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Biomedical subjects

H Wang

Publications and source records attributed to H Wang.

At least 757 records · Page 42Linked to original sources
PubMed2000

Molecular characterization of a PDI-related gene prpA in Aspergillus niger var. awamori.

A gene (prpA) homologous to the protein disulfide isomerase gene was isolated from Aspergillus niger by Southern hybridization using the pdi1 gene isolated from Trichoderma reesei as a DNA probe. The corresponding cDNA of the prpA gene has also been isolated from an A. niger var. awamori cDNA library. The prpA gene does not belong to any currently recognized family of protein disulfide isomerases since it contains only a single conserved thioredoxin domain at the N-terminus of the protein. The C-terminal two-thirds of the protein has no homology to any known proteins in the database. The PRPA protein contains an ER retention signal (HDEL) at its C-terminal end suggesting that it is located in the ER. Southern hybridization at high stringency showed that it was present as a single copy in the genome. Northern hybridization indicated that the transcript level of the prpA gene was higher if the cells were secreting a heterologous protein, bovine prochymosin. However, over-expression of the prpA gene from a multicopy integrated vector had little effect on chymosin secretion. A strain containing a deletion of the prpA gene was viable. However, deletion of the prpA gene appeared to cause a reduction of bovine chymosin production.

Amino Acid Sequence↗
PubMed2000

SM5-1: a new monoclonal antibody which is highly sensitive and specific for melanocytic lesions.

Antibodies such as HMB-45 and anti-S100 protein have been widely used as markers of malignant melanoma despite evidence that HMB-45 has a sensitivity of only 67-93% and S100 is nonspecific for melanoma. Using a subtractive immunization protocol in a mouse model of human melanoma, we have generated several monoclonal antibodies with putative specificity for melanoma. After initial screenings, the antibody SM5-1 was chosen because of its intriguing reactivity with melanocytic tumors in both frozen and paraffin sections. The immunohistochemical staining of SM5-1 was studied in paraffin-embedded specimens of 401 melanomas (n = 401; 250 primary melanomas, 151 metastases), melanocytic nevi of the skin (n = 16), nonmelanocytic neoplasms (n = 84). The results were compared with HMB-45 and anti-S100 staining. All antibodies reacted with nevi and 97-99% with primary melanomas. Whereas both SM5-1 and anti-S100 stained 96% (146/151) of melanoma metastases, HMB-45 correctly identified only 83% (126/151). All HMB-45-negative metastases were positive for SM5-1. Whereas neither SM5-1 nor HMB-45 stained any of 84 specimens from 40 different nonmelanocytic neoplasms, anti-S100 was positive in 21/84 (25%). While the staining pattern of SM5-1 was mostly homogeneous, small tumor areas in some metastases remained unstained. Staining with SM5-1 was also observed in perivascular dendritic cells, in plasma cells, some myofibroblasts and the secretion of eccrine sweat glands. Nonactivated epidermal melanocytes, keratinocytes, endothelial cells, smooth muscle cells and peripheral nerves were all negative for SM5-1. These results suggest that SM5-1 is highly specific, as well as sensitive, for melanocytic lesions and is useful in the immunohistochemical evaluation of melanoma.

Animals↗
PubMed2000

Application of Live Monocells from Macroalgae to Shellfish Seed Production.

Monocells were isolated from several macroalgae, Porphyra yezoensis, Undaria pinnatifida, and Laminaria japonica, by digestion with alga-tool enzymes. The monocells were then used to feed the parents or larvae of bay scallop Argopecten irradians, blood cockle Arca inflata, and abalone Haliotis discus juveniles. Results showed that the parents of bay scallop and blood cockle fed with Porphyra monocells could mature and discharge eggs and spermatozoa and their larvae could metamorphose; the survival rate of abalone juveniles fed with isolated cells from Laminaria and Undaria increased by 100% compared with that of those fed with artificial food.

Journal Article↗
PubMed2000

In vitro activity of meropenem and four other antibiotics against 554 clinical strains obtained from Beijing in 1999.

