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Biomedical subjects

I Amir

Publications and source records attributed to I Amir.

16 recordsLinked to original sources
PubMed1997

Bruxism secondary to antipsychotic drug exposure: a positive response to propranolol.

We present two cases of acute nocturnal bruxism occurring as an early side effect of antipsychotic drug treatment. The development of bruxism was coupled with the appearance of neuroleptic-induced akathisia. Both complications were relieved after the beta-adrenergic blocker propranolol was added, suggesting the involvement of the adrenergic and serotonergic central nervous systems, besides the dopaminergic system, in the pathogenesis of bruxism. The positive response of iatrogenic bruxism to propranolol implies that propranolol also deserves a trial for the treatment of noniatrogenic nocturnal bruxism.

Adrenergic beta-Antagonists↗
PubMed1997

Recurrent toxic delirium in a patient treated with SSRIs: is old age a risk factor?

We present the case of a 71-year-old female suffering from bipolar affective disorder type 2 and an old lacunar brain infarct who, under the combined treatment of fluoxetine for depression and low dose trazodone for the accompanying insomnia, developed a toxic delirium. The subject presented with mental state changes (confusion and agitation), hyperreflexia, diaphoresis, nausea, vomiting, fever, and a general tonic-clonic seizure which developed soon after an increase in the trazodone dose. One year prior to the above episode, she was hospitalized for a transient episode of agitated confusion while being treated with fluvoxamine for depression, alprazolam and brotazolam for the accompanying anxiety and insomnia. Both episodes subsided spontaneously when treatment was discontinued. This case reports the possible existence of increased vulnerability to hyperserotonergic states in elderly patients suffering from concomitant psychiatric and neurological disorders.

Age Factors↗
PubMed1996

Ranitidine increases the bioavailability of imbibed alcohol by accelerating gastric emptying.

To investigate the mechanism of the increase in alcohol bioavailability by ranitidine, we determined by nuclear scan the changes in gastric emptying of a 10% ethanol solution (containing 0.3 g ethanol/kg body weight and 300 microCi of technetium-labeled diethylene triamine pentacetic acid) in 8 normal men, before and after treatment with 300 mg ranitidine orally each evening for 1 week. We compared these changes with those of ethanol bioavailability, calculated by integration of the Michaelis-Menten function over the entire alcohol curves after random i.v. and, on a separate day, oral administration of the same ethanol dose, pre- and post-ranitidine. With ranitidine, we found an acceleration of gastric emptying in 7 of 8 subjects, with 20% shortening of the time to 50% emptying (51.8 +/- 4.1 min vs 64.3 +/- 3.4, without ranitidine; P < .001 by paired t test). Despite the disappearance (from the stomach) of most of the dose by the end of the blood alcohol curves, only 83 +/- 4% reached the systemic blood vs 64 +/- 4% without ranitidine (P < .02), most likely because of a shortened exposure of alcohol dehydrogenase to optimal ethanol concentrations. As a result, after oral but not intravenous alcohol administration, ranitidine increased blood alcohol concentrations (29 +/- 4 mg/dl vs 22 +/- 3, without ranitidine; P < .02), with a corresponding decrease in first pass metabolism of ethanol from 107 +/- 16 mg/kg to 47 +/- 16 (P < .01).

Adult↗
PubMed1993

Role of glucocorticoids in the regulation of brain prostaglandin biosynthesis under basal conditions and in response to endotoxin.

Glucocorticoids (GC) are known to inhibit eicosanoid production in various peripheral tissues; however, their role in the regulation of basal and induced prostaglandin (PG) biosynthesis in the brain is still not clear. In the present study we examined the effect of exogenous dexamethasone (dex) or endogenous GC on basal and on bacterial endotoxin (lipopolysaccharide, LPS) induced ex vivo production of PGE2 by the frontal cortex of rat brain. The experimental groups were: 1) intact rats; 2) rats in whom endogenous GC were removed either by surgical or by chemical (metopirone) adrenalectomy (adex); and 3) rats exposed to specific corticosteroid receptor antagonists. In intact rats, the basal rate of PGE2 ex vivo synthesis was about 120 pg/mg protein.hr; dex (0.05-0.5 mg/100 g body wt ip) did not affect this level. Exposure to LPS (50 micrograms, intracerebroventricular) induced a 2-fold increase in PGE2, whereas pretreatment with dex abolished this increase. Bilateral adex or metopirone alone did not change PGE2 synthesis, whereas LPS administration to surgical or chemical adex rats resulted in a 4-fold increase in PGE2 production. Administration (intracerebroventricular) of either one or both of the specific corticosteroid receptor antagonists, RU-28318 (type I) and RU-38486 (type II) did not affect basal PGE2 production. When LPS was given after either one of these antagonists, a slight but significant elevation of PGE2 occurred, as compared to LPS-treated controls. When both antagonists were coadministered, the LPS-induced production of PGE2 was much more pronounced, similar to levels of LPS-treated, adex rats. These results suggest that LPS-induced production of PGE2, but not the basal production, is regulated by either endogenous or exogenous GC, and the inhibitory effect of GC on brain PG synthesis is mediated via both type I and II corticosteroid receptors.

