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Biomedical subjects

Y H Yang

Publications and source records attributed to Y H Yang.

At least 91 records · Page 5Linked to original sources
PubMed1998

Expression of CYP2M1, CYP2K1, and CYP3A27 in brain, blood, small intestine, and other tissues of rainbow trout.

Expression of five constitutive forms of cytochrome P450 [(LMC1 (CYP2M1), LMC2 (CYP2K1), LMC3, LMC4, and LMC5 (CYP3A27)] in selected tissues from sexually immature 2-year old female and male rainbow trout (Oncorhynchus mykiss) were examined at the translational level by Western blot using polyclonal antibodies raised in rabbits against those purified trout hepatic P450s. Tissues examined were from brain, liver, muscle, blood, head kidney, trunk kidney, upper intestine, stomach, heart, and gonad (ovary or testis). The results showed that the liver was the major organ for expression of all the trout P450s studied. Trunk kidney was the secondary expression site except for LMC5. Selective translational expression of these P450 isoforms or similar proteins was observed for LCM1 and LMC5 in brain; for LMC2 and LMC5 in female upper intestine; and for LMC2 in blood plasma of the fish studied under the experimental and sampling conditions.

Animals↗
PubMed1998

Glucocorticoid inhibition of adjuvant arthritis synovial macrophage nitric oxide production: role of lipocortin 1.

Nitric oxide (NO) is a mediator of inflammatory injury which is inhibited by glucocorticoids and is implicated in rheumatoid (RA) and adjuvant arthritis (AA). The glucocorticoid-induced anti-inflammatory molecule lipocortin 1 is expressed in RA synovium, but the effects of lipocortin 1 on synovial inflammation have been little studied. We investigated the effects of glucocorticoids and lipocortin 1 on inducible NO synthase (iNOS) and glucocorticoids on the induction of lipocortin 1 in AA synovial macrophages. NO production was measured by Griess assay in supernatants of day 14 AA rat synovial explants and of synovial macrophages purified from enzyme-digested synovium and treated with lipopolysaccharide (LPS) 1 microg/ml, dexamethasone (DEX) 10(-7) M, and anti-lipocortin 1 MoAb. iNOS and lipocortin 1 expression were detected by flow cytometry using specific MoAb. Cell surface lipocortin was determined by Western blot. NO was produced by all AA synovial explants and NO was released by cultured synovial macrophages (14.5 +/- 2.1 micromol/24 h). iNOS was detected in synovial macrophages (ED-1+) by permeabilization flow cytometry. LPS increased synovial macrophage NO release (P < 0.0001) and iNOS expression (P = 0.04). DEX inhibited constitutive (P = 0.002) and LPS-induced (P < 0.001) NO release and iNOS expression (P = 0.03). DEX inhibition of synovial macrophage NO was associated with induction of cell surface and intracellular lipocortin 1. Anti-lipocortin 1 MoAb treatment reduced the inhibition of NO release by DEX (P = 0.002), but had no effect on iNOS expression. These findings demonstrate a role for lipocortin I in the inhibition by glucocorticoids of AA synovial macrophage iNOS activity.

Animals↗
PubMed1998

Fusion expression of human pro-urokinase with E. coli thioredoxin.

Human pro-urokinase (pro-UK) was cloned into plasmid pET32b and fused to the E. coli thioredoxin (trxA). When expressed in E. coli AD494(DE3), the fusion protein Trx-pro-UK accumulated as insoluble inclusion bodies and amounted to 35% of total cellular proteins. When co-expressed with molecular chaperones human protein disulfide isomerase (PDI) and E. coli GroESL, all the expressed products still existed in the form of insoluble inclusion bodies.

Bacterial Proteins↗
PubMed1998

Nutritional status in acute stroke: undernutrition versus overnutrition in different stroke subtypes.

