Partial tetrasomy 9(9pter to 9q2101) due to an extra iso-dicentric chromosome.

A 3-year-old boy with partial No. 9 tetrasomy is described. The patient showed markedly retarded physical and mental development as well as multiple congenital anomalies. Routine chromosome analysis revealed an extra C-group chromosome. It had a pronounced secondary constriction at the proximal part of its long arm. Based on studies by a variety of banding techniques, the extra chromosome was identified to be an iso-dicentric No. 9 chromosome with inactivation of one of the two centromeres, the karyotype being 47,XY, + DIC (9)(Q2101). The value of BrdUrd treatment was emphasized in the detection of a very small piece of euchromatin within a long stretch of constitutive heterochromatin.     

Vitamin A receptors. II. Characteristics of retinol binding in chick retina and pigment epithelium

Gel filtration studies demonstrate that retinol receptors of chick retinal and pigment epithelial cytosols are (1) of very similar nature (2) of small molecular size (about 18000 daltons) and are different in character from serum proteins. Citral inhibits the binding of [3H]retinol to the retinal 2 S receptor. Retinol acetate competes with retinol for binding to 2 S receptor in both retina and pigment epithelium whereas retinol palmitate is an effective competitor only in the pigment epithelium. Dithiothreitol maximizes 2 S binding in retina and pigment epithelial cytosol; its absence does not lead to receptor aggregation however. A limited number of high affinity binding sites (2 S receptor) appear to be present in retina and pigment epithelium. A 5 S binding species is also present in pigment epithelium; it is similar in character to [3H]retinol binding in serum and may arise from serum contamination of the pigment epithelial preparation. Binding affinity in retina is high with possibly two classes of retinol binding sites present of KD about 1 - 10(-9) and 4 - 10(-8).     

Isolation and identification of 25-hydroxy-24-oxocholecalciferol: A metabolite of 25-hydroxycholecalciferol

A metabolite of 25-hydroxycholecalciferol has been isolated in pure form from chicken kidney homogenates. It has been identified as 25-hydroxy-24-oxocholecalciferol by means of ultraviolet absorption spectrophotometry, mass spectrometry, infrared spectrometry, nuclear magnetic resonance spectrometry, and specific chemical reactions.     

Human cell membrane components bound to beta2-microglobulin in T cell-type cell lines.

Cell membrane components bound to beta2-microglobulin were isolated from Renex 30 (a nonionic detergent)-solubilized membrane materials of two human T cell-type cell lines, MOLT-4 and CCRF-CEM, by gel filtration and lectin affinity chromatography. The isolation was carried out by following the beta2-microglobulin activity by radioimmune inhibition assay. The T cell membrane components bound to beta2-microblogulin had a uniform molecular size of about 200,000 daltons and most of them showed an affinity to lentil lectin. The isolated membrane components were radioiodinated and examined for identity to HLA antigens by sequential precipitation with rabbit anti-HLA antiserum (specific to HLA large components) and with rabbit anti-beta2-microblogulin antiserum. In addition to HLA antigens, the beta2-microglobulin-bound components obtained from the MOLT-4 cells were found to contain certain membrane components that are the same in molecular size as the HLA large components but that are different antigenically from the HLA large components. On the other hand, the beta2-microglobulin-bound membrane components obtained from the CCRF-CEM cells were all HLA antigens. No other membrane components were involved in the binding.     

Stimulative effect of prostaglandins on production of hexosamine-containing substances by cultured fibroblasts (2) early effect of various prostaglandins at various doses

Early effects of various prostaglandins on the production of hexosamine-containing substances by cultured fibroblasts, which were derived from a rat carrageenin granuloma, were studied. At the stationary phase, the cells were exposed for 6 h to one of the prostaglandin A₁ (PGA₁), A₂, B₁, B₂, D₂, F_1α, F_2α, E₁, E₂ or arachidonic acid in various concentrations ranging from 0.01 to 10 μg/ml for all the stimuli and from 10 pg to 10 μg/ml for PGF_2α. The activity of the cells in incorporating ³H-glucosamine into hexosamine-containing substances (acidic) glycosaminoglycans and glycoproteins) during this period was compared with that of control cells. All the stimuli tested showed more or less stimulative effect on the synthesis of hexosamine-containing substances at their specific concentrations. PGF_2α was found to be the most potent stimulant and its stimulative effect was found significant even at the low concentration of 100 pg/ml. PGD₂, F_1α and E₂ were the next potent stimuli. Their optimum dose were around 1 μg/ml but they still had significant stimulation at the concentration of 0.01 μg/ml. Effect of PGE₂ was rather mild. Stimulation by PGA₁, A₂, B₁ and B₂ or arachidonic acid was seen at high dose, and its seemed to be non-specific. The results suggested that these prostaglandins such as PGF_2α, D₂, F_1α and E₂ play some important role on regulating the production of intercellular ground substances.