK or ROCK, significantly attenuated the alcohol-induced barrier dysfunction. Alcohol rapidly decreased GTP-bound Rac1 but not RhoA during the drop in TER. Activation of Epac increased TER, but did not prevent alcohol from decreasing TER. However, activation of Epac after initiation of alcohol-induced barrier dysfunction quickly resolved TER to baseline levels. Our results suggest that

  10. Dysphonia and dysphagia after anterior cervical decompression.

    PubMed

    Tervonen, Hanna; Niemelä, Mika; Lauri, Eija-Riitta; Back, Leif; Juvas, Anja; Räsänen, Pirjo; Roine, Risto P; Sintonen, Harri; Salmi, Tapani; Vilkman, S Erkki; Aaltonen, Leena-Maija

    2007-08-01

    In this paper, the authors investigate the effects of anterior cervical decompression (ACD) on swallowing and vocal function. The study comprised 114 patients who underwent ACD. The early group (50 patients) was examined immediately pre- and postoperatively, and the late group (64 patients) was examined at only 3 to 9 months postoperatively. Fifty age- and sex-matched patients from the Department of Otorhinolaryngology-Head and Neck Surgery who had not been intubated in the previous 5 years were used as a control group. All patients in the early and control groups were examined by a laryngologist; patients in the late group were examined by a laryngologist and a neurosurgeon. Videolaryngostroboscopy was performed in all members of the patient and control groups, and the function of the ninth through 12th cranial nerves were clinically evaluated. Data were collected concerning swallowing, voice quality, surgery results, and health-related quality of life. Patients with persistent dysphonia were referred for phoniatric evaluation and laryngeal electromyography (EMG). Those with persistent dysphagia underwent transoral endoscopic evaluation of swallowing function and videofluorography. Sixty percent of patients in the early group reported dysphonia and 69% reported dysphagia at the immediate postoperative visit. Unilateral vocal fold paresis occurred in 12%. The prevalence of both dysphonia and dysphagia decreased in both groups 3 to 9 months postoperatively. All six patients with vocal fold paresis in the early group recovered, and in the late group there were two cases of vocal fold paresis. The results of laryngeal EMG were abnormal in 14 of 16 patients with persistent dysphonia. Neither intraoperative factors nor age or sex had any effect on the occurrence of dysphonia, dysphagia, or vocal fold paresis. Most patients were satisfied with the surgical outcome. Dysphonia, dysphagia, and vocal fold paresis are common but usually transient complications of ACD

  11. Failure rate of prehospital chest decompression after severe thoracic trauma.

    PubMed

    Kaserer, Alexander; Stein, Philipp; Simmen, Hans-Peter; Spahn, Donat R; Neuhaus, Valentin

    2017-03-01

    Chest decompression can be performed by different techniques, like needle thoracocentesis (NT), lateral thoracostomy (LT), or tube thoracostomy (TT). The aim of this study was to report the incidence of prehospital chest decompression and to analyse the effectiveness of these techniques. In this retrospective case series study, all medical records of adult trauma patients undergoing prehospital chest decompression and admitted to the resuscitation area of a level-1 trauma center between 2009 and 2015 were reviewed and analysed. Only descriptive statistics were applied. In a 6-year period 24 of 2261 (1.1%) trauma patients had prehospital chest decompression. Seventeen patients had NT, six patients TT, one patient NT as well as TT, and no patients had LT. Prehospital successful release of a tension pneumothorax was reported by the paramedics in 83% (5/6) with TT, whereas NT was effective in 18% only (3/17). In five CT scans all thoracocentesis needles were either removed or extrapleural, one patient had a tension pneumothorax, and two patients had no pneumothorax. No NT or TT related complications were reported during hospitalization. Prehospital NT or TT is infrequently attempted in trauma patients. Especially NT is associated with a high failure rate of more than 80%, potentially due to an inadequate ratio between chest wall thickness and catheter length as previously published as well as a possible different pathophysiological cause of respiratory distress. Therefore, TT may be considered already in the prehospital setting to retain sufficient pleural decompression upon admission. Copyright © 2016. Published by Elsevier Inc.

  12. Decompressing recompression chamber attendants during Australian submarine rescue operations.

    PubMed

    Reid, Michael P; Fock, Andrew; Doolette, David J

    2017-09-01

    Inside chamber attendants rescuing survivors from a pressurised, distressed submarine may themselves accumulate a decompression obligation which may exceed the limits of Defense and Civil Institute of Environmental Medicine tables presently used by the Royal Australian Navy. This study assessed the probability of decompression sickness (P DCS ) for medical attendants supervising survivors undergoing oxygen-accelerated saturation decompression according to the National Oceanic and Atmospheric Administration (NOAA) 17.11 table. Estimated probability of decompression sickness (P DCS ), the units pulmonary oxygen toxicity dose (UPTD) and the volume of oxygen required were calculated for attendants breathing air during the NOAA table compared with the introduction of various periods of oxygen breathing. The P DCS in medical attendants breathing air whilst supervising survivors receiving NOAA decompression is up to 4.5%. For the longest predicted profile (830 minutes at 253 kPa) oxygen breathing at 30, 60 and 90 minutes at 132 kPa partial pressure of oxygen reduced the air-breathing-associated P DCS to less than 3.1 %, 2.1% and 1.4% respectively. The probability of at least one incident of DCS among attendants, with consequent strain on resources, is high if attendants breathe air throughout their exposure. The introduction of 90 minutes of oxygen breathing greatly reduces the probability of this interruption to rescue operations.

  13. Protein osmotic pressure gradients and microvascular reflection coefficients.

    PubMed

    Drake, R E; Dhother, S; Teague, R A; Gabel, J C

    1997-08-01

    Microvascular membranes are heteroporous, so the mean osmotic reflection coefficient for a microvascular membrane (sigma d) is a function of the reflection coefficient for each pore. Investigators have derived equations for sigma d based on the assumption that the protein osmotic pressure gradient across the membrane (delta II) does not vary from pore to pore. However, for most microvascular membranes, delta II probably does vary from pore to pore. In this study, we derived a new equation for sigma d. According to our equation, pore-to-pore differences in delta II increase the effect of small pores and decrease the effect of large pores on the overall membrane osmotic reflection coefficient. Thus sigma d for a heteroporous membrane may be much higher than previously derived equations indicate. Furthermore, pore-to-pore delta II differences increase the effect of plasma protein osmotic pressure to oppose microvascular fluid filtration.

  14. Microvascular temporalis fascia transfer for penile girth enhancement.

    PubMed

    Küçükçelebi, A; Ertaş, N M; Aydin, A; Eroğlu, A; Ozmen, E; Velidedeoğlu, H

    2001-07-01

    The authors report a 44-year-old man with inadequate penile girth that caused psychological problems. Using microvascular temporalis fascia transfer, they achieved satisfactory penile girth enhancement based on reliable vascularity in a single stage.

  15. Pulmonary microvascular cytology can detect tumor cells of intravascular lymphoma.

    PubMed

    Ishiguro, Takashi; Takayanagi, Noboru; Yanagisawa, Tsutomu; Kagiyama, Naho; Saito, Hiroo; Sugita, Yutaka; Kojima, Masaru

    2009-01-01

    A 68-year-old man was admitted to our hospital for indistinct consciousness, progressive dyspnea, night sweats and fever of 2 weeks duration. Hypoxemia, thrombocytopenia, and elevated serum lactate dehydrogenase were found. Computed tomography was negative except for a small bilateral pleural effusion. Chest perfusion scintigraphy showed inhomogeneous perfusion thought unlikely to be pulmonary artery thromboembolism. Intravascular large B-cell lymphoma was suspected, and a pulmonary microvascular cytology specimen was obtained that contained numerous large lymphoma cells. Because the patient's condition was rapidly deteriorating, we started chemotherapy on the basis of the pulmonary microvascular cytology findings, and he improved. Later, atypical lymphocytes similar to those in the pulmonary microvascular cytology specimen were found in a bone marrow specimen. He was diagnosed as having diffuse large B-cell lymphoma. Because lymphoma cells were found in the pulmonary microvasculature, intravascular lymphoma was also diagnosed. Pulmonary microvascular cytology was helpful to detect lymphoma cells in the pulmonary microvasculature.

  16. The Risks of Scuba Diving: A Focus on Decompression Illness

    PubMed Central

    2014-01-01

    Decompression Illness includes both Decompression Sickness (DCS) and Pulmonary Overinflation Syndrome (POIS), subsets of diving-related injury related to scuba diving. DCS is a condition in which gas bubbles that form while diving do not have adequate time to be resorbed or “off-gassed,” resulting in entrapment in specific regions of the body. POIS is due to an overly rapid ascent to the surface resulting in the rupture of alveoli and subsequent extravasation of air bubbles into tissue planes or even the cerebral circulation. Divers must always be cognizant of dive time and depth, and be trained in the management of decompression. A slow and controlled ascent, plus proper control of buoyancy can reduce the dangerous consequences of pulmonary barotrauma. The incidence of adverse effects can be diminished with safe practices, allowing for the full enjoyment of this adventurous aquatic sport. PMID:25478296

  17. Decompression sickness in simulated Apollo-Soyuz space missions

    NASA Technical Reports Server (NTRS)

    Cooke, J. P.; Robertson, W. G.

    1974-01-01

    Apollo-Soyuz docking module atmospheres were evaluated for incidence of decompression sickness in men simulating passage from the Russian spacecraft atmosphere, to the U.S. spacecraft atmosphere, and then to the American space suit pressure. Following 8 hr of 'shirtsleeve' exposure to 31:69::O2:N2 gas breathing mixture, at 10 psia, subjects were 'denitrogenated' for either 30 or 60 min with 100% O2 prior to decompression directly to 3.7 psia suit equivalent while performing exercise at fixed intervals. Five of 21 subjects experienced symptoms of decompression sickness after 60 min of denitrogenation compared to 6 among 20 subjects after 30 min of denitrogenation. A condition of Grade I bends was reported after 60 min of denitrogenation, and 3 of these 5 subjects noted the disappearance of all symptoms of bends at 3.7 psia. After 30 min of denitrogenation, 2 out of 6 subjects developed Grade II bends at 3.7 psia.

  18. Microvascular characteristics of the acoustic fats: Novel data suggesting taxonomic differences between deep and shallow-diving odontocetes.

    PubMed

    Gabler, Molly K; Gay, D Mark; Westgate, Andrew J; Koopman, Heather N

    2018-04-01

    Odontocetes have specialized mandibular fats, the extramandibular (EMFB) and intramandibular fat bodies (IMFB), which function as acoustic organs, receiving and channeling sound to the ear during hearing and echolocation. Recent strandings of beaked whales suggest that these fat bodies are susceptible to nitrogen (N 2 ) gas embolism and empirical evidence has shown that the N 2 solubility of these fat bodies is higher than that of blubber. Since N 2 gas will diffuse from blood into tissue at any blood/tissue interface and potentially form gas bubbles upon decompression, it is imperative to understand the extent of microvascularity in these specialized acoustic fats so that risk of embolism formation when diving can be estimated. Microvascular density was determined in the EMFB, IMFB, and blubber from 11 species representing three odontocete families. In all cases, the acoustic tissues had less (typically 1/3 to 1/2) microvasculature than did blubber, suggesting that capillary density in the acoustic tissues may be more constrained than in the blubber. However, even within these constraints there were clear phylogenetic differences. Ziphiid (Mesoplodon and Ziphius, 0.9 ± 0.4% and 0.7 ± 0.3% for EMFB and IMFB, respectively) and Kogiid families (1.2 ± 0.2% and 1.0 ± 0.01% for EMFB and IMFB, respectively) had significantly lower mean microvascular densities in the acoustic fats compared to the Delphinid species (Tursiops, Grampus, Stenella, and Globicephala, 1.3 ± 0.3% and 1.3 ± 0.3% for EMFB and IMFB, respectively). Overall, deep-diving beaked whales had less microvascularity in both mandibular fats and blubber compared to the shallow-diving Delphinids, which might suggest that there are differences in the N 2 dynamics associated with diving regime, phylogeny, and tissue type. These novel data should be incorporated into diving physiology models to further understand potential functional disruption of the acoustic tissues due to changes

  19. [A clinical study on different decompression methods in cervical spondylosis].

    PubMed

    Ma, Xun; Zhao, Xiao-fei; Zhao, Yi-bo

    2009-04-15

    To analyze the different decompression methods to treat cervical spondylosis based on imageological evaluation. Two hundred and sixty three consecutive patients with cervical spondylosis between Nov. 2004 and Oct. 2007 were involved in this study. Patients were distributed to different operation groups based on the preoperative imageological evaluation, including anterior or posterior decompression methods. The Anterior method is to use the discectomy of one to three segments, autogenous iliac graft or titanium mesh or cage fusion and titanium plate fixation, or subtotal vertebrectomy of one to two segments autogenous iliac graft or titanium mesh fusion and titanium plate fixation, or discectomy plus subtotal vertebrectomy, The posterior expansive single open door laminoplasty and other operation types. All the patients were divided into different groups by the preoperative imageological evaluation, age, sex and course of diseases. Then we collected each group's preoperative and postoperative JOA scores and mean improvement rate to evaluate the postoperative effect by different decompression methods. Two hundred and thirty five patients were followed up with a mean period of 18 months (range, 4 to 36 months). JOA scores of all patients were improved by different degrees after operations. Anterior and posterior decompression methods both can achieve higher mean improvement rates. There were no significant differences in mean improvement rates between anterior groups, and so did male and female (P > 0.05). The effect will decrease as age increases or the course of disease prolongs. Statistical significance existed among the different age groups and between course groups (P < 0.05). Anterior and posterior decompression methods both can achieve good effect. The key point is to choose the surgical indication correctly, decompress thoroughly, and make the fusion reliable and fixation firm. In regard to the patients' imageological evaluation, the methods should be

  20. Decompression experiments identify kinetic controls on explosive silicic eruptions

    USGS Publications Warehouse

    Mangan, M.T.; Sisson, T.W.; Hankins, W.B.

    2004-01-01

    Eruption intensity is largely controlled by decompression-induced release of water-rich gas dissolved in magma. It is not simply the amount of gas that dictates how forcefully magma is propelled upwards during an eruption, but also the rate of degassing, which is partly a function of the supersaturation pressure (??Pcritical) triggering gas bubble nucleation. High temperature and pressure decompression experiments using rhyolite and dacite melt reveal compositionally-dependent differences in the ??Pcritical of degassing that may explain why rhyolites have fueled some of the most explosive eruptions on record.

  1. Endothelial cell culture in microfluidic devices for investigating microvascular processes.

    PubMed

    Mannino, Robert G; Qiu, Yongzhi; Lam, Wilbur A

    2018-07-01

    Numerous conditions and disease states such as sickle cell disease, malaria, thrombotic microangiopathy, and stroke significantly impact the microvasculature function and its role in disease progression. Understanding the role of cellular interactions and microvascular hemodynamic forces in the context of disease is crucial to understanding disease pathophysiology. In vivo models of microvascular disease using animal models often coupled with intravital microscopy have long been utilized to investigate microvascular phenomena. However, these methods suffer from some major drawbacks, including the inability to tightly and quantitatively control experimental conditions, the difficulty of imaging multiple microvascular beds within a living organism, and the inability to isolate specific microvascular geometries such as bifurcations. Thus, there exists a need for in vitro microvascular models that can mitigate the drawbacks associated with in vivo systems. To that end, microfluidics has been widely used to develop such models, as it allows for tight control of system inputs, facile imaging, and the ability to develop robust and repeatable systems with well-defined geometries. Incorporating endothelial cells to branching microfluidic models allows for the development of "endothelialized" systems that accurately recapitulate physiological microvessels. In this review, we summarize the field of endothelialized microfluidics, specifically focusing on fabrication methods, limitations, and applications of these systems. We then speculate on future directions and applications of these cutting edge technologies. We believe that this review of the field is of importance to vascular biologists and bioengineers who aim to utilize microfluidic technologies to solve vascular problems.

  2. Eruptive dynamics during magma decompression: a laboratory approach

    NASA Astrophysics Data System (ADS)

    Spina, L.; Cimarelli, C.; Scheu, B.; Wadsworth, F.; Dingwell, D. B.

    2013-12-01

    A variety of eruptive styles characterizes the activity of a given volcano. Indeed, eruptive styles can range from effusive phenomena to explosive eruptions, with related implications for hazard management. Rapid changes in eruptive style can occur during an ongoing eruption. These changes are, amongst other, related to variations in the magma ascent rate, a key parameter affecting the eruptive style. Ascent rate is in turn dependent on several factors such as the pressure in the magma chamber, the physical properties of the magma and the rate at which these properties change. According to the high number of involved parameters, laboratory decompression experiments are the best way to achieve quantitative information on the interplay of each of those factors and the related impact on the eruption style, i.e. by analyzing the flow and deformation behavior of the transparent volatile-bearing analogue fluid. We carried out decompression experiments following different decompression paths and using silicone oil as an analogue for the melt, with which we can simulate a range of melt viscosity values. For a set of experiments we added rigid particles to simulate the presence of crystals in the magma. The pure liquid or suspension was mounted into a transparent autoclave and pressurized to different final pressures. Then the sample was saturated with argon for a fixed amount of time. The decompression path consists of a slow decompression from the initial pressure to the atmospheric condition. Alternatively, samples were decompressed almost instantaneously, after established steps of slow decompression. The decompression path was monitored with pressure transducers and a high-speed video camera. Image analysis of the videos gives quantitative information on the bubble distribution with respect to depth in the liquid, pressure and time of nucleation and on their characteristics and behavior during the ongoing magma ascent. Furthermore, we also monitored the evolution of

  3. Original endoscopic orbital decompression of lateral wall through hairline approach for Graves' ophthalmopathy: an innovation of balanced orbital decompression.

    PubMed

    Gong, Yi; Yin, Jiayang; Tong, Boding; Li, Jingkun; Zeng, Jiexi; Zuo, Zhongkun; Ye, Fei; Luo, Yongheng; Xiao, Jing; Xiong, Wei

    2018-01-01

    Orbital decompression is an important surgical procedure for treatment of Graves' ophthalmopathy (GO), especially in women. It is reasonable for balanced orbital decompression of the lateral and medial wall. Various surgical approaches, including endoscopic transnasal surgery for medial wall and eye-side skin incision surgery for lateral wall, are being used nowadays, but many of them lack the validity, safety, or cosmetic effect. Endoscopic orbital decompression of lateral wall through hairline approach and decompression of medial wall via endoscopic transnasal surgery was done to achieve a balanced orbital decompression, aiming to improve the appearance of proptosis and create conditions for possible strabismus and eyelid surgery afterward. From January 29, 2016 to February 14, 2017, this surgery was performed on 41 orbits in 38 patients with GO, all of which were at inactive stage of disease. Just before surgery and at least 3 months after surgery, Hertel's ophthalmostatometer and computed tomography (CT) were used to check proptosis and questionnaires of GO quality of life (QOL) were completed. The postoperative retroversion of eyeball was 4.18±1.11 mm (Hertel's ophthalmostatometer) and 4.17±1.14 mm (CT method). The patients' QOL was significantly improved, especially the change in appearance without facial scar. The only postoperative complication was local soft tissue depression at temporal region. Obvious depression occurred in four cases (9.76%), which can be repaired by autologous fat filling. This surgery is effective, safe, and cosmetic. Effective balanced orbital decompression can be achieved by using this original and innovative surgery method. The whole manipulation is safe and controllable under endoscope. The postoperative scar of endoscopic surgery through hairline approach is covered by hair and the anatomic structure of anterior orbit is not impacted.

  4. 46 CFR Appendix A to Part 197 - Air No-Decompression Limits

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Air No-Decompression Limits A Appendix A to Part 197... STANDARDS GENERAL PROVISIONS Pt. 197, App. A Appendix A to Part 197—Air No-Decompression Limits The following table gives the depth versus bottom time limits for single, no-decompression, air dives made...

  5. 46 CFR Appendix A to Part 197 - Air No-Decompression Limits

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Air No-Decompression Limits A Appendix A to Part 197... STANDARDS GENERAL PROVISIONS Pt. 197, App. A Appendix A to Part 197—Air No-Decompression Limits The following table gives the depth versus bottom time limits for single, no-decompression, air dives made...

  6. 46 CFR Appendix A to Part 197 - Air No-Decompression Limits

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Air No-Decompression Limits A Appendix A to Part 197... STANDARDS GENERAL PROVISIONS Pt. 197, App. A Appendix A to Part 197—Air No-Decompression Limits The following table gives the depth versus bottom time limits for single, no-decompression, air dives made...

  7. 46 CFR Appendix A to Part 197 - Air No-Decompression Limits

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Air No-Decompression Limits A Appendix A to Part 197... STANDARDS GENERAL PROVISIONS Pt. 197, App. A Appendix A to Part 197—Air No-Decompression Limits The following table gives the depth versus bottom time limits for single, no-decompression, air dives made...

  8. Influence of Silicone Sheets on Microvascular Anastomosis

    PubMed Central

    Kloeppel, Marcus; Hoehnke, Christoph; Staudenmaier, Rainer

    2008-01-01

    The use of silicone products combined with free flap transfer is well established in reconstructive surgery. We determined the risk of thrombosis as a result of direct contact between the silicone sheet and the point of microanastomosis. We performed microvascular surgery in 24 female Chinchilla Bastard rabbits weighing 3500 to 4000 g using two groups: Group 1 (n = 12), microanastomosis directly in contact with silicone sheets; and Group 2 (n = 12), microanastomosis protected by a 2 × 3 × 1-cm muscle cuff before being placed in contact with the silicone. We assessed flow-through of the microanastomosis by selective microangiography and histology at 1 and 3 weeks. All microanastomoses in Group 1 were occluded by postoperative thromboses, whereas all microanastomoses in Group 2 had adequate flow-through. Histologic analysis revealed thromboses in Group 1 formed from collagenous bundles of fiber securely attached to the intraluminal wall of the vessel. Three weeks after the procedure, these thromboses were canalized by varying small vessels. In Group 2, a slight luminal stenosis with evidence of infiltration of inflammatory cells at the microanastomosis line was observed histologically in all cases. Prefabricated flaps using silicone sheets and muscular cuffs placed around the anastomoses appear to reduce the risk of thrombosis and enhance neovascularization. PMID:18636304

  9. Influence of silicone sheets on microvascular anastomosis.

    PubMed

    Hoang Nguyen, The; Kloeppel, Marcus; Hoehnke, Christoph; Staudenmaier, Rainer

    2008-12-01

    The use of silicone products combined with free flap transfer is well established in reconstructive surgery. We determined the risk of thrombosis as a result of direct contact between the silicone sheet and the point of microanastomosis. We performed microvascular surgery in 24 female Chinchilla Bastard rabbits weighing 3500 to 4000 g using two groups: Group 1 (n = 12), microanastomosis directly in contact with silicone sheets; and Group 2 (n = 12), microanastomosis protected by a 2 x 3 x 1-cm muscle cuff before being placed in contact with the silicone. We assessed flow-through of the microanastomosis by selective microangiography and histology at 1 and 3 weeks. All microanastomoses in Group 1 were occluded by postoperative thromboses, whereas all microanastomoses in Group 2 had adequate flow-through. Histologic analysis revealed thromboses in Group 1 formed from collagenous bundles of fiber securely attached to the intraluminal wall of the vessel. Three weeks after the procedure, these thromboses were canalized by varying small vessels. In Group 2, a slight luminal stenosis with evidence of infiltration of inflammatory cells at the microanastomosis line was observed histologically in all cases. Prefabricated flaps using silicone sheets and muscular cuffs placed around the anastomoses appear to reduce the risk of thrombosis and enhance neovascularization.

  10. Scalp reconstruction by microvascular free tissue transfer

    SciTech Connect

    Furnas, H.; Lineaweaver, W.C.; Alpert, B.S.

    1990-05-01

    We report on a series of patients with scalp defects who have been treated with a variety of free flaps, spanning the era of microvascular free tissue transfer from its incipient stages to the present. Between 1971 and 1987, 18 patients underwent scalp reconstruction with 21 free flaps: 11 latissimus dorsi, 3 scalp transfers between identical twins, 3 groin, one combined latissimus dorsi and serratus anterior, two serratus anterior, and one omentum. These flaps were used to cover scalp defects resulting from burns, trauma, radiation, and tumors in patients ranging from 7 to 79 years of age. Follow-up has rangedmore » from 3 weeks to 7 years. All of our flaps survived and covered complex defects, many of which had failed more conservative attempts at cover. One patient received radiation therapy to his flap without unfavorable sequelae. This experience began with a pioneering omental flap and includes cutaneous and muscle flaps. The latissimus dorsi is our first choice for free flap reconstruction of extensive, complicated scalp wounds because of its large size, predictable blood supply, ease of harvesting, and provision of excellent vascularity to compromised beds.« less

  11. Transnasal Endoscopic Optic Nerve Decompression in Post Traumatic Optic Neuropathy.

    PubMed

    Gupta, Devang; Gadodia, Monica

    2018-03-01

    To quantify the successful outcome in patients following optic nerve decompression in post traumatic unilateral optic neuropathy in form of improvement in visual acuity. A prospective study was carried out over a period of 5 years (January 2011 to June 2016) at civil hospital Ahmedabad. Total 20 patients were selected with optic neuropathy including patients with direct and indirect trauma to unilateral optic nerve, not responding to conservative management, leading to optic neuropathy and subsequent impairment in vision and blindness. Decompression was done via Transnasal-Ethmo-sphenoidal route and outcome was assessed in form of post-operative visual acuity improvement at 1 month, 6 months and 1 year follow up. After surgical decompression complete recovery of visual acuity was achieved in 16 (80%) patients and partial recovery in 4 (20%). Endoscopic transnasal approach is beneficial in traumatic optic neuropathy not responding to steroid therapy and can prevent permanent disability if earlier intervention is done prior to irreversible damage to the nerve. Endoscopic optic nerve surgery can decompress the traumatic and oedematous optic nerve with proper exposure of orbital apex and optic canal without any major intracranial, intraorbital and transnasal complications.

  12. Reduction rate by decompression as a treatment of odontogenic cysts.

    PubMed

    Oliveros-Lopez, L; Fernandez-Olavarria, A; Torres-Lagares, D; Serrera-Figallo, M-A; Castillo-Oyagüe, R; Segura-Egea, J-J; Gutierrez-Perez, J-L

    2017-09-01

    Odontogenic cysts are defined as those cysts that arise from odontogenic epithelium and occur in the tooth-bearing regions of the jaws. Cystectomy, marsupialization or decompression of odontogenic cyst are treatment approach to this pathology. The aim of this study was to evaluate the effectiveness of the decompression as the primary treatment of the cystic lesions of the jaws and them reduction rates involving different factors. 23 patients with odontogenic cysts of the jaws, previously diagnosed by anatomical histopathology (follicular cysts (7) and radicular cysts (16)) underwent decompression as an initial treatment. Clinical examination and pre and post panoramic radiograph were measured and analyzed. In addition, data as gender, age, time reduction and location of the lesion were collected. Significant results were obtained in relation to the location of lesions and the reduction rate (p<0.01). In a higher initial lesion, a greater reduction rate was observed (p<0.05). Decompression as an initial treatment of cystic lesions of the jaws was effective; it reduces the size of the lesions avoiding a possible damage to adjacent structures. Cystic lesions in the mandible, regardless of the area where they occur will have a higher reduction rate if it is compared with the maxilla. Similar behavior was identified in large lesions compared to smaller.

  13. Health care worker decompression sickness: incidence, risk and mitigation.

    PubMed

    Clarke, Richard

    2017-01-01

    Inadvertent exposure to radiation, chemical agents and biological factors are well recognized hazards associated with the health care delivery system. Less well appreciated yet no less harmful is risk of decompression sickness in those who accompany patients as inside attendants (IAs) during provision of hyperbaric oxygen therapy. Unlike the above hazards where avoidance is practiced, IA exposure to decompression sickness risk is unavoidable. While overall incidence is low, when calculated as number of cases over number of exposures or potential for a case during any given exposure, employee cumulative risk, defined here as number of cases over number of IAs, or risk that an IA may suffer a case, is not. Commonly, this unique occupational environmental injury responds favorably to therapeutic recompression and a period of recuperation. There are, however, permanent and career-ending consequences, and at least two nurses have succumbed to their decompression insults. The intent of this paper is to heighten awareness of hyperbaric attendant decompression sickness. It will serve as a review of reported cases and reconcile incidence against largely ignored individual worker risk. Mitigation strategies are summarized and an approach to more precisely identify risk factors that might prompt development of consensus screening standards is proposed. Copyright© Undersea and Hyperbaric Medical Society.

  14. Endoscopic Endonasal Optic Nerve Decompression for Fibrous Dysplasia

    PubMed Central

    DeKlotz, Timothy R.; Stefko, S. Tonya; Fernandez-Miranda, Juan C.; Gardner, Paul A.; Snyderman, Carl H.; Wang, Eric W.

    2016-01-01

    Objective To evaluate visual outcomes and potential complications for optic nerve decompression using an endoscopic endonasal approach (EEA) for fibrous dysplasia. Design Retrospective chart review of patients with fibrous dysplasia causing extrinsic compression of the canalicular segment of the optic nerve that underwent an endoscopic endonasal optic nerve decompression at the University of Pittsburgh Medical Center from 2010 to 2013. Main Outcome Measures The primary outcome measure assessed was best-corrected visual acuity (BCVA) with secondary outcomes, including visual field testing, color vision, and complications associated with the intervention. Results A total of four patients and five optic nerves were decompressed via an EEA. All patients were symptomatic preoperatively and had objective findings compatible with compressive optic neuropathy: decreased visual acuity was noted preoperatively in three patients while the remaining patient demonstrated an afferent pupillary defect. BCVA improved in all patients postoperatively. No major complications were identified. Conclusion EEA for optic nerve decompression appears to be a safe and effective treatment for patients with compressive optic neuropathy secondary to fibrous dysplasia. Further studies are required to identify selection criteria for an open versus an endoscopic approach. PMID:28180039

  15. A Log Logistic Survival Model Applied to Hypobaric Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny

    2001-01-01

    Decompression sickness (DCS) is a complex, multivariable problem. A mathematical description or model of the likelihood of DCS requires a large amount of quality research data, ideas on how to define a decompression dose using physical and physiological variables, and an appropriate analytical approach. It also requires a high-performance computer with specialized software. I have used published DCS data to develop my decompression doses, which are variants of equilibrium expressions for evolved gas plus other explanatory variables. My analytical approach is survival analysis, where the time of DCS occurrence is modeled. My conclusions can be applied to simple hypobaric decompressions - ascents lasting from 5 to 30 minutes - and, after minutes to hours, to denitrogenation (prebreathing). They are also applicable to long or short exposures, and can be used whether the sufferer of DCS is at rest or exercising at altitude. Ultimately I would like my models to be applied to astronauts to reduce the risk of DCS during spacewalks, as well as to future spaceflight crews on the Moon and Mars.

  16. Decompression-Driven Superconductivity Enhancement in In2 Se3.

    PubMed

    Ke, Feng; Dong, Haini; Chen, Yabin; Zhang, Jianbo; Liu, Cailong; Zhang, Junkai; Gan, Yuan; Han, Yonghao; Chen, Zhiqiang; Gao, Chunxiao; Wen, Jinsheng; Yang, Wenge; Chen, Xiao-Jia; Struzhkin, Viktor V; Mao, Ho-Kwang; Chen, Bin

    2017-09-01

    An unexpected superconductivity enhancement is reported in decompressed In 2 Se 3 . The onset of superconductivity in In 2 Se 3 occurs at 41.3 GPa with a critical temperature (T c ) of 3.7 K, peaking at 47.1 GPa. The striking observation shows that this layered chalcogenide remains superconducting in decompression down to 10.7 GPa. More surprisingly, the highest T c that occurs at lower decompression pressures is 8.2 K, a twofold increase in the same crystal structure as in compression. It is found that the evolution of T c is driven by the pressure-induced R-3m to I-43d structural transition and significant softening of phonons and gentle variation of carrier concentration combined in the pressure quench. The novel decompression-induced superconductivity enhancement implies that it is possible to maintain pressure-induced superconductivity at lower or even ambient pressures with better superconducting performance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Arthroscopic-assisted core decompression of the humeral head.

    PubMed

    Dines, Joshua S; Strauss, Eric J; Fealy, Stephen; Craig, Edward V

    2007-01-01

    Humeral head osteonecrosis is a progressive disease that requires prompt diagnosis and treatment. Core decompression is a viable treatment option for early-stage cases. Most surgeons perform core decompression by arthroscopically visualizing the necrotic area of bone and using a cannulated drill to take a core. Several attempts are frequently needed to reach the proper location. In the hip multiple passes are associated with complications. We describe the use of an anterior cruciate ligament (ACL) tibial drill guide to precisely localize the area of necrotic bone. Diagnostic arthroscopy is performed to assess the areas of osteonecrosis. Core decompression is performed by use of an ACL tibial guide, brought in through the anterior or posterior portal to precisely localize the necrotic area in preparation for drilling. Under image intensification, Steinmann pins are advanced into the area of osteonecrosis. Once positioned, several 4-mm cores are made. We treated 3 patients with this technique, and all had immediate pain relief. The use of the ACL guide allows precise localization of the area of humeral head involvement and avoids multiple drillings into unaffected areas. Initial indications are that arthroscopic-assisted core decompression with an ACL guide is an effective alternative to previously used methods.

  18. 21 CFR 884.5225 - Abdominal decompression chamber.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Abdominal decompression chamber. 884.5225 Section 884.5225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic...

  19. 21 CFR 884.5225 - Abdominal decompression chamber.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Abdominal decompression chamber. 884.5225 Section 884.5225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic...

  20. 21 CFR 884.5225 - Abdominal decompression chamber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Abdominal decompression chamber. 884.5225 Section 884.5225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic...

  1. 21 CFR 884.5225 - Abdominal decompression chamber.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Abdominal decompression chamber. 884.5225 Section 884.5225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic...

  2. Decompressive craniectomy and hydrocephalus: proposal of a therapeutic flow chart.

    PubMed

    Peraio, Simone; Calcagni, Maria Lucia; Mattoli, Maria Vittoria; Marziali, Giammaria; DE Bonis, Pasquale; Pompucci, Angelo; Anile, Carmelo; Mangiola, Annunziato

    2017-12-01

    Decompressive craniectomy (DC) may be necessary to save the lives of patients suffering from intracranial hypertension. However, this procedure is not complication-free. Its two main complications are hydrocephalus and the sinking skin-flap syndrome (SSFS). The radiological findings and the clinical evaluation may be not enough to decide when and/or how to treat hydrocephalus in a decompressed patient. SSFS and hydrocephalus may be not unrelated. In fact, a patient affected by hydrocephalus, after the ventriculo-peritoneal shunt, can develop SSFS; on the other hand, SSFS per se can cause hydrocephalus. Treating hydrocephalus in decompressed patients can be challenging. Radiological findings and clinical evaluation may not be enough to define the most appropriate therapeutic strategy. Cerebrospinal fluid (CSF) dynamics and metabolic evaluations can represent important diagnostic tools for assessing the need of a CSF shunt in patients with a poor baseline neurologic status. Based on our experience, we propose a flow chart for treating decompressed patients affected by ventriculomegaly.

  3. 21 CFR 884.5225 - Abdominal decompression chamber.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Abdominal decompression chamber. 884.5225 Section 884.5225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... abdominal pain during pregnancy or labor. (b) Classification. Class III (premarket approval). (c) Date PMA...

  4. Biomechanical analysis of the upper thoracic spine after decompressive procedures.

    PubMed

    Healy, Andrew T; Lubelski, Daniel; Mageswaran, Prasath; Bhowmick, Deb A; Bartsch, Adam J; Benzel, Edward C; Mroz, Thomas E

    2014-06-01

    Decompressive procedures such as laminectomy, facetectomy, and costotransversectomy are routinely performed for various pathologies in the thoracic spine. The thoracic spine is unique, in part, because of the sternocostovertebral articulations that provide additional strength to the region relative to the cervical and lumbar spines. During decompressive surgeries, stability is compromised at a presently unknown point. To evaluate thoracic spinal stability after common surgical decompressive procedures in thoracic spines with intact sternocostovertebral articulations. Biomechanical cadaveric study. Fresh-frozen human cadaveric spine specimens with intact rib cages, C7-L1 (n=9), were used. An industrial robot tested all spines in axial rotation (AR), lateral bending (LB), and flexion-extension (FE) by applying pure moments (±5 Nm). The specimens were first tested in their intact state and then tested after each of the following sequential surgical decompressive procedures at T4-T5 consisting of laminectomy; unilateral facetectomy; unilateral costotransversectomy, and subsequently instrumented fusion from T3-T7. We found that in all three planes of motion, the sequential decompressive procedures caused no statistically significant change in motion between T3-T7 or T1-T12 when compared with intact. In comparing between intact and instrumented specimens, our study found that instrumentation reduced global range of motion (ROM) between T1-T12 by 16.3% (p=.001), 12% (p=.002), and 18.4% (p=.0004) for AR, FE, and LB, respectively. Age showed a negative correlation with motion in FE (r = -0.78, p=.01) and AR (r=-0.7, p=.04). Thoracic spine stability was not significantly affected by sequential decompressive procedures in thoracic segments at the level of the true ribs in all three planes of motion in intact thoracic specimens. Age appeared to negatively correlate with ROM of the specimen. Our study suggests that thoracic spinal stability is maintained immediately after

  5. Reversible Microvascular Hyporeactivity to Acetylcholine During Diabetic Ketoacidosis.

    PubMed

    Joffre, Jérémie; Bourcier, Simon; Hariri, Geoffroy; Miailhe, Arnaud-Felix; Bigé, Naike; Dumas, Guillaume; Dubée, Vincent; Boelle, Pierre-Yves; Abdallah, Idriss; Baudel, Jean-Luc; Guidet, Bertrand; Maury, Eric; Ait-Oufella, Hafid

    2018-05-18

    Metabolic acidosis is commonly observed in critically ill patients. Experimental studies suggested that acidosis by itself could impair vascular function, but this has been poorly investigated in human. Prospective observational study. Medical ICU in a tertiary teaching hospital. To assess the relationship between metabolic acidosis severity and microvascular reactivity, we included adult diabetic patients admitted in ICU for ketoacidosis. Microvascular response to acetylcholine iontophoresis was measured at admission (baseline) and after correction of metabolic acidosis (24 hr). None. Thirty-nine patients with diabetic ketoacidosis were included (68% male), with a median age of 43 (31-57) years. At admission, microvascular reactivity negatively correlated with acidosis severity (R = -0.53; p < 0.001). Microvascular response was strongly depressed at pH less than 7.20 (area under the curve, 1,779 [740-3,079] vs 12,944 [4,874-21,596] at pH > 7.20; p < 0.0001). In addition, acidosis severity was significantly correlated with capillary refill time (R = 0.50; p = 0.02). At H24, after rehydration and insulin infusion, clinical and biological disorders were fully corrected. After acidosis correction, microvascular reactivity increased more in patients with severe baseline acidosis (pH < 7.20) than in those with mild baseline acidosis (area under the curve, +453% [213%-1,470%] vs +121% [79%-312%]; p < 0.01). We identified an alteration of microvascular reactivity during metabolic acidosis in critically ill patients with diabetic ketoacidosis. Microvascular hyporeactivity recovered after acidosis correction.

  6. Comparison of clinical outcomes in decompression and fusion versus decompression only in patients with ossification of the posterior longitudinal ligament: a meta-analysis.

    PubMed

    Mehdi, Syed K; Alentado, Vincent J; Lee, Bryan S; Mroz, Thomas E; Benzel, Edward C; Steinmetz, Michael P

    2016-06-01

    OBJECTIVE Ossification of the posterior longitudinal ligament (OPLL) is a pathological calcification or ossification of the PLL, predominantly occurring in the cervical spine. Although surgery is often necessary for patients with symptomatic neurological deterioration, there remains controversy with regard to the optimal surgical treatment. In this systematic review and meta-analysis, the authors identified differences in complications and outcomes after anterior or posterior decompression and fusion versus after decompression alone for the treatment of cervical myelopathy due to OPLL. METHODS A MEDLINE, SCOPUS, and Web of Science search was performed for studies reporting complications and outcomes after decompression and fusion or after decompression alone for patients with OPLL. A meta-analysis was performed to calculate effect summary mean values, 95% CIs, Q statistics, and I(2) values. Forest plots were constructed for each analysis group. RESULTS Of the 2630 retrieved articles, 32 met the inclusion criteria. There was no statistically significant difference in the incidence of excellent and good outcomes and of fair and poor outcomes between the decompression and fusion and the decompression-only cohorts. However, the decompression and fusion cohort had a statistically significantly higher recovery rate (63.2% vs 53.9%; p < 0.0001), a higher final Japanese Orthopaedic Association score (14.0 vs 13.5; p < 0.0001), and a lower incidence of OPLL progression (< 1% vs 6.3%; p < 0.0001) compared with the decompression-only cohort. There was no statistically significant difference in the incidence of complications between the 2 cohorts. CONCLUSIONS This study represents the only comprehensive review of outcomes and complications after decompression and fusion or after decompression alone for OPLL across a heterogeneous group of surgeons and patients. Based on these results, decompression and fusion is a superior surgical technique compared with posterior

  7. Cell-microenvironment interactions and architectures in microvascular systems

    PubMed Central

    Bersini, Simone; Yazdi, Iman K.; Talò, Giuseppe; Shin, Su Ryon; Moretti, Matteo; Khademhosseini, Ali

    2016-01-01

    In the past decade, significant advances have been made in the design and optimization of novel biomaterials and microfabrication techniques to generate vascularized tissues. Novel microfluidic systems have facilitated the development and optimization of in vitro models for exploring the complex pathophysiological phenomena that occur inside a microvascular environment. To date, most of these models have focused on engineering of increasingly complex systems, rather than analyzing the molecular and cellular mechanisms that drive microvascular network morphogenesis and remodeling. In fact, mutual interactions among endothelial cells (ECs), supporting mural cells and organ-specific cells, as well as between ECs and the extracellular matrix, are key driving forces for vascularization. This review focuses on the integration of materials science, microengineering and vascular biology for the development of in vitro microvascular systems. Various approaches currently being applied to study cell-cell/cell-matrix interactions, as well as biochemical/biophysical cues promoting vascularization and their impact on microvascular network formation, will be identified and discussed. Finally, this review will explore in vitro applications of microvascular systems, in vivo integration of transplanted vascularized tissues, and the important challenges for vascularization and controlling the microcirculatory system within the engineered tissues, especially for microfabrication approaches. It is likely that existing models and more complex models will further our understanding of the key elements of vascular network growth, stabilization and remodeling to translate basic research principles into functional, vascularized tissue constructs for regenerative medicine applications, drug screening and disease models. PMID:27417066

  8. Cell-microenvironment interactions and architectures in microvascular systems.

    PubMed

    Bersini, Simone; Yazdi, Iman K; Talò, Giuseppe; Shin, Su Ryon; Moretti, Matteo; Khademhosseini, Ali

    2016-11-01

    In the past decade, significant advances have been made in the design and optimization of novel biomaterials and microfabrication techniques to generate vascularized tissues. Novel microfluidic systems have facilitated the development and optimization of in vitro models for exploring the complex pathophysiological phenomena that occur inside a microvascular environment. To date, most of these models have focused on engineering of increasingly complex systems, rather than analyzing the molecular and cellular mechanisms that drive microvascular network morphogenesis and remodeling. In fact, mutual interactions among endothelial cells (ECs), supporting mural cells and organ-specific cells, as well as between ECs and the extracellular matrix, are key driving forces for vascularization. This review focuses on the integration of materials science, microengineering and vascular biology for the development of in vitro microvascular systems. Various approaches currently being applied to study cell-cell/cell-matrix interactions, as well as biochemical/biophysical cues promoting vascularization and their impact on microvascular network formation, will be identified and discussed. Finally, this review will explore in vitro applications of microvascular systems, in vivo integration of transplanted vascularized tissues, and the important challenges for vascularization and controlling the microcirculatory system within the engineered tissues, especially for microfabrication approaches. It is likely that existing models and more complex models will further our understanding of the key elements of vascular network growth, stabilization and remodeling to translate basic research principles into functional, vascularized tissue constructs for regenerative medicine applications, drug screening and disease models. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. MACULAR MICROVASCULAR NETWORKS IN HEALTHY PEDIATRIC SUBJECTS.

    PubMed

    Borrelli, Enrico; Lonngi, Marcela; Balasubramanian, Siva; Tepelus, Tudor C; Baghdasaryan, Elmira; Iafe, Nicholas A; Pineles, Stacy L; Velez, Federico G; Sarraf, David; Sadda, SriniVas R; Tsui, Irena

    2018-02-22

    To report optical coherence tomography angiography (OCTA) values in healthy pediatric eyes and to identify factors that may modify these values. In this prospective observational cross-sectional study, macular OCTA images were acquired from healthy pediatric patients. Main outcome measures were 1) foveal avascular zone (FAZ) area at the level of the superficial retinal capillary plexus (SCP); 2) SCP and deep retinal capillary plexus (DCP) perfusion density (based on the area of vessels); 3) SCP and DCP vessel density (based on a map with vessels of 1-pixel width); and 4) CC perfusion density. Multiple regression analysis was performed to assess the effect of age, sex, ethnicity, refraction, and foveal macular thickness (FMT) on OCTA parameters. Seventy-seven eyes from 52 subjects (23 male and 29 female) were included in analysis. Mean age was 11.1 ± 3.3 years (range = 5.0-17.0 years). Twenty-nine (55.8%) subjects were white, 14 (27.0%) Hispanic, 8 (15.4%) Asian, and 1 (1.8%) African-American. Mean refraction was -0.1 ± 2.4 diopters (D) (range = -5.75 to +9.0 D). Mean FMT was 248.6 ± 18.6 μm. Larger FAZ area was significantly associated with older age (P = 0.014). Furthermore, larger FAZ area was associated with reduced FMT (P < 0.0001). Male sex was associated only with increased SCP perfusion density (P = 0.042). Increased CC perfusion density was associated with younger age (P = 0.022). We report data for pediatric OCTA parameters in healthy subjects. Several variables influence the density of macular microvascular networks, and these factors should be considered in the OCTA study of pediatric eye disorders.

  10. Brain microvascular function during cardiopulmonary bypass

    SciTech Connect

    Sorensen, H.R.; Husum, B.; Waaben, J.

    1987-11-01

    Emboli in the brain microvasculature may inhibit brain activity during cardiopulmonary bypass. Such hypothetical blockade, if confirmed, may be responsible for the reduction of cerebral metabolic rate for glucose observed in animals subjected to cardiopulmonary bypass. In previous studies of cerebral blood flow during bypass, brain microcirculation was not evaluated. In the present study in animals (pigs), reduction of the number of perfused capillaries was estimated by measurements of the capillary diffusion capacity for hydrophilic tracers of low permeability. Capillary diffusion capacity, cerebral blood flow, and cerebral metabolic rate for glucose were measured simultaneously by the integral method, different tracersmore » being used with different circulation times. In eight animals subjected to normothermic cardiopulmonary bypass, and seven subjected to hypothermic bypass, cerebral blood flow, cerebral metabolic rate for glucose, and capillary diffusion capacity decreased significantly: cerebral blood flow from 63 to 43 ml/100 gm/min in normothermia and to 34 ml/100 gm/min in hypothermia and cerebral metabolic rate for glucose from 43.0 to 23.0 mumol/100 gm/min in normothermia and to 14.1 mumol/100 gm/min in hypothermia. The capillary diffusion capacity declined markedly from 0.15 to 0.03 ml/100 gm/min in normothermia but only to 0.08 ml/100 gm/min in hypothermia. We conclude that the decrease of cerebral metabolic rate for glucose during normothermic cardiopulmonary bypass is caused by interruption of blood flow through a part of the capillary bed, possibly by microemboli, and that cerebral blood flow is an inadequate indicator of capillary blood flow. Further studies must clarify why normal microvascular function appears to be preserved during hypothermic cardiopulmonary bypass.« less

  11. Angiotensin II-mediated microvascular thrombosis

    PubMed Central

    Senchenkova, Elena Y.; Russell, Janice; Almeida-Paula, Lidiana D.; Harding, Joseph W.; Granger, D. Neil

    2010-01-01

    Hypertension is associated with an increased risk of thrombosis that appears to involve an interaction between the renin-angiotensin system and hemostasis. In this study we determined whether angiotensin II-mediatedthrombosis occurs in arterioles and/or venules, and assessed the involvement of type-1 (AT1), type-2 (AT2) and type 4 (AT4) angiotensin II receptors, as well as receptors for endothelin-1 (ET-1) and bradykinin (BK-1, BK-2) in angiotensin II-enhanced microvascular thrombosis. Thrombus development in mouse cremaster microvessels was quantified after light/dye injury using the time of onset of the thrombus and time to blood flow cessation. Wild type and AT1-receptor deficient mice were implanted with an angiotensin II-loaded Alzet pump for 2 wks. Angiotensin II administration in both wild type and AT1-receptor deficient mice significantly accelerated thrombosis in arterioles. Genetic deficiency and pharmacological antagonism of AT1-receptors did not alter the thrombosis response to angiotensin II. Isolated murine platelets aggregated in response to low (pM), but not high (nM), concentrations of angiotensin II. The platelet aggregation response to angiotensin II was dependent on AT1-receptors. Antagonism of AT2-receptors in vivo significantly prolonged the onset of angiotensin II enhanced thrombosis, while an AT4-receptor antagonist prolonged the time to flow cessation. Selective antagonism of either ET-1 or BK-1 receptors largely prevented both the onset and flow cessation responses to chronic angiotensin II infusion. Our findings indicate that angiotensin II-induced hypertension is accompanied by enhanced thrombosis in arterioles and this response is mediated by a mechanism that involves AT2, AT4, BK-1 and ET-1 receptor-mediated signaling. PMID:20975035

  12. Risk of decompression sickness in the presence of circulating microbubbles

    NASA Technical Reports Server (NTRS)

    Kumar, K. Vasantha; Powell, Michael R.

    1993-01-01

    In this study, we examined the association between microbubbles formed in the circulation from a free gas phase and symptoms of altitude decompression sickness (DCS). In a subgroup of 59 males of mean (S.D) age 31.2 (5.8) years who developed microbubbles during exposure to 26.59 kPa (4.3 psi) under simulated extravehicular activities (EVA), symptoms of DCS occurred in 24 (41 percent) individuals. Spencer grade 1 microbubbles occurred in 4 (7 percent), grade 2 in 9 (15 percent), grade 3 in 15 (25 percent), and grade 4 in 31 (53 percent) of subjects. Survival analysis using Cox proportional hazards regression showed that individuals with less than grade 3 CMB showed 2.46 times (95 percent confidence interval = 1.26 to 5.34) higher risk of symptoms. This information is crucial for defining the risk of DCS for inflight Doppler monitoring under space EVA. Altitude decompression sickness (DCS) occurs when there is acute reduction in ambient pressure. The symptoms of DCS are due to the formation of a free gas phase (in the form of gas microbubbles) in tissues during decompression. Musculo-skeletal pain of bends is the commonest form of DCS in altitude exposures. In the space flight environment, there is a risk of DCS when astronauts decompress from the normobaric shuttle pressure into the hypobaric space suit pressure (currently about 29.65 kPa (4.3 psi) for extra-vehicular activities (EVA). This risk is counterbalanced by a judicious combination of prior denitrogenation and staged decompression. Studies of DCS are limited by the duration of the test at reduced pressure. Since only a proportion of subjects tested develop symptoms, the information on DCS is generally incomplete or 'censored'. Many studies employ Doppler ultrasound monitoring of the precordial area for detecting circulating microbubbles (CMB). Although the association between CMB and bends pain is not causal, CMB are frequently monitored during decompression. In this paper, we examine the association

  13. Regional cutaneous microvascular flow responses during gravitational and LBNP stresses

    NASA Technical Reports Server (NTRS)

    Breit, Gregory A.; Watenpaugh, Donald E.; Ballard, Richard E.; Murthy, Gita; Hargens, Alan R.

    1993-01-01

    Due to the regional variability of local hydrostatic pressures, microvascular flow responses to gravitational stress probably vary along the length of the body. Although these differences in local autoregulation have been observed previously during whole-body tilting, they have not been investigated during application of artificial gravitational stresses, such as lower body negative pressure or high gravity centrifugation. Although these stresses can create equivalent G-levels at the feet, they result in distinct distributions of vascular transmural pressure along the length of the body, and should consequently elicit different magnitudes and distributions of microvascular response. In the present study, the effects of whole-body tilting and lower body negative pressure on the level and distribution of microvascular flows within skin along the length of the body were compared.

  14. Active cooling of microvascular composites for battery packaging

    NASA Astrophysics Data System (ADS)

    Pety, Stephen J.; Chia, Patrick X. L.; Carrington, Stephen M.; White, Scott R.

    2017-10-01

    Batteries in electric vehicles (EVs) require a packaging system that provides both thermal regulation and crash protection. A novel packaging scheme is presented that uses active cooling of microvascular carbon fiber reinforced composites to accomplish this multifunctional objective. Microvascular carbon fiber/epoxy composite panels were fabricated and their cooling performance assessed over a range of thermal loads and experimental conditions. Tests were performed for different values of coolant flow rate, channel spacing, panel thermal conductivity, and applied heat flux. More efficient cooling occurs when the coolant flow rate is increased, channel spacing is reduced, and thermal conductivity of the host composite is increased. Computational fluid dynamics (CFD) simulations were also performed and correlate well with the experimental data. CFD simulations of a typical EV battery pack confirm that microvascular composite panels can adequately cool battery cells generating 500 W m-2 heat flux below 40 °C.

  15. Gap filling of 3-D microvascular networks by tensor voting.

    PubMed

    Risser, L; Plouraboue, F; Descombes, X

    2008-05-01

    We present a new algorithm which merges discontinuities in 3-D images of tubular structures presenting undesirable gaps. The application of the proposed method is mainly associated to large 3-D images of microvascular networks. In order to recover the real network topology, we need to fill the gaps between the closest discontinuous vessels. The algorithm presented in this paper aims at achieving this goal. This algorithm is based on the skeletonization of the segmented network followed by a tensor voting method. It permits to merge the most common kinds of discontinuities found in microvascular networks. It is robust, easy to use, and relatively fast. The microvascular network images were obtained using synchrotron tomography imaging at the European Synchrotron Radiation Facility. These images exhibit samples of intracortical networks. Representative results are illustrated.

  16. Microvascular endothelial function and severity of primary open angle glaucoma.

    PubMed

    Bukhari, S M I; Kiu, K Y; Thambiraja, R; Sulong, S; Rasool, A H G; Liza-Sharmini, A T

    2016-12-01

    PurposeThe role of microvascular endothelial dysfunction on severity of primary open angle glaucoma (POAG) was investigated in this study.Patients and methodsA prospective cohort study was conducted. One hundred and fourteen ethnically Malay patients (114 eyes) with POAG treated at the eye clinic of Hospital University Sains Malaysia between April 2012 and December 2014 were recruited. Patients aged between 40 and 80 years with two consecutive reliable and reproducible Humphrey visual field 24-2 analyses were selected. Patients who were diagnosed with any other type of glaucoma, previous glaucoma-filtering surgery, or other surgeries except uncomplicated cataract and pterygium surgery were excluded. Humphrey visual field analysis 24-2 was used to stratify the severity of glaucoma using Advanced Glaucoma Intervention Study (AGIS) score at the time of recruitment. Microvascular endothelial function was assessed using Laser Doppler fluximetry and iontophoresis. Iontophoresis process with acetylcholine (ACh) and sodium nitroprusside (SNP) was used to measure microvascular endothelium-dependent and -independent vasodilatation, respectively.ResultsBased on the AGIS score, 55 patients showed mild glaucoma, with 29 moderate and 30 severe. There was statistically significant difference in microvascular endothelial function (ACh% and ACh max ) between mild and moderate POAG cases (P=0.023) and between mild and severe POAG cases (P<0.001). There was negative correlation between microvascular endothelial function and severity of POAG (r=-0.457, P<0.001).ConclusionMicrovascular endothelial dysfunction may have a role in influencing the severity of POAG in Malay patients.

  17. Retinal Microvascular Network and Microcirculation Assessments in High Myopia.

    PubMed

    Li, Min; Yang, Ye; Jiang, Hong; Gregori, Giovanni; Roisman, Luiz; Zheng, Fang; Ke, Bilian; Qu, Dongyi; Wang, Jianhua

    2017-02-01

    To investigate the changes of the retinal microvascular network and microcirculation in high myopia. A cross-sectional, matched, comparative clinical study. Twenty eyes of 20 subjects with nonpathological high myopia (28 ± 5 years of age) with a refractive error of -6.31 ± 1.23 D (mean ± SD) and 20 eyes of 20 age- and sex-matched control subjects (30 ± 6 years of age) with a refractive error of -1.40 ± 1.00 D were recruited. Optical coherence tomography angiography (OCTA) was used to image the retinal microvascular network, which was later quantified by fractal analysis (box counting [D box ], representing vessel density) in both superficial and deep vascular plexuses. The Retinal Function Imager was used to image the retinal microvessel blood flow velocity (BFV). The BFV and microvascular density in the myopia group were corrected for ocular magnification using Bennett's formula. The density of both superficial and deep microvascular plexuses was significantly decreased in the myopia group in comparison to the controls (P < .05). The decrease of the microvessel density of the annular zone (0.6-2.5 mm), measured as D box , was 2.1% and 2.9% in the superficial and deep vascular plexuses, respectively. Microvessel density reached a plateau from 0.5 mm to 1.25 mm from the fovea in both groups, but that in the myopic group was about 3% lower than the control group. No significant differences were detected between the groups in retinal microvascular BFV in either arterioles or venules (P > .05). Microvascular densities in both superficial (r = -0.45, P = .047) and deep (r = -0.54, P = .01) vascular plexuses were negatively correlated with the axial lengths in the myopic eye. No correlations were observed between BFV and vessel density (P > .05). Retinal microvascular decrease was observed in the high myopia subjects, whereas the retinal microvessel BFV remained unchanged. The retinal microvascular network alteration may be attributed to ocular

  18. Coronary microvascular dysfunction equivalent to left main coronary artery disease.

    PubMed

    Panç, Cafer; Kocaağa, Mehmet; Erdoğan, Onur; Sarıkaya, Remzi; Umman, Sabahattin

    2017-04-01

    Coronary microvascular dysfunction, also known as cardiac syndrome X, is a clinical syndrome presenting with typical angina and evidence of myocardial ischemia in the absence of flow-limiting stenosis on coronary angiography. Of patients undergoing coronary angiography due to suspected myocardial ischemia, 50% are found to have normal or near-normal coronary arteries. Described in this case report is a patient who developed hypotension and ST segment depressions during treadmill exercise test. Left main coronary artery or multivessel disease was suspected. Coronary angiography was normal, but coronary flow reserve measurement revealed severe microvascular dysfunction.