OBJECTIVES: Nutritional status in the acute stage of stroke has not been properly evaluated in different stroke subtypes. The objective of this study was to investigate the nutritional status of different subtypes of stroke patients. SUBJECTS AND METHODS: We studied 88 female patients with first-ever strokes. Strokes were divided into cerebral infarction (CI, n=67) and intracerebral hemorrhage (ICH, n=21). We measured the nutritional status of the patients in the acute stage of stroke with the use of 8 parameters including 3 biochemical and 5 anthropometric ones. These variables were assessed in stroke patients and 120 age-matched controls, and were compared with each other. RESULTS: In the acute stage of stroke, undernourishment was significantly (P=0.000) more prevalent in the ICH group (62%) than in the CI group (25%) or controls (13%). On the other hand obesity was present in 10%, 24% and 17% in patients with ICH, those with CI, and controls, respectively, which was not significantly different (P=0.461). Only abdominal skinfold thickness was significantly greater in patients with CI than in those with ICH or controls. Conclusions - Our results illustrate that undernourishment is prevalent in acute stroke patients, significantly more so in patients with ICH than in those with CI. Stroke patients, especially those with ICH, should receive special nutritional intervention starting immediately after admission.

Acute Disease↗
PubMed1998

Etiology and outcome of hydrops fetalis.

Hydrops fetalis is a morbid condition caused by a wide variety of diseases. Although treatment for some underlying pathologies is becoming available, the prognosis remains poor. To analyze the etiology and outcome of hydrops fetalis, we reviewed the records of 79 fetuses encountered at the National Taiwan University Hospital between January 1993 and October 1996. The mean +/- standard deviation gestational age at presentation was 24.9 +/- 6.3 weeks. One case was due to RhE incompatibility. Seventy-eight fetuses were diagnosed as having nonimmune hydrops fetalis; this was idiopathic in 20 fetuses. In the other 58, the causes and associated conditions were classified into eight groups: hematologic (25), cardiovascular (15), chromosomal (5), gastrointestinal (4), cystic hygroma (3), pulmonary (2), infection (2), and miscellaneous (3). One fetus with cystic hygroma also had a chromosomal abnormality (Turner's syndrome). The most common cause of nonimmune hydrops fetalis was homozygous alpha-thalassemia (31%). Twenty-nine fetuses were lost to follow-up after initial evaluation and 50 fetuses were delivered at our hospital. Of these, there were eight cases of antepartum death, 24 cases of intrapartum death, and 18 live births. Seventeen of the live-born infants were treated at our neonatal intensive care unit, of whom only seven survived.

Adult↗
PubMed1998

Ki-1 lymphoma in two children.

Childhood Ki-1 lymphoma is rarely reported in Taiwan. We present two 8-year-old girls with Ki-1 lymphoma diagnosed and treated at the National Taiwan University Hospital. The first patient presented with a neck mass with hepatosplenomegaly. The second patient initially presented with joint pain and pathologic fracture; she was later found to have bone marrow involvement. Histologic studies of both tumors revealed bizarre large cells with pleomorphic nuclei and prominent nucleoli. All these cells were immunolabeled with monoclonal antibody Ki-1. The two patients received different polyregime chemotherapy protocols followed by bone marrow transplantation (BMT); patient 1 had autologous BMT and patient 2 had allogeneic BMT. In addition, local radiotherapy and retinoic acid were tried for patient 1 but she responded poorly and died 2 years after presentation. In patient 2, although bone marrow was initially involved, allogeneic BMT was performed smoothly after tumor loading was reduced and the patient was in remission at last follow-up, 26 months after presentation. Ki-1 lymphoma in children is characterized by clinical presentations, and histologic and immunologic findings. Aggressive polyregime chemotherapy and bone marrow transplantation are treatments for this disease.

Bone Marrow Transplantation↗
PubMed1998

Severe colonic complications in acute pancreatitis.

