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Biomedical subjects

C Wang

Publications and source records attributed to C Wang.

At least 1,477 records · Page 82Linked to original sources
PubMedDate not supplied

Genetic relationships of infectious bronchitis virus isolates from Mississippi broilers.

A 582-base pair segment located in the nucleocapsid protein terminal part of the S1 gene of 26 Arkansas (Ark)-type infectious bronchitis virus (IBV) isolates from Mississippi broilers was amplified and sequenced. Reverse transcription-polymerase chain reaction and cycle sequencing techniques were used to elucidate the genetic and deduced amino acid relationships among the isolates. Analysis suggested that the nucleotide and amino acid sequences of the isolates were highly conserved, with greater than 99.4% nucleotide and 98.4% amino acid homology among the Mississippi isolates. The Mississippi isolates had less than 2.3% nucleotide and 5.2% amino acid variation when compared with the vaccine strain Ark DPI and less than 3.0% nucleotide and 5.2% amino acid variation when compared with the Ark-type Georgia variant. This study suggests that the 26 IBV isolates that are genetically closely related to the vaccine strain may be derived from the vaccine strain by point mutation. The results also indicate that within a 1-yr period Ark-type IBV in Mississippi was spread with little or no change in its genetic sequence. The 21 identical isolates appeared in different farms and companies, suggesting that poor biosecurity was practiced and contributed to the spreading of the disease.

Amino Acid Sequence↗
PubMedDate not supplied

A comparative study of immunochemical fecal tests for detection of colorectal adenomatous polyps.

BACKGROUND/AIMS: This study was conducted to assess the diagnostic validity of new different immunochemical fecal occult blood tests for colorectal adenomatous polyps, including reversed passive hemagglutination test (Immudia-HemSp), combination monoclonal antibody guaiac test (Monohaem), latex agglutination inhibition test (Iatro Hemcheck), and latex agglutination tests (LA Hemochaser, OC-Hemodia). METHODOLOGY: Two hundred and fifty patients with colorectal adenomatous polyps 1.0 cm or larger in diameter and the same number of healthy controls served as subjects for the study. Each subject received a set of 5 immunochemical tests within 3 consecutive days, and sensitivities and specificities of these tests were evaluated. RESULTS: Mean sensitivity and specificity in a set of 5 immunochemical tests were 47.6% and 95.8%, respectively. Sensitivities and specificities of 5 different immunochemical tests were calculated as 47.6% and 96.8% for Immudia-Hem Sp, 46.8% and 95.2% for Monohem, 46.4% and 95.2% for Iatro Hemchek, 48.0% and 96.4% for LA Hemochaser, and 49.2% and 95.6% for OC-Hemodia, respectively, showing no significant difference in sensitivity and specificity among the 5 tests. CONCLUSIONS: These findings suggest that there is no difference in the degree of accuracy for colorectal adenomatous polyps among several types of immunochemical fecal occult blood test.

Adenomatous Polyposis Coli↗
PubMedDate not supplied

Posttesticular antifertility action of triptolide in the male rat: evidence for severe impairment of cauda epididymal sperm ultrastructure.

A variety of active diterpene epoxides, including the triptolide (isolated from Tripterygium wilfordii) have been reported to cause infertility in male rats. Previously, we showed that oral administration of triptolide at a dosage of 100 microg/kg per body weight for 70 days completely inhibited fertility in male rats, with little or no demonstrable detrimental effect on spermatogenesis and Leydig cell function as determined by testicular light microscopic appearance and serum and intratesticular testosterone levels. Despite the apparent absence of effects on the testes, cauda epididymal sperm were abnormal, with complete cessation of sperm motility and some reduction in sperm numbers. This study was undertaken to provide additional insight into the subcellular sites and possible mechanisms of action of this compound using ultrastructural analysis of the testes and epididymidis. The most striking effect of triptolide treatment was observed in sperm in the epididymis. In rats rendered infertile with 100 microg/kg per body weight of triptolide daily for 70 days, virtually all cauda epididymal sperm exhibited complete absence of plasma membrane over the entire middle and principal piece, premature decondensation of the nuclei, and disorganization of the mitochondrial sheath with many vacuolated mitochondria. No ultrastructural differences in the epididymal epithelium were observed between control and triptolide-treated rats. The testes appeared to be mildly affected after triptolide treatment but exhibited only subtle ultrastructural defects in the germ cells. The findings of severe impairment of cauda epididymal sperm ultrastructure, along with minimal discernible abnormalities in the fine structural cytology of the testes, further suggest that the site of action of this compound is posttesticular and may be confined to the cauda epididymal sperm. However, we cannot rule out an effect of triptolide that occurs during germ cell maturation but is delayed in its manifestation or triggered at the rete testis and epididymal level.

