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Biomedical subjects

J Wu

Publications and source records attributed to J Wu.

At least 307 records · Page 17Linked to original sources
PubMed2001

In vitro maturation, fertilization and embryo development after ultrarapid freezing of immature human oocytes.

The purpose of this study was to determine the rates of maturation, fertilization and embryo development of ultrarapidly frozen immature oocytes (immature cumulus-oocyte complexes; COCs) obtained from antral follicles in ovaries of patients with chocolate ovarian cysts. The COCs were cryopreserved by a vitrification method using 5.5 mol ethylene glycol l (-1) plus 1.0 mol sucrose l (-1) in Dulbecco's PBS (DPBS). The survival, maturation and fertilization rates, and the percentage of embryos developing to the two-cell stage were 59, 64, 70 and 71%, respectively. No significant differences were noted in the rates of maturation, fertilization and embryo development between control and cryopreserved oocytes. Two embryos that developed from cryopreserved oocytes of the oocyte donor programme were selected for transfer into the uterus of a recipient with premature ovarian failure, after the recipient had received steroid replacement. A biochemical pregnancy occurred in the recipient after embryo transfer. These results indicate that immature oocytes can survive after cryopreservation and subsequently can be cultured to mature oocytes that are capable of undergoing fertilization in vitro and developing into embryos.

Adult↗
PubMed2001

Fate of atrazine and alachlor in redox-treated ferruginous smectite.

The oxidation state of structural iron (Fe) in clay minerals exerts a large influence on clay surface chemistry and may affect the adsorption and degradation of pesticides in the environment. This effect, however, has been little investigated. In the present study, herbicides atrazine and alachlor were reacted with ferruginous smectite (sample SWa-1) in its oxidized, reduced (either chemically or bacterially), and reduced-reoxidized states. In some experiments the herbicide was labeled with 14C. Gas chromatography/mass spectrometry (GC-MS) was also used to detect alachlor degradation products. Compared to oxidized clays, reduction by both chemical and microbial treatments decreased the concentration of both herbicides in the surrounding solution. Reoxidized clay exhibited behavior similar to the oxidized clay. Hydrolysis-dechlorination of atrazine occurred in the presence of chemically reduced SWa-1, and GC-MS analysis of alachlor revealed at least 14 degradation products after treatment with reduced clay and only two with the oxidized clay. Interaction of atrazine and alachlor with the clay may be through a H bond with the waters of hydration surrounding interlayer cations, the extent of which should increase with increasing acidity; but under reduced conditions, the validity of this model is unclear. Reduction of structural Fe may affect pH-dependent phenomena in two ways: The increased surface charge density increases the number of hydrated interlayer cations, thereby enhancing surface acidity, and increased electron density at basal surface oxygens increases their Brønsted basicity. Atrazine could, therefore, adsorb and/or degrade through either acid or alkaline hydrolysis pathways. Increased reduction potential of the reduced clay surfaces may also promote degradation.

Acetamides↗
PubMed2001

Cloning and sequence determination of a gene encoding an osmotin-like protein from strawberry (Fragaria X ananassa Duch.).

Osmotin and osmotin-like proteins (OLPs) are pathogenesis-related (PR) proteins, whose synthesis is normally stimulated upon infection of plants by pathogens. A strawberry genomic clone containing an osmotin-like protein (OLP) gene was isolated and sequenced. This clone contains an open reading frame of 681 nucleotides without any intron. The predicted amino acid sequence of the protein shares high degrees of homology with a number of other OLPs and related proteins, of which several are known to have antifungal activities. Southern hybridization analysis of strawberry genomic DNA suggested that the OLP is coded by a multi-gene family. Results from reverse transcriptase-polymerase chain reaction indicated that this OLP gene is expressed in uninfected strawberry plants.

Amino Acid Sequence↗
PubMed2001

Mycoplasma infections and different human carcinomas.