Adrenalectomy↗
PubMed1989

Effect of Na + flux inhibitors on induction of c-fos, c-myc, and ODC genes during cell cycle.

The role of Na + transport systems in the mitogenic signal induced by growth factors was studied, and it was shown that two Na + transport systems contribute to the early increase in cytoplasmic Na + in response to serum growth factors, namely the amiloride-sensitive Na+/H+ antiport and the bumetanide-sensitive Na+/K+/Cl- cotransport. Bumetanide or amiloride, when added separately, inhibited part of the increase in cytoplasmic Na +, as a response to the addition of serum to quiescent BALB/c mouse 3T3 fibroblasts. Each drug also suppressed part of the stimulation of the ouabain-sensitive Rb + influx, which was controlled by intracellular Na +. However, when both drugs were added together with serum growth factors, a complete inhibition of the early increase in [Na +], and subsequently a complete blockage of Na+/K+ pump stimulation was obtained. Amiloride or bumetanide, when added separately, only partially inhibited DNA synthesis induced by serum, 24% and 8% respectively. However, when both drugs were added together, at the time of serum addition to the quiescent cells, cell entry into S-phase was completely inhibited. To investigate the mode of cell-cycle inhibition, analysis was done of the possible role of early Na + fluxes in the mitogenic signal transduced from cell membrane receptors to the nucleus. The effects of the two drugs amiloride and bumetanide on induction of three genes--c-fos, c-myc, and ornithin decarboxylase (ODC)--was measured during cell transition through the G1-phase. Amiloride and bumetanide, when added separately or in combination, did not inhibit the induction of c-fos, c-myc, and ODC mRNAs. These results suggest that stimulation of Na + fluxes by serum growth factors is essential for cell transition into the S-phase of cell cycle, but it plays no apparent role in the growth factor signal transduced from the cell surface to the interior of the cell, as manifested by c-fos, c-myc, and ODC genes induction.

Amiloride↗
PubMed1986

Fibroblast growth factor induces a transient net K+ influx carried by the bumetanide-sensitive transporter in quiescent BALB/c 3T3 fibroblasts.

The bumetanide-sensitive transport system performed a net efflux of K+ in serum deprived quiescent cells. The addition of partially purified fibroblast growth factor (FGF) to G0/G1 phase 3T3 fibroblasts induced a transient net influx of K+, carried out by the bumetanide-sensitive transport system for 2-6 minutes. The stimulation of the bumetanide-sensitive K+ influx by FGF was followed by stimulation of the ouabain-sensitive K+ influx. In addition, both the bumetanide-sensitive and the ouabain-sensitive K+ influxes were found to be similarly stimulated when the G0/G1 3T3 cells were treated with insulin. These results suggest that growth factors such as FGF and insulin induce a change in the action of the bumetanide-sensitive transporter from performing net K+ efflux along its concentration gradient to an uphill transport pumping of K+ into the cell. We propose, therefore, that the bumetanide-sensitive transporter contributes to the increase in the intracellular K+ (and probable Na+) stimulated by growth factors such as FGF and insulin in early G1 phase of the cell cycle.

Animals↗
PubMed1985

Control of K+ influx in 3T3 cells transformed by a conditional mutant of Rous sarcoma virus.

