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Biomedical subjects

H Y Luo

Publications and source records attributed to H Y Luo.

At least 37 records · Page 2Linked to original sources
PubMed1991

In vitro IgE production by interleukin 4-stimulated human peripheral blood mononuclear cells is suppressed by rapamycin.

Rapamycin (RAPA) is a new immunosuppressant which is 50-fold to 100-fold more potent than cyclosporin A (CyA) in inhibiting cellular immune responses and allograft rejection in animal models of organ transplantation. The drug's effect on in vitro IgE synthesis by interleukin (IL)4-stimulated human peripheral blood mononuclear cells was examined and compared with CyA's effect in this study. RAPA was found to be about 100-fold more potent than CyA in inhibiting IgE synthesis. Its inhibitory effect on IgE production was significant if it was added to the culture before Day 6 of a 14-day culture. The suppression was accompanied by the inhibitory effect on cell proliferation and on IgE-binding factor (IgE-BF) production. IL2 was able to partially reverse CyA- but not RAPA-induced inhibition of IgE production. Commercial B cell growth factor (cBCGF) was not able to reverse either RAPA- or CyA-induced suppression of IgE synthesis. The strong inhibitory effect of RAPA in IgE synthesis may be useful in certain clinical applications where overproduction of pathogenic IgE is a key issue. RAPA can also be used as a tool to dissect the regulation of IgE production.

Cell Division↗
PubMed1991

Antiproliferative effect of interleukin-4 in B chronic lymphocytic leukemia.

Recombinant interleukin-4 (IL-4) profoundly inhibits the proliferative response of chronic lymphocytic leukemic B cells (B-CLLs) to recombinant interleukin-2 (IL-2). In the present study, we confirmed and extended these data by showing that IL-4 strongly suppresses the [3H]thymidine incorporation by B-CLLs stimulated by recombinant tumor necrosis factor alpha, recombinant interferon alpha, IL-2, and low molecular weight B cell growth factor in the absence of costimulant. Recombinant interleukin-4 inhibits spontaneous DNA synthesis suggesting that it also interferes with the autocrine proliferation of these cells. Kinetic studies indicate that IL-4 suppresses rather than shifts the peak of cytokine-induced DNA synthesis. Moreover, IL-4 blocks the progression of B-CLLs in or into G1 stage of the cell cycle as shown by the inhibition of cytokine-induced [3H]uridine incorporation. Finally, IL-4 pretreatment of B-CLLs prevents their subsequent proliferative response to the above cytokines, indicating that IL-4 confers to the B-CLLs a state of resistance to numerous stimulatory cytokines. The antiproliferative effects of IL-4 suggest that this lymphokine may have important therapeutic implications for the B-CLL patients.

Cell Cycle↗
PubMed1991

[Central norepinephrine and angiotensin II contents in the brain regions of spontaneously hypertensive rats (SHR) and the interaction between them].

The norepinephrine (NE) and angiotensin II (A II) contents in the brain regions of SHR and WKY (Wistar Kyoto) rats at different ages were determined by fluorospectrophotometry and radioimmunoassay. The systolic blood pressure (SBP) of the rats was measured indirectly with a tail cuff technique in conscious state. The results were as follows: There was no significant difference in the central A II and NE contents between SHR and WKY rats at 8-week age. Since 12th week age the SBP of SHR has increased gradually, up to 16th to 20th week and then maintained steady level. Whereas there was no significant change of SBP in WKY rats in the same span of age. In the early and late states of hypertension the A II contents in the medulla oblongata, pons, hypothalamus and nucleus caudatus of SHR were markedly higher than those of the age-matched WKY rats. But the change of NE content of SHR in the early stage showed a different picture as compared with that of WKY rats, i.e., NE decreased in medulla oblongata and anterior hypothalamus but increased in pons, posterior hypothalamus and nucleus caudatus. However, in the late stage there was no such significant difference between SHR and WKY rats. Consequently, it is suggested that the central A II and NE participated in the development of hypertension of SHR, and that the maintenance of hypertension is mainly dependent upon the increased A II content. Microinjection of captopril or 6-OHDA in the lateral cerebroventricle of SHR elicited a decrease of BP and reduction of both A II and NE contents in the medulla and hypothalamus.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1990

1,25(OH)2 vitamin D3 inhibits the CD23 gene expression by human peripheral blood monocytes.

