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Biomedical subjects

S Y Yang

Publications and source records attributed to S Y Yang.

At least 163 records · Page 9Linked to original sources
PubMed1990

[Clinical significance of changes in the serum level of endogenous digitalis-like factor in patients with chronic congestive heart failure].

Determination of serum endogenous digitalis-like factor (EDF) concentration was carried out in 52 patients with chronic congestive heart failure with radioimmunoassay. The results showed that concentration of serum EDF in patients with chronic congestive heart failure was significantly lower than that in normal subjects (P less than 0.001). The lowering of serum EDF concentration was significantly negatively correlated with the severity of heart failure, r = 0.6475, P less than 0.001. Age had no significant effect on serum EDF concentration (P greater than 0.05). Serum EDF concentration rose after the heart failure was treated, but was still lower than that in normal subjects (P less than 0.01). Serum EDF concentration in patients with coronary heart disease was the lowest and in patients with hypertension the highest.

Adult↗
PubMed1990

Isolation and partial characterization of Bermuda grass-pollen allergen: BG-60b.

Our earlier studies have shown that the pollen of Bermuda grass (Cynodon dactylon)-pollen contain at least 12 IgE-binding proteins which can be analyzed by the immunoblot technique. One of the highly active components was found to be a basic protein with a molecular weight of 60,000 daltons, designated as BG-60. This component was showed to consist of a group of proteins. One of them, BG-60a (pI 9.7), has been isolated and characterized. In this study, we have further isolated and characterized the second component of the antigen, designated as BG-60b. Its purity was demonstrated by gel electrophoresis experiment and antigen-antibody precipitation studies. The antigen is of glycoprotein nature with a pI of 10.0. It exhibits IgE-binding activity and shows cross-reactivity to antigen BG-60a in double diffusion. Its chemical and physical properties are similar to antigen BG-60a.

Allergens↗
PubMed1990

[A clinical study on 65 cases with tracheobronchial tuberculosis].

We recently diagnosed 65 cases with tracheobronchial tuberculosis using fiberbronchoscope. All the patients presented TB symptoms and were smear positive, some of them had been misdiagnosed for chronic bronchitis or lung cancer. Among them, 16 cases were simple tracheobronchial tuberculosis (24.6%) without TB lesions in the lungs. The results show that fiberbronchoscopic examination is a good method to diagnose tracheobronchial tuberculosis and distinguish lung cancer by direct observation of tracheobronchial lostons or brush biopsy for TB.

Adult↗
PubMed1989

Molecular analysis of the serologically defined HLA-Aw19 antigens. A genetically distinct family of HLA-A antigens comprising A29, A31, A32, and Aw33, but probably not A30.

The HLA-Aw19 complex consists of a number of serologically cross-reactive Ag (i.e., A29, A30, A31, A32, and Aw33) which exhibit an epitope shared by HLA-B and -C proteins. To investigate the structural basis for these serologic cross-reactivities, we have cloned and determined the nucleotide sequences for A30, A31, and Aw33, and compared the predicted amino acid sequences with those already available for A29, A32, and other class I allelic products. All alleles of the Aw19 group contained A-locus-specific sequences, exhibiting "A-ness." The structural similarities between Aw19 polypeptides were found in the alpha 1 and alpha 2 domains, where shared amino acid residues were identified that correlated with observed serological reactivity patterns. Seven Aw19-specific nucleotides were found. Two of these were silent substitutions, but the remaining five resulted in Aw19-specific amino acid residues. Each of the HLA-A alleles can be classified into one of the five serologically cross-reacting groups. In the Aw19 group, the alleles A29, A31, A32, and Aw33 are closely related serologically as well as genetically whereas A30 probably belongs to the A1/A3/A11 group. The similarity between A30 and the other Aw19 alleles may have resulted from two independent gene conversions affecting exons 2 and 3. Additional mutations or gene conversion-like events in A30 were also noted. It is postulated that gene conversions have played a significant role in the divergence of the Aw19 alleles. However, each serologically cross-reactive Aw19 allotype appears to have arisen directly from a common ancestral allele. A30 was the only exception, and this allele may represent an unusual allotype, which is subject to a high rate of genetic changes, as is seen in the H-2Kb gene of the mouse.

