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Biomedical subjects

H Pham

Publications and source records attributed to H Pham.

62 records · Page 4Linked to original sources
PubMed1986

Monoclonal antithyroglobulin antibodies derived from immunizations of mice with human eye muscle and thyroid membranes.

A mouse hybridoma clone secreting an immunoglobulin M monoclonal antibody (K-5-4), which reacted with human thyroglobulin (Tg), was obtained from spleen cells of mice immunized with crude membranes of human eye muscle tissues (Em). Its binding to Tg could be inhibited by another monoclonal anti-Tg (F1-11-1) derived from spleen cells of mice immunized with human thyroid cell membranes, but K-5-4 did not inhibit the binding of F1-11-1 to Tg. This finding suggests that K-5-4 may react with a site on the Tg molecule which is susceptible to conformational changes, such as that induced by binding of another anti-Tg antibody at another site on Tg. K-5-4 reacted with human, mouse, rat, guinea pig, bovine, and porcine Tg. Binding and immunohistological staining experiments failed to detect binding of K-5-4 to Em tissue. The very low frequency of one Tg-reacting hybridoma from 6 X 10(8) spleen cells fused after Em immunization contrasts with the relative ease with which monoclonal anti-Tgs were generated from spleen cells of mice immunized with crude human thyroid membranes. In the latter case, 1 anti-Tg hybridoma was generated for every 100,000 spleen cells fused, and an extensive library of monoclonal anti-Tgs was collected. Some of these antibodies were specific for human Tg only, while others cross-reacted with Tg of other animal species. None had the species reativity pattern of K-5-4. The anti-Tgs were used to affinity purify human Tg directly from supernatant of thyroid homogenate; the purified Tg was, in turn, used to affinity purify human polyclonal but monospecific anti-Tg directly from serum of patients in a simple and rapid procedure. We conclude that the monoclonal anti-Tgs are useful reagents in isolating and purifying Tg and anti-Tg.

Animals↗
PubMed1985

Helper and suppressor activities of lymphocyte subsets on antithyroglobulin production in vitro.

We studied the regulatory activities of T cells on specific antithyroglobulin (anti-Tg) and nonspecific immunoglobulin secretion in cultures of peripheral blood lymphocytes (PBL) of five patients with autoimmune thyroid diseases and high levels of serum anti-Tg. PBL were separated into a non-T population, including B-cells and monocytes, and a T-cell population by rosetting with sheep red cells. T-Cells were further separated into T helper (Th) and T suppressor (Ts) subsets by a panning technique using the monoclonal antibodies anti-Leu 3a and anti-Leu 2a, respectively. The three sets of cells, i.e. B, Th, and Ts, from patients and from normal individuals were cocultured in various combinations and stimulated with the polyclonal stimulant pokeweed mitogen. A sensitive plaque assay was used to enumerate cells producing anti-Tg and protein A-binding immunoglobulins. The PBL of both patients and normal individuals had Tg-specific suppressor cells. Ts-cells from patients in syngeneic or allogeneic combinations with B- and Th-cells at a ratio of 1:1:1 suppressed the pokeweed mitogen-induced anti-Tg response to 41 +/- 8% (+/-SE) and 50 +/- 20% of the control value, respectively, while Ts from normal individuals suppressed the response to 7 +/- 3% of the control value. The suppressive effect of the Ts-cells from patients and normal individuals on nonspecific immunoglobulin secretion was similar (reduced to 10-15% of control). Thus, there appeared to be a deficiency in Tg-specific suppressor activity in PBL of patients. On the other hand, Th-cells from patients (syngeneic or allogeneic) cocultured with patient B-cells produced a greater anti-Tg response than Th-cells from normal individuals. The helper activities of Th-cells of patients and normal individuals on nonspecific immunoglobulin secretion were similar. Thus, there appeared to be an increase in Tg-specific helper activity in PBL of patients.

Autoantibodies↗
PubMed1984

Five-year follow-up of Vietnamese refugee children in the United States.

The purpose of this study was to investigate the present physical, mental, and psycho-social health of Vietnamese refugee children. Questionnaires were sent or given to adoptive families, foster families, and Vietnamese children living in the United States with their family units. Otitis media, respiratory ailments, and varicella constituted a large number of their initial medical problems. Severe nightmares and temper tantrums occurred frequently during their first year. It was found that the children's health and emotional problems improved markedly after the first year. Despite stormy pasts, present social and school problems are minimal, and some children appear to be high achievers. Most of the Vietnamese children, especially those who were adopted, are doing much better than we anticipated. Advance preparation and guidance given by the involved agencies appear to be of significance in achieving these excellent results.

Adaptation, Psychological↗