Recovery of protein synthesis after heat shock: prior heat treatment affects the ability of cells to translate mRNA.

A mild heat shock at 35 degrees C, which induces heat shock gene expression, greatly enhances survival and the recovery of protein synthesis in Drosophila cells after a higher temperature heat shock. The 35 degrees C treatment is also effective in preventing heat-induced developmental defects in pupae. We show here that the major larval mRNAs are present in approximately normal (25 degrees C) concentrations after a 40.

Effects of multiple membranes on measurements of cell surface dynamics by fluorescence photobleaching.

Fluorescence photobleaching recovery curves on a pair of membranes at various separations were calculated from a detailed knowledge of the variation in relative illumination areas and intensities as well as in relative contributions to the collected intensity with membrane separation. The observed diffusion coefficients were found to be relatively insensitive to membrane separation in all cases. Only for membranes with very different mobilities are there significant differences in fractional recoveries.

Evaluation of a finger-stick specimen collection method for seroepidemiology of antibody to hepatitis A virus.

A finger-stick swab method of collecting blood specimens was shown to compare favorably with the conventional venipuncture method in serological determinations of antibody to hepatitis A virus by radioimmunoassay.

Immunologic phenomena in the effusive form of feline infectious peritonitis.

The effusive form of feline infectious peritonitis (FIP) was reproduced by injecting 12- to 16-week-old kittens intraperitoneally with a cell-free inoculum derived from the tissues of infected cats. The kittens used for the study were either positive for FIP virus-reacting antibodies before inoculation or they were seronegative. Seropositive kittens were obtained from a cattery where the natural infection was enzootic, and seronegative kittens were obtained from a specific-pathogen-free cattery.

An assessment of the airborne route in hepatitis B transmission.

The experimental and epidemiologic evidence for airborne transmission of hepatitis B is inconclusive and our efforts to detect airborne HBsAg or blood in environments where hepatitis B transmission occurs have been uniformly unsuccessful. In the specific areas investigated: dialysis centers, laboratories, and dental operatories, other major routes of transmission that can explain the spread of hepatitis B invariably are present. Therefore, while airborne taansmission is theoretically possible and probably has occurred, at this time its contribution to the overfall hepatitis B problem cannot be quantitated.

Resonance Raman spectra of cytochrome c oxidase. Excitation in the 600-nm region.

The resonance Raman (RR) spectra of oxidized, reduced, and oxidized cyanide-bound cytochrome c oxidase with excitation at several wavelengths in the 600-nm region are presented. No evidence is found for laser-induced photoreduction of the oxidized protein with irradiation at lambda approximately 600 nm at 195 K, in contrast to the predominance of this process upon irradiation in the Soret region at this temperature. The Raman spectra of all three protein species are very similar, and there are no Raman bands which are readily assignable to either cytochrome a or cytochrome a3 exclusively.

Air sampling for hepatitis B surface antigen in a dental operatory.

Forty samples of air with a mean sample volume of 104 liters were collected during the treatment of patients whose blood was positive for HBsAG: no samples contained HBsAG and occult blood. These findings suggest that, if environmentally mediated transmission of hepatitis B occurs in the dental operatory, it is more likely to occur through contact with contaminated surfaces than through the airborne route.

Physicochemical characterization of 1,2-diphytanoyl-sn-glycero-3-phosphocholine in model membrane systems.

We report here on a series of studies aimed at characterization of the structural and dynamical properties of the synthetic lipid diphytanoyl phosphatidylcholine, in multilamellar dispersions and vesicle suspensions. The lipid exhibits no detectable gel to liquid crystalline phase transition over a large temperature range (-120 degrees C to +120 degrees C). Examination of proton nuclear magnetic resonance (NMR) free induction decays obtained from multilayer dispersions of diphytanoyl phosphatidylcholine provided an estimate of the methylene proton order parameter.

Galapagos hydrothermal mounds: stratigraphy and chemistry revealed by deep-sea drilling.

The Galápagos mounds sea-floor hydrothermal system is at least 300,000 years old and once produced manganese-poor sediments, which nearly blanketed the area of the present mounds field. Present-day mound deposits are limited manganese-rich exposures, suggesting that the system has changed from rock-to water-dominated and has diminished in intensity with time.

Growth characteristics of atypical mycobacteria in water and their comparative resistance to disinfectants.