BACKGROUND: Colonic complications in patients with acute pancreatitis may be very severe and have rarely been analyzed in Chinese patients. METHODS: We retrospectively evaluated 1,637 patients with acute pancreatitis who were admitted to the Veterans General Hospital-Taipei from January 1986 to December 1995 in order to identify those with severe colonic complications. The clinical, radiologic and pathologic features and surgical findings in these patients are reviewed. RESULTS: Eight of 1,637 patients with acute pancreatitis had severe colonic complications. Six of them were diagnosed between two and eight weeks after the onset of clinical pancreatitis. All had a Ranson's score of at least 3. Four patients, including one with hematochezia, had a strong positive reaction for occult blood in stool specimens. Computed tomography (CT) revealed necrotizing pancreatitis and colonic wall swelling in all eight patients. Colonic involvement was discovered by CT in two patients prior to surgery, one with colocutancous fistula and the other with colonic perforation. The other six patients were found to have colonic involvement incidentally at the time of laparotomy. All of the colonic involvements were located near the splenic flexure. In addition to necrosectomy, three patients underwent segmental hemicolectomy and the remaining five patients had simple closure of the perforation. Diverting loop ileostomy or colostomy was also carried out in all patients. Three patients (34%) died of overwhelming sepsis superimposed on the subsequent multiple organ failure between 44 and 122 days after the onset of pancreatitis. CONCLUSIONS: Severe colonic complications of acute pancreatitis are rare. Although preoperative diagnosis is difficult, CT may be helpful to make an early diagnosis. These complications should be suspected in patients with severe acute pancreatitis when acute lower gastrointestinal hemorrhage or positive stool occult blood is found two to eight weeks after the onset of pancreatitis or when CT reveals necrotizing pancreatitis and colonic wall swelling; this will allow early surgical intervention.

Acute Disease↗
PubMed1998

[Studies on late replication bands of giant panda (Ailuropoda melanoleuca) chromosomes].

Using the cultured giant panda (Ailuropoda melanoleuca) lymphocytes as experimental material, we carried out the terminal marking on the chromosomes which were in replication by adding BrdU (a final concentration: 10 micrograms/ml) about four hours before harvesting the cells. The chromosomes marked by BrdU were proceeded by staining with acridine orange solution (0.05%), irradiated by ultraviolet and counter-stained by Giemsa, we obtained clear chromosomes replication patterns. According to the different replication bands, every chromosome's characteristics in late replication behavior could be identified. In the two X chromosomes of female individual, one X chromosome is obviously much later than the other one. Especially in the large area near centromere on the long arm of late replicating X chromosome. In the male individual, there is also a large area on the long arm of chromosome Y which replicates very late, but the end of long arm of chromosome Y replicates much earlier.

Animals↗
PubMed1997

Prolactin regulation of mitochondrial aspartate aminotransferase and protein kinase C in human prostate cancer cells.

Citrate production is a major physiological function of the prostate that is regulated by testosterone and prolactin. Mitochondrial aspartate aminotransferase (mAAT) is a key enzyme in the metabolic pathway of prostate citrate production. In addition, prolactin stimulates expression of mAAT in the rat lateral prostate. In this report we establish the role of prolactin in the regulation of mAAT in two prostate cancer cell lines, LNCaP and PC-3. LNCaP cells respond to hormonal stimulation with increased secretion of prostate specific products. PC-3 cells, on the other hand, are testosterone independent and apparently do not respond to other growth factors either. Results showed that both LNCaP and PC-3 cells responded to prolactin with increased mAAT activity and an increased steady state level of mAAT mRNA. Prolactin also increased protein kinase C (PKC) activity in both these cell lines. Treatment of LNCaP and PC-3 cells with the phorbol ester 12-O-tetradecanoylphorbol (TPA) caused the same effect on mAAT activity and mRNA level as prolactin. The results suggest that the diacylglycerol-PKC signal transduction system mediates the prolactin effect on mAAT. In addition, these results also show that the prolactin effect on mAAT is independent of androgens since PC-3 cells reportedly lack androgen receptor expression. Thus, these results provide evidence that prolactin is a physiological regulator of prostate function in human as well as rat prostate. In addition, the results also show that though prostate cancer cells are androgen independent, they remain responsive to prolactin. This could have important implications for the treatment and management of prostate cancer.