Mouse 3T3 cells transformed by a conditional mutant of Rous sarcoma virus (LA90) can assume either a normal or a transformed phenotype, depending on the temperature of cultivation. These cells (LA90) were arrested at the G0/G1 phase of the cell cycle by starvation for serum growth factors at the nonpermissive temperature (39 degrees C). Release from the G0/G1 phase by serum growth factors resulted in a rapid stimulation of Rb+ influx. To investigate whether the stimulation of Rb+ influx is obligatory for cell proliferation, the cultures were released from the G0/G1 phase by a temperature decrease in the absence of serum. A temperature decrease from 39 to 32 degrees C activated the viral pp60src gene mitogenic activity. Under these conditions, no rapid stimulation of Rb+ influx was observed. These results suggest that the rapid stimulation of Rb+ influx induced by serum growth factors is not an essential signal for cell release from the G0/G1 phase. However, a delayed increase in Rb+ influx concomitant with an increase in the cell content of K+ was observed in the cultures released from the G0/G1 phase by temperature decrease in the absence of serum growth factors. We found that the LA90 cells incubated at the permissive temperature (32 degrees C) secreted a mitogenic activity into the medium. Moreover, the conditioned medium from cultures incubated at 32 degrees C, but not at 39 degrees C, stimulate Rb+ influx in G0/G1 cells. These results indicate that Rous sarcoma virus pp60src induces a slow autocrine secretion of a mitogenic activity. This mitogenic activity slowly modulates the K+ content. Therefore, the slow elevation in cellular content of K+ is proposed to be an obligatory event for proliferation in normal and transformed cells.

Animals↗
PubMed1985

Management of obstructive carcinoma of the left colon. Comparative study of staged and primary resection.

Of 82 patients who had obstructing cancer of the left colon, 22% had incurable disease and 36.5% had advanced cancer at presentation. All methods of treatment carried a high morbidity and mortality. The mean survival rate with palliative operations was 8.7 months. Twenty-four poor-risk patients treated with staged operations had a 25% operative mortality and a 20.8% five-year survival rate. Forty primary resections, with or without anastomosis, were followed by a 27.5% operative mortality and by more than a twofold five-year survival rate (47.5%) compared with that of staged resection. These results suggest that delay of cure may reduce the late survival rate and justify primary resection as the operation of choice in selected good-risk patients.

Colectomy↗
PubMed1985

Estimation of scatterer volume density near a concentration gradient.

A general formulation of the echo received from a random scatterer ensemble illuminated by a short electromagnetic or sonic signal is developed. It is shown theoretically and confirmed experimentally with ultrasound, that a gradient in scatterer density will return an echo which is partially spatially coherent (i.e. specular). The surface of a random ensemble of uniform scatterers is shown to produce an echo from whose degree of coherence, the scatterer density and cross section can be calculated.

Animals↗
PubMed1980

Biwinged excision for closure of rounded defect.

A new technique for closure of rounded defects is described. The biwinged procedure consists of excising two equal triangles on either side of the defect, one above and one below the dissecting line. Closure is in the form of a step. It can be made to parallel in part a wrinkle or contour line, such as a nasolabial fold, a temporal region above and beside the eyebrow, an area over the lower border of the mandible, or on the dorsum of the hand. A mathematical comparison of the amount of healthy tissue in the biwinged excision and in six other procedures is presented.

Basal Cell Carcinoma↗
PubMed1978

Effect of an egg-rich diet on plasma lipids and proteins in severely burned patients.

Eight severely burned young patients were maintained on an oral hyperalimentation regimen of about 7,000 calories--including 314 proteins, 600 g carbohydrates and 336 g fats, containing greater than 8 g cholesterol--based mainly on a daily ingestion of 35 eggs. Serum cholesterol and protein, and plasma lipoprotein levels were measured during period of 30 days on the diet. The mean serum cholesterol level prior to the egg-rich diet was low [108 +/- 42 (SD) mg/dl] and it remained within the normal range during the study. The initial mean serum total protein level of 4.1 +/- 0.5 (SD) rose to 6.5 +/- 0.7 g/dl by the 19th day and stayed high throughout the remainder of the study. Plasma lipoprotein levels, assessed by nephelometry and reported as concentrations of large, medium and small particles, were not increased. It is assumed that the high demand for energy during recovery from burns prevented abnormal rises in plasma lipid levels on fat-rich diet.

Adult↗
PubMed1976

Some physical properties of the Haifa occlusive dressing for burns.

In order to evaluate some of the physical properties of the Haifa Occlusive Dressing, which is in use in our Department, temperature, moisture and the transfer of gases were measured. The Haifa Occlusive Dressing does not significantly raise the temperature of the covered burn, nor does it hinder the diffusion of gases, even when wet. Measurements taken from a patient suffering from a deep second degree burn showed that the amount of secretion over a 9-h period was 270 cm3 and the rate of secretion/unit area was 0.0125 cm/h.

Absorption↗