Biochemical and cytogenetic studies on the Nucleolus Organizing Regions (NOR) of Man

Summary The hybridization kinetics of DNA with labeled (18s+28s)rRNA from HeLa cells was determined in patients with trisomy 21, healthy probands with normal karyotype and in carriers of a t(DqGq) centric fusion. The results are in, accordance with the saturation values obtained earlier for these probands:Three patients with trisomy 21 showed an increased saturation level. In 2 of these patients the excess of rDNA exceeded the expected value considerably.Three of the investigated translocation carriers t(14q21q) showed significantly reduced saturation values, while results of a fourth proband with a dicentric chromosome t(15q21q) were found to be within the range of normal probands.The heterogeneous results were correlated with the cytogenetic characteristics of the acrocentric chromosomes. It is expected that these differences could be explained on the basis of family analysis.

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Zusammenfassung Hybridisierungskinetiken der DNA mit markierter (18s+28s)rRNA aus HeLa-Zellen wurden ermittelt bei Patienten mit Trisomie 21, gesunden Probanden mit normalem Karyotyp und Trägern einer zentrischen Fusion t(DqGq). Die Ergebnisse bestätigen die bereits früher ermittelten Sättigungswerte von Hybridisierungen bei diesen Probanden:3 Patienten mit Trisomie 21 zeigten erhöhte Sättigungsniveaus. Bei 2 dieser Patienten übersteigt der Überschuß an rDNA den Erwartungswert erheblich.3 der untersuchten Translokationsträger t(14q21q) hatten signifikant erniedrigte Sättigungswerte, während die vierte Probandin mit dem dizentrischen Chromosom t(15q21q) im Normbereich lag.Die unterschiedlichen Befunde werden mit den cytogenetischen Eigenschaften der akrozentrischen Chromosomen in Zusammenhang gebracht. Es wird erwartet, daß diese Unterschiede sich durch Familienuntersuchungen aufklären lassen.

     

Intestinal Coccidiosis in a Patient with Alpha-chain Disease

During an ultrastructural study of small-intestinal mucosa from a patient suffering from alpha-chain disease organisms were identified within the epithelial cytoplasm which showed the fine structural features of the coccidian group. Though coccidiosis is well recognized as causing a diarrhoeal and often lethal illness in animals it has been neglected as a cause of disease in man. Thus this finding may be significant and warrants further investigation into its possible role in the pathogenesis of alpha-chain disease.     

Tissue glycogen concentrations in hypophysectomized pig fetuses following infusion with cortisol

The role of cortisol as a factor controlling the deposition of glycogen in the pig fetus was examined by infusing either a low dose (1 mg/day) or a high dose (3 mg/day) of cortisol into chronically-catheterized hypophysectomized fetal pigs for five days beginning on day 100-104 of gestation. After infusion, liver glycogen was significantly higher (P less than 0.05) and lung glycogen significantly lower (P less than 0.05) than in uninfused hypophysectomized litter mates although concentrations were significantly different from intact litter mates (P less than 0.05). Although skeletal and cardiac muscle content increased after infusion this difference was not significant. Changes in tissue glycogen content were similar for both the low and high rates of infusion. These observations indicate that exogenous cortisol alone is able to stimulate liver glycogen deposition and reverse the effect of hypophysectomy. Although other factors may be necessary for maximal response this suggests that cortisol is an important stimulant for liver glycogen deposition in the fetal pig. The effect of cortisol on muscle glycogen was equivocal suggesting that other hormones may play a more important role in this tissue.