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1

Arachidonic acid, an omega-6 fatty acid, induces cytoplasmic phospholipase A2 in prostate carcinoma cells.  

PubMed

For the past 60 years, dietary intake of essential fatty acids has increased. Moreover, the omega-6 fatty acids have recently been found to play an important role in regulation of gene expression. Proliferation of human prostate cells was significantly increased 48 h after arachidonic acid (AA) addition. We have analyzed initial uptake using nile red fluorescence and we found that the albumin conjugated AA is endocytosed into the cells followed by the induction of RNA within minutes, protein and PGE2 synthesis within hours. Here we describe that AA induces expression of cytosolic phospholipase A2 (cPLA2) in a dose-dependent manner and that this upregulation is dependent upon downstream synthesis of PGE2. The upregulation of cox-2 and cPLA2 was inhibited by flurbiprofen, a cyclooxygenase (COX) inhibitor, making this a second feed-forward enzyme in the eicosanoid pathway. Cox-2 specific inhibitors are known to inhibit colon and prostate cancer growth in humans; however, recent findings show that some of these have cardiovascular complications. Since cPLA2 is upstream in the eicosanoid pathway, it may be a good alternative for a pharmaceutical target for the treatment of cancer. PMID:15878913

Hughes-Fulford, Millie; Tjandrawinata, Raymond R; Li, Chai-Fei; Sayyah, Sina

2005-09-01

2

Activation of the central histaminergic system mediates arachidonic-acid-induced cardiovascular effects.  

PubMed

The aim of this study was to explain the involvement of the central histaminergic system in arachidonic acid (AA)-induced cardiovascular effects in normotensive rats using hemodynamic, immunohistochemistry, and microdialysis studies. Intracerebroventricularly (i.c.v.) administered AA (0.25, 0.5, and 1.0 ?mol) induced dose- and time-dependent increases in mean arterial pressure and decreased heart rate in conscious normotensive Sprague-Dawley rats. Central injection of AA (0.5 ?mol) also increased posterior hypothalamic extracellular histamine levels and produced strong COX-1 but not COX-2 immunoreactivity in the posterior hypothalamus of rats. Moreover, the cardiovascular effects and COX-1 immunoreactivity in the posterior hypothalamus induced by AA (0.5 ?mol; i.c.v.) were almost completely blocked by the H2 receptor antagonist ranitidine (50 and 100 nmol; i.c.v.) and partially blocked by the H1 receptor blocker chlorpheniramine (100 nmol; i.c.v.) and the H3-H4 receptor antagonist thioperamide (50 and 100 nmol; i.c.v.). In conclusion, these results indicate that centrally administered AA induces pressor and bradycardic responses in conscious rats. Moreover, we suggest that AA may activate histaminergic neurons and increase extracellular histamine levels, particularly in the posterior hypothalamus. Acting as a neurotransmitter, histamine is potentially involved in AA-induced cardiovascular effects under normotensive conditions. PMID:25065747

Altinbas, Burcin; Topuz, Bora Burak; Ilhan, Tuncay; Yilmaz, Mustafa Sertac; Erdost, Hatice; Yalcin, Murat

2014-08-01

3

Electroacupuncture at ST36-ST37 and at Ear Ameliorates Hippocampal Mossy Fiber Sprouting in Kainic Acid-Induced Epileptic Seizure Rats  

PubMed Central

Our previous study showed that mossy fiber sprouting can occur in the hippocampus region in rats 6?wk after kainic acid-induced epileptic seizure, and this mossy fiber sprouting can facilitate epileptogenesis. Transcutaneous auricular vagal nerve stimulation (VNS), which is similar to cervical VNS, can reduce the occurrence of epileptic seizure in intractable epilepsy patients. Greater parasympathetic nerve activity can be caused by 2?Hz electroacupuncture (EA). Therefore, we investigated the effect of 2?Hz EA at ST-36-ST37 and at the ear on mossy fiber sprouting in kainic-treated Sprague-Dawley rats. The results indicated that applying 2?Hz EA at ST36-ST37 and at the ear for 3?d per week over 6 consecutive weeks can ameliorate mossy fiber sprouting in the hippocampus region of rats. These results indicated that applying 2?Hz EA at ST36-ST37 and at the ear might be beneficial for the treatment and prevention of epilepsy in humans.

Lin, Yi-Wen; Liu, Hsu-Jan; Lin, Wan-Jung

2014-01-01

4

Arachidonic Acid-Induced Dilation in Human Coronary Arterioles: Convergence of Signaling Mechanisms on Endothelial TRPV4-Mediated Ca2+ Entry  

PubMed Central

Background Arachidonic acid (AA) and/or its enzymatic metabolites are important lipid mediators contributing to endothelium?derived hyperpolarizing factor (EDHF)–mediated dilation in multiple vascular beds, including human coronary arterioles (HCAs). However, the mechanisms of action of these lipid mediators in endothelial cells (ECs) remain incompletely defined. In this study, we investigated the role of the transient receptor potential vanilloid 4 (TRPV4) channel in AA?induced endothelial Ca2+ response and dilation of HCAs. Methods and Results AA induced concentration?dependent dilation in isolated HCAs. The dilation was largely abolished by the TRPV4 antagonist RN?1734 and by inhibition of endothelial Ca2+?activated K+ channels. In native and TRPV4?overexpressing human coronary artery ECs (HCAECs), AA increased intracellular Ca2+ concentration ([Ca2+]i), which was mediated by TRPV4?dependent Ca2+ entry. The AA?induced [Ca2+]i increase was inhibited by cytochrome P450 (CYP) inhibitors. Surprisingly, the CYP metabolites of AA, epoxyeicosatrienoic acids (EETs), were much less potent activators of TRPV4, and CYP inhibitors did not affect EET production in HCAECs. Apart from its effect on [Ca2+]i, AA induced endothelial hyperpolarization, and this effect was required for Ca2+ entry through TRPV4. AA?induced and TRPV4?mediated Ca2+ entry was also inhibited by the protein kinase A inhibitor PKI. TRPV4 exhibited a basal level of phosphorylation, which was inhibited by PKI. Patch?clamp studies indicated that AA activated TRPV4 single?channel currents in cell?attached and inside?out patches of HCAECs. Conclusions AA dilates HCAs through a novel mechanism involving endothelial TRPV4 channel?dependent Ca2+ entry that requires endothelial hyperpolarization, PKA?mediated basal phosphorylation of TRPV4, and direct activation of TRPV4 channels by AA.

Zheng, Xiaodong; Zinkevich, Natalya S.; Gebremedhin, Debebe; Gauthier, Kathryn M.; Nishijima, Yoshinori; Fang, Juan; Wilcox, David A.; Campbell, William B.; Gutterman, David D.; Zhang, David X.

2013-01-01

5

Cauliflower Ear  

MedlinePLUS

... it. Cauliflower ear occurs after someone gets a hit or repeated hits to the ear. Wrestlers and boxers are more ... have cauliflower ear because their ears may be hit while they're in a match. These blows ...

6

Ear Tubes  

MedlinePLUS

... are tiny cylinders placed through the ear drum (tympanic membrane) to allow air into the middle ear. They ... incision (small hole) in the ear drum or tympanic membrane. This is most often done under a surgical ...

7

Ear Pieces  

ERIC Educational Resources Information Center

In this article, the author describes an art project wherein students make fanciful connections between art and medicine. This project challenges students to interpret "ear idioms" (e.g. "blow it out your ear," "in one ear and out the other") by relying almost entirely on realistic ear drawings, the placement of them, marks, and values. In that…

DiJulio, Betsy

2011-01-01

8

[Elicitor activity of chitosan and arachidonic acid: their similarity and distinction].  

PubMed

Two elicitors-chitosan and arachidonic acid-induced the same defense responses in potatoes, stimulating the processes of wound reparation and inducing the formation of phytoalexins, inhibitors of proteinase, and active forms of oxygen. However, chitosan induced the defense potential of plant tissues at concentrations higher than those of arachidonic acid. The protective action of chitosan was defined by two parameters, i.e., the ability to induce the immune responses in plant tissues and to exhibit a toxic effect on the pathogen development, causing late blight and seedling blight, whereas the elicitor effect of arachidonic acid depended on its ability to induce the defense potential of plant tissues only. PMID:22567893

Vasiukova, N I; Gerasimova, N G; Chalenko, G I; Ozeretskovskaia, O L

2012-01-01

9

Swimmer's ear  

MedlinePLUS

... media) or upper respiratory infections such as colds. Swimming in polluted water can lead to swimmer's ear. ... the ear thoroughly after exposure to moisture. Avoid swimming in polluted water. Use earplugs when swimming. Consider ...

10

Elephant ear  

MedlinePLUS

Elephant ear plants are indoor or outdoor plants with very large, arrow-shaped leaves. Poisoning may occur ... Elephant ear grows naturally in tropical and subtropical areas, but is easily found in northern climates as ...

11

Ear wax  

MedlinePLUS

... water to drain. You may need to repeat irrigation several times. To avoid damaging your ear or ... who may remove the wax by: Repeating the irrigation attempts Suctioning the ear canal Using a small ...

12

Super Ears.  

ERIC Educational Resources Information Center

Presents an activity in which students design, construct, and test "super ears" to investigate sound and hearing. Students work in groups of three and explore how the outer ear funnels sound waves to the inner ear and how human hearing compares to that of other animals. (NB)

Thompson, Stan

1995-01-01

13

Ear Infections  

MedlinePLUS

... affects the middle ear and is called otitis media. The tubes inside the ears become clogged with fluid and mucus. This can affect hearing, because sound cannot get through all that fluid. If your child isn't old enough to say "My ear ...

14

Ear Biometrics  

Microsoft Academic Search

A new class of biometrics based upon ear features is introduced for use in the development of passive identification systems.\\u000a The availability of the proposed biometric is shown both theoretically in terms of the uniqueness and measurability over time\\u000a of the ear, and in practice through the implementation of a computer vision based system. Each subject’s ear is modeled as

Mark Burge; Wilhelm Burger

15

Ear wax  

PubMed Central

Introduction Ear wax only becomes a problem if it causes a hearing impairment or other ear-related symptoms. Ear wax is more likely to accumulate and cause a hearing impairment when normal extrusion is prevented — for example, by the use of hearing aids, or by the use of cotton buds to clean the ears. Ear wax can visually obscure the ear drum, and may need to be removed for diagnostic purposes. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of methods to remove ear wax? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2007 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found nine systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review, we present information relating to the effectiveness and safety of the following interventions: ear syringing; manual removal (other than ear syringing); and wax softeners (alone or prior to syringing).

2008-01-01

16

Animal Ears  

NSDL National Science Digital Library

This activity (page 2 of the PDF) is a full inquiry investigation into animal behavior and communication. Groups of learners will fashion a headband with fake ears, similar in shape to those of the animal they are going to observe. Then, they record observations of the animalâs reactions when a learner, wearing the ears in different positions, brings it a snack. Learners develop categories of behavior to organize and evaluate the results. Safety Note: an adult handler must be present if working with a horse or even a large dog. Relates to linked video, DragonflyTV: Horse Ears.

Twin Cities Public Television, Inc.

2006-01-01

17

Pierced Ears  

MedlinePLUS

... put ear cleaning solution, rubbing alcohol, or antibiotic ointment on them. Whoever is doing the cleaning should ... or swab to apply rubbing alcohol or antibiotic ointment to the earlobe or lobes. Gently rotate the ...

18

Ear Tubes  

MedlinePLUS

... Vaccines Hearing Loss and Ear Infection Find an ENT Last Name ZIP Code More Options About Otolaryngology ... United States. Otolaryngologists are commonly referred to as ENT physicians. Learn More Free Download AAO-HNS MarketPlace ...

19

Effects of NSAIDs on the Inner Ear: Possible Involvement in Cochlear Protection  

PubMed Central

Cyclooxygenase and lipoxygenase, two important enzymes involved in arachidonic acid metabolism, are major targets of non-steroidal anti-inflammatory drugs (NSAIDs). Recent investigations suggest that arachidonic cascades and their metabolites may be involved in maintaining inner ear functions. The excessive use of aspirin may cause tinnitus in humans and impairment of the outer hair cell functions in experimental animals. On the other hand, NSAIDs reportedly exhibit protective effects against various kinds of inner ear disorder. The present review summarizes the effects of NSAIDs on cochlear pathophysiology. NSAIDs are a useful ameliorative adjunct in the management of inner ear disorders.

Hoshino, Tomofumi; Tabuchi, Keiji; Hara, Akira

2010-01-01

20

Ear Cells  

NSDL National Science Digital Library

Spindly cells in the inner ear, called "hair" cells, are critical for both hearing and balance. Now, in a boon for research, neuro-scientists Jeffrey Corwin and Zhenqing Hu at the University of Virginia School of Medicine have finally grown and multiplied these cells in the lab.

Science Update (AAAS;)

2008-05-06

21

Ear Training  

NSDL National Science Digital Library

Using these websites, you can practice your ear training skills. There are links for intervals, chords, and short melodic segments. First, you should go to this website to practice intervals. Intervals Begin with the first option (simple intervals up). After mastering this, move to simple intervals down. As you become more advanced, continue down the line of interval options. They will become more difficult as you ...

2009-09-15

22

All-trans Arachidonic acid generates reactive oxygen species via xanthine dehydrogenase/xanthine oxidase interconversion in the rat liver cytosol in vitro  

PubMed Central

We previously reported that the all-cis isomer of arachidonic acid, the most naturally occurring isoform of this fatty acid, reduced cuprous copper ion-induced conversion of xanthine dehydrogenase into its reactive oxygen species generating form, xanthine oxidase. In the present study, the effects of all-trans isomer of arachidonic acid, in comparison with cis isomer of arachidonic acid, on the xanthine dehydrogenase/xanthine oxidase interconversion were explored. cis isomer of arachidonic acid alone did not have any significant effect on the activities of xanthine dehydrogenase and xanthine oxidase, but it inhibited the cuprous copper ion-induced conversion of xanthine dehydrogenase to xanthine oxidase in rat liver cytosol in vitro. In contrast, trans isomer of arachidonic acid elicited an increase in xanthine oxidase activity concomitant with a decrease in xanthine dehydrogenase activity, and further potentiated the cuprous copper ion-induced xanthine dehydrogenase/xanthine oxidase interconversion. In primary rat hepatocyte cultures, trans isomer of arachidonic acid increased 2',7'-dichlorofluorescein-fluorescence intensity in the cytosolic fraction from 2',7'-dichlorodihydrofluorescein, an indicator of reactive oxygen species generation. The pretreatment of allopurinol, an xanthine oxidase inhibitor, diminished the trans isomer of arachidonic acid-induced increase in the 2',7'-dichlorofluorescein-fluorescence intensity, indicating the role of xanthine dehydrogenase/xanthine oxidase in mediating trans isomer of arachidonic acid-induced reactive oxygen species generation. These observations suggest that, in contrast to all-cis arachidonic acid, all-trans arachidonic acid has the potential to enhance reactive oxygen species generation via xanthine dehydrogenase/xanthine oxidase interconversion in the liver cytosol in vitro.

Sakuma, Satoru; Kitamura, Takahiro; Kuroda, Chihiro; Takeda, Kanami; Nakano, Sayaka; Hamashima, Tomohiro; Kohda, Tetsuya; Wada, Shun-ichi; Arakawa, Yukio; Fujimoto, Yohko

2012-01-01

23

Boswellic acids stimulate arachidonic acid release and 12-lipoxygenase activity in human platelets independent of Ca2+ and differentially interact with platelet-type 12-lipoxygenase.  

PubMed

Boswellic acids inhibit the transformation of arachidonic acid to leukotrienes via 5-lipoxygenase but can also enhance the liberation of arachidonic acid in human leukocytes and platelets. Using human platelets, we explored the molecular mechanisms underlying the boswellic acid-induced release of arachidonic acid and the subsequent metabolism by platelet-type 12-li-poxygenase (p12-LO). Both beta-boswellic acid and 3-O-acetyl-11-keto-boswellic acid (AKBA) markedly enhanced the release of arachidonic acid via cytosolic phospholipase A2 (cPLA2), whereas for generation of 12-hydro(pero)xyeicosatetraenoic acid [12-H(P)ETE], AKBA was less potent than beta-boswellic acid and was without effect at higher concentrations (> or =30 microM). In contrast to thrombin, beta-boswellic acid-induced release of ara-chidonic acid and formation of 12-H(P)ETE was more rapid and occurred in the absence of Ca2+. The Ca2+-independent release of arachidonic acid and 12-H(P)ETE production elicited by beta-boswellic acid was not affected by pharmacological inhibitors of signaling molecules relevant for agonist-induced arachidonic acid liberation and metabolism. It is noteworthy that in cell-free assays, beta-boswellic acid increased p12-LO catalysis approximately 2-fold in the absence but not in the presence of Ca2+, whereas AKBA inhibited p12-LO activity. No direct modulatory effects of boswellic acids on cPLA2 activity in cell-free assays were evident. Therefore, immobilized KBA (linked to Sepharose beads) selectively precipitated p12-LO from platelet lysates but failed to bind cPLA2. Taken together, we show that boswellic acids induce the release of arachidonic acid and the synthesis of 12-H(P)ETE in human platelets by unique Ca2+-independent routes, and we identified p12-LO as a selective molecular target of boswellic acids. PMID:16788089

Poeckel, Daniel; Tausch, Lars; Kather, Nicole; Jauch, Johann; Werz, Oliver

2006-09-01

24

Inhibition by hydroxyachillin, sesquiterpene lactone from Tanacetum microphyllum , of PMA-induced mouse ear oedema  

Microsoft Academic Search

4--phorbol 12-myristate 13-acetate (PMA), when administered topically to mouse ear, induces a pronounced inflammatory response mediated by protein kinase C (PKC). Activation of PKC is implicated in the pathogenesis of inflammation, with phospholipase A2-dependent arachidonic acid release and eicosanoid production. We have investigated the effects of hydroxyachillin, a sesquiterpene lactone fromTanacetum microphyllum DC., on mouse ear oedema induced by PMA.

A. M. Silvfin; M. J. Abad; P. Bermejo; A. Villar

1996-01-01

25

Modulation of mouse ear edema by cyclooxygenase and lipoxygenase inhibitors and other pharmacologic agents  

Microsoft Academic Search

Inhibitors of arachidonic acid (AA) metabolism and other pharmacologic agents were evaluated against ear edema produced in mice by tetradecanoylphorbol acetate (TPA) or AA. Drugs were administered orally and topically either 30 min prior to AA or 30 min after TPA, except for steroids which were administered 2.5–3 hr prior to AA. Several cyclooxygenase (CO) inhibitors including indomethacin, aspirin, piroxicam

Richard P. Carlson; O'Neill-Davis Lynn; Joseph Chang; Alan J. Lewis

1985-01-01

26

Ringing in Your Ears?  

MedlinePLUS

... Ringing in Your Ears? Get the Buzz on Tinnitus Tinnitus is commonly described as a ringing in ... in Your Ears? Wise Choices Links What Causes Tinnitus? Several conditions can lead to tinnitus, including: Noise- ...

27

Ear infection - chronic  

MedlinePLUS

Middle ear infection - chronic; Otitis media - chronic; Chronic otitis media; Chronic ear infection ... Chole RA, Sudhoff HH. Chronic otitis media, mastoiditis, and ... eds. Otolaryngology: Head & Neck Surgery . 5th ed. Philadelphia, ...

28

Butyric acid induces apoptosis in inflamed fibroblasts.  

PubMed

Butyric acid, an extracellular metabolite from periodontopathic bacteria, induces apoptosis in murine and human T- and B-cells, whereas intact gingival fibroblasts isolated from healthy humans are resistant to butyric-acid-induced apoptosis. We examined the susceptibility of inflamed gingival fibroblasts isolated from adult persons with periodontitis to butyric-acid-induced apoptosis. Butyric acid significantly suppressed the viability of inflamed gingival fibroblasts and induced apoptosis in a dose-dependent manner. The incubation of inflamed gingival fibroblasts with butyric acid induced DNA fragmentation and apoptotic changes such as chromatin condensation, hypodiploid nuclei, and mitochondrial injury. Furthermore, butyric-acid-induced apoptosis in inflamed gingival fibroblasts was reduced by caspase-3/7, -6, -8, and -9 inhibitors. Thus, inflamed gingival fibroblasts from adult persons with periodontitis appear to be highly susceptible to mitochondria- and caspase-dependent apoptosis induced by butyric acid, compared with healthy gingival fibroblasts. PMID:18096893

Kurita-Ochiai, T; Seto, S; Suzuki, N; Yamamoto, M; Otsuka, K; Abe, K; Ochiai, K

2008-01-01

29

Poxvirus-induced alteration of arachidonate metabolism.  

PubMed Central

Recent evidence suggests that orthopoxviruses have an obligate requirement for arachidonic acid metabolites during replication in vivo and in vitro. Our report indicates that a virus family (Poxviridae) possesses multiple genes that function to regulate arachidonate metabolism. Analyses of BS-C-1 cells infected with cowpox virus or vaccinia virus detected enhanced arachidonate product formation from both the cyclooxygenase (specifically prostaglandins E2 and F2 alpha) and lipoxygenase (specifically 15-hydroxyeicosatetraenoic acid and 12-hydroxyeicosatetraenoic acid) pathways. In contrast, human parainfluenza type 3 or herpes simplex virus type 1 infections did not increase arachidonate metabolism. Results were consistent with a virus early-gene product either directly mediating or inducing a host factor that mediated the up-regulation of arachidonate metabolism, although vaccinia growth factor was not responsible. In addition, the cowpox virus 38-kDa protein-encoding gene, which is associated with inhibition of an inflammatory response, correlated with inhibition of formation of a product biochemically characteristic of (14R,15S)-dihydroxyeicosatetraenoic acid. We propose that orthopoxvirus-induced up-regulation of arachidonic acid metabolism during infection renders the infected cells susceptible to generation of inflammatory mediators from both the cyclooxygenase and the lipoxygenase pathways, and poxviruses, therefore, possess at least one gene (38K) that can alter the lipoxygenase-metabolite spectrum.

Palumbo, G J; Glasgow, W C; Buller, R M

1993-01-01

30

Pathology of the Ear  

PubMed Central

The external ear is exposed to weathering and trauma; it also has sparse vascularity, making it prone to infection and disease. The external location of the cutaneous ear makes it easily visible for diagnosis and accessible for treatment. In this article, the authors focus on diseases of the ear that are most commonly encountered and may be subject to surgical and medical evaluation and/or treatment. Epidemiology, pathogenesis, clinical course, and treatment for each disease entity are discussed.

Orengo, Ida; Robbins, Kerri; Marsch, Amanda

2011-01-01

31

Inhibition of arachidonic acid metabolism in colonic inflammation  

SciTech Connect

The authors have previously identified a lipoxygenase product profile in the acetic acid-induced model of colonic inflammation in the rat and have demonstrated utility of this model in evaluating inhibitors of arachidonic acid (AA) metabolism under in vitro conditions. They now demonstrate efficacy of an inhibitor of AA metabolism in this model under in vivo conditions. Male rats were pretreated with either nordihydroguaiaretic acid (NDGA) (50 mg/kg, p.o.) or vehicle for 3 consecutive days prior to induction of colonic inflammation with intraluminal administration of 2 mls of 5% acetic acid. After sacrifice, colonic mucosa was removed and incubated in the presence and absence of Ca/sup 2 +/ ionophore, A23187 (2 ..mu..M) for 5 min at 37/sup 0/C. Production of AA metabolites (LTB/sub 4/, 5-HETE, PGE/sub 2/, TxB/sub 2/) was determined by high pressure liquid chromatography and radioimmunoassay. NDGA treatment caused a significant inhibition of metabolite production (LTB/sub 4/, 5-HETE, PGE/sub 2/, TxB/sub 2/) compared to vehicle controls. This inhibition was evident in both ionophore-stimulated and non-stimulated samples. These results show that intestinal AA metabolism can be inhibited by in vivo drug administration and further suggest that this animal model may provide a simple means for evaluating potential therapies for inflammatory bowel disease.

Phyall, W.B.; Rush, J.A.; Fondacaro, J.D.

1986-03-01

32

Ear - blocked at high altitudes  

MedlinePLUS

... and blocked ears; Flying and blocked ears; Eustachian tube dysfunction -high altitude ... Yawning or swallowing usually opens the Eustachian tube, which ... to equalize in the ears. Performing them can unclog blocked ...

33

Ear tube insertion - series (image)  

MedlinePLUS

Ear tube insertion is recommended for: fluid in the middle ear (present for more than 12 weeks) recurrent ear ... the accumulated fluid is suctioned out. A small tube is inserted through the incised eardrum in order ...

34

Ear infection - acute  

MedlinePLUS

... more than 6 children) Changes in altitude or climate Cold climate Exposure to smoke Genetic factors (susceptibility to infection ... may be recommended if the person has a history of ear infections.

35

Ear Injuries (For Parents)  

MedlinePLUS

... head, sports injuries, and even listening to loud music can cause ear damage, which can affect hearing ... But for kids and teens, listening to loud music (at concerts, in the car, through headphones) is ...

36

Arachidonic acid metabolites in pathogenic yeasts  

PubMed Central

Although most of what is known about the biology and function of arachidonic acid metabolites comes from the study of mammalian biology, these compounds can also be produced by lower eukaryotes, including yeasts and other fungi. It is also in this group of organisms that the least is known about the metabolic pathways leading to the production of these compounds as well as the functions of these compounds in the biology of fungi and yeasts. This review will deal with the discovery of oxylipins from polyunsaturated fatty acids, and more specifically the arachidonic acid derived eicosanoids, such as 3-hydroxy eicosatetraenoic acid, prostaglandin F2? and prostaglandin E2, in yeasts starting in the early 1990s. This review will also focus on what is known about the metabolic pathways and/or proteins involved in the production of these compounds in pathogenic yeasts. The possible roles of these compounds in the biology, including the pathology, of these organisms will be discussed.

2012-01-01

37

Arachidonic Acid Metabolites in the Vasculature  

Microsoft Academic Search

\\u000a Early evidence that prostaglandins (PGs) or other arachidonic acid (AA) metabolites might play a role in blood vessels and\\u000a blood pressure regulation focused on the kidney (1). Hypertension accompanying the removal of the kidneys could not be attributed\\u000a to alterations in fluid and electrolyte function alone, for ureteral implantation into the vena cava created the same degree\\u000a of renal failure

Michael S. Golub; Mark T. Hori; Michael L. Tuck

38

Role of Lipoxygenase Metabolites of Arachidonic Acid in Enhanced Pulmonary Artery Contractions of Female Rabbits  

PubMed Central

Pulmonary arterial hypertension is characterized by elevated pulmonary artery pressure and vascular resistance. In women the incidence is 4 fold greater than that in men. Studies suggest sustained vasoconstriction is a factor in increased vascular resistance. Possible vasoconstrictor mediators include arachidonic acid-derived lipoxygenase metabolites. Our studies in rabbits showed enhanced endothelium-dependent contractions to arachidonic acid in pulmonary arteries from females compared to males. Because treatment with a non-specific lipoxygenase inhibitor reduced contractions in females but not males, the present study identified which lipoxygenase isoform contributes to sex-specific pulmonary artery vasoconstriction. 15- and 5- but not 12-lipoxygenase protein expression was greater in females. Basal and A23187-stimulated release of 15-, 5- and 12-hydroxyeicosatetraenoic acid from females and males was measured by liquid chromatography/mass spectrometry. Only 15-hydroxyeicosatetraenoic acid synthesis was greater in females compared to males under both basal and stimulated conditions. Vascular contractions to 15-hydroxyeicosatetraenoic acid were enhanced in females compared to males (maximal contraction; 44 ± 6% vs 25 ± 3%). The specific 15-lipoxygenase inhibitor PD146176 (12 ?mol/L) decreased arachidonic acid-induced contractions in females (maximal contraction; 93 ± 4% vs 57 ± 10%). If male pulmonary arteries were incubated with estrogen (1 ?mol/L, 18 hrs), protein expression of 15-lipoxygenase, and 15-hydroxyeicosatetraenoic acid production increased. Mechanisms to explain the increased incidence of pulmonary hypertension in women are not known. Results suggest the 15-lipoxygenase pathway is different between females and males and is regulated by estrogen. Understanding this novel sex-specific mechanism may provide insight into the increased incidence of pulmonary hypertension in females.

Pfister, Sandra L.

2011-01-01

39

Endoscopic middle ear surgery.  

PubMed

One hundred sixty-five middle ear procedures were performed with an endoscope, a camera, and a video monitor instead of the microscope. The endoscope offers the following advantages: 1) it visualizes the whole tympanic membrane and the ear canal without having to manipulate the patient's head or the microscope, 2) it extends the operative field in transcanal procedures into structures usually hidden from the microscope (anterior tympanic perforation, posterior retraction pocket, facial recess, and hypotympanum), and 3) it visualizes structures from multiple angles as opposed to the microscope's single axis along the ear canal. Disadvantages of the endoscope include the one-handed surgical technique, a loss of depth perception, limited magnification, and the need for training. The endoscope holds the greatest promise in tympanoplasty and cholesteatoma surgery and should increase the utilization of transcanal over postauricular procedures. PMID:9930539

Tarabichi, M

1999-01-01

40

Cholesteatoma of the Ear  

PubMed Central

Cholesteatoma is a hazardous condition because of the erosion and tissue destruction, which result in deafness, and the complications which threaten life. Early diagnosis and treatment provide the best opportunity for eradication of the disease and preservation of hearing. The patient usually complains of intermittent or persistent ear drainage and of diminished hearing acuity. Close examination of the tympanic membrane reveals a perforation, which at times may be quite small, with epithelial extension into the middle ear space. In most instances surgical intervention is necessary for eradication of the disease. ImagesFigure 1.

Thomas, Gary L.

1968-01-01

41

Arachidonic acid metabolites in experimental otitis media and effects of anti-inflammatory drugs.  

PubMed

Previous studies have shown that arachidonic acid (AA) metabolites are important in the pathogenesis of otitis media with effusion. The AA metabolites in 4 different experimental models for otitis media were analyzed, and the effect of anti-inflammatory drugs was studied. Purulent otitis media was induced in rats by inoculation of Streptococcus pneumoniae in the tympanic bulla, serous otitis media by blocking the tympanal orifice of the eustachian tube, and mucoid otitis media by combining the two procedures. Middle ear effusion was also induced by stimulating the external auditory canal with cold air. Indomethacin and hydrocortisone were used to inhibit AA metabolism in the latter model. Lipoxygenase products dominated in the purulent and cold air otitis media models. Cyclooxygenase products dominated in the mucoid and serous models. Indomethacin inhibited accumulation of middle ear effusion in the cold air otitis media model, whereas hydrocortisone did not. Apart from AA metabolites, other mechanisms and mediators appear to be responsible for the increased vessel permeability observed in the cold air otitis media model, such as interactions between mast cells and nerves in the middle ear mucosa. PMID:8285517

Goldie, P; Jung, T T; Hellström, S

1993-12-01

42

Cytochrome P450-dependent arachidonic acid metabolism in human kidney  

Microsoft Academic Search

Cytochrome P450-dependent arachidonic acid metabolism in human kidney. Cytochrome P450-dependent arachidonic acid metabolism in human kidney cortex from several postmortem subjects has been characterized. Using HPLC and GC\\/MS, four cytochrome P450-arachidonic acid metabolites were tentatively but not unequivocally identified as epoxyeicosatrienoic acid (EET), dihydroxyeicosatrienoic acid (DHT) and 19- and 20-hydroxyeicosatetraenoic acids, suggesting the involvement of two major cytochrome P450 enzymes,

Michal L Schwartzman; Pavel Martasek; Amelia R Rios; Richard D Levere; Karim Solangi; Alvin I Goodman; Nader G Abraham

1990-01-01

43

Ototoxicity (Ear Poisoning) (For Parents)  

MedlinePLUS

... part of the ear responsible for receiving/sending sounds and controlling balance — it's called ototoxicity or "ear ... have trouble hearing certain things, from high-pitched sounds to talking if there's background noise. Or they ...

44

The red ear syndrome.  

PubMed

Red Ear Syndrome (RES) is a very rare disorder, with approximately 100 published cases in the medical literature. Red ear (RE) episodes are characterised by unilateral or bilateral attacks of paroxysmal burning sensations and reddening of the external ear. The duration of these episodes ranges from a few seconds to several hours. The attacks occur with a frequency ranging from several a day to a few per year. Episodes can occur spontaneously or be triggered, most frequently by rubbing or touching the ear, heat or cold, chewing, brushing of the hair, neck movements or exertion. Early-onset idiopathic RES seems to be associated with migraine, whereas late-onset idiopathic forms have been reported in association with trigeminal autonomic cephalalgias (TACs). Secondary forms of RES occur with upper cervical spine disorders or temporo-mandibular joint dysfunction. RES is regarded refractory to medical treatments, although some migraine preventative treatments have shown moderate benefit mainly in patients with migraine-related attacks. The pathophysiology of RES is still unclear but several hypotheses involving peripheral or central nervous system mechanisms have been proposed. PMID:24093332

Lambru, Giorgio; Miller, Sarah; Matharu, Manjit S

2013-01-01

45

From Ear to Brain  

ERIC Educational Resources Information Center

In this paper Doreen Kimura gives a personal history of the "right-ear effect" in dichotic listening. The focus is on the early ground-breaking papers, describing how she did the first dichotic listening studies relating the effects to brain asymmetry. The paper also gives a description of the visual half-field technique for lateralized stimulus…

Kimura, Doreen

2011-01-01

46

The red ear syndrome  

PubMed Central

Red Ear Syndrome (RES) is a very rare disorder, with approximately 100 published cases in the medical literature. Red ear (RE) episodes are characterised by unilateral or bilateral attacks of paroxysmal burning sensations and reddening of the external ear. The duration of these episodes ranges from a few seconds to several hours. The attacks occur with a frequency ranging from several a day to a few per year. Episodes can occur spontaneously or be triggered, most frequently by rubbing or touching the ear, heat or cold, chewing, brushing of the hair, neck movements or exertion. Early-onset idiopathic RES seems to be associated with migraine, whereas late-onset idiopathic forms have been reported in association with trigeminal autonomic cephalalgias (TACs). Secondary forms of RES occur with upper cervical spine disorders or temporo-mandibular joint dysfunction. RES is regarded refractory to medical treatments, although some migraine preventative treatments have shown moderate benefit mainly in patients with migraine-related attacks. The pathophysiology of RES is still unclear but several hypotheses involving peripheral or central nervous system mechanisms have been proposed.

2013-01-01

47

An Efficient Ear Identification System  

Microsoft Academic Search

This paper proposes a robust ear identification system which is developed by fusing SIFT features of color segmented slice regions of an ear. It makes use of Gaussian mixture model (GMM) to build ear model with mixture of Gaussian using vector quantization algorithm and K-L divergence is applied to the GMM framework for recording the color similarity in the specified

Dakshina Ranjan Kisku; S. Gupta; P. Gupta; J. K. Sing

2010-01-01

48

Ear Biometrics in Computer Vision  

Microsoft Academic Search

A class of biometrics based upon ear features is introduced for use in the development of passive identification systems. The viability of the proposed biometric is shown both theoretically in terms of the uniqueness and measurability over time of the ear, and in practice through the implementation of a computer vision based system. Each subject's ear is modeled as an

Mark Burge; Wilhelm Burger

2000-01-01

49

Drug delivery to the ear.  

PubMed

Drug delivery to the ear is used to treat conditions of the middle and inner ear such as acute and chronic otitis media, Ménière's disease, sensorineural hearing loss and tinnitus. Drugs used include antibiotics, antifungals, steroids, local anesthetics and neuroprotective agents. A literature review was conducted searching Medline (1966-2012), Embase (1988-2012), the Cochrane Library and Ovid (1966-2012), using search terms 'drug delivery', 'middle ear', 'inner ear' and 'transtympanic'. There are numerous methods of drug delivery to the middle ear, which can be categorized as topical, systemic (intravenous), transtympanic and via the Eustachian tube. Localized treatments to the ear have the advantages of targeted drug delivery allowing higher therapeutic doses and minimizing systemic side effects. The ideal scenario would be a carrier system that could cross the intact tympanic membrane loaded with drugs or biochemical agents for the treatment of middle and inner ear conditions. PMID:23323784

Hoskison, E; Daniel, M; Al-Zahid, S; Shakesheff, K M; Bayston, R; Birchall, J P

2013-01-01

50

Differences in Arachidonic Acid Metabolism by Human Myelomonocytic Cell Lines.  

National Technical Information Service (NTIS)

The production of arachidonic acid metabolites by the HL60, ML3, and U937 human phagocyte cell lines was determined after incubation with interferon-gamma (IFN-gamma, 500 U/ml) or vehicle for 4 days. Cells were prelabeled with tritiated arachidonic acid, ...

M. C. Madden S. Becker H. S. Koren M. Friedman

1992-01-01

51

DIFFERENCES IN ARACHIDONIC ACID METABOLISM BY HUMAN MYELOMONCYTIC CELL LINES  

EPA Science Inventory

The production of arachidonic acid metabolites by the HL60, ML3, and U937 human phagocyte cell lines were determined after incubation with interferongamma (IFNg; 500 U/ml) or vehicle for 4 days. ells were prelabeled with tritiated arachidonic acid for 4 hours, and media supernata...

52

Human Ear Recognition in 3D  

Microsoft Academic Search

Human ear is a new class of relatively stable biometrics that has drawn researchers' attention recently. In this paper, we propose a complete human recognition system using 3D ear biometrics. The system consists of 3D ear detection, 3D ear identification, and 3D ear verification. For ear detection, we propose a new approach which uses a single reference 3D ear shape

Hui Chen; Bir Bhanu

2007-01-01

53

Arachidonic acid and ion channels: an update  

PubMed Central

Arachidonic acid (AA), a polyunsaturated fatty acid with four double bonds, has multiple actions on living cells. Many of these effects are mediated by an action of AA or its metabolites on ion channels. During the last 10 years, new types of ion channels, transient receptor potential (TRP) channels, store-operated calcium entry (SOCE) channels and non-SOCE channels have been studied. This review summarizes our current knowledge about the effects of AA on TRP and non-SOCE channels as well as classical ion channels. It aims to distinguish between effects of AA itself and effects of AA metabolites. Lipid mediators are of clinical interest because some of them (for example, leukotrienes) play a role in various diseases, others (such as prostaglandins) are targets for pharmacological therapeutic intervention.

Meves, H

2008-01-01

54

Save Your Ears  

NSDL National Science Digital Library

This game depicts a woman going through her day, faced with various loud sounds. In each situation, she has the choice of how to deal with the loud sound: Ear Plugs, Turn It Down, Move Away, or Do Nothing. You only have 3 of each choice available, symbolized by cards on screen. Your goal is to reach the end of the game with undamaged hearing and one set of earplugs, so you can enjoy an awesome rock concert. After each decision, you find out whether your hearing was damaged and if you made the best choice.

Omsi

2010-01-01

55

Hearing, Ear Infections, and Deafness  

MedlinePLUS

... How Loud is Too Loud? Ear Infections in Children Tinnitus Resources Statistics on Hearing, Balance, Ear Infections, and Deafness Free Publications Order Form Directory of Organizations NIDCD Glossary Student and Teacher Activities — Games, videos, and education materials Have a Question? You can ...

56

ANALYSIS OF ARACHIDONIC ACID METABOLITE AND PLATELET ACTIVATING FACTOR PRODUCTION  

EPA Science Inventory

Metabolites of arachidonic acid ("eicosanoids") and platelet activating factor are important bioactive lipids that may be involved in the pathobiological alterations in animals induced by pollutant exposure. nalysis of these substances in biological tissue and fluids is important...

57

D-2 dopamine receptor activation reduces free ( sup 3 H)arachidonate release induced by hypophysiotropic peptides in anterior pituitary cells  

SciTech Connect

Dopamine reduces the stimulation of intracellular ({sup 3}H)arachidonate release produced by the two PRL-stimulating peptides angiotensin-II and TRH. This effect is concentration dependent and is mediated by stimulation of D-2 dopamine receptors. D-2 receptor agonists (bromocriptine, dihydroergocryptine, and dihydroergocristine) inhibit the release of fatty acid induced by angiotensin-II with a potency that parallels their ability to inhibit PRL release in vitro. Conversely, the selective D-2 receptor antagonist L-sulpiride completely prevents dopamine's effect, whereas SCH 23390 (a D-1 receptor antagonist) is ineffective. The inhibitory action of dopamine does not seem to be consequent to an action on the adenylate cyclase-cAMP system, as 8-bromo-cAMP (1 mM) does not affect either basal or dopamine-inhibited ({sup 3}H)arachidonate release. However, a 24-h pertussis toxin pretreatment significantly reduces the action of dopamine on fatty acid release. Collectively, these results suggest that D-2 dopamine receptor-mediated inhibition of intracellular ({sup 3}H)arachidonate release requires the action of a GTP-binding protein, but is not a consequence of an inhibitory action on cAMP levels.

Canonico, P.L. (Univ. of Catania School of Medicine (Italy))

1989-09-01

58

Luteolin prevents uric acid-induced pancreatic ?-cell dysfunction  

PubMed Central

Abstract Elevated uric acid causes direct injury to pancreatic ?-cells. In this study, we examined the effects of luteolin, an important antioxidant, on uric acid-induced ?-cell dysfunction. We first evaluated the effect of luteolin on nitric oxide (NO) formation in uric acid-stimulated Min6 cells using the Griess method. Next, we performed transient transfection and reporter assays to measure transcriptional activity of nuclear factor (NF)-?B. Western blotting assays were also performed to assess the effect of luteolin on the expression of MafA and inducible NO synthase (iNOS) in uric acid-treated cells. Finally, we evaluated the effect of luteolin on uric acid-induced inhibition of glucose-stimulated insulin secretion (GSIS) in Min6 cells and freshly isolated mouse pancreatic islets. We found that luteolin significantly inhibited uric acid-induced NO production, which was well correlated with reduced expression of iNOS mRNA and protein. Furthermore, decreased activity of NF-?B was implicated in inhibition by luteolin of increased iNOS expression induced by uric acid. Besides, luteolin significantly increased MafA expression in Min6 cells exposed to uric acid, which was reversed by overexpression of iNOS. Moreover, luteolin prevented uric acid-induced inhibition of GSIS in both Min6 cells and mouse islets. In conclusion, luteolin protects pancreatic ?-cells from uric acid-induced dysfunction and may confer benefit on the protection of pancreatic ?-cells in hyperuricemia-associated diabetes.

Ding, Ying; Shi, Xuhui; Shuai, Xuanyu; Xu, Yuemei; Liu, Yun; Liang, Xiubin; Wei, Dong; Su, Dongming

2014-01-01

59

Autoimmune Inner Ear Disease (AIED)  

MedlinePLUS

... Disease.” Current Opinion in Rheumatology, 12:32–40, 2000. Click here to download the "Autoimmune Inner Ear Disease" publication. Make a donation Become a member Balance Awareness Week Sponsor Message ...

60

Glue ear: the new dyslexia?  

PubMed Central

Several factors have led to the current epidemic of surgery for glue ear in children, including the widespread introduction of audiometry; greater recognition of the presence of fluid in the middle ear by general practitioners; the availability of more otolaryngologists; and technical advances such as the availability of antibiotics to treat postoperative infections and of flanged tympanostomy tubes (grommets). The need of surgeons to fill the vacuum caused by the decline in the number of adenotonsillectomies, and the fact that a diagnosis of glue ear legitimises the continued use of these operations, may also have contributed to the increase. Finally, glue ear may provide parents with a medical explanation of their children's poor educational performance, as the term dyslexia did in the past. The high social and public costs of this operation demand a reappraisal of its increasing use.

Black, N

1985-01-01

61

Salicylic acid-induced hepatotoxicity triggered by oxidative stress  

Microsoft Academic Search

Salicylic acid is a widely used nonsteroidal anti-inflammatory drug (NSAID). But it is known to cause serious liver damage occasionally. Mitochondrial dysfunction and oxidative stress are predicted to be the major factors of salicylic acid-induced liver injury. We investigated the influence of salicylic acid on ATP contents, oxygen consumption and lipid peroxidation in the presence of the same concentration of

Hirokazu Doi; Toshiharu Horie

2010-01-01

62

Ear disorders in scuba divers.  

PubMed

History of underwater diving dates back to antiquity. Breath-hold technique in diving was known to the ancient nations. However, deep diving progressed only in the early decades of the 19th century as the result of advancements in efficient underwater technologies which subsequently led to invention of sophisticated sets of scuba diving in the 20th century. Currently, diving is performed for various purposes including commercial, recreational, military, underwater construction, oil industry, underwater archeology and scientific assessment of marine life. By increasing popularity of underwater diving, dive-related medical conditions gradually became more evident and created a new challenge for the health care professionals, so that eventually, a specialty the so-called "diving medicine" was established. Most of the diving-associated disorders appear in the head and neck. The most common of all occupational disorders associated with diving are otologic diseases. External otitis has been reported as the most common otolaryngologic problem in underwater divers. Exostosis of the external ear canal may be formed in divers as the result of prolonged diving in cold waters. Other disorders of the ear and paranasal sinuses in underwater divers are caused by barometric pressure change (i.e., barotraumas), and to a lesser extent by decompression sickness. Barotrauma of the middle ear is the most prevalent barotrauma in divers. The inner ear barotraumas, though important, is less common. The present paper is a brief overview of diving-related ear disorders particularly in scuba divers. PMID:23022815

Azizi, M H

2011-01-01

63

3D printed bionic ears.  

PubMed

The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C

2013-06-12

64

The emotional ear in stress.  

PubMed

Stress of some kind is encountered everyday and release of stress hormones is essential for adaptation to change. Stress can be physical (pain, noise exposure, etc.), psychological (apprehension to impending events, acoustic conditioning, etc.) or due to homeostatic disturbance (hunger, blood pressure, inner ear pressure, etc.). Persistent elevated levels of stress hormones can lead to disease states. The aim of the present review is to bring together data describing morphological or functional evidence for hormones of stress within the inner ear. The present review describes possible multiple interactions between the sympathetic and the complex feed-back neuroendocrine systems which interact with the immune system and so could contribute to various inner ear dysfunctions such as tinnitus, vertigo, hearing losses. Since there is a rapidly expanding list of genes specifically expressed within the inner ear this clearly allows for possible genomic and non-genomic local action of steroid hormones. Since stress can be encountered at any time throughout the life-time, the effects might be manifested starting from in-utero. These are avenues of research which remain relatively unexplored which merit further consideration. Progress in this domain could lead towards integration of stress concept into the overall clinical management of various inner ear pathologies. PMID:14505685

Horner, K C

2003-08-01

65

3D Printed Bionic Ears  

PubMed Central

The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the precise anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.

Mannoor, Manu S.; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A.; Soboyejo, Winston O.; Verma, Naveen; Gracias, David H.; McAlpine, Michael C.

2013-01-01

66

Tuning in the bullfrog ear.  

PubMed Central

When electrical resonances were observed in acoustic sensory cells of lower vertebrates, the hearing research community was presented with the exciting possibility that tuning in the ears of those animals might be explained directly in terms of familiar molecular devices. It is reported here that in the frog sacculus, where electrical resonances have been observed in isolated hair cells, the effects of those resonances are completely obscured in the tuning properties of the sacculus in the intact ear. This observation has important implications not only for students of the ear, but for reductionist biologists in general. All of the dynamic properties of a system of connected, bidirectional processes are consequences of all of those processes at once; in such a system, the properties of an experimentally isolated subsystem may be totally obscured in the operation of the system as a whole.

Lewis, E R

1988-01-01

67

EFFECTS OF PHOSGENE EXPOSURE ON LUNG ARACHIDONIC ACID METABOLISM  

EPA Science Inventory

Phosgene is a pulmonary toxicant that can produce lung edema, bronchoconstriction, and immune suppression following an acute exposure. he response of the lung to phosgene inhalation may be mediated through alternations in the metabolism of arachidonic acid to the biologically pot...

68

Dynamic Simulations on the Arachidonic Acid Metabolic Network  

Microsoft Academic Search

Drug molecules not only interact with specific targets, but also alter the state and function of the associated biological network. How to design drugs and evaluate their functions at the systems level becomes a key issue in highly efficient and low–side-effect drug design. The arachidonic acid metabolic network is the network that produces inflammatory mediators, in which several enzymes, including

Kun Yang; Wenzhe Ma; Huanhuan Liang; Qi Ouyang; Chao Tang; Luhua Lai

2007-01-01

69

Inner Ear Drug Delivery for Auditory Applications  

PubMed Central

Many inner ear disorders cannot be adequately treated by systemic drug delivery. A blood-cochlear barrier exists, similar physiologically to the blood-brain barrier, which limits the concentration and size of molecules able to leave the circulation and gain access to the cells of the inner ear. However, research in novel therapeutics and delivery systems has led to significant progress in the development of local methods of drug delivery to the inner ear. Intratympanic approaches, which deliver therapeutics to the middle ear, rely on permeation through tissue for access to the structures of the inner ear, whereas intracochlear methods are able to directly insert drugs into the inner ear. Innovative drug delivery systems to treat various inner ear ailments such as ototoxicity, sudden sensorineural hearing loss, autoimmune inner ear disease, and for preserving neurons and regenerating sensory cells are being explored.

Swan, Erin E. Leary; Mescher, Mark J.; Sewell, William F.; Tao, Sarah L.; Borenstein, Jeffrey T.

2008-01-01

70

Physiological functioning of the ear and masking  

NASA Technical Reports Server (NTRS)

The physiological functions of the ear and the role masking plays in speech communication are examined. Topics under investigation include sound analysis of the ear, the aural reflex, and various types of noise masking.

1984-01-01

71

21 CFR 878.3590 - Ear prosthesis.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3590 Ear prosthesis. (a) Identification. An ear prosthesis is a...

2013-04-01

72

Mechanics of the frog ear  

PubMed Central

The frog inner ear contains three regions that are sensitive to airborne sound and which are functionally distinct. (1) The responses of nerve fibres innervating the low-frequency, rostral part of the amphibian papilla (AP) are complex. Electrical tuning of hair cells presumably contributes to the frequency selectivity of these responses. (2) The caudal part of the AP covers the mid-frequency portion of the frog's auditory range. It shares the ability to generate both evoked and spontaneous otoacoustic emissions with the mammalian cochlea and other vertebrate ears. (3) The basilar papilla functions mainly as a single auditory filter. Its simple anatomy and function provide a model system for testing hypotheses concerning emission generation. Group delays of stimulus frequency otoacoustic emissions (SFOAEs) from the basilar papilla are accounted for by assuming that they result from forward and reverse transmission through the middle ear, a mechanical delay due to tectorial membrane filtering and a rapid forward and reverse propagation through the inner ear fluids, with negligible delay.

van Dijk, Pim; Mason, Matthew J.; Schoffelen, Richard L. M.; Narins, Peter M.; Meenderink, Sebastiaan W. F.

2010-01-01

73

Middle Ear Infections (For Parents)  

MedlinePLUS

... speak. Sound, which is made up of invisible waves of energy, causes these vibrations. Every time you hear a sound, the various structures of the ear have to work together to make sure ... Hearing begins when sound waves that travel through the air reach the outer ...

74

Reconstruction of middle ear malformations.  

PubMed

Malformations of the middle ear are classified as minor and major malformations. Minor malformations appear with regular external auditory canal, tympanic membrane and aerated middle ear space. The conducting hearing loss is due to fixation or interruption of the ossicular chain. The treatment is surgical, following the rules of ossiculoplasty and stapes surgery. In major malformations (congenital aural atresia) there is no external auditory canal and a deformed or missing pinna. The mastoid and the middle ear space may be underdevelopped, the ossicular chain is dysplastic. Surgical therapy is possible in patients with good aeration of the temporal bone, existing windows, a near normal positioned facial nerve and a mobile ossicular chain. Plastic and reconstructive surgery of the pinna should proceed the reconstruction of the external auditory canal and middle ear. In cases of good prognosis unilateral aural atresia can be approached already in childhood. In patients with high risk of surgical failure, bone anchored hearing aids are the treatment of choice. Recent reports of implantable hearing devices may be discussed as an alternative treatment for selected patients. PMID:22073077

Schwager, Konrad

2007-01-01

75

Chronic clozapine reduces rat brain arachidonic acid metabolism by reducing plasma arachidonic acid availability  

PubMed Central

Chronic administration of mood stabilizers to rats downregulates the brain arachidonic acid (AA) cascade. This downregulation may explain their efficacy against bipolar disorder (BD), in which brain AA cascade markers are elevated. The atypical antipsychotics, olanzapine (OLZ) and clozapine (CLZ), also act against BD. When given to rats, both reduce brain cyclooxygenase activity and prostaglandin E2 concentration; OLZ also reduces rat plasma unesterified and esterified AA concentrations, and AA incorporation and turnover in brain phospholipid. To test whether CLZ produces similar changes, we used our in vivo fatty acid method in rats given 10 mg/kg/day i.p. CLZ, or vehicle, for 30 days; or 1 day after CLZ washout. [1-14C]AA was infused intravenously for 5 min, arterial plasma was collected and microwaved brain was analyzed. CLZ increased incorporation coefficients ki? and rates Jin,i of plasma unesterified AA into brain phospholipids i, while decreasing plasma unesterified but not esterified AA. These effects disappeared after washout. Thus, CLZ and OLZ similarly downregulated kinetics and cyclooxygenase expression of the brain AA cascade, likely by reducing plasma unesterified AA availability. Atypical antipsychotics and mood stabilizers may be therapeutic in BD by downregulating, indirectly or directly respectively, the elevated brain AA cascade of that disease.

