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Biomedical subjects

J Lin

Publications and source records attributed to J Lin.

At least 109 records · Page 6Linked to original sources
PubMed1994

Viremia and serological responses in adult chickens infected with western equine encephalomyelitis and St. Louis encephalitis viruses.

Adult hens, similar to those used for arbovirus surveillance, were experimentally infected with western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses to describe the viremia response, to compare serological testing methods, and to evaluate a new method of collecting whole blood onto filter paper strips from lancet pricks of the chicken comb. Young (19 weeks), but not old (38 weeks), hens developed a low-titer, transient viremia for a 1-day period. Immunoglobulin G (IgG) was detected by days 10 and 14 after infection with WEE and SLE viruses, respectively, by indirect fluorescent antibody tests, hemagglutination inhibition tests, and plaque reduction neutralization tests on sera and in direct enzyme immunoassays (EIA) on both sera and eluates from filter paper samples. Immunoglobulin M (IgM) was first detected in sera 2 and 3 days before IgG, respectively, but IgM could not be detected reliably in eluates from dried blood. Sera and dried blood samples collected from naturally infected sentinel chickens gave comparable results when tested by an EIA for IgG.

Animals↗
PubMed1994

Effects of beta-endorphin on phytohemagglutinin-induced lymphocyte proliferation and mouse plaque-forming cell response via an opioid receptor mechanism.

The effects of opioid peptides on immune responses were investigated. It was found that beta-endorphin (beta-END) can depress proliferative responses to PHA in rat splenocytes but enhance those in mice, and it could also inhibit the plaque-forming cell (PFC) response to sheep red blood cells when mouse splenocytes immunized in vivo were cultured in vitro with the peptide. The peptide antagonist naloxone was able to reverse beta-END suppression of the PFC response. The data indicate that beta-END suppresses antibody production or secretion via a specific opioid-receptor-mediated mechanism.

Animals↗
PubMed1994

[Report on the first nationwide survey of the distribution of human parasites in China. 1. Regional distribution of parasite species].

A nationwide (Taiwan Province not included) survey of the distribution of human parasites in China during 1988-1992 was conducted under the auspices of the Ministry of Public Health, with stratified masses randomly sampling. A total of 2,848 pilot sites in 726 counties with a population of 1,477,742 were surveyed, according to unified standard, unified diagnostic method and control quality. The overall infection rate of parasites was 62. 632%. Among them, the infection rate was over 50% in 17 provinces/autonomous regions/municipalities (P/A/M), over 80% in Hainan, Guangxi, Sichuan, Fujian, Zhejiang and Guizhou, being highest in Hainan (94. 735%). Altogether 56 species were detected. Centrocestus formosanus is reported for the first time at home, Echinochasmus liliputanus and Echinostoma angustitestis are reported for the first time at home and abroad. Echinochasmus fujianensis is a new species. E. histolytica, G. lamblia, A. lumbricoides, whipworm and pinworm were distributed nationwide, while Cysticercus (27 P/A/M), Taenia (27), hookworm (26), Balantidium coli (22), Clonorchis sinensis (22), Paragonimus westermani (21), H. diminuta (21), Echinococcus (18), H. nana (17), Fasciolopsis buski (16), T. spiralis (12) were distributed non-nationwide. A preliminary suggestion on intervention of the common and/or most detrimental parasitic diseases was submitted, including hydatidosis, taeniasis, cysticercosis, clonorchiasis, paragonimiasis, trichinellosis, hookworm disease, ascariasis, trichuriasis and enterobiasis.

Animals↗
PubMed1994

Evaluation of defined antigen vaccines against Schistosoma bovis and S. japonicum in bovines.

