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Biomedical subjects

S P Lin

Publications and source records attributed to S P Lin.

At least 19 recordsLinked to original sources
PubMed2001

Complete genome sequence of an M1 strain of Streptococcus pyogenes.

The 1,852,442-bp sequence of an M1 strain of Streptococcus pyogenes, a Gram-positive pathogen, has been determined and contains 1,752 predicted protein-encoding genes. Approximately one-third of these genes have no identifiable function, with the remainder falling into previously characterized categories of known microbial function. Consistent with the observation that S. pyogenes is responsible for a wider variety of human disease than any other bacterial species, more than 40 putative virulence-associated genes have been identified. Additional genes have been identified that encode proteins likely associated with microbial "molecular mimicry" of host characteristics and involved in rheumatic fever or acute glomerulonephritis. The complete or partial sequence of four different bacteriophage genomes is also present, with each containing genes for one or more previously undiscovered superantigen-like proteins. These prophage-associated genes encode at least six potential virulence factors, emphasizing the importance of bacteriophages in horizontal gene transfer and a possible mechanism for generating new strains with increased pathogenic potential.

Bacteriophages↗
PubMed2001

Galloway-Mowat syndrome: a glomerular basement membrane disorder?

We report a female infant with Galloway-Mowat syndrome. In addition to the characteristic dysmorphic appearance, neurological anomalies and early-onset nephrotic syndrome, she had arachnodactyly, an observation thus far reported uniquely in Taiwan. Also, her elder sister had the same condition. Renal pathology on light microscopy showed cystic dilatation of the renal tubules. Electron microscopy showed an irregular glomerular basement membrane and effacement of foot processes. This observation suggests that malformation of the glomerular basement membrane may cause the glomerulopathy in Galloway-Mowat syndrome.

Basement Membrane↗
PubMed2001

In vivo hatching phenomenon of mouse blastocysts during implantation.

PURPOSE: To determine whether the blastocyst zona shedding process within the murine uterine cornus in vivo is due to a global lytic process caused by uterine proteolytic enzyme, or is triggered by the blastocyst hatching process as observed in vitro. METHODS: Fifty-one female ICR mice aged 5-8 weeks were used for this study. From 8:00 p.m. of the 4th day postcoitus to 7:00 p.m. of the 5th day postcoitus, the uterine cornua of 51 mice were isolated at 30-min intervals. Blastocysts within the uterine cornua were flushed out with a balanced solution under the dissecting microscope. The stages of blastocyst development and the proportion of hatching or hatched blastocysts and the discarded zona pellucida (ZP) were inspected and counted. RESULTS: A total of 672 blastocysts were recovered from the uterine horns of the 51 mice. They were divided into six groups according to the blastocyst developmental stages (before or after ZP escape; before or after the initiation of implantation). Group I represents the earliest embryonic stage and Group VI represents the most advanced blastocyst developmental stage during the peri-implantation period. The empty ZP recovery rates (number of discarded ZP/all hatched blastocysts) were 52.3%, 21.5%, 17.2%, 6.6%, 1.6%, and 0% in Groups I-VI, respectively. Five hatching blastocysts out of 199 embryos in Group I were found and a 100% of ZP recovery rate was obtained from 6 of 19 mice in Groups I and II. CONCLUSIONS: The present study shows that active blastocyst hatching occurs in vivo because both hatching blastocysts and empty ZP can be found within the uterine cornua of ICR mice before implantation. The empty ZP recovery rate declined significantly, along with a progression of embryo development and implantation, implying that intrauterine zona lytic activity occurs during the peri-implantation stage.

Animals↗
PubMed2001

Tubulointerstitial nephritis associated with a novel mitochondrial point mutation.