Modi, Hiren R.; Taha, Ameer Y.; Kim, Hyung-Wook; Chang, Lisa; Rapoport, Stanley I.; Cheon, Yewon

2012-01-01

76

Contour Matching for 3D Ear Recognition  

Microsoft Academic Search

Ear is a new class of relatively stable biometric that is invariant from childhood to early old age (8 to 70). It is not affected with facial expressions, cosmetics and eye glasses. In this paper, we introduce a two-step ICP (Iterative Closest Point) algorithm for matching 3D ears. In the first step, the helix of the ear in 3D images

Hui Chen; Bir Bhanu

2005-01-01

77

Can Loud Music Hurt My Ears?  

MedlinePLUS

... Fresh Lunches The Pink Locker Society Can Loud Music Hurt My Ears? KidsHealth > Kids > Q&A > Q & A > Can Loud Music Hurt My Ears? Print A A A Text ... up? Oh! You want to know if loud music can hurt your ears . Are you asking because ...

78

Immunologic Disorders of the Inner Ear.  

ERIC Educational Resources Information Center

Immune inner ear disease represents a series of immune system mediated problems that can present with hearing loss, dizziness, or both. The etiology, presentation, testing, and treatment of primary immune inner ear disease is discussed. A review of secondary immune inner ear disease is presented for comparison. (Contains references.) (Author/CR)

Kinney, William C.; Hughes, Gordon B.

1997-01-01

79

Intraluminal calcium binding does not mediate fatty acid-induced pancreatic bicarbonate secretion  

Microsoft Academic Search

Summary  Since the chain length dependency of fatty acid-induced pancreatic exocrine secretion parallels that of fatty acid-induced\\u000a inhibition of gastric emptying, similar mechanisms of action may be involved. An earlier study suggested that binding of calcium\\u000a might mediate fatty acid-induced inhibition of gastric emptying. This study investigated possible mediation of fatty acid-induced\\u000a pancreatic secretion by calcium binding. Pancreatic secretory response to

Aaron S. Fink; Mark Irving; James H. Meyer

1989-01-01

80

Salicylic acid-induced hepatotoxicity triggered by oxidative stress.  

PubMed

Salicylic acid is a widely used nonsteroidal anti-inflammatory drug (NSAID). But it is known to cause serious liver damage occasionally. Mitochondrial dysfunction and oxidative stress are predicted to be the major factors of salicylic acid-induced liver injury. We investigated the influence of salicylic acid on ATP contents, oxygen consumption and lipid peroxidation in the presence of the same concentration of salicylic acid. Leakage of lactate dehydrogenase (LDH) was significantly higher in the presence of 5mM salicylic acid than in its absence. Salicylic acid-induced thiobarbituric acid-reactive substance (TBARS) formation and spontaneous chemiluminescence (CL) in rat hepatocytes, whereas antioxidants, such as promethazine (PMZ) and N,N-diphenylphenylenediamine (DPPD), suppressed both TBARS formation and LDH leakage. TBARS formation in rat liver microsomes was suppressed by diethyldithiocarbamate (a specific inhibitor of cytochrome P450 (CYP)2E1) and diclofenac (a specific inhibitor of CYP2C11). These results suggest that salicylic acid-induced lipid peroxidation was related to oxidative metabolism mediated by CYP2E1 and CYP2C11. On the other hand, 5mM salicylic acid induced a drastic decrease of ATP contents in rat isolated hepatocytes. Furthermore, mitochondrial respiration control ratio (RC ratio), calculated by State 3/State 4 also decreased with the increase of salicylic acid concentration. These findings suggest that salicylic acid would trigger mitochondrial dysfunction and cause ATP decrease, leading to lethal liver cell injury by lipid peroxidation, although this hypothesis remains to be elucidated in vivo. PMID:19948161

Doi, Hirokazu; Horie, Toshiharu

2010-02-12

81

Inner ear deficits after chronic otitis media.  

PubMed

Investigation of the causes of vestibular symptoms in patients with chronic otitis media (COM) faces frustration, mainly because the bithermal caloric test using tap water is generally contraindicated in perforated ears. This study utilized audiometry, ocular vestibular-evoked myogenic potential (oVEMP) test, and cervical VEMP (cVEMP) test to evaluate inner ear deficits after COM. A total of 85 COM patients (117 ears) underwent otoscopy, image study, audiometry, oVEMP test, and cVEMP test. Mean bone-conducted (BC) hearing threshold ?25 dB was observed in 74 ears, 26-40 dB in 30 ears, and >40 dB in 13 ears. Restated, abnormal BC hearing threshold was identified in 43 ears (37 %). Percentages of abnormal cVEMP test, oVEMP test, and BC hearing threshold in 117 COM ears were 65, 62, and 37 %, respectively, exhibiting a significantly declining sequence in inner ear function. Furthermore, cVEMP/oVEMP test results were significantly correlated with BC hearing threshold, whereas no correlation existed between the cVEMP and oVEMP test results. In conclusion, the sequence of inner ear deficits after COM runs from the saccule/utricle to the cochlea and semicircular canals. Restated, in addition to BC hearing test, the cVEMP/oVEMP test may serve as a supplementary tool for early detection of inner ear involvement in COM patients. PMID:24061573

Chang, Chun-Wei; Cheng, Po-Wen; Young, Yi-Ho

2014-08-01

82

Alteration of arachidonate levels in tick salivary glands by dietary modification of host blood lipids.  

PubMed

Tick saliva contains prostaglandins of the 2-series, believed to facilitate bloodmeal acquisition. Because ticks cannot synthesize the prostaglandin precursor, arachidonic acid, investigations were undertaken to study the uptake, incorporation, and distribution of arachidonic acid in the salivary glands of the lone star tick in vitro and in vivo. Uptake of [3H]arachidonate by isolated salivary glands was reduced in the presence of low concentrations of arachidonic or eicosapentaenoic acids, but much higher, non-physiological concentrations of oleic and linoleic acids were required to inhibit [3H]arachidonate uptake. The incorporation of [3H]arachidonate into triglycerides increased at high concentrations of arachidonic or eicosapentaenoic acid, but not at any concentration of oleic or linoleic acid. Eicosatetraynoic acid greatly inhibited [3H]arachidonic acid. Guinea pigs fed hydrogenated coconut oil, safflower/primrose oil, or fish oil exhibited altered blood lipids; notably increased levels of eicosapentaenoic acid when fed fish oil. Salivary gland lipids in ticks fed on these hosts were also altered. Ticks parasitizing fish oil-fed guinea pigs contained high levels of eicosapentaenoic acid with a 30% reduction in arachidonate levels. The results demonstrated that eicosapentaenoic acid in the host diet had profound effects on arachidonate assimilation by tick salivary glands, which could lead to altered prostaglandin content in tick saliva. PMID:8541571

Madden, R D; Sauer, J R; Dillwith, J W; Bowman, A S

1996-01-01

83

Arachidonic acid closes gap junction channels in rat lacrimal glands  

Microsoft Academic Search

The effects of arachidonic acid (AA) on gap junction conductance of rat lacrimal glands have been studied with the double patch-clamp technique. Extracellular application of 50–100 µM AA for a few minutes induced a closure of gap junction channels. This effect was mimicked by linoleic acid and by other non-degradable fatty acids (myristic and lauric), and was not blocked by

Christian Giaume; Clotilde Randriamampita; Alain Trautmann

1989-01-01

84

Isolation of natural arachidonic acid as its methyl ester  

Microsoft Academic Search

Summary  Fresh beef suprarenal glands were ground and extracted thoroughly with alcohol and then with ethyl ether. After removal of\\u000a solvent the total lipid residue was saponified, and the fatty acids were recovered by extraction. The less unsaturated acids\\u000a were removed by crystallization from acetone at ?40C. At this stage the filtrate contained essentially all the arachidonic\\u000a acid originally present in

S. F. Herb; R. W. Riemenschneider; Jeanette Donaldson

1951-01-01

85

Influence of arachidonic acid metabolism on cell proliferation and apoptosis  

Microsoft Academic Search

\\u000a Research over the past three decades has revealed that arachidonic acid (AA) and oxygen-containing derivatives of AA, termed\\u000a eicosanoids, play pivotal roles in controlling key cellular events that lead to acute and chronic inflammation (for review,\\u000a see [1]). While it has been suggested for more than 50 years that diets high in certain fatty acids stimulate tumor development\\u000a in animals,

Floyd H. Chilton; Carl E. Clay; Anthony Trimboli; Alfred N. Fonteh

86

Arachidonic acid in aquaculture feeds: current status and future opportunities  

Microsoft Academic Search

The importance of arachidonic acid (20:4n?6, ARA) in fish nutrition has tended to be overlooked in preference to eicosapentaenoic (20:5n?3, EPA) and docosahexaenoic acids (22:6n?3, DHA), probably due to the predominance of the latter two HUFA in fish tissues. However, despite the abundance of EPA and DHA in fish tissues, the importance of ARA as the primary eicosanoid precursor has

J. Gordon Bell; John R. Sargent

2003-01-01

87

Arachidonic acid metabolites and sinonasal polyposis. I. Possible prognostic value  

Microsoft Academic Search

Purpose: The etiology of sinonasal polyps is sometimes obscure. This study was undertaken to evaluate the potential role of arachidonic acid metabolites (AAm) on recurrent polyposis.Materials and Methods: Tissue production of prostaglandin E2 (PGE2), 6-ketoprostaglandin F1-alpha (PGl2), thromboxane A2 (TxA2), and leukotriene C4 (LTC4) by nasal mucosa was determined by radioimmunoassay in 27 patients with sinonasal polyposis (SNp) and in

Ivica Klapan; Filip ?ulo; Josip ?ulig; Željka Bukovec; Stjepan Simovi?; ?uk Višeslav; Ranko Rišavi; Bumber Željko; Nikola Šprem; Vukoja Miljenko

1995-01-01

88

Lysophospholipid acyltransferases and arachidonate recycling in human neutrophils.  

PubMed

The cycle of deacylation and reacylation of phospholipids plays a critical role in regulating availability of arachidonic acid for eicosanoid production. The major yeast lysophospholipid acyltransferase, Ale1p, is related to mammalian membrane-bound O-acyltransferase (MBOAT) proteins. We expressed four human MBOATs in yeast strains lacking Ale1p and studied their acyl-CoA and lysophospholipid specificities using novel mass spectrometry-based enzyme assays. MBOAT1 is a lysophosphatidylserine (lyso-PS) acyltransferase with preference for oleoyl-CoA. MBOAT2 also prefers oleoyl-CoA, using lysophosphatidic acid and lysophosphatidylethanolamine as acyl acceptors. MBOAT5 prefers lysophosphatidylcholine and lyso-PS to incorporate linoleoyl and arachidonoyl chains. MBOAT7 is a lysophosphatidylinositol acyltransferase with remarkable specificity for arachidonoyl-CoA. MBOAT5 and MBOAT7 are particularly susceptible to inhibition by thimerosal. Human neutrophils express mRNA for these four enzymes, and neutrophil microsomes incorporate arachidonoyl chains into phosphatidylinositol, phosphatidylcholine, PS, and phosphatidylethanolamine in a thimerosal-sensitive manner. These results strongly implicate MBOAT5 and MBOAT7 in arachidonate recycling, thus regulating free arachidonic acid levels and leukotriene synthesis in neutrophils. PMID:18772128

Gijón, Miguel A; Riekhof, Wayne R; Zarini, Simona; Murphy, Robert C; Voelker, Dennis R

2008-10-31

89

Lysophospholipid Acyltransferases and Arachidonate Recycling in Human Neutrophils*  

PubMed Central

The cycle of deacylation and reacylation of phospholipids plays a critical role in regulating availability of arachidonic acid for eicosanoid production. The major yeast lysophospholipid acyltransferase, Ale1p, is related to mammalian membrane-bound O-acyltransferase (MBOAT) proteins. We expressed four human MBOATs in yeast strains lacking Ale1p and studied their acyl-CoA and lysophospholipid specificities using novel mass spectrometry-based enzyme assays. MBOAT1 is a lysophosphatidylserine (lyso-PS) acyltransferase with preference for oleoyl-CoA. MBOAT2 also prefers oleoyl-CoA, using lysophosphatidic acid and lysophosphatidylethanolamine as acyl acceptors. MBOAT5 prefers lysophosphatidylcholine and lyso-PS to incorporate linoleoyl and arachidonoyl chains. MBOAT7 is a lysophosphatidylinositol acyltransferase with remarkable specificity for arachidonoyl-CoA. MBOAT5 and MBOAT7 are particularly susceptible to inhibition by thimerosal. Human neutrophils express mRNA for these four enzymes, and neutrophil microsomes incorporate arachidonoyl chains into phosphatidylinositol, phosphatidylcholine, PS, and phosphatidylethanolamine in a thimerosal-sensitive manner. These results strongly implicate MBOAT5 and MBOAT7 in arachidonate recycling, thus regulating free arachidonic acid levels and leukotriene synthesis in neutrophils.

Gijon, Miguel A.; Riekhof, Wayne R.; Zarini, Simona; Murphy, Robert C.; Voelker, Dennis R.

2008-01-01

90

Kinetic study of the activation of the neutrophil NADPH oxidase by arachidonic acid. Antagonistic effects of arachidonic acid and phenylarsine oxide.  

PubMed

The O(2)(-) generating NADPH oxidase complex of neutrophils comprises two sets of components, namely a membrane-bound heterodimeric flavocytochrome b which contains the redox centers of the oxidase and water-soluble proteins of cytosolic origin which act as activating factors of the flavocytochrome. The NADPH oxidase can be activated in a cell-free system consisting of plasma membranes and cytosol from resting neutrophils in the presence of GTPgammaS and arachidonic acid. NADPH oxidase activation is inhibited by phenylarsine oxide (PAO), a sulfhydryl reagent for vicinal or proximal thiol groups. The site of action of PAO was localized by photolabeling in the beta-subunit of flavocytochrome b [Doussière, J., Poinas, A, Blais, C., and Vignais, P. V. (1998) Eur. J. Biochem. 251, 649-658]. Moreover, the spin state of heme b is controlled by interaction of arachidonic acid with the flavocytochrome b [Doussière, J., Gaillard, J., and Vignais, P. V. (1996) Biochemistry 35, 13400-13410]. Here we report that the promoting effect of arachidonic acid on the activation of NADPH oxidase is due to specific binding of arachidonic acid to flavocytochrome b. Elicitation of NADPH oxidase activity by arachidonic acid is in part associated with an increased affinity of flavocytochrome b for O(2), an effect that was counteracted by the methyl ester of arachidonic acid. On the other hand, the affinity for NADPH was not affected by arachidonic acid. We further demonstrate that PAO antagonizes the effect of arachidonic acid on oxidase activation by decreasing the affinity of the oxidase for O(2), but not for NADPH. PAO induced a change in the spin state of heme b, as arachidonic acid does, with, however, some differences in the constraints imposed to the heme. It is concluded that the opposite effects of arachidonic acid and PAO are exerted on the beta-subunit of flavocytochrome b at two different interacting sites. PMID:10587465

Doussiere, J; Bouzidi, F; Poinas, A; Gaillard, J; Vignais, P V

1999-12-01

91

21 CFR 874.4420 - Ear, nose, and throat manual surgical instrument.  

Code of Federal Regulations, 2010 CFR

...tonsil guillotine; tonsil screw; tonsil snare; tonsil suction tube; tonsil suturing...rongeur; nasal saw; nasal scissors; nasal snare; sinus irrigator; sinus trephine; ear...excavator; ear rasp; ear scissor, ear snare; ear spoon; ear suction tube;...

2009-04-01

92

21 CFR 874.4420 - Ear, nose, and throat manual surgical instrument.  

Code of Federal Regulations, 2010 CFR

...tonsil guillotine; tonsil screw; tonsil snare; tonsil suction tube; tonsil suturing...rongeur; nasal saw; nasal scissors; nasal snare; sinus irrigator; sinus trephine; ear...excavator; ear rasp; ear scissor, ear snare; ear spoon; ear suction tube;...

2010-04-01

93

Numerical simulation of the human ear and the dynamic analysis of the middle ear sound transmission  

NASA Astrophysics Data System (ADS)

Based on the clinical CT of normal right ear, a 3-D ?nite element (FE) model of the human ear consisting of the external ear canal, middle ear(tympanic membrane, ossicular chain, ligaments, tendons), and inner ear (including semicircular canals, vestibular, spiral cochlear)was constructed in this paper. The complicated structures and inner boundary conditions of middle ear were described in this model. Model analysis and acoustic-structure-?uid coupled dynamic frequency response analysis were conducted on the model. The validity of this model was confirmed by comparing the results with published experimental data. The amplitudes and velocities of tympanic membrane and stapes footplate, sound pressure gain across the middle ear, and the cochlear input impedance were derived. Besides, it was concluded that the ear canal can amplify the sound signal in low frequencies.The modes of vibration of middle ear auditory ossicles, oval window and round window have been analysed. This model can well simulate the acoustic behavior with the interaction of external ear, middle ear and inner ear, which can supply more valuable theoretical support for development and improvement of hearing-aid and artificial inner ear.

Yao, W.; Ma, J.; Huang, X.

2013-06-01

94

Dual pathways for carbamylcholine-stimulated arachidonic acid release in rat pancreatic acini  

Microsoft Academic Search

Recent studies suggested the involvement of arachidonic acid in the mediation of pancreatic amylase release. However, an effect\\u000a of carbamylcholine on arachidonic acid release has not yet been reported in the exocrine pancreas. This study was performed\\u000a to evaluate the effect of carbamylcholine on arachidonic acid release and determine the underlying intracellular mechanisms.\\u000a From enzymatic assays, phospholipase A2 and diacylglycerol

Wei Hou; Yoshiyuki Arita; Jean Morisset

1996-01-01

95

Regulation of Arachidonic Acid Release by Calcium Influx in Human Endothelial Cells  

Microsoft Academic Search

In response to stimuli, endothelial cells release arachidonic acid, a lipid precursor of various vasoactive substances. We have investigated the relationships between cytosolic Ca2+ movements and arachidonic acid release in human umbilical vein endothelial cells. Histamine, a receptor-dependent agonist, and thapsigargin, a specific inhibitor of sarco-\\/endoplasmic Ca2+ pumps, time- and dose-dependently increased the release of [1-14C]-arachidonic acid. This release was

Elisabeth Millanvoye-Van Brussel; Monique David-Dufilho; Thuc Do Pham; Lahcen Iouzalen; Marie Aude Devynck

1999-01-01

96

Attachment of substrate metabolite to prostaglandin H synthase upon reaction with arachidonic acid  

SciTech Connect

Prostaglandin H synthase was incubated with (/sup 14/C)arachidonate and then analyzed by polyacrylamide gel electrophoresis under denaturing conditions and by high pressure liquid chromatography. A maximum of 1 mol of arachidonate metabolite was found to become attached per mol of synthase subunit in a time-dependent process that was much slower than the rate of self-catalyzed inactivation of the cyclooxygenase activity. Incubation of a mixture of the synthase and ovalbumin with (/sup 14/C)arachidonate resulted in a selective attachment of radiolabel to the synthase. These results suggest the presence of a single site on the synthase that is susceptible to reaction with an arachidonate metabolite.

Kulmacz, R.J.

1987-10-29

97

Molecular Mechanisms of Inner Ear Development  

PubMed Central

The inner ear is a structurally complex vertebrate organ built to encode sound, motion, and orientation in space. Given its complexity, it is not surprising that inner ear dysfunction is a relatively common consequence of human genetic mutation. Studies in model organisms suggest that many genes currently known to be associated with human hearing impairment are active during embryogenesis. Hence, the study of inner ear development provides a rich context for understanding the functions of genes implicated in hearing loss. This chapter focuses on molecular mechanisms of inner ear development derived from studies of model organisms.

Wu, Doris K.; Kelley, Matthew W.

2012-01-01

98

Could ionizing radiation forestall cauliflower ear?  

PubMed

Repeated trauma to the ear very often results in "cauliflower ear." Many methods have been suggested to prevent an injured ear from demonstrating a cauliflowerlike deformity. The principles of treatment are evacuation of the hematoma, control of the reaccumulation of fluid, and maintenance of the cartilage contour. The authors studied the effect of ionizing radiation on deformed rabbit ears induced by repeated trauma. Twenty ears (10 rabbits) were used in the experiment. The animals were divided into four groups (control, preradiation, low dose, and high dose). Hematoma was produced by pounding the lateral side of the auricle 10 times with a 50-g weight at a height of 15 cm. The thickness of the injured and uninjured sites was measured, and histological analysis was performed for each group. The thickness of the ears of the irradiated groups was significantly less than the control group. The authors think that radiation treatment of repeatedly injured ears could prevent ear deformity, and could possibly be an adjunctive form of management of cauliflower ear in addition to hematoma evacuation and compression therapy. PMID:11216608

Hwang, K; Kim, C W; Lee, S I; Park, I S; Kim, W C; Loh, J J

2001-02-01

99

Cerebral Arachidonate Cascade in Dementia: Alzheimer's Disease and Vascular Dementia  

PubMed Central

Phospholipase A2 (PLA2), cyclooxygenase (COX) and prostaglandin (PG) synthase are enzymes involved in arachidonate cascade. PLA2 liberates arachidonic acid (AA) from cell membrane lipids. COX oxidizes AA to PGG2 followed by an endoperoxidase reaction that converts PGG2 into PGH2. PGs are generated from astrocytes, microglial cells and neurons in the central nervous system, and are altered in the brain of demented patients. Dementia is principally diagnosed into Alzheimer’s disease (AD) and vascular dementia (VaD). In older patients, the brain lesions associated with each pathological process often occur together. Regional brain microvascular abnormalities appear before cognitive decline and neurodegeneration. The coexistence of AD and VaD pathology is often termed mixed dementia. AD and VaD brain lesions interact in important ways to decline cognition, suggesting common pathways of the two neurological diseases. Arachidonate cascade is one of the converged intracellular signal transductions between AD and VaD. PLA2 from mammalian sources are classified as secreted (sPLA2), Ca2+-dependent, cytosolic (cPLA2) and Ca2+-independent cytosolic PLA2 (iPLA2). PLA2 activity can be regulated by calcium, by phosphorylation, and by agonists binding to G-protein-coupled receptors. cPLA2 is upregulalted in AD, but iPLA2 is downregulated. On the other hand, sPLA2 is increased in animal models for VaD. COX-2 is induced and PGD2 are elevated in both AD and VaD. This review presents evidences for central roles of PLA2s, COXs and PGs in the dementia.

Yagami, Tatsurou

2006-01-01

100

Modulation of arachidonic acid metabolism by Rous sarcoma virus  

SciTech Connect

Arachidonic acid (C{sub 20:4}) metabolites were released constitutively from wild-type Rous sarcoma virus-transformed chicken embryo fibroblasts (CEF). {sup 3}H-labeled C{sub 20:4} and its metabolites were released from unstimulated and uninfected CEF only in response to stimuli such as serum, phorbol ester, or the calcium ionophore A23187. High-pressure liquid chromatography analysis showed that the radioactivity released from ({sup 3}H)arachidonate-labeled transformed cells was contained in free arachidonate and in the cyclooxygenase products prostaglandin E{sub 2} and prostaglandin F{sub 2} alpha; no lipoxygenase products were identified. The release of C{sub 20:4} and its metabolites from CEF infected with pp60{sup src} deletion mutants was correlated with serum-independent DNA synthesis and with the expression of the mRNA for 9E3, a gene expressed in Rous sarcoma virus-transformed cells which has homology with several mitogenic and inflammatory peptides. {sup 3}H-labeled C{sub 20:4} release was not correlated with p36 phosphorylation, which argues against a role for this protein as a phospholipase A{sub 2} inhibitor. CEF infected with other oncogenic viruses encoding a tyrosine kinase also released C{sub 20:4}, as did CEF infected with viruses that contained mos and ras; however, infection with a crk-containing virus did not result in stimulation of {sup 3}H-labeled C{sub 20:4} release, suggesting that utilization of this signaling pathway is specific for particular transformation stimuli.

Barker, K.; Aderem, A.; Hanafusa, H. (Rockefeller Univ., New York, NY (USA))

1989-07-01

101

Phospholipase A2 and Arachidonic Acid in Alzheimer's Disease  

PubMed Central

Essential fatty acids (EFA) play a critical role in the brain and regulate many of the processes altered in Alzheimer’s disease (AD). Technical advances are allowing for the dissection of complex lipid pathways in normal and diseased states. Arachidonic acid (AA) and specific isoforms of phospholipase A2 (PLA2) appear to play critical mediator roles in amyloid-? (A?) - induced pathogenesis, leading to learning, memory, and behavioral impairments in mouse models of AD. These findings and ongoing research into lipid biology in AD and related disorders promise to reveal new pharmacological targets that may lead to better treatments for these devastating conditions.

Sanchez-Mejia, Rene O.; Mucke, Lennart

2011-01-01

102

Differential metabolism of exogenous and endogenous arachidonic acid in human neutrophils.  

PubMed

Leukotrienes can be produced by cooperative interactions between cells in which, for example, arachidonate derived from one cell is oxidized to leukotriene A(4) (LTA(4)) by another and this can then be exported for conversion to LTB(4) or cysteinyl leukotrienes (cys-LTs) by yet another. Neutrophils do not contain LTC(4) synthase but are known to cooperate with endothelial cells or platelets (which do have this enzyme) to generate cys-LTs. Stimulation of human neutrophils perfusing isolated rabbit hearts resulted in production of cys-LTs, whereas these were not seen with perfused hearts alone or isolated neutrophils. In addition, the stimulated, neutrophil-perfused hearts generated much greater amounts of total LTA(4) products, suggesting that the hearts were supplying arachidonate to the neutrophils and, in addition, that this externally derived arachidonate was preferentially used for exported LTA(4) that could be metabolized to cys-LTs by the coronary endothelium. Stable isotope-labeled arachidonate and electrospray tandem mass spectrometry were used to differentially follow metabolism of exogenous and endogenous arachidonate. Isolated, adherent neutrophils at low concentrations (to minimize transcellular metabolism between them) were shown to generate higher proportions of nonenzymatic LTA(4) products from exogenous arachidonate (deuterium-labeled) than from endogenous (unlabeled) sources. The endogenous arachidonate, on the other hand, was preferentially used for conversion to LTB(4) by the LTA(4) hydrolase. This result was not because of saturation of the LTA(4) hydrolase, because it occurred at widely differing concentrations of exogenous arachidonate. Finally, in the presence of platelets (which contain LTC(4) synthase), the LTA(4) synthesized from exogenous deuterium-labeled arachidonate was converted to cys-LTs to a greater degree than that from endogenous sources. These experiments suggest that exogenous arachidonate is preferentially converted to LTA(4) for export (not intracellular conversion) and raises the likelihood that there are different intracellular pathways for arachidonate metabolism. PMID:10497182

Sala, A; Zarini, S; Folco, G; Murphy, R C; Henson, P M

1999-10-01

103

Increased isoprostane levels in oleic acid-induced lung injury  

SciTech Connect

The present study was performed to examine a role of oxidative stress in oleic acid-induced lung injury model. Fifteen anesthetized sheep were ventilated and instrumented with a lung lymph fistula and vascular catheters for blood gas analysis and measurement of isoprostanes (8-epi prostaglandin F2{alpha}). Following stable baseline measurements, oleic acid (0.08 ml/kg) was administered and observed 4 h. Isoprostane was measured by gas chromatography mass spectrometry with the isotope dilution method. Isoprostane levels in plasma and lung lymph were significantly increased 2 h after oleic acid administration and then decreased at 4 h. The percent increases in isoprostane levels in plasma and lung lymph at 2 h were significantly correlated with deteriorated oxygenation at the same time point, respectively. These findings suggest that oxidative stress is involved in the pathogenesis of the pulmonary fat embolism-induced acute lung injury model in sheep and that the increase relates with the deteriorated oxygenation.

Ono, Koichi [Department of Anesthesiology and Resuscitation, Shinshu University School of Medicine, Matsumoto (Japan)] [Department of Anesthesiology and Resuscitation, Shinshu University School of Medicine, Matsumoto (Japan); Koizumi, Tomonobu, E-mail: tomonobu@shinshu-u.ac.jp [First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto (Japan)] [First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto (Japan); Tsushima, Kenji; Yoshikawa, Sumiko; Yokoyama, Toshiki [First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto (Japan)] [First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto (Japan); Nakagawa, Rikimaru [Department of Anesthesiology and Resuscitation, Shinshu University School of Medicine, Matsumoto (Japan)] [Department of Anesthesiology and Resuscitation, Shinshu University School of Medicine, Matsumoto (Japan); Obata, Toru [Department of Molecular Cell Biology, Institute of DNA Medicine, Jikei University School of Medicine, Tokyo (Japan)] [Department of Molecular Cell Biology, Institute of DNA Medicine, Jikei University School of Medicine, Tokyo (Japan)

2009-10-16

104

INNER EAR EMBRYOGENESIS: GENETIC AND ENVIRONMENTAL DETERMINANTS  

EPA Science Inventory

The anatomy and developmental molecular genetics of the inner ear from establishment of the otic placode to formation of the definitive cochlea and vestibular apparatus will be reviewed and the complex 3-D structural changes that shape the developing inner ear will be illustrated...

105

Ear piercing for individuals with metal hypersensitivity  

Microsoft Academic Search

Objective: To describe and evaluate an ear piercing and earring retention method for individuals with metal hypersensitivity. Setting: Private facial plastic surgery practice associated with a tertiary care medical center. Methods: Thirty-one patients with a history of hypersensitivity to metallic jewelry (62 ears) underwent earlobe piercing with an intravenous catheter. Results: None of the patients experienced an infection or hypersensitivity

Anthony J. Cornetta; David Reiter

2001-01-01

106

Middle ear malformations in identical twins.  

PubMed

The majority of the congenital anomalies of middle ear are solitary and a non-hereditary. We report cases of identical twins with congenital incudo-stapedial disconnection. Case 1 was an 8-year-old girl. Hearing impairment was identified at the age of three. She was referred to our university hospital in April 2005. Pure-tone audiogram showed conductive hearing impairments. Computed tomography (CT) revealed the incudo-stapedial disconnections in both ears. The exploratory tympanotomies on the right and left ears were performed in May and July 2005, respectively. The surgical findings showed absence of the long process and presence of the lenticular process of the incus in both ears. After the reconstructions of ossicular chain, the hearing of both ears improved. Case 2 was an 11-year-old girl. The hearing impairment of the right ear was identified in May 2008. She was referred to our university hospital three months later. Pure-tone audiogram showed the conductive hearing impairment in the right ear. CT revealed the incudo-stapedial disconnection in the right ear. The surgery showed the same findings as those of case 1. Anomalies of both cases suggest that the lenticular process of the incus and the stapes originate from a common primordium. PMID:24355584

Kidowaki, Naoko; Kamitani, Toru; Nakamura, Takashi; Taki, Masakatsu; Sakaguchi, Hirofumi; Suzuki, Toshihiro; Hisa, Yasuo

2014-06-01

107

Inner ear drug delivery for auditory applications  

Microsoft Academic Search

Many inner ear disorders cannot be adequately treated by systemic drug delivery. A blood-cochlear barrier exists, similar physiologically to the blood-brain barrier, which limits the concentration and size of molecules able to leave the circulation and gain access to the cells of the inner ear. However, research in novel therapeutics and delivery systems has led to significant progress in the

Erin E. Leary Swan; Mark J. Mescher; William F. Sewell; Sarah L. Tao; Jeffrey T. Borenstein

2008-01-01

108

Hemangioma as Mass of External Ear Canal  

Microsoft Academic Search

Patient with a round and soft lesion completely covered with skin without modification in color fulfilling approximately 90% of external ear canal diameter. Patient’s complain was dullness sensations on affected ear. CT scan demonstrated lack of tympanic membrane commitment and pathological findings were compatible with hemangioma. Conclusion: It is important to define whether there is hemangioma's involvement of tympanic membrane,

José Faibes Lubianca Neto; Mauricio Schreiner Miura; Catia Saleh; Marina de Andrade; Melina Assmann

109

"Hot Tub Rash" and "Swimmer's Ear" (Pseudomonas)  

MedlinePLUS

Facts About “Hot Tub Rash” and “Swimmer’s Ear” (Pseudomonas) What is Pseudomonas and how can it affect me? Pseudomonas (sue-doh- ... a major cause of infections commonly known as “hot tub rash” and “swimmer’s ear.” This germ is ...

110

Arachidonic Acid and Prostaglandins Enhance Potassium-Stimulated Calcium InFlux into Rat Brain Synaptosomes.  

National Technical Information Service (NTIS)

Exogenous administration of arachidonic acid, prostaglandins PGF2 alpha, PGD2 and PGE2 increased potassium-stimulated uptake of calcium in rat brain synaptosomes from the brain of the rat, but had no effect on the basal uptake of calcium. Arachidonic acid...

S. B. Kandasamy W. A. Hunt

1990-01-01

111

Generation of a chemotactic lipid from arachidonic acid by exposure to a superoxide-generating system  

Microsoft Academic Search

Certain products of arachidonic acid have been demonstrated recently to possess chemotactic activity for human polymorphonuclear leukocytes (PMN). Enzymatic (lipoxygenase, cyclooxygenase) generation of these lipid chemotaxins proceeds through the formation of intermediate lipid peroxides. Since lipid peroxidation can be mediated by oxygen-derived free radicals, we have examined whether chemotactically active products of arachidonic acid could be produced by exposing this

H. Daniel Perez; Babette B. Weksler; Ira M. Goldstein

1980-01-01

112

Utilization of arachidonic and linoleic acids by cultured human endothelial cells.  

PubMed Central

When cultured human umbilical vein endothelial cells are supplemented with linoleic acid, the arachidonic acid content of the cellular phospholipids is reduced approximately 35%. Most of the fatty acid compositional change occurs during the first 24 h. One factor responsible for this effect is the inability of the endothelial cells to convert appreciable amounts of linoleic to arachidonic acid, due to a fatty acid delta 6-desaturase deficiency. By contrast, these endothelial cultures contain delta 5- and delta 9-desaturase activity and are able to elongate long-chain polyunsaturated fatty acids. The other factor that contributes to the decrease in arachidonic acid is that high concentrations of linoleic acid reduce the incorporation of arachidonate into cellular phospholipids. Stearic acid, a long-chain saturate, does not produce any reduction, whereas eicosatrienoic acid is an even more effective inhibitor than linoleic acid. In spite of the fact that high concentrations of these polyunsaturates produced inhibition, the endothelial cells were found to efficiently incorporate exogenous arachidonic acid into cellular phospholipids and triglycerides. This may serve to compensate for the inability of these cells to synthesize arachidonic acid from linoleic acid. These findings suggest that the endothelium obtains arachidonic acid from an extracellular source, that this cannot be provided in the form of linoleic acid and, in fact, that high concentrations of linoleic acid actually may interfere with the ability of the endothelium to maintain an adequate supply of intracellular arachidonic acid.

Spector, A A; Kaduce, T L; Hoak, J C; Fry, G L

1981-01-01

113

Arachidonic Acid Is Preferentially Metabolized by Cyclooxygenase2 to Prostacyclin and Prostaglandin E2  

Microsoft Academic Search

The two cyclooxygenase isoforms, cyclooxygenase-1 and cyclooxygenase-2, both metabolize arachidonic acid to prostaglandin H2, which is subsequently processed by downstream enzymes to the various prostanoids. In the present study, we asked if the two isoforms differ in the profile of prostanoids that ultimately arise from their action on arachidonic acid. Resident peritoneal macro- phages contained only cyclooxygenase-1 and synthe- sized

Thomas G. Brock; Robert W. McNish; Marc Peters-Golden

1999-01-01

114

Arachidonic acid enhances turnover of the dermal skeleton: studies on zebrafish scales.  

PubMed

In fish nutrition, the ratio between omega-3 and omega-6 poly-unsaturated fatty acids influences skeletal development. Supplementation of fish oils with vegetable oils increases the content of omega-6 fatty acids, such as arachidonic acid in the diet. Arachidonic acid is metabolized by cyclooxygenases to prostaglandin E2, an eicosanoid with effects on bone formation and remodeling. To elucidate effects of poly-unsaturated fatty acids on developing and existing skeletal tissues, zebrafish (Danio rerio) were fed (micro-) diets low and high in arachidonic acid content. Elasmoid scales, dermal skeletal plates, are ideal to study skeletal metabolism in zebrafish and were exploited in the present study. The fatty acid profile resulting from a high arachidonic acid diet induced mild but significant increase in matrix resorption in ontogenetic scales of adult zebrafish. Arachidonic acid affected scale regeneration (following removal of ontogenetic scales): mineral deposition was altered and both gene expression and enzymatic matrix metalloproteinase activity changed towards enhanced osteoclastic activity. Arachidonic acid also clearly stimulates matrix metalloproteinase activity in vitro, which implies that resorptive effects of arachidonic acid are mediated by matrix metalloproteinases. The gene expression profile further suggests that arachidonic acid increases maturation rate of the regenerating scale; in other words, enhances turnover. The zebrafish scale is an excellent model to study how and which fatty acids affect skeletal formation. PMID:24586706

de Vrieze, Erik; Moren, Mari; Metz, Juriaan R; Flik, Gert; Lie, Kai Kristoffer

2014-01-01

115

Gene therapy for the inner ear  

PubMed Central

Animal studies on inner ear development, repair and regeneration provide understanding of molecular pathways that can be harnessed for treating inner ear disease. Use of transgenic mouse technology, in particular, has contributed knowledge of genes that regulate development of hair cells and innervation, and of molecular players that can induce regeneration, but this technology is not applicable for human treatment, for practical and ethical reasons. Therefore other means for influencing gene expression in the inner ear are needed. We describe several gene vectors useful for inner ear gene therapy and the practical aspects of introducing these vectors into the ear. We then review the progress toward using gene transfer for therapies in both auditory and balance systems, and discuss the technological milestones needed to advance to clinical application of these methods.

Fukui, Hideto; Raphael, Yehoash

2012-01-01

116

Biometric recognition using 3D ear shape.  

PubMed

Previous works have shown that the ear is a promising candidate for biometric identification. However, in prior work, the preprocessing of ear images has had manual steps and algorithms have not necessarily handled problems caused by hair and earrings. We present a complete system for ear biometrics, including automated segmentation of the ear in a profile view image and 3D shape matching for recognition. We evaluated this system with the largest experimental study to date in ear biometrics, achieving a rank-one recognition rate of 97.8 percent for an identification scenario and an equal error rate of 1.2 percent for a verification scenario on a database of 415 subjects and 1,386 total probes. PMID:17568136

Yan, Ping; Bowyer, Kevin W

2007-08-01

117

Perspective methods of human identification: Ear biometrics  

NASA Astrophysics Data System (ADS)

Geometrical methods of feature extraction from ear images in order to perform human identification are presented. Geometrical approach is motivated by the actual procedures used by police and forensic experts (so-called ear otoscopy). In their work, geometrical features of ears such as size, height, width, and shapes of earlobe are useful and valid proofs of identity. The contribution of the article is development of the new and original methods of geometrical feature extraction from 2D ear images. Four novel algorithms of ear feature extraction from contour images are described in detail. Moreover, identification results obtained for each of the methods, based on the distance of feature vectors in the feature space, are presented.

Chora?, M.

2008-03-01

118

Oxygenation products of arachidonic acid: third messengers for insulin release.  

PubMed

Although an association between membrane phospholipid turnover and exocytotic hormone release has long been recognized, a causal relationship has not been firmly established. Recent studies suggest that glucose (and probably other insulin secretagogues) activates phospholipases and thereby releases membrane-bound arachidonic acid (AA). AA is then converted through islet 12-lipoxygenase to mediators or modulators of insulin release (tentatively identified as peroxides and epoxides of arachidonate). These products may be critical links in stimulus-secretion coupling, since blockade of either AA release or lipoxygenation abrogates insulin release induced by glucose and many other (but not all) stimuli. Cogeneration of prostaglandins from AA through the cyclooxygenase pathway may directly or indirectly modulate the formation and/or effect of lipoxygenase products. A critical role for lipoxygenase products (and possibly metabolites of AA synthesized by other pathways, such as P-450-dependent monooxygenases) may extend to many secretory cells in addition to pancreatic beta cells. The phasic release of AA described in many cells could explain the biphasic pattern of insulin release induced by glucose. Since some phospholipases and lipoxygenases are Ca++ activated, the release of AA in conjunction with its oxygenation appears to be a concerted system generating "third messengers" for hormone release. PMID:6432880

Metz, S A; Fujimoto, W Y; Robertson, R P

1984-09-01

119

Docosahexaenoic acid and other fatty acids induce a decrease in pHi in Jurkat T-cells  

PubMed Central

Docosahexaenoic acid (DHA) induced rapid (t1/2=33 s) and dose-dependent decreases in pHi in BCECF-loaded human (Jurkat) T-cells. Addition of 5-(N,N-dimethyl)-amiloride, an inhibitor of Na+/H+ exchanger, prolonged DHA-induced acidification as a function of time, indicating that the exchanger is implicated in pHi recovery. Other fatty acids like oleic acid, arachidonic acid, eicosapentaenoic acid, but not palmitic acid, also induced a fall in pHi in these cells. To assess the role of calcium in the DHA-induced acidification, we conducted experiments in Ca2+-free (0% Ca2+) and Ca2+-containing (100% Ca2+) buffer. We observed that there was no difference in the degree of DHA-induced transient acidification in both the experimental conditions, though pHi recovery was faster in 0% Ca2+ medium than that in 100% Ca2+ medium. In the presence of BAPTA, a calcium chelator, a rapid recovery of DHA-induced acidosis was observed. Furthermore, addition of CaCl2 into 0% Ca2+ medium curtailed DHA-evoked rapid pHi recovery. In 0% Ca2+ medium, containing BAPTA, DHA did not evoke increases in [Ca2+]i, though this fatty acid still induced a rapid acidification in these cells. These observations suggest that calcium is implicated in the long-lasting DHA-induced acidosis. DHA-induced rapid acidification may be due to its deprotonation in the plasma membrane (flip-flop model), as suggested by the following observations: (1) DHA with a –COOH group induced intracellular acidification, but this fatty acid with a –COOCH3 group failed to do so, and (2) DHA, but not propionic acid, -induced acidification was completely reversed by addition of fatty acid-free bovine serum albumin in these cells. These results suggest that DHA induces acidosis via deprotonation and Ca2+ mobilization in human T-cells.

Aires, Virginie; Hichami, Aziz; Moutairou, Kabirou; Khan, Naim Akhtar

2003-01-01

120

Activation of human immunodeficiency virus long terminal repeat by arachidonic acid.  

PubMed

Arachidonic acid is the precursor of highly reactive mediators, including prostaglandins and leukotrienes, and the most abundant n-6 polyunsaturated fatty acid in mammalian cell membranes. It is released from phospholipids upon many inflammatory stimuli. In this study, a chloramphenicol acyltransferase reporter gene, under control of the human immunodeficiency virus-1 long terminal repeat, was strongly induced upon treating human promonocytes with arachidonic acid. The n-3 fatty acid eicosapentenoic, found in abundance in fish oil, had no effect. HIV-1 long terminal repeat activation by arachidonic acid was suppressed by inhibitors of both lipoxygenase and cyclooxygenase pathways, suggesting that metabolites, rather than arachidonic acid itself, mediated the stimulatory effect. This is the first report linking HIV-1 expression to the metabolism of arachidonic acid. PMID:8958144

Carini, R; Leonarduzzi, G; Camandola, S; Musso, T; Varesio, L; Baeuerle, P A; Poli, G

1997-01-01

121

Earth Sciences: Instrumentation and Facilities (EAR/IF)  

NSF Publications Database

Earth Sciences: Instrumentation and Facilities (EAR/IF) Program Solicitation NSF 04-507 Replaces ... of Earth Sciences (EAR) supports research and education focused on understanding Earth dynamics ...

122

Numerical analysis of ossicular chain lesion of human ear  

NASA Astrophysics Data System (ADS)

Lesion of ossicular chain is a common ear disease impairing the sense of hearing. A comprehensive numerical model of human ear can provide better understanding of sound transmission. In this study, we propose a three-dimensional finite element model of human ear that incorporates the canal, tympanic membrane, ossicular bones, middle ear suspensory ligaments/muscles, middle ear cavity and inner ear fluid. Numerical analysis is conducted and employed to predict the effects of middle ear cavity, malleus handle defect, hypoplasia of the long process of incus, and stapedial crus defect on sound transmission. The present finite element model is shown to be reasonable in predicting the ossicular mechanics of human ear.

Liu, Yingxi; Li, Sheng; Sun, Xiuzhen

2009-04-01

123

Assessment of skin absorption and irritation potential of arachidonic acid and glyceryl arachidonate using in vitro diffusion cell techniques.  

PubMed

Arachidonic acid (AA), a precursor of pro-inflammatory mediators, and its glycerin ester, glyceryl arachidonate (GA), are reportedly used in cosmetic products. In vitro skin penetration of AA and GA and GA's ester hydrolysis was determined in flow-through diffusion cells. AA penetration with human and rat skin was 19.5% and 52.3% of the applied dose respectively, a substantial amount of which remained in the skin at 24h. Similar penetration results were obtained with GA in human skin. However, GA penetration through cultured skin (EpiDerm) was 51% of the applied dose, almost all of which appeared in the receptor fluid. At least 27.8% of GA penetrating skin was hydrolyzed to AA. In vitro methods were used to assess skin irritation in diffusion cells. Skin irritation of AA, sodium lauryl sulfate (SLS), and Tween 80 was determined by changes in transepidermal water loss (TEWL), skin viability (3-(4,5-dimethylthiaxol-2-yl)-2,5-diphenyltetrazolium bromide, MTT, formation), and cytokine release (IL-1alpha). SLS irritation was much less pronounced in an emulsion versus an aqueous vehicle. No significant irritation was observed in vitro from AA in an emulsion. This work predicts that AA would penetrate human skin in vivo and that it could be formed in skin from topically applied GA. PMID:17602815

Eppler, A R; Kraeling, M E K; Wickett, R R; Bronaugh, R L

2007-11-01

124

Tuberculous Disease of the Middle Ear  

PubMed Central

History.—Primary and secondary types.—Incidence in (a) Phthisical patients, (b) Patients with suppurating ears, (c) Children.—Modes of infection: (a) by Eustachian tube, (b) by blood-stream.—Signs and symptoms: Painless onset; Early appearances of middle-ear; Infiltration of tympanic membrane; Multiple perforation; Granulation tissue; Type of discharge.—Examination of discharge and of granulation tissue.—Course of disease in middle-ear; Extensions; Complications.—Special types: Mastoiditis in children; Tumour formation.—Deafness.—Reports of twenty cases.

Ormerod, F. C.

1931-01-01

125

Hearing: How Do Our Ears Work?  

NSDL National Science Digital Library

Students learn about the anatomy of the ear and how the ears work as a sound sensor. Ear anatomy parts and structures are explained in detail, as well as how sound is transmitted mechanically and then electrically through them to the brain. Students use LEGO® robots with sound sensors to measure sound intensities, learning how the NXT brick (computer) converts the intensity of sound measured by the sensor input into a number that transmits to a screen. They build on their experiences from the previous activities and establish a rich understanding of the sound sensor and its relationship to the TaskBot's computer.

GK-12 Program, Computational Neurobiology Center, College of Engineering,

126

Computerized image analysis for acetic acid induced intraepithelial lesions  

NASA Astrophysics Data System (ADS)

Cervical Intraepithelial Neoplasia (CIN) exhibits certain morphologic features that can be identified during a visual inspection exam. Immature and dysphasic cervical squamous epithelium turns white after application of acetic acid during the exam. The whitening process occurs visually over several minutes and subjectively discriminates between dysphasic and normal tissue. Digital imaging technologies allow us to assist the physician analyzing the acetic acid induced lesions (acetowhite region) in a fully automatic way. This paper reports a study designed to measure multiple parameters of the acetowhitening process from two images captured with a digital colposcope. One image is captured before the acetic acid application, and the other is captured after the acetic acid application. The spatial change of the acetowhitening is extracted using color and texture information in the post acetic acid image; the temporal change is extracted from the intensity and color changes between the post acetic acid and pre acetic acid images with an automatic alignment. The imaging and data analysis system has been evaluated with a total of 99 human subjects and demonstrate its potential to screening underserved women where access to skilled colposcopists is limited.

Li, Wenjing; Ferris, Daron G.; Lieberman, Rich W.

2008-04-01

127

Metformin Protects Rat Hepatocytes against Bile Acid-Induced Apoptosis  

PubMed Central

Background Metformin is used in the treatment of Diabetes Mellitus type II and improves liver function in patients with non-alcoholic fatty liver disease (NAFLD). Metformin activates AMP-activated protein kinase (AMPK), the cellular energy sensor that is sensitive to changes in the AMP/ATP-ratio. AMPK is an inhibitor of mammalian target of rapamycin (mTOR). Both AMPK and mTOR are able to modulate cell death. Aim To evaluate the effects of metformin on hepatocyte cell death. Methods Apoptotic cell death was induced in primary rat hepatocytes using either the bile acid glycochenodeoxycholic acid (GCDCA) or TNF? in combination with actinomycin D (actD). AMPK, mTOR and phosphoinositide-3 kinase (PI3K)/Akt were inhibited using pharmacological inhibitors. Apoptosis and necrosis were quantified by caspase activation, acridine orange staining and Sytox green staining respectively. Results Metformin dose-dependently reduces GCDCA-induced apoptosis, even when added 2 hours after GCDCA, without increasing necrotic cell death. Metformin does not protect against TNF?/ActD-induced apoptosis. The protective effect of metformin is dependent on an intact PI3-kinase/Akt pathway, but does not require AMPK/mTOR-signaling. Metformin does not inhibit NF-?B activation. Conclusion Metformin protects against bile acid-induced apoptosis and could be considered in the treatment of chronic liver diseases accompanied by inflammation.

Woudenberg-Vrenken, Titia E.; Conde de la Rosa, Laura; Buist-Homan, Manon; Faber, Klaas Nico; Moshage, Han

2013-01-01

128

Nucleic acid-induced antiviral immunity in shrimp.  

PubMed

Vertebrates detect viral infection predominantly by sensing viral nucleic acids to produce type I interferon (IFN). In invertebrates, it has been believed that the IFN system is absent and RNA interference is a sequence-specific antiviral pathway. In this study, we found that injection of nucleic acid mimics poly(I:C), poly(C:G), CL097, poly C and CpG-DNA, afforded shrimp antiviral immunity, which is similar to the vertebrate IFN system. Using suppression subtractive hybridization (SSH) method, 480 expression sequence tags were identified to be involved in the poly(I:C)-induced antiviral immunity of the model crustacean Litopenaeus vannamei, and 41% of them were new genes. In the SSH libraries, several IFN system-related genes such as dsRNA-dependent protein kinase PKR, Toll-like receptor 3 (TLR3) and IFN?-inducible protein 30 were identified. L. vannamei IKK?, whose vertebrate homologs are central regulators of the IFN-producing pathway, could significantly activate IFN reporter genes in HEK293T cells. In crustacean databases, many genes homologous to genes of the vertebrate IFN response, such as IRFs, PKR, ADAR (adenosine deaminase, RNA-specific) and other interferon-stimulated genes (ISGs) were discovered. These results suggest that shrimp may possess nucleic acid-induced antiviral immunity. PMID:23773856

Wang, Pei-Hui; Yang, Li-Shi; Gu, Zhi-Hua; Weng, Shao-Ping; Yu, Xiao-Qiang; He, Jian-Guo

2013-09-01

129

An analysis of the acoustic input impedance of the ear.  

PubMed

Ear canal acoustics was examined using a one-dimensional lossy transmission line with a distributed load impedance to model the ear. The acoustic input impedance of the ear was derived from sound pressure measurements in the ear canal of healthy human ears. A nonlinear least squares fit of the model to data generated estimates for ear canal radius, ear canal length, and quantified the resistance that would produce transmission losses. Derivation of ear canal radius has application to quantifying the impedance mismatch at the eardrum between the ear canal and the middle ear. The length of the ear canal was found, in general, to be longer than the length derived from the one-quarter wavelength standing wave frequency, consistent with the middle ear being mass-controlled at the standing wave frequency. Viscothermal losses in the ear canal, in some cases, may exceed that attributable to a smooth rigid wall. Resistance in the middle ear was found to contribute significantly to the total resistance. In effect, this analysis "reverse engineers" physical parameters of the ear from sound pressure measurements in the ear canal. PMID:23917695

Withnell, Robert H; Gowdy, Lauren E

2013-10-01

130

Middle Ear Adenoma: Case Report and Discussion  

PubMed Central

Introduction. Despite modern radiological workup, surgeons can still be surprised by intraoperative findings or by the pathologist's report. Materials & Methods. We describe the case of a 52-year-old male who was referred to our clinic with a single sided conductive hearing loss. He ultimately underwent middle ear exploration and excision of a middle ear tumour followed by second look and ossiculoplasty a year later. Results. Though preoperative CT and MRI scanning were suggestive of a congenital cholesteatoma, the pathologist's report diagnosed a middle ear adenoma. Discussion. Middle ear glandular tumors are extremely rare and, despite numerous histological techniques, continue to defy satisfactory classification. Most surgeons advocate surgical excision though evidence of the tumour's natural course and risk of recurrence is lacking.

