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Biomedical subjects

Y Cohen

Publications and source records attributed to Y Cohen.

At least 379 records · Page 21Linked to original sources
PubMed1979

Diurnal cycle of oxygen and sulfide microgradients and microbial photosynthesis in a cyanobacterial mat sediment.

The diurnal variation in the microgradients of O(2), H(2)S, and Eh were studied in the benthic cyanobacterial mats of a hypersaline desert lake (Solar Lake, Sinai). The results were related to light intensity, light penetration into the mat, temperature, pH, NH(4), photosynthetic activity, pigments, and the zonation of the microbial community. Extreme diurnal variation was found, with an O(2) peak of 0.5 mM at 1 to 2 mm of depth below the mat surface during day and a H(2)S peak of 2.5 mM at 2 to 3 mm of depth at night. At the O(2)-H(2)S interface, the two compounds coexisted over a depth interval of 0.2 to 1 mm and with a turnover time of a few minutes. The photic zone reached 2.5 mm into the mat in summer, and the main CO(2) light fixation took place at 1 to 2 mm of depth. During winter, light and photosynthesis were restricted to the uppermost 1 mm. The quantitative dynamics of O(2) and H(2)S were calculated from the chemical gradients and from the measured diffusion coefficients.

Journal Article↗
PubMed1979

Bone marrow biopsy in patients with malignant neoplasms other than lymphomas or leukemia.

104 patients with various cancer, excluding malignant lymphoma and leukemia, underwent bone marrow biopsy using a Jamshidi needle, regular type. In 100 patients an adequate pice of bone marrow was obtained. In 24 patients metastases were detected in the bone marrow. Metastases were found in 10 of 38 (26.3%) patients with breast cancer, in 5 of 17 (29.4%) patients with lung cancer, in 5 of 10 (50%) patients with cancer of the prostate, in 1 patient with rhabdomyosarcoma, 1 with chordoma and in 2 of 14 patients who underwent biopsy in search of unknown cancer. 71% of the patients with positive findings in the bone marrow had clinical signs of bone involvement, 80% had positive X-ray film and 78.9% had positive skeletal isotope survey. Hemogram, serum alkaline phosphatase, serum calcium level and sedimentation rate were of no value in predicting whether the marrow was involved or not. No complications were documented following biopsy. The use of the Jamshidi bone marrow biopsy needle for staging and early detection of metastases in a select group cancer patients is suggested.

Adolescent↗
PubMed1979

Vitiligo associated with BCG-methanol extraction residue in malignant melanoma. Report of a case.

A pronounced vitiliginous reaction developed at the sites of MER/BCG injections given as an adjuvant immunotherapy to a patient with malignant melanoma. To our knowledge, this is the third report on patients exhibiting vitiligo apparently induced by immunotherapy and the first in association with MER. This association may be a sign for an antimelanocytic effect and may offer a further confirmation for the autoimmune nature of vitiligo.

Adult↗
PubMed1979

Adjuvant therapy in colorectal cancer. (A randomized trial comparing radio-chemotherapy and radio-chemotherapy combined with the methanol extraction residue of BCG, MER).

Fifty-three patients with colorectal cancer Dukes' B2 and C were randomized after surgery. One group was treated by radio-and/or chemotherapy and the second by radio-and/or chemotherapy and MER. After 24 and 36 months a significant longer disease free interval, lower recurrence rate and better survival was found in the group treated by radio-chemo- and immunotherapy. Treatment was well tolerated and there were few local side effects from the MER injections. The long time efficacy of this adjuvant treatment whether it increases the cure rate or only delays recurrence does require longer follow-up.

BCG Vaccine↗
PubMed1978

Leiomyosarcoma of the rectum: report of three cases.

Three cases of leiomyosarcoma of the rectum are reported. The first patient underwent palliative surgery and died 18 months after diagnosis; local radiotherapy was not effective and chemotherapy failed as well. The second patient underwent radical surgical treatment but monetheless the tumor recurred and the patient died 37 months after diagnosis. The third patient underwent radical surgery for a tumor that was in an early stage, has been followed for several months without evidence of disease. Review of the literature indicates that leiomyosarcoma of the rectum is the most malignant sarcoma of the gastrointestinal tract, and has a 20 per cent five-year survival rate. Even radical surgical treatment yields disappointing results. Following localized operations, recurrences appear in most cases, and this treatment is not recommended. Should an effective chemotherapeutic combination be found, chemotherapy as an adjuvant to surgery will probably be indicated.

Aged↗
PubMed1978

Multiple lymphocyte transformation tests by phytohemagglutinin in healthy individuals: transient episodes of decreased lymphocyte blastogenesis.

146 serial determinations of spontaneous and phytohemagglutinin-induced lymphocyte transformation as measured by tritiated thymidine incorporation, were performed in 24 healthy individuals. 9 persons were studied intensively during a mean period of 40 days and the other 15 underwent random investigations during a period up to 10 months. Transient episodes of significant decreased lymphocyte transformation were revealed in 14 persons (58.4%) with regard to the spontaneous blastogenesis and in 11 subjects (45.8%) with regard to PHA-induced reactivity. The occurrence of the decreased values in PHA responsiveness was significantly higher in the intensively studied group compared to the randomly investigated one (p = 0.001). The probability of detecting one low PHA-related response in a normal subject was 11%. In only half of the cultures with low spontaneous blastogenic response did a simultaneous decrease in PHA-induced lymphocyte transformation occur. In addition to the currently used stimulation index, a new index termed the Blastogenic Cumulative Index is proposed. It is defined as the sum of the logarithms of the dpm values of the spontaneous and the PHA induced lymphocyte transformation. The CI is suggested to describe lymphocyte blastogenic function more accurately, and due to its simplicity warrents further study. Other indices for lymphocyte blastogenesis determination are discussed.

Cells, Cultured↗
PubMed1978

Hypotensive action of beta-blocking drugs injected into the cerebral ventricle of the rat.

Pindolol, propranolol, practolol, N-isopropyl-p-nitrophenyl-ethanolamine (INPEA), d and l-alprenolol were injected into the lateral cerebral ventricle of the anaesthetized rat. Except for INPEA, which has no action at the doses used, these various beta-blocking agents produce a dose-related fall in blood pressure. D-alprenolol and practolol seem to be the least active of the hypotensive agents. Our results show some relationship between the beta-blocking potency of the drugs studied and the hypotension induced when they were injected in the lateral ventricle.

Adrenergic beta-Antagonists↗