Our objective is to contribute to the development of defined antigen vaccines for schistosomiasis by evaluating the protective efficacy of Schistosoma bovis and S. japonicum antigens in their natural bovine hosts. Antigens under evaluation include some already identified as vaccine candidates: glutathione S-transferases (GSTs); KLH, which shares protective epitopes with the protective antigen GP38 of S. mansoni; and Sj23, the analogue of the vaccine candidate Sm23 antigen. In another approach, since crude freeze/thaw schistosomular antigen plus BCG(F/T vaccine) has proved protective against S. japonicum in bovines, as it was against S. mansoni in mice, we are carrying out further evaluations both of this crude antigen and of recombinant-derived paramyosins. In a third line of work, novel vaccine candidate antigens identified by screening our cDNA libraries with various passively protective animal sera are being evaluated in animal experiments. In the Sudan we have shown that vaccination of calves with either native S. bovis GSTs or KLH induces high levels of fecundity-suppression without causing a significant reduction in adult worm recoveries. Therefore, recombinant-derived S. bovis 28kD GST is now being evaluated, as are the effects of combined GST/KLH vaccination. In China, sheep have been vaccinated with either S. japonicum GSTs, with KLH, or with the F/T vaccine, as a prelude to trials in bovines. As judged by adult worm recoveries, each type of vaccine induced significant protection, and there was also evidence, particularly with the GST and F/T vaccines, of fecundity-suppressive effects. As with the S. bovis/cattle system therefore, both GST and KLH showed protective effects against S. japonicum in sheep.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Ultrastructural observations of the anterior chamber angle tissues in congenital glaucoma.

Eighteen trabeculectomy specimens of congenital glaucoma were examined by light and transmission electron microscopy. The results showed that the primary anomalies in congenital glaucoma included the developmental defects of trabecular meshwork, excessive collagen fibrils in the trabecular matrix, shifting forward of ciliary muscle fibres and persistent mesenchymal tissues in the anterior-chamber angle. The authors also pointed out the importance of the secondary lesions of the trabecular meshwork in the pathogenesis of congenital glaucoma.

Anterior Chamber↗
PubMed1994

[Clinicopathological analysis of rhabdomyosarcoma of the ocular adenexa].

12 cases including 11 males and 1 female of rhabdomyosarcoma of ocular adenexa were analysed. The average age of the patients was 4.2 years. 9 cases of lesion were located in the orbit, 2 in the eyelid and 1 in conjunctiva. Pathologically 8 cases were embryonal forms, 2 alveolar, 2 polymorphic. Immunohistochemical studies were performed in 8 cases, which showed desmin positive. Myoglobin presented strong or weak positive in 5 cases, suspicious positive in 3 cases. The clinical manifestation, prognosis and treatment were briefly discussed.

Child↗
PubMed1994

Improvement in the binding of cobrotoxin to microtiter plates by glutaraldehyde at neutral pH.

The coating of the wells of microtiter plates with cobrotoxin in Tris (pH 9.8) or PBS (pH 7.2) buffer was assessed by enzyme-linked immunoassay (ELISA). It was found that the poor binding in neutral buffer was improved by adding glutaraldehyde (GA), and the bound amount reached the same extent as that measured with alkali buffer. The optimal concentration of GA was approx. 0.02%. A decrease in optical density was observed with GA concentration higher than 0.02%. This may result from the modification of cobrotoxin by GA, which induced a decrease in the antigenicity of the cobrotoxin as revealed by competitive immunoassay. This study implies that the coating of physiological samples with GA for ELISA may be carried out with physiological buffers without the need to change the buffer to one of alkaline pH.

Antibodies↗
PubMed1994

Fatty acids as determinants of triglyceride and cholesteryl ester synthesis by isolated hepatocytes: kinetics as a function of various fatty acids.

Triglyceride synthesis by hepatocytes is currently thought to be the rate-limiting step for lipoprotein formation. In order to determine whether triglyceride and cholesteryl ester syntheses in hepatocytes are sensitive to physiological fluctuations of serum fatty acids, the fatty acid dependence of these pathways was examined. Uptake of various fatty acids and incorporation into triglyceride and cholesteryl esters were studied in isolated rat hepatocytes. Rates were determined under conditions of linear incorporation and related to the concentrations of total and unbound fatty acid in a mixture of fatty acids and albumin. The findings were: pathways for triglyceride and cholesteryl ester synthesis saturated at unbound fatty acid concentrations (or fatty acid albumin ratios) within the range of serum values and thus would be acutely modulated by fluctuations in serum fatty acids. Addition of cholesterol to the medium increased cellular cholesterol, but did not alter rates of cholesterol esterification, suggesting that endogenous cholesterol synthesis provided the needed substrate. Oleate, palmitate, and linoleate were comparable in their saturation kinetics and ability to support triglyceride and cholesteryl ester synthesis. Consequently, their binding affinity for serum albumin would determine their lipid-incorporation rates. On this basis, in humans, oleate would yield the lowest rates as it has the lowest unbound fatty acid at each fatty acid-albumin ratio. Stearate, in contrast to the other fatty acids, was poorly esterified into neutral lipids by hepatocytes. Poor hepatic metabolism of stearate most likely explains previous findings of a hypocholesteremic effect of diets high in stearate as compared to other saturated fatty acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Elevated thrombomodulin plasma levels as a result of endothelial involvement in plasmodium falciparum malaria.