Vrugt, B.; Huber, A. M.

2014-01-01

131

Finite element analysis of middle ear mechanics  

NASA Astrophysics Data System (ADS)

An essential component in the process of hearing is the transformation of sound from acoustic to mechanical vibration in the middle ear. In order to study this phenomenon, computational models have been introduced to model the behavior of the tympanic membrane and its interaction with the surrounding acoustical spaces. Using such a computational model, one gains an increased understanding of the relationship between its structure and performance, which may assist in preventive, diagnostic, and reconstructive medical applications. The goal of this present work is to expand the computational simulation capabilities of current eardrum models using modern finite element modeling techniques. A fully coupled structural acoustic model is presented using modern shell element technology. Anatomical geometries for the eardrum, acoustic spaces of the ear canal and middle ear cavity, and the ossicles are utilized via muCT imaging. A new computational algorithm is used to compute the frequency response of this model over a wide frequency range. This approach uses the matrix Pade-via-Lanczos algorithm to construct reduced-order models around chosen reference frequencies, which can be solved efficiently at many frequencies within a frequency window. An adaptive algorithm is introduced to span a given frequency range by introducing new reference frequencies as necessary. Results for the middle ear model, using this multifrequency algorithm, are presented for intact and modified middle ear anatomies. These modifications serve to demonstrate the utility of the computational approach in understanding the relationships between the morphological structure of the middle ear and its functionality.

Tuck-Lee, James Peter

132

Mutations affecting development of the zebrafish ear.  

PubMed

In a large scale screen for genetic defects in zebrafish embryogenesis we identified mutations affecting several aspects of ear development, including: specification of the otic placode, growth of the otic vesicle (otocyst), otolith formation, morphogenesis of the semicircular canals and differentiation of the otic capsule. Here we report initial phenotypic and genetic characterization of 20 of these mutations defining 13 independent loci. Embryos mutant at the quadro locus display abnormal specification of the otic placode. As revealed by dlx-3 expression, the otic field in the mutant embryos is smaller or split into two fields. At later stages of development the ear of quadro mutants is frequently divided into two smaller, incomplete units. Four loci affect ear shape shortly after formation of the otic vesicle. All of them also display abnormal brain morphology. Mutations in five loci result in the absence of otolith formation; two of these also produce changes of ear morphology. Two loci, little richard and golas, affect morphology of the otic vesicle shortly before formation of the semicircular canals. In both cases the morphogenesis of the semicircular canals is disrupted. Finally, the antytalent locus is involved in late expansion of the ear structure. Analysis of mutations presented here will strengthen our understanding of vertebrate ear morphogenesis and provide novel entry points to its genetic analysis. PMID:9007247

Malicki, J; Schier, A F; Solnica-Krezel, L; Stemple, D L; Neuhauss, S C; Stainier, D Y; Abdelilah, S; Rangini, Z; Zwartkruis, F; Driever, W

1996-12-01

133

Lipoxygenase metabolites of arachidonic acid as second messengers for presynaptic inhibition of Aplysia sensory cells  

Microsoft Academic Search

Biochemical and biophysical studies on Aplysia sensory neurons indicate that inhibitory responses to the molluscan peptide FMRFamide are mediated by lipoxygenase metabolites of arachidonic acid. These compounds are a new class of second messengers in neurons.

D. Piomelli; A. Volterra; N. Dale; S. A. Siegelbaum; E. R. Kandel; J. H. Schwartz; F. Belardetti

1987-01-01

134

Arachidonate activates muscle electrogenic sodium pump and brain microsome Na+,K+-ATPase under suboptimal conditions.  

PubMed

Arachidonate 5 x 10(-5) mol.l-1 increased the rate of hyperpolarization induced in Na+-loaded mouse diaphragm fibers by 5 mmol.l-1 K+. When applied to Na+-loaded muscles without potassium, arachidonate 1 x 10(-6) and 5 x 10(-5) mol.l-1 induced a ouabain-sensitive hyperpolarization of the muscle fibers. The activity of rat brain microsomal Na+,K+-ATPase was stimulated by 1 x 10(-7)-5 x 10(-6) mol.l-1 arachidonate in reaction media with reduced amounts of ATP or K+ and after short-lasting sonication of the samples. It was concluded that, under particular conditions, arachidonate might serve as a Na+,K+-ATPase activator or inhibitor regulating its ion transport and electrogenicity. PMID:2825927

Vyskocil, F; Zemková, H; Teisinger, J; Svoboda, P

1987-12-01

135

Delayed ear reconstruction: case report of reconstruction of an avulsed ear 2 days after injury.  

PubMed

Auricular reattachment and reconstruction following traumatic ear avulsion is a challenging surgical problem. Suggested reconstruction methods include direct reattachment, composite grafting, pocket methods, coverage with periauricular flaps, and microsurgical repair. A published alternative is reattachment and burial of the amputated part under a postauricular flap. If circumstances delay the surgical intervention, what is a safe window to still consider this form of treatment? In the current report, we present a case of a complete partial ear avulsion, which was reattached in the ER as a free graft. Two days later the cartilage was banked under a postauricular flap. A 22 year-old male had his ear was completely bitten off which was re-attached. Two days later the skin of the avulsed segment was dark and bloodless. The avulsed segment was removed from the ear. The overlying skin was dissected off of the attached ear leaving perichondrium on the medial aspect of the ear. The cartilage was then reattached. A postauricular pocket/flap was created and the ear tucked and secured to the postauricular fascia and skin closed overtop. Five weeks later, the patient had division and inset of the flap with a full thickness skin graft to the posterior aspect of the ear. Our results and experiences suggest that immediate reconstruction may not be crucial. PMID:24793138

Brockhoff, Hans C; Zide, Michael

2014-07-01

136

Influence of fatty acid ethanolamides and ? 9-tetrahydrocannabinol on cytokine and arachidonate release by mononuclear cells  

Microsoft Academic Search

The effects of arachidonic acid ethanolamide (anandamide), palmitoylethanolamide and ?9-tetrahydrocannabinol on the production of tumor necrosis factor-? (TNF-?), interleukin-4, interleukin-6, interleukin-8, interleukin-10, interferon-?, p55 and p75 TNF-? soluble receptors by stimulated human peripheral blood mononuclear cells as well as [3H]arachidonic acid release by non-stimulated and N-formyl-Met–Leu–Phe (fMLP)-stimulated human monocytes were investigated. Anandamide was shown to diminish interleukin-6 and interleukin-8 production

Evguenii V Berdyshev; Elisabeth Boichot; Noëlla Germain; Nathalie Allain; Jean-Pierre Anger; Vincent Lagente

1997-01-01

137

Virus-induced enhancement of arachidonate metabolism by bovine alveolar macrophages in vitro  

SciTech Connect

Virus infection of alveolar macrophages both in vivo and in vitro has been associated with a variety of changes in cellular function. Some of these changes are identical to the effects that arachidonate-derived mediators, prostaglandins, leukotrienes, and hydroxyeicosatetraenoic acids, have on macrophage function. Virus infection of macrophages has been previously shown to increase the output of some arachidonate metabolites, most notably PGE2. However, the effect of virus infection on arachidonate metabolism in general has not been well described. In our experiments, primary cultures of alveolar macrophages obtained from normal cattle by bronchoalveolar lavage, were infected in vitro with parainfluenza type 3 virus. At days 0 to 4 post-infection (p.i.) these cells were labelled with 3H-arachidonic acid and stimulated with either serum-coated zymosan, the calcium ionophore A23187, or phorbol myristate acetate. The complete spectrum of arachidonate-derived metabolites was determined by reverse-phase high performance liquid chromatography with UV and on-line radiometric monitoring of column eluant. The total output of metabolites of arachidonic acid by virus-infected alveolar macrophages was increased over that of noninfected controls (with all stimuli tested) by day 4 p.i. (P less than or equal to 0.05). The production of metabolites by the cyclooxygenase, 12- and 5-lipoxygenase enzyme systems was significantly increased, as was the release of 3H-arachidonate. The lack of stimulus specificity and the increases in arachidonate release suggest that greater substrate availability, due either to increased phospholipase activity or direct virus-membrane interaction, may be responsible for the virus-induced enhancement of metabolite output.

Laegreid, W.W.; Taylor, S.M.; Leid, R.W.; Silflow, R.M.; Evermann, J.R.; Breeze, R.G.; Liggitt, H.D.

1989-04-01

138

Selective channelling of arachidonic and linoleic acids into glycerolipids of rat hepatocytes in primary culture.  

PubMed Central

Rat hepatocytes in primary culture were incubated with a mixture of linoleic and arachidonic acid at various total fatty acid/serum albumin molar ratios. Mixed fatty acids were taken up at the same rate and distributed with the same pattern as fatty acids added separately. The rates of total uptake, incorporation into hepatocyte and secreted triacylglycerols and beta-oxidation were linearly related to the fatty acid/albumin ratios, whereas the rate of incorporation into phospholipids was saturable. Neither the uptake rate nor the distribution of both fatty acids considered together varied with the arachidonic acid/linoleic acid molar ratio. Changes in this ratio and in the uptake rate led to significant variations in the respective fate of the fatty acids. The preferential channelling of arachidonic acid versus linoleic acid into beta-oxidation and phosphatidylinositol was greatest at a low uptake rate and then decreased as the uptake rose. Conversely, the preferential channelling of arachidonic acid versus linoleic acid into phosphatidylcholine, but not phosphatidylethanolamine, increased with the uptake rate. Moreover, both arachidonic acid and linoleic acid were preferentially incorporated into the 1-palmitoyl molecular species of phosphatidylcholine and phosphatidylethanolamine at a low uptake rate, and of phosphatidylcholine at a high uptake rate. This could be related to the synthesis of biliary phosphatidylcholine, of which 1-palmitoyl-2-linoleoyl and 1-palmitoyl-2-arachidonoyl are the main molecular species. Linoleic and arachidonic acid were selectively distributed into distinct metabolic pools of triacylglycerol, the intrahepatocyte pool which preferentially incorporated linoleic acid at a low uptake rate and the secreted pool in which the relative enrichment of arachidonic acid increased with the uptake rate. This strengthens the central role of hepatic secretion in the supply of arachidonic acid to peripheral tissues. Images Fig. 3.

Thomas, G; Loriette, C; Pepin, D; Chambaz, J; Bereziat, G

1988-01-01

139

Predominant Generation of 15-lipoxygenase Metabolites of Arachidonic Acid by Epithelial Cells from Human Trachea  

Microsoft Academic Search

Epithelial cells of 99% purity and 92% viability were isolated from human tracheas obtained post mortem, and the cellular pathways for lipoxygenation of arachidonic acid were examined in vitro. The lipoxygenase metabolites were identified by comparison with synthetic standards during reversed-phase and straight-phase high-pressure liquid chromatography, UV spectroscopy, and gas chromatography\\/mass spectrometry. Epithelial cells incubated without arachidonic acid failed to

J. A. Hunter; W. E. Finkbeiner; J. A. Nadel; E. J. Goetzl; M. J. Holtzman

1985-01-01

140

Plasma phospholipid arachidonic acid content and calcium metabolism in idiopathic calcium nephrolithiasis  

Microsoft Academic Search

Plasma phospholipid arachidonic acid content and calcium metabolism in idiopathic calcium nephrolithiasis.BackgroundReports of an increase in plasma and erythrocyte phospholipid arachidonic acid content and in urinary prostaglandin E2 (PGE2) excretion in patients with idiopathic calcium nephrolithiasis suggested their crucial role in the pathogenesis of hypercalciuria, a well-known risk factor for lithogenesis.MethodsTo confirm this hypothesis, 15 healthy subjects and 20 nephrolithiasis

Bruno Baggio; Alessandro Budakovic; Maria Angela Nassuato; Giuseppe Vezzoli; Enzo Manzato; Giovanni Luisetto; Martina Zaninotto

2000-01-01

141

Clearance and metabolism of arachidonic acid by C6 glioma cells and astrocytes  

Microsoft Academic Search

Effects of increased levels of arachidonic acid (AA) were analyzed in vitro by employment of C6 glioma cells and astrocytes from primary culture. The cells were suspended in a physiological medium added with arachidonic acid (AA) in a concentration range from 0.01 to 0.5 mM. The concentration profiles of the fatty acid and AA-metabolited were subsequently followed for 90 min.

Frank Staub; Andrea Winkler; Jiirgen Peters; Ulrike Goerke; Oliver Kempski; Alexander Baethmann

1995-01-01

142

Cytochrome P450 Metabolites of Arachidonic Acid as Intracellular Signaling Molecules in Vascular Tissue  

Microsoft Academic Search

Recent studies from our laboratory have indicated that vascular smooth muscle cells (VSMC) metabolize arachidonic acid via a P4504A-dependent pathway to 20-hydroxyeicosatetraenoic acid (20-HETE), and that this system serves as a novel signal transduction pathway that plays a central role in the regulation of vascular tone. The major metabolite of arachidonic acid formed in cerebral and renal arteries is 20-HETE.

David R. Harder; Andrew R. Lange; Debebe Gebremedhin; Eric K. Birks; Richard J. Roman

1997-01-01

143

Activation and regulation of arachidonic acid release in rabbit peritoneal neutrophils  

SciTech Connect

Arachidonic acid release in rabbit neutrophils can be enhanced by the addition of chemotactic fMet-Leu-Phe, platelet-activating factor, PAF, or the calcium ionophore A23187. Over 80% of the release ({sup 3}H)arachidonic acid comes from phosphatidylcholine and phosphatidylinositol. The release is dose-dependent and increases with increasing concentration of the stimulus. The A23187-induced release increases with increasing time of the stimulation. ({sup 3}H)arachidonic acid release, but not the rise in the concentration of intracellular calcium, is inhibited in pertussis toxin-treated neutrophils stimulated with PAF. The ({sup 3}H)arachidonic acid released by A23187 is potentiated while that release by fMET-Leu-Phe or PAF is inhibited in phorbol 12-myristate 13-acetate, PMA, treated rabbit neutrophils. The protein kinase C inhibitor 1-(5-isoquinoline sulfonyl)-2-methylpiperazine, H-7, has no effect on the potentiation by PMA of the A23187-induced release, it prevents the inhibition by PMA of the release produced by PAF or fMet-Leu-Phe. In addition, PMA increases arachidonic acid release in H-7-treated cells stimulated with fMet-Leu-Phe. The diacylglycerol kinase inhibitor R59022 increases the level of diacylglycerol in neutrophils stimulated with fMet-Leu-Phe. Furthermore, R59022 potentiates ({sup 3}H) arachidonic acid release produced by fMet-Leu-Phe. This potentiation is not inhibited by H-7, in fact, it is increased in H-7-treated neutrophils.

Tao, W.

1988-01-01

144

Arachidonic acid stimulates /sup 45/calcium efflux and HPL release in isolated trophoblast cells  

SciTech Connect

Previous investigations from this laboratory have indicated that arachidonic acid stimulates a rapid, dose-dependent and reversible increase in hPL release which is not dependent on cyclooxygenase or lipoxygenase metabolism. To investigate further the mechanism by which arachidonic acid stimulates the release of hPL, the effect of arachidonic acid on the release of /sup 45/Ca from perifused cells prelabelled with /sup 45/Ca was examined in an enriched cell culture population of term human syncytiotrophoblast. Arachidonic acid (10-100 ..mu..M) stimulated a dose-dependent, rapid, and reversible increase in the release of both /sup 45/Ca and hPL from the perifused placental cells. On the other hand, palmitic acid had little effect on either hPL release or /sup 45/Ca release even at concentrations as high as 100 ..mu..M. Ionophore A23187 (1-10..mu..M) also stimulated a dose-dependent and reversible increase in hPL release. Since arachidonic acid increases the mobilization of cellular calcium, as reflected by the increased /sup 45/calcium efflux, and since an increase in the intracellular calcium concentration appears to stimulate an increase in hPL release, these results suggest that the stimulation of hPL release by arachidonic acid may be due, at least in part, to the effects of the fatty acid on cellular calcium mobilization. 26 references, 5 figures.

Zeitler, P.; Murphy, E.; Handwerger, S.

1986-01-13

145

MICROARRAY ANALYSIS OF DICHLOROACETIC ACID-INDUCED CHANGES IN GENE EXPRESSION  

EPA Science Inventory

MICROARRAY ANALYSIS OF DICHLOROACETIC ACID-INDUCED CHANGES IN GENE EXPRESSION Dichloroacetic acid (DCA) is a major by-product of water disinfection by chlorination. Several studies have demonstrated the hepatocarcinogenicity of DCA in rodents when administered in dri...

146

Assessment of ear disorders using power reflectance.  

PubMed

This article describes the effect of various pathologies on power reflectance (PR) and absorbance measured in human adults. The pathologies studied include those affecting the tympanic membrane, the middle-ear ossicles, the middle-ear cavity, the inner ear, and intracranial pressure. Interesting pathology-induced changes in PR that are statistically significant have been reported. Nevertheless, because measurements of PR obtained from normal-hearing subjects have large variations and some pathology-induced changes are small, it can be difficult to use PR alone for differential diagnosis. There are, however, common clinical situations without reliable diagnostic methods that can benefit from PR measurements. These conditions include ears with a normal-appearing tympanic membrane, aerated middle-ear cavity, and unknown etiology of conductive hearing loss. PR measurements in conjunction with audiometric measurements of air–bone gap have promise in differentiating among stapes fixation, ossicular discontinuity, and superior semicircular canal dehiscence. Another possible application is to monitor an individual for possible changes in intracranial pressure. Descriptions of mechanisms affecting PR change and utilization of PR measurements in clinical scenarios are presented. PMID:23900180

Nakajima, Hideko Heidi; Rosowski, John J; Shahnaz, Navid; Voss, Susan E

2013-07-01

147

Passive and active middle ear implants  

PubMed Central

Besides eradication of chronic middle ear disease, the reconstruction of the sound conduction apparatus is a major goal of modern ear microsurgery. The material of choice in cases of partial ossicular replacement prosthesis is the autogenous ossicle. In the event of more extensive destruction of the ossicular chain diverse alloplastic materials, e.g. metals, ceramics, plastics or composits are used for total reconstruction. Their specialised role in conducting sound energy within a half-open implant bed sets high demands on the biocompatibility as well as the acoustic-mechanic properties of the prosthesis. Recently, sophisticated titanium middle ear implants allowing individual adaptation to anatomical variations are widely used for this procedure. However, despite modern developments, hearing restoration with passive implants often faces its limitations due to tubal-middle-ear dysfunction. Here, implantable hearing aids, successfully used in cases of sensorineural hearing loss, offer a promising alternative. This article reviews the actual state of affairs of passive and active middle ear implants.

Beutner, Dirk; Huttenbrink, Karl-Bernd

2011-01-01

148

Evaluation for waterproof ear protectors in swimmers.  

PubMed

The middle ear cavity is exposed and vulnerable to waterborne infection in patients with grommets, perforated tympanic membranes and after radical mastoidectomy. Patients suffering from chronic otitis externa and those receiving radiotherapy to the head and neck also have an increased susceptibility to such infections. Many advocate the use of waterproof ear protectors in such patients when swimming. The choice of a suitable ear protector is complicated as many are now available commercially. This study was therefore designed to evaluate the degree of protection afforded by seven different ear protectors in a group of six swimmers. A very sensitive, original method of water detection was devised incorporating a pH indicator strip. The results showed conclusively that cotton wool coated in paraffin jelly BPC was the most effective method of ear protection and was found to be comfortable and easy to use. Other methods, including custom-made silicone rubber plugs, were not adequate in sealing the external auditory canal and are considerably more expensive. PMID:2614235

Robinson, A C

1989-12-01

149

Assessment of Ear Disorders Using Power Reflectance  

PubMed Central

This paper describes the effect of various pathologies on power reflectance (PR) and absorbance measured in human adults. The pathologies studied include those affecting the tympanic membrane, the middle-ear ossicles, the middle-ear cavity, the inner ear, and intracranial pressure. Interesting pathology-induced changes in PR that are statistically significant have been reported. Nevertheless, because measurements of PR obtained from normal-hearing subjects have large variations and some pathology-induced changes are small, it can be difficult to use PR alone for differential diagnosis. There are, however, common clinical situations without reliable diagnostic methods that can benefit from PR measurements. These conditions include ears with a normal-appearing tympanic membrane, aerated middle-ear cavity and unknown etiology of conductive hearing loss. PR measurements in conjunction with audiometric measurements of air-bone gap have promise in differentiating among stapes fixation, ossicular discontinuity and superior semicircular canal dehiscence. Another possible application is to monitor an individual for possible changes in intracranial pressure. Descriptions of mechanisms affecting PR change and utilization of PR measurements in clinical scenarios are presented.

Nakajima, Hideko Heidi; Rosowski, John J.; Shahnaz, Navid; Voss, Susan E.

2013-01-01

150

Ancestral genetic complexity of arachidonic acid metabolism in Metazoa.  

PubMed

Eicosanoids play an important role in inducing complex and crucial physiological processes in animals. Eicosanoid biosynthesis in animals is widely reported; however, eicosanoid production in invertebrate tissue is remarkably different to vertebrates and in certain respects remains elusive. We, for the first time, compared the orthologs involved in arachidonic acid (AA) metabolism in 14 species of invertebrates and 3 species of vertebrates. Based on parsimony, a complex AA-metabolic system may have existed in the common ancestor of the Metazoa, and then expanded and diversified through invertebrate lineages. A primary vertebrate-like AA-metabolic system via cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) pathways was further identified in the basal chordate, amphioxus. The expression profiling of AA-metabolic enzymes and lipidomic analysis of eicosanoid production in the tissues of amphioxus supported our supposition. Thus, we proposed that the ancestral complexity of AA-metabolic network diversified with the different lineages of invertebrates, adapting with the diversity of body plans and ecological opportunity, and arriving at the vertebrate-like pattern in the basal chordate, amphioxus. PMID:24801744

Yuan, Dongjuan; Zou, Qiuqiong; Yu, Ting; Song, Cuikai; Huang, Shengfeng; Chen, Shangwu; Ren, Zhenghua; Xu, Anlong

2014-09-01

151

Arachidonate lipoxygenases as essential regulators of cell survival and apoptosis.  

PubMed Central

Arachidonic acid (AA) metabolites derived from both cyclooxygenase (COX) and lipoxygenase (LOX) pathways transduce a variety of signals related to cell growth. Here, we report that the AA LOX pathway also functions as a critical regulator of cell survival and apoptosis. Rat Walker 256 (W256) carcinosarcoma cells express 12-LOX and synthesize 12(S)- and 15(S)-hydroxyeicosatetraenoic acids as their major LOX metabolites. W256 cells transfected with 12-LOX-specific antisense oligonucleotide or antisense oligonucleotides directed to conserved regions of LOXs underwent time- and dose-dependent apoptosis. Likewise, treatment of W256 cells with various LOX but not COX inhibitors induced apoptotic cell death, which could be partially inhibited by exogenous 12(S)- or 15(S)-hydroxyeicosatetraenoic acids. The W256 cell apoptosis induced by antisense oligos and LOX inhibitors was followed by a rapid downregulation of bcl-2 protein, a dramatic decrease in the bcl-2/bax ratio, and could be suppressed by bcl-2 overexpression. In contrast, p53, which is wild type in W256 cells, did not undergo alterations during apoptosis induction. The results suggest that the LOX pathway plays an important physiological role in regulating apoptosis. Images Fig. 1 Fig. 2 Fig. 4

Tang, D G; Chen, Y Q; Honn, K V

1996-01-01

152

Signal transduction by interferon-. alpha. through arachidonic acid metabolism  

SciTech Connect

Molecular mechanisms that mediate signal transduction by growth inhibitory cytokines are poorly understood. Type 1 ({alpha} and {beta}) interferons (IFNs) are potent growth inhibitory cytokines whose biological activities depend on induced changes in gene expression. IFN-{alpha} induced the transient activation of phospholipase A{sub 2} in 3T3 fibroblasts and rapid hydrolysis of ({sup 3}H)arachidonic acid (AA) from prelabeled phospholipid pools. The phospholipase inhibitor, bromophenacyl bromide (BPB), specifically blocked IFN-induced binding of nuclear factors to a conserved, IFN-regulated enhancer element, the interferon-stimulated response element (ISRE). BPB also caused a dose-dependent inhibition of IFN-{alpha}-induced ISRE-dependent transcription in transient transfection assays. Specific inhibition of AA oxygenation by eicosatetraynoic acid prevented IFN-{alpha} induction of factor binding to the ISRE. Treatment of intact cells with inhibitors of fatty acid cyclooxygenase or lipoxygenase enzymes resulted in amplification of IFN-{alpha}-induced ISRE binding and gene expression. Thus, IFN-{alpha} receptor-coupled AA hydrolysis may function in activation of latent transcription factors by IFN-{alpha} and provides a system for studying the role of AA metabolism in transduction of growth inhibitory signals.

Hannigan, G.E.; Williams, B.R.G. (Univ. of Toronto, Ontario (Canada))

1991-01-11

153

Primary ear fibroblast derivation from mice.  

PubMed

Mouse embryonic fibroblasts (MEFs) are commonly utilized as a primary cell culture model and have several advantages over other types of ex vivo-derived cells. However, the successful generation of MEFs is time consuming and requires a certain level of mouse expertise to successfully complete. Thus, primary ear-derived fibroblasts offer an acceptable alternative to MEFs. Fibroblasts derived from the pinna of adult mice are easily attainable with minimal skill, proliferate rapidly, and are easy to manipulate. Likewise, because they are derived from adult mice, other organs can be concurrently harvested for the isolation of additional types of primary cells. Similar to MEFs, ear fibroblasts are an excellent ex vivo model system to study mechanisms associated with virus infection and produce a diverse array of inflammatory mediators, such as cytokines and interferon. Here, we describe a highly versatile and simple method for the derivation, maintenance, and viral challenge of primary ear-derived fibroblasts from mice. PMID:23824888

Moore, Chris B; Allen, Irving C

2013-01-01

154

Ear lobule reconstruction using nasal septal cartilage.  

PubMed

Surgical reconstruction of an earlobe requires adequate support without sacrificing the delicacy necessary for an attractive result. A two-stage ear lobule reconstruction using a mastoid skin pocket and cartilage from the nasal septum was performed in six patients. The earlobe aesthetics were acceptable and allowed ear piercing. There were no major complications, including no loss of flap, graft extrusion, septal perforation, or infection. Range of follow-up was 1 to 6 years, with an average of 3 years. No revisions have been performed. A two-stage technique for ear lobule reconstruction is described using septal cartilage to preserve shape and definition that has the additional advantage of minimal morbidity. PMID:23542248

Bastidas, Nicholas; Jacobs, Jordan M S; Thorne, Charles H

2013-04-01

155

Precise individualized armature for ear reconstruction  

NASA Astrophysics Data System (ADS)

The cosmetic result of an ear restored surgically or via prosthetics is dependent on the surgeon''s ability to carve a precise cartilage armature at the time of surgery or the prosthetist''s ability to sculpt in wax an exact duplicate of the patient''s " missing" ear. Introducing CAD/CAM technology into the process benefits the esthetic outcome of these procedures. By utilizing serial section information derived from CAT MRI or moulage techniques a mirrorimage of the patient''s " donor" ear is generated. The resulting earform data is then used for the design of a cartilage armature produced by multi-axis milling or to produce by stereolithography a model which serves as the basis for a prosthesis.

Evenhouse, Raymond J.; Chen, Xiaoming

1991-04-01

156

Congenital Dermoid Cyst of the Middle Ear  

PubMed Central

Dermoid cysts of the head and neck are rare lesions comprised of epidermal and mesodermal elements. We report a dermoid cyst presenting in the middle ear of the youngest patient reported to date. Structures of endodermal descent were also identified, but, given that the entire middle ear mucosa is of endodermal origin, specific classification as a teratoma would be imprecise. This lesion is interesting in that it did not directly involve the mastoid. Possible embryologic sites of origin are discussed. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5

Farris, Paul E.; Meyerhoff, William L.; Vuitch, Frank

1998-01-01

157

Docosahexaenoic acid induces apoptosis in Jurkat cells by a protein phosphatase-mediated process  

Microsoft Academic Search

Docosahexaenoic acid (DHA) is an omega-3 fatty acid under intense investigation for its ability to modulate cancer cell growth and survival. This research was performed to study the cellular and molecular effects of DHA. Our experiments indicated that the treatment of Jurkat cells with DHA inhibited their survival, whereas similar concentrations (60 and 90 ?M) of arachidonic acid and oleic

Rafat A. Siddiqui; Laura J. Jenski; Kristiana Neff; Kevin Harvey; Richard J. Kovacs; William Stillwell

2001-01-01

158

Saturated FFAs, Palmitic Acid and Stearic Acid, Induce Apoptosis in Human Granulosa Cells  

Microsoft Academic Search

Obesity is associated with insulin resistance and some repro- ductive abnormalities. Circulating FFAs are often elevated in obese subjects and are also closely linked to insulin resis- tance. In this study, we demonstrated that saturated FFAs, such as palmitic acid and stearic acid, markedly suppressed the granulosa cell survival in a time- and dose-dependent manner. Polyunsaturated FFA, arachidonic acid, had

YI-MING MU; TOSHIHIKO YANASE; YOSHIHIRO NISHI; ATSUSHI TANAKA; MASAYUKI SAITO; CHENG-HAO JIN; CHIZU MUKASA; TAIJIRO OKABE; MASATOSHI NOMURA; KIMINOBU GOTO; HAJIME NAWATA

2010-01-01

159

Tranexamic acid induces kaolin intake stimulating a pathway involving tachykinin neurokinin 1 receptors in rats.  

PubMed

Tranexamic acid suppresses post-partum haemorrhage and idiopathic menorrhagia through its anti-fibrinolytic action. Although it is clinically useful, it is associated with high risks of side effects such as emesis. Understanding the mechanisms underlying tranexamic acid-induced emesis is very important to explore appropriate anti-emetic drugs for the prevention and/or suppression of emesis. In this study, we examined the receptors involved in tranexamic acid-induced kaolin intake in rats, which reflects the drug's clinical emetogenic potential in humans. Further, we examined the brain regions activated by administration of tranexamic acid and elucidated pivotal pathways of tranexamic acid-induced kaolin intake. We examined the effects of ondansetron, a 5-hydroxytryptamine 3 receptor antagonist, domperidone, a dopamine 2 receptor antagonist, and aprepitant, a tachykinin neurokinin 1 (NK1) receptor antagonist, on tranexamic acid-induced kaolin intake in rats. Then, we determined the brain regions that showed increased numbers of c-Fos immunoreactive cells. Finally, we examined the effects of an antagonist(s) that reduced tranexamic acid-induced kaolin intake on the increase in c-Fos immunoreactive cells. Aprepitant significantly decreased tranexamic acid-induced kaolin intake. However, neither ondansetron nor domperidone decreased kaolin intake. Tranexamic acid significantly increased c-Fos immunoreactive cells by approximately 5.5-fold and 22-fold in the area postrema and nucleus of solitary tract, respectively. Aprepitant decreased the number of c-Fos immunoreactive cells in both areas. Tranexamic acid induced kaolin intake possibly via stimulation of tachykinin NK1 receptors in rats. The tachykinin NK1 receptor could be targeted to prevent and/or suppress emesis in patients receiving tranexamic acid. PMID:24333477

Kakiuchi, Hitoshi; Kawarai-Shimamura, Asako; Kuwagata, Makiko; Orito, Kensuke

2014-01-15

160

Acoustics of the human middle-ear air space  

NASA Astrophysics Data System (ADS)

The impedance of the middle-ear air space was measured on three human cadaver ears with complete mastoid air-cell systems. Below 500 Hz, the impedance is approximately compliance-like, and at higher frequencies (500-6000 Hz) the impedance magnitude has several (five to nine) extrema. Mechanisms for these extrema are identified and described through circuit models of the middle-ear air space. The measurements demonstrate that the middle-ear air space impedance can affect the middle-ear impedance at the tympanic membrane by as much as 10 dB at frequencies greater than 1000 Hz. Thus, variations in the middle-ear air space impedance that result from variations in anatomy of the middle-ear air space can contribute to inter-ear variations in both impedance measurements and otoacoustic emissions, when measured at the tympanic membrane.

Stepp, Cara E.; Voss, Susan E.

2005-08-01

161

[An ear thermometer based on infrared thermopiles sensor].  

PubMed

According to the development of body temperature measurement mode, an ear thermometer with infrared thermopiles sensor is designed for body thermometry Compared with oral thermometer, the accuracy of ear thermometer is acceptable. PMID:24409789

Xie, Haiyuan; Qian, Mingli

2013-09-01

162

Inner ear damage due to lipoid nephrosis  

Microsoft Academic Search

Inner ear pathology was studied in adult rats with lipoid nephrosis induced by puromycin aminonucleoside. Although no abnormality was observed in auditory brain-stem responses, significant changes were noted in the stria vascularis. The most striking observation was that intermediate cells were markedly swelled, there-by pressing adjacent marginal cells. Severely affected marginal cells have vacuoles and increased lysosomes and protruded toward

H. Yamane; Y. Nakai

1993-01-01

163

Do Your Ears Pop in Space?  

Microsoft Academic Search

R Mike Mullane is a US astronaut who has flown into space three times on the Space Shuttle. He resigned from NASA in 1990 and has since pursued a career as a professional speaker and author. Do Your Ears Pop in Space? is his third book, and is based on the simple idea of writing down the 500 questions he

Robert Lambourne

1997-01-01

164

Play It by Ear. Hearing Conservation Curriculum.  

ERIC Educational Resources Information Center

This curriculum was designed to help teachers teach their fourth-grade students about hearing and the effects of loud noises on hearing. The program describes the human ear and how it works, explains the health effects of noise, and offers ways for students to protect their hearing from unsafe noise levels. Students are taught how hearing is…

Olson, Dianne R.

165

Keep Your Ear-Lids Open.  

ERIC Educational Resources Information Center

This article suggests that the development of listening skills should extend to the "soundscape" of nonspeech acoustical information. It presents a model for effective aural processing, identifies categories of information obtained from nonverbal sound, and explores "ear-tuning" or listening exercises that use sound to glean information about…

Ferrington, Gary

1994-01-01

166

Evolution of Gravity Receptors in the Ear.  

National Technical Information Service (NTIS)

The general status of a grant to investigate the origins and evolution of two hair cell types in the ears of a teleost fish, Astronotus ocellatus (the oscar), is presented. First, it was demonstrated that the cells in the rostral end of the saccule of the...

A. N. P. I. Popper

1996-01-01

167

Force field feature extraction for ear biometrics  

Microsoft Academic Search

The overall objective in defining feature space is to reduce the dimensionality of the original pattern space, whilst maintaining discriminatory power for classification. To meet this objec- tive in the context of ear biometrics a new force field transformation treats the image as an array of mutually attracting particles that act as the source of a Gaussian force field. Under-

David J. Hurley; Mark S. Nixon; John N. Carter

2005-01-01

168

Getting Teens to Read with Their Ears  

ERIC Educational Resources Information Center

Audiobooks have been around for years in various formats, like cassette tapes and CDs. This article describes a new type of audiobook on the market which is generating an interest in "reading." The device, called Playaway, is the size of a MP3 player and comes with a lanyard and ear buds. Buttons on the back of the player control the speed and…

Fues, Marianne Cole

2009-01-01

169

Production of metabolic products of arachidonic acid during cell-cell interactions  

SciTech Connect

Interactions of human platelets and neutrophils were studied with particular reference to the arachidonic acid pathway. Suspensions of (3H)arachidonate-labeled platelets and unlabeled neutrophils were stimulated with ionophore A23187. We detected several radioactive arachidonate metabolites, which are not produced by platelets alone. These included (3H)-labeled leukotriene B4 (LTB4), dihydroxy-eicosatetraeonic acid (DiHETE), and 5-hydroxy-eicosatetraenoic acid (5-HETE). DiHETE was formed when the platelet product (3H)12-HETE was added to ionophore-stimulated neutrophils. In addition, DiHETE was the major metabolite when (3H)5-HETE, a neutrophil arachidonate product, was added to stimulated platelets. We therefore suggest that upon stimulation, platelet-derived arachidonate can serve as precursor for the neutrophil-derived eicosanoids LTB4 and 5-HETE, and the platelet-derived product 12-HETE can be metabolized to DiHETE by stimulated human neutrophils. More recently we have shown that 12-HETE from thrombin-stimulated platelets can also be metabolized to a new product, 12,20-DiHETE, by

Marcus, A.J.; Safier, L.B.; Broekman, M.J.; Ullman, H.L.; Islam, N.; Sorrell, T.C.; Serhan, C.N.; Weissmann, G.; Oglesby, T.D.; Gorman, R.R.

1984-09-01

170

Metabolism of arachidonic and adrenic acids in molecular species of gycerophospholipids in mouse brain  

SciTech Connect

Arachidonic acid, the precursor of prostaglandins and other eicosanoids, is very important for normal function and pathophysiology in nearly all tissues. The content of arachidonic acid is particularly large in the brain which also contains relatively large amounts of adrenic acid, the elongation product of arachidonic acid. These fatty acids are found in the glycerophospholipids. Unesterified (/sup 3/H)arachidoninc acid (20:4) and (/sup 14/C)adrenic acid (22:4) complexed to bovine serum albumin, were simultaneously injected into the left lateral ventricles of C3H mice. A 400-fold larger mass of 22:4 relative to 20:4 was used. At selected times following injection, brains were frozen and lipids were extracted for analysis of incorporation of radioactivity into diacylglycerols, tricyglycerols, total phospholipids, and the molecular species ethanolamine, choline and inositol glycerophospholipids. The greatest uptake of arachidonic acid was found in some molecular species of the choline plasmalogens. This suggests an important function for such molecules. The suggested function is in signal transduction across cell membranes following activation of receptors. This process may stimulate the hydrolysis of choline plasmalogens with the release of arachidonic acid which can then be metabolized to prostaglandins, leukotrienes, or other biologically potent compounds.

Harder, H.W.

1986-01-01

171

Toward Unconstrained Ear Recognition From Two-Dimensional Images  

Microsoft Academic Search

Ear recognition, as a biometric, has several advantages. In particular, ears can be measured remotely and are also relatively static in size and structure for each individual. Unfortunately, at present, good recognition rates require controlled conditions. For commercial use, these systems need to be much more robust. In particular, ears have to be recognized from different angles (poses), under different

John D. Bustard; Mark S. Nixon

2010-01-01

172

15 CFR 734.2 - Important EAR terms and principles.  

Code of Federal Regulations, 2013 CFR

...part. Publicly available technology and software not subject to the EAR are described in...States, or release of technology or software subject to the EAR to a foreign national...encryption source code and object code software subject to the EAR. (2) Export...

2013-01-01

173

Graph Ear Decompositions and Graph Embeddings (Extended Abstract)  

Microsoft Academic Search

Ear decomposition of a graph has been extensively studied in relation to graph connectivity. In this paper, a connection of ear decomposition to graph embeddings is exhibited. It is shown that constructing a maximumpaired ear decomposition of a graph and constructing a maximum-genus embedding of the graph are O (e log n)-time equivalent. This gives a polynomial time algorithm for

Jianer Chen; Saroja P. Kanchi

1993-01-01

174

21 CFR 874.3430 - Middle ear mold.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Middle ear mold. 874.3430 Section 874.3430 Food and...Prosthetic Devices § 874.3430 Middle ear mold. (a) Identification. A middle ear mold is a preformed device that is...

2009-04-01

175

21 CFR 874.3430 - Middle ear mold.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Middle ear mold. 874.3430 Section 874.3430 Food and...Prosthetic Devices § 874.3430 Middle ear mold. (a) Identification. A middle ear mold is a preformed device that is...

2010-04-01

176

The ear and its malformations: strange beliefs and misconceptions  

Microsoft Academic Search

Objective. To explore the strange beliefs and misconceptions related to the ear and its malformations, and how these have changed from ancient times until today.Methods. Ancient documents, journal articles, and history books were studied to research ancient and current beliefs and misconceptions with regard to the ear and its malformations.Results. The ear has been the centre of various beliefs and

Irene E Gamatsi; Thomas P Nikolopoulos; Dimitra E Lioumi

2003-01-01

177

Fly Ear Inspired Miniature Acoustic Sensors for Detection and Localization.  

National Technical Information Service (NTIS)

Inspired by the micro-scale ears of the fly Ormia, which show remarkable sound localization ability, the overall objective of this project is to achieve a further understanding of the mechanism the fly ear and use this understanding to develop Fly-Ear Ins...

M. Yu

2011-01-01

178

Factors contributing to bone conduction: The outer ear  

NASA Astrophysics Data System (ADS)

The ear canal sound pressure and the malleus umbo velocity with bone conduction (BC) stimulation were measured in nine ears from five cadaver heads in the frequency range 0.1 to 10 kHz. The measurements were conducted with both open and occluded ear canals, before and after resection of the lower jaw, in a canal with the cartilage and soft tissues removed, and with the tympanic membrane (TM) removed. The sound pressure was about 10 dB greater in an intact ear canal than when the cartilage part of the canal had been removed. The occlusion effect was close to 20 dB for the low frequencies in an intact ear canal; this effect diminished with sectioning of the canal. At higher frequencies, the resonance properties of the ear canal determined the effect of occluding the ear canal. Sectioning of the lower jaw did not significantly alter the sound pressure in the ear canal. The sound radiated from the TM into the ear canal was investigated in four temporal bone specimens; this sound is significantly lower than the sound pressure in an intact ear canal with BC stimulation. The malleus umbo velocity with air conduction stimulation was investigated in nine temporal bone specimens and compared with the umbo velocity obtained with BC stimulation in the cadaver heads. The results show that for a normal open ear canal, the sound pressure in the ear canal with BC stimulation is not significant for BC hearing. At threshold levels and for frequencies below 2 kHz, the sound in the ear canal caused by BC stimulation is about 10 dB lower than air conduction hearing thresholds; this difference increases at higher frequencies. However, with the ear canal occluded, BC hearing is dominated by the sound pressure in the outer ear canal for frequencies between 0.4 and 1.2 kHz.

Stenfelt, Stefan; Wild, Timothy; Hato, Naohito; Goode, Richard L.

2003-02-01

179

Evidence for, and taxonomic value of, an arachidonic acid cascade in the Lipomycetaceae.  

PubMed

By using specific inhibitors of the lipoxygenase and cyclo-oxygenase pathways, arachidonic acid metabolites with similar sensitivities towards these inhibitors as in humans, were detected in Dipodascopsis uninucleata. The taxonomic value of aspirin sensitive arachidonic acid metabolites in the Lipomycetaceae was next assessed. No metabolites of which the production is inhibited by aspirin were detected in strains representing the following species: Lipomyces starkeyi, Lipomyces kononenkoae, Lipomyces tetrasporus, Myxozyma melibiosi, Myxozyma mucilagina, Myxozyma kluyveri, Waltomyces lipofer, Zygozyma oligophaga and Zygozyma arxii. The detection of such aspirin sensitive arachidonic acid metabolites in representative strains of Lipomyces anomalus and the genus Dipodascopsis, emphasises the isolated position of these taxa in the genus Lipomyces and the family Lipomycetaceae, respectively. Finally using long chain fatty acid analyses, electrophoretic karyotyping and other phenotypic characters, a phylogenetic scheme is proposed for some genera in the Lipomycetaceae. PMID:1285641

Kock, J L; Coetzee, D J; van Dyk, M S; Truscott, M; Botha, A; Augustyn, O P

1992-11-01

180

The effect of cigarette smoke on the metabolism of arachidonic acid in isolated hamster lungs  

SciTech Connect

The effects of cigarette smoke on the metabolism of exogenous arachidonic acid (AA) were investigated in isolated hamster lungs. Arachidonate was injected into the pulmonary circulation and the metabolites were analysed from the nonrecirculating perfusion effluent by thin layer chromatography. After the pulmonary injection of 66 nmol of 14C-AA about 20% of the injected radioactivity appeared in the perfusion effluent mostly as metabolites in six minutes. When isolated lungs were ventilated with cigarette smoke during the perfusion, the amounts of PGF2 alpha, PGE2 and two unidentified metabolite groups increased in the lung effluent. In two other experimental series hamsters were exposed to cigarette smoke before the lung perfusion either once for 30 min or during one hour daily for ten consecutive days. Neither pre-exposures caused any changes in the amounts of arachidonate metabolites in the lung effluent.

Maennistoe, J.; Toivonen, H.; Hartiala, J.; Bakhle, Y.S.; Uotila, P.

1981-01-01

181

Changes in arachidonic acid metabolism in UV-irradiated hairless mouse skin  

SciTech Connect

This study was conducted to investigate the metabolism of arachidonic acid in the skin of hairless mice exposed to UVA, PUVA, UVB, and UVC irradiation. The main products of arachidonic acid in the epidermis were hydroxyeicosatetraenoic acid (HETE), PGE2, and PGD2. Dermis displayed a lower lipoxygenase activity (expressed as HETE production) than the epidermis and showed no detectable cyclooxygenase activity, i.e., no prostaglandin production. The main changes observed in UV-induced inflammatory reactions were as follows. 1. A 5-fold increase in dermal HETE production in PUVA-treated animals and a 29% reduction in epidermal HETE formation after UVC treatment. 2. A marked decrease of PGD2 and a marked increase of PGE2 formation due to alterations of PGH2 metabolism in the UVB-treated group; however, cyclooxygenase activity was unchanged. These changes in arachidonic acid metabolism in the skin may be of pathophysiologic importance in UV-induced inflammatory reaction.

Ruzicka, T.; Walter, J.F.; Printz, M.P.

1983-10-01

182

Effect of progesterone on the release of arachidonic acid from human endometrial cells stimulated by histamine  

SciTech Connect

Progesterone at concentrations of 10(-7)M and 10(-8)M inhibits release of (/sup 3/H)-arachidonic acid from stimulated, perfused, endometrial cells. The effect is independent of the mechanism of stimulation. Cortisol (10(-5)M but not 10(-7)M) has a similar effect in this system but estradiol (10(-7)M) is without effect. There was a positive correlation (p less than 0.05) between the magnitude of inhibition by progesterone and the day of cycle. The inhibitory action of progesterone on the release of arachidonic acid was greater in endometrial cells than in decidual cells and was apparent after fifteen minutes. The activities of commercial and endometrial cell-free preparations of phospholipase A2 and phospholipase C were unaffected by the presence of progesterone. We conclude that progesterone modulates release of (/sup 3/H)-arachidonic acid from endometrial cells by a rapid, indirect action on phospholipase activity.

Wilson, T.; Liggins, G.C.; Aimer, G.P.; Watkins, E.J.

1986-02-01

183

The essentiality of arachidonic acid and docosahexaenoic acid  

PubMed Central

Objective The purpose of this review is to correlate the clinical finding that patients receiving parenteral nutrition with a fish oil-based lipid emulsion do not develop essential fatty acid deficiency (EFAD) with an experimental murine model, thus showing that arachidonic acid (AA) and docosahexaenoic acid (DHA) are likely to be the essential fatty acids. Background Conventional belief is that linoleic acid (LA, omega-6) and alpha-linolenic acid (ALA, omega-3) are the essential fatty acids (EFAs). We have shown that a fish oil-based lipid emulsion containing AA (omega-6) and docosahexaenoic acid (DHA, omega-3) and insignificant quantities of LA and ALA is efficacious in the treatment of parenteral nutrition-associated liver disease (PNALD), a major cause of liver-related morbidity and mortality. The prospect of using a fish oil-based lipid emulsion as monotherapy has raised concerns of EFAD development, hindering its adoption into clinical practice. Design Data from patients in our institution who received PN with a fish oil-based lipid emulsion was reviewed for clinical and biochemical evidence of EFAD, defined as an elevated triene-tetraene ratio (Mead acid/AA >0.2). We also investigated the minimum amount of fish oil required to prevent EFAD in a murine model and determined whether DHA and AA alone can prevent EFAD. Results No patients receiving PN with a fish oil-based lipid emulsion in our institution have developed biochemical or clinical evidence of EFAD such as an elevated triene-tetraene ratio, growth retardation or dermatitis. This observation parallels our previously published animal studies, which demonstrated prevention of EFAD when thirteen percent of total calories were from fish oil. Moreover, current work in our laboratory shows that AA and DHA provision alone is sufficient to prevent biochemical and physiologic evidence of EFAD in a murine model. Conclusions When dosed appropriately, fish oil-based lipid emulsions contain sufficient EFAs to prevent EFAD. Furthermore, AA and DHA alone may be the true EFAs.

Le, Hau D.; Meisel, Jonathan A.; de Meijer, Vincent E.; Gura, Kathleen M.; Puder, Mark

2012-01-01

184

Protein kinase C, arachidonate metabolism, and tracheal smooth muscle - effects of temperature  

SciTech Connect

Cooling causes airway obstruction in asthma. Contractions of airway smooth muscle may be produced through the phosphatidylinositol cycle and the activation of protein kinase C. Protein kinase C can be activated directly with phorbol esters. The authors studied the effects of temperature on responses to phorbol 12,13-diacetate (PDA) in guinea pig tracheal rings bathed in Krebs-Henseleit solution. At 37/sup 0/C, 1 ..mu..M PDA relaxed the tissue (tension fell 0.60 +/- S.E. 0.04 g). At 27/sub 0/C, 1 ..mu..M PDA contracted the tissue (tension rose 0.050 +/- 0.05 g). In comparison, near maximum contractions produced by 4 ..mu..M carbachol were 2.00 +/- 0.09 g at 37/sub 0/C and 1.90 +/- 0.09 g at 27/sup 0/C. Butler-Gralla et al. showed that phorbol esters may stimulate the release of arachidonic acid from cultured cells. In order to determine whether arachidonate metabolites play a role in responses observed in guinea pig trachea, the authors used indomethacin (a cyclooxygenase inhibitor), FPL 55712 (a leukotriene receptor antagonist) and Na arachidonate. At 37/sup 0/C, 3 ..mu..M indomethacin pretreatment abolished relaxationby 1 uM PDA. At 27/sup 0/C, 10 uM FPL 55712 pretreatment abolished contractions by 1 ..mu..M PDA. Like PDA, 1 ..mu..M Na arachidonate produced relaxation at 37/sup 0/C and contraction at 27/sup 0/C. The authors conclude that the effects of PDA at different temperatures parallel the effects of Na arachidonate. These results suggest that the effects of PDA in the guinea pig trachea are related to the release of endogenous arachidonic acid and that the cyclooxygenase pathway predominates at high temperature and the lipoxygenase pathway predominates at low temperature.

Huang, C.; Baraban, J.; Menkes, H.

1986-03-01

185

Neuroprotective effect of N-acetylcysteine in neurons exposed to arachidonic acid during simulated ischemia in vitro.  

PubMed

The aim of the study was to assess neuroprotective effects of N-acetylcysteine (NAC; 100-200 microM) on cultured cortical neurons exposed to arachidonic acid (AA, 10 microM) during ischemia (oxygen-glucose deprivation). Ischemic conditions decreased neuron viability to 41-47% of normoxic controls; co-exposure with arachidonic acid further attenuated neuron viability to 36.73% after 24 h. Separate exposure to arachidonic acid in normoxia or to ischemic conditions only, increased the number of apoptotic nuclei to 33.56% or 36.78%, respectively. Combined exposure to arachidonic acid and ischemia increased apoptosis frequency to 62.20%. NAC (200 microM) decreased the number of apoptotic nuclei in normoxia in control and arachidonic acid exposed cells. NAC also decreased apoptosis frequency in ischemia to 14%. In neurons exposed to arachidonic acid and ischemic conditions, 100 and 200 microM NAC reduced apoptosis to 24.99% and 19.48%, respectively. NAC provided protection to neurons from toxicity due to arachidonic acid, ischemia and exposure to arachidonic acid in ischemic conditions. PMID:19815959

Pawlas, Natalia; Ma?ecki, Andrzej

2009-01-01

186

Gotch ear in a goat: a case report.  

PubMed

A 1-year-old castrated male Saanen goat was observed to have drooping and edema of the left ear consistent with published accounts of gotch ear in cattle associated with a tick bite. The goat's left ear was edematous from the tip of the pinna to the base of the ear. No signs of trauma or infectious processes were observed. Three engorged Gulf Coast ticks (Amblyomma maculatum) were observed attached inside the ear. Ticks were removed and the ear biopsied at tick attachment sites. The affected ear was treated topically with betadine after removal of the ticks. No other treatment was administered. The goat remained free of clinical signs and the edema of the ear resolved within 3 days after tick removal. No clinical adverse effects of the condition were evident. All three ticks were positive for spotted fever group rickettsia by polymerase chain reaction analysis and showed 100% similarity with the homologous sequence of Rickettsia parkeri. There was no immunohistochemical evidence of spotted fever group rickettsia in the ear samples, supporting the hypothesis that gotch ear is not due to rickettsial infection. This report represents the first apparent case of gotch ear in a goat. PMID:21395411

Edwards, Kristine T; Varela-Stokes, Andrea S; Paddock, Christopher D; Goddard, Jerome

2011-08-01

187

Effects of sulfonylurea agents on platelet arachidonic acid metabolism; study on platelet homogenates.  

