Morphological and biochemical effects of glucocorticoids in chick embryo hepatocytes during development.

The administration in ovo of hydrocortisone-21-phosphate caused, in chick embryo liver, a reduction of the number of hepatocytes which can be isolated from 1 mg dry weight of liver and a marked increase of their size. Moreover, the treatment diminished the incorporation of thymidine into acid-insoluble fraction in these cells whilst it augmented the content of protein, RNA, DNA and the level of thymidine kinase/cell. These effects were highest at 8-10 days, then declined with the age, disappearing after 18th day of incubation.

Colonization resistance of the human intestinal microflora: testing the hypothesis in normal volunteers.

Colonization resistance is the mechanism whereby the intestinal microflora protects itself against incursion by new and often harmful microorganisms. Some authors have claimed that colonization resistance is related to the integrity of the anaerobic flora, but this point has not been established in humans. In previous studies in our laboratory cefoxitin, piperacillin, cefoperazone or aztreonam were administered intravenously to healthy volunteers in order to study changes in the intestinal flora and acquisition of new strains.

Prepubertal endocrine follow-up in subjects with Wilms' tumor.

Twenty-three prepubertal subjects treated for Wilms' tumor (10 males and 13 females) were endocrinologically evaluated off therapy from 0.5 to 4.08 years.

Influence of hydrocortisone on chick embryo retina development.

Treatment of chick embryos in ovo with hydrocortisone-21-phosphate (a single dose of 150 micrograms) caused a marked reduction of retinal thymidine kinase activity 24 h later. The inhibitory effect was highest (65-70%) in 8-10-day-old embryos and declined with age, disappearing after day 15. It was accompanied by a reduction in thickness of the retinal layers.

Effect of broad-spectrum parenteral antibiotics on "colonization resistance" of intestinal microflora of humans.

Studies with animals have shown that the normal intestinal microflora protects against colonization by new strains ("colonization resistance") and that this protective effect may be related to the anaerobic component of the microflora. However, colonization resistance has not been shown in humans. We administered cefoxitin, piperacillin, cefoperazone, and aztreonam intravenously to healthy subjects for 9 days and monitored the acquisition of new isolates in the fecal flora.

Effect of broad-spectrum parenteral antibiotics on composition of intestinal microflora of humans.

We compared the effects of four beta-lactam drugs with widely differing antibacterial and pharmacological properties on the composition of the intestinal flora. Cefoxitin, piperacillin, cefoperazone, and aztreonam were given intravenously for 9 days to healthy volunteers. Cefoperazone reduced the numbers of aerobic and anaerobic bacteria to undetectable levels.

Isolation of Clostridium difficile from human jejunum: identification of a reservoir for disease?

The possibility that the small intestine may represent a reservoir for Clostridium difficile was studied, using segments of human jejunum collected at necropsy. Our results (three of 100 specimens positive for C difficile culture) support the hypothesis that C difficile can be found in human jejunum and that it adheres to the normal mucosa as a resident bacterium. These findings suggest that gastrointestinal disease caused by C difficile has an endogenous origin.

Report of a family with hereditary site-specific colon cancer.

A large family with a high prevalence of colorectal cancer, presenting the major features of hereditary site-specific colon cancer (i.e., autosomic dominant model of heredity, absence of associated adenomatous polyposis, prevalence of right-sided colonic lesions, and young age of the patients) is described.

Nucleoside phosphotransferase in animal tissues. Tissue distribution and kinetic properties.

Amphibian, avian and mammal tissues contain a nucleoside phosphotransferase clearly different from those previously described in vegetables and bacteria. Whatever the animal source, the enzyme showed many similar characteristics as far as substrate specificity, dependence upon Mg2+, instability at 37 degrees C, and the protecting effect of nucleotides were concerned. Moreover, when submitted to gel filtration, the enzyme behaved in all cases as a dissociable high molecular weight protein, whose degree of association was controlled by nucleotides.

[Evaluation of various methods of preserving samples for the study of intestinal microflora].

