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Biomedical subjects

Y Cohen

Publications and source records attributed to Y Cohen.

At least 343 records · Page 19Linked to original sources
PubMed1983

Effect of three anorectic drugs on central catecholamine levels and synthesis in the Zucker rat.

1. Genetically obese Zucker rats and their lean littermates were treated during 5 days with fenfluramine, mazindol or amphetamine. Norepinephrine and dopamine levels were assayed in the hypothalamus, striatum, medulla-oblongata pons and remainder of the brain, and the amine synthesis was estimated, when possible. 2. Fenfluramine acted especially on norepinephrine in the obese rat hypothalamus. 3. Mazindol was active on norepinephrine and dopamine levels only in obese animals. 4. Amphetamine acted on norepinephrine levels only in obese rats and on dopamine levels in both obese and lean rats.

Animals↗
PubMed1983

Brain catecholamine metabolism changes and hypothermia in intoxication by anticholinesterase agents.

Sublethal doses of physostigmine, paraoxon and soman induce a short-lasting fall in rat core temperature potentiated by alpha-methyl-para-tyrosine (alpha-MT) (early effects). When the own hypothermic effect of the anticholinesterase agent has disappeared (late effects), alpha-MT induces a new decrease in temperature. Parallel biochemical studies of catecholamine levels and turnover were performed in several brain areas. The norepinephrine (NE) turnover is generally increased particularly in the hypothalamus, suggesting that NE hypothalamic changes might be linked to a latent perturbation of thermoregulatory mechanisms. Furthermore, it was shown that soman acts differently from the other drugs by inducing quite important changes in both NE and dopamine levels.

Animals↗
PubMed1983

Multidrug chemotherapy using bleomycin, methotrexate, and cisplatin alone or combined with radiotherapy in advanced head and neck cancer.

Twenty-two patients with advanced cancer of the head and neck where treated with a combination of bleomycin, methotrexate, and cisplatin. In ten previously untreated patients, a complete response (CR) rate of 20%, a partial response rate of 50%, and a no change rate of 30% were observed. With the addition of radiotherapy, the local CR rate in this group of patients increased to 60%. In 12 patients with recurrent disease after surgery and/or radiotherapy, the CR rate was 25%, the partial response rate was 16.7%, and the no change rate was 58.3%. Toxic effects were acceptable, with no fatalities. These short-term results encourage accrual of more patients in the study and further follow-up to determine whether the cure rate can be increased by using cisplatin and radiotherapy in patients with advanced previously untreated head and neck cancer. More energetic treatment should be investigated in patients having disease recurrence after radiotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1983

Mechanism of the hypotensive action of practolol in the anesthetized rat.

Cardiovascular effects of acute administration of practolol were studied in groups of normotensive and spontaneously hypertensive rats. In some of these animals a strong and long-lasting hypotension was shown, resulting from a decrease in the total peripheral resistance. This hypotension was impaired by preventive propranolol administration, and did not result from a direct vascular effect. Moreover, it was previously reported that practolol induced a strong and long-lasting hypotension in all normotensive and hypertensive rats after blood-brain barrier disruption. From these experiments it is suggested that the blood pressure decrease observed in some groups of Okamoto rats may be due to a practolol action on central beta-receptors. The intensity of hypotension depends on the molecule penetration in the central nervous system, and seems to be related to blood-brain barrier lesions induced by genetic hypertension.

Animals↗
PubMed1983

Time course relation between neurotoxic effects of kainic acid on behaviour and brain GABA-levels. Protection by gamma-vinyl GABA.

Administration of kainic acid (KA, 11 mg/kg i.p.) to rats produced a syndrome of abnormal behaviour (hyperexcitability, stereotypies, convulsions, aphagia and aggressivity) as well as a reduction in brain GABA levels during the first days after treatment. Pretreatments of rats with gamma-vinyl GABA (900 mg/kg) elevated brain GABA levels and prevented the occurrence of convulsions and aphagia. The findings suggest that KA neurotoxicity is due in part to its disruptive effects on GABA neurotransmission.

Aminocaproates↗
PubMed1982

Neural systems control of spatial orienting.

A peripheral visual cue in an empty field (1) often summons head or eyes, or both, (2) improves efficiency at the cued position while attention is directed to it, even without overt movements, and (3) reduces processing efficiency at the cued position once attention is withdrawn. We have studied the time course and the effects of mid-brain and cortical damage on these components of orienting. The facilitation arises from shifts in covert attention. In cases of mid-brain degeneration due to progressive supranuclear palsy, saccadic movements were abolished, while covert orienting still occurs. However, covert orienting was found to be delayed in directions in which eye movements were most affected, suggesting a role for mid-brain pathways in covert orienting. Parietal lesions can cause massive loss in detection contralateral to the lesion. This is especially true when attention has been directed to the opposite side. These findings relate aspects of covert orienting of attention to neural control systems.

Attention↗
PubMed1982

Malignant lymphoma in first-degree blood relatives.