Animals↗
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Analysis of multivariables during porcine liver digestion to improve hepatocyte yield and viability for use in bioartificial liver support systems.

In order to achieve optimal BALSS function, preparation of porcine hepatocytes with high yield, viability, and P450 activity is known to be important. To date hepatocyte yields have varied from 0.58 x 10(10) to 3.45 x 10(10) and viabilities from 75% to 95% within and between laboratories, even when using the same digestion methods and procedures, indicating that hepatocyte isolation during porcine liver digestion is not fully optimized. The aim of this work was to identify the critical parameters affecting cell recovery during porcine liver harvesting by investigating 21 variables involved in the process, including pig body and liver weight, different digestion times of perfusates, pH, a range of concentrations of sodium and chloride in EDTA, and collagenase perfusates. Univariate and multivariate analysis of a retrospective study (n = 23) revealed that low perfusate pH during the process of digestion had a positive effect on hepatocyte yield (p < 0.05), while high (relative) concentrations of sodium and chloride in the perfusates had significant negative effects on hepatocyte viability (both p < 0.05). Sodium and chloride had narrow optimal ranges for achieving a >90% viability. These findings were then tested in a prospective study (n = 10) and further verified. High hepatocyte viabilities (91.8+/-1.6% p = 0.036) and yields (2.56+/-0.48 x 10(10)) were achieved consistently, and P450IA1 activity was increased after sodium and chloride concentrations and pH in the perfusates were controlled. The physiological mechanism by which sodium and chloride affects hepatocyte viability during porcine liver digestion is discussed.

Animals↗
PubMedDate not supplied

Long-term effects of triptolide on spermatogenesis, epididymal sperm function, and fertility in male rats.

Prior studies had suggested that triptolide, a diterpene triepoxide isolated from a Chinese medicinal plant, might be an attractive candidate as a post-testicular male contraceptive agent. Despite the promise that triptolide would not affect testis function, nagging concerns remained that a delayed onset of testicular effect might exist. The objectives of this study were to assess the effects of relatively longer treatment duration of triptolide on fertility, spermatogenesis, and epididymal sperm pathophysiology; and to evaluate the reversibility of these effects after the cessation of treatment. Adult male Sprague-Dawley rats were fed daily with either 30% gum acacia as a vehicle control (n = 12) or 100 microg/kg body weight (BW) of triptolide for 82 days (n = 12) followed by a recovery period of up to 14 weeks (n = 6). At the end of the treatment period, all rats treated with triptolide were sterile. Cauda epididymal sperm content decreased by 84.8% and sperm motility was reduced to zero. In addition, virtually all cauda epididymal sperm in the triptolide-treated group exhibited severe structural abnormalities. The most striking changes observed were head-tail separation, premature chromatin decondensation of sperm nuclei, a complete absence of the plasma membrane of the entire middle and principle pieces, disorganization of the mitochondrial sheath, and aggregation of many sperm tails. Longer treatment duration of triptolide also affected spermatogenesis, with marked variability in the response of individual animals. The degree of damage ranged from apparently normal-looking seminiferous tubules to flattened seminiferous epithelium lined by a single layer of cells consisting of Sertoli cells and a few spermatogonia. Affected tubules exhibited intraepithelial vacuoles of varying sizes, multinucleated giant cells, germ cell exfoliation, and tubular atrophy. Recovery occurred as early as 6 weeks after cessation of treatment. By 14 weeks, 4 out of 6 triptolide-treated males were fertile and the females that were impregnated by 3 out of 4 triptolide-treated male rats produced apparently normal litters. These results suggest that triptolide has 2 phenotypic effects on mature and maturing germ cells. The first action appears earlier and manifests mainly in epididymal sperm. The second action presumably is directly on germ cells in testis and causes a variable impairment of spermatogenesis that may not be completely reversible. It is unclear if the earlier effect is a delayed manifestation of subtle testicular injury or post-testicular action.

Animals↗
PubMedDate not supplied

In vitro susceptibility of avian mycoplasmas to enrofloxacin, sarafloxacin, tylosin, and oxytetracycline.

