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Biomedical subjects

G H Thomas

Publications and source records attributed to G H Thomas.

At least 145 records · Page 8Linked to original sources

Hyperpipecolic acidemia associated with hepatomegaly, mental retardation, optic nerve dysplasia and progressive neurological disease.

A male infant with hyperpipecolic acidemia is described. To our knowledge this is only the second report of this disorder. As with the previous case, our patient's course was characterized by persistent hepatomegaly, severe mental retardation, progressive loss of developmental milestones and diminished visual acuity associated with nystagmus, abnormal discs and retinal changes. Death occurred at 2 years of age, following a progressive loss of neurological function. Pipecolic acid was repeatedly present in the serum at a concentrattion of 4-5 mg %. Trace amounts of this compound were also detected in the urine. In addition, an adaption of the method of Piez et al. (1956) for the direct quantitation of pipecolic acid in serum was evaluated and found to be very useful for the biochemical diagnosis of this disorder.

Amino Acid Metabolism, Inborn Errors↗

Mucolipidosis III (pseudo-Hurler polydystrophy): Clinical and laboratory studies in a series of 12 patients.

Mucolipidosis III (pseudo-Hurler polydystrophy) is an autosomal recessively inherited Hurler-like disorder without mucopolysacchariduria. Previous reports have noted a constellation of laboratory features similar to that described for mucolipidosis II (I-cell disease). Studies were carried out on a series of 15 patients. Twelve were found to have changes in serum and cultured fibroblasts which consisted of marked elevations of several acid hydrolases in serum with low levels of the same enzymes in cultured cells, a marked increase in dense cytoplasmic inclusions and abnormal radioactive sulfate kinetics. The clinical features of these 12 patients comprise a phenotypic entity. Despite clinical similarity, the 3 remaining patients were not felt to represent mucolipidosis III. The basic defect in mucolipidosis III remains unknown, but is suggested that the defect is similar to that of mucolipidosis II, from which it must be distinguished clinically.

Adolescent↗

Oestradiol uptake and retention, and high-affinity binding sites in cultured rabbit uterus.

Oestradiol uptake and turnover was examined in rabbit uterus maintained in organ culture for up to 3 days. Serum decreased the uptake of [(3)H]oestradiol, whereas insulin had no significant effect. During the first 24h of culture unoccupied high-affinity receptors for oestradiol were markedly depleted in the cytosol. Nuclear binding sites remained high during the first day of culture, and were still present after 3 days. The stability of nuclear-bound oestradiol was confirmed by examining the turnover of radioactivity during culture of uteri of rabbits injected with [(3)H]oestradiol 6h before death. Over half of the radioactivity was retained for as long as 3 days in tissue cultured in the absence of oestrogen. In tissue cultured for 24h with unlabelled oestrogen, there was a progressive increase in the displacement of [(3)H]oestradiol as the concentration of unlabelled hormone in the medium was increased from 0.1 to 5nm. Higher concentrations of oestradiol had little additional effect. The oestradiol involved in this displacement reaction was associated with macromolecules, characterized by Sephadex G-25 chromatography and sucrose-density-gradient ultracentrifugation of the 0.4m-KCl extract of the nuclear pellet.

Animals↗

Morphological changes of benign prostatic hyperplasia in culture.

A technique is described for the culture of slices of benign prostatic hyperplasia (BPH) for periods of a week in organ culture. Under these conditions tissue repair took place, resulting in a covering layer of transitional epithelium which formed around the explant and spread out laterally as a monolayer. Autoradiography and studies with [(3)H]thymidine uptake suggested that the repair activity, which reached a peak at Day 3 in culture, was the centre of biochemical activity, overshadowing that of the rest of the explant. Necrosis of the explant base tended to develop abruptly during the first day of culture but thereafter remained stable. The epithelium was well preserved morphologically, but explant acid phosphatase activity fell progressively.No morphological response to testosterone (10(-5) mol/l) or stilboestrol diphosphate (10(-5) mol/l) was seen.Attention is drawn to a possible source of misinterpretation of results offered by the uptake of [(3)H]thymidine into DNA in organ culture.

Acid Phosphatase↗