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Biomedical subjects

R Chazan

Publications and source records attributed to R Chazan.

At least 73 records · Page 4Linked to original sources
PubMed1982

The effect of triamcinolone acetonide on the phagocytosis by human polymorphonuclear leukocytes.

Using 3 H-thymidine-labeled bacteria, we investigated the phagocytosis by human polymorphonuclear leukocytes (PMN). PMN were isolated from 50 asthmatic and bronchitic patients treated with triamcinolone acetonide (TA). In general, the dose of TA was limited to 80 mg with an interval of 6 weeks or longer between AT injections. The phagocytosis of the Staphylococcus aureus Cowen-3 by the isolated PMN was inhibited. The strongest suppression of phagocytosis was observed on the 3rd day; after 14 days the phagocytic activity returned to normal.

Adult↗
PubMed1975

Pathways in thymus- and bone marrow-derived lymphatic leukemia in mice.

The radiation- and radiation leukemia virus-induced leukemias in C57BL/6 strain mice were found to be of the thymus-derived (T) lymphocyte origin. Experimental evidence indicated that the interaction of the radiation leukemia virus with thymus-derived lymphoid cells and specifically with the thymus subpopulation bearing high levels of H-2 alloantigens were prerequisites for the development of high leukemia incidence in these test systems. In radiation leukemogenesis in C57BL/6 mice it was shown that within several days following the radiation treatment a "released" leukemogenic agent was found in the irradiated bone marrow; whereas, several days following chemical carcinogen leukemogenesis in SJL/J mice, established preleukemic or leukemic cells could be detected in the bone marrow. The analysis concerned with the lymphoid origin of chemical carcinogen-induced lymphatic leukemias in SJL/J mice indicated clearly that the carcinogen could affect different lymphoid populations. The majority of the chemical-induced leukemias were of the bone marrow-derived (B) lymphocyte origin, although some leukemias were of T lymphocyte origin, and some tumors could not be classified as either T or B leukemias, perhaps representing stem cells which do not carry the characteristic surface antigens for mature T and B cells.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1975

Social integration and the therapeutic community.

The therapeutic community should be defined as an environment which is enabling but not directive. The staff need to become aware of their therapeutic as well as anti-therapeutic potential. Conflict should be overt rather than covert. That society now sees the delinquent as 'sick' is two-edged: Abdication of responsibility is encouraged, and the sick role rewarded. This paper shows how the therapeutic community is effective in encouraging the delinquent to take responsibility for himself and for others. It shows what features make the therapeutic community effective for neurotics for schizophrenics.

Humans↗
PubMedDate not supplied

CD4/CD8 lymphocytes in BALF during the efferent phase of lung delayed-type hypersensitivity reaction induced by single antigen inhalation.

BACKGROUND: The precise mechanisms involved in the pathogenesis of hypersensitivity pneumonitis (HP) have not been identified. HP is characterized by inflammatory lymphocytic alveolitis and a remarkable increase in T-lymphocytes detected in bronchoalveolar lavage fluid (BALF). It is suggested that both CD4+ and CD8+ T cells may contribute to the pathogenesis of HP. Experiments on animal models suggest that cell mediated immunity (CMI) is more important for the pathogenesis of HP than complex-mediated immunity, but the relationship between the subsets of BALF lymphocytes and humoral or cell-mediated allergic reactions is still not clear. The aim of our study was distinguish CD4+ and CD8+ T cells in BALF lymphocytes during a delayed-type hypersensitivity (DTH) reaction in the lung. MATERIAL AND METHODS: The experiment was performed on guinea pigs sensitized with BCG vaccine and subjected to a single inhalation of tubercle bacilli antigens (tuberculin). 24 hours after tuberculin provocation (at the time of maximum lymphocyte infiltration), bronchoalveolar lavage was performed on both sensitized and non-sensitized (control) animals. The total cell count was estimated, and a differential microscopical examination of BAL-fluid cells was performed, along with the phenotyping of BALF lymphocytes (by flow cytometry). RESULTS: In the BALF of the sensitized animals, as compared to the controls, there was a statistically significant increase in the percentage and absolute count of T-lymphocytes, CD4+ and CD8+. The CD4 / CD8 ratio in both groups did not differ significantly and was individually variable (2.94I0.72 SEM in the experimental group, vs 4.41I1.29 SEM in the control group). CONCLUSIONS: Both CD4+ and CD8+ lymphocytes (with some predominance of helper cells) participate in the efferent phase of the delayed type hypersensitivity reaction in the lung induced by antigen inhalation.

Animals↗
PubMedDate not supplied

[Electrocardiographic changes in patients with airway obstruction].

In severe bronchial asthma reversible electrocardiographic abnormalities are not rare. It is usually sinus tachycardia, right axis deviation, atrial enlargement and right bundle branch block. Transient ST-segment depression or elevation in inferior leads in severe acute asthma has been observed since long. Adrenergic stimulation, hyperventilation, hyperinflation and primary or secondary coronary insufficiency were as a causes. Severity of ECG signs correlated with the degree of airway obstruction. Our study was aimed at investigation of electrocardiographic abnormalities in chronic pulmonary obstructive disease and asthma and to assess the relationship of the extent of airway obstruction to the frequency of ECG changes. Correlation was found of ECG manifestation of sinus tachycardia, right ventricle hypertrophy. ventricular premature complex, right bundle branch block with the degree of airway obstruction.

Adolescent↗