A biologically active form of vitamin D, 1,25(OH)2D3, and a leukocyte surface molecule, CD23, play important roles in immune regulation. The effect of 1,25(OH)2D3 on the CD23 gene expression was examined in this study. The results show that 1,25(OH)2D3 suppresses spontaneous and IL-4-stimulated CD23 synthesis by peripheral blood monocytes. The inhibition occurs at both the protein and mRNA levels. However, 1,25(OH)2D3 has no inhibitory effect on CD23 production by either resting or activated tonsillar B cells. Our results suggest a possible role of 1,25(OH)2D3 in the regulation of certain immune and inflammatory responses via its effect on CD23 production.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1989

Analysis of 4628 cases in the genetic counselling clinic of PUMC Hospital.

An analysis of 4628 cases in the genetic counseling clinic of PUMC Hospital is reported. Althogether 966 cases (20.87%) were diagnosed as having genetic diseases, among whom were 436 cases (45.13%) with chromosome aberrations, 161 (16.67%) with inherited metabolic diseases, 111 (11.49%) with constitutional bone diseases, 103 (10.66%) with various kinds of genetic neuromuscular diseases, 109 (11.28%) with different dysmorphic syndromes, and 46 (4.76%) with different kinds of genetic dermatoses and oculopathies. 973 cases (21.02%) were suspected to suffer from some form of genetic disease, but this could not be proved due to a lack of specific diagnostic methods. 2689 cases (58.10%) were found to be unaffected by inherited diseases. Some of the experiences gained and the key role of genetic counselling in family planning are briefly discussed.

Adolescent↗
PubMed1988

Potential application of a new screening test for alpha-thalassemia-1 carriers.

A murine hybridoma cell line secreting monoclonal anti-human embryonic zeta-globin chain antibody has been established. Using this monoclonal antibody, a slot blot immunobinding assay for the detection of zeta-globin chains in adult hemolysates has been developed. This simple test can identify individuals who are alpha-thalassemia-1 carriers due to the (-SEA/) deletion. It is proposed that this test should be made generally available in Southeast Asia and Southern China, in order to identify couples who are at risk of begetting fetuses afflicted with homozygous alpha-thalassemia.

Animals↗
PubMed1988

An immunoassay to detect human embryonic epsilon globin chains by a murine monoclonal antibody.

Human embryonic epsilon globin chains were isolated from lysates of cultured human leukemic K562 cells induced with hemin. Mice were immunized with epsilon globin chains, and a murine hybridoma cell line was established that secreted monoclonal anti-epsilon globin antibody. A sensitive and specific slot blot immunoassay for epsilon globin chains has been developed. epsilon Globin chains were shown to be present in hemolysates from fetuses of 20 weeks' gestation but were not detected in normal cord blood hemolysates. This immunoassay is useful for the study of epsilon globin ontogeny during embryonic and fetal development as well as for searching for inappropriate epsilon globin chain expression in hematologic disorders resulting from genetic abnormalities or neoplastic processes.

Animals↗
PubMed1988

A novel monoclonal antibody based diagnostic test for alpha-thalassemia-1 carriers due to the (-SEA/) deletion.

The presence of minute amounts of embryonic zeta-globin chains in adult hemolysates is a marker for carriers of alpha-thalassemia-1 resulting from (--SEA/) deletion. Recently, we developed a murine monoclonal antihuman embryonic zeta-globin chain antibody, 8E8. By using this antibody, we have now established a slot-blot immunobinding assay for the rapid detection of zeta-globin chains in adult hemolysates. zeta-globin chains were found to be present in 30 blood samples obtained from individuals who were carriers of alpha-thalassemia-1. In another 30 blood samples from individuals who were not carriers of the (--SEA/) deletion, zeta-globin chains were not detected. This simple diagnostic test can be used in appropriate populations to identify those couples at risk of conceiving fetuses afflicted with the Hb Bart's hydrops fetalis syndrome due to homozygous alpha-thalassemia.

Antibodies, Monoclonal↗