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1

Effects of indole-3-acetic acid on croton oil- and arachidonic acid-induced mouse ear edema  

Microsoft Academic Search

The indole-3-acetic acid (IAA) is a plant growth hormone (auxin) being considered as a tryptophan metabolite in animals. The main purpose of this work was to verify IAA's topical anti-inflammatory action using croton oil- or arachidonic acid-induced mouse ear edema, in comparison to known anti-inflammatory agents. IAA antioxidant activity was also verified by measuring the inhibition of brain homogenate lipid

L. H. Jones; D. S. P. Abdalla; J. C. Freitas

1995-01-01

2

Tachyphylaxis in 12-0-Tetradecanoylphorbol Acetate and Arachidonic Acid-Induced Ear Edema  

Microsoft Academic Search

12-0-Tetradecanoylphorbol acetate (TPA) applied to mouse ears rapidly induces an edema which is maximal by 6 hr but has substantially waned by 24 hr. (This is in contrast to many inflammatory agents that cause a prolonged edema lasting many days.) Reapplication of TPA at 16-24 hr will not provoke a second edematous response although increased erythema is evident. Arachidonic acid

John M. Young; Bonnie M. Wagner; Doreen A. Spires

1983-01-01

3

The Mouse Ear Inflammatory Response to Topical Arachidonic Acid  

Microsoft Academic Search

Application of arachidonic acid (AA) (0.1–4 mg) to the ears of mice produces immediate vasodilatation and erythema (5 min) followed by the abrupt development of edema which is maximal at 40–60 min. The onset of edema coincides with extravasation of protein and leukocytes. After 1 h, the edema begins to wane rapidly and the inflammatory cells leave the tissue so

John M. Young; Doreen A. Spires; Charles J. Bedord; Bonnie Wagner; Stephen J. Ballaron; Lawrence M. de Young

1984-01-01

4

Prostaglandin and Leukotriene Synthesis in Mouse Ears Inflamed by Arachidonic Acid  

Microsoft Academic Search

Topical application of arachidonic acid on mouse ears induces the synthesis of prostaglandin E2 and leukotrienes C4 and D4. The increased tissue levels of these products are quantitated by radioimmunoassay. The identity of the leukotrienes was confirmed by immunoreactivity of reverse-phase high-performance liquid chromatography fractions corresponding to authentic standards. Synthesis of the arachidonic acid metabolites precedes or is coincident with

Evan E. Opas; Robert J. Bonney; John L. Humes

1985-01-01

5

Arachidonic acid-induced expression of the organic solute and steroid transporter-beta (Ost-beta) in a cartilaginous fish cell line.  

PubMed

The organic solute and steroid transporter (OST/Ost) is a unique membrane transport protein heterodimer composed of subunits designated alpha and beta, that transports conjugated steroids and prostaglandin E(2) across the plasma membrane. Ost was first identified in the liver of the cartilaginous fish Leucoraja erinacea, the little skate, and subsequently was found in many other species, including humans and rodents. The present study describes the isolation of a new cell line, LEE-1, derived from an early embryo of L. erinacea, and characterizes the expression of Ost in these cells. The mRNA size and amino acid sequence of Ost-beta in LEE-1 were identical to that previously reported for Ost-beta from skate liver, and the primary structure was identical to that of the spiny dogfish shark (Squalus acanthias) with the exception of a single amino acid. Ost-beta was found both on the plasma membrane and intracellularly in LEE-1 cells, consistent with its localization in other cell types. Interestingly, arachidonic acid, the precursor to eicosanoids, strongly induced Ost-beta expression in LEE-1 cells and a lipid mixture containing arachidonic acid also induced Ost-alpha. Overall, the present study describes the isolation of a novel marine cell line, and shows that this cell line expresses relatively high levels of Ost when cultured in the presence of arachidonic acid. Although the function of this transport protein in embryo-derived cells is unknown, it may play a role in the disposition of eicosanoids or steroid-derived molecules. PMID:18407792

Hwang, Jae-Ho; Parton, Angela; Czechanski, Anne; Ballatori, Nazzareno; Barnes, David

2008-03-12

6

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

7

ROLE OF INTRACELLULAR CALCIUM AND PHOSPHOLIPASE A2 IN ARACHIDONIC ACID-INDUCED TOXICITY IN LIVER CELLS OVEREXPRESSING CYP2E1*  

PubMed Central

Liver cells (HepG2 and primary hepatocytes) overexpressing CYP2E1 and exposed to arachidonic acid (AA) were previously shown to lose viability together with enhanced lipid peroxidation. These events were blocked in cells pre-incubated with antioxidants (? -tocopherol, glutathione ethyl ester), or in HepG2 cells not expressing CYP2E1. The goal of the current study was to evaluate the role of calcium and calcium-activated hydrolases in these CYP2E1-AA interactions. CYP2E1-expressing HepG2 cells treated with AA showed an early increase in cytosolic calcium and partial depletion of ionomycin-sensitive calcium stores. These changes in calcium were blocked by ? -tocopherol. AA activated phospholipase A2 (PLA2) in CYP2E1-expressing liver cells, and this was inhibited by PLA2 inhibitors or ? -tocopherol. PLA2 inhibitors prevented the cell death caused by AA, without affecting CYP2E1 activity or lipid peroxidation. AA toxicity and PLA2 activation were inhibited in calcium-depleted cells, but not by removal of extracellular calcium alone. Removal of extracellular calcium inhibited the early increase in cytosolic calcium caused by AA. CYP2E1 overexpressing HepG2 cells exposed to AA showed a decrease in mitochondrial membrane potential, which was prevented by the PLA2 inhibitors. These results suggest that AA-induced toxicity to CYPE1-expressing cells: (i) is associated with release of Ca2+ from intracellular stores that depends mainly on oxidative membrane damage; (ii) is associated with activation of PLA2 that depends on intracellular calcium and lipid peroxidation; iii) does not depend on increased influx of extracellular calcium, and iv) depends on the effect of converging events (lipid peroxidation, intracellular calcium, activation of PLA2) on mitochondria to induce bioenergetic failure and necrosis. These interactions may play a role in alcohol liver toxicity, which requires polyunsaturated fatty acids, and involves induction of CYP2E1.

Caro, Andres A.; Cederbaum, Arthur I.

2007-01-01

8

Changes in Arachidonic Acid Metabolite Patterns in Alloxan-Induced Diabetic Rats  

Microsoft Academic Search

The vasodepressor responses to intravenous injections of arachidonic acid, and the formation of its metabolites, were studied in rats made diabetic 1 or 2 weeks after a 1-dose alloxan treatment. Arachidonic acid dose-dependently decreased the diastolic blood pressure in normal animals, but this hypotensive effect was significantly weaker in 2-week postalloxan-treated rats. Indometacin abolished arachidonic-acid-induced depressor responses in both normal

S.-C. G. Hui; C. W. Ogle; Z. Wang; Y. An; Y.-H. Hu

1989-01-01

9

A possible role of arachidonic acid in human neutrophil aggregation and degranulation.  

PubMed Central

Chemotactic factors stimulate neutrophils to aggregate and, in the presence of cytochalasin B, to degranulate. Recently, the authors found that arachidonic acid also stimulates human neutrophils to aggregate but does not stimulate cytochalasin-B-treated or untreated cells to degranulate. In this report the authors examined the effect of three blockers of arachidonic acid metabolism on these cellular responses. It was found that the arachidonic acid analog 5,8,11,14-eicosatetraynoic acid and indomethacin, but not aspirin, inhibited no only the arachidonic-acid-induced aggregation response but also the degranulation responses evoked by C5a or a synthetic oligopeptide chemotactic factor. These results suggest that arachidonic acid may be a precursor of bioactive metabolites that stimulate the aggregation and foster the degranulation responses of neutrophils. Thus, these metabolites may be mediators of neutrophil function. Agents that block their formation may thereby inhibit aggregation and degranulation.

O'Flaherty, J. T.; Showell, H. J.; Ward, P. A.; Becker, E. L.

1979-01-01

10

Swimmer's Ear  

MedlinePLUS

... get swimmer's ear from taking baths or showers. Bacteria get a chance to grow when water stays in the ear canal. A lot of swimming can lead to these wet conditions in the ear canal. Bacteria grow and the ear canal gets red and ...

11

Ear barotrauma  

MedlinePLUS

Barotitis media; Barotrauma; Ear popping; Pressure-related ear pain; Eustachian tube dysfunction ... The air pressure in the middle ear is usually the same as the air pressure outside of the body. The eustachian tube is a connection between the middle ear ...

12

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

13

Ear Anatomy  

Microsoft Academic Search

\\u000a The ear is divided into three compartments: external, middle, and inner. The eustachian tube connects the middle ear to the\\u000a nasopharynx. The external and middle ear develop from the branchial apparatus. The middle ear cavity is derived from the endodermal\\u000a first branchial cleft. The inner ear develops from the otic placode. The footplate of the stapes is derived from the

T. Metin Önerci

14

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 ...

15

Ear Tumors  

MedlinePLUS

... and causing hearing loss and a buildup of earwax. Such tumors include small sacs filled with skin ... ear. Ceruminoma (cancer of the cells that produce earwax) develops in the outer third of the ear ...

16

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 ...

17

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

18

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 ...

19

Arachidonic Acid Activates c-Jun N-Terminal Kinase through NADPH Oxidase in Rabbit Proximal Tubular Epithelial Cells  

Microsoft Academic Search

In kidney epithelial cells, arachidonic acid and other fatty acids are important signal transduction molecules for G protein-coupled receptors. We now demonstrate that arachidonic acid induced a time- and dose-dependent activation of JNK, a member of the mitogenactivated protein kinase family, as assessed by phosphorylation of the transcription factor ATF-2. Increments in JNK activity were detectable at 5 mu M

Xiao-Lan Cui; Janice G. Douglas

1997-01-01

20

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

21

Your Ears  

MedlinePLUS

... fluid in the semicircular canals stops moving, your brain gets the right message and you regain your balance. Three Cheers for the Ears! Your ears take care of you, so take care of them. Protect your hearing by wearing earplugs at loud music concerts and around noisy machinery, like in wood ...

22

Ear concha.  

PubMed

This article classifies man's ear concha to defined shape groups where the concha is the hollow area next to the ear canal. Quantitative results about the ear concha shapes as well as their classification into 36 defined shape groups are also reported. This quantitative survey is an additional step in analyzing the shape of face parts, where, in a article published in The Journal of Craniofacial Surgery (2011;22:1-4), nose shapes were analyzed quantitatively and classified into 14 shapes. It should be noted that in Google, under the subject, "Tamir the Journal of Craniofacial Surgery," the survey about noses is mentioned about 120 times! To the best of the author's knowledge, the quantitative approach on the shapes of ear concha has never been implemented before. The results are based on 2425 pictures of real ears. The major results are as follows: (1) The author succeeded in classifying all subjects' ear concha into 36 groups as demonstrated in a figure (numbers in the bottom left of each image are the absolute number of concha of a certain type; those in the bottom right indicate the percentage). (2) The most widespread concha is number 29, which appeared 393 times and is 16.2% of the total number. The less widespread shape is number 34, which appeared only once (0.04% of the total). In addition to the numerical results, the subjects were evaluated with respect to a human's ear--anatomy, shapes, and relation to a human's character. PMID:22421843

Tamir, Abraham

2012-03-01

23

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

24

Ear emergencies  

MedlinePLUS

... and ruptured eardrums can be caused by: Inserting cotton swabs, toothpicks, pins, pens, or other objects into ... The person will have severe pain. Place sterile cotton gently in the outer ear canal to keep ...

25

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

26

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

27

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

28

Ear Injuries (For Parents)  

MedlinePLUS

... Inserting something into the ear. Things like a cotton swab, fingernail, or pencil can scratch the ear ... Never stick anything in their ears — not even cotton swabs or their fingers. Regular bathing should be ...

29

Middle Ear Infections (For Parents)  

MedlinePLUS

... a foreign object in the ear, or hard earwax. Consult your doctor to help determine the cause ... Surgery Ototoxicity (Ear Poisoning) Ear Injuries Dealing With Earwax Swimmer's Ear (Otitis Externa) What Is an Ear ...

30

Ear drainage culture  

MedlinePLUS

... needed. Your health care provider will use a cotton swab to collect the sample from inside the ... No pain is associated with using a cotton swab to take a sample of drainage from the outer ear. However, ear pain may be present if the ear is infected. Ear ...

31

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

32

Butyric Acid Induces Apoptosis in Inflamed Fibroblasts  

Microsoft Academic Search

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

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

2008-01-01

33

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

34

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, ...

35

Otoplasty (Cosmetic Ear Surgery)  

MedlinePLUS

... CLICK TO ENLARGE Otoplasty Otoplasty — also known as cosmetic ear surgery — is a procedure to change the ... Society of Plastic Surgeons. http://www.plasticsurgery.org/Cosmetic-Procedures/Ear-Surgery.html. Accessed June 22, 2012. ...

36

Ear surgery - series (image)  

MedlinePLUS

... expose the ear cartilage. Sutures are used to fold the cartilage to reshape the ear. Other surgeons ... to the head by creating a more pronounced fold (called the antihelix) in the central portion of ...

37

Swimmer's Ear (External Otitis)  

MedlinePLUS

... ears. This is especially true if they use cotton-tipped applicators or dangerously sharp small objects, like ... all objects out of your ear canals — including cotton-tipped applicators — unless your doctor has told you ...

38

Flying and Your Child's Ears  

MedlinePLUS

... Tips for Easing Ear Pain Flying's Effects on Ears Many of us have felt that weird ear- ... equalization happen more easily. Continue Tips for Easing Ear Pain Some simple things to try during air ...

39

Inhibition of arachidonic acid release as the mechanism by which glucocorticoids inhibit endotoxin-induced diarrhoea.  

PubMed Central

1 Dexamethasone blocked endotoxin-induced diarrhoea in mice, but not that induced by arachidonic acid or prostaglandin E2. 2 Indomethacin blocked endotoxin and arachidonic acid-induced diarrhoea, but not that induced by prostaglandin E2. 3 Codeine blocked all three forms of diarrhoea. 4 The above data, when considered in relation to literature reports that endotoxin induces prostaglandin synthesis, suggest that dexamethasone blocks diarrhoea by preventing the release of arachidonic acid, the substrate for prostaglandin biosynthesis. 5 The activities of indomethacin and dexamethasone in castor oil diarrhoea support the above conclusion and their inactivity in 5-hydroxytryptophan-induced diarrhoea confirms the absence of 'codeine-like' direct effects on the gut. 6 Other glucocorticoids (hydrocortisone, prednisolone) were also able to block endotoxin diarrhoea, but oestradiol, testosterone and progesterone did not. 7 The inhibitory action of dexamethasone on endotoxin diarrhoea could not be blocked by the protein synthesis inhibitor, cycloheximide, nor by the glucocorticoid receptor antagonist, progesterone. Thus, involvement of glucocorticoid receptor-mediated gene activation could not be demonstrated.

Doherty, N. S.

1981-01-01

40

Arachidonate metabolism in bovine gallbladder muscle  

SciTech Connect

Incubation of (1-/sup 14/C)arachidonic acid (AA) with homogenates of bovine gallbladder muscle generated a large amount of radioactive material having the chromatographic mobility of 6-keto-PGF1 alpha (stable product of PGI2) and smaller amounts of products that comigrated with PGF2 alpha PGE2. Formation of these products was inhibited by the cyclooxygenase inhibitor indomethacin. The major radioactive product identified by thin-layer chromatographic mobility and by gas chromatography - mass spectrometric analysis was found to be 6-keto-PGF1 alpha. The quantitative metabolic pattern of (1-/sup 14/C)PGH2 was virtually identical to that of (1-/sup 14/C)AA. Incubation of arachidonic acid with slices of bovine gallbladder muscle released labile anti-aggregatory material in the medium, which was inhibited by aspirin or 15-hydroperoxy-AA. These results indicate that bovine gallbladder muscle has a considerable enzymatic capacity to produce PGI2 from arachidonic acid.

Nakano, M.; Hidaka, T.; Ueta, T.; Ogura, R.

1983-04-01

41

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

42

Ear localization using hierarchical clustering  

Microsoft Academic Search

Ear biometrics has been found to be a good and reliable technique for human recognition. With the initial doubts on uniqueness of the ear, ear biometrics could not attract much attention. But after it has been said that it is almost impossible to find two ears with all the parts identical, ear biometrics has gained its pace. To automate the

Surya Prakash; Umarani Jayaraman; Phalguni Gupta

2009-01-01

43

Middle Ear Infections and Ear Tube Surgery (For Parents)  

MedlinePLUS

... atmospheric pressure in the middle ear. About Otitis Media The middle ear is an air-filled cavity ... learning. Continue Symptoms and Diagnosis Symptoms of otitis media include: pulling or rubbing the ears because of ...

44

Autoimmune Inner Ear Disease (AIED)  

MedlinePLUS

Autoimmune Inner Ear Disease What is autoimmunity? How is it connected to vestibular disorders? Parts of the immune system, working constantly ... reaction. The immune system can attack just the ear, attack the ear and some other body part ...

45

Ear - blocked at high altitudes  

MedlinePLUS

High altitudes and blocked ears; Flying and blocked ears; Eustachian tube dysfunction -high altitude ... opens the Eustachian tube, which connects the middle ear to the nose. These movements allow the pressure ...

46

Sound Conduction of the Ear.  

National Technical Information Service (NTIS)

Development of the cochlear potential method for study of conductive processes in the ear, and experiments showing the action of the middle ear and cochlear mechanisms, have added substantially to our understanding of the ear under normal and pathological...

E. G. Wever

1974-01-01

47

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 ...

48

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

49

Licofelone attenuates quinolinic acid induced Huntington like symptoms: possible behavioral, biochemical and cellular alterations.  

PubMed

Cyclo-oxygenase and lipoxygenase enzymes are involved in arachidonic acid metabolism. Emerging evidence indicates that cyclo-oxygenase and lipoxygenase inhibitors prevent neurodegenerative processes and related complications. Therefore, the present study has been designed to explore the neuroprotective potential of licofelone (dual COX-2/5-LOX inhibitor) against quinolinic acid induced Huntington like symptom in rats. Intrastriatal administration of quinolinic acid significantly caused reduction in body weight and motor function (locomotor activity, rotarod performance and beam walk test), oxidative defense (as evidenced by increased lipid peroxidation, nitrite concentration and decreased endogenous antioxidant enzymes), alteration in mitochondrial enzyme complex (I, II and IV) activities, raised TNF-? level and striatal lesion volume as compared to sham treated animals. Licofelone (2.5, 5 and 10 mg/kg) treatment significantly improved body weight, locomotor activity, rotarod performance, balance beam walk performance, oxidative defense, mitochondrial enzyme complex activities and attenuated TNF-? level and striatal lesion as compared to control (quinolinic acid). The present study highlights that licofelone attenuates behavioral, biochemical and cellular alterations against quinolinic acid induced neurotoxicity and this could be an important therapeutic avenue to ameliorate the Huntington like symptoms. PMID:21237233

Kalonia, Harikesh; Kumar, Puneet; Kumar, Anil

2011-01-13

50

Ethanolic extract of Piper betle Linn. leaves reduces nociception via modulation of arachidonic acid pathway  

PubMed Central

Objectives: The objective of this study was to evaluate the peripheral analgesic effect of Piper betle leaf extract (PBE) along with establishing its putative mechanism of action. Materials and Methods: Male Swiss albino mice after pre-treatment (1 h) with different doses of PBE were injected 0.8% (v/v) acetic acid i.p.; the onset and number of writhes were noted up to 15 min. To evaluate the mechanism of action, the murine peritoneal exudate was incubated with PBE for 1 h, followed by exposure to arachidonic acid (AA) and generation of reactive oxygen species (ROS) was measured by flow cytometry using 2’,7’-dichlorodihydrofluorescein diacetate. Results: PBE in a dose dependent manner significantly reduced acetic acid induced writhing response in mice (P < 0.001). In peritoneal exudates, PBE significantly inhibited AA induced generation of ROS, P < 0.01. Conclusions: The present study indicates that PBE has promising analgesic activity, worthy of future pharmacological consideration.

De, Soumita; Maroo, Niteeka; Saha, Piu; Hazra, Samik; Chatterjee, Mitali

2013-01-01

51

Prostaglandin synthase 1 gene disruption in mice reduces arachidonic acid-induced inflammation and indomethacin-induced gastric ulceration  

Microsoft Academic Search

Cyclooxygenases 1 and 2 (COX-1 and COX-2) are key enzymes in prostaglandin biosynthesis and the target enzymes for the widely used nonsteroidal anti-inflammatory drugs. To study the physiological roles of the individual isoforms, we have disrupted the mouse Ptgs1 gene encoding COX-1. Homozygous Ptgs1 mutant mice survive well, have no gastric pathology, and show less indomethacin-induced gastric ulceration than wild-type

Robert Langenbach; Scott G. Morham; Howard F. Tiano; Charles D. Loftin; Burhan I. Ghanayem; Patricia C. Chulada; Joel F. Mahler; Christopher A. Lee; Eugenia H. Goulding; Kimberly D. Kluckman; H. S. Kim; Oliver Smithies

1995-01-01

52

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

53

BIOMECHANICAL STUDY OF MIDDLE EAR  

Microsoft Academic Search

Summary. The human ear is a complex biomechanical system and is divided by three parts: outer, middle and inner ear. The middle ear is formed by three ossicles (malleus, incus and stapes) that amplify the sound sending the sound waves to the inner ear. However, the ossicles can suffer from several damages, for example, the Otosclerosis, being a need the

M Moreira; E Almeida

54

Sports Injuries of the Ear  

PubMed Central

The author describes common sports injuries involving the ear. Such injuries include hematoma, lacerations, foreign bodies (tattoo), and thermal injuries. Ear canal injuries include swimmer's ear and penetrating injuries. Tympanum injuries include tympanic membrane perforations, ossicular discontinuity, eustachian tube dysfunction, temporal bone fractures and traumatic facial nerve palsy. Inner ear injuries include traumatic sensorineural deafness. The author emphasizes the management of these injuries.

Wagner, G. A.

1972-01-01

55

Ear Plastic Surgery (Otoplasty)  

MedlinePLUS

... can have an artificial ear surgically attached for cosmetic reasons. These are custom formed to match the ... child will experience the psychological benefits of the cosmetic improvement. However, a patient may have the surgery ...

56

Cleaning Your Ears  

MedlinePLUS

... Anything In The Ear Canal This means no cotton swabs, no fingers and certainly no sharp objects, ... the opposite result — rather than removing earwax, a cotton swab or other object often will push wax ...

57

Effect of prostaglandin, leukotriene, and arachidonic acid on experimental otitis media with effusion in chinchillas.  

PubMed

Although previous studies have shown that prostaglandins (PGs), leukotrienes (LTs), and other arachidonic acid (AA) metabolites play an important role in the pathogenesis of otitis media with effusion (OME), the exact role of each AA metabolite in OME is still unknown. The purpose of this study was to examine the effect of several individual AA metabolites alone or in combination and AA itself on experimental otitis media in chinchillas. Normal chinchillas were inoculated daily with normal saline, PGE2, LTC4, LTC4 + PGE2, and AA through the superior bullae over 7 days. Animals were followed by otoscopy and tympanometry, samples of middle ear effusion were collected for biochemical assay, and temporal bones were processed for histopathology. The highest number of ears that developed OME was in the group inoculated with PGE2 + LTC4. The degree of inflammatory change was more pronounced in groups injected with LTC4 than any other group. The findings of this study suggest that eicosanoids PGE2, LTC4, and AA alone or in combination inoculated into the middle ear can induce OME. PMID:2161636

Jung, T T; Park, Y M; Schlund, D; Weeks, D; Miller, S; Wong, O; Juhn, S K

1990-06-01

58

External and middle ear trauma resulting from ear impressions.  

PubMed

When taking an impression of the external ear canal and ear, the audiologist is engaged in an invasive procedure whereby a foreign body is first placed into the ear canal and then removed. There is always an element of risk for significant medical problems when a clinician is performing an invasive procedure. Although some minor patient discomfort and, at times, some slight trauma to the ear canal occur when taking ear impressions, the incidence of significant trauma to the external or middle ear appears to be low. The purpose of this report is to provide some illustrative cases of significant external and middle ear trauma as a result of taking impressions of the external ear. Audiologists are advised to develop and implement an appropriate risk management program for taking ear impressions to reduce the potential risks associated with this procedure to their patients and to their practices. PMID:10976496

Wynne, M K; Kahn, J M; Abel, D J; Allen, R L

59

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...

60

Relationship between arachidonate generation and exocytosis in permeabilized mast cells.  

PubMed Central

Using rat mast cells permeabilized with streptolysin O we show that release of arachidonate generally occurs under similar but not identical conditions to those that cause exocytosis of beta-N-acetylglucosaminidase (hexosaminidase). Thus, hexosaminidase secretion and arachidonate release both require provision of Ca2+ together with a guanine nucleotide but exocytosis occurs at lower concentrations of both effectors. The kinetics of both processes are similar, with a delay in onset only when ATP is present. Arachidonate release occurs largely from a pool of arachidonyl phosphatidylcholine which appears to represent less than 1% of the total phosphatidylcholine of the cells. Despite the general similarity of the conditions causing exocytosis and arachidonate release, our results show that under some circumstances it is possible to obtain exocytosis without measurable release of arachidonate and that therefore phospholipase A2 activation is not an essential precursor of secretion.

Churcher, Y; Allan, D; Gomperts, B D

1990-01-01

61

Listening to the ear  

NASA Astrophysics Data System (ADS)

Otoacoustic emissions demonstrate that the ear creates sound while listening to sound, offering a promising acoustic window on the mechanics of hearing in awake, listening human beings. That window is clouded, however, by an incomplete knowledge of wave reflection and transmission, both forth and back within the cochlea and through the middle ear. This thesis "does windows," addressing wave propagation and scattering on both sides of the middle ear. A summary of highlights follows. Measurements of the cochlear input impedance in cat are used to identify a new symmetry in cochlear mechanics-termed "tapering symmetry" after its geometric interpretation in simple models-that guarantees that the wavelength of the traveling wave changes slowly with position near the stapes. Waves therefore propagate without reflection through the basal turns of the cochlea. Analytic methods for solving the cochlear wave equations using a perturbative scattering series are given and used to demonstrate that, contrary to common belief, conventional cochlear models exhibit negligible internal reflection whether or not they accurately represent the tapering symmetries of the inner ear. Frameworks for the systematic "deconstruction" of eardrum and middle-ear transduction characteristics are developed and applied to the analysis of noninvasive measurements of middle-ear and cochlear mechanics. A simple phenomenological model of inner-ear compressibility that correctly predicts hearing thresholds in patients with missing or disarticulated middle-ear ossicles is developed and used to establish an upper bound on cochlear compressibility several orders of magnitude smaller than that provided by direct measurements. Accurate measurements of stimulus frequency evoked otoacoustic emissions are performed and used to determine the form and frequency variation of the cochlear traveling-wave ratio noninvasively. Those measurements are inverted to obtain the spatial distribution of mechanical inhomogeneities responsible for evoked emission. Although current models require that the periodicities found in emission spectra and threshold hearing curves originate in a corresponding corrugation in the mechanics of the cochlea, it is shown that the observed spectral periodicities can arise spontaneously through the dynamics of wave propagation and reflection and that the organ of Corti, as suggested by the anatomy, need manifest no particular translational symmetries.

Shera, Christopher A.

62

Listening to the Ear  

NASA Astrophysics Data System (ADS)

Otoacoustic emissions demonstrate that the ear creates sound while listening to sound, offering a promising acoustic window on the mechanics of hearing in awake, listening human beings. That window is clouded, however, by an incomplete knowledge of wave reflection and transmission, both forth and back within the cochlea and through the middle ear. This thesis "does windows," addressing wave propagation and scattering on both sides of the middle ear. A summary of highlights follows. Measurements of the cochlear input impedance in cat are used to identify a new symmetry in cochlear mechanics--termed "tapering symmetry" after its geometric interpretation in simple models--that guarantees that the wavelength of the traveling wave changes slowly with position near the stapes. Waves therefore propagate without reflection through the basal turns of the cochlea. Analytic methods for solving the cochlear wave equations using a perturbative scattering series are given and used to demonstrate that, contrary to common belief, conventional cochlear models exhibit negligible internal reflection whether or not they accurately represent the tapering symmetries of the inner ear. Frameworks for the systematic "deconstruction" of eardrum and middle-ear transduction characteristics are developed and applied to the analysis of noninvasive measurements of middle-ear and cochlear mechanics. A simple phenomenological model of inner-ear compressibility that correctly predicts hearing thresholds in patients with missing or disarticulated middle-ear ossicles is developed and used to establish an upper bound on cochlear compressibility several orders of magnitude smaller than that provided by direct measurements. Accurate measurements of stimulus -frequency evoked otoacoustic emissions are performed and used to determine the form and frequency variation of the cochlear traveling-wave ratio noninvasively. Those measurements are inverted to obtain the spatial distribution of mechanical inhomogeneities responsible for evoked emission. Although current models require that the periodicities found in emission spectra and threshold hearing curves originate in a corresponding corrugation in the mechanics of the cochlea, it is shown that the observed spectral periodicities can arise spontaneously through the dynamics of wave propagation and reflection and that the organ of Corti, as suggested by the anatomy, need manifest no particular translational symmetries.

Shera, Christopher Alan

63

Ear localization using hierarchical clustering  

NASA Astrophysics Data System (ADS)

Ear biometrics has been found to be a good and reliable technique for human recognition. With the initial doubts on uniqueness of the ear, ear biometrics could not attract much attention. But after it has been said that it is almost impossible to find two ears with all the parts identical, ear biometrics has gained its pace. To automate the ear based recognition process, ear in the image is required to be localized automatically. This paper presents a technique for the same. Ear localization in the proposed technique is carried out by using the hierarchical clustering of the edges obtained from the side face image. The technique is tested on a database consisting of 500 side face images of human faces collected at IIT Kanpur. It is found to be giving 94.6% accuracy.

Prakash, Surya; Jayaraman, Umarani; Gupta, Phalguni

2009-05-01

64

A facet of ear training  

Microsoft Academic Search

Ear training is a familiar therapeutic concept to speech clinicians working with children having articulation defects. In this article a modified approach to classical ear?training methods is described.

Lon Emerick

1967-01-01

65

Protecting Your Ears  

MedlinePLUS

... your headset If you have a ringing sound in your ears after hearing loud sounds Content last updated July 24, 2013 top Twitter Facebook About this site Mission Statement Privacy Policy For the Media Contact Us This site is owned and maintained ...

66

Ringing in Your Ears?  

MedlinePLUS

... Features Claims About Cocoa Ringing in Your Ears? Wise Choices Links What Causes Tinnitus? Several conditions can lead to tinnitus, including: Noise-induced hearing loss Diseases of the heart or blood vessels Ménière’s disease, a disorder of the inner ...

67

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

68

Mimicking the human ear  

Microsoft Academic Search

A prosthetic device, called a cochlear implant, can be implanted in the inner ear and can restore partial hearing to profoundly deaf people. Some individuals with implants can now communicate without lip-reading or signing, and some can communicate over the telephone. The success of cochlear implants can be attributed to the combined efforts of scientists from various disciplines including bioengineering,

P. C. Loizou

1998-01-01

69

Ear infection - acute  

MedlinePLUS

... Kearney DH, et al. Treatment of acute otitis media in children under 2 years of age. N Engl J ... the development of asymptomatic middle ear effusion in children with acute otitis media: a meta-analysis of individual patient data. Arch ...

70

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

71

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

72

Complications of ear disease.  

PubMed

Forty-seven patients with acute mastoiditis were treated in our hospital over a 2 and a half year period. Seven patients were symptomatic for a short period only. The other 40 gave a history of chronic ear disease, 22 of them with cholesteatoma. Post auricular swelling is an important sign of acute mastoiditis but was found in only 64% of the patients. Forty-five percent of our patients were found to have infection spread beyond the mastoid. Meningitis was the most common complication (13 patients). Most of the patients who presented without post auricular swelling were diagnosed as a result of having one or more complications. We believe that in cases of intracranial pathology or septic fever associated with ear disease, the diagnosis of mastoiditis is most likely. Early operation combined with appropriate antibiotic treatment can prevent further complications and fatal outcome. PMID:3243012

Yaniv, E; Pocock, R

1988-10-01

73

Polyunsaturated fatty acids induce polarized submembranous F-actin aggregates and kill Entamoeba histolytica.  

PubMed

We have recently identified a novel galacto-glycerolipid (GGL) from the plant Oxalis corniculata that killed the human pathogen Entamoeba histolytica. In this study, we show that the anti-amoebic activity of GGL was due to the polyunsaturated fatty acid ?-linolenic acid (C18:3 ) side chain. Treatment of ?-linolenic acid to E. histolytica trophozoites disrupted the cytoskeletal network and led to polarization of F-actin at one end of the cells with prominent filopodial extensions. In addition, clustering of surface receptors and signaling molecules was also observed adjacent to the polarized actin similar to concanavalin-A-(Con-A) induced capping. But, in contrast to Con-A-induced capping, ?-linolenic acid induced caps were not shed and showed accumulation of long and numerous filopodia at the cap site. We found that ?-linolenic acid disrupts the actin cytoskeletal network, which led to the detachment of plasma membrane from the underlying cytoskeleton. A similar effect was observed with other dietary fatty acids such as linoleic acid (C18:2 ), arachidonic acid (C20:4 ), eicosapentaenoic acid (C20:5 ), and docosahexaenoic acid (C22:6 ). Our findings showed that dietary polyunsaturated fatty acids are powerful anti-amoebic agents that lead to disruption of the actin cytoskeleton. PMID:23568815

Manna, Dipak; Grewal, Jaspreet Singh; Sarkar, Bidyut; Maiti, Sudipta; Lohia, Anuradha

2013-04-08

74

Analysis of Arachidonic Acid Metabolites and Platelet Activating Factor Production.  

National Technical Information Service (NTIS)

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. Analysis of these substances in biological tissue...

M. Madden J. Samet H. Koren M. Friedman

1991-01-01

75

Inhibition of arachidonate release from rat peritoneal macrophage by biflavonoids  

Microsoft Academic Search

Biflavonoid is one of unique classes of naturally-occurring bioflavonoid. Previously, certain biflavonoids were found to possess\\u000a the inhibitory effects on phospholipase A2 activity and lymphocytes proliferation1 suggesting their anti-inflammatory\\/immunoregulatory potential. In this study, effects of several biflavonoids on arachidonic\\u000a acid release from rat peritoneal macrophages were investigated, because arachidonic acid released from the activated macrophages\\u000a is one of the indices

Song Jin Lee; Kun Ho Son; Hyeun Wook Chang; Sam Sik Kang; Hyun Pyo Kim

1997-01-01

76

Arachidonic acid cytochrome P450 epoxygenase pathway.  

PubMed

Cytochrome P450 (CYP) epoxygenases convert arachidonic acid to four epoxyeicosatrienoic acid (EET) regioisomers, 5,6-, 8,9-, 11,12-, and 14,15-EET, that function as autacrine and paracrine mediators. EETs produce vascular relaxation by activating smooth muscle large-conductance Ca2+-activated K+ channels (BKCa). In addition, they have anti-inflammatory effects on blood vessels and in the kidney, promote angiogenesis, and protect ischemic myocardium and brain. CYP epoxygenases also convert eicosapentaenoic acid to vasoactive epoxy-derivatives, and endocannabinoids containing 11,12- and 14,15-EET are formed. Many EET actions appear to be initiated by EET binding to a membrane receptor that activates ion channels and intracellular signal transduction pathways. However, EETs also are taken up by cells, are incorporated into phospholipids, and bind to cytosolic proteins and nuclear receptors, suggesting that some functions may occur through direct interaction of the EET with intracellular effector systems. Soluble epoxide hydrolase (sEH) converts EETs to dihydroxyeicosatrienoic acids (DHETs). Because this attenuates many of the functional effects of EETs, sEH inhibition is being evaluated as a mechanism for increasing and prolonging the beneficial actions of EETs. PMID:18952572

Spector, Arthur A

2008-10-23

77

Biochemical and subcellular distribution of arachidonic acid in rat myocardium  

SciTech Connect

Selective release of arachidonic acid from prelabeled phospholipid pools has been observed following exposure of neonatal rat cardiac myocytes to metabolic inhibitors in vitro and has been correlated temporally with the development of irreversible sarcolemmal damage. Hydrolysis of phospholipids with release of arachidonic acid may be an important mechanism in the pathogenesis of sarcolemmal damage induced by ischemia. To elucidate potential subcellular loci of arachidonic acid release in ischemic myocardium, the authors characterized the phospholipid composition of adult rat myocardial sarcolemma and delineated the biochemical and subcellular distribution of radiolabeled arachidonic acid in neonatal rat myocytes incubated with ({sup 3}H)-arachidonic acid for selected intervals. Radioactivity was located almost exclusively in mitochondria and internal cytoplasmic membranes (primarily sarcoplasmic reticulum), which collectively contained 90% of myocyte radioactivity. These results indicate that radiolabeled arachidonic acid released from prelabeled phospholipid pools on exposure of neonatal rat myocytes to oxidative inhibitors is derived from mitochondria and internal cell membranes. The diminutive labeling of the sarcolemma suggests that turnover of arachidonoyl phospholipids is slower in the sarcolemma than in other membranous organelles.

Miyazaki, Y.; Gross, R.W.; Sobel, B.E.; Saffitz, J.E. (Washington Univ., St. Louis, MO (USA))

1987-12-01

78

Sulfuric Acid-Induced Corrosion of Aluminum Surfaces.  

National Technical Information Service (NTIS)

The sulfuric acid-induced corrosion of smooth (2 nm average roughness) aluminum surfaces has been studied in real times using an in situ Fourier transform infrared reflection absorption spectrometer and a quartz crystal microbalance. Submicron thick, 35 t...

Q. Dai A. Freedman G. N. Robinson

1995-01-01

79

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

80

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

81

Bells in Your Ears  

NSDL National Science Digital Library

Does sound travel better through solids or gases? This material is part of a series of hands-on science activities designed to arouse student interest. Here the student hangs a metal fork from a pencil using string, and then strikes the fork while the eraser end of the pencil is in his or her ear. The activity includes a description, a list of science process skills and complex reasoning strategies being used, and a compilation of applicable national science standards for grades K-12. Also provided are content topics, a list of necessary supplies, instructions to perform the activity, and presentation techniques. The activity's content is explained, and assessment suggestions are provided.

Mid-continent Research for Education and Learning (McREL); Jacobs, Steve

2004-01-01

82

Pinna abnormalities and low-set ears  

MedlinePLUS

Low-set ears; Microtia; "Lop" ear ... Abnormal folds or location of the pinna Low-set ears No opening to the ear canal No ... The following common conditions can cause low-set and unusually ... and malformed ears include: Beckwith-Wiedemann syndrome Potter ...

83

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

84

21 CFR 870.2710 - Ear oximeter.  

Code of Federal Regulations, 2013 CFR

... 8 2013-04-01 2013-04-01 false Ear oximeter. 870.2710 Section 870.2710...Cardiovascular Monitoring Devices § 870.2710 Ear oximeter. (a) Identification. An ear oximeter is an extravascular device used...

2013-04-01

85

Ear Infection Treatment: Do Alternative Therapies Work?  

MedlinePLUS

... use only. Ear infection treatment: Do alternative therapies work? By Mayo Clinic staff Original Article: http://www. ... Sign up Ear infection treatment: Do alternative therapies work? Alternative ear infection treatments aren't generally recommended ...