BACKGROUND: Nephropathy caused by mitochondrial disorders is a relatively newly recognized disease. Only a few cases have been reported in the literature, and most of them are proximal tubulopathy-presenting Fanconi syndrome. Here we report on a novel mutation in two familial cases of tubulointerstitial nephropathy associated with concentrating defect. METHODS: Renal biopsy specimens were examined by light microscopy and electron microscopy. Mitochondrial genomic DNA isolated from renal biopsy specimens was amplified by polymerase chain reaction (PCR) and sequenced in its entirety. The DNA sequences were analyzed by (1) comparing with the Anderson et al's mitochondrial sequences; (2) comparing with DNA sequences obtained from 97 human controls, including both healthy individuals and patients with renal diseases; and (3) comparing with the counterparts in 90 different species. RESULTS: Dismorphic mitochondria with occasional intramitochondrial inclusions were found in the renal tubular epithelial cells. A novel mitochondrial point mutation was identified at the position 608, that is, the distal end of the anticodon stem of the tRNA(Phe) molecule. The A to G substitution at this position was not observed in 97 human controls and was found to be highly conserved in evolution. CONCLUSIONS: We have identified an A608G mutation of mitochondrial genome in two cases whose presentation include tubulointerstitial nephritis and stroke.

Animals↗
PubMed2001

Direct, longitudinal comparison of (1)H and (23)Na MRI after transient focal cerebral ischemia.

BACKGROUND AND PURPOSE: (23)Na MRI may offer new insight into the evaluation of tissue injury. We performed a direct, longitudinal, morphological comparison of (1)H T2 relaxation, (1)H apparent diffusion coefficient (ADC), (23)Na content, and histopathology after cerebral ischemia to address the hypotheses that (a) (23)Na MRI is unique in comparison to (1)H MRI, and (b) accumulation of (23)Na is an unambiguous marker for dead tissue. METHODS: Rats underwent 30 minutes of focal ischemia. MRIs of (1)H T2, (1)H ADC, and (23)Na content were acquired from 12 hours up to 1, 2, or 14 days after reperfusion. On excision, brains were stained with triphenyltetrazolium chloride (TTC). RESULTS: In all cases, the region of abnormality increased in size for 2 days. On day 5, both (1)H T2 and ADC temporarily appeared normal despite the presence of TTC-defined infarction. By comparison, the volume of tissue exhibiting abnormally intense (23)Na signal mirrored the TTC-defined infarct at all time points. CONCLUSIONS: Regions of high (23)Na content correlate well with the TTC-defined infarct and may be a quantitative in vivo marker for dead tissue. In contrast, the dynamics of the (1)H T2 and ADC make it difficult to interpret these images without additional information because they may appear normal despite infarction. Neither type of (1)H image delineates dead tissue, and none of these methods predicts the potential infarct size at early time points.

Animals↗
PubMed2001

Diagnostic screening for mucopolysaccharidoses by the dimethylmethylene blue method and two dimensional electrophoresis.

BACKGROUND: The diagnosis of a mucopolysaccharidosis (MPS) can be achieved by non-enzymatic screening methods, including two-dimensional electrophoresis (2-D EP), and the dimethylmethylene blue (DMB) method. However, the confirmation of MPS diagnosis is difficult to achieve in Taiwan due to the shortage of a well-established MPS diagnostic service. In this article, we introduce the MPS screening protocols we have already established, and also illustrate the interpretation of 2-D EP result for MPS typing determination. METHODS: Thirty-seven patients with different types of MPS were analyzed by 2-D EP and the DMB method. They were 4 with MPS I (Hurler), 15 with MPS II (Hunter), 10 with MPS III (Sanfilippo), 5 with MPS IV (Morquio), and 3 with MPS VI (Maroteaux-Lamy). RESULTS: The electrophoretic patterns of the affected glycosaminoglycans (GAGs) in different MPS were illustrated, which were the basis of MPS diagnosis. The DMB results showed a significant difference between these diseases, and the dimethylmethylene blue/creatinine (DMB/CRE) ratio of Hunter Syndrome was markedly greater than those of the Sanfilippo, Hurler, and Maroteaux-Lamy Syndrome, successively. The 2-D EP is also applicable for MPS prenatal diagnosis. One cell-free amniotic fluid with suspected Hunter Syndrome was analyzed by 2-D EP, and the results excluded the possibility of MPS which was confirmed by enzymatic study. CONCLUSIONS: The 2-D EP provides a good separation of urinary GAG, and the DMB method gives an estimation of the GAG concentration in the urine. Both of the methods are specific, sensitive, and easy to perform for MPS screening and diagnosis.

Adolescent↗
PubMed2000

Identification of a novel platelet-derived growth factor-like gene, fallotein, in the human reproductive tract.