In 1999, a surveillance study was initiated in a hospital in Beijing to monitor the potency and spectrum of five extended-spectrum beta-lactam antimicrobial agents (meropenem, imipenem, cefepime, ceftazidime, and cefoperazone/sulbactam) tested against 554 strains of bacteria. Five groups of organisms were tested by the E-test method, with results validated by concurrent quality control strain analysis. Results were tabulated, and 100% of quality assurance tests (16/16 tests) were within ranges recommended by the National Committee for Clinical Laboratory Standards. Of the five beta-lactam drugs tested, meropenem and imipenem were the most active against all isolates tested. Overall, the rank order of activity of the five agents was: meropenem (94.6% susceptible) > imipenem (90.1%) > cefepime (77.6%), cefoperazone/sulbactam (77.5%), ceftazidime (76.6%). Ninety-five percent of Enterobacter were to meropenem, while 82% were susceptible to imipenem. Meropenem was more active than imipenem against Pseudomonas aeruginosa. The minimum inhibitory concentration (MIC) of meropenem was eightfold lower than that of imipenem. Meropenem had excellent activity against Haemophilus influenzae, Streptococcus pneumoniae, and oxacillin-susceptible staphylococci.

Anti-Bacterial Agents↗
PubMed2000

The mechanochemistry of V-ATPase proton pumps.

The vacuolar H(+)-ATPases (V-ATPases) are a universal class of proton pumps that are structurally similar to the F-ATPases. Both protein families are characterized by a membrane-bound segment (V(o), F(o)) responsible for the translocation of protons, and a soluble portion, (V(1), F(1)), which supplies the energy for translocation by hydrolyzing ATP. Here we present a mechanochemical model for the functioning of the V(o) ion pump that is consistent with the known structural features and biochemistry. The model reproduces a variety of experimental measurements of performance and provides a unified view of the many mechanisms of intracellular pH regulation.

Adenosine Triphosphate↗
PubMed2000

Decreased in vitro fertilization and cleavage rates after an equipment error during CO(2) calibration.

OBJECTIVE: To report the decreased IVF rate of oocytes and the reduced cleavage rate of pronuclear stage embryos after gas has backflowed from a gas analyzer into an incubator during the calibration of the CO(2) concentration. DESIGN: Case report. SETTING: Clinical research unit for reproductive medicine in a hospital. INTERVENTION(S): Backflow of gas from a gas analyzer into an incubator during calibration of the CO(2) concentration. MAIN OUTCOME MEASURE: The IVF rate of oocytes and the cleavage rate of pronuclear stage embryos. RESULT(S): Thirty-two oocytes were retrieved from four infertile female patients. Nine oocytes were fertilized and four fertilized oocytes were cleaved. In a related animal experiment, the cleavage rate was 57.1% (36/63) in the control group and 25.4% (16/63) in the study group (P =.00026). CONCLUSION(S): The backflow of gas from the gas analyzer adversely affected the fertilization of oocytes and the cleavage of pronuclear stage embryos.

Animals↗
PubMed2000

Mutation analysis of the growth differentiation factor-9 and -9B genes in patients with premature ovarian failure and polycystic ovary syndrome.

OBJECTIVES: To investigate whether growth differentiation factor (GDF)-9 or GDF-9B/bone morphogenetic protein (BMP)-15 mutation is present in Japanese women with premature ovarian failure (POF) and polycystic ovary syndrome (PCOS). DESIGN: Clinical and molecular studies. SETTING: Outpatient clinic in a university hospital. PATIENT(S): Fifteen women with POF, 38 women with PCOS, and 3 normal fertile controls. INTERVENTION(S): Extraction of DNA from blood samples for subsequent polymerase chain reaction (PCR). MAIN OUTCOME MEASURE(S): Amplified DNA was analyzed by denaturing gradient gel electrophoresis (DGGE) and/or by direct sequencing. RESULT(S): No missense mutation was found in any exons of the GDF-9 gene and the GDF-9B/BMP-15 gene in patients with POF and PCOS. CONCLUSION(S): The missense mutation in the GDF-9 gene or the GDF-9B/BMP-15 gene is uncommon in anovulatory Japanese women with POF and PCOS.

Adult↗
PubMed2000

On-line characterization of the activity and reaction kinetics of immobilized enzyme by high-performance frontal analysis.