The statistical significance of familial lymphoma in first-degree blood relatives was evaluated for the series of all lymphoma cases referred to our department since 1968. Four pairs of immediate relatives with Hodgkin's disease (HD) were found among 183 patients diagnosed between 1960 and 1980. The expected number during that period was 0.45. Thus, close relatives of HD patients had about ninefold increased risk of the disease (P less than 0.005). Mixed-cellularity was the most common subtype in these familial cases (6/8 patients). There were three pairs of close relatives with non-Hodgkin's lymphoma (NHL) among 532 patients diagnosed during the same period, 1960-1980. The expected number was 3.86. These findings further indicate that HD may differ from NHL with regard to familial clustering.

Adolescent↗
PubMed1982

Treatment of advanced gastric carcinoma with 5-fluorouracil adriamycin, and mitomycin C (FAM).

Thirty-three evaluable patients with advanced gastric adenocarcinoma were treated with a combination of 5-fluorouracil, adriamycin, and mitomycin C (FAM). Two complete and five partial remissions (21% response rate) were observed. The overall median survival of all 33 patients was 5.9 months. Responding patients had significantly better survival than the non-responders (P less than 0.02). Analysis of the results according to sex, pretreatment performance status, and the histologic differentiation of the tumor failed to demonstrate that any of these factors influenced therapeutic results. The low response rate to FAM found in this study might be related to the fact that in the majority of the patients (85%) the primary gastric tumor had not been resected. The side-effects of this regimen were moderate. Taking into account the low response rate and the moderate myelotoxicity observed, a more intensive use of these three drugs in combination is suggested.

Adult↗
PubMed1982

Combined adjuvant therapy of radically operated colorectal cancer patients. (chemotherapy, radiotherapy, and MER-BCG).

Seventy-three patients with Dukes' B2 and C colorectal cancer were randomized to adjuvant therapy after radical surgery. One group was treated with chemotherapy either alone or in combination with radiotherapy (RC). The second group was treated by chemotherapy (with or without radiotherapy) plus MER/BCG (RCM). In patients with Dukes' C disease, the survival at 54 months and the disease-free interval up to 24 months were significantly better in the RCM than in the RC subgroup. There were no significant differences in the survival and disease-free interval between RC- and RCM-treated patients with Dukes' B2 disease. Entry of additional patients and further follow-up are needed before we can decide whether the combination of RCM increases the cure rate in Dukes' C cancer or merely delays recurrence and prolongs survival.

Adult↗
PubMed1982

Modification of rat brain 5-hydroxytryptamine metabolism by sublethal doses of organophosphate agents.

The early and late effects of sublethal doses of two organophosphate agents (paraoxon and soman) on 5-hydroxytryptamine (5-HT) metabolism were investigated in several rat brain areas. Parallel determinations of acetylcholinesterase (AcChE) inhibition were performed. An increase in 5-HT level was observed during the first phase of soman intoxication and a rise in 5-hydroxyindol acetic acid (5-HIAA) appeared in the early and late effects of both anticholinesterase agents with a predominant action in the striatum. These data suggested that paraoxon and soman induce a long-lasting increase in 5-HT turnover. This action cannot be related neither to the AcChE inhibition nor to the acetylcholine level.

Acetylcholinesterase↗
PubMed1982

Ultrastructure of square bacteria from a brine pool in Southern Sinai.

The square bacterium discovered by Walsby (Nature [London] 283:69-71, 1980) has been shown to possess the ultrastructural features of a typical halophile. The cell wall is comprised of regularly arranged subunits demonstrated by thin sectioning, shadowed replicas, and negative staining. Optical diffraction confirms the existence of both hexagonal and tetragonal arrangements of the cell wall subunits and also of different lattice constants and suggests a mixed population of bacteria.

Bacteria↗
PubMed1982

Bone marrow biopsy in solid cancer.

205 patients with solid cancer, underwent bone marrow biopsy using a Jamshidi needle, regular type. 32 (16%) biopsies were positive for bone marrow metastases. Results were correlated with those of skeletal radioisotope scans, X-ray films and the complaint of bone pain, alone or combined. 27 of 131 (17.5%) patients with positive X-ray film and 31 of 110 patients (28.1%) who complained of bone pain had a positive bone marrow biopsy. 17 of 46 (36.9%) patients with 3 positive parameters had a positive bone marrow biopsy as compared with none of 18 patients whose these 3 parameters were negative. Average values of Hb, WBC, serum alkaline phosphatase and calcium did not differ between patients with positive or negative bone marrow biopsy. 86 patients were diagnosed to have bone metastases and 35 more patients were diagnosed within a year following the biopsy. Of these 121 patients, 46 of 46 with positive scan, X-ray and pain were diagnosed to have bone metastases as compared to 27 of 30 patients with a positive scan with pain but negative X-ray film. Only 1 of 18 patients with negative parameters was diagnosed as having bone metastases within a year from biopsy. In our experience, it is of no value (unlike in malignant lymphoma and oat cell carcinoma of lung) to obtain a bone marrow biopsy for the detection of bone marrow micrometastases in asymptomatic cancer patients with negative skeletal radioisotope scan and negative bone X-ray films.

Biopsy, Needle↗