  19. Engineering Microvascularized 3D Tissue Using Alginate-Chitosan Microcapsules.

    PubMed

    Zhang, Wujie; Choi, Jung K; He, Xiaoming

    2017-02-01

    Construction of vascularized tissues is one of the major challenges of tissue engineering. The goal of this study was to engineer 3D microvascular tissues by incorporating the HUVEC-CS cells with a collagen/alginate-chitosan (AC) microcapsule scaffold. In the presence of AC microcapsules, a 3D vascular-like network was clearly observable. The results indicated the importance of AC microcapsules in engineering microvascular tissues -- providing support and guiding alignment of HUVEC-CS cells. This approach provides an alternative and promising method for constructing vascularized tissues.

  20. Prevention of decompression sickness during a simulated space docking mission

    NASA Technical Reports Server (NTRS)

    Cooke, J. P.; Bollinger, R. R.; Richardson, B.

    1975-01-01

    This study has shown that repetitive exchanges between the Apollo space vehicle atmosphere of 100% oxygen at 5 psia (258 torr) and the Soyuz spacecraft atmosphere of 30% oxygen-70% nitrogen at 10 psia (533 torr), as simulated in altitude chambers, will not likely result in any form of decompression sickness. This conclusion is based upon the absence of any form of bends in seven crewmen who participated in 11 tests distributed over three 24-h periods. During each period, three transfers from the 5 to the 10 psia environments were performed by simulating passage through a docking module which served as an airlock where astronauts and cosmonauts first adapted to each other's cabin gases and pressures before transfer. Biochemical tests, subjective fatigue scores, and the complete absence of any form of pain were also indicative that decompression sickness should not be expected if this spacecraft transfer schedule is followed.

  1. [Decompressive craniectomy in the management of sylvian infarction].

    PubMed

    Berhouma, Moncef; Khouja, Néjib; Jemel, Hafedh; Khaldi, Moncef

    2006-09-01

    Space-occupying middle cerebral artery infarction represents about 10 to 15% of supratentorial ischemic strokes. This syndrome carries a high rate of mortality and requires aggressive surgical decompression. The authors present 6 patients with signs of trans-tentorial herniation operated on between February 2001 and August 2003. Neurological preoperative status was evaluated with Glasgow coma scale score and postoperatively with Barthel index. Three patients had excellent recovery (Barthel Index up to 70), one remained dependant and two died. Younger patients had better prognosis. Decompressive surgery, when done early, should improve mortality rate and even functional outcome. Optimal selection of patients, with the help of Diffusion-Weighted imaging, could vouch good results.

  2. Report on computation of repetitive hyperbaric-hypobaric decompression tables

    NASA Technical Reports Server (NTRS)

    Edel, P. O.

    1975-01-01

    The tables were constructed specifically for NASA's simulated weightlessness training program; they provide for 8 depth ranges covering depths from 7 to 47 FSW, with exposure times of 15 to 360 minutes. These tables were based up on an 8 compartment model using tissue half-time values of 5 to 360 minutes and Workmanline M-values for control of the decompression obligation resulting from hyperbaric exposures. Supersaturation ratios of 1.55:1 to 2:1 were used for control of ascents to altitude following such repetitive dives. Adequacy of the method and the resultant tables were determined in light of past experience with decompression involving hyperbaric-hypobaric interfaces in human exposures. Using these criteria, the method showed conformity with empirically determined values. In areas where a discrepancy existed, the tables would err in the direction of safety.

  3. A case of decompression sickness in a commercial pilot.

    PubMed

    Wolf, C W; Petzl, D H; Seidl, G; Burghuber, O C

    1989-10-01

    We report a case of decompression sickness (DCS) followed by pulmonary edema in a 47-year-old commercial pilot who operated a non-pressurized turboprop twin at flight level 290. He became unconscious and recovered after an emergency descent. The pilot collapsed and a pulmonary edema occurred 8 h after landing. The patient improved rapidly with fluid replacement and without hyperbaric therapy, which was not available at that time. This course of DCS is unusual because it is reported that fluid replacement without hyperbaric therapy normally cannot recover severe cases of DCS. The considerable increase in body weight of this pilot within the last 6 months may have been a predisposing factor for development of decompression sickness.

  4. [Orbital decompression in Grave's disease: comparison of techniques].

    PubMed

    Sellari-Franceschini, S; Berrettini, S; Forli, F; Bartalena, L; Marcocci, C; Tanda, M L; Nardi, M; Lepri, A; Pinchera, A

    1999-12-01

    Grave's ophthalmopathy is an inflammatory, autoimmune disorder often associated with Grave's disease. The inflammatory infiltration involves the retrobulbar fatty tissue and the extrinsic eye muscles, causing proptosis, extraocular muscle dysfunction and often diplopia. Orbital decompression is an effective treatment in such cases, particularly when resistant to drugs and external radiation therapy. This work compares the results of orbital decompression performed by removing: a) the medial and lateral walls (Mourits technique) in 10 patients (19 orbits) and b) the medial and lower walls (Walsh-Ogura technique) in 17 patients (31 orbits). The results show that removing the floor of the orbit enables better reduction of proptosis but more easily leads to post-operative diplopia. Thus it proves necessary to combine the two techniques, modifying the surgical approach on a case-by-case basis.

  5. Predictive modeling of altitude decompression sickness in humans

    NASA Technical Reports Server (NTRS)

    Kenyon, D. J.; Hamilton, R. W., Jr.; Colley, I. A.; Schreiner, H. R.

    1972-01-01

    The coding of data on 2,565 individual human altitude chamber tests is reported as part of a selection procedure designed to eliminate individuals who are highly susceptible to decompression sickness, individual aircrew members were exposed to the pressure equivalent of 37,000 feet and observed for one hour. Many entries refer to subjects who have been tested two or three times. This data contains a substantial body of statistical information important to the understanding of the mechanisms of altitude decompression sickness and for the computation of improved high altitude operating procedures. Appropriate computer formats and encoding procedures were developed and all 2,565 entries have been converted to these formats and stored on magnetic tape. A gas loading file was produced.

  6. A rare remote epidural hematoma secondary to decompressive craniectomy.

    PubMed

    Xu, Gang-Zhu; Wang, Mao-De; Liu, Kai-Ge; Bai, Yin-An

    2014-01-01

    Remote epidural hematoma (REDH) is an uncommon complication of decompressive craniectomy. Remote epidural hematomas of the parietal occiput region have been reported only rarely. We report a unique case of delayed-onset bilateral extensive straddle postsagittal sinus and bilateral lateral sinus parietal occiput REDH after decompressive craniectomy, of which volume was approximately 130 mL, with left deviating midline structures. The patient was immediately taken back to the operating room for evacuation of the REDH via bilateral parietal and occiput craniectomy. Postoperatively, serial computed tomographic scans performed 3 days later showed that the REDH had been completely evacuated. Two months later, the patient regained full consciousness and obtained a near-complete recovery except for right facial paralysis.

  7. Spinal decompression sickness: mechanical studies and a model.

    PubMed

    Hills, B A; James, P B

    1982-09-01

    Six experimental investigations of various mechanical aspects of the spinal cord are described relevant to its injury by gas deposited from solution by decompression. These show appreciable resistances to gas pockets dissipating by tracking along tissue boundaries or distending tissue, the back pressure often exceeding the probable blood perfusion pressure--particularly in the watershed zones. This leads to a simple mechanical model of spinal decompression sickness based on the vascular "waterfall" that is consistent with the pathology, the major quantitative aspects, and the symptomatology--especially the reversibility with recompression that is so difficult to explain by an embolic mechanism. The hypothesis is that autochthonous gas separating from solution in the spinal cord can reach sufficient local pressure to exceed the perfusion pressure and thus occlude blood flow.

  8. Timing of cranioplasty after decompressive craniectomy for trauma.

    PubMed

    Piedra, Mark P; Nemecek, Andrew N; Ragel, Brian T

    2014-01-01

    The optimal timing of cranioplasty after decompressive craniectomy for trauma is unknown. The aim of this study was to determine if early cranioplasty after decompressive craniectomy for trauma reduces complications. Consecutive cases of patients who underwent autologous cranioplasty after decompressive craniectomy for trauma at a single Level I Trauma Center were studied in a retrospective 10 year data review. Associations of categorical variables were compared using Chi-square test or Fisher's exact test. A total of 157 patients were divided into early (<12 weeks; 78 patients) and late (≥12 weeks; 79 patients) cranioplasty cohorts. Baseline characteristics were similar between the two cohorts. Cranioplasty operative time was significantly shorter in the early (102 minutes) than the late (125 minutes) cranioplasty cohort (P = 0.0482). Overall complication rate in both cohorts was 35%. Infection rates were lower in the early (7.7%) than the late (14%) cranioplasty cohort as was bone graft resorption (15% early, 19% late), hydrocephalus rate (7.7% early, 1.3% late), and postoperative hematoma incidence (3.9% early, 1.3% late). However, these differences were not statistically significant. Patients <18 years of age were at higher risk of bone graft resorption than patients ≥18 years of age (OR 3.32, 95% CI 1.25-8.81; P = 0.0162). After decompressive craniectomy for trauma, early (<12 weeks) cranioplasty does not alter the incidence of complication rates. In patients <18 years of age, early (<12 weeks) cranioplasty increases the risk of bone resorption. Delaying cranioplasty (≥12 weeks) results in longer operative times and may increase costs.

  9. Operation Everest II. Altitude Decompression Sickness during Repeated Altitude Exposure,

    DTIC Science & Technology

    1986-05-01

    Bends, Altitude, Hypobaric Chamber ILrJ " . .. . . " --" . .. " * .- . - - ’,, 3 INTRODUCTION Altitude Decompression Sickness (ADS) is a well...recognized and serious consequence of exposure to hypobaric conditions. It has been described during and after aircraft as well as hypobaric chamber flights...was noted in investigators during a recent study of chronic progressive hypoxia in a hypobaric chamber entitled Operation Everest II. The observations

  10. The Possible Relationship Between Patent Foramen Ovale and Decompression Sickness:.

    DTIC Science & Technology

    1999-01-01

    a potential conduit for blood clot (resulting in a stroke), or venous gas bubbles during decompression, (resulting in type II neurologic...Despite the high prevalence of PFO in the general population, and the relatively common occurrence of venous gas bubbles in diving and altitude exposures...being present in up to a third of the population. The potential for right- to-left shunting of venous gas emboli (VGE) which are known to occur in even

  11. Optimal timing of autologous cranioplasty after decompressive craniectomy in children.

    PubMed

    Piedra, Mark P; Thompson, Eric M; Selden, Nathan R; Ragel, Brian T; Guillaume, Daniel J

    2012-10-01

    The object of this study was to determine if early cranioplasty after decompressive craniectomy for elevated intracranial pressure in children reduces complications. Sixty-one consecutive cases involving pediatric patients who underwent autologous cranioplasty after decompressive craniectomy for raised intracranial pressure at a single academic children's hospital over 15 years were studied retrospectively. Sixty-one patients were divided into early (< 6 weeks; 28 patients) and late (≥ 6 weeks; 33 patients) cranioplasty cohorts. The cohorts were similar except for slightly lower age in the early (8.03 years) than the late (10.8 years) cranioplasty cohort (p < 0.05). Bone resorption after cranioplasty was significantly more common in the late (42%) than the early (14%) cranioplasty cohort (p < 0.05; OR 5.4). No other complication differed in incidence between the cohorts. After decompressive craniectomy for raised intracranial pressure in children, early (< 6 weeks) cranioplasty reduces the occurrence of reoperation for bone resorption, without altering the incidence of other complications.

  12. Rapid versus gradual bladder decompression in acute urinary retention.

    PubMed

    Etafy, Mohamed H; Saleh, Fatma H; Ortiz-Vanderdys, Cervando; Hamada, Alaa; Refaat, Alaa M; Aal, Mohamed Abdel; Deif, Hazem; Gawish, Maher; Abdellatif, Ashraf H; Gadalla, Khaled

    2017-01-01

    To demonstrate a benefit in diminished adverse events such as hypotension and hematuria with gradual drainage of the bladder when compared to rapid decompression in patients with acute urinary retention (AUR) due to benign prostatic hyperplasia in a case-control study. Sixty-two patients matched our selection criteria presenting with AUR. They were divided into two groups - the first was managed by rapid drainage of the bladder, the second was managed by gradual drainage through a urethral catheter (The first 100 mL immediately evacuated, then the rest evacuated gradually over 2 h). The mean age was 64.4 and 63.2 years in the first and second group, respectively. Diagnosed cause was benign hyperplasia of the prostate. Hematuria occurred in two patients in the first group and none in the second group. The two cases of hematuria were mild and treated conservatively. After the relief of the obstruction, the mean blood pressure was noticed to decrease by 15 mmHg and 10 mmHg in the first and second group, respectively, however, no one developed significant hypotension. Pain relief was achieved after complete drainage in the first group and after the evacuation of 100 mL in the second group. We conclude that there is no significant difference between rapid and gradual decompression of the bladder in patients with AUR. Hematuria and hypotension may occur after rapid decompression of the obstructed urinary bladder, but these complications are rarely clinically significant.

  13. Strain on intervertebral discs after anterior cervical decompression and fusion.

    PubMed

    Matsunaga, S; Kabayama, S; Yamamoto, T; Yone, K; Sakou, T; Nakanishi, K

    1999-04-01

    An analysis of the change in strain distribution of intervertebral discs present after anterior cervical decompression and fusion by an original method. The analytical results were compared to occurrence of herniation of the intervertebral disc on magnetic resonance imaging. To elucidate the influence of anterior cervical decompression and fusion on the unfused segments of the spine. There is no consensus regarding the exact significance of the biomechanical change in the unfused segment present after surgery. Ninety-six patients subjected to anterior cervical decompression and fusion for herniation of intervertebral discs were examined. Shear strain and longitudinal strain of intervertebral discs were analyzed on pre- and postoperative lateral dynamic routine radiography of the cervical spine. Thirty of the 96 patients were examined by magnetic resonance imaging before and after surgery, and the relation between alteration in strains and postsurgical occurrence of disc herniation was examined. In the cases of double- or triple-level fusion, shear strain of adjacent segments had increased 20% on average 1 year after surgery. Thirteen intervertebral discs that had an abnormally high degree of strain showed an increase in longitudinal strain after surgery. Eleven (85%) of the 13 discs that showed an abnormal increase in longitudinal strain had herniation in the same intervertebral discs with compression of the spinal cord during the follow-up period. Relief of symptoms was significantly poor in the patients with recent herniation. Close attention should be paid to long-term biomechanical changes in the unfused segment.

  14. Microsurgical Decompression of Inferior Alveolar Nerve After Endodontic Treatment Complications.

    PubMed

    Bianchi, Bernardo; Ferri, Andrea; Varazzani, Andrea; Bergonzani, Michela; Sesenna, Enrico

    2017-07-01

    Iatrogenic injury in oral surgery is the most frequent cause of sensory disturbance in the distribution of the inferior alveolar nerve (IAN) and mental nerve.Inferior alveolar nerve damage can occur during third molar extraction, implant location, orthognathic surgery, preprosthetic surgery, salivary gland surgery, local anesthetic injections or during the resection of benign or malignant tumors.Injuries to the IAN can be caused also by endodontic treatment of mandibular molars and premolars when filling material is forced into the tooth and mandibular canal.The sensory disturbances that could follow a damage of the IAN could be hypoesthesia, dysesthesia, hyperesthesia, anesthesia, and sometimes a painful anesthesia that strike ipsilateral lower lip, chin, and teeth. These can undermine life quality by affecting speech, chewing, and social interaction.Treatment of these complications is sometimes difficult and could consist in observation or in surgical decompression of the involved nerve to relieve the patient's symptoms and improve sensory recovery. The most debated points are the timing of intervention and the effective role of decompression in clinical outcome-improvement.The purpose of this article is to show authors' experience with 2 patients treated with microsurgical nerve decompression to remove endodontic material from the mandibular canal and providing also a comprehensive review of the literature.

  15. White matter changes linked to visual recovery after nerve decompression

    PubMed Central

    Paul, David A.; Gaffin-Cahn, Elon; Hintz, Eric B.; Adeclat, Giscard J.; Zhu, Tong; Williams, Zoë R.; Vates, G. Edward; Mahon, Bradford Z.

    2015-01-01

    The relationship between the integrity of white matter tracts and cortical function in the human brain remains poorly understood. Here we use a model of reversible white matter injury, compression of the optic chiasm by tumors of the pituitary gland, to study the structural and functional changes that attend spontaneous recovery of cortical function and visual abilities after surgical tumor removal and subsequent decompression of the nerves. We show that compression of the optic chiasm leads to demyelination of the optic tracts, which reverses as quickly as 4 weeks after nerve decompression. Furthermore, variability across patients in the severity of demyelination in the optic tracts predicts visual ability and functional activity in early cortical visual areas, and pre-operative measurements of myelination in the optic tracts predicts the magnitude of visual recovery after surgery. These data indicate that rapid regeneration of myelin in the human brain is a significant component of the normalization of cortical activity, and ultimately the recovery of sensory and cognitive function, after nerve decompression. More generally, our findings demonstrate the utility of diffusion tensor imaging as an in vivo measure of myelination in the human brain. PMID:25504884

  16. Micro-surgical decompression for greater occipital neuralgia.

    PubMed

    Li, Fuyong; Ma, Yi; Zou, Jianjun; Li, Yanfeng; Wang, Bin; Huang, Haitao; Wang, Quancai; Li, Liang

    2012-01-01

    To evaluate the clinical effect of micro-surgical decompression of greater occipital nerve for greater occipital neuralgia (GON). 76 patients underwent surgical decompression of the great occipital nerve. A nerve block was tested before operation. The headache rapidly resolved after infiltration of 1% Lidocaine near the tender area of the nerve trunk. 89 procedures were performed for 76 patients. The mean follow up duration was 20 months (range 7-52 months). The headache symptoms of 68 (89.5%) patients were completely resolved, and another 5 (6.6%) patients were significantly relieved without the need for any further medical treatment. Three (3.9%) patients experienced recurrence of the disorder. All patients experienced hypoesthesia of the innervated area of the great occipital nerve. They recovered gradually within 1 to 6 months after surgery. Micro-surgical decompression of the greater occipital nerve is a safe and effective method for greater occipital neuralgia. We believe our findings support the notion that the technique should also be considered as the first-line procedure for GON.

  17. Decryption-decompression of AES protected ZIP files on GPUs

    NASA Astrophysics Data System (ADS)

    Duong, Tan Nhat; Pham, Phong Hong; Nguyen, Duc Huu; Nguyen, Thuy Thanh; Le, Hung Duc

    2011-10-01

    AES is a strong encryption system, so decryption-decompression of AES encrypted ZIP files requires very large computing power and techniques of reducing the password space. This makes implementations of techniques on common computing system not practical. In [1], we reduced the original very large password search space to a much smaller one which surely containing the correct password. Based on reduced set of passwords, in this paper, we parallel decryption, decompression and plain text recognition for encrypted ZIP files by using CUDA computing technology on graphics cards GeForce GTX295 of NVIDIA, to find out the correct password. The experimental results have shown that the speed of decrypting, decompressing, recognizing plain text and finding out the original password increases about from 45 to 180 times (depends on the number of GPUs) compared to sequential execution on the Intel Core 2 Quad Q8400 2.66 GHz. These results have demonstrated the potential applicability of GPUs in this cryptanalysis field.

  18. Do modern techniques improve core decompression outcomes for hip osteonecrosis?

    PubMed

    Marker, David R; Seyler, Thorsten M; Ulrich, Slif D; Srivastava, Siddharth; Mont, Michael A

    2008-05-01

    Core decompression procedures have been used in osteonecrosis of the femoral head to attempt to delay the joint destruction that may necessitate hip arthroplasty. The efficacy of core decompressions has been variable with many variations of technique described. To determine whether the efficacy of this procedure has improved during the last 15 years using modern techniques, we compared recently reported radiographic and clinical success rates to results of surgeries performed before 1992. Additionally, we evaluated the outcomes of our cohort of 52 patients (79 hips) who were treated with multiple small-diameter drillings. There was a decrease in the proportion of patients undergoing additional surgeries and an increase in radiographic success when comparing pre-1992 results to patients treated in the last 15 years. However, there were fewer Stage III hips in the more recent reports, suggesting that patient selection was an important reason for this improvement. The results of the small-diameter drilling cohort were similar to other recent reports. Patients who had small lesions and were Ficat Stage I had the best results with 79% showing no radiographic progression. Our study confirms core decompression is a safe and effective procedure for treating early stage femoral head osteonecrosis.

  19. Interspinous Process Decompression: Expanding Treatment Options for Lumbar Spinal Stenosis

    PubMed Central

    Nunley, Pierce D.; Shamie, A. Nick; Blumenthal, Scott L.; Orndorff, Douglas; Geisler, Fred H.

    2016-01-01

    Interspinous process decompression is a minimally invasive implantation procedure employing a stand-alone interspinous spacer that functions as an extension blocker to prevent compression of neural elements without direct surgical removal of tissue adjacent to the nerves. The Superion® spacer is the only FDA approved stand-alone device available in the US. It is also the only spacer approved by the CMS to be implanted in an ambulatory surgery center. We computed the within-group effect sizes from the Superion IDE trial and compared them to results extrapolated from two randomized trials of decompressive laminectomy. For the ODI, effect sizes were all very large (>1.0) for Superion and laminectomy at 2, 3, and 4 years. For ZCQ, the 2-year Superion symptom severity (1.26) and physical function (1.29) domains were very large; laminectomy effect sizes were very large (1.07) for symptom severity and large for physical function (0.80). Current projections indicate a marked increase in the number of patients with spinal stenosis. Consequently, there remains a keen interest in minimally invasive treatment options that delay or obviate the need for invasive surgical procedures, such as decompressive laminectomy or fusion. Stand-alone interspinous spacers may fill a currently unmet treatment gap in the continuum of care and help to reduce the burden of this chronic degenerative condition on the health care system. PMID:27819001

  20. Interspinous Process Decompression: Expanding Treatment Options for Lumbar Spinal Stenosis.

    PubMed

    Nunley, Pierce D; Shamie, A Nick; Blumenthal, Scott L; Orndorff, Douglas; Block, Jon E; Geisler, Fred H

    2016-01-01

    Interspinous process decompression is a minimally invasive implantation procedure employing a stand-alone interspinous spacer that functions as an extension blocker to prevent compression of neural elements without direct surgical removal of tissue adjacent to the nerves. The Superion® spacer is the only FDA approved stand-alone device available in the US. It is also the only spacer approved by the CMS to be implanted in an ambulatory surgery center. We computed the within-group effect sizes from the Superion IDE trial and compared them to results extrapolated from two randomized trials of decompressive laminectomy. For the ODI, effect sizes were all very large (>1.0) for Superion and laminectomy at 2, 3, and 4 years. For ZCQ, the 2-year Superion symptom severity (1.26) and physical function (1.29) domains were very large ; laminectomy effect sizes were very large (1.07) for symptom severity and large for physical function (0.80). Current projections indicate a marked increase in the number of patients with spinal stenosis. Consequently, there remains a keen interest in minimally invasive treatment options that delay or obviate the need for invasive surgical procedures, such as decompressive laminectomy or fusion. Stand-alone interspinous spacers may fill a currently unmet treatment gap in the continuum of care and help to reduce the burden of this chronic degenerative condition on the health care system.

  1. Farris-Tang retractor in optic nerve sheath decompression surgery.

    PubMed

    Spiegel, Jennifer A; Sokol, Jason A; Whittaker, Thomas J; Bernard, Benjamin; Farris, Bradley K

    2016-01-01

    Our purpose is to introduce the use of the Farris-Tang retractor in optic nerve sheath decompression surgery. The procedure of optic nerve sheath fenestration was reviewed at our tertiary care teaching hospital, including the use of the Farris-Tang retractor. Pseudotumor cerebri is a syndrome of increased intracranial pressure without a clear cause. Surgical treatment can be effective in cases in which medical therapy has failed and disc swelling with visual field loss progresses. Optic nerve sheath decompression surgery (ONDS) involves cutting slits or windows in the optic nerve sheath to allow cerebrospinal fluid to escape, reducing the pressure around the optic nerve. We introduce the Farris-Tang retractor, a retractor that allows for excellent visualization of the optic nerve sheath during this surgery, facilitating the fenestration of the sheath and visualization of the subsequent cerebrospinal fluid egress. Utilizing a medial conjunctival approach, the Farris-Tang retractor allows for easy retraction of the medial orbital tissue and reduces the incidence of orbital fat protrusion through Tenon's capsule. The Farris-Tang retractor allows safe, easy, and effective access to the optic nerve with good visualization in optic nerve sheath decompression surgery. This, in turn, allows for greater surgical efficiency and positive patient outcomes.

  2. Musculoskeletal-induced Nucleation in Altitude Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Pollock, N. W.; Natoli, M. J.; Conkin, J.; Wessel, J. H., III; Gernhardt, M. L.

    2014-01-01

    Musculoskeletal activity has the potential to both improve and compromise decompression safety. Exercise enhances inert gas elimination during oxygen breathing prior to decompression (prebreathe), but it may also promote bubble nuclei formation (nucleation), which can lead to gas phase separation and bubble growth and increase the risk of decompression sickness (DCS). The timing, pattern and intensity of musculoskeletal activity and the level of tissue supersaturation may be critical to the net effect. There are limited data available to evaluate cost-benefit relationships. Understanding the relationship is important to improve our understanding of the underlying mechanisms of nucleation in exercise prebreathe protocols and to quantify risk in gravity and microgravity environments. Data gathered during NASA's Prebreathe Reduction Program (PRP) studies combined oxygen prebreathe and exercise followed by low pressure (4.3 psi; altitude equivalent of 30,300 ft [9,235 m]) microgravity simulation to produce two protocols used by astronauts preparing for extravehicular activity. Both the Phase II/CEVIS (cycle ergometer vibration isolation system) and ISLE (in-suit light exercise) trials eliminated ambulation to more closely simulate the microgravity environment. The CEVIS results (35 male, 10 female) serve as control data for this NASA/Duke study to investigate the influence of ambulation exercise on bubble formation and the subsequent risk of DCS.

  3. Rapid versus gradual bladder decompression in acute urinary retention

    PubMed Central

    Etafy, Mohamed H.; Saleh, Fatma H.; Ortiz-Vanderdys, Cervando; Hamada, Alaa; Refaat, Alaa M.; Aal, Mohamed Abdel; Deif, Hazem; Gawish, Maher; Abdellatif, Ashraf H.; Gadalla, Khaled

    2017-01-01

    Objective: To demonstrate a benefit in diminished adverse events such as hypotension and hematuria with gradual drainage of the bladder when compared to rapid decompression in patients with acute urinary retention (AUR) due to benign prostatic hyperplasia in a case–control study. Methods: Sixty-two patients matched our selection criteria presenting with AUR. They were divided into two groups – the first was managed by rapid drainage of the bladder, the second was managed by gradual drainage through a urethral catheter (The first 100 mL immediately evacuated, then the rest evacuated gradually over 2 h). Results: The mean age was 64.4 and 63.2 years in the first and second group, respectively. Diagnosed cause was benign hyperplasia of the prostate. Hematuria occurred in two patients in the first group and none in the second group. The two cases of hematuria were mild and treated conservatively. After the relief of the obstruction, the mean blood pressure was noticed to decrease by 15 mmHg and 10 mmHg in the first and second group, respectively, however, no one developed significant hypotension. Pain relief was achieved after complete drainage in the first group and after the evacuation of 100 mL in the second group. Conclusions: We conclude that there is no significant difference between rapid and gradual decompression of the bladder in patients with AUR. Hematuria and hypotension may occur after rapid decompression of the obstructed urinary bladder, but these complications are rarely clinically significant. PMID:29118535

  4. Trigeminal neuralgia caused by an anomalous posterior inferior cerebellar artery from the primitive trigeminal artery: case report.

    PubMed

    Lee, Seung Hwan; Koh, Jun Seok; Lee, Cheol Young

    2011-06-01

    A 61-year-old woman presented with typical trigeminal neuralgia (TN), caused by an aberrant posterior inferior cerebellar artery (PICA) associated with the primitive trigeminal artery (PTA). Magnetic resonance angiography and digital subtraction angiography clearly showed an anomalous artery directly originating from the PTA and coursing into the PICA territory at the cerebellum. During microvascular decompression (MVD), we confirmed and decompressed vascular compression of the trigeminal nerve by this anomalous, PICA-variant type of PTA. The PTA did not conflict with the trigeminal nerve, and the anomalous PICA only compressed the caudolateral part of the trigeminal nerve, without the more common compression at its root entry zone. This case is informative due not only to its very unusual angioanatomical variation but also to its helpfulness for surgeons preparing a MVD for a TN associated with such a rare vascular anomaly.

  5. Estimation of Blood Flow Rates in Large Microvascular Networks

    PubMed Central

    Fry, Brendan C.; Lee, Jack; Smith, Nicolas P.; Secomb, Timothy W.

    2012-01-01

    Objective Recent methods for imaging microvascular structures provide geometrical data on networks containing thousands of segments. Prediction of functional properties, such as solute transport, requires information on blood flow rates also, but experimental measurement of many individual flows is difficult. Here, a method is presented for estimating flow rates in a microvascular network based on incomplete information on the flows in the boundary segments that feed and drain the network. Methods With incomplete boundary data, the equations governing blood flow form an underdetermined linear system. An algorithm was developed that uses independent information about the distribution of wall shear stresses and pressures in microvessels to resolve this indeterminacy, by minimizing the deviation of pressures and wall shear stresses from target values. Results The algorithm was tested using previously obtained experimental flow data from four microvascular networks in the rat mesentery. With two or three prescribed boundary conditions, predicted flows showed relatively small errors in most segments and fewer than 10% incorrect flow directions on average. Conclusions The proposed method can be used to estimate flow rates in microvascular networks, based on incomplete boundary data and provides a basis for deducing functional properties of microvessel networks. PMID:22506980

  6. Intraoperative Computed Tomography for Cervicomedullary Decompression of Foramen Magnum Stenosis in Achondroplasia: Two Case Reports

    PubMed Central

    Arishima, Hidetaka; Tsunetoshi, Kenzo; Kodera, Toshiaki; Kitai, Ryuhei; Takeuchi, Hiroaki; Kikuta, Ken-ichiro

    2013-01-01

    The authors report two cases of cervicomedullary decompression of foramen magnum (FM) stenosis in children with achondroplasia using intraoperative computed tomography (iCT). A 14-month-old girl with myelopathy and retarded motor development, and a 10-year-old girl who had already undergone incomplete FM decompression was presented with myelopathy. Both patients underwent decompressive sub-occipitalcraniectomy and C1 laminectomy without duraplasty using iCT. It clearly showed the extent of FM decompression during surgery, which finally enabled sufficient decompression. After the operation, their myelopathy improved. We think that iCT can provide useful information and guidance for sufficient decompression for FM stenosis in children with achondroplasia. PMID:24140778

  7. Intraoperative computed tomography for cervicomedullary decompression of foramen magnum stenosis in achondroplasia: two case reports.

    PubMed

    Arishima, Hidetaka; Tsunetoshi, Kenzo; Kodera, Toshiaki; Kitai, Ryuhei; Takeuchi, Hiroaki; Kikuta, Ken-Ichiro

    2013-01-01

    The authors report two cases of cervicomedullary decompression of foramen magnum (FM) stenosis in children with achondroplasia using intraoperative computed tomography (iCT). A 14-month-old girl with myelopathy and retarded motor development, and a 10-year-old girl who had already undergone incomplete FM decompression was presented with myelopathy. Both patients underwent decompressive sub-occipitalcraniectomy and C1 laminectomy without duraplasty using iCT. It clearly showed the extent of FM decompression during surgery, which finally enabled sufficient decompression. After the operation, their myelopathy improved. We think that iCT can provide useful information and guidance for sufficient decompression for FM stenosis in children with achondroplasia.

  8. Influence of long-term intermittent exposures to hypoxia on decompression-induced pulmonary haemorrhage.

    PubMed Central

    Fang, H S; Chen, C F

    1976-01-01

    Healthy male rats were acclimatized by being placed in a decompression chamber at a simulated altitude of 18 000 feet (5486 m) for three hours daily for 84 days. The altitude acclimatized rats paired with unacclimatized rats were rapidly decompressed together. The range of decompression was performed from on atmospheric pressure to an ambient pressure of 30 mmHg in 0-2 seconds. It was found that in control rats, 14 of 20 lung (70%) exhibited pulmonary haemorrhage following rapid decompression. In altitude acclimatized rats, however, only 6 of 20 (30%) revealed decompression-induced haemorrhage. The difference was statistically significant. The present findings indicate that long-term intermittent exposures to hypoxia might increase the resistance of pulmonary tissue to rapid decompression, resulting in a decrease in frequency and severity of pulmonary haemorrhage. The possible mechanism of such a phenomenon is discussed. PMID:1257942

  9. Choroid Sprouting Assay: An Ex Vivo Model of Microvascular Angiogenesis

    PubMed Central

    Shao, Zhuo; Friedlander, Mollie; Hurst, Christian G.; Cui, Zhenghao; Pei, Dorothy T.; Evans, Lucy P.; Juan, Aimee M.; Tahir, Houda; Duhamel, François; Chen, Jing; Sapieha, Przemyslaw; Chemtob, Sylvain; Joyal, Jean-Sébastien; Smith, Lois E. H.

    2013-01-01

    Angiogenesis of the microvasculature is central to the etiology of many diseases including proliferative retinopathy, age-related macular degeneration and cancer. A mouse model of microvascular angiogenesis would be very valuable and enable access to a wide range of genetically manipulated tissues that closely approximate small blood vessel growth in vivo. Vascular endothelial cells cultured in vitro are widely used, however, isolating pure vascular murine endothelial cells is technically challenging. A microvascular mouse explant model that is robust, quantitative and can be reproduced without difficulty would overcome these limitations. Here we characterized and optimized for reproducibility an organotypic microvascular angiogenesis mouse and rat model from the choroid, a microvascular bed in the posterior of eye. The choroidal tissues from C57BL/6J and 129S6/SvEvTac mice and Sprague Dawley rats were isolated and incubated in Matrigel. Vascular sprouting was comparable between choroid samples obtained from different animals of the same genetic background. The sprouting area, normalized to controls, was highly reproducible between independent experiments. We developed a semi-automated macro in ImageJ software to allow for more efficient quantification of sprouting area. Isolated choroid explants responded to manipulation of the external environment while maintaining the local interactions of endothelial cells with neighboring cells, including pericytes and macrophages as evidenced by immunohistochemistry and fluorescence-activated cell sorting (FACS) analysis. This reproducible ex vivo angiogenesis assay can be used to evaluate angiogenic potential of pharmacologic compounds on microvessels and can take advantage of genetically manipulated mouse tissue for microvascular disease research. PMID:23922736

  10. Verocytotoxin-induced apoptosis of human microvascular endothelial cells.

    PubMed

    Pijpers, A H; van Setten, P A; van den Heuvel, L P; Assmann, K J; Dijkman, H B; Pennings, A H; Monnens, L A; van Hinsbergh, V W

    2001-04-01

    The pathogenesis of the epidemic form of hemolytic uremic syndrome is characterized by endothelial cell damage. In this study, the role of apoptosis in verocytotoxin (VT)-mediated endothelial cell death in human glomerular microvascular endothelial cells (GMVEC), human umbilical vein endothelial cells, and foreskin microvascular endothelial cells (FMVEC) was investigated. VT induced apoptosis in GMVEC and human umbilical vein endothelial cells when the cells were prestimulated with the inflammatory mediator tumor necrosis factor-alpha (TNF-alpha). FMVEC displayed strong binding of VT and high susceptibility to VT under basal conditions, which made them suitable for the study of VT-induced apoptosis without TNF-alpha interference. On the basis of functional (flow cytometry and immunofluorescence microscopy using FITC-conjugated annexin V and propidium iodide), morphologic (transmission electron microscopy), and molecular (agarose gel electrophoresis of cellular DNA fragments) criteria, it was documented that VT induced programmed cell death in microvascular endothelial cells in a dose- and time-dependent manner. Furthermore, whereas partial inhibition of protein synthesis by VT was associated with a considerable number of apoptotic cells, comparable inhibition of protein synthesis by cycloheximide was not. This suggests that additional pathways, independent of protein synthesis inhibition, may be involved in VT-mediated apoptosis in microvascular endothelial cells. Specific inhibition of caspases by Ac-Asp-Glu-Val-Asp-CHO, but not by Ac-Tyr-Val-Ala-Asp-CHO, was accompanied by inhibition of VT-induced apoptosis in FMVEC and TNF-alpha-treated GMVEC. These data indicate that VT can induce apoptosis in human microvascular endothelial cells.

  11. Potential Protective Mechanism in the Cardiac Microvascular Injury.

    PubMed

    Li, Xiuchuan; Hou, Juanni; Du, Jin; Feng, Jian; Yang, Yi; Shen, Yang; Chen, Sha; Feng, Juan; Yang, Dachun; Li, De; Pei, Haifeng; Yang, Yongjian

    2018-05-07

    Cardiac microvascular injury often occurs in patients with type 2 diabetes mellitus (T2DM) who develop hyperglycemia and hyperlipidemia. However, besides reported contradictory roles in cardiac diseases, the function of TRPV1 (transient receptor potential vanilloid 1) in cardiac microvessels is not well defined. This study was performed to determine the detailed role of TRPV1 in cardiac microvascular endothelial cells (CMECs) in T2DM. T2DM mice were established by multiple injections of low-dose streptozotocin and high-fat feeding. CMECs were cultured separately in mediums of normal glucose, high glucose (HG), high fatty acid (HF), and HG plus HF (HG-HF). HG-HF inhibited TRPV1 expression in CMECs, reducing cellular Ca 2+ content ([Ca 2+ ] i ). T2DM impaired cardiac function, disturbed glucose uptake, and damaged microvascular barrier, which were further aggravated by TRPV1 -/- Exposure to HG-HF, particularly in TRPV1 -/- CMECs, led to a higher level of apoptosis and a lower level of nitric oxide production in viable CMECs. HG-HF markedly enhanced generation of reactive oxygen species and nitrotyrosine, especially in the absence of TRPV1. H 2 O 2 administration reduced TRPV1 expression in CMECs. HG-HF significantly depressed expression of PGC-1α (peroxisome proliferator-activated receptor-γ coactivator-1α) and OPA1 (optic atrophy 1) by reducing [Ca 2+ ] i , whereas OPA1 supplementation partly reversed those detrimental effects induced by TRPV1 -/- Furthermore, capsaicin treatment not only attenuated CMECs injury induced by HG-HF but also mitigated cardiac microvascular injury induced by T2DM. Collectively, T2DM leads to cardiac microvascular injury by exacerbating the vicious circle of TRPV1 blockage and reactive oxygen species overload. Long-term capsaicin can protect cardiac microvessels against T2DM via suppressing oxidative/nitrative stress mediated by TRPV1/Ca 2+ /PGC-1α/OPA1 pathway in CMECs. © 2018 American Heart Association, Inc.

  12. Needle Decompression of Tension Pneumothorax Tactical Combat Casualty Care Guideline Recommendations

    DTIC Science & Technology

    2012-07-06

    SUBJECT: Needle Decompression of Tension Pneumothorax Tactical Combat Casualty Care Guideline Recommendations 2012-05 2 demonstrating the...Decompression of Tension Pneumothorax Tactical Combat Casualty Care Guideline Recommendations 2012-05 3 needle may be too short to reliably reach the...at the AAL as the preferred site for needle decompression of a presumed tension pneumothorax . Further, studies evaluating chest wall thickness are

  13. Effect of Inert Gas Switching at Depth on Decompression Outcome in Rats

    DTIC Science & Technology

    1989-01-01

    Indcuae Security Classification) Effect Of inert gas switching at depth on decompression outcome in rats Liil RVRcCall1urn M~E 16. SUPPLEMENTARY...CLASSIrICATrIONOF TI PAGE All other edition% -ate obsfee UNCLASSIFIED Effect of inert gas switching at depth on decompression outcome in rats R. S... Effect of inert gas Although various models of inert gas transport in the switching at depth on decompression outcome in rats. J. Appl

  14. Levodopa in Treatment of Decompression Sickness and of Air Embolism Induced Paraplegia in Rats.

    DTIC Science & Technology

    1981-08-28

    nitrosoureas (BCNU, CCNU) made additional progress in the treatment of brain tumors. A lipid soluble agent , 1,3-bis (2-Chloroethyl)-l- Nitrosourea (BCNU...mechanisms of levodopa and some other agents in the prevention and in the recovery of rats from decompression sickness. For better clarity the...brain occurring in decompression sickness. B. Decompression Sickness Studies. We have shown that gelatin, an agent that protects platelets during freezing

  15. Evaluation of safety of hypobaric decompressions and EVA from positions of probabilistic theory

    NASA Astrophysics Data System (ADS)

    Nikolaev, V. P.

    Formation and subsequent evolution of gas bubbles in blood and tissues of subjects exposed to decompression are casual processes in their nature. Such character of bubbling processes in a body predetermines probabilistic character of decompression sickness (DCS) incidence in divers, aviators and astronauts. Our original probabilistic theory of decompression safety is based on stochastic models of these processes and on the concept of critical volume of a free gas phase in body tissues. From positions of this theory, the probability of DCS incidence during single-stage decompressions and during hypobaric decompressions under EVA in particular, is defined by the distribution of possible values of nucleation efficiency in "pain" tissues and by its critical significance depended on the parameters of a concrete decompression. In the present study the following is shown: 1) the dimensionless index of critical nucleation efficiency for "pain" body tissues is a more adequate index of decompression stress in comparison with Tissue Ratio, TR; 2) a priory the decompression under EVA performed according to the Russian protocol is more safe than decompression under EVA performed in accordance with the U.S. protocol; 3) the Russian space suit operated at a higher pressure and having a higher "rigidity" induces a stronger inhibition of mechanisms of cavitation and gas bubbles formation in tissues of a subject located in it, and by that provides a more considerable reduction of the DCS risk during real EVA performance.

  16. Frequency of decompression illness among recent and extinct mammals and "reptiles": a review

    NASA Astrophysics Data System (ADS)

    Carlsen, Agnete Weinreich

    2017-08-01

    The frequency of decompression illness was high among the extinct marine "reptiles" and very low among the marine mammals. Signs of decompression illness are still found among turtles but whales and seals are unaffected. In humans, the risk of decompression illness is five times increased in individuals with Patent Foramen Ovale; this condition allows blood shunting from the venous circuit to the systemic circuit. This right-left shunt is characteristic of the "reptile" heart, and it is suggested that this could contribute to the high frequency of decompression illness in the extinct reptiles.

  17. Trends in Orbital Decompression Techniques of Surveyed American Society of Ophthalmic Plastic and Reconstructive Surgery Members.

    PubMed

    Reich, Shani S; Null, Robert C; Timoney, Peter J; Sokol, Jason A

    To assess current members of the American Society of Ophthalmic Plastic and Reconstructive Surgery (ASOPRS) regarding preference in surgical techniques for orbital decompression in Graves' disease. A 10-question web-based, anonymous survey was distributed to oculoplastic surgeons utilizing the ASOPRS listserv. The questions addressed the number of years of experience performing orbital decompression surgery, preferred surgical techniques, and whether orbital decompression was performed in collaboration with an ENT surgeon. Ninety ASOPRS members participated in the study. Most that completed the survey have performed orbital decompression surgery for >15 years. The majority of responders preferred a combined approach of floor and medial wall decompression or balanced lateral and medial wall decompression; only a minority selected a technique limited to 1 wall. Those surgeons who perform fat decompression were more likely to operate in collaboration with ENT. Most surgeons rarely remove the orbital strut, citing risk of worsening diplopia or orbital dystopia except in cases of optic nerve compression or severe proptosis. The most common reason given for performing orbital decompression was exposure keratopathy. The majority of surgeons perform the surgery without ENT involvement, and number of years of experience did not correlate significantly with collaboration with ENT. The majority of surveyed ASOPRS surgeons prefer a combined wall approach over single wall approach to initial orbital decompression. Despite the technological advances made in the field of modern endoscopic surgery, no single approach has been adopted by the ASOPRS community as the gold standard.

  18. Frequency of decompression illness among recent and extinct mammals and "reptiles": a review.

    PubMed

    Carlsen, Agnete Weinreich

    2017-08-01

    The frequency of decompression illness was high among the extinct marine "reptiles" and very low among the marine mammals. Signs of decompression illness are still found among turtles but whales and seals are unaffected. In humans, the risk of decompression illness is five times increased in individuals with Patent Foramen Ovale; this condition allows blood shunting from the venous circuit to the systemic circuit. This right-left shunt is characteristic of the "reptile" heart, and it is suggested that this could contribute to the high frequency of decompression illness in the extinct reptiles.

  19. Decompression Surgery Alone Versus Decompression Plus Fusion in Symptomatic Lumbar Spinal Stenosis: A Swiss Prospective Multicenter Cohort Study With 3 Years of Follow-up.

    PubMed

    Ulrich, Nils H; Burgstaller, Jakob M; Pichierri, Giuseppe; Wertli, Maria M; Farshad, Mazda; Porchet, François; Steurer, Johann; Held, Ulrike

    2017-09-15

    Retrospective analysis of a prospective, multicenter cohort study. To estimate the added effect of surgical fusion as compared to decompression surgery alone in symptomatic lumbar spinal stenosis patients with spondylolisthesis. The optimal surgical management of lumbar spinal stenosis patients with spondylolisthesis remains controversial. Patients of the Lumbar Stenosis Outcome Study with confirmed DLSS and spondylolisthesis were enrolled in this study. The outcomes of this study were Spinal Stenosis Measure (SSM) symptoms (score range 1-5, best-worst) and function (1-4) over time, measured at baseline, 6, 12, 24, and 36 months follow-up. In order to quantify the effect of fusion surgery as compared to decompression alone and number of decompressed levels, we used mixed effects models and accounted for the repeated observations in main outcomes (SSM symptoms and SSM function) over time. In addition to individual patients' random effects, we also fitted random slopes for follow-up time points and compared these two approaches with Akaike's Information Criterion and the chi-square test. Confounders were adjusted with fixed effects for age, sex, body mass index, diabetes, Cumulative Illness Rating Scale musculoskeletal disorders, and duration of symptoms. One hundred thirty-one patients undergoing decompression surgery alone (n = 85) or decompression with fusion surgery (n = 46) were included in this study. In the multiple mixed effects model the adjusted effect of fusion compared with decompression alone surgery on SSM symptoms was 0.06 (95% confidence interval: -0.16-0.27) and -0.07 (95% confidence interval: -0.25-0.10) on SSM function, respectively. Among the patients with degenerative lumbar spinal stenosis and spondylolisthesis our study confirms that in the two groups, decompression alone and decompression with fusion, patients distinctively benefited from surgical treatment. When adjusted for confounders, fusion surgery was not associated with a more

  20. Effect of oxygen-breathing during a decompression-stop on bubble-induced platelet activation after an open-sea air dive: oxygen-stop decompression.

    PubMed

    Pontier, J-M; Lambrechts, K

    2014-06-01

    We highlighted a relationship between decompression-induced bubble formation and platelet micro-particle (PMP) release after a scuba air-dive. It is known that decompression protocol using oxygen-stop accelerates the washout of nitrogen loaded in tissues. The aim was to study the effect of oxygen deco-stop on bubble formation and cell-derived MP release. Healthy experienced divers performed two scuba-air dives to 30 msw for 30 min, one with an air deco-stop and a second with 100% oxygen deco-stop at 3 msw for 9 min. Bubble grades were monitored with ultrasound and converted to the Kisman integrated severity score (KISS). Blood samples for cell-derived micro-particle analysis (AnnexinV for PMP and CD31 for endothelial MP) were taken 1 h before and after each dive. Mean KISS bubble score was significantly lower after the dive with oxygen-decompression stop, compared to the dive with air-decompression stop (4.3 ± 7.3 vs. 32.7 ± 19.9, p < 0.001). After the dive with an air-breathing decompression stop, we observed an increase of the post-dive mean values of PMP (753 ± 245 vs. 381 ± 191 ng/μl, p = 0.003) but no significant change in the oxygen-stop decompression dive (329 ± 215 vs. 381 +/191 ng/μl, p = 0.2). For the post-dive mean values of endothelial MP, there was no significant difference between both the dives. The Oxygen breathing during decompression has a beneficial effect on bubble formation accelerating the washout of nitrogen loaded in tissues. Secondary oxygen-decompression stop could reduce bubble-induced platelet activation and the pro-coagulant activity of PMP release preventing the thrombotic event in the pathogenesis of decompression sickness.

  1. Microvascular stress analysis. Part I: simulation of microvascular anastomoses using finite element analysis.

    PubMed

    Al-Sukhun, Jehad; Lindqvist, Christian; Ashammakhi, Nureddin; Penttilä, Heikki

    2007-03-01

    To develop a finite element model (FEM) to study the effect of the stress and strain, in microvascular anastomoses that result from the geometrical mismatch of anastomosed vessels. FEMs of end-to-end and end-to-side anastomoses were constructed. Simulations were made using finite element software (NISA). We investigated the angle of inset in the end-to-side anastomosis and the discrepancy in the size of the opening in the vessel between the host and recipient vessels. The FEMs were used to predict principal and shear stress and strain at the position of each node. Two types of vascular deformation were predicted during different simulations: longitudinal distortion, and rotational distortion. Stress values ranged from 151.1 to 282.4MPa for the maximum principal stress, from -122.9 to -432.2MPa for the minimum principal stress, and from 122.1 to 333.1MPa for the maximum shear stress. The highest values were recorded when there was a 50% mismatch in the diameter of the vessels at the site of the end-to-end anastomosis. The effect of the vessel's size discrepancy on the blood flow and deformation was remarkable in the end-to-end anastomosis. End-to-side anastomosis was superior to end-to-end anastomosis. FEM is a powerful tool to study vascular deformation, as it predicts deformation and biomechanical processes at sites where physical measurements are likely to remain impossible in living humans.

  2. Decompression tables for inside chamber attendants working at altitude.

    PubMed

    Bell, James; Thombs, Paul A; Davison, William J; Weaver, Lindell K

    2014-01-01

    Hyperbaric oxygen (HBO2) multiplace chamber inside attendants (IAs) are at risk for decompression sickness (DCS). Standard decompression tables are formulated for sea-level use, not for use at altitude. At Presbyterian/St. Luke's Medical Center (Denver, Colorado, 5,924 feet above sea level) and Intermountain Medical Center (Murray, Utah, 4,500 feet), the decompression obligation for IAs is managed with U.S. Navy Standard Air Tables corrected for altitude, Bühlmann Tables, and the Nobendem© calculator. IAs also breathe supplemental oxygen while compressed. Presbyterian/St. Luke's (0.83 atmospheres absolute/atm abs) uses gauge pressure, uncorrected for altitude, at 45 feet of sea water (fsw) (2.2 atm abs) for routine wound care HBO2 and 66 fsw (2.8 atm abs) for carbon monoxide/cyanide poisoning. Presbyterian/St. Luke's provides oxygen breathing for the IAs at 2.2 atm abs. At Intermountain (0.86 atm abs), HBO2 is provided at 2.0 atm abs for routine treatments and 3.0 atm abs for carbon monoxide poisoning. Intermountain IAs breathe intermittent 50% nitrogen/50% oxygen at 3.0 atm abs and 100% oxygen at 2.0 atm abs. The chamber profiles include a safety stop. From 1990-2013, Presbyterian/St. Luke's had 26,900 total IA exposures: 25,991 at 45 fsw (2.2 atm abs) and 646 at 66 fsw (2.8 atm abs); there have been four cases of IA DCS. From 2008-2013, Intermountain had 1,847 IA exposures: 1,832 at 2 atm abs and 15 at 3 atm abs, with one case of IA DCS. At both facilities, DCS incidents occurred soon after the chambers were placed into service. Based on these results, chamber inside attendant risk for DCS at increased altitude is low when the inside attendants breathe supplemental oxygen.

  3. Gender and Decompression Sickness: A Critical Review and Analysis

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The author addressed the following questions: are women at greater risk of decompression sickness and venous gas emboli at certain times in their reproductive cycle, is risk modified by the use of birth control pills (BCP), and is there a difference in overall risk between men and women under the same decompression dose? The summary considers information from the few abstracts and reports that were available. Except for the observation of more Type II DCS in women, particularly in women who fly after diving, there was no compelling evidence of a difference in DCS risk between men and women SCUBA divers. Many women that presented with DCS symptoms seemed to be in or near menses, with statistically fewer cases reported as time increased from menses. There was no compelling evidence that the use of BCP in SCUBA divers increases the risk of DCS. There were insufficient data about VGE from SCUBA diving to make any conclusion about the incidence of VGE and gender. In contrast, there were ample data about VGE from research in altitude chambers. Women produced less VGE and less Grade IV VGE compared to men under the same decompression dose, certainly when resting oxygen prebreathe (PB) was performed prior to ascent to altitude. Dual-cycle ergometry exercise during PB tends to reduce the differences in VGE between men and women. There was no compelling evidence that the risk of altitude DCS was different between men and women. However, a large number of DCS cases were associated with menses, and the use of BCP did seem to put women at a slightly greater risk than those that did not use BCP. There were substantial observations that women comprised a larger number of difficult cases that required complicated medical management.

  4. Piezosurgery for orbital decompression surgery in thyroid associated orbitopathy.

    PubMed

    Ponto, Katharina A; Zwiener, Isabella; Al-Nawas, Bilal; Kahaly, George J; Otto, Anna F; Karbach, Julia; Pfeiffer, Norbert; Pitz, Susanne

    2014-12-01

    The purpose of this study was to assess a piezosurgical device as a novel tool for bony orbital decompression surgery. At a multidisciplinary orbital center, 62 surgeries were performed in 40 patients with thyroid associated orbitopathy (TAO). Within this retrospective case-series, we analyzed the medical records of these consecutive unselected patients. The reduction of proptosis was the main outcome measure. Indications for a two (n = 27, 44%) or three wall (35, 56%) decompression surgery were proptosis (n = 50 orbits, 81%) and optic neuropathy (n = 12, 19%). Piezosurgery enabled precise bone cuts without intraoperative complications. Proptosis decreased from 23.6 ± 2.8 mm (SD) by 3 mm (95% CI: -3.6 to -2.5 mm) after surgery and stayed stable at 3 months (-3 mm, 95% CI: -3.61 to -2.5 mm, p < 0.001, respectively). The effect was higher in those with preoperatively higher values (>24 mm versus ≤ 24 mm: -3.4 mm versus -2.81 mm before discharge from hospital and -4.1 mm versus -2.1 mm at 3 months: p < 0.001, respectively). After a mean long-term follow-up period of 14.6 ± 10.4 months proptosis decreased by further -0.7 ± 2.0 mm (p < 0.001). Signs of optic nerve compression improved after surgery. Infraorbital hypesthesia was present in 11 of 21 (52%) orbits 3 months after surgery. The piezosurgical device is a useful tool for orbital decompression surgery in TAO. By cutting bone selectively, it is precise and reduces the invasiveness of surgery. Nevertheless, no improvement in outcome or reduction in morbidity over conventional techniques has been shown so far. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  5. Arthroscopic Decompression of a Type III Subspine Impingement.

    PubMed

    Ilizaliturri, Víctor M; Arriaga Sánchez, Rubén; Suarez-Ahedo, Carlos

    2016-12-01

    Extra-articular hip impingement refers to a variety of hip disorders causing pain and limited function in young, non-arthritic patients. Recently, there has been an increased focus on analyzing the degree of anterior inferior iliac spine (AIIS) dysmorphism and its correlation with subspine impingement (SSI), defined as abutment between a prominent distal aspect of the AIIS and the anterior aspect of the femoral head-neck junction. Arthroscopic decompression of the AIIS is recognized as an effective treatment for SSI. However, there may be some inherent risks of performing this procedure arthroscopically that require further investigation.