86

How to Use Ear Drops Properly  

MedlinePLUS

How to Use Ear Drops Properly (Having someone else give you the ear drops may make this procedure easier.) 1 Wash your hands ... with soap and water. 2 Gently clean your ear with a damp facecloth and then dry your ...

87

NICKEL CORRECTS MOUSE-EAR.  

Technology Transfer Automated Retrieval System (TEKTRAN)

The mouse-ear disorder of pecan is a long standing problem that has resisted a solution for nearly a 100 years. Information is discussed relating to how mouse-ear is induced and what orchard managers can do to correct the disorder. Orchard management factors such as soil pH, soil moisture, amount ...

88

Middle Ear Mucocele  

PubMed Central

The complications of posterior fossa surgery continue to decrease in incidence as our collective experience broadens. Most complications are seen in the immediate postoperative period and the minimized by careful attentiveness to subtle changes in mental status, vital signs, and cranial nerve examination. Long-term follow-up is necessary to identify tumor recurrence, but strict imaging protocols as yet do not exist to facilitate the early identification of recurrent disease, as recurrence is very rare. We report the first case of secondary mucocele formation in the middle ear cleft following translabyrinthine excision of an intracanalicular acoustic neuroma. This complication was found in the fourth postoperative year on routine magnetic resonance imaging, which itself followed previously normal contrasted magnetic resonance imaging in the second postoperative year. The genesis of this complication and possible treatment options are discussed. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5

Farris, Paul; Brown, Karla; Vuitch, Frank; Meyerhoff, William L.

1997-01-01

89

Pressure difference receiving ears.  

PubMed

Directional sound receivers are useful for locating sound sources, and they can also partly compensate for the signal degradations caused by noise and reverberations. Ears may become inherently directional if sound can reach both surfaces of the eardrum. Attempts to understand the physics of such pressure difference receiving ears have been hampered by lack of suitable experimental methods. In this review, we review the methods for collecting reliable data on the binaural directional cues at the eardrums, on how the eardrum vibrations depend on the direction of sound incidence, and on how sound waves behave in the air spaces leading to the interior surfaces of eardrums. A linear mathematical model with well-defined inputs is used for exploring how the directionality varies with the binaural directional cues and the amplitude and phase gain of the sound pathway to the inner surface of the eardrum. The mere existence of sound transmission to the inner surface does not ensure a useful directional hearing, since a proper amplitude and phase relationship must exist between the sounds acting on the two surfaces of the eardrum. The gain of the sound pathway must match the amplitude and phase of the sounds at the outer surfaces of the eardrums, which are determined by diffraction and by the arrival time of the sound, that is by the size and shape of the animal and by the frequency of sound. Many users of hearing aids do not obtain a satisfactory improvement of their ability to localize sound sources. We suggest that some of the mechanisms of directional hearing evolved in Nature may serve as inspiration for technical improvements. PMID:18364558

Michelsen, Axel; Larsen, Ole Naesbye

2007-12-19

90

Inner and outer ear anatomy  

NSDL National Science Digital Library

Sounds are actually waves from vibrations. The outer ear catches these waves and funnels them down into the inner ear. The waves reach the eardrum and in turn make the eardrum vibrate. Three small bones receive these vibrations next, then a snail shell-shaped structure called the cochlea. The cochlea is filled with liquid, and this liquid stimulates hairs inside the inner ear. The hairs transmit the signal to the auditory nerve where the signal is taken to the brain and processed as sound.

Zina Deretsky (National Science Foundation;)

2006-10-23

91

Valproic acid induces caspase 3-mediated apoptosis in microglial cells  

Microsoft Academic Search

Valproic acid is widely used for the treatment of epilepsy and mood disorders, but its mode of action is unclear. Treatment of neuronal cells with valproic acid promotes neurite sprouting, is neuroprotective and drives neurogenesis; however its effects on non-neuronal brain cells are less clear. We report that valproic acid induces apoptosis in the mouse microglial cell line, BV-2, at

M. Dragunow; J. M. Greenwood; R. E. Cameron; P. J. Narayan; S. J. O’Carroll; A. G. Pearson; H. M. Gibbons

2006-01-01

92

Docosahexaenoic acid and arachidonic acid in infant development  

Microsoft Academic Search

Docosahaxaenoic acid and arachidonic acid are highly concentrated in the central nervous system. The amount of these fatty acids in the central nervous system increases dramatically during the last intrauterine trimester and the first year of life. A central question of research conducted during the past 20 years is if the essential fatty acid precursor of docosahexaenoic acid is sufficient

Susan E. Carlson

2001-01-01

93

Apoptosis in human primary brain tumours: actions of arachidonic acid  

Microsoft Academic Search

It has been postulated that loss of proliferative control in tumour cells is a consequence of depletion of cellular arachidonic acid (AA) and that exogenous AA and n-6 fatty acids may restore control of proliferation. To test this hypothesis and to investigate the activity of AA, apoptosis in human primary brain tumour cells was analysed using flow terminal deoxynucleotide transferase

J. R. Williams; H. A. Leaver; J. W. Ironside; E. P. Miller; I. R. Whittle; A. Gregor

1998-01-01

94

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

95

Ear identification: a pilot study.  

PubMed

Although several papers have recently been devoted to establishing the validity of identification using the ear, this part of the human body still remains underexploited in forensic science. The perfect overlap of two images of the same ear is not really possible, but photographs of the ears as a reliable means of inferring the identity of an individual are poorly treated in the literature. In this study, we illustrate a simple, reproducible method, which divides the photograph of an ear into four parts-helix, antihelix, concha, and lobe-by means of a suitable grid of four straight lines. Although the division does not follow exact anatomical features, their edges do join anatomical points which are more easily identifiable. Measurement of certain areas of these parts can be combined to produce a code allowing personal identification. This method produces false-positive identifications of <0.2%. Last, the repeatability and reproducibility aspects of the method are tested. PMID:21729082

Cameriere, Roberto; DeAngelis, Danilo; Ferrante, Luigi

2011-04-19

96

Avoiding Infection After Ear Piercing  

MedlinePLUS

... for Families (PedFACTs) Home Strength Training for Young Athletes HealthyChildren.org Post-it Notes Pediatric First Aid for Caregivers ... Chronic Conditions Developmental Disabilities Ear Nose & Throat Emotional ...

97

[Viral infection and ear diseases].  

PubMed

The association of viral infection to ear disease has triggered a great deal of interests. In the present paper, we provide a critical review of the viral hypothesis of ear diseases. Detection of viral antigen and antibody or RNA and DNA in the patients serum, endolymphatic fluid or surgical pathology specimens reveals that virus may have relevance to certain kinds of ear diseases, such as Meniere's disease, idiopathic sudden sensorineural hearing loss, otosclerosis. Bell's palsy and otitis media. The most appealing is the herpesvirus, which can cause latent infection in the neurons, and its reactivation may be the mechanism of recurrent attacks of ear diseases. Currently, antiviral drug treatment plus supportive therapy are the most effective managements dealing with viral infection. Although antiviral vaccine will become a promising preventive strategy in the future. PMID:23937021

Liu, Yuehang; Wang, Zhengmin

2013-05-01

98

Middle ear effusion: current concepts.  

PubMed

Middle ear fluid is a common problem in children. Eustachian tube dysfunction has been considered the key to the pathogenesis of this disorder, but new studies show that other factors may be operative. Inflammation appears to play a significant role in high-viscosity effusion, and these effusions may be related to acute suppurative otitis media. Since persistent mild hearing loss may adversely affect verbal development, new emphasis on early treatment of middle ear effusion is warranted. PMID:645530

McCurdy, J A

1978-04-01

99

Acid-Induced Equilibrium Folding Intermediate of Human Platelet Profilin †  

Microsoft Academic Search

The acid-induced unfolding of human platelet profilin (HPP) can be minimally modeled as a three-state process. Equilibrium unfolding studies have been performed on human platelet profilin1 (HPP) and monitored by far-UV circular dichroism, tryptophan fluorescence, ANS binding, and NMR spectroscopy. Far-UV CD measurements obtained by acid titration demonstrate that HPP unfolds via a three-state mechanism (N f I f U),

Glendon D. McLachlan; Sean M. Cahill; Mark E. Girvin; Steven C. Almo

2007-01-01

100

Influence on the ear-to-ear link loss from heterogeneous head phantom variations  

Microsoft Academic Search

We have investigated the detuning of the antennas and the ear-to-ear link loss for the in-the-ear (ITE) binaural hearing aids considering the different heterogeneous human phantoms through FDTD simulations. It was found that the resonance frequency shifts differently for different phantoms and between the ears within the same phantom. The ear-to-ear link loss between the antennas for the homogeneous SAM

Rohit Chandra; Anders J Johansson

2011-01-01

101

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

102

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

103

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

104

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

105

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

106

Arachidonic acid assimilation by thrombocytes from white carneau pigeons  

SciTech Connect

The metabolism of arachidonic acid was investigated using thrombocyte-enriched-plasma from RBWC and WC-II white carneau pigeons, which differ genetically in their susceptibility to atherosclerosis. Thrombocytes were incubated at 42 C with (/sup 14/C) arachidonate in Puck's solution. After a 1 hour labeling period the WC-II cells had taken up 69% and RBWC 77% of the (/sup 14/C)arachidonate from the medium. When 8,11,14-eicosatrienoic acid or 5,8,11,14,17-eicosapentaenoic acid were added to incubation media the (/sup 14/C) uptake was reduced in each type cell, with WC-II exhibiting the greatest effect. Release of (/sup 14/C)molecules from cells labeled with (/sup 14/)Carachidonate was studied using calcium ionophore and indomethacin. Indomethacin inhibited (/sup 14/C) molecule release similarly in both RBWC and WC-II cells. Calcium ionophore was twice as effective in stimulating (/sup 14/C)molecule release from WC-II than RBWC cells. Therefore, the WE-II cells (from pigeons greater in susceptibility to atherosclerosis) are more sensitive to calcium ionophore than the REWC cells.

Saxon, D.J.; Blankenship, T.

1986-03-01

107

Local Inner Ear Drug Delivery and Pharmacokinetics  

PubMed Central

Summary A number of drugs are in widespread clinical use for the treatment of inner ear disorders by applying them directly to the inner ear. Many new substances and drug delivery systems specific to the inner ear are under development, and in some cases are undergoing evaluations in animal experiments and in clinical studies. The pharmacokinetics of drugs in the inner ear, however, is not well defined and the field is plagued by technical problems in obtaining pure samples of the inner ear fluids for analysis. Nevertheless, a basic understanding of the mechanisms of drug dispersal in the inner ear has emerged that facilitates the design and interpretation of future pharmacokinetic studies.

Salt, Alec N.; Plontke, Stefan K.R.

2008-01-01

108

Anti-inflammatory properties of the protein kinase C inhibitor, 3-[1-[3-(dimethylamino)propyl]-1H-indol-3-yl]-4(1H-indol-3-yl)-1H-pyrrole-2,5-dione monohydrochloride (GF109203X) in the PMA-mouse ear edema model  

Microsoft Academic Search

Protein kinase C (PKC) mediates a number of intracellular signal transduction pathways implicated in the pathogenesis of inflammation, including phospholipase A2-dependent arachidonic acid release and eicosanoid production. Recent studies demonstrate that the PKC inhibitor GF109203X significantly reduces a number of inflammatory processes resulting from PKC activation by the topical application of phorbol myristate acetate (PMA) to mouse ears. In this

S. Kuchera; H. Barth; P. Jacobson; A. Metz; C. Schaechtele; D. Schrier

1993-01-01

109

Within-ear and across-ear interference in a cocktail-party listening task  

NASA Astrophysics Data System (ADS)

Although many researchers have shown that listeners are able to selectively attend to a target speech signal when a masking talker is present in the same ear as the target speech or when a masking talker is present in a different ear than the target speech, little is known about selective auditory attention in tasks with a target talker in one ear and independent masking talkers in both ears at the same time. In this series of experiments, listeners were asked to respond to a target speech signal spoken by one of two competing talkers in their right (target) ear while ignoring a simultaneous masking sound in their left (unattended) ear. When the masking sound in the unattended ear was noise, listeners were able to segregate the competing talkers in the target ear nearly as well as they could with no sound in the unattended ear. When the masking sound in the unattended ear was speech, however, speech segregation in the target ear was substantially worse than with no sound in the unattended ear. When the masking sound in the unattended ear was time-reversed speech, speech segregation was degraded only when the target speech was presented at a lower level than the masking speech in the target ear. These results show that within-ear and across-ear speech segregation are closely related processes that cannot be performed simultaneously when the interfering sound in the unattended ear is qualitatively similar to speech.

Brungart, Douglas S.; Simpson, Brian D.

2002-12-01

110

Earedness: Left-eared and right-eared listeners  

Microsoft Academic Search

The Huggins pitch (HP) stimulus known as HP- is created with a broadband background noise having an interaural phase difference of zero, together with a narrow boundary region wherein the interaural phase varies with frequency. At the spectral center of the boundary region the interaural phase is 180 deg. Therefore, HP- is symmetrical with respect to the two ears. Despite

William M. Hartmann; Peter Xinya Zhang; John F. Culling

2001-01-01

111

Inner ear drug delivery for auditory applications.  

PubMed

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. PMID:18848590

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

2008-09-21

112

Foreign Object in the Ear: First Aid  

MedlinePLUS

Foreign object in the ear: First aid Basics Resources Reprints A single copy of this article may be reprinted for personal, noncommercial use only. Foreign object in the ear: First aid By Mayo Clinic staff Original Article: ...

113

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...

2013-04-01

114

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

115

Dynamic study of the middle ear  

Microsoft Academic Search

The human ear is a complex biomechanical system and is divided by three parts: outer, middle and inner ear.\\u000a \\u000a When a sound is made outside the outer ear, the sound waves travel down the external auditory canal and strike the eardrum.\\u000a It vibrates and the vibrations pass through three tiny bones in the middle ear called the ossicles (malleus, incus

F Gentil; R M Natal Jorge; A J M Ferreira; M P L Parente; M Moreira; E Almeida

116

Total alloplastic middle ear implant.  

PubMed

A total alloplastic middle ear prosthesis (TAM), composed of a spongy substance consisting of Teflon and pyrolytic graphite is presented. This prosthesis allows a safe eradication of the diseased tissue and approximates a physiological reconstruction of the sound conducting system. The results obtained in three patients with this TAM up to an observation period of more than two years are promising. PMID:7406761

Grote, J J; Kuijpers, W

1980-09-01

117

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

118

Frog eye, ear, and nostril  

NSDL National Science Digital Library

You can clearly see the frog's eye. There is an air opening near a black spot on the frog's skin. The opening to the frog's ear is covered by the round, tan membrane to the left in the picture. This membrane is called the tympanum.

Ren West (None;)

2006-08-07

119

Tympanoplasty on only hearing ears.  

PubMed

The methods, results, and indications for operation on only hearing ears are discussed on the basis of 13 patients operated upon for chronic otitis media and its sequelae. Although good results were obtained, with an air-bone gas closure within 15 dB. in 77 per cent, this should not serve as propaganda for the general use of surgery on only hearing ears. On the other hand, they show that surgery on only hearing ears should not be rejected a priori and that on certain indications and under c ertain circumstanc es it may be carried out with minimal risk of aggravating the hearing loss. In most of the patients the indication for surgery was a progressing cholesteatoma, in some cases the sequelae of otitis, either in the form of myringoplasty or type II tympanoplasty, and one patient had the operation on a vital indication. To avoid postoperative exacerbation of the hearing, the patients must be strictly selected, the ears have to be pretreated conservatively, the Eustachian tube must be passable, the operation must be carried out by the most experienced otosurgeon, and thoroughly tested, very gentle operative methods must be used. PMID:1202116

Tos, M; Falbe Hansen, J

1975-10-01

120

Valproic acid-induced hyperammonaemic coma and unrecognised portosystemic shunt.  

PubMed

Hyperammonaemic encephalopathy is a rare and potentially fatal complication of valproic acid treatment. The clinical presentation of hyperammonaemic encephalopathy is wide and includes seizures and coma. We present a case of hyperammonaemic coma precipitated by sodium valproate use for symptomatic epilepsy in a patient with unrecognised portosystemic shunt, secondary to earlier alcoholism. The absence of any stigmata of chronic liver disease and laboratory markers of liver dysfunction delayed the recognition of this alcohol-related complication. The portal vein bypass led to a refractory, valproic acid-induced hyperammonaemic coma. The patient fully recovered after dialysis treatment. PMID:23774155

Nzwalo, Hipólito; Carrapatoso, Leonor; Ferreira, Fátima; Basilio, Carlos

2013-06-01

121

Antithetic relationship of dietary arachidonic acid and eicosapentaenoic acid on eicosanoid production in vivo  

Microsoft Academic Search

Eicosanoids are oxidative derivatives of arachidonic acid. When produced in excessive amounts, many are pro- inflammatory and\\/or prothrombotic agents. N-3 polyunsatu- rated fatty acids (PUFA) have been used to attenuate tissue arachidonic acid (AA, 20:4 n-6) levels and thus modulate eicosa- noid production. However, there is growing evidence that dietary arachidonic acid may also be able to modulate eicosa- noid

Bangyan Li; Christopher Birdwell; Jay Whelan

122

A Simple Geometric Approach for Ear Recognition  

Microsoft Academic Search

With the increase in need for strong security systems, the biometric systems are becoming more and more popular. These systems are based on human traits which, unlike passwords or pins, cannot be lost, stolen or forgotten. One such trait is ear. With the initial doubts on uniqueness of ear, ear biometrics could not attract much attention. But after it has

Dasari Shailaja; Phalguni Gupta

2006-01-01

123

STRUCTURE AND FUNCTION IN WHALE EARS  

Microsoft Academic Search

Ultrasonic echolocation abilities are well documented in several dolphin species, but hearing characteristics are unknown for most whales. Vocalization data suggest whale hearing spans infra- to ultrasonic ranges. This paper presents an overview of whale ear anatomy and analyzes 1) how whale ears are adapted for underwater hearing and 2) how inner ear differences relate to different hearing capacities among

DARLENE R. KETTEN

1997-01-01

124

Handedness and Preferred Ear for Telephoning.  

ERIC Educational Resources Information Center

Examined relationship between handedness and preferred ear for telephoning in 140 college students. Increased degree of sinistrality was associated with increased tendency to use left ear for telephoning. Found tendency to pick up telephone receiver with preferred hand and hold earpiece to ipsilateral ear. Results may relate to reports of reduced…

Williams, Stephen M.

1987-01-01

125

Attenuation of acid induced oesophagitis in VR-1 deficient mice  

PubMed Central

Background and aims Activation of the vanilloid receptor subtype 1 (VR?1) results in release of proinflammatory peptides which initiate an inflammatory cascade known as neurogenic inflammation. We investigated its role in an acute model of surgically induced oesophagitis. Methods Oesophagitis was induced by pyloric ligation in wild?type and VR?1 deficient mice. A subset of animals were administered the VR?1 antagonist capsazepine, famotidine, or omeprazole one hour before surgery. Five hours after surgery, myeloperoxidase activity (MPO), histological damage scores, intragastric pH, and immunocytochemical analysis of substance P (SP) receptor endocytosis were determined. Results Oesophagitis induced knockout mice exhibited significantly lower levels of MPO activity, histological damage scores, and SP receptor endocytosis than wild?type mice. Inflammatory parameters were significantly reduced by acid inhibition and capsazepine in wild?type mice. Conclusions We conclude that acute acid induced oesophagitis is reduced in animals lacking VR?1. This suggests that acid induced oesophagitis may act through VR?1 and that inhibition of the receptor may reduce inflammation.

Fujino, K; de la Fuente, S G; Takami, Y; Takahashi, T; Mantyh, C R

2006-01-01

126

Autogenous and prosthetic reconstruction of the ear.  

PubMed

Injuries to the ear can result in partial or complete loss of the external ear. Resection of the external ear may be necessary secondary to malignant tumor or infection. This article discusses the diagnosis and management of acquired defects of the external ear. Because autogenous reconstruction is not always possible, both autogenous and prosthetic reconstruction are presented as well as the indications for both. This information should help guide the clinician in the decision-making process. In the hands of experienced clinicians, reconstruction of the external ear can result in an excellent outcome, with improved quality of life for the patient. PMID:23522966

Louis, Patrick J; Aponte-Wesson, Ruth A; Fernandes, Rui P; Clemow, Justin

2013-03-21

127

Fungal arachidonic acid-rich oil: research, development and industrialization.  

PubMed

Abstract Fungal arachidonic acid (ARA)-rich oil is an important microbial oil that affects diverse physiological processes that impact normal health and chronic disease. In this article, the historic developments and technological achievements in fungal ARA-rich oil production in the past several years are reviewed. The biochemistry of ARA, ARA-rich oil synthesis and the accumulation mechanism are first introduced. Subsequently, the fermentation and downstream technologies are summarized. Furthermore, progress in the industrial production of ARA-rich oil is discussed. Finally, guidelines for future studies of fungal ARA-rich oil production are proposed in light of the current progress, challenges and trends in the field. PMID:23631634

Ji, Xiao-Jun; Ren, Lu-Jing; Nie, Zhi-Kui; Huang, He; Ouyang, Ping-Kai

2013-04-30

128

Effects of naturally occurring dihydroflavonols from Inula viscosa on inflammation and enzymes involved in the arachidonic acid metabolism.  

PubMed

The anti-inflammatory properties of three flavanones isolated from Inula viscosa, sakuranetin, 7-O-methylaromadendrin, and 3-acetyl-7-O-methylaromadendrin, have been tested both in vitro and in vivo. Acute inflammation in vivo was induced by means of topical application of 12-O-tetradecanoylphorbol 13-acetate (TPA) to mouse ears or by subcutaneous injection of phospholipase A(2) (PLA(2)) into mouse paws. The test compounds were evaluated in vitro for their effect on both the metabolism of arachidonic acid and on the release and/or activity of enzymes involved in the inflammatory response such as elastase, myeloperoxidase (MPO), and protein kinase C (PKC). The most active compounds in vivo against PLA(2)-induced paw oedema were 7-O-methylaromadendrin (ED(50)=8 mg/kg) and sakuranetin (ED(50)=18 mg/kg). In contrast, the most potent compound against TPA-induced ear oedema was 3-acetyl-7-O-methylaromadendrin (ED(50)=185 microg/ear), followed by sakuranetin (ED(50)=205 microg/ear). In vitro, the latter compound was the most potent inhibitor of leukotriene (LT) B(4) production by peritoneal rat neutrophils (IC(50)=9 microM) and it was also the only compound that directly inhibited the activity of 5-lipoxygenase (5-LOX). 3-Acetyl-7-O-methylaromadendrin also inhibited LTB(4) production (IC(50)=15 microM), but had no effect on 5-LOX activity. The only flavanone that inhibited the secretory PLA(2) activity in vitro was 7-O-methylaromadendrin. This finding may partly explain the anti-inflammatory effect observed in vivo, although other mechanisms such as the inhibition of histamine release by mast cells may also be implicated. Sakuranetin at 100 microM was found to inhibit elastase release, although this result is partly due to direct inhibition of the enzyme itself. At the same concentration, 7-O-methylaromadendrin only affected the enzyme release. Finally, none of the flavanones exhibited any effect on MPO or PKC activities. Taken together, these findings indicate that sakuranetin may be a selective inhibitor of 5-LOX. PMID:17658557

Hernández, Victoriano; Recio, M Carmen; Máñez, Salvador; Giner, Rosa M; Ríos, José-Luis

2007-06-28

129

Biophysics of the ensiferan ear  

Microsoft Academic Search

1.The small (anterior) tympanal membrane in the ear of the cricketGryllus campestris L. is non-functional in hearing (Fig. 4).2.The large (posterior) tympanum vibrates in its basic mode in the entire frequency range investigated (1–30 kHz).3.The velocity and the phase angle (sound pressure to vibration velocity) of the large tympanum are very much influenced by whether the ipsilateral spiracle is open

Ole N. Larsen; Axel Michelsen

1978-01-01

130

Modulation of arachidonic acid metabolism by bovine alveolar macrophages  

SciTech Connect

The purpose of this study were to identify the arachidonic acid (AA) metabolites produced by cultured bovine alveolar macrophages (AM), to investigate the effects of various stimuli on the production of those metabolites, and to study the effect of interferons and lipopolysaccharide on AA metabolism by AM. Initial studies were conducted to ascertain which AA metabolites are produced by bovine alveolar macrophages. Cultured macrophages were labeled with tritiated arachidonic acid and stimulated with calcium ionophore A23187. The radiolabeled AA metabolites released were identified using reverse-phase high-performance liquid chromatography. The production of LTB{sub 4}, TXB{sub 2}, and PGF{sub 2{alpha}} by AM stimulated with A23187 or opsonized zymosan (OPZ) was measured using radioimmunoassay. Finally, the effects of recombinant bovine interferon alpha{sub 1}-1 (IFN-{alpha}{sub 1}-1), recombinant bovine interferon gamma (IFN-{gamma}), and lipopolysaccharide (LPS) derived from Escherichia coli 0111:B4 on the AA metabolism of bovine AM were investigated. These studies indicate that appropriately stimulated bovine AM are the source of a number of AA metabolites. Furthermore, the production of these metabolites may be dramatically altered by exposure of the AM to IFNs or LPS. Such exposure could occur in vivo during gram negative bacterial pneumonias following viral infections. Because AA metabolites are intimately involved in the inflammatory process, it is possible that AM may contribute to the development of pulmonary inflammation in certain situations.

O'Sullivan, M.G.

1989-01-01

131

Dynamic Simulations on the Arachidonic Acid Metabolic Network  

PubMed Central

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 cyclooxygenase-2 (COX-2), have been used as targets for anti-inflammatory drugs. However, neither the century-old nonsteriodal anti-inflammatory drugs nor the recently revocatory Vioxx have provided completely successful anti-inflammatory treatment. To gain more insights into the anti-inflammatory drug design, the authors have studied the dynamic properties of arachidonic acid (AA) metabolic network in human polymorphous leukocytes. Metabolic flux, exogenous AA effects, and drug efficacy have been analyzed using ordinary differential equations. The flux balance in the AA network was found to be important for efficient and safe drug design. When only the 5-lipoxygenase (5-LOX) inhibitor was used, the flux of the COX-2 pathway was increased significantly, showing that a single functional inhibitor cannot effectively control the production of inflammatory mediators. When both COX-2 and 5-LOX were blocked, the production of inflammatory mediators could be completely shut off. The authors have also investigated the differences between a dual-functional COX-2 and 5-LOX inhibitor and a mixture of these two types of inhibitors. Their work provides an example for the integration of systems biology and drug discovery.

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

2007-01-01

132

Effects of lysophosphatidylcholine and arachidonic acid on the regulation of intracellular Ca 2+ transport  

Microsoft Academic Search

The role of lysophosphatidylcholine and arachidonic acid in signal transduction was investigated using subcellular organelles and permeabilized cells from liver. Both substances can be generated intracellularly by the action of phospholipase A2 on phosphatidy1choline. Lysophosphatidylcholine as well as arachidonic acid raised the free Ca2+ concentration in the incubation media of permeabilized cells, isolated mitochondria and microsomes. The half maximally effective

I. Rustenbeck; S. Lenzen

1989-01-01

133

[Changes, induced by certain flavonoids, of the hypotensive effects of arachidonic acid].  

PubMed

In the rat, silybine and Z 12007, a derivative of rutoside, increase the vasodepressive activities of arachidonic acid, a prostaglandin precursor. They reduce the activity of PGE2. Quercetine also increases the hypotensive action of arachidonic acid. These three flavonoids are supposed to increase the prostaglandin biosynthesis. PMID:143326

Damas, J; Mousty, J C; Lecomte, J

1977-01-01

134

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

135

Stimulation of arachidonic acid mobilization by adherence of resident peritoneal macrophages to plastic substrate  

Microsoft Academic Search

To interpret results of studies on arachidonic acid (AA) mobilization and metabolism in vitro, it is essential that the influence of culture and conditions should be well defined. Thus, we investigated the effects of murine resident peritoneal macrophage adherence and the presence of foetal calf serum in culture medium on arachidonic acid mobilization. The present data demonstrate that [3H] AA

S. Lloret; J. J. Moreno

1996-01-01

136

Arachidonic acid and arachidonoyldiglycerols increase in rat cerebrum during bicuculline-induced status epilepticus  

Microsoft Academic Search

Bicuculline-induced status epilepticus was found to be associated with increased amounts offree fatty acids and diacylglycerols in the rat cerebrum. The predominant fatty acid in both lipid pools was arachidonic acid. The accumulation of arachidonoyl-diglycerols decreased at the time of and during behavioral seizures induced by bicuculline, while the amount of free arachidonic acid appeared to increase. We propose a

Nicolas G. Bazan; Susana A. Morelli de Liberti; Elena B. Rodriguez de Turco

1982-01-01

137

Ferrous iron mediated oxidation of arachidonic acid: studies employing nitroblue tetrazolium (NBT).  

PubMed

The oxidation of arachidonic acid by ferrous sulfate provides a useful model to study the role of iron in lipid oxidation reactions. We have employed nitroblue tetrazolium (NBT) in the present investigation to evaluate the mechanism of this reaction. In the presence of arachidonic acid, Fe +++, and O2, the yellow dye NBT was rapidly reduced to the blue form, NBTH2. The molar ratio of arachidonic acid to Fe++ in this rapid reaction was 1:1, showing an interaction of one fatty acid molecule per iron molecule. Approximately one molecule of NBT was reduced per four molecules of arachidonic acid and Fe++. Reduction of NBT was accompanied by oxidation of Fe++ to Fe+++, suggesting the transfer of four electrons from the Fe++ to NBT to reduce the dye. Arachidonic acid was found to be unchanged when extracted at the end of the reaction, indicating formation of a complex that could dissociate leaving intact arachidonic acid. Evidence for the presence of such a complex which slowly dissociates during the reaction was obtained after longer incubations with small amounts of arachidonic acid. NBT reduction was not inhibited by agents which hydrolyze superoxide, by catalase or by agents which trap hydroxy radicals. We, therefore, propose a model in which NBT traps a radical generated on the arachidonic acid molecule. The proposed model suggests mechanisms for other fatty acid oxidation reactions such as prostaglandin and hydroperoxy fatty acid synthesis. PMID:715068

Peterson, D A; Gerrard, J M; Rao, G H; Krick, T P; White, J G

1978-10-01

138

Effects of Arachidonic Acid on the Lysosomal Ion Permeability and Osmotic Stability  

Microsoft Academic Search

In this study, we investigated the effects of arachidonic acid, a PLA2-produced lipid metabolite, on the lysosomal permeability, osmotic sensitivity and stability. Through the measurements of lysosomal ?-hexosaminidase free activity, membrane potential, intralysosomal pH, and lysosomal latency loss in hypotonic sucrose medium, we established that arachidonic acid could increase the lysosomal permeability to both potassium ions and protons, and enhance

Gu Zhang; Ya-Ping Yi; Guo-Jiang Zhang

2006-01-01

139

Ear canal dynamic motion as a source of power for in-ear devices  

NASA Astrophysics Data System (ADS)

Ear canal deformation caused by temporomandibular joint (jaw joint) activity, also known as ``ear canal dynamic motion,'' is introduced in this paper as a candidate source of power to possibly recharge hearing aid batteries. The geometrical deformation of the ear canal is quantified in 3D by laser scanning of different custom ear moulds. An experimental setup is proposed to measure the amount of power potentially available from this source. The results show that 9 mW of power is available from a 15 mm3 dynamic change in the ear canal volume. Finally, the dynamic motion and power capability of the ear canal are investigated in a group of 12 subjects.

Delnavaz, Aidin; Voix, Jérémie

2013-02-01

140

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

141

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

142

Evidence supporting a correlation between arachidonic acid release and prolactin secretion from GH3 cells.  

PubMed

In this study, pharmacological agents that alter phospholipase A2 activity were examined for their effects on PRL release and arachidonic acid mobilization in GH3 cells, a pituitary tumor cell line. Stimulators of phospholipase A2 activity, melittin and mastoparan, increased PRL release during short term incubation. This stimulation was reduced by carbachol, a cholinergic receptor ligand that inhibits PRL release from GH3 cells. Melittin also caused release of [3H]arachidonic acid that had previously been incorporated into phospholipids. Increased levels of free [3H]arachidonic acid in the medium were associated with a loss of radiolabel from the phospholipid fraction of the cells. The [3H]arachidonic acid in phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol was reduced during melittin exposure. In contrast, two inhibitors of phospholipase A2, dibromoacetophenone (BAP) and U10029A, inhibited spontaneous PRL release. BAP also decreased basal release of [3H]arachidonic acid, blocked melitin-induced PRL secretion, and inhibited melittin-induced [3H] arachidonic acid release. Exogenous arachidonic acid at doses from 10 nM to 1 microM stimulated PRL secretion. The phospholipase A2 inhibitor BAP blocked TRH- and vasoactive intestinal peptide-induced PRL release, whereas U10029A blocked cAMP-induced and blunted TRH- and vasoactive intestinal peptide-induced PRL release. The hydrolysis of membrane phospholipids generating free arachidonic acid and lysophospholipid under our experimental conditions correlated with PRL secretion in GH3 cells. Addition of arachidonic acid to the culture medium stimulated PRL secretion. These data suggest that release of arachidonic acid and its subsequent actions may participate in the intracellular regulation of PRL secretion. PMID:3918856

Camoratto, A M; Grandison, L

1985-04-01

143

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

144

Cytochrome p450 epoxygenase metabolism of arachidonic acid inhibits apoptosis.  

PubMed

The ubiquitous cytochrome P450 hemoproteins play important functional roles in the metabolism and detoxification of foreign chemicals. However, other than established roles in cholesterol catabolism and steroid hormone biosynthesis, their cellular and/or organ physiological functions remain to be fully characterized. Here we show that the cytochrome P450 epoxygenase arachidonic acid metabolite 14,15-epoxyeicosatrienoic acid (14,15-EET) inhibits apoptosis induced by serum withdrawal, H(2)O(2), etoposide, or excess free arachidonic acid (AA), as determined by DNA laddering, Hoechst staining, and fluorescein isothiocyanate-labeled annexin V binding. In the stable transfectants (BM3 cells) expressing a mutant bacterial P450 AA epoxygenase, F87V BM3, which was genetically engineered to metabolize arachidonic acid only to 14,15-EET, AA did not induce apoptosis and protected against agonist-induced apoptosis. Ceramide assays demonstrated increased AA-induced ceramide production within 1 h and elevated ceramide levels for up to 48 h, the longest time tested, in empty-vector-transfected cells (Vector cells) but not in BM3 cells. Inhibition of cytochrome P450 activity by 17-octadecynoic acid restored AA-induced ceramide production in BM3 cells. Exogenous C2-ceramide markedly increased apoptosis in quiescent Vector cells as well as BM3 cells, and apoptosis was prevented by pretreatment of Vector cells with exogenous 14,15-EET and by pretreatment of BM3 cells with AA. The ceramide synthase inhibitor fumonisin B1 did not affect AA-induced ceramide production and apoptosis; in contrast, these effects of AA were blocked by the neutral sphingomyelinase inhibitor scyphostatin. The pan-caspase inhibitor Z-VAD-fmk had no effect on AA-induced ceramide generation but abolished AA-induced apoptosis. The antiapoptotic effects of 14,15-EET were blocked by two mechanistically and structurally distinct phosphatidylinositol-3 (PI-3) kinase inhibitors, wortmannin and LY294002, but not by the specific mitogen-activated protein kinase kinase inhibitor PD98059. Immunoprecipitation followed by an in vitro kinase assay revealed activation of Akt kinase within 10 min after 14,15-EET addition, which was completely abolished by either wortmannin or LY294002 pretreatment. In summary, the present studies demonstrated that 14,15-EET inhibits apoptosis by activation of a PI-3 kinase-Akt signaling pathway. Furthermore, cytochrome P450 epoxygenase promotes cell survival both by production of 14,15-EET and by metabolism of unesterified AA, thereby preventing activation of the neutral sphingomyelinase pathway and proapoptotic ceramide formation. PMID:11509673

Chen, J K; Capdevila, J; Harris, R C

2001-09-01

145

Tamoxifen stimulates arachidonic acid release from rat liver cells by an estrogen receptor-independent, non-genomic mechanism  

Microsoft Academic Search

BACKGROUND: Tamoxifen is widely prescribed for the treatment of breast cancer. Its success has been attributed to the modulation of the estrogen receptor. I have previously proposed that the release of arachidonic acid from cells may also mediate cancer prevention. METHODS: Rat liver cells were radiolabelled with arachidonic acid. The release of [3H] arachidonic acid after various times of incubation

Lawrence Levine

2003-01-01

146

Endoscopic Anatomy of the Middle Ear  

Microsoft Academic Search

Good knowledge of anatomy is fundamental for every surgeon. Middle ear anatomy is really complex and sometimes is challenging\\u000a for otologists, who need to explore every single compartment for a radical removal of pathology. With introduction of the\\u000a endoscope in middle ear surgery, anatomy of middle ear spaces has become wider and clearer due to a better magnification and\\u000a to

Daniele Marchioni; Gabriele Molteni; Livio Presutti

2011-01-01

147

Virtual endoscopy of the middle ear  

Microsoft Academic Search

Virtual endoscopy is a computer-generated simulation of fiberoptic endoscopy, and its application to the study of the middle\\u000a ear has been recently proposed. The need to represent the middle ear anatomy by means of virtual endoscopy arose from the\\u000a increased interest of otolarygologists in transtympanic endoscopy. In fact, this imaging method allows the visualization of\\u000a middle ear anatomy with high

E. Neri; D. Caramella; M. Panconi; S. Berrettini; S. Sellari Franceschini; F. Forli; C. Bartolozzi

2001-01-01

148

Using Ear Biometrics for Personal Recognition  

Microsoft Academic Search

\\u000a Application and research of ear recognition technology is a new subject in the field of biometrics recognition. Earlier research\\u000a showed that human ear is one of the representative human biometrics with uniqueness and stability. Feasibility and characteristics\\u000a of ear recognition was discussed and recent advances in 2D and 3D domain was presented. Furthermore, a proposal for future\\u000a research topics was

Li Yuan; Zhichun Mu; Zhengguang Xu

2005-01-01

149

Arachidonic acid deficiency in streptozotocin-induced diabetes.  

PubMed Central

Fatty acid compositions of phospholipids of heart, liver, kidney, aorta, and serum from rats having streptozotocin-induced diabetes were determined and compared with those of nondiabetic controls. Linoleic and dihomo-gamma-linolenic acids were increased whereas arachidonic acid was decreased in most tissues, suggesting an impairment of delta 5-desaturase activity. Acids derived from linolenic acid were increased in some diabetic tissues from diabetic animals although the linolenic content was normal, indicating less impairment in the desaturation of the omega 3 series of fatty acids. Diabetes suppressed all polyunsaturated acids in the whole animal, but the competition between omega 3 and omega 6 acids favored the excessive suppression of long-chain omega 6 acids and an increase in the proportion of omega 3 acids in lipids of vital tissues. These changes in fatty acid composition of the phospholipids may have significant effects on cellular functions and vasoregulatory control mechanisms in diabetes. Images

Holman, R T; Johnson, S B; Gerrard, J M; Mauer, S M; Kupcho-Sandberg, S; Brown, D M

1983-01-01

150

Protein isolation from ear wax made easy.  