We used thrombomodulin (TM) to assess the participation of the vascular endothelium in human Plasmodium falciparum (P.F.) malaria. Before therapy TM plasma levels were elevated in P.F. malaria and fell to normal values during therapy. Parasitemia, TNF alpha, elastase and TAT levels correlated directly with TM. Elevated TM levels can not be explained by increased synthesis, since incubating HUVEC with pretherapy serum of patients with P.F. malaria, but not reconvalescence serum, suppressed TM transcription. This was partially prevented by adding a TNF alpha neutralizing antibody to patient serum before incubation with HUVEC. However, TNF alpha does not release TM from cultured HUVEC in vitro. Coincubation of HUVEC with pretherapy serum together with neutrophils resulted in endothelial cell destruction, which could be partly prevented by a TNF alpha neutralizing antibody. Hence the increase of TM during P.F. malaria might reflect the concerted action of cytokines and neutrophils on HUVEC.

Antimalarials↗
PubMed1994

Induction of differentiation in human promyelocytic HL-60 leukemia cells activates p21, WAF1/CIP1, expression in the absence of p53.

The melanoma differentiation associated gene, mda-6, which is identical to the P53-inducible gene WAF1/CIP1, encodes an M(r) 21,000 protein (p21) that can directly inhibit cell growth by repressing cyclin dependent kinases. mda-6 was identified using subtraction hybridization by virtue of its enhanced expression in human melanoma cells induced to terminally differentiate by treatment with human fibroblast interferon and the anti-leukemic compound mezerein (Jiang and Fisher, 1993). In the present study, we demonstrate that mda-6 (WAF1/CIP1) is an immediate early response gene induced during differentiation of the promyelocytic HL-60 leukemia cell line along the granulocytic or macrophage/monocyte pathway. mda-6 gene expression in HL-60 cells is induced within 1 to 3 h during differentiation along the macrophage/monocyte pathway evoked by 12-0-tetradecanoyl phorbol-13-acetate (TPA) or 1,25-dihydroxyvitamin D3 (Vit D3) or the granulocytic pathway produced by retinoic acid (RA) or dimethylsulfoxide (DMSO). Immunoprecipitation analyses using an anti-p21 antibody indicate a temporal induction of p21 protein following treatment with TPA, DMSO or RA. A relationship between rapid induction of mda-6 gene expression and differentiation is indicated by a delay in this expression in an HL-60 cell variant resistant to TPA-induced growth arrest and differentiation. A similar delay in mda-6 gene expression is not observed in Vit D3 treated TPA-resistant variant cells that are also sensitive to induction of monocytic differentiation. Since HL-60 cells have a null-p53 phenotype, these results demonstrate that p21 induction occurs during initiation of terminal differentiation in a p53-independent manner. In this context, p21 may play a more global role in growth control and differentiation than originally envisioned.

Cell Differentiation↗
PubMed1994

Measuring lung shunting in hepatocellular carcinoma with intrahepatic-arterial technetium-99m macroaggregated albumin.

UNLABELLED: With increased use of intraarterial administration of chemotherapeutic and radioactive particulate agents, it is necessary to assess agent delivery in the lung. METHODS: Technetium-99m-labeled macroaggregated albumin (99mTc-MAA) delivered through the hepatic artery was used to determine the degree of lung shunting in 125 patients with hepatocellular carcinoma (HCC). RESULTS: The percentage of lung shunting varied among patients and it ranged from less than 1% to 67.2%, with a median of 8.1%. The degree of shunting depended on the vascularity of the tumors but not on the tumor size. The effect of angiotensin II on lung shunting was tested on six patients and there was no significant difference found between those patients who were pre-treated with angiotensin II and those who were not. One patient who underwent a liver resection, had a significant decrease in lung shunting from 28.5% to less than 1% after surgery. CONCLUSION: The lack of effect of angiotensin II together with the almost complete ablation of lung shunting by tumor resection suggested neoplastic blood vessels were responsible for the shunting.

