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Biomedical subjects

G H Smith

Publications and source records attributed to G H Smith.

At least 127 records · Page 7Linked to original sources
PubMed1982

Unconventional application of standard light and electron immunocytochemical analysis to aldehyde-fixed, araldite-embedded tissues.

A simple procedure for the immunocytochemical analysis of glutaraldehyde/formaldehyde-fixed, Araldite- or Epon-embedded tissues by either light or electron microscopy is presented. Retention of immunoreactive antigen in deplasticized sections was achieved by use of a low concentration of glutaraldehyde in the fixative in combination with a seldom-used plastic solvent. This protocol produced good ultrastructural preservation in tissues and large, high-quality, 2-micrometers thick, plastic-free sections. These semithin sections provided a level of structural and antigenic preservation, image resolution, and labeling intensity that surpassed all other conventional sectioning methods used for immunocytochemistry. The capacity to use a single tissue sample in studies designed for light and electron immunocytochemistry, in conjunction with existing autoradiographic and cytochemical techniques, makes this a very desirable method for routine tissue preparation in research and clinical applications.

Animals↗
PubMed1982

Dissociation of cytological and functional differential in virgin mouse mammary gland during inhibition of DNA synthesis.

Epithelial cells in mammary gland explants from mice assume a secretory appearance and synthesize the milk proteins, casein and alpha-lactalbumin, when cultured in the presence of insulin, hydrocortisone and prolactin. In cells from the glands of mature virgin animals such syntheses are known to require DNA synthesis. Addition of cytosine-beta-D-arabinofuranoside to the explant cultures suppresses both hormonally induced DNA synthesis and enhanced production of milk protein. To determine the level at which this block in terminal differentiation occurs, epithelial cell pellets were prepared from virgin mouse mammary gland explants cultured with various combination of insulin, hydrocortisone and prolactin, and subsequently examined by light and electron microscopy. We observed that the epithelial cells cultured in the presence of all three hormones developed fully, cytologically and ultrastructurally, even in the absence of DNA synthesis in vitro. Likewise, these cells were able to incorporate [3H]uridine into RNA efficiently and to incorporate amino acids into acid-precipitable polypeptides at levels equivalent to the untreated controls. However, immunoprecipitation of newly synthesized casein peptides showed that no new synthesis of casein occurred in cells prevented from synthesizing DNA. These data show uncoupling of cytological development and synthesis of milk protein in mammary explants from mature virgin mice inhibited from synthesizing DNA.

Animals↗
PubMed1981

The activities and intracellular distributions of enzymes of carbohydrate, lipid and ketone-body metabolism in lactating mammary glands from ruminants and non-ruminants.

1. The activities of several enzymes of carbohydrate, lipid, acetate and ketone-body metabolism were measured in lactating mammary glands from rats, mice, rabbits, guinea pigs, sows, sheep, cows and goats. The intracellular distributions of many of the enzymes were measured by fractional extraction. 2. Acetyl-CoA synthetase was predominantly cytoplasmic in rats and guinea pigs, but was more mitochondrial in the other species. The different location of this enzyme in rats and mice is discussed in relation to the disposal of reducing equivalents. 3. 3-Oxo acid CoA-transferase and acetoacetyl-CoA thiolase assayed at 600 microM-CoA were predominantly mitochondrial in all species investigated. Acetoacetyl-CoA thiolase assayed at 8 microM-CoA was predominantly cytoplasmic, except in rabbits and guinea pigs. Ruminants appeared to possess little, if any, of the cytoplasmic enzyme. 4. The activities and distributions of NADP-isocitrate dehydrogenase were consistent with a role in supplying cytoplasmic NADPH in ruminant tissue, and indicated that this system may also occur in guinea pigs.

Acetates↗
PubMed1981

Metronidazole in breast milk.

Breast milk concentrations of metronidazole were assayed in 3 women who had been treated with a single 2.0-g dose for trichomoniasis. Highest concentrations of the drug were found 2 and 4 hours after administration, and they declined over the next 12 to 24 hours. It appears that if breast-feeding is withheld for 12 to 24 hours after the dose, infants will be exposed to a greatly reduced amount of metronidazole. As the use of metronidazole in nursing mothers is currently not recommended, this may be the regimen of choice for the treatment of trichomoniasis in lactating women.

Female↗
PubMed1980

A new culture medium for human skin epithelial cells.

A new culture medium, NCTC 168, has been designed for human skin epithelial cells. This medium formulation was developed, by combining and testing at various concentrations, components of media NCTC 135 and 163, since a 1:1 mixture of these two media with 10% horse serum supplement was found to promote epithelial cell outgrowth from human skin explants. The buffer system in NCTC 168 maintains the pH of the medium between 7.0 and 7.2. In contrast to other media tested, NCTC 168 with 10% horse serum is capable of initiating and sustaining larger epithelial cell outgrowths. Explants in serum-supplemented NCTC 168 in the absence of feeder cells reproducibly yield confluent epithelial cell sheets apparently free of fibroblasts after only 19 to 28 days as compared with 5 weeks or longer for the other media tested. NCTC 168 also supports passage of human epithelial cells to the sixth subculture generation without feeder cells. Electron microscopy has shown the presence of desmosomes and tonofilaments in the passaged cells indicating the epithelial nature of the cells. The addition of epithelial growth factor, hydrocortisone and insulin at 5 ng per ml, 4 microgram per ml and 5 microgram per ml, respectively, did not appreciably enhance the growth of the epithelial cells.