We isolated the cDNA of a novel platelet-derived growth factor-like gene from human endometrium. The gene was named fallotein; it was 3007 bases in length, and encoded a protein of 345 amino acids. Antiserum against the fallotein protein can recognize a specific protein in the fallopian tube, with a molecular size in accordance with the anticipated size of fallotein. Fallotein mRNA is expressed in two molecular sizes, 3.8 and 2.9 kb, with the former being more abundant. High expression of the gene was found in the prostate, testis, and uterus. A weaker expression signal was found in the spleen, thymus, and small intestine, but expression of fallotein in the colon and peripheral blood leukocytes was negligible.

Amino Acid Sequence↗
PubMed2000

Analysis of the mRNA transcripts of the survival motor neuron (SMN) gene in the tissue of an SMA fetus and the peripheral blood mononuclear cells of normals, carriers and SMA patients.

Spinal muscular atrophy (SMA) is a disorder characterized by degeneration of the anterior horn cells of the spinal cord. The gene most highly associated with SMA is the survival motor neuron (SMN) gene. In this study, we present an analysis of messenger RNA (mRNA) expression of the SMN gene in peripheral blood mononuclear cells in normal subjects, SMA carriers and patients from 20 SMA families. We found at least 6-8 different transcripts of SMN gene formed by alternative splicing involving exons 3, 5 and 7. We compared transcripts from the different types of SMA and found no definite differences in transcript patterns and amounts. Normal subjects with the telomeric SMN (SMN(T)) gene only had variable splicing resulting in several transcripts, the most dominant being a transcript containing all coding regions. However, SMA patients with the centromeric SMN (SMN(C)) gene only had a higher degree of splice variation and tended to show little or no exon 7. These results demonstrate that SMN(T) and SMN(C) genes participate in alternative splicing phenomena. The different splicing patterns support the view that the SMN(T) gene is responsible for SMA disease. We also analyzed the transcripts from several tissues of an SMA fetus who had a homozygous SMN(T) gene deletion. Different splicing patterns were also found in these tissues, and were similar to the splicing pattern of leukocytes. We compared the major transcripts from exons 4 to 8 of both the SMN(T) and SMN(C) genes and found that the relative proportion varied among normal subjects, SMA carriers and patients. This approach could be used as a novel diagnostic method. We suggest that analyzing the mRNA expression of the SMN gene in peripheral blood mononuclear cells offers an apparently reliable technique for separating SMA patients, carriers, and normal individuals.

Adult↗
PubMed2000

Embryonic dormancy phenomenon in obstructed healthy mouse fallopian tubes.

PURPOSE: A mouse model of unilateral oviductal obstruction was designed to study whether healthy oviducts can support embryo development in an advanced stage toward blastocyst hatching and implantation when the embryos in the contralateral side normally move into the uterine cavity. METHODS: The oviducts of 80 female ICR mice (aged 5-8 weeks) were ligated unilaterally 12-40 hr postcoitus. The ligated oviducts were isolated from day 4 to 19.5 postcoitus. Embryos within the ligated oviducts were then flushed out to record the developmental stage and compared with the conceptuses in the contralateral uterine horns with unligated oviducts. Embryos recovered from ligated oviducts were then cultured in vitro to observe their potential for further development. RESULTS: In 33 mice, 53.4% (163/305) and 86.1% (241/280) of the morphologically normal blastocysts had hatched from the zona pellucida within the obstructed tube and contralateral uterine horns, respectively, on the 5th day postcoitus. The data demonstrated that the hatching process could take place within the obstructed fallopian tube, but the timing was delayed. From 5.5 to 19.5 days postcoitus, a total of 362 implanted embryos were obtained in unligated control uterine horns, but none of the 404 embryos in the artificially obstructed oviducts were implanted. The embryos within the ligated tubes were dormant in the hatched blastocyst stage as demonstrated by their ability to continue growing (98.2%) when removed from the oviduct to an in vitro environment. CONCLUSIONS: In this study, we demonstrate that mouse embryos can hatch, although delayed, in obstructed healthy oviducts. Tubal pregnancy is not likely to happen in artificially obstructed healthy mouse fallopian tubes, since all the viable embryos were dormant at the hatched blastocyst stage.