Angiotensin II↗
PubMed1993

Combined anti-CD2 and anti-CD3 receptor monoclonal antibodies induce donor-specific tolerance in a cardiac transplant model.

Administration of mAb against either the CD2 or CD3 receptor prolongs graft survival in CBA recipients in a heterotopic, nonvascularized cardiac transplant model, whereas the combination of mAb produces indefinite survival. Combined alpha-CD2 plus alpha-CD3 mAb synergistically prolonged allograft survival indefinitely for C57BL/6 donor hearts (> 150 vs 13.4 +/- 0.5 days for controls, p < 0.001, Wilcoxon's sign rank). All second donor-specific C57BL/6 allografts survived > 100 days (p < 0.001) without any additional immunosuppression. Third-party BALB/c allografts were rejected in a first set fashion (14.2 +/- 0.5 days). Anti-CD2 mAb of other epitopic specificities and isotypes demonstrate equivalent immunosuppressive capacity. The combination of mAb resulted in indefinite graft survival in other strain combinations. Therefore, these results are not restricted to a particular alpha-CD2 mAb or MHC combination. Combinations of alpha-CD2 plus mAb with specificities other than to CD3 did not result in tolerance, showing that the CD2-CD3 interaction was critical for tolerance induction. CTL and MLR responses from tolerant animals were normal both to H-2b and H-2d stimulators, indicating that clonal deletion of effector T cells did not occur. Adoptive transfer of naive recipient type cells broke tolerance, showing that graft adaptation was not the major determinant of tolerance maintenance. Flow cytometric analysis demonstrated that tolerance was not associated with deletion of T cells. The results imply that the mechanism of tolerance induction is related to suppression and/or anergy of helper and effector cells at the time of allografting, whereas maintenance of tolerance is associated with anergy in the Th cell compartment.

Animals↗
PubMed1993

Production and characterization of soluble and transmembrane murine CD2. Demonstration that CD48 is a ligand for CD2 and that CD48 adhesion is regulated by CD2.

The baculovirus expression vector was used to produce full length, two amino-terminal Ig-like extracellular domains, and one amino-terminal Ig-like extracellular domain soluble murine CD2 products. The products were monomeric, glycosylated, and of the correct predicted m.w. Sf9 insect cells infected with recombinant baculovirus encoding the full length construct display cell surface CD2 by flow cytometry and rosette with murine cell lines that express the ligand for CD2. Uninfected Sf9, wild-type baculovirus-infected Sf9, and Sf9 expressing truncated products do not display cell surface CD2 nor do these latter Sf9 bind to murine cell lines. Cell binding is inhibited by anti-CD2 mAb. All CD2 products possess ligand binding activity since purified preparations of these block cell adhesion. All CD2 antigenic epitopes are close to the ligand binding site because all mAb tested can inhibit cell adhesion. The ligand for CD2 is shown to be CD48. Only CD48+ cell lines can bind CD2+ Sf9 and this is inhibited by anti-CD48 mAb. Antibodies against the closely related cell surface Ag Ly-6A.2 and Ly-9.2 do not inhibit binding. Purified, soluble CD2 also inhibits the binding of anti-CD48 mAb to the cell surface. Unexpectedly, additional mAb blocking studies show that CD2 on the surface of CD48+ cell lines influences adhesion to CD2+ binding partners. The use of cells expressing CD2 and/or CD48 provides evidence for a cis CD2-CD48 interaction on the cell surface in which CD2 negatively regulates CD48 adhesion properties.

Animals↗
PubMed1993

The subunit location of magnesium in cytochrome c oxidase.