PubMed

Cerumen is a waxy substance with a mixture of different lipids and and not yet identified proteins. Analysing ear wax can be quite laborious because of the different and sometimes interfering components. Therefore, time-consuming techniques such as chromatography or spectrometry were used to gain informations about the components of ear wax. Conclusions were drawn from immunohistochemical detections of special proteins within the skin or the glands of the external ear canal about the existence of these proteins within the ear wax. But directly analysing the proteins within the ear wax was difficult. We, therefore, worked out a method to isolate proteins from ear wax. Ear wax was collected from 16 adults with no infections of the external ear canal. The protein isolation was conducted using the Qproteome Mammalian Protein Prep Kit by Qiagen in two different kind of ways (cell and lysat fraction). Afterwards, we performed a quantification of the total protein concentration using the BCA method. There was a statistical significant difference in the total protein concentration between the two different (cell and lysat fraction) described ways. Furthermore, it is a fast and easy method to extract proteins from ear wax. The benefit of the described method and the field of application will be discussed. PMID:19347346

Schwaab, Matthias; Hansen, Stefan; Gurr, Andre; Schwaab, Thomas; Minovi, Amir; Sudhoff, Holger; Dazert, Stefan

2009-04-04

151

Otitis media and ear tubes.  

PubMed

The placement of myringotomy tubes remains an effective treatment of recurrent acute otitis media and chronic otitis media with effusion. Infants and young children are prone to these entities because of their immature anatomy and immunology. Several host, pathogenic, and environmental factors contribute to the development of these conditions. The identification and modification of some these factors can preclude the need for intervention. The procedure continues to be one of the most common outpatient pediatric procedures. Close vigilance and identification of potential complications is of utmost importance in the ongoing management of the child with middle ear disease. PMID:23905821

Lambert, Elton; Roy, Soham

2013-06-14

152

[Study on middle ear ventilation using positional tympanometry--post mastoidectomy ear].  

PubMed

The middle ear is a cavity surrounded by solid bone, lined with mucosa with a lumen filled with gas. To examine this unique ventilation system under atmospheric pressure, the middle ear pressure of 50 normal ears was previously examined. Positional tympanometry, whereby the middle ear pressure is increased as the subject assumes the lateral position under atmospheric pressure was used. As a result, (1) The middle ear pressure was elevated by the change from the sitting position to the lateral position. Venous pressure was regarded as causative factor of this pressure elevation. (2) The elevation of the middle ear pressure in the lateral position suggested gas production from the mastoid cells of the middle ear. In this study, a proportion of the mastoid cells were removed to resect a tumor of the internal acoustic meatus in conjunction with resection of an acoustic tumor. After resection the area was filled with fascia and fatty tissue. The middle ear pressure of each subject was monitored to determine the effect of a decrease in the mastoid cell volume on middle ear pressure. The results were continuously recorded every 12 seconds for the lower ear when the subjects were in the lateral position. The following results were obtained. (1) The elevation of the middle ear pressure due to positional change among subjects which had had acoustic tumors resected was noticeably greater than the elevation in normal ears. This is thought to have been the result of an elevation in cerebrospinal fluid pressure attributable to positional change, along with an elevation in intravenous pressure. (2) We made comparisons of increases in middle ear pressure 10 minutes after assuming the lateral position in 14 ears after acoustic tumor resection and in 21 normal ears. No noticeable differences were found in the middle ear pressure increases between the two groups despite the fact that the volume of the mastoid cells in the group that had tumors resected had been greatly reduced. PMID:8551378

Ebihara, H

1995-12-01

153

Hyperalgesic properties of 15-lipoxygenase products of arachidonic acid.  

PubMed Central

Induction of hyperalgesia by leukotriene B4 (LTB4), a potent chemotactic factor for polymorphonuclear leukocytes (PMNLs), depends on the generation by cutaneous PMNLs of mediators that are probably derived from the 15-lipoxygenation of arachidonic acid. The capacity of dihydroxyeicosatetraenoic acid (diHETE) products of the 15-lipoxygenation of arachidonic acid in PMNL to elicit hyperalgesia was evaluated by assessing the effects of intradermal injection of synthetic diHETEs on the pressure nociceptive threshold in rats. (8R,15S)-Dihydroxyeicosa-(5E-9,11,13Z)-tetraenoic acid [(8R,15S)-diHETE] produced a dose-dependent hyperalgesia, as measured by decrease in threshold for paw withdrawal. The isomer (8S,15S)-diHETE antagonized in a dose-dependent manner this hyperalgesia due to (8R,15S)-diHETE but did not suppress prostaglandin E2-induced hyperalgesia. (8S,15S)-DiHETE produced a dose-dependent hypoalgesia, as reflected by an increase in nociceptive threshold, suggesting a contribution of endogenous (8R,15S)-diHETE to normal nociceptive threshold. The hypoalgesic effect of (8S,15S)-diHETE was blocked by corticosteroids but not by the cyclooxygenase inhibitor indomethacin. Neither (8R,15S)-dihydroxyeicosa-(5,15E-9,11Z)-tetraenoic acid nor (8R,15S)-dihydroxyeicosa-(5,11E-9,13Z)-tetraenoic acid exhibited any hyperalgesic or hypoalgesic activity. The stereospecificity of the effect of (8R,15S)-diHETE suggests that the induction of hyperalgesia is a receptor-dependent phenomenon and that (8S,15S)-diHETE may be an effective receptor-directed antagonist. The (8R,15S)-diHETE and (8S,15S)-diHETE from PMNL, keratinocytes, and other epithelial cells may modulate normal primary afferent function and contribute to inflammatory hyperalgesia.

Levine, J D; Lam, D; Taiwo, Y O; Donatoni, P; Goetzl, E J

1986-01-01

154

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

2013-06-15

155

Possible involvement of ?-endorphin in docosahexaenoic acid-induced antinociception.  

PubMed

We have previously demonstrated that the n-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) has an antinociceptive effect on various pain stimuli in a naloxone-reversible manner. In the present study, the role of the endogenous opioid peptide ?-endorphin in DHA-induced antinociception was examined. DHA-induced antinociception was abolished when mice were pretreated with the ?-opioid receptor antagonist ?-funaltrexamine (?-FNA) and the ?-opioid receptor antagonist naltrindole, but not by the ?-opioid receptor antagonist nor-binaltorphimine (nor-BNI) in the acetic acid-induced writhing test. In the radioligand binding assay, DHA itself did not have affinity for ?- , ?- or ?-opioid receptors. On the other hand, the pretreatment of anti-?-endorphin antiserum inhibited DHA-induced antinociception. Furthermore, the intracerebroventricular injection of DHA dose-dependently reduced writhing behavior, and this effect was inhibited by d-Phe-Cys-Tyr-Orn-Thr-Pen-Thr-NH(2) (CTOP) and naltrindole, but not nor-BNI. ?-endorphin-induced antinociception was inhibited by the pretreatment of ?-FNA, but not naltrindole or nor-BNI, and its levels in plasma were increased by DHA treatment. These findings suggest that the induction of antinociception by DHA may partially involve the ?-opioid receptor via the release of ?-endorphin. PMID:21658380

Nakamoto, Kazuo; Nishinaka, Takashi; Ambo, Akihiro; Mankura, Mitsumasa; Kasuya, Fumiyo; Tokuyama, Shogo

2011-06-01

156

14 CFR 67.105 - Ear, nose, throat, and equilibrium.  

Code of Federal Regulations, 2013 CFR

... 2 2013-01-01 2013-01-01 false Ear, nose, throat, and equilibrium. 67.105...First-Class Airman Medical Certificate § 67.105 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards...

2013-01-01

157

14 CFR 67.205 - Ear, nose, throat, and equilibrium.  

Code of Federal Regulations, 2013 CFR

... 2 2013-01-01 2013-01-01 false Ear, nose, throat, and equilibrium. 67.205...Second-Class Airman Medical Certificate § 67.205 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards...

2013-01-01

158

14 CFR 67.305 - Ear, nose, throat, and equilibrium.  

Code of Federal Regulations, 2013 CFR

... 2 2013-01-01 2013-01-01 false Ear, nose, throat, and equilibrium. 67.305...Third-Class Airman Medical Certificate § 67.305 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards...

2013-01-01

159

14 CFR 67.105 - Ear, nose, throat, and equilibrium.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Ear, nose, throat, and equilibrium. 67.105 Section 67.105 Aeronautics... § 67.105 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a first-class airman...

2010-01-01

160

14 CFR 67.205 - Ear, nose, throat, and equilibrium.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Ear, nose, throat, and equilibrium. 67.205 Section 67.205 Aeronautics... § 67.205 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a second-class airman...

2009-01-01

161

14 CFR 67.105 - Ear, nose, throat, and equilibrium.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Ear, nose, throat, and equilibrium. 67.105 Section 67.105 Aeronautics... § 67.105 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a first-class airman...

2009-01-01

162

14 CFR 67.205 - Ear, nose, throat, and equilibrium.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Ear, nose, throat, and equilibrium. 67.205 Section 67.205 Aeronautics... § 67.205 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a second-class airman...

2010-01-01

163

14 CFR 67.305 - Ear, nose, throat, and equilibrium.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Ear, nose, throat, and equilibrium. 67.305 Section 67.305 Aeronautics... § 67.305 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a third-class airman...

2010-01-01

164

14 CFR 67.305 - Ear, nose, throat, and equilibrium.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Ear, nose, throat, and equilibrium. 67.305 Section 67.305 Aeronautics... § 67.305 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a third-class airman...

2009-01-01

165

Playing by Ear: Foundation or Frill?  

ERIC Educational Resources Information Center

|Many people divide musicians into two types: those who can read music and those who play by ear. Formal music education tends to place great emphasis on producing musically literate performers but devotes much less attention to teaching students to make music without notation. Some would suggest that playing by ear is a specialized skill that is…

Woody, Robert H.

2012-01-01

166

TOPICAL REVIEW: Pressure difference receiving ears  

Microsoft Academic Search

Directional sound receivers are useful for locating sound sources, and they can also partly compensate for the signal degradations caused by noise and reverberations. Ears may become inherently directional if sound can reach both surfaces of the eardrum. Attempts to understand the physics of such pressure difference receiving ears have been hampered by lack of suitable experimental methods. In this

Axel Michelsen; Ole Næsbye Larsen

2008-01-01

167

Reading disability and middle ear disease.  

PubMed Central

The association between specific reading disability and middle ear disease was investigated in a longitudinal study of 962 children followed from age 5 to 11. No significant differences were found in the prevalence of middle ear abnormalities between the reading disabled group (n = 49) and the remainder.

Share, D L; Chalmers, D; Silva, P A; Stewart, I A

1986-01-01

168

Human ear recognition based on block segmentation  

Microsoft Academic Search

A new human ear recognition approach based on block segmentation is proposed in this paper. In this method, an original ear image is partitioned into several smaller sub-images, then the sub-images are extracted by features, As a result, the lower dimension space features that can replace the original images are obtained. Finally the pattern classification can be implemented by the

Wang Xiaoyun; Yuan Weiqi

2009-01-01

169

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

170

Playing by Ear: Foundation or Frill?  

ERIC Educational Resources Information Center

Many people divide musicians into two types: those who can read music and those who play by ear. Formal music education tends to place great emphasis on producing musically literate performers but devotes much less attention to teaching students to make music without notation. Some would suggest that playing by ear is a specialized skill that is…

Woody, Robert H.

2012-01-01

171

The development of the vertebrate inner ear  

Microsoft Academic Search

The inner ear is a complex sensory organ responsible for balance and sound detection in vertebrates. It originates from a transient embryonic structure, the otic vesicle, that contains all of the information to develop autonomously into the mature inner ear. We review here the development of the otic vesicle, bringing together classical embryological experiments and recent genetic and molecular data.

Miguel Torres; Fernando Giráldez

1998-01-01

172

Tests For Assessing Inner-Ear Dysfunction.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. Quantitative tests of vestibular (inner-ear) and visual-motor function have been developed. Previous clinical tests for assessing inner-ear dysfunction were time-con...

1983-01-01

173

Surgical anatomy of the rat middle ear  

Microsoft Academic Search

This study was designed to aid experimental otologic studies of the rat middle ear. The topographic anatomy of the albino rat middle ear is described. A set of microphotographs with matching illustrations presents the structural details at several surgical exposures. Anatomic differences between the rat, guinea pig, and cat are noted. (Otolaryngol Head Neck Surg 1997;117:438-47.)

RICHARD F. JUDKINS; HONGYAN LI

1997-01-01

174

PHONETICS EAR-TRAINING - DESIGN AND DURATION  

Microsoft Academic Search

Study of the product of routine phonetics ear- training revealed a number of effects. The goal\\/benchmark was mastery of the sounds of the IPA (including Cardinal Vowels). Students with no previous experience of phonetics were followed through a typical one year ear-training programme; their ability to recognise sounds was tested at two points during the year. Vowel identification findings confirmed

Patricia D. S. Ashby

2007-01-01

175

Pathophysiology of inner ear fluid imbalance.  

PubMed

Maintenance of homeostasis of inner ear fluids and biochemical integrity of inner ear tissue are essential for proper functioning of the auditory and vestibular end organs. Although various regulatory mechanisms exist in a different portion of the labyrinth, the inner ear is known to respond to systemic challenges. The association of Meniere's syndrome with an imbalance of inner ear fluid homeostasis has been hypothesized for the past century. Among many factors, the effects of hormonal imbalance on inner ear fluid composition and inner ear function have however scarcely been studied. The purpose of this study was to explore the relationship between the autonomic nervous system and inner ear function and possible mechanisms of functional disturbances in an experimental condition. An infusion of supraphysiologic amounts of epinephrine, a stress related hormone, resulted in an elevation of osmolality in serum and perilymph. Furthermore, the infusion of epinephrine resulted in elevation of threshold, prolongation of latency, and depression of amplitude in the compound action potential of the auditory nerve. These findings were most marked at high frequencies. We hypothesized that the epinephrine-induced hearing loss was brought about by an increase in perilymphatic osmolality, as well as by the ionic imbalance caused by the osmotic gradient. Since emotional stress has been implicated as a mechanism of inducing a Meniere's attack, evaluation of the relationship between the autonomic system and cochlear function may contribute to the understanding of possible mechanisms of inner ear dysfunction caused by hormonal imbalances. PMID:1843177

Juhn, S K; Ikeda, K; Morizono, T; Murphy, M

1991-01-01

176

Human Ear Detection From 3D Side Face Range Images  

Microsoft Academic Search

Ear is a new class of relatively stable biometrics which is not affected by facial expressions, cosmetics and eye glasses.\\u000a To use ear biometrics for human identification, ear detection is the first part of an ear recognition system. In this chapter\\u000a we propose two approaches for locating human ears in side face range images: (a) template matching based ear detection

H. Chen; B. Bhanu

177

Cholera Toxin B Subunit Activates Arachidonic Acid Metabolism  

PubMed Central

Cholera toxin (CT) increases intestinal secretion of water and electrolytes and modulates the mucosal immune response by stimulating cellular synthesis of arachidonic acid (AA) metabolites (e.g., prostaglandin E2), as well as the intracellular second messenger cyclic AMP (cAMP). While much is known about the mechanism of CT stimulation of adenylate cyclase, the toxin’s activation of phospholipase A2, which results in increased hydrolysis of AA from membrane phospholipids, is not well understood. To determine whether CT activation of AA metabolism requires CT’s known enzymatic activity (i.e., ADP-ribosylation of GS?), we used native CT and a mutant CT protein (CT-2*) lacking ADP-ribose transferase activity in combination with S49 wild-type (WT) and S49 cyc? murine Theta (Th)1.2-positive lymphoma cells deficient in GS?. The experimental results showed that native CT stimulated the release of [3H[AA from S49 cyc? cells at a level similar to that for S49 WT cells, indicating that GS? is not essential for this process. Further, levels of cAMP in the CT-treated cyc? cells remained the same as those in the untreated control cells. The ADP-ribosyltransferase-deficient CT-2* protein, which was incapable of increasing synthesis of cAMP, displayed about the same capacity as CT to evoke the release of [3H]AA metabolites from both S49 WT and cyc? cells. We concluded that stimulation of arachidonate metabolism in S49 murine lymphoma cells by native CT does not require enzymatically functional CT, capable of catalyzing the ADP-ribosylation reaction. These results demonstrated for the first time that stimulation of adenylate cyclase by CT and stimulation of AA metabolism by CT are not necessarily coregulated. In addition, the B subunits purified from native CT and CT-2* both simulated the release of [3H]AA from S49 cyc? cells and murine monocyte/macrophage cells (RAW 264.7), suggesting a receptor-mediated cell activation process of potential importance in enhancing immune responses to vaccine components.

Peterson, Johnny W.; Finkelstein, Richard A.; Cantu, Juan; Gessell, Deborah L.; Chopra, Ashok K.

1999-01-01

178

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

179

Different arachidonate and palmitate binding capacities of the human red cell membrane  

Microsoft Academic Search

Human red cell membrane bindings of arachidonate and palmitate at pH 7.3 are investigated at temperatures between 0 and 38°C by equilibrating ghosts with the long-chain fatty acids bound to bovine serum albumin in molar ratios (v) within the physiological range (K\\u000a\\u000adm\\u000a). The temperature-independent arachidonate binding capacity, 5.5 ± 0.5 nmol g–1 packed ghosts, is approximately fivefold smaller

I. N. Bojesen; E. Bojesen

1994-01-01

180

Arachidonic acid autoxidation in an aqueous media effect of ?-tocopherol, cysteine and nucleic acids  

Microsoft Academic Search

The autoxidation of arachidonic acid dispersed in aqueous media was evaluated simultaneously with and without different agents,\\u000a e.g., ?-tocopherol at different concentrations, cysteine, DNA and RNA. The autoxidation rate of arachidonic acid was evaluated\\u000a by quantitative gas liquid chromatography (GLC) determination of the unoxidized acid and by spectrophotometric measurement\\u000a of conjugated dienes. ?-Tocopherol exhibited a prooxidant activity at concentrations of

Bruno Bazin; Josiane Cillard; Jean-Pierre Koskas; Pierre Cillard

1984-01-01

181

Behavioral suppression induced by cannabinoids is due to activation of the arachidonic acid cascade in rats  

Microsoft Academic Search

Tetrahydrocannabinol (THC) is the principle psychoactive ingredient of marijuana and produces various psychoactive effects through the brain cannabinoid (CB1) receptor. The CB1 receptor belongs to the seven-transmembrane domain family of G-protein-coupled receptors and is involved in the arachidonic acid cascade in the brain. Few reports have attempted to clarify the functional role of endogenous cannabinoid and the arachidonic acid cascade

Taku Yamaguchi; Yukihiro Shoyama; Shigenori Watanabe; Tsuneyuki Yamamoto

2001-01-01

182

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

183

Regulation of the arachidonic acid-stimulated respiratory burst in neutrophils by intracellular and extracellular calcium  

Microsoft Academic Search

The respiratory burst is an important physiological function of the neutrophils in killing the bacteria invading in human\\u000a body. We used chemiluminescence method to measure the exogenous arachidonic acid-stimulated respiratory burst, and measured\\u000a the cytosolic free calcium concentration in neutrophils by the fluorescence method. It was found that, on one hand, the arachidonic\\u000a acid-stimulated respiratory burst was enhanced by elevating

Shaokun Chuai; Tianhui Hu; Jiang Liu; Xun Shen

2001-01-01

184

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

185

Effects of middle-ear disorders on power reflectance measured in cadaveric ear canals  

PubMed Central

Objective Reflectance measured in the ear canal offers a noninvasive method to monitor the acoustic properties of the middle ear, and few systematic measurements exist on the effects of various middle-ear disorders on the reflectance. This work utilizes a human cadaver-ear preparation and a mathematical middle-ear model to both measure and predict how power reflectance ? is affected by the middle-ear disorders of static middle-ear pressures, middle-ear fluid, fixed stapes, disarticulated incudo-stapedial joint, and tympanic-membrane perforations. Design ? was calculated from ear-canal pressure measurements made on human-cadaver ears in the normal condition and five states: (1) positive and negative pressure in the middle-ear cavity, (2) fluid-filled middle ear, (3) stapes fixed with dental cement, (4) incudo-stapedial joint disarticulated, and (5) tympanic-membrane perforations. The middle-ear model of Kringlebotn (1988) was modified to represent the middle-ear disorders. Model predictions are compared to measurements. Results For a given disorder, the general trends of the measurements and model were similar. The changes from normal in ?, induced by the simulated disorder, generally depend on frequency and the extent of the disorder (except for the disarticulation). Systematic changes in middle-ear static pressure (up to ± 300 daPa) resulted in systematic increases in ?. These affects were most pronounced for frequencies up to 1000 to 2000 Hz. Above about 2000 Hz there were some asymmetries in behavior between negative and positive pressures. Results with fluid in the middle-ear air space were highly dependent on the percentage of the air space that was filled. Changes in ? were minimal when a smaller fraction of the air space was filled with fluid, and as the air space was filled with more saline, ? increased at most frequencies. Fixation of the stapes generally resulted in a relatively small low-frequency increase in ?. Disarticulation of the incus with the stapes led to a consistent low-frequency decreases in ? with a distinctive minimum below 1000 Hz. Perforations of the tympanic membrane resulted in a decrease in ? for frequencies up to about 2000 Hz; at these lower frequencies, smaller perforations led to larger changes from normal as compared to larger perforations. Conclusions These preliminary measurements help assess the utility of power reflectance as a diagnostic tool for middle-ear disorders. In particular, the measurements document (1) the frequency ranges for which the changes are largest and (2) the extent of the changes from normal for a spectrum of middle-ear disorders.

Merchant, Gabrielle R.; Horton, Nicholas J.

2011-01-01

186

Arachidonate 12-lipoxygenases with reference to their selective inhibitors  

SciTech Connect

Lipoxygenase is a dioxygenase recognizing a 1-cis,4-cis-pentadiene of polyunsaturated fatty acids. The enzyme oxygenates various carbon atoms of arachidonic acid as a substrate and produces 5-, 8-, 12- or 15-hydroperoxy eicosatetraenoic acid with a conjugated diene chromophore. The enzyme is referred to as 5-, 8-, 12- or 15-lipoxygenase, respectively. Earlier we found two isoforms of 12-lipoxygenase, leukocyte- and platelet-type enzymes, which were distinguished by substrate specificity, catalytic activity, primary structure, gene intron size, and antigenicity. Recently, the epidermis-type enzyme was found as the third isoform. Attempts have been made to find isozyme-specific inhibitors of 12-lipoxygenase, and earlier we found hinokitol, a tropolone, as a potent inhibitor selective for the platelet-type 12-lipoxygenase. More recently, we tested various catechins of tea leaves and found that (-)-geotechnical gallate was a potent and selective inhibitor of human platelet 12-lipoxygenase with an IC{sub 5} of 0.14 {mu}M. The compound was much less active with 12-lipoxygenase of leukocyte-type, 15-, 8-, and 5-lipoxygenases, and cyclo oxygenases-1 and -2.

Yamamoto, Shozo [Department of Food and Nutrition, Faculty of Home Economics, Kyoto Women's University, Imakumano, Higashiyama-ku, Kyoto 605-8501 (Japan)]. E-mail: yamamosh@kyoto-wu.ac.jp; Katsukawa, Michiko [Department of Food and Nutrition, Faculty of Home Economics, Kyoto Women's University, Imakumano, Higashiyama-ku, Kyoto 605-8501 (Japan); Nakano, Ayumi [Department of Food and Nutrition, Faculty of Home Economics, Kyoto Women's University, Imakumano, Higashiyama-ku, Kyoto 605-8501 (Japan); Hiraki, Emi [Department of Food and Nutrition, Faculty of Home Economics, Kyoto Women's University, Imakumano, Higashiyama-ku, Kyoto 605-8501 (Japan); Nishimura, Kohji [Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504 (Japan); Jisaka, Mitsuo [Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504 (Japan); Yokota, Kazushige [Faculty of Life and Environmental Science, Shimane University, Matsue, Shimane 690-8504 (Japan); Ueda, Natsuo [Department of Biochemistry, School of Medicine, Kagawa University, Miki-cho, Kita-gun, Kagawa 761-0793 (Japan)

2005-12-09

187

Arachidonic acid metabolism in fibroblasts derived from canine myocardium  

SciTech Connect

Canine fibroblasts from normal or healing infarcted myocardium were grown in culture. The cells were morphologically indistinguishable, but the doubling time of cells from healing myocardium was 39.6 +/- 3.5 hr whereas that of normals was 24 +/- 3.7 (n=5, p < .025). Fibroblasts incorporated (/sup 3/H)arachidonate (AA) into phospholipids. Calcium ionophore A23187 (10 ..mu..M) caused release and metabolism of (/sup 3/H) AA. A23187 or AA (10..mu..M) induced production of 6-keto PGF1..cap alpha.., PGE2, and a hydroxy metabolite of AA. RIA of 6-keto PGF1..cap alpha.. showed that subconfluent cells from healing myocardium produced 1202 +/- 354 pg/mg protein whereas that of normals was 551 +/- 222 (n=7, p < .025). Histamine and bradykinin also induced AA metabolism but were less potent. They examined the effect of AA released from deteriorating myocytes on AA metabolism by cultured fibroblasts. They confirmed that isolated myocytes labelled with (/sup 3/H)AA released but did not metabolize (/sup 3/H)AA. In coincubations, fibroblasts incorporated myocyte-derived AA. Subsequent stimulation of the fibroblasts with A23187 induced the synthesis of 6-keto PGF1..cap alpha.., PGE2 and a hydroxy metabolite. The fibroblast content of healing myocardium was 35-1000 times that of normal tissue (n=7). Thus even a moderate change in AA metabolism, amplified by the AA released from deteriorating myocytes, may be a significant physiologic or pathologic event.

Weber, D.R.; Prescott, S.M.

1986-03-05

188

Inhibitory effect of melanin precursors on arachidonic acid peroxidation.  

PubMed

A possible role of melanin precursors in lipid peroxidation was investigated using the lipoxygenase catalysed oxygenation of arachidonic acid (AA) as a model system. Polarographical monitoring of oxygen consumption showed that, among the metabolites examined, 5,6-dihydroxyindole (DHI) was the most active in inhibiting AA oxygenation catalysed by 15-lipoxygenase. The inhibition was found to be concentration-dependent with an IC50 value of 15 microM. Similar effects were observed in the case of the 5-lipoxygenase promoted reaction. Periodical HPLC analysis of the oxidation mixture showed that, in the presence of DHI, the rate of substrate consumption is markedly reduced. The inhibitory potency was significantly increased either by preincubation of DHI with the enzyme or by increasing the time of residence of the indole in aerated buffer solutions prior to contact with the enzyme. Addition of catalase to the incubation mixture resulted in a partial removal of DHI inhibition. From these and other experiments, an inhibition mechanism is proposed which involves inactivation of the enzyme by reactive species, especially hydrogen peroxide, arising from DHI autoxidation. PMID:8504152

Napolitano, A; Palumbo, A; Misuraca, G; Prota, G

1993-06-12

189

Docosahexaenoic and arachidonic acid concentrations in human breast milk worldwide.  

PubMed

Concentrations of the long-chain polyunsaturated fatty acids (LCPUFAs) docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6) in human breast milk are important indicators of infant formula DHA and AA concentrations, and recent evidence suggests that neural maturation of breastfed infants is linked to breast-milk LCPUFA concentrations. We report a descriptive meta-analysis that considered 106 studies of human breast milk culled to include only studies that used modern analysis methods capable of making accurate estimates of fatty acid (FA) profiles and criteria related to the completeness of reporting. The final analysis included 65 studies of 2474 women. The mean (+/-SD) concentration of DHA in breast milk (by wt) is 0.32 +/- 0.22% (range: 0.06-1.4%) and that of AA is 0.47 +/- 0.13% (range: 0.24-1.0%), which indicates that the DHA concentration in breast milk is lower than and more variable than that of AA. The highest DHA concentrations were primarily in coastal populations and were associated with marine food consumption. The correlation between breast-milk DHA and AA concentrations was significant but low (r = 0.25, P = 0.02), which indicates that the mean ratio of DHA to AA in regional breast milk varies widely. This comprehensive analysis of breast-milk DHA and AA indicates a broad range of these nutrients worldwide and serves as a guide for infant feeding. PMID:17556680

Brenna, J Thomas; Varamini, Behzad; Jensen, Robert G; Diersen-Schade, Deborah A; Boettcher, Julia A; Arterburn, Linda M

2007-06-01

190

Human antimicrobial proteins in ear wax.  

PubMed

The external auditory canal is vulnerable to bacterial infections, but little is known about thechemical compositions of ear wax regarding antimicrobial peptides. We, therefore, studied the proteinconcentrations of ten well-known human antimicrobial peptides from ear wax.Twenty ear wax samples from healthy individuals were analysed using enzyme-linked immunosorbent assay (ELISA) to determine theprotein concentrations of the antimicrobial peptides hBD1-3, lactoferrin, LL-37, BPI, hSLPI and HNP1-3. All ten antimicrobial peptides are present in ear wax. Some of these proteins seem to be merelycell-bound in ear wax. Antimicrobial peptides in ear wax prevent bacteria and fungi from causing infections inthe external auditory canal. The role and importance of these proteins for the blind-ending ear externalcanal is discussed. If this local defence system fails, infections of the external auditory canal may result.The knowledge about the presence of antimicrobial peptides in cerumen may lead to new concepts ofthe local treatment of external auditory canal diseases in the future. PMID:21298458

Schwaab, M; Gurr, A; Neumann, A; Dazert, S; Minovi, A

2011-02-06

191

Vasopressin induces release of arachidonic acid from vascular smooth muscle cells  

SciTech Connect

Cultured smooth muscle cells (A-10), derived from rat thoracic aorta, have vascular (V/sub 1/) vasopressin receptors. They have previously shown that these receptors mediate phosphatidylinositol turnover, Ca/sup 2 +/ efflux, and inhibition of isoproterenol-induced increases in cAMP. Here they studied the effect of vasopressin on arachidonic acid metabolism of A-10 cells. Cells were incubated for 18-20 hr with (/sup 3/H)-arachidonic acid (80 Ci/mmol). Vasopressin stimulated release of arachidonic acid in a time- and dose-dependent manner. Significant release of arachidonic acid was observed after 4 min with 10/sup -9/ M vasopressin. Maximum release was reached 4 min after addition of 10/sup -7/ M vasopressin (1100 dpm/10/sup 6/ cells). About 800 dmp were released after 1 and 4 min with 10/sup -7/ M and 10/sup -8/ M vasopressin, respectively. The vasopressin-stimulated release of arachidonic acid was blocked by the specific V/sub 1//V/sub 2/ vasopressin antagonist d(CH2)5D-Tyr(Et)VAVP. These data indicate that vascular smooth muscle cells increase arachidonic acid release in response to vasopressin. This response is likely mediated by V/sub 1/ receptors.

Grillone, L.R.; Clark, M.A.; Heckman, G.; Schmidt, D.; Stassen, F.L.; Crooke, S.T.

1986-05-01

192

Release of arachidonic acid from human lymphocytes in response to mitogenic lectins  

PubMed Central

After exposure to mitogenic lectins in vitro, human mononuclear cells (95% lymphocytes) that had been prelabeled with [14C]arachidonic acid rapidly released a portion of their radioactivity in the medium. Most of the released radioactivity was demonstrated to be free arachidonic acid. Although other sources are not excluded, the most important source of cell-bound radioactivity in the release reaction appeared to be phosphatidylinositol, suggesting that at least part of the response is occurring through an increase in phospholipase A2 activity. By gas liquid chromatography, other fatty acids were also shown to be released, but there was considerable selectivity in the response for arachidonic acid. The response was dependent on the availability of free Ca++ in the medium and was enhanced by serum proteins and unlabeled arachidonic acid. Most of the response appeared to be from the the lymphocytes themselves rather than from contaminating cells. The rapid generation of free arachidonic acid in response to mitogenic lectins suggests a possible role for arachidonic acid metabolites in the activation process.

1979-01-01

193

Earedness: Left-eared and right-eared listeners  

NASA Astrophysics Data System (ADS)

The Huggins pitch (HP) stimulus known as HP- is created with a broadband background noise having an interaural phase difference of zero, together with a narrow boundary region wherein the interaural phase varies with frequency. At the spectral center of the boundary region the interaural phase is 180 deg. Therefore, HP- is symmetrical with respect to the two ears. Despite the symmetry, most listeners hear the HP image strongly lateralized to one side of the head. Some hear it on the right; others hear it on the left. Two surveys, involving 51 listeners, found that these perceptions do not change when the headphones are reversed. Extensive experiments with five listeners found that the lateralization directions were usually insensitive to variations in the frequency of the boundary region (more than two octaves). The left or right preference was strong enough that listeners chose alias locations (differing from a more central location by 360 deg) on the preferred side when various frequency-independent interaural delays and phase shifts were added to the HP stimulus. The experiments suggest that given ambiguous stimuli, listeners exhibit earedness-a preference similar to, but not as strong as, handedness. [Work supported by the NIDCD Grant DC 00181.

Hartmann, William M.; Zhang, Peter Xinya; Culling, John F.

2001-05-01

194

A Novel Algorithm for Autologous Ear Reconstruction  

PubMed Central

Sculpting a tridimensional autologous rib cartilage framework is essential to restore a natural ear shape and becomes routine with preoperative training, but management of the skin is the key to minimizing complications. Here the authors provide a classification scheme to manage auricular skin: Type 1 is a Z-plasty with transposition of the lobule; type 2 is a transfixion incision of the microtic ear; type 3 exposes the cartilage remnants through a cutaneous incision. They also explain how to choose between the three types, depending upon the auricular skin potential. With training and method, results in ear reconstruction using autologous rib cartilage are excellent and reproducible.

Firmin, Francoise; Marchac, Alexandre

2011-01-01

195

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,

196

The Ear Pages - Nobel Prize Educational Game  

NSDL National Science Digital Library

The 1961 Nobel Prize in Physiology or Medicine was awarded for the discovery of how sound is analyzed and communicated in the cochlea in the inner ear. Explore "The Ear Pages" and collect the snail shaped symbols of the cochlea to gain chances to answer a question correct in the quiz! (The cochlea works as a frequency/pitch analyzer in the inner ear.) You can choose between three levels of quizzes ÃÂ beginner, advanced and expert. If you manage to get all the answers correct you will appear on the "High score of the week" list!

2009-01-01

197

Heart arachidonic acid is uniquely sensitive to dietary arachidonic acid and docosahexaenoic acid content in domestic piglets  

PubMed Central

This study determined the sensitivity of heart and brain arachidonic acid (ARA) and docosahexaenoic acid (DHA) to the dietary ARA level in a dose-response design with constant, high DHA in neonatal piglets. On day 3 of age, pigs were assigned to 1 of 6 dietary formulas varying in ARA/DHA as follows (% fatty acid, FA/FA): (A1) 0.1/1.0; (A2) 0.53/1.0; (A3-D3) 0.69/1.0; (A4) 1.1/1.0; (D2) 0.67/0.62; (D1) 0.66/0.33. At necropsy (day 28) higher levels of dietary ARA were associated with increased heart and liver ARA, while brain ARA remained unaffected. Dietary ARA had no effect on tissue DHA accretion. Heart was particularly sensitive, with pigs in the intermediate groups having different ARA (A2, 18.6 ± 0.7%; A3, 19.4 ± 1.0%) and a 0.17% increase in dietary ARA resulted in a 0.84% increase in heart ARA. Further investigations are warranted to determine the clinical significance of heart ARA status in developing neonates.

Tyburczy, Cynthia; Kothapalli, Kumar S. D.; Park, Woo Jung; Blank, Bryant S.; Bradford, Kathryn Lee; Zimmer, J. Paul; Butt, Christopher M.; Salem, Norman; Brenna, J. Thomas

2011-01-01

198

Heart arachidonic acid is uniquely sensitive to dietary arachidonic acid and docosahexaenoic acid content in domestic piglets.  

PubMed

This study determined the sensitivity of heart and brain arachidonic acid (ARA) and docosahexaenoic acid (DHA) to the dietary ARA level in a dose-response design with constant, high DHA in neonatal piglets. On day 3 of age, pigs were assigned to 1 of 6 dietary formulas varying in ARA/DHA as follows (% fatty acid, FA/FA): (A1) 0.1/1.0; (A2) 0.53/1.0; (A3-D3) 0.69/1.0; (A4) 1.1/1.0; (D2) 0.67/0.62; and (D1) 0.66/0.33. At necropsy (day 28) higher levels of dietary ARA were associated with increased heart and liver ARA, while brain ARA remained unaffected. Dietary ARA had no effect on tissue DHA accretion. Heart was particularly sensitive, with pigs in the intermediate groups having different ARA (A2, 18.6±0.7%; A3, 19.4±1.0%) and a 0.17% increase in dietary ARA resulted in a 0.84% increase in heart ARA. Further investigations are warranted to determine the clinical significance of heart ARA status in developing neonates. PMID:21885269

Tyburczy, Cynthia; Kothapalli, Kumar S D; Park, Woo Jung; Blank, Bryant S; Bradford, Kathryn L; Zimmer, J Paul; Butt, Christopher M; Salem, Norman; Brenna, J Thomas

2011-08-31

199

Role of Cell-Cell Communication in Inhibiting Butyric Acid-Induced T-Cell Apoptosis  

Microsoft Academic Search

We have previously demonstrated that human gingival fibroblasts rescue butyric acid-induced T-cell apo- ptosis via proinflammatory cytokines such as interleukin 6 (IL-6) and IL-11, which are produced by fibroblasts stimulated with butyric acid. In this study, we determined if T-cell adhesion to human gingival fibroblasts influenced the susceptibility of T cells to butyric acid-induced apoptosis. We have shown that the

Tomoko Kurita-Ochiai; Shintaro Seto; Kuniyasu Ochiai

2004-01-01

200

[Study on middle ear ventilation using positional tympanometry--normal ear].  

PubMed

The middle ear is a cavity surrounded by solid bones, lined with mucosa, which has a gas-filled lumen. Cavernous organs such as the ear should have their own ventilation system under atmospheric pressure. The mechanism of ventilation in the middle ear has not been sufficiently clarified. Ventilation performed in the middle ear may be classified into two types: 1) passive ventilation via the Eustachian tube, required in cases of abnormal pressure and 2) unique physiological active ventilation of the middle ear performed under atmospheric pressure and not involving the Eustachian tube. The purpose of the present study is to prove the existence of this active ventilation under atmospheric pressure. The subjects were 50 normal ears and elevation of middle ear pressure in the lateral position (determined by positional tympanometry) was studied. The change in the peak level, on tympanometry, was used as an index. The results were continuously recorded every 12 seconds. The following results were obtained. 1. Middle ear pressure was elevated by changing from the sitting to the lateral position. Venous pressure was regarded as a causative factor in this pressure elevation. 2. The elevated middle ear pressure in the lateral position suggested gas production from mastoid cells of the middle ear. The observation that the middle ear pressure was stabilized with the increase in pressure, up to a level of 85-90 mm H2O, indicated the existence of gas leakage from the Eustachian tube and a mechanism for controlling gas production from the mastoid cells of the middle ear. PMID:7629643

Ebihara, H

1995-06-01

201

Indications and Candidacy for Active Middle Ear Implants  

Microsoft Academic Search

Currently, there are two active middle ear implants available commercially: the Vibrant Soundbridge system and the Carina system. A third active middle ear implant, the Esteem, is under clinical evaluation. All devices are indicated for patients with moderate-to-severe hearing loss. Because active middle ear implants are directly coupled to middle ear structures, many of the problems that patients with conventional

F. Wagner; I. Todt; J. Wagner; A. Ernst

2010-01-01

202

Human ear detection from side face range images  

Microsoft Academic Search

Ear detection is an important part of an ear recognition system. In this paper, we address human ear detection from side face range images. We introduce a simple and an effective method to detect ears, which has two stages: offline model template building and on-line detection. The model template is represented by an averaged histogram of shape index. The on-line

Hui Chen; Bir Bhanu

2004-01-01

203

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

2013-08-06

204

Passive Piezoelectric Prosthesis for the Inner Ear.  