Animals↗
PubMed2000

The effects of brief gamete co-incubation in human in vitro fertilization.

PURPOSE: To investigate whether very short exposure of mature oocytes to sperm in vitro may affect the fertilization rates, embryo cleavage rates, and embryo quality between sibling oocytes in the same patient. METHODS: Sibling oocytes of the same patient from 23 oocyte collection cycles were randomly allocated to the study group, with a 1-hr or 3-hr sperm-oocyte incubation, or the control group with the standard overnight gamete co-incubation. The fertilization rates, cleavage rates, and subsequent embryo quality were evaluated. RESULTS: Our results showed no statistically significant differences in fertilization rates, embryo cleavage rates, and quality of the embryos between the study group and the control group. CONCLUSIONS: Since the present study showed that long exposure of the oocyte to sperm has no advantage over short exposure, we prefer shortening the oocyte-sperm incubation period for reducing the negative effect induced by nonphysiologically high concentrations of spermatozoa.

Female↗
PubMed2000

Identification and characterization of -3c-g acceptor splice site mutation in human alpha-L-iduronidase associated with mucopolysaccharidosis type IH/S.

DNA screening for mutations in the alpha-L-iduronidase (IDUA) gene was performed in a Chinese mucopolysaccharidosis type IH/S patient. The patient had two different mutations: the maternal allele has L346R (t-g transversion in codon 346) and the paternal allele has 388-3c-g (c-g transversion at position -3 of the 3' splice site of intron 2). In transfected COS-7 cells, L346R showed no appreciable IDUA activity (0.4% of normal activity), although it did not cause an apparent reduction in IDUA mRNA or protein level. The 388-3c-g mutation profoundly affects normal splicing leading to a very unstable mRNA. Expression of the IDUA cDNA containing the mutated acceptor splice site showed trace amounts of enzyme activity (1.6% of normal activity). The results provide further support for the importance of cytosine at the -3 position in RNA processing.

Animals↗
PubMed2000

Polymorphism of transmembrane region of MICA gene and Kawasaki disease.

Kawasaki disease is a febrile disease of children complicated with vasculitis of the coronary arteries and potential aneurysm formation. It has been recognized worldwide and appears to be increasing in frequency. Studies have found that Kawasaki disease is associated with major histocompatibility complex (MHC) class I B antigens. The MHC-class-I-chain-related gene A (MICA) is located near HLA-B. It has a triplet repeat microsatellite polymorphism in the transmembrane region. We investigated the microsatellite polymorphism in children with Kawasaki disease and controls. Seventy children (46 boys), age at diagnosis 1.68 +/- 1.69 years, with Kawasaki who were treated with aspirin as well as intravenous gamma-globulin were enrolled. Control subjects consisted of 154 children (87 boys), age 2.81 +/- 2.12 years. Phenotype frequency of allele A4 in patients with aneurysm formation was significantly lower than in patients without aneurysms [relative risk (RR) = 0.06, 95% confidence interval (CI) = 0.01-0.48, p = 0.00469, pc = 0.0232] and showed a similar tendency when compared with controls. Gene frequency of allele A4 was also significantly lower in patients who developed aneurysms than in patients who did not (RR = 0.07, 95% CI = 0.01-0.57, p = 0.0057, pc = 0.0282). Gene frequency of allele A5 showed a tendency to be higher in patients who developed aneurysms than in controls (RR = 2.35, 95% CI = 0.98-5.63, p = 0.0486, pc = 0. 220). Allele A5.1 tended to be negatively associated with Kawasaki disease (RR = 0.57, 95% CI = 0.35-0.93, p = 0.022, pc = 0.105). Our study showed that allele A4 was negatively associated with coronary aneurysm formation in Kawasaki disease. This suggests that allele A4 protects the children with Kawasaki disease from developing coronary aneurysms after aspirin and gamma globulin therapy.

Alleles↗
PubMed2000

Particle irradiation induces FGF2 expression in normal human lens cells.

