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Biomedical subjects

M Lin

Publications and source records attributed to M Lin.

At least 235 records · Page 13Linked to original sources
PubMed1995

Correlation of a missense mutation in the human Secretor alpha 1,2-fucosyltransferase gene with the Lewis(a+b+) phenotype: a potential molecular basis for the weak Secretor allele (Sew).

A missense mutation (A385 to T), predicting an Ile129 to Phe substitution, in the human Secretor alpha 1,2-fucosyltransferase gene was present in double dose in Lewis(a+b+) individuals, but not in Lewis(a-b+) individuals. Co-segregation of the Lewis(a+b+) phenotype with homozygosity for the mutation was also verified. These results yield a potential molecular basis for the weak Secretor allele (Sew) accounting for the Lewis(a+b+) phenotype.

Alleles↗
PubMed1995

Detection of insulin aggregates with pulsed-field gradient nuclear magnetic resonance spectroscopy.

Self-association of metal-free human insulin in aqueous solution at pH 9.4 has been studied using pulsed-field gradient (PFG) NMR spectroscopy. The diffusion coefficients were measured for two different insulin concentrations, 0.72 mM in which the dimer is the predominant species and 3 mM which is a mixture of dimer and tetramer. In the more concentrated solution, exchange between the two aggregates is slow on the NMR chemical shift time scale. As a result, the dimer and tetramer give rise to separated resonances in the aromatic region of the 1H NMR spectrum. The diffusion coefficient determined for the tetramer by PFG NMR is 1.07 x 10(-6) cm2 s-1 at 298 K, while that for the dimer is 1.38 x 10(-6) cm2 s-1. The hydrodynamic diameters calculated for the tetramer and dimer are 46 and 36 A, respectively, which are in good agreement with those measured by dynamic light scattering. The advantage of PFG NMR for the measurement of insulin aggregation in these solutions results from the chemical shift selectivity which allows diffusion coefficients to be directly calculated for the different aggregates. The T1 and T2 relaxation times of the dimer and tetramer aromatic protons were also measured in order to optimize the parameters of the PFG NMR experiment and correctly interpret the results of the measured spectra.

Diffusion↗
PubMed1995

Treatment of platelet alloimmunization with intravenous immunoglobulin in a child with aplastic anemia.

A 9-year-old girl with severe refractory aplastic anemia had become refractory to platelet transfusion due to platelet alloimmunization. As a result, a huge right parieto-temporo-occipital cerebral hematoma and a subarachnoid hemorrhage subsequently occurred. Intravenous immunoglobulin (IVIG) (Green Cross, Taiwan) at a dose of 0.4 g/kg/day for 5 days, followed by another 3 doses during the following 5 days, and combined with large-dose platelet transfusions effectively controlled the bleeding by elevating the platelet count to above 100 x 10(3)/mm3. The patient soon recovered with only a mild sequela. Two months later, because of multiple caries and a periodontal abscess, dental extraction needed to be performed. IVIG (0.4 g/kg/day x 6 days) enabled surgery to proceed by elevating the platelet count to above 55 x 10(3)/mm3, and no bleeding complications occurred during or after the procedure. The potential benefit of high-dose IVIG in modulating platelet alloimmunization is a result of increasing the survival of transfused platelets. Thus, this therapy is recommended when patients with platelet alloimmunization have critical bleeding episodes or undergo surgical procedures.

Anemia, Aplastic↗
PubMed1995

Internal image rabbit anti-idiotypic antibody detects sheep antibodies to the bluetongue virus core protein VP7.