Alleles↗
PubMed1989

Graft failure after T-cell-depleted human leukocyte antigen identical marrow transplants for leukemia: I. Analysis of risk factors and results of secondary transplants.

Risk factors for graft failure were analyzed in 122 recipients of an allogeneic T-cell-depleted human leukocyte antigen (HLA)-identical sibling marrow transplant as treatment for leukemia. In each case pretransplant immunosuppression included 1,375 to 1,500 cGy hyperfractionated total body irradiation and cyclophosphamide (60 mg/kg/d x 2). No patient received immunosuppression prosttransplant for graft-versus-host disease (GVHD) prophylaxis. Nineteen patients in this group experienced graft failure. The major factors associated with graft failure were transplants from male donors and the age of the patient (or donor). Among male recipients of male donor-derived grafts a low dose per kilogram of nucleated cells, progenitor cells (colony forming unit-GM) and T cells was also associated with graft failure. Additional irradiation to 1,500 cGy, high dose corticosteroids posttransplant, and additional peripheral blood donor T cells did not decrease the incidence of graft failure. In addition, type of leukemia, time from diagnosis to transplant, an intact spleen, or the presence of antidonor leukocyte antibodies did not correlate with graft failure. To ensure engraftment of secondary transplants, further immunosuppression was necessary but was poorly tolerated. However, engraftment and survival could be achieved with an immunosuppressive regimen in which antithymocyte globulin and high dose methylprednisolone were administered both before and after infusions of secondary partially T-cell-depleted marrow grafts.

Age Factors↗
PubMed1989

Isolation and expression of a cDNA clone encoding HLA-Cw6: unique characteristics of HLA-C encoded gene products.

The HLA-C encoded gene products display several characteristics which distinguish them from HLA-A and -B. The HLA-C antigens are poorly expressed on the cell surface, they display multiple proteins with different isoelectric points, and alloimmunization to HLA-C antigens is less common. To investigate whether the multiple products result from differential splicing of HLA-C gene transcripts, we have isolated a full-length cDNA clone encoding the Cw6 antigen. Class I antigens produced by the cDNA clone in transfected cells were of the same relative mass as those observed in the parental cells when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Isoelectric focusing (IEF) gel analysis of the cDNA translated products in transfectants revealed multiple IEF bands. All IEF bands detected in the transfectants were also found in the parental cells, indicating that the multiplicity of the C-locus products was not due to differential splicing of HLA-C gene transcripts, but was probably due to post-translational modification. Comparison of the sequences of C-locus alleles with those of A and B alleles did not show any apparent sequences which would generate multiple IEF bands. Comparison of the coding regions for seven HLA-C alleles and one HLA-C-related class I gene with available data for 15 HLA-A and 20 HLA-B alleles demonstrated several unique features for the HLA-C locus. Six sites in the extra cellular domains, three in a1 and three in a3, were unique. While the cytoplasmic (CP) domain of HLA-A and -B are almost identical, the CP of HLA-C alleles is unique. Similar unique features of HLA-C are also observed in the transmembrane domain, resulting in locus-specific residues between positions 295 and 300. The present study has ruled out differential mRNA splicing as a mechanism for the multiplicity of Cw6 antigens and demonstrated unique HLA-C locus sequences.

Amino Acid Sequence↗
PubMed1989

Molecular mapping of a new public HLA class I epitope shared by all HLA-B and HLA-C antigens and defined by a monoclonal antibody.