National Technical Information Service (NTIS)

A tubular prosthesis formed by an assembly of electrode segments enclosing an elongated inner chamber, is inserted into the inner ear of a patient for piezoelectric generation of electrical impulses and localized injection thereof in response to externall...

S. A. Fisher A. S. DeReggi

1997-01-01

205

Design Factors and Use of Ear Protection*  

PubMed Central

The problems of protecting the ear against hazardous noise are the subject of a general review, supported where relevant by data from the authors' own researches. Ear protectors are classified into two main types?plugs and muffs—and the general principles of their function and limitations are stated. Examples of representative ear protectors are given in more detail, with particular respect to their relative merits and pure-tone attenuation characteristics. The effects of earplugs on speech communication are considered and the relationships between pure-tone attenuation and protection against continuous noise are discussed in some detail. The results of temporary threshold shift (T.T.S.) reduction studies of the efficiency of V.51R and Selectone-K earplugs in protecting against reverberant and non-reverberant impulsive noises are presented. The design requirements of ear protectors and some of the problems created by them are also outlined. Images

Rice, C. G.; Coles, R. R. A.

1966-01-01

206

Pharmacological characterization of mouse ear PCA.  

PubMed

Effects of some antiallergic agents on homologous passive cutaneous anaphylaxis (PCA) in mouse ear were investigated by means of assessing the amount of extravasated dye. Antihistamines (chlorpheniramine and diphenhydramine) and antiserotonins (methysergide and cyproheptadine) suppressed mouse ear PCA significantly. In contrast, an antagonist of slow reacting substance of anaphylaxis (SRS-A) (FPL 55712) and an inhibitor of SRS-A synthesis (AA-861) did not suppress the reaction. beta-Adrenergic stimulants (isoproterenol and salbutamol) and theophylline, which elevate cyclic AMP (cAMP) levels, also suppressed mouse ear PCA significantly. The antiallergic agents, N(3',4'-dimethoxycinnamoyl)anthranilic acid(N-5') and ketotifen suppressed mouse ear PCA significantly, but disodium cromoglycate (DSCG) failed to suppress the reaction. PMID:2864316

Inagaki, N; Goto, S; Nagai, H; Koda, A

1985-01-01

207

A Comparison of Acid-induced Cell Wall Loosening in Valonia ventricosa and in Oat Coleoptiles.  

PubMed

The acid-induced loosening of cell walls of Valonia ventricosa has been compared to that of frozen-thawed oat coleoptiles. The two acid extension responses are similar in regard to the shape of the pH response curve and the increase in plastic compliance induced by acid treatment. In both systems the acid response can be inhibited by Ca(2+) and in both the removal of the protons leads to a rapid termination of wall loosening. The two responses differ in several significant ways, however. The acid-induced extension of Valonia walls is more rapid than that of coleoptile walls, but of smaller total magnitude. Acid-induced loosening can occur in Valonia without the wall being under tension, but not in coleoptiles. The acid-induced extension of Valonia walls is not inhibited by 8 molar urea, whereas the response in oat coleoptiles is completely inhibited by this treatment. Ethylenediaminetetraacetate (EDTA) can cause wall loosening in Valonia comparable to that produced by low pH, whereas in coleoptiles EDTA causes a much smaller response. These results with Valonia are consistent with a mechanism of acid-induced wall loosening in which a central role is played by the displacement of Ca(2+) from the wall, while the larger part of acid-induced wall loosening in oat coleoptiles appears to be via a different mechanism. PMID:16660834

Tepfer, M; Cleland, R E

1979-05-01

208

Genetic Requirement for Pneumococcal Ear Infection  

PubMed Central

Background Ear infection or otitis media (OM) accounts for most bacterial respiratory infections in children in both developed and developing nations. Streptococcus pneumoniae, nontypeable Haemophilus influenzae, and Moraxella catarrhalis are the major OM pathogens. However, little is known about the genetic basis of bacterial OM largely due to practical difficulties in conducting research in ear infection models and genetically manipulating clinical isolates. Here, we report the first genome-scale in vivo screen for bacterial genes required for ear infection in a chinchilla model by signature tagged mutagenesis (STM), a high throughput mutant screen technique. Methodology/Principal Findings STM strains were constructed with a multi-drug resistant OM isolate ST556 (serotype 19F) and screened in a chinchilla OM model. Out of 5,280 mutants tested, 248 mutants were substantially underrepresented in the mutant pools recovered from the middle ear fluids of the infected chinchillas, indicating the impaired ability to survive and replicate in the middle ears due to genetic disruptions in the chromosome of strain ST556. Further DNA sequencing analysis mapped the mutations to 169 pneumococcal genes. Surprisingly, only 52 of these genes were required for pneumococcal nasopharyngeal colonization in a murine model. This infection site-specific gene requirement was verified by targeted mutagenesis in the selected genes. Conclusions/Significance These findings suggest that there are a subset of pneumococcal genes required for ear infection and that these may be distinct from those required for nasal colonization. Our data thus provide comprehensive gene targets for mechanistic understanding of pneumococcal ear infection. Finally, this study has also developed a model for future genome-scale search for virulence determinants in other pathogens associated with ear infections.

Yang, Jun; O'Brien, Christopher J.; Lee, Scott L.; Mazurkiewicz, Joseph E.; Haataja, Sauli; Yan, Jing-Hua; Gao, George F.; Zhang, Jing-Ren

2008-01-01

209

Arachidonic acid metabolism in silica-stimulated bovine alveolar macrophages  

SciTech Connect

The in vitro production of arachidonic acid (AA) metabolites in adherent bovine alveolar macrophages (BAM) incubated with silica was investigated. BAM were pre-labelled with {sup 3}H-AA, and lipid metabolites released into the culture medium were analyzed by high performance liquid chromatography (HPLC). Lactate dehydrogenase (LDH) release was simultaneously assayed to provide an indication of cell injury. Increasing doses of silica selectively stimulated the 5-lipoxygenase pathway of AA metabolism, while cyclooxygenase metabolite output was suppressed. LDH release increased in a linear, dose-dependent fashion over the range of silica doses used. Moreover, within 15 min following addition of a high silica dose, a shift to the production of 5-lipoxygenase metabolites occurred, accompanied by a reduction in cyclooxygenase products. This rapid alteration in AA metabolism preceded cell injury. To examine the relationship between cytotoxicity and AA metabolite release by BAM exposed to silicas with different cytotoxic and fibrogenic activities, BAM were exposed to different doses of DQ-12, Minusil-5, and Sigma silicas, and carbonyl iron beads. The median effective dose (ED{sub 50}) of each particulate to stimulate the release of AA metabolites and LDH was calculated. The ED{sub 50} values for DQ-12, Minusil-5, and Sigma silica showed that the relative cytotoxicities of the different silicas for BAM corresponded to the relative potencies of the silicas to elicit 5-lipoxygenase metabolites from BAM. These results indicate that the cytotoxic, and presumed fibrogenic potential, of a silica is correlated with the potency to stimulate the release of leukotrienes from AM.

Englen, M.D.

1989-01-01

210

Arachidonic acid release mediated by OX1 orexin receptors  

PubMed Central

Background and purpose: We have previously shown that lipid mediators, produced by phospholipase D and C, are generated in OX1 orexin receptor signalling with high potency, and presumably mediate some of the physiological responses to orexin. In this study, we investigated whether the ubiquitous phospholipase A2 (PLA2) signalling system is also involved in orexin receptor signalling. Experimental approach: Recombinant Chinese hamster ovary-K1 cells, expressing human OX1 receptors, were used as a model system. Arachidonic acid (AA) release was measured from 3H-AA-labelled cells. Ca2+ signalling was assessed using single-cell imaging. Key results: Orexins strongly stimulated [3H]-AA release (maximally 4.4-fold). Orexin-A was somewhat more potent than orexin-B (pEC50= 8.90 and 8.38 respectively). The concentration–response curves appeared biphasic. The release was fully inhibited by the potent cPLA2 and iPLA2 inhibitor, methyl arachidonyl fluorophosphonate, whereas the iPLA2 inhibitors, R- and S-bromoenol lactone, caused only a partial inhibition. The response was also fully dependent on Ca2+ influx, and the inhibitor studies suggested involvement of the receptor-operated influx pathway. The receptor-operated pathway, on the other hand, was partially dependent on PLA2 activity. The extracellular signal-regulated kinase, but not protein kinase C, were involved in the PLA2 activation at low orexin concentrations. Conclusions and implications: Activation of OX1 orexin receptors induced a strong, high-potency AA release, possibly via multiple PLA2 species, and this response may be important for the receptor-operated Ca2+ influx. The response coincided with other high-potency lipid messenger responses, and may interact with these signals.

Turunen, Pauli M; Ekholm, Marie E; Somerharju, Pentti; Kukkonen, Jyrki P

2010-01-01

211

Phosphatidate-induced arachidonic acid mobilization in mouse peritoneal macrophages.  

PubMed

Phosphatidate (PA) is synthesized by a variety of cells in response to physiological agonists. Addition of PA vesicles to [3H]arachidonic acid (AA)-labeled macrophages was found to induce the release of radiolabel in a dose- and time-dependent manner. This effect correlated with the uptake of PA by the macrophages and appeared to be attributable to PA itself and not to a PA metabolite. In parallel with AA release, PA induced a rapid increase in lysophosphatidylcholine in cells prelabeled with [14C]glycerol. Down-regulation of protein kinase C by long term exposure of the cells to phorbol myristate acetate or cell treatment with the protein kinase C inhibitor staurosporine did not affect the PA response. Also, removal of external calcium or cell treatment with the calmodulin antagonist trifluoperazine did not affect PA-induced AA release, while inhibiting the responses to zymosan, phorbol 12-myristate 13-acetate, and ionophore A23187. PA-induced AA release was not affected by intracellular calcium depletion by treatment with quin2/AM in the presence of EGTA. When assayed toward an AA-containing substrate, PA was able to enhance phospholipase A2 activity from cell homogenates in the absence of calcium. The dose dependence and magnitude of the PA effect correlated with those observed for PA-induced AA release in whole cells. Inclusion of ATP in the assay mixture did not affect the activity of the PA-stimulated phospholipase A2. These findings suggest a role for PA in the cascade of events leading to AA release in macrophages through Ca(2+)-independent stimulation of an AA-selective phospholipase A2. PMID:7929404

Fernández, B; Balboa, M A; Solís-Herruzo, J A; Balsinde, J

1994-10-28

212

Maitotoxin: Effects on calcium channels, phosphoinositide breakdown, and arachidonate release in pheochromocytoma PC12 cells  

SciTech Connect

Maitotoxin (MTX) increases formation of (3H)inositol phosphates from phosphoinositides and release of (3H)arachidonic acid from phospholipids in pheochromocytoma PC12 cells. Formation of (3H)inositol phosphates is detected within 1 min of incubation even with concentrations as low as 0.3 ng/ml (90 pm) MTX, whereas release of (3H)arachidonic acid is not detected until 20 min even with concentrations as high as 1 ng/ml (300 pm) MTX. Stimulation of arachidonic acid release can be detected at 0.03 ng/ml (9 pm) MTX, whereas 0.1 ng/ml (30 pm) MTX is the threshold for detection of phosphoinositide breakdown. Organic and inorganic calcium channel blockers, except Cd2+ and a high concentration of Mn2+, have no effect on MTX-elicited phosphoinositide breakdown, whereas inorganic blockers (e.g., Co2+, Mn2+, Cd2+), but not organic blockers (nifedipine, verapamil, diltiazem), inhibit MTX-stimulated arachidonic acid release. All calcium channel blockers, however, inhibited MTX-elicited influx of 45Ca2+ and the MTX-elicited increase in internal Ca2+ measured with fura-2 was markedly reduced by nifedipine. MTX-elicited phosphoinositide breakdown and arachidonic acid release are abolished or reduced, respectively, in the absence of extracellular calcium plus chelating agent. The calcium ionophore A23187 has little or no effect alone but, in combination with MTX, A23187 inhibits MTX-elicited phosphoinositide breakdown and enhances arachidonic acid release, the latter even in the absence of extracellular calcium. The results suggest that different sites and/or mechanisms are involved in stimulation of calcium influx, breakdown of phosphoinositides, and release of arachidonic acid by MTX.

Choi, O.H.; Padgett, W.L.; Nishizawa, Y.; Gusovsky, F.; Yasumoto, T.; Daly, J.W. (National Institute of Diabetes, Digestive and Kidney Diseases, Bethesda, MD (USA))

1990-02-01

213

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

214

Effect of arachidonic acid, fatty acids, prostaglandins, and leukotrienes on volume regulation in Ehrlich ascites tumor cells  

Microsoft Academic Search

Summary Arachidonic acid inhibits the cell shrinkage observed in Ehrlich ascites tumor cells during regulatory volume decrease (RVD) or after addition of the Ca ionophore A23187 plus Ca. In Na-containing media, arachidonic acid increases cellular Na uptake under isotonic as well as under hypotonic conditions. Arachidonic acid also inhibits KCl and water loss following swelling in Na-free, hypotonic media even

Ian Henry Lambert

1987-01-01

215

An evaluation of tympanometric estimates of ear canal volume.  

PubMed

The accuracy of tympanometric estimates of ear canal volume was evaluated by testing the following two assumptions on which the procedure is based: (a) ear canal volume does not change when ear canal pressure is varied, and (b) an ear canal pressure of 200 daPa drives the impedance of the middle ear transmission system to infinity so the immittance measured at 200 daPa can be attributed to the ear canal volume alone. The first assumption was tested by measuring the changes in ear canal volume in eight normal subjects for ear canal pressures between +/- 400 daPa using a manometric procedure based on Boyle's gas law. The data did not support the first assumption. Ear canal volume changed by a mean of .113 ml over the +/- 400 daPa pressure range with slightly larger volume changes occurring for negative ear canal pressures than for positive ear canal pressures. Most of the volume change was attributed to movement of the probe and to movement of the cartilaginous walls of the ear canal. The second assumption was tested by comparing estimates of ear canal volume from susceptance tympanograms with a direct measurement of ear canal volume adjusted for changes in volume due to changes in ear canal pressure between +/- 400 daPa. These data failed to support the second assumption. All tympanometric estimates of ear canal volume were larger than the measured volumes. The largest error (39%) occurred for an ear canal pressure of 200 daPa at 220 Hz, whereas the smallest error (10%) occurred for an ear canal pressure of -400 daPa at 660 Hz. This latter susceptance value (-400 daPa at 660 Hz) divided by three is suggested to correct the 220-Hz tympanogram to the plane of the tympanic membrane. Finally, the effects of errors in estimating ear canal volume on static immittance and on tympanometry are discussed. PMID:7329051

Shanks, J E; Lilly, D J

1981-12-01

216

Relationship between the incidences of ear and spikelet infection of Fusarium ear blight in wheat  

Microsoft Academic Search

There is a urgent need to develop a rational strategy for managing Fusarium ear blight in order to reduce current reliance on routine fungicide applications, based on an objective assessment of disease risks. One of important components for such a management strategy is a fast, easy, accurate and reliable method for disease assessment. The relationship between incidence of Fusarium ear

X.-m. Xu; D. W. Parry; S. G. Edwards; B. M. Cooke; F. M. Doohan; A. Maanen; J. M. Brennan; S. Monaghan; A. Moretti; G. Tocco; G. Mule; L. Hornok; G. Giczey; J. Tatnell; P. Nicholson; A. Ritieni

2004-01-01

217

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

218

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

219

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

220

Ear Acupuncture in European Traditional Medicine  

PubMed Central

Auricular acupuncture is a diagnostic and treatment system based on normalizing the body's dysfunction through stimulation of definite points on the ear. Rudimentary forms of acupuncture which probably arose during the Stone Age have survived in many parts of the world right down to present day. It was used in the ancient Egypt, Rome, Greece and all the Mediterranean area. It is a microacupuncture technique similar to reflexology, and was first described in France in 1950 by Paul Nogier who is considered the Father of modern ear acupuncture. It was speculated that the technique works because groups of pluripotent cells contain information from the whole organism and create regional organization centers representing different parts of the body. Nevertheless stimulation of a reflex point in the ear seems relieve symptoms of distant pathologies. Modern research is confirming the efficacy of ear acupuncture for analgesia and anxiety related disease, while tobacco dependence and other substance abuse still need confirmation. Actually main methodological problems with auricular acupuncture are that exist too many maps with little agreement regarding point location in the ear, and that the correspondence or reflex systems does not correlated with modern knowledge of anatomy and physiology.

Firenzuoli, Fabio

2007-01-01

221

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

222

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

223

Intestinal vasodilation by epoxyeicosatrienoic acids: arachidonic acid metabolites produced by a cytochrome P450 monooxygenase.  

PubMed

Purified synthetic products from the cytochrome P450 pathway of arachidonate metabolism were applied to the intestinal serosa. Arteriolar blood flow was calculated using video microscopy. After a steady-state baseline, a bolus containing 10-60 micrograms 14,15-epoxyeicosatrienoic acid/ml (14,15-EET) had no detectable effect on blood flow. However, 25 +/- 3 micrograms 11,12-EET/ml and 36 +/- 2 micrograms 8,9-EET/ml caused increases (134 +/- 8% and 127 +/- 6%) that were similar to those elicited by 8 +/- 2 micrograms adenosine/ml (138 +/- 12%). Furthermore, the increases (275 +/- 38%) produced by 32 +/- 6 micrograms 5,6-EET/ml exceeded those elicited (160 +/- 10%) by a similar concentration (27 +/- 3 micrograms/ml) of adenosine. Thus, a structure-activity relationship is suggested. Nevertheless, these values probably underestimate the potency of the EETs because the vasoactivity was reduced by contact with water. The activity of the cyclooxygenase pathway seemed to limit the formation of vasoactive quantities of EETs, or other nonprostanoids, from exogenous arachidonate in the serosa but not the mucosa. A bolus (1.3 +/- 0.2 mg/ml) or continuous application (122 +/- 45 micrograms/ml) of arachidonate caused blood flow increases (236 +/- 14% or 229 +/- 27%) that were almost eliminated (129 +/- 5% or 121 +/- 9%) by a cyclooxygenase inhibitor; the residual response was abolished by a cytochrome P450 inhibitor. However, cytochrome P450 inhibitors alone did not attenuate the arachidonate response. In contrast, a continuous application of 194 micrograms arachidonate/ml to the mucosa caused a markedly smaller blood flow increase (119 +/- 8%) and cyclooxygenase inhibitors potentiated (132 +/- 8%), rather than reduced, this response. We conclude that EETs are a labile class of vasodilators with a potency comparable to adenosine in the intestinal microcirculation. Indirect evidence suggests regional differences in the formation of vasoactive quantities of arachidonate metabolites within the intestinal wall. PMID:3105909

Proctor, K G; Falck, J R; Capdevila, J

1987-01-01

224

Arachidonic Acid Metabolism in Polymorphonuclear Leukocytes: Effects of Ionophore A23187  

Microsoft Academic Search

Addition of arachidonic acid and the divalent cation ionophore A23187 to a suspension of human peripheral blood polymorphonuclear leukocytes led to the formation of (5S)-hydroxy-6,8,11,14-icosatetraenoic acid, (15S)-hydroxy-5,8,11,13-icosatetraenoic acid, and (5S, 12R)-dihydroxy-6,8,10,14-icosatetraenoic acid. A method based on high-pressure liquid chromatography has been developed for assay of these metabolites. The addition of arachidonic acid to human polymorphonuclear leukocytes always resulted in formation

Pierre Borgeat; Bengt Samuelsson

1979-01-01

225

Inhibition of the liberation of arachidonic acid by cadmium ions in rabbit alveolar macrophages  

Microsoft Academic Search

The effects of CdCl2 on the liberation of arachidonic acid (20?4) from membrane phospholipids of A23187-stimulated rabbit alveolar macrophages\\u000a and on the activity of phospholipase A2 (PLA2) in a cytosolic fraction were studied. Alveolar macrophages were prelabeled with [3H]arachidonic acid (20?4) and then treated with A23187. This treatment resulted in a remarkable increase in the liberation\\u000a of [3H]20?4 from their

Naomi Kudo; Yasuhito Nakagawa; Keizo Waku

1992-01-01

226

Arachidonic acid activation of a new family of K+ channels in cultured rat neuronal cells.  

PubMed Central

1. The presence and properties of K+ channels activated by arachidonic acid were studied in neuronal cells cultured from the mesencephalic and hypothalamic areas of rat brain. 2. Arachidonic acid produced a concentration-dependent (5-50 microM) and reversible activation of whole-cell currents. 3. In excised membrane patches, arachidonic acid applied to the cytoplasmic or extracellular side of the membrane caused opening of three types of channels whose current-voltage relationships were slightly outwardly rectifying, inwardly rectifying and linear, and whose single channel slope conductances at +60 mV were 143, 45 and 52 pS, respectively. 4. All three currents were K+ selective and blocked by 2 mM Ba2+ but not by other K+ channel blockers such as tetraethylammonium chloride, 4-aminopyridine and quinidine. The outwardly and inwardly rectifying currents were slightly voltage dependent with higher channel activity at more depolarized potentials. 5. Arachidonic acid activated the K+ channels in cells treated with cyclo-oxygenase and lipoxygenase inhibitors (indomethacin and nordihydroguaiaretic acid), indicating that arachidonic acid itself can directly activate the channels. Alcohol and methyl ester derivatives of arachidonic acid failed to activate the K+ channels, indicating that the charged carboxyl group is important for activation. 6. Certain unsaturated fatty acids (linoleic, linolenic and docosahexaenoic acids), but not saturated fatty acids (myristic, palmitic, stearic acids), also reversibly activated all three types of K+ channel. 7. All three K+ channels were activated by pressure applied to the membrane (i.e. channels were stretch sensitive) with a half-maximal pressure of approximately 18 mmHg. The K+ channels were not blocked by 100 microM GdCl3. 8. A decrease in intracellular pH (over the range 5.6-7.2) caused a reversible, pH-dependent increase in channel activity whether the channel was initially activated by arachidonic acid or stretch. 9. Glutamate, a neurotransmitter reported to generate arachidonic acid in striatal neurons, did not cause activation of the K+ channels when applied extracellularly in cell-attached patches. 10. It is suggested that the K+ channels described here belong to a distinct family of ion channels that are activated by either fatty acids or membrane stretch. Although the physiological roles of these K+ channels are not yet known, they may be involved in cellular processes such as cell volume regulation and ischaemia-induced elevation of K+ loss. Images Figure 1

Kim, D; Sladek, C D; Aguado-Velasco, C; Mathiasen, J R

1995-01-01

227

Adipose tissue arachidonic acid content is associated with the expression of 5-lipoxygenase in atherosclerotic plaques  

PubMed Central

Background The content of arachidonic acid in adipose tissue is positively associated with the risk of myocardial infarction, whereas the content of eicosapentaenoic acid in adipose tissue has been reported to be negatively associated with the risk of myocardial infarction. Both arachidonic acid and eicosapentaenoic acid are substrates for the synthesis of pro-inflammatory leukotrienes and leukotrienes derived from eicosapentaenoic acid are generally much less potent. In this study we hypothesized that a high content of arachidonic acid in adipose tissue would reflect a high formation of arachidonic acid derived leukotrienes and a high expression of 5-lipoxygenase in atherosclerotic plaques. Likewise, we hypothesized that a high content of eicosapentaenoic acid in adipose tissue would reflect a low formation of arachidonic acid derived leukotrienes and a low expression of 5-lipoxygenase in plaques. Methods In a cross sectional study we included 45 consecutive subjects undergoing femoral thrombendarterectomy. The expression of 5-lipoxygenase in plaques was assessed by a semi-automated image analysis computer programme after immunohistochemical staining with mono-clonal 5-lipoxygenase antibodies. Leukotriene B4 and cysteinyl leukotriene formation from stimulated femoral artery plaques was quantified using ELISA methods. The fatty acid content of adipose tissue biopsies from the thigh was analyzed using gas chromatography. Associations between variables were assessed by Pearson correlations and were further explored in a multivariable linear regression model adjusting for potential confounders. Results A high content of arachidonic acid in adipose tissue was associated with a higher expression of 5-lipoxygenase in plaques (r?=?0.32, p?=?0.03), but no significant associations with leukotriene B4 (r?=?0.22, p?=?0.14) and cysteinyl leukotriene (r?=??0.11, p?=?0.46) formation was seen. No significant associations were found between the content of eicosapentaenoic acid in adipose tissue and 5-lipoxygenase expression or leukotriene formation in plaque. Conclusions Adipose tissue arachidonic acid contents correlated positively with the expression of 5-lipoxygenase in plaques. This association might represent a causal link between adipose tissue arachidonic acid and the risk of myocardial infarction but confirmatory studies are needed.

2013-01-01

228

Local inner-ear drug delivery and pharmacokinetics.  

PubMed

Several drugs that are applied directly to the inner ear are in widespread clinical use for the treatment of inner-ear disorders. Many new substances and drug delivery systems specific to the inner ear are under development and in some cases are being evaluated in animal experiments and in clinical studies. However, the pharmacokinetics of drugs in the inner ear is not well defined and the field is plagued by technical problems in obtaining pure samples of the inner-ear fluids for analysis. Nevertheless, a basic understanding of the mechanisms of drug dispersal in the inner ear has emerged, which facilitates the design and interpretation of future pharmacokinetic studies. PMID:16214674

Salt, Alec N; Plontke, Stefan K R

2005-10-01

229

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

230

[The tempestuous history of middle ear operation].  

PubMed

The paper is a review of primary and secondary historical and scientific literature concerning the surgical treatment of the middle ear diseases. The development of mastoid surgery can be traced through the past 4 centuries. Once used as a means of evacuating a postauricular abscess, it has evolved to become a method for gaining entry into the middle ear to control acute and chronic ear diseases, or for treatment of otogenic complications. Earlier works led the way to the postauricular "Wilde incision", which gave rise to Schwartze mastoidectomy. Oscar Wilde's ultimate demise from an otogenic meningitis appears all the more ironic when one considers the role his father, Sir William Wilde, played as one of the founding fathers of modern otology. The death of baron von Berger after mastoidectomy performed for treatment of tinnitus and hypacusis, stopped the further development of surgical procedures for about hundred years. The Joseph Toynbee's "Diseases of the ear" was the first work about ear diseases on a pathologic anatomical base, and fundamental for otology of the German speaking countries in the nineteenth and early twentieth centuries. Otology was emerging as a specific specialty. Von Tröltsch was the first surgeon, who proposed the antral opening through the external ear canal. When Schwartze and his assistant, Eysell, published their paper: "On the Artificial Opening of the Mastoid Air Cells," a century or so had passed since the few previous attempts to remove the tegmen of the mastoid had been reported. One of the greatest otologists of the 19th century was Adam Politzer, His influence on the 50 years of otology has never been equaled. It is in his honor that the International Society of Otology bears his name. PMID:18837236

Betlejewski, Stanis?aw; Betlejewski, Andrzej

2008-01-01

231

High intensity anthropogenic sound damages fish ears  

NASA Astrophysics Data System (ADS)

Marine petroleum exploration involves the repetitive use of high-energy noise sources, air-guns, that produce a short, sharp, low-frequency sound. Despite reports of behavioral responses of fishes and marine mammals to such noise, it is not known whether exposure to air-guns has the potential to damage the ears of aquatic vertebrates. It is shown here that the ears of fish exposed to an operating air-gun sustained extensive damage to their sensory epithelia that was apparent as ablated hair cells. The damage was regionally severe, with no evidence of repair or replacement of damaged sensory cells up to 58 days after air-gun exposure.

McCauley, Robert D.; Fewtrell, Jane; Popper, Arthur N.

2003-01-01

232

2009 Meeting Materials of the Ear, Nose, and Throat Devices ...  

Center for Biologics Evaluation and Research (CBER)

... Roster of the Ear, Nose, and Throat Devices Panel. ? -. Resources for You. ... 2009 Meeting Materials of the Ear, Nose, and Throat Devices Panel. -. ... More results from www.fda.gov/advisorycommittees/committeesmeetingmaterials/medicaldevices

233

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

234

Involvement of Arachidonic Acid in Nonimmunologic Production of Superoxide in Mast Cells  

Microsoft Academic Search

Background: A number of different molecules are known to be involved in the signal pathway to release histamine from mast cells, among which arachidonic acid (AA) is one of the key mediators. On the other hand, we found that the application of compound 48\\/80, a typical histamine liberator, generated superoxide in mast cells. In the present study, we investigated the

Masakiyo Sakaguchi; Nobuyuki Fukuishi; Kazuyo Teramoto; Masahiro Miyazaki; Nam-ho Huh; Masayoshi Namba; Masaaki Akagi

2003-01-01

235

Mechanisms of reflex bradycardia and hypotension by metabolites of arachidonic acid in the cat.  

PubMed Central

In the cat, intravenous injections of arachidonic acid or prostaglandin (PG)F2 alpha caused significant reductions in mean arterial pressure and heart rate which were eliminated or significantly lessened, respectively, by previous administration of indomethacin. The bradycardia to intravenous prostacyclin (PGI2) was unaffected by indomethacin. In cats with bilateral ligation of the carotid arteries to eliminate competition between systemic baroreflexes and cardiopulmonary reflexes, PGI2, PGF2 alpha and arachidonic acid caused significantly greater hypotension and bradycardia than in cats with intact carotid baroreflexes. The bradycardia to PGI2, PGF2 alpha and arachidonic acid was eliminated by bilateral vagal section or atropine. PGE1, PGE2 and nitroprusside caused dose-related falls in mean arterial pressure and a small tachycardia. In a small group of cats (7 of 67) nitroprusside also caused a reduction in heart rate which was eliminated by indomethacin. We conclude that the reflex bradycardia to PGF2 alpha, like that to arachidonic acid is, at least in part, the result of the stimulation of synthesis of another prostaglandin, most likely PGI2.

Hintze, T. H.; Kaley, G.; Panzenbeck, M. J.

1984-01-01

236

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

237

Dexamethasone blocks arachidonate biosynthesis in isolated hepatocytes and cultured hepatoma cells  

SciTech Connect

The effect of dexamethasone on the incorporation and conversion of (1-14C)eicosa-8,11,14-trienoic acid to arachidonic acid in isolated hepatocytes and in hepatoma tissue culture (HTC) cells was studied. In both kinds of cells, no changes in the exogenous acid incorporation were found when the hormone was added to the incubation media at 0.1 or 0.2 mM concentration, while the biosynthesis of arachidonic acid was significantly depressed. The effect on the biosynthesis was faster in isolated normal liver cells (60 min) than in tumoral cells (120 min) and reached an inhibition of ca. 50% after 3 hr of treatment. The addition of cycloheximide (10(-6) M) also caused a marked decrease in the biosynthesis of this polyunsaturated fatty acid, but when dexamethasone was added to the media simultaneously with cycloheximide, a synergistic action was not observed. The results obtained show that protein synthesis would be involved in the modulation of the biosynthesis of arachidonic acid by glucocorticoids. The changes in the delta 5 desaturation of labeled 20:3 omega 6 to arachidonic acid correlated with changes in the fatty acid composition in isolated cells.

Marra, C.A.; de Alaniz, M.J.; Brenner, R.R.

1986-03-01

238

Identification of an Arachidonic Acid-Producing Bacterium and Description of Kineococcus arachidonicus sp. nov.  

SciTech Connect

The identification of bacterial with the ability to produce polyunsaturated fatty acids as been limited almost exclusively to gram-negative, psychrophilic, marine microorganisms. Here we describe a new gram-type-positive bactgerium, strain SRS30216T, that produces the polyunsaturated fatty acid, arachidonic acid, and is neither psychrophilic nor a marine isolate.

Fliermans, C.B.

2001-05-15

239

Arachidonic acid synthesis and lipid metabolism in retinoic acid-differentiated neuroblastoma cells  

Microsoft Academic Search

SK-N-BE cells were differentiated (D) to neurons with retinoic acid. Total n - 6 polyunsaturated fatty acids (PUFA), especially arachidonic acid (AA), were increased in D versus ND cells. AA synthesis from linoleic acid (LA) and phospholipid (PL) synthesis from glycerol were initially elevated, whereas both processes were reduced approaching differentiation. At this stage, the incorporation of glycerol in triglycerides

Anna Petroni; Milena Blasevich; Patrizia La Spada; Nadia Papini; Claudio Galli

1996-01-01

240

Euglena gracilis: A Novel Lipid Energy Reserve and Arachidonic Acid Enrichment during Fasting  

Microsoft Academic Search

In Euglena gracilis grown in the dark, wax esters, consisting of a combination of medium-chain fatty acids and alcohols that contain both odd and even numbers of carbon atoms, appear to be a reservoir for metabolic energy. When the organisms are fasted, their pellicular membrane systems become quite rich in long-chain polyenoic acids, mostly of the arachidonic acid family.

Abraham Rosenberg

1967-01-01

241

The CYP P450 Arachidonic Acid Monooxygenases: From Cell Signaling to Blood Pressure Regulation  

Microsoft Academic Search

The studies of the cytochrome P450 (P450) arachidonic acid (AA) monooxygenase, now established as a major pathway for the bioactivation of AA, have uncovered new and important functional roles for this enzyme system in cell and organ physiology, and in the metabolism of endogenous substrate. Past and present advances in P450 biochemistry and molecular biology are beginning to provide a

Jorge H. Capdevila; John R. Falck

2001-01-01

242

Arachidonic acid and prostacyclin signaling promote adipose tissue development: a human health concern?  

Microsoft Academic Search

High fat intake is associated with fat mass gain through fatty acid activation of peroxisome proliferator-acti- vated receptorsand ? , which promote adipogenesis. We show herein that, compared to a combination of specific ag- onists to both receptors or to saturated, monounsaturated, and ? -3 polyunsaturated fatty acids, arachidonic acid (C20:4, ? -6) promoted substantially the differentiation of clonal preadipocytes.

Florence Massiera; Perla Saint-Marc; Josiane Seydoux; Takahiko Murata; Takuya Kobayashi; Shuh Narumiya; Philippe Guesnet; Ez-Zoubir Amri; Raymond Negrel; Gérard Ailhaud

2003-01-01

243

Molecular-dynamics simulation of dioxygen egress from 12/15-lipoxygenase-arachidonic acid complex.  

PubMed

Extensive random-acceleration molecular-dynamics (RAMD) simulations of the egress of dioxygen (O?) from a model of rabbit 12/15-lipoxygenase-arachidonic acid complex disclosed several exit portals in addition to those previously described from implicit ligand sampling calculations and limited MD simulations. PMID:22700222

Pietra, Francesco

2012-06-01

244

Activated rat neutrophils. Correlation of arachidonate products with enzyme secretion but not with O(2)- generation.  

PubMed Central

Functional responses (enzyme secretion and generation of O2-) have been studied in rat neutrophils with the use of a variety of different agonists which vary in their ability to activate neutrophils. Concomitantly, the authors have analyzed the cells for production of cyclooxygenase (PGE2, PGF2 alpha, and TXB2) and lipoxygenase (monoHETEs and LTB4) products in order to determine whether there is a correlation between functional responses and arachidonate products in stimulated neutrophils. The studies indicate that enzyme secretion is closely correlated with generation of arachidonate (cyclooxygenase as well as lipoxygenase) products. These responses are dependent on the dose of agonist employed, but there does not appear to be a unique pattern of arachidonate products that can be attributed to a specific agonist. With respect to monohydroxyeicosatetraenoic acid (monoHETE) generation, we demonstrate that stimulated rat neutrophils selectively produce 5-HETE, to the virtual exclusion of 12-HETE and 15-HETE. The production of O2- from stimulated rat neutrophils is correlated neither with enzyme secretion nor with the generation of arachidonate products. These studies suggest that enzyme secretion and O2- generation are mediated by two fundamentally different intracellular pathways, even though these functional responses probably derive from common agonist-receptor interactions on the plasma membrane.

Ward, P. A.; Sulavik, M. C.; Johnson, K. J.

1985-01-01

245

In vivo platelet activation with in vitro hyperaggregability to arachidonic acid in renal allograft recipients  

Microsoft Academic Search

In vivo platelet activation with in vitro hyperaggregability to arachidonic acid in renal allograft recipients. Renal allograft recipients were investigated to determine the extent and possible nature of in vivo platelet activation. In 92 allografted patients stable for more than 4 months' duration, intraplatelet serotonin in circulating platelets was depleted significantly. In a further 16 patients studied serially for 12

Geoffrey Frampton; Anwar Parbtani; Donatella Marchesi; Peter Duffus; Manuela Livio; Giuseppe Remuzzi; John Stewart Cameron

1983-01-01

246

Inhibition of the arachidonic acid metabolism blocks endothelial cell migration and induces apoptosis  

Microsoft Academic Search

Summary Previous studies have demonstrated that inhibitors of the arachidonic acid metabolism block migration and sensitise human glioma cells to treatment inducing apoptosis. This paradigm may provide a new concept for anti-invasive treatment strategies targeting invasive glioma cells. However, the effect of such treatment on other cellular elements in glial tumours such as endothelial cells is unknown. In this study

J. Jantke; M. Ladehoff; F. Kürzel; S. Zapf; E. Kim; A. Giese

2004-01-01

247

Antiplatelet effect of green tea catechins: a possible mechanism through arachidonic acid pathway  

Microsoft Academic Search

We have previously reported that green tea catechins (GTC) showed an antithrombotic activity, which might be due to antiplatelet effect rather than anticoagulation. The present study was performed to investigate the effect of GTC on the arachidonic acid (AA) metabolism in order to elucidate a possible antiplatelet mechanism. GTC inhibited the collagen-, AA- and U46619-induced rabbit platelet aggregation in vitro

Dong-Ju Son; Mi-Ra Cho; Yong-Ri Jin; Soo-Yeon Kim; Young-Hyun Park; Soo-Hwan Lee; Satoshi Akiba; Takashi Sato; Yeo-Pyo Yun

2004-01-01

248

Role of CYP450 metabolites of arachidonic acid during pregnancy induced hypertension in rats  

Microsoft Academic Search

We have reported that chronic reductions in uterine perfusion pressure in pregnant rats lead to a hypertensive state closely resembles preeclampsia in women. The increased arterial pressure in these rats is associated with renal vasoconstriction, proteinuria and endothelial dysfunction. Alterations in renal metabolism of CYP450 metabolites of arachidonic have been reported in different models of hypertension and in women with

Maria T. Llinas; Barbara T. Alexander; Maria F. Capparelli; Mairead A. Carroll; Joey P. Granger

2002-01-01

249

Imaging Neuroinflammation in Alzheimer's Disease with Radiolabeled Arachidonic Acid and PET  

Microsoft Academic Search

Incorporation coefficients (K*) of arachidonic acid (AA) in the brain are increased in a rat model of neuroinflammation, as are other markers of AA metabolism. Data also indicate that neuro- inflammation contributes to Alzheimer's disease (AD). On the ba- sis of these observations, K* for AA was hypothesized to be elevated in patients with AD. Methods: A total of 8

Giuseppe Esposito; Giampiero Giovacchini; Jeih-San Liow; Abesh K. Bhattacharjee; Dede Greenstein; Mark Schapiro; Mark Hallett; Peter Herscovitch; William C. Eckelman; Richard E. Carson; Stanley I. Rapoport

2008-01-01

250

Glucocorticoids Fail to Inhibit Arachidonic Acid Metabolism Stimulated by Hydrogen Peroxide in the Alveolar Macrophage  

Microsoft Academic Search

We have previously demonstrated that the biologically important oxidant hydrogen per- oxide (H202) triggers release and metabolism of arachidonic acid (AA) in the alveolar macrophage (AM). In this study, we evaluated the ability of glucocorticoids to inhibit rat AM AA metabolism stimulated by H2O2, as compared to the particulate zymosan. Meth- ybprednisobone and other glucocorticoids failed to significantly inhibit release

Peter H. S. Sporn; Teresa M. Murphy; Marc Peters-Golden

251

Preparation of cis,cis,cis -5,8,11-eicosatrienoic acid from arachidonic acid  

Microsoft Academic Search

Arachidonic acid was reduced by hydrazine to yield isomeric eicosatrienoic acids with other products. Methylcis,cis,cis-5,8,11-eicosatrienoate was isolated from the products by silver ion chromatography and preparative gas liquid chromatography\\u000a in 8% yield. The structure was confirmed by spectral studies and oxidative degradation.