Blood↗
PubMed1980

DNA binding and unwinding activities associated with intracytoplasmic a particles isolated from mouse mammary tumors.

Intracytoplasmic A particles (CAP), previously identified as probably cytoplasmic nucleocapsid precursor structures to mouse mammary tumour virus (MMTV), possess both DNA binding and DNA unwinding activities, CAP proteins bind to both single-stranded (ss)- and double-stranded (ds)DNA, with the ssDNA slightly preferred. This activity was linear over a 30-fold concentration of A particle protein and was not affected by NaCl concentrations as high as 0.6 M or pH changes over a wide range. DNA binding by CAP proteins was sensitive to heat or addition of sodium dodecyl sulphate (SDS) and was neutralized by pre-incubation of CAP with anti-MMTV p14, but not by anti-MMTV p27, p10 or anti-mouse casein. Incubation of CAP with dsDNA led to unwinding of the double helix as measured by its increased sensitivity to S1 nuclease digestion. This activity was also linear over a several-fold concentration of A particle protein and was heat labile. It was not inhibited by pre-incubation of CAP with either anti-MMTV p14 or with anti-MMTV, anti-MMTV p27 and anti-MMTV p10. DNA unwinding was inhibited by anti-A particle antiserum and to a lesser extent by anti-CAP p20-18.

Animals↗
PubMed1980

Night of terror.

Explore the source record for details and available documents.

Alabama↗
PubMed1979

Molecular relationship of the DNA and RNA of intracytoplasmic A particles to mouse and mammary tumour virus genomes.

We have directly tested the hypothesis that single-stranded cytoplasmic A particle-associated DNA (ss CAP DNA) is a murine mammary tumour virus (MMTV) proviral intermediate by hybridizing 125I-labelled ss CAP DNA to MMTV RNA or to MMTV complementary DNA (cDNA). 125I-labelled CAP DNA did not form duplexes with either MMTV RNA or MMTV cDNA. In contrast, CAP RNA hybridized readily with MMTV cDNA. CAP RNA contained all the MMTV virus sequences, but at lower concentrations than in MMTV virus particles. Single-stranded CAP DNA hybridized readily with mouse DNA from several sources. A study of the rate of hybridization of CAP DNA to cell DNA at various driver to probe ratios showed that its rate of hybridization is similar to that of tumour cell DNA reassociation. Further, in reassociation studies accelerated by using the phenol emulsion reassociation technique (PERT), CAP DNA originally isolated as single-stranded DNA was shown to reanneal (70%), to protect 125I-cell DNA to the same extent (67%) and to do so with kinetics of reassociation equivalent to that of mouse DNA. Although CAP DNA isolates were slightly enriched for MMTV specific sequences when compared to total cellular DNA, we conclude that the majority of ss CAP-associated DNA is equivalent to a random sample of total tumour cell DNA.

Animals↗
PubMed1979

A 'mini-residency' in drug information for the practicing pharmacist.

Continuing education "mini-residencies" in drug information services were sponsored by the University of Washington School of Pharmacy's Division of Continuing Education and the University of Washington Drug Information Service (DIS) in August of 1976, 1977, and 1978. Each mini-residency covered a two-week period (a total of 80 hours) and was divided into didactic and experimential sessions. The university's DIS was the major resource for the residents. The two-week residency was designed to provide education and experience in the areas of drug information retrieval, analysis, and dissemination. The program was assessed through pre- and post-testing and a midcourse evaluation session. The residency format of the program allowed practicing pharmacists to return to the university to develop their skills in the area of drug information. The article presents a model for other drug information pharmacists who may want to offer similar training programs.

Curriculum↗
PubMed1978

Immunological characterization of the low-molecular-weight DNA binding protein of mouse mammary tumor virus.

p14, a low-molecular-weight MMTV protein previously identified as having DNA-binding properties and encoded by the gag region of the MMTV genome, was purified by affinity chromatography on DNA-sepharose. Immunological characterization of the purified protein showed that MMTV p14 shares no cross-reactivity with gp52, gp36 and p10, antigens associated with the MMTV envelope, nor with p27 antigen found in the virion core. Purified MMTV p14 did show cross-reactivity with purified intracytoplasmic A particles, supporting the concept that A particles are morphological precursors to MMTV cores. In addition, shared antigenic determinants between intracytoplasmic A particles and MMTV p27, p20 and p10 were demonstrated. MMTV p14 did not cross-react with the low-molecular-weight DNA-binding proteins of MuLV or of type-C or -D viruses of higher mammals.

Animals↗