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Biomedical subjects

D S Chi

Publications and source records attributed to D S Chi.

At least 73 records · Page 4Linked to original sources
PubMed1982

Effect of histoincompatibility on migration of labeled bursa cells in the chicken.

A comparison was made of the localization of i.v. injected 3H-adenosine-labeled bursa cells in gamma-irradiated B-identical and B-different recipient chickens. There was no difference in the localization in nonlymphoid organs or in bursa and thymus, but the spleen showed more radioactivity at 24 hr after injection in B-identical than in B-different recipients. This difference was more reproducible in 3 to 4 week or older than in 7- to 10-day-old recipients. Histologically, the greatest difference in the older recipients was seen in the number of labeled cells localizing in germinal centers of spleen. Thymectomy or bursectomy of recipients did not appear to affect the bursa cell localization. syngeneity at the major histocompatibility B locus between donor and recipients appeared sufficient to obtain maximal spleen localization of donor bursa cells.

Agammaglobulinemia↗
PubMed1980

Antigen-induced helper and suppressor T cells in normal and agammaglobulinemic chickens.

Spleen cells from chickens injected with sheep erythrocytes (SE) intravenously 2 to 14 days prior to culture were found to give faster and higher plaque-forming cell responses upon addition of antigen on day 2 rather than on day 0 of culture. Cell mixture experiments showed that this was due to the induction of suppressor T cells upon re-exposure to SE on day 0 of culture. Spleen cells taken on days 2 or 14, but not between days 4 and 7 after priming to SE were sensitive to suppression. The suppressor cells were resistant to gamma irradiation (1000 rd) and to mitomycin C, but were apparently lost after 2 days of culture in the absence of antigen. Pokeweed mitogen addition on day 0 of culture also induced suppressor cells, both in SE immune and in normal spleen. Similar suppressor cells were induced in cultures of primed spleen cells taken from agammaglobulinemic chickens. The response to Brucella abortus in vitro was not affected by induction of suppression for the anti-SE response. Suppression could also be shown after transfer of cell mixtures to irradiated recipients. Helper cell activity for the anti-SE response could readily be shown, both in vivo and in vitro, in primed spleen cells precultured for 2 days in the absence of antigen, and was also resistant to 1000 rd gamma irradiation and to mitomycin C.

Agammaglobulinemia↗
PubMed1978

A simple method for the isolation of murine peripheral blood lymphocytes.

A simple, rapid and reproducible semi-microtechnique was developed for the isolation of murine peripheral blood lymphocytes. Murine peripheral blood was collected from brachial vessels and centrifuged through a Ficoll--Hypaque gradient in a microfuge tube yielding 1--1.5 X 10(6) lymphocytes per mouse.

Animals↗
PubMed1977

Relationship of surface immunoglobulin-bearing cells, plasma cells, and tumor development in anaplastic carcinoma-bearing A/J mice.

Since the humoral immune response has been shown to be associated with immunological enhancement of tumor growth, the study of surface immunoglobulin-bearing cells and plasma cell antigen (PCA)-bearing cells during neoplastic development may provide new approaches to the study of tumor immunology. Peripheral blood was collected every other day from normal and carcinoma-bearing mice. Lymphocytes obtained by Ficoll-Hypaque density centrifugation were assayed for immunoglobulin-bearing cells and PCA-bearing cells using either fluorescein-conjugated goat anti-mouse immunoglobulin or rabbit anti-mouse plasma cell serum and fluorescein-conjugated goat anti-rabbit immunoglobulin. A marked increase in immunoglobulin-bearing cells from tumor-bearing mice was observed by Day 6 and peaked at Day 10. An increase in PCA-bearing cells followed the immunoglobulin-bearing cells increas by 2 to 4 days. The immunoglobulin-bearing cells declined by Day 12, whereas PCA-bearing cells remained elevated through Day 20. Using rabbit anti-mouse plasma cell serum as an immunosuppressive agent, a 4-day prolongation of the mean survival time was observed in rabbit anti-mouse plasma cell serum-treated tumor-bearing mice. This suggests that tumor growth in this model may be related to an active humoral immune response and that suppression of the plasma cell population may prove to be beneficial in the treatment of certain tumors.

Animals↗
PubMed1976

Comparative sensitivity of two hemagglutination inhibition immunoassays for fibrinolytic degradation products in human serum.