Particle Irradiation Induces FGF2 Expression in Normal Human Lens Cells. Particle radiations, including both proton and helium-ion beams, have been used to successfully treat choroidal melanoma, but with the complication of radiation-induced cataract. We have investigated a role for radiation-induced changes in the expression of basic fibroblast growth factor (FGF2) gene expression as part of the mechanism(s) underlying lens cell injury associated with cataract. Normal human lens epithelial (HLE) cells were cultured in vitro on extracellular matrix (ECM) originated from bovine corneal endothelial cells. This study reports evidence for rapid but transient induction of FGF2 transcripts, an increase of between 5- and 8-fold, within 0.5 h after exposure to particle radiation, followed by another wave of increased transcription at 2-3 h postirradiation. Immunofluorescence results confirm the enhanced levels of FGF2 protein rapidly after exposure to protons or helium ions, followed by another wave of increased activity unique to helium at 6 h postirradiation. This second wave of increased immunoreactivity was not observed in the proton-irradiated samples. Total FGF2 protein analysis after helium-ion exposures shows induced expression of three FGF2 isoforms, with an increase of up to 2-fold in the 18-kDa low-molecular-weight species. Studies of the effects of protons on individual FGF2 protein isoforms are in progress. Several mechanisms involving a role for FGF2 in radiation-induced cataract are discussed.

Cells, Cultured↗
PubMed2000

Prenatal diagnosis of inherited satellited non-acrocentric chromosomes.

We report on the prenatal diagnosis of two sib female fetuses with a satellited short arm of chromosome 4 and a male fetus with a satellited long arm of chromosome X. The first two fetuses had a cryptic balanced translocation (4;15)(p16;p11.1) inherited from a mother carrying a satellited 4p and having an affected child with the Wolf-Hirschhorn syndrome. The third fetus had a satellited Xq, with a deletion of subtelomeric region of Xq. The mother was subsequently found to have the same satellited Xq but without the presence of a reciprocal translocation. She decided to continue the pregnancy. The proband with a satellited Xq manifested developmental delay, mental retardation, hypertelorism, ptosis of one eye, low-set ears, and hearing disturbance at age 6 months. Fluorescence in situ hybridization (FISH) with a specific telomeric or subtelomeric probe, and genetic marker analyses were used to confirm the diagnosis. Pregnant women with satellited non-acrocentric chromosomes are at risk for carrying fetuses with chromosome abnormalities. If the X chromosome is involved, the fetuses can be affected with X-linked recessive disorders including mental retardation. Detailed genetic counselling, cytogenetic studies, FISH and genetic marker analyses are useful in prenatal detection of abnormal chromosome rearrangements.

Adult↗
PubMed2000

Growth and differentiation of human lens epithelial cells in vitro on matrix.

PURPOSE: To characterize the growth and maturation of nonimmortalized human lens epithelial (HLE) cells grown in vitro. METHODS: HLE cells, established from 18-week prenatal lenses, were maintained on bovine corneal endothelial (BCE) extracellular matrix (ECM) in medium supplemented with basic fibroblast growth factor (FGF-2). The identity, growth, and differentiation of the cultures were characterized by karyotyping, cell morphology, and growth kinetics studies, reverse transcription-polymerase chain reaction (RT-PCR), immunofluorescence, and Western blot analysis. RESULTS: HLE cells had a male, human diploid (2N = 46) karyotype. The population-doubling time of exponentially growing cells was 24 hours. After 15 days in culture, cell morphology changed, and lentoid formation was evident. Reverse transcription-polymerase chain reaction (RT-PCR) indicated expression of alphaA- and betaB2-crystallin, fibroblast growth factor receptor 1 (FGFR1), and major intrinsic protein (MIP26) in exponential growth. Western analyses of protein extracts show positive expression of three immunologically distinct classes of crystallin proteins (alphaA-, alphaB-, and betaB2-crystallin) with time in culture. By Western blot analysis, expression of p57(KIP2), a known marker of terminally differentiated fiber cells, was detectable in exponential cultures, and levels increased after confluence. MIP26 and gamma-crystallin protein expression was detected in confluent cultures, by using immunofluorescence, but not in exponentially growing cells. CONCLUSIONS: HLE cells can be maintained for up to 4 months on ECM derived from BCE cells in medium containing FGF-2. With time in culture, the cells demonstrate morphologic characteristics of, and express protein markers for, lens fiber cell differentiation. This in vitro model will be useful for investigations of radiation-induced cataractogenesis and other studies of lens toxicity.

Animals↗