AIM: To explore relationships between human carcinomas and mycoplasma infection. METHODS: Monoclonal antibody PD4, which specifically recognizes a distinct protein from mycoplasma hyorhinis, was used to detect mycoplasma infection in different paraffin embedded carcinoma tissues with immunohistochemistry. PCR was applied to amplify the mycoplasma DNA from the positive samples for confirming immunohistochemistry. RESULTS: Fifty of 90 cases (56%) of gastric carcinoma were positive for mycoplasma hyorhinis. In other gastric diseases, the mycoplasma infection ratio was 28% (18/49) in chronic superficial gastritis, 30% (14/46) in gastric ulcer and 37% (18/49) in intestinal metaplasia. The difference is significant with gastric cancer (chi(2) = 12.06, P < 0.05). In colon carcinoma, the mycoplasma infection ratio was 55.1% (32/58),but it was 20.9% (10/49)in adenomarous polyp (chi(2)=13.46, P < 0.005). Gastric and colon cancers with high differentiation had a higher mycoplasma infection ratio than those with low differentiation (P < 0.05). Mycoplasma infection in esophageal cancer, lung cancer, breast cancer and glioma was 50.9% (27/53), 52.6% (31/59), 39.7% (25/63) and 41% (38/91), respectively. The mycoplasma DNA was successfully amplified with the DNA extracted from the cancer tissues that were positive for mycoplasma infection (detected with antibody PD4). CONCLUSION: There was high correlation between mycoplasma infection and different cancers, which suggests the possibility of an association between the two. The mechanism involved in oncogenesis by mycoplasma remains unknown.

Antibodies, Monoclonal↗
PubMed2001

Limitations in the use of ozone to disinfect maple sap.

The sap of the maple sugar tree (Acer saccharum) contains 2 to 3% sucrose and is traditionally collected early in the year and concentrated by boiling to produce maple syrup. High levels of microorganisms in the sap occur during holding, leading to a darker syrup with lower economic value. We investigated the use of dissolved ozone as a method to reduce the microbial population in sap. After 40 min of ozone treatment, concentrations of up to 0.30 mg/liter were achieved but were ineffective in reducing the aerobic plate count. Three predominant colonies on nutrient agar were selected for isolation and identification from sap. These included one mucoid and one nonmucoid yeast, both identified as Candida, and Pseudomonas fluorescens. When suspended in buffer, each was readily inactivated by ozone. Addition of 3% sucrose to the buffer markedly reduced the effectiveness of ozone. With the use of an ozone generator with a larger ozone output, saturating ozone concentrations (1 mg/liter) were achieved within 5 min but were accompanied by only a 1-log reduction in aerobic plate count of maple sap. After 40 min of ozone treatment, a less than 3-log reduction occurred. The results indicate that, because of the presence of sucrose, ozone may be of limited use in reducing the microbial population in sap.

Candida↗
PubMed2001

Opioids for chronic nonmalignant pain. Attitudes and practices of primary care physicians in the UCSF/Stanford Collaborative Research Network. University of California, San Francisco.

BACKGROUND: We hoped to determine the attitudes and practices of primary care physicians regarding the use of opioids to treat chronic nonmalignant pain (CNMP). We also examined the factors associated with the willingness to prescribe opioids for CNMP. METHODS: A survey was mailed to primary care physicians in the University of California, San Francisco/Stanford Collaborative Research Network. This survey contained questions regarding treatment in response to 3 case vignettes, the use of opioids for CNMP in general, and the demographic characteristics of the physicians. RESULTS: Among 230 physicians surveyed, 161 (70%) responded. Two percent of the respondents were never willing to prescribe schedule III opioids (eg, acetaminophen with codeine) as needed for patients with CNMP that persisted unchanged after exhaustive evaluation and attempts at treatment. Thirty-five percent were never willing to prescribe schedule II opioids (eg, sustained-release morphine) on an around-the-clock schedule for these patients. The most significant predictor of willingness to prescribe opioids for patients with CNMP was a lower level of concern about physical dependence, tolerance, and addiction. CONCLUSIONS: Primary care physicians are willing to prescribe schedule III opioids as needed, but many are unwilling to use schedule II opioids around the clock for CNMP. Individual prescribing practices vary widely among primary care physicians. Concerns about physical dependence, tolerance, and addiction are barriers to the prescription of opioids by primary care physicians for patients with CNMP.

Adolescent↗
PubMed2001

[Effects of high temperature and cigarette smoke on the development of nervous system in early rat embryos].

In order to explore the effect of high temperature or cigarette smoke and their combined effect on the development of nervous system in early rat embryos, pregnant rats at the 8-11th day of gestation were exposed to high temperature and water soluble substances of cigarette smoke. All indexed of embryonic nervous system development were determined with experimental treat logical methods. The results showed that following the increase of temperature or cigarette smoke exposure all indexes correlated with embryonic nervous system development and morphological differentiation were changed, with an apparent dose-effect relationship (P < 0.01). The changes were related to specific phase of embryonic development. The results showed also that the nervous system development and morphological differentiation induced by both high temperature and cigarette smoke were higher than that by any single factor.

Animals↗
PubMed2001

[Polymorphisms of the CYP1A1 and GSTM1 genes and their combined effects on individual susceptibility to lung cancer in a Chinese population].