BACKGROUND: Rabbit polyclonal anti-idiotypic antibodies (anti-Id) were generated against three murine monoclonal antibodies (MAbs) specific for the group-specific antigen VP7 of bluetongue virus (BTV) by the sequential immunization method. It was demonstrated by serological tests that part of the anti-Id possesses the characteristics of internal image anti-Id. By affinity purification against the individual MAbs, the internal image anti-Id, designated RAb2-A, was isolated and identified as specific for the MAb, M1875. OBJECTIVES: To examine the ability of RAb2-A to detect sheep anti-VP7 antibodies by recognition of the common idiotype (Idx). STUDY DESIGN: Affinity-purified RAb2-A IgG, along with VP7, was applied on the solid-phase of ELISA plate and the membrane for Western blot analysis to detect anti-VP7 antibodies from sheep that were immunized with VP7 or were experimentally infected with BTV. An inhibition ELISA was employed to determine whether sheep anti-VP7 and M1875 recognize the same or similar epitope(s). RESULTS: RAb2-A recognised the Idx on anti-VP7 antibodies from sheep that were either immunized with VP7 or experimentally infected with BTV. Specificity of the reaction was confirmed by the observation that RAb2-A did not react with normal sheep serum or sheep antibodies against epizootic haemorrhagic disease of deer virus, a bluetongue-related disease virus in the Orbivirus genus. CONCLUSION: The ability of RAb2-A to detect anti-VP7 antibodies through recognition of the Idx suggests that RAb2-A can be used as a probe to detect anti-BTV antibodies.

Animals↗
PubMed1995

Identification of variant glycophorins of human red cells by lectinoblotting: application to the Mi.III variant that is relatively frequent in the Taiwanese population.

BACKGROUND: Detection of normal and variant glycophorin electrophoretic bands with T- and Tn-specific lectins is based on the possibility of glycophorin transformation into T or Tn antigens by simple chemical modifications in the blot. STUDY DESIGN AND METHODS: Human red cell membrane proteins were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and blotted onto nitrocellulose. The blots were submitted to mild acid hydrolysis (desialylation of glycophorins exposing T antigens) and then to Smith degradation (degalactosylation of asialo-glycophorins exposing Tn antigens). The modified glycophorin bands were detected with biotinylated lectins and horseradish peroxidase-conjugated avidin. RESULTS: The lectins from Artocarpus integrifolia (jacalin, anti-T/Tn), Amaranthus hybridus (anti-T), Salvia sclarea (anti-Tn), and Vicia villosa (anti-Tn) were used. The lectins detected normal glycophorin bands in control and variant red cells and characteristic additional bands in Mi.III (GP.Mur) red cells. The sensitivity of the method is comparable to that obtained by immunoblotting with glycophorin monoclonal antibodies. Comparison of the electrophoretic mobility of normal and variant bands is helpful in the classification of glycophorin variants. CONCLUSION: Lectinoblotting, based on carbohydrate recognition, enables the detection in a red cell sample, with high sensitivity, of all normal and variant glycophorin bands. The method can be also applied to other purposes, such as the identification of poly-O-glycosylated glycoproteins in other cells or the characterization of glycosylation of glycophorins and other poly-O-glycosylated proteins.

Erythrocyte Membrane↗
PubMed1995

Development of the gonads in the triploid (ZZW and ZZZ) fowl, Gallus domesticus, and comparison with normal diploid males (ZZ) and females (ZW).

Gonadal development in fowls aged from 1 day to more than 4.5 years was studied in 63 ZZW and 16 ZZZ triploid crossbreds and compared with normal diploid males (ZZ) and females (ZW). In the ZZW fowl, the right gonad developed into a testis (although this occurred earlier in the ZZ genotype), and a structurally-abnormal excurrent duct system containing some malformed spermatids and spermatozoa was associated with the gonad of young adults. The left gonad was an ovotestes at hatching and no excurrent ducts were associated with it. The ovarian component was much less developed than that in the ZW genotype-it started to degenerate by 1 week of age, and most of the oocytes had disappeared by about 3 weeks of age. The seminiferous tubules developed in the medullary region, but only abnormal spermatozoa were produced. Leukocytes infiltrated both gonads at about 9 months of age and the seminiferous epithelium had degenerated in most fowls over 1 year old. In ZZZ fowl, gonadal and excurrent duct development was normal, but occurred earlier than in the ZZ genotype. However, meiosis and spermiogenesis were abnormal and malformed spermatozoa were produced. The heads of spermatozoa from the ducts deferens were about 1.4-times longer in the ZZZ genotype than in the ZZ genotype, indicating that the former may be producing some diploid spermatozoa.

Animals↗
PubMed1995

Inhibition of collagenase type I expression by psoralen antisense oligonucleotides in dermal fibroblasts.