  6. Investigation of Hematologic and Pathologic Response to Decompression.

    DTIC Science & Technology

    1978-05-10

    in tadpole and very young kangaroos . Am. J. Physiol. 120:59—74 , 1937. 12. D’ C’~~~’ B.G. and Swanson , H. Bubble free decompression of blood samples...1955. 24. Takeda , Y. Studies of the metabol i~~ 5 and distribution of fibrino— gen in healthy men with autologous I-labe led fibrinogen. J. Clin...this connective tissue protein. However , the metabolism of bone collagen is affected by hormonal control (l0; 3l) and vitamin influences (3 ;ll). It

  7. Degassing of H2O in a phonolitic melt: A closer look at decompression experiments

    NASA Astrophysics Data System (ADS)

    Marxer, Holger; Bellucci, Philipp; Nowak, Marcus

    2015-05-01

    Melt degassing during magma ascent is controlled by the decompression rate and can be simulated in decompression experiments. H2O-bearing phonolitic melts were decompressed at a super-liquidus T of 1323 K in an internally heated argon pressure vessel, applying continuous decompression (CD) as well as to date commonly used step-wise decompression (SD) techniques to investigate the effect of decompression method on melt degassing. The hydrous melts were decompressed from 200 MPa at nominal decompression rates of 0.0028-1.7 MPa·s- 1. At final pressure (Pfinal), the samples were quenched rapidly at isobaric conditions with ~ 150 K·s- 1. The bubbles in the quenched samples are often deformed and dented. Flow textures in the glass indicate melt transport at high viscosity. We suggest that this observation is due to bubble shrinkage during quench. This general problem was mostly overlooked in the interpretation of experimentally degassed samples to date. Bubble shrinkage due to decreasing molar volume (Vm) of the exsolved H2O in the bubbles occurs during isobaric rapid quench until the melt is too viscous too relax. The decrease of Vm(H2O) during cooling at Pfinal of the experiments results in a decrease of the bubble volume by a shrinking factor Bs: At nominal decompression rates > 0.17 MPa·s- 1 and a Pfinal of 75 MPa, the decompression method has only minor influence on melt degassing. SD and CD result in high bubble number densities of 104-105 mm- 3. Fast P drop leads to immediate supersaturation with H2O in the melt. At such high nominal decompression rates, the diffusional transport of H2O is limited and therefore bubble nucleation is the predominant degassing process. The residual H2O contents in the melts decompressed to 75 MPa increase with nominal decompression rate. After homogeneous nucleation is triggered, CD rates ≤ 0.024 MPa·s- 1 facilitate continuous reduction of the supersaturation by H2O diffusion into previously nucleated bubbles. Bubble number

  8. Effect of Orbital Decompression on Corneal Topography in Patients with Thyroid Ophthalmopathy

    PubMed Central

    Kim, Su Ah; Jung, Su Kyung; Paik, Ji Sun; Yang, Suk-Woo

    2015-01-01

    Objective To evaluate changes in corneal astigmatism in patients undergoing orbital decompression surgery. Methods This retrospective, non randomized comparative study involved 42 eyes from 21 patients with thyroid ophthalmopathy who underwent orbital decompression surgery between September 2011 and September 2014. The 42 eyes were divided into three groups: control (9 eyes), two-wall decompression (25 eyes), and three-wall decompression (8 eyes). The control group was defined as the contralateral eyes of nine patients who underwent orbital decompression surgery in only one eye. Corneal topography (Orbscan II), Hertel exophthalmometry, and intraocular pressure were measured at 1 month before and 3 months after surgery. Corneal topographic parameters analyzed were total astigmatism (TA), steepest axis (SA), central corneal thickness (CCT), and anterior chamber depth (ACD). Results Exophthalmometry values and intraocular pressure decreased significantly after the decompression surgery. The change (absolute value (|x|) of the difference) in astigmatism at the 3 mm zone was significantly different between the decompression group and the controls (p = 0.025). There was also a significant change in the steepest axis at the 3 mm zone between the decompression group and the controls (p = 0.033). An analysis of relevant changes in astigmatism showed that there was a dominant tendency for incyclotorsion of the steepest axis in eyes that underwent decompression surgery. Using Astig PLOT, the mean surgically induced astigmatism (SIA) was 0.21±0.88 D with an axis of 46±22°, suggesting that decompression surgery did change the corneal shape and induced incyclotorsion of the steepest axis. Conclusions There was a significant change in corneal astigmatism after orbital decompression surgery and this change was sufficient to affect the optical function of the cornea. Surgeons and patients should be aware of these changes. PMID:26352432

  9. Treatment of Angina Pectoris Associated with Coronary Microvascular Dysfunction.

    PubMed

    Ong, Peter; Athanasiadis, Anastasios; Sechtem, Udo

    2016-08-01

    Treatment of angina pectoris associated with coronary microvascular dysfunction is challenging as the underlying mechanisms are often diverse and overlapping. Patients with type 1 coronary microvascular dysfunction (i.e. absence of epicardial coronary artery disease and myocardial disease) should receive strict control of their cardiovascular risk factors and thus receive statins and ACE-inhibitors in most cases. Antianginal medication consists of ß-blockers and/or calcium channel blockers. Second line drugs are ranolazine and nicorandil with limited evidence. Despite individually titrated combinations of these drugs up to 30 % of patients have refractory angina. Rho-kinase inhibitors and endothelin-receptor antagonists represent potential drugs that may prove useful in these patients in the future.

  10. Influence of surgical decompression on the expression of inflammatory and tissue repair biomarkers in periapical cysts.

    PubMed

    Rodrigues, Janderson Teixeira; Dos Santos Antunes, Henrique; Armada, Luciana; Pires, Fábio Ramôa

    2017-12-01

    The biologic effects of surgical decompression on the epithelium and connective tissues of periapical cysts are not fully understood. The aim of this study was to evaluate the expression of tissue repair and inflammatory biomarkers in periapical cysts before and after surgical decompression. Nine specimens of periapical cysts treated with decompression before undergoing complete enucleation were immunohistochemically analyzed to investigate the expression of interleukin-1β, tumor necrosis factor-α, transforming growth factor-β1, matrix metalloproteinase-9, Ki-67, and epidermal growth factor receptor. Expression of the biomarkers was classified as positive, focal, or negative. Ki-67 immunoexpression was calculated as a cell proliferation index. The expression of the biomarkers was compared in the specimens from decompression and from the final surgical procedure. Computed tomography demonstrated that volume was reduced in all cysts after decompression. There were no differences in the immunoexpression of the proinflammatory and tissue repair biomarkers when comparing the specimens obtained before and after the decompression. Surgical decompression was efficient in reducing the volume of periapical cysts before complete enucleation. When comparing the specimens obtained from surgical decompression and from complete surgical removal, the immunohistochemical analysis did not show a decrease in proinflammatory biomarkers; neither did it show an increase in tissue repair biomarkers. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Chronic Decompression Illness Cognitive Dysfunction Improved with Hyperbaric Oxygen: A Case Report

    DTIC Science & Technology

    2018-11-09

    Altitude chamber exposures are used for training to allow aircrew to experience their hypoxia and pressure effect symptoms. Decompression illness ...chamber decompression illness is around 0.25% (1). Because the evolution of gas within the tissue or vasculature is being treated upon recompression

  12. Surgical decompression is associated with decreased mortality in patients with sepsis and ureteral calculi.

    PubMed

    Borofsky, Michael S; Walter, Dawn; Shah, Ojas; Goldfarb, David S; Mues, Adam C; Makarov, Danil V

    2013-03-01

    The combination of sepsis and ureteral calculus is a urological emergency. Traditional teaching advocates urgent decompression with nephrostomy tube or ureteral stent placement, although published outcomes validating this treatment are lacking. National practice patterns for such scenarios are currently undefined. Using a retrospective study design, we defined the surgical decompression rate in patients admitted to the hospital with severe infection and ureteral calculi. We determined whether a mortality benefit is associated with this intervention. Patient demographics and hospital characteristics were extracted from the 2007 to 2009 Nationwide Inpatient Sample. We identified 1,712 patients with ureteral calculi and sepsis. Multivariate logistic regression was performed to determine the association between mortality and surgical decompression. Of the patients 78% underwent surgical decompression. Mortality was higher in those not treated with surgical decompression (19.2% vs 8.82%, p <0.001). Lack of surgical decompression was independently associated with an increased OR of mortality even when adjusting for patient demographics, comorbidities and geographic region of treatment (OR 2.6, 95% CI 1.9-3.7). Absent surgical decompression is associated with higher odds of mortality in patients with sepsis and ureteral calculi. Further research to determine predictors of surgical decompression is necessary to ensure that all patients have access to this life saving therapy. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  13. Deep lateral wall orbital decompression following strabismus surgery in patients with Type II ophthalmic Graves' disease.

    PubMed

    Ellis, Michael P; Broxterman, Emily C; Hromas, Alan R; Whittaker, Thomas J; Sokol, Jason A

    2018-01-10

    Surgical management of ophthalmic Graves' disease traditionally involves, in order, orbital decompression, followed by strabismus surgery and eyelid surgery. Nunery et al. previously described two distinct sub-types of patients with ophthalmic Graves' disease; Type I patients exhibit no restrictive myopathy (no diplopia) as opposed to Type II patients who do exhibit restrictive myopathy (diplopia) and are far more likely to develop new-onset worsening diplopia following medial wall and floor decompression. Strabismus surgery involving extra-ocular muscle recession has, in turn, been shown to potentially worsen proptosis. Our experience with Type II patients who have already undergone medial wall and floor decompression and strabismus surgery found, when additional decompression is necessary, deep lateral wall decompression (DLWD) appears to have a low rate of post-operative primary-gaze diplopia. A case series of four Type II ophthalmic Graves' disease patients, all of whom had already undergone decompression and strabismus surgery, and went on to develop worsening proptosis or optic nerve compression necessitating further decompression thereafter. In all cases, patients were treated with DLWD. Institutional Review Board approval was granted by the University of Kansas. None of the four patients treated with this approach developed recurrent primary-gaze diplopia or required strabismus surgery following DLWD. While we still prefer to perform medial wall and floor decompression as the initial treatment for ophthalmic Graves' disease, for proptosis following consecutive strabismus surgery, DLWD appears to be effective with a low rate of recurrent primary-gaze diplopia.

  14. Targeting Microvascular Pericytes in Angiogenic Vessels of Prostate Cancer

    DTIC Science & Technology

    2005-04-01

    endothelial cells (BEC) were identified using a cocktail of rat antibodies against mouse endoglin ( CD 105), PECAM-1 (CD3 1), and VEGF receptor-2 (flk...immunohistochemistry, and imaging angiogenic tufts composed of endothelial cells positive for endoglin ( CD 105), PECAM- I (CD3 1), and VEGF receptor...TYPE AND DATES COVERED (Leave blank) - April 2005 Annual (1 Apr 2004 - 31 Mar 2005) 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Targeting Microvascular

  15. Pulmonary Nanoparticle Exposure Disrupts Systemic Microvascular Nitric Oxide Signaling

    PubMed Central

    Nurkiewicz, Timothy R.; Porter, Dale W.; Hubbs, Ann F.; Stone, Samuel; Chen, Bean T.; Frazer, David G.; Boegehold, Matthew A.; Castranova, Vincent

    2009-01-01

    We have shown that pulmonary nanoparticle exposure impairs endothelium dependent dilation in systemic arterioles. However, the mechanism(s) through which this effect occurs is/are unclear. The purpose of this study was to identify alterations in the production of reactive species and endogenous nitric oxide (NO) after nanoparticle exposure, and determine the relative contribution of hemoproteins and oxidative enzymes in this process. Sprague-Dawley rats were exposed to fine TiO2 (primary particle diameter ∼1 μm) and TiO2 nanoparticles (primary particle diameter ∼21 nm) via aerosol inhalation at depositions of 4–90 μg per rat. As in previous intravital experiments in the spinotrapezius muscle, dose-dependent arteriolar dilations were produced by intraluminal infusions of the calcium ionophore A23187. Nanoparticle exposure robustly attenuated these endothelium-dependent responses. However, this attenuation was not due to altered microvascular smooth muscle NO sensitivity because nanoparticle exposure did not alter arteriolar dilations in response to local sodium nitroprusside iontophoresis. Nanoparticle exposure significantly increased microvascular oxidative stress by ∼60%, and also elevated nitrosative stress fourfold. These reactive stresses coincided with a decreased NO production in a particle deposition dose-dependent manner. Radical scavenging, or inhibition of either myeloperoxidase or nicotinamide adenine dinucleotide phosphate oxidase (reduced) oxidase partially restored NO production as well as normal microvascular function. These results indicate that in conjunction with microvascular dysfunction, nanoparticle exposure also decreases NO bioavailability through at least two functionally distinct mechanisms that may mutually increase local reactive species. PMID:19270016

  16. Three-Dimensional Microvascular Fiber-Reinforced Composites

    DTIC Science & Technology

    2011-03-01

    are varied to meet the desired design criteria. The interstitial pore space between fi bers is infi ltrated with a low- viscosity thermosetting resin...depolymerization and monomer vaporization results in a 3D microvascular network integrated into a structural composite; d) fl uid (yellow) fi lls...VaSC method uses commercially available materials and can be seamlessly integrated with conventional fi ber-reinforced composite manufacturing

  17. Preventing microvascular complications in type 1 diabetes mellitus

    PubMed Central

    Viswanathan, Vijay

    2015-01-01

    Patients with complications of diabetes such as retinopathy, nephropathy, and cardiovascular complications have increased hospital stay with greater economic burden. Prevention of complications should be started before the onset of type 1 diabetes mellitus (T1DM) by working on risk factors and thereafter by intervention upon confirmatory diagnosis which can prevent further damage to β-cells. The actual risk of getting microvascular complications like microalbuminuria and retinopathy progression starts at glycated hemoglobin (HbA1c) level of 7%. As per the American Diabetes Association, a new pediatric glycemic control target of HbA1c <7.5% across all ages replaces previous guidelines that had called for different targets by age. Evidence shows that prevalence of microvascular complications is greater in patients with age >20 years as compared to patients <10 years of age. Screening of these complications should be done regularly, and appropriate preventive strategies should be followed. Angiotensin converting enzyme inhibitors and angiotensin II receptor blocker reduce progression from microalbuminuria to macroalbuminuria and increase the regression rate to normoalbuminuria. Diabetic microvascular complications can be controlled with tight glycemic therapy, dyslipidemia management and blood pressure control along with renal function monitoring, lifestyle changes, including smoking cessation and low-protein diet. An integrated and personalized care would reduce the risk of development of microvascular complications in T1DM patients. The child with diabetes who receives limited care is more likely to develop long-term complications at an earlier age. Screening for subclinical complications and early interventions with intensive therapy is the need of the hour. PMID:25941647

  18. Reversibility of Retinal Microvascular Changes in Severe Falciparum Malaria

    PubMed Central

    Maude, Richard J.; Kingston, Hugh W. F.; Joshi, Sonia; Mohanty, Sanjib; Mishra, Saroj K.; White, Nicholas J.; Dondorp, Arjen M.

    2014-01-01

    Malarial retinopathy allows detailed study of central nervous system vascular pathology in living patients with severe malaria. An adult with cerebral malaria is described who had prominent retinal whitening with corresponding retinal microvascular obstruction, vessel dilatation, increased vascular tortuosity, and blood retinal barrier leakage with decreased visual acuity, all of which resolved on recovery. Additional study of these features and their potential role in elucidating the pathogenesis of cerebral malaria is warranted. PMID:24935949

  19. Reversibility of retinal microvascular changes in severe falciparum malaria.

    PubMed

    Maude, Richard J; Kingston, Hugh W F; Joshi, Sonia; Mohanty, Sanjib; Mishra, Saroj K; White, Nicholas J; Dondorp, Arjen M

    2014-09-01

    Malarial retinopathy allows detailed study of central nervous system vascular pathology in living patients with severe malaria. An adult with cerebral malaria is described who had prominent retinal whitening with corresponding retinal microvascular obstruction, vessel dilatation, increased vascular tortuosity, and blood retinal barrier leakage with decreased visual acuity, all of which resolved on recovery. Additional study of these features and their potential role in elucidating the pathogenesis of cerebral malaria is warranted. © The American Society of Tropical Medicine and Hygiene.

  20. Computational Modeling and Design of Actively-Cooled Microvascular Materials

    DTIC Science & Technology

    2012-06-14

    the oscillations of the microchannel for exchanging the heat between the top and bottom edges become ineffective for reducing the temperature of the...Miniature loop heat pipes for electronics cooling, Appl. Therm. Eng. 23 (9) (2003) 1125–1135. [11] X. Wei, Y. Joshi, M.K. Patterson, Experimental and...systems ( MEMS ) [10–12]. In many of these applications, biomimicry has been used as an inspiration for the design of the microvascular sys- tem, while

  1. Microvascular Perfusion Changes following Transarterial Hepatic Tumor Embolization

    PubMed Central

    Johnson, Carmen Gacchina; Sharma, Karun V.; Levy, Elliot B.; Woods, David L.; Morris, Aaron H.; Bacher, John D.; Lewis, Andrew L.; Wood, Bradford J.; Dreher, Matthew R.

    2015-01-01

    Purpose To quantify changes in tumor microvascular (< 1 mm) perfusion relative to commonly used angiographic endpoints. Materials and Methods Rabbit Vx2 liver tumors were embolized with 100–300-µm LC Bead particles to endpoints of substasis or complete stasis (controls were not embolized). Microvascular perfusion was evaluated by delivering two different fluorophore-conjugated perfusion markers (ie, lectins) through the catheter before embolization and 5 min after reaching the desired angiographic endpoint. Tumor microvasculature was labeled with an anti-CD31 antibody and analyzed with fluorescence microscopy for perfusion marker overlap/mismatch. Data were analyzed by analysis of variance and post hoc test (n = 3–5 per group; 18 total). Results Mean microvascular density was 70 vessels/mm2 ± 17 (standard error of the mean), and 81% ± 1 of microvasculature (ie, CD31+ structures) was functionally perfused within viable Vx2 tumor regions. Embolization to the extent of substasis eliminated perfusion in 37% ± 9 of perfused microvessels (P > .05 vs baseline), whereas embolization to the extent of angiographic stasis eliminated perfusion in 56% ± 8 of perfused microvessels. Persistent microvascular perfusion following embolization was predominantly found in the tumor periphery, adjacent to normal tissue. Newly perfused microvasculature was evident following embolization to substasis but not when embolization was performed to complete angiographic stasis. Conclusions Nearly half of tumor microvasculature remained patent despite embolization to complete angiographic stasis. The observed preservation of tumor microvasculature perfusion with angiographic endpoints of substasis and stasis may have implications for tumor response to embolotherapy. PMID:26321051

  2. Endothelial glycocalyx dysfunction in disease: albuminuria and increased microvascular permeability.

    PubMed

    Salmon, Andrew H J; Satchell, Simon C

    2012-03-01

    Appreciation of the glomerular microcirculation as a specialized microcirculatory bed, rather than as an entirely separate entity, affords important insights into both glomerular and systemic microvascular pathophysiology. In this review we compare regulation of permeability in systemic and glomerular microcirculations, focusing particularly on the role of the endothelial glycocalyx, and consider the implications for disease processes. The luminal surface of vascular endothelium throughout the body is covered with endothelial glycocalyx, comprising surface-anchored proteoglycans, supplemented with adsorbed soluble proteoglycans, glycosaminoglycans and plasma constituents. In both continuous and fenestrated microvessels, this endothelial glycocalyx provides resistance to the transcapillary escape of water and macromolecules, acting as an integral component of the multilayered barrier provided by the walls of these microvessels (ie acting in concert with clefts or fenestrae across endothelial cell layers, basement membranes and pericytes). Dysfunction of any of these capillary wall components, including the endothelial glycocalyx, can disrupt normal microvascular permeability. Because of its ubiquitous nature, damage to the endothelial glycocalyx alters the permeability of multiple capillary beds: in the glomerulus this is clinically apparent as albuminuria. Generalized damage to the endothelial glycocalyx can therefore manifest as both albuminuria and increased systemic microvascular permeability. This triad of altered endothelial glycocalyx, albuminuria and increased systemic microvascular permeability occurs in a number of important diseases, such as diabetes, with accumulating evidence for a similar phenomenon in ischaemia-reperfusion injury and infectious disease. The detection of albuminuria therefore has implications for the function of the microcirculation as a whole. The importance of the endothelial glycocalyx for other aspects of vascular function

  3. A metastable liquid melted from a crystalline solid under decompression

    NASA Astrophysics Data System (ADS)

    Lin, Chuanlong; Smith, Jesse S.; Sinogeikin, Stanislav V.; Kono, Yoshio; Park, Changyong; Kenney-Benson, Curtis; Shen, Guoyin

    2017-01-01

    A metastable liquid may exist under supercooling, sustaining the liquid below the melting point such as supercooled water and silicon. It may also exist as a transient state in solid-solid transitions, as demonstrated in recent studies of colloidal particles and glass-forming metallic systems. One important question is whether a crystalline solid may directly melt into a sustainable metastable liquid. By thermal heating, a crystalline solid will always melt into a liquid above the melting point. Here we report that a high-pressure crystalline phase of bismuth can melt into a metastable liquid below the melting line through a decompression process. The decompression-induced metastable liquid can be maintained for hours in static conditions, and transform to crystalline phases when external perturbations, such as heating and cooling, are applied. It occurs in the pressure-temperature region similar to where the supercooled liquid Bi is observed. Akin to supercooled liquid, the pressure-induced metastable liquid may be more ubiquitous than we thought.

  4. Gender not a factor for altitude decompression sickness risk

    NASA Technical Reports Server (NTRS)

    Webb, James T.; Kannan, Nandini; Pilmanis, Andrew A.

    2003-01-01

    INTRODUCTION: Early, retrospective reports of the incidence of altitude decompression sickness (DCS) during altitude chamber training exposures indicated that women were more susceptible than men. We hypothesized that a controlled, prospective study would show no significant difference. METHODS: We conducted 25 altitude chamber decompression exposure profiles. A total of 291 human subjects, 197 men and 94 women, underwent 961 exposures to simulated altitude for up to 8 h, using zero to 4 h of preoxygenation. Throughout the exposures, subjects breathed 100% oxygen, rested or performed mild or strenuous exercise, and were monitored for precordial venous gas emboli (VGE) and DCS symptoms. RESULTS: No significant differences in DCS incidence were observed between men (49.5%) and women (45.3%). However, VGE occurred at significantly higher rates among men than women under the same exposure conditions, 69.3% and 55.0% respectively. Women using hormonal contraception showed significantly greater susceptibility to DCS than those not using hormonal contraception during the latter two weeks of the menstrual cycle. Significantly higher DCS incidence was observed in the heaviest men, in women with the highest body fat, and in subjects with the highest body mass indices and lowest levels of fitness. CONCLUSION: No differences in altitude DCS incidence were observed between the sexes under our test conditions, although men developed VGE more often than women. Age and height showed no significant influence on DCS incidence, but persons of either sex with higher body mass index and lower physical fitness developed DCS more frequently.

  5. A metastable liquid melted from a crystalline solid under decompression

    DOE PAGES

    Lin, Chuanlong; Smith, Jesse S.; Sinogeikin, Stanislav V.; ...

    2017-01-23

    A metastable liquid may exist under supercooling, sustaining the liquid below the melting point such as supercooled water and silicon. It may also exist as a transient state in solid–solid transitions, as demonstrated in recent studies of colloidal particles and glass-forming metallic systems. One important question is whether a crystalline solid may directly melt into a sustainable metastable liquid. By thermal heating, a crystalline solid will always melt into a liquid above the melting point. Here we report that a high-pressure crystalline phase of bismuth can melt into a metastable liquid below the melting line through a decompression process. Themore » decompression-induced metastable liquid can be maintained for hours in static conditions, and transform to crystalline phases when external perturbations, such as heating and cooling, are applied. It occurs in the pressure–temperature region similar to where the supercooled liquid Bi is observed. Finally, akin to supercooled liquid, the pressure-induced metastable liquid may be more ubiquitous than we thought.« less

  6. 2014 Decompression Sickness/Extravehicular Activity Risks Standing Review Panel

    NASA Technical Reports Server (NTRS)

    Steinberg, Susan

    2015-01-01

    The 2014 Decompression Sickness (DCS)/Extravehicular Activity (EVA) Risks Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on November 4 - 5, 2014. The SRP reviewed the updated Evidence Reports for The Risk of Decompression Sickness (from here on referred to as the 2014 DCS Evidence Report) and the Risk of Injury and Compromised Performance due to EVA Operations (from here on referred to as the 2014 EVA Evidence Report), as well as the Research Plans for these Risks. The SRP appreciated the time and effort that the DCS and EVA disciplines put into their review documents and presentations. The SRP felt that the 2014 DCS Evidence Report and the 2014 EVA Evidence Reports were very thorough and addressed the majority of the known DCS and EVA issues. The researchers at NASA Johnson Space Center (JSC) have the knowledge base to deal with the DCS and EVA issues. Overall, the SRP thinks the DCS and EVA research teams have compiled excellent reports which address the majority of the literature and background information.

  7. Case Descriptions and Observations About Cutis Marmorata From Hypobaric Decompressions

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Pilmanis, Andrew A.; Webb, James T.

    2002-01-01

    There is disagreement about the pathophysiology, classification, and treatment of cutis marmorata (CM), so there is disagreement about the disposition and medical status of a person that had CM. CM is rare, associated with stressful decompressions, and may be associated with serious signs and symptoms of decompression sickness (DCS). CM presents as purple or bluish-red skin mottling, often in the pectoral region, shoulders, chest, or upper abdomen. It is unethical to induce CM in humans so all information comes from retrospective analysis of case reports, or from animal models. A literature search, seven recent case reports from the Johnson Space Center and Brooks Air Force Base Hypobaric DCS Databases, interviews with DCS treatment experts, and responses to surveys provided the factual information used to arrive at our conclusions and recommendations. The "weight of evidence" indicates that CM is a local, not centrally mediated or systemic response to bubbles. It is unclear whether obstruction of arterial or venous blood flow is the primary insult since the lesion is reported under either condition. Any neurological or cardiovascular involvements are coincidental, developing along the same time course. The skin could be the source of the bubbles due to its mass, the associated layer of fat, and the variable nature of skin blood flow. CM should not be categorized as Type II DCS, should be included with other skin manifestations in a category called cutaneous DCS, and hyperbaric treatment is only needed if ground level oxygen is ineffective in the case of altitude-induced CM.

  8. Tension pneumothorax secondary to automatic mechanical compression decompression device.

    PubMed

    Hutchings, A C; Darcy, K J; Cumberbatch, G L A

    2009-02-01

    The details are presented of the first published case of a tension pneumothorax induced by an automatic compression-decompression (ACD) device during cardiac arrest. An elderly patient collapsed with back pain and, on arrival of the crew, was in pulseless electrical activity (PEA) arrest. He was promptly intubated and correct placement of the endotracheal tube was confirmed by noting equal air entry bilaterally and the ACD device applied. On the way to the hospital he was noted to have absent breath sounds on the left without any change in the position of the endotracheal tube. Needle decompression of the left chest caused a hiss of air but the patient remained in PEA. Intercostal drain insertion in the emergency department released a large quantity of air from his left chest but without any change in his condition. Post-mortem examination revealed a ruptured abdominal aortic aneurysm as the cause of death. Multiple left rib fractures and a left lung laceration secondary to the use of the ACD device were also noted, although the pathologist felt that the tension pneumothorax had not contributed to the patient's death. It is recommended that a simple or tension pneumothorax should be considered when there is unilateral absence of breath sounds in addition to endobronchial intubation if an ACD device is being used.

  9. A metastable liquid melted from a crystalline solid under decompression

    PubMed Central

    Lin, Chuanlong; Smith, Jesse S.; Sinogeikin, Stanislav V.; Kono, Yoshio; Park, Changyong; Kenney-Benson, Curtis; Shen, Guoyin

    2017-01-01

    A metastable liquid may exist under supercooling, sustaining the liquid below the melting point such as supercooled water and silicon. It may also exist as a transient state in solid–solid transitions, as demonstrated in recent studies of colloidal particles and glass-forming metallic systems. One important question is whether a crystalline solid may directly melt into a sustainable metastable liquid. By thermal heating, a crystalline solid will always melt into a liquid above the melting point. Here we report that a high-pressure crystalline phase of bismuth can melt into a metastable liquid below the melting line through a decompression process. The decompression-induced metastable liquid can be maintained for hours in static conditions, and transform to crystalline phases when external perturbations, such as heating and cooling, are applied. It occurs in the pressure–temperature region similar to where the supercooled liquid Bi is observed. Akin to supercooled liquid, the pressure-induced metastable liquid may be more ubiquitous than we thought. PMID:28112152

  10. Transesophageal Echocardiographic Study of Decompression-Induced Venous Gas Emboli

    NASA Technical Reports Server (NTRS)

    Butler, B. D.; Morris, W. P.

    1995-01-01

    Transesophageal echo-cardiography was used to evaluate venous bubbles produced in nine anesthetized dogs following decompression from 2.84 bar after 120 min at pressure. In five dogs a pulsed Doppler cuff probe was placed around the inferior vena cava for bubble grade determination. The transesophageal echo images demonstrated several novel or less defined events. In each case where the pulmonary artery was clearly visualized, the venous bubbles were seen to oscillate back and forth several times, bringing into question the effect of coincidental counting in routine bubble grade analysis using precordial Doppler. A second finding was that in all cases, extensive bubbling occurred in the portal veins with complete extraction by the liver sinusoids, with one exception where a portal-to-hepatic venous anastomosis was observed. Compression of the bowel released copious numbers of bubbles into the portal veins, sometimes more than were released into the inferior vena cava. Finally, large masses of foam were routinely observed in the non-dependent regions of the inferior vena cava that not only delayed the appearance of bubbles in the pulmonary artery but also allowed additional opportunity for further reaction with blood products and for coalescence to occur before reaching the pulmonary microcirculation. These novel observations are discussed in relation to the decompression process.

  11. The mechanics of decompressive craniectomy: Bulging in idealized geometries

    NASA Astrophysics Data System (ADS)

    Weickenmeier, Johannes; Kuhl, Ellen; Goriely, Alain

    2016-11-01

    In extreme cases of traumatic brain injury or a stroke, the resulting uncontrollable swelling of the brain may lead to a harmful increase of the intracranial pressure. As a common measure for immediate release of pressure on the brain, part of the skull is surgically removed allowing for the brain to bulge outwards, a procedure known as a decompressive craniectomy. During this excessive brain swelling, the affected tissue typically undergoes large deformations resulting in a complex three-dimensional mechanical loading state with several important implications on optimal treatment strategies and outcome. Here, as a first step towards a better understanding of the mechanics of a decompressive craniectomy, we consider simple models for the bulging of elastic solids under geometric constraints representative of the surgical intervention. In small deformations and simple geometries, the exact solution of this problem is derived from the theory of contact mechanics. The analysis of these solutions reveals a number of interesting generic features relevant for the mechanics of craniectomy.

  12. Evaluation of gravimetric techniques to estimate the microvascular filtration coefficient

    PubMed Central

    Dongaonkar, R. M.; Laine, G. A.; Stewart, R. H.

    2011-01-01

    Microvascular permeability to water is characterized by the microvascular filtration coefficient (Kf). Conventional gravimetric techniques to estimate Kf rely on data obtained from either transient or steady-state increases in organ weight in response to increases in microvascular pressure. Both techniques result in considerably different estimates and neither account for interstitial fluid storage and lymphatic return. We therefore developed a theoretical framework to evaluate Kf estimation techniques by 1) comparing conventional techniques to a novel technique that includes effects of interstitial fluid storage and lymphatic return, 2) evaluating the ability of conventional techniques to reproduce Kf from simulated gravimetric data generated by a realistic interstitial fluid balance model, 3) analyzing new data collected from rat intestine, and 4) analyzing previously reported data. These approaches revealed that the steady-state gravimetric technique yields estimates that are not directly related to Kf and are in some cases directly proportional to interstitial compliance. However, the transient gravimetric technique yields accurate estimates in some organs, because the typical experimental duration minimizes the effects of interstitial fluid storage and lymphatic return. Furthermore, our analytical framework reveals that the supposed requirement of tying off all draining lymphatic vessels for the transient technique is unnecessary. Finally, our numerical simulations indicate that our comprehensive technique accurately reproduces the value of Kf in all organs, is not confounded by interstitial storage and lymphatic return, and provides corroboration of the estimate from the transient technique. PMID:21346245

  13. Endothelial Progenitor Cells in Diabetic Microvascular Complications: Friends or Foes?

    PubMed

    Yu, Cai-Guo; Zhang, Ning; Yuan, Sha-Sha; Ma, Yan; Yang, Long-Yan; Feng, Ying-Mei; Zhao, Dong

    2016-01-01

    Despite being featured as metabolic disorder, diabetic patients are largely affected by hyperglycemia-induced vascular abnormality. Accumulated evidence has confirmed the beneficial effect of endothelial progenitor cells (EPCs) in coronary heart disease. However, antivascular endothelial growth factor (anti-VEGF) treatment is the main therapy for diabetic retinopathy and nephropathy, indicating the uncertain role of EPCs in the pathogenesis of diabetic microvascular disease. In this review, we first illustrate how hyperglycemia induces metabolic and epigenetic changes in EPCs, which exerts deleterious impact on their number and function. We then discuss how abnormal angiogenesis develops in eyes and kidneys under diabetes condition, focusing on "VEGF uncoupling with nitric oxide" and "competitive angiopoietin 1/angiopoietin 2" mechanisms that are shared in both organs. Next, we dissect the nature of EPCs in diabetic microvascular complications. After we overview the current EPCs-related strategies, we point out new EPCs-associated options for future exploration. Ultimately, we hope that this review would uncover the mysterious nature of EPCs in diabetic microvascular disease for therapeutics.

  14. 4D microvascular imaging based on ultrafast Doppler tomography.

    PubMed

    Demené, Charlie; Tiran, Elodie; Sieu, Lim-Anna; Bergel, Antoine; Gennisson, Jean Luc; Pernot, Mathieu; Deffieux, Thomas; Cohen, Ivan; Tanter, Mickael

    2016-02-15

    4D ultrasound microvascular imaging was demonstrated by applying ultrafast Doppler tomography (UFD-T) to the imaging of brain hemodynamics in rodents. In vivo real-time imaging of the rat brain was performed using ultrasonic plane wave transmissions at very high frame rates (18,000 frames per second). Such ultrafast frame rates allow for highly sensitive and wide-field-of-view 2D Doppler imaging of blood vessels far beyond conventional ultrasonography. Voxel anisotropy (100 μm × 100 μm × 500 μm) was corrected for by using a tomographic approach, which consisted of ultrafast acquisitions repeated for different imaging plane orientations over multiple cardiac cycles. UFT-D allows for 4D dynamic microvascular imaging of deep-seated vasculature (up to 20 mm) with a very high 4D resolution (respectively 100 μm × 100 μm × 100 μm and 10 ms) and high sensitivity to flow in small vessels (>1 mm/s) for a whole-brain imaging technique without requiring any contrast agent. 4D ultrasound microvascular imaging in vivo could become a valuable tool for the study of brain hemodynamics, such as cerebral flow autoregulation or vascular remodeling after ischemic stroke recovery, and, more generally, tumor vasculature response to therapeutic treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Microvascular transplantation and replantation of the dog submandibular gland.

    PubMed

    Su, Wan Fu; Jen, Yee Min; Chen, Shyi Gen; Nieh, Shin; Wang, Chih-Hung

    2006-05-01

    Transplantation and replantation of the submandibular gland with microvascular techniques were demonstrated in a previous study, with good gland survival. The application of radiation on the neck bed was attempted to address an actual clinical scenario in this study. Five canine submandibular glands were transplanted using microvascular techniques to the ipsilateral femoral system. Radiotherapy at a dosage level of 3,600 cGy using 600 cGy q.d was delivered to the nasopharyngeal and neck regions 2 weeks after transplantation. The transferred glands were then reintroduced into the original but radiated neck bed. The glands were harvested for histological examination 8 weeks later. Four of five canine submandibular glands can withstand microvascular transplantation and then replantation into a radiated neck bed for at least 8 weeks. However, the salivary function was depleted. The canine submandibular gland can survive the transplantation and replantation for at least 8 weeks in spite of precipitating radiation insult on the neck bed for 3 weeks. Neurorraphy is, however, essential to maintaining the glandular function.

  16. Biological basis and pathological relevance of microvascular thrombosis.

    PubMed

    Pfeiler, Susanne; Massberg, Steffen; Engelmann, Bernd

    2014-05-01

    Microvascular thrombosis indicates a pathological occlusion of microvessels by fibrin- and/or platelet-rich thrombi. It is observed during systemic infections, cancer, myocardial infarction, stroke, neurodegenerative diseases and in thrombotic microangiopathies. Microvessel thrombosis can cause greatly differing symptoms that range from limited changes in plasma coagulation markers to severe multi-organ failure. Because microvessel thrombi are difficult to detect and often occur only transiently, their importance for disease development and host biology is likely markedly under-appreciated. Recently, clear indications for a biological basis of microvascular thrombosis have been obtained. During systemic infections microvessel thrombosis can mediate an intravascular innate immune response (immunothrombosis). This biological form of thrombosis is based on the generation of fibrin inside blood vessels and is critically triggered by neutrophils and their interactions with platelets which result in the release of neutrophil extracellular traps (extracellular nucleosomes). Immunothrombosis is critically supported by neutrophil elastase and the activator molecules of blood coagulation tissue factor and factor XII. Identification of the biological driving forces of microvascular thrombosis should help to elucidate the mechanisms promoting pathological vessel occlusions in both microvessels and large vessels. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Microvascular Remodeling and Wound Healing: A Role for Pericytes

    PubMed Central

    Dulmovits, Brian M.; Herman, Ira M.

    2012-01-01

    Physiologic wound healing is highly dependent on the coordinated functions of vascular and non-vascular cells. Resolution of tissue injury involves coagulation, inflammation, formation of granulation tissue, remodeling and scarring. Angiogenesis, the growth of microvessels the size of capillaries, is crucial for these processes, delivering blood-borne cells, nutrients and oxygen to actively remodeling areas. Central to angiogenic induction and regulation is microvascular remodeling, which is dependent upon capillary endothelial cell and pericyte interactions. Despite our growing knowledge of pericyte-endothelial cell crosstalk, it is unclear how the interplay among pericytes, inflammatory cells, glia and connective tissue elements shape microvascular injury response. Here, we consider the relationships that pericytes form with the cellular effectors of healing in normal and diabetic environments, including repair following injury and vascular complications of diabetes, such as diabetic macular edema and proliferative diabetic retinopathy. In addition, pericytes and stem cells possessing “pericyte-like” characteristics are gaining considerable attention in experimental and clinical efforts aimed at promoting healing or eradicating ocular vascular proliferative disorders. As the origin, identification and characterization of microvascular pericyte progenitor populations remains somewhat ambiguous, the molecular markers, structural and functional characteristics of pericytes will be briefly reviewed. PMID:22750474

  18. [Theoretical evaluation of the risk of decompression illness during simulated extravehicular activity].

    PubMed

    Nikolaev, V P

    2008-01-01

    Theoretical analysis of the risk of decompression illness (DI) during extravehicular activity following the Russian and NASA decompression protocols (D-R and D-US, respectively) was performed. In contrast to the tradition approach to decompression stress evaluation by the factor of tissue supersaturation with nitrogen, our probabilistic theory of decompression safety provides a completely reasoned evaluation and comparison of the levels of hazard of these decompression protocols. According to this theory, the function of cumulative DI risk is equal to the sum of functions of cumulative risk of lesion of all body tissues by gas bubbles and their supersaturation by solute gases. Based on modeling of dynamics of these functions, growth of the DI cumulative risk in the course of D-R and D-US follows essentially similar trajectories within the time-frame of up to 330 minutes. However, further extension of D-US but not D-R raises the risk of DI drastically.

  19. Topical Combinations to Treat Microvascular Dysfunction of Chronic Postischemia Pain

    PubMed Central

    Laferrière, André; Abaji, Rachid; Tsai, Cheng-Yu Mark; Ragavendran, J. Vaigunda; Coderre, Terence J.

    2015-01-01

    Background Growing evidence indicates that patients with complex regional pain syndrome (CRPS) exhibit tissue abnormalities caused by microvascular dysfunction in the blood vessels of skin, muscle and nerve. We tested whether topical combinations aimed at improving microvascular function would relieve allodynia in an animal model of CRPS. We hypothesized that topical administration of either α2-adrenergic (α2A) receptor agonists or nitric oxide (NO) donors given to increase arterial blood flow, combined with either phosphatidic acid (PA) or phosphodiesterase (PDE) inhibitors to increase capillary blood flow, would effectively reduce allodynia and signs of microvascular dysfunction in the animal model of chronic pain. Methods Mechanical allodynia was induced in the hind paws of rats with chronic postischemia pain (CPIP). Allodynia was assessed before and after topical application of vehicle, single drugs or combinations of an α2A receptor agonist (apraclonidine) or an NO donor (linsidomine), with PA or PDE inhibitors (lisofylline, pentoxifylline). A topical combination of apraclonidine + lisofylline was also evaluated for its effects on a measure of microvascular function (post-occlusive reactive hyperemia) and tissue oxidative capacity (formazan production by tetrazolium reduction) in CPIP rats. Results Each of the single topical drugs produced significant dose-dependent antiallodynic effects compared to vehicle in CPIP rats (n = 30), and the antiallodynic dose-response curves of either PA or PDE inhibitors were shifted 5 to 10 fold to the left when combined with nonanalgesic doses of α2A receptor agonists or NO donors (n = 28). The potent antiallodynic effects of ipsilateral treatment with combinations of α2A receptor agonists or NO donors with PA or PDE inhibitors, were not reproduced by the same treatment of the contralateral hindpaw (n = 28). Topical combinations produced antiallodynic effects lasting up to 6 h (n = 15), and were significantly enhanced by

  20. Plants survive rapid decompression: Implications for bioregenerative life support

    NASA Astrophysics Data System (ADS)

    Wheeler, R. M.; Wehkamp, C. A.; Stasiak, M. A.; Dixon, M. A.; Rygalov, V. Y.

    2011-05-01

    Radish (Raphanus sativus), lettuce (Latuca sativa), and wheat (Triticum aestivum) plants were grown at either 98 kPa (ambient) or 33 kPa atmospheric pressure with constant 21 kPa oxygen and 0.12 kPa carbon dioxide in atmospherically closed pressure chambers. All plants were grown rockwool using recirculating hydroponics with a complete nutrient solution. At 20 days after planting, chamber pressures were pumped down as rapidly as possible, reaching 5 kPa after about 5 min and ˜1.5 kPa after about 10 min. The plants were held at 1.5 kPa for 30 min and then pressures were restored to their original settings. Temperature (22 °C) and humidity (65% RH) controls were engaged throughout the depressurization, although temperatures dropped to near 16 °C for a brief period. CO2 and O2 were not detectable at the low pressure, suggesting that most of the 1.5 kPa atmosphere consisted of water vapor. Following re-pressurization, plants were grown for another 7 days at the original pressures and then harvested. The lettuce, radish, and wheat plants showed no visible effects from the rapid decompression, and there were no differences in fresh or dry mass when compared to control plants maintained continuously at 33 or 98 kPa. But radish storage root fresh mass and lettuce head fresh and dry masses were less at 33 kPa compared to 98 kPa for both the controls and decompression treatment. The results suggest that plants are extremely resilient to rapid decompression, provided they do not freeze (from evaporative cooling) or desiccate. The water of the hydroponic system was below the boiling pressure during these tests and this may have protected the plants by preventing pressures from dropping below 1.5 kPa and maintaining humidity near 1.5 kPa. Further testing is needed to determine how long plants can withstand such low pressure, but the results suggest there are at least 30 min to respond to catastrophic pressure losses in a plant production chamber that might be used for life

  1. 29 CFR Appendix A to Subpart S of... - Decompression Tables

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... uniform rate from 4 pounds to 0-pound gage over a period of 40 minutes. Rate—0.10 pound per minute or 10.../pound Total time decompress minutes 14 1/2 1 14 4 2 0.20 6 2 4 0 4 1.00 6 1 1 14 4 2 0.20 6 2 4 0 4 1.00 6 11/2 1 14 4 2 0.20 6 2 4 0 4 1.00 6 2 1 14 4 2 0.20 6 2 4 0 4 1.00 6 3 1 14 4 2 0.20 6 2 4 0 4 1...

  2. Minimally invasive carpal tunnel decompression using the KnifeLight.

    PubMed

    Hwang, Peter Y K; Ho, Chi Long

    2007-02-01

    Carpal tunnel syndrome is a common condition causing hand pain, dysfunction, and paresthesia. Endoscopic carpal tunnel decompression offers many advantages compared with conventional open surgical decompression. However, it is equipment intensive and requires familiarity with endoscopic surgery. We review a minimally invasive technique to divide the flexor retinaculum by using a new instrument, the KnifeLight (Stryker, Kalamazoo, Michigan), which combines the advantages of the open and endoscopic methods, without the need for endoscopic set-up. Between July 2003 and April 2005, 44 consecutive patients (26 women [59%] and 18 men [36%]), with clinical signs and symptoms, as well as electrodiagnostic findings consistent with carpal tunnel syndrome, who did not respond to non-surgical treatment, underwent the new procedure. All patients were asked about scar hypertrophy, scar tenderness, and pillar pain. The Michigan Hand Outcomes Questionnaire (MHQ) was used to determine overall hand function, activities of daily living, work performance, pain, aesthetics, and satisfaction with hand function. Other preoperative testing included grip strength and lateral pinch strength. Grip strength was measured using the Jamar hand dynamometer (Asimov Engineering Co., Los Angeles, CA); lateral key pinch was measured using the Jamar hydraulic pinch gauge. Postoperative evaluations were scheduled at 2 weeks, 3 months, and 6 months after the procedure. A small 10-mm incision was made in the wrist crease and a small opening was made at the transverse carpal ligament. The KnifeLight tool was inserted, and the ligament was incised completely. Follow-up evaluations with use of quantitative measurements of grip strength, pinch strength, and hand dexterity were performed at 2 weeks, 3 months, and 6 months after surgery. Fifty procedures were performed on 22 left hands (44%) and 28 right hands (56%). There were no complications related to the approach. All patients were able to use their hands

  3. Results of decompression surgery for pain in chronic pancreatitis

    PubMed Central

    Terrace, J.D.; Paterson, H.M.; Garden, O.J.; Parks, R.W.

    2007-01-01

    Introduction. A vast majority of patients with chronic pancreatitis require regular opiate/opioid analgesia and recurrent hospital admission for pain. However, the role and timing of operative strategies for pain in chronic pancreatitis is controversial. This study hypothesized that pancreatic decompression surgery reduces analgesia requirement and hospital readmission for pain in selected patients. Patients and methods. This was a retrospective review of patients undergoing longitudinal pancreatico-jejunostomy (LPJ), with or without coring of the pancreatic head (Frey's procedure), between 1995 and 2007 in a single UK centre. Surgery was performed for chronic pain with clinical/radiological evidence of chronic pancreatitis amenable to decompression/head coring. Results. Fifty patients were identified. Thirty-six were male with a median age of 46 years and median follow-up of 30 months. Twenty-eight underwent LPJ and 22underwent Frey's procedure. No significant difference in reduction of analgesia requirement (71% vs 64%, p=0.761) or hospital readmission for pain (21% vs 23%, p=1.000) was observed when comparing LPJ and Frey's procedure. Patients were significantly more likely to be pain-free following surgery if they required non-opiate rather than opiate analgesia preoperatively (75% vs 19%, p=0.0002). Fewer patients required subsequent hospital readmission for pain if taking non-opiate rather than opiate analgesia preoperatively (12.5% vs 31%, p=0.175). Conclusions. In selected patients, LPJ and Frey's procedure have equivalent benefit in short-term pain reduction. Patients should be selected for surgery before the commencement of opiate analgesia. PMID:18345310

  4. The Mars Project: Avoiding Decompression Sickness on a Distant Planet

    NASA Astrophysics Data System (ADS)

    Conkin, Johnny

    2000-05-01

    A cost-effective approach for Mars exploration is to use available resources, such as water and atmospheric gases. Nitrogen (N2) and argon (Ar) are available and could form the inert gas component of a habitat atmosphere at 8.0, 9.0, or 10.0 pounds per square inch (psia). The habitat and space suit are designed as an integrated system: a comfortable living environment about 85% of the time and a safe working environment about 15% of the time. A goal is to provide a system that permits unrestricted exploration of Mars, but the risk of decompression sickness (DCS) during the extravehicular activity in a 3.75-psia suit, after exposure to any of the three habitat conditions, may limit unrestricted exploration. I evaluate here the risk of DCS since a significant proportion of a trinary breathing gas in the habitat might contain Ar. I draw on past experience and published information to extrapolate into untested, multivariable conditions to evaluate risk. A rigorous assessment of risk as a probability of DCS for each habitat condition is not yet possible. Based on many assumptions about Ar in hypobaric decompressions, I conclude that the presence of Ar significantly increases the risk of DCS. The risk is significant even with the best habitat option: 2.56 psia oxygen, 3.41 psia N2, and 2.20 psia Ar. Several hours of prebreathing 100% 02, a higher suit pressure, or a combination of other important variables such as limited exposure time on the surface or exercise during prebreathe would be necessary to reduce the risk of DCS to an acceptable level. The acceptable level for DCS risk on Mars has not yet been determined. Mars is a great distance from Earth and therefore from primary medical care. The acceptable risk would necessarily be defined by the capability to treat DCS in the Rover vehicle, in the habitat, or both.

  5. 2014 Decompression Sickness/Extravehicular Activity Risks Standing Review Panel

    NASA Technical Reports Server (NTRS)

    Steinberg, Susan; Mahon, Richard; Klaus, David; Neuman, Tom; Pilmanis, Andrew; Regis, David

    2014-01-01

    The 2014 Decompression Sickness (DCS)/Extravehicular Activity (EVA) Risks Standing Review Panel (from here on referred to as the SRP) met for a site visit in Houston, TX on November 4 - 5, 2014. The SRP reviewed the Research Plans for The Risk of Decompression Sickness and the Risk of Injury and Compromised Performance due to EVA Operations, as well as the Evidence Reports for both of these Risks. The SRP found that the NASA DCS/EVA team did an excellent job of presenting their research plans. The SRP considers it critical that NASA proceeds with the high priority tasks identified in this report (DCS1, DCS3, DCS5). The highest priority is to determine the acceptable DCS and hypoxia risk associated with the planned human exploration beyond low Earth orbit. The risk of DCS is highly dependent upon the pressure within the exploration vehicle. If slightly more hypoxia is permitted then (even with the same percentage of oxygen) the pressure within the exploration vehicle can be lowered thus further mitigating the risk of DCS. The second highest priority is to test and validate the recommended 8.2psi/34% O2 atmosphere. Development of procedures and equipment for human exploration missions are very limited until the results of this testing are completed. The SRP also suggests that DCS7 be separated into two Gaps. Gap DCS7 should deal with DCS treatment while a new Gap should be created to deal with the long-term effects of DCS. The SRP also encourages NASA to increase collaboration with other organizations and pool resources where possible. The current NASA DCS/EVA team has the extensive expertise and a wealth of knowledge in this area. The SRP suggests that increased manpower for this team would be highly productive.

  6. Preconditioning to Reduce Decompression Stress in Scuba Divers.

    PubMed

    Germonpré, Peter; Balestra, Costantino

    2017-02-01

    Using ultrasound imaging, vascular gas emboli (VGE) are observed after asymptomatic scuba dives and are considered a key element in the potential development of decompression sickness (DCS). Diving is also accompanied with vascular dysfunction, as measured by flow-mediated dilation (FMD). Previous studies showed significant intersubject variability to VGE for the same diving exposure and demonstrated that VGE can be reduced with even a single pre-dive intervention. Several preconditioning methods have been reported recently, seemingly acting either on VGE quantity or on endothelial inflammatory markers. Nine male divers who consistently showed VGE postdive performed a standardized deep pool dive (33 m/108 ft, 20 min in 33°C water temperature) to investigate the effect of three different preconditioning interventions: heat exposure (a 30-min session of dry infrared sauna), whole-body vibration (a 30-min session on a vibration mattress), and dark chocolate ingestion (30 g of chocolate containing 86% cocoa). Dives were made one day per week and interventions were administered in a randomized order. These interventions were shown to selectively reduce VGE, FMD, or both compared to control dives. Vibration had an effect on VGE (39.54%, SEM 16.3%) but not on FMD postdive. Sauna had effects on both parameters (VGE: 26.64%, SEM 10.4%; FMD: 102.7%, SEM 2.1%), whereas chocolate only improved FMD (102.5%, SEM 1.7%). This experiment, which had the same subjects perform all control and preconditioning dives in wet but completely standardized diving conditions, demonstrates that endothelial dysfunction appears to not be solely related to VGE.Germonpré P, Balestra C. Preconditioning to reduce decompression stress in scuba divers. Aerosp Med Hum Perform. 2017; 88(2):114-120.

  7. The Mars Project: Avoiding Decompression Sickness on a Distant Planet

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny

    2000-01-01

    A cost-effective approach for Mars exploration is to use available resources, such as water and atmospheric gases. Nitrogen (N2) and argon (Ar) are available and could form the inert gas component of a habitat atmosphere at 8.0, 9.0, or 10.0 pounds per square inch (psia). The habitat and space suit are designed as an integrated system: a comfortable living environment about 85% of the time and a safe working environment about 15% of the time. A goal is to provide a system that permits unrestricted exploration of Mars, but the risk of decompression sickness (DCS) during the extravehicular activity in a 3.75-psia suit, after exposure to any of the three habitat conditions, may limit unrestricted exploration. I evaluate here the risk of DCS since a significant proportion of a trinary breathing gas in the habitat might contain Ar. I draw on past experience and published information to extrapolate into untested, multivariable conditions to evaluate risk. A rigorous assessment of risk as a probability of DCS for each habitat condition is not yet possible. Based on many assumptions about Ar in hypobaric decompressions, I conclude that the presence of Ar significantly increases the risk of DCS. The risk is significant even with the best habitat option: 2.56 psia oxygen, 3.41 psia N2, and 2.20 psia Ar. Several hours of prebreathing 100% 02, a higher suit pressure, or a combination of other important variables such as limited exposure time on the surface or exercise during prebreathe would be necessary to reduce the risk of DCS to an acceptable level. The acceptable level for DCS risk on Mars has not yet been determined. Mars is a great distance from Earth and therefore from primary medical care. The acceptable risk would necessarily be defined by the capability to treat DCS in the Rover vehicle, in the habitat, or both.

  8. A no-decompression air dive and ultrasound lung comets.

    PubMed

    Dujic, Zeljko; Marinovic, Jasna; Obad, Ante; Ivancev, Vladimir; Breskovic, Toni; Jovovic, Pavle; Ljubkovic, Marko

    2011-01-01

    Increased accumulation of extravascular lung water after repetitive deep trimix dives was recently reported. This effect was evident 40 min post-dive, but in subsequent studies most signs of this lung congestion were not evident 2-3 h post-dive, indicating no major negative effects on respiratory gas exchange following deep dives. Whether this response is unique for trimix dives or also occurs in more frequent air dives is presently unknown. A single no-decompression field dive to 33 m with 20 min bottom time was performed by 12 male divers. Multiple ultrasound lung comets (ULC), bubble grade (BG), and single-breath lung diffusing capacity (DLCO) measurements were made before and up to 120 min after the dive. Median BG was rather high with maximal values observed at 40 min post-dive [median 4 (4-4)]. Arterialization of bubbles from the venous side was observed only in one diver lasting up to 60 min post-dive. Despite high BG, no DCS symptoms were noted. DLCO and ULC were unchanged after the dive at any time point (DLCO(corr) was 33.6 +/- 1.9 ml x min(-1) mmHg(-1) pre-dive, 32.7 +/- 3.8 ml x min(-1) x mmHg(-1) at 60 min post-dive, and 33.2 +/- 5.3 ml x min(-1) x mmHg(-1) at 120 min post-dive; ULC count was 4.1 +/- 1.9 pre-dive, 4.9 +/- 3.3 at 20 min post-dive, and 3.3 +/- 1.9 at 60 min post-dive. These preliminary findings show no evidence of increased accumulation of extravascular lung water in male divers after a single no-decompression air dive at the limits of accepted Norwegian diving tables.