Amitabha Ghosh; Malati Koley; J. Dutta

1982-01-01

252

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...

253

Modulation of arachidonic acid metabolism by orally administered morniflumate in man  

Microsoft Academic Search

Unlike other classic NSAIDs, some fenamates given at therapeutic concentrations, have been shown to inhibit, bothin vitro andin vivo, the 5-lipoxygenase pathway of arachidonic acid cascade as well as the synthesis of cyclooxygenase products. This dual inhibitory property might represent an improvement in anti-inflammatory therapy. The aim of this work was to characterize the effect of morniflumate, admistered at therapeutic

M. Civelli; T. Vigano; D. Acerbi; P. Caruso; M. Giossi; S. Bongrani; G. C. Folco

1991-01-01

254

Necturus gallbladder epithelial cell volume regulation and inhibitors of arachidonic acid metabolism  

Microsoft Academic Search

Inhibition of the metabolism of arachidonic acid by the epoxygenase (cytochrome P-450) pathway with the inhibitor ketoconazole results in excessive cell swelling upon exposure to hyposmolality instead of the rapid and complete regulatory volume decrease (RVD) normally observed. NaCl entry from bathing solutions to cell interior was shown to cause this swelling, with Na influx occurring across the basolateral membrane

Ulrich Kersting; Sophon Napathorn; Kenneth R. Spring

1993-01-01

255

Psychosocial Effects of Otoplasty in Children with Prominent Ears  

Microsoft Academic Search

This study aimed to investigate changes experienced by children during the pre- and postoperative periods of prominent ear\\u000a corrective surgery. A total of 30 patients with prominent ears, sometimes called “lop ears” or “cup ears,” ranging in age\\u000a from 6 to 14 years were consecutively enrolled in this study. Half of the patients (n = 15, 50%) were male. The inclusion criteria

J. Á. Lourenço Gasques; J. M. Pereira de Godoy; E. M. T. Navarro Cruz

2008-01-01

256

Structures that contribute to middle-ear admittance in chinchilla  

Microsoft Academic Search

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\\u000a chinchilla’s middle-ear air spaces have a large effect on the low-frequency compliance of the middle ear, and removing the\\u000a influences of these spaces reveals a highly admittant tympanic membrane and ossicular chain. Measurements

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

2006-01-01

257

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

258

Groovy flow patterns in the fish ear  

Microsoft Academic Search

The dense, bony otoliths contained in the fish ear oscillate with respect to their surrounding tissue and endolymph in the presence of sound waves. How an otolith actually transduces this acoustically induced fluid motion into the hair cell displacements that the fish ``hears'' is not fully understood, however. The fluid flow created by the oscillation of the irregularly shaped otolith

Charlotte W. Kotas; Peter H. Rogers; Minami Yoda

2007-01-01

259

Diving injuries to the inner ear  

Microsoft Academic Search

Two skin divers and 7 SCUBA divers, all men, aged 21–33 years, are presented. The injury occurred at shallow depths and difficulties with pressure equilibration to the ears were a common complaint. Vertigo and hearing losses. When a perilymph fistula is suspected and decompression sickness can be in the round, the other in the oval window. The latter patient also

O. I. Molvær; E. Natrud; S. Eidsvik

1978-01-01

260

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

261

Targeted Therapy of the Inner Ear  

Microsoft Academic Search

Background: There is experimental evidence that targeted delivery of steroids to the inner ear can protect hearing during cochlear implant surgery. The best protection appears to be achieved through pre-treatment of the cochlea, but the time period required for treatment is long compared with the duration of surgery, and needs further optimization. The stability of hearing thresholds is determined over

Sangeeta Maini; Halina Lisnichuk; Hayden Eastwood; Darren Pinder; David James; Rachael T. Richardson; Andrew Chang; Tim Connolly; David Sly; Gordana Kel; Stephen J. O’Leary

2009-01-01

262

Collagen types in the middle ear mucosa  

Microsoft Academic Search

The distribution of various collagen types — in particular that of type 11 as the major collagen in cartilage — in normal auricular structures is discussed with reference to a 1994 report by Ovesen describing the presence of collagen type II in normal middle ear mucosa. In contrast to this report, no collagen type 11 is normally found in the

A. G. Nerlich

1995-01-01

263

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

264

A review of microvascular ear replantation.  

PubMed

Microvascular ear replantation is a significant challenge because of the small size of the vessels and the fact that traumatic amputations are frequently avulsed. The zone of trauma is therefore extended and the primary repair of the injured vessel is rendered unlikely. The purpose of this study is to review the literature of ear replantation. A review of the relevant literature that has been published since 1980 revealed 47 cases reported in 37 publications. We present 5 cases from our own experience and analyze a total 52 cases of microvascular ear replantation. The patient's age, sex, degree of amputation, cause of injury, ischemic time, method of arterial and venous anastomosis, complications, any additional outflow used, postoperative medications, the requirement for transfusions, and the number of hospital admission days are described. Successful microvascular ear replantations require anastomosis of the vessels if possible. Rather than a vein graft, primary repair of the vessels, or at least pedicled repair of the artery, should be considered to ensure flap survival. In addition, vein repair should be considered if possible to ensure the secure drainage of blood from the replant. With secure circulation, the replant can survive, resulting in a very satisfactory outcome. PMID:23277409

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

2012-12-31

265

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

266

Ca2+ Signaling in the Inner Ear  

NSDL National Science Digital Library

The inner ear contains delicate sensory receptors that have adapted to detect the minutest mechanical disturbances. Ca2+ ions are implicated in all steps of the transduction process, as well as in its regulation by an impressive ensemble of finely tuned feedback control mechanisms. Recent studies have unveiled some of the key players, but things do not sound quite right yet.

2007-04-01

267

Mutations affecting development of the zebrafish ear  

Microsoft Academic Search

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

Jarema Malicki; Alexander F. Schier; Lilianna Solnica-Krezel; Derek L. Stemple; Stephan C. F. Neuhauss; Didier Y. R. Stainier; Salim Abdelilah; Zehava Rangini; Fried Zwartkruis; Wolfgang Driever

268

The Croton oil ear test revisited  

Microsoft Academic Search

measurement the ear plugs were homogenized in physiological saline containing 0.1% of hexadecyltrimethylammonium bromide. The post 15,000 g supernatants of the homogenates (which contained more than 95% of the PA) were used for the assay [5]. PA units are expressed as nmoles of tetraguaiacol\\/min at 25~ Results and discussion

A. Tubaro; P. Dri; G. Delbello; C. Zilli; R. Della Loggia

1986-01-01

269

Anatomy of the Rat Middle Ear  

Microsoft Academic Search

The rat is of value in otological research for many reasons. For instance, the middle ear structures are easily approachable. Recently a couple of studies in the rat have been published concerning the healing pattern of tympanic membrane perforations and mucosal changes following Eustachian tube blockade including the otitis media with effusion. Essential for the evaluation of these studies is

Sten Hellström; Bengt Salén; Lars-Eric Stenfors

1982-01-01

270

Finite element analysis of middle ear mechanics  

Microsoft Academic Search

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

James Peter Tuck-Lee

2007-01-01

271

Esteem 2 Middle Ear Implant: Our Experience  

Microsoft Academic Search

Introduction: The Esteem is a totally implantable hearing system that uses piezoelectric technology. It is indicated in case of moderate to severe stable sensorineural hearing loss with a minimum discrimination score of 60% and a middle ear which is anatomically and functionally intact. Its two components (sensor and driver) are positioned and fixed in the mastoid cavity and coupled respectively

J. M. Gerard; M. P. Thill; G. Chantrain; M. Gersdorff; N. Deggouj

2012-01-01

272

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

273

Experimental lipidosis of the inner ear  

Microsoft Academic Search

Summary  Chronic administration of so-called amphiphilic drugs induces an accumulation of lysosomes of different types containing phospholipids in the inner ear. The inclusions are regularly found in the inner hair cells of the organ of Corti, sometimes in supporting cells, whereas the outer hair cells remain almost unchanged. Several nerve fibres in the area of the inner pillar cells and to

E. Bichler; H. Spoendlin

1980-01-01

274

The fungal flora of zoo animals' ears.  

PubMed

The mycotic flora of the ears of zoo animals was investigated in a large zoological garden in Germany. Malassezia pachydermatis was isolated from the following animals: big ant-eater, brown bear, common wombat, Eurasian badger, Indian elephant, Mangaliza pig and wide-mouthed rhinoceros. Aspergillus and Penicillium species, yeasts and zygomycetes were also isolated from some animals. PMID:7935595

Kuttin, E S; Müller, J

275

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

MedlinePLUS

... is Pseudomonas and how can it affect me? Pseudomonas (sue-doh-MOH-nass) aeruginosa is a major cause of infections commonly known as “hot tub rash” and “swimmer’s ear.” This germ is ... (Pseudomonas dermatitis) > Itchy spots on the skin that become ...

276

Tumor Cell-derived 12(S)-Hydroxyeicosatetraenoic Acid Induces Microvascular Endothelial Cell Retraction  

Microsoft Academic Search

Our previous work demonstrated that the 12-1ipoxygenase metabolite of arachidonic acid, 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE) in- duced a nondestructive and reversible retraction of cultured endothelial cells. In the current study we tested the hypothesis that tumor cells pro- duce 12(S)-HETE during their interactions with endothelial cells which in turn induces endothelial cell retraction. Coincubation of Lewis lung car- cinoma cells or

Kenneth V. Honn; Dean G. Tang; Irma Grossi; Zofia M. Duniec; Jozsef Timar; Colette Renaud; Marie Leithauser; Ian Blair; Carl R. Johnson; Clement A. Diglio; Victoria A. Kimler; John D. Taylor; Lawrence J. Marnett

277

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

278

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

Code of Federal Regulations, 2010 CFR

... (a) Identification. An ear, nose, and throat bur is...that is intended for use in an ear, nose, and throat electric...incising or removing bone in the ear, nose, or throat area...notification procedures in subpart E of part 807 of this chapter subject...

2009-04-01

279

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

Code of Federal Regulations, 2010 CFR

... (a) Identification. An ear, nose, and throat bur is...that is intended for use in an ear, nose, and throat electric...incising or removing bone in the ear, nose, or throat area...notification procedures in subpart E of part 807 of this chapter subject...

2010-04-01

280

40 CFR 211.206-1 - Real ear method.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Real ear method. 211.206-1 Section 211...Protective Devices § 211.206-1 Real ear method. (a) The value of sound attenuation...Method for the Measurement of Real-Ear Protection of Hearing Protectors...

2013-07-01

281

Factors contributing to bone conduction: The outer ear  

Microsoft Academic Search

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

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

2003-01-01

282

Ear and kidney syndromes: Molecular versus clinical approach  

Microsoft Academic Search

Ear and kidney syndromes: Molecular versus clinical approach.The association between ear and kidney anomalies is not usually due to an insult to the embryo. In recent years, many essential development control genes that coordinate the assembly and function of kidney and ear have been discovered through the generation of animal mutants and have increased our understanding of the mechanisms of

HASSANE IZZEDINE; FREDERIC TANKERE; VINCENT LAUNAY-VACHER; GILBERT DERAY

2004-01-01

283

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

284

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

285

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

286

Sources of Variability in Reflectance Measurements on Normal Cadaver Ears  

Microsoft Academic Search

Objectives: The development of acoustic reflectance measurements may lead to noninvasive tests that provide information currently unavailable from standard audiometric testing. One factor limiting the development of these tests is that normal-hear- ing human ears show substantial intersubject vari- ations. This work examines intersubject variability that results from measurement location within the ear canal, estimates of ear-canal area, and varia-

Susan E. Voss; Nicholas J. Horton; Rebecca R. Woodbury; Kathryn N. Sheffield

2008-01-01

287

Connected component based technique for automatic ear detection  

Microsoft Academic Search

This paper presents an efficient technique for automatic ear detection from side face images. The proposed technique detects ear by exploiting its inherent structural details and is rotation, scale and shape invariant. It can detect ear without any training or assuming prior knowledge of the input image. The technique is based on connected component analysis of a graph constructed using

Surya Prakash; Umarani Jayaraman; Phalguni Gupta

2009-01-01

288

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

289

On hearing with more than one ear: lessons from evolution  

Microsoft Academic Search

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

Catherine E Carr; Jan W H Schnupp

2009-01-01

290

Two Ears are Better Than One: Sound Localization  

NSDL National Science Digital Library

This activity (9th activity on the page) about hearing demonstrates to learners the importance of having two ears. A blindfolded learner tries to identify the distance of another individual while listening for their name using one or both ears. This activity page includes a link to background information about the ear and hearing.

Chudler, Eric H.

2009-01-01

291

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

Code of Federal Regulations, 2013 CFR

...CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4140 Ear, nose, and throat bur. ...for use in an ear, nose, and throat electric or pneumatic surgical drill (§ 874.4250) for incising or removing bone...

2013-04-01

292

Identification of Novel Endogenous Cytochrome P450 Arachidonate Metabolites with High Affinity for Cannabinoid Receptors*  

PubMed Central

Arachidonic acid is an essential constituent of cell membranes that is esterified to the sn-2-position of glycerophospholipids and is released from selected lipid pools by phospholipase cleavage. The released arachidonic acid can be metabolized by three enzymatic pathways: the cyclooxygenase pathway forming prostaglandins and thromboxanes, the lipoxygenase pathway generating leukotrienes and lipoxins, and the cytochrome P450 (cP450) pathway producing epoxyeicosatrienoic acids and hydroxyeicosatetraenoic acids. The present study describes a novel group of cP450 epoxygenase-dependent metabolites of arachidonic acid, termed 2-epoxyeicosatrienoylglycerols (2-EG), including two regioisomers, 2-(11,12-epoxyeicosatrienoyl)glycerol (2-11,12-EG) and 2-(14,15-epoxyeicosatrienoyl)glycerol (2-14,15-EG), which are both produced in the kidney and spleen, whereas 2-11,12-EG is also detected in the brain. Both 2-11,12-EG and 2-14,15-EG activated the two cannabinoid (CB) receptor subtypes, CB1 and CB2, with high affinity and elicited biological responses in cultured cells expressing CB receptors and in intact animals. In contrast, the parental arachidonic acid and epoxyeicosatrienoic acids failed to activate CB1 or CB2 receptors. Thus, these cP450 epoxygenase-dependent metabolites are a novel class of endogenously produced, biologically active lipid mediators with the characteristics of endocannabinoids. This is the first evidence of a cytochrome P450-dependent arachidonate metabolite that can activate G-protein-coupled cell membrane receptors and suggests a functional link between the cytochrome P450 enzyme system and the endocannabinoid system.

Chen, Jian-Kang; Chen, Jianchun; Imig, John D.; Wei, Shouzuo; Hachey, David L.; Guthi, Jagadeesh Setti; Falck, John R.; Capdevila, Jorge H.; Harris, Raymond C.

2008-01-01

293

Localization of glyoxylic acid-induced histofluorescence in surgically isolated medial basal hypothalamus of the rat  

Microsoft Academic Search

Examination of glyoxylic acid-induced catecholamine histofluorescence in the hypothalamic median eminence of adult male rats revealed a linear pattern of fine varicosities coursing through the ependymal and fibrous zones, suggestive of juxtaposition to tanycytes. In order to determine the origin of these terminals, adult rats were subjected to complete isolation of the medial basal hypothalamus, using a small Halasz-Pupp knife.

Carol Turpen; John R. Sladek

1978-01-01

294

Ear piercing affects earprints: the role of ear piercing in human identification.  

PubMed

Previous research conducted into the use of the human ear in the field of forensic identification has focused upon the use of grids and manual methods to measure and catalogue the different anatomical features of the ear. To date, few have considered the importance of the presence of ear piercings and their possible role in human identification. This study aims to highlight the common distribution of piercings of both ears in both genders and to explore the effect of piercings on earprints. The presence of a piercing may, in part, help to explain why partial and not whole earprints are sometimes recovered from a scene of crime (suggesting that the offender's ears may be pierced). The presence of piercings through the tragus and the superior part of the helix are shown to be infrequent and thus may be used to assist the identification of a body, due to its relative rarity with respect to piercings found in other areas of the ear. PMID:15813550

Abbas, Ali; Rutty, Guy N

2005-03-01

295

Ear deformity in children following high ear-piercing: current practice, consent issues and legislation.  

PubMed

In this presentation we examine the practice of high ear-piercing in children, the issue of informed consent and current legislation. We sampled current practice and consent policy by visiting nine establishments in Sheffield providing this service. There were two high street department stores, two fashion accessory outlets and five body-piercing studios. Enquiries were made as to the technique used, knowledge of complications, customer counselling and consent policy. A photograph of an ear with a cosmetic deformity following high ear-piercing was shown and awareness of this possible outcome was noted. Two ear-piercing techniques were identified, either a spring-loaded gun firing a blunt stud or the use of a body-piercing needle. The fashion accessory outlets were prepared to pierce any part of the ear using a spring-loaded gun in children under 16 years of age. There was a general lack of knowledge about possible serious complications. Two of the body piercers would not perform high ear-piercing on clients under the age of 16 years. The body piercers use a disposable needle and were of the opinion that using a spring-loaded gun shatters the cartilage and increases the risk of infection. The best technique is open to debate and it may be that the perceived unsavoury environment of the body-piercing studio represents a safer option than the more respectable or cheaper alternatives. The practice of body piercing in the UK remains uncontrolled. PMID:11485579

Jervis, P N; Clifton, N J; Woolford, T J

2001-07-01

296

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

297

Factors contributing to bone conduction: the outer ear.  

PubMed

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. PMID:12597184

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

2003-02-01

298

Ear candles: a triumph of ignorance over science.  

PubMed

Ear candles are hollow tubes coated in wax which are inserted into patients' ears and then lit at the far end. The procedure is used as a complementary therapy for a wide range of conditions. A critical assessment of the evidence shows that its mode of action is implausible and demonstrably wrong. There are no data to suggest that it is effective for any condition. Furthermore, ear candles have been associated with ear injuries. The inescapable conclusion is that ear candles do more harm than good. Their use should be discouraged. PMID:14979962

Ernst, E

2004-01-01

299

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

300

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

301

Emergency pediatric ear, nose, and throat imaging.  

PubMed

Pediatric ear, nose, and throat emergencies broadly comprise infection, trauma, and airway obstruction secondary to a multitude of etiologies. Imaging occupies center stage in the diagnosis of many of these conditions and their complications, making it imperative for radiologists and other physicians covering the pediatric emergency department to familiarize themselves with the imaging appearances of these entities. Toward this goal, this article describes the imaging features of common pediatric ear, nose, and throat emergencies. Differential considerations, potential fallacies, and complications have been discussed when appropriate. Because a sound knowledge of the most relevant, efficient, time, and cost-effective imaging modality is of undisputable value in the acute setting, the preferred modality for each specific condition has been outlined. Finally, in alignment with our commitment to using radiation judiciously, we have suggested using ultrasonography and magnetic resonance instead of computed tomography, where possible, to optimize cost-benefit ratio for our young patients. PMID:22964411

Chess, Mitchell A; Chaturvedi, Apeksha; Stanescu, A Luana; Blickman, Johan G

2012-10-01

302

A Rare Case of Petrified Ear  

PubMed Central

Calcification or ossification of the auricle, also referred to as petrified ear, is a rare diagnosis in dermatology. In medical literature, it has most often been attributed to trauma, hypothermia and frostbite, or hypercalcemia secondary to a metabolic or endocrine disorder, such as Addison's disease. Here, we report the clinical and radiologic findings of a 79-year-old African American male whose unilateral petrified auricle was an incidental finding. He had a preceding history of hyperparathyroidism and subsequent hypercalcemia treated with a subtotal parathyroidectomy three years prior to presentation. In addition to laboratory analysis, a history and physical examination was performed which revealed no other signs of hypercalcemia. Radiologic studies demonstrated partial ossification of the external auricular cartilage on the left side. The patient was diagnosed with the rare occurrence of a petrified ear. In light of this case, we provide a discussion concerning the possible etiologies of this diagnosis including appropriate patient evaluation and possible treatment recommendations.

Buikema, Kathryn E.; Adams, Erin G.

2012-01-01

303

Coryneform bacteria isolated from middle ear fluid.  

PubMed Central

Nineteen strains of facultatively anaerobic gram-positive rods isolated in pure culture from middle ear fluids were identified. All effusions were collected by tympanocentesis in children with acute otitis media. Identification of microorganisms to the genus level was done by studying the cell wall composition. Sixteen strains contain meso-diaminopimelic acid and arabinogalactan polymer but lack mycolic acids; therefore, these strains do not belong to a previously described taxon. Because of similarities with Corynebacterium afermentans (Centers for Disease Control group ANF-1), we temporarily classified these mycolateless strains ANF-1 like. Isolation of these microorganisms in pure culture from middle ear fluids collected by tympanocentesis is a strong argument for their involvement in acute otitis media.

Simonet, M; De Briel, D; Boucot, I; Minck, R; Veron, M

1993-01-01

304

High intensity anthropogenic sound damages fish ears.  

PubMed

Marine petroleum exploration involves the repetitive use of high-energy noise sources, air-guns, that produce a short, sharp, low-frequency sound. Despite reports of behavioral responses of fishes and marine mammals to such noise, it is not known whether exposure to air-guns has the potential to damage the ears of aquatic vertebrates. It is shown here that the ears of fish exposed to an operating air-gun sustained extensive damage to their sensory epithelia that was apparent as ablated hair cells. The damage was regionally severe, with no evidence of repair or replacement of damaged sensory cells up to 58 days after air-gun exposure. PMID:12558299

McCauley, Robert D; Fewtrell, Jane; Popper, Arthur N

2003-01-01

305

Aspect Modification of an EAR Application a  

NASA Astrophysics Data System (ADS)

We propose aspect modification of compiled Java programs for which source code and documentation are not available. Aspect oriented programming is used to trace the program execution and identify points, in which aspects implementing new functionalities should be applied. A special tool for aspect oriented program tracing was designed and implemented. A modification in an real Enterprise Application Archive (EAR), compiled, without source code and documentation is presented in this paper. Advantages and disadvantages of described concepts are pointed out.

Bluemke, Ilona; Billewicz, Konrad

306

Acute seismic sensitivity in the bullfrog ear.  

PubMed

Single axons in the auditory/vestibular nerve of the American bullfrog exhibit by far the most exquisite sensitivity to substrate-borne vibration yet reported for a quadruped vertebrate. Earlier dye-injection studies revealed that these axons, which are relatively insensitive to airborne sound, originate at the saccular and lagenar maculae of the bullfrog inner ear. The more sensitive axons exhibited clear responses to vibratory sinusoids with peak accelerations as low as 0.005 cm/s2. PMID:6982744

Koyama, H; Lewis, E R; Leverenz, E L; Baird, R A

1982-10-28

307

Scaling of the mammalian middle ear.  

PubMed

This study considers the general question how animal size limits the size and information receiving capacity of sense organs. To clarify this in the case of the mammalian middle ear, I studied 63 mammalian species, ranging from a small bat to the Indian elephant. I determined the skull mass and the masses of the ossicles malleus, incus and stapes (M, I and S), and measured the tympanic membrane area, A1. The ossicular mass (in mg) is generally negatively allometric to skull mass (in g), the regression equation for the whole material (excluding true seals) being y = 1.373 x(0.513). However, for very small mammals the allometry approaches isometry. Within a group of large mammals no distinct allometry can be discerned. The true seals (Phocidae) are exceptional by having massive ossicles. The size relations within the middle ear are generally rather constant. However, the I/M relation is slightly positively allometric, y = 0.554 x(1.162). Two particularly isometric relations were found; the S/(M + I) relation for the ossicles characterized by the regression equation y = 0.054 x(0.993), and the relation between a two-dimensional measure of the ossicles and the tympanic membrane ares, (M + I)2/3 /A1. As in isometric ears the sound energy collected by the tympanic membrane is linearly related to its area, the latter isometry suggests that, regardless of animal size, a given ossicular cross-sectional area is exposed to a similar sound-induced stress. Possible morphological middle ear adaptations to particular acoustic environments are discussed. PMID:7559173

Nummela, S

1995-05-01

308

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

2011-06-08

309

Epidemiology and aetiology of middle ear cholesteatoma.  

PubMed

A total of 500 patients with cholesteatoma diagnosed and operated during 1982-91 in the region of Tampere University Hospital and Mikkeli Central Hospital in Finland were analysed retrospectively. The mean annual incidence was 9.2 per 100,000 inhabitants (range 3.7-13.9) and during the study period the annual incidence decreased significantly. The incidence was higher among males under the age of 50 years. There was no accumulation of cholesteatoma diseases in lower social groups. The majority (72.4%) of cholesteatoma patients had suffered from otitis media episodes. Tympanostomy was carried out in 10.2% and adenoidectomy or adenotonsillectomy in 15.9% of all cholesteatoma ears prior to cholesteatoma surgery. Cholesteatoma behind an intact tympanic membrane with no history of otitis media was verified in 0.6% of patients and in cleft palate patients in 8%. In this study, 13.2% of patients had ear trauma or ear operation in anamnes. PMID:10478597

Kemppainen, H O; Puhakka, H J; Laippala, P J; Sipilä, M M; Manninen, M P; Karma, P H

1999-01-01

310

Middle-ear velocity transfer function, cochlear input immittance, and middle-ear efficiency in chinchilla.  

PubMed

The transfer function HV between stapes velocity VS and sound pressure near the tympanic membrane PTM is a descriptor of sound transmission through the middle ear (ME). The ME power transmission efficiency (MEE), the ratio of sound power entering the cochlea to power entering the middle ear, was computed from HV measured in seven chinchilla ears and previously reported measurements of ME input admittance YTM and ME pressure gain GMEP [Ravicz and Rosowski, J. Acoust. Soc. Am. 132, 2437-2454 (2012); J. Acoust. Soc. Am. 133, 2208-2223 (2013)] in the same ears. The ME was open, and a pressure sensor was inserted into the cochlear vestibule for most measurements. The cochlear input admittance YC computed from HV and GMEP is controlled by a combination of mass and resistance and is consistent with a minimum-phase system up to 27?kHz. The real part Re{YC}, which relates cochlear sound power to inner-ear sound pressure, decreased gradually with frequency up to 25 kHz and more rapidly above that. MEE was about 0.5 between 0.1 and 8?kHz, higher than previous estimates in this species, and decreased sharply at higher frequencies. PMID:24116422

Ravicz, Michael E; Rosowski, John J

2013-10-01

311

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

312

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

313

Regional biosynthesis of prostaglandins and hydroxyeicosatetraenoic acids from arachidonic acid in the rat stomach tissue  

Microsoft Academic Search

The present study was conducted to determine regional differences in the biosynthesis of prostaglandins (PGs) and hydroxyeicosatetraenoic acids (HETEs) in the rat stomach tissue (fundus, corpus and pyloric antrum) from radioactive arachidonic acid (AA). The radioactive metabolites were validated by RP-HPLC using non-radioactive AA as substrate. PGE2 was the major prostanoid in the tissue. The relative ratio of PGE2:PGF2?:PGD2 in

R. W Choue; Y Cho; V. A Ziboh

2003-01-01

314

Arachidonic acid and PGE 2 regulation of hepatic lipogenic gene expression  

Microsoft Academic Search

N-6 polyunsaturated fatty acids (PUFA) suppress hepatic and adipocyte de novo lipogenesis by inhibiting the transcription of genes encoding key lipogenic proteins. In cultured 3T3-L1 adipocytes, arachidonic acid (20:4,n-6) suppression of lipogenic gene expression requires cyclooxy- genase (COX) activity. In this study, we found no evidence to support a role for COX-1 or -2 in the 20:4,n-6 inhibition of hepatocyte

Michelle K. Mater; Annette P. Thelen; Donald B. Jump

315

Altered neuroinflammatory, arachidonic acid cascade and synaptic markers in postmortem Alzheimer’s disease brain  

Microsoft Academic Search

Alzheimer’s disease (AD), a progressive neurodegenerative disorder, is the leading cause of dementia in the elderly. A recent positron emission tomography imaging study demonstrated upregulated brain arachidonic acid (AA) metabolism in AD patients. Further, a mouse model of AD shows an increase in AA-releasing cytosolic phospholipase A2 (cPLA2) in brain, and a reduction in cPLA2 activity ameliorated cognitive deficits. These

J S Rao; S I Rapoport; H-W Kim

2011-01-01

316

Fungal production of eicosapentaenoic and arachidonic acids from industrial waste streams and crude soybean oil  

Microsoft Academic Search

A series of polyunsaturated fatty acids (PUFAs), including 5,8,11,14,17-cis-eicosapentaenoic acid (EPA) and 5,8,11,14-cis-arachidonic acid (ARA), have widespread nutritional and pharmaceutical value. This study investigated the potential production of the two economically important fatty acids with a fungal fermentation process. The substrates for the fungal fermentation process were crude soybean oil (SBO), a sucrose waste stream (SWS) and a soymeal waste

Ming H. Cheng; Terry H. Walker; Gregory J. Hulbert; D. Raj Raman

1999-01-01

317

Kinetic Isotope Effects in the Oxidation of Arachidonic Acid by Soybean Lipoxygenase-1  

PubMed Central

The reaction of soybean lipoxygenase-1 with linoleic acid has been extensively studied and displays very large kinetic isotope effects. In this work, substrate and solvent kinetic isotope effects as well as the viscosity dependence of the oxidation of arachidonic acid were investigated. The hydrogen atom abstraction step was rate-determining at all temperatures, but was partially masked by a viscosity-dependent step at ambient temperatures. The observed KIEs on kcat were large (~100 at 25 °C).

Jacquot, Cyril; Peng, Sheng; van der Donk, Wilfred A.

2008-01-01

318

The production potential of eicosapentaenoic and arachidonic acids by the red alga Porphyridium cruentum  

Microsoft Academic Search

The red microalgaPorphyridium cruentum is a new source for eicosapentanoic acid (EPA) and arachidonic acid (AA) fatty acids of potential pharmaceutical value. The\\u000a conditions leading to a high content of either fatty acid were investigated. The highest EPA content was obtained under conditions\\u000a resulting in high growth rate (2.4% of ash free dry weight in Strain 1380-1d). High AA content

Zvi Cohen

1990-01-01

319

Molecular Cloning, Expression and Characterization of an Endogenous Human Cytochrome P450 Arachidonic Acid Epoxygenase Isoform  

Microsoft Academic Search

A cDNA containing an open reading frame coding for a human cytochrome P450 arachidonic acid epoxygenase was isolated from a male human kidney cDNA library. Sequence analysis showed that, with few exceptions, this cDNA was nearly identical to the published sequence for human liver Cyp 2C8 (S. T. Okino et al., 1987, J. Biol. Chem. 262, 16072-16079) and encoded a

D. C. Zeldin; R. N. Dubois; J. R. Falck; J. H. Capdevila

1995-01-01

320

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

321

Bovine papillomavirus oncoprotein E5 affects the arachidonic acid metabolism in cells  

Microsoft Academic Search

The bovine papillomavirus type 1 (BPV-1) oncoprotein encoded by the E5 ORF is a small highly hydrophobic protein, which is capable of inducing oncogenic transformation of cells. We studied the effect of the BPV-1 E5 protein expression on the arachidonic acid metabolism in monkey (COS1) and human (C33A) cells. At relatively low protein concentrations the phospholipase A2 (PLA2) activity and

Ülo Väli; Ann Kilk; Mart Ustav

2001-01-01

322

Formula feeding potentiates docosahexaenoic and arachidonic acid biosynthesis in term and preterm baboon neonates  

Microsoft Academic Search

Infant formulas supplemented with docosahex- aenoic acid (DHA) and arachidonic acid (ARA) are now avail- able in the United States; however, little is known about the factors that affect biosynthesis. Baboon neonates were as- signed to one of four treatments: term, breast-fed; term, for- mula-fed; preterm (155 of 182 days gestation), formula-fed; and preterm, formulaDHA\\/ARA-fed. Standard formula had no DHA\\/ARA;

Eszter Sarkadi-Nagy; Vasuki Wijendran; Guan Yeu Diau; Angela Chueh Chao; Andrea T. Hsieh; Anu Turpeinen; Peter Lawrence; Peter W. Nathanielsz; J. Thomas Brenna

2003-01-01

323

Differential stimulation of luminol-enhanced chemiluminescence (CL) and arachidonic acid metabolism in rat peritoneal neutrophils  

SciTech Connect

Phorbol 12-myristate, 13-acetate (PMA) induced the production of radical oxygen species (ROS) from rat peritoneal neutrophils as assessed by CL. ROS generation occurred in a time- (maximum at 13.5 min) and dose- (concentration range of 1.7-498 nM) related fashion. However, 166 nM PMA did not induce either cyclooxygenase (CO) or lipoxygenase (LPO) product formation by 20 min post-stimulation. Conversely, A23187, at concentrations between 0.1 and 10 ..mu..M, stimulated both pathways of arachidonic acid metabolism, but had little or no effect upon ROS production. When suboptimal concentrations of PMA (5.5 nM) and A23187 (0.1-1 ..mu..M) were coincubated with the neutrophils, a synergistic ROS response was elicited. However, arachidonic acid metabolism in the presence of PMA was unchanged relative to A12187 alone. Nordihydroguaiaretic acid (NDGA) inhibited both PMA-induced CL (IC/sub 50/ = 0.9 ..mu..M) and A23187-induced arachidonic acid metabolism (IC/sub 50/ = 1.7 ..mu..M and 6.0 ..mu..M for LPO and CO, respectively). The mixed LPO-CO inhibitor, BW755C, behaved in a qualitatively similar manner to NDGA, whereas the CO inhibitors, indomethacin, piroxicam and naproxen had no inhibitory effect on ROS generation at concentrations as high as 100 ..mu..M. These results suggest that NDGA and BW755C may inhibit CL and arachidonic acid metabolism by distinct mechanisms in rat neutrophils.

Sturm, R.J.; Adams, L.M.; Cullinan, C.A.; Berkenkopf, J.W.; Weichman, B.M.

1986-03-05

324

Oxygen Radicals Mediate the Cerebral Arteriolar Dilation from Arachidonate and Bradykinin in Cats  

Microsoft Academic Search

SUMMARY. Topical application of sodium arachidonate (50-200 \\/ig\\/ml) or bradykinin (0.1-10 fjg\\/ml) on the brain surface of anesthetized cats caused dose-dependent cerebral arteriolar dilation. This dilation was blocked by 67-100% in the presence of superoxide dismutase and catalase. These enzymes did not affect the changes in arteriolar diameter caused by alterations in arterial blood Pco2\\/ or the arteriolar dilation from

Hermes A. Kontos; Enoch P. Wei; John T. Povlishock; Carole W. Christman

325

Stimulus-specific induction of phospholipid and arachidonic acid metabolism in human neutrophils  

Microsoft Academic Search

Phospholipid remodeling resulting in arachidonic acid (AA) release and metabolism in human neutrophils stimulated by calcium ionophore A23187 has been extensively studied, while data obtained using physiologically relevant stimuli is limited. Opsonized zymosan and immune complexes induced stimulus-specific alterations in lipid metabolism that were different from those induced by A23187. (³H)AA release correlated with activation of phospholipase A2 (PLA2) but

Richard W. Godfrey; Rosalie M. Manzi; Mike A. Clark; Sylvia T. Hoffstein

1987-01-01

326

Interference of arachidonic acid and its metabolites with TNF-? release by ochratoxin A from rat liver  

Microsoft Academic Search

We investigated the role of arachidonic acid and its metabolites on the ochratoxin A (OTA) provoked release of proinflammatory and apoptotic cytokine TNF-? from blood-free perfused rat liver. OTA induced TNF-? release dose- and time-dependently yielding 2600pg TNF-?\\/ml at 2.5?mol\\/l after 90min without significant release of LDH and lactate. Aristolochic acid, 50?mol\\/l, a phospholipase A2 inhibitor, and 10?mol\\/l of exogenous

L. AL-Anati; N. Katz; E. Petzinger

2005-01-01

327

Influence of arachidonic acid and phytoviruses on the hormonal system of potato plants grown in vitro  

Microsoft Academic Search

Changes in the phytohormonal system during the development of antivirus resistance was investigated. This resistance was induced\\u000a by arachidonic acid (AA) in potato plants (Solanum tuberosum L.) grown in vitro. The plants in tubes were treated with AA 7 days before infection with tobacco mosaic virus or potato X virus. These plants\\u000a were used for ABA, IAA, and cytokinin quantification.