A new modification of hemagglutination inhibition immunoassay for measuring fibrinogen/fibrin degradation products (FDP) using glutaraldehyde as a coupling reagent was introduced. This method was compared with the tanned-red-cell hemagglutination inhibition immunoassay (TRCHII). Sheep erythrocytes (SRBC) were sensitized with fragment D or E, respectively. The procedure of sensitizing SRBC is simple and can be achieved within 2 hrs. The sensitized SRBC stored at 4 degrees C for 6 months did not lose their activities. The sensitivities for assaying D and E relative FDP were 0.32 mug/ml, respectively, which were slightly better than those of TRCHII. This represents the first adaptation of glutaraldehyde erythrocyte hemagglutination inhibition immunoassay (GEHII) for the estimation of FDP employing either microtiter plate or test tube. The microtechnique and test tube method were found to be essentially equivalent. The FDP level in the sera of normal individuals and patients suspected of elevation of FDP were assayed by both TRCHII and GEHII. By linear least squares analysis, the results show a significant correlation between these two methods. These results indicate GEHII is a simple, rapid and sensitive immunoassay for FDP in human serum.

Erythrocytes↗
PubMed1975

Fibrinogen-fibrin degradation products: hemagglutination inhibition immunoassay in plasma.

Immunoassay for fibrinogen and/or fibrin degradation products (FDP) is generally in the clot and hence assay of serum may not reveal the true concentration of FDP in blood. We have developed a hemagglutination inhibition immunoassay for FDP in human plasma. D fragment appears to possess an antigenic determinant, called D-neoantigen, not found in native fibrinogen. Rabbit antiserum produced against D fragment was absorbed with immunosorbent columns coupled with fibrinogen and normal human serum, respectively, so that it contained only those antibodies directed against the neoantigenic determinant of D fragment. In this immunoassay, sheep erythrocytes (SRBC) were stabilized with glutaraldehyde and subsequently sensitized with D fragment by means of tannic acid. Hemagglutination of absorbed anti-D-neoantigen serum against SRBC sensitized with D fragment was titered to be 1:256. The hemagglutination was inhibited by D fragment but not by fibrinogen; the sensitivity of detecting D fragment was 8 mug/ml. Human plasma from normal subjects did not inhibit. This appears to be the first report of a hemagglutination inhibition immunoassay for FDP in plasma.

Animals↗
PubMedDate not supplied

Long-term experience in the surgical management of cancer of the uterine cervix.

Cancer of the uterine cervix is the seventh most common malignancy among women and the fifth most common cause of cancer mortality worldwide. In the United States, the use of the Papanicolaou (Pap) smear for screening has meant a significant decline in the incidence and mortality from cervical cancer over the past five decades. However, there are still approximately 12,800 new cases diagnosed per year in the U.S. and 4,800 deaths are estimated in 1999. Both surgery and radiation therapy have long-established roles in management. Surgery has the advantages of shorter treatment time, removal of the primary tumor, more limited tissue injury, and the potential to preserve ovarian function; radiation therapy has the capacity to treat tumor that involves the bladder and/or rectum while preserving their function. Therefore, the role of surgery is more suited to the management of early-stage disease and centrally located recurrences that occur after radiation therapy. Studies from our institution have played an integral role in the development of the modern surgical approach to cervical cancer. Reviews on early-stage disease helped define the role of conization and simple hysterectomy for microinvasive cervical cancer and identified patients who were at high risk for recurrence after radical hysterectomy. The classic work of Brunschwig has given gynecologic surgeons the ability to offer hope and life to select patients who previously could have expected only pain and death. Future investigation into the techniques of intra-operative radiation therapy may increase the pool of patients for whom surgically based salvage therapy may be offered.

Combined Modality Therapy↗
PubMedDate not supplied

Brain peptide reverses effect of morphine on human lymphocytes.

E-rosette formation by human lymphocytes incubated with sheep red blood cells (sRBC) is inhibited by morphine. We studied the ability of the opiate antagonists naloxone and Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) to block this action. Active E-rosette formation by lymphocytes incubated with morphine was reduced from the control of 35.7 +/- 1.7% to 23.7 +/- 1.5% (p less than 0.001). Similarly, total E-rosette formation was reduced by morphine from the control of 65.8 +/- 1.3% to 53.2 +/- 2.9% (p less than 0.001). These effects were blocked by co-incubation of the lymphocytes with either Tyr-MIF-1 or naloxone (p less than 0.05). Tyr-MIF-1 was active (p less than 0.05) at concentrations as dilute as 10(-13) M. These results indicate that the neuropeptide Tyr-MIF-1 exerts an antiopiate effect at the human T-lymphocyte.

Adult↗