  9. The Extended Oxygen Window Concept for Programming Saturation Decompressions Using Air and Nitrox

    PubMed Central

    Kot, Jacek; Sicko, Zdzislaw

    2015-01-01

    Saturation decompression is a physiological process of transition from one steady state, full saturation with inert gas at pressure, to another one: standard conditions at surface. It is defined by the borderline condition for time spent at a particular depth (pressure) and inert gas in the breathing mixture (nitrogen, helium). It is a delicate and long lasting process during which single milliliters of inert gas are eliminated every minute, and any disturbance can lead to the creation of gas bubbles leading to decompression sickness (DCS). Most operational procedures rely on experimentally found parameters describing a continuous slow decompression rate. In Poland, the system for programming of continuous decompression after saturation with compressed air and nitrox has been developed as based on the concept of the Extended Oxygen Window (EOW). EOW mainly depends on the physiology of the metabolic oxygen window—also called inherent unsaturation or partial pressure vacancy—but also on metabolism of carbon dioxide, the existence of water vapor, as well as tissue tension. Initially, ambient pressure can be reduced at a higher rate allowing the elimination of inert gas from faster compartments using the EOW concept, and maximum outflow of nitrogen. Then, keeping a driving force for long decompression not exceeding the EOW allows optimal elimination of nitrogen from the limiting compartment with half-time of 360 min. The model has been theoretically verified through its application for estimation of risk of decompression sickness in published systems of air and nitrox saturation decompressions, where DCS cases were observed. Clear dose-reaction relation exists, and this confirms that any supersaturation over the EOW creates a risk for DCS. Using the concept of the EOW, 76 man-decompressions were conducted after air and nitrox saturations in depth range between 18 and 45 meters with no single case of DCS. In summary, the EOW concept describes physiology of

  10. Upper extremity palsy following cervical decompression surgery results from a transient spinal cord lesion.

    PubMed

    Hasegawa, Kazuhiro; Homma, Takao; Chiba, Yoshikazu

    2007-03-15

    Retrospective analysis. To test the hypothesis that spinal cord lesions cause postoperative upper extremity palsy. Postoperative paresis, so-called C5 palsy, of the upper extremities is a common complication of cervical surgery. Although there are several hypotheses regarding the etiology of C5 palsy, convincing evidence with a sufficient study population, statistical analysis, and clear radiographic images illustrating the nerve root impediment has not been presented. We hypothesized that the palsy is caused by spinal cord damage following the surgical decompression performed for chronic compressive cervical disorders. The study population comprised 857 patients with chronic cervical cord compressive lesions who underwent decompression surgery. Anterior decompression and fusion was performed in 424 cases, laminoplasty in 345 cases, and laminectomy in 88 cases. Neurologic characteristics of patients with postoperative upper extremity palsy were investigated. Relationships between the palsy, and patient sex, age, diagnosis, procedure, area of decompression, and preoperative Japanese Orthopaedic Association score were evaluated with a risk factor analysis. Radiographic examinations were performed for all palsy cases. Postoperative upper extremity palsy occurred in 49 cases (5.7%). The common features of the palsy cases were solely chronic compressive spinal cord disorders and decompression surgery to the cord. There was no difference in the incidence of palsy among the procedures. Cervical segments beyond C5 were often disturbed with frequent multiple segment involvement. There was a tendency for spontaneous improvement of the palsy. Age, decompression area (anterior procedure), and diagnosis (ossification of the posterior longitudinal ligament) are the highest risk factors of the palsy. The results of the present study support our hypothesis that the etiology of the palsy is a transient disturbance of the spinal cord following a decompression procedure. It appears

  11. Gas embolization of the liver in a rat model of rapid decompression.

    PubMed

    L'Abbate, Antonio; Kusmic, Claudia; Matteucci, Marco; Pelosi, Gualtiero; Navari, Alessandro; Pagliazzo, Antonino; Longobardi, Pasquale; Bedini, Remo

    2010-08-01

    Occurrence of liver gas embolism after rapid decompression was assessed in 31 female rats that were decompressed in 12 min after 42 min of compression at 7 ATA (protocol A). Sixteen rats died after decompression (group I). Of the surviving rats, seven were killed at 3 h (group II), and eight at 24 h (group III). In group I, bubbles were visible in the right heart, aortic arch, liver, and mesenteric veins and on the intestinal surface. Histology showed perilobular microcavities in sinusoids, interstitial spaces, and hepatocytes. In group II, liver gas was visible in two rats. Perilobular vacuolization and significant plasma aminotransferase increase were present. In group III, liver edema was evident at gross examination in all cases. Histology showed perilobular cell swelling, vacuolization, or hydropic degeneration. Compared with basal, enzymatic markers of liver damage increased significantly. An additional 14 rats were decompressed twice (protocol B). Overall mortality was 93%. In addition to diffuse hydropic degeneration, centrilobular necrosis was frequently observed after the second decompression. Additionally, 10 rats were exposed to three decompression sessions (protocol C) with doubled decompression time. Their mortality rate decreased to 20%, but enzymatic markers still increased in surviving rats compared with predecompression, and perilobular cell swelling and vacuolization were present in five rats. Study challenges were 1) liver is not part of the pathophysiology of decompression in the existing paradigm, and 2) although significant cellular necrosis was observed in few animals, zonal or diffuse hepatocellular damage associated with liver dysfunction was frequently demonstrated. Liver participation in human decompression sickness should be looked for and clinically evaluated.

  12. A current review of core decompression in the treatment of osteonecrosis of the femoral head.

    PubMed

    Pierce, Todd P; Jauregui, Julio J; Elmallah, Randa K; Lavernia, Carlos J; Mont, Michael A; Nace, James

    2015-09-01

    The review describes the following: (1) how traditional core decompression is performed, (2) adjunctive treatments, (3) multiple percutaneous drilling technique, and (4) the overall outcomes of these procedures. Core decompression has optimal outcomes when used in the earliest, precollapse disease stages. More recent studies have reported excellent outcomes with percutaneous drilling. Furthermore, adjunct treatment methods combining core decompression with growth factors, bone morphogenic proteins, stem cells, and bone grafting have demonstrated positive results; however, larger randomized trial is needed to evaluate their overall efficacy.

  13. Unusual Clinical Presentation and Role of Decompressive Craniectomy in Herpes Simplex Encephalitis.

    PubMed

    Singhi, Pratibha; Saini, Arushi Gahlot; Sahu, Jitendra Kumar; Kumar, Nuthan; Vyas, Sameer; Vasishta, Rakesh Kumar; Aggarwal, Ashish

    2015-08-01

    Decompressive craniectomy in pediatric central nervous infections with refractory intracranial hypertension is less commonly practiced. We describe improved outcome of decompressive craniectomy in a 7-year-old boy with severe herpes simplex encephalitis and medically refractory intracranial hypertension, along with a brief review of the literature. Timely recognition of refractory intracranial hypertension and surgical decompression in children with herpes simplex encephalitis can be life-saving. Additionally, strokelike atypical presentations are being increasingly recognized in children with herpes simplex encephalitis and should not take one away from the underlying herpes simplex encephalitis. © The Author(s) 2014.

  14. Retinal microvascular changes and subsequent vascular events after ischemic stroke.

    PubMed

    De Silva, D A; Manzano, J J F; Liu, E Y; Woon, F-P; Wong, W-X; Chang, H-M; Chen, C; Lindley, R I; Wang, J J; Mitchell, P; Wong, T-Y; Wong, M-C

    2011-08-30

    Retinal microvasculature changes are associated with vascular events including stroke in healthy populations. It is not known whether retinal microvascular changes predict recurrent vascular events after ischemic stroke. We examined the relationship between retinal microvascular signs and subsequent vascular events in a prospective cohort of 652 acute ischemic stroke patients admitted to a tertiary hospital in Singapore from 2005 to 2007. Retinal photographs taken within 1 week of stroke onset were assessed in a masked manner for quantitative and qualitative measures. Follow-up data over 2-4 years were obtained by standardized telephone interview and then were verified from medical records. Predictors of recurrent vascular events (cerebrovascular, coronary, vascular death, and composite vascular events) were determined using Cox regression models. Follow-up data over a median of 29 months were obtained for 89% (652 patients) of the cohort. After adjustment for covariates including traditional risk factors and index stroke etiology, patients with severe arteriovenous nicking (AVN) were more likely to have a recurrent cerebrovascular event (hazard ratio [HR] 2.28, 95% confidence interval [CI] 1.20-4.33) compared with those without AVN. Patients with severe focal arteriolar narrowing (FAN) were more likely to have a recurrent cerebrovascular event (HR 2.75, 95% CI 1.14-6.63) or subsequent composite vascular event (HR 2.77, 95% CI 1.31-5.86) compared to those without FAN. Retinal microvascular changes predicted subsequent vascular events after ischemic stroke, independent of traditional risk factors and stroke subtype. Thus, retinal imaging has a potential role in predicting the risk of recurrent vascular events after ischemic stroke and in understanding novel vascular risk factors.

  15. Classification and Microvascular Flap Selection for Anterior Cranial Fossa Reconstruction.

    PubMed

    Vargo, James D; Przylecki, Wojciech; Camarata, Paul J; Andrews, Brian T

    2018-05-18

    Microvascular reconstruction of the anterior cranial fossa (ACF) creates difficult challenges. Reconstructive goals and flap selection vary based on the defect location within the ACF. This study evaluates the feasibility and reliability of free tissue transfer for salvage reconstruction of low, middle, and high ACF defects.  A retrospective review was performed. Reconstructions were anatomically classified as low (anterior skull base), middle (frontal bar/sinus), and high (frontal bone/soft tissue). Subjects were evaluated based on pathologic indication and goal, type of flap used, and complications observed.  Eleven flaps in 10 subjects were identified and anatomic sites included: low ( n  = 5), middle ( n  = 3), and high ( n  = 3). Eight of 11 reconstructions utilized osteocutaneous flaps including the osteocutaneous radial forearm free flap (OCRFFF) ( n  = 7) and fibula ( n  = 1). Other reconstructions included a split calvarial graft wrapped within a temporoparietal fascia free flap ( n  = 1), latissimus myocutaneous flap ( n  = 1), and rectus abdominis myofascial flap ( n  = 1). All 11 flaps were successful without microvascular compromise. No complications were observed in the high and middle ACF defect groups. Two of five flaps in the low defect group using OCRFFF flaps failed to achieve surgical goals despite demonstrating healthy flaps upon re-exploration. Complications included persistent cerebrospinal fluid leak ( n  = 1) and pneumocephalus ( n  = 1), requiring flap repositioning in one subject and a second microvascular flap in the second subject to achieve surgical goals.  In our experience, osteocutaneous flaps (especially the OCRFFF) are preferred for complete autologous reconstruction of high and middle ACF defects. Low skull base defects are more difficult to reconstruct, and consideration of free muscle flaps (no bone) should be weighed as an option in this anatomic area. Thieme Medical Publishers

  16. Partially degradable fibers and microvascular materials formed from the fibers

    SciTech Connect

    Dong, Hefei; Pety, Stephen J.; Sottos, Nancy R.

    A partially degradable polymeric fiber includes a thermally degradable polymeric core and a coating surrounding at least a portion of the core. The thermally degradable polymeric core includes a polymeric matrix including a poly(hydroxyalkanoate), and a metal selected from the group consisting of an alkali earth metal and a transition metal, in the core polymeric matrix. The concentration of the metal in the polymeric matrix is at least 0.1 wt %. The partially degradable polymeric fiber may be used to form a microvascular system containing one or more microfluidic channels.

  17. Quantifying Therapeutic and Diagnostic Efficacy in 2D Microvascular Images

    NASA Technical Reports Server (NTRS)

    Parsons-Wingerter, Patricia; Vickerman, Mary B.; Keith, Patricia A.

    2009-01-01

    VESGEN is a newly automated, user-interactive program that maps and quantifies the effects of vascular therapeutics and regulators on microvascular form and function. VESGEN analyzes two-dimensional, black and white vascular images by measuring important vessel morphology parameters. This software guides the user through each required step of the analysis process via a concise graphical user interface (GUI). Primary applications of the VESGEN code are 2D vascular images acquired as clinical diagnostic images of the human retina and as experimental studies of the effects of vascular regulators and therapeutics on vessel remodeling.

  18. Antiproliferative effect of elevated glucose in human microvascular endothelial cells

    NASA Technical Reports Server (NTRS)

    Kamal, K.; Du, W.; Mills, I.; Sumpio, B. E.

    1998-01-01

    Diabetic microangiopathy has been implicated as a fundamental feature of the pathological complications of diabetes including retinopathy, neuropathy, and diabetic foot ulceration. However, previous studies devoted to examining the deleterious effects of elevated glucose on the endothelium have been performed largely in primary cultured cells of macrovessel origin. Difficulty in the harvesting and maintenance of microvascular endothelial cells in culture have hindered the study of this relevant population. Therefore, the objective of this study was to characterize the effect of elevated glucose on the proliferation and involved signaling pathways of an immortalized human dermal microvascular endothelial cell line (HMEC-1) that possess similar characteristics to their in vivo counterparts. Human dermal microvascular endothelial cells (HMEC-1) were grown in the presence of normal (5 mM) or high D-glucose (20 mM) for 14 days. The proliferative response of HMEC-1 was compared under these conditions as well as the cAMP and PKC pathways by in vitro assays. Elevated glucose significantly inhibited (P < 0.05) HMEC-1 proliferation after 7, 10, and 14 days. This effect was not mimicked by 20 mM mannitol. The antiproliferative effect was more pronounced with longer exposure (1-14 days) to elevated glucose and was irreversible 4 days after a 10-day exposure. The antiproliferative effect was partially reversed in the presence of a PKA inhibitor, Rp-cAMP (10-50 microM), and/or a PKC inhibitor, Calphostin C (10 nM). HMEC-1 exposed to elevated glucose (20 mM) for 14 days caused an increase in cyclic AMP accumulation, PKA, and PKC activity but was not associated with the activation of downstream events such as CRE and AP-1 binding activity. These data support the hypothesis that HMEC-1 is a suitable model to study the deleterious effects of elevated glucose on microvascular endothelial cells. Continued studies with HMEC-1 may prove advantageous in delineation of the molecular

  19. Severe Hemifacial Spasm is a Predictor of Severe Indentation and Facial Palsy after Microdecompression Surgery.

    PubMed

    Na, Boo Suk; Cho, Jin Whan; Park, Kwan; Kwon, Soonwook; Kim, Ye Sel; Kim, Ji Sun; Youn, Jinyoung

    2018-04-27

    Hemifacial spasm (HFS) is mostly caused by the compression of the facial nerve by cerebral vessels, but the significance of spasm severity remains unclear. We investigated the clinical significance of spasm severity in patients with HFS who underwent microvascular decompression (MVD). We enrolled 636 patients with HFS who underwent MVD between May 2010 and December 2013 at Samsung Medical Center (SMC), Seoul, Korea. Subjects were divided into two groups based on spasm severity: severe (SMC grade 3 or 4) and mild (SMC grade 1 or 2). We compared demographic, clinical, and surgical data between these two groups. The severe-spasm group was older and had a longer disease duration at the time of MVD compared to the mild-spasm group. Additionally, hypertension and diabetes mellitus were more common in the severe-spasm group than in the mild-spasm group. Regarding surgical findings, there were more patients with multiple offending vessels and more-severe indentations in the severe-spasm group than in the mild-spasm group. Even though the surgical outcomes did not differ, the incidence of delayed facial palsy after MVD was higher in the severe-spasm group than in the mild-spasm group. Logistic regression analysis showed that severe-spasm was correlated with longer disease duration, hypertension, severe indentation, multiple offending vessels, and delayed facial palsy after MVD. Spasm severity does not predict surgical outcomes, but it can be used as a marker of pathologic compression in MVD for HFS, and be considered as a predictor of delayed facial palsy after MVD. Copyright © 2018 Korean Neurological Association.

  20. Pathophysiology of hypertension: interactions between macro and microvascular alterations through endothelial dysfunction.

    PubMed

    Yannoutsos, Alexandra; Levy, Bernard I; Safar, Michel E; Slama, Gerard; Blacher, Jacques

    2014-02-01

    Hypertension is a multifactorial systemic chronic disorder through functional and structural macrovascular and microvascular alterations. Macrovascular alterations are featured by arterial stiffening, disturbed wave reflection and altered central to peripheral pulse pressure amplification. Microvascular alterations, including altered wall-to-lumen ratio of larger arterioles, vasomotor tone abnormalities and network rarefaction, lead to disturbed tissue perfusion and susceptibility to ischemia. Central arterial stiffness and microvascular alterations are common denominators of organ damages. Vascular alterations are intercorrelated, amplifying the haemodynamic load and causing further damage in the arterial network. A plausible precursor role of vascular alterations in incident hypertension provides new insights for preventive and therapeutic strategies targeting macro and microvasculature. Cumulative metabolic burden and oxidative stress lead to chronic endothelial injury, promoting structural and functional vascular alterations, especially in the microvascular network. Pathophysiology of hypertension may then be revisited, based on both macrovascular and microvascular alterations, with a precursor role of endothelial dysfunction for the latter.

  1. Prevention of decompression sickness during extravehicular activity in space: a review.

    PubMed

    Tokumaru, O

    1997-12-01

    Extended and more frequent extravehicular activity (EVA) is planned in NASA's future space programs. The more EVAs are conducted, the higher the incidence of decompression sickness (DCS) that is anticipated. Since Japan is also promoting the Space Station Freedom project with NASA, DCS during EVA will be an inevitable complication. The author reviewed the pathophysiology of DCS and detailed four possible ways of preventing decompression sickness during EVA in space: (1) higher pressure suit technology; (2) preoxygenation/prebreathing; (3) staged decompression; and (4) habitat or vehicle pressurization. Among these measures, development of zero-prebreathe higher pressure suit technology seems most ideal, but because of economic and technical reasons and in cases of emergency, other methods must also be improved. Unsolved problems like repeated decompression or oxygen toxicity were also listed.

  2. Mechanisms for microvascular damage induced by ultrasound-activated microbubbles

    NASA Astrophysics Data System (ADS)

    Chen, Hong; Brayman, Andrew A.; Evan, Andrew P.; Matula, Thomas J.

    2012-10-01

    To provide insight into the mechanisms of microvascular damage induced by ultrasound-activated microbubbles, experimental studies were performed to correlate microvascular damage to the dynamics of bubble-vessel interactions. High-speed photomicrography was used to record single microbubbles interacting with microvessels in ex vivo tissue, under the exposure of short ultrasound pulses with a center frequency of 1 MHz and peak negative pressures (PNP) ranging from 0.8-4 MPa. Vascular damage associated with observed bubble-vessel interactions was either indicated directly by microbubble extravasation or examined by transmission electron microscopy (TEM) analyses. As observed previously, the high-speed images revealed that ultrasound-activated microbubbles could cause distention and invagination of adjacent vessel walls, and could form liquid jets in microvessels. Vessel distention, invagination, and liquid jets were associated with the damage of microvessels whose diameters were smaller than those of maximally expanded microbubbles. However, vessel invagination appeared to be the dominant mechanism for the damage of relative large microvessels.

  3. Mechanisms for microvascular damage induced by ultrasound-activated microbubbles

    SciTech Connect

    Chen Hong; Brayman, Andrew A.; Evan, Andrew P.

    To provide insight into the mechanisms of microvascular damage induced by ultrasound-activated microbubbles, experimental studies were performed to correlate microvascular damage to the dynamics of bubble-vessel interactions. High-speed photomicrography was used to record single microbubbles interacting with microvessels in ex vivo tissue, under the exposure of short ultrasound pulses with a center frequency of 1 MHz and peak negative pressures (PNP) ranging from 0.8-4 MPa. Vascular damage associated with observed bubble-vessel interactions was either indicated directly by microbubble extravasation or examined by transmission electron microscopy (TEM) analyses. As observed previously, the high-speed images revealed that ultrasound-activated microbubbles could cause distentionmore » and invagination of adjacent vessel walls, and could form liquid jets in microvessels. Vessel distention, invagination, and liquid jets were associated with the damage of microvessels whose diameters were smaller than those of maximally expanded microbubbles. However, vessel invagination appeared to be the dominant mechanism for the damage of relative large microvessels.« less

  4. Lymph microvascularization as a prognostic indicator in neuroblastoma.

    PubMed

    Tadeo, Irene; Gamero-Sandemetrio, Esther; Berbegall, Ana P; Gironella, Marta; Ritort, Félix; Cañete, Adela; Bueno, Gloria; Navarro, Samuel; Noguera, Rosa

    2018-05-25

    Neuroblastoma is the most common extra-cranial solid pediatric cancer and causes approximately 15% of all childhood deaths from cancer. Although lymphatic vasculature is a prerequisite for the maintenance of tissue fluid balance and immunity in the body, little is known about the relationship between lymphatic vascularization and prognosis in neuroblastoma. We used our previously-published custom-designed tool to close open-outline vessels and measure the density, size and shape of all lymphatic vessels and microvascular segments in 332 primary neuroblastoma contained in tissue microarrays. The results were correlated with clinical and biological features of known prognostic value and with risk of progression to establish histological lymphatic vascular patterns associated with unfavorable histology. A high proportion of irregular intermediate lymphatic capillaries and irregular small collector vessels were present in tumors from patients with metastatic stage, undifferentiating neuroblasts and/or classified in the high risk. In addition, a higher lymphatic microvascularization density was found to be predictive of overall survival. Our findings show the crucial role of lymphatic vascularization in metastatic development and maintenance of tumor tissue homeostasis. These patterns may therefore help to indicate more accurate pre-treatment risk stratification and could provide candidate targets for novel therapies.

  5. Albumin microvascular leakage in brains with diabetes mellitus.

    PubMed

    Fujihara, Ryuji; Chiba, Yoichi; Nakagawa, Toshitaka; Nishi, Nozomu; Murakami, Ryuta; Matsumoto, Koichi; Kawauchi, Machi; Yamamoto, Tetsuji; Ueno, Masaki

    2016-09-01

    Their aim was to examine whether microvascular leakage of endogenous albumin, a representative marker for blood-brain barrier (BBB) damage, was induced in the periventricular area of diabetic db/db mice because periventricular white matter hyperintensity formation in magnetic resonance images was accelerating in elderly patients with diabetes mellitus. Using light and electron microscopes, and semi-quantitative analysis techniques, immunoreactivity of endogenous albumin, indicating vascular permeability, was examined in the periventricular area and spinal cord of db/db mice and db/+m control mice. Greater immunoreactivity of albumin was observed in the vessel wall of the periventricular area of db/db mice than in controls. Additionally, weak immunoreactivity was observed in the spinal cord of both db/db mice and controls. The number of gold particles, indicating immunoreactivity of albumin, in the perivascular area of db/db mice was significantly higher than that of control mice, but there was no significant difference in the number of particles in the spinal cord between db/db mice and controls. These findings suggest that albumin microvascular leakage, or BBB breakdown, is induced in the periventricular area of diabetic mice. Microsc. Res. Tech. 79:833-837, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  6. Changes in blood velocity following microvascular free tissue transfer.

    PubMed

    Hanasono, Matthew M; Ogunleye, Olubunmi; Yang, Justin S; Hartley, Craig J; Miller, Michael J

    2009-09-01

    Understanding how pedicle blood velocities change after free tissue transfer may enable microvascular surgeons to predict when thrombosis is most likely to occur. A 20-MHz Doppler probe was used to measure arterial and venous blood velocities prior to pedicle division and 20 minutes after anastomosis in 32 microvascular free flaps. An implantable Doppler probe was then used to measure arterial and venous blood velocities daily for 5 days. Peak arterial blood velocity averaged 30.6 cm/s prior to pedicle division and increased to 36.5 cm/s 20 minutes after anastomosis ( P < 0.05). Peak venous blood velocity averaged 7.6 cm/s prior to pedicle division and increased to 12.4 cm/s 20 minutes after anastomosis ( P < 0.05). Peak arterial blood velocities averaged 34.0, 37.7, 43.8, 37.9, 37.6 cm/s on postoperative days (PODs) 1 through 5, respectively. Peak venous blood velocities averaged 11.9, 14.5, 18.2, 16.8, 17.7 cm/s on PODs 1 through 5, respectively. The peak arterial blood velocity on POD 3, and peak venous blood velocities on PODs 2, 3, and 5 were significantly higher than 20 minutes after anastomosis ( P < 0.05). Arterial and venous blood velocities increase for the first 3 postoperative days, potentially contributing to the declining risk for pedicle thrombosis during this time period.

  7. Microvascular responsiveness in obesity: implications for therapeutic intervention

    PubMed Central

    Bagi, Zsolt; Feher, Attila; Cassuto, James

    2012-01-01

    Obesity has detrimental effects on the microcirculation. Functional changes in microvascular responsiveness may increase the risk of developing cardiovascular complications in obese patients. Emerging evidence indicates that selective therapeutic targeting of the microvessels may prevent life-threatening obesity-related vascular complications, such as ischaemic heart disease, heart failure and hypertension. It is also plausible that alterations in adipose tissue microcirculation contribute to the development of obesity. Therefore, targeting adipose tissue arterioles could represent a novel approach to reducing obesity. This review aims to examine recent studies that have been focused on vasomotor dysfunction of resistance arteries in obese humans and animal models of obesity. Particularly, findings in coronary resistance arteries are contrasted to those obtained in other vascular beds. We provide examples of therapeutic attempts, such as use of statins, ACE inhibitors and insulin sensitizers to prevent obesity-related microvascular complications. We further identify some of the important challenges and opportunities going forward. LINKED ARTICLES This article is part of a themed section on Fat and Vascular Responsiveness. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-3 PMID:21797844

  8. Microvascular oxygen consumption during sickle cell pain crisis.

    PubMed

    Rowley, Carol A; Ikeda, Allison K; Seidel, Miles; Anaebere, Tiffany C; Antalek, Matthew D; Seamon, Catherine; Conrey, Anna K; Mendelsohn, Laurel; Nichols, James; Gorbach, Alexander M; Kato, Gregory J; Ackerman, Hans

    2014-05-15

    Sickle cell disease is an inherited blood disorder characterized by chronic hemolytic anemia and episodic vaso-occlusive pain crises. Vaso-occlusion occurs when deoxygenated hemoglobin S polymerizes and erythrocytes sickle and adhere in the microvasculature, a process dependent on the concentration of hemoglobin S and the rate of deoxygenation, among other factors. We measured oxygen consumption in the thenar eminence during brachial artery occlusion in sickle cell patients and healthy individuals. Microvascular oxygen consumption was greater in sickle cell patients than in healthy individuals (median [interquartile range]; sickle cell: 0.91 [0.75-1.07] vs healthy: 0.75 [0.62-0.94] -ΔHbO2/min, P < .05) and was elevated further during acute pain crisis (crisis: 1.10 [0.78-1.30] vs recovered: 0.88 [0.76-1.03] -ΔHbO2/min, P < .05). Increased microvascular oxygen consumption during pain crisis could affect the local oxygen saturation of hemoglobin when oxygen delivery is limiting. Identifying the mechanisms of elevated oxygen consumption during pain crisis might lead to the development of new therapeutic interventions. This trial was registered at www.clinicaltrials.gov as #NCT01568710.

  9. Mitral annular calcification associated with impaired coronary microvascular function.

    PubMed

    Bozbas, Huseyin; Pirat, Bahar; Yildirir, Aylin; Simşek, Vahide; Sade, Elif; Altin, Cihan; Muderrisoglu, Haldun

    2008-05-01

    Mitral annular calcification (MAC) has been shown to be associated with atherosclerosis, and is a predictor of cardiovascular events. Coronary flow reserve (CFR) determined by transthoracic echocardiography has been introduced as a reliable indicator for coronary microvascular function. In this study we sought to investigate CFR in patients with and without MAC. Seventy patients (mean age, 68.2+/-6.6 years) who were free of coronary artery disease or diabetes mellitus were involved; 35 patients with MAC constituted the experimental group while 35 patients without MAC served as controls. Using transthoracic Doppler echocardiography coronary peak flow velocities were measured at baseline and after dipyridamole infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak flow velocities. The clinical and demographic characteristics including age, sex, and traditional coronary risk factors did not differ between the groups (P>.05). The mean value of CFR was significantly lower in participants with mitral annular calcification than it was in controls (2.25+/-0.41 vs. 2.64+/-0.57; P<.0001). Multivariable regression analysis identified MAC (beta=-0.40, P=.004), smoking (beta=-0.36, P=.007), and C-reactive protein levels (beta=-0.28, P=.04) as the independent variables significantly associated with CFR. Our results demonstrate that CFR is impaired in patients with mitral annular calcification suggesting that coronary microvascular-endothelial dysfunction, an early finding of atherosclerosis, is present in these patients.

  10. Critical Appraisal on Orbital Decompression for Thyroid Eye Disease: A Systematic Review and Literature Search.

    PubMed

    Boboridis, Konstadinos G; Uddin, Jimmy; Mikropoulos, Dimitrios G; Bunce, Catey; Mangouritsas, George; Voudouragkaki, Irini C; Konstas, Anastasios G P

    2015-07-01

    Orbital decompression is the indicated procedure for addressing exophthalmos and compressive optic neuropathy in thyroid eye disease. There are an abundance of techniques for removal of orbital bone, fat, or a combination published in the scientific literature. The relative efficacy and complications of these interventions in relation to the specific indications remain as yet undocumented. We performed a systematic review of the current published evidence for the effectiveness of orbital decompression, possible complications, and impact on quality of life. We searched the current databases for medical literature and controlled trials, oculoplastic textbooks, and conference proceedings to identify relevant data up to February 2015. We included randomized controlled trials (RCTs) comparing two or more interventions for orbital decompression. We identified only two eligible RCTs for inclusion in the review. As a result of the significant variability between studies on decompression, i.e., methodology and outcome measures, we did not perform a meta-analysis. One study suggests that the transantral approach and endonasal technique had similar effects in reducing exophthalmos but the latter is safer. The second study provides evidence that intravenous steroids may be superior to primary surgical decompression in the management of compressive optic neuropathy requiring less secondary surgical procedures. Most of the published literature on orbital decompression consists of retrospective, uncontrolled trials. There is evidence from those studies that removal of the medial and lateral wall (balanced) and the deep lateral wall decompression, with or without fat removal, may be the most effective surgical methods with only few complications. There is a clear unmet need for controlled trials evaluating the different techniques for orbital decompression. Ideally, future studies should address the effectiveness, possible complications, quality of life, and cost of each

  11. Alternative technique in atypical spinal decompression: the use of the ultrasonic scalpel in paediatric achondroplasia

    PubMed Central

    Woodacre, Timothy; Sewell, Matthew; Clarke, Andrew J; Hutton, Mike

    2016-01-01

    Spinal stenosis can be a very disabling condition. Surgical decompression carries a risk of dural tear and neural injury, which is increased in patients with severe stenosis or an atypical anatomy. We present an unusual case of symptomatic stenosis secondary to achondroplasia presenting in a paediatric patient, and highlight a new surgical technique used to minimise the risk of dural and neural injury during decompression. PMID:27288205

  12. Bilateral Ocular Decompression Retinopathy after Ahmed Valve Implantation for Uveitic Glaucoma.

    PubMed

    Flores-Preciado, Javier; Ancona-Lezama, David Arturo; Valdés-Lara, Carlos Andrés; Díez-Cattini, Gian Franco; Coloma-González, Itziar

    2016-01-01

    We report the case of a 29-year-old man who underwent Ahmed valve implantation in both eyes as treatment for uveitic glaucoma, subsequently presenting with bilateral ocular decompression retinopathy in the postoperative period. Ocular decompression retinopathy is a rare complication of filtering surgery in patients with glaucoma; however, the course is benign in most cases, with spontaneous resolution of bleedings and improvement of visual acuity.

  13. Bilateral Ocular Decompression Retinopathy after Ahmed Valve Implantation for Uveitic Glaucoma

    PubMed Central

    Flores-Preciado, Javier; Ancona-Lezama, David Arturo; Valdés-Lara, Carlos Andrés; Díez-Cattini, Gian Franco; Coloma-González, Itziar

    2016-01-01

    Case Report We report the case of a 29-year-old man who underwent Ahmed valve implantation in both eyes as treatment for uveitic glaucoma, subsequently presenting with bilateral ocular decompression retinopathy in the postoperative period. Discussion Ocular decompression retinopathy is a rare complication of filtering surgery in patients with glaucoma; however, the course is benign in most cases, with spontaneous resolution of bleedings and improvement of visual acuity. PMID:27920718

  14. Predictors of surgical revision after in situ decompression of the ulnar nerve.

    PubMed

    Krogue, Justin D; Aleem, Alexander W; Osei, Daniel A; Goldfarb, Charles A; Calfee, Ryan P

    2015-04-01

    This study was performed to identify factors associated with the need for revision surgery after in situ decompression of the ulnar nerve for cubital tunnel syndrome. This case-control investigation examined all patients treated at one institution with open in situ decompression for cubital tunnel syndrome between 2006 and 2011. The case patients were 44 failed decompressions that required revision, and the controls were 79 randomly selected patients treated with a single operation. Demographic data and disease-specific data were extracted from the medical records. The rate of revision surgery after in situ decompression was determined from our 5-year experience. A multivariate logistic regression model was used based on univariate testing to determine predictors of revision cubital tunnel surgery. Revision surgery was required in 19% (44 of 231) of all in situ decompressions performed during the study period. Predictors of revision surgery included a history of elbow fracture or dislocation (odds ratio [OR], 7.1) and McGowan stage I disease (OR, 3.2). Concurrent surgery with in situ decompression was protective against revision surgery (OR, 0.19). The rate of revision cubital tunnel surgery after in situ nerve decompression should be weighed against the benefits of a less invasive procedure compared with transposition. When considering in situ ulnar nerve decompression, prior elbow fracture as well as patients requesting surgery for mild clinically graded disease should be viewed as risk factors for revision surgery. Patient factors often considered relevant to surgical outcomes, including age, sex, body mass index, tobacco use, and diabetes status, were not associated with a greater likelihood of revision cubital tunnel surgery. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  15. Navigation-guided optic canal decompression for traumatic optic neuropathy: Two case reports.

    PubMed

    Bhattacharjee, Kasturi; Serasiya, Samir; Kapoor, Deepika; Bhattacharjee, Harsha

    2018-06-01

    Two cases of traumatic optic neuropathy presented with profound loss of vision. Both cases received a course of intravenous corticosteroids elsewhere but did not improve. They underwent Navigation guided optic canal decompression via external transcaruncular approach, following which both cases showed visual improvement. Postoperative Visual Evoked Potential and optical coherence technology of Retinal nerve fibre layer showed improvement. These case reports emphasize on the role of stereotactic navigation technology for optic canal decompression in cases of traumatic optic neuropathy.

  16. Exploiting Aerobic Fitness To Reduce Risk Of Hypobaric Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Gernhardt, Michael L.; Wessel, James H., III

    2007-01-01

    Decompression sickness (DCS) is multivariable. But we hypothesize an aerobically fit person is less likely to experience hypobaric DCS than an unfit person given that fitness is exploited as part of the denitrogenation (prebreathe, PB) process prior to an altitude exposure. Aerobic fitness is peak oxygen uptake (VO2pk, ml/kg/min). METHODS: Treadmill or cycle protocols were used over 15 years to determine VO2pks. We evaluated dichotomous DCS outcome and venous gas emboli (VGE) outcome detected in the pulmonary artery with Doppler ultrasound associated with VO2pk for two classes of experiments: 1) those with no PB or PB under resting conditions prior to ascent in an altitude chamber, and 2) PB that included exercise for some part of the PB. There were 165 exposures (mean VO2pk 40.5 +/- 7.6 SD) with 25 cases of DCS in the first protocol class and 172 exposures (mean VO2pk 41.4 +/- 7.2 SD) with 25 cases of DCS in the second. Similar incidence of the DCS (15.2% vs. 14.5%) and VGE (45.5% vs. 44.8%) between the two classes indicates that decompression stress was similar. The strength of association between outcome and VO2pk was evaluated using univariate logistic regression. RESULTS: An inverse relationship between the DCS outcome and VO2pk was evident, but the relationship was strongest when exercise was done as part of the PB (exercise PB, coef. = -0.058, p = 0.07; rest or no PB, coef. = -0.005, p = 0.86). There was no relationship between VGE outcome and VO2pk (exercise PB, coef. = -0.003, p = 0.89; rest or no PB, coef. = 0.014, p = 0.50). CONCLUSIONS: A significant change in probability of DCS was associated with fitness only when exercise was included in the denitrogenation process. We believe a fit person that exercises during PB efficiently eliminates dissolved nitrogen from tissues.

  17. Exploiting Aerobic Fitness to Reduce Risk of Hypobaric Decompression Sickness

    NASA Technical Reports Server (NTRS)

    Conkin, J.; Gernhardt, M. L.; Wessel, J. H.

    2007-01-01

    Decompression sickness (DCS) is multivariable. But we hypothesize an aerobically fit person is less likely to experience hypobaric DCS than an unfit person given that fitness is exploited as part of the denitrogenation (prebreathe, PB) process prior to an altitude exposure. Aerobic fitness is peak oxygen uptake (VO2pk, ml/kg/min). Treadmill or cycle protocols were used over 15 years to determine VO2pks. We evaluated dichotomous DCS outcome and venous gas emboli (VGE) outcome detected in the pulmonary artery with Doppler ultrasound associated with VO2pk for two classes of experiments: 1) those with no PB or PB under resting conditions prior to ascent in an altitude chamber, and 2) PB that included exercise for some part of the PB. There were 165 exposures (mean VO2pk 40.5 plus or minus 7.6 SD) with 25 cases of DCS in the first protocol class and 172 exposures (mean VO2pk 41.4 plus or minus 7.2 SD) with 25 cases of DCS in the second. Similar incidence of the DCS (15.2% vs. 14.5%) and VGE (45.5% vs. 44.8%) between the two classes indicates that decompression stress was similar. The strength of association between outcome and VO2pk was evaluated using univariate logistic regression. An inverse relationship between the DCS outcome and VO2pk was evident, but the relationship was strongest when exercise was done as part of the PB (exercise PB, coef. = -0.058, p = 0.07; rest or no PB, coef. = -0.005, p = 0.86). There was no relationship between VGE outcome and VO2pk (exercise PB, coef. = -0.003, p = 0.89; rest or no PB, coef. = 0.014, p = 0.50). A significant change in probability of DCS was associated with fitness only when exercise was included in the denitrogenation process. We believe a fit person that exercises during PB efficiently eliminates dissolved nitrogen from tissues.

  18. Potential Fifty Percent Reduction in Saturation Diving Decompression Time Using a Combination of Intermittent Recompression and Exercise

    NASA Technical Reports Server (NTRS)

    Gernhardt, Michael I.; Abercromby, Andrew; Conklin, Johnny

    2007-01-01

    Conventional saturation decompression protocols use linear decompression rates that become progressively slower at shallower depths, consistent with free gas phase control vs. dissolved gas elimination kinetics. If decompression is limited by control of free gas phase, linear decompression is an inefficient strategy. The NASA prebreathe reduction program demonstrated that exercise during O2 prebreathe resulted in a 50% reduction (2 h vs. 4 h) in the saturation decompression time from 14.7 to 4.3 psi and a significant reduction in decompression sickness (DCS: 0 vs. 23.7%). Combining exercise with intermittent recompression, which controls gas phase growth and eliminates supersaturation before exercising, may enable more efficient saturation decompression schedules. A tissue bubble dynamics model (TBDM) was used in conjunction with a NASA exercise prebreathe model (NEPM) that relates tissue inert gas exchange rate constants to exercise (ml O2/kg-min), to develop a schedule for decompression from helium saturation at 400 fsw. The models provide significant prediction (p < 0.001) and goodness of fit with 430 cases of DCS in 6437 laboratory dives for TBDM (p = 0.77) and with 22 cases of DCS in 159 altitude exposures for NEPM (p = 0.70). The models have also been used operationally in over 25,000 dives (TBDM) and 40 spacewalks (NEPM). The standard U.S. Navy (USN) linear saturation decompression schedule from saturation at 400 fsw required 114.5 h with a maximum Bubble Growth Index (BGI(sub max)) of 17.5. Decompression using intermittent recompression combined with two 10 min exercise periods (75% VO2 (sub peak)) per day required 54.25 h (BGI(sub max): 14.7). Combined intermittent recompression and exercise resulted in a theoretical 53% (2.5 day) reduction in decompression time and theoretically lower DCS risk compared to the standard USN decompression schedule. These results warrant future decompression trials to evaluate the efficacy of this approach.

  19. Changes in optical coherence tomography measurements after orbital wall decompression in dysthyroid optic neuropathy.

    PubMed

    Park, Kyung-Ah; Kim, Yoon-Duck; Woo, Kyung In

    2018-06-01

    The purpose of our study was to assess changes in peripapillary retinal nerve fiber layer (RNFL) thickness after orbital wall decompression in eyes with dysthyroid optic neuropathy (DON). We analyzed peripapillary optical coherence tomography (OCT) images (Cirrus HD-OCT) from controls and patients with DON before and 1 and 6 months after orbital wall decompression. There was no significant difference in mean preoperative peripapillary retinal nerve fiber layer thickness between eyes with DON and controls. The superior and inferior peripapillary RNFL thickness decreased significantly 1 month after decompression surgery compared to preoperative values (p = 0.043 and p = 0.022, respectively). The global average, superior, temporal, and inferior peripapillary RNFL thickness decreased significantly 6 months after decompression surgery compared to preoperative values (p = 0.015, p = 0.028, p = 0.009, and p = 0.006, respectively). Patients with greater preoperative inferior peripapillary RNFL thickness tended to have better postoperative visual acuity at the last visit (p = 0.024, OR = 0.926). Our data revealed a significant decrease in peripapillary RNFL thickness postoperatively after orbital decompression surgery in patients with DON. We also found that greater preoperative inferior peripapillary RNFL thickness was associated with better visual outcomes. We suggest that RNFL thickness can be used as a prognostic factor for DON before decompression surgery.

  20. Decompression of keratocystic odontogenic tumors leading to increased fibrosis, but without any change in epithelial proliferation.

    PubMed

    Awni, Sarah; Conn, Brendan

    2017-06-01

    The aim of this study was to investigate whether decompression treatment induces changes in the histology or biologic behavior of keratocystic odontogenic tumor (KCOT). Seventeen patients with KCOT underwent decompression treatment with or without enucleation. Histologic evaluation and immunohistochemical expression of p53, Ki-67, and Bcl-2 were analyzed by using conventional microscopy. KCOT showed significantly increased fibrosis (P = .01) and a subjective reduction in mitotic activity (P = .03) after decompression. There were no statistically significant changes in the expression of proliferation markers. An increase in daughter-cysts or epithelial rests was seen after decompression (P = .04). Recurrence was noted in four of 16 cases, and expression of p53 was strongly correlated with prolonged duration of treatment (P = .01) and intense inflammatory changes (P = .02). Structural changes in the KCOT epithelium or capsule following decompression facilitate surgical removal of the tumor. There was no statistical evidence that decompression influences expression of proliferation markers in the lining, indicating that the potential for recurrence may not be restricted to the cellular level. The statistically significant increase of p53 expression with increased duration of treatment and increase of inflammation may also indicate the possibility of higher rates of recurrence with prolonged treatment and significant inflammatory changes. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  1. Core decompression of the equine navicular bone: an in vivo study in healthy horses.

    PubMed

    Jenner, Florien; Kirker-Head, Carl

    2011-02-01

    To determine the physiologic response of the equine navicular bone to core decompression surgery in healthy horses. Experimental in vivo study. Healthy adult horses (n=6). Core decompression was completed by creating three 2.5-mm-diameter drill channels into the navicular bone under arthroscopic control. The venous (P(V)), arterial (P(A)), articular (P(DIPJ)), and intraosseous pressures (IOP) were recorded before and after decompression drilling. Each IOP measurement consisted of a baseline (IOP(B)) and a stress test (intramedullary injection of saline solution, IOP(S)) recording. Lameness was assessed subjectively and using force plate gait analysis. Fluorochrome bone labeling was performed. Horses were euthanatized at 12 weeks. Navicular bone mineral density (BMD) was measured, and bone histology evaluated. Peak IOP (IOP(max)) after stress testing was significantly (P<.05) reduced immediately after core decompression; however, the magnitude of these effects was decreased at 3 and 6 weeks after decompression. A significant (P<.05) correlation existed between IOP(max) and BMD. No lameness was observed beyond the first week after surgery. Substantial remodeling and neovascularization was evident adjacent the surgery sites. Navicular bone core decompression surgery reduced IOP(max), and, with the exception of a mild short-lived lameness, caused no other adverse effects in healthy horses during the 12-week study period. © Copyright 2011 by The American College of Veterinary Surgeons.

  2. [Two-wall decompression without resection of the medial wall. Effect on squint angle].

    PubMed

    Bertelmann, E; Rüther, K

    2011-11-01

    Postoperative new onset diplopia can be a disadvantage for surgical orbital decompression in patients with exophthalmos in thyroid eye disease. The various modifications of decompression (number and combination of walls) differ in their influence on the postoperative squint angle. We report on postoperative diplopia in a modified 2 wall decompression strategy (lateral wall and floor). This study was a retrospective analysis of 36 consecutive 2-wall decompressions performed between 2006-2010 in 24 patients with 6 months of stable exophthalmos in thyroid eye disease after medical therapy and radiotherapy. The preoperative and postoperative squint angle in prism cover test (PCT), motility, induction of diplopia, reduction of exophthalmos, visual acuity and complications were evaluated. In all 36 decompressions the postoperative squint angle was equal to or less than before surgery. In 8 eyes additional squint surgery was performed. The mean reduction in exopthalmos was 4.3 mm. An adverse effect of decompression on the postoperative squint angle was not evident in this study. New induction of diplopia was not observed at all. One possible explanation is the preservation of the medial wall.

  3. Orbital fat decompression for thyroid eye disease: retrospective case review and criteria for optimal case selection.

    PubMed

    Prat, Marta Calsina; Braunstein, Alexandra L; Dagi Glass, Lora R; Kazim, Michael

    2015-01-01

    The purpose of this study is to identify the subgroups of thyroid eye disease (TED) patients most likely to benefit from orbital fat decompression. This retrospective study reviews 217 orbits of 109 patients who underwent orbital fat decompression for proptosis secondary to thyroid eye disease. Charts were reviewed for demographic, radiographic, clinical, and surgical data. Three groups of patients were defined for the purposes of statistical analysis: those with proptosis secondary to expansion of the fat compartment (group I), those with proptosis secondary to enlargement of the extraocular muscles (group II), and those with proptosis secondary to enlargement of both fat and muscle (group III). Groups I and II, and those patients with greater preoperative proptosis and those with a history of radiation therapy were most likely to benefit from orbital fat decompression. However, even those in group III or with lesser proptosis appreciated significant benefit. While orbital fat decompression can and, at times, should be combined with bone decompression to treat proptosis resulting from thyroid eye disease, orbital fat decompression alone is associated with lower rates of surgical morbidity, and is especially effective for group I and II patients, those with greater preoperative proptosis, and those with a history of radiation.

  4. Empirical models for use in designing decompression procedures for space operations

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Edwards, Benjamin F.; Waligora, James M.; Horrigan, David J., Jr.

    1987-01-01

    Empirical models for predicting the incidence of Type 1 altitude decompression sickness (DCS) and venous gas emboli (VGE) during space extravehicular activity (EVA), and for use in designing safe denitrogenation decompression procedures are developed. The models are parameterized using DCS and VGE incidence data from NASA and USAF manned altitude chamber decompression tests using 607 male and female subject tests. These models, and procedures for their use, consist of: (1) an exponential relaxation model and procedure for computing tissue nitrogen partial pressure resulting from a specified prebreathing and stepped decompression sequence; (2) a formula for calculating Tissue Ratio (TR), a tissue decompression stress index; (3) linear and Hill equation models for predicting the total incidence of VGE and DCS attendant with a particular TR; (4) graphs of cumulative DCS and VGE incidence (risk) versus EVA exposure time at any specified TR; and (5) two equations for calculating the average delay period for the initial detection of VGE or indication of Type 1 DCS in a group after a specific denitrogenation decompression procedure. Several examples of realistic EVA preparations are provided.

  5. Improved image decompression for reduced transform coding artifacts

    NASA Technical Reports Server (NTRS)

    Orourke, Thomas P.; Stevenson, Robert L.

    1994-01-01

    The perceived quality of images reconstructed from low bit rate compression is severely degraded by the appearance of transform coding artifacts. This paper proposes a method for producing higher quality reconstructed images based on a stochastic model for the image data. Quantization (scalar or vector) partitions the transform coefficient space and maps all points in a partition cell to a representative reconstruction point, usually taken as the centroid of the cell. The proposed image estimation technique selects the reconstruction point within the quantization partition cell which results in a reconstructed image which best fits a non-Gaussian Markov random field (MRF) image model. This approach results in a convex constrained optimization problem which can be solved iteratively. At each iteration, the gradient projection method is used to update the estimate based on the image model. In the transform domain, the resulting coefficient reconstruction points are projected to the particular quantization partition cells defined by the compressed image. Experimental results will be shown for images compressed using scalar quantization of block DCT and using vector quantization of subband wavelet transform. The proposed image decompression provides a reconstructed image with reduced visibility of transform coding artifacts and superior perceived quality.

  6. Type II decompression sickness in a hyperbaric inside attendant.

    PubMed

    Johnson-Arbor, Kelly

    2012-01-01

    Decompression sickness (DCS) of an inside attendant (IA) is rarely encountered in hyperbarics. This report describes an IA who developed Type II DCS after a routine hyperbaric exposure. A 50-year-old male complained of lower extremity weakness and paresthesias after serving as an IA during a hyperbaric treatment to 40 fsw (122.52 kPa). Within 10 minutes after the conclusion of the treatment, the IA experienced irritability and confusion, and was unable to walk. Physical examination revealed decreased sensation below the T7 level, and decreased strength in the lower extremities. Type II DCS was diagnosed, and the IA was recompressed to 60 fsw (183.78 kPa) on a U.S. Navy Treatment Table 6, which resulted in improvement of his symptoms. Transthoracic echocardiography with bubble study performed 16 months after the event demonstrated a large patent foramen ovale (PFO). Increased age, decreased physical fitness and the undiagnosed PFO may have predisposed this attendant to developing DCS. Although rare, DCS may occur in IAs. Routine monitoring and reporting of the long-term health of hyperbaric IAs should be considered by hyperbaric facilities and medical directors in order to further understand the characteristics of DCS and other hyperbaric-related conditions in these workers.

  7. Towards new paradigms for the treatment of hypobaric decompression sickness.

    PubMed

    Dart, T S; Butler, W

    1998-04-01

    Altitude induced (hypobaric) decompression sickness (DCS) has long been treated with ground level oxygen and U.S. Navy Treatment Tables 5 and 6. These treatment tables originate from surface excursion diving and, when implemented, require significant resource allocation. Although they are effective treatment regimens, these tables were not developed for treating hypobaric DCS which has an etiology similar to saturation diving DCS. In this review, different treatment options for hypobaric DCS are presented. These options include more aggressive use of ground level oxygen and treatment tables using a maximum pressure of 2 atmospheres (ATA). Specific attention is given to USAF Table VIII, an experimental hypobaric DCS treatment-table, and space suit overpressurization treatment. This paradigm shift for DCS treatment is based on a projected increase in hypobaric DCS treatment from exposure to low pressure during several operational conditions: cruise flight in the next generation aircraft (e.g., F-22); high altitude, unpressurized flight by special operations forces; and the extraordinary amount of extravehicular activity (EVA) required to construct the international space station. Anticipating the need to treat DCS encountered during these and other activities, it is proposed that 2 ATA or less hyperbaric oxygen (HBO) treatment conjoined with new collapsible chamber technology can be used to address these issues in a safe and cost effective fashion.

  8. Inner ear decompression sickness in compressed-air diving.

    PubMed

    Klingmann, Christoph

    2012-01-01

    Inner ear decompression sickness (IEDCS) has become more frequently reported in recreational diving. We examined 34 divers after IEDCS and analyzed their dive profiles, pattern of symptoms, time of symptom onset and the association with a right-to left shunt (r/l shunt). Four divers used mixed gas and were excluded from the analysis. Of the remaining 30 divers, 25 presented with isolated IEDCS alone, while five divers had additional skin and neurological symptoms. All divers presented with vertigo (100%), and 12 divers reported additional hearing loss (40%). All symptoms occurred within 120 minutes (median 30 minutes) of ascent. Twenty-two of 30 divers (73.3%) showed a r/l shunt. A possible explanation for the frequent association of a r/l shunt and the dominance of vestibular rather than cochlear symptoms could be attributed to the different blood supply of the inner ear structures and the different size of the labyrinthine compartments. The cochlea has a blood supply up to four times higher than the vestibular part of the inner ear, whereas the vestibular fluid space is 30% larger. The higher prevalence of symptoms referrable to the less well-perfused vestibular organ provides further evidence that persistent local inert gas supersaturation may cause growth of incoming arterial bubbles and may therefore be an important pathophysiological factor in IEDCS.

  9. Habitat Options to Protect Against Decompression Sickness on Mars

    NASA Astrophysics Data System (ADS)

    Conkin, J.

    2000-07-01

    Men and women are alive today, although perhaps still in diapers, who will explore the surface of Mars. Two achievable goals to enable this exploration are to use Martian resources, and to provide a safe means for unrestricted access to the surface. A cost-effective approach for Mars exploration is to use the available resources, such as water and atmospheric gases. Nitrogen (N2) and Argon (Ar) in a concentration ratio of 1.68/1.0 are available, and could form the inert gas component of a habitat atmosphere at 8.0, 9.0, or 10.0 pounds per square inch absolute (psia). The habitat and space suit must be designed as an integrated, complementary, system: a comfortable living environment about 85% of the time and a safe working environment about 15% of the time. A goal is to provide a system that permits unrestricted exploration of Mars. However the risk of decompression sickness (DCS) during the extravehicular activity (EVA) in a 3.75 psia suit after exposure to either of the three habitat conditions may limit unrestricted exploration.

  10. Window decompression in laser-heated MagLIF targets

    NASA Astrophysics Data System (ADS)

    Woodbury, Daniel; Peterson, Kyle; Sefkow, Adam

    2015-11-01

    The Magnetized Liner Inertial Fusion (MagLIF) concept requires pre-magnetized fuel to be pre-heated with a laser before undergoing compression by a thick solid liner. Recent experiments and simulations suggest that yield has been limited to date by poor laser preheat and laser-induced mix in the fuel region. In order to assess laser energy transmission through the pressure-holding window, as well as resultant mix, we modeled window disassembly under different conditions using 1D and 2D simulations in both Helios and HYDRA. We present results tracking energy absorption, time needed for decompression, risk of laser-plasma interaction (LPI) that may scatter laser light, and potential for mix from various window thicknesses, laser spot sizes and gas fill densities. These results indicate that using thinner windows (0.5-1 μm windows) and relatively large laser spot radii (600 μm and above) can avoid deleterious effects and improve coupling with the fuel. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the National Nuclear Security Administration under DE-AC04- 94AL85000.

  11. Hydrocephalus after decompressive craniectomy for malignant hemispheric cerebral infarction.

    PubMed

    Wang, Qiang-Ping; Ma, Jun-Peng; Zhou, Zhang-Ming; Yang, Min; You, Chao

    2016-08-01

    Several studies have investigated the incidence and risk factors of hydrocephalus after decompressive craniectomy (DC) for malignant hemispheric cerebral infarction. However, the results are controversial. Therefore, the following is a retrospective cohort study to determine the incidence and risk factors of hydrocephalus after DC for malignant hemispheric cerebral infarction. From January 2004 to June 2014, patients at two medical centres in south-west China, who underwent DC for malignant hemispheric cerebral infarction, were included. The patients' clinical and radiologic findings were retrospectively reviewed. A chi-square test, Mann-Whitney U-test and logistic regression model were used to identify the risk factors. A total of 128 patients were included in the study. The incidence of ventriculomegaly and shunt-dependent hydrocephalus were 42.2% (54/128) and 14.8% (19/128), respectively. Lower preoperative Glasgow Coma Scale (GCS) score and presence of subarachnoid haemorrhage (SAH) were factors significantly associated with the development of post-operative hydrocephalus after DC. Cerebral infarction patients receiving DC have a moderate tendency to suffer from post-operative hydrocephalus. A poor GCS score and the presence of SAH were significantly associated with the development of hydrocephalus after DC.

  12. Gas and particle motions in a rapidly decompressed flow

    NASA Astrophysics Data System (ADS)

    Johnson, Blair; Zunino, Heather; Adrian, Ronald; Clarke, Amanda

    2017-11-01

    To understand the behavior of a rapidly decompressed particle bed in response to a shock, an experimental study is performed in a cylindrical (D = 4.1 cm) glass vertical shock tube of a densely packed (ρ = 61%) particle bed. The bed is comprised of spherical glass particles, ranging from D50 = 44-297 μm between experiments. High-speed pressure sensors are incorporated to capture shock speeds and strengths. High-speed video and particle image velocimetry (PIV) measurements are collected to examine vertical and radial velocities of both the particles and gas to elucidate features of the shock wave and resultant expansion wave in the lateral center of the tube, away from boundaries. In addition to optically analyzing the front velocity of the rising particle bed, interaction between the particle and gas phases are investigated as the flow accelerates and the particle front becomes more dilute. Particle and gas interactions are also considered in exploring mechanisms through which turbulence develops in the flow. This work is supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science and Academic Alliance Program, under Contract No. DE-NA0002378.

  13. Uterine microvascular sensitivity to nanomaterial inhalation: An in vivo assessment

    SciTech Connect

    Stapleton, P.A.; McBride, C.R.; Yi, J.

    With the tremendous number and diverse applications of engineered nanomaterials incorporated in daily human activity, exposure can no longer be solely confined to occupational exposures of healthy male models. Cardiovascular and endothelial cell dysfunction have been established using in vitro and in situ preparations, but the translation to intact in vivo models is limited. Intravital microscopy has been used extensively to understand microvascular physiology while maintaining in vivo neurogenic, humoral, and myogenic control. However, a tissue specific model to assess the influences of nanomaterial exposure on female reproductive health has not been fully elucidated. Female Sprague Dawley (SD) rats weremore » exposed to nano-TiO{sub 2} aerosols (171 ± 6 nm, 10.1 ± 0.39 mg/m{sup 3}, 5 h) 24-hours prior to experimentation, leading to a calculated deposition of 42.0 ± 1.65 μg. After verifying estrus status, vital signs were monitored and the right horn of the uterus was exteriorized, gently secured over an optical pedestal, and enclosed in a warmed tissue bath using intravital microscopy techniques. After equilibration, significantly higher leukocyte-endothelium interactions were recorded in the exposed group. Arteriolar responsiveness was assessed using ionophoretically applied agents: muscarinic agonist acetylcholine (0.025 M; ACh; 20, 40, 100, and 200 nA), and nitric oxide donor sodium nitroprusside (0.05 M; SNP; 20, 40, and 100 nA), or adrenergic agonist phenylephrine (0.05 M; PE; 20, 40, and 100 nA) using glass micropipettes. Passive diameter was established by tissue superfusion with 10{sup −4} M adenosine. Similar to male counterparts, female SD rats present systemic microvascular dysfunction; however the ramifications associated with female health and reproduction have yet to be elucidated. - Highlights: • Female reproductive health associated with nanomaterial exposure is understudied. • We examined uterine microvascular alterations 24-hours

  14. Diagnostic Ultrasound High Mechanical Index Impulses Restore Microvascular Flow in Peripheral Arterial Thromboembolism.

