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L W Kam

Publications and source records attributed to L W Kam.

5 recordsLinked to original sources
PubMed2000

CD3zeta and CD28 down-modulation on CD8 T cells during viral infection.

Down-modulation of CD3zeta expression on CD8 T lymphocytes occurs, independently of other T-cell receptor (TCR)-CD3 components, in tumor-infiltrating lymphocytes, human immunodeficiency virus infection, and autoimmune disease. These associations suggest that it might be related to chronic antigenic stimulation. CD3zeta down-modulation was found, however, in CD8 T cells that proliferate in response to acute viral infections. In 3 otherwise healthy donors with acute gastroenteritis, infectious mononucleosis, and Epstein-Barr virus/cytomegalovirus/mononucleosis, 30% to 60% of circulating CD8 T cells had down-modulated CD3zeta to below the level of detection. The CD3zeta-T cells were also CD28- but expressed the activation markers HLA-DR and CD57. CD3zeta-CD28- T cells are effector CTL because they express perforin and produce IFN-gamma, but not IL-2, on activation and contain the viral-specific cytotoxic T lymphocyte (CTL). However, CD3zeta-CD28-T cells generally do not express CD25 after anti-CD3 and anti-CD28 stimulation and are not cytotoxic until they are cultured with IL-2 overnight. Cytotoxicity coincides with the re-expression of CD3zeta but not CD28. Down-modulation of CD3zeta and CD28 on effector CTL may control CTL triggering and proliferation to prevent immunopathogenesis.

CD28 Antigens↗
PubMed1990

Internal hemorrhoids: diagnosis with double-contrast barium enema examinations.

The authors retrospectively studied 43 patients suspected of having internal hemorrhoids at double-contrast barium enema examination. At endoscopy, 24 patients (56%) had internal hemorrhoids, four (9%) had other pathologic lesions in the rectum without evidence of hemorrhoids, and 15 (35%) had no reported abnormalities in the rectum. Internal hemorrhoids were found at endoscopy in 10 of 20 patients (50%) with lobulated folds extending 3 cm or less from the anorectal junction and 10 of 13 patients (77%) with multiple submucosal nodules. However, no patients with these characteristic radiographic findings were found to have other pathologic lesions in the rectum that had been mistaken for hemorrhoids at barium enema examination. Conversely, three of four patients with lobulated folds extending more than 3 cm from the anorectal junction and one of six patients with solitary nodules had proctitis or rectal neoplasms. Thus, specific criteria are suggested for the diagnosis of internal hemorrhoids on double-contrast barium enema examinations. Suspected hemorrhoids that do not fulfill these criteria should be evaluated endoscopically to rule out other more serious pathologic lesions in the rectum.

Barium Sulfate↗
PubMed1985

Diurnal temperature patterns of early lactating cows with milking parlor cooling.

Ten cows in early stages of lactation (less than 100 days postpartum) were used to test the effect of sprinkler/fan cooling on vaginal temperature patterns. Cows were assigned to two groups matched according to milk production. The trial was divided into three periods: period 1, when one group was treated and the other group was not, period 2, when neither group was treated, and period 3, when treatment was switched from period 1 between groups. Treatment consisted of forced air misting in a premilking holding pen, fan cooling during milking, and forced air-sprinkling in a postmilking holding area. Weather conditions were measured by dry bulb, wet bulb, and black globe temperatures. Black globe temperatures in pre- and postmilking holding areas were used to estimate treatment magnitude. All measures were obtained through radiotelemetry at 15-min intervals for 31 days. Animals were milked twice a day. Animals spent an average of 140 min in treatment at each milking. In both morning and afternoon milking, treatment caused a transient increase of body temperature. However, this was followed in the afternoon by low vaginal temperatures for 1 to 2 h beyond treatment with lower temperatures throughout the day.

Air Conditioning↗
PubMed1984

Effect of lactation on diurnal temperature patterns of dairy cattle in hot environments.

Vaginal temperature patterns were obtained from 15 Holstein cows through radiotelemetry. Animals were divided into three groups with five animals per group: 1) cows in early lactation, less than 100 days postpartum, 2) cows in late lactation, greater than 240 days postpartum, and 3) dry cows. Animal temperatures, dry bulb, wet bulb, and black globe temperatures were monitored every 15 min for 17 days. Analysis of variance showed no significant difference for daily mean vaginal temperature between lactation groups. However, on hotter days, lactating cows had higher temperatures than dry cows. Daily mean vaginal temperatures of cows in early lactation were correlated with daily mean dry bulb temperature, black globe temperature, and relative humidity. Comparison of group temperature patterns isolated differences to specific times of day. In groups with early and late lactations, temperatures were lower in either group after milking. Vaginal temperatures were higher in lactating cows than in dry cows through most of the day. Results were 1) diurnal temperature patterns differ among groups; 2) lactating cows are sensitive to environmental changes; and 3) animal management can affect patterns of animal temperature.

Animals↗