It has previously been shown that a mouse monoclonal antibody, designated 4E, reacts with an epitope common to all HLA-B and -C antigens and those of the HLA-Aw19 cross-reactive group, namely, HLA-A29, -A30, -A31, -A32, -Aw33, and -Aw74. In order to pinpoint the amino acid residues which comprise the public specificity recognized by 4E, and HLA-A29 cDNA clone was isolated and its predicted amino acid sequence compared with those of other cloned HLA class I genes. The isolated HLA-A29 cDNA corresponded to the rarer of the two A29 variant alleles, A29.1. Two amino acid residues of HLA-A29.1, gln-144 and arg-151, were found in all 24 HLA-B and HLA-C alleles examined but were present in only one of 15 HLA-A alleles for which sequence data are available. Importantly, this exceptional allele was HLA-A32, another member of the HLA-Aw19 cross-reactive group. Gln-144 and arg-151 should be capable of jointly contributing to the binding site for 4E, as they are situated in successive alpha-helical subregions and are predicted to be juxtaposed in the three-dimensional HLA molecule. Four other residues in the first or second external domains of HLA-A29.1 (thr-9, leu-62, gln-63, and his-102) were unique among the HLA-A alleles, but none of these was found in corresponding positions of HLA-B of -C alleles and thus failed to correlate with presence or absence of the 4E determinant. These observations are consistent with the notion that gln-144 and arg-151 define a determinant common to HLA-B, HLA-C, and the HLA-Aw19 cross-reactive group and the binding site of the monoclonal antibody 4E.

Amino Acid Sequence↗
PubMed1989

Assay of L-3-hydroxyacyl-coenzyme A dehydrogenase with substrates of different chain lengths.

A method for assaying L-3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) which permits rate measurements with L-3-hydroxyacyl-CoA substrates of various chain lengths at physiological pH is described. The method is based on a coupled assay system in which 3-ketoacyl-CoA compounds formed by the dehydrogenase are cleaved by 3-ketoacyl-CoA thiolase (EC 2.3.1.16) in the presence of CoASH. The advantages of this assay method are its irreversibility and elimination of product inhibition. The assay procedure was used to determine the kinetic parameters (Km, Vmax) of pig heart L-3-hydroxyacyl-CoA dehydrogenase with several substrates of various chain lengths. The data obtained show the enzyme to be most active with medium-chain substrates whereas Km values for medium-chain and long-chain substrates are almost equal but much lower than those previously reported.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1989

Brain abscess associated with congenital heart disease.

Between 1952 and 1985, 25 cases of brain abscess with congenital heart disease were treated at the Department of Neurosurgery, Tianjin Medical College Hospital. Patients' ages ranged from 5 to 38 years. The most common form of congenital heart disease was tetralogy of Fallot, occurring in 13 cases. The abscesses were located in the parietal, frontal, and temporal lobes. The pus from the abscesses was sterile in 13 of 19 cases. In the rest, Streptococcus was the predominant organism. Twenty-three cases were treated by aspiration of the abscess through a burr hole. In two cases, initial aspiration was followed by excision of the abscess. The mortality rate of the whole group was 32%. The etiology of brain abscess in patients with congenital heart disease is discussed.

Adolescent↗
PubMed1989

[Experimental studies of hyperlipidemia in rats and mice given a hyperlipidemic diet].

Hyperlipidemia in rats and mice was induced by hyperlipidemic diet containing 1.5% cholesterol, 0.25% cholic acid, 7.5% lard and 90.75% essential diet. After feeding for 7 days, the serum cholesterol levels in the experimental group are about 5 times higher than that in the control group. It appears that there exist similarities between rats and mice and that these models may be used for screening tests of hypolipidemic drugs.

Animals↗
PubMed1989

A human-human hybridoma which produces antibodies to polioviruses.

A human-human hybridoma which produced antibodies to Sabin strain poliovirus types 3 and 2 was established. This hybridoma was constructed by fusing a HAT-sensitive variant of a human lymphoblastoid subline R4-4-6 with peripheral blood lymphocytes of a donor who had been previously immunized with poliovirus Sabin vaccines and had shown high titer of neutralizing antibodies against these viruses. This hybridoma had been cultured for more than one year and the neutralizing activities of the culture supernatants against poliovirus type 3 could still be detected. Cross neutralization with poliovirus type 2 was also observed. Karyotypic analyses of this hybrid showed that the chromosome numbers were distributed mainly between 80 and 100. Dot immunobinding assays also confirmed the reactivities of this hybridoma supernatants with poliovirus type 3 and, slightly, with type 2.