N. A. Rozhnova; G. A. Gerashchenkov

2006-01-01

328

Assessment of the arachidonic acid content in foods commonly consumed in the American diet  

Microsoft Academic Search

Arachidonic acid (AA) is an extremely important fatty acid involved in cell regulation. When provided in the diet, it is cogently\\u000a incorporated in membrane phospholipids and enhances eicosanoid biosynthesis in vivo and in vitro; however, controversy exists as to the levels of AA in food and in the diet. This study determined the amount of AA in cooked\\u000a and raw

Laura Taber; Chun-Hung Chiu; Jay Whelan

1998-01-01

329

A human dietary arachidonic acid supplementation study conducted in a metabolic research unit: Radionale and design  

Microsoft Academic Search

While there are many reports of studies that fed arachidonic acid (AA) to animals, there are very few reports of AA feeding\\u000a to humans under controlled conditions. This 130-d study was conceived as a controlled, symmetrical crossover design with healthy,\\u000a adult male volunteers. They lived in the metabolic research unit (MRU) of the Western Human Nutrition Research (WHNRC) for\\u000a the

G. J. Nelson; D. S. Kelly; E. A. Emken; S. D. Phinney; David Kyle; Aldo Ferretti

1997-01-01

330

Lysophosphatidylcholine induces arachidonic acid release and calcium overload in cardiac myoblastic H9c2 cells  

Microsoft Academic Search

Lysophosphatidylcholine (lyso-PC) and arachido- nate are products of phosphatidylcholine hydrolysis by phospholipase A 2 . In this study, the modulation of arachido- nate release by exogenous lyso-PC in rat heart myoblastic H9c2 cells was examined. Incubation of H9c2 cells with lyso-PC resulted in an enhanced release of arachidonate in both a time- and dose-dependent fashion. Lyso-PC species containing palmitoyl (C

Leonard S. Golfman; Norman J. Haughey; Jason T. Wong; Jenny Y. Jiang; Douglas Lee; Jonathan D. Geiger; Patrick C. Choy

331

5Lipoxygenase Metabolites of Arachidonic Acid Regulate Volume Decrease by Mudpuppy Red Blood Cells  

Microsoft Academic Search

.   We examined whether metabolites of arachidonic acid (AA) regulate K+ efflux during regulatory volume decrease (RVD) by mudpuppy red blood cells (RBCs). Volume regulation was inhibited by the\\u000a phospholipase A2 antagonists mepacrine (10 ?m) and ONO-RS-082 (10 ?m); the inhibitory effect of ONO-RS-082 was reversed by gramicidin (5 ?m). Eicosatetraynoic acid (ETYA, 100 ?m), a general antagonist of AA

D. B. Light; T. M. Mertins; J. A. Belongia; C. A. Witt

1997-01-01

332

Thiyl radicals in biosystems: inhibition of the prostaglandin metabolism by the cis– trans-isomerization of arachidonic acid double bonds  

Microsoft Academic Search

This paper describes parallel and comparative experiments on the enzymatic cyclooxygenase (COX) driven conversion of arachidonic acid (AA, all-cis-5,8,11,14-eicosatetraenoic acid) into prostaglandins by using pure arachidonic acid and AA samples containing relatively small amounts of thiyl radical induced trans-isomers. The experiments were performed in a liquid aqueous model system using COX-1 as well as by the in vitro feeding of

Susanne Kratzsch; Karl Drößler; Helmut Sprinz; Ortwin Brede

2003-01-01

333

Bile Acid-induced Apoptosis in Hepatocytes Is Caspase6-dependent  

Microsoft Academic Search

Apoptosis induced by hydrophobic bile acids is thought to contribute to liver injury during cholestasis. Caspase-6 is an executioner caspase that also appears to have regulatory functions in hematopoetic cell lines. We aimed to elucidate the role of caspase-6 in bile acid-induced apoptosis. The major human hydrophobic bile acid, glycochenodeoxycholic acid (GCDCA, 75 mu mol\\/liter), rapidly induced caspase-6 cleavage in

C. Rust; N. Wild; C. Bernt; T. Vennegeerts; R. Wimmer; U. Beuers

2009-01-01

334

Effects of High-Frequency Oscillatory Ventilation on Oleic Acid-Induced Lung Injury in Sheep  

Microsoft Academic Search

High-frequency oscillatory ventilation (HFOV) is a possible mechanical method for open lung strategies. The aim of this study\\u000a was to examine whether HFOV has a beneficial effect on oleic acid-induced lung injury, with emphasis on changes in extravascular\\u000a lung water. Thirteen anesthetized sheep prepared with a lung lymph fistula and vascular catheters for monitoring were randomly\\u000a allocated to two experimental

Rikimaru Nakagawa; Tomonobu Koizumi; Koichi Ono; Sumiko Yoshikawa; Kenji Tsushima; Tetsutarou Otagiri

2008-01-01

335

Comparison of acid-induced cell wall loosening in Valonia ventricosa and in oat coleoptiles  

Microsoft Academic Search

The acid-induced loosening of cell walls of Valonia ventricosa has been compared to that of frozen-thawed oat coleoptiles. The two acid extension responses are similar in regard to the shape of the pH response curve and the increase in plastic compliance induced by acid treatment. In both systems the acid response can be inhibited by Ca\\/sup 2 +\\/ and in

M. Tepfer; R. E. Cleland

1979-01-01

336

The stability of the postulated wall-loosening enzyme in acid-induced growth  

Microsoft Academic Search

Long-term pretreatments with cycloheximide (CH) caused inhibition of subsequent acidinduced growth of Avena coleoptile segments, but only after 6 or more h of CH treatment. These results together with previous, published evidence with frozen-thawed tissue are consistent with the hypothesis that there exists a wall-loosening enzyme responsible for acid-induced elongation and that it has a half-life of at least 7–8

Morris G. Cline

1979-01-01

337

Factors Affecting the Elicitation of Sesquiterpenoid Phytoalexin Accumulation by Eicosapentaenoic and Arachidonic Acids in Potato 1  

PubMed Central

Eicosapentaenoic and arachidonic acids in extracts of Phytophthora infestans mycelium were identified as the most active elicitors of sesquiterpenoid phytoalexin accumulation in potato tuber slices. These fatty acids were found free or esterified in all fractions with elicitor activity including cell wall preparations. Yeast lipase released a major portion of eicosapentaenoic and arachidonic acids from lyophilized mycelium. Concentration response curves comparing the elicitor activity of the polyunsaturated fatty acids to a cell-free sonicate of P. infestans mycelium indicated that the elicitor activity of the sonicated mycelium exceeded that which would be obtained by the amount of eicosapentaenoic and arachidonic acids (free and esterified) present in the mycelium. Upon acid hydrolysis of lyophilized mycelium, elicitor activity was obtained only from the fatty acid fraction. However, the fatty acids accounted for only 21% of the activity of the unhydrolyzed mycelium and the residue did not enhance their activity. Centrifugation of the hydrolysate, obtained from lyophilized mycelium treated with 2n NaOH, 1 molarity NaBH4 at 100°C, yielded a supernatant fraction with little or no elicitor activity. Addition of this material to the fatty acids restored the activity to that which was present in the unhydrolyzed mycelium. The results indicate that the elicitor activity of the unsaturated fatty acids is enhanced by heat and base-stable factors in the mycelium.

Bostock, Richard M.; Laine, Roger A.; Kuc, Joseph A.

1982-01-01

338

Factors affecting the elicitation of sesquiterpenoid phytoalexin accumulation by eicosapentaenoic and arachidonic acids in potato.  

PubMed

Eicosapentaenoic and arachidonic acids in extracts of Phytophthora infestans mycelium were identified as the most active elicitors of sesquiterpenoid phytoalexin accumulation in potato tuber slices. These fatty acids were found free or esterified in all fractions with elicitor activity including cell wall preparations. Yeast lipase released a major portion of eicosapentaenoic and arachidonic acids from lyophilized mycelium. Concentration response curves comparing the elicitor activity of the polyunsaturated fatty acids to a cell-free sonicate of P. infestans mycelium indicated that the elicitor activity of the sonicated mycelium exceeded that which would be obtained by the amount of eicosapentaenoic and arachidonic acids (free and esterified) present in the mycelium. Upon acid hydrolysis of lyophilized mycelium, elicitor activity was obtained only from the fatty acid fraction. However, the fatty acids accounted for only 21% of the activity of the unhydrolyzed mycelium and the residue did not enhance their activity. Centrifugation of the hydrolysate, obtained from lyophilized mycelium treated with 2n NaOH, 1 molarity NaBH(4) at 100 degrees C, yielded a supernatant fraction with little or no elicitor activity. Addition of this material to the fatty acids restored the activity to that which was present in the unhydrolyzed mycelium. The results indicate that the elicitor activity of the unsaturated fatty acids is enhanced by heat and base-stable factors in the mycelium. PMID:16662691

Bostock, R M; Laine, R A; Ku?, J A

1982-11-01

339

Stimulation of equine eosinophil migration by hydroxyacid metabolites of arachidonic acid.  

PubMed Central

Lipoxygenase products of arachidonic acid are important mediators of inflammation, affecting several aspects of cell function. Monohydroxyeicosatetraenoic acid (mono-HETE) and 5,12-dihydroxyeicosatetraenoic acid (LTB4) enhance migration of both neutrophils and eosinophils in several species. The relative ability of positional isomers of HETE and of LTB4 to affect migration of equine eosinophils was studied. The 5, 8, 9, 11, 12, and 15 isomers of HETE were prepared by autooxidation of arachidonic acid, separated by sequential normal phase and reverse phase high performance liquid chromatography, and their identities verified by gas chromatography-mass spectrometry. Equine eosinophils were isolated to 30-70% purity on discontinuous metrizamide gradients. All isomers of HETE stimulated directed migration (chemotaxis) at concentrations ranging from 10(-5) to 10(-8) M. The relative activities of isomers were 11 greater than 9 = 8 = 5 greater than 12 greater than 15. The dihydroxy acid LTB4 maximally stimulated chemotaxis of equine eosinophils at a concentration of 3 X 10(-7) M. The eosinophil migration that resulted was less than the maximal stimulation observed in response to isomers of HETE. The results of our study suggest that equine eosinophils are excellent indicator cells for assay of arachidonic acid metabolites with chemotactic activity. Equine eosinophils are more sensitive to chemotactic stimulation by HETEs than cells from other animal species but are far less sensitive to stimulation by LTB4.

Potter, K. A.; Leid, R. W.; Kolattukudy, P. E.; Espelie, K. E.

1985-01-01

340

Brain synthesis and cerebrovascular action of epoxygenase metabolites of arachidonic acid.  

PubMed

The purpose of this study was to determine if whole brain makes epoxygenase metabolites of arachidonic acid and, if so, whether they are vasoactive on the cerebral microcirculation. Blood-free mouse brain slices were incubated with exogenous radiolabeled arachidonic acid, and the extracted metabolites were resolved by HPLC. Metabolite structures were confirmed by gas chromatography/mass spectrometry. In addition to prostaglandins, leukotriene B4, and hydroxyeicosatetraenoic acids, mouse brain metabolized arachidonic acid into several other compounds. Among them, we identified 5,6- and 14,15-epoxyeicosatrienoic acid. Next, we tested the effect of topical application of brain-synthesized 5,6-epoxyeicosatrienoic acid and synthetic epoxyeicosatrienoic acids on in vivo rabbit cerebral arteriolar diameter using the cranial window technique and in vivo microscopy. Brain-synthesized 5,6-epoxyeicosatrienoic acid caused a transient 28% arteriolar dilation, similar to that produced by 5 micrograms/ml of synthetic 5,6-epoxyeicosatrienoic acid. A concentration of synthetic 14,15- and 11,12-epoxyeicosatrienoic acid of 5 micrograms/ml CSF had little or no effect on diameter, whereas 8,9-epoxyeicosatrienoic acid caused a maximum dilation of 8%. These studies suggest that brain-synthesized 5,6-epoxyeicosatrienoic acid may play a role in the normal or pathophysiological regulation of the cerebral microcirculation. PMID:1729396

Amruthesh, S C; Falck, J R; Ellis, E F

1992-02-01

341

Glutathione peroxidase activity and metabolism of arachidonic acid in peripheral blood mononuclear cells from elderly subjects.  

PubMed

1. Since ageing has been associated with a decrease in both immune responses and antioxidant defences, this study was undertaken to compare the glutathione peroxidase activity in peripheral blood mononuclear cells of healthy elderly and young donors. The mean value of glutathione peroxidase activity was significantly lower in the aged group (-36%) than that observed in the young control group (n = 10). 2. This defect was accompanied by a marked increase (+106%) in the oxygenated metabolism of endogenous arachidonic acid by lipoxygenases as judged by the radiolabel associated with hydroxyeicosatetraenoic acids in [3H]arachidonic acid-prelabelled peripheral blood mononuclear cells, whereas the cyclo-oxygenase activity, estimated by the radiolabel associated with thromboxane B2, was not significantly altered. 3. Upon stimulation by the mitogenic lectin concanavalin A, the radioactivity associated with total eicosanoids (free arachidonic acid plus hydroxyeicosatetraenoic acids plus thromboxane B2) was significantly increased over basal levels in the peripheral blood mononuclear cells of both the elderly and the control groups. However, the mitogen-induced increase was lower in the elderly group (+48%) than in the control group (+131%). Upon concanavalin A stimulation, the radioactivity of hydroxyeicosatetraenoic acids was increased by only 96% in peripheral blood mononuclear cells from the elderly group compared with 350% in control cells. Similarly, the radioactivity associated with thromboxane B2 was increased by only 82% in peripheral blood mononuclear cells from the elderly group compared with 218% in control cells.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8403789

Meskini, N; Nemoz, G; Chapuy, P; Haond, P; Pageaux, J F; Vericel, E; Lagarde, M; Prigent, A F

1993-08-01

342

Metabolism of arachidonic acid in ionophore-stimulated neutrophils. Esterification of a hydroxylated metabolite into phospholipids.  

PubMed Central

[14C]Arachidonic acid incubated with human neutrophils was esterified into phospholipids and triglycerides. Stimulation of these labeled neutrophils with ionophore A23187 (2 microM) results in release of [14C]arachidonate from phospholipid and its metabolism to prostaglandin E2 and 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), a lipoxygenase product. The released arachidonate is also metabolized to a polar lipid of unknown composition here disignated compound A. 5-HETE was found to be released into the medium and then taken up again by the cells. To determine its metabolic fate, [14C]5-HETE was prepared biosynthetically, purified, and incubated with stimulated, unlabeled neutrophils. Most of the radioactivity entered the cells and was esterified into phospholipids and triglycerides. The radiolabeled complex lipids were saponified, and the released fatty acids cochromatographed with authentic 5-HETE. The esterification of 5-HETE, a hydroxylated fatty acid, into membrane phospholipids may be an example of a more generalized mechanism for altering membrane characteristics.

Stenson, W F; Parker, C W

1979-01-01

343

Molecular mechanisms of PKCalpha localization and activation by arachidonic acid. The C2 domain also plays a role.  

PubMed

Arachidonic acid, one of the major unsaturated fatty acids released during cell stimulation, participates in the signaling necessary for activation of different enzymes, including protein kinase C (PKC). Here, we demonstrate that arachidonic acid is a direct activator of PKCalpha, but needs the cooperation of Ca(2+) to exert its function. By using several mutants of the C2 and C1 domains, we were able to determine the molecular mechanism of this activation. More specifically, site-directed mutagenesis in key residues found in the C2 domain showed that the Ca(2+)-binding region was essential for the arachidonic acid-dependent localization and activation of PKCalpha. However, the lysine-rich cluster, also located in the C2 domain, played no relevant role in either the membrane localization or activation of the enzyme. Moreover, site-directed mutagenesis in key residues placed in the C1A and C1B subdomains, which are responsible for the diacylglycerol/phorbil ester interaction, demonstrated that the C1A subdomain was involved in the membrane localization and activation mechanism. Taken together, these data suggest a very precise mechanism for PKCalpha activation by arachidonic acid, involving a sequential model of activation in which an increase in intracytosolic Ca(2+) leads to the interaction of arachidonic acid with the Ca(2+)-binding region; only after this step, does the C1A subdomain interact with arachidonic acid, leading to full activation of the enzyme. PMID:16476439

López-Nicolás, Rubén; López-Andreo, M José; Marín-Vicente, Consuelo; Gómez-Fernández, Juan C; Corbalán-García, Senena

2006-01-25

344

Chinchilla middle-ear admittance and sound power: high-frequency estimates and effects of inner-ear modifications.  

PubMed

The middle-ear input admittance relates sound power into the middle ear (ME) and sound pressure at the tympanic membrane (TM). ME input admittance was measured in the chinchilla ear canal as part of a larger study of sound power transmission through the ME into the inner ear. The middle ear was open, and the inner ear was intact or modified with small sensors inserted into the vestibule near the cochlear base. A simple model of the chinchilla ear canal, based on ear canal sound pressure measurements at two points along the canal and an assumption of plane-wave propagation, enables reliable estimates of Y(TM,) the ME input admittance at the TM, from the admittance measured relatively far from the TM. Y(TM) appears valid at frequencies as high as 17 kHz, a much higher frequency than previously reported. The real part of Y(TM) decreases with frequency above 2 kHz. Effects of the inner-ear sensors (necessary for inner ear power computation) were small and generally limited to frequencies below 3 kHz. Computed power reflectance was ~0.1 below 3.5 kHz, lower than with an intact ME below 2.5 kHz, and nearly 1 above 16 kHz. PMID:23039439

Ravicz, Michael E; Rosowski, John J

2012-10-01

345

Gas exchange function through the middle ear mucosa in piglets: comparative study of normal and inflamed ears.  

PubMed

The gas exchange function through the middle ear (ME) mucosa was investigated by comparing normal and inflamed ears in an animal model. Piglets were examined (n = 15) because their tympanic bulla closely resembles the human mastoid air cell system. Four untreated ears served as controls. Eleven ears were injected with glycerin into the tympanic bulla to induce inflammation and were studied as inflamed ears. Two respiratory conditions, spontaneous respiration and hyperventilation by a ventilator, were alternated repeatedly. ME pressure was measured intermittently by a tympanometer and blood gas was measured simultaneously. In all four normal ears, both ME pressure and carbon dioxide (CO2) partial pressure in the blood decreased in parallel following alternation of the respiratory conditions from spontaneous respiration to hyperventilation, while both pressure levels increased in parallel when respiration was changed from hyperventilation to spontaneous respiration. This result indicates that there is a gas exchange between the ME and the blood through the mucosa. However, ME pressure change in inflamed ears was limited, though the change in CO2 partial pressure in the blood was the same as that in normal ears. There was a significant difference in the degree of ME pressure change occurring in normal ears compared to that in inflamed ears, suggesting that inflammation of the mucosa reduced gas exchange function in the ME. PMID:10219389

Yamamoto, Y

1999-01-01

346

Chinchilla middle-ear admittance and sound power: High-frequency estimates and effects of inner-ear modifications  

PubMed Central

The middle-ear input admittance relates sound power into the middle ear (ME) and sound pressure at the tympanic membrane (TM). ME input admittance was measured in the chinchilla ear canal as part of a larger study of sound power transmission through the ME into the inner ear. The middle ear was open, and the inner ear was intact or modified with small sensors inserted into the vestibule near the cochlear base. A simple model of the chinchilla ear canal, based on ear canal sound pressure measurements at two points along the canal and an assumption of plane-wave propagation, enables reliable estimates of YTM, the ME input admittance at the TM, from the admittance measured relatively far from the TM. YTM appears valid at frequencies as high as 17 kHz, a much higher frequency than previously reported. The real part of YTM decreases with frequency above 2 kHz. Effects of the inner-ear sensors (necessary for inner ear power computation) were small and generally limited to frequencies below 3 kHz. Computed power reflectance was ?0.1 below 3.5?kHz, lower than with an intact ME below 2.5?kHz, and nearly 1 above 16?kHz.

Ravicz, Michael E.; Rosowski, John J.

2012-01-01

347

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

348

Ear detection based on improved AdaBoost algorithm  

Microsoft Academic Search

In this paper, we propose the ear detection approach under complex background which has two stages: off-line cascaded classifier training and on-line ear detection. In the stage of off-line training, considering the unique contour, the concave and convex of the ear, we apply the extended haar-like features to construct the space of the weak classifiers using the nearest neighbor norms.

Li Yuan; Feng Zhang

2009-01-01

349

Lightning causing inner ear damage and intracranial haematoma.  

PubMed

Lightning can transmit energy by way of the telephone network to the middle and the inner ear and thus cause pronounced injuries. In the patient mentioned here, the middle ear remained intact, while the inner ear was the seat of widespread damage combined with vascular rupture, the latter causing the formation of an intracranial haematoma. This was originally interpreted wrongly as a neoplasm. PMID:3760690

Poulsen, P; Knudstrup, P

1986-09-01

350

Ear Trauma in Orlu, Nigeria: A Five-Year Review  

Microsoft Academic Search

To review the presentation, types and aetiology of ear trauma and various factors affecting ear trauma in our patients over\\u000a a 5 year period. All patients treated for ear trauma over a 5 year period were studied using their clinical records. Data\\u000a extracted were analysed using SPSS version 11 software. The results were presented in simple descriptive and tabular forms.\\u000a Forty-one patients,

A. B. Chukuezi; J. N. Nwosu

351

The Soundry: How We Perceive Sound - The Ear  

NSDL National Science Digital Library

This page explores the structure of the ear and the way sound is received, transmitted, and understood by the brain. It explains the physical processes by which the outer, middle, and inner ears collect sound and relay it to nerve cells. Java simulations take the user on an interactive journey through the human ear, illustrating each concept being taught. This item is part of a module on the physics of sound for high school and middle school classrooms.

2007-09-17

352

Fatty acid-induced changes in vascular reactivity in healthy adult rats.  

PubMed

Dietary fatty acids (FAs) are known to modulate endothelial dysfunction, which is the first stage of atherosclerosis. However, their exact role in this initial phase is still unclear. The effects of isolated or combined (by 2) purified FAs from the main FA families were studied on the vascular response of isolated thoracic aorta in healthy rats to get a better understanding of the mechanisms of action of dietary FAs in regulating vascular endothelial function. Cumulative contraction curves to phenylephrine and relaxation curves to carbachol and then to sodium nitroprusside were obtained in the absence or presence of the FAs studied allowing endothelium-dependent and endothelium-independent ability of the smooth muscle to relax to be assessed in each experimental group. The endothelium-dependent vasodilator response to carbachol was lowered by eicosapentaenoic acid, whereas it was not altered either by docosahexaenoic acid alone or by combined eicosapentaenoic acid-docosahexaenoic acid, oleic acid, or stearic acid, and it was increased by linoleic acid (LA). A decreased phenylephrine-induced contraction was observed after incubation with arachidonic acid and with stearic acid. On the other hand, the endothelium-dependent relaxation was reduced by the addition of combined LA-arachidonic acid and LA-oleic acid. In conclusion, these data point out the differential effects of different types of FAs and of FAs alone vs combined on vascular reactivity. The complex nature of these effects could be partially linked to metabolic specificities of endothelial cells and to interactions between some FAs. PMID:16311092

Christon, Raymond; Marette, André; Badeau, Mylène; Bourgoin, Frédéric; Mélançon, Sébastien; Bachelard, Hélène

2005-12-01

353

Fly-ear inspired acoustic sensors for gunshot localization  

NASA Astrophysics Data System (ADS)

The supersensitive ears of the parasitoid fly Ormia ochracea have inspired researchers to develop bio-inspired directional microphone for sound localization. Although the fly ear is optimized for localizing the narrow-band calling song of crickets at 5 kHz, experiments and simulation have shown that it can amplify directional cues for a wide frequency range. In this article, a theoretical investigation is presented to study the use of fly-ear inspired directional microphones for gunshot localization. Using an equivalent 2-DOF model of the fly ear, the time responses of the fly ear structure to a typical shock wave are obtained and the associated time delay is estimated by using cross-correlation. Both near-field and far-field scenarios are considered. The simulation shows that the fly ear can greatly amplify the time delay by ~20 times, which indicates that with an interaural distance of only 1.2 mm the fly ear is able to generate a time delay comparable to that obtained by a conventional microphone pair with a separation as large as 24 mm. Since the parameters of the fly ear structure can also be tuned for muzzle blast and other impulse stimulus, fly-ear inspired acoustic sensors offers great potential for developing portable gunshot localization systems.

Liu, Haijun; Currano, Luke; Gee, Danny; Yang, Benjamin; Yu, Miao

2009-05-01

354

Local drug delivery to the inner ear using biodegradable materials.  

PubMed

The lack of an effective method of drug delivery has been a considerable obstacle in the development of novel therapeutics for inner ear diseases. However, several strategies have been investigated to achieve drug delivery to the inner ear, particularly for local application. Here, we review recent advances in the development of inner ear drug-delivery systems, focusing on biodegradable materials. Both synthetic and natural biodegradable materials have shown efficacy for inner ear drug delivery, resulting in an attenuation of hearing loss in animal models. We expect the further development of such drug-delivery systems to help translate the findings of experimental studies to clinical applications. PMID:22822510

Nakagawa, Takayuki; Ito, Juichi

2011-06-01

355

Alternative ear-canal measures related to absorbance.  

PubMed

Several alternative ear-canal measures are similar to absorbance in their requirement for prior determination of a Thévenin-equivalent sound source. Examples are (1) sound intensity level, (2) forward pressure level, (3) time-domain ear-canal reflectance, and (4) cochlear reflectance. These four related measures are similar to absorbance in their utilization of wideband stimuli and their focus on recording ear-canal sound pressure. The related measures differ from absorbance in how the ear-canal pressure is analyzed and in the type of information that is extracted from the recorded response. Sound intensity level and forward pressure level have both been shown to be better as measures of sound level in the ear canal compared with sound pressure level because they reduced calibration errors due to standing waves in studies of behavioral thresholds and otoacoustic emissions. Time-domain ear-canal reflectance may be used to estimate ear-canal geometry and may have the potential to assess middle ear pathology. Cochlear reflectance reveals information about the inner ear that is similar to what is provided by other types of otoacoustic emissions, and may have theoretical advantages that strengthen its interpretation. PMID:23900185

Neely, Stephen T; Stenfelt, Stefan; Schairer, Kim S

2013-07-01

356

Oxygen diving-induced middle ear under-aeration.  

PubMed

Middle ear negative pressure and effusions have been described after oxygen diving. The prevalence, dynamics and pathophysiology of this phenomenon are not clear, and were hence investigated in the present study. Thirty-four oxygen divers with normal otoscopic and tympanometric evaluation participated in the study. The subjects' symptoms were documented, and pneumatic otoscopy and tympanometry were repeated immediately after the completion of a 3 h, 15 feet oxygen dive, and 7 h later on awakening from the night's sleep. Most divers had positive otoscopic findings the morning after the dive, all of which cleared within 4 h of rising. A significant decrease was observed in average middle ear compliance (p = 0.0463, one way ANOVA), and an increase was found in the number of ears with tympanic compliance less than 0.3 ml (p = 0.0001, Kruskal-Wallis non-parametric ANOVA). In addition, 14.7% of the ears had type C, and 27.9% type B tympanograms the morning after the dive (p = 0.0001 chi2). The generalized nature of oxygen-induced middle ear under-aeration, combined with the dynamics of the symptoms and signs observed, make middle ear barotrauma, tympanic cavity oxygen absorption, and middle ear epithelial oxygen toxicity all unlikely explanations. The observed phenomenon and its dynamics might stem from a reversible derangement in a middle ear chemoreceptor reflex arch, which has recently been suggested as regulating middle ear aeration. PMID:7653265

Shupak, A; Attias, J; Aviv, J; Melamed, Y

1995-05-01

357

The risks of ear piercing in children.  

PubMed

Body piercing, and particularly ear piercing is becoming increasingly common in young children who may not be capable of properly caring for the pierced site. This may result in infection at the site and embedding of the earring. Infection and the subsequent necessity of removal of such earrings can cause considerable pain and distress. There is also a proven risk of inducing nickel allergy in these children which can be a problem in later life. The potential for serious infection such as Hepatitis B, Hepatitis C and HIV is not appreciated by the parents of these children. PMID:11310362

Macgregor, D M

2001-02-01

358

Local anaesthesia for middle ear surgery.  

PubMed

Thirty-two consecutive patients undergoing middle ear surgery using local anaesthesia were assessed on the adequacy of anaesthesia for their surgery, both by the patients themselves, and by the surgeon. A method of local anaesthesia is described which includes the possibility of inducing an iatrogenic transient homolateral facial weakness in order to simplify the technique of administration of anaesthesia. Both the surgeon and the patients were happy with the quality of the anaesthesia, and no adverse effects occurred either as a consequence of the local anaesthesia itself, or of the transient facial weakness. PMID:3243013

Lancer, J M; Fisch, U

1988-10-01

359

Pediatric ear, nose, and throat emergencies.  

PubMed

Acute otitis media is the most common infection for which antibiotics are prescribed in children, resulting in more than 20 million antibiotic prescriptions annually. New practice guidelines published by the American Academy of Pediatrics and the American Academy of Family Physicians call for the judicious use of antibiotics in view of increasing antibiotic resistance and the unclear necessity of the use of antibiotics in children with uncomplicated acute otitis media. This article reviews those guidelines, several other common ear, nose, and throat entities, including sinusitis and dental emergencies, and current strategies in diagnosis and treatment. PMID:16574522

Bernius, Morgen; Perlin, Donna

2006-04-01

360

DIBROMOACETIC ACID-INDUCED ELEVATIONS IN CIRCULATING ESTRADIOL: EFFECTS IN BOTH CYCLING AND OVARIECTOMIZED/STEROID-PRIMED FEMALE RATS  

EPA Science Inventory

RTD-03-031 Goldman, JM and Murr, AS. Dibromoacetic Acid-induced Elevations in Circulating Estradiol: Effects in Both Cycling and Ovariectomized/Steroid-primed Female Rats. Reproductive Toxicology (in press). Abstract Oral exposures to high concentrations of th...

361

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

362

Involvement of different protein kinases and phospholipases A2 in phorbol ester (TPA)-induced arachidonic acid liberation in bovine platelets.  

PubMed Central

The effect of various phospholipase A2 and protein kinase inhibitors on the arachidonic acid liberation in bovine platelets induced by the protein kinase activator 12-O-tetradecanoylphorbol-13-acetate (TPA) was studied. TPA stimulates arachidonic acid release mainly by activating group IV cytosolic PLA2 (cPLA2), since inhibitors of this enzyme markedly inhibited arachidonic acid formation. However, group VI Ca2+-independent PLA2 (iPLA2) seems to contribute to the arachidonic acid liberation too, since the relatively specific iPLA2 inhibitor bromoenol lactone (BEL) decreased arachidonic acid generation in part. The pronounced inhibition of the TPA-induced arachidonic acid release by the protein kinase C (PKC) inhibitors GF 109203X and Ro 31-82220, respectively, and by the p38 MAP kinase inhibitor SB 202190 suggests that the activation of the PLA2s by TPA is mediated via PKC and p38 MAP kinase.

Lehr, M; Griessbach, K

2000-01-01

363

Rebamipide Decreases the Susceptibility of Gastric Mucosa to Acid-Induced Injury in Rats by Inhibiting Neutrophil Activation  

Microsoft Academic Search

We previously demonstrated that activated neutrophils increased the susceptibility of gastric mucosa to acid-induced injury in rats. As rebamipide, an anti-ulcer agent, inhibits neutrophil activation, we examined whether the rebamipide reduces stress-induced gastric mucosal injury by decreasing susceptibility to acid-induced gastric mucosal injury in rats. Increase in both gastric mucosal permeability and gastric microvascular permeability evaluated by 51Cr-EDTA clearance and

Naoaki Harada; Kenji Okajima; Wenge Liu

2005-01-01

364

Arachidonate Metabolism Via lipoxygenase and 12L-hydroperoxy-5,8,10,14-icosatetraenoic Acid Peroxidase Sensitive to Anti-Inflammatory Drugs  

Microsoft Academic Search

The enzymes of arachidonate metabolism via the lipoxygenase pathway in human platelet cytosol have been characterized and partially purified. The lipoxygenase activity has a pH optimum of 7.3 and reaches half-maximal activity at an arachidonate concentration of 80 mu M. The oxidation of arachidonate by these enzymes is inhibited by reagents that modify sulfhydryl groups. Two separable lipoxygenase activities can

Marvin I. Siegel; Randy T. McConnell; Ned A. Porter; Pedro Cuatrecasas

1980-01-01

365

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

366

Evaluation of fungal flora in normal and diseased canine ears.  

PubMed

This study was undertaken to characterize otic fungal flora encountered in normal dogs, atopic dogs with no clinical or cytological evidence of otitis and dogs with otitis externa. Forty-two normal dogs, 23 atopic dogs and 32 dogs with otitis were included in the study. Samples for otic fungal culture and cytology were obtained from all animals, for a total of 194 ears. Sixty-seven ear samples (34%) were culture positive for saprophytic fungal organisms, as follows: 43 (64%) Penicillium species, 13 (19%) Aspergillus species and the remaining 17% comprised of various other saprophytic fungal organisms. Cytological evidence of saprophytic fungal colonization or infection was not found in any animal. There was no relationship between positive saprophytic fungal culture and any study group. Thirty-three ear samples (17%) were positive for Malassezia pachydermatis. Cytological findings of Malassezia were significantly associated with positive culture for Malassezia (P = 0.006 left ear; P = 0.019 right ear). Furthermore, increased numbers of Malassezia led to a higher chance of positive culture (P = 0.003 left ear; P = 0.008 right ear; McNemar's test). Malassezia pachydermatis was more likely to be cultured from ears with increased cerumen. Ear type (erect or pendulous) was not significantly associated with positive culture for Malassezia or saprophytic fungal organisms. There was no relationship between positive Malassezia culture and any study group; however, Malassezia was more likely to be cultured from individual dogs in the atopic or otitis groups that also had other dermatological signs consistent with allergic dermatitis and/or pyoderma (P = 0.031 left ear; P = 0.005 right ear). PMID:20868397

Campbell, Jacquelyn J; Coyner, Kimberly S; Rankin, Shelley C; Lewis, Thomas P; Schick, Anthea E; Shumaker, Amy K

2010-09-24

367

Clavulanic acid induces penile erection and yawning in male rats: comparison with apomorphine.  

PubMed

The beta-lactamase inhibitor clavulanic acid induced penile erection and yawning in a dose dependent manner when given intraperitoneally (IP, 0.05-5mg/kg), perorally (OS, 0.1-5mg/kg) and intracereboventricularly (ICV, 0.01-5 ?g/rat) to male rats. The effect resembles that of the dopamine receptor agonist apomorphine given subcutaneously (SC) (0.02-0.25mg/kg), although the responses of the latter followed a U inverted dose-response curve, disappearing at doses higher than 0.1mg/kg. Clavulanic acid responses were reduced by about 55% by haloperidol, a dopamine D2 receptor antagonist (0.1mg/kg IP), and by d(CH(2))(5)Tyr(Me)(2)-Orn(8)-vasotocin, an oxytocin receptor antagonist (2 ?g/rat ICV), both given 15 min before clavulanic acid. A higher reduction of clavulanic acid responses (more than 80%) was also found with morphine, an opioid receptor agonist (5mg/kg IP), and with mianserin, a serotonin 5HT(2c) receptor antagonist (0.2mg/kg SC). In contrast, no reduction was found with naloxone, an opioid receptor antagonist (1mg/kg IP). The ability of haloperidol, d(CH(2))(5)Tyr(Me)(2)-Orn(8)-vasotocin and morphine to reduce clavulanic acid induced penile erection and yawning suggests that clavulanic acid induces these responses, at least in part, by increasing central dopaminergic neurotransmission. Dopamine in turn activates oxytocinergic neurotransmission and centrally released oxytocin induces penile erection and yawning. However, since both penile erection and yawning episodes were reduced not only by the blockade of central dopamine and oxytocin receptors and by the stimulation of opioid receptors, which inhibits oxytocinergic neurotransmission, but also by mianserin, an increase of central serotonin neurotransmission is also likely to participate in these clavulanic acid responses. PMID:23234836

Sanna, Fabrizio; Melis, Maria Rosaria; Angioni, Laura; Argiolas, Antonio

2012-12-09

368

Lipopolysaccharide Stimulates Butyric Acid-Induced Apoptosis in Human Peripheral Blood Mononuclear Cells  

PubMed Central

We previously reported that butyric acid, an extracellular metabolite from periodontopathic bacteria, induced apoptosis in murine thymocytes, splenic T cells, and human Jurkat T cells. In this study, we examined the ability of butyric acid to induce apoptosis in peripheral blood mononuclear cells (PBMC) and the effect of bacterial lipopolysaccharide (LPS) on this apoptosis. Butyric acid significantly inhibited the anti-CD3 monoclonal antibody- and concanavalin A-induced proliferative responses in a dose-dependent fashion. This inhibition of PBMC growth by butyric acid depended on apoptosis in vitro. It was characterized by internucleosomal DNA digestion and revealed by gel electrophoresis followed by a colorimetric DNA fragmentation assay to occur in a concentration-dependent fashion. Butyric acid-induced PBMC apoptosis was accompanied by caspase-3 protease activity but not by caspase-1 protease activity. LPS potentiated butyric acid-induced PBMC apoptosis in a dose-dependent manner. Flow-cytometric analysis revealed that LPS increased the proportion of sub-G1 cells and the number of late-stage apoptotic cells induced by butyric acid. Annexin V binding experiments with fractionated subpopulations of PBMC in flow cytometory revealed that LPS accelerated the butyric acid-induced CD3+-T-cell apoptosis followed by similar levels of both CD4+- and CD8+-T-cell apoptosis. The addition of LPS to PBMC cultures did not cause DNA fragmentation, suggesting that LPS was unable to induce PBMC apoptosis directly. These data suggest that LPS, in combination with butyric acid, potentiates CD3+ PBMC T-cell apoptosis and plays a role in the apoptotic depletion of CD4+ and CD8+ cells.

Kurita-Ochiai, Tomoko; Fukushima, Kazuo; Ochiai, Kuniyasu

1999-01-01

369

The acid-induced folded state of Sac7d is the native state.  

PubMed Central

Sac7d unfolds at low pH in the absence of salt, with the greatest extent of unfolding obtained at pH 2. We have previously shown that the acid unfolded protein is induced to refold by decreasing the pH to 0 or by addition of salt (McCrary BS, Bedell J. Edmondson SP, Shriver JW, 1998, J Mol Biol 276:203-224). Both near-ultraviolet circular dichroism spectra and ANS fluorescence enhancements indicate that the acid- and salt-induced folded states have a native fold and are not molten globular. 1H,15N heteronuclear single quantum coherence NMR spectra confirm that the native, acid-, and salt-induced folded states are essentially identical. The most significant differences in amide 1H and 15N chemical shifts are attributed to hydrogen bonding to titrating carboxyl side chains and through-bond inductive effects. The 1H NMR chemical shifts of protons affected by ring currents in the hydrophobic core of the acid- and salt-induced folded states are identical to those observed in the native. The radius of gyration of the acid-induced folded state at pH 0 is shown to be identical to that of the native state at pH 7 by small angle X-ray scattering. We conclude that acid-induced collapse of Sac7d does not lead to a molten globule but proceeds directly to the native state. The folding of Sac7d as a function of pH and anion concentration is summarized with a phase diagram that is similar to those observed for other proteins that undergo acid-induced folding except that the A-state is encompassed by the native state. These results demonstrate that formation of a molten globule is not a general property of proteins that are refolded by acid.

Bedell, J. L.; McCrary, B. S.; Edmondson, S. P.; Shriver, J. W.

2000-01-01

370

alpha-Fetoprotein-mediated transfer of arachidonic acid into cultured cloned cells derived from a rat rhabdomyosarcoma.  

PubMed

alpha-Fetoprotein (AFP) is a major constituent of embryonal plasma and a physiological carrier of free fatty acids. The purpose of the present work was to study the mechanism by which fatty acids bound to AFP are transferred to living cells. Radiolabeled rat AFP and arachidonic acid were used to follow up the uptake and metabolism of both the protein and the fatty acid by rhabdomyosarcoma cells isolated from a nickel-induced rat tumor. Time course uptake of AFP and arachidonic acid by these cells exhibited a saturable profile at both 4 and 37 degrees C. A diffusible nonsaturable uptake of arachidonic acid was observed in experiments at both 4 and 37 degrees C with preparations of fixed AFP content and increased molar amounts of arachidonic acid (up to 8-fold molar excess). On the contrary, saturable binding and uptake of fatty acid and protein were evidenced when the molar ratio of arachidonic to AFP was fixed at 0.5, and the concentration of both increased simultaneously. This suggests that, under physiological conditions (low fatty acid to AFP ratio), the uptake of arachidonic acid by the tumor cells is regulated by the protein. Fatty acid distribution in cell lipids after 2 and 24 h of culture at 37 degrees C, in the presence of arachidonic acid bound to AFP, revealed that this fatty acid was mainly incorporated in cell phospholipids. At 4 degrees C, however, the totality of cell-associated arachidonic acid was in the unesterified form. Pulse-chase experiments showed that about 25 and 40% of the AFP initially taken up by cells were released undegraded after 6 and 60 min, respectively. Under the same conditions, nearly all the arachidonic acid remained in the cells. Taken together, these facts suggest a two-receptor model for the physiological uptake of fatty acids. The AFP binds to an AFP receptor and the fatty acid is then removed and transported inside the cell by a specific fatty acid-binding protein. PMID:2434503

Uriel, J; Naval, J; Laborda, J

1987-03-15

371

21 CFR 874.4350 - Ear, nose, and throat fiberoptic light source and carrier.  

Code of Federal Regulations, 2010 CFR

...Ear, nose, and throat fiberoptic light source and carrier. 874.4350 Section...Ear, nose, and throat fiberoptic light source and carrier. (a) Identification...ear, nose, and throat fiberoptic light source and carrier is an...