Type I collagenase plays an important role in both tumor metastasis and the remodeling of connective tissue in normal human skin, during wound healing, for example, and may participate in the pathophysiology of some dermatological diseases such as skin cancer and a chronic blistering disease, recessive dystrophic epidermolysis bullosa. In an effort specifically to inhibit collagenase expression, we have designed phosphorothioate antisense oligonucleotides, linked at the 5' ends with photoreactive 4'-(hydroxyethoxymethyl)-4,5',8-trimethyl-psoralen (HMT), and directed them against the 5' end of the collagenase mRNA. Two antisense-HMT molecules targeting a region overlapping the initiation codon were compared. Only one contained the HMT moiety targeting a 5'TpA on its complementary sense strand, and we observed greater than 50-fold improvement on the cross-linking of this antisense oligonucleotide to its target sequence after ultraviolet A (UVA) irradiation. Likewise, sequence complementary to the 5'TpA target was also required to demonstrate specific inhibition of in vitro translation of collagenase mRNA. Tissue culture experiments, conducted by incubation of collagenase-specific antisense-HMT oligonucleotides with fibroblasts in monolayer or in 3-dimensional dermal equivalents, showed lowered collagenase levels 24 h after UVA irradiation as compared to controls. Initial screening of antisense oligomers for specific hybridization and photo-cross-linking is a useful step in the design of antisense oligonucleotides, and allowed us to design an HMT-linked antisense phosphorothioate oligonucleotide that specifically inhibits the expression of fibroblastic collagenase.

Base Sequence↗
PubMed1995

Differences in colorectal cancer between China and Japan: a clinical and histological study of two groups of cases.

It is well known that most tumours are attributed to life style, especially the tumours of the digestive system. Clinical and histopathological investigation of tumours in different human groups and societies, and analysis of the variations will provide evidence for this, and is one of the approaches to study carcinogens. Clinical data obtained from 391 patients with colorectal cancer at the Sakai Municipal Hospital, Japan, and Shanghai Jinshan Hospital and Cancer Hospital, China, from 1987 to 1992, included the sex, age and tumour subsite. Sections of histological specimens were also retrieved. The results were compared between two countries. The average age of patients with colorectal cancer in Shanghai was 8.5 years less than in the Sakai group. The age peak of the former was 51-60, and in the latter, 61-70 years. The most frequent site of the cancer in the Shanghai group was the rectum, contrasting with the higher percentage of sigmoid colon cancer in Sakai group. There was also a significant difference in histological subtype of the cancer between the two groups. Mucinous adenocarcinoma was notably more common in the Shanghai group than in the Sakai group, and the high frequency was mainly in the colon. All of the variations were suggested to be attributable to differing socioeconomic circumstances and lifestyle, especially the dietary habits of the countries.

Adult↗
PubMed1995

Neonatal alloimmune thrombocytopenia in Taiwan due to an antibody against a labile component of HPA-3a (Baka).

We report on two siblings who developed severe neonatal alloimmune thrombocytopenia (NAIT) due to an alloantibody against a labile component or components of the HPA-3a (Baka) antigen. The antibody reacted only with fresh, unfixed platelets by the solid-phase red cell adherence test, immunofluorescence test and mixed passive haemagglutination test. In the latter method, weakly fixed platelets also gave a weak positive reaction. Monoclonal-antibody-specific immobilization of platelet antigens and immunoblotting tests gave negative results. Our findings may possibly help to explain why in some cases of NAIT no platelet-specific antibody is demonstrable in tests with fixed or solubilized platelets.

Antibodies, Monoclonal↗
PubMed1995

The Le(a) antigen and neonatal hyperbilirubinemia in Taiwan.

Neonatal jaundice is known to be more severe in Taiwanese infants than in Caucasian infants. Although ABO fetomaternal incompatibility and glucose-6-phosphate dehydrogenase deficiency have been shown to play a role in the etiology of neonatal jaundice in some Taiwanese infants, the etiology in the majority of cases is unknown. In this study we found that in Taiwanese newborn infants, the red cell Le(a) antigen appeared later in infants who were jaundiced (peak serum bilirubin levels of > 12 mg/dl during the first week of life) than in infants who were not. However, the Leb antigen, and hence the transferase encoded by the Se and Se(w) genes, did not appear to be similarly involved in the etiology of physiological jaundice. Thus it would appear that the Le gene-specified transferase is less active or has a delayed function, in jaundiced infants. The relationship between the Le gene-specified transferase and bilirubin has yet to be established.