PubMed

Effects of three sulfonylurea agents on arachidonic acid metabolism of platelet homogenates were evaluated using HPLC. Gliclazide had no significant inhibitory effects on arachidonic acid metabolism. Glibenclamide and glimepiride both inhibited the production of cyclooxygenase-related metabolites, thromboxane B2 (TXB2) and 12-hydroxy 5,8,10-heptadecatrienoic acid (HHT), whereas 12-hydroxy 5,8,10,14-eicosatetraenoic acid (12-HETE), a 12-lipoxygenase-related product, was unaffected. These findings confirmed part of our previous report using intact platelets, except that we found in the present study that glibenclamide had no inhibitory effect on 12-lipoxygenase. PMID:8093094

Satoh, K; Ozaki, Y; Yatomi, Y; Kume, S

1994-08-30

188

The effect of fluid mechanical stress on cellular arachidonic acid metabolism  

NASA Technical Reports Server (NTRS)

The effect of sublytic levels of mechanical perturations of cells on cell metabolism were investigated by analyzing the products of arachidonic acid (used as a marker metabolite) in blood platelets, polymorphonuclear leucocytes, and cultured umbilical-vein endothelial cells after the suspensions of these cells were subjected to a shear stress in a modified viscometer. It is shown that the sublytic levels of mechanical stress stimulated the arachidonic acid metabolism in all these cell types. Possible biological implications of this stress-metabolism coupling are discussed.

Mcintire, L. V.; Frangos, J. A.; Rhee, B. G.; Eskin, S. G.; Hall, E. R.

1987-01-01

189

Structures that Contribute to Middle-Ear Admittance in Chinchilla  

PubMed Central

We describe measurements of middle-ear input admittance in chinchillas (Chinchilla lanigera) before and after various manipulations that define the contributions of different middle-ear components to function. The chinchilla’s middle-ear air spaces have a large effect on the low-frequency compliance of the middle ear, and removing the influences of these spaces reveals a highly admittant tympanic membrane and ossicular chain. Measurements of the admittance of the air spaces reveal that the high-degree of segmentation of these spaces has only a small effect on the admittance. Draining the cochlea further increases the middle-ear admittance at low frequencies and removes a low-frequency (less than 300 Hz) level dependence in the admittance. Spontaneous or sound-driven contractions of the middle-ear muscles in deeply anesthetized animals were associated with significant changes in middle-ear admittance.

Rosowski, John J.; Ravicz, Michael E.; Songer, Jocelyn E.

2009-01-01

190

Applied comparative anatomy of the avian middle ear.  

PubMed Central

The anatomy of the middle ear has been studied in nine species of birds, with particular reference to the structure of the ossicle and its relationship to the tympanic membrane. The morphology of the avian middle ear has been compared to that of the reconstructed human middle ear. Drum to stapes foot plate assemblies created during ossiculoplasty operations differ from the pattern found in the avian middle ear in a number of important respects and this may help to explain why they are often unsuccessful. It is not technically feasible to reproduce the avian middle ear pattern exactly in the human middle ear and developments in reconstructive technique should therefore be directed towards reproducing the three ossicle pattern of the mammalian ear. Images Figure 1. Figure 2.

Mills, R

1994-01-01

191

Analysis of OH Bolted Ear Connection  

SciTech Connect

The D0 endcap calorimeter outer hadronic (OH) modules play a major structural role in the calorimeter assembly. The disrete modules, once connected together, form a ring within which other massive calorimetry will reside. It has been proposed that the connection of the OH at the downstream end be accomplished by extending the downstream endplates in the radial direction to form 'ears', and then through-bolting between adjacent ears as shown in Fig. 1. A single 2 1/4 in. dia. bolt is used, and previous calculations have determined that the design load on this joint should be 130,000 lbs tension. The high load and serious consequences of failure make this a critical component in the calorimeter assembly. The purpose of this analysis is to investigate the stresses in the connection and other mechanical characteristics which determine joint performance.

Wands, Bob; /Fermilab

1987-12-30

192

Why Do Elephants Flap Their Ears?  

NASA Astrophysics Data System (ADS)

It is estimated that a 4200 kg elephant generates as much as 5.12 kW of heat. How the elephant dissipates its metabolic heat and regulates its body temperature has been investigated during the past seven decades. Findings and conclusions differ sharply. The high rate of metabolic heat coupled with low surface area to volume ratio and the absence of sweat glands eliminate surface convection as the primary mechanism for heat removal. Noting that the elephant ears have high surface area to volume ratio and an extensive vascular network, ear flapping is thought to be the principal thermoregulatory mechanism. A computational and experimental program is carried out to examine flow and heat transfer characteristics. The ear is modeled as a uniformly heated oscillating rectangular plate. Our computational work involves a three-dimensional time dependent CFD code with heat transfer capabilities to obtain predictions of the flow field and surface temperature distributions. This information was used to design an experimental setup with a uniformly heated plate of size 0.2m x 0.3m oscillating at 1.6 cycles per second. Results show that surface temperature increases and reaches a steady periodic oscillation after a period of transient oscillation. The role of the vortices shed off the plate in heat transfer enhancement will be discussed.

Koffi, Moise; Jiji, Latif; Andreopoulos, Yiannis

2009-11-01

193

An investigation of ear necrosis in pigs  

PubMed Central

Porcine ear necrosis was investigated in 23 conveniently chosen farms, consisting of 14 case farms and 9 control farms. Biopsies of lesions and oral swabs from pigs on 11 case farms were examined by histology and bacterial culture. All farms were visited for observations and a survey on management, housing, and the presence of other clinical signs or behavioral vices. Histological examination revealed that the lesions began on the surface and progressed to deeper layers, and that vascular damage did not appear to be the initiating cause. Spirochetes were only rarely observed in histological examination and were not cultured from biopsies and oral swabs. Staphylococcus aureus and Staphylococcus hyicus were cultured from 91% and 66% of samples, respectively. Ear biting and a humid environment were associated with ear necrosis. On some farms large numbers of pigs were affected and lesions were sometimes extensive. The condition appears to be an infectious disease beginning on the surface of the skin; contributing environmental and management factors are likely.

Park, Jeonghwa; Friendship, Robert M.; Poljak, Zvonimir; DeLay, Josepha; Slavic, Durda; Dewey, Catherine E.

2013-01-01

194

Pursed lips breathing training using ear oximetry.  

PubMed

Pursed lips breathing (PLB) training is often used in the management of patients with chronic obstructive lung disease (COLD). Previous clinical studies have demonstrated that PLB improves arterial oxygen saturation (SaO2) and CO2 removal as well as relieving dyspnea. Twelve hypoxemic subjects with stable COLD were randomly assigned to either the pursed lips (P) or control group consisting of general relaxation (R). The SaO2 was monitored via ear oximetry, and respiratory rate and tidal volume were monitored using a strain gage transducer and the minute volume was calculated. The PLB was taught by an experienced instructor using the ear oximeter as a monitoring display with a goal toward increasing SaO2. The subject was taught general relaxation (Rlx) with the aid of pleasant music. We compared PLB and Rlx treatments using an A-B-A crossover study design. In both groups, PLB significantly improved SaO2 over baseline (p less than 0.001) whereas Rlx did not. We conclude that patients can learn to increase their SaO2 by PLB using ear oximetry adjunctively. PMID:3731893

Tiep, B L; Burns, M; Kao, D; Madison, R; Herrera, J

1986-08-01

195

The glue ear 'epidemic': a historical perspective.  

PubMed

This paper explores the historical context of the dramatic rise in surgery for glue ear in the mid-20th century, and questions the published assertion that this represented a manufactured 'epidemic'. In examining historical sources, the reader's theoretical viewpoint greatly influences their conclusions: the sustained rise in treatment for glue ear may be seen as the advance of science in a golden age or the resistance of insular professionals to reason in the light of new scientific study methods. Current views on the practice of medicine, consumerism, science and standardisation, rationing and the nature of 'truth' all affect the way that we see this period. Technological advances clearly allowed better diagnosis and more effective treatment, but these did not appear to drive an 'epidemic', rather they were developed to meet the pre-existing challenges of otological practice. The proposition that an 'epidemic' was created does not appear to have any solid grounding. Society's perception of what constitutes disease and what needs treatment may have evolved, but the prevalence of other important diseases changed dramatically over this time period, and a real change in the epidemiology of glue ear cannot be dismissed. In defining the case for and against surgical treatment, a solely positivist, quantitative worldview cannot give us a complete picture of benefit and risk to individuals, families and society at large. PMID:21653931

Alderson, David

2011-12-01

196

Outer ear temperature and time of death.  

PubMed

From a research sample of 138 corpses, divided into four subgroups of ambient storage temperature (0-5 degrees C, 6-10 degrees C, 11-15 degrees C and 16-23 degrees C) four linear regression formulae of actual versus estimated post-mortem interval were obtained ('interval' formulae) using a single outer ear temperature measurement on both sides. This method showed the best correlation coefficient among five other methods previously proposed for time of death determination (rectal temperature, vitreous K+, CSF K+, blood log NA+/K+ and log Cl-), however its results were less accurate than those obtained with a multivariate equation combining several of the above mentioned methods. Eventually an equation expressing time of death (TOD) as a function of outer ear temperature (OE T degrees) and ambient temperature was also established from the whole research sample ('global' formulae). On a different sample of 141 corpses the regression formulae ('interval' and 'global') for the outer ear temperature were compared to three methods based on a single rectal temperature measurement ('rule of thumb' 1 and 2, Henssge nomogram) and therefore useful at the scene; the results of all methods were compared within the four subgroups of ambient temperature as well as in three subgroups of different post-mortem interval lengths (< 7 h, < 10 h, < 15 h). In all cases the outer ear temperature formulae provided better results than the rectal temperature methods (especially Henssge nomogram and rule of thumb 1). Moreover they did not show any post-mortem plateau which was present in almost 30% of cases when rectal temperature was measured in corpses kept at ambient temperature above 15 degrees C. Our results show that outer ear temperature measurement is the method which provides the best simplicity/quality ratio and should therefore be proposed for use at the scene when conditions are similar to those of our experiment (within buildings). A software equipped thermometer is required in order to use in each case the appropriate formula and confidence interval. PMID:9022275

Baccino, E; De Saint Martin, L; Schuliar, Y; Guilloteau, P; Le Rhun, M; Morin, J F; Leglise, D; Amice, J

1996-12-01

197

[Materials for reconstruction of the middle ear].  

PubMed

To rehabilitate most cases of conductive hearing loss closure of ear drum perforations and rebuilding of the ossicular chain can be performed. Due to the great number of biocompatible bone substitute materials available it is occasionally difficult for the surgeon to choose the most favorable substitute. Autogenous structures (ossicles, cortical bone, cartilage) and allogenous tissues (ossicles, cortical bone, cartilage, dentin) are possible bone replacement materials. Xenogenic tissue is currently not used in middle ear surgery. Ionomer cement is a hybrid material for replacement of bone but does not fit direct classification of the various classes of alloplastic materials in current use: that is, metals (gold, steel wire, platinum, titanium), plastics (polyethylene, polytetrafluorethylene) and ceramics (ceramic oxide, carbon, calcium-phosphate ceramic, vitreous ceramic). For restoration of the sound conductive apparatus preference is given to autogenous ossicles because cortical bone is resorbed and cartilage weakens over time. Most surgeons do not use allogenous tissue, because of the possible transmission of such infectious disease as immunodeficiency syndrome or Creutzfeldt-Jakob disease. Only dentin deserves special attention as a possible bone substitute in the middle ear because its form can be preserved during sterilization. Based on the observations available to date, it becomes apparent that titanium implants hold greater promise than gold. Form-stable synthetic materials are not generally recommended due to foreign body reactions which have been confirmed by many investigators. Ceramic materials (e.g. ceramic oxide, carbon, calcium-phosphate ceramic, glass ceramic) are well tolerated in the middle ear and have also proved to be useful over time. Hybrid bone substitute ionomer cement is easily workable and well integrated, showing a good functional outcome. For many years good results in otosclerosis surgery have been achieved with a prosthesis made of platinum-wire and Teflon. Short-term follow-up periods hold great promise with pistons made of gold. Autogenous ossicles, ionomer cement and recently titanium protheses--as far as usable--are employed by the author for reconstructing the middle ear. For the time being platinum-Teflon prostheses and gold are used in otosclerosis surgery. PMID:10197273

Geyer, G

1999-02-01

198

Nicotinic acid-induced flushing is mediated by activation of epidermal langerhans cells  

Microsoft Academic Search

The antidyslipidemic drug nicotinic acid (niacin) has been used for decades. One of the major problems of the therapeutical use of nicotinic acid is a strong cutaneous vasodilation called flushing, which develops in almost every patient taking nicotinic acid. Nicotinic acid-induced flushing has been shown to be mediated by the nicotinic acid receptor GPR109A and to involve the formation of

Z. Benyo; A. Gille; C. L. Bennett; B. E. Clausen; S. Offermanns

2006-01-01

199

Antioxidant properties of methanolic extracts from several ear mushrooms.  

PubMed

Five kinds of ear mushrooms are commercially available in Taiwan, including black, red, jin, snow, and silver ears. Methanolic extracts were prepared from these ear mushrooms, and their antioxidant properties were studied. For all methanolic extracts from ear mushrooms, the antioxidant activities in the 1,3-diethyl-2-thiobarbituric acid method were moderate (38.6 approximately 74.6%) at 1.0-5.0 mg/mL. Methanolic extracts from red, jin, and snow ears showed excellent antioxidant activities in the conjugated diene method at 5.0 mg/mL. At 5.0 mg/mL, reducing powers of methanolic extracts were in the descending order of snow > black approximately red approximately jin > silver ears. The scavenging effect of methanolic extracts from ear mushrooms on 1,1-diphenyl-2-picrylhydrazyl radicals was excellent except for that from silver ears. Ear mushroom extracts were not good scavengers for hydroxyl free radicals but were good chelators for ferrous ions. Naturally occurring antioxidants, including ascorbic acid, tocopherols, and total phenols, were found in the methanolic extracts. However, beta-carotene was not detected. Total antioxidant components were 15.69, 30.09, 27.83, 49.17, and 31.70 mg/g for black, red, jin, snow, and silver ears, respectively. PMID:11714344

Mau, J L; Chao, G R; Wu, K T

2001-11-01

200

Arachidonic acid metabolism as a reporter of skin irritancy and target of cancer chemoprevention  

Microsoft Academic Search

Keratinocytes respond to skin irritation and injury by cytokine release and a rapid but transient activation of arachidonic acid metabolism along both the cyclooxygenase and lipoxygenase pathways. In the first part of this article results are reviewed indicating that the release of pro-inflammatory mediators such as eicosanoids and interleukin-1 from keratinocytes provides a suitable in vitro parameter of irritancy. Based

F. Marks; G. Fürstenberger; K. Müller-Decker

1998-01-01

201

Uptake and utilization of arachidonic acid in infective larvae of Angiostrongylus cantonensis.  

PubMed

Infective larvae of Angiostrongylus cantonensis may take up and incorporate exogenous arachidonic acid into their lipid pool. By scintillation counting, uptake and incorporation were determined to be time dependent. Arachidonic acid was mainly incorporated into phospholipid (56.8%) and neutral lipid (22.4%) pools. In the neutral lipids, 64.0% was diglyceride and 36.0% triglyceride. Phosphatidylcholine was the predominant fatty acid in the phospholipid pool. In addition to the release of leukotriene B4, the parasite was found to generate radiolabelled CO2 after incubation with [U-14C]arachidonate. Moreover, enzymatic analysis of crude extracts revealed the presence of acyl-CoA dehydrogenase (short and long chain), thiolase, enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase. These findings suggest that infective larvae of A. cantonensis not only take up and incorporate exogenous arachidonic acid into their lipid pool, but may also utilize the fatty acid through a functional ?-oxidation pathway. PMID:21106133

Tang, P; Wang, L-C

2011-12-01

202

Techniques for delivery of arachidonic acid to Pacific oyster, Crassostrea gigas, spat: a preliminary investigation  

Microsoft Academic Search

The present study tested two techniques for dietary supplementation of Crassostrea gigas spat with PUFA, such as arachidonic acid (AA). The first technique consisted of a preliminary enrichment and growth of an algal concentrate (T-ISO, Isochrysis sp.) with AA dissolved in an ethanol solution, the whole culture then being fed to the spat. This enrichment increased the AA weight percentage

C. Seguineau; P. Soudant; J. Moal; M. Delaporte; C. Quéré; J.-F. Samain

2006-01-01

203

Specificity of the ferrous oxidation of xylenol orange assay: analysis of autoxidation products of cholesteryl arachidonate  

Microsoft Academic Search

Autoxidation of polyunsaturated fatty acids and esters leads to a complex mixture containing hydroperoxides and cyclic peroxides. The oxidation mixture of cholesteryl arachidonate, which has been characterized by a variety of mass spectrometry techniques, was subject to analysis by conventional thiobarbituric acid-reactive substance (TBARS) and ferrous oxidation in xylenol orange (FOX) assays. Our results indicate that the FOX assay is

Huiyong Yin; Ned A Porter

2003-01-01

204

Arachidonic acid metabolism in the platelets and neutrophils of diabetic rabbit and human subjects  

Microsoft Academic Search

An alteration of arachidonic acid metabolism to prostaglandins and leukotrienes from platelets and polymorphonuclear leukocytes respectively is evident in subjects with diabetes mellitus. There is evidence of altered platelet\\/vascular wall interactions in diabetes mellitus and evidence that polymorphonuclear leukocytes influence the vascular walls. Theories on the pathogenesis of atherosclerosis include both blood cells. Platelet hypersensitivity is evident in those platelets

Greco

1985-01-01

205

Uptake of arachidonic acid into membrane phospholipids: Effect on chloride transport across cornea  

Microsoft Academic Search

Summary We demonstrate that arachidonic acid (AA) stimulation of chloride transport across frog cornea is mediated via two independent pathways: (1) stimulation of prostaglandins and cAMP synthesis, and (2) a direct physical change in the membrane produced by substitution of different phospholipid acyl chains. AA is well known as a precursor in the synthesis of prostaglandins, which have been shown

Barry E. Schaeffer; Marc S. Kanchuger; Michal Razin; Jose A. Zadunaisky

1982-01-01

206

Effect of oxygen-derived free radicals on arachidonic acid turnover in isolated perfused rat lung  

SciTech Connect

Turnover of arachidonic acid in lung was studied by perfusing an isolated and ventilated rat lung in the presence of (/sup 14/C)-arachidonic acid for 30 min. Oxygen-derived free radicals were generated within the pulmonary circulation by the action of xanthine oxidase (XO) (0.1 ..mu../ml) on hypoxanthine (0.1 ..mu..mol/ml). Lung was also preperfused in the presence or absence of superoxide dismutase (SOD) (5 ..mu..g/ml) and catalase (5 ..mu..g/ml) prior to the addition of radiolabeled arachidonic acid and free radical generating system. After the perfusion was over, several biopsies were obtained and phospholipids were extracted and separated from one of the biopsies. Individual phospholipids were compared with known standards and counted for radioactivity. An appreciable amount of radioactivity was found in total phospholipids and in phosphatidyl choline and phosphatidyl inositol fractions in control lungs. Some radioactivity was also noticed in phosphatidyl ethanolamine fraction. The isotopic incorporation was significantly inhibited when lung was perfused in the presence of hypoxanthine and XO. The incorporation of (/sup 14/C)-radioactivity was restored to the control levels when lung was preperfused with SOD and catalase. These results suggest that oxygen radicals inhibit the arachidonic acid turnover in isolated and perfused rat lung.

Jones, R.; Otani, H.; Das, D.K.

1986-05-01

207

Arachidonic acid release: An in vitro alternative for dermal irritancy testing  

Microsoft Academic Search

Validated in vitro alternatives are being utilized extensively for mutagenicity and ocular irritancy testing. However, validation of alternative assays for dermal irritancy is progressing more slowly. As the irritant response in human skin is mediated, at least in part, by eicosanoids derived from arachidonic acid, the effect of relatively pure anionic surfactants (AS, n = 8) and surfactant-containing finished products

V. A. Deleo; M. P. Carver; J. Hong; K. Fung; B. Kong; S. Desalva

1996-01-01

208

Effects of intravenous and aerosolized arachidonic acid on alveolar epithelial permeability in rabbits.  

PubMed

To determine whether arachidonic acid (AA) alters alveolar epithelial permeability, we studied the effect of both continuous intravenous and aerosolized AA on clearance of [99m]Tc-DTPA from lung to blood in rabbits. Although intravenous AA increased prostacyclin production and aerosolized AA decreased systemic blood pressure, neither continuous intravenous nor aerosolized AA augmented alveolar epithelial permeability. PMID:1905059

Stevenson, J L; Quan, S F; Witten, M L; Hall, J N; Roseberry, H R; McNeill, G C; Lemen, R J

1991-04-01

209

CHEMICAL NATURE AND IMMUNOTOXICOLOGICAL PROPERTIES OF ARACHIDONIC ACID DEGRADATION PRODUCTS FORMED BY EXPOSURE TO OZONE  

EPA Science Inventory

Ozone (O3) exposure in vivo has been reported to degrade arachidonic acid (AA) in the lungs of rodents. The O3-degraded AA products may play a role in the lung responses to this toxicant. In order to study the chemical nature and biological activity of O3-exposed AA, we exposed A...

210

Arachidonic and docosahexanoic acid content of bovine brain myelin: Implications for the pathogenesis of multiple sclerosis  

Microsoft Academic Search

Lipids were extracted from bovine brain myelin using a mixture of hexane and isopropanol (3:2). Myelin lipids were resolved, using Sep Pak chromatography, into four fractions: Fraction 1 contained neutral lipids, fraction 2, free fatty acids, fraction 3, ethanolamine phospholipids and fraction 4, choline phospholipids. Docosahexanoic (DHA) and arachidonic (AA) acids in these fractions were measured by RPHPLC. Fraction 2

Khurshed A. Ansari; Don W. Shoeman

1990-01-01

211

Ozone-induced alterations in arachidonic acid metabolism in cultured lung cell types  

SciTech Connect

One of the most sensitive cells to ozone (O/sub 3/) damage is the pulmonary endothelial cell which may mediate the response of the lung to injury by productions of the autacoid prostacyclin (PGl/sub 2/), a metabolite of arachidonic acid. Exposure of endothelial cell cultures to ozone produced a concentration dependent decreases in the synthesis of PGl/sub 2/. Release of /sup 3/H-arachidonic acid from endothelial cells was increased after two hours of 0.3 and 1.0 ppm O/sub 3/ exposure while incubation of cells with 20 ..mu..M and arachidonate (4 min) after exposure resulted in a decreased PGl/sub 2/ synthesis. Cells exposed to 1.0 ppm O/sub 3/ did not have a decreased PGl/sub 2/ production when incubated with 5 ..mu..M PGH/sub 2/ immediately after exposure. These results are consistent with an O/sub 3/-induced inhibition of cyclooxygenase activity. O/sub 3/ exposure (1.0 ppm) produced a rapid decrease in endothelial PGl/sub 2/ synthesis. The data suggest that cyclooxygenase was not inactivated by increased autooxidation due to metabolism of increased free arachidonate. PGl/sub 2/ synthesis returned to control amounts within 12 hours after ozone exposure similar to the recovery time of irreversibly inhibited cyclooxygenase suggesting that recovery was due to de novo synthesis of enzyme. Lipid peroxides and/or hydrogen peroxide (H/sub 2/O/sub 2/) may have caused the inhibition of cyclooxygenase. Incubation of cells with catalase (5 U/ml) protected against the O/sub 3/-induced depression in PGl/sub 2/ synthesis. Exogenously added H/sub 2/O/sub 2/ (greater than or equal to 75 ..mu..M) caused a stimulation of basal PGl/sub 2/ production but depressed arachidonate-stimulated synthesis. O/sub 3/ exposure (2 hr, 1.0 ppm) produced altered metabolism of arachidonate in other important lung cell types, e.g., a decreased PGl/sub 2/ synthesis in smooth muscle cultures. Exposure of lung macrophages to O/sub 3/ caused an increase in almost all arachidonate metabolites produced.

Madden, M.C.

1986-01-01

212

Inhibitors of arachidonic acid metabolism: effects on rat striatal dopamine release and uptake.  

PubMed

The purpose of this study was to investigate the possibility that arachidonic acid metabolites mediate D-2 dopamine (DA) receptor inhibition of striatal DA release. The phospholipase A2 inhibitor p-bromophenacyl bromide (BPB; 10 microM) increased electrically evoked overflow of endogenous DA from rat striatal slices and appeared to partially block the modulatory effects of the D-2 DA receptor agonist N-0437 on this release. However, BPB also increased spontaneous DA outflow in a dose-dependent manner. U-73122 (10 microM), another phospholipase A2 inhibitor, decreased evoked overflow of DA, did not affect the action of N-0437 but also increased spontaneous outflow of DA. In contrast, arachidonic acid (30 microM) produced no effects. In slices prelabeled with [3H]DA, exposure to BPB, U-73122 and nordihydroguaiaretic acid (a lipoxygenase inhibitor) significantly increased spontaneous outflow of tritium whereas the cyclooxygenase inhibitors aspirin and indomethacin did not. In low micromolar concentrations, BPB, U-73122 and nordihydroguaiaretic acid, but not aspirin and indomethacin, inhibited uptake of [3H]DA into striatal synaptosomes and binding of [3H]mazindol to the DA transporter. Only U-73122 affected D-2 DA receptor binding. Taken together, these results suggest that it is unlikely that arachidonic acid metabolites mediate the actions of release-modulating D-2 DA autoreceptors in the striatum. However, the results also suggest that certain inhibitors of arachidonic acid metabolism are relatively potent DA uptake blockers/releasers and that this action is unrelated to their inhibition of enzymes in the arachidonic acid cascade. Caution should be used when using BPB and nordihydroguaiaretic acid to study mechanisms involved in DA release, because these compounds may increase DA release and thereby appear to antagonize the effects of activation of presynaptic receptors. PMID:1828506

Cass, W A; Larson, G; Fitzpatrick, F A; Zahniser, N R

1991-06-01

213

Phospholipase participation in cannabinoid-induced release of free arachidonic acid.  

PubMed

The exposure of cells in culture to cannabinoids results in a rapid and significant mobilization of phospholipid bound arachidonic acid. In vivo, this effect has been observed as a rise in eicosanoid tissue levels that may account for some of the pharmacological actions of delta 9-tetrahydrocannabinol (THC), the major psychoactive cannabinoid. Fluoroaluminate pretreatment of mouse peritoneal cells potently reduced the cannabinoid response, while promoting arachidonate release on its own, consistent with earlier observations that this effect may be a receptor/G-protein-mediated process. Further support for receptor mediation was the demonstration of saturable, high-affinity cannabinoid binding in these cells. THC potency was reduced in the presence of ethanol, and was accompanied by significant increases in phosphatidylethanol (PdEt) levels, a unique product of phospholipase D (PLD) activity. THC-dependent arachidonate release was reduced partially in similar amounts by either propranolol or wortmannin, further implicating PLD as a mediator of THC action. A central role for diacylglyceride (DAG), a secondary product of PLD metabolism, in this THC-induced process, both as a source of arachidonate and as a stimulator of protein kinase C (PKC), is supported by the data in this report. Cells exposed to phorbol ester for 18 hr prior to THC challenge became less responsive, indicating a possible role for PKC. The involvement of PKC further suggests participation by phospholipase A2 (PLA2) whose activity may be regulated by the former. Treatment of cells with interleukin-1 alpha, an agent known to elevate PLA2 levels, caused an increase in the THC response, supporting a role for this enzyme in the release reaction. Direct evidence, by immunoblotting, for the activation and phosphorylation of PLA2 by THC was also obtained. In summary, the evidence presented in this report indicates that THC-induced arachidonic acid release occurs through a series of events that are consistent with a receptor-mediated process involving the stimulation of one or more phospholipases. PMID:7945419

Burstein, S; Budrow, J; Debatis, M; Hunter, S A; Subramanian, A

1994-09-15

214

Co-administration of acetyl-11-keto-beta-boswellic acid, a specific 5-lipoxygenase inhibitor, potentiates the protective effect of COX-2 inhibitors in kainic acid-induced neurotoxicity in mice.  

PubMed

Cyclooxygenase (COX) and lipoxygenase (LOX) are responsible for the metabolism of arachidonic acid into inflammatory metabolites, prostaglandins and leukotrienes, respectively. The upregulation of these enzymes in the central nervous system has been demonstrated to be responsible for the increased neuronal vulnerability to degeneration. Kainic acid, a glutamate receptor agonist and responsible for neuronal excitotoxicity and oxidative damage via different mechanisms, is capable of stimulating mRNA of both COX-2 and 5-LOX in the brain. The present study was designed to study the effects of COX inhibitors (indomethacin, nimesulide, rofecoxib) and a 5-LOX inhibitor (acetyl-11-keto-beta-boswellic acid; AKBA) and the combination of these inhibitors (dual inhibition) on kainic acid induced excitotoxicity and oxidative and nitrosative damage in mice. The results from the present study indicated that AKBA, indomethacin, and nimesulide per se did not produce any change in the behavioural parameters after kainic acid administration; however, rofecoxib per seproduced a significant increase in the latency of clonic (seizure-like) movement and a decrease in mortality rate as compared with kainic acid treated animals. In combination studies AKBA, rofecoxib, and nimesulide produced a more pronounced effect than either of these drugs alone. Further, the effect of AKBA combined with rofecoxib was significantly more marked when compared with AKBA combined with nimesulide. Besides this, identical results were found for the effect of these agents and their combination against oxidative damage induced by kainic acid. These findings indicate the potential role of COX-2 inhibitors and also their combination with the 5-LOX inhibitor in kainic acid induced excitotoxicity and oxidative damage by virtue of their antioxidant effect and suggest the need for the development of dual inhibitors for the treatment of neuronal excitotoxicity. PMID:17139192

Bishnoi, Mahendra; Patil, C S; Kumar, Anil; Kulkarni, Shrinivas K

2007-01-01

215

Synergy between cyclo-oxygenase-2 induction and arachidonic acid supply in vivo: consequences for nonsteroidal antiinflammatory drug efficacy.  

PubMed

Prostanoids produced via the action of cyclo-oxygenase-2 (COX-2) appear central to many inflammatory conditions. Here we show in LPS-treated rats, however, that COX-2 induction alone does not greatly increase prostanoid production in vivo. For this, a second, arachidonic acid liberating stimulus is also required. Thus, only after intravenous injection of bradykinin or exogenous arachidonic acid was a marked increase in prostanoid formation seen. There is, therefore, synergy between proinflammatory mediators: both induction of COX-2 protein and an increase in the supply of arachidonic acid are required to greatly enhance prostanoid production. Second, we show that supplying arachidonic acid to increase prostanoid production reduces the effectiveness of both currently used nonsteroidal antiinflammatory drugs (NSAIDs) (diclofenac) and novel COX-2-selective inhibitors (NS-398, celecoxib) as inhibitors of COX-2 activity. Our data lead to two important conclusions. First, increased prostanoid production in inflammation is a two-component response: increased COX-2 expression and increased arachidonic acid supply. Second, the supply of arachidonic acid to COX-2 determines the effectiveness of NSAIDs. NSAIDs and selective COX-2 inhibitors, therefore, will generally be less effective at more inflamed sites, providing a rationale for the very high doses of NSAIDs required in human conditions such as rheumatoid arthritis.--Hamilton, L. C., Tomlinson, A. M., Mitchell, J. A., Warner, T. D. Synergy between cyclo-oxygenase-2 induction and arachidonic acid supply in vivo: consequences for nonsteroidal antiinflammatory drug efficacy. PMID:9973312

Hamilton, L C; Mitchell, J A; Tomlinson, A M; Warner, T D

1999-02-01

216

Manual therapy and ear pain: a report of four cases  

PubMed Central

Purpose: To report and discuss four cases of ear pain which were treated successfully with manual therapy. Methods: Report of four cases. Results: Four patients with ear pain were referred for chiropractic consult. They were all treated with a combination of manual therapy and exercise with resolution of their ear symptoms. Conclusions: The mechanism of idiopathic ear pain that may be amenable to manual therapy is not fully known. Further research is needed to investigate the etiology of this disorder and to determine whether manual therapy and exercise are viable options in some patients with idiopathic ear pain. In the meantime, it may be advantageous for otolaryngologists to seek input from physicians skilled in assessment and treatment of the musculoskeletal system in cases ear pain for which an otolarygologic etiology cannot be found.

Murphy, Donald R.; Gay, Charles W.

2011-01-01

217

On hearing with more than one ear: lessons from evolution  

PubMed Central

Although ears capable of detecting airborne sound have arisen repeatedly and independently in different species, most animals that are capable of hearing have a pair of ears. We review the advantages that arise from having two ears and discuss recent research on the similarities and differences in the binaural processing strategies adopted by birds and mammals. We also ask how these different adaptations for binaural and spatial hearing might inform and inspire the development of techniques for future auditory prosthetic devices.

Schnupp, Jan W H; Carr, Catherine E

2011-01-01

218

Bilateral middle ear cholesterol granuloma in familial hypercholesterolemia.  

PubMed

Cholesterol granuloma (CG) is a histologic description of foreign body giant cell formation toward cholesterol crystals. The majority of temporal bone CG is unilateral and most common in the petrous apex. Middle ear CG is usually the result of underlying ear diseases. Primary middle ear CG is very rare. Most reported CG has not been associated with familial hypercholesterolemia (FH). FH, an autosomal dominant disorder, manifests as high levels of serum cholesterol and low density lipoprotein (LDL) cholesterol. We report a rare case of FH and bilateral aggressive primary middle ear CG. This publication has been approved by the IRB, Hospital Alor Setar. PMID:18503863

Masaany, Mansor; Siti, Hashim Sabzah; Nurliza, Idris; Mazita, Ami

2008-06-01

219

Otosclerosis associated with type B-1 inner ear malformation  

PubMed Central

Summary Malformations of bony inner ear are rare anomalies occurring in approximately 20% of patients with congenital sensorineural hearing loss. Conductive hearing loss is usually associated with abnormalities of the external and middle ear. Recent reports of patients with lateral semicircular canal malformations indicate inner ear malformations to be associated with sensorineural or conductive hearing loss. Differential diagnosis of conductive hearing loss should include otosclerosis, isolated ossicular deformities, inner ear anomalies or a combination of these. In this report, a case is described with right vestibule-lateral semicircular canal dysplasia presenting at our centre with bilateral otosclerosis.

De Stefano, A; Dispenza, F; Aggarwal, N; Russo, A

2010-01-01

220

Incorporating anthropometry into design of ear-related products.  

PubMed

To achieve mass customization and collaborative product design, human factors and ergonomics should play a key development role. The purpose of this study was to provide product designers with the anthropometic dimensions of outer ears for different demographic data, including gender and age. The second purpose was to compare the dimensions of various ear-related products (i.e., earphone, bluetooth earphone and ear-cup earphone) with the anthropometic database and recommend appropriate solutions for design. Two hundred subjects aged 20-59 was selected for this study and divided into four age stratifications. Further, three different dimensions of the outer ear (i.e., the earhole length, the ear connection length and the length of the pinna) were measured by superimposed grid photographic technique. The analysis of variance (ANOVA) was used to investigate the effects of gender, and age on ear dimensions. The results showed that all ear dimensions had significant gender effects. A comparison between the anthropometric dimensions and those of current products revealed that most current ear-related products need to be redesigned using anthropometric data. The shapes of earhole and pinna are not circular. Consequently, ear products need to be elongated so that users may feel more comfortably and not have the product slip off easily. PMID:17374520

Liu, Bor-Shong

2008-01-01

221

A case report of meningioma extending to the middle ear  

PubMed Central

Extracranial meningioma with extension into a middle ear is very uncommon. A 74-year-old female was admitted to our hospital with right ear bleeding when removing earwax. In this case, magnetic resonance imaging, computed tomography, her past history and operative findings would consider as infiltrative growth from the right sphenoid ridge meningioma to the right middle ear via the right petrous pyramid and bilateral optic nerve. She underwent only partial extirpation with decompression for optic nerve, rather than total extirpation including middle ear and temporal bone, due to wide invasion of the middle cranial fossa and caversinus sinus.

Kusunoki, Takeshi; Ikeda, Katsuhisa; Miyashita, Mie

2012-01-01

222

A case report of meningioma extending to the middle ear.  

PubMed

Extracranial meningioma with extension into a middle ear is very uncommon. A 74-year-old female was admitted to our hospital with right ear bleeding when removing earwax. In this case, magnetic resonance imaging, computed tomography, her past history and operative findings would consider as infiltrative growth from the right sphenoid ridge meningioma to the right middle ear via the right petrous pyramid and bilateral optic nerve. She underwent only partial extirpation with decompression for optic nerve, rather than total extirpation including middle ear and temporal bone, due to wide invasion of the middle cranial fossa and caversinus sinus. PMID:24765466

Kusunoki, Takeshi; Ikeda, Katsuhisa; Miyashita, Mie

2012-05-29

223

Magnetically driven middle ear ossicles for optical measurement of vibrations in an ear with opened eardrum  

NASA Astrophysics Data System (ADS)

Vibrations of the middle ear ossicles are easily measured by means of laser vibrometry. However, exposing the ossicles requires the removal of the eardrum, with the result that the ossicles can no longer be stimulated acoustically. To overcome this we devised a new set up in which the ossicles can be driven magnetically. After measuring the response of the eardrum to an acoustic signal, we then remove the eardrum and attach a small magnet to the exposed manubrium (the part of the first auditory ossicle, the malleus, which is normally attached to the eardrum). An electromagnetic excitation coil is then used to drive the magnet, and the output to the coil adjusted until the vibration of the manubrium, as measured by the vibrometer, matches that measured in response to the acoustic signal. Such a set-up has uses in research on middle ear mechanics, such as the measurement of non-linearities in their response, as well as applications in the diagnosis of middle ear conditions such as the fixation of the ossicles by otosclerosis, or in chronic otitis media. We describe our set up in which the vibrometer unit is attached to a surgical microscope, offering accurate positioning of the laser beam. We discuss the viability of our method and its future potential by presenting some measurements on artificially fixated ears.

Peacock, John; Unge, Magnus Von; Dirckx, Joris

2012-06-01

224

Diagonal ear-lobe crease: possible significance as cardio-vascular risk factor and its relationship to ear-acupuncture.  

PubMed

The diagonal ear-lobe crease, detectable especially after the age of 40, is still accepted as a sign of coronary heart disease risk. In the literature some authors report an association between anxiety and coronary heart disease. In our work a group of 143 patients with ear-lobe crease showed - in both sexes and in all examined decades (5th, 6th, 7th) - higher levels of anxiety than in the control group. The possible significance of the crease has been considered on the grounds of present knowledge of ear-acupuncture and the somatotopic mapping of CNS on the ear-lobe. PMID:2575346

Romoli, M; Tordini, G; Giommi, A

1989-01-01

225

Vibrations in the human middle ear  

PubMed Central

Summary Background Middle ear surgery techniques can improve hearing destroyed by disease, but results of treatment are difficult to predict. Therefore, researchers use a Laser Doppler Vibrometer to measure vibrations of human middle ear ossicles. Material/Methods Measurements of ossicular chain vibrations are performed on fresh human temporal bone specimens using Laser Doppler Vibrometer. Vibrations of stapes are recorded in 3 cases: 1) for intact ossicular chain, 2) when incus long process is removed, and 3) after long process reconstruction with bone cement. A typical analysis of transfer function is completed by other methods applied in dynamics. Results Measurements and analysis of stapes vibrations in case of intact and damaged ossicular chain show regular and irregular behavior which can be recognize with the help of phase portraits, recurrence plots, correlation dimension, and Hurst and Lyapunov exponents. The long process reconstruction with bone cement gives good results in improving hearing. Conclusions Recurrence plots, and Lyapunov and Hurst exponents used in the study complete information obtained from transfer function and can be employed to enrich the classical approach to ossicular chain vibrations.

Rusinek, Rafal; Szymanski, Marcin; Warminski, Jerzy; Zadrozniak, Marek; Morshed, Kamal

2011-01-01

226

Sp8 regulates inner ear development.  

PubMed

A forward genetic screen of N-ethyl-N-nitrosourea mutagenized Xenopus tropicalis has identified an inner ear mutant named eclipse (ecl). Mutants developed enlarged otic vesicles and various defects of otoconia development; they also showed abnormal circular and inverted swimming patterns. Positional cloning identified specificity protein 8 (sp8), which was previously found to regulate limb and brain development. Two different loss-of-function approaches using transcription activator-like effector nucleases and morpholino oligonucleotides confirmed that the ecl mutant phenotype is caused by down-regulation of sp8. Depletion of sp8 resulted in otic dysmorphogenesis, such as uncompartmentalized and enlarged otic vesicles, epithelial dilation with abnormal sensory end organs. When overexpressed, sp8 was sufficient to induce ectopic otic vesicles possessing sensory hair cells, neurofilament innervation in a thickened sensory epithelium, and otoconia, all of which are found in the endogenous otic vesicle. We propose that sp8 is an important factor for initiation and elaboration of inner ear development. PMID:24722637

Chung, Hyeyoung A; Medina-Ruiz, Sofia; Harland, Richard M

2014-04-29

227

Cauliflower Ear and Skin Infections among Wrestlers in Tehran.  

PubMed

The purpose of the study was to describe the magnitude of the selected sports medicine problems (i.e. cauliflower ear and skin infections) among wrestlers in Tehran. A number of 411 wrestlers were randomly selected from wrestling clubs in Tehran employing cluster sample setting method. The participants were interviewed using a specially designed and validated questionnaire. Nearly half of the participants (44%) had "cauliflower ears". Only 23% of these participants had received any kind of treatment for their acute ear haematomas that are known to result in "cauliflower ears". The prevalence of reported hearing loss among participants with cauliflower ears (11.5%, 95%CI: 6.9 to 16.2) was significantly more than this prevalence among those participants without cauliflower ears (1.8%, 95%CI: 0.1 to 3.5) (p < 0.05). More than half of the participants (52%) had skin infection diagnosed by a physician during the previous year. This study has identified evidence of an increase in hearing loss as a possible side effect of either cauliflower ear or ear injury in wrestling in Iran. There has been an outbreak of ringworm and there is a significant potential for an outbreak of impetigo among wrestlers in Tehran. Key pointsSkin infections are prevalent among wrestlers in Tehran.Commonly wrestlers in Tehran continue to carry out wrestling training while affected by skin infections.Cauliflower ear "is common among wrestlers in Tehran.More research is needed to investigate hearing loss as a possible side effect of either cauliflower ear or ear injury in wrestling in Iran. PMID:24198702

Kordi, Ramin; Mansournai, Mohammad Ali; Nourian, Roh Allah; Wallace, W Angus

2007-01-01

228

Probing the Xenopus laevis inner ear transcriptome for biological function  

PubMed Central

Background The senses of hearing and balance depend upon mechanoreception, a process that originates in the inner ear and shares features across species. Amphibians have been widely used for physiological studies of mechanotransduction by sensory hair cells. In contrast, much less is known of the genetic basis of auditory and vestibular function in this class of animals. Among amphibians, the genus Xenopus is a well-characterized genetic and developmental model that offers unique opportunities for inner ear research because of the amphibian capacity for tissue and organ regeneration. For these reasons, we implemented a functional genomics approach as a means to undertake a large-scale analysis of the Xenopus laevis inner ear transcriptome through microarray analysis. Results Microarray analysis uncovered genes within the X. laevis inner ear transcriptome associated with inner ear function and impairment in other organisms, thereby supporting the inclusion of Xenopus in cross-species genetic studies of the inner ear. The use of gene categories (inner ear tissue; deafness; ion channels; ion transporters; transcription factors) facilitated the assignment of functional significance to probe set identifiers. We enhanced the biological relevance of our microarray data by using a variety of curation approaches to increase the annotation of the Affymetrix GeneChip® Xenopus laevis Genome array. In addition, annotation analysis revealed the prevalence of inner ear transcripts represented by probe set identifiers that lack functional characterization. Conclusions We identified an abundance of targets for genetic analysis of auditory and vestibular function. The orthologues to human genes with known inner ear function and the highly expressed transcripts that lack annotation are particularly interesting candidates for future analyses. We used informatics approaches to impart biologically relevant information to the Xenopus inner ear transcriptome, thereby addressing the impediment imposed by insufficient gene annotation. These findings heighten the relevance of Xenopus as a model organism for genetic investigations of inner ear organogenesis, morphogenesis, and regeneration.

2012-01-01

229

ANTI-INFLAMMATORY ACTIVITY OF PHYCOCYANIN EXTRACT IN ACETIC ACID-INDUCED COLITIS IN RATS  

Microsoft Academic Search

The anti-inflammatory effect of c -phycocyanin extract was studied in acetic acid-induced colitis in rats. Phycocyanin (150, 200 and 300 mg kg?1p.o.) was administered 30 min before induction of colitis with enema of 1 ml of 4% acetic acid per rat. Twenty-four hours later myeloperoxidase (MPO) activity was determined as well as histopathological and ultrastructural studies were carried out in

RICARDO GONZÁLEZ; SANDRA RODRÍGUEZ; ADDYS GONZÁLEZ; DIADELIS REMIREZ; NELSON MERINO

1999-01-01

230

Expression of cytokines and cytokine receptors in the rat brain after kainic acid-induced seizures  

Microsoft Academic Search

We have previously shown that IL-6 protein levels are increased in cerebrospinal fluid in humans after recent tonic–clonic seizures with unchanged levels of IL-1? and TNF?. Here we studied the expression of cytokines IL-6, LIF, IL-1? and TNF? and cytokine receptors IL-6R, LIFR and Gp130 in the rat brain after kainic acid-induced status epilepticus using Northern blot analysis and in

K. A Lehtimäki; J Peltola; E Koskikallio; T Keränen; J Honkaniemi

2003-01-01

231

Benfotiamine attenuates nicotine and uric acid-induced vascular endothelial dysfunction in the rat  

Microsoft Academic Search

The study has been designed to investigate the effect of benfotiamine, a thiamine derivative, in nicotine and uric acid-induced vascular endothelial dysfunction (VED) in rats. Nicotine (2mgkg?1day?1, i.p., 4 weeks) and uric acid (150mgkg?1day?1, i.p., 3 weeks) were administered to produce VED in rats. The development of VED was assessed by employing isolated aortic ring preparation and estimating serum and

Pitchai Balakumar; Ramica Sharma; Manjeet Singh

2008-01-01

232

Growth hormone releasing factor (GRF) increases free arachidonate levels in the pituitary: a role for lipoxygenase products  

SciTech Connect

GRF, a specific stimulator of GH release, increased in a concentration- and time-dependent manner pituitary (/sup 3/H)-arachidonate levels in vitro. This effect was antagonized by 100 nM somatostatin. Exogenous arachidonate also stimulated GH release in vitro. Quinacrine, a phospholipase A2 inhibitor, reduced both basal and GRF-stimulated free arachidonate levels as well as GH release. The cyclooxygenase inhibitor indomethacin was ineffective, while BW755c, which also inhibits the lipoxygenase pathway, produced a further increase in the levels of the fatty acid stimulated by GRF and potently reduced GH release. These results provide additional evidence for the involvement of arachidonate metabolism in the hormone-releasing effect of GRF at the somatotroph. 14 references, 1 figure, 2 tables.

Canonico, P.L.; Speciale, C.; Sortino, M.A.; Cronin, M.J.; MacLeod, R.M.; Scapagnini, U.

1986-01-20

233

Acute exercise increases triglyceride synthesis in skeletal muscle and prevents fatty acid-induced insulin resistance  

PubMed Central

Fatty acid oversupply is a key mediator of skeletal muscle insulin resistance in obesity, primarily via accumulation of fatty acid metabolites and activation of proinflammatory pathways. Herein, we demonstrate that fatty acid–induced insulin resistance in humans is completely prevented the day after 1 session of endurance exercise. Because skeletal muscle is the primary site for systemic glucose disposal and is highly susceptible to impaired insulin action by elevated fatty acid availability, we obtained skeletal muscle samples to investigate possible mechanisms mediating this protective effect of exercise. Prevention of fatty acid–induced insulin resistance after exercise accompanied enhanced skeletal muscle protein expression of key lipogenic enzymes and an increase in muscle triglyceride synthesis. Partitioning more fatty acids toward triglyceride synthesis within muscle reduced the accumulation of fatty acid metabolites and suppressed the proinflammatory response in skeletal muscle, as evidenced by decreased phosphorylation and activation of JNK and increased abundance of inhibitor of NF-?B ? (I?B-?) and I?B-?. We believe this is the first study to demonstrate that 1 session of exercise completely reverses fatty acid–induced insulin resistance in humans. Reversal of insulin resistance accompanied enhanced lipogenic capacity within skeletal muscle, reduced accumulation of highly bioactive fatty acid metabolites, and suppressed activation of proinflammatory pathways known to impair insulin action.

Schenk, Simon; Horowitz, Jeffrey F.

2007-01-01

234

21 CFR 874.3620 - Ear, nose, and throat synthetic polymer material.  

Code of Federal Regulations, 2010 CFR

...Ear, nose, and throat synthetic polymer material. 874.3620 Section...Ear, nose, and throat synthetic polymer material. (a) Identification. Ear, nose, and throat synthetic polymer material is a device...

2010-04-01

235

21 CFR 874.3620 - Ear, nose, and throat synthetic polymer material.  

Code of Federal Regulations, 2010 CFR

...Ear, nose, and throat synthetic polymer material. 874.3620 Section...Ear, nose, and throat synthetic polymer material. (a) Identification. Ear, nose, and throat synthetic polymer material is a device...

2009-04-01

236

Differential diagnosis of throat and ear disease in cats  

Microsoft Academic Search

IN the previous issue, the first of two articles on feline ear, nose and throat disease concentrated on diseases of the nose (In Practice, April 1995, pp 154-161). Here, in the second article, diseases of the throat and ear are covered.

Kim Willoughby; Alison Coutts

1995-01-01

237

Modeling of external ear acoustics for insert headphone usage  

Microsoft Academic Search

Although acoustics of the external ear has been studied extensively for auralization and hearing aids, the acoustic behavior with insert headphones is not as well known. Our research focused on the eects of outer ear physical dimensions, particularly to sound pressure at the eardrum. The main parameter was the length of the canal, but eardrum's damping of resonances was also

Marko Hiipakka; Miikka Tikander; Matti Karjalainen

238

The inner ear of Nazlet Khater 2 (Upper Paleolithic, Egypt)  

Microsoft Academic Search

This paper presents a description and comparison of the Nazlet Khater 2 (NK 2) inner ear structures. This specimen is the only complete modern human skeleton from the earliest Late Stone Age in Africa. The interest in the inner ear structures lies with their strong genetic component. The morphology and biometrical characteristics of the NK 2 bony labyrinth are described

L. Bouchneb; I. Crevecoeur

2009-01-01

239

Dynamics of middle ear prostheses - simulations and measurements.  

PubMed

The efficient and systematic development of a middle ear prosthesis necessitates the use of computer models for the prosthesis itself and the reconstructed middle ear. The structure and parameters of the computer model have to be verified by specific measurements of the implant and the reconstructed ear. To obtain a realistic model of a reconstructed ear, three steps of modeling and measurements have been carried out. To get a first approach of the coupling elements a mechanical test rig representing a simplified reconstructed middle ear was built. The velocity of the stapedial footplate was measured with a laser Doppler vibrometer. The corresponding computer model was formulated, and the respective parameters were determined using the measured dynamical transfer functions. In the second step, a prosthesis was implanted into a human temporal bone without inner ear. Exciting this system with noise, the velocity of the stapes footplate was measured with the laser Doppler vibrometer. Based on the multibody system approach, a mechanical computer model was generated to describe the spatial motions of the reconstructed ossicular chain. Varying some significant parameters, simulations have been carried out. To describe the dynamical behavior of the system consisting of middle and inner ear, the computer model used in the second step has been enlarged by adding a simplified structure of the inner ear. The results were compared with in situ measurements taken from living humans. PMID:10187927

Eiber, A; Freitag, H G; Burkhardt, C; Hemmert, W; Maassen, M; Rodriguez Jorge, J; Zenner, H P

1999-01-01

240

21 CFR 874.4140 - Ear, nose, and throat bur.  

Code of Federal Regulations, 2010 CFR

...4140 Ear, nose, and throat bur. (a) Identification. An ear, nose, and throat bur is a device consisting of...nose, or throat area. The bur consists of a carbide cutting tip on a metal shank or a coating of diamond on a metal shank. The...

2010-04-01

241

21 CFR 874.4140 - Ear, nose, and throat bur.  

Code of Federal Regulations, 2010 CFR

...4140 Ear, nose, and throat bur. (a) Identification. An ear, nose, and throat bur is a device consisting of...nose, or throat area. The bur consists of a carbide cutting tip on a metal shank or a coating of diamond on a metal shank. The...

2009-04-01

242

Middle Ear Pressure: Effects on the Auditory Periphery.  