Antibodies, Monoclonal↗
PubMed1989

[Pharmacologic study of Curculigo orchioides Gaertn].

The experiments showed that ethanolic extract of Curculigo orchioides had adaptive effects, such as enhancing tolerance towards high temperature and hypoxia. It also had sedative, anticonvulsant and androgen-like effect. Besides, it increased the immunological activity of mice.

Adaptation, Physiological↗
PubMed1989

[Pregnancy and embryotoxicity of Rhizoma pinelliae in rats].

This experiment was conducted with sexually mature, virgin female rats. The body weight of the female rats was 230-350 g, that of male rats was 300-400 g. The female and male rats were mated overnight (the ratio was 3:1), the pregnant rats were divided into 7 groups. All drugs were given p.o. from the 6th to the 15th days of gestation. Pregnant rats were weighted on the 0th, 6th, 10th, 13th and 16th days of gestation. Vaginal bleeding of pregnant rats was examined on the 8th, 10th, 12th, 14th and 16th days of gestation. The rats were killed on the 20th day of gestation so as to count the number of implantation, dead and living fetuses. The living fetuses of rats were removes, weighted and inspected for gross abnormalities; the internal and skeletal malformations of live fetuses were examined. The following results were obtained: 9 g/kg dose of the crude Rhizoma Pinelliae powder was found to have the action in increasing the number of pregnant individuals with vaginal bleeding and dead embryo significantly. Comparing with the control, 9 g/kg dose of the powder of processed Rhizoma Pinelliae did not show any toxicity. But 30 g/kg dose of the decoction of processed or crude Rhizoma Pinelliae was found to increase the number of pregnant individuals with vaginal bleeding and dead embryo significantly.

Abnormalities, Drug-Induced↗
PubMed1988

A novel activation pathway for mature thymocytes. Costimulation of CD2 (T,p50) and CD28 (T,p44) induces autocrine interleukin 2/interleukin 2 receptor-mediated cell proliferation.

Prior studies have shown that thymocytes, unlike peripheral T cells, do not proliferate in response to mitogenic combinations of anti-CD2 mAbs. The present study demonstrated that stimulation by a mitogenic anti-CD2 combination (9-1 plus 9.6) with anti-CD28 induced vigorous thymocyte proliferation in the absence of exogenous IL-2. This thymocyte proliferation was IL-2 dependent as shown by the complete inhibition using anti-IL-2-R mAbs. Induction of IL-2-R transcripts was detected in thymocytes stimulated by the anti-CD2 antibody combination alone or the anti-CD2 combination plus anti-CD28 antibody. However, induction of IL-2 transcripts was observed only in thymocytes triggered jointly by the anti-CD2 combination plus anti-CD28 antibodies. The double-negative (CD4-8-) or CD1+ thymocytes isolated by sorting or by panning were unresponsive to CD2/CD28 triggering. The same mitogenic signal could induce vigorous proliferation of thymocytes with a mature phenotype, i.e., CD3+CD4+ or CD3+CD8+ thymocytes. Immunofluorescence studies demonstrated that the majority of CD3+ thymocytes were CD28+, and most of the CD28+ cells were located in the medullary compartment of thymus. These results indicated that the T cell lineage surface molecules CD28 and CD2 are involved in the regulation of expansion and further differentiation of mature thymocytes.

Antibodies, Monoclonal↗
PubMed1988

Enhancing effect of anti-HLA class I monoclonal antibodies on T cell proliferation induced via CD2 molecule.