2010-04-01

372

21 CFR 874.4350 - Ear, nose, and throat fiberoptic light source and carrier.  

Code of Federal Regulations, 2010 CFR

...Ear, nose, and throat fiberoptic light source and carrier. 874.4350 Section...Ear, nose, and throat fiberoptic light source and carrier. (a) Identification...ear, nose, and throat fiberoptic light source and carrier is an...

2009-04-01

373

21 CFR 874.5300 - Ear, nose, and throat examination and treatment unit.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Ear, nose, and throat examination and treatment...SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Therapeutic Devices § 874.5300 Ear, nose, and throat examination and...

2013-04-01

374

21 CFR 874.4250 - Ear, nose, and throat electric or pneumatic surgical drill.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Ear, nose, and throat electric or pneumatic...SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4250 Ear, nose, and throat electric or...

2010-04-01

375

21 CFR 874.5220 - Ear, nose, and throat drug administration device.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Ear, nose, and throat drug administration...SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Therapeutic Devices § 874.5220 Ear, nose, and throat drug...

2010-04-01

376

21 CFR 874.5220 - Ear, nose, and throat drug administration device.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Ear, nose, and throat drug administration...SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Therapeutic Devices § 874.5220 Ear, nose, and throat drug...

2009-04-01

377

21 CFR 874.4500 - Ear, nose, and throat microsurgical carbon dioxide laser.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Ear, nose, and throat microsurgical carbon dioxide...CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4500 Ear, nose, and throat microsurgical carbon...

2010-04-01

378

21 CFR 874.4250 - Ear, nose, and throat electric or pneumatic surgical drill.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Ear, nose, and throat electric or pneumatic surgical...CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4250 Ear, nose, and throat electric or pneumatic...

2009-04-01

379

Anatomy of the Human Ear/Questions to Ask your Hearing Professional  

MedlinePLUS

... Section: Focus on Communication Anatomy of the Human Ear/ Questions to Ask your Hearing Professional Past Issues / ... A feeling of fullness or fluid in the ear Ringing in your ears (called tinnitus) Causes Aging ...

380

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

Code of Federal Regulations, 2013 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3620 Ear, nose, and throat synthetic polymer material. (a) Identification. Ear,...

2013-04-01

381

21 CFR 874.4500 - Ear, nose, and throat microsurgical carbon dioxide laser.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4500 Ear, nose, and throat microsurgical...microsurgical carbon dioxide laser is a device intended for the surgical excision of tissue from the ear, nose, and throat...

2013-04-01

382

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

Code of Federal Regulations, 2013 CFR

...false Ear, nose, and throat manual surgical instrument. 874.4420 Section 874...DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4420 Ear, nose, and throat manual surgical instrument. (a) Identification...

2013-04-01

383

Congenital malformations of the external and middle ear  

Microsoft Academic Search

With the focus on imaging, this paper gives a summarized view of the present knowledge on fields, which are necessary to know for a profound understanding of congenital malformations of the external and middle ear. Typical and less typical combinations of malformed parts of the ear can be derived from the embryogenesis. Clinical signs and audiometric findings lead to diagnosis

S. Kösling; M. Omenzetter; S. Bartel-Friedrich

2009-01-01

384

Representation of the Ear in Human Primary Somatosensory Cortex  

Microsoft Academic Search

We studied 13 healthy subjects with a multichannel magnetoencephalography (MEG) system to investigate the somatotopic representation of the ear in the primary somatosensory cortex (SI). We stimulated three parts of the left ear: the helix, the lobulus, and the tragus. The somatosensory-evoked magnetic fields (SEFs) were successfully measured in 7 of 13 subjects. Short-latency responses were analyzed using both single

T. Nihashi; R. Kakigi; O. Kawakami; M. Hoshiyama; K. Itomi; H. Nakanishi; Y. Kajita; S. Inao; J. Yoshida

2001-01-01

385

21 CFR 344.12 - Ear drying aid active ingredient.  

Code of Federal Regulations, 2013 CFR

...Food and Drugs 5 2013-04-01 2013-04-01 false Ear drying aid active ingredient. 344.12 Section 344.12...OVER-THE-COUNTER HUMAN USE Active Ingredients § 344.12 Ear drying aid active ingredient. The active ingredient...

2013-04-01

386

Formation of the Outer and Middle Ear, Molecular Mechanisms  

Microsoft Academic Search

The outer and middle ears collect, transmit, and amplify sound waves from the environment to stimulate sensory receptors located in the inner ear. Over the last decade enormous advances have been made in the understanding of the molecular mechanisms controlling the development of these areas. Molecular controls are set at different levels, including the production and differentiation of neural crest

Moisés Mallo

2003-01-01

387

Tetrapod-like middle ear architecture in a Devonian fish  

Microsoft Academic Search

Few fossils show the incipient stages of complex morphological transformations. For example, the earliest stages in the remodelling of the spiracular tract and suspensorium (jaw suspension) of osteolepiform fishes into the middle ear of tetrapods have remained elusive. The most primitive known tetrapods show a middle ear architecture that is very different from osteolepiforms such as Eusthenopteron, with little indication

Martin D. Brazeau; Per E. Ahlberg

2006-01-01

388

Influences on clinical practice: the case of glue ear  

Microsoft Academic Search

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

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

1999-01-01

389

OTOTOXIC EFFECTS OF MIDDLE EAR GENTAMICIN INSTILLATION IN THE CHINCHILLA  

Microsoft Academic Search

Gentamicin sulphate is used clinically to produce vestibular organ damage in patients with intractable vertigo. The drug is given locally by middle ear instillation. In humans, gentamicin appears to have a more toxic effect on the vestibular parts of the inner ear than on the cochlea. However, cochlear effects are not insignificant and to further explore the utility of monitoring

R. V. Harrison; J. Chen; R. J. Mount; H. Hirakawa; A. Kakigi; N. Harel

390

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

391

The correlation of middle ear aeration with mastoid pneumatization  

Microsoft Academic Search

Atelectatic ears, which by definition are poorly aerated, are also usually associated with poor mastoid pneumatization. On the other hand, otosclerotic patients, whose middle ears are usually exceptionally well aerated, also have excellent mastoid pneumatization. Three unusual cases are presented, in which partial atelectasis developed in stapedectomized patients. In each case the mastoid was later found to be nonpneumatized, and

J. Sadé

1992-01-01

392

CT of adenomas of the middle ear and mastoid cavity  

SciTech Connect

A case of mixed type adenoma of the middle ear and mastoid is presented in which CT showed complete opacification of the middle ear and mastoid air cells with bulging of the tympanic membrane but without ossicular or bony destruction. 7 refs., 1 figs.

Van Thong Ho [McGuire Veterans Affairs Medical Center, Richmond, VA (United States); Rao, V.J.; Mikaelian, D.O. [Thomas Jefferson Univ. Hospital and Jefferson Medical College, Philadelphia, PA (United States)

1996-03-01

393

Differential Intensity Sensitivity of the Ear for Pure Tones  

Microsoft Academic Search

The ratio of the minimum perceptible increment in sound intensity to the total intensity, DeltaEE, which is called the differential sensitivity of the ear, was measured as a function of frequency and intensity. Measurements were made over practically the entire range of frequencies and intensities for which the ear is capable of sensation. The method used was that of beating

R. R. Riesz

1928-01-01

394

Infrared fiber interferometer for microvibration measurements in the inner ear  

Microsoft Academic Search

Investigation of the inner ear is still subject of basic research. Due to the small structures of the inner ear every suggested measurement technique, which includes loading of moving parts, will not be able to detect the oscillations correctly. Therefore an optical approach detecting microvibrations in the cochlea will be discussed. In heterodyne interferometry as compared to classical interferometry two

Edgar Fischer; R. Link; E. Dalhoff; S. Heim; Hans J. Tiziani; Hans-Peter Zenner; Anthony W. Gummer

1995-01-01

395

Finite-Element Model for Evaluation of Middle Ear Mechanics.  

National Technical Information Service (NTIS)

A computer model of the middle ear, ossicular chain and eardrum was established using the finite-element method. A preliminary comparison of the model with measurements made in human-cadaver ears shows that the model is in approximate agreement with the f...

E. W. Abel R. M. Lord

2001-01-01

396

Preventing Cauliflower Ear with a Modified Tie-Through Technique.  

ERIC Educational Resources Information Center

|Describes a quick, simple tie-through suture technique (in which a collodion packing is secured to the auricle with two buttons) for preventing cauliflower ear following external ear trauma in wrestlers and boxers. The technique ensures constant compression; multiple treatments for fluid reaccumulation are rarely necessary. (SM)|

Dimeff, Robert J.; Hough, David O.

1989-01-01

397

Cadherin expression in the inner ear of developing zebrafish  

Microsoft Academic Search

Cadherins are cell adhesion molecules that have been implicated in development of a variety of organs including the ear. In this study we analyzed expression patterns of three zebrafish cadherins (Cadherin-2, -4, and -11) in the embryonic and larval zebrafish inner ear using both in situ hybridization and immunocytochemical methods. All three Cadherins exhibit distinct spatiotemporal patterns of expression during

Z. M. Novince; E. Azodi; J. A. Marrs; P. A. Raymond; Q. Liu

2003-01-01

398

Inhibition of arachidonate 5-lipoxygenase triggers massive apoptosis in human prostate cancer cells  

PubMed Central

Diets high in fat are associated with an increased risk of prostate cancer, although the molecular mechanism is still unknown. We have previously reported that arachidonic acid, an omega-6 fatty acid common in the Western diet, stimulates proliferation of prostate cancer cells through production of the 5-lipoxygenase metabolite, 5-HETE (5-hydroxyeicosatetraenoic acid). We now show that 5-HETE is also a potent survival factor for human prostate cancer cells. These cells constitutively produce 5-HETE in serum-free medium with no added stimulus. Exogenous arachidonate markedly increases the production of 5-HETE. Inhibition of 5-lipoxygenase by MK886 completely blocks 5-HETE production and induces massive apoptosis in both hormone-responsive (LNCaP) and -nonresponsive (PC3) human prostate cancer cells. This cell death is very rapid: cells treated with MK886 showed mitochondrial permeability transition between 30 and 60 min, externalization of phosphatidylserine within 2 hr, and degradation of DNA to nucleosomal subunits beginning within 2–4 hr posttreatment. Cell death was effectively blocked by the thiol antioxidant, N-acetyl-l-cysteine, but not by androgen, a powerful survival factor for prostate cancer cells. Apoptosis was specific for 5-lipoxygenase—programmed cell death was not observed with inhibitors of 12-lipoxygenase, cyclooxygenase, or cytochrome P450 pathways of arachidonic acid metabolism. Exogenous 5-HETE protects these cells from apoptosis induced by 5-lipoxygenase inhibitors, confirming a critical role of 5-lipoxygenase activity in the survival of these cells. These findings provide a possible molecular mechanism by which dietary fat may influence the progression of prostate cancer.

Ghosh, Jagadananda; Myers, Charles E.

1998-01-01

399

Lipoxins: Novel Series of Biologically Active Compounds Formed from Arachidonic Acid in Human Leukocytes  

Microsoft Academic Search

Trihydroxytetraenes, a novel series of oxygenated derivatives formed from arachidonic acid in human leukocytes, were recently isolated [Serhan, C. N., Hamberg, M. & Samuelsson, B. (1984) Biochem. Biophys. Res. Commun. 118, 943-949]. The structure of the major compound was established--i.e., 5,6,15L-trihydroxy-7,9,11,13-icosatetraenoic acid. The present study reports the structure of a second member of the trihydroxytetraene series of compounds--i.e., 5D,14,15L-trihydroxy-6,8,10,12-icosatetraenoic acid.

Charles N. Serhan; Mats Hamberg; Bengt Samuelsson

1984-01-01

400

Effects of stilbenes isolated from medicinal plants on arachidonate metabolism and degranulation in human polymorphonuclear leukocytes  

Microsoft Academic Search

Studies were made on the effects of stilbene derivatives isolated from medicinal plants on arachidonate metabolism and degranulation in human polymorphonuclear leukocytes (PMN-L). Resveratrol (3,4?,5-trihydroxystilbene) isolated from the roots of Reynoutria japonica was found to inhibit the 5-lipoxygenase products 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), 5,12-dihydroxy-6,8,10,14-eicosatetraenoic acid (5,12-diHETE) and leukotriene C4(LTC4); its concentrations for 50% inhibition (IC50) were 8.90 × 10?6 M, 6.70

Yoshiyuki Kimura; Hiromichi Okuda; Michinori Kubo

1995-01-01

401

Effect of sesamin on mitochondrial and peroxisomal ?-oxidation of arachidonic and eicosapentaenoic acids in rat liver  

Microsoft Academic Search

The effects of dietary sesamin on the hepatic metabolism of arachidonic (AA) and eicosapentaenoic (EPA) acids, were investigated\\u000a with respect to their ?-oxidation and secretion as triacylglycerol (TG). For 2 wk, rats were fed three types of dietary oils:\\u000a (i) corn oil (control) group; (ii) FPA group: FPA ethyl esters\\/rapeseed oil=2?3; (iii) AA group: AA ethyl esters\\/palm oil\\/perilla\\u000a oil=2?2?1, with

Rumi Umeda-Sawada; Megumi Ogawa; Mayumi Nakamura; Osamu Igarashi

2001-01-01

402

Raloxifene and hormone replacement therapy increase arachidonic acid and docosahexaenoic levels in postmenopausal women  

Microsoft Academic Search

Estrogens may affect the essential n-6 and n-3 fatty acids arachidonic acid (AA; C20:4n-6) and docosahexaenoic acid (DHA; C22:6n-3). Therefore, we investigated the long-term effects of hormone replacement therapy and raloxifene, a selective estrogen-receptor modulator, in two randomized, double-blind, placebo-controlled studies. In study I, 95 healthy, non-hysterectomized, early postmenopausal women (age range 47-59 years) received one of the following treatments:

Erik J Giltay; Erik J J Duschek; Martijn B Katan; S. J. Neele; J. C. Netelenbos; P. L. Zock

2004-01-01

403

Chronic discharging ear in a child: are we missing something?  

PubMed

Chronic discharging ear, mostly due to middle or external ear infection, is one of the leading causes for seeking healthcare among the paediatric population in a developing country. However, a long-standing forgotten middle ear foreign body forms a rare cause for such presentation demanding a high index of suspicion from the clinicians. Most of them are iatrogenic or accidental, and are removed by conventional permeatal approach; need for tympanotomy is rarely documented in the recent literature. We report the first case where a large stone was introduced into the middle ear through a pre-existing tympanic membrane perforation by the child himself, and only the second documentation of removal of a middle ear foreign body by tympanotomy in a child. PMID:24145273

Mainak, D; Soumya, G; Gautam, B

2013-08-01

404

Microvascular salvage of a thrombosed total ear replant.  

PubMed

Microvascular replantation, when possible, is the treatment of choice for total ear amputations. Both arterial and venous reconstruction should be attempted. The present case report describes a successful total ear replantation in a 45-year-old woman whose ear was amputated due to a horse accident. Venous thrombosis subsequently occurred and was managed with anticoagulation and leech therapy. Eighty hours after the replantation, arterial thrombosis took place. The posterior auricular artery thrombosed anastomosis was resected and reconstructed with an interposition vein graft. This report illustrates the feasibility of the successful microvascular salvage of a thrombosed total ear replant. It suggests the need for close clinical monitoring of the replanted ear and prompt microvascular reexploration in an event of the loss of arterial flow. PMID:23640855

Senchenkov, Alex; Jacobson, Steven R

2013-05-02

405

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

PubMed

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. PMID:10990521

Boatman, D; Krauss, G

2000-10-01

406

Pinnaplasty: reshaping ears to improve hearing aid retention.  

PubMed

The hearing aid is extremely important to the deaf. A small number have difficulty in retaining the device because the ear is prominent or cup-shaped. This report describes 11 children whose ear shape was modified to improve hearing aid retention and one adult in whom an over set back ear was released to allow fitment of a postaural device. In eight of the 11 children treated, conservative measures such as double-sided tape and retention bands (Huggies) had been tried previously without success. The creation of an antihelical fold in a misshapen ear lacking such a fold provides a reinforcing strut which is useful to support a hearing aid. In patients whose ear had been excessively tethered by previous surgery, projection was restored by inserting a cartilage block behind the ear. In one child with ears tethered by previous surgery, costal cartilage was used not only to release both ears, but also to reconstruct a new helical rim on one side. Surgery enabled a normal postaural hearing aid to be worn in 17 of the 19 ears treated. The two failures deserve special mention. In one patient with a unilateral deformity and severe mental retardation, the dressings were pulled off immediately after surgery. In another patient with a bilateral problem, the appearance and hearing aid retention was improved, but there was not enough room in the postauricular sulcus on one side for the battery component to fit comfortably and an in-the-ear device is now used on that side. Pinnaplasty is a helpful strategy to improve hearing aid retention. Care must be taken not to overdo the set back so that enough room is left to retain the hearing device. PMID:17466611

Gault, David; Grob, Marion; Odili, Joy

2007-04-26

407

Wideband acoustic transfer functions predict middle-ear effusion  

PubMed Central

Objectives/Hypothesis Compare the accuracy of wideband acoustic transfer functions (WATFs) measured in the ear canal at ambient pressure to methods currently recommended by clinical guidelines for predicting middle-ear effusion (MEE). Study Design Cross-sectional validating diagnostic study among young children with and without MEE to investigate the ability of WATFs to predict MEE. Methods WATF measures were obtained in a MEE group of 44 children (53 ears, mean age 1.9 years) scheduled for middle-ear ventilation tube placement and a normal age-matched control group of 44 children (59 ears, mean age 1.8 years) with normal pneumatic otoscopic findings and no history of ear disease or middle-ear surgery. An otolaryngologist judged whether MEE was present or absent and rated tympanic-membrane (TM) mobility via pneumatic otoscopy. A likelihood-ratio classifier reduced WATF data (absorbance, admittance magnitude and phase) from 0.25 to 8 kHz to a single predictor of MEE status. Absorbance was compared to pneumatic otoscopy classifications of tympanic membrane (TM) mobility. Results Absorbance was reduced in ears with MEE compared to ears from the control group. Absorbance and admittance magnitude were the best single WATF predictors of MEE, but a predictor combining absorbance, admittance magnitude and phase was the most accurate. Absorbance varied systematically with TM mobility based on data from pneumatic otoscopy. Conclusions Results showed that absorbance is sensitive to middle-ear stiffness and MEE, and WATF predictions of MEE in young children are as accurate as that reported for methods recommended by the clinical guidelines.

Ellison, John C.; Gorga, Michael; Cohn, Edward; Fitzpatrick, Denis; Sanford, Chris A.; Keefe, Douglas H.

2012-01-01

408

Ear nurse specialists: New Zealand's unique answer for the treatment of otitis media with effusion, “Glue Ear  

Microsoft Academic Search

Introduction: The Ear Nurse Specialist (ENS) service, started in 1975 as a primary health initiative, now extends to include outpatient clinics in hospitals. There are 27 nurses employed in the ENS role. ENSs mostly work in community settings, operating mobile ear clinics equipped to deliver otoscopic expertise to the wider community and to families who have difficulty with transport. Mobile

B. Middleton; M. Couillault; C. Lloyd

2003-01-01

409

Self-amputation of the ear: three men amputate four ears within five months.  

PubMed

Four instances are presented of self-amputation of the pinna of the external ear carried out by three right-handed, white males between January 1993 and May 1993. The common characteristics of these subjects--two men with personality disorder and one with schizophrenia--are discussed and compared with other examples of self-mutilation involving the face and ears, including that of van Gogh. A survey of Australian and New Zealand prisons was conducted to determine the frequency of this form of self-mutilation within the last five years, and yielded only one other case. Connections exist between the amputees supporting the notion that self-mutilation is "contagious"; the relevance of this to issues of management is considered. PMID:8573057

Alroe, C J; Gunda, V

1995-09-01

410

Mechanics of the exceptional anuran ear  

PubMed Central

The anuran ear is frequently used for studying fundamental properties of vertebrate auditory systems. This is due to its unique anatomical features, most prominently the lack of a basilar membrane and the presence of two dedicated acoustic end organs, the basilar papilla and the amphibian papilla. Our current anatomical and functional knowledge implies that three distinct regions can be identified within these two organs. The basilar papilla functions as a single auditory filter. The low-frequency portion of the amphibian papilla is an electrically tuned, tonotopically organized auditory end organ. The high-frequency portion of the amphibian papilla is mechanically tuned and tonotopically organized, and it emits spontaneous otoacoustic emissions. This high-frequency portion of the amphibian papilla shows a remarkable, functional resemblance to the mammalian cochlea.

Segenhout, Johannes M.; van Dijk, Pim

2008-01-01

411

Recurrent syncope and chronic ear pain  

PubMed Central

An elderly gentleman presented to hospital with recurrent blackout episodes consistent with syncope and a 3-month history of right ear pain. Significant postural hypotension was recorded. White cell count and C reactive protein were elevated. MRI of the head and neck revealed a soft tissue abnormality in the right nasopharynx and base of skull. Tissue biopsies were obtained and microbiology specimens revealed a mixed growth of pseudomonas and diphtheroids. There was no histological evidence of malignancy. A diagnosis of skull base infection was made. Infective involvement of the carotid sinus was considered to be the cause of the recurrent syncope and postural hypotension. The patient responded well to a 12-week course of intravenous meropenem. Inflammatory markers returned to normal and a repeat MRI after 3 months of treatment showed significant resolution of infection. The syncopal episodes and orthostatic hypotension resolved in parallel with treatment of infection.

Clegg, Andrew; Daverede, Luis; Wong, Winson; Loney, Elizabeth; Young, John

2010-01-01

412

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

413

Modes of stimulation of the teleost ear.  

PubMed

Microphonic potentials were recorded from the inner ears of a catfish (Ictalurus punctatus) and an African mouthbreeder (Tilapia macrocephala) in response to underwater sound stimulation and direct vibration of the head. The shape of the vibratory isopotential functions of frequency was similar in both species up to 600 HZ. Above 600 HZ, the sensitivity of Ictalurus continued to increase to 4000 HZ while the sensitivity of Tilapia declined. Deflation of the swim bladder did not affect the response to vibration in either species, the response of Tilapia to the underwater sound stimulus being minimal and unaffected by removal of the swim bladder. Ictalurus was pressure-sensitive to above 4000 HZ, ther being a significant dedline in the response with deflation of the swimbladder. PMID:1206339

Fay, R R; Popper, A N

1975-04-01

414

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

415

Ellagic acid induces transcription of the rat glutathione S-transferase-Ya gene.  

PubMed

Induction of glutathione S-transferase (GST) enzymes can increase detoxification of carcinogens and reduce carcinogen-induced mutagenesis and tumorigenesis. To determine if the anticarcinogen ellagic acid induces cellular enzymes which detoxify carcinogens, we examined the effect of ellagic acid on the expression of glutathione S-transferase-Ya. Rats fed ellagic acid demonstrated significant increases in total hepatic GST activity, hepatic GST-Ya activity and hepatic GST-Ya mRNA. To determine if the observed increase in GST-Ya mRNA was due to ellagic acid inducing transcription of the GST-Ya gene, transfection studies were performed with plasmid constructs containing various portions of the 5' regulatory region of the rat GST-Ya gene. The transfection studies demonstrated that ellagic acid increased GST-Ya mRNA by inducing transcription of the GST-Ya gene and demonstrated that this induction is mediated through the antioxidant responsive element of the GST-Ya gene. PMID:7697830

Barch, D H; Rundhaugen, L M; Pillay, N S

1995-03-01

416

Uric Acid Induces Renal Inflammation via Activating Tubular NF-?B Signaling Pathway  

PubMed Central

Inflammation is a pathologic feature of hyperuricemia in clinical settings. However, the underlying mechanism remains unknown. Here, infiltration of T cells and macrophages were significantly increased in hyperuricemia mice kidneys. This infiltration of inflammatory cells was accompanied by an up-regulation of TNF-?, MCP-1 and RANTES expression. Further, infiltration was largely located in tubular interstitial spaces, suggesting a role for tubular cells in hyperuricemia-induced inflammation. In cultured tubular epithelial cells (NRK-52E), uric acid, probably transported via urate transporter, induced TNF-?, MCP-1 and RANTES mRNA as well as RANTES protein expression. Culture media of NRK-52E cells incubated with uric acid showed a chemo-attractive ability to recruit macrophage. Moreover uric acid activated NF-?B signaling. The uric acid-induced up-regulation of RANTES was blocked by SN 50, a specific NF-?B inhibitor. Activation of NF-?B signaling was also observed in tubule of hyperuricemia mice. These results suggest that uric acid induces renal inflammation via activation of NF-?B signaling.

Zhou, Yang; Fang, Li; Jiang, Lei; Wen, Ping; Cao, Hongdi; He, Weichun; Dai, Chunsun; Yang, Junwei

2012-01-01

417

Passage of albumin from the middle ear to the inner ear in otitis media in the chinchilla  

SciTech Connect

A study of the permeability of the middle ear-inner ear interface for macromolecules was carried out in chinchillas with open and obstructed eustachian tubes utilizing tritiated human serum albumin and immunoelectrophoresis. Tritiated albumin was placed in the round window niche area or normal animals and animals in which the eustachian tubes had been obstructed for 24 hours or 14 days. The tritiated albumin was allowed to remain in the middle ear cavity for 24 hours, Samples of middle ear effusion, perilymph, blood and cerebrospinal fluid were collected and measured for radioactivity. Radioactivity was demonstrated in the perilymph. Samples of middle ear effusions and perilymph were also studied by immunoelectrophoresis with goat antihuman albumin. Albumin placed in the round window niche of an experimental animal could be recovered unchanged in the perilymph. The results suggest a pathophysiologic explanation for the association of otitis media and sensorineural hearing loss or endolymphatic hydrops.

Goldberg, B.; Goycoolea, M.V.; Schleivert, P.M.; Shea, D.; Schachern, P.; Paparella, M.M.; Carpenter, A.M.

1981-08-01

418

Uptake and subcellular distribution of [3H]arachidonic acid in murine fibrosarcoma cells measured by electron microscope autoradiography  

PubMed Central

We have used quantitative electron microscope autoradiography to study uptake and distribution of arachidonate in HSDM1C1 murine fibrosarcoma cells and in EPU-1B, a mutant HSDM1C1 line defective in high affinity arachidonate uptake. Cells were labeled with [3H]arachidonate for 15 min, 40 min, 2 h, or 24 h. Label was found almost exclusively in cellular phospholipids; 92-96% of incorporated radioactivity was retained in cells during fixation and tissue processing. All incorporated radioactivity was found to be associated with cellular membranes. Endoplasmic reticulum (ER) contained the bulk of [3H]arachidonate at all time points in both cell types, while mitochondria, which contain a large portion of cellular membrane, were labeled slowly and to substantially lower specific activity. Plasma membrane (PM) also labeled slowly, achieving a specific activity only one-sixth that of ER at 15 min in HSDM1C1 cells (6% of total label) and one-third of ER in EPU-1B (10% of total label). Nuclear membrane (NM) exhibited the highest specific activity of labeling at 15 min in HSDM1C1 cells (twice that of ER) but was not preferentially labeled in the mutant. Over 24 h, PM label intensity increased to that of ER in both cell lines. However, NM activity diminished in HSDM1C1 cells by 24 h to a small fraction of that in ER. In response to agonists, HSDM1C1 cells release labeled arachidonate for eicosanoid synthesis most readily when they have been labeled for short times. Our results therefore suggest that NM and ER, sites of cyclooxygenase in murine fibroblasts, are probably sources for release of [3H]arachidonate, whereas PM and mitochondria are unlikely to be major sources of eicosanoid precursors.

1985-01-01

419

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

PubMed

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, PGE(2), and PGF(2?) 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. PMID:20656894

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

2010-07-23

420

Influence of phenolic constituents from Yucca schidigera bark on arachidonate metabolism in vitro.  

PubMed

Yucca schidigera Roezl. (Agavaceae) has been traditionally used to treat a variety of diseases including arthritis and rheumatism. Phenolic constituents isolated from yucca bark, such as resveratrol, trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene, and the yuccaols, have been shown to possess various activities in vitro, such as antioxidant, radical scavenging, iNOS expression inhibitory, and platelet aggregation inhibitory effects. In the present study, the influence of a phenolic-rich fraction from yucca bark and of its main phenolic constituents on key enzymes of arachidonate metabolism was investigated. The fraction and the pure phenolics were shown to inhibit COX-1, COX-2, and LTB 4 formation by 5-LOX in vitro to different extents. The degree of COX-1 inhibition was found to be strongly dependent on the substitution pattern of ring B of the stilbenic moiety. The same trend was observed for the COX-2 inhibitory potential, which was, however, in general much lower for the yuccaols as compared with resveratrol. Resveratrol was also the only compound possessing an LTB 4 formation inhibitory activity. The inhibitory activity on key enzymes of arachidonate metabolism observed in this study might contribute to the explanation of the anti-inflammatory and antiplatelet effects observed for Y. schidigera and its phenolic constituents. PMID:18778071

Wenzig, Eva M; Oleszek, Wieslaw; Stochmal, Anna; Kunert, Olaf; Bauer, Rudolf

2008-09-09

421

Arachidonic Acid Enhances Caffeine-Induced Cell Death via Caspase-Independent Cell Death  

PubMed Central

Caffeine is a globally consumed psychostimulant but can be fatal to cells at overdose exposures. Although caspase-dependent apoptosis plays a role in caffeine-induced cell death, the responsible intracellular signalling cascade remains incompletely understood. The cellular slime mould, Dictyostelium discoideum, does not possess caspase-dependent apoptotic machinery. Here, we observed that ablation of D. discoideum plaA, which encodes a phospholipase A2 (PLA2) homolog, leads to a decreased rate of cell death under high caffeine concentrations and to enhanced cell death with the addition of arachidonic acid. Moreover, the inhibition of PLA2 activity lead to a recovery of the survival rate in caspase-inhibited Hela cervical carcinoma cells under high caffeine concentrations, indicating that caffeine-induced cell death is enhanced via PLA2-dependent signalling. Our results indicate that arachidonic acid may be a general second messenger that negatively regulates caffeine tolerance via a caspase-independent cell death cascade, which leads to multiple effects in eukaryotic cells.

Kuwayama, Hidekazu

2012-01-01

422

Equine tracheal epithelial membrane strips - An alternate method for examining epithelial cell arachidonic acid metabolism  

SciTech Connect

Arachidonic acid metabolism by tracheal epithelium can be studied using enzymatically dispersed cell suspensions or cell cultures. Both techniques require considerable tissue disruption and manipulation and may not accurately represent in vivo activity. The authors have developed an alternate method for obtaining strips of equine tracheal epithelium without enzymatic digestion. In the horse, a prominent elastic lamina supports the tracheal epithelium. By physical splitting this lamina, they obtained strips ({le}12 x 1.5 cm) of pseudostratified columnar epithelium attached to a layer of elastic tissue 30-100 {mu}m thick. Epithelial strips (1.2 x 0.5 cm) were attached to plexiglass rods and incubated with ({sup 3}H)arachidonic acid in M199 medium (0.5 {mu}Ci/ml) for 24 hours at 37C. The strips incorporated 36{+-}4% (mean {+-} SEM) of the total radioactivity and released 8.0{+-}1.2% of incorporated radioactivity when stimulated by 5.0 {mu}M calcium ionophore A23187. The extracted supernatant was processed using HPLC, resulting in peaks of radioactivity that co-eluted with authentic PGE{sub 2}, PGF{sub 2}{alpha}, and 12-HETE standards. The greatest activity corresponded to the PGE{sub 2} and PGF{sub 2}{alpha} standards, which is a similar pattern to that reported for cultured human tracheal epithelium.

Gray, P.R.; Derksen, F.J.; Robinson, N.E.; Peter-Golden, M.L. (Michigan State Univ., East Lansing (United States) Univ. of Michigan, Ann Arbor (United States))

1990-02-26

423

Arachidonic and eicosapentaenoic acid metabolism in bovine neutrophils and platelets: effect of calcium ionophore  

SciTech Connect

Substitution of dietary fatty acids has potential for altering the inflammatory response. The purpose of the present study was to define the metabolites of arachidonic acid (AA) and eicosapentaenoic acid (EPA) secreted by bovine peripheral blood neutrophils and platelets. High performance liquid chromatography was used to characterize cyclooxygenase and lipoxygenase metabolites secreted in response to the calcium ionophore A23187. Cells were prelabelled with /sup 3/H-AA or /sup 3/H-EPA prior to challenge with the calcium ionophore. Bovine neutrophils secreted leukotriene B4 (LTB4) and 5-hydroxyeicosatetraenoic acid (5-HETE) as the major metabolites of AA, as well as the corresponding leukotriene B5 (LTB5) and 5-hydroxyeicosapentaenoic acid (5-HEPE) metabolites of EPA. Peptidoleukotrienes derived from /sup 3/H-AA or /sup 3/H-EPA were not detected under these conditions. The major tritiated metabolites secreted from bovine platelets were: thromboxane A2, measured as the stable metabolite thromboxane B2 (TXB2); hydroxyheptadecatrienoic acid (HHT) and 12-HETE derived from /sup 3/H-AA; and the omega-3 analogs TXB3 and 12-HEPE, derived from /sup 3/H-EPA. Preferred substrate specificities existed amongst the AA- and EPA-derived metabolites for the intermediary enzymes involved in the arachidonic acid cascade. These findings support the hypothesis that substitution of membrane-bound AA by EPA has potential for modulation of the host inflammatory response following cellular phospholipid mobilization.

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

1987-09-01

424

Evaluation of bioequivalency and toxicological effects of three sources of arachidonic acid (ARA) in domestic piglets.  

PubMed

Arachidonic acid (ARA) and docosahexaenoic acid (DHA) are routinely added to infant formula to support growth and development. We evaluated the bioequivalence and safety of three ARA-rich oils for potential use in infant formula using the neonatal pig model. The primary outcome for bioequivalence was brain accretion of ARA and DHA. Days 3-22 of age, domestic pigs were fed one of three formulas, each containing ARA at ?0.64% and DHA at ?0.34% total fatty acids (FA). Control diet ARA was provided by ARASCO and all diets had DHA from DHASCO (Martek Biosciences Corp., Columbia, MD). The experimental diets a1 and a2 provided ARA from Refined Arachidonic acid-rich Oil (RAO; Cargill, Inc., Wuhan, China) and SUNTGA40S (Nissui, Nippon Suisan Kaisha, Ltd., Tokyo, Japan), respectively. Formula intake and growth were similar across all diets, and ARA was bioequivalent across treatments in the brain, retina, heart, liver and day 21 RBC. DHA levels in the brain, retina and heart were unaffected by diet. Liver sections, clinical chemistry, and hematological parameters were normal. We conclude that RAO and SUNTGA40S, when added to formula to supply ?0.64% ARA are safe and nutritionally bioequivalent to ARASCO in domestic piglets. PMID:21722692

Tyburczy, Cynthia; Brenna, Margaret E; DeMari, Joseph A; Kothapalli, Kumar S D; Blank, Bryant S; Valentine, Helen; McDonough, Sean P; Banavara, Dattatreya; Diersen-Schade, Deborah A; Brenna, J Thomas

2011-06-21

425

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

426

Imaging upregulated brain arachidonic acid metabolism in HIV-1 transgenic rats  

PubMed Central

Human immunodeficiency virus (HIV)-associated infection involves the entry of virus-bearing monocytes into the brain, followed by microglial activation, neuroinflammation, and upregulated arachidonic acid (AA) metabolism. The HIV-1 transgenic (Tg) rat, a noninfectious HIV-1 model, shows neurologic and behavioral abnormalities after 5 months of age. We hypothesized that brain AA metabolism would be elevated in older HIV-1 Tg rats in vivo. Arachidonic acid incorporation from the plasma into the brain of unanesthetized 7-to-9-month-old rats was imaged using quantitative autoradiography, after [1-14C]AA infusion. Brain phospholipase (PLA2) activities and eicosanoid concentrations were measured, and enzymes were localized by immunostaining. AA incorporation coefficients k* and rates Jin, measures of AA metabolism, were significantly higher in 69 of 81 brain regions in HIV-1 Tg than in control rats, as were activities of cytosolic (c)PLA2-IV, secretory (s)PLA2, and calcium independent (i)PLA2-VI, as well as prostaglandin E2 and leukotriene B4 concentrations. Immunostaining of somatosensory cortex showed elevated cPLA2-IV, sPLA2-IIA, and cyclooxygenase-2 in neurons. Brain AA incorporation and other markers of AA metabolism are upregulated in HIV-1 Tg rats, in which neurologic changes and neuroinflammation have been reported. Positron emission tomography with [1-11C]AA could be used to test whether brain AA metabolism is upregulated in HIV-1-infected patients, in relation to cognitive and behavioral disturbances.

Basselin, Mireille; Ramadan, Epolia; Igarashi, Miki; Chang, Lisa; Chen, Mei; Kraft, Andrew D; Harry, G Jean; Rapoport, Stanley I

2011-01-01

427

Evaluation of Bioequivalency and Toxicological Effects of Three Sources of Arachidonic Acid (ARA) in Domestic Piglets  

PubMed Central

Arachidonic acid (ARA) and docosahexaenoic acid (DHA) are routinely added to infant formula to support growth and development. We evaluated the bioequivalence and safety of three ARA-rich oils for potential use in infant formula using the neonatal pig model. The primary outcome for bioequivalence was brain accretion of ARA and DHA. Days 3 to 22 of age, domestic pigs fed one of three formulas, each containing ARA at ~0.64% and DHA at ~0.34% total fatty acids (FA). Control diet ARA was provided by ARASCO® and all diets had DHA from DHASCO® (Martek Biosciences Corp., Columbia, MD). The experimental diets a1 and a2 provided ARA from Refined Arachidonic acid-rich Oil (RAO; Cargill, Inc., Wuhan, China) and SUNTGA40S (Nissui, Nippon Suisan Kaisha, Ltd., Tokyo, Japan), respectively. Formula intake and growth were similar across all diets, and ARA was bioequivalent across treatments in the brain, retina, heart, liver and day 21 RBC. DHA levels in the brain, retina and heart were unaffected by diet. Liver sections, clinical chemistry, and hematological parameters were normal. We conclude that RAO and SUNTGA40S, when added to formula to supply ~0.64% ARA are safe and nutritionally bioequivalent to ARASCO in domestic piglets.

