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Biomedical subjects

Y Zohar

Publications and source records attributed to Y Zohar.

At least 73 records · Page 4Linked to original sources
PubMed1992

In vitro bioactivities of various forms of GnRH in relation to their susceptibility to degradation at the pituitary level in the rainbow trout, Oncorhynchus mykiss.

In vitro potencies of native and modified forms of salmon and mammalian gonadotropin-releasing hormone (GnRH) were studied in relation with their susceptibility to degradation by intact pituitary cells maintained in culture. The kinetics of degradation and the origin of the proteases involved in this process were examined. All the molecules tested (native and modified forms) were equipotent at doses between 10(-6) and 10(-7) M in inducing GtH release by cultured pituitary cells. On the other hand, their effectiveness differed at 10(-9) and 10(-8) M leading to the establishment of the following hierarchy of bioactivity: the native forms, LHRH and sGnRH, were the less potent, the fish analogues (DAla6Pro9Net)sGnRH and (DArg6Pro9Net)sGnRH were the more potent, and mammalian analogues with substitutions at position 6 and/or 10 were intermediate in potency. The native form sGnRH was weakly degraded while no degradation of the modified molecules was observed. The degradation of the native sGnRH occurred after 12 and 24 hr of incubation and the results indicate that the peptidases involved are released from the cells into the incubation medium.

Animals↗
PubMed1992

Occult and overt submucous cleft palate: from peroral examination to nasendoscopy and back again.

Peroral examination of the soft palate is of greater value than generally recognized. The nasendoscopic examination provides essential information on the velopharyngeal valve physiology and pathology. However, nasendoscopy cannot be performed in individuals who are uncooperative such as young children, patients with personality disturbances or those mentally retarded, or in the presence of severe deformity of the nose. In these patients the peroral examination is of particular practical clinical application. Forty cases of occult and overt submucous cleft palate were included in the present study. We describe the contribution of systematic assessment of the soft palate intraorally, based on a correlation with nasendoscopic examination of the velopharyngeal valve in speech. An accurate peroral examination can provide additional information on abnormality of the velar musculature as well as the existence of Passavant's ridge. This information is particularly important in children who are too young for nasendoscopix examination, but because of their poor speech intelligibility, early diagnosis and treatment are imperative.

Adolescent↗
PubMed1992

Characterization of gonadotropin-releasing hormone binding to pituitary receptors in the gilthead seabream (Sparus aurata).

Receptors for GnRH in the pituitary of Sparus aurata were characterized using iodinated [D-Ala6-Pro9-NEt]-LHRH (GnRHa). Equilibrium binding of the ligand to the receptor was achieved after 1 h at 4 degrees C. Binding of the radioligand was a function of tissue concentration, with a linear correlation over the range of one-sixteenth to three-fourths pituitary per tube. Displacement experiments with salmon GnRH (sGnRH), GnRHa, as well as unrelated peptides demonstrated the specificity of the receptors. Binding was found to be saturable at ligand concentrations of 4 x 10(-9) M. Scatchard analysis of the saturation data suggested the presence of a single class of high-affinity sites (Ka = 0.567 +/- 0.136 x 10(9) M-1, Bmax = 1091 +/- 207 fmol/mg protein).

Animals↗
PubMed1992

On the variability of velopharyngeal valve anatomy and function: a combined peroral and nasendoscopic study.

The oropharynx stripped of the tonsils and the excessive mucosal folds after the uvulopalatopharyngoplasty operation allows a closed observation of the outline of the pharyngeal muscles. Forty-two consecutive patients undergoing uvolopalatopharyngoplasty were subjected to peroral examination of the oropharynx combined with nasendoscopic examination of the velopharyngeal valve. At rest, the oropharynx of the patients with coronal closure patterns was found to be flat relative to the oropharynx of the patients with the other closure patterns. During closure of the velopharyngeal valve, an anteroposterior movement of the velum, forming the nasendoscopic coronal closure pattern, was observed in patients with a flat oropharynx. On the other hand, a medial movement of the pharyngeal walls was found, forming the circular or sagittal closure pattern seen in patients with a deep oropharynx. Our conclusion is therefore that a different muscular orientation is responsible for both the different pharyngeal configuration at rest and the different contribution of the lateral and posterior pharyngeal walls to velopharyngeal valve closure.

Adult↗
PubMed1992

Cardiac function in obstructive sleep apnea patients following uvulopalatopharyngoplasty.

Obstructive sleep apnea syndrome (OSAS) is associated with severe cardiac arrhythmias and conduction abnormalities. Cor pulmonale and right-sided heart failure may ensue. Uvulopalatopharyngoplasty (UPPP) is one of several treatment modalities suggested for OSAS. Tracheotomy and CPAP treatment in adult OSAS patients and adenotonsillectomy in children with OSAS were shown to lead to improvement in some cardiac parameters. Cardiac function was prospectively evaluated in 19 OSAS patients before and after UPPP. No significant changes after surgery were noted on electrocardiographic studies. Improvement in global and regional function of both ventricles was seen in 91% of the patients. A trend toward significant elevation in left ventricular ejection fraction and a statistically significant increase in right ventricular ejection fraction were observed (45% +/- 9% to 50% +/- 7% [p = 0.007]). Our results support performance of UPPP in selected OSAS patients for relief of potentially life-threatening cardiac pathologies.