National Technical Information Service (NTIS)

The effects of direct variation in static middle ear pressure were studied in the acute guinea pig. Pressure differences of from - 500 to + 500 mm of H2O were examined. Pure tones were delivered to the test ear in a closed system and the sound pressure le...

D. L. McPherson J. M. Miller A. Axelsson

1975-01-01

243

Protecting short-term intravascular ear catheters in healthy rabbits  

Microsoft Academic Search

Researchers may place a catheter in the ear vessel of a rabbit for a short period of time in order to collect repeated blood samples without extensive restraint of the animal. Maintaining such a catheter in a healthy rabbit can be challenging, as the animal may scratch at the ear, removing the catheter or forming a large hematoma that might

Rekha N. Orchard; Aphroditi J. Antonopoulos; Donald L. Hamilton; Francesca Sampieri

2012-01-01

244

Alpha Adrenoceptors in the Rabbit Ear Thermoregulatory Microcirculation  

Microsoft Academic Search

The rabbit ear microcirculation was analyzed in a chronic unanesthetized model to evaluate alpha adrenergic microvascular control in a thermoregulatory end organ. This model allowed direct measurement of microcirculatory responses without the effects of anesthetics or inflammatory responses induced by acute surgical intervention. The ipsilateral facial artery was catheterized for drug injections into the experimental ear. Microvascular diameter changes following

Zhongyu Li; L. Andrew Koman; Beth P. Smith; E. Stanley Gordon; Thomas L. Smith

1998-01-01

245

Can you hear me now? Understanding vertebrate middle ear development  

PubMed Central

The middle ear is a composite organ formed from all three germ layers and the neural crest. It provides the link between the outside world and the inner ear, where sound is transduced and routed to the brain for processing. Extensive classical and modern studies have described the complex morphology and origin of the middle ear. Non-mammalian vertebrates have a single ossicle, the columella. Mammals have three functionally equivalent ossicles, designated the malleus, incus and stapes. In this review, I focus on the role of genes known to function in the middle ear. Genetic studies are beginning to unravel the induction and patterning of the multiple middle ear elements including the tympanum, skeletal elements, the air-filled cavity, and the insertion point into the inner ear oval window. Future studies that elucidate the integrated spatio-temporal signaling mechanisms required to pattern the middle ear organ system are needed. The longer-term translational benefits of understanding normal and abnormal ear development will have a direct impact on human health outcomes.

Chapman, Susan Caroline

2010-01-01

246

Medicament contact dermatitis in patients with chronic inflammatory ear disease.  

PubMed Central

Patch testing of 40 patients with chronic inflammatory ear disease demonstrated medicament allergic contact dermatitis in 35%. The most frequent sensitizers were neomycin, framycetin, clioquinol and gentamicin. Although allergic contact dermatitis to dewaxing ear drops was unusual, irritant reactions were common.

Holmes, R C; Johns, A N; Wilkinson, J D; Black, M M; Rycroft, R J

1982-01-01

247

Middle Ear Resonance and Acoustic Immittance Measures in Children.  

ERIC Educational Resources Information Center

This study established a normal middle ear resonance estimated from sweep frequency tympanometry, established normal equivalent ear canal volume, static acoustic admittance, and tympanometric peak pressure at 226 hertz in 90 children with normal hearing and 68 children with deafness, ages 6-15. No significant intergroup or age differences were…

Hanks, Wendy D.; Rose, Katie J.

1993-01-01

248

On the problem of barotrauma of the middle ear  

NASA Technical Reports Server (NTRS)

Pressure damage to the middle ear in 74 cases of pressure trauma was studied. It was found that pressure trauma can be most serious with respect to reducing work capability of personnel in flight, and that pressure trauma of the middle ear developed with acute rhinitis.

Medvezhova, R. A.

1973-01-01

249

Phorbol myristate inhanced specific incorporation of arachidonic acid into phospholipids through lysophospholipid acyltransferase in cultured smooth muscle cells  

Microsoft Academic Search

The effect of stimulation of phospholipase with phorbol 12-myristate 13-acetate and lipopolysaccharide on 1-acyl-glycerophospholipid\\u000a acyltransferase was studied in cultured rabbit aorta smooth muscle cells. The acyltransferase in smooth muscle cells without\\u000a stimulation was active on a wide range of unsaturated fatty acids and was not arachidonic acid specific. Upon increase in\\u000a phospholipase activity, acyltransferase activity only with arachidonic acid as

Tetsuto Kanzaki; Nobuhiro Morisaki; Yasushi Saito; Sho Yoshida

1989-01-01

250

The role of arachidonic acid metabolism in virus-induced alveolar macrophage dysfunction  

SciTech Connect

Alveolar macrophages (AM) recovered from virus-infected lungs have decreased phagocytic, respiratory burst and bactericidal activities. The studies described below investigated the role of eicosanoids in virus induced AM bactericidal dysfunction. The spectrum of eicosanoid metabolites which bovine AM are capable of producing was determined. Cultured AM were exposed to {sup 3}H-arachidonate for 1 hour, stimulated for 4 hours with A23187, phorbol myristate acetate or zymosan and the supernatants extracted and analyzed by HPLC. All stimuli tested caused the release of these cyclooxygenase metabolites: thromboxane B{sub 2}, PGF{sub 2}, PGE{sub 2}, PGD{sub 2} and HHT. The effect of this enhanced release of arachidonate metabolites on the ability of AM to kill bacteria was evaluated. Preincubation with cyclooxygenase inhibitors or dual cyclooxygenase and lipoxygenase inhibitors resulted in partial reversal of the virus-induced bactericidal deficit in PI3 infected AM.

Laegreid, W.W.

1988-01-01

251

Histopathological evidence of protective action of garlic against collagen and arachidonic acid toxicity in rabbits.  

PubMed

Soluble rat tail tendon collagen produced respiratory distress, agitation, convulsions and finally death in rabbits when infused intravenously (i.v.) in lethal doses. Similar observations were noted when a lethal dose of arachidonic acid (unsaturated essential fatty acid) was infused. These agents caused thrombocytopenia, indicative of in vivo platelet aggregation, hypotension and increased levels of thromboxane (TX) B2 (a stable metabolite of TXA2) in the plasma. Histopathological examination of lung, heart and liver tissue indicated that the lungs and livers of treated animals were adversely affected, while heart tissues appeared to be normal. Histopathological examination of lung and liver tissues of animals pretreated with garlic, then treated with a lethal dose of collagen or arachidonic acid showed a significant reduction in the damage observed compared to animals not pretreated with garlic. PMID:1409768

Alnaqeeb, M A; Ali, M; Thomson, M; Khater, S H; Gomes, S A; al-Hassan, J M

1992-08-01

252

Segmentation algorithms for ear image data towards biomechanical studies.  

PubMed

In recent years, the segmentation, i.e. the identification, of ear structures in video-otoscopy, computerised tomography (CT) and magnetic resonance (MR) image data, has gained significant importance in the medical imaging area, particularly those in CT and MR imaging. Segmentation is the fundamental step of any automated technique for supporting the medical diagnosis and, in particular, in biomechanics studies, for building realistic geometric models of ear structures. In this paper, a review of the algorithms used in ear segmentation is presented. The review includes an introduction to the usually biomechanical modelling approaches and also to the common imaging modalities. Afterwards, several segmentation algorithms for ear image data are described, and their specificities and difficulties as well as their advantages and disadvantages are identified and analysed using experimental examples. Finally, the conclusions are presented as well as a discussion about possible trends for future research concerning the ear segmentation. PMID:22994296

Ferreira, Ana; Gentil, Fernanda; Tavares, João Manuel R S

2014-06-01

253

Ear recognition under partial occlusion based on neighborhood preserving embedding  

NASA Astrophysics Data System (ADS)

As a new biometrics authentication technology, ear recognition remains many unresolved problems, one of them is the occlusion problem. This paper deals with ear recognition with partially occluded ear images. Firstly, the whole 2D image is separated to sub-windows. Then, Neighborhood Preserving Embedding is used for feature extraction on each subwindow, and we select the most discriminative sub-windows according to the recognition rate. Thirdly, a multi-matcher fusion approach is used for recognition with partially occluded images. Experiments on the USTB ear image database have illustrated that using only few sub-window can represent the most meaningful region of the ear, and the multimatcher model gets higher recognition rate than using the whole image for recognition.

Yuan, Li; Wang, Zhen-Hua; Mu, Zhi-Chun

2010-04-01

254

Language lateralisation and early right ear deafness: was Wernicke right?  

PubMed Central

The effects of early right ear deafness on lateralisation of auditory language functions are not fully known. A 36 year old right handed man, with a history of perinatal right ear deafness and undergoing evaluation for surgical treatment of seizures that began at age 10 years was studied. Language lateralisation testing by intracarotid sodium amobarbital injection showed receptive and expressive language functions to be strongly lateralised to the left hemisphere. Results with intracarotid sodium amobarbital injection further suggested that transmission of auditory input to the patient's left hemisphere was partially dependent on ipsilateral left ear pathways. Cortical language mapping through implanted subdural electrodes localised auditory language functions to traditional left posterior perisylvian language areas. These results suggest that early right ear deafness does not impede left hemisphere lateralisation and localisation of auditory language functions. Moreover, transmission of auditory information to the patient's left hemisphere seems to be accomplished, in part, by recruitment of ipsilateral left ear pathways.??

Boatman, D.; Krauss, G.

2000-01-01

255

High levels of dietary arachidonic acid triglyceride exhibit no subchronic toxicity in rats  

Microsoft Academic Search

Arachidonic acid (AA), an n?6 long-chain polyunsaturated fatty acid (LC-PUFA), serves an important role in the body as a structural\\u000a fatty acid of many tissues including neurological tissues. It is also a precursor of the n?6 class of eicosanoids and is the\\u000a most abundant n?6 LC-PUFA found in human breast milk. We have optimized the production of a microfungal source

E.-K. Koskelo; K. Boswell; L. Carl; S. Lanoue; C. Kelly; D. Kyle

1997-01-01

256

A new dual inhibitor of arachidonate metabolism isolated from Helichrysum italicum  

Microsoft Academic Search

Six acetophenones (1–6) and one ?-pyrone (7), previously isolated from Helichrysum italicum, were tested for their ability to inhibit enzymatic and non-enzymatic lipid peroxidation, the stable 1,1-diphenyl-2-pycryl-hydrazyl free radical, superoxide scavenging and arachidonic acid metabolism. In addition, they were studied in different experimental models such as the chronic inflammation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA), the phospholipase A2-induced mouse paw oedema

Araceli Sala; M. Carmen Recio; Guillermo R. Schinella; Salvador Máñez; Rosa M. Giner; José-Luis R??os

2003-01-01

257

The role of antioxidants in models of inflammation: Emphasis on l -arginine and arachidonic acid metabolism  

Microsoft Academic Search

Inflammatory processes are made up of a multitude of complex cascades. Under physiological conditions these processes aid\\u000a in tissue repair. However, under pathophysiological environments, such as wound healing and hypoxia-ischaemia (HI), inflammatory\\u000a mediators become imbalanced, resulting in tissue destruction. This review addresses the changes in reactive oxygen species\\u000a (ROS), l-arginine and arachidonic acid metabolism in wound healing and HI and

M. Kapoor; A. N. Clarkson; B. A. Sutherland; I. Appleton

2005-01-01

258

Resistin expression in 3T3-L1 adipocytes is reduced by arachidonic acid  

Microsoft Academic Search

The resistin gene is expressed in adipocytes and encodes a protein proposed to link obesity and type 2 dia- betes. Increased plasma FFA is associated with insulin re- sistance. We examined the effect of separate FFAs on the expression of resistin mRNA in cultured murine 3T3-L1 ad- ipocytes. The FFAs tested did not increase resistin expres- sion, whereas both arachidonic

Fred Haugen; Naeem Zahid; Knut T. Dalen; Kristin Hollung; Hilde I. Nebb; Christian A. Drevon

2004-01-01

259

Techniques for delivery of arachidonic acid to pacific oyster, Crassostrea gigas , spat  

Microsoft Academic Search

The present study tested two techniques for dietary supplementation of Crassostrea gigas spat with PUFA, such as arachidonic acid (AA). The first technique consisted of a preliminary enrichment and growth of an\\u000a algal concentrate (T-ISO, Isochrysis sp.) with AA dissolved in an ethanol solution, the whole culture then being fed to the spat. This enrichment increased the\\u000a AA weight percentage

C. Seguineau; P. Soudant; J. Moal; M. Delaporte; P. Miner; C. Quéré; J.-F. Samain

2005-01-01

260

Characterization of growth and arachidonic acid production of Parietochloris incisa comb. nov (Trebouxiophyceae, Chlorophyta)  

Microsoft Academic Search

Arachidonic acid (AA) is a precursor of biologically activeprostaglandines and leukotrienes. The commercial source for AA at present is afungus, but the recently discovered coccoid green alga,Parietochlorisincisa comb. nov., in which over 90% of total AA is deposited intriacylglycerols, makes this species a potential candidate for commercialproduction of AA. We investigated the effect of the light-regime on cell-AAcontent and on

Zhang Cheng-Wu; Zvi Cohen; Inna Khozin-Goldberg; Amos Richmond

2002-01-01

261

Synthesis of site-specifically deuterated arachidonic acid derivatives containing a remote tritium radiolabel  

PubMed Central

Summary The synthesis of arachidonic acid derivatives containing site-specifically incorporated deuterium atoms and also a remote tritium label are described. Deuterium incorporation at the C11 and/or C15 position was achieved using Wittig chemistry, while the radiolabel was introduced at a remote position using [3H]NaBH4 as the radiolabel source. These compounds can be used to measure secondary kinetic isotope effects for both cyclooxygenase and lipoxygenase enzymes under aerobic turnover with high precision.

McGinley, Chris M.; van der Donk, Wilfred A.

2010-01-01

262

Placental membrane fatty acid-binding protein preferentially binds arachidonic and docosahexaenoic acids  

Microsoft Academic Search

To elucidate further the role of placental membrane fatty acid-binding protein (p-FABPpm) in preferential transfer of maternal plasma long chain polyunsaturated fatty acids (LCPUFA) across the human placenta, direct binding of the purified protein with various radiolabelled fatty acids (docosahexaenoic, arachidonic, linoleic and oleic acids) was investigated. Binding of these fatty acids to the protein revealed that p-FABPpm had higher

Fiona M Campbell; Margaret J Gordon; Asim K Dutta-Roy

1998-01-01

263

Year-round high arachidonic acid levels in herbivorous rabbit fish Siganus fuscescens tissues  

Microsoft Academic Search

To identify a stable resource of 20?4 n?6 (arachidonic acid, AA) in marine fish tissues, the lipid profiles of Siganus fuscescens organs (muscle, liver, and other viscera) and stomach contents were examined throughout the year. Crude total lipid (TL)\\u000a contents in respective organs showed seasonal variations and were high in winter and low in summer. The main FA in TL

Kazufumi Osako; Hiroaki Saito; Koichi Kuwahara; Akira Okamoto

2006-01-01

264

Arachidonic acid released from striatal neurons by joint stimulation of ionotropic and metabotropic quisqualate receptors  

Microsoft Academic Search

ASSOCIATIVE stimulation of N-methyl-D-aspartate (NMDA) receptors and quisqualate ionotropic receptors (Qj) induces long-term potentiation at particular glutamatergic synapses1-7. Release of arachidonic acid as a result of stimulation of NMDA receptors8has been proposed to play a part in the establishment of long-term potentiation9-11. But long-term plasticity events at some other glutamatergic synapses do not involve activation of NMDA receptors11-15. Here we

Aline Dumuis; Jean Philippe Pin; Kiyoshi Oomagari; Michèle Sebben; Joël Bockaert

1990-01-01

265

Interactions of saturated, n-6 and n-3 polyunsaturated fatty acids to modulate arachidonic acid metabolism  

Microsoft Academic Search

Anti-thrombotic effects of omega-3 (n-3) fatty acids are believed to be due to their ability to reduce arachidonic acid levels. Therefore, weanling rats were fed n-3 acids in the form of linseed oil (18:3n-3) or fish oil (containing 20:5n-3 and 22511- 3) in diets containing high levels of either saturated fatty acids (hydrogenated beef tallow) or high levels of linoleic

Manohar L. Garg; Alan B. R. Thomson; Michael T. Clandinin

266

Acute doxorubicin cardiotoxicity alters cardiac cytochrome P450 expression and arachidonic acid metabolism in rats  

Microsoft Academic Search

Doxorubicin (DOX) is a potent anti-neoplastic antibiotic used to treat a variety of malignancies; however, its use is limited by dose-dependent cardiotoxicity. Moreover, there is a strong correlation between cytochrome P450 (CYP)-mediated arachidonic acid metabolites and the pathogenesis of many cardiovascular diseases. Therefore, in the current study, we have investigated the effect of acute DOX toxicity on the expression of

Beshay N. M. Zordoky; Anwar Anwar-Mohamed; Mona E. Aboutabl; Ayman O. S. El-Kadi

2010-01-01

267

Trans-arachidonic acids: new mediators of nitro-oxidative stress.  

PubMed

A reaction of arachidonic acid with the nitrogen dioxide radical (*NO2) or its precursors (peroxynitrite, nitrous acid, nitrogen trioxide) generates a group of nitro lipids named nitroeicosanoids. A distinct feature of this reaction is abundant formation of four trans isomers of arachidonic acid (TAA) via reversible addition of the NO2 radical to the arachidonic acid cis double bonds. This cis-trans isomerization is biologically relevant because many pathologies that involve NO formation such as inflammation, hyperoxia, hypercapnia or exposure to cigarette smoke increase the TAA levels in cells, tissues and in the systemic circulation. Inflammatory conditions have been known to stimulate formation of a variety of oxidized lipids from unsaturated fatty acid precursors via lipid peroxidation mechanisms; however, nitration-dependent cis-trans-isomerization of arachidonic acid is a characteristic process for *NO2. TAA are likely to function as specific and selective biomarkers of the pathologic conditions that define nitro-oxidative stress. Diet independent biosynthesis of trans fatty acids as a result of disease is our new observation. In the past, experimental feeding and clinical studies have supported the concerns that dietary trans fatty acids are cardiovascular risk factors, however, clinical consequences of the endogenous formation of trans fatty acids are not known but potentially important given available studies on TAA. This review aims to summarize the emerging role of TAA as a unique group of biomarkers that target microcirculation and other systems. A biological mechanism that generates endogenous trans fatty acids poses new challenges for pharmacologic intervention and we suggest approaches that may limit TAA effects. PMID:18606454

Balazy, Michael; Chemtob, Sylvain

2008-09-01

268

Molecular Dynamics Simulations of Arachidonic Acid Complexes with COX-1 and COX-2  

PubMed Central

The cyclooxygenase (COX) enzymes are responsible for the committed step in prostaglandin biosynthesis, the generation of prostaglandin H2. As a result, these enzymes are pharmacologically important targets for non-steroidal anti-inflammatory drugs, such as aspirin and newer COX-2 selective inhibitors. The cyclooxygenases are functional homodimers, and each subunit contains both a cyclooxygenase and a peroxidase active site. These enzymes are quite interesting mechanistically, as the conversion of arachidonic acid to prostaglandin H2 requires two oxygenation and two cyclization reactions, resulting in the formation of five new chiral centers with nearly absolute regio- and stereochemical fidelity. We have used molecular dynamics (MD) simulations to investigate the equilibrium behavior of both COX-1 and COX-2 enzyme isoforms with bound arachidonate. These simulations were compared with reference simulations of arachidonate in solution to explore the effect of enzyme on substrate conformation and positioning in the active site. The simulations suggest that the substrate has greater conformational freedom in the COX-2 active site, consistent with the larger COX-2 active site volume observed in X-ray crystal structures. The simulations reveal different conformational behavior for arachidonate in each subunit over the course of extended equilibrium MD simulations. The simulations also provide detailed information for several protein channels that might be important for oxygen and water transport to or from active sites, or for intermediate trafficking between the cyclooxygenase and peroxidase active sites. The detailed comparisons for COX-1 versus COX-2 active site structural fluctuations may also provide useful information for design of new isozyme-selective inhibitors.

Furse, Kristina E.; Pratt, Derek A.; Porter, Ned A.; Lybrand, Terry P.

2008-01-01

269

Intrauterine, postpartum and adult relationships between arachidonic acid (AA) and docosahexaenoic acid (DHA)  

Microsoft Academic Search

Erythrocyte (RBC) fatty acid compositions from populations with stable dietary habits but large variations in RBC-arachidonic (AA) and RBC-docosahexaenoic acid (DHA) provided us with insight into relationships between DHA and AA. It also enabled us to estimate the maternal RBC-DHA (mRBC-DHA) status that corresponded with no decrease in mRBC-DHA during pregnancy, or in infant (i) RBC-DHA or mRBC-DHA during the

Remko S. Kuipers; Martine F. Luxwolda; D. A. Janneke Dijck-Brouwer; Frits A. J. Muskiet

2011-01-01

270

Arachidonic Acid Can Significantly Prevent Early Insulin Resistance Induced by a High-Fat Diet  

Microsoft Academic Search

Aim: To investigate whole-body metabolic disorder and hepatic glucose output (HGO) disturbance in rats with insulin resistance induced by a short-term high-fat diet, and the effect of arachidonic acid (AA). Methods: Twenty-four normal male Wistar rats (230–250 g) were randomly divided into 3 groups according to their weight and fed for 12 weeks: control group, n = 8, fed with

Mianyun Wu; Ximing Wang; Qiuhong Duan; Tao Lu

2007-01-01

271

Elevated levels of arachidonic acid in fish from northern Australian coastal waters  

Microsoft Academic Search

The fatty acid composition of 10 species of fish caught off the northwest coast of Australia (latitude 17S) was examined.\\u000a All species contained high levels of ?6 fatty acids (9.6–23.1% of total fatty acids) with arachidonic acid being the major\\u000a ?6 fatty acid (5.9–14.8% of fatty acids). Docosatetraenoic and docosapentaenoic acids of the ?6 series accounted for 3–8%\\u000a of the

Andrew J. Sinclair; Kerin O'Dea; Joan M. Naughton

1983-01-01

272

The effect of linoleic, arachidonic and eicosapentaenoic acid supplementation on prostacyclin production in rats  

Microsoft Academic Search

We examined the effect of dietary supplementation of linoleic acid (LA), arachidonic acid (AA) or eicosapentaenoic acid (EPA)\\u000a to rats fed a diet low in linoleic acid onin vitro andin vivo production of prostacyclin. Male Sprague Dawley rats were fed a high-fat diet (50% energy as fat, 1.5% linoleic acid) for\\u000a two weeks. Three of the groups were then supplemented

Neil J. Mann; Glenda E. Warrick; Kerin O'Dea; Howard R. Knapp; Andrew J. Sinclair

1994-01-01

273

Topiramate does not alter expression in rat brain of enzymes of arachidonic acid metabolism  

Microsoft Academic Search

Rationale: When administered chronically to rats, drugs that are effective in bipolar disorder—lithium and the anticonvulsants, valproic acid and carbamazepine —have been shown to downregulate the expression of certain enzymes involved in brain arachidonic acid (AA) release and cyclooxygenase (COX)-mediated metabolism. Phase II clinical trials with the anticonvulsant topiramate (2,3:4,5-bis-O-(1-methylethylidene)-beta-D-fructopyranose sulfamate) suggest that this drug may also be effective for

Sandra Ghelardoni; Richard P. Bazinet; Stanley I. Rapoport; Francesca Bosetti

2005-01-01

274

Methods for bone treatment by modulating an arachidonic acid metabolic or signaling pathway  

US Patent & Trademark Office Database

Methods for promoting osteogenesis to accelerate or enhance bone fracture healing, treat bone defects, and enhance bone formation are disclosed. The methods modulate an arachidonic acid metabolic or signaling pathway in general, and, in particular, utilize 5-lipoxygenase inhibitors. These molecules can be delivered alone or in combination with one or more agents that inhibit bone resorption, regulate calcium resorption from bone, enhance bone accumulation, enhance bone formation, induce bone formation, impair growth of microorganisms, reduce inflammation, and/or reduce pain.

2010-11-09

275

Conjugated linoleic acid reduces arachidonic acid content and PGE 2 synthesis in murine keratinocytes  

Microsoft Academic Search

Dietary conjugated linoleic acid (CLA) is associated with decreased 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced tumor promotion in mouse skin. In addition, CLA decreases TPA-induced prostaglandin E synthesis and ornithine decarboxylase activity in cultured keratinocytes compared with linoleic acid (LA) and arachidonic acid (AA). When LA or CLA was added to keratinocyte cell cultures, the amounts of each of these cellular fatty acids increased

Kai-Li Liu; Martha A Belury

1998-01-01

276

Enhancement of arachidonic acid signaling pathway by nicotinic acid receptor HM74A  

Microsoft Academic Search

HM74A is a G protein-coupled receptor for nicotinic acid (niacin), which has been used clinically to treat dyslipidemia for decades. The molecular mechanisms whereby niacin exerts its pleiotropic effects on lipid metabolism remain largely unknown. In addition, the most common side effect in niacin therapy is skin flushing that is caused by prostaglandin release, suggesting that the phospholipase A2 (PLA2)\\/arachidonic

Yuting. Tang; Lubing Zhou; Joseph W. Gunnet; Pamela G. Wines; Ellen V. Cryan; Keith T. Demarest

2006-01-01

277

Effect of calcium ion on fatty acid-induced generation of superoxide in guinea pig neutrophils.  

PubMed

When phospholipases of plasma membranes are activated by certain stimuli, unsaturated fatty acids are liberated. Because unsaturated fatty acids enhance the transmembrane movement of calcium ions, the fatty acids released may modulate intracellular calcium homeostasis in various cells, including neutrophils. To determine the physiological function of these unsaturated fatty acids, we studied the effects of various fatty acids on superoxide generation and on changes in intracellular calcium contents of guinea pig neutrophils. Some unsaturated fatty acids, arachidonate and linoleate, stimulated the rate of superoxide generation concomitant with the increase in the amount of intracellular calcium. In contrast, the saturated fatty acid, myristate, stimulated the generation of superoxide without affecting the content of intracellular calcium. The stimulating actions of arachidonate and myristate were increased dramatically by the presence of a low concentration (1 microM) of extracellular calcium ion. The rate of superoxide generation in fatty acid-treated neutrophils was inhibited by chlorpromazine, an inhibitor of such calcium-binding proteins as C-kinase. These and other observations suggest that liberated unsaturated fatty acids increase the amount of intracellular calcium and enhance C-kinase activity also that the increased activity of the enzyme is involved in the chain of events leading to the stimulation of superoxide generation in fatty acid-treated neutrophils. PMID:3015427

Morimoto, Y M; Sato, E; Nobori, K; Takahashi, R; Utsumi, K

1986-06-01

278

?- and ?-adrenergic stimulation of arachidonic acid metabolism in cells in culture  

PubMed Central

Madin—Darby canine kidney cells (MDCK) synthesize prostaglandin (PG) F2?, PGI2 (measured as 6-keto-PGE1?), PGE2, PGD2, and thromboxane A2 (measured as thromboxane B2). When incubated in the presence of norepinephrine (6 ?M), the syntheses of these arachidonic acid metabolites are stimulated 3-fold. Norepinephrine's effect can be antagonized by the addition of ?-adrenergic receptor blocking agents (phenoxybenzamine>phentolamine>yohimbine>dibenamine>tolazoline) but not by the ?-adrenergic blocking drug propranolol. Norepinephrine's stimulation is also inhibited by low concentrations of dihydroergotamine, bromocryptine, ergocryptine, and ergotamine. The stimulation of PG synthesis by norepinephrine is reversible, continues during the 24 hr of incubation, and requires the presence of norepinephrine at the receptor site but it is not blocked by the addition of colchicine, cytochalasin B, or cycloheximide. Neither phenoxybenzamine nor ergotamine at concentrations that block norepinephrine's stimulation of PG biosynthesis suppresses the increase in PG synthesis induced by exogenous arachidonic acid, suggesting that the ?-adrenergic regulation is not occurring primarily at the cyclooxygenase step in the metabolism of arachidonic acid. In mouse lymphoma cells (WEHI-5), low concentrations of isoproterenol or norepinephrine stimulate the synthesis of thromboxane, an effect that can be blocked by the addition of propranolol but not by relatively high concentrations of phenoxybenzamine or ergotamine. Taken together, these results suggest that ?-adrenergic receptor stimulation promotes the deacylation of phospholipids by MDCK cells whereas ?-adrenergic mechanisms lead to activation of similar pathways in WEHI-5 cells.

Levine, Lawrence; Moskowitz, Michael A.

1979-01-01

279

Targeted Chiral Analysis of Bioactive Arachidonic Acid Metabolites Using Liquid-Chromatography-Mass Spectrometry  

PubMed Central

A complex structurally diverse series of eicosanoids arises from the metabolism of arachidonic acid. The metabolic profile is further complicated by the enantioselectivity of eicosanoid formation and the variety of regioisomers that arise. In order to investigate the metabolism of arachidonic acid in vitro or in vivo, targeted methods are advantageous in order to distinguish between the complex isomeric mixtures that can arise by different metabolic pathways. Over the last several years this targeted approach has become more popular, although there are still relatively few examples where chiral targeted approaches have been employed to directly analyze complex enantiomeric mixtures. To efficiently conduct targeted eicosanoid analyses, LC separations are coupled with collision induced dissociation (CID) and tandem mass spectrometry (MS/MS). Product ion profiles are often diagnostic for particular regioisomers. The highest sensitivity that can be achieved involves the use of selected reaction monitoring/mass spectrometry (SRM/MS); whereas the highest specificity is obtained with an SRM transitions between an intense parent ion, which contains the intact molecule (M) and a structurally significant product ion. This review article provides an overview of arachidonic acid metabolism and targeted chiral methods that have been utilized for the analysis of the structurally diverse eicosanoids that arise.

Mesaros, Clementina; Blair, Ian A.

2012-01-01

280

Increased metabolism of arachidonic acid in an immune model of colitis in guinea-pigs.  

PubMed Central

Inflammation of the guinea-pig colon was produced by skin sensitization and subsequent intracolonic challenge with the chemical hapten, dinitrochlorobenzene. Metabolism of [14C]-arachidonic acid by homogenates of control colon was very low, although metabolites co-migrating on thin layer chromatography (t.l.c.) with prostaglandin E2 (PGE2), PGF2 alpha, PGD2, 6-keto-PGF1 alpha, thromboxane B2 (TXB2), HHT and 11-, 12-, 15-HETE were formed. There was an overall 3 fold increase in metabolism of [14C]-arachidonic acid by homogenates of inflamed mucosa. The greatest increase in metabolite formation was of PGE2, with smaller increases in HHT, 11-, 12-, 15-HETE, PGD2, TXB2, PGF2 alpha and 6-keto-PGF1 alpha. The formation of these metabolites was inhibited both by indomethacin and the dual pathway inhibitor, BW755C. The formation of immunoreactive PGE2, TXB2 and 6-keto-PGF1 alpha was also increased in homogenates of inflamed guinea-pig colon. The small level of immunoreactive LTB4 detected in control colon was not changed in inflamed colonic tissue. The dinitrochlorobenzene model of colitis offers a means of studying arachidonic acid metabolism in an immune-mediated inflammatory response in intestinal tissue. Images Figure 1

Boughton-Smith, N. K.; Whittle, B. J.

1985-01-01

281

Self-Ear-Cleaning Among Educated Young Adults in Nigeria  

PubMed Central

Context: Self-ear-cleaning has been reported to be common from several hospital-based studies and it has been associated with some diseases of the ear. Aims: To determine community-based prevalence of self-ear-cleaning and its sociodemographic correlates among educated young adults in Nigeria. Settings and Design: A cross-sectional survey conducted in a National Youth Service Corps camp in Nigeria. Subjects and Methods: Semistructured questionnaires were administered on a randomly selected sample of 1280 respondents. The outcome variable was self-ear-cleaning. Independent variables were sociodemographic variables, materials used and ear-cleaning habits. Statistical Analysis Used: Statistical Package for the Social Sciences (SPSS) version 15 was utilized for univariate, bivariate, and multiple logistic regression analysis. Results: There were 1012 respondents (M: F = 1.05:1). Mean age was 25.3 (standard deviation, 2.34). Prevalence of self-ear-cleaning was 93.4%. Mean age at first cleaning was 7.6 years. Cotton buds were the most frequently used objects (in 85.1%). Prevalence was high irrespective of sociodemographic class, significantly higher among females (?2 = 4.549, P = 0.033), those who believed the habit was beneficial (?2 = 114.185, P < 0.001) and those whose parents and siblings practiced the habit. Significant predictive factors were self-ear-cleaning in respondent's father [odds ratio (OR) P = 0.011) and owning cotton buds (OR = 0.192, P = 0.007). Conclusions: Self-ear-cleaning is almost universal. Most of the population is, therefore, at risk of possible harmful effects. Also, medical advice against self-ear-cleaning is not widely known. Rather, the erroneous perception that self-ear-cleaning is beneficial is common. Collaborative health education efforts targeted at families and schools and campaigns and advocacy for legislation regulating the sale of cotton buds are recommended.

Olaosun, Adedayo Olugbenga

2014-01-01

282

The prevalence of middle ear pathogens in the outer ear canal and the nasopharyngeal cavity of healthy young adults.  

PubMed

Culturing middle ear fluid samples from children with chronic otitis media with effusion (OME) using standard techniques results in the isolation of bacterial species in approximately 30-50% of the cases. Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis, the classic middle ear pathogens of acute otitis media, are involved but, recently, several studies suggested Alloiococcus otitidis as an additional pathogen. In the present study, we used species-specific PCRs to establish the prevalence, in both the nasopharyngeal cavity and the outer ear, of H. influenzae, M. catarrhalis, S. pneumoniae and A. otitidis. The study group consisted of 70 healthy volunteers (aged 19-22 years). The results indicate a high prevalence (>80%) of A. otitidis in the outer ear in contrast to its absence in the nasopharynx. H. influenzae was found in both the outer ear and the nasopharynx (6% and 14%, respectively), whereas S. pneumoniae and M. catarrhalis were found only in the nasopharynx (9% and 34%, respectively).A. otitidis, described as a fastidious organism, were able to be cultured using an optimized culture protocol, with prolonged incubation, which allowed the isolation of A. otitidis in five of the nine PCR-positive samples out of the total of ten samples tested. Given the absence of the outer ear inhabitant A. otitidis from the nasopharynx, its role in the aetiology of OME remains ambiguous because middle ear infecting organisms are considered to invade the middle ear from the nasopharynx through the Eustachian tube. PMID:19895585

De Baere, T; Vaneechoutte, M; Deschaght, P; Huyghe, J; Dhooge, I

2010-07-01

283

The comparative anatomy of the pig middle ear cavity: a model for middle ear inflammation in the human?  

PubMed Central

This study was undertaken to develop a functional model of otitis media with effusion (OME) in the pig (Sus scrofa), with the purpose of investigating the origin of lymphocytes populating the middle ear during the course of an inflammatory process. The relevance of the model to the human condition of OME is to a large extent dependent on the anatomical and physiological similarities between the middle ear cavity and the pharyngeal lymphoid tissue of the pig and man. Anatomical specimens were collected from 7 young Large White pigs to determine the gross anatomy of the middle ear cavity and the histological characteristics of the middle ear mucosa. It was found that the anatomy of the 3 parts of the middle ear cavity in man and in the pig is broadly similar, although some minor differences were observed. The porcine eustachian tube was seen to be cartilaginous throughout its length in contrast to the part osseous, part cartilaginous structure found in man; the porcine ossicles were slightly different in shape to those of man and the air cell system was situated inferior to the tympanic cavity in the pig as opposed to posteriorly in man. This paper describes the structure and morphology of the pig middle ear cavity and compares and contrasts it with that of man. The minor differences observed are of anatomical importance but do not diminish the usefulness of the pig middle ear cleft as a potential model for human middle ear disorders.

PRACY, J. P.; WHITE, A.; MUSTAFA, Y.; SMITH, D.; PERRY, M. E.

1998-01-01

284

3D visualization of middle ear structures  

NASA Astrophysics Data System (ADS)

The achievement of volume geometry data from middle ear structures and surrounding components performs a necessary supposition for the finite element simulation of the vibrational and transfer characteristics of the ossicular chain. So far those models base on generalized figures and size data from anatomy textbooks or particular manual and one- or two-dimensional distance measurements of single ossicles, mostly obtained by light microscopy, respectively. Therefore the goal of this study is to create a procedure for complete three-dimensional imaging of real middle ear structures (tympanic membrane, ossicles, ligaments) in vitro or even in vivo. The main problems are their microscopic size with relevant structures from 10 micrometer to 5 mm, representing various tissue properties (bone, soft tissue). Additionally, these structures are surrounded by the temporal bone, the most solid bone of the human body. Generally there exist several established diagnostic tools for medical imaging that could be used for geometry data acquisition, e.g., X-ray computed tomography and magnetic resonance imaging. Basically they image different tissue parameters, either bony structures (ossicles), or soft tissue (tympanic membrane, ligaments). But considering this application those standard techniques allow low spatial resolution only, usually in the 0.5 - 1mm range, at least in one spatial direction. Thus particular structures of the middle ear region could even be missed completely because of their spatial location. In vitro there is a way out by collecting three complete data sets, each distinguished by 90 degree rotation of a cube-shaped temporal bone specimen. That allows high-resolution imaging in three orthogonal planes, which essentially supports the three-dimensional interpolation of the unknown elements, starting from the regularly set elements of the cubic grid with an edge extension given by the original two-dimensional matrix. A different approach represents the application of a micro- tomographic imaging device. Therefore an X-ray beam focused down to few microns passes the object in a tomographic arrangement. Subsequently the slices become reconstructed. Generally spatial resolution down to 10 micrometer may be obtained by using this procedure. But there exist few devices only, it is not available as standard equipment. The best results concerning spatial resolution should be achieved by applying conventional histologic sectioning techniques. Of course the target will become destroyed during the procedure. It is cut into sections (e.g., 10 micrometer thick), every layer is stained, and the image acquired and stored by a digital still-camera with appropriate resolution (e.g., 2024 X 3036). Three-dimensional reconstruction is done with the computer. The staining allows visual selection of bones and soft tissues, resolutions down to 10 micrometer are possible without target segmentation. But there arise some practical problems. Mainly the geometric context of the layers is affected by the cutting procedure, especially if cutting bone. Another problem performs the adjustment of the -- possibly distorted -- slices to each other. Artificial markers are necessary, which could allow automatic adjustment too. But the introduction and imaging of the markers is difficult inside the temporal bone specimen, that is interspersed by several cavities. Of course the internal target structures must not be destroyed by the marker introduction. Furthermore the embedding compound could disturb the image acquisition, e.g., by optical scattering of paraffin. A related alternative is given by layered ablation/grinding and imaging of the top layer. This saves the geometric consistency, but requires very tricky and time-consuming embedding procedures. Both approaches require considerable expenditures. The possible approaches are evaluated in detail and first results are compared. So far none of the above-mentioned procedures has been established as a standard tool for three-dimensional geometry data acquisition of the middle ear. Otherwise the establi

Vogel, Uwe; Schmitt, Thomas

1998-06-01

285

Analysis of Earing in Deep Drawn Cups  

SciTech Connect

The cup-drawing of a strongly anisotropic sheet metal is simulated using a commercial finite element software along with a user material subroutine. In order to accurately describe the plastic anisotropy of the material the well-known recent yield function 'Yld2004-18p' is extended. Regarding the experimental characterization of the considered material the occurrence of dynamic strain aging lead to an oscillating signal of the width change of the tensile samples, which prevented a reliable determination of plastic strain ratios (r-values). Thus, an improved measurement concept was developed that leads to a very robust and reproducible determination of r-values. Furthermore, a novel plane-strain tensile test sample is presented which is used for the characterization of the plastic anisotropy in biaxial loading states. A quantitative comparison with measured earing profiles of deep drawn cups illustrates the predictive capabilities of the numerical simulation.

Aretz, Holger; Aegerter, Johannes; Engler, Olaf [Hydro Aluminium Deutschland GmbH, Research and Development, Georg-von-Boeselager-Str. 21, D-53117 Bonn (Germany)

2010-06-15

286

Dichotic recognition of musical canons: Effects of leading ear and time lag between ears  

Microsoft Academic Search

A musical canon consists of two melodic lines with the second part copying the first exactly after some time delay. Right-handed\\u000a adults listened to canons presented dichotically at time delays between the ears of 2, 4, and 8 sec. Presentation rate varied\\u000a from 1.0 to 4.4 notes\\/sec in one part. Different groups of subjects heard the canons with the left

W. J. Dowling

1978-01-01

287

Nicotinic acid induces secretion of prostaglandin D 2 in human macrophages: An in vitro model of the niacin flush  

Microsoft Academic Search

Nicotinic acid is a safe, broad-spectrum lipid agent shown to prevent cardiovascular disease, yet its widespread use is limited by the prostaglandin D2 (PGD2) mediated niacin flush. Previous research suggests that nicotinic acid-induced PGD2 secretion is mediated by the skin, but the exact cell type remains unclear. We hypothesized that macrophages are a source of nicotinic acid-induced PGD2 secretion and

C. Daniel Meyers; Paul Liu; Vaijinath S. Kamanna; Moti L. Kashyap

2007-01-01

288

Percentages of oleic acid and arachidonic acid are inversely related in phospholipids of human sera  

PubMed Central

Background Many health effects of oils rich in oleic acid (18:1 n9) seem to be opposite those of arachidonic acid (20:4 n6), i.e. concerning cardiovascular risk. In recent study in rats we observed that percentages of oleic acid and arachidonic acid were inversely related in total serum lipids. In the present work we investigate whether an inverse relationship between this couple of fatty acids also exists in the phospholipid fraction of human sera. Methods The study group consisted of 11 men and 35 women. Mean age was 23.8?±?2.5 years (mean?±?SD), and the body mass index was 23.5?±?3.2 kg/m2. After fasting overnight, blood was drawn and the concentration of fatty acids in serum phospholipids was determined, using gas chromatography. We studied the association between percentages of oleic acid and arachidonic acid using bivariate correlations (Pearson), and multiple linear regressions. Results We found an inverse relationship (r?=??0.563, p?arachidonic acid in the serum phosholipid fraction of the 46 fasting subjects. By multiple linear regression, and % 20:4 n6 as the dependent variable, the inverse association with % 18:1 n9 persisted when controlling for sex, age, body mass index, and percentages of the other fatty acids measured (t?=??17.6, p?arachidonic acid were inversely related, and the inverse association persisted when controlling for possible confounding variables. The findings might contribute to explain positive health effects of foods rich in oleic acid.

2013-01-01

289

Hydrostatic pressure in the inner ear fluid compartments and its effects on inner ear function.  

PubMed

The present study summarizes the experimental findings obtained on the pressure in the inner ear fluids and on the effects of pressure changes on cochlear function in the guinea pig. Two types of pressures have to be distinguished in the inner ear fluid compartments: (i) hydrostatic fluid pressure and (ii) superimposed hydrodynamic high frequency (> 100 Hz) sound pressure oscillations. Hydrostatic pressure in the inner ear fluids in guinea pigs is in the order of 200 Pa (2 cm H2O) and shows slow (< 5 Hz) respiratory and pulsatory oscillations as well as considerable physiological variations in the range of -100 to +700 Pa. In normal ears, hydrostatic pressure in the perilymph equals pressure in the endolymph, and pressure changes applied to one compartment are immediately transmitted to the other one. A high compliance of Reissner's membrane seems to be the cause of this endolymphatic-perilymphatic pressure equalization. In experimental endolymphatic hydrops, a unique animal model for Meniere's disease, endolymphatic pressure is higher (100 Pa and above) than perilymphatic pressure. These pressure gradients occur only in late stages of hydrops, probably when Reissner's membrane has lost its high compliance after long standing distension. Positive endolymphatic-perilymphatic pressure gradients are secondary to and not the primary cause of hydrops formation. Changes of hydrostatic pressure do not affect auditory function as long as they stay in the physiological range. This includes the sudden loss of positive inner ear pressure that occurs in perilymph fistulas. The rationale for surgical repair of perilymph fistulas in patients in order to restore the hearing function thus becomes questionable. Other aspects of surgical repair, however, as e.g. prevention of labyrinthitis due to permanently open fistula, could not be investigated in this model, because in guinea pigs even large fistulas heal spontaneously within a few days. In experimental endolymphatic hydrops, deterioration of auditory thresholds was partially correlated to the presence of positive endolymphatic-perilymphatic pressure gradients. A change in pressure, however, occurred later than the first deterioration in auditory function. Therefore positive endo-perilymphatic pressure gradients may contribute to, but are not the only cause of hearing impairment. PMID:8273452

Böhmer, A

1993-01-01

290

Inverse solution of ear-canal area function from reflectance  

PubMed Central

A number of acoustical applications require the transformation of acoustical quantities, such as impedance and pressure that are measured at the entrance of the ear canal, to quantities at the eardrum. This transformation often requires knowledge of the shape of the ear canal. Previous attempts to measure ear-canal area functions were either invasive, non-reproducible, or could only measure the area function up to a point mid-way along the canal. A method to determine the area function of the ear canal from measurements of acoustic impedance at the entrance of the ear canal is described. The method is based on a solution to the inverse problem in which measurements of impedance are used to calculate reflectance, which is then used to determine the area function of the canal. The mean ear-canal area function determined using this method is similar to mean ear-canal area functions measured by other researchers using different techniques. The advantage of the proposed method over previous methods is that it is non- invasive, fast, and reproducible.

Rasetshwane, Daniel M.; Neely, Stephen T.

2011-01-01

291

Prenatal Ultrasound Screening for External Ear Abnormality in the Fetuses  

PubMed Central

Objectives. To investigate the best time of examination and section chosen of routine prenatal ultrasound screening for external ear abnormalities and evaluate the feasibility of examining the fetal external ear with ultrasonography. Methods. From July 2010 until August 2011, 42118 pregnant women with single fetus during 16–40 weeks of pregnancy were enrolled in the study. Fetal auricles and external auditory canal in the second trimester of pregnancy were evaluated by routine color Doppler ultrasound screening and systematic screening. Ultrasound images of fetal external ears were obtained on transverse-incline view at cervical vertebra level and mandible level and on parasagittal view and coronal view at external ear level. Results. Five fetuses had anomalous ears including bilateral malformed auricles with malformed external auditory canal, unilateral deformed external ear, and unilateral microtia. The detection rate of both auricles was negatively correlated with gestational age. Of the 5843 fetuses undergoing a routine ultrasound screening, 5797 (99.21%) had bilateral auricles. Of the 4955 fetuses following systematic screening, all fetuses (100%) had bilateral auricles. The best time for fetal auricles observation with ultrasonography is 20–24 weeks of pregnancy. Conclusions. Detection of external ear abnormalities may assist in the diagnosis of chromosomal abnormalities.

Wei, Jun; Ran, Suzhen; Yang, Zhengchun; Lin, Yun; Tang, Jing

2014-01-01

292

Cells, molecules and morphogenesis: The making of the vertebrate ear  

PubMed Central

The development and evolution of mechanosensory cells and the vertebrate ear is reviewed with an emphasis on delineating the cellular, molecular and developmental basis of these changes. Outgroup comparisons suggests that mechanosensory cells are ancient features of multicellular organisms. Molecular evidence suggests that key genes involved in mechanosensory cell function and development are also conserved among metazoans. The divergent morphology of mechanosensory cells across phyla is interpreted here as ‘deep molecular homology’ that was in parallel shaped into different forms in each lineage. The vertebrate mechanosensory hair cell and its associated neuron are interpreted as uniquely derived features of vertebrates. It is proposed that the vertebrate otic placode presents a unique embryonic adaptation in which the diffusely distributed ancestral mechanosensory cells became concentrated to generate a large neurosensory precursor population. Morphogenesis of the inner ear is reviewed and shown to depend on genes expressed in and around the hindbrain that interact with the otic placode to define boundaries and polarities. These patterning genes affect downstream genes needed to maintain proliferation and to execute ear morphogenesis. We propose that fibroblast growth factors (FGFs) and their receptors (FGFRs) are a crucial central node to translate patterning into the complex morphology of the vertebrate ear. Unfortunately, the FGF and FGFR genes have not been fully analyzed in the many mutants with morphogenetic ear defects described thus far. Likewise, little information exists on the ear histogenesis and neurogenesis in many mutants. Nevertheless, a molecular mechanism is now emerging for the formation of the horizontal canal, an evolutionary novelty of the gnathostome ear. The existing general module mediating vertical canal growth and morphogenesis was modified by two sets of new genes: one set responsible for horizontal canal morphogenesis and another set for neurosensory formation of the horizontal crista and associated sensory neurons. The dramatic progress in deciphering the molecular basis of ear morphogenesis offers grounds for optimism for translational research toward intervention in human morphogenetic defects of the ear.

Fritzsch, Bernd; Pauley, Sarah; Beisel, Kirk W.

2014-01-01

293

3D Ear Identification Based on Sparse Representation  

PubMed Central

Biometrics based personal authentication is an effective way for automatically recognizing, with a high confidence, a person’s identity. Recently, 3D ear shape has attracted tremendous interests in research field due to its richness of feature and ease of acquisition. However, the existing ICP (Iterative Closet Point)-based 3D ear matching methods prevalent in the literature are not quite efficient to cope with the one-to-many identification case. In this paper, we aim to fill this gap by proposing a novel effective fully automatic 3D ear identification system. We at first propose an accurate and efficient template-based ear detection method. By utilizing such a method, the extracted ear regions are represented in a common canonical coordinate system determined by the ear contour template, which facilitates much the following stages of feature extraction and classification. For each extracted 3D ear, a feature vector is generated as its representation by making use of a PCA-based local feature descriptor. At the stage of classification, we resort to the sparse representation based classification approach, which actually solves an l1-minimization problem. To the best of our knowledge, this is the first work introducing the sparse representation framework into the field of 3D ear identification. Extensive experiments conducted on a benchmark dataset corroborate the effectiveness and efficiency of the proposed approach. The associated Matlab source code and the evaluation results have been made publicly online available at http://sse.tongji.edu.cn/linzhang/ear/srcear/srcear.htm.

Zhang, Lin; Ding, Zhixuan; Li, Hongyu; Shen, Ying

2014-01-01

294

3D ear identification based on sparse representation.  

PubMed

Biometrics based personal authentication is an effective way for automatically recognizing, with a high confidence, a person's identity. Recently, 3D ear shape has attracted tremendous interests in research field due to its richness of feature and ease of acquisition. However, the existing ICP (Iterative Closet Point)-based 3D ear matching methods prevalent in the literature are not quite efficient to cope with the one-to-many identification case. In this paper, we aim to fill this gap by proposing a novel effective fully automatic 3D ear identification system. We at first propose an accurate and efficient template-based ear detection method. By utilizing such a method, the extracted ear regions are represented in a common canonical coordinate system determined by the ear contour template, which facilitates much the following stages of feature extraction and classification. For each extracted 3D ear, a feature vector is generated as its representation by making use of a PCA-based local feature descriptor. At the stage of classification, we resort to the sparse representation based classification approach, which actually solves an l1-minimization problem. To the best of our knowledge, this is the first work introducing the sparse representation framework into the field of 3D ear identification. Extensive experiments conducted on a benchmark dataset corroborate the effectiveness and efficiency of the proposed approach. The associated Matlab source code and the evaluation results have been made publicly online available at http://sse.tongji.edu.cn/linzhang/ear/srcear/srcear.htm. PMID:24740247

Zhang, Lin; Ding, Zhixuan; Li, Hongyu; Shen, Ying

2014-01-01

295

Benfotiamine attenuates nicotine and uric acid-induced vascular endothelial dysfunction in the rat.  

PubMed

The study has been designed to investigate the effect of benfotiamine, a thiamine derivative, in nicotine and uric acid-induced vascular endothelial dysfunction (VED) in rats. Nicotine (2 mg kg(-1)day(-1), i.p., 4 weeks) and uric acid (150 mg kg(-1)day(-1), i.p., 3 weeks) were administered to produce VED in rats. The development of VED was assessed by employing isolated aortic ring preparation and estimating serum and aortic concentration of nitrite/nitrate. Further, the integrity of vascular endothelium was assessed using the scanning electron microscopy (SEM) of thoracic aorta. Moreover, the oxidative stress was assessed by estimating serum thiobarbituric acid reactive substances (TBARS) and aortic superoxide anion generation. The administration of nicotine and uric acid produced VED by impairing the integrity of vascular endothelium and subsequently decreasing serum and aortic concentration of nitrite/nitrate and attenuating acetylcholine-induced endothelium dependent relaxation. Further, nicotine and uric acid produced oxidative stress, which was assessed in terms of increase in serum TBARS and aortic superoxide generation. However, treatment with benfotiamine (70 mg kg(-1)day(-1), p.o.) or atorvastatin (30 mg kg(-1)day(-1) p.o., a standard agent) markedly prevented nicotine and uric acid-induced VED and oxidative stress by improving the integrity of vascular endothelium, increasing the concentration of serum and aortic nitrite/nitrate, enhancing the acetylcholine-induced endothelium dependent relaxation and decreasing serum TBARS and aortic superoxide anion generation. Thus, it may be concluded that benfotiamine reduces the oxidative stress and consequently improves the integrity of vascular endothelium and enhances the generation of nitric oxide to prevent nicotine and uric acid-induced experimental VED. PMID:18951979

Balakumar, Pitchai; Sharma, Ramica; Singh, Manjeet

2008-01-01

296

A Case of Atypical Granuloma Annulare Involving Both Ears  

PubMed Central

We report a rare case of granuloma annulare (GA), affecting both ear antihelixes, in a 28-year old male patient that presented with a 1-year history of non-tender, firm, skin-colored, 1~5 mm papules on both ear antihelixes. There was no history of trauma. An excisional biopsy specimen taken from one of the lesions of the right ear revealed infiltration of histiocytes and lymphocytes around a zone of collagen alteration in the dermis. Based on the clinical and pathological findings, the patient was diagnosed with a rare case of bilateral GA of both antihelixes; this is the first report in the Korean dermatology literature.

