Cell population density and phenotypic expression of tissue culture fibroblasts from heterozygotes of Lesch-Nyhan's disease (inosinate pyrophosphorylase deficiency)

Radioautographic examination of skin fibroblasts grown in tissue culture from normal donors revealed heavy labeling of almost all cells following incubation with tritiated hypoxanthine. Cells from patients with Lesch-Nyhan's disease, lacking inosinate pyrophosphorylase, had only 10 grains or less per cell. When normal and abnormal cells were mixed prior to culture, there was a progressive increase, with culture time, in the percentage of heavily labeled cells so that by 96 hr, when the cells were confluent, over 95% of the cells were heavily labeled. Reduction of cell density by subculture produced a reversion to original values. Cultures from three obligatory heterozygotes revealed the expected mixed population of cells. This appears to be a practical approach to the identification of the heterozygote.Aided by USPHS CA08748 and GM15508, and the Health Research Council of the City of New York.     

Computer-assisted Follow-up Register for the North-East of Scotland

An automated follow-up register for the detection of iatrogenic thyroid disease has been established as a joint venture between the general practitioners in the north-east of Scotland and the thyroid clinic of Aberdeen General Hospitals.The data-processing operations in the system are handled by an International Computers Limited 4/50 computer. Patients are followed up at predetermined intervals and the system has been designed to process, screen, and store clinical and biochemical follow-up data and report results to the patients, general practitioners, and the hospital records department.     

Amino acid sequences around the cystine residues in horse growth hormone

The cystine-containing peptides of horse growth hormone were isolated and their amino acid sequences determined. Four unique half-cystine residues occur in two peptides, one containing 11 and the other, at the C-terminus of the protein, 15 amino acids. These sequences are compared with published data on growth hormones from other species.     

Purine Ribonucleosidase g from Aspergillus foetidus

Nucleosidase g was prepared by growing Aspergillus foetidus on bran, and was purified by passage through a diethylaminoethyl-Sephadex column. The enzyme acted on the purine ribosides (except xanthosine) and on their 5'-phosphates. Action on the latter was a good means for preparing ribose-5-phosphate.     

Digestion by the larva of the pruinose scarab, Sericesthis geminata

An in vitro study of digestion by the subterranean larva of S. geminata revealed the presence of enzymes able to digest starch, trehalose, salicin, cellobiose, melibiose, maltose, sucrose, casein, and several forms of cellulose. The midgut is the major source of all enzymes except invertase and CMC-cellulase, for which hindgut preparations are more active. The pH values of the gut contents are: foregut 6.9, midgut 9.0 and hindgut 7.5. The midgut fluid is pumped forward into the foregut, and the carbohydrases in it are generally more active at the pH of the foregut than at the pH of the midgut. It is possible, therefore, that the foregut, which is itself insignificant as a source of enzymes, is the site of considerable carbohydrate digestion. The proteinase is inhibited 28% by trypsin inhibitors.

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Zusammenfassung Eine in vitro-Untersuchung über die Verdauungsvorgänge in den unterirdisch lebenden Larven von S. geminata wies Enzyme nach, die Stärke, Trehalose, Salicin, Cellobiose, Melibiose, Maltose, Rohrzucker, Kasein und mehrere Celluloseformen abbauen können. Versuche mit Vorder-, Mittel- und Enddarmextrakten zeigten, daß der Abbau von Rohrzucker und CMC-Cellulose in Ansätzen mit Enddarmpräparaten prozentual am höchsten war. Maximale Verdauung aller anderen geprüften Substrate erfolgte dagegen mit Mitteldarmpräparaten.Die pH-Werte betrugen im Vorderdarm 6,9, im Mitteldarm 9,0 und im Enddarm 7,5. Im Mittel- und Enddarm lagen die jewciligen optimalen pH-Werte für Maltose bei 6,5–7,0 und 7,5, für Melibiose bei 6,0–7,0 und 7,0–7,5, für Cellobiose bei 6,0–7,0 und 4,5, für Rohrzucker bei 7,0 und 6,0, für CMC bei 5,2 und 5,6.Die Verdauung unlöslicher Celluloseformen war durchweg gering, die der CMC dagegen beträchtlich.Die Mitteldarmflüssigkeit wird nach vorn in den Vorderdarm gepumpt. Die darin enthaltenen Carbohydrasen sind beim pH-Wert des Vorderdarmes meistens wirksamer als in dem des Mitteldarmes. Es ist deshalb möglich, daß im Vorderdarm, welcher selbst wahrscheinlich keine Enzyme produziert, doch eine beträchtliche Kohlenhydratverdauung stattfindet.Die Wirksamkeit der Proteinase wird durch bekannte Tryptin-Hemmstoffe um 28% reduziert.

     

Failure of bacterial endotoxin to produce the generalized Shwartzman reaction in the Syrian hamster

The ability of bacterial endotoxin to produce the generalized Shwartzman reaction (GSR) in pregnant and nonpregnant hamsters was investigated. Endotoxins prepared from Escherichia coli O127:B8, Salmonella enteritidis, and S. typhosa 0-901 did not produce the GSR in nonpregnant hamsters. Injection of lead acetate did not make the hamsters susceptible to the GSR producing effects of endotoxin. Endotoxin administered to hamsters on either or both the 14th and 15th day of the 16-day gestation period caused fetal death, but did not provoke the GSR. The immunization of hamsters with boiled suspensions of gram-negative bacteria isolated from hamster feces did not protect against the GSR produced in pregnant hamsters by the injection of the antimitotic drug colchicine late in the gestation period. It appeared that colchicine was acting to produce the GSR by a mechanism other than the release of endogenous endotoxin through the damaged intestinal wall. Ascitic fluid, amniotic fluid, and serum obtained from pregnant hamsters developing the GSR after the administration of colchicine did not provoke the GSR in other pregnant hamsters.     

Effects of prolonged incubation of isolated fat cells on their response to hormones stimulating lipolysis and glucose metabolism

1. The metabolism of isolated fat cells from parametrial adipose tissue of starved normal rats was studied during 8hr. incubation. 2. There was a three- to eight-fold increase in conversion of glucose into carbon dioxide, fatty acids and glycerol during the fourth to eighth hours of incubation in 4% albumin buffer over that seen during the first 4hr. of incubation. 3. The addition of growth hormone and dexamethasone to fat cells at the start of the incubation period accelerated lipolysis during the first 4hr. of incubation but no further effect was seen during the fourth to eighth hours of incubation. Addition of growth hormone and dexamethasone to fat cells that had been incubated for 4hr. did not accelerate lipolysis during the next 4hr. whether fat cells were incubated with or without glucose. 4. Fat cells incubated for prolonged periods also displayed a reduced sensitivity to the lipolytic action of adrenocorticotrophic hormone. 5. During prolonged incubation there was no damage to the cells as judged by the retention of two soluble cytoplasmic enzymes, lactate dehydrogenase and malate dehydrogenase, within the cells.