Adult↗
PubMed1992

The riddle of the uvula.

Since ancient times, the uvula has been a subject of interesting and contradictory observations. On the one hand, it was regarded as having a functional role in speech and in immunology, but on the other hand it was regarded as a potentially hazardous organ, possibly responsible for sudden infant death syndrome. None of these hypotheses, however, has been proved. In a previous study on patients undergoing uvulopalatopharyngoplasty, we suggested that the most important function of the uvula is connected with the muscularis uvula. Its function could be related to drinking while bending over. This previous assumption was that the uvula is a phylogenetic remnant from mammals that drink while bending their neck downward. In the present study, the soft palate of eight different mammals was macroscopically and microscopically studied and compared. Of all animals in the study, a small underdeveloped uvula was found only in two baboons. We found that the human uvula consists of an intermix of serous and seromucous glandular masses, muscular tissue, and large excretory canals. The serous and seromucous glands are absent in the other mammals. Thus, the uvula is a highly sophisticated structure, capable of producing a large quantity of fluid saliva that can be excreted in a short time. Both uvula and speech serve to differentiate human beings from animals. Our conclusion is that the uvula is possibly an accessory organ of speech, and may be another marker of human evolution that differentiates man from other mammals.

Animals↗
PubMed1992

The controversial treatment of anterior commissure carcinoma of the larynx.

There are two basic approaches to the appropriate therapy for carcinoma of the anterior commissure. The dilemma of whether to treat by primary irradiation or by conservative surgery is not yet solved. In this study, 67 patients were treated between 1967 and 1987 for anterior commissure carcinoma of the larynx. Radiation was used with 47 patients and conservation surgery with 20 patients. Initial lesion control was achieved with 72% of the patients treated by primary irradiation. Conservation surgery, when used as a primary treatment modality, achieved local control in 90% of the patients. The new techniques of reconstruction of the larynx enhance the surgeon's ability, strengthen his conviction to proceed to enlarged partial laryngectomies, and thus improve the oncologic control of the anterior commissure carcinoma as well.

Carcinoma, Squamous Cell↗
PubMed1992

Effects of acute negative middle ear pressure on hearing. New answers to old questions and a review of the literature.

The magnitude of hearing loss caused by negative middle ear pressure is a controversial issue. We present a clinical, prospective and controlled study on the effect of negative middle ear pressure on hearing in human ears. Sixty-two ears of patients undergoing uvulopalatopharyngoplasty were examined pre- and postoperatively. The test group consisted of 31 ears in which negative postoperative middle ear pressure ranging between -150 and -400 mmH2O had developed. The control group consisted of 31 ears in which no middle ear pressure change was recorded after the same operation. Bone conduction hearing loss up to 20 dB (with a mean of 11 dB) at 250 Hz, up to 25 dB (with a mean of 13.1 dB) at 500 Hz and up to 10 dB (with a mean of 7.6) at 1,000 Hz was the dominant finding. An additional air-bone gap up to 15 dB (with a mean of 4.3 dB) was found only at 250 Hz. Basic theories about the acoustic response of the ear are discussed and new theories proposed.

Adult↗
PubMed1992

Auditory brainstem evoked response in patients undergoing carotid endarterectomy.

Auditory brainstem evoked response-(ABR) may be affected by changes in cerebral blood flow. Apart from its primary indications for prevention of stroke and transient ischemic attacks-(TIA's), internal carotid endarterectomy-(ICE) has been shown to improve cognitive function and cause diminution of tinnitus and vertigo. A one-week postoperative ABR previous study of patients undergoing ICE demonstrated no change in ABR recordings. In order to evaluate possible late changes, we have conducted a prospective study of the delayed effects of ICE on ABR in 13 patients. No initial pathology was noted and no significant change found in any of the absolute and interpeak latencies of ABR waves.

Acoustic Stimulation↗
PubMed1991

X-ray microanalysis of ossified auricles in Addison's disease.

The element content of ossified auricles in two patients with Addison's disease was determined by X-ray microanalysis. The results showed a similar element content of the ossified auricles of the Addison's patients and control bone specimens. The calcium and phosphorus content of the petrified auricles was, however, slightly decreased compared with the iliac bone biopsies of the patients. The sulfur content of the ossified auricles was higher than that of their bones, but markedly lower than control auricular cartilage. Iron, sodium, and chloride contents were similar in the ossified auricles and in the normal auricular cartilage, whereas only trace amounts of these elements were detected in the bone. The auricles of the patients with Addison's disease possessed relatively high aluminium content compared with both control bone and cartilage. The element content of the bone biopsies from Addison patients was comparable to control bone. The presence of trace amounts of aluminium in the petrified auricles of Addison's patients is probably attributed to a long period of aluminium hydroxide consumption.

Addison Disease↗
PubMed1991

Squamous and basal cell cancers directly invading major salivary glands.

