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Biomedical subjects

H Baker

Publications and source records attributed to H Baker.

At least 235 records · Page 13Linked to original sources
PubMed1981

Clinical and metabolic abnormalities in a boy with dietary deficiency of biotin.

Dietary deficiency of biotin was documented in an 11-year-old retarded boy as a consequence of a dietary prescription containing raw eggs. Clinical manifestations were alopecia totalis and an erythematous, exfoliative dermatosis. Metabolic characteristics included increased excretion of 3-methylcrotonylglycine, 3-hydroxyisovaleric acid, 3-hydroxypropionic acid, methylcitric acid, and lactic acid, as well as a propensity for the development of ketosis. The activities of propionyl coenzyme A carboxylase and 3-methylcrotonyl coenzyme A carboxylase in extracts of leukocytes were deficient. Treatment with biotin and the removal of raw eggs, which contain the biotin-binding protein, avidin, from the diet led to the reversal of all of the clinical and metabolic manifestations observed.

Alopecia↗
PubMed1980

Itch.

Explore the source record for details and available documents.

Anesthetics, Local↗
PubMed1980

Development of a scleroderma-like illness during therapy with L-5-hydroxytryptophan and carbidopa.

A scleroderma-like illness developed in a patient treated with L-5 hydroxytryptophan (L-5HTP) and carbidopa for intention myoclonus. The patient had high plasma kynurenine levels that remained high when the L-5HTP-carbidopa combination was discontinued, However, levels rose futher on drug rechallenge, suggesting that the drug unmasked an abnormality in one of the enzymes that catabolize kynurenine. Plasma kynurenine was also determined to be high in seven of 15 patients wth idiopathic scleroderma, but not in eight patients with intention myoclonus treated with L-5HTP and a decarboxylase inhibitor and in whom scleroderma did not develop or in 10 patients with Parkinson's disease treated wth L-dopa and carbidopa. Our data and studies in the literature suggest that two factors may be important in the pathogenesis of some scleroderma-like illness: high plasma serotonin and the abnormality associated with elevated kynurenine.

5-Hydroxytryptophan↗
PubMed1980

Genetic control of number of midbrain dopaminergic neurons in inbred strains of mice: relationship to size and neuronal density of the striatum.

The activity of tyrosine hydroxylase [TyrHase; tyrosine-3-monooxygenase; L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] is 20% less in whole midbrain of CBA/J mice than BALB/cJ mice and is paralleled by a comparable difference in the number of dopaminergic neurons in which the enzyme can be detected immunocytochemically. The strain-dependent difference in numbers of TyrHase-containing neurons and of TyrHase activity is not homogeneous in the midbrain but is restricted (along the rostral-caudal axis) to the medial one-third, where almost 2-fold variations are found. The volume of the striatum, a major projection field of midbrain dopamine neurons, is 20% smaller in CBA/J than in BALB/cJ mice; the difference is regional and is concentrated in the caudal half. Because the packing density of intrinsic neurons of the striatum is similar in both strains, CBA/J mice contain 20% fewer neurons than do BALB/cJ mice. The activities of TryHase and of choline acetyltransferase (ChoAcTase; acetyl-CoA:choline-O-acetyltransferase, EC 2.3.1.6) in the whole striatum of CBA/J mice are less than in BALB/cJ. The strain-dependent differences in midbrain TyrHase activity are due to variations in the number of dopamine neurons and directly correlate with differences in the number of striatal cholinergic neurons. There is genetic control of the number of neurons of a neurochemically specific class in the mammalian brain.

Animals↗
PubMed1980

Oral versus intramuscular vitamin supplementation for hypovitaminosis in the elderly.