In vitro susceptibility of avian Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) to enrofloxacin, sarafloxacin, tylosin, and oxytetracycline was determined by a serial broth dilution method. The minimum inhibitory concentration (MIC) was recognized by a conversion of the pH indicator phenol red in culture media to a yellow color. Each isolate or type strain of mycoplasma was tested in two replicates. The MICs of tylosin, enrofloxacin, sarafloxacin, and oxytetracycline against five isolates and two reference strains of MG (approximately 10(5) colony-forming units [CFU]/ml) were 0.05, 0.14, 0.37, and 1.30 microg/ml, respectively. The MICs of the four antimicrobial agents against six isolates and one reference strain of MS (approximate 10(5) CFU/ml) were 0.13, 1.82, 1.76, and 0.91 microg/ml, respectively. There were no differences (P > 0.05) between tylosin, enrofloxacin, and sarafloxacin against MG, but these three antibiotics were different (P < 0.05) from oxytetracycline. The MIC value of tylosin against MS was different (P < 0.05) from those of sarafloxacin and enrofloxacin, but it was not different (P > 0.05) from that of oxytetracycline.

Animals↗
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A family practice model of health care for homeless people: collaboration with family nurse practitioners.

The growth of a large population of people without permanent housing in the United States has brought with it the necessity to address the unmet health needs of this group. As homelessness spreads, its demographic pattern has become more heterogeneous, with young vulnerable families now the major subgroup. This paper explores issues of homelessness in Westchester County, N.Y., which, despite being the 10th richest county in the United States, has the highest per capita homeless rate in the state. Children younger than age 18 represent the majority of this group. Barriers to the delivery of health care services are described, including fragmented life-styles, lack of insurance, insensitivity of care givers, distance from services, and inflexibility of traditional sources of health care. A model that has been developed for delivery of services is discussed. This model, the Outreach Health Care Unit, is run by nurse practitioners in collaboration with family physicians and is centered at the site of social service activities for homeless families and single men in Yonkers, N.Y. It is a collaborative endeavor of a nursing school, community hospital family practice residency program, and a network of social service agencies. The use of this model for education and research is also discussed since the goal is to provide both health services and training for health care providers.

Adolescent↗
PubMedDate not supplied

Evaluation of human sperm hyperactivated motility and its relationship with the zona-free hamster oocyte sperm penetration assay.

The authors studied hyperactivated motility of human spermatozoa as a method of evaluating capacitation by examining its relationship to results of zona-free hamster oocyte sperm penetration assays (SPA) of semen samples from 50 men attending the infertility clinic. Hyperactivated motility was assessed in the seminal plasma and after swim-up preparation of spermatozoa at 1, 3, and 24 hours of incubation in capacitation media using a computer-assisted semen analysis system equipped with a hyperactivation module. Hyperactivated motility reached a peak at 1 hour and plateaued at 3 hours. The percentage of spermatozoa in seminal plasma with star-spin hyperactivated motility was significantly lower in the group showing no penetration in the SPA. The hyperactivated motility characteristics did not differ in the groups with positive or negative penetration. Correlation analysis failed to show any significant relationship between the hyperactivated motility parameters and SPA score. When the hyperactivated motility characteristics were compared in samples with normal and abnormal semen analyses, the total percentage of spermatozoa with hyperactivated motility and the percentage with star-spin at 3 hours were significantly lower in the group with abnormal semen analysis. The data indicate that lower hyperactivated motility of spermatozoa was found in patients with a score of zero for SPA and in patients with abnormal semen analysis. It was concluded that although no direct correlations were found between the results of SPA and hyperactivated motility, evaluating hyperactivated motility may still be useful as an early indicator of capacitation abnormalities of human spermatozoa not measured by SPA.

Animals↗
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Effect of perinatal exposure to methadone on brain opioid and alpha 2-adrenergic receptors.

