The changes in thrombocyte proteins during 22 degrees C storage of platelet concentrates (PC) were studied. To prepare a reference protein "map" of stored PC, platelet samples were taken on days 1, 7, and 21. The platelet proteins were separated by isoelectric focusing (first-dimension) followed by second-dimension polyacrylamide gradient gel electrophoresis with sodium dodecylsulfate (2D). The silver-stained gels were analyzed by computer to obtain a composite map of stored PC proteins. The pattern seen on day 1 changed during 7 days of storage, with 30 proteins increasing or decreasing in spot density. In general, the spot density for lower-molecular-weight proteins increased, whereas that for higher-molecular-weight proteins decreased. Membrane proteins of intact fresh and stored platelets were labeled with 3H using sodium metaperiodate-[3H]NaBH4 and with 125I using lactoperoxidase-H2O2. A comparison on the fluorographs of 2D gels of [3H]NaBH4-labeled platelet proteins showed several protein spots in the stored Day 7 sample that had not been seen in the Day 1 sample. Similarly, for the autoradiographs, several 125I-labeled proteins detected in Day 7 PC were not seen in the Day 1 samples. The results provide evidence that platelet proteins are altered during PC storage and that these changes involve platelet membrane proteins.

Blood Platelets↗

PubMedDate not supplied

Stability of genetic determination from age 2 to age 9: a longitudinal twin study.

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Body Constitution↗

PubMedDate not supplied

Adherence of Helicobacter pylori to gastric carcinoma cells: analysis by flow cytometry.

An in vitro assay using immunofluorescence and flow cytometry for quantitative assessment of the adherence of Helicobacter pylori to cultured human gastric carcinoma (KATO III) cells was developed. Adherence was rapid, saturable, energy dependent, mannose resistant, and significantly inhibited by fetuin, a glycoprotein containing N-acetylneuraminyllactose. Pretreatment of KATO cells with neuraminidase from Clostridium perfringens, however, did not reduce adherence of H. pylori. Ultrastructurally, adherent cells of H. pylori were associated with indentations of KATO cell membranes. KATO cells should prove useful in the investigation of mechanisms of adherence of H. pylori to mammalian cells. Ultimately, this flow cytometric assay may be helpful in assessment of the adherence of laboratory strains of H. pylori directly to surface mucous cells dissociated from biopsied human gastric tissue.

Bacterial Adhesion↗

PubMedDate not supplied

Cardiovascular response patterns and speech: a study of air traffic controllers.

The present study examined the relationship between cardiovascular (CVS) response and speech among air traffic controllers (ATCs). During two one-hour work sessions continuous EKG, ear pulse, and audio recordings were obtained individually from 24 male ATCs. In one session the controller actively controlled aircraft, while in the other he worked in a support/coordinator position. Session time in both conditions was partitioned on the basis of audio recordings into four mutually exclusive activities: Radio/Phone Talk, Radio/Phone Listening, Casual Talk, and Silence. Change in cardiovascular response pattern as a function of these activities, as well as the influence of a series of moderator variables on cardiovascular response, was assessed by examining heart rate (HR) and the EKG R-wave to ear pulse interval (RPI) relative to a pre-session baseline. The RPI index was employed as a means of unobtrusively tracking blood pressure on a beat-by-beat basis. Although reliable, the overall changes in CVS response were modest. Speech-associated reactivity was expressed exclusively by the RPI index. HR changes were not evident in response to speech, rather, the HR index appeared to be most sensitive to situational demand. Discrepancies between the present pattern and magnitude of speech-associated CVS response and those reported previously are discussed in terms of the nature of speech in laboratory versus field settings and measurement methodologies.

Adult↗

PubMedDate not supplied

Structure, function and localization of Helicobacter pylori urease.

Helicobacter pylori is the causative agent of most cases of gastritis. Once acquired, H. pylori establishes chronic persistent infection; it is this long-term infection that, is a subset of patients, leads to gastric or duodenal ulcer, gastric cancer or gastric MALT lymphoma. All fresh isolates of H. pylori express significant urease activity, which is essential to survival and pathogenesis of the bacterium. A significant fraction of urease is associated with the surface of H. pylori both in vivo and in vitro. Surface-associated urease is essential for H. pylori to resist exposure to acid in the presence of urea. The mechanism whereby urease becomes associated with the surface of H. pylori is unique. This process, which we term "altruistic autolysis," involves release of urease (and other cytoplasmic proteins) by genetically programmed autolysis with subsequent adsorption of the released urease onto the surface of neighboring intact bacteria. To our knowledge, this is the first evidence of essential communal behavior in pathogenic bacteria; such behavior is crucial to understanding the pathogenesis of H. pylori.

Bacterial Proteins↗