A microreactor by immobilized trypsin on the activated glycidyl methacrylate-modified cellulose membrane packed column was constructed. Immobilized trypsin mirrored the properties of the free enzyme and showed high stability. A novel method to characterize the activity and reaction kinetics of the immobilized enzyme has been developed based on the frontal analysis of enzymatic reaction products, which was performed by the on-line monitoring of the absorption at 410 nm of p-nitroaniline from the hydrolysis of N-alpha-benzoyl-DL-arginine-p-nitroanilide (BAPNA). The hydrolytic activity of the immobilized enzyme was 55.6% of free trypsin. The apparent Michaelis-Menten kinetics constant (Km) and Vmax values measured by the frontal analysis method were, respectively, 0.12 mM and 0.079 mM min(-1) mg enzyme(-1). The former is very close to that observed by the static and off-line detection methods, but the latter is about 15% higher than that of the static method. Inhibition of the immobilized trypsin by addition of benzamidine into substrate solution has been studied by the frontal analysis method. The apparent Michaelis-Menten constant of BAPNA (Km), the inhibition constant of benzamidine (Ki) and Vmax were determined. It was indicated that the interaction of BAPNA and benzamidine with trypsin is competitive, the Km value was affected but the Vmax was unaffected by the benzamidine concentration.

Enzymes, Immobilized↗
PubMed2000

Quality of life for children with fecal incontinence after surgically corrected anorectal malformation.

PURPOSE: The aim of this study was to investigate influences of fecal incontinence on children's quality of life after surgically corrected anorectal malformation. METHODS: Seventy-one children with anorectal malformation underwent follow-up for 8 to 16 years postoperatively. They were divided into good, fair, and poor groups by assessment of anal function. The quality of life was investigated by self-structured disease impact questionnaires and Achenbach's Child Behavior Check List (CBCL). A quality-of-life scoring criteria was established to assess quality of life of the 71 children with operated anorectal malformation and controls. RESULTS: Owing to fecal incontinence, 12 (16.9%) children reported that there were problems in peer relationships; school absences happened in 13 (18.3%) children; 17 (23.9%) children had to restrict themselves to certain food. Based on CBCL, 13 (18.3%) children had behavior problems. The behavior problems in children with poor fecal continence (66.7%) were significantly higher than those of children with good fecal continence (8.6%). According to the quality-of-life scoring criteria, the scores of children with operated anorectal malformation (9.4+/-3.7) were significantly lower than those of the controls (11.2+/-0.9). The scores of children with poor fecal continence (4.8+/-1.4) were significantly lower than those of children with good fecal continence (10.9+/-1.2). CONCLUSIONS: The children with poor fecal continence have poor quality of life caused by fecal dysfunction. Attention should be paid to the rehabilitation of fecal continence after surgery, such as bowel training and biofeedback therapy. The somatic and psychological care and long-term follow-up are necessary to improve the quality of life.

Adolescent↗
PubMed2000

The nitration of pyrene adsorbed on silica particles by nitrogen dioxide.

Conversion of NO2, HNO2 gas, their mixture and a mixed gas of HNO2 and HNO3 on silica particles was investigated under simulated atmospheric conditions. Both HNO2 and HNO3 were detected as the products from conversion of NO2 on silica particles. However, unlike HNO3, which increased with conversion time, HNO2 underwent an increase-decrease time course due to the increased HNO3 further transformed HNO2 into NO+ on silica particles. Considering the catalytic effect of HNO3 and HNO2 on the nitration of pyrene adsorbed on silica particles by NO2, another electrophilic nitration path, analogous to the one that we previously reported, with NONO2+ and NON2O4+ as electrophiles was suggested. The two paths together gave an appropriate explanation for the catalytic effect of HNO2, HNO3 and their mixed gas on the nitration of the adsorbed pyrene by NO2.

Adsorption↗
PubMed2000

Retrovirally mediated delivery of angiotensin II type 1 receptor antisense in vitro and in vivo.

In spite of excellent drugs that are available for the control of hypertension, the pharmacological approach has major disadvantages including compliance, side effects, and inability to cure the disease. In the present chapter we provide evidence that a gene therapy concept based on the inhibition of the RAS at a genetic level, with the use of an antisense to the AT1R, is an exciting and viable approach for long-term control of hypertension without the disadvantages inherent in pharmaceutical therapy. A retrovirus-based vector has been used to deliver AT1R-AS in Ang II target tissues both in vitro and in vivo. The transduction efficiency is high and leads to the attenuation of Ang II action in vitro and prevention of hypertension in the SH rat, a model for primary human hypertension. These studies have unveiled a new avenue in which a similar approach could be attempted in the reversal of hypertension in adult animals.

