Biomedical subjects
Publications and source records attributed to I Laing.
Bromocriptine was administered to 2 subjects with gastrin-secreting tumors of the pancreas. The absorption of the drug was confirmed by a rise in growth hormone levels but no change in the elevated serum gastrin levels were observed. Bromocriptine does not appear to affect gastrin hypersecretion in the way that it influences the hypersecretion of pituitary hormones.
A radioimmunoassay for alpha1-fetoprotein in human maternal serum at 15-20 weeks' gestation using polyethylene glycol to separate bound and free antigen is described. A number of variables has been investigated to define optimal conditions for use at this gestation. The method gives results which agree with those from a double-antibody technique. It has good precision in the critical concentration range, and recoveries are satisfactory. The importance of including sufficient serum protein in the analytical system is stressed. There were systematic differences between three standard preparations of alpha1-fetoprotein, but three out of four antisera tested gave very similar results. The implications for screening for neural tube defects in early pregnancy are discussed.
Fourteen healthy women were screened for the following parameters throughout one complete menstrual cycle: levels of urinary oestrogens and pregnanediol; levels of plasma and urinary gonadotrophins; and pH, protein content and levels of peroxidase in the cervical mucus. It was found that concentrations of peroxidase in the cervical mucus were not a reliable index of ovulation.
Lead subacetate (0.5g) and 1000 units of vitamin D were given three times a week to four newly-weaned rhesus monkeys. In addition, two animals received only the vitamin D. The poisoned animals had an increase in the urinary excretion of delta-aminolevulinic acid, an elevated content of lead in the blood, and a fall in hemoglobin concentration. Between 6 and 18 weeks the animals suddenly developed ataxia, nystagmus, generalized weakness, and convulsions. At this time the animals were killed by perfusion of fixative and the brain prepared for light and electron microscopic studies. Definite morphological evidence of disease was confined to the central nervous system, except for one animal which showed the characteristic renal inclusions of lead poisoning. All animals showed PAS-positive globules associated with blood vessels and an exudative edema involving the white matter of the cerebral hemispheres and cerebellum. Ultra-structurally, this appeared as a granular precipitate within an expanded extracellular space. Alterations of nerve fibers were not seen in the white matter but axonal swelling was observed in the cerebral cortex. The perikaryon and neuropil appeared normal. The control animals showed no significant cerebral changes.
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Lead encephalopathy was induced in suckling rats by administering lead to the mother. The brains were studied by light and electron microscopy, and the results were compared with observations in the human disease as well as in cases of cerebral ischemia in children. In their severe forms, both human and experimental lead encephalopathies are characterized by exudative extracellular edema and perivascular PAS-positive globules. The latter consist of osmiophilic non-membrane-limited cytoplasmic inclusions located, in the rat exclusively and in the human predominantly, in perivascular astrocytes. Intervascular strands are also found in both forms of the disease. In the rat these consist of basement membrane surrounding endothelial cytoplasm. Chemically, experimental lead encephalopathy with morphologically demonstrable edema is associated with an increase in brain water, sodium and serum albumin. Relative to the serum concentration, the increase in water is disproportionately greater than the sodium or albumin. There were no demonstrable changes in chloride or potassium.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.