Thiamin, folate, biotin, riboflavin, nicotinates, pantothenate, carotenes, and vitamins B6, B12, A, E and C were measured in the blood of 228 elderly ambulatory residents of a nursing home. Their mean age was 87 years (range, 60-102). None had undergone major surgical procedures; their diet was good, and each had received at least one multivitamin pill every day for 3 to 5 months before the study. A comparison group of 204 healthy volunteers, aged 20-50 was also studied. Of the 228 elderly subjects, 88 (39 percent) showed vitamin deficits despite oral vitamin supplementation. Single and multiple deficits of vitamin B6, nicotinate, vitamin B12, folate, and thiamin were found. Three months after a single intramuscular injection of multivitamins (with no other vitamin supplementation), these deficits were no longer detectable in the blood of 89-100 percent of the vitamin-deficient elderly. Intramuscular rather than oral vitamin supplementation is a more effective method for maintaining adequate blood levels of vitamins in the elderly; the intramuscualr route apparently promotes saturation of tissue stores with enough vitamins to meet the needs, and thus obviates problems of vitamin malabsorption possibly due to drug interference or small-bowel atrophy.

Administration, Oral↗
PubMed1979

Appearance of catecholamine-synthesizing enzymes during development of rat sympathetic nervous system: possible role of tissue environment.

We sought to determine, in rat embryo, when and at what site in their migration cells derived from the neural crest differentiate into sympathetic neuroblasts. This has been accomplished by immunocytochemical detection, within the cells, of the enzymes catalyzing catecholamine biosynthesis-tyrosine hydroxylase [TH; tyrosine 3-monooxygenase, L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] dopamine-beta-hydroxylase [DBH; 3,4-dihydroxyphenylethylamine,ascorbate:oxygen oxidoreductase (beta-hydroxylating), EC 1.14.17.1)]-and, as a marker of prospective adrenal medullary cells, the enzyme phenylethanolamine N-methyltransferase (PNMT; S-adenosyl-L-methionine:phenylethanolamine N-methyltransferase, EC 2.1.1.28). TH and DBH, not detected in the neural crest, appear almost simultaneously in cells of the thoracic sympathetic ganglia in 11-day-old embryos, and in abdominal and lumbar ganglia 1-2 days later, thereby exhibiting a characteristic rostral-caudal gradient of differentiation. Cells stained for TH and DBH are seen in the gut wall from day 11 to day 14, but not thereafter. Cells stained for TH and DBH appear in the adrenal anlage at day 15. However, PNMT is not detected in the adrenal until day 17 of development, and is present only in the sympathoblasts in contact with the adrenal cortex. Treatment of pregnant rats with dexamethasone failed to accelerate the appearance of PNMT in the embryo or to initiate its expression in cells of other sympathetic organs. We conclude that neural crest cells express a noradrenergic phenotype only after leaving the neural crest and that these cells are labile with respect to their neurotransmitter and are capable of transformation in response to environmental stimuli.

Adrenal Glands↗
PubMed1979

School phobic children at work.

Seventy-one school phobic children seen at a child guidance clinic were followed up after they had passed school leaving age. Their record in work and further education was compared with the length of time they were off school, whether or not they returned to school, and the occurrence of further psychiatric treatment after discharge from the clinic. It was found that whether or not the child returned to school and the length of time he was off school had no relationship to future performance at work or in further education. A significantly larger number of children receiving further psychiatric treatment after discharge from the clinic failed to reach their potential in work or further education. Adequate treatment of the underlying conditions appears to be more important than returning the child to school.

Absenteeism↗
PubMed1979

A vitamin profile of heroin addiction.

Circulating thiamine, riboflavin, nicotinates, folates, vitamin B12, B6, A, and carotenes of 149 heroin addicts aged 17-60 years were compared to 204 healthy subjects not using drugs or vitamins. Only 24 per cent of the addicts had no evidence of hypovitaminemia; 45 per cent and 37 per cent had vitamin B6 and folate deficit respectively, whereas deficits of thiamine, vitamin B12, riboflavin, and nicotinate were recorded for 13-19 per cent of the addict population; impaired liver function in addicts did not influence these results.

Adolescent↗