OBJECTIVE: To investigate the polymorphisms of CYP1A1 and GSTM1 genes as well as their separate and combined effects on individual susceptibility to lung cancer. METHODS: In the matched 106 pairs of patients with lung cancer and non-cancer control persons, genomic DNA were prepared from peripheral blood samples. The genotypes of CYP1A1 Ile/Val and GSTM1+/0 polymorphisms were detected by the allele-specific(AS)-PCR and multidifferential(MD)-PCR. RESULTS: Individuals with genotype Val/Val of CYP1A1, genotype 0/0 of GSTM1, combined genotypes GSTM1 0/0 and CYP1A1 Val/Val, or combined genotypes GSM1 0/0 and CYP1A1 Ile/Val had higher relative risk than those with the corresponding common genotypes and combined genotypes; their odds ratios were 4.02(P=0.03), 1.92(P=0.019), 9.38(P=0.04) and 3.27(P=0.01), respectively. CONCLUSION: There is a synergy of susceptible genotypes GSTM1 0/0 and CYP1A1 Val/Val or CYP1A1 Ile/Val to enhance the individual susceptibility to lung cancer.

Adult↗
PubMed2001

[Cloning, expression and preliminary application of a alpha-hydroxynitrile lyase from cassave].

alpha-Hydroxynitrile lyase (ME-HNLs, E.C. 4.1.2.3.37) from the cyanogenic crop cassava(Manihot esculentz, Crantz) catalyze the condensation of hydrocyanic acid and aldehydes or ketone into (s)-cyanohydrins, which are valuable starting material for various optically active compounds, such as pharmaceuticals and agrochemicals. The cDNA of a ME-HNL were obtained by RT-PCR and cloned. The sequencing result for the cDNA showed that the sequence encoded for the ME-HNL was inconsistent with all those which are published, such as hnl10, hnl24, hnl4. The full sequence analysis demonstrated that the cloned cDNA was about 75.2%, 79.8%, 99.2% homologous to other three reported HNL genes from cassava, respectively, among which the last was the same to the cloned gene except the five base substitution at the site 142, 337, 476, 634 and 636, respectively. The two base substitutions lead to change the amino acid sequence, i.e., Ser113-->Gly113, Phe158-->Tyr158. To construct the recombinant plasmid pET30a-hnl, the cDNA was inserted into an expression vector pET30a. After transformation of pET30a-hnl and induction with IPTG, the ME-HNL was efficiently expressed in E. coli. BL21 (DE3) and reached over 2100 units/L of culture with the specific activity 8.5 u/mg protein. By one simple treatment, incubating 10 minutes at 70 degrees C, the recombinant ME-HNL may be used as an catalyst for production of (S)-mandelonitrile with enantiomeric excess of 95.2% and 98.2% yield.

Aldehyde-Lyases↗
PubMed2001

Effects of moxa-cone moxibustion at Guanyuan on erythrocytic immunity and its regulative function in tumor-bearing mice.

In the sarcoma S180 ascitic mice, the effects of moxa-cone moxibustion at Guanyuan (CV 4) on erythrocytic immunity and its regulative function were investigated. The results indicated that moxibustion at Guanyuan (CV 4) could significantly increase the decreased erythrocytic C3b receptor rosette forming rate (RBC-C3bRR), lower the raised erythrocytic immunocomplex rosette forming rate (RBC-ICR, P < 0.05 or P < 0.01), increase the decreased activity of erythrocytic immuno-accelerative factor, and reduce the increased activity of erythrocytic immunosuppressive factor (P < 0.05) in the tumor-bearing mice. This suggests that moxibustion at Guanyuan (CV 4) can strengthen erythrocytic immunity and promote its regulative function.

Acupuncture Points↗
PubMed2001

p53 mutation in plasma DNA and its prognostic value in breast cancer patients.

PURPOSE: Tumor-specific DNA has recently been detected in the plasma of lung, head and neck, breast, and colon cancer patients. Detection of tumor-specific genetic materials in cancer patients at sites distant from the tumor, such as in the blood, may provide a unique and valuable tumor marker for diagnosis and prognosis. EXPERIMENTAL DESIGN: The present investigation was aimed at determining the presence of p53 mutations in the peripheral blood of breast cancer patients and its prognostic value in these patients. RESULTS: In this study, we found that the mean concentration of plasma DNA in healthy women was 21 ng/ml, whereas in patients with breast cancer the mean concentration was 211 ng/ml (P < 0.01). p53 mutations were detected in the primary tumors of 46 of 126 (36.5%) breast cancer patients. Of these 46 patients, 30 (65.1%) were found to have p53 mutations in their plasma DNA. p53 mutations in plasma DNA were strongly correlated with clinical stage, tumor size, lymph node (LN) metastasis, and estrogen receptor status (P < 0.05). After a median follow-up of 29 months, univariate and multivariate analysis revealed that both primary tumor and plasma DNA p53 mutations were significant prognostic factors for both relapse-free and overall survival. Furthermore, we demonstrated that patients with both primary tumor and plasma p53 mutations have the worst survival. This outcome occurs in both LN-positive and LN-negative groups. Thirteen of the 22 (59%) patients with recurrence and/or metastasis later had detectable p53 mutations in their plasma DNA. CONCLUSIONS: Detection of p53 mutations in plasma DNA may be used as a prognostic factor and an early marker to indicate recurrence or distant metastasis.