Asian People↗
PubMed1995

Roles of oxidative stress in activation of Kupffer and Ito cells in liver fibrogenesis.

An increasing body of experimental evidence is emerging to incriminate oxidative stress as a pivotal signal for liver fibrogenesis. This paper reviews the results from our studies testing this hypothesis. In the rat model of alcoholic liver disease, the importance of oxidative stress was supported by marked accentuation of liver fibrosis by dietary supplementation of iron, a pro-oxidant, and the significant correlation of the liver malondialdehyde (MDA) and 4-hydroxynonenal (4HNE) levels with the hepatic collagen accumulation. Both MDA and 4HNE adduct epitopes were detected intensely and diffusely in close association with collagen deposition. The direct cause and effect relationship between MDA/4HNE and Ito cell stimulation was indicated by the demonstration of Ito cell collagen gene induction by these aldehydes in culture. In primary cultures of rat Kupffer cells (KC), addition of antioxidants such as alpha-tocopherol acetate and succinate suppressed mRNA expression and the release of interleukin (IL)-6 and tumour necrosis factor alpha (TNF alpha). In rats with biliary fibrosis, an increase in the liver MDA level was accompanied by enhanced mRNA expression of procollagen alpha 1(I) and transforming growth factor beta 1 in Ito cells; and that of TNF alpha and IL-6 in KC. Furthermore, the gel shift assay of KC nuclear extracts showed enhanced NF-kB DNA binding activity. These results support the proposal that enhanced oxidative stress constitutes an important signal for activation of Kupffer and Ito cells in experimental liver fibrogenesis.

Aldehydes↗
PubMed1995

Natriuretic peptides inhibit angiotensin II-induced proliferation of rat cardiac fibroblasts by blocking endothelin-1 gene expression.

The present study was aimed to test the role of endothelin-1 (ET-1) as a possible autocrine/paracrine growth factor for cardiac fibroblasts, and to examine its interaction with cardiac natriuretic hormones. Expression of preproET-1 (ppET-1) mRNA by cultured cardiac fibroblasts from neonatal rats was demonstrated by Northern blot analysis using cDNA for rat ppET-1 as a probe. Angiotensin II (ANG II) and ET-1 transiently (30 min) increased steady-state ppET-1 mRNA levels in cardiac fibroblasts. Both ET-1 and ANG II significantly stimulated [3H] thymidine incorporation into cardiac fibroblasts, whose effects were dose-dependently inhibited by an ETA receptor antagonist (BQ123), BQ123 also inhibited both ET-1- and ANG II-induced ppET-1 mRNA expression. Both atrial and brain natriuretic peptides (ANP, BNP), which activate particulate guanylate cyclase, inhibited ppET-1 mRNA expression and [3H]thymidine incorporation stimulated by ANG II and ET-1. Sodium nitroprusside, a soluble guanylate cyclase activator, and 8-bromocyclic GMP, a membrane-permeable cGMP derivative, similarly inhibited ppET-1 mRNA expression and [3H]-thymidine incorporation. BNP was more potent than ANP to inhibit ANG II- and ET-1-stimulated DNA synthesis, whereas BNP and ANP were almost equipotent in stimulating cGMP generation in cardiac fibroblasts. Our data demonstrated that ANG II and ET-1 upregulate ET-1 gene expression in rat cardiac fibroblasts partly via cyclic GMP-dependent mechanism, and that natriuretic peptides inhibit ANG II-stimulated proliferation of cardiac fibroblasts, possibly by inhibiting ET-1 gene expression. Our data suggest the possible role of endogenous ET-1 as an autocrine/paracrine growth factor for cardiac fibroblasts and its close interaction with natriuretic peptides in the regulation of cardiac fibrosis.

Angiotensin II↗