    PubMed

    Porter, Thomas R; Radio, Stanley; Lof, John; Everbach, Carr; Powers, Jeffry E; Vignon, Francois; Shi, William T; Xie, Feng

    2016-07-01

    We sought to explore mechanistically how intermittent high-mechanical-index (MI) diagnostic ultrasound impulses restore microvascular flow. Thrombotic microvascular obstruction was created in the rat hindlimb muscle of 36 rats. A diagnostic transducer confirmed occlusion with low-MI imaging during an intravenous microbubble infusion. This same transducer was used to intermittently apply ultrasound with an MI that produced stable or inertial cavitation (IC) for 10 min through a tissue-mimicking phantom. A nitric oxide inhibitor, L-Nω-nitroarginine methyl ester (L-NAME), was pre-administered to six rats. Plateau microvascular contrast intensity quantified skeletal microvascular blood volume, and postmortem staining was used to detect perivascular hemorrhage. Intermittent IC impulses produced the greatest recovery of microvascular blood volume (p < 0.0001, analysis of variance). Nitric oxide inhibition did not affect the skeletal microvascular blood volume improvement, but did result in more perivascular hemorrhage. IC inducing pulses from a diagnostic transducer can reverse microvascular obstruction after acute arterial thromboembolism. Nitric oxide may prevent unwanted bio-effects of these IC pulses. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  15. Biomechanics of the lower thoracic spine after decompression and fusion: a cadaveric analysis.

    PubMed

    Lubelski, Daniel; Healy, Andrew T; Mageswaran, Prasath; Benzel, Edward C; Mroz, Thomas E

    2014-09-01

    Few studies have evaluated the extent of biomechanical destabilization of thoracic decompression on the upper and lower thoracic spine. The present study evaluates lower thoracic spinal stability after laminectomy, unilateral facetectomy, and unilateral costotransversectomy in thoracic spines with intact sternocostovertebral articulations. To assess the biomechanical impact of decompression and fixation procedures on lower thoracic spine stability. Biomechanical cadaveric study. Sequential surgical decompression (laminectomy, unilateral facetectomy, unilateral costotransversectomy) and dorsal fixation were performed on the lower thoracic spine (T8-T9) of human cadaveric spine specimens with intact rib cages (n=10). An industrial robot was used to apply pure moments to simulate flexion-extension (FE), lateral bending (LB), and axial rotation (AR) in the intact specimens and after decompression and fixation. Global range of motion (ROM) between T1-T12 and intrinsic ROM between T7-T11 were measured for each specimen. The decompression procedures caused no statistically significant change in either global or intrinsic ROM compared with the intact state. Instrumentation, however, reduced global motion for AR (45° vs. 30°, p=.0001), FE (24° vs. 19°, p=.02), and LB (47° vs. 36°, p=.0001) and for intrinsic motion for AR (17° vs. 4°, p=.0001), FE (8° vs. 1°, p=.0001), and LB (12° vs. 1°, p=.0001). No significant differences were identified between decompression of the upper versus lower thoracic spine, with trends toward significantly greater ROM for AR and lower ROM for LB in the lower thoracic spine. The lower thoracic spine was not destabilized by sequential unilateral decompression procedures. Addition of dorsal fixation increased segment rigidity at intrinsic levels and also reduced overall ROM of the lower thoracic spine to a greater extent than did fusing the upper thoracic spine (level of the true ribs). Despite the lack of true ribs, the lower thoracic

  16. Arginase Inhibition Improves Microvascular Endothelial Function in Patients With Type 2 Diabetes Mellitus.

    PubMed

    Kövamees, Oskar; Shemyakin, Alexey; Checa, Antonio; Wheelock, Craig E; Lundberg, Jon O; Östenson, Claes-Göran; Pernow, John

    2016-11-01

    The development of microvascular complications in diabetes is a complex process in which endothelial dysfunction is important. Emerging evidence suggests that arginase is a key mediator of endothelial dysfunction in type 2 diabetes mellitus by reciprocally regulating nitric oxide bioavailability. The aim of this prospective intervention study was to test the hypothesis that arginase activity is increased and that arginase inhibition improves microvascular endothelial function in patients with type 2 diabetes and microvascular dysfunction. Microvascular endothelium-dependent and -independent dilatation was determined in patients with type 2 diabetes (n = 12) and healthy age-matched control subjects (n = 12) with laser Doppler flowmetry during iontophoretic application of acetylcholine and sodium nitroprusside, respectively, before and after administration of the arginase inhibitor N ω -hydroxy-nor-L-arginine (120 min). Plasma ratios of amino acids involved in arginase and nitric oxide synthase activities were determined. The laser Doppler flowmetry data were the primary outcome variable. Microvascular endothelium-dependent dilatation was impaired in subjects with type 2 diabetes (P < .05). After administration of N ω -hydroxy-nor-L-arginine, microvascular endothelial function improved significantly in patients with type 2 diabetes to the level observed in healthy controls. Endothelium-independent vasodilatation did not change significantly. Subjects with type 2 diabetes had higher levels of ornithine and higher ratios of ornithine/citrulline and ornithine/arginine (P < .05), suggesting increased arginase activity. Arginase inhibition improves microvascular endothelial function in patients with type 2 diabetes and microvascular dysfunction. Arginase inhibition may represent a novel therapeutic strategy to improve microvascular endothelial function in patients with type 2 diabetes.

  17. Iso-risk air no decompression limits after scoring marginal decompression sickness cases as non-events.

    PubMed

    Murphy, F Gregory; Swingler, Ashleigh J; Gerth, Wayne A; Howle, Laurens E

    2018-01-01

    Decompression sickness (DCS) in humans is associated with reductions in ambient pressure that occur during diving, aviation, or certain manned spaceflight operations. Its signs and symptoms can include, but are not limited to, joint pain, radiating abdominal pain, paresthesia, dyspnea, general malaise, cognitive dysfunction, cardiopulmonary dysfunction, and death. Probabilistic models of DCS allow the probability of DCS incidence and time of occurrence during or after a given hyperbaric or hypobaric exposure to be predicted based on how the gas contents or gas bubble volumes vary in hypothetical tissue compartments during the exposure. These models are calibrated using data containing the pressure and respired gas histories of actual exposures, some of which resulted in DCS, some of which did not, and others in which the diagnosis of DCS was not clear. The latter are referred to as marginal DCS cases. In earlier works, a marginal DCS event was typically weighted as 0.1, with a full DCS event being weighted as 1.0, and a non-event being weighted as 0.0. Recent work has shown that marginal DCS events should be weighted as 0.0 when calibrating gas content models. We confirm this indication in the present work by showing that such models have improved performance when calibrated to data with marginal DCS events coded as non-events. Further, we investigate the ramifications of derating marginal events on model-prescribed air diving no-stop limits. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Vasoregression: A Shared Vascular Pathology Underlying Macrovascular And Microvascular Pathologies?

    PubMed Central

    Gupta, Akanksha

    2015-01-01

    Abstract Vasoregression is a common phenomenon underlying physiological vessel development as well as pathological microvascular diseases leading to peripheral neuropathy, nephropathy, and vascular oculopathies. In this review, we describe the hallmarks and pathways of vasoregression. We argue here that there is a parallel between characteristic features of vasoregression in the ocular microvessels and atherosclerosis in the larger vessels. Shared molecular pathways and molecular effectors in the two conditions are outlined, thus highlighting the possible systemic causes of local vascular diseases. Our review gives us a system-wide insight into factors leading to multiple synchronous vascular diseases. Because shared molecular pathways might usefully address the diagnostic and therapeutic needs of multiple common complex diseases, the literature analysis presented here is of broad interest to readership in integrative biology, rational drug development and systems medicine. PMID:26669709

  19. Oscillations and Multiple Equilibria in Microvascular Blood Flow.

    PubMed

    Karst, Nathaniel J; Storey, Brian D; Geddes, John B

    2015-07-01

    We investigate the existence of oscillatory dynamics and multiple steady-state flow rates in a network with a simple topology and in vivo microvascular blood flow constitutive laws. Unlike many previous analytic studies, we employ the most biologically relevant models of the physical properties of whole blood. Through a combination of analytic and numeric techniques, we predict in a series of two-parameter bifurcation diagrams a range of dynamical behaviors, including multiple equilibria flow configurations, simple oscillations in volumetric flow rate, and multiple coexistent limit cycles at physically realizable parameters. We show that complexity in network topology is not necessary for complex behaviors to arise and that nonlinear rheology, in particular the plasma skimming effect, is sufficient to support oscillatory dynamics similar to those observed in vivo.

  20. A comparative evaluation of two decompression procedures for technical diving using inflammatory responses: compartmental versus ratio deco.

    PubMed

    Spisni, Enzo; Marabotti, Claudio; De Fazio, Luigia; Valerii, Maria Chiara; Cavazza, Elena; Brambilla, Stefano; Hoxha, Klarida; L'Abbate, Antonio; Longobardi, Pasquale

    2017-03-01

    The aim of this study was to compare two decompression procedures commonly adopted by technical divers: the ZH-L16 algorithm modified by 30/85 gradient factors (compartmental decompression model, CDM) versus the 'ratio decompression strategy' (RDS). The comparison was based on an analysis of changes in diver circulating inflammatory profiles caused by decompression from a single dive. Fifty-one technical divers performed a single trimix dive to 50 metres' sea water (msw) for 25 minutes followed by enriched air (EAN50) and oxygen decompression. Twenty-three divers decompressed according to a CDM schedule and 28 divers decompressed according to a RDS schedule. Peripheral blood for detection of inflammatory markers was collected before and 90 min after diving. Venous gas emboli were measured 30 min after diving using 2D echocardiography. Matched groups of 23 recreational divers (dive to 30 msw; 25 min) and 25 swimmers were also enrolled as control groups to assess the effects of decompression from a standard air dive or of exercise alone on the inflammatory profile. Echocardiography at the single 30 min observation post dive showed no significant differences between the two decompression procedures. Divers adopting the RDS showed a worsening of post-dive inflammatory profile compared to the CDM group, with significant increases in circulating chemokines CCL2 (P = 0.001) and CCL5 (P = 0.006) levels. There was no increase in chemokines following the CDM decompression. The air scuba group also showed a statistically significant increase in CCL2 (P < 0.001) and CCL5 (P = 0.003) levels post dive. No cases of decompression sickness occurred. The ratio deco strategy did not confer any benefit in terms of bubbles but showed the disadvantage of increased decompression-associated secretion of inflammatory chemokines involved in the development of vascular damage.

  1. Decompression Device Using a Stainless Steel Tube and Wire for Treatment of Odontogenic Cystic Lesions: A Technical Report.

    PubMed

    Jung, Eun-Joo; Baek, Jin-A; Leem, Dae-Ho

    2014-11-01

    Decompression is considered an effective treatment for odontogenic cystic lesions in the jaw. A variety of decompression devices are successfully used for the treatment of keratocystic odontogenic tumors, radicular cysts, dentigerous cysts, and ameloblastoma. The purpose of these devices is to keep an opening between the cystic lesion and the oral environment during treatment. The aim of this report is to describe an effective decompression tube using a stainless steel tube and wire for treatment of jaw cystic lesions.

  2. Novel Genetic Loci Associated with Retinal Microvascular Diameter

    PubMed Central

    Jensen, Richard A.; Sim, Xueling; Smith, Albert Vernon; Li, Xiaohui; Jakobsdóttir, Jóhanna; Cheng, Ching-Yu; Brody, Jennifer A.; Cotch, Mary Frances; Mcknight, Barbara; Klein, Ronald; Wang, Jie Jin; Kifley, Annette; Harris, Tamara B.; Launer, Lenore J.; Taylor, Kent D.; Klein, Barbara E.K.; Raffel, Leslie J.; Li, Xiang; Ikram, M. Arfan; Klaver, Caroline C.; van der Lee, Sven J.; Mutlu, Unal; Hofman, Albert; Uitterlinden, Andre G.; Liu, Chunyu; Kraja, Aldi T.; Mitchell, Paul; Gudnason, Vilmundur; Rotter, Jerome I.; Boerwinkle, Eric; van Duijn, Cornelia M.; Psaty, Bruce M.; Wong, Tien Y.

    2015-01-01

    Background There is increasing evidence that retinal microvascular diameters are associated with cardio- and cerebrovascular conditions. The shared genetic effects of these associations are currently unknown. The aim of this study was to increase our understanding of the genetic factors that mediate retinal vessel size. Methods and Results This study extends previous genome-wide association study results using 24,000+ multi-ethnic participants from 7 discovery and 5,000+ subjects of European ancestry from 2 replication cohorts. Using the Illumina HumanExome BeadChip, we investigate the association of single nucleotide polymorphisms (SNPs) and variants collectively across genes with summary measures of retinal vessel diameters, referred to as the central retinal venule equivalent (CRVE) and the central retinal arteriole equivalent (CRAE). We report 4 new loci associated with CRVE, one of which is also associated with CRAE. The 4 SNPs are rs7926971 in TEAD1 (p=3.1×10−11, minor allele frequency (MAF)=0.43), rs201259422 in TSPAN10 (p=4.4×10−9, MAF=0.27), rs5442 in GNB3 (p=7.0×10−10, MAF=0.05) and rs1800407 in OCA2 (p=3.4×10−8, MAF=0.05). The latter SNP, rs1800407, was also associated with CRAE (p=6.5×10−12). Results from the gene-based burden tests were null. In phenotype look-ups, SNP rs201255422 was associated with both systolic (p=0.001) and diastolic blood pressure (p=8.3×10−04). Conclusions Our study expands the understanding of genetic factors influencing the size of the retinal microvasculature. These findings may also provide insight into the relationship between retinal and systemic microvascular disease. PMID:26567291

  3. Microvascular Responsiveness to Pulsatile and Nonpulsatile Flow During Cardiopulmonary Bypass.

    PubMed

    O'Neil, Michael P; Alie, Rene; Guo, Linrui Ray; Myers, Mary-Lee; Murkin, John M; Ellis, Christopher G

    2018-06-01

    Pulsatile perfusion may offer microcirculatory advantages over conventional nonpulsatile perfusion during cardiopulmonary bypass (CPB). Here, we present direct visual evidence of microvascular perfusion and vasoreactivity between perfusion modalities. A prospective, randomized cohort study of 20 high-risk cardiac surgical patients undergoing pulsatile (n = 10) or nonpulsatile (n = 10) flow during CPB was conducted. Changes in sublingual mucosal microcirculation were assessed with orthogonal polarization spectral imaging along with near-infrared spectroscopic indices of thenar muscle tissue oxygen saturation (StO 2 ) and its recovery during a vascular occlusion test at the following time points: baseline (T 0 ), 30 minutes on CPB (T 1 ), 90 minutes on CPB (T 2 ), 1 hour after CPB (T 3 ), and 24 hours after CPB (T 4 ). On the basis of our scoring scale, a shift in microcirculatory blood flow occurred over time. The pulsatile group maintained normal perfusion characteristics, whereas the nonpulsatile group exhibited deterioration in perfusion during CPB (T 2 : 74.0% ± 5.6% versus 57.6% ± 5.0%) and after CPB (T 3 : 76.2% ± 2.7% versus 58.9% ± 5.2%, T 4 : 85.7% ± 2.6% versus 69.8% ± 5.9%). Concurrently, no important differences were found between groups in baseline StO 2 and consumption slope at all time points. Reperfusion slope was substantially different between groups 24 hours after CPB (T 4 : 6.1% ± 0.6% versus 3.7% ± 0.5%), indicating improved microvascular responsiveness in the pulsatile group versus the nonpulsatile group. Pulsatility generated by the roller pump during CPB improves microcirculatory blood flow and tissue oxygen saturation compared with nonpulsatile flow in high-risk cardiac surgical patients, which may reflect attenuation of the systemic inflammatory response and ischemia-reperfusion injury. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  4. Nanoparticle inhalation augments particle-dependent systemic microvascular dysfunction

    PubMed Central

    Nurkiewicz, Timothy R; Porter, Dale W; Hubbs, Ann F; Cumpston, Jared L; Chen, Bean T; Frazer, David G; Castranova, Vincent

    2008-01-01

    Background We have shown that pulmonary exposure to fine particulate matter (PM) impairs endothelium dependent dilation in systemic arterioles. Ultrafine PM has been suggested to be inherently more toxic by virtue of its increased surface area. The purpose of this study was to determine if ultrafine PM (or nanoparticle) inhalation produces greater microvascular dysfunction than fine PM. Rats were exposed to fine or ultrafine TiO2 aerosols (primary particle diameters of ~1 μm and ~21 nm, respectively) at concentrations which do not alter bronchoalveolar lavage markers of pulmonary inflammation or lung damage. Results By histopathologic evaluation, no significant inflammatory changes were seen in the lung. However, particle-containing macrophages were frequently seen in intimate contact with the alveolar wall. The spinotrapezius muscle was prepared for in vivo microscopy 24 hours after inhalation exposures. Intraluminal infusion of the Ca2+ ionophore A23187 was used to evaluate endothelium-dependent arteriolar dilation. In control rats, A23187 infusion produced dose-dependent arteriolar dilations. In rats exposed to fine TiO2, A23187 infusion elicited vasodilations that were blunted in proportion to pulmonary particle deposition. In rats exposed to ultrafine TiO2, A23187 infusion produced arteriolar constrictions or significantly impaired vasodilator responses as compared to the responses observed in control rats or those exposed to a similar pulmonary load of fine particles. Conclusion These observations suggest that at equivalent pulmonary loads, as compared to fine TiO2, ultrafine TiO2 inhalation produces greater remote microvascular dysfunction. PMID:18269765

  5. Evaluation of Microvascular Perfusion and Resuscitation after Severe Injury.

    PubMed

    Lee, Yann-Leei L; Simmons, Jon D; Gillespie, Mark N; Alvarez, Diego F; Gonzalez, Richard P; Brevard, Sidney B; Frotan, Mohammad A; Schneider, Andrew M; Richards, William O

    2015-12-01

    Achieving adequate perfusion is a key goal of treatment in severe trauma; however, tissue perfusion has classically been measured by indirect means. Direct visualization of capillary flow has been applied in sepsis, but application of this technology to the trauma population has been limited. The purpose of this investigation was to compare the efficacy of standard indirect measures of perfusion to direct imaging of the sublingual microcirculatory flow during trauma resuscitation. Patients with injury severity scores >15 were serially examined using a handheld sidestream dark-field video microscope. In addition, measurements were also made from healthy volunteers. The De Backer score, a morphometric capillary density score, and total vessel density (TVD) as cumulative vessel area within the image, were calculated using Automated Vascular Analysis (AVA3.0) software. These indices were compared against clinical and laboratory parameters of organ function and systemic metabolic status as well as mortality. Twenty severely injured patients had lower TVD (X = 14.6 ± 0.22 vs 17.66 ± 0.51) and De Backer scores (X = 9.62 ± 0.16 vs 11.55 ± 0.37) compared with healthy controls. These scores best correlated with serum lactate (TVD R(2) = 0.525, De Backer R(2) = 0.576, P < 0.05). Mean arterial pressure, heart rate, oxygen saturation, pH, bicarbonate, base deficit, hematocrit, and coagulation parameters correlated poorly with both TVD and De Backer score. Direct measurement of sublingual microvascular perfusion is technically feasible in trauma patients, and seems to provide real-time assessment of microcirculatory perfusion. This study suggests that in severe trauma, many indirect measurements of perfusion do not correlate with microvascular perfusion. However, visualized perfusion deficiencies do reflect a shift toward anaerobic metabolism.

  6. Changes in retinal microvascular diameter in patients with diabetes

    PubMed Central

    da Silva, Andréa Vasconcellos Batista; Gouvea, Sonia Alves; da Silva, Aurélio Paulo Batista; Bortolon, Saulo; Rodrigues, Anabel Nunes; Abreu, Glaucia Rodrigues; Herkenhoff, Fernando Luiz

    2015-01-01

    Background and objectives Diabetic retinopathy is the main microvascular complication in diabetes mellitus and needs to be diagnosed early to prevent severe sight-threatening retinopathy. The purpose of this study was to quantify the retinal microvasculature pattern and analyze the influence of blood glucose level and the duration of diabetes mellitus on the retinal microvasculature. Methods Two groups were analyzed: patients with diabetes (N=26) and patients without diabetes, ie, controls (N=26). A quantitative semiautomated method analyzed retinal microvasculature. The diameters of arterioles and venules were measured. The total numbers of arterioles and venules were counted. The ratio of arteriole diameter to venule diameter was calculated. The retinal microvasculature pattern was related to clinical and biochemical parameters. Results Patients with diabetes exhibited larger venule diameters in the upper temporal quadrant of the retina compared to the lower temporal quadrant (124.85±38.03 µm vs 102.92±15.69 µm; P<0.01). Patients with diabetes for 5 or more years had larger venule diameters in the upper temporal quadrant than patients without diabetes (141.62±44.44 vs 112.58±32.11 µm; P<0.05). The degree of venodilation in the upper temporal quadrant was positively correlated with blood glucose level and the estimated duration of diabetes mellitus. Interpretation and conclusion The employed quantitative method demonstrated that patients with diabetes exhibited venule dilation in the upper temporal quadrant, and the duration of diabetes mellitus was positively correlated with blood glucose level. Therefore, the early assessment of retinal microvascular changes is possible prior to the onset of diabetic retinopathy. PMID:26345217

  7. Doxycycline Attenuates Lipopolysaccharide-Induced Microvascular Endothelial Cell Derangements.

    PubMed

    Wiggins-Dohlvik, Katie; Stagg, Hayden W; Han, Min Suk; Alluri, Himakarnika; Oakley, Ryan P; Anasooya Shaji, Chinchusha; Davis, Matthew L; Tharakan, Binu

    2016-06-01

    Lipopolysaccharide (LPS) is known to induce vascular derangements. The pathophysiology involved therein is unknown, but matrix metalloproteinases (MMPs) may be an important mediator. We hypothesized that in vitro LPS provokes vascular permeability, damages endothelial structural proteins, and increases MMP activity; that in vivo LPS increases permeability and fluid requirements; and that the MMP inhibitor doxycycline mitigates such changes. Rat lung microvascular endothelial cells were divided into four groups: control, LPS, LPS plus doxycycline, and doxycycline. Permeability, structural proteins β-catenin and Filamentous-actin, and MMP-9 activity were examined. Sprauge Dawley rats were divided into sham, IV LPS, and IV LPS plus IV doxycycline groups. Mesenteric postcapillary venules were observed. Blood pressure was measured as animals were resuscitated and fluid requirements were compared. Statistical analysis was conducted using Student's t-test and ANOVA. In vitro LPS increased permeability, damaged adherens junctions, induced actin stress fiber formation, and increased MMP-9 enzyme activity. In vivo, IV LPS administration induced vascular permeability. During resuscitation, significantly more fluid was necessary to maintain normotension in the IV LPS group. Doxycycline mitigated all derangements observed. We conclude that LPS increases permeability, damages structural proteins, and increases MMP-9 activity in endothelial cells. Additionally, endotoxemia induces hyperpermeability and increases the amount of IV fluid required to maintain normotension in vivo. Doxycycline mitigates such changes both in vitro and in vivo. Our findings illuminate the possible role of matrix metalloproteinases in the pathophysiology of lipopolysaccharide-induced microvascular hyperpermeability and pave the way for better understanding and treatment of this process.

  8. Peroxynitrite mediates testosterone-induced vasodilation of microvascular resistance vessels.

    PubMed

    Puttabyatappa, Yashoda; Stallone, John N; Ergul, Adviye; El-Remessy, Azza B; Kumar, Sanjiv; Black, Stephen; Johnson, Maribeth; Owen, Mary P; White, Richard E

    2013-04-01

    Our knowledge of how androgens influence the cardiovascular system is far from complete, and this lack of understanding is especially true of how androgens affect resistance vessels. Our aim was to identify the signaling mechanisms stimulated by testosterone (TES) in microvascular arteries and to understand how these mechanisms mediate TES-induced vasodilation. Mesenteric microvessels were isolated from male Sprague-Dawley rats. Tension studies demonstrated a rapid, concentration-dependent, vasodilatory response to TES that did not involve protein synthesis or aromatization to 17β-estradiol. Dichlorofluorescein fluorescence and nitrotyrosine immunoblot experiments indicated that TES stimulated peroxynitrite formation in microvessels, and functional studies demonstrated that TES-induced vasodilation was inhibited by scavenging peroxynitrite. As predicted, TES enhanced the production of both peroxynitrite precursors (i.e., superoxide and nitic oxide), and xanthine oxidase was identified as the likely source of TES-stimulated superoxide production. Functional and biochemical studies indicated that TES signaling involved activity of the phosphoinositide 3 (PI3) kinase-protein kinase B (Akt) cascade initiated by activation of the androgen receptor and culminated in enhanced production of cGMP and microvascular vasodilation. These findings, derived from a variety of analytical and functional approaches, provide evidence for a novel nongenomic signaling mechanism for androgen action in the microvasculature: TES-stimulated vasodilation mediated primarily by peroxynitrite formed from xanthine oxidase-generated superoxide and NO. This response was associated with activation of the PI3 kinase-Akt signaling cascade initiated by activation of the androgen receptor. We propose this mechanism could account for TES-stimulated cGMP production in microvessels and, ultimately, vasodilation.

  9. Peroxynitrite Mediates Testosterone-Induced Vasodilation of Microvascular Resistance Vessels

    PubMed Central

    Puttabyatappa, Yashoda; Stallone, John N.; Ergul, Adviye; El-Remessy, Azza B.; Kumar, Sanjiv; Black, Stephen; Johnson, Maribeth; Owen, Mary P.

    2013-01-01

    Our knowledge of how androgens influence the cardiovascular system is far from complete, and this lack of understanding is especially true of how androgens affect resistance vessels. Our aim was to identify the signaling mechanisms stimulated by testosterone (TES) in microvascular arteries and to understand how these mechanisms mediate TES-induced vasodilation. Mesenteric microvessels were isolated from male Sprague-Dawley rats. Tension studies demonstrated a rapid, concentration-dependent, vasodilatory response to TES that did not involve protein synthesis or aromatization to 17β-estradiol. Dichlorofluorescein fluorescence and nitrotyrosine immunoblot experiments indicated that TES stimulated peroxynitrite formation in microvessels, and functional studies demonstrated that TES-induced vasodilation was inhibited by scavenging peroxynitrite. As predicted, TES enhanced the production of both peroxynitrite precursors (i.e., superoxide and nitic oxide), and xanthine oxidase was identified as the likely source of TES-stimulated superoxide production. Functional and biochemical studies indicated that TES signaling involved activity of the phosphoinositide 3 (PI3) kinase-protein kinase B (Akt) cascade initiated by activation of the androgen receptor and culminated in enhanced production of cGMP and microvascular vasodilation. These findings, derived from a variety of analytical and functional approaches, provide evidence for a novel nongenomic signaling mechanism for androgen action in the microvasculature: TES-stimulated vasodilation mediated primarily by peroxynitrite formed from xanthine oxidase-generated superoxide and NO. This response was associated with activation of the PI3 kinase-Akt signaling cascade initiated by activation of the androgen receptor. We propose this mechanism could account for TES-stimulated cGMP production in microvessels and, ultimately, vasodilation. PMID:23318471

  10. Uterine microvascular sensitivity to nanomaterial inhalation: An in vivo assessment☆

    PubMed Central

    Stapleton, P.A.; McBride, C.R.; Yi, J.; Nurkiewicz, T.R.

    2015-01-01

    With the tremendous number and diverse applications of engineered nanomaterials incorporated in daily human activity, exposure can no longer be solely confined to occupational exposures of healthy male models. Cardiovascular and endothelial cell dysfunction have been established using in vitro and in situ preparations, but the translation to intact in vivo models is limited. Intravital microscopy has been used extensively to understand microvascular physiology while maintaining in vivo neurogenic, humoral, and myogenic control. However, a tissue specific model to assess the influences of nanomaterial exposure on female reproductive health has not been fully elucidated. Female Sprague Dawley (SD) rats were exposed to nano-TiO2 aerosols (171 ± 6 nm, 10.1 ± 0.39 mg/m3, 5 h) 24-hours prior to experimentation, leading to a calculated deposition of 42.0 ± 1.65 μg. After verifying estrus status, vital signs were monitored and the right horn of the uterus was exteriorized, gently secured over an optical pedestal, and enclosed in a warmed tissue bath using intravital microscopy techniques. After equilibration, significantly higher leukocyte-endothelium interactions were recorded in the exposed group. Arteriolar responsiveness was assessed using ionophoretically applied agents: muscarinic agonist acetylcholine (0.025 M; ACh; 20, 40, 100, and 200 nA), and nitric oxide donor sodium nitroprusside (0.05 M; SNP; 20, 40, and 100 nA), or adrenergic agonist phenylephrine (0.05 M; PE; 20, 40, and 100 nA) using glass micropipettes. Passive diameter was established by tissue superfusion with 10−4 M adenosine. Similar to male counterparts, female SD rats present systemic microvascular dysfunction; however the ramifications associated with female health and reproduction have yet to be elucidated. PMID:26375943

  11. The Role of Nitric Oxide during Sonoreperfusion of Microvascular Obstruction

    PubMed Central

    Yu, Francois T.H.; Chen, Xucai; Straub, Adam C.; Pacella, John J.

    2017-01-01

    Rationale: Microembolization during PCI for acute myocardial infarction can cause microvascular obstruction (MVO). MVO severely limits the success of reperfusion therapies, is associated with additional myonecrosis, and is linked to worse prognosis, including death. We have shown, both in in vitro and in vivo models, that ultrasound (US) and microbubble (MB) therapy (termed “sonoreperfusion” or “SRP”) is a theranostic approach that relieves MVO and restores perfusion, but the underlying mechanisms remain to be established. Objective: In this study, we investigated the role of nitric oxide (NO) during SRP. Methods and results: We first demonstrated in plated cells that US-stimulated MB oscillations induced a 6-fold increase in endothelial nitric oxide synthase (eNOS) phosphorylation in vitro. We then monitored the kinetics of intramuscular NO and perfusion flow rate responses following 2-min of SRP therapy in the rat hindlimb muscle, with and without blockade of eNOS with LNAME. Following SRP, we found that starting at 6 minutes, intramuscular NO increased significantly over 30 min and was higher than baseline after 13 min. Concomitant contrast enhanced burst reperfusion imaging confirmed that there was a marked increase in perfusion flow rate at 6 and 10 min post SRP compared to baseline (>2.5 fold). The increases in intramuscular NO and perfusion rate were blunted with LNAME. Finally, we tested the hypothesis that NO plays a role in SRP by assessing reperfusion efficacy in a previously described rat hindlimb model of MVO during blockade of eNOS. After US treatment 1, microvascular blood volume was restored to baseline in the MB+US group, but remained low in the LNAME group. Perfusion rates increased in the MB+US group after US treatment 2 but not in the MB+US+LNAME group. Conclusions: These data strongly support that MB oscillations can activate the eNOS pathway leading to increased blood perfusion and that NO plays a significant role in SRP efficacy. PMID

  12. Sagittal imbalance in patients with lumbar spinal stenosis and outcomes after simple decompression surgery.

    PubMed

    Shin, E Kyung; Kim, Chi Heon; Chung, Chun Kee; Choi, Yunhee; Yim, Dahae; Jung, Whei; Park, Sung Bae; Moon, Jung Hyeon; Heo, Won; Kim, Sung-Mi

    2017-02-01

    Lumbar spinal stenosis (LSS) is the most common lumbar degenerative disease, and sagittal imbalance is uncommon. Forward-bending posture, which is primarily caused by buckling of the ligamentum flavum, may be improved via simple decompression surgery. The objectives of this study were to identify the risk factors for sagittal imbalance and to describe the outcomes of simple decompression surgery. This is a retrospective nested case-control study PATIENT SAMPLE: This was a retrospective study that included 83 consecutive patients (M:F=46:37; mean age, 68.5±7.7 years) who underwent decompression surgery and a minimum of 12 months of follow-up. The primary end point was normalization of sagittal imbalance after decompression surgery. Sagittal imbalance was defined as a C7 sagittal vertical axis (SVA) ≥40 mm on a 36-inch-long lateral whole spine radiograph. Logistic regression analysis was used to identify the risk factors for sagittal imbalance. Bilateral decompression was performed via a unilateral approach with a tubular retractor. The SVA was measured on serial radiographs performed 1, 3, 6, and 12 months postoperatively. The prognostic factors for sagittal balance recovery were determined based on various clinical and radiological parameters. Sagittal imbalance was observed in 54% (45/83) of patients, and its risk factors were old age and a large mismatch between pelvic incidence and lumbar lordosis. The 1-year normalization rate was 73% after decompression surgery, and the median time to normalization was 1 to 3 months. Patients who did not experience SVA normalization exhibited low thoracic kyphosis (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.02-1.10) (p<.01) and spondylolisthesis (HR, 0.33; 95% CI, 0.17-0.61) before surgery. Sagittal imbalance was observed in more than 50% of LSS patients, but this imbalance was correctable via simple decompression surgery in 70% of patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. MRI Evaluation of Post Core Decompression Changes in Avascular Necrosis of Hip.

    PubMed

    Nori, Madhavi; Marupaka, Sravan Kumar; Alluri, Swathi; Md, Naseeruddin; Irfan, Kazi Amir; Jampala, Venkateshwarlu; Apsingi, Sunil; Eachempati, Krishna Kiran

    2015-12-01

    Avascular necrosis of hip typically presents in young patients. Core decompression in precollapse stage provides pain relief and preservation of femoral head. The results of core decompression vary considerably despite early diagnosis. The role of MRI in monitoring patients post surgically has not been clearly defined. To study pre and post core decompression MRI changes in avascular necrosis of hip. This is a contiguous observational cohort of 40 hips treated by core decompression for precollapse avascular necrosis of femoral head, who had a baseline MRI performed before surgery. Core decompression of the femoral head was performed within 4 weeks. Follow up radiograph and MRI scans were done at six months. Harris hip score preoperatively, 1 month and 6 months after the surgery was noted. Success in this study was defined as postoperative increase in Harris hip score (HHS) by 20 points and no additional femoral collapse. End point of clinical adverse outcome as defined by fall in Harris hip score was conversion or intention to convert to total hip replacement (THR). MRI parameters in the follow up scan were compared to the preoperative MRI. Effect of core decompression on bone marrow oedema and femoral head collapse was noted. Results were analysed using SPSS software version. Harris hip score improved from 57 to 80 in all patients initially. Six hips had a fall in Harris hip score to mean value of 34.1 during follow up (9 to 12 months) and underwent total hip replacement. MRI predictors of positive outcome are lesions with grade A extent, Grade A & B location. Bone marrow oedema with lesions less than 50% involvement, medial and central location. Careful selection of patients by MR criteria for core decompression provides satisfactory outcome in precollapse stage of avascular necrosis of hip.

  14. MRI Evaluation of Post Core Decompression Changes in Avascular Necrosis of Hip

    PubMed Central

    Marupaka, Sravan Kumar; Alluri, Swathi; MD, Naseeruddin; Irfan, Kazi Amir; Jampala, Venkateshwarlu; Apsingi, Sunil; Eachempati, Krishna Kiran

    2015-01-01

    Introduction Avascular necrosis of hip typically presents in young patients. Core decompression in precollapse stage provides pain relief and preservation of femoral head. The results of core decompression vary considerably despite early diagnosis. The role of MRI in monitoring patients post surgically has not been clearly defined. Aim To study pre and post core decompression MRI changes in avascular necrosis of hip. Materials and Methods This is a contiguous observational cohort of 40 hips treated by core decompression for precollapse avascular necrosis of femoral head, who had a baseline MRI performed before surgery. Core decompression of the femoral head was performed within 4 weeks. Follow up radiograph and MRI scans were done at six months. Harris hip score preoperatively, 1 month and 6 months after the surgery was noted. Success in this study was defined as postoperative increase in Harris hip score (HHS) by 20 points and no additional femoral collapse. End point of clinical adverse outcome as defined by fall in Harris hip score was conversion or intention to convert to total hip replacement (THR). MRI parameters in the follow up scan were compared to the preoperative MRI. Effect of core decompression on bone marrow oedema and femoral head collapse was noted. Results were analysed using SPSS software version. Results Harris hip score improved from 57 to 80 in all patients initially. Six hips had a fall in Harris hip score to mean value of 34.1 during follow up (9 to 12 months) and underwent total hip replacement. MRI predictors of positive outcome are lesions with grade A extent, Grade A & B location. Bone marrow oedema with lesions less than 50% involvement, medial and central location. Conclusion Careful selection of patients by MR criteria for core decompression provides satisfactory outcome in precollapse stage of avascular necrosis of hip. PMID:26816966

  15. Parameter estimation of the copernicus decompression model with venous gas emboli in human divers.

    PubMed

    Gutvik, Christian R; Dunford, Richard G; Dujic, Zeljko; Brubakk, Alf O

    2010-07-01

    Decompression Sickness (DCS) may occur when divers decompress from a hyperbaric environment. To prevent this, decompression procedures are used to get safely back to the surface. The models whose procedures are calculated from, are traditionally validated using clinical symptoms as an endpoint. However, DCS is an uncommon phenomenon and the wide variation in individual response to decompression stress is poorly understood. And generally, using clinical examination alone for validation is disadvantageous from a modeling perspective. Currently, the only objective and quantitative measure of decompression stress is Venous Gas Emboli (VGE), measured by either ultrasonic imaging or Doppler. VGE has been shown to be statistically correlated with DCS, and is now widely used in science to evaluate decompression stress from a dive. Until recently no mathematical model has existed to predict VGE from a dive, which motivated the development of the Copernicus model. The present article compiles a selection experimental dives and field data containing computer recorded depth profiles associated with ultrasound measurements of VGE. It describes a parameter estimation problem to fit the model with these data. A total of 185 square bounce dives from DCIEM, Canada, 188 recreational dives with a mix of single, repetitive and multi-day exposures from DAN USA and 84 experimentally designed decompression dives from Split Croatia were used, giving a total of 457 dives. Five selected parameters in the Copernicus bubble model were assigned for estimation and a non-linear optimization problem was formalized with a weighted least square cost function. A bias factor to the DCIEM chamber dives was also included. A Quasi-Newton algorithm (BFGS) from the TOMLAB numerical package solved the problem which was proved to be convex. With the parameter set presented in this article, Copernicus can be implemented in any programming language to estimate VGE from an air dive.

  16. Decompression management by 43 models of dive computer: single square-wave exposures to between 15 and 50 metres' depth.

    PubMed

    Sayer, Martin D J; Azzopardi, Elaine; Sieber, Arne

    2014-12-01

    Dive computers are used in some occupational diving sectors to manage decompression but there is little independent assessment of their performance. A significant proportion of occupational diving operations employ single square-wave pressure exposures in support of their work. Single examples of 43 models of dive computer were compressed to five simulated depths between 15 and 50 metres' sea water (msw) and maintained at those depths until they had registered over 30 minutes of decompression. At each depth, and for each model, downloaded data were used to collate the times at which the unit was still registering "no decompression" and the times at which various levels of decompression were indicated or exceeded. Each depth profile was replicated three times for most models. Decompression isopleths for no-stop dives indicated that computers tended to be more conservative than standard decompression tables at depths shallower than 30 msw but less conservative between 30-50 msw. For dives requiring decompression, computers were predominantly more conservative than tables across the whole depth range tested. There was considerable variation between models in the times permitted at all of the depth/decompression combinations. The present study would support the use of some dive computers for controlling single, square-wave diving by some occupational sectors. The choice of which makes and models to use would have to consider their specific dive management characteristics which may additionally be affected by the intended operational depth and whether staged decompression was permitted.

  17. Neurologic decompression sickness following cabin pressure fluctuations at high altitude.

    PubMed

    Auten, Jonathan D; Kuhne, Michael A; Walker, Harlan M; Porter, Henry O

    2010-04-01

    Decompression sickness (DCS) occurs in diving, altitude chamber exposures, and unpressurized or depressurized high-altitude flights. Because DCS takes many forms, in-flight cases may be misinterpreted as hypoxia, hyperventilation, or viral illness, with resulting failure to respond appropriately. In this case, a 28-yr-old male pilot of a single-seat, tactical aircraft experienced 12 rapid pressure fluctuations while flying at 43,000 ft above sea level. He had no symptoms and decided to complete the flight, which required an additional 2 h in the air. Approximately 1 h later he began to experience fatigue, lightheadedness, and confusion, which he interpreted as onset of a viral illness. However, symptoms progressed to visual, cognitive, motor, and sensory degradations and it was with some difficulty that he landed safely at his destination. Neurologic DCS was suspected on initial evaluation by flight line medical personnel because of the delayed onset and symptom progression. He was transferred to a local Emergency Department and noted to have altered mental status, asymmetric motor deficits, and non-dermatomal paresthesias of the upper and lower extremities. Approximately 3.5 h after the incident and 2.5 h after the onset of symptoms he began hyperbaric oxygen therapy. He received partial relief at 30 min of the Navy DiveTable 6 and full resolution at 90 min; there were no recurrent symptoms at a 1-yr follow-up. This case highlights the importance of early recognition of in-flight DCS symptoms and landing as soon as possible rather than as soon as practical in all likely scenarios.

  18. Cost-Effectiveness of Postoperative Ketamine in Chiari Decompression.

    PubMed

    McDowell, Michael M; Alhourani, Ahmad; Pearce-Smith, Beverly A; Mazurkiewicz, Anna; Friedlander, Robert M

    2018-02-01

    In Chiari I patients, postoperative pain and discomfort frequently slow the transition back to the home setting. We sought to determine the effect of standardized ketamine infusion protocols on hospital length of stay (LOS). This retrospective cohort study reviewed 100 consecutive adult patients undergoing Chiari I decompression. Fifty-nine patients were placed on a 2-3 mg/hr ketamine drip until postoperative day 1. This group was compared with a group who received 2-3 mg/hr of ketamine until postoperative day 2 (19 patients) and patients who did not receive ketamine at all (22 patients). Clinical characteristics, opioid use, LOS, and relative hospitalization costs were assessed. All narcotic amounts were converted into milligram equivalents of morphine. LOS of the short-ketamine group was 46.5 hours when compared with the long-ketamine group (66.8 hours) and no-ketamine group (56.9 hours). There was a statistically significant difference when comparing the short-ketamine group with the long-ketamine group and no-ketamine group together (P < 0.001), as well as when compared individually (P = 0.001 and 0.004). The mean cost of hospitalization was 20% less when a short-ketamine protocol was used (P < 0.001). Mean morphine milligram equivalents used postoperatively were 148 mg in the short-ketamine group, 196 mg in the long-ketamine group, and 187 mg in the no-ketamine group (P = 0.65). No adverse events from ketamine were noted. Ketamine at subanesthetic levels may be an effective tool to facilitate early return home postoperatively and may significantly reduce medical costs. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Pudendal nerve decompression in perineology : a case series

    PubMed Central

    Beco, Jacques; Climov, Daniela; Bex, Michèle

    2004-01-01

    Background Perineodynia (vulvodynia, perineal pain, proctalgia), anal and urinary incontinence are the main symptoms of the pudendal canal syndrome (PCS) or entrapment of the pudendal nerve. The first aim of this study was to evaluate the effect of bilateral pudendal nerve decompression (PND) on the symptoms of the PCS, on three clinical signs (abnormal sensibility, painful Alcock's canal, painful "skin rolling test") and on two neurophysiological tests: electromyography (EMG) and pudendal nerve terminal motor latencies (PNTML). The second aim was to study the clinical value of the aforementioned clinical signs in the diagnosis of PCS. Methods In this retrospective analysis, the studied sample comprised 74 female patients who underwent a bilateral PND between 1995 and 2002. To accomplish the first aim, the patients sample was compared before and at least one year after surgery by means of descriptive statistics and hypothesis testing. The second aim was achieved by means of a statistical comparison between the patient's group before the operation and a control group of 82 women without any of the following signs: prolapse, anal incontinence, perineodynia, dyschesia and history of pelvi-perineal surgery. Results When bilateral PND was the only procedure done to treat the symptoms, the cure rates of perineodynia, anal incontinence and urinary incontinence were 8/14, 4/5 and 3/5, respectively. The frequency of the three clinical signs was significantly reduced. There was a significant reduction of anal and perineal PNTML and a significant increase of anal richness on EMG. The Odd Ratio of the three clinical signs in the diagnosis of PCS was 16,97 (95% CI = 4,68 – 61,51). Conclusion This study suggests that bilateral PND can treat perineodynia, anal and urinary incontinence. The three clinical signs of PCS seem to be efficient to suspect this diagnosis. There is a need for further studies to confirm these preliminary results. PMID:15516268

  20. The effect of simulated weightlessness on hypobaric decompression sickness

    NASA Technical Reports Server (NTRS)

    Balldin, Ulf I.; Pilmanis, Andrew A.; Webb, James T.

    2002-01-01

    BACKGROUND: A discrepancy exists between the incidence of ground-based decompression sickness (DCS) during simulated extravehicular activity (EVA) at hypobaric space suit pressure (20-40%) and crewmember reports during actual EVA (zero reports). This could be due to the effect of gravity during ground-based DCS studies. HYPOTHESIS: At EVA suit pressures of 29.6 kPa (4.3 psia), there is no difference in the incidence of hypobaric DCS between a control group and group exposed to simulated weightlessness (supine body position). METHODS: Male subjects were exposed to a hypobaric pressure of 29.6 kPa (4.3 psi) for up to 4 h. The control group (n = 26) pre-oxygenated for 60 min (first 10 min exercising) before hypobaric exposure and walking around in the altitude chamber. The test group (n = 39) remained supine for a 3 h prior to and during the 60-min pre-oxygenation (also including exercise) and at hypobaric pressure. DCS symptoms and venous gas emboli (VGE) at hypobaric pressure were registered. RESULTS: DCS occurred in 42% in the control and in 44% in simulated weightlessness group (n.s.). The mean time for DCS to develop was 112 min (SD +/- 61) and 123 min (+/- 67), respectively. VGE occurred in 81% of the control group subjects and in 51% of the simulated weightlessness subjects (p = 0.02), while severe VGE occurred in 58% and 33%, respectively (p = 0.08). VGE started after 113 min (+/- 43) in the control and after 76 min (+/- 64) in the simulated weightlessness group. CONCLUSIONS: No difference in incidence of DCS was shown between control and simulated weightlessness conditions. VGE occurred more frequently during the control condition with bubble-releasing arm and leg movements.

  1. Association of microparticles and neutrophil activation with decompression sickness.

    PubMed

    Thom, Stephen R; Bennett, Michael; Banham, Neil D; Chin, Walter; Blake, Denise F; Rosen, Anders; Pollock, Neal W; Madden, Dennis; Barak, Otto; Marroni, Alessandro; Balestra, Costantino; Germonpre, Peter; Pieri, Massimo; Cialoni, Danilo; Le, Phi-Nga Jeannie; Logue, Christopher; Lambert, David; Hardy, Kevin R; Sward, Douglas; Yang, Ming; Bhopale, Veena B; Dujic, Zeljko

    2015-09-01

    Decompression sickness (DCS) is a systemic disorder, assumed due to gas bubbles, but additional factors are likely to play a role. Circulating microparticles (MPs)--vesicular structures with diameters of 0.1-1.0 μm--have been implicated, but data in human divers have been lacking. We hypothesized that the number of blood-borne, Annexin V-positive MPs and neutrophil activation, assessed as surface MPO staining, would differ between self-contained underwater breathing-apparatus divers suffering from DCS vs. asymptomatic divers. Blood was analyzed from 280 divers who had been exposed to maximum depths from 7 to 105 meters; 185 were control/asymptomatic divers, and 90 were diagnosed with DCS. Elevations of MPs and neutrophil activation occurred in all divers but normalized within 24 h in those who were asymptomatic. MPs, bearing the following proteins: CD66b, CD41, CD31, CD142, CD235, and von Willebrand factor, were between 2.4- and 11.7-fold higher in blood from divers with DCS vs. asymptomatic divers, matched for time of sample acquisition, maximum diving depth, and breathing gas. Multiple logistic regression analysis documented significant associations (P < 0.001) between DCS and MPs and for neutrophil MPO staining. Effect estimates were not altered by gender, body mass index, use of nonsteroidal anti-inflammatory agents, or emergency oxygen treatment and were modestly influenced by divers' age, choice of breathing gas during diving, maximum diving depth, and whether repetitive diving had been performed. There were no significant associations between DCS and number of MPs without surface proteins listed above. We conclude that MP production and neutrophil activation exhibit strong associations with DCS. Copyright © 2015 the American Physiological Society.

  2. Gut fermentation seems to promote decompression sickness in humans.

    PubMed

    de Maistre, Sébastien; Vallee, Nicolas; Gempp, Emmanuel; Louge, Pierre; Duchamp, Claude; Blatteau, Jean-Eric

    2016-10-01

    Massive bubble formation after diving can lead to decompression sickness (DCS) that can result in neurological disorders. In experimental dives using hydrogen as the diluent gas, decreasing the body's H 2 burden by inoculating hydrogen-metabolizing microbes into the gut reduces the risk of DCS. In contrast, we have shown that gut bacterial fermentation in rats on a standard diet promotes DCS through endogenous hydrogen production. Therefore, we set out to test these experimental results in humans. Thirty-nine divers admitted into our hyperbaric center with neurological DCS (Affected Divers) were compared with 39 healthy divers (Unaffected Divers). Their last meal time and composition were recorded. Gut fermentation rate was estimated by measuring breath hydrogen 1-4 h after the dive. Breath hydrogen concentrations were significantly higher in Affected Divers (15 ppm [6-23] vs. 7 ppm [3-12]; P = 0.0078). With the use of a threshold value of 16.5 ppm, specificity was 87% [95% confidence interval (CI) 73-95] for association with neurological DCS onset. We observed a strong association between hydrogen values above this threshold and an accident occurrence (odds ratio = 5.3, 95% CI 1.8-15.7, P = 0.0025). However, high fermentation potential foodstuffs consumption was not different between Affected and Unaffected Divers. Gut fermentation rate at dive time seemed to be higher in Affected Divers. Hydrogen generated by fermentation diffuses throughout the body and could increase DCS risk. Prevention could be helped by excluding divers who are showing a high fermentation rate, by eliminating gas produced in gut, or even by modifying intestinal microbiota to reduce fermentation rate during a dive. Copyright © 2016 the American Physiological Society.

  3. Supraorbital keyhole surgery for optic nerve decompression and dura repair.

    PubMed

    Chen, Yuan-Hao; Lin, Shinn-Zong; Chiang, Yung-Hsiao; Ju, Da-Tong; Liu, Ming-Ying; Chen, Guann-Juh

    2004-07-01

    Supraorbital keyhole surgery is a limited surgical procedure with reduced traumatic manipulation of tissue and entailing little time in the opening and closing of wounds. We utilized the approach to treat head injury patients complicated with optic nerve compression and cerebrospinal fluid leakage (CSF). Eleven cases of basal skull fracture complicated with either optic nerve compression and/or CSF leakage were surgically treated at our department from February 1995 to June 1999. Six cases had primary optic nerve compression, four had CSF leakage and one case involved both injuries. Supraorbital craniotomy was carried out using a keyhole-sized burr hole plus a small craniotomy. The size of craniotomy approximated 2 x 3 cm2. The optic nerve was decompressed via removal of the optic canal roof and anterior clinoid process with high-speed drills. The defect of dura was repaired with two pieces of tensa fascia lata that were attached on both sides of the torn dural defect with tissue glue. Seven cases with optic nerve injury included five cases of total blindness and two cases of light perception before operation. Vision improved in four cases. The CSF leakage was stopped successfully in all four cases without complication. As optic nerve compression and CSF leakage are skull base lesions, the supraorbital keyhole surgery constitutes a suitable approach. The supraorbital keyhole surgery allows for an anterior approach to the skull base. This approach also allows the treatment of both CSF leakage and optic nerve compression. Our results indicate that supraorbital keyhole operation is a safe and effective method for preserving or improving vision and attenuating CSF leakage following injury.

  4. Outcome after decompressive craniectomy for the treatment of severe traumatic brain injury.

    PubMed

    Howard, Jerry Lee; Cipolle, Mark D; Anderson, Meredith; Sabella, Victoria; Shollenberger, Daniele; Li, P Mark; Pasquale, Michael D

    2008-08-01

    Using decompressive craniectomy as part of the treatment regimen for severe traumatic brain injury (STBI) has become more common at our Level I trauma center. This study was designed to examine this practice with particular attention to long-term functional outcome. A retrospective review of prospectively collected data was performed for patients with STBI admitted from January 1, 2003 to December 31, 2005. Our institution manages patients using the Brain Trauma Foundation Guidelines. Data collected from patients undergoing decompressive craniectomy included: age, Injury Severity Score, admission and follow-up Glasgow Coma Score, timing of, and indication for decompressive craniectomy, and procedure-related complications. The Extended Glasgow Outcome Scale (GOSE) was performed by a experienced trauma clinical research coordinator using a structured phone interview to assess long-term outcome in the survivors. Student's t test and chi2 were used to examine differences between groups. Forty STBI patients were treated with decompressive craniectomy; 24 were performed primarily in conjunction with urgent evacuation of extra-axial hemorrhage and 16 were performed primarily in response to increased intracranial pressure with 4 of these after an initial craniotomy. Decompressive craniectomy was very effective at lowering intracranial pressure in these 16 patients (35.0 mm Hg +/- 13.5 mm Hg to 14.6 mm Hg +/- 8.7 mm Hg, p = 0.005). Twenty-two decompressive craniectomy patients did not survive to hospital discharge, whereas admission Glasgow Coma Score and admission pupil size and reactivity correlated with outcome, age, and Injury Severity Score did not. At a mean of 11 months (range, 3-26 months) after decompressive craniectomy, 6 survivors had a poor functional outcome (GOSE 1-4), whereas 12 survivors had a good outcome (GOSE 5-8). Therefore, 70% of these patients had an unfavorable outcome (death or severe disability), and 30% had a favorable long-term functional outcome

  5. Physiological consequences of rapid or prolonged aircraft decompression: evaluation using a human respiratory model.

    PubMed

    Wolf, Matthew

    2014-04-01

    Aircraft passengers and crew may be subjected to rapid or prolonged decompression to high cabin altitude when an aircraft develops a hole in the fuselage. The accepted measure of neurological damage due to the hypobaric hypoxia produced is the subjective 'time of useful consciousness' (TUC) measure, which is appropriate for pilots and crew who perform their given tasks, however, TUC is measured under conditions different than the decompression scenarios that passengers undergo in today's aircraft. Ernsting proposed that prolonged exposure to alveolar O2 pressures less than 30 mmHg (P30) causes neurological damage. The current study proposes that a critical value of arterial O2 saturation of 70% (S70) can be used in place of P30 and that this physiological measure is more suited for determination of hypobaric hypoxia in passengers. The study shows the equivalence of model-predicted P30 and S70 values in the Ernsting-decompression scenarios. The model is also used to predict values of these physiological measures in actual aircraft-decompression scenarios. The model can be used by others to quantitatively predict the degree of hypobaric hypoxia for virtually any kind of decompression scenario, including those where supplemental O2 is used. Use of this tool avoids the prohibitive costs of human-subject testing for new aircraft and the potential danger inherent in such tests.

  6. Optic neuropathy in thyroid eye disease: results of the balanced decompression technique.

    PubMed

    Baril, Catherine; Pouliot, Denis; Molgat, Yvonne

    2014-04-01

    To determine the efficacy of combined endoscopic medial and external lateral orbital decompression for the treatment of compressive optic neuropathy (CON) in thyroid eye disease (TED). A retrospective review of all patients undergoing combined surgical orbital decompression for CON between 2000 and 2010 was conducted. Fifty-nine eyes of 34 patients undergoing combined surgical orbital decompression for CON. Clinical outcome measures included visual acuity, Hardy-Rand-Rittler (HRR) colour plate testing, relative afferent pupillary defect, intraocular pressure measurement, and Hertel exophthalmometry. A CON score was calculated preoperatively and postoperatively based on the visual acuity and the missed HRR plates. A higher CON score correlates with more severe visual dysfunction. All patients had improvement of their optic neuropathy after surgical decompression. CON score was calculated for 54 eyes and decreased significantly from a mean of 13.2 ± 10.35 preoperatively to a mean of 8.51 ± 10.24 postoperatively (p < 0.0001). Optic neuropathy was completely resolved in 93.22% (55/59 eyes). Eighteen of 34 patients (52.94%) experienced development of new-onset postoperative strabismus that required subsequent surgical intervention. Endoscopic medial combined with external lateral orbital decompression is an effective technique for the treatment of TED-associated CON. © 2013 Canadian Ophthalmological Society Published by Canadian Ophthalmological Society All rights reserved.

  7. Electromagnetic image-guided orbital decompression: technique, principles, and preliminary experience with 6 consecutive cases.

    PubMed

    Servat, Juan J; Elia, Maxwell Dominic; Gong, Dan; Manes, R Peter; Black, Evan H; Levin, Flora

    2014-12-01

    To assess the feasibility of routine use of electromagnetic image guidance systems in orbital decompression. Six consecutive patients underwent stereotactic-guided three wall orbital decompression using the novel Fusion ENT Navigation System (Medtronic), a portable and expandable electromagnetic guidance system with multi-instrument tracking capabilities. The system consists of the Medtronic LandmarX System software-enabled computer station, signal generator, field-generating magnet, head-mounted marker coil, and surgical tracking instruments. In preparation for use of the LandmarX/Fusion protocol, all patients underwent preoperative non-contrast CT scan from the superior aspect of the frontal sinuses to the inferior aspect of the maxillary sinuses that includes the nasal tip. The Fusion ENT Navigation System (Medtronic™) was used in 6 patients undergoing maximal 3-wall orbital decompression for Graves' orbitopthy after a minimum of six months of disease inactivity. Preoperative Hertel exophthalmometry measured more than 27 mm in all patients. The navigation system proved to be no more difficult technically than the traditional orbital decompression approach. Electromagnetic image guidance is a stereotactic surgical navigation system that provides additional intraoperative flexibility in orbital surgery. Electromagnetic image-guidance offers the ability to perform more aggressive orbital decompressions with reduced risk.