Adult↗
PubMed2001

[Clinical study on hepatitis D virus-positive patients died from severe hepatitis B].

OBJECTIVE: To investigate the role of hepatitis D virus (HDV) in the development of severe hepatitis B. METHODS: Seventy-six HDV-positive patients died from severe hepatitis B were compared with 244 HDV-negative patients from severe hepatitis B in clinical manifestations, signs, complications and main biochemical indexes at the same period. RESULTS: HDV-positive patients had obvious ascites, abdominal distension, digestive tract hemorrhage as compared with the HDV-negative ones (P<0.05). There were significant differences in hepatorenal syndrome, bacterial infection, manifold complications, the levels of total bilirubin and alanine aminotransferase, and the activity of prothrombin between the patients of the two groups (P<0.01). CONCLUSIONS: HDV can aggravate severe hepatitis B.

Adolescent↗
PubMed2001

[Cloning and expression of maltooligosyltrehalose synthase from Sulfolobus acidocaldarius in Escherichia coli].

The gene of MTSase (maltooligosyltrehalose synthase) from Sulfolobus acidocaldarius ATCC49426 was amplified by PCR. The primers were designed according to the published sequence of homologous gene from Sulfolobus acidocaldarius ATCC33909. This gene was inserted into the plasmid pBV220 and the resultant recombinant plasmid pBV220-GT was transformed to E. coli DH5 alpha. The activity of recombinant enzyme was about 10 u/g(wet cell). In order to improve the expression level of target protein, some nucleotides in the 3' and 5' of the gene were modified to optimize the second structure of mRNA by PCR amplification using the new primers devised according to the biosoftware GOLDKEY2.0. As a result, the activity of recombinant enzyme increase to 19.8 u/g(wet cell). Then, the helping plasmid pUBS520 which carried the gene encoding the tRNA of rare codons AGG and AGA was transformed to the recombinant strain. But it took little effect.

Cloning, Molecular↗
PubMed2001

[Allele sequences and population genetics of pentanucleotide tandem repeat D6S957].

OBJECTIVE: Pentanucleotide tandem repeat loci are useful markers of short tandem repeat (STR) for genetic analysis. We focused on the analysis of the DNA sequence for each allele at the pentanucleotide STR locus D6S957 in order to understand their structures in the human genome and to construct human allelic ladder, which is necessary for forensic DNA typing. In order to evaluate the forensic applicability of D6S957, we investigated the genotype distributions and allele frequencies in major ethnic groups. METHODS: A total of 230 samples from unrelated individuals were analyzed by PCR. Allele determination was carried out by comparison with a sequenced human allelic ladder made in-house. An example of each allele was sequenced on an ABI 377 automated sequencer. RESULTS: This pentanucleotide STR exhibited a minimal amount of stutter and provided easily interpretable results. Eight alleles were found in these populations. No evidence of deviation from Hardy-Weinberg equilibrium was observed. In 64 confirmed father/mother/child triplets no mutation events were observed. The mutation rate was indirectly estimated at 2.5 x 10(-5) using a maximum likelihood method. CONCLUSION: D6S957 is a useful marker for forensic casework and paternity analysis.

Alleles↗
PubMed2001

[Studies on asymmetric synthesis of R-phenylethanolamine by whole cells of Arachnia sp. P163].

Effects of various factors on asymmetric synthesis of R-phenylaminoethanol from aminoacetophenone by the whole cells of Arachnia sp. P163 producing alcohol dehydrogenase for phenylethanol amine was investigated. It found that, although the reduction was inhibited by the substrate and the product, but it has the very high stereoselectivity. The reduction was normaly carried out with 2% glucose for reproduction of coenzyme in the reaction system without oxygen. The conversion yield and ee value of the product achieved 65% and 100%, respectively.

2-Hydroxyphenethylamine↗