Kim, Jin Gu; Lee, Seung Hun

2009-01-01

297

Acute effects of irradiation on middle ear mucosa  

SciTech Connect

Single field, fixed irradiation of bilateral tympanic cavities using 200-kV x-rays was administered to five guinea pigs. The irradiation dose was 30 Gy. They were killed immediately after irradiation, and bilateral middle ear mucosa was examined for ciliary activity and epithelial structure. Significant deterioration of the ciliary activity in the middle ear mucosa was observed, proximal as well as distal to the eustachian tube. Electron microscopy showed various changes in the irradiated middle ear mucosa. The most conspicuous findings were hyperreactivity in secretion, vacuolation of ciliated cells, and stomal edema.

Ohashi, Y.; Nakai, Y.; Esaki, Y.; Ikeoka, H.; Koshimo, H.; Onoyama, Y.

1988-03-01

298

Functional evaluation of iodoacetic acid induced photoreceptor degeneration in the cat.  

PubMed

Iodoacetic acid (IAA) has been applied to different species to acutely induce photoreceptor degeneration. The purpose of the present study was to use this toxin to thoroughly eliminate photoreceptors and induce complete blindness in the cat. IAA was delivered by single ear vein injection (20 mg kg(-1)). Six months after the IAA treatment, functional evaluations including pupillary light reflex (PLR), electroretinogram (ERG), visual behavior tests were performed. Morphological examinations were carried out after the functional evaluation. The present result shows that, six months after the IAA application, animals lost visual functions and became completely blind. High dose IAA application via ear vein delivery created an acute and reliable complete photoreceptor degeneration model in the cat. This model can be applied to genetic and cellular therapies for visual function restoration. PMID:23657794

Nan, Yan; Zhang, Qin; Ren, Chaoran; Huang, Xin; Gao, Jie; Li, Xiaoxin; Pu, Mingliang

2013-06-01

299

Evolution of Gravity Receptors in the Ear  

NASA Technical Reports Server (NTRS)

The general status of a grant to investigate the origins and evolution of two hair cell types in the ears of a teleost fish, Astronotus ocellatus (the oscar), is presented. First, it was demonstrated that the cells in the rostral end of the saccule of the , Carassius auratus, are type 1-like, while those at the caudal end are type 2 cells. It was demonstrated that the dichotomy of hair cell types found in the utricle of the oscar is also found in the goldfish. Second, the lateral line system of the oscar was examined using gentamicin sulphate, an ototocix drug that destroys type 1- like hair cells but does not appear to damage type 2 hair cells. It was demonstrated that the hair cells found in neuromasts of lateral line canal organs were totally destroyed within 1 day of treatment, while the hair cells in free neuromasts were undamaged after 12 days of treatment. Third, it was demonstrated that the calyx, the specialized nerve ending, is not unique to amniotes and that it is present at least in the cristae of semicirular canals in goldfish. These results have demonstrated that: (1) there are multiple hair cell types in the vestibular endorgans of the ear of fishes, (2) these hair cell types are very similar to those found in the mammalian vestibular endorgans, (3) the nerve calyx is also present in fishes, and (4) multiple hair cell types and the calyx have evolved far earlier in the course of vertebrate evolution than heretofore thought. Understanding the structure of the vestibular endorgans has important implications for being able to understand how these organs respond to gravistatic, acceleration and acoustic input. The vestibular endorgans of fishes may provide an ideal system in which to analyze functional differences in hair cells. Not only are the two hair cell types similar to those found in mammals, they are located in very discrete regions in each endorgan. Thus, it is relatively easy to gain access to cells of one or the other type. The presence of two cell types in the lateral line have equally significant implications for studies of the vestibular system.

Popper, Arthur N. (Principal Investigator)

1996-01-01

300

Coordinate Direction Normalization Using Point Cloud Projection Density for 3D Ear  

Microsoft Academic Search

Human ear has been long proved to be a promising candidate for personal identification. Human ear, with its 3D structure stability and detail expressive, has drawn researchers' attention recently. The posture of ear always changes to the motion of head, it is necessary to normalize an ear to a standard posture to ensure the accuracy of feature extraction. This paper

Chao Huang; Guangming Lu; Yahui Liu

2009-01-01

301

Comparison and Combination of Ear and Face Images in Appearance-Based Biometrics  

Microsoft Academic Search

Researchers have suggested that the ear may have advantages over the face for biometric recognition. Our previous experiments with ear and face recognition, using the standard principal component analysis approach, showed lower recognition performance using ear images. We report results of similar experiments on larger data sets that are more rigorously controlled for relative quality of face and ear images.

Kyong I. Chang; Kevin W. Bowyer; Sudeep Sarkar; Barnabas Victor

2003-01-01

302

Laser interferometric vibration measurements of the middle ear in healthy humans  

Microsoft Academic Search

The use of spontaneous and evoked otacoustic emissions is now a standard clinical tool for diagnosis of the function of the inner ear. However, it is not possible to extract this information over the entire, functionally relevant frequency range because of imperfect coupling of: (1) stapedial to ear-drum vibrations through the ossicular chain of the middle ear and (2) ear-drum

J. Rodriguez Jorge; Werner Hemmert; C. Burkhardt; Hans-Peter Zenner; Anthony W. Gummer

1996-01-01

303

Chronic Otitis Media (Middle Ear Infection) and Hearing Loss  

MedlinePLUS

... Vaccines Hearing Loss and Ear Infection Find an ENT Last Name ZIP Code More Options About Otolaryngology ... United States. Otolaryngologists are commonly referred to as ENT physicians. Learn More Free Download AAO-HNS MarketPlace ...

304

Barotrauma of the ears and sinuses after scuba diving.  

PubMed

The pathophysiology, differential diagnosis, and currently available management of barotrauma affecting the ears and sinuses after scuba diving are reviewed, along with medical standards for resuming scuba diving after barotrauma has resolved. PMID:11407445

Becker, G D; Parell, G J

2001-05-01

305

Ear morphology in treacher collins', apert's, and crouzon's syndromes  

Microsoft Academic Search

Size, proportions, level, inclination and shape of the ears were assessed by anthrompometric methods in eight patients with Treacher Collins' syndrome, eleven with Apert's, and 25 with Crouzon's syndrome.

L. G. Farkas; Walter Zingg

1978-01-01

306

Tympanostomy Tubes: A Rational Clinical Treatment for Middle Ear Disease.  

ERIC Educational Resources Information Center

The use of tympanostomy tubes to treat middle ear disease including otitis media is discussed with sections on the eustachian tube; acute otitis media; persistent effusion; changes in the tympanic membrane; special populations; and complications. (DB)

Roland, Peter S.; Brown, Orval

1990-01-01

307

Don't Get Burned: Stay Away from Ear Candles  

MedlinePLUS

... to three large manufacturers of ear candles. These firms were informed that FDA had determined that there was no agency approval or clearance, no manufacturing facility registration or device listing, and no adverse- ...

308

Get Smart: Know When Antibiotics Work - Ear Infections  

MedlinePLUS

... has and if antibiotics would help. Acute otitis media The type of ear infection that is usually ... for AOM, but are not always necessary. Otitis media with effusion Otitis media with effusion (uh-FEW- ...

309

Prescription Eardrops Seem Best for Kids with Recurrent Ear Infection  

MedlinePLUS

... please enable JavaScript. Prescription Eardrops Seem Best for Kids With Recurrent Ear Infection: Study Finds drops may ... infections are a near-constant problem. For these kids, small tubes -- known as tympanostomy tubes -- inserted into ...

310

How minute sooglossid frogs hear without a middle ear.  

PubMed

Acoustic communication is widespread in animals. According to the sensory drive hypothesis [Endler JA (1993) Philos Trans R Soc Lond B Biol Sci 340(1292):215-225], communication signals and perceptual systems have coevolved. A clear illustration of this is the evolution of the tetrapod middle ear, adapted to life on land. Here we report the discovery of a bone conduction-mediated stimulation of the ear by wave propagation in Sechellophryne gardineri, one of the world's smallest terrestrial tetrapods, which lacks a middle ear yet produces acoustic signals. Based on X-ray synchrotron holotomography, we measured the biomechanical properties of the otic tissues and modeled the acoustic propagation. Our models show how bone conduction enhanced by the resonating role of the mouth allows these seemingly deaf frogs to communicate effectively without a middle ear. PMID:24003145

Boistel, Renaud; Aubin, Thierry; Cloetens, Peter; Peyrin, Françoise; Scotti, Thierry; Herzog, Philippe; Gerlach, Justin; Pollet, Nicolas; Aubry, Jean-François

2013-09-17

311

Arachidonic acid can function as a signaling modulator by activating the TRPM5 cation channel in taste receptor cells.  

PubMed

Vertebrate sensory cells such as vomeronasal neurons and Drosophila photoreceptor cells use TRP channels to respond to exogenous stimuli. In mammalian taste cells, bitter and sweet substances as well as some amino acids are received by G protein-coupled receptors (T2Rs or T1Rs). As a result of activation of G protein and phospholipase Cbeta2, the TRPM5 channel is activated. Intracellular Ca(2+) is known to be a TRPM5 activator, but the participation of lipid activators remains unreported. To clarify the effect of arachidonic acid on TRPM5 in taste cells, we investigated the expression profile of a series of enzymes involved in controlling the intracellular free arachidonic acid level, with the result that in a subset of taste bud cells, monoglyceride lipase (MGL) and cyclooxygenase-2 (COX-2) are expressed as well as the previously reported group IIA phospholipase A(2) (PLA(2)-IIA). Double-labeling analysis revealed that MGL, COX-2 and PLA(2)-IIA are co-expressed in some cells that express TRPM5. We then investigated whether arachidonic acid activates TRPM5 via a heterologous expression system in HEK293 cells, and found that its activation occurred at 10 microM arachidonic acid. These results strongly suggest the possibility that arachidonic acid acts as a modulator of TRPM5 in taste signaling pathways. PMID:16935556

Oike, Hideaki; Wakamori, Minoru; Mori, Yasuo; Nakanishi, Hiroki; Taguchi, Ryo; Misaka, Takumi; Matsumoto, Ichiro; Abe, Keiko

2006-09-01

312

Arachidonic acid reciprocally alters the availability of transient and sustained dendritic K(+) channels in hippocampal CA1 pyramidal neurons.  

PubMed

The dendrites of hippocampal CA1 pyramidal cell dendrites express a high density of transient A-type K(+) channels, which play a critical role in the back-propagation of action potentials and in the determination of dendritic excitability. Recently, arachidonic acid and its nonmetabolizable analogue 5,8,11,14-eicosatetraynoic acid (ETYA) were shown to block transient K(+) channels in the somata of these cells (), but to have little effect on the somatic action potential. In the present study we have investigated the effects of arachidonic acid and ETYA on the gating of channels and the excitability of the apical dendrites of CA1 pyramidal neurons. We found not only a block of transient K(+) channels, but also an enhancement of sustained outward currents. The sustained currents consisted of at least two distinct channel types. The larger conductance channel (>50 pS) was identified as a K(+) channel. Arachidonic acid greatly enhanced the amplitude of back-propagating dendritic action potentials (>200 micrometer from the soma) but did not result in sustained depolarizations of the dendrites similar to those seen with 4-aminopyridine (4-AP) application. In fact, arachidonic acid reduced dendritic excitability when applied after 4-AP. Thus, arachidonic acid appears to cause a shift of available channels from the fast, transient type to the slower, sustained types. The net effect appears to be an enhancement of dendritic action potential amplitude that occurs without compromising the electrical stability of the dendrites. PMID:10493718

Colbert, C M; Pan, E

1999-10-01

313

Protein kinase C is involved in stimulation of arachidonic acid metabolism in Madin-Darby canine kidney (MDCK) cells  

SciTech Connect

The authors used 12-O-tetradecanoyl-phorbol-13-acetate (TPA) to directly stimulate protein kinase C (PKC) in order to examine the role of PKC in transduction of biological signals that increase metabolism of arachidonic acid. Release of radioactive arachidonic acid and prostaglandins from TPA-stimulated MDCK cells is inhibited by either of two PKC inhibitors: 1-(5-isoquinolinesulfonyl)piperazine and 1-octadecyl-2-methoxy-glycero-3-phosphocholine (ALP). ALP is unable to inhibit cyclooxygenase when added into an in vitro assay for this enzyme. Furthermore, TPA induces de novo synthesis of cyclooxygenase in MDCK cells but ALP fails to prevent this effect of TPA. Thus, cyclooxygenase activity appears to be independent of PKC and TPA can still induce de novo synthesis of cyclooxygenase even in the presence of the PKC inhibitor ALP. Also, ALP has no effect on the release of arachidonic acid which occurs upon addition of the calcium ionophore A23187 to MDCK cells suggesting that there are multiple mechanisms to mobilize arachidonic acid. Their data indicate that activation of PKC by TPA leads to increased release of arachidonic acid through regulation of phospholipase(s) by PKC.

Parker, J.; Daniel, L.W.; Waite, M.

1986-05-01

314

Salicylic acid induces mitochondrial injury by inhibiting ferrochelatase heme biosynthesis activity.  

PubMed

Salicylic acid is a classic nonsteroidal anti-inflammatory drug. Although salicylic acid also induces mitochondrial injury, the mechanism of its antimitochondrial activity is not well understood. In this study, by using a one-step affinity purification scheme with salicylic acid-immobilized beads, ferrochelatase (FECH), a homodimeric enzyme involved in heme biosynthesis in mitochondria, was identified as a new molecular target of salicylic acid. Moreover, the cocrystal structure of the FECH-salicylic acid complex was determined. Structural and biochemical studies showed that salicylic acid binds to the dimer interface of FECH in two possible orientations and inhibits its enzymatic activity. Mutational analysis confirmed that Trp301 and Leu311, hydrophobic amino acid residues located at the dimer interface, are directly involved in salicylic acid binding. On a gel filtration column, salicylic acid caused a shift in the elution profile of FECH, indicating that its conformational change is induced by salicylic acid binding. In cultured human cells, salicylic acid treatment or FECH knockdown inhibited heme synthesis, whereas salicylic acid did not exert its inhibitory effect in FECH knockdown cells. Concordantly, salicylic acid treatment or FECH knockdown inhibited heme synthesis in zebrafish embryos. Strikingly, the salicylic acid-induced effect in zebrafish was partially rescued by FECH overexpression. Taken together, these findings illustrate that FECH is responsible for salicylic acid-induced inhibition of heme synthesis, which may contribute to its antimitochondrial and anti-inflammatory function. This study establishes a novel aspect of the complex pharmacological effects of salicylic acid. PMID:24043703

Gupta, Vipul; Liu, Shujie; Ando, Hideki; Ishii, Ryohei; Tateno, Shumpei; Kaneko, Yuki; Yugami, Masato; Sakamoto, Satoshi; Yamaguchi, Yuki; Nureki, Osamu; Handa, Hiroshi

2013-12-01

315

STRUCTURAL REMODELING OF PROTEOGLYCANS UPON RETINOIC ACID-INDUCED DIFFERENTIATION OF NCCIT CELLS*  

PubMed Central

Pluripotent and multipotent cells become increasingly lineage restricted through differentiation. Alterations to the cellular proteoglycan composition and structure should accompany these changes to influence cell proliferation, delineation of tissues and acquisition of cell migration capabilities. Retinoic acid plays an important role in pre-patterning of the early embryo. Retinoic acid can be used in vitro to induce differentiation, causing pluripotent and multipotent cells to become increasingly lineage restricted. We examined retinoic acid-induced changes in the cellular proteoglycan composition of the well-characterized teratocarcinoma line NCCIT. Our analysis revealed changes in the abundance of transcripts for genes encoding core proteins, enzymes that are responsible for early and late linkage region biosynthesis, as well as enzymes for GAG chain extension and modification. Transcript levels for genes encoding core proteins used as backbones for polysaccharide synthesis revealed highly significant increases in expression of lumican and decorin, 1500-fold and 2800-fold, respectively. Similarly, glypican 3, glypican 5, versican and glypican 6 showed increases between 5 and 70-fold. Significant decreases in biglycan, serglycin, glypican 4, aggrecan, neurocan, CD74 and glypican 1 were observed. Disaccharide analysis of the glycans in heparin/heparan sulfate and chondroitin/dermatan sulfate revealed retinoic acid-induced changes restricted to chondroitin/dermatan sulfate glycans. Our study provides the first detailed analysis of changes in the glycosaminoglycan profile of human pluripotent cells upon treatment with the retinoic acid morphogen.

Gasimli, Leyla; Stansfield, Hope E.; Nairn, Alison V.; Liu, Haiying; Paluh, Janet L.; Yang, Bo; Dordick, Jonathan S.; Moremen, Kelley W.; Linhardt, Robert J.

2012-01-01

316

Acid-induced hyperalgesia and anxio-depressive comorbidity in rats.  

PubMed

Fibromyalgia is a prevalent disorder characterized by chronic widespread pain (CWP) and complex comorbid symptoms. A CWP model is developed through repeated unilateral intramuscular injections of acid saline resulting in bilateral mechanical hyperalgesia in rats. The present study aims to evaluate whether both anxious and depressive comorbidities exist in this acid-induced pain model, similarly to patients with CWP syndromes. The anxiety-like behaviors were evaluated using the open field and elevated plus maze tests, and depression-like behaviors were measured by the forced swimming, sucrose consumption, and sucrose preference tests. The pain group receiving acidic saline displayed significantly lower paw withdrawal thresholds for 4weeks than animals in the vehicle group after repetitive intramuscular injections. The pain group showed a significantly shorter duration of exploring the central zone of the open field and the open arms of the elevated plus maze compared to the vehicle group. The pain group had a significantly lower preference for and consumption of the hedonic sucrose. Moreover, rats with chronic pain showed significantly longer immobility than the vehicle group in the forced swimming test. The results indicate that psychiatric behaviors are exacerbated in the CWP model. This study provides evidence for the validity of the acid-induced pain model analogous to patients with CWP syndromes. PMID:24726391

Liu, Yu-Ting; Shao, Yen-Wen; Yen, Chen-Tung; Shaw, Fu-Zen

2014-05-28

317

Acid mediates a prolonged antinociception via substance P signaling in acid-induced chronic widespread pain  

PubMed Central

Background Substance P is an important neuropeptide released from nociceptors to mediate pain signals. We recently revealed antinociceptive signaling by substance P in acid-sensing ion channel 3 (ASIC3)-expressing muscle nociceptors in a mouse model of acid-induced chronic widespread pain. However, methods to specifically trigger the substance P antinociception were still lacking. Results Here we show that acid could induce antinociceptive signaling via substance P release in muscle. We prevented the intramuscular acid-induced hyperalgesia by pharmacological inhibition of ASIC3 and transient receptor potential V1 (TRPV1). The antinociceptive effect of non-ASIC3, non-TRPV1 acid signaling lasted for 2 days. The non-ASIC3, non-TRPV1 acid antinociception was largely abolished in mice lacking substance P. Moreover, pretreatment with substance P in muscle mimicked the acid antinociceptive effect and prevented the hyperalgesia induced by next-day acid injection. Conclusions Acid could mediate a prolonged antinociceptive signaling via the release of substance P from muscle afferent neurons in a non-ASIC3, non-TRPV1 manner.

2014-01-01

318

The involvement of endoplasmic reticulum stress in bile acid-induced hepatocellular injury  

PubMed Central

Secondary bile acids produced by enteric bacteria accumulate to high levels in the enterohepatic circulation and may contribute to the pathogenesis of hepatocellular injury. Relative hydrophobicity has been suggested to be an important determinant of the biological properties of these compounds, although the mechanism by which bile acids induce pathogenesis is not fully understood. On the other hand, endoplasmic reticulum stress has been shown to be involved in the induction and development of various pathogenic conditions. In this report, we demonstrated that the intensities of cytotoxicity and endoplasmic reticulum stress in HepG2 cells triggered by the bile acids tested were largely dependent on their hydrophobicity. The activation of caspase-3 and DNA fragmentation by treatment with chenodeoxycholic acid showed the contribution of apoptosis to cytotoxicity. Increases in intracellular calcium levels and the generation of reactive oxygen species stimulated by treatment with chenodeoxycholic acid contributed to endoplasmic reticulum stress. Bile acids also induced transforming growth factor-?, a potent profibrogenic factor, which is known to induce hepatocyte apoptosis and ultimately liver fibrosis. In conclusion, our study demonstrated that bile acids induced endoplasmic reticulum stress, which in turn stimulated apoptosis in HepG2 cells, in a hydrophobicity-dependent manner.

Adachi, Tetsuo; Kaminaga, Tomoyuki; Yasuda, Hiroyuki; Kamiya, Tetsuro; Hara, Hirokazu

2014-01-01

319

Uric acid-induced endothelial dysfunction is associated with mitochondrial alterations and decreased intracellular ATP concentrations  

PubMed Central

Background/Aims Endothelial dysfunction is associated with mitochondrial alterations. We hypothesized that uric acid, which can induce endothelial dysfunction in vitro and in vivo, might also alter mitochondrial function. Methods Human aortic endothelial cells were exposed to soluble uric acid and measurements of oxidative stress, nitric oxide, mitochondrial density, ATP production, aconitase-2 and enoyl co-A hydratase-1 expression, and aconitase-2 activity in isolated mitochondria were determined. The effect of hyperuricemia upon renal mitochondrial integrity was also assessed in rats treated with oxonic acid that inhibits the enzyme uricase that degrades uric acid. Results Uric acid induced endothelial dysfunction was associated with reduced mitochondrial mass and ATP production. Uric acid also decreased aconitase-2 activity and lowered enoyl CoA hydratase-1 expression. Hyperuricemic rats showed increased mitDNA damage in association with higher levels of intrarenal uric acid and oxidative stress. Conclusions Uric acid induced endothelial dysfunction is associated with mitochondrial alterations and decreased intracellular ATP. These studies provide additional evidence for a deleterious effect of UA on vascular function that could be important in the pathogenesis and progression of hypertension, vascular disease and renal disease.

Sanchez-Lozada, Laura Gabriela; Lanaspa, Miguel A.; Cristobal-Garcia, Magdalena; Garcia-Arroyo, Fernando; Soto, Virgilia; Cruz-Robles, David; Nakagawa, Takahiko; Yu, Min-A; Kang, Duk-Hee; Johnson, Richard J

2013-01-01

320

Morphometry of the External Ear in Our Adult Population  

Microsoft Academic Search

This study aimed to determine the mean values of the different morphometric measurements from right and left ears. These measurements\\u000a were taken from 341 healthy young adults (150 women and 191 men) ages 18 to 25 years using an electronic digital caliper.\\u000a The results showed the mean values for total ear height, lobular height and width, distances from tragus to

M. Gülhal Bozk?r; P?nar Karaka?; Metin Yavuz; Fahri Dere

2006-01-01

321

Efficient Parallel Graph Algorithms Based on Open Ear Decomposition  

Microsoft Academic Search

We present a new technique called disjoint decreasing ear paths, which is based on a graph's open ear decomposition. We apply this technique in CRCW PRAM parallel algorithms for the two vertex disjoint s — t paths problem and the maximal path problem in planar graphs. These run in O(log n) time with n + m processors and O(log2\\u000an)

Louis Ibarra; Dana S. Richards

1993-01-01

322

Measurement of sound transmission in the middle ear  

Microsoft Academic Search

In order to investigate the sound transmission in the middle ear in detail and the changes brought about by operations, an\\u000a appropriate transducer was developed. Modern techniques in operative treatment of otosclerosis change the acoustic parameters\\u000a of the ear; one of the operations is to penetrate the fixed stapedial footplate with a wire aftached to the incus to transmit\\u000a sound

H. Fischler; E. H. Frei; M. Rubinsteins; D. Spira

1964-01-01

323

Evidence of Inner Ear Contribution in Bone Conduction in Chinchilla  

PubMed Central

We investigated the contribution of the middle ear to the physiological response to bone conduction stimuli in chinchilla. We measured intracochlear sound pressure in response to air conduction (AC) and bone conduction (BC) stimuli before and after interruption of the ossicular chain at the incudo-stapedial joint. Interruption of the chain effectively decouples the external and middle ear from the inner ear and significantly reduces the contributions of the outer ear and middle ear to the bone conduction response. With AC stimulation, both the scala vestibuli Psv and scala tympani Pst sound pressures drop by 30 to 40 dB after the interruption. In BC stimulation, Psv decreases after interruption by about 10 to 20 dB, but Pst is little affected. This difference in the sensitivity of the BC induced Psv and Pst to ossicular interruption is not consistent with a BC response to ossicular motion, but instead suggests a significant contribution of an inner-ear drive (e.g. cochlear fluid inertia or compressibility) to the BC response.

Chhan, David; Roosli, Christof; McKinnon, Melissa L.; Rosowski, John J.

2013-01-01

324

Retinoid Signaling in Inner Ear Development: a "Goldilocks" Phenomenon  

PubMed Central

Retinoic acid is a biologically active derivative of vitamin A that is indispensable for inner ear development. The normal function of retinoic acid is achieved only at optimal homeostatic concentrations, with an excess or deficiency in retinoic acid leading to inner ear dysmorphogenesis. We present an overview of the role of retinoic acid in the developing mammalian inner ear, discussing both how and when retinoic acid may act to critically control a program of inner ear development. Molecular mechanisms of otic teratogenicity involving two members of the fibroblast growth factor family, FGF3 and FGF10, and their downstream targets, Dlx5 and Dlx6, are examined under conditions of both retinoic acid excess and deficiency. We term the effect of too little or too much retinoic acid on FGF/Dlx signaling a Goldilocks phenomenon. We demonstrate that in each case (retinoic acid excess, retinoic acid deficiency), retinoic acid can directly affect FGF3/FGF10 signaling within the otic epithelium, leading to downregulated expression of these essential signaling molecules, which in turn, leads to diminution in Dlx5/Dlx6 expression. Non-cell autonomous affects of the otic epithelium subsequently occur, altering transforming growth factor beta (TGF?) expression in the neighboring periotic mesenchyme and serving as a putative explanation for retinoic acid-mediated otic capsule defects. We conclude that retinoic acid coordinates inner ear morphogenesis by controlling an FGF/Dlx signaling cascade, whose perturbation by deviations in local retinoid concentrations can lead to inner ear dysmorphogenesis.

Frenz, Dorothy A.; Liu, Wei; Cvekl, Ales; Xie, Qing; Wassef, Lesley; Quadro, Loredana; Niederreither, Karen; Maconochie, Mark; Shanske, Alan

2010-01-01

325

Evaluating ear cartilage piercing practices in London, UK.  

PubMed

Background: Ear cartilage piercing is increasingly popular and has a significant complication rate. Contrary to popular belief, there are no minimum qualifications required to practice ear piercing. This study evaluated ear cartilage piercing practices in London, UK. Method: Practitioners at 25 piercing parlours completed a telephone questionnaire assessing piercing practice. Results: Ninety-six per cent of practitioners were aware of the risk of infection post-piercing. Four per cent, 12 per cent and 0 per cent of practitioners were aware of keloid scarring, hypertrophic scarring and cauliflower ear respectively. No practitioners were aware of any other complications. Their consent forms did not document any ear cartilage complications. Twenty-eight per cent of participants advised clients to seek medical attention following a complication. Forty per cent did not provide written post-piercing guidance. Conclusion: Piercing practitioners were insufficiently aware of ear cartilage piercing complications. It is unlikely that informed consent was obtained prior to piercing. The post-piercing practice of the majority of parlours did not follow published national guidance. PMID:24909453

Mandavia, R; Kapoor, K; Ouyang, J; Osmani, H

2014-06-01

326

Stimulus-dependent effects on right ear advantage in schizophrenia  

PubMed Central

Background When presented with different sounds in each ear (dichotic listening), healthy subjects typically show a preference for stimuli heard in the right ear, an effect termed “right ear advantage”. Previous studies examining right ear advantage in schizophrenia have been inconsistent, showing either decreased or increased advantage relative to comparison subjects. Given evidence for enhanced semantic processing in schizophrenia, some of this inconsistency may be due to the type of stimuli presented (words or syllables). The present study examined right ear advantage in patients and controls using both words and syllables as stimuli. Methods Right ear advantage was compared between 20 patients with schizophrenia and 17 healthy controls. Two versions of the task were used, ie, a consonant-vowel pairing task and a fused rhymed words task. Results A significant group × task interaction was observed. Relative to healthy controls, patients showed a greater difference on the syllable-based task compared with the word-based task. The number of distractors marked during the syllable-based task was inversely correlated with score on the Global Assessment of Function Scale. Conclusion The findings are consistent with a left hemisphere dysfunction in schizophrenia, but also suggest that differences may be stimulus-specific, with a relative sparing of the deficit in the context of word stimuli. Performance may be related to measures of social, occupational, and psychological function.

Smucny, Jason; Wylie, Korey; Tregellas, Jason

2012-01-01

327

Auditory Brainstem Circuits That Mediate the Middle Ear Muscle Reflex  

PubMed Central

The middle ear muscle (MEM) reflex is one of two major descending systems to the auditory periphery. There are two middle ear muscles (MEMs): the stapedius and the tensor tympani. In man, the stapedius contracts in response to intense low frequency acoustic stimuli, exerting forces perpendicular to the stapes superstructure, increasing middle ear impedance and attenuating the intensity of sound energy reaching the inner ear (cochlea). The tensor tympani is believed to contract in response to self-generated noise (chewing, swallowing) and nonauditory stimuli. The MEM reflex pathways begin with sound presented to the ear. Transduction of sound occurs in the cochlea, resulting in an action potential that is transmitted along the auditory nerve to the cochlear nucleus in the brainstem (the first relay station for all ascending sound information originating in the ear). Unknown interneurons in the ventral cochlear nucleus project either directly or indirectly to MEM motoneurons located elsewhere in the brainstem. Motoneurons provide efferent innervation to the MEMs. Although the ascending and descending limbs of these reflex pathways have been well characterized, the identity of the reflex interneurons is not known, as are the source of modulatory inputs to these pathways. The aim of this article is to (a) provide an overview of MEM reflex anatomy and physiology, (b) present new data on MEM reflex anatomy and physiology from our laboratory and others, and (c) describe the clinical implications of our research.

Mukerji, Sudeep; Windsor, Alanna Marie; Lee, Daniel J.

2013-01-01

328

Thiyl radical-induced cis-trans-isomerization of arachidonic acid inhibits prostaglandin metabolism  

NASA Astrophysics Data System (ADS)

Thiyl radicals isomerize the olefinic bonds of natural all- cis-polyunsaturated fatty acids into their trans-state. Using low doses of gamma-irradiation we partially converted arachidonic acid (AA) by thiyl radical attack into its mono- trans-forms. The enzyme-driven prostaglandin metabolism was studied in these samples in liquid model as well as in in vivo conditions with four different detection methods. A dramatic inhibition of the metabolism explained by blocking of the cyclooxygenase by trans-isomers has been found.

Kratzsch, S.; Drössler, K.; Sprinz, H.; Brede, Ortwin

2003-06-01

329

Arachidonic acid metabolism in the human placenta: Identification of a putative lipoxygenase.  

PubMed

Arachidonic acid (ARA) metabolites maintain pregnancy and control parturition. We generated a network of 77 proteins involved in placental ARA metabolism to identify novel proteins in this pathway. We identified a long pathway within this network which showed that secretory and cytosolic phospholipase A2 proteins act in concert. The functions of all network proteins expressed in the placental decidua were determined by database searches. Thus ARA metabolism was linked to carbohydrate metabolism. One protein, transmembrane protein 62 (TMEM62), expressed in decidua was previously uncharacterized, and was identified as a putative lipoxygenase. TMEM62 may play a role in pregnancy and/or parturition. PMID:24767823

Jadoon, A; Cunningham, P; McDermott, L C

2014-06-01

330

Arachidonic Acid and Other Fatty Acids Directly Activate Potassium Channels in Smooth Muscle Cells  

NASA Astrophysics Data System (ADS)

Arachidonic acid, as well as fatty acids that are not substrates for cyclooxygenase and lipoxygenase enzymes, activated a specific type of potassium channel in freshly dissociated smooth muscle cells. Activation occurred in excised membrane patches in the absence of calcium and all nucleotides. Therefore signal transduction pathways that require such soluble factors, including the NADPH-dependent cytochrome P450 pathway, do not mediate the response. Thus, fatty acids directly activate potassium channels and so may constitute a class of signal molecules that regulate ion channels.

Ordway, Richard W.; Walsh, John V.; Singer, Joshua J.

1989-06-01

331

Inhibition of mouse skin tumor promotion by several inhibitors of arachidonic acid metabolism  

SciTech Connect

12-O-Tetradecanoylphorbol-13-acetate promotion of skin tumors in mice can be inhibited by topical application of either the phospholipase A/sub 2/ inhibitor dibromoacetophenone or the cyclooxygenase-lipoxygenase inhibitors 5,8,11,14-eicosatetrayonic acid or 1-phenyl-3-pyrazolidinone. The phospholipase A/sub 2/ inhibitors in particular appear to be among the most potent inhibitors of skin tumor promotion known. These results support the hypothesis that at least some of the products of arachidonic acid transformation are essential for tumor promotion.

Fischer, S.M.; Mills, G.D.; Slaga, T.J.

1982-01-01

332

Arachidonate metabolism by human polymorphonuclear leukocytes stimulated by N-formyl-Met-Leu-Phe or complement component C5a is independent of phospholipase activation.  

PubMed Central

Release of arachidonic acid by the membrane phospholipase and metabolism by the 5-lipoxygenase pathway was examined in human polymorphonuclear leukocytes (PMNs). The 5-lipoxygenase pathway is activated when PMNs are given arachidonic acid in ethanol and there is extensive metabolism to 5-hydroxyicosatetraenoic acid (5-HETE) and leukotriene B4 (LTB4). This activation event was shown to be altered by the ethanol because resting PMNs given arachidonic acid with bovine serum albumin fail to metabolize arachidonic acid. However, cells activated by the inflammatory agents N-formyl-Met-Leu-Phe (fMLF) or complement component C5a recruit the 5-lipoxygenase to metabolize exogenous arachidonic acid to 5-HETE and LTB4. When PMNs were incubated with arachidonic acid-bovine serum albumin and challenged with fMLF or C5a (des-Arg-C5a) they produced 49-75 pmol of LTB4 and 310-440 pmol of 5-HETE per 10(7) cells. PMNs stimulated by fMLF or C5a (des-Arg-C5a) do not induce membrane phospholipases to mobilize endogenous arachidonic acid and neither 5-HETE nor LTB4 is formed. In contrast, PMN stimulation by the ionophore A23187 activates both the membrane phospholipase and the 5-lipoxygenase to produce 5-HETE and LTB4 from endogenous arachidonic acid. Our results indicate that the lipoxygenase pathway is inoperative in resting PMNs but can be recruited by chemotactic factors to act on arachidonate from extracellular sources. It was previously believed that formation of 5-HETE and LTB4 by the PMN depends solely on phospholipase to mobilize endogenous arachidonic acid. The results reported here refute this concept and indicate that the role of phospholipase activation in PMN may be overestimated. Therefore, subsequent involvement of lipoxygenase products in mediating stimulation of PMN by inflammatory factors (e.g., as in aggregation and chemotaxis) remains in question unless an exogenous source of arachidonate can be identified.

Clancy, R M; Dahinden, C A; Hugli, T E

1983-01-01

333

Imaging Finding of Malignant Melanoma of Eustachian Tube with Extension to Middle Ear Cavity: Case Report  

PubMed Central

We report a case of malignant melanoma of Eustachian tube with extension to the middle ear cavity and nasopharynx in a 51-year-old woman who presented with right ear fullness. Computed tomography showed a soft tissue mass in the middle ear cavity and causedthe widening and eroding of the bony eustachian tube. Magnetic resonance imaging showed well enhancing mass in eustachian tube extending nasopharynx to middle ear cavity. A biopsy of the middle ear cavity mass revealed a malignant amelanotic melanoma.

Kim, Hong Chul; Jang, Han Won

2012-01-01

334

Complex stapes motions in human ears.  

PubMed

It has been reported that the physiological motion of the stapes in human and several animals in response to acoustic stimulation is mainly piston-like at low frequencies. At higher frequencies, the pattern includes rocking motions around the long and short axes of the footplate in human and animal ears. Measurements of such extended stapes motions are highly sensitive to the exact angulation of the stapes in relation to the measurement devices and to measurement errors. In this study, velocity in a specific direction was measured at multiple points on the footplates of human temporal bones using a Scanning Laser Doppler Vibrometer (SLDV) system, and the elementary components of the stapes motions, which were the piston-like motion and the rocking motions about the short and long axes of the footplate, were calculated from the measurements. The angular position of a laser beam with respect to the stapes and coordinates of the measurement points on the footplate plane were calculated by correlation between the SLDV measurement frame and the footplate-fixed frame, which was obtained from micro-CT images. The ratios of the rocking motions relative to the piston-like motion increased with frequency and reached a maximum around 7 kHz.A novel method for quantitatively assessing measurements of complex stapes motions and error boundaries of the motion components is presented. In the frequency range of 0.5 to 8 kHz, the magnitudes of the piston-like and two rocking motions were larger than estimated values of the corresponding upper error bounds. PMID:20165895

Sim, Jae Hoon; Chatzimichalis, Michail; Lauxmann, Michael; Röösli, Christof; Eiber, Albrecht; Huber, Alexander M

2010-09-01

335

Linoleic acid supplementation results in increased arachidonic acid and eicosanoid production in CF airway cells and in cftr?/? transgenic mice  

PubMed Central

Cystic fibrosis (CF) patients display a fatty acid imbalance characterized by low linoleic acid levels and variable changes in arachidonic acid. This led to the recommendation that CF patients consume a high-fat diet containing >6% linoleic acid. We hypothesized that increased conversion of linoleic acid to arachidonic acid in CF leads to increased levels of arachidonate-derived proinflammatory metabolites and that this process is exacerbated by increasing linoleic acid levels in the diet. To test this hypothesis, we determined the effect of linoleic acid supplementation on downstream proinflammatory biomarkers in two CF models: 1) in vitro cell culture model using 16HBE14o? sense [wild-type (WT)] and antisense (CF) human airway epithelial cells; and 2) in an in vivo model using cftr?/? transgenic mice. Fatty acids were analyzed by gas chromatography-mass spectrometry (GC/MS), and IL-8 and eicosanoids were measured by ELISA. Neutrophils were quantified in bronchoalveolar lavage fluid from knockout mice following linoleic acid supplementation and exposure to aerosolized Pseudomonas LPS. Linoleic acid supplementation increased arachidonic acid levels in CF but not WT cells. IL-8, PGE2, and PGF2? secretion were increased in CF compared with WT cells, with a further increase following linoleic acid supplementation. cftr?/? Mice supplemented with 100 mg of linoleic acid had increased arachidonic acid levels in lung tissue associated with increased neutrophil infiltration into the airway compared with control mice. These findings support the hypothesis that increasing linoleic acid levels in the setting of loss of cystic fibrosis transmembrane conductance regulator (CFTR) function leads to increased arachidonic acid levels and proinflammatory mediators.

Zaman, Munir M.; Martin, Camilia R.; Andersson, Charlotte; Bhutta, Abdul Q.; Cluette-Brown, Joanne E.; Laposata, Michael

2010-01-01

336

Effects of the unsaturation of dietary fat and of arachidonate supplementation on cholesterol pool expansion in the guinea pigs.  

PubMed

We have studied the effects of methyl arachidonate supplementation on the lipid metabolism of guinea pigs fed cholesterol. Four groups of guinea pigs were fed a purified diet containing 9.5% hydrogenated coconut oil (HCNO), a highly saturated fat with or without the addition of 1% cholesterol, for 15 weeks. One half of the animals fed the control and the cholesterol-containing diets were supplemented with 15 mg methyl arachidonate three times per week. Supplementation with methyl arachidonate did not alter the concentration of plasma total (TC) or unesterified (FC) cholesterol, erythrocyte cholesterol and plasma phospholipid or the ratio of plasma FC/TC. Accumulation of cholesterol in the major organs of the cholesterol-fed groups was also unchanged. In both control and cholesterol-fed groups, methyl arachidonate decreased the proportion of oleic (18:1) and linoleic acids (18:2) and increased arachidonic acid (20:4) content of plasma and liver phospholipid. A comparison between the results of this study and studies using cottonseed oil showed that the type of dietary fat modifies the effects of cholesterol: plasma cholesterol levels were higher and liver cholesterol storage was lower in animals fed the saturated fat than in those fed the fat rich in polyunsaturated fatty acids (PUFA). Furthermore, in spite of similar changes in erythrocyte cholesterol content and shape abnormalities, no overt hemolytic anemia was observed in the groups fed cholesterol and saturated fat, in contrast to those fed cholesterol + PUFA-containing fat. We conclude that in guinea pigs supplementary methyl arachidonate had no hypocholesterolemic effect at the levels we fed, that circulating cholesterol levels are not a measure of cholesterol accumulation by organs and that the decrease of serum cholesterol in response of PUFA is due in part to an increase of cholesterol storage in the liver. PMID:448452

Crocker, P J; Fitch, M; Ostwald, R

1979-06-01

337

Glucocorticoids shift arachidonic acid metabolism toward endocannabinoid synthesis: a non-genomic anti-inflammatory switch  

PubMed Central

Glucocorticoids are capable of exerting both genomic and non-genomic actions in target cells of multiple tissues, including the brain, which trigger an array of electrophysiological, metabolic, secretory and inflammatory regulatory responses. Here, we have attempted to show how glucocorticoids may generate a rapid anti-inflammatory response by promoting arachidonic acid-derived endocannabinoid biosynthesis. According to our hypothesized model, non-genomic action of glucocorticoids results in the global shift of membrane lipid metabolism, subverting metabolic pathways toward the synthesis of the anti-inflammatory endocannabinoids, anandamide (AEA) and 2-arachidonoyl-glycerol (2-AG), and away from arachidonic acid production. Post-transcriptional inhibition of cyclooxygenase-2 (COX2) synthesis by glucocorticoids assists this mechanism by suppressing the synthesis of pro-inflammatory prostaglandins as well as endocannabinoid-derived prostanoids. In the central nervous system (CNS) this may represent a major neuroprotective system, which may cross-talk with leptin signaling in the hypothalamus allowing for the coordination between energy homeostasis and the inflammatory response.

Malcher-Lopes, Renato; Franco, Alier; Tasker, Jeffrey G.

2008-01-01

338

Percentage oleic acid is inversely related to percentage arachidonic acid in total lipids of rat serum  

PubMed Central

Background Since many health effects of oils rich in oleic acid (18:1, n-9) seem to be opposite those of arachidonic acid (20:4, n-6), i.e. concerning cardiovascular risk, we examined whether % 18:1 might be negatively associated with % 20:4. Methods Fatty acid separation by gas chromatography was performed in total serum lipids of 36 male rats. Using bivariate correlations and multiple linear regressions we studied the association between oleic acid and arachidonic acid. Results We found an inverse relationship (r?=?-0.885, p?

2013-01-01

339

Increase in class 2 aldehyde dehydrogenase expression by arachidonic acid in rat hepatoma cells.  

PubMed Central

Aldehyde dehydrogenase (ALDH) is a family of several isoenzymes important in cell defence against both exogenous and endogenous aldehydes. Compared with normal hepatocytes, in rat hepatoma cells the following changes in the expression of ALDH occur: cytosolic class 3 ALDH expression appears and mitochondrial class 2 ALDH decreases. In parallel with these changes, a decrease in the polyunsaturated fatty acid content in membrane phospholipids occurs. In the present study we demonstrated that restoring the levels of arachidonic acid in 7777 and JM2 rat hepatoma cell lines to those seen in hepatocytes decreases hepatoma cell growth, and increases class 2 ALDH activity. This latter effect appears to be due to an increased gene transcription of class 2 ALDH. To account for this increase, we examined whether peroxisome-proliferator-activated receptors (PPARs) or lipid peroxidation were involved. We demonstrated a stimulation of PPAR expression, which is different in the two hepatoma cell lines: in the 7777 cell line, there was an increase in PPAR alpha expression, whereas PPAR gamma expression increased in JM2 cells. We also found increased lipid peroxidation, but this increase became evident at a later stage when class 2 ALDH expression had already increased. In conclusion, arachidonic acid added to the culture medium of hepatoma cell lines is able to partially restore the normal phenotype of class 2 ALDH, in addition to a decrease in cell growth.

Canuto, R A; Ferro, M; Salvo, R A; Bassi, A M; Trombetta, A; Maggiora, M; Martinasso, G; Lindahl, R; Muzio, G

2001-01-01

340

Attachment of fatty acid substrate fragments to prostaglandin (PG) H synthase during reaction with arachidonate  

SciTech Connect

Pure ovine synthase was incubated aerobically with /sup 14/C-arachidonate to inactivate the cyclooxygenase. After solvent extraction to remove the bulk of the lipid, the inactive protein was analyzed by polyacrylamide gel electrophoresis. In SDS-PAGE radioactive label was associated with protein that comigrated with the 70 K Da synthase subunit, as well as with protein that accumulated at the upper edge of the resolving gel. In HPLC radioactivity was found in two peaks eluting in the region of unreacted synthase. SDS-PAGE analysis of pooled material from these HPLC peaks gave a distribution of radioactivity similar to that obtained with the unfractionated material. The radioactivity and protein content of inactivated synthase purified by HPLC indicated that 0.3-1.0 mole of substrate fragment were bound per mole of synthase subunit. Incubation of a mixture of the synthase and ovalbumin with arachidonate resulted in 5-fold more labelling of synthase than ovalbumin. Thus, a substrate fragment appears to become selectively attached to the synthase during reaction, and may represent the product of a self-inactivation event.

Kulmacz, R.J.

1987-05-01

341

Hydrocortisone selectively inhibits IgE-dependent arachidonic acid release from rat peritoneal mast cells  

SciTech Connect

Purified rat mst cells were used to study the effects of antiinflammatory steroids on the release of (1-14C)-arachidonic acid ((1-14C)AA) and metabolites. Mast cell were incubated overnight with glucocorticoids, (1-14C)AA incorporated into cellular phospholipids and the release of (1-14C)AA, and metabolites determined using a variety of secretagogues. Release of (1-14C)AA and metabolites by concanavalin A, the antigen ovalbumin and anti-immunoglobulin E antibody was markedly reduced by glucocorticoid treatment. Neither the total incorporation of (1-14C)AA nor the distribution into phospholipids was altered by hydrocortisone pretreatment. Glucocorticoid pretreatment did not alter (1-14C)AA release stimulated by somatostatin, compound 48/80, or the calcium ionophore, A23187. These data indicate that antiinflammatory steroids selectively inhibit immunoglobulin dependent release of arachidonic acid from rat mast cells. These findings question the role of lipomodulin and macrocortin as general phospholipase inhibitors and suggest that they may be restricted to immunoglobulin stimuli.

Heiman, A.S.; Crews, F.T.

1984-02-01

342

Endogenous biosynthesis of arachidonic acid epoxides in humans: increased formation in pregnancy-induced hypertension.  

PubMed Central

Arachidonic acid is metabolized by means of P450 isoenzyme(s) to form epoxyeicosatrienoic acids (EETs) and their corresponding dihydroxy derivatives (DHETs). In the present study, we established the presence in human urine of 8,9-, 11,12-, and 14,15-EETs and their corresponding DHETs by developing quantitative assays and using negative ion, chemical ionization GC/MS and octadeuterated internal standards. Urinary excretion of 8,9- and 11,12-DHET increased in healthy pregnant women compared with nonpregnant female volunteers. By contrast, excretion of 11,12-DHET and 14,15-DHET, but not the 8,9-DHET regioisomer, increased even further in patients with pregnancy-induced hypertension. Intravenous administration of [3H]14,15-EET to three dogs markedly increased its DHET in plasma. The terminal half-life ranged from 7.9-12.3 min and the volume of distribution (3.5-5.3 liters) suggested limited distribution outside the plasma compartment. Negligible radioactivity was detected in urine; this fact infers that under physiological circumstances, urinary DHETs largely derive from the kidney. That P450 metabolites of arachidonic acid are formed in humans supports the hypothesis that these metabolites contribute to the physiological response to normal pregnancy and the pathophysiology of pregnancy-induced hypertension.

Catella, F; Lawson, J A; Fitzgerald, D J; FitzGerald, G A

1990-01-01

343

[Synthesis of arachidonic acid cascade eicosanoids in tumors of various histogenesis in mice].  

PubMed

The investigation was undertaken to characterize the profile of arachidonic acid metabolites in different spontaneous and transplantable tumors in mice. The five metabolites via the cyclooxygenase pathway (PGE2, PGF2 alpha, PGD2, TxB2, 6-keto-PGF1 alpha), as well as the three lipoxygenase products (5-HETE, 12-HETE, and 15-HETE) were monitored by thin layer chromatography and high performance liquid chromatography after "ex vivo" metabolism of exogenous [1-C14]-arachidonic acid by homogenates of tumor tissues. It was shown that all tumors had a unique profile of eicosanoids. The most cyclooxygenase activity along with the significant synthesis of PGE2, PGF2 alpha, and 6-keto-PGF1 alpha was noted in lung tumors. The antitumor effect of indomethacin was directly related to the ability of tumors to produce PGE2. On the other hand, there were varying lipoxygenase activities in tumors. In some cases, the extremely high levels of 15- and 12-HETE synthesis in neoplastic tissue could indicate that there was a basic possibility of using lipoxygenase inhibitors for suppressing malignant tumors. PMID:7780341

Kudriavtsev, I A; Miasishcheva, N V

1995-01-01

344

Arachidonic acid metabolism and regulation of ion transport in rabbit Clara cells  

SciTech Connect

Sonicates of freshly isolated Clara cells produced thromboxane B2 (TxB2), prostaglandin (PG) D2, PGE2, PGF2 alpha, hydroxyheptadecatrienoic acid (HHT), and 12-hydroxyeicosatetraenoic acid (12-HETE) as detected using high-performance liquid chromatography (HPLC). Sonicates of Clara cells cultured on collagen matrices produced the same metabolites. Rates of (3H)arachidonic acid metabolism increased in culture, but the changes were not associated with changes in cell number. Sonicates of freshly isolated tracheal cells produced mainly 12-HETE. Cyclooxygenase products were not produced consistently. Sonicates of tracheal cultures produced significant quantities of TxB2, PGD2, PGE2, PGF2 alpha, and HHT, but 12-HETE remained the major metabolite. Equivalent short-circuit current (Ieq) across cultured Clara cell epithelia was unaffected by bilateral exposure to TxB2, PGD2, PGE2, PGF2 alpha, HHT, or 12-HETE. A minor (1%) decrease in transepithelial resistance (Rt) followed exposure to PGD2. Indomethacin had no significant effect on Rt or Ieq, but exposure of indomethacin-pretreated preparations to PGE2 revealed a minor (2%) increase in Ieq. In contrast, tracheal cell epithelia exhibited significant changes in Rt and Ieq in response to PGF2 alpha, PGE2, and HHT. These results indicate that Clara cells metabolize arachidonic acid to biologically active eicosanoids, but the resulting products do not play a major role in regulation of transepithelial ion transport by this cell type.

Van Scott, M.R.; McIntire, M.R.; Henke, D.C. (Univ. of North Carolina, Chapel Hill (USA))

1990-10-01

345

Arachidonate metabolism increases as rat alveolar type II cells differentiate in vitro  

SciTech Connect

Rat type II alveolar epithelial cells are known to undergo morphological and functional changes when maintained in culture for several days. Having previously demonstrated that these cells can deacylate free arachidonic acid (AA) and metabolize it to products of the cyclooxygenase pathway, the present study was undertaken to determine whether in vitro differentiation was accompanied by alterations in the availability and metabolism of AA. We assessed the constitutive and ionophore A23187-induced deacylation and metabolism of endogenous AA, as well as the metabolism of exogenously supplied AA, in primary cultures of rat type II cells at days 2, 4, and 7 after isolation. Levels of free endogenous AA were increased at day 4, whereas eicosanoid synthesis, predominantly prostaglandin E2 and prostacyclin, increased markedly only at day 7. A similar time course of augmentation of prostanoid release was seen in response to exogenous AA. Type II cells cultured on fibronectin, intended to hasten cell flattening and spreading, demonstrated accelerated increases in available free AA in response to A23187; cells cultured on basement membrane derived from Engelbreth-Holm-Swarm mouse sarcoma, known to maintain the type II phenotype, exhibited diminished levels of available free AA. From these findings, we conclude that alterations in arachidonate metabolism are linked to alterations in cellular phenotype. The potentiation of eicosanoid synthesis accompanying in vitro differentiation suggests a possible role for the alveolar epithelium in the modulation of inflammation and fibrosis in the distal lung.