  8. Exercise with prebreathe appears to increase protection from decompression sickness: Preliminary findings

    NASA Technical Reports Server (NTRS)

    Webb, James T.; Fischer, Michele D.; Heaps, Cristine L.; Pilmanis, Andrew A.

    1994-01-01

    Extravehicular activity (EVA) from the Space Shuttle involves one hour of prebreath with 100% oxygen, decompression of the entire Shuttle to 10.2 psia for at least 12 hours, and another prebreath for 40 minutes before decompression to the 4.3 psia suit pressure. We are investigating the use of a one-hour prebreathe with 100% oxygen beginning with a ten-minute strenuous exercise period as an alternative for the staged decompression schedule described above. The 10-minute exercise consists of dual-cycle ergometry performed at 75% of the subject's peak oxygen uptake to increase denitrogenation efficiency by increasing ventilation and perfusion. The control exposures were preceded by a one-hour prebreathe with 100% oxygen while resting in a supine position. The twenty-two male subjects were exposed to 4.3 psia for 4 hours while performing light to moderate exercise. Preliminary results from 22 of the planned 26 subjects indicate 76% DCS following supine, resting prebreathe and 38% following prebreathe with exercise. The staged decompression schedule has been shown to result in 23% DCS which is not significantly different from the exercise-enhanced prebreathe results. Prebreathe including exercise appears to be comparable to the protection afforded by the more lengthy staged decompression schedule. Completion of the study later this year will enable planned statistical analysis of the results.

  9. Systematic review of intraoperative colonic irrigation vs. manual decompression in obstructed left-sided colorectal emergencies.

    PubMed

    Kam, M H; Tang, C L; Chan, E; Lim, J F; Eu, K W

    2009-09-01

    A systematic review was conducted to determine if manual decompression is a safe alternative to intraoperative colonic irrigation prior to primary anastomosis in obstructed left-sided colorectal emergencies. Search for relevant articles from 1980 to 2007 was conducted on Medline, Embase and the Cochrane Controlled Trials Register using the keywords "colonic lavage, irrigation, decompression, washout, obstructed and bowel preparation", either singularly or in combination. Trials in English publications with similar patient characteristics, inclusion criteria and outcome measures were selected for analysis. Thirty-day mortality, anastomotic leak rates and post-operative wound infection were studied as outcome variables. Analysis was performed with RevMan 4.2 software. Seven trials were identified for systematic review, with a total of 449 patients. Data from the single randomised controlled trial and one prospective comparative trial were analysed separately. Results from the remaining five studies were pooled into two arms of a composite series, one with colonic irrigation and one without. Results showed no significant difference in the anastomotic leak rates and mortality rates between the colonic irrigation and manual decompression arms in the randomised and comparative trials. The composite series, however, showed significantly better results with manual decompression (RR 6.18, 95% CI 1.67-22.86). The post-operative infection rate was similar in both groups. Manual decompression was comparable to colonic irrigation for primary anastomosis in obstructed left-sided colorectal emergencies, with no significant increase in mortality, leak or infection rates.

  10. Experimental and computational studies on the femoral fracture risk for advanced core decompression.

    PubMed

    Tran, T N; Warwas, S; Haversath, M; Classen, T; Hohn, H P; Jäger, M; Kowalczyk, W; Landgraeber, S

    2014-04-01

    Two questions are often addressed by orthopedists relating to core decompression procedure: 1) Is the core decompression procedure associated with a considerable lack of structural support of the bone? and 2) Is there an optimal region for the surgical entrance point for which the fracture risk would be lowest? As bioresorbable bone substitutes become more and more common and core decompression has been described in combination with them, the current study takes this into account. Finite element model of a femur treated by core decompression with bone substitute was simulated and analyzed. In-vitro compression testing of femora was used to confirm finite element results. The results showed that for core decompression with standard drilling in combination with artificial bone substitute refilling, daily activities (normal walking and walking downstairs) are not risky for femoral fracture. The femoral fracture risk increased successively when the entrance point is located further distal. The critical value of the deviation of the entrance point to a more distal part is about 20mm. The study findings demonstrate that optimal entrance point should locate on the proximal subtrochanteric region in order to reduce the subtrochanteric fracture risk. Furthermore the consistent results of finite element and in-vitro testing imply that the simulations are sufficient. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Resolution of Tachyarrhythmia Following Posterior Fossa Decompression Surgery for Chiari Malformation Type I.

    PubMed

    Elia, Christopher; Brazdzionis, James; Tashjian, Vartan

    2018-03-01

    Chiari malformation (CM) type I commonly presents with symptoms such as tussive headaches, paresthesias, and, in severe cases, corticobulbar dysfunction. However, patients may present with atypical symptoms lending to the complexity in this patient population. We present a case of a CM patient presenting with atypical cardiac symptoms and arrhythmias, all of which resolved after surgical decompression. A 31-year-old female presented with atypical chest pain, palpitations, tachycardia, headaches, and dizziness for 2 years. Multiple antiarrhythmics and ultimately cardiac ablation procedure proved to be ineffective. Magnetic resonance imaging revealed CM, and the patient ultimately underwent surgical decompression with subsequent resolution of her symptoms. The surgical management of CM patients presenting with atypical symptoms can be challenging and often lead to delays in intervention. To our knowledge this is the only reported case of a patient presenting with tachyarrhythmia and atypical chest pain with resolution after Chiari decompression. We believe the dramatic improvement documented in the present case should serve to advance Chiari decompression in CM patients presenting with refractory tachyarrhythmia in whom no other discernable cause has been elucidated. Further studies are needed to better correlate the findings and to hopefully establish a criteria for patients that will likely benefit from surgical decompression. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. "White Cord Syndrome" of Acute Hemiparesis After Posterior Cervical Decompression and Fusion for Chronic Cervical Stenosis.

    PubMed

    Antwi, Prince; Grant, Ryan; Kuzmik, Gregory; Abbed, Khalid

    2018-05-01

    "White cord syndrome" is a very rare condition thought to be due to acute reperfusion of chronically ischemic areas of the spinal cord. Its hallmark is the presence of intramedullary hyperintense signal on T2-weighted magnetic resonance imaging sequences in a patient with unexplained neurologic deficits following spinal cord decompression surgery. The syndrome is rare and has been reported previously in 2 patients following anterior cervical decompression and fusion. We report an additional case of this complication. A 68-year-old man developed acute left-sided hemiparesis after posterior cervical decompression and fusion for cervical spondylotic myelopathy. The patient improved with high-dose steroid therapy. The rare white cord syndrome following either anterior cervical decompression and fusion or posterior cervical decompression and fusion may be due to ischemic-reperfusion injury sustained by chronically compressed parts of the spinal cord. In previous reports, patients have improved following steroid therapy and acute rehabilitation. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. [Analysis of decompression safety during extravehicular activity of astronauts in the light of probability theory].

    PubMed

    Nikolaev, V P; Katuntsev, V P

    1998-01-01

    Objectives of the study were comparative assessment of the risk of decompression sickness (DCS) in human subjects during shirt-sleeve simulation of extravehicular activity (EVA) following Russian and U.S. protocols, and analysis of causes of the difference between real and simulated EVA decompression safety. To this end, DCS risk during exposure to a sing-step decompression was estimated with an original method. According to the method, DCS incidence is determined by distribution of nucleation efficacy index (z) in the worst body tissues and its critical values (zm) as a function of initial nitrogen tension in these tissues and final ambient pressure post decompression. Gaussian distribution of z values was calculated basing on results of the DCS risk evaluation on the U.S. EVA protocol in an unsuited chamber test with various pre-breath procedures (Conkin et al., 1987). Half-time of nitrogen washout from the worst tissues was presumed to be 480 min. Calculated DCS risk during short-sleeve EVA simulation by the Russian and U.S. protocols with identical physical loading made up 19.2% and 23.4%, respectively. Effects of the working spacesuit pressure, spacesuit rigidity, metabolic rates during operations in EVA space suit, transcutaneous nitrogen exchange in the oxygen atmosphere of space suit, microgravity, analgesics, short compression due to spacesuit leak tests on the eye of EVA are discussed. Data of the study illustrate and advocate for high decompression safety of current Russian and U.S. EVA protocols.

  14. [Construction of 2-dimensional tumor microvascular architecture phenotype in non-small cell lung cancer].

    PubMed

    Liu, Jin-kang; Wang, Xiao-yi; Xiong, Zeng; Zhou, Hui; Zhou, Jian-hua; Fu, Chun-yan; Li, Bo

    2008-08-01

    To construct a technological platform of 2-dimensional tumor microvascular architecture phenotype (2D-TAMP) expression. Thirty samples of non-small cell lung cancer (NSCLC) were collected after surgery. The corresponding sections of tumor tissue specimens to the slice of CT perfusion imaging were selected. Immunohistochemical staining,Gomori methenamine silver stain, and electron microscope observation were performed to build a technological platform of 2D-TMAP expression by detecting the morphology and the integrity of basement membrane of microvasculature, microvascular density, various microvascular subtype, the degree of the maturity and lumenization of microvasculature, and the characteristics of immunogenetics of microvasculature. The technological platform of 2D-TMAP expression was constructed successfully. There was heterogeneity in 2D-TMAP expression of non-small cell lung cancer. The microvascular of NSCLC had certain characteristics. 2D-TMAP is a key technology that can be used to observe the overall state of micro-environment in tumor growth.

  15. SPONTANEOUSLY HYPERTENSIVE RATS ARE SUSCEPTIBLE TO MICROVASCULAR THROMBOSIS IN RESPONSE TO PARTICULATE MATTER EXPOSURE

    EPA Science Inventory

    SPONTANEOUSLY HYPERTENSIVE RATS ARE SUSCEPTIBLE TO MICROVASCULAR THROMBOSIS IN RESPONSE TO PARTICULATE MATTER EXPOSURE.
    PS Gilmour, MC Schladweiler, AD Ledbetter, and UP Kodavanti. US EPA, ORD, NHEERL, ETD, PTB, Research Triangle Park, NC USA.
    Environmental particles (PM...

  16. Monitoring skin microvascular dysfunction of type 1 diabetic mice using in vivo skin optical clearing

    NASA Astrophysics Data System (ADS)

    Feng, Wei; Shi, Rui; Zhu, Dan

    2018-02-01

    To monitor skin microvascular dysfunction of alloxan-induced type 1 diabetic mice model. In this work, we used laser speckle contrast imaging and hyperspectral imaging through in vivo skin optical clearing method to simultaneously monitor the noradrenaline-induced response of microvascular blood flow and blood oxygen with the development of diabetes. The main results showed that venous and arterious blood flow steadily decreased without recovery after injecting noradrenaline (NE), furthermore the influence of NE-induced arterious blood oxygen response greatly decreased, especially for 2-weeks and 4-weeks diabetic mice. This study demonstrated that skin microvascular function was a potential research biomarker for early warning in the occurrence and development of diabetes. And it provides a feasible solution to realize visualization of cutaneous microvessels for monitoring microvascular reactivity.

  17. Microvascular dysfunction in the immediate aftermath of chronic total coronary occlusion recanalization.

    PubMed

    Ladwiniec, Andrew; Cunnington, Michael S; Rossington, Jennifer; Thackray, Simon; Alamgir, Farquad; Hoye, Angela

    2016-05-01

    The aim of this study was to compare microvascular resistance under both baseline and hyperemic conditions immediately after percutaneous coronary intervention (PCI) of a chronic total occlusion (CTO) with an unobstructed reference vessel in the same patient Microvascular dysfunction has been reported to be prevalent immediately after CTO PCI. However, previous studies have not made comparison with a reference vessel. Patients with a CTO may have global microvascular and/or endothelial dysfunction, making comparison with established normal values misleading. After successful CTO PCI in 21 consecutive patients, coronary pressure and flow velocity were measured at baseline and hyperemia in distal segments of the CTO/target vessel and an unobstructed reference vessel. Hemodynamics including hyperemic microvascular resistance (HMR), basal microvascular resistance (BMR), and instantaneous minimal microvascular resistance at baseline and hyperemia were calculated and compared between reference and target/CTO vessels. After CTO PCI, BMR was reduced in the target/CTO vessel compared with the reference vessel: 3.58 mm Hg/cm/s vs 4.94 mm Hg/cm/s, difference -1.36 mm Hg/cm/s (-2.33 to -0.39, p = 0.008). We did not detect a difference in HMR: 1.82 mm Hg/cm/s vs 2.01 mm Hg/cm/s, difference -0.20 (-0.78 to 0.39, p = 0.49). Instantaneous minimal microvascular resistance correlated strongly with the length of stented segment at baseline (r = 0.63, p = 0.005) and hyperemia (r = 0.68, p = 0.002). BMR is reduced in a recanalized CTO in the immediate aftermath of PCI compared to an unobstructed reference vessel; however, HMR appears to be preserved. A longer stented segment is associated with increased microvascular resistance. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. GM-CSF ameliorates microvascular barrier integrity via pericyte-derived Ang-1 in wound healing.

    PubMed

    Yan, Min; Hu, Yange; Yao, Min; Bao, Shisan; Fang, Yong

    2017-11-01

    Skin wound healing involves complex coordinated interactions of cells, tissues, and mediators. Maintaining microvascular barrier integrity is one of the key events for endothelial homeostasis during wound healing. Vasodilation is observed after vasoconstriction, which causes blood vessels to become porous, facilitates leukocyte infiltration and aids angiogenesis at the wound-area, postinjury. Eventually, vessel integrity has to be reestablished for vascular maturation. Numerous studies have found that granulocyte macrophage colony-stimulating factor (GM-CSF) accelerates wound healing by inducing recruitment of repair cells into the injury area and releases of cytokines. However, whether GM-CSF is involving in the maintaining of microvascular barrier integrity and the underlying mechanism remain still unclear. Aim of this study was to investigate the effects of GM-CSF on modulation of microvascular permeability in wound healing and underlying mechanisms. Wound closure and microvascular leakage was investigated using a full-thickness skin wound mouse model after GM-CSF intervention. The endothelial permeability was measured by Evans blue assay in vivo and in vitro endothelium/pericyte co-culture system using a FITC-Dextran permeability assay. To identify the source of angiopoietin-1 (Ang-1), double staining is used in vivo and ELISA and qPCR are used in vitro. To determine the specific effect of Ang-1 on GM-CSF maintaining microvascular stabilization, Ang-1 siRNA was applied to inhibit Ang-1 production in vivo and in vitro. Wound closure was significantly accelerated and microvascular leakage was ameliorated after GM-CSF treatment in mouse wound sites. GM-CSF decreased endothelial permeability through tightening endothelial junctions and increased Ang-1 protein level that was derived by perictye. Furthermore, applications of siRNAAng-1 inhibited GM-CSF mediated protection of microvascular barrier integrity both in vivo and in vitro. Our data indicate that GM

  19. Is endothelial microvascular function equally impaired among patients with chronic Chagas and ischemic cardiomyopathy?

    PubMed

    Borges, Juliana Pereira; Mendes, Fernanda de Souza Nogueira Sardinha; Lopes, Gabriella de Oliveira; Sousa, Andréa Silvestre de; Mediano, Mauro Felippe Felix; Tibiriçá, Eduardo

    2018-08-15

    Chronic Chagas cardiomyopathy (CCC) and cardiomyopathies due to other etiologies involve differences in pathophysiological pathways that are still unclear. Systemic microvascular abnormalities are associated with the pathogenesis of ischemic heart disease. However, systemic microvascular endothelial function in CCC remains to be elucidated. Thus, we compared the microvascular endothelial function of patients presenting with CCC to those with ischemic cardiomyopathy disease. Microvascular reactivity was assessed in 21 patients with cardiomyopathy secondary to Chagas disease, 21 patients with cardiomyopathy secondary to ischemic disease and 21 healthy controls. Microvascular blood flow was assessed in the skin of the forearm using laser speckle contrast imaging coupled with iontophoresis of acetylcholine (ACh). Peak increase in forearm blood flow with ACh iontophoresis in relation to baseline was greater in healthy controls than in patients with heart disease (controls: 162.7 ± 58.4% vs. ischemic heart disease: 74.1 ± 48.3% and Chagas: 85.1 ± 68.1%; p < 0.0001). Patients with Chagas and ischemic cardiomyopathy presented similar ACh-induced changes from baseline in skin blood flow (p = 0.55). Endothelial microvascular function was equally impaired among patients with CCC and ischemic cardiomyopathy. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. DRAG REDUCING POLYMER ENCHANCES MICROVASCULAR PERFUSION IN THE TRAUMATIZED BRAIN WITH INTRACRANIAL HYPERTENSION

    PubMed Central

    Bragin, Denis E.; Thomson, Susan; Bragina, Olga; Statom, Gloria; Kameneva, Marina V.; Nemoto, Edwin M.

    2016-01-01

    SUMMARY Current treatments for traumatic brain injury (TBI) have not focused on improving microvascular perfusion. Drag-reducing polymers (DRP), linear, long-chain, blood soluble non-toxic macromolecules, may offer a new approach to improving cerebral perfusion by primary alteration of the fluid dynamic properties of blood. Nanomolar concentrations of DRP have been shown to improve hemodynamics in animal models of ischemic myocardium and limb, but have not yet been studied in the brain. Recently, we demonstrated that that DRP improved microvascular perfusion and tissue oxygenation in a normal rat brain. We hypothesized that DRP could restore microvascular perfusion in hypertensive brain after TBI. Using the in-vivo 2-photon laser scanning microscopy we examined the effect of DRP on microvascular blood flow and tissue oxygenation in hypertensive rat brains with and without TBI. DRP enhanced and restored capillary flow, decreased microvascular shunt flow and, as a result, reduced tissue hypoxia in both un-traumatized and traumatized rat brains at high ICP. Our study suggests that DRP could be an effective treatment for improving microvascular flow in brain ischemia caused by high ICP after TBI. PMID:27165871

  1. Classification of microvascular patterns via cluster analysis reveals their prognostic significance in glioblastoma.

    PubMed

    Chen, Long; Lin, Zhi-Xiong; Lin, Guo-Shi; Zhou, Chang-Fu; Chen, Yu-Peng; Wang, Xing-Fu; Zheng, Zong-Qing

    2015-01-01

    There are limited researches focusing on microvascular patterns (MVPs) in human glioblastoma and their prognostic impact. We evaluated MVPs of 78 glioblastomas by CD34/periodic acid-Schiff dual staining and by cluster analysis of the percentage of microvascular area for distinct microvascular formations. The distribution of 5 types of basic microvascular formations, that is, microvascular sprouting (MS), vascular cluster (VC), vascular garland (VG), glomeruloid vascular proliferation (GVP), and vasculogenic mimicry (VM), was variable. Accordingly, cluster analysis classified MVPs into 2 types: type I MVP displayed prominent MSs and VCs, whereas type II MVP had numerous VGs, GVPs, and VMs. By analyzing the proportion of microvascular area for each type of formation, we determined that glioblastomas with few MSs and VCs had many GVPs and VMs, and vice versa. VG seemed to be a transitional type of formation. In case of type I MVP, expression of Ki-67 and p53 but not MGMT was significantly higher as compared with those of type II MVP (P < .05). Survival analysis showed that the type of MVPs presented as an independent prognostic factor of progression-free survival (PFS) and overall survival (OS) (both P < .001). Type II MVP had a more negative influence on PFS and OS than did type I MVP. We conclude that the heterogeneous MVPs in glioblastoma can be categorized properly by certain histopathologic and statistical analyses and may influence clinical outcome. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Lumbar spinous process splitting decompression provides equivalent outcomes to conventional midline decompression in degenerative lumbar canal stenosis: a prospective, randomized controlled study of 51 patients.

    PubMed

    Rajasekaran, S; Thomas, Ashok; Kanna, Rishi M; Prasad Shetty, Ajoy

    2013-09-15

    Prospective, randomized controlled study. To compare the functional outcomes and extent of paraspinal muscle damage between 2 decompressive techniques for lumbar canal stenosis. Lumbar spinous process splitting decompression (LSPSD) preserves the muscular and liga-mentous attachments of the posterior elements of the spine. It can potentially avoid problems such as paraspinal muscle atrophy and trunk extensor weakness that can occur after conventional midline decompression. However, large series prospective randomized controlled studies are lacking. Patients with lumbar canal stenosis were randomly allocated into 2 groups: LSPSD (28 patients) and conventional midline decompression (23 patients). The differences in operative time, blood loss, time to comfortable mobilization, and hospital stay were studied. Paraspinal muscle damage was assessed by postoperative rise in creatine phosphokinase and C-reactive protein levels. Functional outcome was evaluated at 1 year by Japanese Orthopaedic Association score, neurogenic claudication outcome score, and visual analogue scale for back pain and neurogenic claudication. Fifty-one patients of mean age 56 years were followed-up for a mean 14.2 ± 2.9 months. There were no significant differences in the operative time, blood loss, and hospital stay. Both the groups showed significant improvement in the functional outcome scores at 1 year. Between the 2 groups, the Japanese Orthopaedic Association score, neurogenic claudication outcome score improvement, visual analogue scale for back pain, neurogenic claudication visual analogue scale, and the postoperative changes in serum C-reactive protein and creatine phosphokinase levels did not show any statistically significant difference. On the basis of the Japanese Orthopaedic Association recovery rate, it was found that 73.9% of conventional midline decompression group had good outcomes compared with only 60.7% after LSPSD. The functional outcome scores, back pain, and claudication

  3. A comparison of three induction regimens using succinylcholine, vecuronium, or no muscle relaxant: impact on the intraoperative monitoring of the lateral spread response in hemifacial spasm surgery: study protocol for a randomised controlled trial

    PubMed Central

    2012-01-01

    Background Surgical microvascular decompression (MVD) is the curative treatment for hemifacial spasm (HFS). Monitoring MVD by recording the lateral spread response (LSR) intraoperatively can predict a successful clinical outcome. However, the rate of the LSR varies between trials, and the reason for this variation is unclear. The aim of our trial is to evaluate the rate of the LSR after intubation following treatment with succinylcholine, vecuronium, or no muscle relaxant. Methods and design This trial is a prospective randomised controlled trial of 96 patients with HFS (ASA status I or II) undergoing MVD under general anaesthesia. Patients are randomised to receive succinylcholine, vecuronium, or no muscle relaxant before intubation. Intraoperative LSR will be recorded until dural opening. The primary outcome of this study is the rate of the LSR, and the secondary outcomes are post-intubation pharyngolaryngeal symptoms, the rate of difficult intubations, the rate of adverse haemodynamic events and the relationship between the measurement of LSR or not, and clinical success rates at 30 days after surgery. Discussion This study aims to evaluate the impact of muscle relaxants on the rate of the LSR, and the study may provide evidence supporting the use of muscle relaxants before intubation in patients with HFS undergoing MVD surgery. Trials registration http://www.chictr.org/ ChiCTR-TRC-11001504 Date of registration: 24 June, 2011. The date the first patient was randomised: 30 September, 2011. PMID:22958580

  4. Hemifacial spasm associated with type 1 Chiari malformation: a retrospective study of 13 cases.

    PubMed

    Li, Ning; Zhao, Wei-Guo; Pu, Chun-Hua; Yang, Wen-Lei

    2017-04-01

    Hemifacial spasm (HFS) associated with type 1 Chiari malformation is particularly uncommon and is limited to isolated case report. The aims of this study were to report the clinical correlates of patients who had simultaneously HFS and type 1 Chiari malformation and to present the outcome of these patients treated with microvascular decompression (MVD) surgery. We retrospectively evaluated 13 patients who had simultaneously HFS and type 1 Chiari malformation among 675 HFS patients. Clinical features and radiological findings were collected from each patient and analyzed. All these 13 patients were surgically treated with MVD through retro-mastoid microsurgical approach, and postoperative outcomes were evaluated. A review of literature about this association was also provided. In this study, the frequency of type 1 Chiari malformation in HFS patients was 1.9 %. The clinical profile of this series of patients did not differ from typical form of primary HFS. MVD achieved satisfactory results in 11 patients (85 %) in short- and long-term follow-up. There was no mortality or severe complication occurred postoperatively. Although rare, clinician should be aware of the association of HFS and type 1 Chiari malformation and consider MVD as an effective surgical management.

  5. Complicated Pseudomeningocele Repair After Chiari Decompression: Case Report and Review of the Literature.

    PubMed

    De Tommasi, Claudio; Bond, Aaron E

    2016-04-01

    Pseudomeningocele is a recognised complication after posterior fossa decompression for Chiari malformation. Its management can be challenging and treatment options vary in literature. A difficult-to-treat case of a pseudomeningocele after posterior fossa decompression for a Chiari I malformation is presented. A 34-year-old woman underwent an initial decompression followed by multiple revision surgeries after the development of a symptomatic pseudomeningocele and a low-grade infection. Complications associated with standard treatment modalities, including lumbar drainage and dural repair, are discussed. A review of the existing literature is presented. The reported case ultimately required complete removal of all dural repair materials to eliminate the patient's low-grade infection, a muscular flap, and placement of a ventricular-peritoneal shunt for definitive treatment after a trial of a lumbar drain led to herniation and development of a syrinx. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Decompression sickness and venous gas emboli at 8.3 psia

    NASA Technical Reports Server (NTRS)

    Smead, Kenneth W.; Dixon, Gene A.; Webb, James T.; Krutz, Robert W., Jr.

    1987-01-01

    This study sought to determine the bends risk on decompression from sea level to 8.3 psia. On the basis of several prior studies by NASA and the Air Force, this differential was expected to result in a minimal (about 5 percent) incidence of mild decompression sickness, and may be the pressure of choice for the next-generation NASA extravehicular activity (EVA) pressure suit. Thirty-one volunteer subjects, performing light work characteristic of EVA, were exposed to 8.3 psia pressure altitude for six hours. Limb bends incidence was 3.2 percent, and 25.8 percent of the subjects demonstrated significant intravascular bubbling. Those who bubbled were significantly older than the bubble-free group, but differed in no other aspect. An 8.3 psia advanced pressure suit design was considered insufficient to totally preclude the risk of decompression sickness.

  7. General Purpose Graphics Processing Unit Based High-Rate Rice Decompression and Reed-Solomon Decoding

    SciTech Connect

    Loughry, Thomas A.

    As the volume of data acquired by space-based sensors increases, mission data compression/decompression and forward error correction code processing performance must likewise scale. This competency development effort was explored using the General Purpose Graphics Processing Unit (GPGPU) to accomplish high-rate Rice Decompression and high-rate Reed-Solomon (RS) decoding at the satellite mission ground station. Each algorithm was implemented and benchmarked on a single GPGPU. Distributed processing across one to four GPGPUs was also investigated. The results show that the GPGPU has considerable potential for performing satellite communication Data Signal Processing, with three times or better performance improvements and up to tenmore » times reduction in cost over custom hardware, at least in the case of Rice Decompression and Reed-Solomon Decoding.« less

  8. Decompressive hemicraniectomy in a space-occupying presentation of hemiconvulsion-hemiplegia-epilepsy syndrome.

    PubMed

    Berhouma, Moncef; Chekili, Ridha; Brini, Ines; Kchir, Nidhameddine; Jemel, Hafedh; Bousnina, Souad; Khaldi, Moncef

    2007-12-01

    A case of an acute life-threatening presentation of hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome requiring an urgent decompressive hemicraniectomy is described. A 9 month-old baby had a status epilepticus following a sustained fever, leading to a comatose state and a right pupillary dilatation associated with a left hemiplegia. The MRI showed a swelling right hemisphere with marked temporal herniation. The baby underwent a decompressive right hemicraniectomy with temporal cortical biopsies. The post-operative course was favourable. The histological findings were unspecific, showing a gliotic spongiosis with disseminated granular cells. The post-operative MRI depicted a right hemisphere atrophy. To our knowledge, a space-occupying presentation of HHE syndrome requiring surgical decompression has never been described before while only a few reports dealt with the neuropathological aspects of this syndrome.

  9. Severe capillary leak syndrome after inner ear decompression sickness in a recreational scuba diver.

    PubMed

    Gempp, Emmanuel; Lacroix, Guillaume; Cournac, Jean-Marie; Louge, Pierre

    2013-07-01

    Post-decompression shock with plasma volume deficit is a very rare event that has been observed under extreme conditions of hypobaric and hyperbaric exposure in aviators and professional divers. We report a case of severe hypovolemic shock due to extravasation of plasma in a recreational scuba diver presenting with inner ear decompression sickness. Impaired endothelial function can lead to capillary leak with hemoconcentration and hypotension in severe cases. This report suggests that decompression-induced circulating bubbles may have triggered the endothelial damage, activating the classic inflammatory pathway of increased vascular permeability. This observation highlights the need for an accurate diagnosis of this potentially life-threatening condition at the initial presentation in the Emergency Department after a diving-related injury. An elevated hematocrit in a diver should raise the suspicion for the potential development of capillary leak syndrome requiring specific treatment using albumin infusion as primary fluid replacement. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Towards Probablistic Assessment of Hypobaric Decompression Sickness Treatment

    NASA Technical Reports Server (NTRS)

    Conkin, J.; Abercromby, A. F.; Feiveson, A. H.; Gernhardt, M. L.; Norcross, J. R.; Ploutz-Snyder, R.; Wessel, J. H., III

    2013-01-01

    INTRODUCTION: Pressure, oxygen (O2), and time are the pillars to effective treatment of decompression sickness (DCS). The NASA DCS Treatment Model links a decrease in computed bubble volume to the resolution of a symptom. The decrease in volume is realized in two stages: a) during the Boyle's Law compression and b) during subsequent dissolution of the gas phase by the O2 window. METHODS: The cumulative distribution of 154 symptoms that resolved during repressurization was described with a log-logistic density function of pressure difference (deltaP as psid) associated with symptom resolution and two other explanatory variables. The 154 symptoms originated from 119 cases of DCS during 969 exposures in 47 different altitude tests. RESULTS: The probability of symptom resolution [P(symptom resolution)] = 1 / (1+exp(- (ln(deltaP) - 1.682 + 1.089×AMB - 0.00395×SYMPTOM TIME) / 0.633)), where AMB is 1 when the subject ambulated as part of the altitude exposure or else 0 and SYMPTOM TIME is the elapsed time in min from start of the altitude exposure to recognition of a DCS symptom. The P(symptom resolution) was estimated from computed deltaP from the Tissue Bubble Dynamics Model based on the "effective" Boyle's Law change: P2 - P1 (deltaP, psid) = P1×V1/V2 - P1, where V1 is the computed volume of a spherical bubble in a unit volume of tissue at low pressure P1 and V2 is computed volume after a change to a higher pressure P2. V2 continues to decrease through time at P2, at a faster rate if 100% ground level O2 was breathed. The computed deltaP is the effective treatment pressure at any point in time as if the entire ?deltaP was just from Boyle's Law compression. DISCUSSION: Given the low probability of DCS during extravehicular activity and the prompt treatment of a symptom with options through the model it is likely that the symptom and gas phase will resolve with minimum resources and minimal impact on astronaut health, safety, and productivity.

  11. Deformation localization forming and destruction over a decompression zone.

    NASA Astrophysics Data System (ADS)

    Turuntaev, Sergey; Kondratyev, Viktor

    2017-04-01

    Development of a hydrocarbon field is accompanied by deformation processes in the surrounding rocks. In particular, a subsidence of oil strata cap above a decompression zone near producing wells causes changes in the stress-strain state of the upper rocks. It was shown previously, that the stress spatial changes form a kind of arch structures. The shear displacements along the arch surfaces can occur, and these displacements can cause a collapse of casing or even man-made earthquakes. We present here the results of laboratory simulation of such a phenomenon. A laboratory setup was made in the form of narrow box 30x30x5 cm3 in size with a hole (0.6 cm in diameter) in its bottom. As a model of porous strata, a foam-rubber layer of 4.0 -10.5cm in thick was used, which was saturated with water. The foam was sealed to the bottom of the box; the upper part of the box was filled by the dry sand. The sand was separated from the foam by thin polyethylene film to prevent the sand wetting. For visualization the sand deformations, the front wall of the box was made transparent and the sand was marked by horizontal strips of the colored sand. In the experiments, the water was pumped out the foam layer through the bottom hole. After pumping-out 50 ml of the water, the localization of sand deformations above the sink hole became noticeable; after pumping-out 100 ml of the water, the localized deformation forms an arch. At the same time, there was no displacement on the upper surface of the sand. To amplify the localization effect, the foam was additionally squeezed locally. In this case, three surfaces of the localized deformation appeared in the sand. The vertical displacements decreased essentially with height, but they reached the upper layers of the sand. An influence of vibration on arches forming was investigated. Several types of vibrators were used, they were placed inside the sand or on the front side of the box. Resulting accelerations were measured by the

  12. Experimental Evidence of Low Density Liquid Water under Decompression

    NASA Astrophysics Data System (ADS)

    Shen, G.; Lin, C.; Sinogeikin, S. V.; Smith, J.

    2017-12-01

    Water is not only the most important substance for life, but also plays important roles in liquid science for its anomalous properties. It has been widely accepted that water's anomalies are not a result of simple thermal fluctuation, but are connected to the formation of various structural aggregates in the hydrogen bonding network. Among several proposed scenarios, one model of fluctuations between two different liquids has gradually gained traction. These two liquids are referred to as a low-density liquid (LDL) and a high-density liquid (HDL) with a coexistence line in the deeply supercooled regime at elevated pressure. The LDL-HDL transition ends with decreasing pressure at a liquid-liquid critical point (LLCP) with its Widom line extending to low pressures. Above the Widom line lies mostly HDL which is favored by entropy, while LDL, mostly lying below the Widom line, is favored by enthalpy in the tetrahedral hydrogen bonding network. The origin of water's anomalies can then be explained by the increase in structural fluctuations, as water is cooled down to deeply supercooled temperatures approaching the Widom line. Because both the LLCP and the LDL-HDL transition line lie in water's "no man's land" between the homogeneous nucleation temperature (TH, 232 K) and the crystallization temperature (TX, 150 K), the success of experiments exploring this region has been limited thus far. Using a rapid decompression technique integrated with in situ x-ray diffraction, we observe that a high-pressure ice phase transforms to a low-density noncrystalline (LDN) form upon rapid release of pressure at temperatures of 140-165K. The LDN subsequently crystallizes into ice-Ic through a diffusion-controlled process. The change in crystallization rate with temperature indicates that the LDN is a LDL with its tetrahedrally-coordinated network fully developed and clearly linked to low-density amorphous ices. The observation of the tetrahedral LDL supports the two-liquid model for

  13. Outcomes of decompressive craniectomy in patients after traumatic brain injury.

    PubMed

    Nambiar, Mithun; MacIsaac, Christopher; Grabinski, Rafal; Liew, Danny; Kavar, Bhadrakant

    2015-06-01

    Traumatic brain injury (TBI) can result in cerebral oedema and vascular changes resulting in an increase in intracranial pressure (ICP), which can lead to further secondary damage. Decompressive craniectomy (DC) is a surgical option in the management of ICP. We aimed to investigate outcomes of DC after TBI. We performed a retrospective audit of 57 adult patients (aged > 15 years) who underwent DC after TBI, at the Royal Melbourne Hospital from 1 January 2005 to 30 June 2011. Our functional outcome measure was the Extended Glasgow Outcome Scale (GOSE). Patients had a median age of 30 years (range, 17- 73 years). The hospital mortality rate was 47% (27 patients). A higher postoperative median ICP was the most significant predictor of hospital mortality (OR, 1.1; 95% CI, 1-1.3). There was a mean decrease of 7.7mmHg in ICP between the mean preoperative and postoperative ICP values (95% CI, - 10.5 to - 5.0mmHg). There was a mean decrease of 3.5mmHg in the mean cerebral perfusion pressure (CPP) from preoperative to postoperative CPP values (95% CI, - 6.2 to - 0.8mmHg). At the 6-month follow-up, a poor outcome (GOSE score, 1-4) was seen in 39 patients (68%), while a good outcome (GOSE score, 5- 8) was noted in 15 patients (26%). A high APACHE II score on admission was the most significant predictor of a worse GOSE score at 6 months (OR, 1.3; 95% CI, 1.1-1.5). Analysis of the APACHE II and IMPACT scores as models for predicting mortality at 6 months showed an area under the curve (AUC) of 0.792 and 0.805, respectively, and for predicting poor outcome at 6 months, showed an AUC of 0.862 and 0.883, respectively. DC decreased ICP postoperatively. The IMPACT and APACHE II scores are good models for prediction of death and poor outcome at 6 months.

  14. Dibutyryl cAMP effects on thromboxane and leukotriene production in decompression-induced lung injury

    NASA Technical Reports Server (NTRS)

    Little, T. M.; Butler, B. D.

    1997-01-01

    Decompression-induced venous bubble formation has been linked to increased neutrophil counts, endothelial cell injury, release of vasoactive eicosanoids, and increased vascular membrane permeability. These actions may account for inflammatory responses and edema formation. Increasing the intracellular cAMP has been shown to decrease eicosanoid production and edema formation in various models of lung injury. Reduction of decompression-induced inflammatory responses was evaluated in decompressed rats pretreated with saline (controls) or dibutyryl cAMP (DBcAMP, an analog of cAMP). After pretreatment, rats were exposed to either 616 kPa for 120 min or 683 kPa for 60 min. The observed increases in extravascular lung water ratios (pulmonary edema), bronchoalveolar lavage, and pleural protein in the saline control group (683 kPa) were not evident with DBcAMP treatment. DBcAMP pretreatment effects were also seen with the white blood cell counts and the percent of neutrophils in the bronchoalveolar lavage. Urinary levels of thromboxane B2, 11-dehydrothromboxane B2, and leukotriene E4 were significantly increased with the 683 kPa saline control decompression exposure. DBcAMP reduced the decompression-induced leukotriene E4 production in the urine. Plasma levels of thromboxane B2, 11-dehydrothromboxane B2, and leukotriene E4 were increased with the 683-kPa exposure groups. DBcAMP treatment did not affect these changes. The 11-dehydrothromboxane B2 and leukotriene E4 levels in the bronchoalveolar lavage were increased with the 683 kPa exposure and were reduced with the DBcAMP treatment. Our results indicate that DBcAMP has the capability to reduce eicosanoid production and limit membrane permeability and subsequent edema formation in rats experiencing decompression sickness.

  15. Nerve Decompression Surgery After Total Hip Arthroplasty: What Are the Outcomes?

    PubMed

    Chughtai, Morad; Khlopas, Anton; Gwam, Chukwuwieke U; Elmallah, Randa K; Thomas, Melbin; Nace, James; Mont, Michael A

    2017-04-01

    The purpose of our study was to compare (1) muscle strength; (2) pain; (3) sensation; (4) various outcome measurement scales between post-total hip arthroplasty (THA) patients who had a sciatic nerve injury and did or did not receive decompression surgery for this condition; and (5) to compare these findings with current literature. Nineteen patients who had nerve injury after THA were reviewed. Patients were stratified into those who had a nerve decompression (n = 12), and those who had not (n = 7). Motor strength was evaluated using the Muscle Strength Testing Scale. Pain was evaluated by using the visual analogue scale. Systematic literature search was performed to compare the findings of this study with others currently published. The decompression group had a significant improvement in motor strength and the visual analog scale scores as compared with nonoperative group. Patients in decompression group had a significant larger increase in the mean Harris hip score and University of California Los Angeles score. There was no significant difference in the increase of Short Form-36 physical and mental scores between the 2 groups. Literature review for nonoperative management yielded 5 studies (93 patients), with 33% improvement. There were 7 studies (81 patients) on nerve decompression surgery, with 75% improvement. This study demonstrates the benefits of nerve decompression surgery in patients who had sciatic nerve injury after THA, as evidenced by results of standardized outcome measurement scales. It is possible to achieve improvements in terms of strength, pain, and clinical outcomes. Comparative studies with larger cohorts are needed to fully assess the best candidates for this procedure. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Magma decompression rates during explosive eruptions of Kīlauea volcano, Hawaii, recorded by melt embayments

    USGS Publications Warehouse

    Ferguson, David J.; Gonnermann, Helge M.; Ruprecht, Philipp; Plank, Terry; Hauri, Erik H.; Houghton, Bruce F.; Swanson, Donald A.

    2016-01-01

    The decompression rate of magma as it ascends during volcanic eruptions is an important but poorly constrained parameter that controls many of the processes that influence eruptive behavior. In this study, we quantify decompression rates for basaltic magmas using volatile diffusion in olivine-hosted melt tubes (embayments) for three contrasting eruptions of Kīlauea volcano, Hawaii. Incomplete exsolution of H2O, CO2, and S from the embayment melts during eruptive ascent creates diffusion profiles that can be measured using microanalytical techniques, and then modeled to infer the average decompression rate. We obtain average rates of ~0.05–0.45 MPa s−1 for eruptions ranging from Hawaiian style fountains to basaltic subplinian, with the more intense eruptions having higher rates. The ascent timescales for these magmas vary from around ~5 to ~36 min from depths of ~2 to ~4 km, respectively. Decompression-exsolution models based on the embayment data also allow for an estimate of the mass fraction of pre-existing exsolved volatiles within the magma body. In the eruptions studied, this varies from 0.1 to 3.2 wt% but does not appear to be the key control on eruptive intensity. Our results do not support a direct link between the concentration of pre-eruptive volatiles and eruptive intensity; rather, they suggest that for these eruptions, decompression rates are proportional to independent estimates of mass discharge rate. Although the intensity of eruptions is defined by the discharge rate, based on the currently available dataset of embayment analyses, it does not appear to scale linearly with average decompression rate. This study demonstrates the utility of the embayment method for providing quantitative constraints on magma ascent during explosive basaltic eruptions.

  17. The physiological kinetics of nitrogen and the prevention of decompression sickness.

    PubMed

    Doolette, D J; Mitchell, S J

    2001-01-01

    Decompression sickness (DCS) is a potentially crippling disease caused by intracorporeal bubble formation during or after decompression from a compressed gas underwater dive. Bubbles most commonly evolve from dissolved inert gas accumulated during the exposure to increased ambient pressure. Most diving is performed breathing air, and the inert gas of interest is nitrogen. Divers use algorithms based on nitrogen kinetic models to plan the duration and degree of exposure to increased ambient pressure and to control their ascent rate. However, even correct execution of dives planned using such algorithms often results in bubble formation and may result in DCS. This reflects the importance of idiosyncratic host factors that are difficult to model, and deficiencies in current nitrogen kinetic models. Models describing the exchange of nitrogen between tissues and blood may be based on distributed capillary units or lumped compartments, either of which may be perfusion- or diffusion-limited. However, such simplistic models are usually poor predictors of experimental nitrogen kinetics at the organ or tissue level, probably because they fail to account for factors such as heterogeneity in both tissue composition and blood perfusion and non-capillary exchange mechanisms. The modelling of safe decompression procedures is further complicated by incomplete understanding of the processes that determine bubble formation. Moreover, any formation of bubbles during decompression alters subsequent nitrogen kinetics. Although these factors mandate complex resolutions to account for the interaction between dissolved nitrogen kinetics and bubble formation and growth, most decompression schedules are based on relatively simple perfusion-limited lumped compartment models of blood: tissue nitrogen exchange. Not surprisingly, all models inevitably require empirical adjustment based on outcomes in the field. Improvements in the predictive power of decompression calculations are being

  18. Patient-specific core decompression surgery for early-stage ischemic necrosis of the femoral head

    PubMed Central

    Wang, Wei; Hu, Wei; Yang, Pei; Dang, Xiao Qian; Li, Xiao Hui; Wang, Kun Zheng

    2017-01-01

    Introduction Core decompression is an efficient treatment for early stage ischemic necrosis of the femoral head. In conventional procedures, the pre-operative X-ray only shows one plane of the ischemic area, which often results in inaccurate drilling. This paper introduces a new method that uses computer-assisted technology and rapid prototyping to enhance drilling accuracy during core decompression surgeries and presents a validation study of cadaveric tests. Methods Twelve cadaveric human femurs were used to simulate early-stage ischemic necrosis. The core decompression target at the anterolateral femoral head was simulated using an embedded glass ball (target). Three positioning Kirschner wires were drilled into the top and bottom of the large rotor. The specimen was then subjected to computed tomography (CT). A CT image of the specimen was imported into the Mimics software to construct a three-dimensional model including the target. The best core decompression channel was then designed using the 3D model. A navigational template for the specimen was designed using the Pro/E software and manufactured by rapid prototyping technology to guide the drilling channel. The specimen-specific navigation template was installed on the specimen using positioning Kirschner wires. Drilling was performed using a guide needle through the guiding hole on the templates. The distance between the end point of the guide needle and the target was measured to validate the patient-specific surgical accuracy. Results The average distance between the tip of the guide needle drilled through the guiding template and the target was 1.92±0.071 mm. Conclusions Core decompression using a computer-rapid prototyping template is a reliable and accurate technique that could provide a new method of precision decompression for early-stage ischemic necrosis. PMID:28464029

  19. Patient-specific core decompression surgery for early-stage ischemic necrosis of the femoral head.

    PubMed

    Wang, Wei; Hu, Wei; Yang, Pei; Dang, Xiao Qian; Li, Xiao Hui; Wang, Kun Zheng

    2017-01-01

    Core decompression is an efficient treatment for early stage ischemic necrosis of the femoral head. In conventional procedures, the pre-operative X-ray only shows one plane of the ischemic area, which often results in inaccurate drilling. This paper introduces a new method that uses computer-assisted technology and rapid prototyping to enhance drilling accuracy during core decompression surgeries and presents a validation study of cadaveric tests. Twelve cadaveric human femurs were used to simulate early-stage ischemic necrosis. The core decompression target at the anterolateral femoral head was simulated using an embedded glass ball (target). Three positioning Kirschner wires were drilled into the top and bottom of the large rotor. The specimen was then subjected to computed tomography (CT). A CT image of the specimen was imported into the Mimics software to construct a three-dimensional model including the target. The best core decompression channel was then designed using the 3D model. A navigational template for the specimen was designed using the Pro/E software and manufactured by rapid prototyping technology to guide the drilling channel. The specimen-specific navigation template was installed on the specimen using positioning Kirschner wires. Drilling was performed using a guide needle through the guiding hole on the templates. The distance between the end point of the guide needle and the target was measured to validate the patient-specific surgical accuracy. The average distance between the tip of the guide needle drilled through the guiding template and the target was 1.92±0.071 mm. Core decompression using a computer-rapid prototyping template is a reliable and accurate technique that could provide a new method of precision decompression for early-stage ischemic necrosis.

  20. Technique for Mini-open Decompression of Chiari Type I Malformation in Adults.

    PubMed

    Pakzaban, Peyman

    2017-08-01

    The technique for decompression of Chiari type I malformation relies on open exposure of craniocervical junction for suboccipital craniectomy and upper cervical laminectomy with or without duraplasty. There is no detailed technical report of a minimally invasive approach for Chiari decompression in adults. To describe a mini-open technique for decompression of Chiari type I malformation (including duraplasty) in adults. Six consecutive adult patients with symptomatic Chiari type I malformation underwent decompression through a 3 to 4 cm midline incision via a speculum retractor. All patients underwent a limited suboccipital craniectomy and C1 laminectomy with an ultrasonic bone scalpel. All patients underwent duraplasty with a synthetic dural substitute. In the 2 patients with syringomyelia, the arachnoid was opened and intradural dissection was carried out. In the remaining 4 patients, the arachnoid was left intact. All operations were completed successfully through the mini-open exposure. Mean surgery time, blood loss, and length of stay were 114 min, 55 mL, and 1.3 days, respectively. Mean follow-up was 13.2 months (range 9-18). All patients had excellent clinical outcomes as defined by scores of 15 (3 patients) or 16 (3 patients) on Chicago Chiari Outcome Scale. There were no neurological complications or cerebrospinal fluid leaks. Postop computed tomography revealed good boney decompression. In the 2 patients with syringomyelia, MRI at 6 months revealed resolution of the syrinx. Decompression of Chiari type I malformation in adults can be performed safely and effectively through the mini-open exposure described in this report. Copyright © 2017 by the Congress of Neurological Surgeons

  1. Magma decompression rates during explosive eruptions of Kīlauea volcano, Hawaii, recorded by melt embayments

    NASA Astrophysics Data System (ADS)

    Ferguson, David J.; Gonnermann, Helge M.; Ruprecht, Philipp; Plank, Terry; Hauri, Erik H.; Houghton, Bruce F.; Swanson, Donald A.

    2016-10-01

    The decompression rate of magma as it ascends during volcanic eruptions is an important but poorly constrained parameter that controls many of the processes that influence eruptive behavior. In this study, we quantify decompression rates for basaltic magmas using volatile diffusion in olivine-hosted melt tubes (embayments) for three contrasting eruptions of Kīlauea volcano, Hawaii. Incomplete exsolution of H2O, CO2, and S from the embayment melts during eruptive ascent creates diffusion profiles that can be measured using microanalytical techniques, and then modeled to infer the average decompression rate. We obtain average rates of ~0.05-0.45 MPa s-1 for eruptions ranging from Hawaiian style fountains to basaltic subplinian, with the more intense eruptions having higher rates. The ascent timescales for these magmas vary from around ~5 to ~36 min from depths of ~2 to ~4 km, respectively. Decompression-exsolution models based on the embayment data also allow for an estimate of the mass fraction of pre-existing exsolved volatiles within the magma body. In the eruptions studied, this varies from 0.1 to 3.2 wt% but does not appear to be the key control on eruptive intensity. Our results do not support a direct link between the concentration of pre-eruptive volatiles and eruptive intensity; rather, they suggest that for these eruptions, decompression rates are proportional to independent estimates of mass discharge rate. Although the intensity of eruptions is defined by the discharge rate, based on the currently available dataset of embayment analyses, it does not appear to scale linearly with average decompression rate. This study demonstrates the utility of the embayment method for providing quantitative constraints on magma ascent during explosive basaltic eruptions.

  2. Diabetes Mellitus-Induced Microvascular Destabilization in the Myocardium.

    PubMed

    Hinkel, Rabea; Howe, Andrea; Renner, Simone; Ng, Judy; Lee, Seungmin; Klett, Katharina; Kaczmarek, Veronika; Moretti, Alessandra; Laugwitz, Karl-Ludwig; Skroblin, Philipp; Mayr, Manuel; Milting, Hendrik; Dendorfer, Andreas; Reichart, Bruno; Wolf, Eckhard; Kupatt, Christian

    2017-01-17

    Diabetes mellitus causes microcirculatory rarefaction and may impair the responsiveness of ischemic myocardium to proangiogenic factors. This study sought to determine whether microvascular destabilization affects organ function and therapeutic neovascularization in diabetes mellitus. The authors obtained myocardial samples from patients with end-stage heart failure at time of transplant, with or without diabetes mellitus. Diabetic (db) and wild-type (wt) pigs were used to analyze myocardial vascularization and function. Chronic ischemia was induced percutaneously (day 0) in the circumflex artery. At day 28, recombinant adeno-associated virus (rAAV) (5 × 10 12 viral particles encoding vascular endothelial growth factor-A [VEGF-A] or thymosin beta 4 [Tβ4]) was applied regionally. CD31+ capillaries per high power field (c/hpf) and NG2+ pericyte coverage were analyzed. Global myocardial function (ejection fraction [EF] and left ventricular end-diastolic pressure) was assessed at days 28 and 56. Diabetic human myocardial explants revealed capillary rarefaction and pericyte loss compared to nondiabetic explants. Hyperglycemia in db pigs, even without ischemia, induced capillary rarefaction in the myocardium (163 ± 14 c/hpf in db vs. 234 ± 8 c/hpf in wt hearts; p < 0.005), concomitant with a distinct loss of EF (44.9% vs. 53.4% in nondiabetic controls; p < 0.05). Capillary density further decreased in chronic ischemic hearts, as did EF (both p < 0.05). Treatment with rAAV.Tβ4 enhanced capillary density and maturation in db hearts less efficiently than in wt hearts, similar to collateral growth. rAAV.VEGF-A, though stimulating angiogenesis, induced neither pericyte recruitment nor collateral growth. As a result, rAAV.Tβ4 but not rAAV.VEGF-A improved EF in db hearts (34.5 ± 1.4%), but less so than in wt hearts (44.8 ± 1.5%). Diabetes mellitus destabilized microvascular vessels of the heart, affecting the amplitude of therapeutic neovascularization via r

  3. In vitro analysis of human periodontal microvascular endothelial cells.

    PubMed

    Tsubokawa, Mizuki; Sato, Soh

    2014-08-01

    Endothelial cells (ECs) participate in key aspects of vascular biology, such as maintenance of capillary permeability, initiation of coagulation, and regulation of inflammation. According to previous reports, ECs have revealed highly specific characteristics depending on the organs and tissues. However, some reports have described the characteristics of the capillaries formed by human periodontal ECs. Therefore, the aim of the present study is to examine the functional characteristics of the periodontal microvascular ECs in vitro. Human periodontal ligament-endothelial cells (HPDL-ECs) and human gingiva-endothelial cells (HG-ECs) were isolated by immunoprecipitation with magnetic beads conjugated to a monoclonal anti-CD31 antibody. The isolated HPDL-ECs and HG-ECs were characterized to definitively demonstrate that these cell cultures represented pure ECs. Human umbilical-vein ECs and human dermal microvascular ECs were used for comparison. These cells were compared according to the proliferation potential, the formation of capillary-like tubes, the transendothelial electric resistance (TEER), and the expression of tight junction proteins. HPDL-ECs and HG-ECs with characteristic cobblestone monolayer morphology were obtained, as determined by light microscopy at confluence. Furthermore, the HPDL-ECs and HG-ECs expressed the EC markers platelet endothelial cell adhesion molecule-1 (also known as CD31), von Willebrand factor, and Ulex europaeus agglutinin 1, and the cells stained strongly positive for CD31 and CD309. In addition, the HPDL-ECs and HG-ECs were observed to form capillary-like tubes, and they demonstrated uptake of acetylated low-density lipoprotein. Functional analyses of the HPDL-ECs and HG-ECs showed that, compared to the control cells, tube formation persisted for only a brief period of time, and TEER was substantially reduced at confluence. Furthermore, the cells exhibited delocalization of zonula occludens-1 and occludin at cell-cell contact sites

  4. Hazards of high altitude decompression sickness during falls in barometric pressure from 1 atm to a fraction thereof

    NASA Technical Reports Server (NTRS)

    Genin, A. M.

    1980-01-01

    Various tests related to studies concerning the effects of decompression sicknesses at varying pressure levels and physical activity are described. The tests indicate that there are no guarantees of freedom from decompression sicknesses when man transitions from a normally oxygenated normobaric nitrogen-oxygen atmosphere into an environment having a 0.4 atm or lower pressure and he is performing physical work.

  5. Continuous decompression of unicameral bone cyst with cannulated screws: a comparative study.

    PubMed

    Brecelj, Janez; Suhodolcan, Lovro

    2007-09-01

    We determined the role of mechanical decompression in the resolution of unicameral bone cyst. A total of 69 children with unicameral bone cysts were treated either by (i) open curettage and bone grafting, (ii) steroid injection or (iii) cannulated screw insertion. During a mean follow-up of 69 months (range, 12-58), the cysts were evaluated by radiological criteria. The healing rates in the three groups were 25, 12 and 29% after the first treatment, and a further 50, 19 and 65% after the second. The study has demonstrated the advantages of the decompression technique for unicameral bone cysts over other treatment modalities studied.

  6. Image compression/decompression based on mathematical transform, reduction/expansion, and image sharpening

    DOEpatents

    Fu, Chi-Yung; Petrich, Loren I.

    1997-01-01

    An image represented in a first image array of pixels is first decimated in two dimensions before being compressed by a predefined compression algorithm such as JPEG. Another possible predefined compression algorithm can involve a wavelet technique. The compressed, reduced image is then transmitted over the limited bandwidth transmission medium, and the transmitted image is decompressed using an algorithm which is an inverse of the predefined compression algorithm (such as reverse JPEG). The decompressed, reduced image is then interpolated back to its original array size. Edges (contours) in the image are then sharpened to enhance the perceptual quality of the reconstructed image. Specific sharpening techniques are described.

  7. Statistical comparison of pooled nitrogen washout data of various altitude decompression response groups

    NASA Technical Reports Server (NTRS)

    Edwards, B. F.; Waligora, J. M.; Horrigan, D. J., Jr.

    1985-01-01

    This analysis was done to determine whether various decompression response groups could be characterized by the pooled nitrogen (N2) washout profiles of the group members, pooling individual washout profiles provided a smooth time dependent function of means representative of the decompression response group. No statistically significant differences were detected. The statistical comparisons of the profiles were performed by means of univariate weighted t-test at each 5 minute profile point, and with levels of significance of 5 and 10 percent. The estimated powers of the tests (i.e., probabilities) to detect the observed differences in the pooled profiles were of the order of 8 to 30 percent.

  8. Decompression sickness in a vegetarian diver: are vegetarian divers at risk? A case report.

    PubMed

    van Hulst, Robert A; van der Kamp, Wim

    2010-01-01

    We present a case of a diver who suffered decompression sickness (DCS), but who also was a strict vegetarian for more than 10 years. He presented with symptoms of tingling of both feet and left hand, weakness in both legs and sensory deficits for vibration and propriocepsis after two deep dives with decompression. The initial clinical features of this case were most consistent with DCS, possibly because of a vulnerable spinal cord due to cobalamin deficiency neuropathy. This case illustrates the similarities between DCS and a clinically defined vitamin B12 deficiency. The pathophysiology of vitamin B12 deficiency and common pathology and symptoms of DCS are reviewed.

