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Biomedical subjects

G M Lewis

Publications and source records attributed to G M Lewis.

17 recordsLinked to original sources

BALB/cAn B cells and T cells have distinct susceptibilities to cytotoxic effects of snake venom.

Previous studies have analyzed abilities of snake venoms to preferentially kill certain animal cells. Some studies have examined selective cytotoxic effects of snake venoms on B and T lymphocytes, but few studies have determined abilities of snake venoms to interact with B and T cells at distinct stages of cellular development. Thus, this study has analyzed susceptibilities of immature and mature BALB/cAn splenic B cells and T cells to cytotoxic effects of crude venoms of snakes belonging to the families of Crotalidae, Elapidae, and Viperidae. Both mitogen-stimulated and unstimulated BALB/cAn Ig- splenic T cells are sensitive to cytotoxic effects of snake venoms whereas mitogen-stimulated but not unstimulated Ig+ splenic B lymphocytes are sensitive to snake venoms. We also find that BALB/cAn myelomas but not B cell lymphomas are sensitive to cytotoxic effects of snake venoms. In addition, plaque forming cells making IgG1 subclass in BALB/cAn mitogen-stimulated spleens and in myelomas are preferentially killed by venom of pit viper Bothrops asper. Thus, the cytotoxic effects of crude snake venoms can distinguish BALB/cAn PFC making IgG1 subclass from other B and T cells.

Animals

The preferential effects of chloroquine on the IgM and IgG subclass responses to TI and TD antigens in BALB/cAn mice.

This study has determined the effects of chloroquine on the IgM and the IgG subclass responses of BALB/cAn mice to both thymus-independent (TI) and thymus-dependent (TD) antigens, and has found that in antigen-unprimed BALB/cAn mice chloroquine adversely affects antibody responses to both TI and TD antigens. However, in antigen-primed mice the immune responses to TD antigens were unaffected by chloroquine. The IgGl subclass response, but not necessarily other IgG subclass or IgM responses to TI and TD antigens, was adversely affected by chloroquine in unprimed mice only. Thus, in unprimed, but not in antigen-primed, BALB/cAn mice, chloroquine preferentially decreased the IgGl subclass responses to both TI and TD antigens.

Animals

Myofibroblasts in cotton-induced granulation tissue and the bovine adrenal capsule: morphological aspects.

Ultrastructural studies of one week old cotton-induced granulation tissue revealed the presence of polymorphonuclear neutrophils (PMN), macrophages and mast cells, whilst the granulation tissue from two week old cotton implants contained fibroblasts, myofibroblasts and abundant collagen fibres. Similarly, the bovine adrenal capsule contained both fibroblasts and myofibroblasts. It is proposed that the bovine adrenal capsule and two week cotton-induced granulation tissue could be utilized as in-vitro models to study the mechanism(s) involved in myofibroblast contraction.

Adrenal Glands

Prolonged expiratory apnoea (cyanotic 'breath-holding') in association with a medullary tumour.

From the age of four months to his sudden, unexpected death at 2 years 11 months, a child had severe cyanotic episodes attributed to cyanotic 'breath-holding' (prolonged expiratory apnoea). At postmortem he was found to have a previously undiagnosed gangliocytoma of the medulla, which had invaded the floor of the fourth ventricle and variably affected the 7th to 12th cranial-nerve nuclei.

Apnea

Interstitial deletion of chromosome 7 detected in three unrelated patients.

Chromosome studies were carried out on three patients for the following reasons: (1) growth retardation and mental subnormality in a boy; (2) marked developmental delay in a female infant; (3) routine check on a man whose wife had a stillborn with congenital anomalies. An interstitial deletion at 7q11::7q21 was observed in all three cases.

Abnormalities, Multiple

Droperidol.

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Benperidol

Hyperventilation.

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Arrhythmias, Cardiac

A case of monthly unipolar psychotic depression with suicide attempt by self-burning: selective response to bupropion treatment.

A second case of monthly, unipolar, psychotic depression is presented, involving a 26-year-old woman whose illness had a postpartum onset, recurred premenstrually for 33 consecutive months, and involved a suicide attempt by self-burning. Whereas various antidepressant, antipsychotic, and hormonal treatments were ineffective, bupropion (together with low-dose trifluoperazine) induced an immediate and complete remission that was maintained at a 16-month evaluation.

Adult