The magnesium ion in bovine heart cytochrome c oxidase can be depleted up to 75% by heat treatment of the enzyme at 43 degrees C followed by dialysis against EDTA buffer solution. The magnesium-depleted enzyme so obtained retains 40% of the activity of the native enzyme. This is the first attempt to deplete magnesium ion from bovine heart cytochrome c oxidase without denaturation of the protein. Magnesium depletion exposes at least one carboxyl group on subunit IV for labeling by N-cyclohexyl-N'-(4-dimethylaminonaphthyl)carbodiimide (NCD-4). The NCD-4 labeling of subunit IV of the magnesium-depleted enzyme is significantly enhanced relative to what is observed for the native and heat-treated oxidase, suggesting that the magnesium ion is located in subunit IV with at least one carboxyl ligand. By comparing the activity of the magnesium-depleted enzyme with that of a control sample of heat-treated oxidase, the influence of divalent magnesium on the activity of the enzyme is assessed.

Amino Acid Sequence↗
PubMed1993

Establishment of National Quality Control Reference Panels and Requirements for Hepatitis B diagnosis reagents in China.

A National Quality Control Reference Panel for Hepatitis B Diagnostic Kits has been established. Markers for these standards which were prepared include National Standards for HBsAg and anti-HBs calibrated against WHO International Standards. In addition, Reference Panels for HBeAg, anti-HBe, anti-HBc, anti-HBc IgM and HBV were established and National Requirements set. These panels have been used for the nationwide evaluation of HB kits and for licensing purposes.

China↗
PubMed1993

Phase II study of high-dose ifosfamide in hepatocellular carcinoma.

A phase II study of high-dose ifosfamide in hepatocellular carcinoma was conducted among 17 Chinese patients. The dose of ifosfamide used was 2.5 g/m2 daily given as a continuous infusion for 5 days. In all, 15 patients were evaluable for tumour response. There was no complete or partial responder. The treatment was well tolerated. The most frequent toxicity was alopecia, which occurred in 11 patients, and 5 patients developed mild haematological toxicity. There was no evidence of liver or bladder toxicity. Overall, 14 patients were evaluable for survival. The median survival was 92 days (range, 30-568 days). We conclude that high-dose ifosfamide is well tolerated but ineffective in hepatocellular carcinoma in Chinese patients.

Adult↗
PubMed1993

Abundant expression of transforming growth factor-beta 1 and -beta 2 by Hodgkin's Reed-Sternberg cells and by reactive T lymphocytes in Hodgkin's disease.

The depressed cellular immunity observed in patients with Hodgkin's disease (HD) has been attributed to production of transforming growth factor (TGF)-beta or TGF-beta-like substances by Hodgkin's Reed-Sternberg (H-RS) cells. The TGF-beta produced by L-428 cells (an H-RS cell line) is a 130-kd molecular weight glycoprotein that apparently differs from the TGF-beta (molecular weight, 25 kd) produced by most lymphoid and hematopoietic cells. Among several distinct types of TGF-beta that have been purified, only TGF-beta 1 and TGF-beta 2 have thus far been identified in hematopoietic cells. By using monoclonal antibodies (1D11 and 3C7) and oligonucleotide probes specific for TGF-beta 1 and TGF-beta 2, were confirmed that a cultured H-RS cell line, KM-H2, can produce both TGF-beta types, whereas another line, HDLM-1, produces only TGF-beta 1. Despite the abundance of mRNA in both of these cells, only small amounts of TGF-beta activity were detected, probably because of rapid degradation of TGF-beta 1 mRNA by specific nuclease. No degraded TGF-beta 2 RNA products were observed in KM-H2 cells. The TGF-beta produced by both types of H-RS cells had a molecular weight of approximately 25 kd. In tissues expression of TGF-beta was observed in a small portion (30%) of H-RS cells in 16 of 20 cases examined. A large number of small to medium-sized lymphoid cells (T lymphocytes) in tissues involved by HD also were positive for TGF-beta. These results indicate that there is functional heterogeneity among H-RS cells, and that H-RS cells are not the only source of TGF-beta in tissues involved by HD. Hodgkin's Reed-Sternberg cells are known to secrete several other cytokines, including interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha. These cytokines could be responsible for the increased number of T lymphocytes in tissues involved by HD. Furthermore, T lymphocytes can respond to IL-1 and IL-6 secreted by H-RS cells by increasing their production of TGF-beta. Abundant expression of TGF-beta by T lymphocytes was not observed in lymphoid tissues other than those involved by HD.

Base Sequence↗