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Biomedical subjects

K Chow

Publications and source records attributed to K Chow.

32 records · Page 2Linked to original sources
PubMed1993

Interaction between T cells and murine acquired immunodeficiency virus superantigen: effect of second signal on T cell reactivity to the MAIDS virus superantigen.

A murine acquired immunodeficiency (MAIDS) virus transformed B cell line, B6-1710, was shown to express superantigen activity and stimulate T cell hybridomas to produce IL-2. However, T cell clones and lines from which B6-1710 reactive hybridomas were established failed to proliferate upon stimulation with B6-1710, while B6-1710 cells were capable of presenting bacterial superantigen to stimulate both T cell hybridomas and clones. Proliferative response of T cells to MAIDS virus superantigen could be detected by the addition of the pharmacological agent phorbol myristate acetate (PMA). Thus, B6-1710 seems to lack a stimulatory activity necessary for the proliferative response of T cells to the MAIDS viral superantigen. In the analysis of the response of naive splenic T cells to the MAIDS superantigen, T cells recovered from a culture stimulated with B6-1710 cells in the presence of PMA showed no dominant TCR V beta chain usage, while cells recovered from a culture stimulated with B6-1710 alone were dominated by T cells expressing V beta 5, 11, and 12 TCR chains. These results suggest that T cells bearing a majority of TCR V beta chains are capable of responding to B6-1710 superantigen. The avidity of interaction between T cells and viral superantigen may differ significantly among T cells and those T cells exhibiting weak interaction with MAIDS virus superantigen may require additional signals, such as PMA, for an in vitro proliferative response to B6-1710 cells.

Animals↗
PubMed1993

Effects of enteric parasitoses and HIV infection upon small intestinal structure and function in patients with AIDS.

We compared, retrospectively, the effects of infection in jejunal mucosa with the protozoa cryptosporidia or microsporidia and with the human immunodeficiency virus (HIV) upon mucosal structure and absorptive function in 29 AIDS patients. The presence or absence of protozoal infection was confirmed by transmission electron microscopy. Villus blunting and crypt hyperplasia were seen mainly in the parasite-infected groups, although two patients without parasites also had shortened villi. Absorptive functions, including disaccharidase-specific activities and D-xylose absorption, closely paralleled the degree of small intestinal alteration. Evidence of HIV-infected cells in jejunal mucosa was examined by RNA in situ hybridization and by antigen-capture ELISA of mucosal homogenates. We found evidence of HIV in almost half the patients, which did not correlate with intestinal injury or diminished absorption.

AIDS-Related Opportunistic Infections↗
PubMed1993

Prospective study of the aetiology of adult community acquired bacterial pneumonia needing hospitalisation in Singapore.

A prospective survey of 96 consecutive adult patients with community acquired pneumonia requiring hospitalisation was carried out at National University Hospital, Singapore. Causative pathogens were identified in 58% of patients. Mycobacterium tuberculosis was the most common pathogen (21%), followed by Streptococcus pneumoniae (12%), Haemophilus influenzae (5.2%), Mycoplasma pneumoniae (5.2%) and Staphylococcus aureus (4.2%). Gram-negative organisms (apart from Haemophilus influenzae) were found in 10% of pneumonia patients. More than half of the patients had pre-existing illness, the most common was diabetes mellitus (21%).

Adolescent↗
PubMed1989

Gallstone recurrence after cholecystolithotomy.

Surgical cholecystostomy is performed often at our institution for emergent management of acute calculous cholecystitis in high-risk elderly patients. Gallstones are removed either during surgery or by subsequent radiologic manipulation. Most such patients do not undergo subsequent cholecystectomy. The frequency of gallbladder stone and/or biliary symptom recurrence was studied in 63 patients who had undergone successful cholecystolithotomy. Follow-up examinations in 48 of these patients, performed at a mean of 18 +/- 12 months after surgery, showed recurrence of gallstones in 13 patients (27%). This included 12 of 38 patients who had follow-up sonograms and one of two cadavers that underwent autopsy. None of eight patients who had a subsequent cholecystectomy had recurrent stones. Two of 17 patients studied within 1 year of cholecystolithotomy had recurrent calculi, as did six of 21 patients studied at 1-2 years, four of five patients studied at 2-3 years, and one of five patients studied at 3-4 years. Biliary symptoms were assessed in 46 of the 48 patients who had follow-up examinations (two patients died) and in the 15 other patients who had undergone successful cholecystolithotomy. Recurrent or residual symptoms were present in seven (11%) of 61 patients, including three of the 13 patients with recurrent calculi. Six of these seven patients underwent further hospital treatment. These results confirm the anticipated high frequency of stone recurrence after cholecystolithotomy. However, because most patients with recurrent stones were asymptomatic, routine interval cholecystectomy may not be necessary.

Acute Disease↗