Lipchik, R.J.; Chauncey, J.B.; Paine, R.; Simon, R.H.; Peters-Golden, M. (Univ. of Michigan, Ann Arbor (USA))

1990-08-01

346

Inhibitory effects of arachidonic acid on muscarinic current response in single pancreatic acinar cells of rats.  

PubMed

1. In single, enzymatically dissociated rat pancreatic acinar cells both acetylcholine (ACh) stimulation and IP3 (inositol 1,4,5-trisphosphate) injection evoke Ca2(+)-dependent transient responses. Exogenously applied arachidonic acid (AA) inhibits both responses in a dose-dependent manner. 2. Arachidonic acid oxidation inhibitors, indomethacin and nordihydroguaiaretic acid, cause no significant changes in ACh- and IP3-induced responses. The inhibitory effects of AA (50 microM) on IP3-induced responses are not influenced by the presence of these oxidation inhibitors. 3. An inhibitor of phospholipase A2 (PLA2), 4-bromophenacyl bromide (4-BPB; 10 microM), augments the ACh-induced response, and it potentiates the IP3-induced response by a factor of 10 to 20. The IP3-induced response, after its complete decay, is recovered by an administration of 4-BPB. 4. The results suggest that an increase in [Ca2+]i, induced by IP3 injection, activates PLA2, and that this resultant release of AA in turn inhibits IP3-dependent Ca2+ mobilization. PMID:2086771

Maruyama, Y

1990-11-01

347

Inhibitory effects of arachidonic acid on muscarinic current response in single pancreatic acinar cells of rats.  

PubMed Central

1. In single, enzymatically dissociated rat pancreatic acinar cells both acetylcholine (ACh) stimulation and IP3 (inositol 1,4,5-trisphosphate) injection evoke Ca2(+)-dependent transient responses. Exogenously applied arachidonic acid (AA) inhibits both responses in a dose-dependent manner. 2. Arachidonic acid oxidation inhibitors, indomethacin and nordihydroguaiaretic acid, cause no significant changes in ACh- and IP3-induced responses. The inhibitory effects of AA (50 microM) on IP3-induced responses are not influenced by the presence of these oxidation inhibitors. 3. An inhibitor of phospholipase A2 (PLA2), 4-bromophenacyl bromide (4-BPB; 10 microM), augments the ACh-induced response, and it potentiates the IP3-induced response by a factor of 10 to 20. The IP3-induced response, after its complete decay, is recovered by an administration of 4-BPB. 4. The results suggest that an increase in [Ca2+]i, induced by IP3 injection, activates PLA2, and that this resultant release of AA in turn inhibits IP3-dependent Ca2+ mobilization.

Maruyama, Y

1990-01-01

348

The effect of ozone exposure on rat alveolar macrophage arachidonic acid metabolism  

SciTech Connect

Rat alveolar macrophages were prelabeled with {sup 3}H-arachidonic acid ({sup 3}H-AA) and exposed to air or O3 (0.1-1.0 ppm) in vitro for 2 h. Alveolar macrophages released 3.6-fold more tritium at the 1.0 ppm exposure concentration compared with air-exposed macrophages. A significantly increased production of several {sup 3}H-AA metabolites, including 6-keto-PGF1 alpha, thromboxane B2, 12-hydroxy-5,8,10-heptadecatrienoic acid, prostaglandins E2 and D2, leukotrienes B4 and D4, and 15-hydroxyeicosatetraenoic acid was formed by macrophages exposed to 1.0 ppm O3 compared with air-exposed macrophages as determined by high performance liquid chromatography (HPLC) analysis. O3 exposure did not alter macrophage {sup 3}H-AA metabolism in response to calcium ionophore A23187. The largest tritiated peak observed in the HPLC chromatograms of O{sub 3}-exposed cells was a polar complex of products that contained various phospholipids and neutral lipids (including diacylglycerol) and possibly degradation products of {sup 3}H-AA and some of its metabolites. These changes in macrophage arachidonic acid metabolism may play an important role in the lung response to O{sub 3} exposure in vivo.

Madden, M.C.; Eling, T.E.; Dailey, L.A.; Friedman, M. (Univ. of North Carolina, Chapel Hill (USA))

1991-01-01

349

ARACHIDONIC ACID PRODUCTS IN AIRWAY NOCICEPTOR ACTIVATION DURING ACUTE LUNG INJURY  

PubMed Central

We have reported that airway nociceptors [C fiber receptors (CFRs) and high threshold A-delta fiber receptors (HTARs)] are activated during oleic acid (OA) induced acute lung injury. In the current studies, we tested the hypothesis that this nociceptor activation is mediated by arachidonic acid products. In anesthetized, open chest, and mechanically ventilated rabbits, we examined the response of the nociceptors to intravenous injection of OA before and after blocking the cyclo-oxygenase pathways by indomethacin. Pre-treatment with indomethacin (20 mg/kg) decreased the background activities of both CFRs (from 0.48±0.12 to 0.25±0.08, n=7, p<0.05) and HTARs (from 0.54±0.14 to 0.23±0.08, n=10, p<0.01). It also blocked the nociceptors’ response to OA. Similarly, pre-treatment with thromboxane synthase inhibitor (ketoconazole) also blocked the nociceptor response to OA. In addition, local microinjection or intravenous injection of a thromboxane mimetic stimulated CFRs and HTARs. The current results clearly indicate that arachidonic acid metabolites mediate airway nociceptor activation during OA-induced acute lung injury and suggest that thromboxane may be a key mediator.

Lin, Shuxin; Li, Huafeng; Xu, Ling; Moldoveanu, Bogdan; Guardiola, Juan; Yu, Jerry

2011-01-01

350

Heat shock protein 70-dependent protective effect of polaprezinc on acetylsalicylic acid-induced apoptosis of rat intestinal epithelial cells  

PubMed Central

Protection of the small intestine from mucosal injury induced by nonsteroidal anti-inflammatory drugs including acetylsalicylic acid is a critical issue in the field of gastroenterology. Polaprezinc an anti-ulcer drug, consisting of zinc and L-carnosine, provides gastric mucosal protection against various irritants. In this study, we investigated the protective effect of polaprezinc on acetylsalicylic acid-induced apoptosis of the RIE1 rat intestinal epithelial cell line. Confluent rat intestinal epithelial cells were incubated with 70 µM polaprezinc for 24 h, and then stimulated with or without 15 mM acetylsalicylic acid for a further 15 h. Subsequent cellular viability was quantified by fluorometric assay based on cell lysis and staining. Acetylsalicylic acid-induced cell death was also qualified by fluorescent microscopy of Hoechst33342 and propidium iodide. Heat shock proteins 70 protein expression after adding polaprezinc or acetylsalicylic acid was assessed by western blotting. To investigate the role of Heat shock protein 70, Heat shock protein 70-specific small interfering RNA was applied. Cell viability was quantified by fluorometric assay based on cell lysis and staining and apoptosis was analyzed by fluorescence-activated cell sorting. We found that acetylsalicylic acid significantly induced apoptosis of rat intestinal epithelial cells in a dose- and time-dependent manner. Polaprezinc significantly suppressed acetylsalicylic acid-induced apoptosis of rat intestinal epithelial cells at its late phase. At the same time, polaprezinc increased Heat shock protein 70 expressions of rat intestinal epithelial cells in a time-dependent manner. However, in Heat shock protein 70-silenced rat intestinal epithelial cells, polaprezinc could not suppress acetylsalicylic acid -induced apoptosis at its late phase. We conclude that polaprezinc-increased Heat shock protein 70 expression might be an important mechanism by which polaprezinc suppresses acetylsalicylic acid-induced small intestinal apoptosis, a hallmark of acetylsalicylic acid-induced enteropathy.

Qin, Ying; Naito, Yuji; Handa, Osamu; Hayashi, Natsuko; Kuki, Aiko; Mizushima, Katsura; Omatsu, Tatsushi; Tanimura, Yuko; Morita, Mayuko; Adachi, Satoko; Fukui, Akifumi; Hirata, Ikuhiro; Kishimoto, Etsuko; Nishikawa, Taichiro; Uchiyama, Kazuhiko; Ishikawa, Takeshi; Takagi, Tomohisa; Yagi, Nobuaki; Kokura, Satoshi; Yoshikawa, Toshikazu

2011-01-01

351

Photodynamic therapy using 5-aminolevulinic acid-induced photosensitization: current clinical status  

NASA Astrophysics Data System (ADS)

Photodynamic therapy using 5-aminolevulinic acid-induced photosensitization (ALA PDT) via endogenous protoporphyrin IX (PpIX) synthesis has been reported as efficacious, using topical formulations, in the treatment of a variety of dermatologic diseases including superficial basal cell carcinoma, Bowen's disease, and actinic (solar) keratoses. Application of ALA PDT to the detection and treatment of both malignant and non-malignant diseases of internal organs has recently been reported. Local internal application of ALA has been used for the detection, via PpIX fluorescence, of pathological conditions of the human urinary bladder and for selective endometrial ablation in animal model systems. Systemic, oral administration of ALA has been used for ALA PDT of superficial head and neck cancer and of colorectal cancer. This paper reviews the current clinical status of ALA PDT.

Marcus, Stuart L.; Golub, Allyn L.; Shulman, D. Geoffrey

1995-03-01

352

Photodynamic therapy using 5-aminolevulinic acid-induced photosensitization: current clinical status  

NASA Astrophysics Data System (ADS)

Photodynamic therapy using 5-aminolevulinic acid-induced photosensitization (ALA PDT) via endogenous protoporphyrin IX (PpIX) synthesis has been reported as efficacious, using topical formulations, in the treatment of a variety of dermatologic diseases including superficial basal cell carcinoma, Bowen's disease, and actinic (solar) keratoses. Application of ALA PDT to the detection and treatment of both malignant and non-malignant diseases of internal organs has recently been reported. Local internal application of ALA has been used for the detection, via PpIX fluorescence, of pathological conditions of the human urinary bladder and for selective endometrial ablation in animal model systems. Systemic, oral administration of ALA has been used for ALA PDT of superficial head and neck cancer and of colorectal cancer. This paper reviews the current clinical status of ALA PDT.

Marcus, Stuart L.; Golub, Allyn L.; Shulman, D. Geoffrey

1994-10-01

353

Transcriptional elongation factor elongin A regulates retinoic acid-induced gene expression during neuronal differentiation.  

PubMed

Elongin A increases the rate of RNA polymerase II (pol II) transcript elongation by suppressing transient pausing by the enzyme. Elongin A also acts as a component of a cullin-RING ligase that can target stalled pol II for ubiquitylation and proteasome-dependent degradation. It is not known whether these activities of Elongin A are functionally interdependent in vivo. Here, we demonstrate that Elongin A-deficient (Elongin A(-/-)) embryos exhibit abnormalities in the formation of both cranial and spinal nerves and that Elongin A(-/-) embryonic stem cells (ESCs) show a markedly decreased capacity to differentiate into neurons. Moreover, we identify Elongin A mutations that selectively inactivate one or the other of the aforementioned activities and show that mutants that retain the elongation stimulatory, but not pol II ubiquitylation, activity of Elongin A rescue neuronal differentiation and support retinoic acid-induced upregulation of a subset of neurogenesis-related genes in Elongin A(-/-) ESCs. PMID:23122963

Yasukawa, Takashi; Bhatt, Shachi; Takeuchi, Tamotsu; Kawauchi, Junya; Takahashi, Hidehisa; Tsutsui, Aya; Muraoka, Takuya; Inoue, Makoto; Tsuda, Masayuki; Kitajima, Shigetaka; Conaway, Ronald C; Conaway, Joan W; Trainor, Paul A; Aso, Teijiro

2012-11-29

354

Bile acids induce pancreatic acinar cell injury and pancreatitis by activating calcineurin.  

PubMed

Biliary pancreatitis is the leading cause of acute pancreatitis in both children and adults. A proposed mechanism is the reflux of bile into the pancreatic duct. Bile acid exposure causes pancreatic acinar cell injury through a sustained rise in cytosolic Ca(2+). Thus, it would be clinically relevant to know the targets of this aberrant Ca(2+) signal. We hypothesized that the Ca(2+)-activated phosphatase calcineurin is such a Ca(2+) target. To examine calcineurin activation, we infected primary acinar cells from mice with an adenovirus expressing the promoter for a downstream calcineurin effector, nuclear factor of activated T-cells (NFAT). The bile acid taurolithocholic acid-3-sulfate (TLCS) was primarily used to examine bile acid responses. TLCS caused calcineurin activation only at concentrations that cause acinar cell injury. The activation of calcineurin by TLCS was abolished by chelating intracellular Ca(2+). Pretreatment with 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (acetoxymethyl ester) (BAPTA-AM) or the three specific calcineurin inhibitors FK506, cyclosporine A, or calcineurin inhibitory peptide prevented bile acid-induced acinar cell injury as measured by lactate dehydrogenase leakage and propidium iodide uptake. The calcineurin inhibitors reduced the intra-acinar activation of chymotrypsinogen within 30 min of TLCS administration, and they also prevented NF-?B activation. In vivo, mice that received FK506 or were deficient in the calcineurin isoform A? (CnA?) subunit had reduced pancreatitis severity after infusion of TLCS or taurocholic acid into the pancreatic duct. In summary, we demonstrate that acinar cell calcineurin is activated in response to Ca(2+) generated by bile acid exposure, bile acid-induced pancreatic injury is dependent on calcineurin activation, and calcineurin inhibitors may provide an adjunctive therapy for biliary pancreatitis. PMID:23148215

Muili, Kamaldeen A; Wang, Dong; Orabi, Abrahim I; Sarwar, Sheharyar; Luo, Yuhuan; Javed, Tanveer A; Eisses, John F; Mahmood, Syeda M; Jin, Shunqian; Singh, Vijay P; Ananthanaravanan, Meena; Perides, George; Williams, John A; Molkentin, Jeffery D; Husain, Sohail Z

2013-01-01

355

Bile Acids Induce Pancreatic Acinar Cell Injury and Pancreatitis by Activating Calcineurin*  

PubMed Central

Biliary pancreatitis is the leading cause of acute pancreatitis in both children and adults. A proposed mechanism is the reflux of bile into the pancreatic duct. Bile acid exposure causes pancreatic acinar cell injury through a sustained rise in cytosolic Ca2+. Thus, it would be clinically relevant to know the targets of this aberrant Ca2+ signal. We hypothesized that the Ca2+-activated phosphatase calcineurin is such a Ca2+ target. To examine calcineurin activation, we infected primary acinar cells from mice with an adenovirus expressing the promoter for a downstream calcineurin effector, nuclear factor of activated T-cells (NFAT). The bile acid taurolithocholic acid-3-sulfate (TLCS) was primarily used to examine bile acid responses. TLCS caused calcineurin activation only at concentrations that cause acinar cell injury. The activation of calcineurin by TLCS was abolished by chelating intracellular Ca2+. Pretreatment with 1,2-bis(o-aminophenoxy)ethane-N,N,N?,N?-tetraacetic acid (acetoxymethyl ester) (BAPTA-AM) or the three specific calcineurin inhibitors FK506, cyclosporine A, or calcineurin inhibitory peptide prevented bile acid-induced acinar cell injury as measured by lactate dehydrogenase leakage and propidium iodide uptake. The calcineurin inhibitors reduced the intra-acinar activation of chymotrypsinogen within 30 min of TLCS administration, and they also prevented NF-?B activation. In vivo, mice that received FK506 or were deficient in the calcineurin isoform A? (CnA?) subunit had reduced pancreatitis severity after infusion of TLCS or taurocholic acid into the pancreatic duct. In summary, we demonstrate that acinar cell calcineurin is activated in response to Ca2+ generated by bile acid exposure, bile acid-induced pancreatic injury is dependent on calcineurin activation, and calcineurin inhibitors may provide an adjunctive therapy for biliary pancreatitis.

Muili, Kamaldeen A.; Wang, Dong; Orabi, Abrahim I.; Sarwar, Sheharyar; Luo, Yuhuan; Javed, Tanveer A.; Eisses, John F.; Mahmood, Syeda M.; Jin, Shunqian; Singh, Vijay P.; Ananthanaravanan, Meena; Perides, George; Williams, John A.; Molkentin, Jeffery D.; Husain, Sohail Z.

2013-01-01

356

Platelets induce endothelial tissue factor expression in a mouse model of acid-induced lung injury.  

PubMed

Although the lung expresses procoagulant proteins under inflammatory conditions, underlying mechanisms remain unclear. Here, we addressed lung endothelial expression of tissue factor (TF), which initiates the coagulation cascade and expression of which signifies development of a procoagulant phenotype in the vasculature. To establish the model of acid-induced acute lung injury (ALI), we intranasally instilled anesthetized mice with saline or acid. Then 2 h later, we isolated pulmonary vascular cells for flow cytometry and confocal microscopy to detect the leukocyte antigen, CD45 and the endothelial markers VE-cadherin and von Willebrand factor (vWf). Acid increased both the number of vWf-expressing cells as well as TF and P-selectin expressions on these cells. All of these effects were markedly inhibited by treating mice with antiplatelet serum, suggesting the involvement of platelets. The increased expressions of TF, vWf, and P-selectin in response to acid also occurred in platelets. Moreover, the effects were replicated in endothelial cells derived from isolated, blood-perfused lungs. However, the effect was inhibited completely in lungs perfused with platelet-depleted and, to a lesser extent, with leukocyte-depleted blood. Acid injury increased endothelial expressions of the platelet proteins, CD41 and CD42b, providing evidence that platelet proteins were transferred to the vascular surface. Reactive oxygen species (ROS) were implicated in these responses, in that the endothelial and platelet protein expressions were inhibited. We conclude that acid-induced ALI causes NOX2-mediated ROS generation that activates platelets, which then generate a procoagulant endothelial surface. PMID:22505671

Emin, Memet T; Sun, Li; Huertas, Alice; Das, Shonit; Bhattacharya, Jahar; Bhattacharya, Sunita

2012-06-01

357

Endothelial connexin43 mediates acid-induced increases in pulmonary microvascular permeability.  

PubMed

Acid aspiration, a common cause of acute lung injury, leads to alveolar edema. Increase in lung vascular permeability underlies this pathology. To define mechanisms, isolated rat lungs were perfused with autologous blood. Hydrochloric acid and rhodamine-dextran 70 kDa (RDx70) were coinstilled into an alveolus by micropuncture. RDx70 fluorescence was used to establish the spatial distribution of acid. Subsequently, FITC-dextran 20 kDa (FDx20) was infused into microvessels for 60 min followed by a 10-min HEPES-buffered saline wash. During the infusion, FITC fluorescence changes were recorded to quantify the ratio of peak to postwash fluorescence. The ratio, termed normalized fluorescence, was low for acid compared with buffer instillation both in microvessels abutting acid-treated alveoli and those located more than 700 ?m away. In contrast, the normalized fluorescence was similar to buffer controls when a higher molecular weight tracer (FITC-dextran 70 kDa) was infused instead of FDx20, suggesting that normalized FDx20 fluorescence faithfully represented microvascular permeability. Inhibiting endothelial connexin43 (Cx43) gap junction communication with Gap27 blunted the acid-induced reduction in normalized fluorescence, although scrambled Gap27 did not have any effect. The blunting was evident not only in microvessels away from the site of injury, but also in those abutting directly injured alveoli. Thus the new fluorescence-based method reveals that acid increases microvascular permeability both at acid-instilled and away sites. Inhibiting endothelial Cx43 blocked the permeability increase even at the direct injury sites. These data indicate for the first time that Cx43-dependent mechanisms mediate acid-induced increases in microvascular permeability. Cx43 may be a therapeutic target in acid injury. PMID:22561459

Parthasarathi, Kaushik

2012-07-01

358

Endothelial connexin43 mediates acid-induced increases in pulmonary microvascular permeability  

PubMed Central

Acid aspiration, a common cause of acute lung injury, leads to alveolar edema. Increase in lung vascular permeability underlies this pathology. To define mechanisms, isolated rat lungs were perfused with autologous blood. Hydrochloric acid and rhodamine-dextran 70 kDa (RDx70) were coinstilled into an alveolus by micropuncture. RDx70 fluorescence was used to establish the spatial distribution of acid. Subsequently, FITC-dextran 20 kDa (FDx20) was infused into microvessels for 60 min followed by a 10-min HEPES-buffered saline wash. During the infusion, FITC fluorescence changes were recorded to quantify the ratio of peak to postwash fluorescence. The ratio, termed normalized fluorescence, was low for acid compared with buffer instillation both in microvessels abutting acid-treated alveoli and those located more than 700 ?m away. In contrast, the normalized fluorescence was similar to buffer controls when a higher molecular weight tracer (FITC-dextran 70 kDa) was infused instead of FDx20, suggesting that normalized FDx20 fluorescence faithfully represented microvascular permeability. Inhibiting endothelial connexin43 (Cx43) gap junction communication with Gap27 blunted the acid-induced reduction in normalized fluorescence, although scrambled Gap27 did not have any effect. The blunting was evident not only in microvessels away from the site of injury, but also in those abutting directly injured alveoli. Thus the new fluorescence-based method reveals that acid increases microvascular permeability both at acid-instilled and away sites. Inhibiting endothelial Cx43 blocked the permeability increase even at the direct injury sites. These data indicate for the first time that Cx43-dependent mechanisms mediate acid-induced increases in microvascular permeability. Cx43 may be a therapeutic target in acid injury.

2012-01-01

359

Human ear detection in the thermal infrared spectrum  

NASA Astrophysics Data System (ADS)

In this paper the problem of human ear detection in the thermal infrared (IR) spectrum is studied in order to illustrate the advantages and limitations of the most important steps of ear-based biometrics that can operate in day and night time environments. The main contributions of this work are two-fold: First, a dual-band database is assembled that consists of visible and thermal profile face images. The thermal data was collected using a high definition middle-wave infrared (3-5 microns) camera that is capable of acquiring thermal imprints of human skin. Second, a fully automated, thermal imaging based ear detection method is developed for real-time segmentation of human ears in either day or night time environments. The proposed method is based on Haar features forming a cascaded AdaBoost classifier (our modified version of the original Viola-Jones approach1 that was designed to be applied mainly in visible band images). The main advantage of the proposed method, applied on our profile face image data set collected in the thermal-band, is that it is designed to reduce the learning time required by the original Viola-Jones method from several weeks to several hours. Unlike other approaches reported in the literature, which have been tested but not designed to operate in the thermal band, our method yields a high detection accuracy that reaches ~ 91.5%. Further analysis on our data set yielded that: (a) photometric normalization techniques do not directly improve ear detection performance. However, when using a certain photometric normalization technique (CLAHE) on falsely detected images, the detection rate improved by ~ 4%; (b) the high detection accuracy of our method did not degrade when we lowered down the original spatial resolution of thermal ear images. For example, even after using one third of the original spatial resolution (i.e. ~ 20% of the original computational time) of the thermal profile face images, the high ear detection accuracy of our method remained unaffected. This resulted also in speeding up the detection time of an ear image from 265 to 17 milliseconds per image. To the best of our knowledge this is the first time that the problem of human ear detection in the thermal band is being investigated in the open literature.

Abaza, Ayman; Bourlai, Thirimachos

2012-05-01

360

Finite element modeling of energy absorbance in normal and disordered human ears.  

PubMed

The finite element (FE) model of the human ear has been developed to analyze the middle ear and cochlea function in relation to the ear structures. However, the energy absorbance or energy reflectance used in the research and clinical audiology test has not been reported in the FE model. The relationship between the middle ear structure and the energy absorbance (EA) needs to be identified using the FE model. In this study, a FE model of the human ear, including the ear canal, the middle ear and the spiral cochlea constructed from the histological sections of a human temporal bone, was used to calculate EA. The viscoelastic material properties were applied to the middle ear soft tissues. Three middle ear disorders were simulated in the FE model: otitis media, otosclerosis, and ossicular chain disarticulation. Multi-physics (acoustic, structure, and fluid) coupled analysis was conducted in the model. The FE model was first validated with the published experimental data on the middle ear input impedance and EA of the normal ear. The EA in three disordered ears was obtained from the model and compared with the published results measured in the clinics and the temporal bone experiments. The consistence of the model-derived EA with the published data demonstrates that the FE model is feasible to analyze EA. The effects of middle ear pressure, middle ear effusion, and mechanical properties of soft tissues on EA were estimated and discussed. This article is part of a special issue entitled "MEMRO 2012". PMID:23274858

Zhang, Xiangming; Gan, Rong Z

2013-07-01

361

Anisotropic yield function capable of predicting eight ears  

NASA Astrophysics Data System (ADS)

Deep drawing of a cylindrical cup from a rolled sheet is one of the typical forming operations where the effect of this anisotropy is most evident. Indeed, it is well documented in the literature that the number of ears and the shape of the earing pattern correlate with the r-values profile. For the strongly textured aluminum alloy AA 5042 (Numisheet Benchmark 2011), the experimental r-value distribution has two minima between the rolling and transverse direction data provided for this show that the r-value along the transverse direction (TD) is five times larger than the value corresponding to the rolling direction. Therefore, it is expected that there are more that the earing profile has more than four ears. The main objective of this paper is to assess whether a new form of CPB06ex2 yield function (Plunkett et al. (2008)) tailored for metals with no tension-compression asymmetry is capable of predicting more than four ears for this material.

Yoon, J. H.; Cazacu, O.

2011-08-01

362

Mycological and histological investigations in humans with middle ear infections.  

PubMed

The aim of our investigations was to characterize fungal colonization of the ear in immunocompetent patients. From 1993 to 2000, 128 patients supposed to suffer from otomycosis were included. Mycological examination conducted by direct microscopy and fungal cultures was performed on 139 specimens. Among these, 115 patients suffered from chronic otitis media with persisting tympanum perforation and otorrhea. A further 13 patients had clinical signs of an otitis externa only. Out of 139 samples, fungi were identified in the auditory canal (n = 54), on the tympanic membrane (n = 5), and in the middle ear (n = 5). Two-thirds were as moulds and one-third yeasts. The dominating species were Aspergillus niger and Candida parapsilosis. Samples from 15 patients supposed to have mastoiditis or cholesteatoma were examined histologically. Fungal hyphae were observed in the middle ear cavity and/or between horny lamellae of cholesteatoma in four patients. In the middle ear of immunocompetent patients chronic-hyperplastic (polypoid) inflammation was detected with increased production of mucus, which probably promotes colonization by pathogenic fungi in the middle ear as well as in the auditory canal. Invasive fungal growth into the subepithelial connective tissue was not observed. PMID:12588477

Vennewald, I; Schönlebe, J; Klemm, E

2003-02-01

363

[Keloid scars of the external ear: a non solved problem].  

PubMed

The external ear is a location with high risk of keloid scar formation. Its incidence is growing since general use of piercings and performance of plastic surgery of the external ear. The external ear keloid can be a devasting process for adolescent population which is worried about their appearance. Our aim is to attract attention about the risk of keloid scars of the external ear, reviewing our experience. After dismissing radiotherapy, corticoid infiltration and surgical removal are the most used options, with a high recurrence risk. We have reviewed traumatic, surgical and piercing wounds of the external ear, with a subsequent keloid formation treated in our outpatient clinic, collecting data about wound etiology, treatment and results. During the last 10 years we have found 11 keloid scars, 2 of them improved with topical corticosteroid. Treatment has been surgical in 9 cases, 4 of them with skin graft: 5 recovered and 4 recurred; 2 of them were reoperated. 2 of them were treated with intralesional corticosteroid solely, one recovered and the other one had improved. Treatment management of keloid scars is complex and there isn't a procedure with superior results than the others. Risk of complication must be explained within adolescent population. PMID:24783642

Bejarano Serrano, M; Parri Ferrandis, F J; García Smith, N I; Martínez-Herrada, S; Manzanares Quintela, A; Albert Cazalla, A

2014-01-01

364

Twelve oxo-eicosatetraenoic acid induces fetal membrane release after delivery in cows.  

PubMed

Fetal fibroblast cell culture from cotyledons of bovine placenta and animal experiments close to term were used to elucidate afterbirth release and factors missing in the signal transduction mechanism for retained fetal membranes (RFM) after delivery. In cell culture the addition of arachidonic acid (Ara) to the medium caused rapid release to free floating cell in the culture dish, accompanied by matrix metalloproteinase (MMP) activation, being consistent with previous in vivo observations, where a relation between MMP and fetal membrane release had been shown. Ara-induced cell floating was not inhibited by the addition of cyclooxygenase (COX) inhibitor, and not induced by the addition of PGF2? or PGE2 to replace Ara, while 12-lipoxygenase (12-LOX) metabolite of Ara, 12-oxo-eicosatetraenoic acid (12-oxoETE), strongly induced cell floating. In the animal experiments, 12-oxoETE injection to delivery-induced cows (n = 6) using prostaglandin (PG) and dexamethazone resulted in rapid release of fetal membranes. In cows with natural calf delivery, a 12-oxoETE peak (11.7-16.8 ng/ml) was observed in maternal blood plasma prior to release of fetal membranes. This investigation thus gives new indications for that the mediator for fetal membrane release is 12-oxoETE and not PG. PMID:22118869

Kamada, H; Matsui, Y; Sakurai, Y; Tanigawa, T; Itoh, M; Kawamoto, S; Kai, K; Sasaki, T; Takahashi, K; Hayashi, M; Takayama, Y; Nakamura, M; Kadokawa, H; Ueda, Y; Sutoh, M; Murai, M

2012-02-01

365

Ear-canal acoustic admittance and reflectance measurements in human neonates. II. Predictions of middle-ear dysfunction and sensorineural hearing loss  

NASA Astrophysics Data System (ADS)

This report describes relationships between middle-ear measurements of acoustic admittance and energy reflectance (YR) and measurements of hearing status using visual reinforcement audiometry in a neonatal hearing-screening population. Analyses were performed on 2638 ears in which combined measurements were obtained [Norton et al., Ear Hear. 21, 348-356 (2000)]. The measurements included distortion-product otoacoustic emissions (DPOAE), transient evoked otoacoustic emissions (TEOAE), and auditory brainstem responses (ABR). Models to predict hearing status using DPOAEs, TEOAEs, or ABRs were each improved by the addition of the YR factors as interactions, in which factors were calculated using factor loadings from Keefe et al. [J. Acoust. Soc. Am. 113, 389-406 (2003)]. This result suggests that information on middle-ear status improves the ability to predict hearing status. The YR factors were used to construct a middle-ear dysfunction test on 1027 normal-hearing ears in which DPOAE and TEOAE responses were either both present or both absent, the latter condition being viewed as indicative of middle-ear dysfunction. The middle-ear dysfunction test classified these ears with a nonparametric area (A) under the relative operating characteristic curve of A=0.86, and classified normal-hearing ears that failed two-stage hearing-screening tests with areas A=0.84 for DPOAE/ABR, and A=0.81 for TEOAE/ABR tests. The middle-ear dysfunction test adequately generalized to a new sample population (A=0.82).

Keefe, Douglas H.; Gorga, Michael P.; Neely, Stephen T.; Zhao, Fei; Vohr, Betty R.

2003-01-01

366

Transient retinoic acid signaling confers anterior-posterior polarity to the inner ear.  

PubMed

Vertebrate hearing and balance are based in complex asymmetries of inner ear structure. Here, we identify retinoic acid (RA) as an extrinsic signal that acts directly on the ear rudiment to affect its compartmentalization along the anterior-posterior axis. A rostrocaudal wave of RA activity, generated by tissues surrounding the nascent ear, induces distinct responses from anterior and posterior halves of the inner ear rudiment. Prolonged response to RA by posterior otic tissue correlates with Tbx1 transcription and formation of mostly nonsensory inner ear structures. By contrast, anterior otic tissue displays only a brief response to RA and forms neuronal elements and most sensory structures of the inner ear. PMID:21173260

Bok, Jinwoong; Raft, Steven; Kong, Kyoung-Ah; Koo, Soo Kyung; Dräger, Ursula C; Wu, Doris K

2011-01-01

367

[Middle ear deafness and noise trauma. Animal studies with the surface specimen technique (author's transl)].  

PubMed

The pertinent clinical literature concerning the research project is reviewed. The middle ear of guinea pigs was first damaged on one side (inflicting a subtotal perforation of the tympanic membrane, dislocation of the incudo-stapedial joint followed by otitis media) and the animals were then exposed to a specified narrow-band noise. The induced inner ear changes were quantified by means of cochleographic studies using the surface specimen technique. In spite of the inner ear changes due to middle ear manipulation prior to the noise exposure, the cochleographic studies revealed an obvious protective effect of the induced middle ear changes upon the inner ear during noise exposure. PMID:138031

Leidenfrost, U

1976-12-01

368

Acute doxorubicin cardiotoxicity alters cardiac cytochrome P450 expression and arachidonic acid metabolism in rats.  

PubMed

Doxorubicin (DOX) is a potent anti-neoplastic antibiotic used to treat a variety of malignancies; however, its use is limited by dose-dependent cardiotoxicity. Moreover, there is a strong correlation between cytochrome P450 (CYP)-mediated arachidonic acid metabolites and the pathogenesis of many cardiovascular diseases. Therefore, in the current study, we have investigated the effect of acute DOX toxicity on the expression of several CYP enzymes and their associated arachidonic acid metabolites in the heart of male Sprague-Dawley rats. Acute DOX toxicity was induced by a single intraperitoneal injection of 15 mg/kg of the drug. Our results showed that DOX treatment for 24 h caused a significant induction of CYP1A1, CYP1B1, CYP2C11, CYP2J3, CYP4A1, CYP4A3, CYP4F1, CYP4F4, and EPHX2 gene expression in the heart of DOX-treated rats as compared to the control. Similarly, there was a significant induction of CYP1A1, CYP1B1, CYP2C11, CYP2J3, CYP4A, and sEH proteins after 24 h of DOX administration. In the heart microsomes, acute DOX toxicity significantly increased the formation of 20-HETE which is consistent with the induction of the major CYP omega-hydroxylases: CYP4A1, CYP4A3, CYP4F1, and CYP4F4. On the other hand, the formation of 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acids (EETs) was significantly reduced, whereas the formation of their corresponding dihydroxyeicosatrienoic acids was significantly increased. The decrease in the cardioprotective EETs can be attributed to the increase of sEH activity parallel to the induction of the EPHX2 gene expression in the heart of DOX-treated rats. In conclusion, acute DOX toxicity alters the expression of several CYP and sEH enzymes with a consequent alteration in arachidonic acid metabolism. These results may represent a novel mechanism by which this drug causes progressive cardiotoxicity. PMID:19796650

Zordoky, Beshay N M; Anwar-Mohamed, Anwar; Aboutabl, Mona E; El-Kadi, Ayman O S

2010-01-01

369

Influences on clinical practice: the case of glue ear.  

PubMed

A case study of clinical practice in children with glue ear is presented. The case is part of a larger project, funded by the North Thames Research and Development Programme, that sought to explore the part played by clinicians in the implementation of research and development into practice in two areas: adult asthma and glue ear in children. What is striking about this case is the differences found in every area of the analysis. That is, diversity was found in views about diagnosis and treatment of glue ear; the organisation of related services; and in the reported practice of our interviewees, both between particular groupings of clinical staff and within these groupings. The challenge inherent in the case is to go beyond describing the complexity and differences that were found, and look for patterns in the accounts of practice and tease out why such patterns may occur. PMID:10557674

Dopson, S; Miller, R; Dawson, S; Sutherland, K

1999-06-01

370

A Ubiquitous Blood Pressure Sensor Worn at the Ear  

NASA Astrophysics Data System (ADS)

Blood pressure (BP) measurement and BP control are important for the prevention of lifestyle diseases, especially hypertension, which can lead to more serious conditions, such as cardiac infarction and cerebral apoplexy. The purpose of our study is to develop a ubiquitous blood pressure sensor that is more comfortable and less disruptive of users’ daily activities than conventional blood pressure sensors. Our developed sensor is worn at an ear orifice and measures blood pressure at the tragus. This paper describes the concept, configuration, and the optical and electronic details of the developed ear-worn blood pressure sensor and presents preliminary evaluation results. The developed sensor causes almost no discomfort and produces signals whose quality is high enough for detecting BP at an ear, making it suitable for ubiquitous usage.

Koizumi, Hiroshi; Shimada, Junichi; Uenishi, Yuji; Tochikubo, Osamu

2009-12-01

371

Human Action Recognition Using Wireless Wearable In-Ear Microphone  

NASA Astrophysics Data System (ADS)

To realize the ubiquitous eating habits monitoring, we proposed the use of sounds sensed by an in-ear placed wireless wearable microphone. A prototype of wireless wearable in-ear microphone was developed by utilizing a common Bluetooth headset. We proposed a robust chewing action recognition algorithm which consists of two recognition stages: “chew-like” signal detection and chewing sound verification stages. We also provide empirical results on other action recognition using in-ear sound including swallowing, cough, belch, and etc. The average chewing number counting error rate of 1.93% is achieved. Lastly, chewing sound mapping is proposed as a new prototypical approach to provide an additional intuitive feedback on food groups to be able to infer the eating habits in their daily life context.

Nishimura, Jun; Kuroda, Tadahiro

372

External ear transfer function modeling: a beamforming approach.  

PubMed

In this article, a beamformer is proposed as a functional model for the spatial and temporal filtering characteristics of the external ear. The output of a beamformer is a weighted combination of the data received at an array of spatially distributed sensors. The beamformer weights and array geometry determine its spatial and temporal filtering characteristics. A procedure is described for choosing the weights to minimize the mean-squared error between the beamformer response and the measured response of the external ear. The effectiveness of the model is demonstrated by designing a beamformer of several hundred weights that duplicates and interpolates the measured external ear response of a cat over broad ranges of frequency and direction. A limited investigation of modeling performance as a function of array geometry is reported. PMID:1401538

Chen, J; Van Veen, B D; Hecox, K E

1992-10-01

373

Role of arachidonic acid metabolism in transcriptional induction of tumor necrosis factor gene expression by phorbol ester  

SciTech Connect

The treatment of human HL-60 promyelocytic leukemia cells with 12-0 tetradecanoylphorbol-13-acetate (TPA) is associated with induction of tumor necrosis factor (TNF) transcripts. The study reported here has examined TPA-induced signaling mechanisms responsible for the regulation of TNF gene expression in these cells. Run-on assays demonstrated that TPA increases TNS mRNA levels by transcriptional activation of this gene. The induction of TNF transcripts by TPA was inhibited by the isoquinolinesulfonamide derivative H7 but not by HA1004, suggesting that this effect of TPA is mediated by activation of protein kinase C. TPA treatment also resulted in increased arachidonic acid release. Moreover, inhibitors of phospholipase, A/sub 2/ blocked both the increase in arachidonic acid release and the induction of TNF transcripts. These findings suggest that TPA induces TNF gene expression through the formation of arachidonic acid metabolites. Although indomethacin had no detectable effect on this induction of TNF transcripts, ketoconazole, an inhibitor of 5-lipoxygenase, blocked TPA-induced increases in TNF mRNA levels. Moreover, TNF mRNA levels were increased by the 5-lipoxygenase metabolite leukotriene B/sub 4/. In contrast, the cyclooxygenase metabolite prostaglandin E/sub 2/ inhibited the induction of TNF transcripts by TPA. Taken together, these results suggest that TPA induces TNF gene expression through the arachidonic acid cascade and that the level of TNF transcripts is regulated by metabolites of the pathway, leukotriene B/sub 4/ and prostaglandin E/sub 2/.

Horiguchi, J.; Spriggs, D.; Imamura, K.; Stone, R.; Luebbers, R.; Kufe, D.

1989-01-01

374

Mechanism for release of arachidonic acid during guinea pig platelet aggregation: a role for the diacylglycerol lipase inhibitor RHC 80267  

SciTech Connect

The mechanism of the release of arachidonic acid from phospholipids after the stimulation of guinea pig platelets with collagen, thrombin and platelet activating factor (PAF) was studied. RHC 80267, a diacylglycerol lipase inhibitor, and indomethacin, a cyclooxygenase inhibitor, were used. Various in vitro assays for enzymes involved in arachidonic acid release and metabolism were conducted. Platelet aggregation and simultaneous release of ADP from platelets were monitored using a Chrono-log Lumiaggregometer. Platelets were labeled with (/sup 14/C)arachidonic acid to facilitate sensitive determination of small changes in platelet phospholipids during platelet aggregation. In the present investigation it is shown that collagen, thrombin and PAF increased phospholipase C activity. It was also discovered that cyclooxygenase products were responsible for further stimulation (a positive feed-back) of phospholipase C activity, while diacylglycerol provided a negative feed-back control over receptor-stimulated phospholipase C activity and inhibited ADP release. The guinea pig platelet is an ideal model to study phospholipase C-diacylglycerol lipase pathway for the release of arachidonic acid from platelet phospholipids because it does not have any phospholipase A/sub 2/ activity. It was observed that cyclooxygenase products were responsible for collagen-induced guinea pig platelet aggregation. Indomethacin completely inhibited collagen-induced platelet aggregation, was less effective against thrombin, and had no effect on PAF-induced platelet aggregation. On the other hand, RHC 80267 was a powerful inhibitor of aggregation and ADP release induced by all three of these potent aggregating agents.

Amin, D.

1986-01-01

375

Safety evaluation of sources of docosahexaenoic acid and arachidonic acid for use in infant formulas in newborn piglets  

Microsoft Academic Search

Human milk provides small quantities of preformed docosahexaenoic acid (DHA) and arachidonic acid (ARA), usually less than 1% of total fatty acids. Vegetable oil blends commonly used in infant formulas have, until recently, provided the essential fatty acid precursors for these long-chain polyunsaturated fatty acids (LCPUFA), but no preformed DHA and ARA. This study evaluated the safety of ingredient sources

Russell J Merritt; Nancy Auestad; Claire Kruger; Sally Buchanan

2003-01-01

376

CO-EXPOSURE OF HUMAN AIRWAY EPITHELIAL CELLS TO OZONE AND PARTICULATE MATTER: EFFECTS ON ARACHIDONIC ACID METABOLISM  

EPA Science Inventory

Co-exposure of human airway epithelial cells to ozone and particulate matter: effects on arachidonic acid metabolism. D. Stamm1, L. Dailey2, M.C. Madden2 1 University of North Carolina-Chapel Hill, School of Medicine 2 U.S. EPA, ORD, NHEERL, HSD, Chapel Hill, NC, USA...

377

Evaluation of single cell sources of docosahexaenoic acid and arachidonic acid: A 4-week oral safety study in rats  

Microsoft Academic Search

Docosahexaenoic acid (DHA) and arachidonic acid (ARA) are secreted in human milk and consumed by the nursing neonate but are not present in infant formulas currently available in the US. Supplementation of formulas with DHA and ARA may be particularly important for premature infants, who have less accretion of these fatty acids in utero than term infants. Some experts suggest

G. J Wibert; R. A Burns; D. A Diersen-Schade; C. M Kelly

1997-01-01

378

Role of Cytochrome P-450 Enzymes and Metabolites of Arachidonic Acid in the Control of Vascular Tone  

Microsoft Academic Search

The metabolism of arachidonic acid (AA) into vasoactive products by cyclooxygenase and lipoxygenase enzymes has been well described, as has their biological relevance. Recently, a number of studies have demonstrated the ability of cytochrome P-450 (P450) enzymes to metabolize AA into biologically important regulators of vascular tone. There are two categories of vasoactive P450 metabolites, namely those catalyzed by epoxygenase

D. R. Harder; W. B. Campbell; R. J. Roman

1995-01-01

379

Magnetically driven middle ear ossicles for optical measurement of vibrations in an ear with opened tympanic membrane  

NASA Astrophysics Data System (ADS)

Vibrations of the middle ear ossicles are easily measured by means of laser vibrometry. However, laser vibrometry requires free visual access to the object under investigation, and acquiring free visual access to the ossicles through the ear canal requires the removal of the tympanic membrane (TM), with the result that the ossicles can no longer be stimulated acoustically. To overcome this, we devised a new setup in which the ossicles can be driven magnetically. After measuring the response of the TM to an acoustic signal, we then remove it and attach a small magnet to the exposed manubrium (a part of the most lateral auditory ossicle, the malleus, which is normally attached to the TM). An electromagnetic excitation coil is then used to drive the magnet, and the output to the coil adjusted until the vibration of the manubrium, as measured by the vibrometer, matches that measured in response to the acoustic signal. Such a setup may have uses in research on middle ear mechanics, such as the measurement of nonlinearities in their response, as well as applications in the diagnosis of middle ear conditions such as the fixation of the ossicles by otosclerosis or in chronic otitis media. We describe our setup and discuss the viability of our method and its future clinical potential by presenting some measurements on an artificially fixated ear.

Peacock, J.; von Unge, M.; Dirckx, J.

2013-12-01

380

Magnetically driven middle ear ossicles for optical measurement of vibrations in an ear with opened tympanic membrane.  

PubMed

Vibrations of the middle ear ossicles are easily measured by means of laser vibrometry. However, laser vibrometry requires free visual access to the object under investigation, and acquiring free visual access to the ossicles through the ear canal requires the removal of the tympanic membrane (TM), with the result that the ossicles can no longer be stimulated acoustically. To overcome this, we devised a new setup in which the ossicles can be driven magnetically. After measuring the response of the TM to an acoustic signal, we then remove it and attach a small magnet to the exposed manubrium (a part of the most lateral auditory ossicle, the malleus, which is normally attached to the TM). An electromagnetic excitation coil is then used to drive the magnet, and the output to the coil adjusted until the vibration of the manubrium, as measured by the vibrometer, matches that measured in response to the acoustic signal. Such a setup may have uses in research on middle ear mechanics, such as the measurement of nonlinearities in their response, as well as applications in the diagnosis of middle ear conditions such as the fixation of the ossicles by otosclerosis or in chronic otitis media. We describe our setup and discuss the viability of our method and its future clinical potential by presenting some measurements on an artificially fixated ear. PMID:24387412

Peacock, J; von Unge, M; Dirckx, J

2013-12-01

381

Eustachian tube function in patients with inner ear disorders.  

PubMed

The influence of Eustachian tube (ET) dysfunction on the inner ear fluid pressure and thus on the inner ear function in Meniere's disease has been discussed controversially. So far, most of the studies examining ET function in inner ear disorders indirectly analyzed ET function by tympanometric methods. The present study directly studied ET function in inner ear disorders by sonotubometry. Healthy subjects and patients with Meniere's disease, sudden sensorineural hearing loss, cholesteatoma and chronic suppurative otitis media were examined by sonotubometry. Mean increase of sound pressure intensity (dB) and mean duration of sound pressure increase (s) were analyzed. Highest mean increase of sound pressure intensity was seen in healthy subjects when using >5 dB peaks (11.6 ± 0.7 dB) and >0 dB peaks (9.6 ± 0.6 dB). Comparative analysis including bilateral ears showed decreased ET function in patients with cholesteatoma (p = 0.002) and in patients with Meniere's disease (p = 0.003) when using >0 dB peaks. Examination of each specific ET opening maneuver showed impaired ET function in pathological ears of patients with cholesteatoma and with Meniere's disease, during yawning (p = 0.001; p < 0.001), dry swallowing (p = 0.010; p = 0.049), Toynbee maneuver (p = 0.033; p = 0.032) and drinking (p = 0.044; p = 0.027). Mild ET dysfunction is detected in patients with Meniere's disease by direct sonotubometric assessment of ET function. PMID:22941437

Park, Jonas J-H; Luedeke, Inger; Luecke, Kerstin; Emmerling, Oliver; Westhofen, Martin

2013-05-01

382

Ion Channel Gene Expression in the Inner Ear  

PubMed Central

The ion channel genome is still being defined despite numerous publications on the subject. The ion channel transcriptome is even more difficult to assess. Using high-throughput computational tools, we surveyed all available inner ear cDNA libraries to identify genes coding for ion channels. We mapped over 100,000 expressed sequence tags (ESTs) derived from human cochlea, mouse organ of Corti, mouse and zebrafish inner ear, and rat vestibular end organs to Homo sapiens, Mus musculus, Danio rerio, and Rattus norvegicus genomes. A survey of EST data alone reveals that at least a third of the ion channel genome is expressed in the inner ear, with highest expression occurring in hair cell-enriched mouse organ of Corti and rat vestibule. Our data and comparisons with other experimental techniques that measure gene expression show that every method has its limitations and does not per se provide a complete coverage of the inner ear ion channelome. In addition, the data show that most genes produce alternative transcripts with the same spectrum across multiple organisms, no ion channel gene variants are unique to the inner ear, and many splice variants have yet to be annotated. Our high-throughput approach offers a qualitative computational and experimental analysis of ion channel genes in inner ear cDNA collections. A lack of data and incomplete gene annotations prevent both rigorous statistical analyses and comparisons of entire ion channelomes derived from different tissues and organisms. Electronic supplementary material The online version of this article (doi:10.1007/s10162-007-0082-y) contains supplementary material, which is available to authorized users.

Sokolowski, Bernd H.A.; Morton, Cynthia C.; Giersch, Anne B.S.

2007-01-01

383

Upregulation of Retinoic Acid-Inducible Gene-I in T24 Urinary Bladder Carcinoma Cells Stimulated with Interferon-?  

Microsoft Academic Search

IMAIZUMI, T., YAGIHASHI, N., HATAKEYAMA, M., YAMASHITA, K., ISHIKAWA, A., TAIMA, K., YOSHIDA, H., YAGIHASHI, S. and SATOH, K. Upregulation of Retinoic Acid- Inducible Gene-I in T24 Urinary Bladder Carcinoma Cells Stimulated with Interfer- on-? . Tohoku J. Exp. Med., 2004, 203 (4), 313-318 ?? Urinary bladder epithelial cells play an important role in the host defense against urinary tract

Tadaatsu Imaizumi; Norito Yagihashi; Masaharu Hatakeyama; Koji Yamashita; Akira Ishikawa; Kageaki Taima; Hidemi Yoshida; Soroku Yagihashi; Kei Satoh

2004-01-01

384

Protective Effects of Prenatal Administration of Folic Acid on Retinoic Acid-Induced Cellular Damages of Meckel's Cartilage in Rats  

Microsoft Academic Search

common congenital deformities. Meckel's cartilage plays a major role in the development of the mandible and is highly susceptible to maternal teratogenic drug use. We therefore investigated possible protective effects of prenatal administration of folic acid on a retino- ic-acid induced maxillofacial defect model. Sprague-Dawley pregnant female rats (n = 36) were used in this study. Retinoic acid was administered

Deniz Firat; Leyla Kuntsal; Yigit Sirin

2005-01-01

385

Bile acid-induced rat hepatocyte apoptosis is inhibited by antioxidants and blockers of the mitochondrial permeability transition  

Microsoft Academic Search

The accumulation of hydrophobic bile acids plays a role in the induction of apoptosis and necrosis of hepatocytes during cholestasis. The aim of this study was to determine in freshly isolated rat hepatocytes the roles of oxidant stress and the mitochondrial permeability transition (MPT) in bile acid-induced apoptosis. Hepatocytes isolated from adult male Sprague-Dawley rats were incubated for 4 hours

Baruch Yerushalmi; Rolf Dahl; Michael W. Devereaux; Eric Gumpricht; Ronald J. Sokol

2001-01-01

386

Inner ear supporting cells: Rethinking the silent majority  

PubMed Central

Sensory epithelia of the inner ear contain two major cell types: hair cells and supporting cells. It has been clear for a long time that hair cells play critical roles in mechanoreception and synaptic transmission. In contrast, until recently the more abundant supporting cells were viewed primarily as serving primarily structural and homeostatic functions. In this review we discuss the growing information about the roles that supporting cells play in the development, function and maintenance of the inner ear, their activities in pathological states, their potential for hair cell regeneration, and the mechanisms underlying these processes.

Wan, Guoqiang; Corfas, Gabriel; Stone, Jennifer S

2014-01-01

387

"Turkey Ear" as a Cutaneous Maniestation of Tuberculosis  

PubMed Central

Lupus vulgaris is the most common morphological variant of cutaneous tuberculosis. Classical lupus lesions are often seen in the head and neck region. Turkey ear is a clinically descriptive term, previously being used for the earlobe with reddish indurated plaque lesions, which recently can be a sign for lupus vulgaris. A 65-year-old man presented with lupus vulgaris of the earlobe. The diagnosis was confirmed by conventional laboratory investigations and the patient showed well response to antituberculous therapy. This is the second reported case of “turkey ear” as a manifestation of cutaneous tuberculosis.

Kucukunal, Asl?; Ekmekci, Tugba R; Sak?z, Damlanur

2012-01-01

388

"Turkey ear" as a cutaneous maniestation of tuberculosis.  