  9. Image compression/decompression based on mathematical transform, reduction/expansion, and image sharpening

    DOEpatents

    Fu, C.Y.; Petrich, L.I.

    1997-12-30

    An image represented in a first image array of pixels is first decimated in two dimensions before being compressed by a predefined compression algorithm such as JPEG. Another possible predefined compression algorithm can involve a wavelet technique. The compressed, reduced image is then transmitted over the limited bandwidth transmission medium, and the transmitted image is decompressed using an algorithm which is an inverse of the predefined compression algorithm (such as reverse JPEG). The decompressed, reduced image is then interpolated back to its original array size. Edges (contours) in the image are then sharpened to enhance the perceptual quality of the reconstructed image. Specific sharpening techniques are described. 22 figs.

  10. Blood biochemical and cellular changes during a decompression procedure involving eight hours of oxygen prebreathing

    NASA Technical Reports Server (NTRS)

    Jauchem, J. R.

    1989-01-01

    Chemical and cellular parameters were measured in human subjects before and after exposure to a decompression schedule involving 8 h of oxygen prebreathing. The exposure was designed to simulate space-flight extravehicular activity (EVA) for 6 h. Several statistically significant changes in blood parameters were observed following the exposure: increases in calcium, magnesium, osmolality, low-density lipoprotein cholesterol, monocytes, and prothrombin time, and decreases in chloride, creatine phosphokinase and eosinophils. The changes, however, were small in magnitude and blood factor levels remained within normal clinical ranges. Thus, the decompression profile used in this study is not likely to result in blood changes that would pose a threat to astronauts during EVA.

  11. The robotic ENT microsurgery system: A novel robotic platform for microvascular surgery.

    PubMed

    Feng, Allen L; Razavi, Christopher R; Lakshminarayanan, Pranav; Ashai, Zaid; Olds, Kevin; Balicki, Marcin; Gooi, Zhen; Day, Andrew T; Taylor, Russell H; Richmon, Jeremy D

    2017-11-01

    Assess the feasibility of a novel robotic platform for use in microvascular surgery. Prospective feasibility study. Robotics laboratory. The Robotic ENT (Ear, Nose, and Throat) Microsurgery System (REMS) (Galen Robotics, Inc., Sunnyvale, CA) is a robotic arm that stabilizes a surgeon's instrument, allowing precise, tremor-free movement. Six microvascular naïve medical students and one microvascular expert performed microvascular anastomosis of a chicken ischiatic artery, with and without the REMS. Trials were blindly graded by seven microvascular surgeons using a microvascular tremor scale (MTS) based on instrument tip movement as a function of vessel width. Time to completion (TTC) was measured, and an exit survey assessed participants' experience. The interrater reliability of the MTS was calculated. For microvascular-naïve participants, the mean MTS score for REMS-assisted trials was 0.72 (95% confidence interval [CI] 0.64-1.07) and 2.40 (95% CI 2.12-2.69) for freehand (P < 0.001). The mean TTC was 1,265 seconds for REMS-assisted trials and 1,320 seconds for freehand (P > 0.05). For the microvascular expert, the mean REMS-assisted MTS score was 0.71 (95% CI 0.15-1.27) and 0.86 (95% CI 0.35-1.37) for freehand (P > 0.05). TTC was 353 seconds for the REMS-assisted trial and 299 seconds for freehand. All participants thought the REMS was more accurate and improved instrument handling and stability. The intraclass correlation coefficient for MTS ratings was 0.914 (95% CI 0.823-0.968) for consistency and 0.901 (95% CI 0.795-0.963) for absolute value. The REMS is a feasible adjunct for microvascular surgery and a potential teaching tool capable of reducing tremor in novice users. Furthermore, the MTS is a feasible grading system for assessing microvascular tremor. NA. Laryngoscope, 127:2495-2500, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  12. A New Era in Diagnostic Ultrasound, Superb Microvascular Imaging: Preliminary Results in Pediatric Hepato-Gastrointestinal Disorders.

    PubMed

    Ohno, Yasuharu; Fujimoto, Tamotsu; Shibata, Yukari

    2017-02-01

    Introduction  Superb microvascular imaging is a new ultrasound image processing technique that uses advanced clutter suppression to extract flow signals from vessels and which helps us visualize very small vascular structures that were not previously visible without the use of a contrast agent. We herein analyzed the usefulness of superb microvascular imaging in the diagnosis of hepato-gastrointestinal disorders in pediatric patients. Materials and Methods  Fifty-six pediatric patients who underwent a total of 81 superb microvascular imaging examinations with an Aplio 300 ultrasound system (Toshiba Medical Systems, Tokyo, Japan) were enrolled in this study. The subjects underwent conventional ultrasound examinations, including Doppler imaging followed by superb microvascular imaging. The superb microvascular imaging findings and standard imaging were compared. All of the examinations were performed without sedation. Results  The average age of the patients (male, n  = 38; female, n  = 18) was 4 years. The clinical diagnoses included hepatobiliary disorders ( n  = 29), acute appendicitis ( n  = 10), and other intestinal disorders ( n  = 17). The target organs for superb microvascular imaging were the liver, appendix, rectum, intestine, gallbladder, and lymph node. In most of the patients, superb microvascular imaging achieved the excellent visualization of microvascular structures, revealing abnormal vasculature in 21 out of 46 (45.7%) examinations of the liver, 9/9 (100%) examinations of the appendix, 0/11 (0%) examinations of the rectum, 9/11 (81.8%) examinations of the intestine, 0/1 (0%) examinations of the gallbladder, and 3/3 (100%) examinations of the lymph nodes. Superb microvascular imaging was superior to Doppler imaging for depicting the microvascular structures. Conclusions  Superb microvascular imaging is especially useful for depicting the microvascular flow and can aid in the diagnosis and treatment planning for pediatric

  13. Normal Muscle Oxygen Consumption and Fatigability in Sickle Cell Patients Despite Reduced Microvascular Oxygenation and Hemorheological Abnormalities

    PubMed Central

    Waltz, Xavier; Pichon, Aurélien; Lemonne, Nathalie; Mougenel, Danièle; Lalanne-Mistrih, Marie-Laure; Lamarre, Yann; Tarer, Vanessa; Tressières, Benoit; Etienne-Julan, Maryse; Hardy-Dessources, Marie-Dominique; Hue, Olivier; Connes, Philippe

    2012-01-01

    Background/Aim Although it has been hypothesized that muscle metabolism and fatigability could be impaired in sickle cell patients, no study has addressed this issue. Methods We compared muscle metabolism and function (muscle microvascular oxygenation, microvascular blood flow, muscle oxygen consumption and muscle microvascular oxygenation variability, which reflects vasomotion activity, maximal muscle force and local muscle fatigability) and the hemorheological profile at rest between 16 healthy subjects (AA), 20 sickle cell-hemoglobin C disease (SC) patients and 16 sickle cell anemia (SS) patients. Results Muscle microvascular oxygenation was reduced in SS patients compared to the SC and AA groups and this reduction was not related to hemorhelogical abnormalities. No difference was observed between the three groups for oxygen consumption and vasomotion activity. Muscle microvascular blood flow was higher in SS patients compared to the AA group, and tended to be higher compared to the SC group. Multivariate analysis revealed that muscle oxygen consumption was independently associated with muscle microvascular blood flow in the two sickle cell groups (SC and SS). Finally, despite reduced muscle force in sickle cell patients, their local muscle fatigability was similar to that of the healthy subjects. Conclusions Sickle cell patients have normal resting muscle oxygen consumption and fatigability despite hemorheological alterations and, for SS patients only, reduced muscle microvascular oxygenation and increased microvascular blood flow. Two alternative mechanisms can be proposed for SS patients: 1) the increased muscle microvascular blood flow is a way to compensate for the lower muscle microvascular oxygenation to maintain muscle oxygen consumption to normal values or 2) the reduced microvascular oxygenation coupled with a normal resting muscle oxygen consumption could indicate that there is slight hypoxia within the muscle which is not sufficient to limit

  14. Normal muscle oxygen consumption and fatigability in sickle cell patients despite reduced microvascular oxygenation and hemorheological abnormalities.

    PubMed

    Waltz, Xavier; Pichon, Aurélien; Lemonne, Nathalie; Mougenel, Danièle; Lalanne-Mistrih, Marie-Laure; Lamarre, Yann; Tarer, Vanessa; Tressières, Benoit; Etienne-Julan, Maryse; Hardy-Dessources, Marie-Dominique; Hue, Olivier; Connes, Philippe

    2012-01-01

    Although it has been hypothesized that muscle metabolism and fatigability could be impaired in sickle cell patients, no study has addressed this issue. We compared muscle metabolism and function (muscle microvascular oxygenation, microvascular blood flow, muscle oxygen consumption and muscle microvascular oxygenation variability, which reflects vasomotion activity, maximal muscle force and local muscle fatigability) and the hemorheological profile at rest between 16 healthy subjects (AA), 20 sickle cell-hemoglobin C disease (SC) patients and 16 sickle cell anemia (SS) patients. Muscle microvascular oxygenation was reduced in SS patients compared to the SC and AA groups and this reduction was not related to hemorhelogical abnormalities. No difference was observed between the three groups for oxygen consumption and vasomotion activity. Muscle microvascular blood flow was higher in SS patients compared to the AA group, and tended to be higher compared to the SC group. Multivariate analysis revealed that muscle oxygen consumption was independently associated with muscle microvascular blood flow in the two sickle cell groups (SC and SS). Finally, despite reduced muscle force in sickle cell patients, their local muscle fatigability was similar to that of the healthy subjects. Sickle cell patients have normal resting muscle oxygen consumption and fatigability despite hemorheological alterations and, for SS patients only, reduced muscle microvascular oxygenation and increased microvascular blood flow. Two alternative mechanisms can be proposed for SS patients: 1) the increased muscle microvascular blood flow is a way to compensate for the lower muscle microvascular oxygenation to maintain muscle oxygen consumption to normal values or 2) the reduced microvascular oxygenation coupled with a normal resting muscle oxygen consumption could indicate that there is slight hypoxia within the muscle which is not sufficient to limit mitochondrial respiration but increases muscle

  15. Review: Cerebral microvascular pathology in aging and neurodegeneration

    PubMed Central

    Brown, William R.; Thore, Clara R.

    2010-01-01

    This review of age-related brain microvascular pathologies focuses on topics studied by this laboratory, including anatomy of the blood supply, tortuous vessels, venous collagenosis, capillary remnants, vascular density, and microembolic brain injury. Our studies feature thick sections, large blocks embedded in celloidin, and vascular staining by alkaline phosphatase (AP). This permits study of the vascular network in three dimensions, and the differentiation of afferent from efferent vessels. Current evidence suggests that there is decreased vascular density in aging, Alzheimer’s disease (AD), and leukoaraiosis (LA), and cerebrovascular dysfunction precedes and accompanies cognitive dysfunction and neurodegeneration. A decline in cerebrovascular angiogenesis may inhibit recovery from hypoxia-induced capillary loss. Cerebral blood flow (CBF) is inhibited by tortuous arterioles and deposition of excessive collagen in veins and venules. Misery perfusion due to capillary loss appears to occur before cell loss in LA, and CBF is also reduced in the normal-appearing white matter. Hypoperfusion occurs early in AD, inducing white matter lesions and correlating with dementia. In vascular dementia, cholinergic reductions are correlated with cognitive impairment, and cholinesterase inhibitors have some benefit. Most lipid microemboli from cardiac surgery pass through the brain in a few days, but some remain for weeks. They can cause what appears to be a type of vascular dementia years after surgery. Donepezil has shown some benefit. Emboli, such as clots, cholesterol crystals, and microspheres can be extruded through the walls of cerebral vessels, but there is no evidence yet that lipid emboli undergo such extravasation. PMID:20946471

  16. Distribution of transvascular pathway sizes through the pulmonary microvascular barrier.

    PubMed

    McNamee, J E

    1987-01-01

    Mathematical models of solute and water exchange in the lung have been helpful in understanding factors governing the volume flow rate and composition of pulmonary lymph. As experimental data and models become more encompassing, parameter identification becomes more difficult. Pore sizes in these models should approach and eventually become equivalent to actual physiological pathway sizes as more complex and accurate models are tried. However, pore sizes and numbers vary from model to model as new pathway sizes are added. This apparent inconsistency of pore sizes can be explained if it is assumed that the pulmonary blood-lymph barrier is widely heteroporous, for example, being composed of a continuous distribution of pathway sizes. The sieving characteristics of the pulmonary barrier are reproduced by a log normal distribution of pathway sizes (log mean = -0.20, log s.d. = 1.05). A log normal distribution of pathways in the microvascular barrier is shown to follow from a rather general assumption about the nature of the pulmonary endothelial junction.

  17. Biomarker for early renal microvascular and diabetic kidney diseases.

    PubMed

    Futrakul, Narisa; Futrakul, Prasit

    2017-11-01

    Recognition of early stage of diabetic kidney disease, under common practice using biomarkers, namely microalbuminuria, serum creatinine level above 1 mg/dL and accepted definition of diabetic kidney disease associated with creatinine clearance value below 60 mL/min/1.73 m 2 , is unlikely. This would lead to delay treatment associated with therapeutic resistance to vasodilator due to a defective vascular homoeostasis. Other alternative biomarkers related to the state of microalbuminuria is not sensitive to screen for early diabetic kidney disease (stages I, II). In this regard, a better diagnostic markers to serve for this purpose are creatinine clearance, fractional excretion of magnesium (FE Mg), cystatin C. Recently, renal microvascular disease and renal ischemia have been demonstrated to correlate indirectly with the development of diabetic kidney disease and its function. Among these are angiogenic and anti-angiogenic factors, namely VEGF, VEGF receptors, angiopoietins and endostatin. With respect to therapeutic prevention, implementation of treatment at early stage of diabetic and nondiabetic kidney disease is able to restore renal perfusion and function.

  18. Cardiac microvascular endothelial cells express a functional Ca+ -sensing receptor.

    PubMed

    Berra Romani, Roberto; Raqeeb, Abdul; Laforenza, Umberto; Scaffino, Manuela Federica; Moccia, Francesco; Avelino-Cruz, Josè Everardo; Oldani, Amanda; Coltrini, Daniela; Milesi, Veronica; Taglietti, Vanni; Tanzi, Franco

    2009-01-01

    The mechanism whereby extracellular Ca(2+) exerts the endothelium-dependent control of vascular tone is still unclear. In this study, we assessed whether cardiac microvascular endothelial cells (CMEC) express a functional extracellular Ca(2+)-sensing receptor (CaSR) using a variety of techniques. CaSR mRNA was detected using RT-PCR, and CaSR protein was identified by immunocytochemical analysis. In order to assess the functionality of the receptor, CMEC were loaded with the Ca(2+)-sensitive fluorochrome, Fura-2/AM. A number of CaSR agonists, such as spermine, Gd(3+), La(3+) and neomycin, elicited a heterogeneous intracellular Ca(2+) signal, which was abolished by disruption of inositol 1,4,5-trisphosphate (InsP(3)) signaling and by depletion of intracellular stores with cyclopiazonic acid. The inhibition of the Na(+)/Ca(2+) exchanger upon substitution of extracellular Na(+) unmasked the Ca(2+) signal triggered by an increase in extracellular Ca(2+) levels. Finally, aromatic amino acids, which function as allosteric activators of CaSR, potentiated the Ca(2+) response to the CaSR agonist La(3+). These data provide evidence that CMEC express CaSR, which is able to respond to physiological agonists by mobilizing Ca(2+) from intracellular InsP(3)-sensitive stores. Copyright 2008 S. Karger AG, Basel.

  19. MR contrast media for myocardial viability, microvascular integrity and perfusion.

    PubMed

    Saeed, M; Wendland, M F; Watzinger, N; Akbari, H; Higgins, C B

    2000-06-01

    Cardiovascular imaging requires an appreciation of rapidly evolving MR imaging sequences as well as careful utilization of intravascular, extracellular and intracellular MR contrast media. At the present time, clinical studies are restricted to the use of extracellular MR contrast media. MR imaging has the potential to noninvasively measure multiple parameters of the cardiovascular system in a single imaging session. Recent advances in fast and ultrafast MR imaging have considerably enhanced the capability of this technique, beyond the assessment of left ventricular wall motion and morphology into visualization of the coronary arteries and measurement of blood flow. During the course of the last several years, multiple strategies for imaging viable myocardium have been developed and validated using MR contrast media. Contrast enhanced dynamic MR imaging provides information regarding microvascular integrity and perfusion. Because these information can be provided noninvasively by MR imaging, repeated measurements can be performed in longitudinal studies to monitor the progression or regression of myocardial injury. Similar studies are needed to examine the effects of newly developed cardioprotective therapeutics. Development of suitable intravascular MR contrast medium may be essential for visualization of the coronary arteries and interventional therapies. MR imaging may emerge as one-stop-shop for evaluating the heart and coronary system. This capability will make MR imaging cost-effective in the first decade of this millennium.

  20. The photosensitizer talaporfinum caused microvascular embolization for photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Li, Liming; Aizawa, Katsuo

    2005-07-01

    Photodynamic therapy (PDT) has been evolving rapidly in the recent years. A second-generation Photosensitizer mono-1-aspartyl chlorine 6 (Talaporfin / Npe6 / ME2906, Japan Meiji Seika, Ltd.) has been sanctified for the lung cancer clinical PDT by the Japan Ministry of Health, Labor and Welfare. In this paper, Talaporfin was injected to the implant cancer of a mouse a Talaporfin dose of 5mg/kg through intravenous. After 6 hours, the fluorescence images of the mouse were observed with a microscope and a 664 nm diode laser. Effects of therapy were clarified using the different irradiation energies of the laser (50, 100, 200 J/cm2). Both in plasma and in cancer, the concentrations of Talaporfin were analyzed using High Performance Liquid Chromatography (HPLC). Authors find that the higher concentrations of Talaporfin in plasma, the better PDD effect. It is experimentally verified that local microvascular embolisms in the cancer are formed for photodynamic therapy after the Talaporfin injection and the laser irradiation.

  1. Comparison of tissue processing methods for microvascular visualization in axolotls.

    PubMed

    Montoro, Rodrigo; Dickie, Renee

    2017-01-01

    The vascular system, the pipeline for oxygen and nutrient delivery to tissues, is essential for vertebrate development, growth, injury repair, and regeneration. With their capacity to regenerate entire appendages throughout their lifespan, axolotls are an unparalleled model for vertebrate regeneration, but they lack many of the molecular tools that facilitate vascular imaging in other animal models. The determination of vascular metrics requires high quality image data for the discrimination of vessels from background tissue. Quantification of the vasculature using perfused, cleared specimens is well-established in mammalian systems, but has not been widely employed in amphibians. The objective of this study was to optimize tissue preparation methods for the visualization of the microvascular network in axolotls, providing a basis for the quantification of regenerative angiogenesis. To accomplish this aim, we performed intracardiac perfusion of pigment-based contrast agents and evaluated aqueous and non-aqueous clearing techniques. The methods were verified by comparing the quality of the vascular images and the observable vascular density across treatment groups. Simple and inexpensive, these tissue processing techniques will be of use in studies assessing vascular growth and remodeling within the context of regeneration. Advantages of this method include: •Higher contrast of the vasculature within the 3D context of the surrounding tissue •Enhanced detection of microvasculature facilitating vascular quantification •Compatibility with other labeling techniques.

  2. Cardiac microvascular rarefaction in hyperthyroidism-induced left ventricle dysfunction.

    PubMed

    Freitas, Felipe; Estato, Vanessa; Carvalho, Vinícius Frias; Torres, Rafael Carvalho; Lessa, Marcos Adriano; Tibiriçá, Eduardo

    2013-10-01

    The pathophysiology underlying hyperthyroidism-induced left ventricle (LV) dysfunction and hypertrophy directly involves the heart and indirectly involves the neuroendocrine systems. The effects of hyperthyroidism on the microcirculation are still controversial in experimental models. We investigated the effects of hyperthyroidism on the cardiac function and microcirculation of an experimental rat model. Male Wistar rats (170-250 g) were divided into two groups: the euthyroid group (n = 10), which was treated with 0.9% saline solution, and the hyperthyroid group (n = 10), which was treated with l-thyroxine (600 μg/kg/day, i.p.) during 14 days. An echocardiographic study was performed to evaluate the alterations in cardiac function, structure and geometry. The structural capillary density and the expression of angiotensin II AT1 receptor in the LV were analyzed using histochemistry and immunohistochemistry, respectively. Hyperthyroidism was found to induce profound cardiovascular alterations, such as systolic hypertension, tachycardia, LV dysfunction, cardiac hypertrophy, and myocardial fibrosis. This study demonstrates the existence of structural capillary rarefaction and the down-regulation of the cardiac angiotensin II AT1 receptor in the myocardium of hyperthyroid rats in comparison with euthyroid rats. Microvascular rarefaction may be involved in the pathophysiology of hyperthyroidism-induced cardiovascular alterations. © 2013 John Wiley & Sons Ltd.

  3. [Improving Primary Culture of Pulmonary Microvascular Endothelial Cells of Rats].

    PubMed

    Jiang, Ling; Hu, Yuan-Dong; Xu, Fei-Fei; Wang, Ting-Hua

    2016-09-01

    To improve the culturing method of pulmonary microvascular endothelial cells (PMEVCs) of SD rats. The culturing processes in regard to obtaining peripheral lung tissue, attaching tissue block,preparing medium and subculturing were modified.These included an injection of heparin sodium before anesthesia, abdominal bleeding, opening of chest when breathing stopped, improvement of operational details, reduction of pollution by adding penicillin and streptomycin, discard of tissues after 48 h of primary culturing, remove of fibroblasts by a second digestion, and identification of cells using a fluorescence microscope for binding with lectin from BSI (FITC-BSI).An inverted microscope was used to observe the morphological characteristics of PMEVCs. Purified PMEVCs were obtained,which displayed a polygon or short fusiform, exhibiting a typical cobblestone-like morphology. The morphology of PMVECs turned into swirling or long fusiform following subculture or changes in culture conditions. The results of FITC-BSI assay showed that more than 90% cells were stained with green fluorescence. Purified PMEVCs with a good growth state and subculture stability can be obtained using the modified method.

  4. Neurogenic airway microvascular leakage induced by toluene inhalation in rats.

    PubMed

    Sakamoto, Tatsuo; Kamijima, Michihiro; Miyake, Mio

    2012-06-15

    Toluene is a representative airborne occupational and domestic pollutant that causes eye and respiratory tract irritation. We investigated whether a single inhalation of toluene elicits microvascular leakage in the rat airway. We also evaluated the effects of CP-99,994, a tachykinin NK(1) receptor antagonist, and ketotifen, a histamine H1 receptor antagonist with mast cell-stabilizing properties, on the airway response. The content of Evans blue dye that extravasated into the tissues was measured as an index of plasma leakage. Toluene (18-450 ppm, 10 min) concentration-dependently induced dye leakage into the trachea and main bronchi of anesthetized and mechanically ventilated rats. Toluene at concentrations of ≥ 50 and ≥ 30 ppm caused significant responses in the trachea and main bronchi, respectively, which both peaked after exposure to 135 ppm toluene for 10 min. This response was abolished by CP-99,994 (5 mg/kg i.v.), but not by ketotifen (1mg/kg i.v.). Nebulized phosphoramidon (1 mM, 1 min), a neutral endopeptidase 24.11 inhibitor, significantly enhanced the response induced by toluene (135 ppm, 10 min) compared with nebulized 0.9% saline (1 min). These results show that toluene can rapidly increase airway plasma leakage that is predominantly mediated by tachykinins endogenously released from airway sensory nerves. However, mast cell activation might not be important in this airway response. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Preoperative assessment of microvascular invasion in hepatocellular carcinoma

    NASA Astrophysics Data System (ADS)

    Chakraborty, Jayasree; Zheng, Jian; Gönen, Mithat; Jarnagin, William R.; DeMatteo, Ronald P.; Do, Richard K. G.; Simpson, Amber L.

    2017-03-01

    Hepatocellular carcinoma (HCC) is the most common liver cancer and the third leading cause of cancer-related death worldwide.1 Resection or liver transplantation may be curative in patients with early-stage HCC but early recurrence is common.2, 3 Microvascular invasion (MVI) is one of the most important predictors of early recurrence.3 The identification of MVI prior to surgery would optimally select patients for potentially curative resection or liver transplant. However, MVI can only be diagnosed by microscopic assessment of the resected tumor. The aim of the present study is to apply CT-based texture analysis to identify pre-operative imaging predictors of MVI in patients with HCC. Texture features are derived from CT and analyzed individually as well as in combination, to evaluate their ability to predict MVI. A two-stage classification is employed: HCC tumors are automatically categorized into uniform or heterogenous groups followed by classification into the presence or absence of MVI. We achieve an area under the receiver operating characteristic curve (AUC) of 0.76 and accuracy of 76.7% for uniform lesions and AUC of 0.79 and accuracy of 74.06% for heterogeneous tumors. These results suggest that MVI can be accurately and objectively predicted from preoperative CT scans.

  6. Comparison of clinical outcomes between laminoplasty, posterior decompression with instrumented fusion, and anterior decompression with fusion for K-line (-) cervical ossification of the posterior longitudinal ligament.

    PubMed

    Koda, Masao; Mochizuki, Makondo; Konishi, Hiroaki; Aiba, Atsuomi; Kadota, Ryo; Inada, Taigo; Kamiya, Koshiro; Ota, Mitsutoshi; Maki, Satoshi; Takahashi, Kazuhisa; Yamazaki, Masashi; Mannoji, Chikato; Furuya, Takeo

    2016-07-01

    The K-line, which is a virtual line that connects the midpoints of the anteroposterior diameter of the spinal canal at C2 and C7 in a plain lateral radiogram, is a useful preoperative predictive indicator for sufficient decompression by laminoplasty (LMP) for ossification of the posterior longitudinal ligament (OPLL). K-line is defined as (+) when the peak of OPLL does not exceed the K-line, and is defined as (-) when the peak of OPLL exceeds the K-line. For patients with K-line (-) OPLL, LMP often results in poor outcome. The aim of the present study was to compare the clinical outcome of LMP, posterior decompression with instrumented fusion (PDF) and anterior decompression and fusion (ADF) for patients with K-line (-) OPLL. The present study included patients who underwent surgical treatment including LMP, PDF and ADF for K-line (-) cervical OPLL. We retrospectively compared the clinical outcome of those patients in terms of Japanese Orthopedic Association score (JOA score) recovery rate. JOA score recovery rate was significantly higher in the ADF group compared with that in the LMP group and the PDF group. The JOA score recovery rate in the PDF group was significantly higher than that in the LMP group. LMP should not be used for K-line (-) cervical OPLL. ADF is one of the suitable surgical treatments for K-line (-) OPLL. Both ADF and PDF are applicable for K-line (-) OPLL according to indications set by each institute and surgical decisions.

  7. Transfer of Learning from Practicing Microvascular Anastomosis on Silastic Tubes to Rat Abdominal Aorta.

    PubMed

    Mokhtari, Pooneh; Tayebi Meybodi, Ali; Lawton, Michael T; Payman, Andre; Benet, Arnau

    2017-12-01

    Learning to perform microvascular anastomosis is difficult. Laboratory practice models using artificial vessels are frequently used for this purpose. However, the efficacy of such practice models has not been objectively assessed for the performance of microvascular anastomosis during live surgical settings. This study was conducted to assess the transfer of learning from practicing microvascular anastomosis on tubes to anastomosing rat abdominal aorta. Ten surgeons without any experience in microvascular anastomosis were randomly assigned to an experimental or a control group. Both groups received didactic and visual training on end-to-end microvascular anastomosis. The experimental group received 24 sessions of hands-on training on microanastomosis using Silastic tubes. Next, both groups underwent recall tests on weeks 1, 2, and 8 after training. The recall test consisted of completing an end-to-end anastomosis on the rat's abdominal aorta. Anastomosis score, the time to complete the anastomosis, and the average time to place 1 stitch on the vessel perimeter were compared between the 2 groups. Compared with the control group, the experimental group did significantly better in terms of anastomosis score, total time, and per-stitch time. The measured variables showed stability and did not change significantly between the 3 recall tests. The skill of microvascular anastomosis is transferred from practicing on Silastic tubes to rat's abdominal aorta. Considering the relative advantages of Silastic tubes to live rodent surgeries, such as lower cost and absence of ethical issues, our results support the widespread use of Silastic tubes in training programs for microvascular anastomosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Microvascular versus macrovascular cerebral vasomotor reactivity in patients with severe internal carotid artery stenosis or occlusion.

    PubMed

    Zirak, Peyman; Delgado-Mederos, Raquel; Dinia, Lavinia; Martí-Fàbregas, Joan; Durduran, Turgut

    2014-02-01

    In patients with severe internal carotid artery steno-occlusive lesions (ISOL), impaired cerebrovascular reactivity (CVR) is predictive of future ischemic stroke (IS) or transient ischemic attack (TIA). Therefore, the evaluation of CVR in ISOL patients may be a means to evaluate the risk for IS/TIA and decide on an intervention. Our aim was (1) to explore the feasibility of concurrent near-infrared spectroscopy (NIRS-DOS), diffuse correlation spectroscopy, and transcranial Doppler for CVR assessment in ISOL patients, and (2) to compare macrovascular and microvascular CVR in ISOL patients and explore its potential for IS/TIA risk stratification. Twenty-seven ISOL patients were recruited. The changes in continuous microvascular and macrovascular hemodynamics upon acetazolamide injection were used to determine CVR. Oxyhemoglobin (HbO2, by near-infrared spectroscopy), microvascular cerebral blood flow (CBF, by diffuse correlation spectroscopy) and CBF velocity (by transcranial Doppler) showed significant increases upon acetazolamide injection in all subjects (P < .03). Only macrovascular CVR (P = .024) and none of the microvascular measures were significantly dependent on the presence of ISOL. In addition, while CBF was significantly correlated with HbO2, neither of these microvascular measures correlated with macrovascular CBF velocity. We demonstrated the simultaneous, continuous, and noninvasive evaluation of CVR at both the microvasculature and macrovasculature. We found that macrovascular CVR response depends on the presence of ISOL, whereas the microvascular CVR did not significantly depend on the ISOL presence, possibly due to the role of collaterals other than those of the circle of Willis. The concurrent microvascular and macrovascular CVR measurement in the ISOL patients might improve future IS/TIA risk assessment. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

  9. Microvascular and Macrovascular Abnormalities and Cognitive and Physical Function in Older Adults: Cardiovascular Health Study.

    PubMed

    Kim, Dae Hyun; Grodstein, Francine; Newman, Anne B; Chaves, Paulo H M; Odden, Michelle C; Klein, Ronald; Sarnak, Mark J; Lipsitz, Lewis A

    2015-09-01

    To evaluate and compare the associations between microvascular and macrovascular abnormalities and cognitive and physical function Cross-sectional analysis of the Cardiovascular Health Study (1998-1999). Community. Individuals with available data on three or more of five microvascular abnormalities (brain, retina, kidney) and three or more of six macrovascular abnormalities (brain, carotid artery, heart, peripheral artery) (N = 2,452; mean age 79.5). Standardized composite scores derived from three cognitive tests (Modified Mini-Mental State Examination, Digit-Symbol Substitution Test, Trail-Making Test (TMT)) and three physical tests (gait speed, grip strength, 5-time sit to stand) Participants with high microvascular and macrovascular burden had worse cognitive (mean score difference = -0.30, 95% confidence interval (CI) = -0.37 to -0.24) and physical (mean score difference = -0.32, 95% CI = -0.38 to -0.26) function than those with low microvascular and macrovascular burden. Individuals with high microvascular burden alone had similarly lower scores than those with high macrovascular burden alone (cognitive function: -0.16, 95% CI = -0.24 to -0.08 vs -0.13, 95% CI = -0.20 to -0.06; physical function: -0.15, 95% CI = -0.22 to -0.08 vs -0.12, 95% CI = -0.18 to -0.06). Psychomotor speed and working memory, assessed using the TMT, were only impaired in the presence of high microvascular burden. Of the 11 vascular abnormalities considered, white matter hyperintensity, cystatin C-based glomerular filtration rate, large brain infarct, and ankle-arm index were independently associated with cognitive and physical function. Microvascular and macrovascular abnormalities assessed using noninvasive tests of the brain, kidney, and peripheral artery were independently associated with poor cognitive and physical function in older adults. Future research should evaluate the usefulness of these tests in prognostication. © 2015, Copyright the Authors Journal compilation © 2015

  10. Early microvascular changes in the preterm neonate: a comparative study of the human and guinea pig.

    PubMed

    Dyson, Rebecca M; Palliser, Hannah K; Lakkundi, Anil; de Waal, Koert; Latter, Joanna L; Clifton, Vicki L; Wright, Ian M R

    2014-09-17

    Dysfunction of the transition from fetal to neonatal circulatory systems may be a major contributor to poor outcome following preterm birth. Evidence exists in the human for both a period of low flow between 5 and 11 h and a later period of increased flow, suggesting a hypoperfusion-reperfusion cycle over the first 24 h following birth. Little is known about the regulation of peripheral blood flow during this time. The aim of this study was to conduct a comparative study between the human and guinea pig to characterize peripheral microvascular behavior during circulatory transition. Very preterm (≤28 weeks GA), preterm (29-36 weeks GA), and term (≥37 weeks GA) human neonates underwent laser Doppler analysis of skin microvascular blood flow at 6 and 24 h from birth. Guinea pig neonates were delivered prematurely (62 day GA) or at term (68-71 day GA) and laser Doppler analysis of skin microvascular blood flow was assessed every 2 h from birth. In human preterm neonates, there is a period of high microvascular flow at 24 h after birth. No period of low flow was observed at 6 h. In preterm animals, microvascular flow increased after birth, reaching a peak at 10 h postnatal age. Blood flow then steadily decreased, returning to delivery levels by 24 h. Preterm birth was associated with higher baseline microvascular flow throughout the study period in both human and guinea pig neonates. The findings do not support a hypoperfusion-reperfusion cycle in the microcirculation during circulatory transition. The guinea pig model of preterm birth will allow further investigation of the mechanisms underlying microvascular function and dysfunction during the initial extrauterine period. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  11. Probabilistic Assessment of Hypobaric Decompression Sickness Treatment Success

    NASA Technical Reports Server (NTRS)

    Conkin, Johnny; Abercromby, Andrew F. J.; Dervay, Joseph P.; Feiveson, Alan H.; Gernhardt, Michael L.; Norcross, Jason R.; Ploutz-Snyder, Robert; Wessel, James H., III

    2014-01-01

    The Hypobaric Decompression Sickness (DCS) Treatment Model links a decrease in computed bubble volume from increased pressure (DeltaP), increased oxygen (O2) partial pressure, and passage of time during treatment to the probability of symptom resolution [P(symptom resolution)]. The decrease in offending volume is realized in 2 stages: a) during compression via Boyle's Law and b) during subsequent dissolution of the gas phase via the O2 window. We established an empirical model for the P(symptom resolution) while accounting for multiple symptoms within subjects. The data consisted of 154 cases of hypobaric DCS symptoms along with ancillary information from tests on 56 men and 18 women. Our best estimated model is P(symptom resolution) = 1 / (1+exp(-(ln(Delta P) - 1.510 + 0.795×AMB - 0.00308×Ts) / 0.478)), where (DeltaP) is pressure difference (psid), AMB = 1 if ambulation took place during part of the altitude exposure, otherwise AMB = 0; and where Ts is the elapsed time in mins from start of the altitude exposure to recognition of a DCS symptom. To apply this model in future scenarios, values of DeltaP as inputs to the model would be calculated from the Tissue Bubble Dynamics Model based on the effective treatment pressure: (DeltaP) = P2 - P1 | = P1×V1/V2 - P1, where V1 is the computed volume of a spherical bubble in a unit volume of tissue at low pressure P1 and V2 is computed volume after a change to a higher pressure P2. If 100% ground level O2 (GLO) was breathed in place of air, then V2 continues to decrease through time at P2 at a faster rate. This calculated value of (DeltaP then represents the effective treatment pressure at any point in time. Simulation of a "pain-only" symptom at 203 min into an ambulatory extravehicular activity (EVA) at 4.3 psia on Mars resulted in a P(symptom resolution) of 0.49 (0.36 to 0.62 95% confidence intervals) on immediate return to 8.2 psia in the Multi-Mission Space Exploration Vehicle. The P(symptom resolution) increased

  12. Analysis of direct costs of decompressive craniectomy in victims of traumatic brain injury.

    PubMed

    Badke, Guilherme Lellis; Araujo, João Luiz Vitorino; Miura, Flávio Key; Guirado, Vinicius Monteiro de Paula; Saade, Nelson; Paiva, Aline Lariessy Campos; Avelar, Tiago Marques; Pedrozo, Charles Alfred Grander; Veiga, José Carlos Esteves

    2018-04-01

    Decompressive craniectomy is a procedure required in some cases of traumatic brain injury (TBI). This manuscript evaluates the direct costs and outcomes of decompressive craniectomy for TBI in a developing country and describes the epidemiological profile. A retrospective study was performed using a five-year neurosurgical database, taking a sample of patients with TBI who underwent decompressive craniectomy. Several variables were considered and a formula was developed for calculating the total cost. Most patients had multiple brain lesions and the majority (69.0%) developed an infectious complication. The general mortality index was 68.8%. The total cost was R$ 2,116,960.22 (US$ 661,550.06) and the mean patient cost was R$ 66,155.00 (US$ 20,673.44). Decompressive craniectomy for TBI is an expensive procedure that is also associated with high morbidity and mortality. This was the first study performed in a developing country that aimed to evaluate the direct costs. Prevention measures should be a priority.

  13. Assessment of two methods of gastric decompression for the initial management of gastric dilatation-volvulus.

    PubMed

    Goodrich, Z J; Powell, L L; Hulting, K J

    2013-02-01

    To assess gastric trocarization and orogastric tubing as a means of gastric decompression for the initial management of gastric dilatation-volvulus. Retrospective review of 116 gastric dilatation-volvulus cases from June 2001 to October 2009. Decompression was performed via orogastric tubing in 31 dogs, gastric trocarization in 39 dogs and a combination of both in 46 dogs. Tubing was successful in 59 (75·5%) dogs and unsuccessful in 18 (23·4%) dogs. Trocarization was successful in 73 (86%) dogs and unsuccessful in 12 (14%) dogs. No evidence of gastric perforation was noted at surgery in dogs undergoing either technique. One dog that underwent trocarization had a splenic laceration identified at surgery that did not require treatment. Oesophageal rupture or aspiration pneumonia was not identified in any dog during hospitalization. No statistical difference was found between the method of gastric decompression and gastric compromise requiring surgical intervention or survival to discharge. Orogastric tubing and gastric trocarization are associated with low complication and high success rates. Either technique is an acceptable method for gastric decompression in dogs with gastric dilatation-volvulus. © 2013 British Small Animal Veterinary Association.

  14. Editorial Commentary: Subacromial Decompression Is Unnecessary in Most Routine Rotator Cuff Repairs.

    PubMed

    Solomon, Daniel J

    2017-07-01

    There is no need to perform subacromial decompression in partial bursal-sided rotator cuff repairs to obtain a good result. This, paired with the findings of previous studies of full-thickness rotator cuff repairs, suggests that extrinsic factors rarely affect the rotator cuff. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  15. Women's experiences of daily life after anterior cervical decompression and fusion surgery: A qualitative interview study.

    PubMed

    Hermansen, Anna; Peolsson, Anneli; Kammerlind, Ann-Sofi; Hjelm, Katarina

    2016-04-01

    To explore and describe women's experiences of daily life after anterior cervical decompression and fusion surgery. Qualitative explorative design. Fourteen women aged 39-62 years (median 52 years) were included 1.5-3 years after anterior cervical decompression and fusion for cervical disc disease. Individual semi-structured interviews were analysed by qualitative content analysis with an inductive approach. The women described their experiences of daily life in 5 different ways: being recovered to various extents; impact of remaining symptoms on thoughts and feelings; making daily life work; receiving support from social and occupational networks; and physical and behavioural changes due to interventions and encounters with healthcare professionals. This interview study provides insight into women's daily life after anterior cervical decompression and fusion. Whilst the subjects improved after surgery, they also experienced remaining symptoms and limitations in daily life. A variety of mostly active coping strategies were used to manage daily life. Social support from family, friends, occupational networks and healthcare professionals positively influenced daily life. These findings provide knowledge about aspects of daily life that should be considered in individualized postoperative care and rehabilitation in an attempt to provide better outcomes in women after anterior cervical decompression and fusion.

  16. Greater occipital nerve neuralgia caused by pathological arterial contact: treatment by surgical decompression.

    PubMed

    Cornely, Christiane; Fischer, Marius; Ingianni, Giulio; Isenmann, Stefan

    2011-04-01

    Occipital nerve neuralgia is a rare cause of severe headache, and may be difficult to treat. We report the case of a patient with occipital nerve neuralgia caused by pathological contact of the nerve with the occipital artery. The pain was refractory to medical treatment. Surgical decompression yielded complete remission. © 2010 American Headache Society.

  17. Application of COMPONT Medical Adhesive Glue for Tension-Reduced Duraplasty in Decompressive Craniotomy

    PubMed Central

    Zhou, Yujia; Wang, Gesheng; Liu, Jialin; Du, Yong; Wang, Lei; Wang, Xiaoyong

    2016-01-01

    Background The aim of this study was to evaluate the application of medical adhesive glue for tension-reduced duraplasty in decompressive craniotomy. Material/Methods A total of 56 cases were enrolled for this study from Jan 2013 to May 2015. All patients underwent decompressive craniotomy and the dura was repaired in all of them with tension-reduced duraplasty using the COMPONT medical adhesive to glue artificial dura together. The postoperative complications and the healing of dura mater were observed and recorded. Results No wound infection, epidural or subdural hematoma, cerebrospinal fluid leakage, or other complications associated with the procedure occurred, and there were no allergic reactions to the COMPONT medical adhesive glue. The second-phase surgery of cranioplasty was performed at 3 to 6 months after the decompressive craniotomy in 32 out of the 56 cases. During the cranioplasty we observed no adherence of the artificial dura mater patch to the skin flap, no residual COMPONT glue, or hydropic or contracture change of tissue at the surgical sites. Additionally, no defect or weakening of the adherence between the artificial dura mater patch and the self dura matter occurred. Conclusions COMPONT medical adhesive glue is a safe and reliable tool for tension-reduced duraplasty in decompressive craniotomy. PMID:27752035

  18. Impact of timing of cranioplasty on hydrocephalus after decompressive hemicraniectomy in malignant middle cerebral artery infarction.

    PubMed

    Finger, Tobias; Prinz, Vincent; Schreck, Evelyn; Pinczolits, Alexandra; Bayerl, Simon; Liman, Thomas; Woitzik, Johannes; Vajkoczy, Peter

    2017-02-01

    Patients with malignant middle cerebral artery infarction frequently develop hydrocephalus after decompressive hemicraniectomy. Hydrocephalus itself and known shunt related complications after ventriculo-peritoneal shunt implantation may negatively impact patientś outcome. Here, we aimed to identify factors associated with the development of hydrocephalus after decompressive hemicraniectomy in malignant middle cerebral artery infarction. A total of 99 consecutive patients with the diagnosis of large hemispheric infarctions and the indication for decompressive hemicraniectomy were included. We retrospectively evaluated patient characteristics (gender, age and selected preoperative risk factors), stroke characteristics (side, stroke volume and existing mass effect) and surgical characteristics (size of the bone flap, initial complication rate, time to cranioplasty, complication rate following cranioplasty, type of implant, number of revision surgeries and mortality). Frequency of hydrocephalus development was 10% in our cohort. Patients who developed a hydrocephalus had an earlier time point of bone flap reimplantation compared to the control group (no hydrocephalus=164±104days, hydrocephalus=108±52days, p<0.05). Additionally, numbers of revision surgeries after cranioplasty was associated with hydrocephalus with a trend towards significance (p=0.08). Communicating hydrocephalus is frequent in patients with malignant middle cerebral artery infarction after decompressive hemicraniectomy. A later time point of cranioplasty might lead to a lower incidence of required shunting procedures in general as we could show in our patient cohort. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Intravenous Perfluorocarbon After Onset of Decompression Sickness Decreases Mortality in 20-kg Swine

    DTIC Science & Technology

    2010-06-01

    administration of 0.1-1.5 ml· 10 kg- • Euthasol. After confirmation of death, the heart was exposed via thoracotomy and a large-bore cannula p laced in the...from undersea diving. Neural Clin 1992; 10:1031-45. 18. Hallenbeck JM, Bove AA, Elliott DH. Mechanisms underlying spinal cord damage in decompression

  20. Influence of Lumbar Lordosis on the Outcome of Decompression Surgery for Lumbar Canal Stenosis.

    PubMed

    Chang, Han Soo

    2018-01-01

    Although sagittal spinal balance plays an important role in spinal deformity surgery, its role in decompression surgery for lumbar canal stenosis is not well understood. To investigate the hypothesis that sagittal spinal balance also plays a role in decompression surgery for lumbar canal stenosis, a prospective cohort study analyzing the correlation between preoperative lumbar lordosis and outcome was performed. A cohort of 85 consecutive patients who underwent decompression for lumbar canal stenosis during the period 2007-2011 was analyzed. Standing lumbar x-rays and 36-item short form health survey questionnaires were obtained before and up to 2 years after surgery. Correlations between lumbar lordosis and 2 parameters of the 36-item short form health survey (average physical score and bodily pain score) were statistically analyzed using linear mixed effects models. There was a significant correlation between preoperative lumbar lordosis and the 2 outcome parameters at postoperative, 6-month, 1-year, and 2-year time points. A 10° increase of lumbar lordosis was associated with a 5-point improvement in average physical scores. This correlation was not present in preoperative scores. This study showed that preoperative lumbar lordosis significantly influences the outcome of decompression surgery on lumbar canal stenosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Use of computed tomography to assess volume change after endoscopic orbital decompression for Graves' ophthalmopathy.

    PubMed

    Schiff, Bradley A; McMullen, Caitlin P; Farinhas, Joaquim; Jackman, Alexis H; Hagiwara, Mari; McKellop, Jason; Lui, Yvonne W

    2015-01-01

    Orbital decompression is frequently performed in the management of patients with sight-threatening and disfiguring Graves' ophthalmopathy. The quantitative measurements of the change in orbital volume after orbital decompression procedures are not definitively known. Furthermore, the quantitative effect of septal deviation on volume change has not been previously analyzed. To provide quantitative measurement of orbital volume change after medial and inferior endoscopic decompression and describe a straightforward method of measuring this change using open-source technologies. A secondary objective was to assess the effect of septal deviation on orbital volume change. A retrospective review was performed on all patients undergoing medial and inferior endoscopic orbital decompression for Graves' ophthalmopathy at a tertiary care academic medical center. Pre-operative and post-operative orbital volumes were calculated from computed tomography (CT) data using a semi-automated segmenting technique and Osirix™, an open-source DICOM reader. Data were collected for pre-operative and post-operative orbital volumes, degree of septal deviation, time to follow-up scan, and individual patient Hertel scores. Nine patients (12 orbits) were imaged before and after decompression. Mean pre-operative orbital volume was 26.99 cm(3) (SD=2.86 cm(3)). Mean post-operative volume was 33.07 cm(3) (SD=3.96 cm(3)). The mean change in volume was 6.08 cm(3) (SD=2.31 cm(3)). The mean change in Hertel score was 4.83 (SD=0.75). Regression analysis of change in volume versus follow-up time to imaging indicates that follow-up time to imaging has little effect on change in volume (R=-0.2), and overall mean maximal septal deviation toward the operative side was -0.5mm. Negative values were attributed to deviation away form the operative site. A significant correlation was demonstrated between change in orbital volume and septal deviation distance site (R=0.66), as well as between change in orbital

  2. Effect of Subspine Decompression on Rectus Femoris Integrity and Iliopsoas Excursion: A Cadaveric Study.

    PubMed

    El-Shaar, Rami; Stanton, Michael; Biehl, Scott; Giordano, Brian

    2015-10-01

    To determine the relative influence of anteroinferior iliac spine (AIIS) or subspine decompression on proximal rectus femoris integrity and iliopsoas excursion throughout a physiological range of motion. Nineteen cadaveric hips from 10 specimens were dissected to retain the origin of the rectus femoris direct and indirect heads. The anatomic footprints of the origins were measured with calipers. Serial 5-mm resections of the AIIS were made to determine the extent of proximal tendon disruption that corresponded to each resection. Iliopsoas tendon tracking was also assessed after sequential AIIS decompression by measuring the excursion of the medial border of the iliopsoas tendon as it traveled from its native resting position to the point where it first encountered bony impingement at the AIIS. The mean proximal-distal footprint of the rectus femoris direct head was 17.95 ± 2.99 mm. The mean medial-lateral distance was 11.84 ± 2.34 mm. There was a consistent bare area along the inferior aspect of the AIIS that averaged 4.84 ± 1.42 mm. The average percentage of remaining footprint after each 5-mm resection (5 to 25 mm) was 96%, 65%, 35%, 14%, and 11%, respectively, with statistical significance noted after resections larger than 5 mm (P < .001). The native excursion distance of the iliopsoas tendon was 14.05 mm. With each 5-mm resection, the percentage of excursion before impingement on the AIIS increased by 18%, 45%, 72%, 95%, and 100%, respectively, which was statistically significance after all resections (P < .001). Our study maps the anatomic footprint of the direct head of the rectus femoris tendon and confirms a previously identified bare area along the inferior aspect of the AIIS. Female cadaveric hips had a significantly smaller rectus footprint than male cadavers in our study (P < .001). Subspine decompression greater than 10 mm significantly compromises the rectus femoris origin and should be avoided when performing arthroscopic AIIS decompression. In

  3. Economic evaluation of decompressive craniectomy versus barbiturate coma for refractory intracranial hypertension following traumatic brain injury.

    PubMed

    Alali, Aziz S; Naimark, David M J; Wilson, Jefferson R; Fowler, Robert A; Scales, Damon C; Golan, Eyal; Mainprize, Todd G; Ray, Joel G; Nathens, Avery B

    2014-10-01

    Decompressive craniectomy and barbiturate coma are often used as second-tier strategies when intracranial hypertension following severe traumatic brain injury is refractory to first-line treatments. Uncertainty surrounds the decision to choose either treatment option. We investigated which strategy is more economically attractive in this context. We performed a cost-utility analysis. A Markov Monte Carlo microsimulation model with a life-long time horizon was created to compare quality-adjusted survival and cost of the two treatment strategies, from the perspective of healthcare payer. Model parameters were estimated from the literature. Two-dimensional simulation was used to incorporate parameter uncertainty into the model. Value of information analysis was conducted to identify major drivers of decision uncertainty and focus future research. Trauma centers in the United States. Base case was a population of patients (mean age = 25 yr) who developed refractory intracranial hypertension following traumatic brain injury. We compared two treatment strategies: decompressive craniectomy and barbiturate coma. Decompressive craniectomy was associated with an average gain of 1.5 quality-adjusted life years relative to barbiturate coma, with an incremental cost-effectiveness ratio of $9,565/quality-adjusted life year gained. Decompressive craniectomy resulted in a greater quality-adjusted life expectancy 86% of the time and was more cost-effective than barbiturate coma in 78% of cases if our willingness-to-pay threshold is $50,000/quality-adjusted life year and 82% of cases at a threshold of $100,000/quality-adjusted life year. At older age, decompressive craniectomy continued to increase survival but at higher cost (incremental cost-effectiveness ratio = $197,906/quality-adjusted life year at mean age = 85 yr). Based on available evidence, decompressive craniectomy for the treatment of refractory intracranial hypertension following traumatic brain injury provides better

  4. Lid wiper microvascular responses as an indicator of contact lens discomfort

    PubMed Central

    Deng, Zhihong; Wang, Jianhua; Jiang, Hong; Fadli, Zohra; Liu, Che; Tan, Jia; Zhou, Jin

    2016-01-01

    Purpose To analyze quantitatively the alterations in the microvascular network of the upper tarsal conjunctiva, lid wiper, and bulbar conjunctiva relative to ocular discomfort after contact lens wear. Design A prospective, cross-over clinical study. Methods Functional slit-lamp biomicroscopy (FSLB) was used to image the microvascular network of the upper tarsal conjunctiva, lid wiper, and bulbar conjunctiva. The microvascular network was automatically segmented, and fractal analyses were performed to yield the fractal dimension (Dbox) that represented vessel density. Sixteen healthy subjects (nine female and seven male) with an average age of 35.5 ± 6.7 years old (mean ± standard deviation) were recruited. The right eye was imaged at 9 AM and 3 PM at the first visit (Day 1) when the subject was not wearing contact lenses. During the second visit (Day 2), the right eye was fit with a contact lens for 6 h. Microvascular imaging was performed before (at 9 AM) and after lens wear (at 3 PM). Ocular comfort was rated using a 50-point visual analogue scale before and after 6 h of lens wear, and its relationships with microvascular parameters were analyzed. Results There were no significant differences in Dbox among the upper tarsal conjunctiva, lid wiper, and bulbar conjunctiva among the measurements at 9 AM (Day 1 and Day 2) and 3 PM (Day 1) when the subjects were not wearing the lenses (P > 0.05), whereas after 6 h of lens wear, the microvascular network densities were increased in all three of these locations. Dbox of the lid wiper increased from 1.411 ± 0.116 to 1.548 ± 0.079 after 6 h of contact lens wear (P < 0.01). Dbox of the tarsal conjunctiva was 1.731 ± 0.026 at baseline and increased to 1.740 ± 0.030 (P < 0.05). Dbox of the bulbar conjunctiva increased from 1.587 ± 0.059 to 1.632 ± 0.060 (P < 0.001). The decrease in ocular discomfort was strongly related to the Dbox change in the lid wiper (r = 0.61, P < 0.05). There were no correlations between the

  5. Microvascular disorders in obese Zucker rats are restored by a rice bran diet.

    PubMed

    Justo, M L; Claro, C; Vila, E; Herrera, M D; Rodriguez-Rodriguez, R

    2014-05-01

    Nutritional-based approaches aimed to prevent microvascular dysfunction associated to obesity present potential advantages over pharmacological strategies. Our aim was to test whether a rice bran enzymatic extract (RBEE)-supplemented diet could attenuate microvascular alterations in obese rats. Lean and obese Zucker rats were fed standard diet supplemented or not with 1% and 5% RBEE for 20 weeks. Functional studies were performed in small mesenteric arteries in isometric myograph. Immunoblotting and fluorescence studies were made in arterial homogenates and arterial sections, respectively. RBEE-supplementation restored microvascular function in obese rats through a marked increase in NO and endothelial-derived hyperpolarizing factor contribution by up-regulation of eNOS and calcium-activated potassium channels expression, respectively, in association to a substantial reduction of microvascular inflammation and superoxide anion formation. These data agrees with the beneficial actions of RBEE on dyslipidemia, hyperinsulinemia and hypertension in obesity. The multi-factorial properties of RBEE-diet, especially for restoring the function of small resistance arteries shows this dietary-based approach to be a promising candidate for prevention of microvascular alterations in obesity, which are crucial in cardiovascular events in obese subjects. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. The effects of anti-obesity intervention with orlistat and sibutramine on microvascular endothelial function.

    PubMed

    Al-Tahami, Belqes Abdullah Mohammad; Ismail, Ab Aziz Al-Safi; Bee, Yvonne Tee Get; Awang, Siti Azima; Salha Wan Abdul Rani, Wan Rimei; Sanip, Zulkefli; Rasool, Aida Hanum Ghulam

    2015-01-01

    Obesity is associated with impaired microvascular endothelial function. We aimed to determine the effects of orlistat and sibutramine treatment on microvascular endothelial function, anthropometric and lipid profile, blood pressure (BP), and heart rate (HR). 76 subjects were recruited and randomized to receive orlistat 120 mg three times daily or sibutramine 10 mg daily for 9 months. Baseline weight, BMI, BP, HR and lipid profile were taken. Microvascular endothelial function was assessed using laser Doppler fluximetry and iontophoresis process. Maximum change (max), percent change (% change) and peak flux (peak) in perfusion to acetylcholine (ACh) and sodium nitroprusside (SNP) iontophoresis were used to quantify endothelium dependent and independent vasodilatations. 24 subjects in both groups completed the trial. After treatment, weight and BMI were decreased for both groups. AChmax, ACh % change and ACh peak were increased in orlistat-treated group but no difference was observed for sibutramine-treated group. BP and total cholesterol (TC) were reduced for orlistat-treated group. HR was reduced for orlistat-treated group but was increased in sibutramine-treated group. 9 months treatment with orlistat significantly improved microvascular endothelial function. This was associated with reductions in weight, BMI, BP, HR, TC and low density lipoprotein cholesterol. No effect was seen in microvascular endothelial function with sibutramine.

  7. A nanobiosensor for dynamic single cell analysis during microvascular self-organization.

    PubMed

    Wang, S; Sun, J; Zhang, D D; Wong, P K

    2016-10-14

    The formation of microvascular networks plays essential roles in regenerative medicine and tissue engineering. Nevertheless, the self-organization mechanisms underlying the dynamic morphogenic process are poorly understood due to a paucity of effective tools for mapping the spatiotemporal dynamics of single cell behaviors. By establishing a single cell nanobiosensor along with live cell imaging, we perform dynamic single cell analysis of the morphology, displacement, and gene expression during microvascular self-organization. Dynamic single cell analysis reveals that endothelial cells self-organize into subpopulations with specialized phenotypes to form microvascular networks and identifies the involvement of Notch1-Dll4 signaling in regulating the cell subpopulations. The cell phenotype correlates with the initial Dll4 mRNA expression level and each subpopulation displays a unique dynamic Dll4 mRNA expression profile. Pharmacological perturbations and RNA interference of Notch1-Dll4 signaling modulate the cell subpopulations and modify the morphology of the microvascular network. Taken together, a nanobiosensor enables a dynamic single cell analysis approach underscoring the importance of Notch1-Dll4 signaling in microvascular self-organization.