With the increasing significance of group IV atypical mycobacteria as etiological agents in a variety of infections, studies were conducted to determine their growth capabilities in water and their comparative resistance to disinfectants used to decontaminate hospital equipment. Isolates of Mycobaterium chelonei (TM strains) from peritoneal fluids of patients and peritoneal dialysis machines were able to multiply in commercial distilled water, with generation times at 25 degrees C ranging from 8 to 15 h. Levels of 10(5) to 10(6) cells per ml were attained, and these stationary-phase populations declined only slightly over a 1-year period.

Yeast mutant, rna 1, affects the entry into polysomes of ribosomal RNA as well as messenger RNA.

The entry of newly labeled ribosomal subunits and mRNA into polysomes was examined in the yeast mutant rna1. The entry of both types of RNA into polysomes is inhibited rapidly at the restrictive temperature. Analysis of the labeling of the ATP pool and the kinetics of synthesis and processing of mRNA at the restrictive temperature leads to the conclusion that the primary defect in the mutant affects transport of both ribosomes and messenger across the nuclear membrane.

The effects of the thermal prephase transition and salts on the coagulation and flocculation of phosphatidylcholine bilayer vesicles.

Absorbance measurements of sonicated dipalmitoyl phosphatidylcholine vesicles reveal two aggregation processes: flocculation and coagulation. Flocculation is only observed for samples in monovalent cationic salt solutions or in salt-free suspensions. This process is abolished in the presence of di- or trivalent cations.

Evaluation of a finger prick blood collection method for the seroepidemiology of hepatitis B.

A finger prick-swab method of blood specimen collection was qualitatively and quantitatively compared with the conventional venipuncture method for HBsAg and anti-HBs determinations by radioimmunoassay (RIA). The new method consisted of pricking the finger, collecting 0.1-0.

Viral hepatitis B: aspects of environmental control.

In recent years it has become increasingly evident that viral hepatitis type B is a major disease problem among patients and/or health professionals associated with environments such as hemodialysis centers, dental operatories, clinical laboratories, and institutions for the mentally retarded. Studies have incriminated the intramural environment as well as specialized equipment and procedures as important factors in disease transmission. With hepatitis B surface antigen (HBsAg) as a marker of potentially infectious blood or body fluids such as saliva, it is possible to assess the environmental role in transmission of hepatitis B by use of a swab-rinse technique coupled with radioimmune assay.

More on the motional state of lipid bilayer membranes: interpretation of order parameters obtained from nuclear magnetic resonance experiments.

Proton and deuterium order parameters measured for the liquid crystalline phase of unsonicated lipid bilayer membranes are interpreted in terms of two motions: (i) chain reorientation and (ii) chain isomerization via kink diffusion. The observed order parameters are found to be compatible with angular deflections of the chain of about 50 degrees with respect to the bilayer normal, coupled with a probability of trans orientation of a methylene segment in the upper part of the chain of about 0.8-0.

A method for establishing cell lines from Drosophila melanogaster embryos.

A simple method is presented for establishing continuous cell lines from Drosophila melanogaster embryos. Subculturing is performed after the first 8 weeks and at 2-week intervals thereafter. Initial plating densities of 5 x 10(4) to 5 x 10(5) cells per cm2 are required for maintaining the subcultures.

[Malignant mediastinal lymphoblastic lymphoma with t-cell ALL (author's transl)].

29 cases of T-cell derived lymphoblastic lymphoma and T-ALL have been analyzed. There is a striking prevalence of the male sex. In the peripheral blood we often find initially an excessive number of white blood cells combined with normal values for the other constituents in about half of the patients; This may be an expression for the rapid occurrence of leukaemia in T-cell lymphosarcoma.

Ribosomal subunit entry into polysomes in yeast.

The kinetics of entry of newly synthesized 40 S and 60 S ribosomal subunits into yeast polysomes is described. The entry times for 40 S and 60 S subunits were found to be 3 and 8 min, respectively. The kinetics of entry of 40 S subunits into large polysomes is found to be different from the kinetics of entry of 60 S subunits into large polysomes.

Hepatitis B surface antigen in saliva, impetiginous lesions, and the environment in two remote Alaskan villages.

A study was conducted in an area of hepatitis B hyperendemicity to determin whether contact with infective bodily secretions or contaminated environmental surfaces could be involved in the transmission of the hepatitis B virus. Hepatitis B surface antigen was detected in gingival swab, saliva, and impetiginous lesion exudate samples from children. Hepatitis B surface antigen also was found in swab samples of surfaces frequently touched or placed in the mouth.