PubMed

Lupus vulgaris is the most common morphological variant of cutaneous tuberculosis. Classical lupus lesions are often seen in the head and neck region. Turkey ear is a clinically descriptive term, previously being used for the earlobe with reddish indurated plaque lesions, which recently can be a sign for lupus vulgaris. A 65-year-old man presented with lupus vulgaris of the earlobe. The diagnosis was confirmed by conventional laboratory investigations and the patient showed well response to antituberculous therapy. This is the second reported case of "turkey ear" as a manifestation of cutaneous tuberculosis. PMID:23248385

Küçükünal, Asl?; Ekmekçi, Tu?ba R; Sak?z, Damlanur

2012-11-01

389

Effect of selenium and vitamin E deficiencies on the fate of arachidonic acid in rat isolated lungs  

SciTech Connect

The fate of exogenous /sup 14/C-arachidonic acid (/sup 14/C-AA) was investigated in the isolated lungs of rats fed selenium and vitamin E deficient diet or diets supplemented with selenium and/or vitamin E. When 80 nmol of /sup 14/C-AA was infused into the pulmonary circulation most of the infused /sup 14/C-AA was found in different phospholipid and neutral lipid fractions of the perfused lungs. Only less than ten percent of the infused radioactivity was recovered in the perfusion effluent. The amount of arachidonate metabolites in the perfusion effluent was negligible, and most of the radioactivity in the perfusion effluent consisted of unmetabolized arachidonate. Selenium deficiency had no significant effect on the distribution of /sup 14/C-AA in different lung lipid fractions. However, in the lungs of vitamin E deficient rats the amount of radioactivity was slightly increased in the neutral lipid fraction, which was due to the increased amount of /sup 14/C-AA in the diacylglycerols. The amount of radioactivity was increased especially in the 1,3-diacylglycerols. The amount of radioactivity was increased especially in the 1,3-diacylglycerols. The amount of /sup 14/C-AA in the triacylglycerols and in different phospholipids was not significantly changed. The present study might indicate that selenium deficiency has no significant effect on the fate of exogenous arachidonic acid in isolated rat lungs, and that vitamin E deficiency would slightly increase the amount of arachidonic acid in the diacylglycerols.

Uotila, P.; Puustinen, T.

1985-06-01

390

Co-compartmentalization of MAP kinases and cytosolic phospholipase A2 at cytoplasmic arachidonate-rich lipid bodies.  

PubMed Central

Lipid bodies are inducible lipid domains abundantly present in leukocytes engaged in inflammation. They are rich in esterified arachidonate and are also potential sites for eicosanoid-forming enzyme localization. It is therefore of interest to know whether arachidonate-releasing cytosolic phospholipase A2 (cPLA2) localizes at lipid bodies. Here, we present evidence that cPLA2 and its activating protein kinases, mitogen-activated protein (MAP) kinases, co-localize at lipid bodies. U937 cells express high levels of cPLA2 and contain numerous cytoplasmic lipid bodies. Using double-labeling immunocytochemistry we demonstrated punctate cytoplasmic localizations of both cPLA2 and MAP kinases in U937 cells that were perfectly concordant with fluorescent fatty-acid-labeled lipid bodies. The co-localization of cPLA2 and MAP kinases at lipid bodies was confirmed by subcellular fractionation and immunoblot. Lipid body fractions free of cytosol and other organelles contained significant amounts of [14C]arachidonate-labeled phosphatidylcholine and cPLA2 enzymatic activities. Immunoblotting with specific antibodies identified cPLA2 as well as MAP kinases, including ERK1, ERK2, p85, and p38, in lipid bodies. The co-compartmentalization within arachidonate-rich lipid bodies of cPLA2 and its potentially activating protein kinases suggests that lipid bodies may be structurally distinct intracellular sites active in extracellular ligand-induced arachidonate release and eicosanoid formation. Images Figure 1 Figure 2 Figure 3 Figure 6 Figure 7

Yu, W.; Bozza, P. T.; Tzizik, D. M.; Gray, J. P.; Cassara, J.; Dvorak, A. M.; Weller, P. F.

1998-01-01

391

[Effect of quercetin on chemiluminescence of human platelets induced by arachidonic acid].  

PubMed

Arachidonic acid (AA)-induced platelet chemiluminescence (CL) was measured with a lumiphotometer. Quercetin remarkably inhibited the CL, the IC50 of quercetin was 3 mumol.L-1. When quercetin plus aspirin, which inhibits only cyclooxygenase, was added, the inhibitory rate of platelet-CL obviously increased (P < 0.01). On the other hand, the quercetin had a scavenging effect on superoxide anion radical using alkaline sodium dithionite solution generation. The IC50 was 20.9 mumol.L-1. In addition, superoxide dismutase of 0.1 mg.ml-1 inhibited the platelet-CL by 97.8%, while mannitol, a hydroxyl radical scavenger, only by 43.3% at a concentration of 80 mg.ml-1. These results suggest that the mechanism of the inhibiting AA-induced platelet-CL by quercetin was associated with scavenging the superoxide anion radical directly and with inhibiting the cyclooxygenase. PMID:8237407

Gu, Z L; Xie, M L; Qian, Z N

1993-05-01

392

Stimulated release of arachidonate and prostaglandins is vectorial in MDCK epithelial cells.  

PubMed

The receptor mediated activation of phospholipase A2 by appropriate ligands results in the synthesis and release of eicosanoids, a class of potent bioregulatory molecules. Madin-Darby canine kidney cells (MDCK) are polarized epithelial cells, with structurally and functionally distinct plasma membrane domains separated by tight junctions. Using MDCK cells grown in dual sided chambers, we show in this report, that a) the receptor mediated release of prostaglandins and arachidonate into the extracellular medium is predominantly unidirectional, b) the direction of release is agonist specific, and c) the magnitude of the response due to a given agonist is cell-domain specific. These characteristics, if operative in vivo, would contribute towards the optimal function of trans-cellular metabolism of eicosanoids already demonstrated. PMID:1438885

Cortizo, A M; Besterman, J M; Leitner, P P; Chandrabose, K A

1992-10-01

393

Inhibition of sheep platelet arachidonate metabolism by flavonoids from Spanish and Indian medicinal herbs.  

PubMed

The influence of 22 flavonoids was studied on the arachidonic acid metabolism in sonicated sheep platelets. Flavones and flavonols possessing catechol groups inhibited 12-lipoxygenase. Sideritoflavone and quercetagetin-7-O-beta-D-glucoside were more selective than quercetin. Cirsiliol, hypolaetin, hypolaetin-8-O-beta-D-glucoside, gossypetin, gossypin, hibifolin and leucocyanidol were also 12-lipoxygenase inhibitors with some differences in potency and selectivity. Xanthomicrol was a weak cyclooxygenase inhibitor. These results suggest that lipoxygenase inhibition can play a role in the anti-inflammatory activity of hypolaetin-8-O-beta-D-glucoside, sideritoflavone, gossypin and hibifolin. On the other hand, the presence of sideritoflavone, hypolaetin-8-O-beta-D-glucoside, cirsiliol and xanthomicrol in several species of Sideritis may provide a basis for the use of such plants as anti-inflammatory agents. PMID:2116628

Ferrándiz, M L; Nair, A G; Alcaraz, M J

1990-03-01

394

Neutrophil chemotaxis and arachidonic acid metabolism are not linked: evidence from metal ion probe studies  

SciTech Connect

Heavy metal ions can inhibit arachidonic acid (AA) metabolism protect against ionophore cytotoxicity (ibid) and inhibit neutrophil chemotaxis. In this study they used Au/sup 3 +/, Zn/sup 2 +/, Cr/sup 3 +/, Mn/sup 2 +/ and Cu/sup 2 +/ as probes of the interrelationships among AA metabolism, ionophore-mediated cytotoxicity, and chemotaxis. Phospholipid deacylation was measured in ionophore-treated cells prelabeled with /sup 3/H-AA. Eicosanoid release from ionophore-treated cells was monitored by radioimmunoassay. Cytoprotection was quantitated as ability to exclude trypan blue. Chemotaxis toward f-met-leu-phe was measured by leading front analysis. The results imply that metal ions attenuate ionophore cytotoxicity by blocking phospholipid deacylation and eicosanoid release. In contrast to previous reports, no correlation between AA metabolism and chemotaxis was demonstrated, suggesting that these 2 processes are not linked.

Turner, S.R.; Turner, R.A.; Smith, D.M.; Johnson, J.A.

1986-03-05

395

A study of ozone-induced edema in the isolated rat lung in relation to arachidonic acid metabolism, mixed-function oxidases and angiotensin converting enzyme activities.  

PubMed

In order to elucidate the role of arachidonic acid in the pathogenesis of ozone-induced pulmonary edema, isolated rat lungs were exposed to 14C-arachidonic acid in the presence or absence of ozone and the incorporation of radiolabelled arachidonate into pulmonary cell lipids was studied. The perfusates from these studies were also subjected to differential extraction and thin layer chromatography (t.l.c.) to determine synthesis of both cyclo-oxygenase and lipoxygenase products. In the presence of an edemagenic concentration of ozone, isolated lungs incorporated significantly less exogenous arachidonic acid into phosphatidyl choline and phosphatidyl ethanolamine, whereas incorporation into phosphatidyl inositol or serine was not affected. The edemagenic concentration of ozone also increased production of a variety of arachidonic acid metabolites via cyclo-oxygenase and lipoxygenase pathways. In separate studies, a similar ozone exposure did not affect 14CO2 production, resulting from the metabolism of 14C-antipyrine by mixed function oxidases (MFO). Similarly, an edemagenic concentration of ozone did not affect pulmonary angiotensin converting enzyme activity (ACE) as determined by the rate of formation of 14C-hippuric acid from 14C-hippuryl-histidyl-leucine (14C-HHL). Thus, acute ozone exposure is specifically associated with a reduced incorporation of arachidonate into phospholipids and with an increased conversion of arachidonate into bio-active metabolites. PMID:1966904

Dutta, S; Chatterjee, M; Teknos, T N; Carlson, R W

1990-01-01

396

Arachidonic acid metabolites do not mediate toluene diisocyanate-induced airway hyperresponsiveness in guinea pigs  

SciTech Connect

Arachidonic acid metabolites have previously been demonstrated to mediate the airway hyperresponsiveness observed in guinea pigs and dogs after exposure to ozone. Guinea pigs were treated with indomethacin (a cyclooxygenase inhibitor), U-60,257 (piriprost, a 5-lipoxygenase inhibitor), or BW775c (a lipoxygenase and cyclooxygenase inhibitor) and exposed to air or 3 ppm TDI. Airway responsiveness to acetylcholine aerosol was examined 2 h after exposure. In control animals, the provocative concentration of acetylcholine which caused a 200% increase in pulmonary resistance over baseline (PC200) was significantly less (p less than 0.05) after exposure to TDI (8.6 +/- 2.0 mg/ml, geometric mean + geometric SE, n = 10) than after exposure to air (23.9 + 2.5 mg/ml, n = 14). The airway responsiveness to acetylcholine in animals treated with indomethacin or piriprost and exposed to TDI was not different from that of control animals exposed to TDI. Treatment with BW755c enhanced the airway hyperresponsiveness observed in animals exposed to TDI without altering the PC200 of animals exposed to air. The PC200 of animals treated with BW755c and exposed to TDI (2.3 + 0.8 mg/ml, n = 8) was significantly lower than the PC200 of control animals exposed to TDI (p less than 0.025). These results suggest that products of arachidonic acid metabolism are not responsible for TDI-induced airway hyperresponsiveness in guinea pigs. BW755c, however, appears to potentiate the TDI-induced airway hyperresponsiveness to acetylcholine by an as yet unidentified mechanism.

Gordon, T.; Thompson, J.E.; Sheppard, D.

1988-05-01

397

The Synthesis and In Vivo Pharmacokinetics of Fluorinated Arachidonic Acid: Implications for Imaging Neuroinflammation  

PubMed Central

Arachidonic acid (AA) is found in high concentrations in brain phospholipids and is released as a second messenger during neurotransmission and much more so during neuroinflammation and excitotoxicity. Upregulated brain AA metabolism associated with neuroinflammation has been imaged in rodents using [1-14C]AA and with PET in Alzheimer disease patients using [1-11C]AA. Radiotracer brain AA uptake is independent of cerebral blood flow, making it an ideal tracer despite altered brain functional activity. However, the 20.4-min radioactive half-life of 11C-AA and challenges of routinely synthesizing 11C fatty acids limit their translational utility as PET biomarkers. Methods As a first step to develop a clinically useful 18F-fluoroarachidonic acid (18F-FAA) with a long radioactive half-life of 109.8 min, we report here a high-yield stereoselective synthetic method of non-radioactive 20-19F-FAA. We tested its in vivo pharmacokinetics by infusing purified nonradioactive 19F-FAA intravenously for 5 min at 2 doses in unanesthetized mice and measured its plasma and brain distribution using gas chromatography–mass spectrometry. Results Incorporation coefficients of injected 19F-FAA into brain phospholipids (ratio of brain 19F-FAA concentration to plasma input function) were 3- to 29-fold higher for choline glycerophospholipid and phosphatidylinositol than for ethanolamine glycerophospholipid and phosphatidylserine at each of the 2 tested doses. The selectivities and values of incorporation coefficients were comparable to those reported after [1-14C]AA (the natural arachidonate) infusion in mice. Conclusion These results suggest that it would be worthwhile to translate our stereoselective synthetic method for 19F-FAA to synthesize positron-emitting 18F-FAA for human brain AA metabolism in neuroinflammatory disorders such as Alzheimer disease.

Pichika, Rama; Taha, Ameer Y.; Gao, Fei; Kotta, Kishore; Cheon, Yewon; Chang, Lisa; Kiesewetter, Dale; Rapoport, Stanley I.; Eckelman, William C.

2012-01-01

398

Glutamate signalling and secretory phospholipase A2 modulate the release of arachidonic acid from neuronal membranes.  

PubMed

The lipid mediators generated by phospholipases A(2) (PLA(2)), free arachidonic acid (AA), eicosanoids, and platelet-activating factor, modulate neuronal activity; when overproduced, some of them become potent neurotoxins. We have shown, using primary cortical neuron cultures, that glutamate and secretory PLA(2) (sPLA(2)) from bee venom (bv sPLA(2)) and Taipan snake venom (OS2) elicit synergy in inducing neuronal cell death. Low concentrations of sPLA(2) are selective ligands of cell-surface sPLA(2) receptors. We investigated which neuronal arachidonoyl phospholipids are targeted by glutamate-activated cytosolic calcium-dependent PLA(2) (cPLA(2)) and by sPLA(2). Treatment of (3)H-AA-labeled cortical neurons with mildly toxic concentrations of sPLA(2) (25 ng/ml, 1.78 nM) for 45 min resulted in a two- to threefold higher loss of (3)H-AA from phosphatidylcholine (PC) than from phosphatidylethanolamine (PE) and in minor changes in other phospholipids. A similar profile, although of greater magnitude, was observed 20 hr posttreatment. Glutamate (80 microM) induced much less mobilization of (3)H-AA than did sPLA(2) and resulted in a threefold greater degradation of (3)H-AA PE than of (3)H-AA PC by 20 hr posttreatment. Combining sPLA(2) and glutamate resulted in a greater degradation of PC and PE, and the N-methyl-D-aspartate receptor antagonist MK-801 only blocked glutamate effects. Thus, activation of the arachidonate cascade induced by glutamate and sPLA(2) under experimental conditions that lead to neuronal cell death involves the hydrolysis of different (perhaps partially overlapping) cellular phospholipid pools. PMID:12111845

Rodriguez De Turco, Elena B; Jackson, Fannie R; DeCoster, Mark A; Kolko, Miriam; Bazan, Nicolas G

2002-06-01

399

21 CFR 874.5300 - Ear, nose, and throat examination and treatment unit.  

Code of Federal Regulations, 2010 CFR

...CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Therapeutic Devices § 874.5300 Ear, nose, and throat examination...blowing apparatus, and receptacles for connection of specialized lights and examining instruments. (b) Classification....

2010-04-01

400

21 CFR 874.5300 - Ear, nose, and throat examination and treatment unit.  

Code of Federal Regulations, 2010 CFR

...CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Therapeutic Devices § 874.5300 Ear, nose, and throat examination...blowing apparatus, and receptacles for connection of specialized lights and examining instruments. (b) Classification....

2009-04-01

401

78 FR 55664 - Revisions to the Export Administration Regulations (EAR): Unverified List (UVL)  

Federal Register 2010, 2011, 2012, 2013

...120524116-2116-01] RIN 0694-AF70 Revisions to the Export Administration Regulations (EAR): Unverified...Security (BIS) proposes to amend the Export Administration Regulations (EAR) by: requiring exporters to file an Automated Export System (AES) record for all...

2013-09-11

402

77 FR 22191 - Revisions to the Export Administration Regulations (EAR): Export Control Classification Number...  

Federal Register 2010, 2011, 2012, 2013

...110310188-2058-03] RIN 0694-AF17 Revisions to the Export Administration Regulations (EAR): Export Control Classification Number 0Y521 Series...publishes this final rule, which amends the Export Administration Regulations (EAR) by...

2012-04-13

403

Tissue reaction to middle ear prostheses: in vivo observation (rabbit ear lobe) of polyethylene tube, stainless steel wire and absorbable gelatin sponge used in middle ear surgery.  

PubMed

Over the past ten years, polyethylene tube, stainless steel wire and absorbable gelatin sponge have come to be used in middle ear surgery. A modified Williams' steel chamber with a transparent central area was embedded in a rabbit ear lobe surgically, and cross-sectioned polyethylene tube, stainless steel wire or absorbable gelatin sponge were inserted respectively. The in vivo tissue reaction to each of these installed materials was observed daily microscopically. Finally, in the case of both the cross-sectioned polyethylene tube and the stainless steel wire, the chambers were fixed with 10% formalin solution and the contents stained for histological study. The results were as follows: Absorbable gelatin sponge was absorbed completely by phagocytosis in 62 days. Polyethylene tube was encapsulated by a layer of fibroblasts by day 110 in one case and by day 140 in another case; these findings were confirmed histologically on day 110 and 281. Almost all the surface of the stainless steel wire was encapsulated by a layer consisting of giant cells, on which a dense fibrous layer was superimposed by day 82. It is concluded that polyethylene tube, stainless steel wire, and absorbable gelatin sponge should be well tolerated in middle ear surgery. PMID:137659

Ohsaki, K; Saito, R

1976-10-01

404

[Hereditary combination of branchial fistulas and middle ear malformations (author's transl)].  

PubMed

Four cases with hereditary combinations of branchial fistulas and middle ear malformations in three generations of one family are reported. We found preauricular fistulas and lateral cervical fistulas combined with different types of middle ear dysplasias. In one case a preauricular fistula running through the middle ear and ending in the dura could be exstirpated. Such rare varieties must be considered, when preauricular fistulas are found together with congenital middle ear deafness. PMID:763058

Pau, H W; Koch, U

1979-01-01

405

Measurements of human middle ear forward and reverse acoustics: Implications for otoacoustic emissions  

Microsoft Academic Search

Middle and inner ears from human cadaver temporal bones were stimulated in the forward direction by an ear-canal sound source, and in the reverse direction by an inner-ear sound source. For each stimulus type, three variables were measured: (a) Pec-ear-canal pressure with a probe-tube microphone within 3 mm of the eardrum, (b) Vst-stapes velocity with a laser interferometer, and (c)

Sunil Puria

2003-01-01

406

Detecting Walking Gait Impairment with an Ear-worn Sensor  

Microsoft Academic Search

This paper investigates an ear worn sensor for the development of a gait analysis framework. Instead of explicitly defining gait features that indicate injury or impairment, an automatic method of feature extraction and selection is proposed. The proposed framework uses multi-resolution wavelet analysis and margin based feature selection. It was validated on three datasets; the first simulating a leg injury,

Louis Atallah; Omer Aziz; Benny P. L. Lo; Guang-zhong Yang

2009-01-01

407

Meis gene expression patterns in the developing chicken inner ear.  

PubMed

We are interested in stable gene network activities operating sequentially during inner ear specification. The implementation of this patterning process is a key event in the generation of functional subdivisions of the otic vesicle during early embryonic development. The vertebrate inner ear is a complex sensory structure that is a good model system for characterization of developmental mechanisms controlling patterning and specification. Meis genes, belonging to the TALE family, encode homodomain-containing transcription factors remarkably conserved during evolution, which play a role in normal and neoplastic development. To gain understanding of the possible role of homeobox Meis genes in the developing chick inner ear, we comprehensively analyzed their spatiotemporal expression patterns from early otic specification stages onwards. In the invaginating otic placode, Meis1/2 transcripts were observed in the borders of the otic cup, being absent in the portion of otic epithelium closest to the hindbrain. As development proceeds, Meis1 and Meis2 expressions became restricted to the dorsomedial otic epithelium. Both genes were strongly expressed in the entire presumptive domain of the semicircular canals, and more weakly in all associated cristae. The endolymphatic apparatus was labeled in part by Meis1/2. Meis1 was also expressed in the lateral wall of the growing cochlear duct, while Meis2 expression was detected in a few cells of the developing acoustic-vestibular ganglion. Our results suggest a possible role of Meis assigning regional identity in the morphogenesis, patterning, and specification of the developing inner ear. PMID:21120931

Sánchez-Guardado, Luis Óscar; Ferran, José Luis; Rodríguez-Gallardo, Lucía; Puelles, Luis; Hidalgo-Sánchez, Matías

2011-01-01

408

Efficiency of ear protectors in laboratory and real life tests.  

PubMed

The effectiveness of ten different ear-protectors (6 types of earmuffs and 4 types of earplugs) has been tested under laboratory conditions and in the real occupational environment. Three methods were used: (1) physical, utilizing a dummy head; (2) subjective, real-ear, executed on trained human subjects; (3) subjective, measuring TTS2 resulting from occupational, one-workday exposure. It could be shown that the ear protection efficiency ascertained on the basis of TTS2 measurements on workers exposed to noise in their occupational environment is, in nearly all cases, smaller than the efficiency expected, taking into account the sound damping of the same protectors, tested under laboratory conditions, using the physical or real-ear method. Measurements of TTS2 were found to give the best data needed to define the protectors' efficiency, since they include, simultaneously, the impact of various environmental factors, the subjective reactiveness, the nature of the professional task and the acoustical features of the protector used. Therefore this method enables the estimation of the real protection given to workers with a risk of noise-induced hearing loss. PMID:2379964

Pawlas, K; Grzesik, J

1990-01-01

409

Baby corn, green ear, and grain yield of corn cultivars  

Microsoft Academic Search

Most maize cultivars have been developed for grain production. Because superior cultivars may differ in their exploiting purposes, interest has been demonstrated for the evaluation of corn cultivars with regard to their baby corn, green ear, and grain yields production ability. In the present work ten corn cultivars (AG 405, AG 1051, AG 2060, AG 6690, AG 7575, AG 8080,

Itala Paula de C. Almeida; Paulo Sérgio L. e Silva; Maria Z. de Negreiros; Zenaide Barbosa

2005-01-01

410

An outbreak of erysipelas in eared grebes (Podiceps nigricollis)  

USGS Publications Warehouse

An outbreak of erysipelas killed an estimated 5,000 aquatic birds on Great Salt Lake (Utah) in late November, 1975. Although several thousand ducks and gulls were using the lake, at least 99 percent of the victims were eared grebes. A hypothetical explanation for the selective mortality is offered.

Jensen, W. I.; Cotter, S. E.

1976-01-01

411

The major histocompatibility complex of tassel-eared squirrels  

Microsoft Academic Search

The complexity and polymorphism of sequences related to the class I and class II genes of mammalian major histocompatibility complexes (MHCs) were investigated in the tassel-eared squirrel subspecies Sciurus aberti kaibabensis or Kaibab squirrel. Kaibab squirrels are geographically isolated on the Kaibab plateau north of the Grand Canyon in Arizona. Genomic DNA from 22 individuals was digested with Eco RI

Peter J. Wettstein; Jack S. States

1986-01-01

412

The major histocompatibility complex of tassel-eared squirrels  

Microsoft Academic Search

The extent of polymorphism and the rate of divergence of class I and class II sequences mapping to the mammalian major histocompatibility complex (MHC) have been the subject of experimentation and speculation. To provide further insight into the evolution of the MHC we have initiated the analysis of two geographically isolated subspecies of tassel-eared squirrels. In the preceding communication we

Peter J. Wettstein; Jack S. States

1986-01-01

413

Protecting short-term intravascular ear catheters in healthy rabbits.  

PubMed

Researchers may place a catheter in the ear vessel of a rabbit for a short period of time in order to collect repeated blood samples without extensive restraint of the animal. Maintaining such a catheter in a healthy rabbit can be challenging, as the animal may scratch at the ear, removing the catheter or forming a large hematoma that might impede blood sampling. The authors developed a technique for protecting the indwelling catheter by cutting a section of moleskin to the same shape as the ear and gluing it to the surface of the ear and the catheter. They applied this technique to collect multiple blood samples during 12-h periods from nine rabbits in a pharmacokinetics study. Catheters remained patent in five rabbits for 12 h, in two rabbits for 8 h, in one rabbit for 6 h and in one rabbit for 4 h. This technique allowed for collection of repeated blood samples and prevented the rabbits from interfering with the catheter while allowing them to move freely during the sampling period. PMID:22261889

Sampieri, Francesca; Orchard, Rekha N; Antonopoulos, Aphroditi J; Hamilton, Donald L

2012-02-01

414

High throughput gene expression analysis of the inner ear.  

PubMed

The mouse auditory and vestibular epithelia consist of a complex array of many different cell types. Over the last decade microarrays were used to characterize gene expression in the inner ear. Studies were performed on wild type mice to identify deafness genes, transcriptional networks activated during development, or identify miRNA with a functional role in the ear. Other studies focused on the molecular response of the inner ear to stimuli ranging from ototoxic medications to hypergravity and caloric restriction. Finally, microarrays were used to identify transcriptional networks activated downstream of deafness genes. As template-free high throughput gene expression profiling methods such as RNA-seq are increasingly popular, we offer a critical review of the data generated over the last decade relating to microarrays for gene expression profiling of the inner ear. Moreover, as most of the published data is available through the gene expression omnibus (GEO), we demonstrate the feasibility of integrating data from independent experiments to reach novel insights. PMID:22710153

Hertzano, Ronna; Elkon, Ran

2012-06-01

415

Histamine receptors in the vasculature of the rabbit ear  

Microsoft Academic Search

Summary Histamine has a dual action on the isolated perfused ear preparation of the rabbit. The amine induced a dose-dependent rise in perfusion pressure when the preparation was perfused with Krebs' solution. This pressor response was reversed to a depressor effect when mepyramine was added to the perfusion fluid. This depressor effect of the amine was also dose-related. Metiamide competitively

Z. Sevim Ercan; R. Kazim Tiirker

1975-01-01

416

832. Efficient Readministration of Adenovectors to the Inner Ear  

Microsoft Academic Search

Adenovectors have been extensively studied and provide one of the most flexible vehicles for gene delivery to a wide variety of cells. A number of studies have demonstrated the ability of Ad5 adenovectors to deliver genes to the inner ear without any associated loss of auditory function. We have previously shown that delivery of the atonal gene with an adenovirus

Hinrich Staecker; Mark Praetorius; Chi Hsu; Douglas E. Brough

2006-01-01

417

Research Project on Ear Infections Dramatizes Challenge of Conflicts.  

ERIC Educational Resources Information Center

An unusual conflict-of-interest case involving the federal government, a university researcher on ear infections, and the pharmaceutical industry has renewed the debate over what constitutes unacceptable conflict of interest, federal review of medical treatment, government protection against research bias, and disclosure of research project…

Cordes, Colleen

1993-01-01

418

Future Approaches for Inner Ear Protection and Repair  

ERIC Educational Resources Information Center

Health care professionals tending to patients with inner ear disease face inquiries about therapy options, including treatments that are being developed for future use but not yet available. The devastating outcome of sensorineural hearing loss, combined with the permanent nature of the symptoms, make these inquiries demanding and frequent. The…

Shibata, Seiji B.; Raphael, Yehoash

2010-01-01

419

Acoustic Reflectometry versus Tympanometry in Pediatric Middle Ear Screenings.  

ERIC Educational Resources Information Center

Use of acoustic reflectometry was compared with tympanometry in middle ear screenings for 357 children, aged 5 months to 19 years. Results were analyzed according to sex, age, and sensorineural hearing status. Intratest reliability was highly significant and positive predictive accuracy and specificity rates were excellent, but sensitivity rates…

Holmes, Alice E.; And Others

1989-01-01

420

Automatic 3D Ear Reconstruction Based on Binocular Stereo Vision  

Microsoft Academic Search

This paper presents an automatic 3D ear reconstruction method based on binocular stereo vision. At first, we calibrate the stereo vision system by Zhang's method. Then the quasi-dense matching method is performed. We use SIFT feature based matching approach and the coarse to fine strategy to compute the seed matches. The adapted match propagation algorithm with known epipolar geometry constraint

Hui Zeng; Zhi-chun Mu; Kai Wang; Chao Sun

2009-01-01

421

Redundant functions of Rac GTPases in inner ear morphogenesis  

PubMed Central

Development of the mammalian inner ear requires coordination of cell proliferation, cell fate determination and morphogenetic movements. While significant progress has been made in identifying developmental signals required for inner ear formation, less is known about how distinct signals are coordinated by their downstream mediators. Members of the Rac family of small GTPases are known regulators of cytoskeletal remodeling and numerous other cellular processes. However, the function of Rac GTPases in otic development is largely unexplored. Here, we show that Rac1 and Rac3 redundantly regulate many aspects of inner ear morphogenesis. While no morphological defects were observed in Rac3-/- mice, Rac1CKO; Rac3-/- double mutants displayed enhanced vestibular and cochlear malformations compared to Rac1CKO single mutants. Moreover, in Rac1CKO; Rac3-/- mutants, we observed compromised E-cadherin-mediated cell adhesion, reduced cell proliferation and increased cell death in the early developing otocyst, leading to a decreased size and malformation of the membranous labyrinth. Finally, cochlear extension was severely disrupted in Rac1CKO; Rac3-/-mutants, accompanied by a loss of epithelial cohesion and formation of ectopic sensory patches underneath the cochlear duct. The compartmentalized expression of otic patterning genes within the Rac1CKO; Rac3-/- mutant otocyst was largely normal, however, indicating that Rac proteins regulate inner ear morphogenesis without affecting cell fate specification. Taken together, our results reveal an essential role for Rac GTPases in coordinating cell adhesion, cell proliferation, cell death and cell movements during otic development.

Grimsley-Myers, Cynthia M.; Sipe, Conor W.; Wu, Doris K.; Lu, Xiaowei

2012-01-01

422

MicroRNAs in sensorineural diseases of the ear  

PubMed Central

Non-coding microRNAs (miRNAs) have a fundamental role in gene regulation and expression in almost every multicellular organism. Only discovered in the last decade, miRNAs are already known to play a leading role in many aspects of disease. In the vertebrate inner ear, miRNAs are essential for controlling development and survival of hair cells. Moreover, dysregulation of miRNAs has been implicated in sensorineural hearing impairment, as well as in other ear diseases such as cholesteatomas, vestibular schwannomas, and otitis media. Due to the inaccessibility of the ear in humans, animal models have provided the optimal tools to study miRNA expression and function, in particular mice and zebrafish. A major focus of current research has been to discover the targets of the miRNAs expressed in the inner ear, in order to determine the regulatory pathways of the auditory and vestibular systems. The potential for miRNAs manipulation in development of therapeutic tools for hearing impairment is as yet unexplored, paving the way for future work in the field.

Ushakov, Kathy; Rudnicki, Anya; Avraham, Karen B.

2013-01-01

423

Carcinoma of the middle ear and external auditory canal  

Microsoft Academic Search

Thirty-one patients with malignant tumors of the middle ear and external auditory canal (EAC) were observed at the University of Virginia Hospital from 1956 through 1980. Of 27 patients with carcinoma, 21 had squamous cell carcinoma, 4 had basal cell carcinoma and 2 had adenoid cystic carcinoma. The 27 patients with carcinoma are reviewed with regard to clinical presentation, treatment

S. S. Hahn; J. A. Kim; N. Goodchild; W. C. Constable

1983-01-01

424

A randomised controlled trial of surgery for glue ear  

Microsoft Academic Search

OBJECTIVE--To assess the effect of five different surgical treatments for glue ear (secretory otitis media) on improvement in hearing and, assuming one or more treatments to be effective, to identify the appropriate indications for surgery. DESIGN--Randomised controlled trial of children receiving (a) adenoidectomy, bilateral myringotomy, and insertion of a unilateral grommet; (b) adenoidectomy, unilateral myringotomy, and insertion of a unilateral

N A Black; C F Sanderson; A P Freeland; M P Vessey

1990-01-01

425

Early Middle Ear Effusion and Language at Age Seven  

ERIC Educational Resources Information Center

This study examined the relation of middle ear effusion (MEE) in the first 3 years of life to language outcomes at age seven. It was hypothesized, on the basis of a literature review, that (1) a low, but positive relation between early MEE and language measures in general will be observed at age seven, and (2) major effects will be demonstrated…

Johnson, Dale L.; McCormick, David P.; Baldwin, Constance D.

2008-01-01

426

Ear differences in the recall of fricatives and vowels  

Microsoft Academic Search

Two experiments on the free recall of dichotically presented synthetic speech sounds are reported. The first shows that the right ear advantage for initial fricative consonants is not simply a function of the recognition response class, but that it is also a function of the particular acoustic cues used to achieve that response. This is true both for the whole

C. J. Darwin

1971-01-01

427

Refractory erythromelalgia of the ears: response to mexiletine.  

PubMed

Erythromelalgia is a rare condition characterized by burning pain, erythema, swelling, and increased temperature usually in the extremities. We present an unusual presentation of erythromelalgia of the ears in a patient who has been refractory to multiple therapies and in whom relief of symptoms was achieved with the use of mexiletine. A review of clinical presentation, pathophysiology, and therapeutic options are presented. PMID:20392536

Vivas, Alejandra C; Escandon, Julia; Kirsner, Robert S

2011-01-01

428

Acid-induced changes in DOC quality in an experimental whole-lake manipulation  

SciTech Connect

Fluorescence analyses of archived water samples were used to typify dissolved organic carbon (DOC) quality in experimentally acidified lakes and reference lakes at the Experimental Lakes Area, in northwestern Ontario. Carbon-specific DOC fluorescence (CSF) during peak acidification was 40--50% of that for a high-DOC reference lake and similar to a low-DOC reference lake. Reference lakes showed similar but smaller decreases in CSF during several years of prolonged drought in the late 1980s. During the 1990s, recovery from acidification resulted in increased CSF, whereas reference lakes remained unchanged during the same time period. In addition to causing decreased [DOC], acidification causes changes in fluorescence-peak geometry that indicate a switch in DOC quality from allochthonous to autochthonous-like during acidification. The acid-induced change in DOC quality was likely due to increased chemical oxidation or precipitation of the UV-absorbent aromatic portions of allochthonous DOC molecules, leaving more UV-transparent aliphatic chains. The change in the nature of DOC following acidification and drought may have an important role in physical, biological, and chemical processes within these lakes. With recovery from acidification, DOC quality has also recovered.

Donahue, W.F.; Schindler, D.W. [Univ. of Alberta, Edmonton (Canada). Dept. of Biological Sciences] [Univ. of Alberta, Edmonton (Canada). Dept. of Biological Sciences; Page, S.J.; Stainton, M.P. [Freshwater Inst., Winnipeg, Manitoba (Canada)] [Freshwater Inst., Winnipeg, Manitoba (Canada)

1998-10-01

429

Unsaturated fatty acids induce calcium influx into keratinocytes and cause abnormal differentiation of epidermis.  

PubMed

Abnormal follicular keratinization is involved in comedogenesis in acne vulgaris. We recently demonstrated that calcium influx into epidermal keratinocytes is associated with impaired skin barrier function and epidermal proliferation. Based on these results, we hypothesized that sebum components affect calcium dynamics in the keratinocyte and consequently induce abnormal keratinization. To test this idea, we first observed the effects of topical application of sebum components, triglycerides (triolein), saturated fatty acids (palmitic acid and stearic acid), and unsaturated fatty acids (oleic acid and palmitoleic acid) on hairless mouse skin. Neither triglyceride nor saturated fatty acids affected the skin surface morphology or epidermal proliferation. On the other hand, application of unsaturated fatty acids, oleic acid, and palmitoleic acid induced scaly skin, abnormal keratinization, and epidermal hyperplasia. Application of triglycerides and saturated fatty acids on cultured human keratinocytes did not affect the intracellular calcium concentration ([Ca(2+)](i)), whereas unsaturated fatty acids increased the [Ca(2+)](i) of the keratinocytes. Moreover, application of oleic acid on hairless mouse skin induced an abnormal calcium distribution in the epidermis. These results suggest that unsaturated fatty acids in sebum alter the calcium dynamics in epidermal keratinocytes and induce abnormal follicular keratinization. PMID:15854043

Katsuta, Yuji; Iida, Toshii; Inomata, Shinji; Denda, Mitsuhiro

2005-05-01

430

Platelet-activating factor mediates acid-induced lung injury in genetically engineered mice  

PubMed Central

Adult respiratory distress syndrome (ARDS) is an acute lung injury of high mortality rate, and the molecular mechanisms underlying it are poorly understood. Acid aspiration–induced lung injury is one of the most common causes of ARDS, characterized by an increase in lung permeability, enhanced polymorphonuclear neutrophil (PMN) sequestration, and respiratory failure. Here, we investigated the role of platelet-activating factor (PAF) and the PAF receptor (PAFR) gene in a murine model of acid aspiration–induced lung injury. Overexpression of the PAFR gene in transgenic mice enhanced lung injury, pulmonary edema, and deterioration of gas exchange caused by HCl aspiration. Conversely, mice carrying a targeted disruption of the PAFR gene experienced significantly less acid-induced injury, edema, and respiratory failure. Nevertheless, the efficiency of PMN sequestration in response to acid aspiration was unaffected by differences in PAFR expression level. The current observations suggest that PAF is involved in the pathogenesis of acute lung injury caused by acid aspiration. Thus, inhibition of this pathway might provide a novel therapeutic approach to acute lung injury, for which no specific pharmaceutical agents are currently available.

Nagase, Takahide; Ishii, Satoshi; Kume, Kazuhiko; Uozumi, Naonori; Izumi, Takashi; Ouchi, Yasuyoshi; Shimizu, Takao

1999-01-01

431

Butyric acid induces apoptosis via oxidative stress in Jurkat T-cells.  

PubMed

Reactive oxygen species (ROS) are essential for the induction of T-cell apoptosis by butyric acid, an extracellular metabolite of periodontopathic bacteria. To determine the involvement of oxidative stress in apoptosis pathways, we investigated the contribution of ROS in mitochondrial signaling pathways, death-receptor-initiated signaling pathway, and endoplasmic reticulum stress in butyric-acid-induced T-cell apoptosis. N-acetyl-L-Cysteine (NAC) abrogated mitochondrial injury, cytochrome c, AIF, and Smac release, and Bcl-2 and Bcl-xL suppression and Bax and Bad activation induced by butyric acid. However, the decrease in cFLIP expression by butyric acid was not restored by treatment with NAC; increases in caspase-4 and -10 activities by butyric acid were completely abrogated by NAC. NAC also affected the elevation of GRP78 and CHOP/GADD153 expression by butyric acid. These results suggest that butyric acid is involved in mitochondrial-dysfunction- and endoplasmic reticulum stress-mediated apoptosis in human Jurkat T-cells via a ROS-dependent mechanism. PMID:20439934

Kurita-Ochiai, T; Ochiai, K

2010-07-01

432

Protocatechuic acid induces angiogenesis through PI3K-Akt-eNOS-VEGF signalling pathway.  

PubMed

In this study, we sought to elucidate whether protocatechuic acid contributes to induce angiogenesis as well as its mechanisms. To this end, we examined the role of protocatechuic acid on human brain microvascular endothelial cell line (HBMEC) proliferation, invasion and tube formation in in vitro. For the study of mechanisms involved, the phosphoinositide 3 kinase (PI3K)-Akt inhibitor LY294002, the endothelial nitric oxide synthase (eNOS) inhibitor L-NAME, vascular endothelial growth factor (VEGF), antagonist sFlt-1 and VEGF receptor blocker SU-1498 were used. Proliferation of HBMEC was tested by MTT. Scratch adhesion test was used to assess the ability of invasion. A Matrigel tube formation assay was performed to test capillary tube formation ability. PI3K-Akt-eNOS-VEGF pathway activation in HBMEC was tested by Western blot. Our data suggested that protocatechuic acid induces angiogenesis in vitro by increasing proliferation, invasion and tube formation. VEGF expression was increasing by protocatechuic acid and counteracted by VEGF antagonist sFlt-1, LY294002 and L-NAME in HBMEC. Tube formation was increased by protocatechuic acid and counteracted by VEGF receptor blocker-SU1498, LY294002 and L-NAME. These data suggest that protocatechuic acid may be a candidate therapy for stroke recovery by promoting angiogenesis via a programmed PI3K/Akt/eNOS/VEGF signalling axis. PMID:23738793

Kang, Zechun; Zhu, Haibo; Jiang, Wanglin; Zhang, Shuping

2013-10-01

433

Pulmonary vasoconstriction in oleic acid induced lung injury. A morphometric study.  

PubMed Central

Distribution and severity of active vasoconstriction of muscular pulmonary arteries were morphometrically assessed in anaesthetized, paralysed and mechanically ventilated pigs with respiratory distress, induced by oleic acid. Vasoconstriction was deduced from the medial thickness which was measured and expressed as a percentage of external diameter. Six pigs received oleic acid (0.12 +/- 0.07 ml/kg), dissolved 1:1 in 96% alcohol, in multiple injections of 0.1 ml. Six pigs were used as controls. After the oleic acid injections a stable hypoxaemia (PaO2 = 57 +/- 8 mmHg, at an inspiratory oxygen fraction of 0.6) and pulmonary hypertension (mean Ppa = 36 +/- 2 mmHg) were obtained for several hours. Electron microscopy revealed swelling of endothelial cells with signs of degeneration. Medial thickness was far greater in the oleic acid group than in the control group; overall mean values were 8.1 +/- 3.2 and 3.8 +/- 1.7% respectively (P < 0.001). Arteries with prominent vasoconstriction were lying in clusters. This pattern was the same in dependent and non-dependent regions. We concluded that in oleic acid induced respiratory distress active vasoconstriction of muscular pulmonary arteries is an important factor in the development of pulmonary hypertension. Besides vasoconstriction, endothelial swelling and intravascular clotting may contribute to the development of pulmonary hypertension. Images Figure 1 Figure 2 Figure 3

Grotjohan, H. P.; van der Heijde, R. M.; Wagenvoort, C. A.; Wagenvoort, N.; Versprille, A.

1993-01-01

434

Viscoelastic properties and fractal analysis of acid-induced SPI gels at different ionic strength.  

PubMed

The viscoelastic property and scaling behavior of acid (glucono-?-lactone)-induced soy protein isolate (SPI) gels were investigated at various ionic strengths (0-800mM) and five protein concentrations ranging between 4% and 8% (w/w). The infinite storage modulus ( [Formula: see text] ) and the gelation start time (t(g)) which indicate the progress of gelation process exhibited strong ionic strength dependence. The storage modulus and critical strain were found to exhibit a power-law relationship with protein concentration. Rheological analysis and confocal laser scanning microscopy (CLSM) analysis were applied to estimate the fractal dimensions (D(f)) of the gels and the values were found to vary between 2.319 and 2.729. The comparison of the rheological methods and the CLSM image analysis method showed that the Shih, Shih, Kim, Liu, and Aksay (1990) model was better suited in estimating the D(f) value of acid-induced SPI gel system. PMID:23218271

Bi, Chong-hao; Li, Dong; Wang, Li-jun; Adhikari, Benu

2013-01-30

435

RNA helicase retinoic acid-inducible gene I as a sensor of Hantaan virus replication.  

PubMed

Hantaan virus (HTNV) causes severe human disease. The HTNV genome consists of three ssRNA segments of negative polarity that are complexed with viral nucleocapsid (N) protein. How the human innate immune system detects HTNV is unclear. RNA helicase retinoic acid-inducible gene I (RIG-I) does not sense genomic HTNV RNA. So far it has not been analysed whether pathogen-associated molecular patterns generated during the HTNV replication trigger RIG-I-mediated innate responses. Indeed, we found that knock-down of RIG-I in A549 cells, an alveolar epithelial cell line, increases HTNV replication and prevents induction of 2',5'-oligoadenylate synthetase, an interferon-stimulated gene. Moreover, overexpression of wild-type or constitutive active RIG-I in Huh7.5 cells lacking a functional RIG-I diminished HTNV virion production. Intriguingly, reporter assays revealed that in vitro-transcribed HTNV N RNA and expression of the HTNV N ORF triggers RIG-I signalling. This effect was completely blocked by the RNA-binding domain of vaccinia virus E3 protein, suggesting that dsRNA-like secondary structures of HTNV N RNA stimulate RIG-I. Finally, transfection of HTNV N RNA into A549 cells resulted in a 2 log-reduction of viral titres upon challenge with virus. Our study is the first demonstration that RIG-I mediates antiviral innate responses induced by HTNV N RNA during HTNV replication and interferes with HTNV growth. PMID:21632559

Lee, Min-Hi; Lalwani, Pritesh; Raftery, Martin J; Matthaei, Markus; Lütteke, Nina; Kirsanovs, Sina; Binder, Marco; Ulrich, Rainer G; Giese, Thomas; Wolff, Thorsten; Krüger, Detlev H; Schönrich, Günther

2011-09-01

436

Mapping and reconstruction of domoic acid-induced neurodegeneration in the mouse brain.  

PubMed

Domoic acid, a potent neurotoxin and glutamate analog produced by certain species of the marine diatom Pseudonitzschia, is responsible for several human and wildlife intoxication events. The toxin characteristically damages the hippocampus in exposed humans, rodents, and marine mammals. Histochemical studies have identified this, and other regions of neurodegeneration, though none have sought to map all brain regions affected by domoic acid. In this study, mice exposed (i.p.) to 4 mg/kg domoic acid for 72 h exhibited behavioral and pathological signs of neurotoxicity. Brains were fixed by intracardial perfusion and processed for histochemical analysis. Serial coronal sections (50 microm) were stained using the degeneration-sensitive cupric silver staining method of DeOlmos. Degenerated axons, terminals, and cell bodies, which stained black, were identified and the areas of degeneration were mapped onto Paxinos mouse atlas brain plates using Adobe Illustrator CS. The plates were then combined to reconstruct a 3-dimensional image of domoic acid-induced neurodegeneration using Amira 3.1 software. Affected regions included the olfactory bulb, septal area, and limbic system. These findings are consistent with behavioral and pathological studies demonstrating the effects of domoic acid on cognitive function and neurodegeneration in rodents. PMID:16109471

Colman, J R; Nowocin, K J; Switzer, R C; Trusk, T C; Ramsdell, J S

2005-01-01

437

Inner ear tissue remodeling and ion homeostasis gene alteration in murine chronic otitis media  

PubMed Central

Hypothesis Studies were designed to ascertain the impact of chronic middle ear infection on the numerous ion and water channels, transporters and tissue remodeling genes in the inner and middle ear. Background Permanent sensorineural hearing loss is a significant problem resulting from chronic middle ear disease, although the inner ear processes involved are poorly defined. Maintaining a balanced ionic composition of endolymph in the inner ear is crucial for hearing, thus, it was hypothesized this may be at risk with inflammation. Methods Inner and middle ear RNA collected separately from 6 month-old C3H/HeJ mice with prolonged middle ear disease were subjected to qRT-PCR for 8 common inflammatory cytokine genes, 24 genes for channels controlling ion (sodium, potassium, chloride) and water (aquaporin) transport, tight junction claudins, and gap junction connexins, and 32 tissue remodeling genes. Uninfected Balb/c mice were used as controls. Results Significant increase in inner ear inflammatory and ion homeostasis (claudin, aquaporin and gap junction) gene expression, and both up- and down-regulation of tissue remodeling gene expression occurred. Alteration in middle ear ion homeostasis and tissue remodeling gene expression was noted in the setting of uniform upregulation of cytokine genes. Conclusions Chronic inflammatory middle ear disease can impact inner ear ion and water transport functions and induce tissue remodeling. Recognizing these inner ear mechanisms at risk may identify potential therapeutic targets to maintain hearing during prolonged otitis media.

MacArthur, Carol J.; Hausman, Fran; Kempton, J. Beth; Sautter, Nathan; Trune, Dennis R.

2012-01-01

438

The clinical implications of ear canal debris in hearing aid users.  

PubMed

Objective : The ear irritations suffered by hearing aid (HA) users are yet to be related to the clinical state of canal. We undertook this study to examine the nature of debris and the microbial flora of ears of hearing aid users, as well as evaluate the determinant factors of ear irritation in this population. Methods : An observational clinical study was carried out involving 32 unilateral hearing aid users recruited from ENT clinic of a tertiary referral center. Each subject underwent otoscopic assessment of canal debris and microbial analysis of swab cultures taken from the hearing aid-wearing ear and contralateral normal ear without hearing aid. Results : Canal debris [wax (28%), fungal deposits (19%), bacteria exudates (13%)]. as well as microorganisms were identified in significant number of ears with hearing aids than ears without hearing aid (P = 0.003 and P = 0.006 respectively). Coagulase-negative staphylococci were the commonest identified bacteria. Others were Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus species. Intolerable irritations of hearing aid wearing ears were significantly associated with bacterial and fungal otitis externa, and ear discharge (P = 0.005, 0.02, 0.03 respectively). Conclusions : This study demonstrates that using hearing aid alters the ear canal flora; increases risk of both fungal and bacterial otitis externa, as well as encourage wax debris formation, with resultant ear irritations. To ensure compliance their ears should periodically be attended to, by de-waxing or given topical antimicrobial agents where indicated. PMID:24948963

Orji, Foster Tochukwu; O Onyero, Emmanuel; Agbo, Christian Ejiofor

2014-05-01

439

Brain power - borrowing from biology makes for low power computing [bionic ear  

Microsoft Academic Search

This paper describes the recent advances in the field of neuromorphic engineering, more generally, biologically inspired electronics. This paper focuses on the work being done to develop bionic ears. A key area of interest is understanding the scheme that allows low-power analog processing in the ear followed by digitization. Researchers at MIT have developed a bionic ear processor that does

R. Sarpeshkar

2006-01-01

440

Narrow-Band Evoked Oto-Acoustic Emission from Ears with Normal and Pathologic Conditions  

Microsoft Academic Search

Conclusion: Evoked oto-acoustic emission (EOAE), in particular the slow component, is fragile with the inner ear lesions and is apt to disappear in impaired ears. This presence is thought to mean that inner ear is not badly damaged, and that the presence of EOAEs in early stage sudden deafness carries a good prognosis. Narrow-band EOAE analysis would open a potentially

Taizo Takeda; Akinobu Kakigi; Shinji Takebayashi; Satoshi Ohono; Rie Nishioka; Hiroaki Nakatani

2009-01-01

441

Multi-view ear recognition based on B-Spline pose manifold construction  

Microsoft Academic Search

In this work, multi-view ear recognition problems are examined in detail. A new multi-view ear recognition approach based on B-Spline pose manifold construction in discriminative projection space which is formed by null kernel discriminant analysis (NKDA) feature extraction is presented. Many experiments and comparisons are provided to show the effectiveness of our multi-view ear recognition approach.

Zhiyuan Zhang; Heng Liu

2008-01-01

442

The clinical implications of ear canal debris in hearing aid users  

PubMed Central

Objective : The ear irritations suffered by hearing aid (HA) users are yet to be related to the clinical state of canal. We undertook this study to examine the nature of debris and the microbial flora of ears of hearing aid users, as well as evaluate the determinant factors of ear irritation in this population. Methods : An observational clinical study was carried out involving 32 unilateral hearing aid users recruited from ENT clinic of a tertiary referral center. Each subject underwent otoscopic assessment of canal debris and microbial analysis of swab cultures taken from the hearing aid-wearing ear and contralateral normal ear without hearing aid. Results : Canal debris [wax (28%), fungal deposits (19%), bacteria exudates (13%)]. as well as microorganisms were identified in significant number of ears with hearing aids than ears without hearing aid (P = 0.003 and P = 0.006 respectively). Coagulase-negative staphylococci were the commonest identified bacteria. Others were Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus species. Intolerable irritations of hearing aid wearing ears were significantly associated with bacterial and fungal otitis externa, and ear discharge (P = 0.005, 0.02, 0.03 respectively). Conclusions : This study demonstrates that using hearing aid alters the ear canal flora; increases risk of both fungal and bacterial otitis externa, as well as encourage wax debris formation, with resultant ear irritations. To ensure compliance their ears should periodically be attended to, by de-waxing or given topical antimicrobial agents where indicated.

Orji, Foster Tochukwu; O. Onyero, Emmanuel; Agbo, Christian Ejiofor

2014-01-01

443

An ultrastructural study on the ear cartilage of rabbits after the administration of papain  

Microsoft Academic Search

Summary Crude papain was administered intravenously to young rabbits and the cartilage of the collapsed ear was examined electron-microscopically. Degeneration and recovery of chondrocytes, and decrease in and recovery of the electron-density of elastic fibers, were observed during the collapse and restoration of the ear. Some samples were stained with ruthenium red. In the collapsed ear, with a marked decrease

Michiko Ueda; Mitsuhiko Kitaoka; Shunsuke Inouye; Gentaro Usuku

1981-01-01

444