Modulation of oncogene expression by epidermal growth factor and gamma-interferon in A431 squamous carcinoma cells

Epidermal growth factor (EGF) acts, in a dose dependent manner, as both a mitogen and an inhibitor of growth of the A431 squamous carcinoma cell line. gamma-interferon (IFN) also inhibits A431 cell growth. The dual effects of EGF on A431 growth and expression of the oncogenes, EGF receptor (EGFR) and Ha-ras, were evaluated with or without gamma-IFN. A mitogenic level (10pM) of EGF had no effect on expression of EGFR 10 kb mRNA or protein. gamma-IFN combined with 10pM EGF caused an initial drop in EGFR mRNA not reflected at the protein level; at 72 hours, the level of EGFR 10kb mRNA rose and inhibition of cell growth was observed. Treatment with a cytostatic amount (10nM) of EGF resulted in decreased expression of EGFR 10kb mRNA and protein within 24 hours; combined treatment with gamma-IFN caused rapid cell death. Expression of Ha-ras mRNA paralleled that of EGFR mRNA upon treatment with 10pM EGF and/or gamma-IFN, but differed with 10nM EGF.

Multiple hormones regulate angiotensinogen messenger ribonucleic acid levels in a rat hepatoma cell line

Angiotensinogen is regulated by both hormones and changes in cardiovascular and electrolyte status. We have used the Reuber H35 (H4IIE) rat hepatoma cell line to study the regulation of angiotensinogen mRNA levels by dexamethasone, aldosterone, L-T3, and 17 beta-estradiol. Using the Acc I (1097 basepairs) fragment of our angiotensinogen cDNA clone, we have studied, by Northern and slot blot analysis, the accumulation of angiotensinogen mRNA in this cell culture system. Angiotensinogen mRNA of approximately 1800 bases was identified in these cells. It was identical in size to angiotensinogen mRNA from rat liver. Cells grown in medium containing serum depleted of thyroid and steroid hormones for up to 72 h showed a progressive decrease in angiotensinogen mRNA. Dexamethasone treatment resulted in a time- and dose-dependent increase in angiotensinogen mRNA. The half-maximal response occurred at 10(-9) M dexamethasone, with a maximal response of approximately 4-fold (serum-free conditions). Aldosterone induced a dose-dependent increase in mRNA. Half-maximal levels were obtained at 5 X 10(-8) M. Competition studies using the glucocorticoid antagonist RU38486 (Roussel-UCLAF) confirmed that dexamethasone was acting through the glucocorticoid receptor and suggested that aldosterone was acting through the same receptor. L-T3 treatment caused a dose and time-dependent increase in angiotensinogen mRNA levels. The half-maximal response occurred at 5 X 10(-8) M, and the maximal response was a 2-fold increase. Combined treatment with dexamethasone and L-T3 triiodothyronine resulted in a synergistic increase in angiotensinogen mRNA levels. 17 beta-Estradiol failed to elicit a change in angiotensinogen mRNA levels consistent with the observation that these cells lack estrogen receptors. Our results indicate that hepatic angiotensinogen mRNA levels are regulated in a complex fashion by several hormones. These cells provide a useful system for studying the hormonal regulation of the angiotensinogen gene.

The effect of intramammary antibiotic therapy at calving on udder health traits

The effect of intramammary antibiotic therapy at calving on mastitis infection prevalence, linear score milk somatic cell count, and milk NAGase activity, 30 d postpartum, and on milk production, 90 to 120 d postpartum, was tested. Cows (n = 175) were split into treatment and control groups at drying off. All cows received commercial dry cow therapy. At calving, treated cows received commercial lactating cow therapy in all quarters after the first two milkings; control cows were not treated. Composite milk samples were aseptically collected from all cows at drying off, calving, and 30 d postpartum. Udder health traits: linear score milk SCC, NAGase activity, and bacterial content in milk, were determined on all samples. The first three DHI milk weights were recorded for all cows. Treatment and control cows had similar prevalences of intramammary infections during the dry and 30-d postpartum periods. Least squares means of linear score milk SCC and NAGase activities were similar at drying off and calving. Cell count scores were similar between groups; NAGase activities were higher in control cows at 30 d postpartum. Control cows tended to produce more milk postpartum. Results demonstrated no advantage of intramammary therapy at calving in improving milk production or udder health.