The mAb 131 to a determinant preferentially expressed on the gene products of the HLA-A locus, the mAb Q6/64 and 4E to determinants preferentially expressed on the gene products of the HLA-B locus, the anti-HLA-A2,A28 mAb CR11-351, HO-2, HO-3, HO-4, and KS1, and the anti-HLA-B7 cross-reacting group mAb KS4 enhanced proliferation of T cells in most, if not all, the PBMC preparations stimulated with the anti-CD2 mAb 9-1 + 9.6. The mAb CR10-215, W6/32, and 6/31 to distinct monomorphic determinants of HLA class I antigens enhanced CD2-induced T cell proliferation in at most 30% of the PBMC preparations tested. The anti human beta 2-microglobulin (beta 2-mu) mAb NAMB-1 displayed no detectable effect on the proliferation of T cells stimulated with the mAb 9-1 + 9.6. The enhancing effect of anti-HLA class I mAb is specific, is dose dependent, is not abrogated by the addition of exogenous IL-1 and IL-2 to the cultures, and reflects the interaction of anti-HLA class I mAb with T cells. Enhancement of CD2 mediated proliferation of T cells is not a unique property of anti-HLA class I mAb, since the anti-HLA class II mAb Q5/6 and Q5/13 also had a similar effect. Analysis of the kinetics of the enhancing effect of anti-HLA class I mAb suggests that they modulate an early event of T cell activation and may affect the interaction of T cells with mAb 9-1. Phenotyping of T lymphocytes activated by mAb 9-1 + 9.6 in the presence of anti-HLA class I mAb suggests that the enhancing effect of anti-HLA class I mAb may reflect the recruitment of a higher percentage of T cells. The present study has shown for the first time that certain, but not all, the determinants of the HLA class I molecular complex are involved in the proliferation of T cells stimulated with the anti-CD2 mAb 9-1 + 9.6. Furthermore, the inhibitory effect of mAb CR11-351, KS1, Q6/64, and W6/32 on the proliferation of T cells stimulated with mAb OKT3 or with mAb BMA 031 indicates that the same determinants of HLA class I antigens play a differential regulatory role in T cell proliferation induced via the CD2 and CD3 pathway.

Adjuvants, Immunologic↗
PubMed1988

Isolation and nucleotide sequence of a cDNA clone encoding a novel HLA class I gene.

A cDNA clone, designated JTW15, has been isolated and found to encode a novel, divergent class I HLA gene transcript. The clone was identified by its ability to hybridize with a pan-HLA class I nucleotide probe while failing to bind probes specific for the 3' untranslated exons of the HLA-A, -B, and -C genes. JTW15, 1665 nucleotides in length, represents a full length copy of an approximately 1.7-kb mRNA detected in Northern blot analyses. Comparison of the derived amino acid sequence with those of other HLA class I proteins showed JTW15 to be the most divergent HLA class I gene identified so far, the level of sequence homology being lowest for the alpha 1 and alpha 2 domains. The JTW15 gene transcript was found in a broad variety of cell types and was inducible in cells treated with IFN-gamma. JTW15 is the first isolated full length cDNA clone defining a non-HLA-ABC class I gene.

Amino Acid Sequence↗
PubMed1988

Differential in vitro activation of CD8-CD4+ and CD4-CD8+ T lymphocytes by combinations of anti-CD2 and anti-CD3 antibodies.

Purified peripheral blood T lymphocytes and the CD8-CD4+ and CD4-CD8+ T cell subsets, exhaustively depleted of APC have been studied for their capacity to respond to mAb directed against the CD3-Ti Ag-specific TCR complex and against the CD2 SRBCR. It is demonstrated that high affinity IL-2R can be readily induced by either anti-CD3 and/or anti-CD2 stimulation. However, IL-2 production can be observed only in the CD4+CD8- T cell subset. These results clearly contrast data obtained with purified CD4-CD8+ T cells, which are able to proliferate when the CD3-Ti complex is activated in the presence of APC. The data presented in the present study demonstrate that a simplified model for T cell activation and clonal expansion of the two major T cell subsets involve only the CD3-Ti complex and the CD2 Ag. Under conditions where the activation signals for the T cells are restricted only to the activation of CD3-Ti and CD2, the CD4+CD8- T cells respond with IL-2 production and expression of high affinity IL-2R, whereas the CD4-CD8+ T cell subset depends on exogenous IL-2 provided by the CD4+CD8- cells. These data do not, however, exclude an involvement of other cell-surface signals for regulation and control of T cell activation and T cell effector functions.

Antibodies, Monoclonal↗