Intestinal microflora changes in ten adult and healthy subjects after storage of specimen with different modalities, temperatures and times were evaluated quantitatively and qualitatively. Aerobic components (Enterobacteriaceae, Enterococcus, Staphylococcus and Bacillus spp.) did not show considerable variations of concentration in all maintenance conditions.

The inhibitory effect of D-glucosamine on thymidine kinase in chick embryo retinas and HeLa cells.

D-Glucosamine markedly inhibits thymidine incorporation into the TCA-insoluble fraction and thymidine kinase activity in HeLa cells. Both the inhibitory effects are also observed in isolated retinas of chick embryos. In this case the inhibitory effects are age-dependent and the magnitude of the responses decreases with embryonic development.

The purification and properties of nucleoside phosphotransferase from mucosa of chicken intestine.

Nucleoside phosphotransferase (nucleotide: 3'-deoxynucleoside 5'-phosphotransferase, EC 2.7.1.

[In vitro activity of several cytostatic drugs against aerobic and anaerobic intestinal bacteria].

The human normal intestinal flora prevents the colonization of exogenous bacteria, maintaining a constant microecology: this property is called "colonization resistance". In leukemia patients antibiotics used for prevention and/or therapy of infectious episodes can alter the intestinal microecology, so that the gut can represent the trigger zone for generalized septicemia. Moreover cytotoxic drugs used in these patients can favour intestinal disturbances.

The effects of glucocorticoids on thymidine kinase and nucleoside phosphotransferase during development of chicken embryo retina.

Thymidine kinase in chick embryo retina reaches its highest values on the 8-10th day of development, then declines reaching the lowest value at hatching. The rate of DNA synthesis essentially follows this activity while, in contrast, nucleoside phosphotransferase increases progressively during development. Glucocorticoids at 5 X 10(-6) M lower the level of thymidine kinase in isolated retinas of chick embryo.

Behavior of a cell line derived from a mouse submaxillary adenocarcinoma during the initial 480 days in vitro.

A cell line was established from a transplantable adenocarcinoma, containing viral particles of the A and B type, drived from a tumor appearing spontaneously in the submaxillary region of a male mouse of the C3H/He strain. This line, after 480 days in vitro, did not change the original epithelial-like morphology, the viral expression, the membrane immunofluorescence and the degree of agglutination by various plant lectins. After 208 days of culture, the presence of up to 3 pairs of metacentric chromosomes appeared in about 55% of the cells.

Effect of neuraminidase and papain treatment on lectin-induced agglutination of Novikoff tumor cells and assay of lectin receptor activity of the glycopeptides released from the cell surface by papain.

Lectins, plant proteins that bind specific saccharide determinants, have been utilized to examine the effect of neuraminidase digestion on the structure and/or expression of oligosaccharide moieties present at the periphery of Novikoff ascites hepatoma cells. Five lectins were utilized: concanavalin A (Con A), specific for alpha-D-manno- or alpha-D-glucopyranosyl residues; wheat germ agglutinin, specific for 2-acetamido-2-deoxy-D-glucopyranosyl residues; Ricinus communis agglutinin I (RCAI), specific for D-glucopyranosyl residues; R. communis agglutinin II (RCAII), specific for D-galacto- or 2-acetamido-2-deoxy-D-galactopyranosyl residues; and soybean agglutinin, specific for 2-acetamido-2-deoxy-D-galactopyranosyl residues.

Viral expression, oncogenicity, and antigenicity of a mouse salivary gland tumor and two cell lines derived from it.

An in vitro cell line (SGT) derived from a mouse submaxillary gland adenocarcinoma (TGS) containing A and B viral particles maintained its oncogenicity only for newborn isogeneic hosts (C3H/He mice) immunosuppressed with antithymocyte serum. Inoculation into adult isogeneic animals did not cause tumor but provided partial protection against a challenge with TGS cells. The loss of oncogenicity for nonimmunosuppressed isogeneic hosts was accompanied by the acqusition of oncogenicity for adult, nonimmunosuppressed, xenogeneic hosts (golden hamsters) given subcutaneous inoculations of SGT cells on the back.