Animals↗
PubMed2000

The French neurotropic vaccine strain of yellow fever virus accumulates mutations slowly during passage in cell culture.

This study of the yellow fever French neurotropic vaccine strain from the Institut Pasteur (FNV-IP) demonstrates that this viral genome is not as stable as that of the 17D-204 vaccine virus. FNV-IP was plaque-purified three times and then passaged eight times in Vero cells. Viral populations from the second and eighth passage post purification were sequenced and compared to the published sequences of FNV-IP. The passage-2 viral population had 31 nucleotide and nine amino acid changes compared to the parental virus while the passage-8 virus had six additional nucleotide changes encoding a single amino acid substitution. The plaque-purified virus also had two sequence deletions in the 3'-noncoding region. The plaque purification resulted in selection of a passage-2 virus that had a mouse LD(50) of 20 pfu/ml, 67-fold greater than parental FNV-IP which had an LD(50) of 0.3 pfu/ml. Subsequent passage in Vero cells resulted in a passage-8 virus which had increased neurovirulence with an LD(50) of 3.2 pfu/ml. The only amino acid difference between the passage-2 and passage-8 viruses was at amino acid 638 of NS5 which lies within domain V of the RNA-dependent-RNA polymerase. Overall, these data indicate that FNV-IP virus has an inherently less stable genome than 17D vaccine virus and a variable viral population.

Amino Acid Sequence↗
PubMed2000

Roles for ephrins in positionally selective synaptogenesis between motor neurons and muscle fibers.

Motor axons form topographic maps on muscles: rostral motor pools innervate rostral muscles, and rostral portions of motor pools innervate rostral fibers within their targets. Here, we implicate A subfamily ephrins in this topographic mapping. First, developing muscles express all five of the ephrin-A genes. Second, rostrally and caudally derived motor axons differ in sensitivity to outgrowth inhibition by ephrin-A5. Third, the topographic map of motor axons on the gluteus muscle is degraded in transgenic mice that overexpress ephrin-A5 in muscles. Fourth, topographic mapping is impaired in muscles of mutant mice lacking ephrin-A2 plus ephrin-A5. Thus, ephrins mediate or modulate positionally selective synapse formation. In addition, the rostrocaudal position of at least one motor pool is altered in ephrin-A5 mutant mice, indicating that ephrins affect nerve-muscle matching by intraspinal as well as intramuscular mechanisms.

Animals↗
PubMed2000

Cyclooxygenase active bioflavonoids from Balaton tart cherry and their structure activity relationships.

Several flavonoids and isoflavonoids isolated from Balaton tart cherry were assayed for prostaglandin H endoperoxide synthase (PGHS-1) enzyme or cyclooxygenase isoform-1 (COX-1) activity. Genistein showed the highest COX-1 inhibitory activity among the isoflavonoids studied, with an IC50 value of 80 microM. Kaempferol gave the highest COX-1 inhibitory activity among the flavonoids tested, with an IC50 value of 180 microM. The structure-activity relationships of flavonoids and isoflavonoids revealed that hydroxyl groups at C4', C5 and C7 in isoflavonoids were essential for appreciable COX-1 inhibitory activity. Also, the C2-C3 double bond in flavonoids is important for COX-1 inhibitory activity. However, a hydroxyl group at the position decreased COX-1 inhibitory activity by flavonoids.

Cyclooxygenase 1↗
PubMed2000

Enzyme biosensor for studying therapeutics of Alzheimer's disease.

An electrochemical method for the investigation and comparison of anti-Alzheimer medications that is based on the inhibition of the acetylcholinesterase is presented. The developed amperometric biosensor determines the in-vitro inhibition of the acetylcholinesterase that is co-immobilized with choline oxidase on the working electrode surface of a three-electrode system using gel entrapment. The sensor has been applied to determine the IC50 values of two known and one newly developed Alzheimer remedy. A simultaneous measurement with the photometric standard method shows the applicability of our method for fast drug screening.

Acetylcholinesterase↗