Tyburczy, Cynthia; Brenna, Margaret E.; DeMari, Joseph A.; Kothapalli, Kumar S. D.; Blank, Bryant S.; Valentine, Helen; McDonough, Sean P.; Banavara, Dattatreya; Diersen-Schade, Deborah A.; Brenna, J. Thomas

2011-01-01

428

Physiological inhibitory effect of ocs in arachidonic acid-rich Parietochloris incisa (trebouxiophyceae, chlorophyta)  

NASA Astrophysics Data System (ADS)

Parietochloris incisa is an arachidonic acid-rich snow green alga. The main physiological profiles, such as ash free dry weight (AFDW), chlorophyll, carotenoid, protein and total fatty acids (TFA), in this alga exposed to old culture supernatant (OCS) at the decline phase or its crude ethyl acetate extracts (CEAE) were investigated by using tubular photobioreactors of different diameters. Results showed that both OCS and CEAE had strong inhibitory effect on the above physiological parameters. The longer the culture was exposed to OCS and the more CEAE were added into the algal culture, the more the above physiological properties were inhibited. Arachidonic acid (AA), the dominant component of fatty acids in this alga, was also seriously inhibited with respect to total TFA, AFDW of cell mass, or culture volume, due to a probable reduction of enzymes activities catalyzing chain elongation from C18; 1?9 to AA. These results incontestably evidenced that some CEAE dissolving substances existing in OCS. like auto-inhibitors, inhibited P. incisa growth through feedback. Hence, any efficient removal of auto-inhibitors from algal culture to decrease their bioactivity could be good for maximal production of desired products like AA.

Liu, Jian-Guo; Zhang, Cheng-Wu; Cohen, Zvi; Richmond, Amos

2002-09-01

429

Arachidonic acid metabolites contribute to the irreversible depolarization induced by in vitro ischemia.  

PubMed

Intracellular recordings were made from hippocampal CA1 neurons in rat slice preparations. Superfusion with oxygen- and glucose-deprived medium (in vitro ischemia) produced a rapid depolarization approximately 5 min after the onset of the superfusion. Even when oxygen and glucose were reintroduced immediately after rapid depolarization, the membrane depolarized further (persistent depolarization) and reached 0 mV (irreversible depolarization) after 5 min from the reintroduction. The pretreatment of the slice preparation with a phospholipase A2 (PLA2) inhibitor, para-bromophenacyl bromide, or a cytochrome p-450 inhibitor, 17-octadecynoic acid, significantly restored the membrane to the preexposure potential level after the reintroduction of oxygen and glucose. The administration of 14,15-epoxyeicosatrienoic acid or 20-hydroxyeicosatetraenoic acid did not change the latency of the rapid depolarization and did not allow the membrane potential to recover after the ischemic exposure. In contrast, after pretreatment with cyclooxygenase or lipoxygenase inhibitors, such as indomethacin, resveratrol, Dup-697, nordihydroguaiaretic acid, and 3,4-dihydrophenyl ethanol, a minority of neurons tested showed postischemic recovery from the persistent depolarization. Improved recovery was also seen after treatment with the free radical scavengers, edaravone and alpha-tocopherol. These results suggest that the activation of the arachidonic acid cascade via PLA2 and the free radicals produced by arachidonic acid metabolism contribute to the irreversible depolarization produced by in vitro ischemia. PMID:12917387

Tanaka, E; Niiyama, S; Sato, S; Yamada, A; Higashi, H

2003-08-13

430

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

SciTech Connect

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. (Vanderbilt Univ., Nashville, TN (USA))

1990-08-01

431

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

432

The target of arachidonic acid pathway is a new anticancer strategy for human prostate cancer  

PubMed Central

Recent epidemiological studies and animal experiments have demonstrated that nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the incidence of colorectal carcinoma. Cyclooxygenase (COX) is the principal target of NSAIDs. COX is the first oxidase in the process of prostaglandin production from arachidonic acid. COX enzyme may be involved in the initiation and/or the promotion of carcinogenesis due to NSAIDs inhibition of COX. Lipoxygenase (LOX) is also an initial enzyme in the pathway for producing leukotrienes from arachidonic acid. Similar to COX, LOX enzyme may also be involved in the initiation and/or promotion of carcinogenesis. Peroxisome proliferator activator-receptor (PPAR)-? is a ligand-activated transcriptional factor belonging to the steroid receptor superfamily. PPAR-? plays a role in both adipocyte differentiation and carcinogenesis. PPAR-? is one target for cell growth modulation of NSAIDs. In this review, we report the expression of COX-2, LOX and PPAR-? in human prostate cancer tissues as well as the effects of COX-2 and LOX inhibitors and PPAR-? ligand.

Matsuyama, Masahide; Yoshimura, Rikio

2008-01-01

433

Oxylipin Formation in Fungi: Biotransformation of Arachidonic Acid to 3Hydroxy5,8-tetradecadienoic Acid by Mucor genevensis  

Microsoft Academic Search

The soil fungusMucor genevensiswas shown to convert exogenous arachidonic acid to the oxylipin 3-hydroxy-5Z,8Z-tetradecadienoic acid (3-HTDE) as determined by gas chromatography\\/mass spectrometry. This metabolite was only found in the aqueous supernatant together with free linoleic acid, but not in the final fungal biomass. In contrast, the corresponding primary arachidonic acid metabolite (3R)-hydroxy-(5Z,8Z,11Z,14Z)-eicosatetraenoic acid (3-HETE), which has been earlier shown to

Carolina H. Pohl; Alfred Botha; Johan L. F. Kock; Dennis J. Coetzee; Piet J. Botes; Tankred Schewe; Santosh Nigam

1998-01-01

434

Combined effect of fluid and pressure on middle ear function.  

PubMed

In our previous studies, the effects of effusion and pressure on sound transmission were investigated separately. The aim of this study is to investigate the combined effect of fluid and pressure on middle ear function. An otitis media with effusion model was created by injecting saline solution and air pressure simultaneously into the middle ear of human temporal bones. Tympanic membrane displacement in response to 90 dB SPL sound input was measured by a laser vibrometer and the compliance of the middle ear was measured by a tympanometer. The movement of the tympanic membrane at the umbo was reduced up to 17 dB by the combination of fluid and pressure in the middle ear over the auditory frequency range. The fluid and pressure effects on the umbo movement in the fluid-pressure combination are not additive. The combined effect of fluid and pressure on the umbo movement is different compared with that of only fluid or pressure change in the middle ear. Negative pressure in fluid-pressure combination had more effect on middle ear function than positive pressure. Tympanometry can detect the middle ear pressure of the fluid-pressure combination. This study provides quantitative information for analysis of the combined effect of fluid and pressure on tympanic membrane movement. PMID:18162348

Dai, Chenkai; Wood, Mark W; Gan, Rong Z

2007-11-24

435

Combined Effect of Fluid and Pressure on Middle Ear Function  

PubMed Central

In our previous studies, the effects of effusion and pressure on sound transmission were investigated separately. The aim of this study is to investigate the combined effect of fluid and pressure on middle ear function. An otitis media with effusion model was created by injecting saline solution and air pressure simultaneously into the middle ear of human temporal bones. Tympanic membrane displacement in response to 90 dB SPL sound input was measured by a laser vibrometer and the compliance of the middle ear was measured by a tympanometer. The movement of the tympanic membrane at the umbo was reduced up to 17 dB by the combination of fluid and pressure in the middle ear over the auditory frequency range. The fluid and pressure effects on the umbo movement in the fluid-pressure combination are not additive. The combined effect of fluid and pressure on the umbo movement is different compared with that of only fluid or pressure change in the middle ear. Negative pressure in fluid-pressure combination had more effect on middle ear function than positive pressure. Tympanometry can detect the middle ear pressure of the fluid-pressure combination. This study provides quantitative information for analysis of the combined effect of fluid and pressure on tympanic membrane movement.

Dai, Chenkai; Wood, Mark W.; Gan, Rong Z.

2008-01-01

436

Middle ear transmission in the grass frog, Rana temporaria.  

PubMed

The anuran middle ear serves to transmit eardrum vibrations to the inner ear. In order to do this efficiently, the eardrum and middle ear must operate as an impedance transformer matching the low impedance of air to the higher impedance of the fluid-filled inner ear. In amniotes, one of the mechanisms used to achieve impedance transformation is to have the middle ear work as a force-amplifying lever system. Here, we present evidence that the grass frog middle ear also implements a lever system. The columellar footplate, which sits in the oval window, is firmly connected to the otic capsule along its ventral edge. Therefore, simple in-out movement of the columella is prevented while a rotational movement around the footplate's ventral edge is possible. The latter movement pattern was confirmed by laser vibrometry measurements of eardrum and footplate vibrations. The results showed that the footplate vibrations were 20-30 dB weaker than those of the eardrum and that the two structures vibrated 180 degrees out of phase (at low frequencies). The lever ratio was approximately 6, i.e. somewhat higher than lever ratios reported for amniotes. Hence, the middle ear lever probably makes a significant contribution to impedance matching in frogs. PMID:9447714

Jørgensen, M B; Kanneworff, M

1998-01-01

437

Why do patients with fibromyalgia complain of ear-related symptoms? Ear-related symptoms and otological findings in patients with fibromyalgia.  

PubMed

While fibromyalgia is frequently associated with ear-related symptoms such as feeling of ear fullness, earache, and tinnitus, the pathogenesis of these ear-related symptoms in fibromyalgia patients is unknown. Here, we focused on clarifying the pathogenesis of ear fullness, a particularly common symptom observed in fibromyalgia patients. Twenty patients diagnosed with fibromyalgia on outpatient psychosomatic treatment complaining of ear-related symptoms answered our questionnaire and underwent neurotological examination, including pure tone audiometry and Eustachian tube function testing. While ear-related symptoms were significantly exacerbated after onset of fibromyalgia, we noted no correlation between the presence or absence of feeling of ear fullness and abnormal findings on neurotological examination. Given our findings, we suspect that onset of ear fullness may be associated not with abnormal findings in the middle and inner ear function tests but with other causes, such as central desensitization. PMID:23700040

Iikuni, Fusako; Nomura, Yasuyuki; Goto, Fumiyuki; Murakami, Masato; Shigihara, Shuntaro; Ikeda, Minoru

2013-05-23

438

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

439

[Introduction to the surgery of the middle ear: general principles].  

PubMed

We study the basic guidelines of the middle ear surgery, having as target the recuperation of the anatomic functional integrity of ear. There are different important elements in the quality/quantity of the functional results as follows: The surgery technical method used. The actual pathology in the middle ear. The quality of eustachian tube function. The surgeon's experience and ability and several factors. We review the concept introduced by Wullstein called it tympanoplasty from 1952 till nowadays. Finally, we described the most frequent surgery procedures used in the daily practice. PMID:8129965

Babighian, G; Domínguez, M J

440

Increasing dietary linoleic acid does not increase tissue arachidonic acid content in adults consuming Western-type diets: a systematic review  

PubMed Central

Background Linoleic acid, with a DRI of 12-17 g/d, is the most highly consumed polyunsaturated fatty acid in the Western diet and is found in virtually all commonly consumed foods. The concern with dietary linoleic acid, being the metabolic precursor of arachidonic acid, is its consumption may enrich tissues with arachidonic acid and contribute to chronic and overproduction of bioactive eicosanoids. However, no systematic review of human trials regarding linoleic acid consumption and subsequent changes in tissue levels of arachidonic acid has been undertaken. Objective In this study, we reviewed the human literature that reported changes in dietary linoleic acid and its subsequent impact on changing tissue arachidonic acid in erythrocytes and plasma/serum phospholipids. Design We identified, reviewed, and evaluated all peer-reviewed published literature presenting data outlining changes in dietary linoleic acid in adult human clinical trials that reported changes in phospholipid fatty acid composition (specifically arachidonic acid) in plasma/serum and erythrocytes within the parameters of our inclusion/exclusion criteria. Results Decreasing dietary linoleic acid by up to 90% was not significantly correlated with changes in arachidonic acid levels in the phospholipid pool of plasma/serum (p = 0.39). Similarly, when dietary linoleic acid levels were increased up to six fold, no significant correlations with arachidonic acid levels were observed (p = 0.72). However, there was a positive relationship between dietary gamma-linolenic acid and dietary arachidonic acid on changes in arachidonic levels in plasma/serum phospholipids. Conclusions Our results do not support the concept that modifying current intakes of dietary linoleic acid has an effect on changing levels of arachidonic acid in plasma/serum or erythrocytes in adults consuming Western-type diets.

2011-01-01

441

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

442

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

443

Study of dynamic process of acetic acid induced-whitening in epithelial tissues at cellular level  

NASA Astrophysics Data System (ADS)

Acetic acid, inducing transient whitening (acetowhitening) when applied to epithelial tissues, is a commonly used contrast agent for detecting early cervical cancer. The goals of this research are to investigate the temporal characteristics of acetowhitening process in cervical epithelial tissue at cellular level and develop a clear understanding of the diagnostic information carried in the acetowhitening signal. A system measuring time-resolved reflectance was built to study the rising and decay processes of acetowhitening signal from the monolayered cell cultures of normal and cancerous cervical squamous cells. It is found that the dynamic processes of acetowhitening in normal and cancerous cells are significantly different. The results of this study provide insight valuable to further understand the acetowhitening process in epithelial cells and to encourage the development of an objective procedure to detect the early cervical cancers based on quantitative monitoring of the dynamic process of acetowhitening

Wu, Tao T.; Qu, Jianan Y.; Cheung, Tak Hong; Yim, So Fan; Wong, Yick Fu

2005-06-01

444

Cardiac sympathetic nerve activity during kainic acid-induced limbic cortical seizures in rats.  

PubMed

We sought to define changes in cardiac sympathetic nerve activity that occur during seizures. We studied kainic acid-induced limbic cortical seizures in urethane-anesthetized rats using cardiac sympathetic nerve, blood pressure, and electrocardiography (ECG) recordings. We studied changes in ventilation rate before and during seizures. Cardiac sympathetic nerve activity was increased during limbic cortical seizures. The modest increases were similar to changes induced by nitroprusside infusion. The normal relation of cardiac sympathetic nerve activity to ventilation rate was lost during seizure activity. Changes in cardiac sympathetic nerve activity caused by changes in ventilation rate became unpredictable, and could be extreme. We conclude that the modest changes in cardiac sympathetic nerve activity contribute to the predominantly parasympathetic effects on the heart during limbic cortical seizures and periods of asphyxia. Further, ventilation rate changes might be associated with large sudden increases or decreases in cardiac sympathetic outflow during seizures. PMID:19055488

Hotta, Harumi; Koizumi, Kiyomi; Stewart, Mark

2008-12-04

445

Characterization of acid-induced molten globule like state of ficin.  

PubMed

Effect of pH on the conformational behaviour of ficin (EC 3.4.22.3), a cysteine protease from the latex of Ficus carica was monitored by circular dichroism, fluorescence spectroscopy, ANS binding and hydrodynamic studies. The results obtained from near- and far-UV CD, intrinsic fluorescence and ANS binding studies demonstrate that ficin exhibits the characteristic properties of molten globule at acidic conditions between pH 1.4 and 2.0. Ficin at pH 1.4 retained about approximately 74% secondary structure with a substantial loss of tertiary structure. The acid-induced state was found to have a compact shape as measured by Stokes radius on size exclusion chromatography. PMID:19482042

Devaraj, K B; Kumar, Parigi Ramesh; Prakash, V

2009-05-29

446

Minor Role of Mitochondrial Respiration for Fatty-Acid Induced Insulin Secretion  

PubMed Central

An appropriate insulin secretion by pancreatic beta-cells is necessary to maintain glucose homeostasis. A rise in plasma glucose leads to increased metabolism and an elevated cytoplasmic ATP/ADP ratio that finally triggers insulin granule exocytosis. In addition to this triggering pathway, one or more amplifying pathways—activated by amino acids or fatty acid—enhance secretion by promoting insulin granule recruitment to, and priming at, the plasma membrane. The aim of this study was to clarify the impact of the mitochondrial respiratory activity on fatty acid-induced insulin secretion that was assessed by an extracellular flux analyzer. Treatment of isolated mouse islets with glucose (20 mM) increased insulin secretion 18-fold and correlated with ATP-synthesizing respiration. Furthermore, oxygen consumption rate (OCR) significantly increased by 62% in response to glucose, whereas the addition of palmitate resulted only in a minor increase of OCR at both 2.8 mM (11%) and 20 mM glucose (21%). The addition of palmitate showed a pronounced increase of coupling efficiency (CE) at 2.8 mM glucose but no further insulin secretion. However, treatment with palmitate at 20 mM glucose increased insulin secretion about 32-fold accompanied by a small increase in CE. Thus, fatty acid induced respiration has a minor impact on insulin secretion. Our data clearly demonstrate that fatty acids in contrast to glucose play a minor role for respiration-mediated insulin secretion. In the presence of high glucose, fatty acids contribute partially to amplifying pathways of insulin secretion by further increasing mitochondrial activity in the islets of Langerhans.

Schulz, Nadja; Kluth, Oliver; Jastroch, Martin; Schurmann, Annette

2013-01-01

447

Minor role of mitochondrial respiration for Fatty-Acid induced insulin secretion.  

PubMed

An appropriate insulin secretion by pancreatic beta-cells is necessary to maintain glucose homeostasis. A rise in plasma glucose leads to increased metabolism and an elevated cytoplasmic ATP/ADP ratio that finally triggers insulin granule exocytosis. In addition to this triggering pathway, one or more amplifying pathways-activated by amino acids or fatty acid-enhance secretion by promoting insulin granule recruitment to, and priming at, the plasma membrane. The aim of this study was to clarify the impact of the mitochondrial respiratory activity on fatty acid-induced insulin secretion that was assessed by an extracellular flux analyzer. Treatment of isolated mouse islets with glucose (20 mM) increased insulin secretion 18-fold and correlated with ATP-synthesizing respiration. Furthermore, oxygen consumption rate (OCR) significantly increased by 62% in response to glucose, whereas the addition of palmitate resulted only in a minor increase of OCR at both 2.8 mM (11%) and 20 mM glucose (21%). The addition of palmitate showed a pronounced increase of coupling efficiency (CE) at 2.8 mM glucose but no further insulin secretion. However, treatment with palmitate at 20 mM glucose increased insulin secretion about 32-fold accompanied by a small increase in CE. Thus, fatty acid induced respiration has a minor impact on insulin secretion. Our data clearly demonstrate that fatty acids in contrast to glucose play a minor role for respiration-mediated insulin secretion. In the presence of high glucose, fatty acids contribute partially to amplifying pathways of insulin secretion by further increasing mitochondrial activity in the islets of Langerhans. PMID:24065099

Schulz, Nadja; Kluth, Oliver; Jastroch, Martin; Schürmann, Annette

2013-09-16

448

Aminolaevulinic acid-induced photodynamic therapy: cellular responses to glucose starvation  

PubMed Central

Photodynamic therapy is a cancer treatment based on the interaction of light, oxygen and a photosensitiser. Protoporphyrin. IX is an endogenous photosensitiser derived from the pro-drug aminolaevulinic acid. Tumours contain areas of hypoxia and hypoglycaemia. Tumour cells adapt to these conditions by stress protein induction which may induce resistance to cancer therapies. The effect of chronic hypoglycaemia on sensitivity to aminolaevulinic acid-induced photodynamic therapy in vitro was studied in MCF-7, human breast cancer cells. Following chronic exposure to 0, 1 or 25?mM, glucose, cells were treated with aminolaevulinic acid and the generation of intracellular protoporphyrin. IX measured by spectrofluorimetry. Aminolaevulinic acid-induced photodynamic therapy sensitivity was compared between cells following chronic exposure to 0, 1 or 25?mM glucose. Percentage cell survival was determined by clonogenic assay. Cells cultured in low glucose generated higher levels of protoporphyrin IX compared to standard glucose medium (0?mM glucose: 0.88×10?5?ng?cell?1, 1?mM: 0.86×10?5?ng?cell?1, 25?mM: 0.605×10?5?ng?cell?1, P<0.05). However, photodynamic therapy sensitivity was reduced in glucose deprived cells (0?mM glucose: 61% survival, 1?mM: 80.5% and 25?mM: 39.6%, P<0.05). Chronic exposure to low glucose induces photodynamic therapy resistance despite increased intracellular concentrations of protoporphyrin IX and may reflect cellular adaptation to chronic glucose deprivation. British Journal of Cancer (2002) 86, 1343–1347. DOI: 10.1038/sj/bjc/6600234 www.bjcancer.com © 2002 Cancer Research UK

Wyld, L; Tomlinson, M; Reed, M W R; Brown, N J

2002-01-01

449

GlcNAcylation of a histone methyltransferase in retinoic-acid-induced granulopoiesis.  

PubMed

The post-translational modifications of histone tails generate a 'histone code' that defines local and global chromatin states. The resultant regulation of gene function is thought to govern cell fate, proliferation and differentiation. Reversible histone modifications such as methylation are under mutual controls to organize chromosomal events. Among the histone modifications, methylation of specific lysine and arginine residues seems to be critical for chromatin configuration and control of gene expression. Methylation of histone H3 lysine 4 (H3K4) changes chromatin into a transcriptionally active state. Reversible modification of proteins by beta-N-acetylglucosamine (O-GlcNAc) in response to serum glucose levels regulates diverse cellular processes. However, the epigenetic impact of protein GlcNAcylation is unknown. Here we report that nuclear GlcNAcylation of a histone lysine methyltransferase (HKMT), MLL5, by O-GlcNAc transferase facilitates retinoic-acid-induced granulopoiesis in human HL60 promyelocytes through methylation of H3K4. MLL5 is biochemically identified in a GlcNAcylation-dependent multi-subunit complex associating with nuclear retinoic acid receptor RARalpha (also known as RARA), serving as a mono- and di-methyl transferase to H3K4. GlcNAcylation at Thr 440 in the MLL5 SET domain evokes its H3K4 HKMT activity and co-activates RARalpha in target gene promoters. Increased nuclear GlcNAcylation by means of O-GlcNAc transferase potentiates retinoic-acid-induced HL60 granulopoiesis and restores the retinoic acid response in the retinoic-acid-resistant HL60-R2 cell line. Thus, nuclear MLL5 GlcNAcylation triggers cell lineage determination of HL60 through activation of its HKMT activity. PMID:19377461

Fujiki, Ryoji; Chikanishi, Toshihiro; Hashiba, Waka; Ito, Hiroaki; Takada, Ichiro; Roeder, Robert G; Kitagawa, Hirochika; Kato, Shigeaki

2009-04-19

450

IL-17A Synergistically Enhances Bile Acid-Induced Inflammation during Obstructive Cholestasis.  

PubMed

During obstructive cholestasis, increased concentrations of bile acids activate ERK1/2 in hepatocytes, which up-regulates early growth response factor 1, a key regulator of proinflammatory cytokines, such as macrophage inflammatory protein 2 (MIP-2), which, in turn, exacerbates cholestatic liver injury. Recent studies have indicated that IL-17A contributes to hepatic inflammation during obstructive cholestasis, suggesting that bile acids and IL-17A may interact to regulate hepatic inflammatory responses. We treated mice with an IL-17A neutralizing antibody or control IgG and subjected them to bile duct ligation. Neutralization of IL-17A prevented up-regulation of proinflammatory cytokines, hepatic neutrophil accumulation, and liver injury, indicating an important role for IL-17A in neutrophilic inflammation during cholestasis. Treatment of primary mouse hepatocytes with taurocholic acid (TCA) increased the expression of MIP-2. Co-treatment with IL-17A synergistically enhanced up-regulation of MIP-2 by TCA. In contrast to MIP-2, IL-17A did not affect up-regulation of Egr-1 by TCA, indicating that IL-17A does not affect bile acid-induced activation of signaling pathways upstream of early growth response factor 1. In addition, bile acids increased expression of IL-23, a key regulator of IL-17A production in hepatocytes in vitro and in vivo. Collectively, these data identify bile acids as novel triggers of the IL-23/IL-17A axis and suggest that IL-17A promotes hepatic inflammation during cholestasis by synergistically enhancing bile acid-induced production of proinflammatory cytokines by hepatocytes. PMID:24012680

O'Brien, Kate M; Allen, Katryn M; Rockwell, Cheryl E; Towery, Keara; Luyendyk, James P; Copple, Bryan L

2013-09-05

451

Curcumin restores Nrf2 levels and prevents quinolinic acid-induced neurotoxicity.  

PubMed

Neurological diseases comprise a group of heterogeneous disorders characterized by progressive brain dysfunction and cell death. In the next years, these diseases are expected to constitute a world-wide health problem. Because excitotoxicity and oxidative stress are involved in neurodegenerative diseases, it becomes relevant to describe pharmacological therapies designed to activate endogenous cytoprotective systems. Activation of transcription factor Nrf2 stimulates cytoprotective vitagenes involved in antioxidant defense. In this work, we investigated the ability of the antioxidant curcumin to induce transcription factor Nrf2 in a neurodegenerative model induced by quinolinic acid in rats. Animals were administered with curcumin (400 mg/kg, p.o.) for 10 days, and then intrastriatally infused with quinolinic acid (240 nmol) on day 10 of treatment. Curcumin prevented rotation behavior (6 days post-lesion), striatal morphological alterations (7 days post-lesion) and neurodegeneration (1 and 3 days post-lesion) induced by quinolinic acid. Curcumin also reduced quinolinic acid-induced oxidative stress (measured as protein carbonyl content) at 6 h post-lesion. The protective effects of curcumin were associated to its ability to prevent the quinolinic acid-induced decrease of striatal intra-nuclear Nrf2 levels (30 and 120 min post-lesion), and total superoxide dismutase and glutathione peroxidase activities (1 day post-lesion). Therefore, results of this study support the concept that neuroprotection induced by curcumin is associated with its ability to activate the Nrf2 cytoprotective pathway and to increase the total superoxide dismutase and glutathione peroxidase activities. PMID:22704781

Carmona-Ramírez, Iván; Santamaría, Abel; Tobón-Velasco, Julio C; Orozco-Ibarra, Marisol; González-Herrera, Irma G; Pedraza-Chaverrí, José; Maldonado, Perla D

2012-06-15

452

Montelukast potentiates the protective effect of rofecoxib against kainic acid-induced cognitive dysfunction in rats.  

PubMed

There is an evolving consensus that mild cognitive impairment (MCI) serves as a prodrome to Alzheimer's disease. Antioxidants and COX-2 (cyclo-oxygenase-2) inhibitors have also been reported to have beneficial effects against conditions of memory impairment. Newer drugs like cysteinyl leukotriene inhibitors have shown neuroprotective effect in animal models of ischemia. Thus, the present study purports to explore the potential role of montelukast (a cysteinyl leukotriene inhibitor) in concert with rofecoxib (COX-2 inhibitor) and caffeic acid (a 5-LOX inhibitor and potent antioxidant) against kainic acid induced cognitive dysfunction in rats. In the experimental protocol, kainic acid (0.4 ?g/2 ?l) in artificial cerebrospinal fluid (ACSF) was given intrahippocampally (CA3 region) to induce a condition similar to MCI. Memory performance was measured on days 10-14 and the locomotor activity was measured on days 1, 7 and 14. For estimation of biochemical, mitochondrial and histopathological parameters, animals were sacrificed on day 14, stored at -80 °C and the estimation was done on the 15th day. The treatment groups consisting of montelukast (0.5 and 1 mg/kg), rofecoxib (5 and 10 mg/kg) and caffeic acid (5 and 10 mg/kg) showed significant improvement in memory performance, oxidative stress parameters and mitochondrial function as compared to that of control (kainic acid treated), however, combination of montelukast with rofecoxib showed significant improvement in their protective effect. Thus the present study emphasizes the positive modulation of cysteinyl leukotriene receptor inhibition on COX (cyclooxygenase) and LOX (lipoxygenase) pathways in the control of the neuroinflammation in kainic acid induced cognitive dysfunction in rats. PMID:22878042

Kumar, Anil; Prakash, Atish; Pahwa, Deeksha; Mishra, Jitendriya

2012-11-01

453

Differences in responsiveness of intrapulmonary artery and vein to arachidonic acid: mechanism of arterial relaxation involves cyclic guanosine 3':5'-monophosphate and cyclic adenosine 3':5'-monophosphate  

Microsoft Academic Search

The objective of this study was to examine the relationship between responses of bovine intrapulmonary artery and vein to arachidonic acid and cyclic nucleotide levels in order to better understand the mechanism of relaxation elicited by arachidonic acid and acetylcholine. Arachidonic acid relaxed phenylephrine-precontracted arterial rings and elevated both cyclic GMP and cyclic AMP levels in arteries with intact endothelium.

L. J. Ignarro; R. G. Harbison; K. S. Wood; M. S. Wolin; D. B. McNamara; A. L. Hyman; P. J. Kadowitz

1985-01-01

454

Manufacturing and in vivo inner ear visualization of MRI traceable liposome nanoparticles encapsulating gadolinium  

Microsoft Academic Search

BACKGROUND: Treatment of inner ear diseases remains a problem because of limited passage through the blood-inner ear barriers and lack of control with the delivery of treatment agents by intravenous or oral administration. As a minimally-invasive approach, intratympanic delivery of multifunctional nanoparticles (MFNPs) carrying genes or drugs to the inner ear is a future therapy for treating inner ear diseases,

Jing Zou; Rohit Sood; Sanjeev Ranjan; Dennis Poe; Usama A Ramadan; Paavo KJ Kinnunen; Ilmari Pyykkö

2010-01-01

455

Ear segmentation using histogram based K-means clustering and Hough transformation under CVL dataset  

Microsoft Academic Search

Under CVL dataset, we provide an image segmentation approach based on adaptive histogram based K-means clustering and fast Hough transformation. This work firstly analyzes the characteristics of ear images in CVL face dataset. According to the analysis, we then use adaptive histogram based K-means clustering method to threshold ear images and then roughly segment the ear parts. After ear contour

Heng Liu; Dekai Liu

2009-01-01

456

Potassium Ion Movement in the Inner Ear: Insights from Genetic Disease and Mouse Models  

Microsoft Academic Search

The ear detects sound waves, which are pressure varia- tions in air (FIGURE 1). Sound enters the outer ear and sets the tympanic membrane in motion. Motions are conducted by middle ear bones to the oval window, from where they enter the fluid-filled cochlea of the inner ear. These \\

Anselm A. Zdebik; Philine Wangemann; Thomas J. Jentsch

2009-01-01

457

Scientific Investigations on the Red-Eared Turtle, 'Trachemys scripta elegans'. Long Term Resource Monitoring Program.  

National Technical Information Service (NTIS)

Contents: Melanism in the Red-eared Slider (Trachemys scripta elegans); Salvage of Eggs from Road-killd Red-eared Sliders, Trachemys scripta elegans; Unusual Coloration in a Red-eared Slider, Trachemys scripta elegans; Fences and Nesting Red-eared Sliders...

J. K. Tucker F. A. Cronin B. J. Kerans N. I. Filoramo F. J. Janzen G. L. Paukstis C. H. Theiling D. Moll R. J. Maher

1997-01-01

458

An Improved Model of Mechanical Neural Transduction in the Cochlea, the Robinson Ear Model 2  

Microsoft Academic Search

The Robinson Ear Model 2, an improved version of the original Robinson ear model, is presented. The Robinson ear model is based on the anatomy of the cochlea and the theory that sound induced neural firings are stimulated by the interaction of two waves, a pressure wave moving through the fluid of the inner ear at the speed of sound

Raymond Melvin Warner Jr.

1990-01-01

459

Building and Testing a Statistical Shape Model of the Human Ear Canal  

Microsoft Academic Search

Today the design of custom in-the-ear hearing aids is based on personal experience and skills and not on a systematic description of the variation of the shape of the ear canal. In this paper it is described how a dense surface point distribution model of the human ear canal is built based on a training set of laser scanned ear

Rasmus Paulsen; Rasmus Larsen; Claus Nielsen; Søren Laugesen; Bjarne K. Ersbøll

2002-01-01

460

Summary From the Ear, Nose, And Throat Devices Panel ...  

Center for Biologics Evaluation and Research (CBER)

... Implantable Middle Ear Hearing Devices (IMEHD). ... For adults (>=18 yrs) with moderate to severe Sensorineural hearing loss (SNHL) desiring an ... More results from www.fda.gov/advisorycommittees/committeesmeetingmaterials/medicaldevices

461

Ensemble training to improve recognition using 2D ear  

NASA Astrophysics Data System (ADS)

The ear has gained popularity as a biometric feature due to the robustness of the shape over time and across emotional expression. Popular methods of ear biometrics analyze the ear as a whole, leaving these methods vulnerable to error due to occlusion. Many researchers explore ear recognition using an ensemble, but none present a method for designing the individual parts that comprise the ensemble. In this work, we introduce a method of modifying the ensemble shapes to improve performance. We determine how different properties of an ensemble training system can affect overall performance. We show that ensembles built from small parts will outperform ensembles built with larger parts, and that incorporating a large number of parts improves the performance of the ensemble.

Middendorff, Christopher; Bowyer, Kevin W.

2009-05-01

462

Making an Effort to Listen: Mechanical Amplification in the Ear  

PubMed Central

The inner ear’s performance is greatly enhanced by an active process defined by four features: amplification, frequency selectivity, compressive nonlinearity, and spontaneous otoacoustic emission. These characteristics emerge naturally if the mechanoelectrical transduction process operates near a dynamical instability, the Hopf bifurcation, whose mathematical properties account for specific aspects of our hearing. The active process of non-mammalian tetrapods depends upon active hair-bundle motility, which emerges from the interaction of negative hair-bundle stiffness and myosin-based adaptation motors. Taken together, these phenomena explain the four characteristics of the ear’s active process. In the high-frequency region of the mammalian cochlea, the active process is dominated instead by the phenomenon of electromotility, in which the cell bodies of outer hair cells extend and contract as the protein prestin alters its membrane surface area in response to changes in membrane potential.

Hudspeth, A. J.

2009-01-01

463

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- ...

464

FDA Questions for the Ear, Nose, and Throat Devices Advisory ...  

Center for Biologics Evaluation and Research (CBER)

Text VersionDraft FDA Questions for the Ear, Nose, and Throat Devices Advisory Panel December 18, 2009 P090018 Esteem® Totally Implantable Hearing ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

465

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

2013-09-03

466

Transitional mammalian middle ear from a new Cretaceous Jehol eutriconodont.  

PubMed

The transference of post-dentary jaw elements to the cranium of mammals as auditory ossicles is one of the central topics in evolutionary biology of vertebrates. Homologies of these bones among jawed vertebrates have long been demonstrated by developmental studies; but fossils illuminating this critical transference are sparse and often ambiguous. Here we report the first unambiguous ectotympanic (angular), malleus (articular and prearticular) and incus (quadrate) of an Early Cretaceous eutriconodont mammal from the Jehol Biota, Liaoning, China. The ectotympanic and malleus have lost their direct contact with the dentary bone but still connect the ossified Meckel's cartilage (OMC); we hypothesize that the OMC serves as a stabilizing mechanism bridging the dentary and the detached ossicles during mammalian evolution. This transitional mammalian middle ear narrows the morphological gap between the mandibular middle ear in basal mammaliaforms and the definitive mammalian middle ear (DMME) of extant mammals; it reveals complex changes contributing to the detachment of ear ossicles during mammalian evolution. PMID:21490668

Meng, Jin; Wang, Yuanqing; Li, Chuankui

2011-04-14

467

A Study of Evoked Potentials From Ear-EEG.  

PubMed

A method for brain monitoring based on measuring the electroencephalogram (EEG) from electrodes placed in-the-ear (ear-EEG) was recently proposed. The objective of this study is to further characterize the ear-EEG and perform a rigorous comparison against conventional on-scalp EEG. This is achieved for both auditory and visual evoked responses, over steady-state and transient paradigms, and across a population of subjects. The respective steady-state responses are evaluated in terms of signal-to-noise ratio and statistical significance, while the qualitative analysis of the transient responses is performed by considering grand averaged event-related potential (ERP) waveforms. The outcomes of this study demonstrate conclusively that the ear-EEG signals, in terms of the signal-to-noise ratio, are on par with conventional EEG recorded from electrodes placed over the temporal region. PMID:23722447

Kidmose, Preben; Looney, David; Ungstrup, Michael; Rank, Mike Lind; Mandic, Danilo P

2013-05-29

468

The Acoustic Impedance of the Ear - Summary by the Moderator.  

National Technical Information Service (NTIS)

The absolute impednace can be measured at the eardrum under normal conditions, with a pressure differential across the eardrum, or with contracted middle ear muscles. It is also possible to use impedance changes due to muscle reflexes or pressure changes ...

J. Zwislocki

1965-01-01

469

Groovy flow patterns in the fish ear  

NASA Astrophysics Data System (ADS)

The dense, bony otoliths contained in the fish ear oscillate with respect to their surrounding tissue and endolymph in the presence of sound waves. How an otolith actually transduces this acoustically induced fluid motion into the hair cell displacements that the fish ``hears'' is not fully understood, however. The fluid flow created by the oscillation of the irregularly shaped otolith has both steady and unsteady components. Since most of the hair cells are next to a grooved area on the otolith, the sulcus, the otolith was modeled as a grooved spheroid oscillating in a quiescent Newtonian fluid. Particle-image velocimetry and pathline visualizations for the steady streaming flows within the groove are presented for oscillation at 0 --90 with respect to the body axis of symmetry Re=2?f,^2/?=O(10-10^2), and ?=s/L 0.025-0.05. Here, ? is the fluid kinematic viscosity, L is a typical length based on the spheroid, and f and s are the oscillation frequency and amplitude, respectively. Results for bodies oscillated by multiple frequencies f1 and f2 along the same direction imply that the velocity fields are the superposition of those due to the component frequencies for small values of ?.

Kotas, Charlotte W.; Rogers, Peter H.; Yoda, Minami

2007-11-01

470

Experimental evidence against middle ear oxygen absorption.  

PubMed

The present theory of eustachian tube (ET) function and middle ear (ME) ventilation posits that oxygen absorbed by the ME mucosa causes negative ME pressure which is relieved by periodic opening of the ET during swallowing and yawning. After developing a method to cannulate the ET of mongrel dogs we connected the cannulas hermetically to manometers. This system excluded ET function and tested the oxygen absorption capacity of the ME. When we controlled respiration and maintained blood gas PO2 and PCO2 at normal levels, we were unable to find any manometric evidence of negative pressure of gas absorption in the dog ME. Lowering the PCO2 and raising the PO2 of the blood by hyperventilation caused negative ME pressure which could be measured manometrically. We confirmed these findings with the tympanometer. Raising the PCO2 and lowering the PO2 by hypoventilation caused positive pressure in the ME. There is no evidence in these experiments that O2 absorption occurs or causes negative ME pressure in the dog. To the contrary there is evidence that elevated blood levels of the more diffusible CO2 cause an increase in the ME pressure and lowered CO2 level causes a negative ME pressure. PMID:3920459

Buckingham, R A; Stuart, D R; Geick, M R; Girgis, S J; McGee, T J

1985-04-01

471

Penetration of ceftibuten into middle ear fluid.  

PubMed Central

The penetration of ceftibuten, an extended-spectrum oral cephalosporin, into middle ear fluid (MEF) was evaluated in pediatric patients during a course of daily oral doses of 9 mg/kg of body weight for 10 days. Plasma and MEF collected at 2, 4, 6, or 12 h after at least 3 days of dosing were analyzed for ceftibuten by a high-pressure liquid chromatography method, and the data were used to calculate pharmacokinetic parameters. Plasma