Prenatal diagnosis of neuronal ceroid-lipofuscinoses

We report on the successful prenatal diagnosis of the late infantile "Jansky-Bielschowsky" variant of the neuronal ceroid-lipofuscinoses (NCL). The fetus was studied at 16 weeks of gestation because of an affected sib. Uncultured amniotic fluid cells were studied by conventional electron microscopic techniques. About one-third of a subpopulation of dark, elongated cells contained one or more deposits of curvilinear cytosomes bound by a single unit membrane. These findings were considered typical of the late infantile variant of NCL. After delivery at term, a skin punch biopsy and a buffy coat preparation from the baby were examined and found to have similar characteristic inclusions, which confirmed our prenatal diagnosis.

Microbial growth associated with granular activated carbon in a pilot water treatment facility

The microbial dynamics associated with granular activated carbon (GAC) in a pilot water treatment plant were investigated over a period of 16 months. Microbial populations were monitored in the influent and effluent waters and on the GAC particles by means of total plate counts and ATP assays. Microbial populations between the influent and effluent waters of the GAC columns generally increased, indicating microbial growth. The dominant genera of microorganisms isolated from interstitial waters and GAC particles were Achromobacter, Acinetobacter, Aeromonas, Alcaligenes, Bacillus, Chromobacterium, Corynebacterium, Micrococcus, Microcyclus, Paracoccus, and Pseudomonas. Coliform bacteria were found in small numbers in the effluents from some of the GAC columns in the later months of the study. Oxidation of influent waters with ozone and maintenance of aerobic conditions on the GAC columns failed to appreciably enhance the microbial growth on GAC.

Fine structure of cutaneous nerves in ganglioside storage disease

Skin punch biopsies of six children suffering from infantile or late onset Tay-Sachs disease, juvenile Sandhoff disease, or GM gangliosidosis type I, contained axons which, when viewed with the electron microscope, were distended by large amorphous black deposits. These are nonspecific residual bodies. Their large numbers indicate severe disturbance of the nerve cell and may be part of the dying back process. The three cases with Tay-Sachs disease had also axonal zebra or complex membranous bodies which appeared to be specific. Cytoplasmic vacuolation of other cells was a feature in the patient with GM1 gangliosidosis. Biopsies of three parents were negative.

Skin punch biopsies and lymphocytes in the diagnosis of lipidoses

Skin punch biopsies and buffy coats of white blood cells were examined electron microscopically in patients suffering from a variety of storage diseases. No specific abnormalities could be detected in Gaucher's disease and adreno-leucodystrophy. While characteristic deposits were found in cutaneous nerves in globoid and metachromatic leucodystrophy, this method was deemed inferior to sural nerve biopsy. In gangliosidoses, on the other hand, pathognomonic membranous cytoplasmic bodies were common in axons of cutaneous nerves, and in generalized gangliosidoses marked vacuolation of many other cells was prominent. Specific deposits were found in various cells in skin punch biopsies and in lymphocytes of children suffering from ceroid lipofuscinoses, and in lymphocytes of their parents. This constitutes the easiest diagnostic laboratory procedure in such cases.

Bacteriophages of Clostridium botulinum

Temperate bacteriophages of diverse morphology were demonstrated by electron microscopy in toxigenic cultures of Clostridium botulinum. The 41 strains examined included 23 type E and multiple representatives of all other types. Cultures induced with mitomycin-C generally gave better yields, but phages were also demonstrable in untreated cultures.A provisional grouping of toxigenic types into four categories is suggested, based mainly upon associated phage patterns. Group 1 comprises types A, B, and F (all proteolytic), many of whose cultures showed an icosahedral contractile phage; others contained a "bullrushy" phage with elongated head and long flexible tail; some strains yielded both. Group 2, types B and F (non-proteolytic), were associated with icosahedral contractile phages; the latter also had an octahedral flexible phage. Group 3, types C and D, yielded conspicuously large phages with octahedral heads and very long sheathed tails. One type C strain produced a long-tailed icosahedral phage. Type E phages constituted group 4. These were icosahedral with tails generally contracted but sometimes flexible, often accompanied by superfluous sheathed tail-like structures resembling certain bacteriocins. Although non-toxigenic "OS" mutants of types A, B, E, and F were phageless, two non-toxic type E strains yielded phages. The possible role of lysogeny in the toxigenicity of certain types of this species is likely to prove difficult to elucidate.