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Biomedical subjects

D L Walters

Publications and source records attributed to D L Walters.

26 records · Page 2Linked to original sources
PubMed1980

Effect of antineoplastic drugs on human leukocyte-mediated cytotoxicity against herpes simplex virus infected cells.

We evaluated the effect of five antineoplastic drugs on the ability of human leukocytes to destroy herpes simplex virus (HSV) infected target cells in the presence of antibody (antibody-dependent cellular cytotoxicity) and in its absence (natural killer cytotoxicity). Leukocytes from healthy volunteers were separated into macrophages, polymorphonuclear leukocytes, and lymphocytes. Adriamycin, cyclophosphamide, prednisone, procarbazine, and vincristine, at various concentrations and incubation periods, were tested for their effects on the natural killer and antibody dependent cellular cytotoxicity of macrophages, lymphocytes, and polymorphonuclear lymphocytes in a 51Cr release microcytotoxicity assay against HSV-infected cells. All drugs at therapeutic concentrations inhibited natural killer and antibody dependent cellular cytotoxicity; an exception was cyclophosphamide, which did not inhibit the natural killer cytoxicity of lymphocytes. The antibody dependent cellular cytotoxicity of macrophages and polymorphonuclear leukocytes appeared to be more than that of lymphocytes. The results of short incubation (2 hours) of the drug with either effector cells or target cells, followed by drug removal, suggests that the drug effect occurred early and predominantly at the effector cell level. Antineoplastic drugs had an inhibitory effect on natural killer and antibody dependent cellular cytotoxicity against HSV-infected cells. This inhibitory action may partially explain the increased susceptibility of patients receiving chemotherapy to developing viral infections.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1979

Murine antibody-dependent cellular cytotoxicity to herpes simplex virus-infected target cells.

Freshly collected peritoneal cells (PC) and cultured spleen cells (SC) (but not fresh SC) from nonimmune mice could mediate antibody-dependent cellular cytotoxicity (ADCC) against herpes simplex virus (HSV)-infected cells in the presence of mouse or human sera containing antibody to HSV. PC also demonstrated variable natural killer cell cytotoxicity to infected cells. Both PC and cultured SC required high concentrations of antibody and high effector to target cell ratios for optimal ADCC. The time kinetics of the reaction appeared to depend on the state of activation of the effector cells. In both PC and SC populations, ADCC activity was limited to adherent cells, and was profoundly inhibited by particulate latex or silica. The murine effector cell found in PC and SC able to mediate ADCC to HSV-infected cells appears to be a macrophage.

Animals↗
PubMed1978

Rotavirus in travelers' diarrhea: study of an adult student population in Mexico.

The role of rotavirus in adult diarrhea was evaluated in 165 students attending a Mexican university. Students were divided into three groups: newly arrived summer students from the United Sttes, regular students from the United States, and Mexican and Venezuelan students. Ninety-one students with diarrhea and 74 corresponding, matched, asymptomatic control students were included in the study. The frequency of rotavirus in stools was determined by electron microscopy with use of the pseudoreplica technique. Twenty-five percent of those who were ill and 12% of the controls had rotavirus in their stools. A significantly (P less than 0.05) greater number of newly arrived United States summer students with diarrhea had rotavirus in their stool than did matched controls (26% vs. 3%). There was no significant difference in rate of recovery of bacterial pathogens from rotavirus-positive and rotavirus-negative stools (52% vs. 53%) from students with diarrhea. Although significantly more rotavirus was identified from ill American summer students than from controls, the role of rotavirus as a cause of diarrhea in these students could not be established in all cases since bacterial pathogens were also commonly found in stool.

Diarrhea↗
PubMed1978

Human colostral cytotoxicity: I. Antibody-dependent cellular cytotoxicity against Herpes simplex viral-infected cells mediated by colostral cells.

Human colostral cells in combination with antibody were able to destroy Herpes simplex virus-infected cells (Antibody-dependent cellular cytotoxicity--ADCC) while demonstrating very low spontaneous (non-antibody mediated) cytotoxicity (SCT). The colostral cells involved in ADCC required a high effector to target ratio, were mononuclear, adherent and totally inhibited by latex particles. These results demonstrate that a subpopulation of human colostral macrophages can mediate ADCC against virus-infected target cells. The biologic implications of intact colostral cell ADCC and low SCT in regard to protecting the neonate from infection and maternal cell mediated gastrointestinal damage are discussed.

Antibody-Dependent Cell Cytotoxicity↗
PubMedDate not supplied

A comparison of fluorescence versus chemiluminescence detection for analysis of the fluorescamine derivative of histamine by HPLC.

Fluorescence and chemiluminescence detection were compared for HPLC analysis of the fluorescamine derivative of histamine. The kinetic behaviour of the chemiluminescent response for the derivative was characterized in a static system. An HPLC method was optimized for the derivative using fluorescence detection. Fluorescence detection was linear over the range of 166-1666 pg on column for the fluorescamine-histamine derivative with a limit of detection of 13 pg on column. Using a detector designed for optimal use with chemiluminescence, the chemiluminescence response of the fluorescamine derivative was linear over a range of 1.66-16.6 ng on column with a limit of detection of 1.0 ng on column. These results exemplify a case in which superior detectibility is provided by fluorescence over chemiluminescence, and contradicts many reports comparing fluorescence to chemiluminescence. The authors conclude that chemiluminescence should be considered when indicated by conditions established for separation that are favourable for the observation of chemiluminescence. These conditions include sufficiently low excitation energies corresponding to an excitation maximum greater than 400 nm, favourable dipole character of analytes, mobile phases of high organic content, and an appropriate pH of the mobile phase.

Chromatography, High Pressure Liquid↗