Animals↗
PubMed1997

The genomic structure of a mouse seminal vesicle autoantigen.

The genomic structure of an androgen-stimulated mouse seminal vesicle autoantigen was determined. Analysis of the nucleotide sequence established 2135 bp of the 5'-flanking region, four exons of 123, 136, 112, 227 bp, three introns of 1555, 1931, 316 bp, and 185 bp of the 3'-flanking region of this gene. Ten DNA segments, five in the 5'-flanking region, two in the first intron, and three in the second intron were identified to have more than 50% homology with the consensus sequence of the androgen response element (ARE). Two sets of adjacent DNA segments, one including -213 to -199 bp and -124 to -110 bp in the 5'-flanking region and the other including 2532 to 2546 bp and 2582 to 2596 bp in the second intron, are noticeable for their high degree of homology with ARE.

Androgens↗
PubMed1997

A retrospective drug utilization evaluation of antihyperlipidaemic agents in a medical centre in Taiwan.

OBJECTIVE: The purpose of this study was to retrospectively evaluate the prescribing of antihyperlipidaemic agents in an 800-bed medical centre in southern Taiwan. METHODS: A retrospective study based on reviewing medical records was conducted using a computerized database. We randomly selected 344 patients (age range 5-85 years) who received an antihyperlipidaemic agent between 1 April 1994 and 30 September 1994 and reviewed their medical records. All the related data from the date when the antihyperlipidaemic agent was first prescribed to 31 December 1994 was assessed. Usage guidelines for antihyperlipidaemic agents were defined by referring to the literature and specialist opinion. RESULTS: Two hundred and twenty-two patients (64.5%) were treated with antihyperlipidaemic agents in accordance with the usage guidelines. In addition, most of the treatments complied with the regulations laid down by related health insurance programmes. The other 122 cases (35.5%) failed to meet any of the indications of the usage guidelines. Only 102 patients (29.7%) had their baseline lipid profiles examined and 117 patients (34%) had their baseline liver function tested. Over all, very few cases had lipid profiles and liver function tests every 3 months while taking antihyperlipidaemic agents. Patients who had been prescribed antihyperlipidaemic agents for more than 1 year were evaluated to assess the effectiveness of their pharmacological therapy. The prescribed doses were found to be lower than recommended in the general literature except for patients who received lovastatin and pravastatin. CONCLUSIONS: There are many treatment guidelines for hypercholesterolaemia in north America and Europe. This study revealed that a large proportion of antihyperlipidaemic agents used in our patient population did not comply with these general recommendations. Although the reasons for not complying with usage guidelines need to be further investigated, our study findings may well serve as the basis for further quality management and pharmacoeconomic analysis.

Adolescent↗
PubMed1997

Heterogeneity of the human H blood group alpha(1,2)fucosyltransferase gene among para-Bombay individuals.

BACKGROUND AND OBJECTIVES: The para-Bombay phenotype has a relatively high frequency of about 1 in 8,000 Taiwanese. Studies were carried out on eight healthy and unrelated Taiwanese with the para-Bombay phenotype to cast light on its immunogenetic basis. MATERIALS AND METHODS: Blood and saliva samples were tested with standard hemagglutination techniques. Salivary ABH substances were determined by hemagglutination inhibition. PCR techniques were used to amplify the coding region of the H genes. RESULTS: Five different h alleles, designated as h1, h2, h3, h4 and h5, were identified in the Taiwanese with the para-Bombay phenotype. The h1 allele loses one of the three AG repeats located at the nucleotides 547-552 of the H gene, whereas two of the three T repeats located at the nucleotides 880-882 are deleted in the h2 allele. The h3 allele contains a C658 to T missense mutation, whereas two missense mutations, C35 to T and A980 to C were identified in the h4 allele. A T460 to C missense is present in the h5 allele. The h5 allele was identified in an individual whose red blood cells contain blood group A antigen but not H antigen, and thus may be considered a weak variant of the H gene. CONCLUSIONS: So far no biologic relevance of the H antigen has been discovered, and its deficiency does not seem to produce any deleterious effects. There may be better understanding of the evolutionary basis for the polymorphisms at these loci after systematic study of different ethnic populations.

