Biomedical subjects

K C Chadha

Publications and source records attributed to K C Chadha.

58 records · Page 4Linked to original sources

PubMedDate not supplied

Segregation of normal and pathological human red blood cells, lymphocytes and fibroblasts by immobilized metal-ion affinity partitioning.

Immobilized metal-ion affinity partitioning (IMAP) is shown to be useful as a preliminary screening test and for the separation of different cell populations based upon recognition of the differences in the proteins on cell surfaces. The feasibility of using IMAP to segregate a spectrum of normal human cells (red blood cells, lymphocytes and fibroblasts) from their counterpart pathological cells has been demonstrated. A clear segregation between normal and sickle-cell anemia red blood cells (RBC), or malaria (Plasmodium vivax) infected RBCs was obtained. Further, the partition differences were found to depend on the nature and the concentrations of metal used. Cells from breast cancer and those from the lung adenocarcinoma showed differences in their partition pattern as compared to normal fibroblasts when PEG-IDA-M(II) was added to the phase system. Maximum differences between the three cell populations were observed in the presence of 10% PEG-IDA-Ni(II). Normal lymphocytes and Burkitt's lymphoma cells (Raji and Namalwa cell lines) were shown to partition differently in the presence of PEG-IDA-M(II) in the phase system. Normal lymphocytes could be distinguished from the Burkitt's lymphoma cell lines in all three phases (top, interface and bottom), in the presence of 10% PEG-IDA-Ni(II) in the system. These differences in the partition behavior could mainly be attributed to the density, surface exposure and micro-environment of histidine residues of cell membrane-associated proteins. These data, along with those obtained for normal and pathological human cells show that IMAP could be a simple and versatile tool for the segregation and study of cells.

Adenocarcinoma↗

PubMedDate not supplied

Effect of alcohol on spleen cells and their functions in C57BL/6 mice.

Spleen cells from C57BL/6 mice maintained on alcohol containing liquid diet for two weeks were evaluated for different immune functions. On an average, 22% fewer spleen cells were recovered from alcohol-fed mice when compared to cells from control animals. In alcohol-fed mice, the relative frequency of B cells increased, whereas total T cells including CD4+ cells decreased significantly. Alcoholic mice, when challenged with poly(rI) poly(rC), produced significantly less interferon than control mice. In vitro production of interferon alpha and gamma by the spleen cells of alcoholic mice was reduced by 67-90%. No significant differences were seen in the level of natural killer cell activity in spleen cells of control and alcoholic mice. These results suggest that chronic alcohol intake can result in not only changes in the number of immune cells, but more importantly affect their biological functions such as their ability to produce interferons.

Alcohol Drinking↗

PubMedDate not supplied

Mild hyperthermia modulates biological activities of interferons.

A significant enhancement of antiviral activity of human IFN-alpha, -beta and -gamma and murine IFN-gamma is observed when cells are treated with mild hyperthermia (39 degrees C) during antiviral assays. Treatment of primary human fibroblast cells with mild hyperthermia for 4 and 24 hours prior to interferon antiviral assays (pre-assay hyperthermia) further enhances interferon antiviral activity. An enhancement of interferon induced enzyme, 2,5-oligoadenylate synthetase, is also observed in cells treated with interferon and mild hyperthermia. This increase in enzyme activity is, in part, responsible for the observed increase in interferon antiviral activity with hyperthermia. Besides antiviral activity, mild hyperthermia also increases interferon antiproliferative activity on different tumour cells beyond its effect at normal physiological temperatures. On the other hand, mild hyperthermia decreases human interferon production in both human and murine cells when challenged with a viral or non-viral inducer. Also, mild hyperthermia suppresses interferon-mediated enhancement of natural killer (NK) cell activity in human and murine cells. The findings demonstrate that, although mild hyperthermia has suppressive effects upon interferon production and NK cell activity, it significantly increases both antiviral and antiproliferative activities of all three human interferons. These observations have direct bearing upon clinical utilization of exogenously administered interferons to late stage cancer patients who for the most part have a weaker immune system. In these patients, the antiviral and antiproliferative efficacies of administered interferon can be enhanced by combining interferon and hyperthermia.

2',5'-Oligoadenylate Synthetase↗

PubMedDate not supplied

Interferon inhibitor in the blood of patients with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) patients at advanced stages of the disease have an interferon inhibitor in the blood circulation. This inhibitor can block antiviral activity of all three types of human interferons and can significantly reduce the synthesis of interferon alpha by the treated lymphocytes obtained from normal healthy individuals. Available evidence suggests that inhibitor activity is neither because of the antibody to interferon nor due to high level of protease-like activity in the plasma. The inhibitor has also been shown to be effective in eliminating the interferon-mediated enhancement of natural killer cell activity. Interferon inhibitory activity was not detected in any of the sera taken from normal healthy individuals. Identification and characterization of interferon inhibitor has direct bearing upon effective utilization of interferons in the clinic.

Animals↗