Epidermoid carcinoma of the skin of the head and neck may uncommonly involve the parotid gland by either direct extension or metastases to the parotid lymph nodes. The parotid gland contains a rich network of superficial and deep nodes, draining a large area of the facial region, with the preauricular, cheek, ear, and eyelid dominating. Few patients with direct parenchymal invasion of the parotid gland by a simultaneously existing squamous or basal cell carcinoma were reported. We could find no report discussing direct tumoral invasion into the submandibular salivary gland. Three patients with squamous cell carcinomas and 2 with basal cell carcinomas of the skin directly involving the underlying salivary glands are presented. The few authors discussing this subject concur that treatment should include resection of the primary tumor along with parotidectomy. Elective neck dissection and irradiation are proposed. The course of disease, treatment, and survival of our patients are discussed.

Adult↗
PubMed1991

Syndrome of inappropriate antidiuretic hormone secretion in cancer of the head and neck.

The syndrome of inappropriate secretion of arginine vasopressin (AVP) known as the syndrome of inappropriate antidiuretic hormone secretion (SIADH) is characterized by hyponatremia that results from water retention attributable to persistent AVP release. It may occur in a variety of malignant and nonmalignant lesions, with small cell or oat cell carcinoma of the lung by far responsible for the largest number of these cases. Cancer of the head and neck may be a rare cause of SIADH, and only a few such cases have been reported. We describe four patients with advanced cancer of the head and neck region with coexisting SIADH. Diagnosis and treatment are reported and the literature is reviewed. The possible occurrence of SIADH in the head and neck surgical practice should be kept in mind. Since SIADH is usually transient, water restriction and parenteral sodium chloride may be sufficient in overcoming the acute phase.

Adult↗
PubMed1991

Uvulopalatopharyngoplasty: evaluation of postoperative complications, sequelae, and results.

A study of 71 patients with obstructive sleep apnea syndrome was performed to evaluate the effectiveness, complications, and late sequelae of uvulopalatopharyngoplasty. Postoperative immediate complications were of minor importance. In 96% of the patients, the snoring was improved; it was completely resolved in 48%. The postoperative apnea index remained pathologic in all patients who underwent postoperative polysomnography, although mild improvement was noted. Seventy-four percent of our patients felt a subjective postoperative improvement which was not always confirmed by the polysomnographic examination. A record of improvement was obtained in 64% of the operated patients. Our results establish the beneficial effect of uvulopalatopharyngoplasty, which is the recommended surgical procedure for obstructive sleep apnea syndrome.

Adult↗
PubMed1991

Study of the normal and insufficient velopharyngeal valve by the "Forced Sucking Test".

A thorough assessment of the velopharyngeal (VP) closure dynamics is important for therapeutic planning in patients with nasal speech. An additional diagnostic tool to the standard endoscopic examination of the VP valve, the "Forced Sucking Test" (FST) is presented. In this study, 110 patients with a normal VP valve and 40 patients with VP insufficiency were subjected to a comprehensive endoscopic examination. When existent, Passavant's ridge clearly appears in 80% of these cases during the FST. This is advantageous, since the ridge is often unseen during routine nasendoscopy. Passavant's ridge appears indistinguishable in shape and level during speech and FST. During FST, the bulge of the uvular ridge is clearly seen on the flat or concave nasal surface of the velum. In cases of diastasis of the velar musculature, the midline V-defect of the velum is clearly seen. The test is particularly important in children with concomitant adenoid hypertrophy. The findings are discussed in terms of their implications for the anatomy and physiology of the VP valve. FST is recommended as an additional and complementary part of the endoscopic examination of the VP valve.

Adult↗
PubMed1991

Barotrauma-induced hearing loss.

With the current increase in commercial, military and sports diving to deeper depths, cases of middle and inner ear barotrauma are more frequently noted. Although most of the literature up to the late 1960s has emphasized middle ear barotrauma (MEBT), inner ear barotrauma (IEBT) is reported more frequently than before. MEBT and IEBT are major causes of diving induced hearing loss. MEBT should be treated by prevention and symptomatically when occurring. A labyrinthine window fistula necessitating surgical repair may be caused by IEBT. Although reports of IEBT are relatively few, this entity should be kept in mind and differentiated from other causes of diving-induced hearing loss. The relevant literature is reviewed and diagnosis and treatment are discussed.

Atmospheric Pressure↗
PubMed1991

Decompression sickness induced hearing loss. A review.

Otologic manifestations of decompression sickness (DCS) occur only rarely. However, with more frequent exposures to deeper depths in recent years, several reports of hearing loss due to DCS have appeared. Nevertheless, the scant literature directly discussing the subject establishes otologic DCS as an important cause of diving-induced hearing loss. When hearing impairment with or without vestibular symptoms is a solitary manifestation of DCS type II, it may be difficult to distinguish from middle and inner ear barotrauma resulting in labyrinthine window fistula. Once a diagnosis is established, immediate recompression treatment with hyperbaric oxygen may result in complete recovery. The pathologic mechanism is discussed and the pertinent literature reviewed.

Atmospheric Pressure↗