ABO Blood-Group System↗
PubMed1997

Three-dimensional surface reconstruction using optical flow for medical imaging.

The recovery of a three-dimensional (3-D) model from a sequence of two-dimensional (2-D) images is very useful in medical image analysis. Image sequences obtained from the relative motion between the object and the camera or the scanner contain more 3-D information than a single image. Methods to visualize the computed tomograms can be divided into two approaches: the surface rendering approach and the volume rendering approach. In this paper, a new surface rendering method using optical flow is proposed. Optical flow is the apparent motion in the image plane produced by the projection of the real 3-D motion onto 2-D image. The 3-D motion of an object can be recovered from the optical-flow field using additional constraints. By extracting the surface information from 3-D motion, it is possible to get an accurate 3-D model of the object. Both synthetic and real image sequences have been used to illustrate the feasibility of the proposed method. The experimental results suggest that the proposed method is suitable for the reconstruction of 3-D models from ultrasound medical images as well as other computed tomograms.

Algorithms↗
PubMed1997

Rapid polymerase chain reaction analysis of St14 (DXS52) VNTR: carrier detection of hemophilia A.

OBJECTIVE: To determine the frequency of St14 VNTR allele in Koreans as a marker of the hemophilia A and to evaluate the efficacy of this marker for carrier detection of hemophilia A METHODS: PCR amplified RFLP analysis of St14 VNTR was done in 312 X-chromosomes of 122 unrelated Korean males and 95 females and the same method was applied to carrier detection in the 2 hemophilia A families. RESULTS: There were 13 alleles of different sizes of St14 VNTR locus appeared in 312 X-chromosomes of unrelated Koreans. For carrier detection of hemophilia A, in the family A, the mother showed 1390/ 1330 bp alleles and the father showed 700 bp allele. The affected son has inherited 1390 bp allele from his mother. The daughter at risk showed 1330/700 bp alleles. In family B, the mother showed 1280/700 bp alleles and the stepfather showed 1390 bp allele. The affected son has inherited 1280 bp allele. The daughter at risk showed 1390/700 bp alleles. And so the daughters of the 2 families were not carriers for hemophilia A. CONCLUSION: PCR analysis of St14 VNTR was a useful tool for carrier detection of hemophilia A.

Alleles↗
PubMed1997

Identification and characterization of acoK, a regulatory gene of the Klebsiella pneumoniae acoABCD operon.

By using transposon insertional mutagenesis and deletion analyses, a recombinant clone containing the region upstream of the acoABCD operon of Klebsiella pneumoniae was found to be required for acetoin-inducible expression of the operon in Escherichia coli. The nucleotide sequence of the region was determined, and it displayed an open reading frame of 2,763 bp that is transcribed divergently to the acoABCD operon. This gene, designated acoK, is capable of encoding a protein with an overall 58.4% amino acid identity with MalT, the transcriptional activator of the E. coli maltose regulon. A conserved sequence for nucleotide binding at the N-terminal region, as well as a helix-turn-helix motif belonging to the LuxR family of transcriptional regulators at the C terminus, was also identified. Primer extension analysis identified two transcription initiation sites, S1 and S2, located 319 and 267 bp, respectively, upstream of the putative start codon of acoK. Several copies of NtrC recognition sequence [CAC-(N11 to N18)-GTG] were found in the promoter regions of both the acoK gene and the acoABCD operon. Acetoin-dependent expression of the acoABCD operon could be restored in the E. coli acoK mutants by supplying a plasmid carrying an intact acoK, suggesting a transactivating function of the gene product. The AcoK protein overproduced in E. coli was approximately 100 kDa, which is in good agreement with the molecular mass deduced from the nucleotide sequence. A specific DNA binding property and an ATPase activity of the purified AcoK were also demonstrated.

Acetoin↗