  8. Selective Activation of Sphingosine 1-Phosphate Receptors 1 and 3 Promotes Local Microvascular Network Growth

    PubMed Central

    Sefcik, Lauren S.; Petrie Aronin, Caren E.; Awojoodu, Anthony O.; Shin, Soo J.; Mac Gabhann, Feilim; MacDonald, Timothy L.; Wamhoff, Brian R.; Lynch, Kevin R.; Peirce, Shayn M.

    2011-01-01

    Proper spatial and temporal regulation of microvascular remodeling is critical to the formation of functional vascular networks, spanning the various arterial, venous, capillary, and collateral vessel systems. Recently, our group has demonstrated that sustained release of sphingosine 1-phosphate (S1P) from biodegradable polymers promotes microvascular network growth and arteriolar expansion. In this study, we employed S1P receptor-specific compounds to activate and antagonize different combinations of S1P receptors to elucidate those receptors most critical for promotion of pharmacologically induced microvascular network growth. We show that S1P1 and S1P3 receptors act synergistically to enhance functional network formation via increased functional length density, arteriolar diameter expansion, and increased vascular branching in the dorsal skinfold window chamber model. FTY720, a potent activator of S1P1 and S1P3, promoted a 107% and 153% increase in length density 3 and 7 days after implantation, respectively. It also increased arteriolar diameters by 60% and 85% 3 and 7 days after implantation. FTY720-stimulated branching in venules significantly more than unloaded poly(D, L-lactic-co-glycolic acid). When implanted on the mouse spinotrapezius muscle, FTY720 stimulated an arteriogenic response characterized by increased tortuosity and collateralization of branching microvascular networks. Our results demonstrate the effectiveness of S1P1 and S1P3 receptor-selective agonists (such as FTY720) in promoting microvascular growth for tissue engineering applications. PMID:20874260

  9. Does decompression of odontogenic cysts and cystlike lesions change the histologic diagnosis?

    PubMed

    Schlieve, Thomas; Miloro, Michael; Kolokythas, Antonia

    2014-06-01

    The purpose of this study was to report the histopathologic findings after postdecompression definitive treatment of odontogenic cystlike lesions and determine whether the diagnosis was consistent with the pretreatment diagnosis, thereby answering the clinical question: does decompression change the histologic diagnosis? The authors implemented a retrospective cohort study from a sample of patients diagnosed with a benign odontogenic cystlike lesion and who underwent decompression followed by definitive surgery as part of their treatment. The predictor variable was treatment by decompression and the dependent variable was change in histologic diagnosis. Age, gender, and lesion location were included as variables. The χ(2) test was used for statistical analysis of the categorical data and P values less than .05 were considered statistically significant. Twenty-five cysts and cystlike lesions in 25 patients were treated with decompression followed by enucleation and curettage. The mean age was 34 years (range, 13 to 80 yr) and 56% (14) were male patients. Lesions were located in the mandible in 76% (19 of 25) of patients. Postdecompression histologic examination at the time of definitive surgical treatment was consistent with the preoperative biopsy diagnosis in 91% (10 of 11) of keratocystic odontogenic tumors, 67% (2 of 3) of glandular odontogenic cysts, 75% (3 of 4) of dentigerous cysts, and 100% (7 of 7) of cystic ameloblastomas. The histologic diagnosis at time of definitive treatment by enucleation and curettage is consistent with the predecompression diagnosis. Therefore, all lesions should be definitively treated after decompression based on the initial lesion diagnosis, with all patients placed on appropriate follow-up protocols. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. All rights reserved.

  10. ORACLE Stroke Study: Opinion Regarding Acceptable Outcome Following Decompressive Hemicraniectomy for Ischemic Stroke.

    PubMed

    Honeybul, Stephen; Ho, Kwok M; Blacker, David W

    2016-08-01

    There continues to be considerable interest in the use of decompressive hemicraniectomy in the management of malignant cerebral artery infarction; however, concerns remain about long-term outcome. To assess opinion on consent and acceptable outcome among a wide range of healthcare workers. Seven hundred seventy-three healthcare workers at the 2 major public neurosurgical centers in Western Australia participated. Participants were asked to record their opinion on consent and acceptable outcome based on the modified Rankin Score (mRS). The evidence for clinical efficacy of the procedure was presented, and participants were then asked to reconsider their initial responses. Of the 773 participants included in the study, 407 (52.7%) initially felt that they would provide consent for a decompressive craniectomy as a lifesaving procedure, but only a minority of them considered an mRS score of 4 or 5 an acceptable outcome (for mRS score ≤4, n = 67, 8.7%; for mRS score = 4, n = 57, 7.4%). After the introduction of the concept of the disability paradox and the evidence for the clinical efficacy of decompressive craniectomy, more participants were unwilling to accept decompressive craniectomy (18.1% vs 37.8%), but at the same time, more were willing to accept an mRS score ≤4 as an acceptable outcome (for mRS score ≤4, n = 92, 11.9%; for mRS score = 4, n = 79, 10.2%). Most participants felt survival with dependency to be unacceptable. However, many would be willing to provide consent for surgery in the hopes that they may survive with some degree of independence. DESTINY, Decompressive Surgery for the Treatment of Malignant Infarction of the Middle Cerebral ArterymRS, modified Rankin Scale.

  11. Surgical Decompression of Painful Diabetic Peripheral Neuropathy: The Role of Pain Distribution

    PubMed Central

    Liao, Chenlong; Zhang, Wenchuan; Yang, Min; Ma, Qiufeng; Li, Guowei; Zhong, Wenxiang

    2014-01-01

    Objective To investigate the effect of surgical decompression on painful diabetic peripheral neuropathy (DPN) patients and discuss the role which pain distribution and characterization play in the management of painful DPN as well as the underlying mechanism involved. Methods A total of 306 patients with painful diabetic lower-extremity neuropathy were treated with Dellon surgical nerve decompression in our department. Clinical evaluation including Visual analogue scale (VAS), Brief Pain Inventory Short Form for diabetic peripheral neuropathy (BPI-DPN) questionnaire, two-point discrimination (2-PD), nerve conduction velocity (NCV) and high-resolution ultrasonography (cross-sectional area, CSA) were performed in all cases preoperatively, and at 6 month intervals for 2 years post-decompression. The patients who underwent surgery were retrospectively assigned into two subgroups (focal and diffuse pain) according to the distribution of the diabetic neuropathic pain. The control group included 92 painful DPN patients without surgery. Results The levels of VAS, scores in BPI-DPN, 2-PD, NCV results and CSA were all improved in surgical group when compared to the control group (P<0.05). More improvement of VAS, scores in BPI-DPN and CSA was observed in focal pain group than that in diffuse group (P<0.05). Conclusions Efficacy of decompression of multiple lower-extremity peripheral nerves in patients with painful diabetic neuropathy was confirmed in this study. While both focal and diffuse group could benefit from surgical decompression, pain relief and morphological restoration could be better achieved in focal group. PMID:25290338

  12. Potential and Limitations of Neural Decompression in Extreme Lateral Interbody Fusion-A Systematic Review.

    PubMed

    Lang, Gernot; Perrech, Moritz; Navarro-Ramirez, Rodrigo; Hussain, Ibrahim; Pennicooke, Brenton; Maryam, Farah; Avila, Mauricio J; Härtl, Roger

    2017-05-01

    Extreme lateral interbody fusion (ELIF) is a powerful tool for interbody fusion and coronal deformity correction. However, evidence regarding the success of ELIF in decompressing foraminal, lateral recess, and central canal stenosis is lacking. We performed a systematic review of current literature on the potential and limitations of ELIF to indirectly decompress neural elements. A literature search using PubMed, Cochrane, and ScienceDirect databases was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. Information on study design, sample size, population, procedure, number and location of involved levels, follow-up time, and complications as well as information on conflict of interest was extracted and evaluated. We selected 20 publications including 1080 patients for review. Most publications (90%) were retrospective case series. Most frequent indications for ELIF included degenerative disc disease, spinal stenosis, spondylolisthesis, and degenerative scoliosis. Most studies revealed significant improvement in radiographic and clinical outcome after ELIF. Mean foraminal area, central canal area, and subarticular diameter increased by 31.6 mm 2 , 28.5 mm 2 , and 0.85 mm. ELIF successfully improved foraminal stenosis. Contradictory results were found for indirect decompression of central canal stenosis. Data on lateral recess stenosis were scarce. Current data suggest ELIF to be an efficient technique in decompression of foraminal stenosis. Evidence on decompression of central canal or lateral recess stenosis via ELIF is low, and results are inconsistent. Most studies are limited by study design, sample size, and potential conflicts of interest. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Novel Biomarkers of Arterial and Venous Ischemia in Microvascular Flaps

    PubMed Central

    Nguyen, Gerard K.; Monahan, John F. W.; Davis, Gabrielle B.; Lee, Yong Suk; Ragina, Neli P.; Wang, Charles; Zhou, Zhao Y.; Hong, Young Kwon; Spivak, Ryan M.; Wong, Alex K.

    2013-01-01

    both diagnose and successfully treat microvascular complications before irreversible tissue damage and flap loss occurs. PMID:23977093

  14. Upcyte® Microvascular Endothelial Cells Repopulate Decellularized Scaffold

    PubMed Central

    Dally, Iris; Hartmann, Nadja; Münst, Bernhard; Braspenning, Joris; Walles, Heike

    2013-01-01

    A general problem in tissue engineering is the poor and insufficient blood supply to guarantee tissue cell survival as well as physiological tissue function. To address this limitation, we have developed an in vitro vascularization model in which a decellularized porcine small bowl segment, representing a capillary network within a collagen matrix (biological vascularized scaffold [BioVaSc]), is reseeded with microvascular endothelial cells (mvECs). However, since the supply of mvECs is limited, in general, and as these cells rapidly dedifferentiate, we have applied a novel technology, which allows the generation of large batches of quasi-primary cells with the ability to proliferate, whilst maintaining their differentiated functionality. These so called upcyte mvECs grew for an additional 15 population doublings (PDs) compared to primary cells. Upcyte mvECs retained endothelial characteristics, such as von Willebrandt Factor (vWF), CD31 and endothelial nitric oxide synthase (eNOS) expression, as well as positive Ulex europaeus agglutinin I staining. Upcyte mvECs also retained biological functionality such as tube formation, cell migration, and low density lipoprotein (LDL) uptake, which were still evident after PD27. Initial experiments using MTT and Live/Dead staining indicate that upcyte mvECs repopulate the BioVaSc Scaffold. As with conventional cultures, these cells also express key endothelial molecules (vWF, CD31, and eNOS) in a custom-made bioreactor system even after a prolonged period of 14 days. The combination of upcyte mvECs and the BioVaSc represents a novel and promising approach toward vascularizing bioreactor models which can better reflect organs, such as the liver. PMID:22799502

  15. Early Versus Delayed Surgical Decompression of Spinal Cord after Traumatic Cervical Spinal Cord Injury: A Cost-Utility Analysis.

    PubMed

    Furlan, Julio C; Craven, B Catharine; Massicotte, Eric M; Fehlings, Michael G

    2016-04-01

    This cost-utility analysis was undertaken to compare early (≤24 hours since trauma) versus delayed surgical decompression of spinal cord to determine which approach is more cost effective in the management of patients with acute traumatic cervical spinal cord injury (SCI). This study includes the patients enrolled into the Surgical Timing in Acute Spinal Cord Injury Study (STASCIS) and admitted at Toronto Western Hospital. Cases were grouped into patients with motor complete SCI and individuals with motor incomplete SCI. A cost-utility analysis was performed for each group of patients by the use of data for the first 6 months after SCI. The perspective of a public health care insurer was adopted. Costs were estimated in 2014 U.S. dollars. Utilities were estimated from the STASCIS. The baseline analysis indicates early spinal decompression is more cost-effective approach compared with the delayed spinal decompression. When we considered the delayed spinal decompression as the baseline strategy, the incremental cost-effectiveness ratio analysis revealed a saving of US$ 58,368,024.12 per quality-adjusted life years gained for patients with complete SCI and a saving of US$ 536,217.33 per quality-adjusted life years gained in patients with incomplete SCI for the early spinal decompression. The probabilistic analysis confirmed the early-decompression strategy as more cost effective than the delayed-decompression approach, even though there is no clearly dominant strategy. The results of this economic analysis suggests that early decompression of spinal cord was more cost effective than delayed surgical decompression in the management of patients with motor complete and incomplete SCI, even though no strategy was clearly dominant. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Applications of computational models to better understand microvascular remodelling: a focus on biomechanical integration across scales

    PubMed Central

    Murfee, Walter L.; Sweat, Richard S.; Tsubota, Ken-ichi; Gabhann, Feilim Mac; Khismatullin, Damir; Peirce, Shayn M.

    2015-01-01

    Microvascular network remodelling is a common denominator for multiple pathologies and involves both angiogenesis, defined as the sprouting of new capillaries, and network patterning associated with the organization and connectivity of existing vessels. Much of what we know about microvascular remodelling at the network, cellular and molecular scales has been derived from reductionist biological experiments, yet what happens when the experiments provide incomplete (or only qualitative) information? This review will emphasize the value of applying computational approaches to advance our understanding of the underlying mechanisms and effects of microvascular remodelling. Examples of individual computational models applied to each of the scales will highlight the potential of answering specific questions that cannot be answered using typical biological experimentation alone. Looking into the future, we will also identify the needs and challenges associated with integrating computational models across scales. PMID:25844149

  17. Microvascular Branching as a Determinant of Blood Flow by Intravital Particle Imaging Velocimetry

    NASA Technical Reports Server (NTRS)

    Parsons-Wingerter, Patricia; McKay, Terri L.; Vickerman, Mary B.; Wernet, Mark P.; Myers, Jerry G.; Radhakrishnan, Krishnan

    2007-01-01

    The effects of microvascular branching on blood flow were investigated in vivo by microscopic particle imaging velocimetry (micro-PIV). We use micro-PIV to measure blood flow by tracking red blood cells (RBC) as the moving particles. Velocity flow fields, including flow pulsatility, were analyzed for the first four branching orders of capillaries, postcapillary venules and small veins of the microvascular network within the developing avian yolksac at embryonic day 5 (E5). Increasing volumetric flowrates were obtained from parabolic laminar flow profiles as a function of increasing vessel diameter and branching order. Maximum flow velocities increased approximately twenty-fold as the function of increasing vessel diameter and branching order compared to flow velocities of 100 - 150 micron/sec in the capillaries. Results from our study will be useful for the increased understanding of blood flow within anastomotic, heterogeneous microvascular networks.

  18. Microvascular Reconstructive Surgery in Operations Iraqi and Enduring Freedom: the US Military Experience Performing Free Flaps in a Combat Zone

    DTIC Science & Technology

    2013-01-01

    Microvascular reconstructive surgery in Operations Iraqi and Enduring Freedom: The US military experience performing free flaps in a combat zone...usually must undergo reconstructive surgery in the combat zone. While the use of microvascular free-tissue transfer (free flaps) for traumatic... reconstruction iswell documented in the literature, various complicating factors exist when these intricate surgical procedures are performed in a theater of

  19. Effects of Riot Control Training on Systemic Microvascular Reactivity and Capillary Density.

    PubMed

    Pereira, Flavio; de Moraes, Roger; Van Bavel, Diogo; De Lorenzo, Andrea; Tibirica, Eduardo

    2018-03-14

    The main aim of the present study is to evaluate the effects of strenuous exercise, related to special military training for riot control, on systemic microvascular endothelial function and skin capillary density. Endothelium-dependent microvascular reactivity was evaluated in the forearm skin of healthy military trainees (age 23.4 ± 2.3 yr; n = 15) using laser speckle contrast imaging coupled with cutaneous acetylcholine (ACh) iontophoresis and post-occlusive reactive hyperemia (PORH). Functional capillary density was assessed using high-resolution, intra-vital color microscopy in the dorsum of the middle phalanx. Capillary recruitment (capillary reserve) was evaluated using PORH. Microcirculatory tests were performed before and after a 5-wk special military training for riot control. Microvascular endothelium-dependent vasodilatory responses were markedly and significantly reduced after training, compared with values obtained before training. The peak values of microvascular conductance obtained during iontophoresis of ACh or PORH before training (0.84 ± 0.22 and 0.94 ± 0.72 APU/mmHg, respectively) were markedly reduced after training (0.47 ± 0.11 and 0.71 ± 0.14 APU/mmHg; p < 0.0001 and p = 0.0037, respectively). Endothelium-dependent capillary recruitment was significantly reduced after training (before 101 ± 9 and after 95 ± 8 capillaries/mm2; p = 0.0007). The present study showed that a 5-wk strenuous military training, performed in unfavorable climatic conditions, induces marked systemic microvascular dysfunction, mainly characterized by reduced endothelium-dependent microvascular vasodilation and blunted capillary recruitment.

  20. Added Qualifications in Microsurgery: Consideration for Subspecialty Certification in Microvascular Surgery in Europe.

    PubMed

    Heidekrueger, Paul I; Tanna, Neil; Weichman, Katie E; Szpalski, Caroline; Tos, Pierluigi; Ninkovic, Milomir; Broer, P Niclas

    2016-07-01

    Background While implementation of subspecializations may increase expertise in a certain area of treatment, there also exist downsides. Aim of this study was, across several disciplines, to find out if the technique of microsurgery warrants the introduction of a "Certificate of Added Qualifications (CAQ) in microsurgery." Methods An anonymous, web-based survey was administered to directors of microsurgical departments in Europe (n = 205). Respondents were asked, among other questions, whether they had completed a 12-month microvascular surgery fellowship and whether they believed a CAQ in microvascular surgery should be instituted. Results The response rate was 57%, and 33% of the respondents had completed a 12-month microvascular surgery fellowship.A total of 61% of all surgeons supported a CAQ in microsurgery. Answers ranged from 47% of support to 100% of support, depending on the countries surveyed. Discussion This is one of the few reports to evaluate the potential role of subspecialty certification of microvascular surgery across several European countries. The data demonstrate that the majority of directors of microsurgical departments support such a certificate. There was significantly greater support for a CAQ in microsurgery among those who have completed a formal microvascular surgery fellowship themselves. Conclusion This study supports the notion that further discussion and consideration of subspecialty certification in microvascular surgery appears necessary. There are multiple concerns surrounding this issue. Similar to the evolution of hand surgery certification, an exploratory committee of executive members of the respective medical boards and official societies may be warranted. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  1. Maternal Engineered Nanomaterial Exposure and Fetal Microvascular Function: Does the Barker Hypothesis Apply?

    PubMed Central

    STAPLETON, Phoebe A.; MINARCHICK, Ms. Valerie C.; YI, Jinghai; ENGELS, Mr. Kevin; McBRIDE, Mr. Carroll R.; NURKIEWICZ, Timothy R.

    2013-01-01

    Objective The continued development and use of engineered nanomaterials (ENM) has given rise to concerns over the potential for human health effects. While the understanding of cardiovascular ENM toxicity is improving, one of the most complex and acutely demanding “special” circulations is the enhanced maternal system to support fetal development. The “Barker Hypothesis” proposes that fetal development within a hostile gestational environment may predispose/program future sensitivity. Therefore, the objective of this study was two-fold: 1) to determine if maternal ENM exposure alters uterine and/or fetal microvascular function and 2) test the Barker Hypothesis at the microvascular level. Study Design Pregnant (gestation day 10) Sprague-Dawley rats were exposed to nano-titanium dioxide aerosols (11.3±0.039 (mg/m3)*hour, 5 hours/day, 8.2±0.85 days) to evaluate the maternal and fetal microvascular consequences of maternal exposure. Microvascular tissue isolation (gestation day 20) and arteriolar reactivity studies (<150μm passive diameter) of the uterine premyometrial and fetal tail arteries were conducted. Results ENM exposures led to significant maternal and fetal microvascular dysfunction which presented as robustly compromised endothelium-dependent and -independent reactivity to pharmacologic and mechanical stimuli. Isolated maternal uterine arteriolar reactivity was consistent with a metabolically impaired profile and hostile gestational environment, impacting fetal weight. The fetal microvessels isolated from exposed dams demonstrate significant impairments to signals of vasodilation specific to mechanistic signaling and shear stress. Conclusion To our knowledge, this is the first report providing evidence that maternal ENM inhalation is capable of influencing fetal health, thereby supporting that the Barker Hypothesis is applicable at the microvascular level. PMID:23643573

  2. The effect of exercise training on cutaneous microvascular reactivity: A systematic review and meta-analysis.

    PubMed

    Lanting, Sean M; Johnson, Nathan A; Baker, Michael K; Caterson, Ian D; Chuter, Vivienne H

    2017-02-01

    This study aimed to review the efficacy of exercise training for improving cutaneous microvascular reactivity in response to local stimulus in human adults. Systematic review with meta-analysis. A systematic search of Medline, Cinahl, AMED, Web of Science, Scopus, and Embase was conducted up to June 2015. Included studies were controlled trials assessing the effect of an exercise training intervention on cutaneous microvascular reactivity as instigated by local stimulus such as local heating, iontophoresis and post-occlusive reactive hyperaemia. Studies where the control was only measured at baseline or which included participants with vasospastic disorders were excluded. Two authors independently reviewed and selected relevant controlled trials and extracted data. Quality was assessed using the Downs and Black checklist. Seven trials were included, with six showing a benefit of exercise training but only two reaching statistical significance with effect size ranging from -0.14 to 1.03. The meta-analysis revealed that aerobic exercise had a moderate statistically significant effect on improving cutaneous microvascular reactivity (effect size (ES)=0.43, 95% CI: 0.08-0.78, p=0.015). Individual studies employing an exercise training intervention have tended to have small sample sizes and hence lacked sufficient power to detect clinically meaningful benefits to cutaneous microvascular reactivity. Pooled analysis revealed a clear benefit of exercise training on improving cutaneous microvascular reactivity in older and previously inactive adult cohorts. Exercise training may provide a cost-effective option for improving cutaneous microvascular reactivity in adults and may be of benefit to those with cardiovascular disease and metabolic disorders such as diabetes. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  3. Inhaled nitric oxide pretreatment but not posttreatment attenuates ischemia-reperfusion-induced pulmonary microvascular leak.

    PubMed

    Chetham, P M; Sefton, W D; Bridges, J P; Stevens, T; McMurtry, I F

    1997-04-01

    Ischemia-reperfusion (I/R) pulmonary edema probably reflects a leukocyte-dependent, oxidant-mediated mechanism. Nitric oxide (NO) attenuates leukocyte-endothelial cell interactions and I/R-induced microvascular leak. Cyclic adenosine monophosphate (cAMP) agonists reverse and prevent I/R-induced microvascular leak, but reversal by inhaled NO (INO) has not been tested. In addition, the role of soluble guanylyl cyclase (sGC) activation in the NO protection effect is unknown. Rat lungs perfused with salt solution were grouped as either I/R, I/R with INO (10 or 50 ppm) on reperfusion, or time control. Capillary filtration coefficients (Kfc) were estimated 25 min before ischemia (baseline) and after 30 and 75 min of reperfusion. Perfusate cell counts and lung homogenate myeloperoxidase activity were determined in selected groups. Additional groups were treated with either INO (50 ppm) or isoproterenol (ISO-10 microM) after 30 min of reperfusion. Guanylyl cyclase was inhibited with 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ-15 microM), and Kfc was estimated at baseline and after 30 min of reperfusion. (1) Inhaled NO attenuated I/R-induced increases in Kfc. (2) Cell counts were similar at baseline. After 75 min of reperfusion, lung neutrophil retention (myeloperoxidase activity) and decreased perfusate neutrophil counts were similar in all groups. (3) In contrast to ISO, INO did not reverse microvascular leak. (4) 8-bromoguanosine 3',5'-cyclic monophosphate (8-br-cGMP) prevented I/R-induced microvascular leak in ODQ-treated lungs, but INO was no longer effective. Inhaled NO attenuates I/R-induced pulmonary microvascular leak, which requires sGC activation and may involve a mechanism independent of inhibition of leukocyte-endothelial cell interactions. In addition, INO is ineffective in reversing I/R-induced microvascular leak.

  4. Microvascular function in women with former gestational diabetes: A cohort study.

    PubMed

    Charwat-Resl, Silvia; Yarragudi, Rajashri; Heimbach, Moritz; Leitner, Karoline; Leutner, Michael; Gamper, Jutta; Giurgea, Georgiana-Aura; Mueller, Markus; Koppensteiner, Renate; Gschwandtner, Michael E; Kautzky-Willer, Alexandra; Schlager, Oliver

    2017-05-01

    In the long term, diabetes mellitus is potentially associated with the occurrence of microvascular damage. This study sought to assess whether a history of prior gestational diabetes mellitus is associated with long-term effects on the women's microcirculation. Within the scope of a long-term follow-up of the 'Viennese Post-Gestational Diabetes Project', women with prior gestational diabetes mellitus as well as women with previous pregnancy but with no history of gestational diabetes mellitus (controls) were enrolled in this cross-sectional study. Microvascular function was assessed by post-occlusive reactive hyperaemia using laser Doppler fluxmetry. Baseline perfusion, biological zero, peak perfusion, time to peak and recovery time were recorded and compared between both groups. Microvascular function was assessed in 55 women with prior gestational diabetes mellitus (46.1 ± 4.6 years) and 32 women with previous pregnancy but without prior gestational diabetes mellitus (42.9 ± 5.3 years). The mean period of time between delivery and the assessment of microvascular function was 16.2 ± 5.2 years in women with prior gestational diabetes mellitus group and 14.2 ± 4.8 years in controls. Regarding microvascular function, baseline perfusion, biological zero, peak perfusion, time to peak and recovery time did not differ between women with prior gestational diabetes mellitus and controls (all p > 0.05). In the long term, microvascular function appears not to be impaired in women with prior gestational diabetes mellitus.

  5. Microvascular endothelial function and cognitive performance: The ELSA-Brasil cohort study.

    PubMed

    Brant, Luisa; Bos, Daniel; Araujo, Larissa Fortunato; Ikram, M Arfan; Ribeiro, Antonio Lp; Barreto, Sandhi M

    2018-06-01

    Impaired microvascular endothelial function may be implicated in the etiology of cognitive decline. Yet, current data on this association are inconsistent. Our objective is to investigate the relation of microvascular endothelial function to cognitive performance in the ELSA-Brasil cohort study. A total of 1521 participants from ELSA-Brasil free of dementia underwent peripheral arterial tonometry (PAT) to quantify microvascular endothelial function (PAT-ratio and mean baseline pulse amplitude (BPA)) and cognitive tests that covered the domains of memory, verbal fluency, and executive function at baseline. Cognitive tests in participants aged 55 years old and above were repeated during the second examination (mean follow-up: 3.5 (0.3) years). Linear regression and generalized linear models were used to evaluate the association between endothelial function, global cognitive performance, and performance on specific cognitive domains. In unadjusted cross-sectional analyses, we found that BPA and PAT-ratio were associated with worse global cognitive performance (mean difference for BPA: -0.07, 95% CI: -0.11; -0.03, p<0.01; mean difference for PAT-ratio: 0.11, 95% CI: 0.01; 0.20, p=0.02), worse performance on learning, recall, and word recognition tests (BPA: -0.87, 95% CI: -1.21; -0.52, p<0.01; PAT-ratio: 1.58, 95% CI: 0.80; 2.36, p<0.01), and only BPA was associated with worse performance in verbal fluency tests (-0.70, 95% CI: -1.19; -0.21, p<0.01). Adjustments for age, sex, and level of education rendered the associations statistically non-significant. Longitudinally, there was no association between microvascular endothelial and cognitive functions. The associations between microvascular endothelial function and cognition are explained by age, sex, and educational level. Measures of microvascular endothelial function may be of limited value with regard to preclinical cognitive deficits.

  6. Assessment of macrovascular endothelial function using pulse wave analysis and its association with microvascular reactivity in healthy subjects.

    PubMed

    Ibrahim, N N I N; Rasool, A H G

    2017-08-01

    Pulse wave analysis (PWA) and laser Doppler fluximetry (LDF) are non-invasive methods of assessing macrovascular endothelial function and microvascular reactivity respectively. The aim of this study was to assess the correlation between macrovascular endothelial function assessed by PWA and microvascular reactivity assessed by LDF. 297 healthy and non-smoking subjects (159 females, mean age (±SD) 23.56 ± 4.54 years) underwent microvascular reactivity assessment using LDF followed by macrovascular endothelial function assessments using PWA. Pearson's correlation showed no correlation between macrovascular endothelial function and microvascular reactivity (r = -0.10, P = 0.12). There was no significant correlation between macrovascular endothelial function assessed by PWA and microvascular reactivity assessed by LDF in healthy subjects. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. The Eye as a Window to the Microvascular Complications of Diabetes.

    PubMed

    Zerbini, Gianpaolo; Maestroni, Silvia; Turco, Valentina; Secchi, Antonio

    2017-01-01

    Although microvascular complications of diabetes (retinopathy, neuropathy, and nephropathy) affect different organs, they are strongly correlated to each other. Based on recent data, their onset and progression could be directly monitored, focusing our attention only on the eye. When confirmed and standardized, this approach could allow one to simplify the way in which we follow the progression of different diabetic complications, and thus establish new strategies aimed at preventing, treating and, hopefully, inducing the remission of microvascular complications of diabetes. © 2017 S. Karger AG, Basel.

  8. Ethnic differences in microvascular function in apparently healthy South African men and women.

    PubMed

    Pienaar, P R; Micklesfield, L K; Gill, J M R; Shore, A C; Gooding, K M; Levitt, N S; Lambert, E V

    2014-07-01

    Microvascular dysfunction precedes the clinical manifestations of cardiovascular disease. Given the ethnic disparities in cardiovascular disease, we aimed to investigate ethnic differences in microvascular endothelial function in a group of young (18-33 years old), apparently healthy individuals (n = 33, nine Black African, 12 mixed ancestry and 12 Caucasian). Microvascular endothelium-dependent and -independent function was assessed by laser Doppler imagery and iontophoresis of ACh and sodium nitroprusside (SNP), respectively, adjusting for skin resistance. Microvascular reactivity was expressed as maximum absolute perfusion, percentage change from baseline and area under the curve (AUC). Skin resistance was significantly lower in the Caucasian group in response to ACh (Caucasian, mean 0.16 ± 0.03 Ω versus Black, 0.21 ± 0.04 Ω and mixed ancestry, 0.20 ± 0.02 Ω, P < 0.01) and SNP (Caucasian, 0.08 ± 0.01 Ω versus Black, 0.11 ± 0.02 Ω and mixed ancestry, 0.12 ± 0.01 Ω, P < 0.01). Microvascular function in response to ACh was significantly higher in the Caucasian group compared with the other two groups; however, after adjusting for skin resistance these differences were no longer significant. Conversely, the microvascular SNP response remained significantly higher in the Caucasian group, even after adjusting for skin resistance (P < 0.01). Diastolic blood pressure was inversely associated with the AUC of ACh (r = -0.4) and all SNP responses (r = -0.3 to -0.6). Skin resistance was inversely associated with AUC and maximum absolute ACh response (r = -0.59 and -0.64, respectively) and all SNP responses (r = -0.37 to -0.79). Ethnic differences in endothelium-independent microvascular function may contribute to ethnic disparities in cardiovascular disease. Moreover, skin resistance plays a significant role in the interpretation of the microvascular response to outcomes of iontophoresis in a multiethnic group. © 2014 The

  9. Intraocular pressure lowering effect of orbital decompression is related to increased venous outflow in Graves orbitopathy.

    PubMed

    Onaran, Zafer; Konuk, Onur; Oktar, Suna Özhan; Yücel, Cem; Unal, Mehmet

    2014-07-01

    To investigate the effects of combined orbital bone and fat decompression on intraocular pressure (IOP) and superior ophthalmic vein blood flow velocity (SOV-BFV), and their association with the clinical features of Graves orbitopathy (GO). During the 2002-2008 period, 72 eyes of 36 GO cases demonstrating moderate to severe orbitopathy were evaluated according to their clinical features as: cases with or without dysthyroid optic neuropathy (DON), and underwent orbital decompression. A control group comprised 40 eyes of 20 healthy subjects. In both groups, a full ophthalmic examination including IOP and Hertel measurements was performed, and SOV-BFV was analyzed with color Doppler imaging. Examinations were repeated after orbital decompression in GO patients. All the cases demonstrated clinical features of inactive disease. Among the patients 24 of 72 eyes (33.3%) showed clinical features of DON. After surgery, the mean decrease in Hertel values was 6.2 ± 1.8 mm (p = 0.001). The mean decrease in IOP was 3.0 ± 1.7 mmHg (from 17.3 ± 2.7 to 14.3 ± 2.0 mmHg) after orbital decompression where the post-operative values were comparable with the control group (12.9 ± 1.4 mmHg, p = 0.36). The mean increase in SOV-BFV achieved with decompression was 1.2 ± 0.6 cm/s (from 4.8 ± 1.7 to 6.0 ± 1.8 cm/s) and post-operative SOV-BFV values were also comparable with the control group (6.6 ± 1.3 cm/s, p = 0.26). The increase in SOV-BFV in cases with DON did not differ from cases without DON (p = 0.32), however, post-operative SOV-BFV of cases with DON was stil lower than cases without DON (p = 0.035). Combined orbital bone and fat decompression significantly reduced the IOP levels and increased the SOV-BFV in GO. This could be the confirmative finding of prediction that elevated IOP in GO is associated with increased episcleral venous pressure. The post-operative changes in IOP and SOV-BFV show differences

  10. Modified Veress needle decompression of tension pneumothorax: a randomized crossover animal study.

    PubMed

    Lubin, Dafney; Tang, Andrew L; Friese, Randall S; Martin, Matthew; Green, D J; Jones, Trevor; Means, Russell R; Ginwalla, Rashna; O'Keeffe, Terence S; Joseph, Bellal A; Wynne, Julie L; Kulvatunyou, Narong; Vercruysse, Gary; Gries, Lynn; Rhee, Peter

    2013-12-01

    The current prehospital standard of care using a large bore intravenous catheter for tension pneumothorax (tPTX) decompression is associated with a high failure rate. We developed a modified Veress needle (mVN) for this condition. The purpose of this study was to evaluate the effectiveness and safety of the mVN as compared with a 14-gauge needle thoracostomy (NT) in a swine tPTX model. tPTX was created in 16 adult swine via thoracic CO2 insufflation to 15 mm Hg. After tension physiology was achieved, defined as a 50% reduction of cardiac output, the swine were randomized to undergo either mVN or NT decompression. Failure to restore 80% baseline systolic blood pressure within 5 minutes resulted in crossover to the alternate device. The success rate of each device, death, and need for crossover were analyzed using χ. Forty-three tension events were created in 16 swine (24 mVN, 19 NT) at 15 mm Hg of intrathoracic pressure with a mean CO2 volume of 3.8 L. tPTX resulted in a 48% decline of systolic blood pressure from baseline and 73% decline of cardiac output, and 42% had equalization of central venous pressure with pulmonary capillary wedge pressure. All tension events randomized to mVN were successfully rescued within a mean (SD) of 70 (86) seconds. NT resulted in four successful decompressions (21%) within a mean (SD) of 157 (96) seconds. Four swine (21%) died within 5 minutes of NT decompression. The persistent tension events where the swine survived past 5 minutes (11 of 19 NTs) underwent crossover mVN decompression, yielding 100% rescue. Neither the mVN nor the NT was associated with inadvertent injuries to the viscera. Thoracic insufflation produced a reliable and highly reproducible model of tPTX. The mVN is vastly superior to NT for effective and safe tPTX decompression and physiologic recovery. Further research should be invested in the mVN for device refinement and replacement of NT in the field.

  11. Cancer Cells Regulate Biomechanical Properties of Human Microvascular Endothelial Cells*

    PubMed Central

    Mierke, Claudia Tanja

    2011-01-01

    Metastasis is a key event of malignant tumor progression. The capability to metastasize depends on the ability of the cancer cell to migrate into connective tissue, adhere, and possibly transmigrate through the endothelium. Previously we reported that the endothelium does not generally act as barrier for cancer cells to migrate in three-dimensional extracellular matrices (3D-ECMs). Instead, the endothelium acts as an enhancer or a promoter for the invasiveness of certain cancer cells. How invasive cancer cells diminish the endothelial barrier function still remains elusive. Therefore, this study investigates whether invasive cancer cells can decrease the endothelial barrier function through alterations of endothelial biomechanical properties. To address this, MDA-MB-231 breast cancer cells were used that invade deeper and more numerous into 3D-ECMs when co-cultured with microvascular endothelial cells. Using magnetic tweezer measurements, MDA-MB-231 cells were found to alter the mechanical properties of endothelial cells by reducing endothelial cell stiffness. Using spontaneous bead diffusion, actin cytoskeletal remodeling dynamics were shown to be increased in endothelial cells co-cultured with MDA-MB-231 cells compared with mono-cultured endothelial cells. In addition, knockdown of the α5 integrin subunit in highly transmigrating α5β1high cells derived from breast, bladder, and kidney cancer cells abolished the endothelial invasion-enhancing effect comparable with the inhibition of myosin light chain kinase. These results indicate that the endothelial invasion-enhancing effect is α5β1 integrin-dependent. Moreover, inhibition of Rac-1, Rho kinase, MEK kinase, and PI3K reduced the endothelial invasion-enhancing effect, indicating that signaling via small GTPases may play a role in the endothelial facilitated increased invasiveness of cancer cells. In conclusion, decreased stiffness and increased cytoskeletal remodeling dynamics of endothelial cells may account

  12. Successful Treatment of Early Talar Osteonecrosis by Core Decompression Combined with Intraosseous Stem Cell Injection: A Case Report.

    PubMed

    Nevalainen, Mika T; Repo, Jussi P; Pesola, Maija; Nyrhinen, Jukka P

    2018-01-01

    Osteonecrosis of the talus is a fairly rare condition. Many predisposing factors have been identified including previous trauma, use of corticosteroids, alcoholism, and smoking. As a gold standard, magnetic resonance imaging (MRI) is the most sensitive and specific diagnostic examination to detect osteonecrosis. While many treatment options for talar osteonecrosis exist, core decompression is suggested on young patients with good outcome results. More recently, intraosseous stem cell and platelet-rich plasma (PRP) injection has been added to the core decompression procedure. We report a successful treatment of early talar osteonecrosis ARCO I (Association Research Circulation Osseous) by core decompression combined with stem cell and PRP injection. On 3-month and 15-month follow-up, MRI showed complete resolution of the osteonecrotic changes together with clinical improvement. This modified technique is a viable treatment option for early talar osteonecrosis. Nevertheless, future prospects should include a study comparing this combined technique with plain core decompression.

  13. Factors associated with spinal fusion after posterior fossa decompression in pediatric patients with Chiari I malformation and scoliosis.

    PubMed

    Mackel, Charles E; Cahill, Patrick J; Roguski, Marie; Samdani, Amer F; Sugrue, Patrick A; Kawakami, Noriaki; Sturm, Peter F; Pahys, Joshua M; Betz, Randal R; El-Hawary, Ron; Hwang, Steven W

    2016-12-01

    OBJECTIVE The authors performed a study to identify clinical characteristics of pediatric patients diagnosed with Chiari I malformation and scoliosis associated with a need for spinal fusion after posterior fossa decompression when managing the scoliotic curve. METHODS The authors conducted a multicenter retrospective review of 44 patients, aged 18 years or younger, diagnosed with Chiari I malformation and scoliosis who underwent posterior fossa decompression from 2000 to 2010. The outcome of interest was the need for spinal fusion after decompression. RESULTS Overall, 18 patients (40%) underwent posterior fossa decompression alone, and 26 patients (60%) required a spinal fusion after the decompression. The mean Cobb angle at presentation and the proportion of patients with curves > 35° differed between the decompression-only and fusion cohorts (30.7° ± 11.8° vs 52.1° ± 26.3°, p = 0.002; 5 of 18 vs 17 of 26, p = 0.031). An odds ratio of 1.0625 favoring a need for fusion was established for each 1° of increase in Cobb angle (p = 0.012, OR 1.0625, 95% CI 1.0135-1.1138). Among the 14 patients older than 10 years of age with a primary Cobb angle exceeding 35°, 13 (93%) ultimately required fusion. Patients with at least 1 year of follow-up whose curves progressed more 10° after decompression were younger than those without curve progression (6.1 ± 3.0 years vs 13.7 ± 3.2 years, p = 0.001, Mann-Whitney U-test). Left apical thoracic curves constituted a higher proportion of curves in the decompression-only group (8 of 16 vs 1 of 21, p = 0.002). CONCLUSIONS The need for fusion after posterior fossa decompression reflected the curve severity at clinical presentation. Patients presenting with curves measuring > 35°, as well as those greater than 10 years of age, may be at greater risk for requiring fusion after posterior fossa decompression, while patients less than 10 years of age may require routine monitoring for curve progression. Left apical thoracic curves

  14. Intradiploic pseudomeningocele and ossified occipitocervical pseudomeningocele after decompressive surgery for Chiari I malformation: report of two cases and literature review.

    PubMed

    Kurzbuch, Arthur R; Magdum, Shailendra; Jayamohan, Jayaratnam

    2017-04-01

    Intradiploic cerebrospinal fluid (CSF) collections are rare findings. The authors describe two pediatric patients with iatrogenically induced occipital CSF collections after decompressive surgery for Chiari I malformation. The first patient presents a large occipital intradiploic pseudomeningocele and the second patient an intradiploic pseudomeningocele merging with an ossified occipitocervical pseudomeningocele. Though being rarities after decompression for Chiari I malformation, intradiploic fluid collection and ossified pseudomeningocele should be considered if patients represent with aggravating presurgical or new symptoms.

  15. Enhancement of KTP/532 laser disc decompression and arthroscopic microdiscectomy with a vital dye

    NASA Astrophysics Data System (ADS)

    Yeung, Anthony T.

    1993-07-01

    Currently, the clinical indications and results of arthroscopic microdiscectomy and laser disc decompression come close to, but do not exceed, the results of classic discectomy or microdiscectomy for the whole spectrum of surgical disc herniations. However, as minimally invasive techniques continue to evolve, results can be expected to equal or be potentially superior to conventional surgery. This exhibit demonstrates how the use of a vital dye can enhance standard arthroscopic microdiscectomy techniques and, when used in conjunction with KTP/532 laser disc decompression, allows for better arthroscopic visualization, documentation, and extraction of nucleus pulposus, ultimately expanding the current limiting criteria for minimally invasive techniques. When proper patient selection is combined with good clinical indications, the surgical results are rather dramatic, often achieving immediate relief of sciatica in the operating room.

  16. A new technique in reference based DNA sequence compression algorithm: Enabling partial decompression

    NASA Astrophysics Data System (ADS)

    Banerjee, Kakoli; Prasad, R. A.

    2014-10-01

    The whole gamut of Genetic data is ever increasing exponentially. The human genome in its base format occupies almost thirty terabyte of data and doubling its size every two and a half year. It is well-know that computational resources are limited. The most important resource which genetic data requires in its collection, storage and retrieval is its storage space. Storage is limited. Computational performance is also dependent on storage and execution time. Transmission capabilities are also directly dependent on the size of the data. Hence Data compression techniques become an issue of utmost importance when we confront with the task of handling such giganticdatabases like GenBank. Decompression is also an issue when such huge databases are being handled. This paper is intended not only to provide genetic data compression but also partially decompress the genetic sequences.

  17. Decompression Sickness During Simulated Low Pressure Exposure is Increased with Mild Ambulation Exercise

    NASA Technical Reports Server (NTRS)

    Pollock, N. W.; Natoli, M. J.; Martina, S. D.; Conkin, J.; Wessel, J. H., III; Gernhardt, M. L.

    2016-01-01

    Musculoskeletal activity accelerates inert gas elimination during oxygen breathing prior to decompression (prebreathe), but may also promote bubble formation (nucleation) and increase the risk of decompression sickness (DCS). The timing, pattern and intensity of musculoskeletal activity are likely critical to the net effect. The NASA Prebreathe Reduction Program (PRP) combined oxygen prebreathe and exercise preceding a 4.3 psia exposure in non-ambulatory subjects (a microgravity analog) to produce two protocols now used by astronauts preparing for extravehicular activity - one employing cycling and non-cycling exercise (CEVIS: 'cycle ergometer vibration isolation system') and one relying on non-cycling exercise only (ISLE: 'in-suit light exercise'). Current efforts investigate whether light exercise normal to 1 G environments increases the risk of DCS over microgravity simulation.

  18. Magma degassing triggered by static decompression at Kīlauea Volcano, Hawai‘i

    USGS Publications Warehouse

    Poland, Michael P.; Jeff, Sutton A.; Gerlach, Terrence M.

    2009-01-01

    During mid-June 2007, the summit of Kīlauea Volcano, Hawai‘i, deflated rapidly as magma drained from the subsurface to feed an east rift zone intrusion and eruption. Coincident with the deflation, summit SO2 emission rates rose by a factor of four before decaying to background levels over several weeks. We propose that SO2 release was triggered by static decompression caused by magma withdrawal from Kīlauea's shallow summit reservoir. Models of the deflation suggest a pressure drop of 0.5–3 MPa, which is sufficient to trigger exsolution of the observed excess SO2 from a relatively small volume of magma at the modeled source depth beneath Kīlauea's summit. Static decompression may also explain other episodes of deflation accompanied by heightened gas emission, including the precursory phases of Kīlauea's 2008 summit eruption. Hazards associated with unexpected volcanic gas emission argue for increased awareness of magma reservoir pressure fluctuations.

  19. Blood biochemical and cellular changes during decompression and simulated extravehicular activity

    NASA Technical Reports Server (NTRS)

    Jauchem, J. R.; Waligora, J. M.; Johnson, P. C. Jr

    1990-01-01

    Blood biochemical and cellular parameters were measured in human subjects before and after exposure to a decompression schedule involving 6 h of oxygen prebreathing. The exposure was designed to simulate extravehicular activity for 6 h (subjects performed exercise while exposed to 29.6 kPa). There were no significant differences between blood samples from subjects who were susceptible (n = 11) versus those who were resistant (n = 27) to formation of venous gas emboli. Although several statistically significant (P less than 0.05) changes in blood parameters were observed following the exposure (increases in white blood cell count, prothrombin time, and total bilirubin, and decreases in triglycerides, very-low-density lipoprotein cholesterol, and blood urea nitrogen), the changes were small in magnitude and blood factor levels remained within normal clinical ranges. Thus, the decompression schedule used in this study is not likely to result in blood changes that would pose a threat to astronauts during extravehicular activity.

  20. Effects of decompressive surgery on prognosis and cognitive deficits in herpes simplex encephalitis.

    PubMed

    Midi, Ipek; Tuncer, Nese; Midi, Ahmet; Mollahasanoglu, Aynur; Konya, Deniz; Sav, Aydin

    2007-01-01

    Herpes simplex encephalitis (HSE) is a serious viral infection with a high rate of mortality. The most commonly seen complications are behavioral changes, seizures and memory deficits. We report the case of a 37-year-old man with HSE in the right temporal lobe and a severe midline shift who was treated with acyclovir. The patient underwent anterior temporal lobe resection. Although HSE can cause permanent cognitive deficits, in this case, early surgical intervention minimized any deficit, as determined by detailed neuropsychological examination. Surgical decompression is indicated as early as possible in severe cases. This case report emphasizes the effect of surgical decompression for HSE on cognitive function, which has rarely been mentioned before.

  1. Effects of Decompressive Surgery on Prognosis and Cognitive Deficits in Herpes Simplex Encephalitis

    PubMed Central

    Midi, Ipek; Tuncer, Nese; Midi, Ahmet; Mollahasanoglu, Aynur; Konya, Deniz; Sav, Aydın

    2007-01-01

    Herpes simplex encephalitis (HSE) is a serious viral infection with a high rate of mortality. The most commonly seen complications are behavioral changes, seizures and memory deficits. We report the case of a 37-year-old man with HSE in the right temporal lobe and a severe midline shift who was treated with acyclovir. The patient underwent anterior temporal lobe resection. Although HSE can cause permanent cognitive deficits, in this case, early surgical intervention minimized any deficit, as determined by detailed neuropsychological examination. Surgical decompression is indicated as early as possible in severe cases. This case report emphasizes the effect of surgical decompression for HSE on cognitive function, which has rarely been mentioned before. PMID:18430984

  2. Needle decompression in a patient with vision-threatening orbital emphysema

    PubMed Central

    Lin, Che-Yu; Tsai, Chieh-Chih; Kao, Shu-Ching; Kau, Hui-Chuan; Lee, Fenq-Lih

    2016-01-01

    Orbital emphysema is a condition resulting from trapping of air in loose subcutaneous or orbital tissues from the paranasal sinuses. This condition commonly seen in patients with a history of periorbital trauma or surgery, especially following sneezing or nose blowing. It usually has a benign and self-limited course. However, the entrapped orbital air can cause a substantial increase in pressure with restricted ocular motility or vascular compromise and become severe enough to cause visual impairment. We herein present the case of a patient who developed severe orbital emphysema after blunt trauma followed by sneezing and was successfully treated with needle decompression of intraorbital air. Emergency needle decompression resulted in an improvement in vision and intraocular pressure. PMID:29018719

  3. Plagioclase nucleation and growth kinetics in a hydrous basaltic melt by decompression experiments

    NASA Astrophysics Data System (ADS)

    Arzilli, Fabio; Agostini, C.; Landi, P.; Fortunati, A.; Mancini, L.; Carroll, M. R.

    2015-12-01

    Isothermal single-step decompression experiments (at temperature of 1075 °C and pressure between 5 and 50 MPa) were used to study the crystallization kinetics of plagioclase in hydrous high-K basaltic melts as a function of pressure, effective undercooling (Δ T eff) and time. Single-step decompression causes water exsolution and a consequent increase in the plagioclase liquidus, thus imposing an effective undercooling (Δ T eff), accompanied by increased melt viscosity. Here, we show that the decompression process acts directly on viscosity and thermodynamic energy barriers (such as interfacial-free energy), controlling the nucleation process and favoring the formation of homogeneous nuclei also at high pressure (low effective undercoolings). In fact, this study shows that similar crystal number densities ( N a) can be obtained both at low and high pressure (between 5 and 50 MPa), whereas crystal growth processes are favored at low pressures (5-10 MPa). The main evidence of this study is that the crystallization of plagioclase in decompressed high-K basalts is more rapid than that in rhyolitic melts on similar timescales. The onset of the crystallization process during experiments was characterized by an initial nucleation event within the first hour of the experiment, which produced the largest amount of plagioclase. This nucleation event, at short experimental duration, can produce a dramatic change in crystal number density ( N a) and crystal fraction ( ϕ), triggering a significant textural evolution in only 1 h. In natural systems, this may affect the magma rheology and eruptive dynamics on very short time scales.

  4. Macrovascular Decompression of the Brainstem and Cranial Nerves: Evolution of an Anteromedial Vertebrobasilar Artery Transposition Technique.

    PubMed

    Choudhri, Omar; Connolly, Ian D; Lawton, Michael T

    2017-08-01

    Tortuous and dolichoectatic vertebrobasilar arteries can impinge on the brainstem and cranial nerves to cause compression syndromes. Transposition techniques are often required to decompress the brainstem with dolichoectatic pathology. We describe our evolution of an anteromedial transposition technique and its efficacy in decompressing the brainstem and relieving symptoms. To present the anteromedial vertebrobasilar artery transposition technique for macrovascular decompression of the brainstem and cranial nerves. All patients who underwent vertebrobasilar artery transposition were identified from the prospectively maintained database of the Vascular Neurosurgery service, and their medical records were reviewed retrospectively. The extent of arterial displacement was measured pre- and postoperatively on imaging. Vertebrobasilar arterial transposition and macrovascular decompression was performed in 12 patients. Evolution in technique was characterized by gradual preference for the far-lateral approach, use of a sling technique with muslin wrap, and an anteromedial direction of pull on the vertebrobasilar artery with clip-assisted tethering to the clival dura. With this technique, mean lateral displacement decreased from 6.6 mm in the first half of the series to 3.8 mm in the last half of the series, and mean anterior displacement increased from 0.8 to 2.5 mm, with corresponding increases in satisfaction and relief of symptoms. Compressive dolichoectatic pathology directed laterally into cranial nerves and posteriorly into the brainstem can be corrected with anteromedial transposition towards the clivus. Our technique accomplishes this anteromedial transposition from an inferolateral surgical approach through the vagoaccessory triangle, with sling fixation to clival dura using aneurysm clips. Copyright © 2017 by the Congress of Neurological Surgeons

  5. Analysis of the individual risk of altitude decompression sickness under repeated exposures

    NASA Technical Reports Server (NTRS)

    Kumar, K. Vasantha; Horrigan, David J.; Waligora, James M.; Gilbert, John H.

    1991-01-01

    In a case-control study, researchers examined the risk of decompression sickness (DCS) in individual subjects with higher number of exposures. Of the 126 subjects, 42 showed one or more episodes of DCS. Examination of the exposure-DCS relationship by odds ratio showed a linear relationship. Stratification analysis showed that sex, tissue ratio, and the presence of Doppler microbubbles were cofounders of this risk. A higher number of exposures increased the risk of DCS in this analysis.

  6. Management of sinonasal complications after endoscopic orbital decompression for Graves' orbitopathy.

    PubMed

    Antisdel, Jastin L; Gumber, Divya; Holmes, Janalee; Sindwani, Raj

    2013-09-01

    Endoscopic orbital decompression (EnOD) has proven to be safe and effective for the treatment of Graves' orbitopathy; however, complications do occur. Although the literature focuses on orbital complications, sinonasal complications including postobstructive sinusitis, hemorrhage, and cerebrospinal fluid (CSF) leak can also be challenging to manage. This study examines the incidence and management of sinonasal complications in these patients. Retrospective review. Clinical data, surgical findings, and postoperative outcomes were reviewed of patients who underwent EnOD for Graves' disease between March 2004 and November 2010. The incidence and management of postoperative sinonasal complications requiring an intervention were examined. The study group consisted of 50 consecutive patients (86 decompression procedures): 11 males and 39 females with an average age of 48.6 years (SD = 12.9). Incidence of significant sinonasal complications was 3.5% (5/86): with one patient experiencing postoperative hemorrhage requiring operative management, three patients with postoperative obstructive sinusitis, and one patient with nasal obstruction secondary to nasal adhesions that required lysis. The maxillary sinus was the most commonly involved and was managed using the mega-antrostomy technique. In the case of frontal sinusitis, an endoscopic transaxillary approach was utilized to avoid injury to decompressed orbital contents. All complications were successfully managed without sequelae. Sinonasal complications following EnOD are uncommon. In the setting of a decompressed orbit, even routine types of postoperative issues can be challenging and require additional considerations. Successful management of postoperative sinusitis related to outflow obstruction may require more extensive approaches and novel techniques. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  7. Minimally Invasive Transtubular Endoscopic Decompression for L5 Radiculopathy Induced by Lumbosacral Extraforaminal Lesions

    PubMed Central

    Kitamura, Takahiro; Masuda, Keigo; Hotta, Kensuke; Senba, Hideyuki; Shidahara, Satoshi

    2018-01-01

    Study Design Retrospective study. Purpose This study aimed to evaluate the efficacy of minimally invasive transtubular endoscopic decompression for the treatment of lumbosacral extraforaminal lesion (LSEFL). Overview of Literature Conventional procedures for surgical decompression for the treatment of LSEFL involve certain technical challenges because the lumbosacral extraforaminal region has unique anatomical features. Moreover, the efficacy of minimally invasive procedures performed via the posterolateral approach for LSEFL has been reported. Methods Twenty-five patients who had undergone minimally invasive transtubular endoscopic decompression for the treatment of LSEFL and could be followed up for at least 1 year postoperatively were enrolled. Five of these patients had a history of lumbar surgery, and seven had concomitant adjacent-level spinal stenosis. The clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) lumbar score, numeric rating scale (NRS), and the JOA Back Pain Evaluation Questionnaire (JOABPEQ). The mean postoperative follow-up (FU) duration was 3.8 years. Results All procedures could be completed without any severe surgical complications, and all patients could resume their previous activity level within 1 month postoperatively. The JOA score significantly increased from 14.1±4.0 at baseline to 23.1±3.7 at the 1-year FU and 22.1±3.8 at the last FU. Similarly, there were significant improvements in the postoperative NRS and JOABPEQ scores. An additional surgery was performed in two patients (8%) during the FU period. Patients with degenerative scoliosis exhibited significantly poorer outcomes compared with those without this condition. Conclusions Transtubular endoscopic decompression can overcome certain technical challenges involved in the conventional procedures for LSEFL treatment; therefore, it can be recommended as a useful procedure for treating LSEFL. This procedure can provide some benefits to LSEFL

  8. Cost-effectiveness of surgical decompression for space-occupying hemispheric infarction.

    PubMed

    Hofmeijer, Jeannette; van der Worp, H Bart; Kappelle, L Jaap; Eshuis, Sara; Algra, Ale; Greving, Jacoba P

    2013-10-01

    Surgical decompression reduces mortality and increases the probability of a favorable functional outcome after space-occupying hemispheric infarction. Its cost-effectiveness is uncertain. We assessed clinical outcomes, costs, and cost-effectiveness for the first 3 years in patients who were randomized to surgical decompression or best medical treatment within 48 hours after symptom onset in the Hemicraniectomy After Middle Cerebral Artery Infarction With Life-Threatening Edema Trial (HAMLET). Data on medical consumption were derived from case record files, hospital charts, and