Prenatal exposure to psychotropic drugs has recently been shown to induce behavioral and brain neurochemical changes in the newborn. The long-term effects of pre- and postnatal exposure to methadone on the opioid (delta and mu) and adrenergic (alpha 2) receptors were investigated in two areas of the rat brain. Rat pups received prenatal treatment with methadone through a minipump implanted in the pregnant dams and were cross-fostered to methadone- or non-methadone-implanted dams until weaned. The rats were sacrificed when fully grown and brains removed. Receptor binding assays using 3H-D-ala-leu-enkephalin and 3H-naloxone for delta and mu opioid receptors respectively and 3H-rauwolscine for alpha 2-adrenergic receptors were performed in two areas of the brain. In the hypothalamus, prenatal methadone treatment induced sustained decreases in both delta and mu opioid receptors but did not cause significant changes in the alpha 2-adrenergic receptors. In the cerebral cortex, prenatal methadone treatment induced significant decreases not only in delta and mu opioid receptors but also in alpha 2-adrenergic receptors. Postnatal methadone treatment alone did not cause significant changes in opioid receptors in the two brain areas, but did induce reduction in the cerebral cortical alpha 2-adrenergic receptors. The significance of these results is discussed.

Animals↗
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Popliteal artery entrapment syndrome. A report of two cases.

Two cases of popliteal artery entrapment syndrome are added to the previously reported three cases from China. The details of the history, physical findings, and treatment of these two cases are presented, with a general discussion of the syndrome.

Adolescent↗
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Passive cross-protection provided by antisera directed against in-vivo-expressed antigens of Pasteurella multocida.

Chicken antisera produced against the detergent-insoluble fraction of in vivo-grown P-1059 (serotype 3) Pasteurella multocida passively protected against heterologous X-73 (serotype 1) challenge. Likewise, antisera from chickens that survived infection by live P-1059 provided passive heterologous protection. The two antisera, which contained cross-protection antibodies, were adsorbed with the detergent-insoluble fraction of in vitro-grown P-1059 and still passively cross-protected against heterologous serotype challenge. The proteins of in vivo-grown P-1059 that had molecular weights of 204,000, 192,000, 179,000, and 153,000, which were recognized by the adsorbed antisera on immunoblots, may be responsible for cross-protection.

Animals↗
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Identification of common antigens of serotype 1 and serotype 3 Pasteurella multocida in poultry expressed in vivo.

Eight groups of chicken immune sera and one group of turkey immune sera were used to identify unique in vivo-expressed antigens of Pasteurella multocida by Western immunoblotting. When antisera were prepared against the detergent-insoluble fraction of in vivo-grown P-1059, live X-73, live P-1059, live 86-1913, live P-1662, and live P-1702, they recognized four major antigens on immunoblots of the detergent-insoluble fraction of in vivo-grown serotype 1 and in vivo-grown serotype 3. These four antigens, which have approximate molecular weights of 204,000, 192,000, 179,000, and 153,000, were not recognized by antisera made against the detergent-soluble fraction of in vivo-grown P-1059, whole in vitro-grown inactivated X-73, or whole in vitro-grown inactivated P-1059. The results provide evidence for common antigens expressed by in vivo-grown serotype 1 and in vivo-grown serotype 3. These antigens are recognized by sera from chickens that have survived infection by various serotypes. The antigens are concentrated in the detergent-insoluble fraction of in vivo-grown bacteria and likely represent unique in vivo-expressed outer-membrane proteins.

Animals↗
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Cross-protection studies with Pasteurella multocida bacterins prepared from bacteria propagated in iron-depleted medium.

Strains X-73 (serotype 1) and P-1059 (serotype 3) of Pasteurella multocida, avian origin, expressed additional membrane proteins (MPs) when grown in brain-heart infusion (BHI) broth containing the iron chelator dipyridyl and when grown in BHI broth treated with the iron chelator Chelex 100. These additional MPs were not detected when both strains were grown in BHI broth. Chickens and turkeys were vaccinated twice with inactivated oil-emulsion vaccines containing bacterial cells expressing these MPs or with vaccines containing bacterial cells grown in BHI broth. Two weeks after the final vaccination, all birds were challenged to determine whether bacterins made from P. multocida that had been propagated in conditions of iron deprivation would induce heterologous serotype immunity. The bacterins produced in medium low in iron did not consistently induce significant protection against heterologous challenge.

Animals↗
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Methodological issues in the analysis of human sperm concentration data.

We examined two methodological issues in the analysis of sperm concentration data using a large database of sperm concentrations in healthy men that were collected at the University of Washington. We showed that the raw data were skewed and that log transformation should be used to assure that the data meet the assumptions underlying most statistical estimation and testing procedures. We also addressed the issue of the great variability in sperm concentrations within a single individual and the necessity and utility of multiple sampling to reduce variance. We conclude that log-transformed data should be used for statistical analysis of sperm concentration and recommend that such analyses be based on the geometric mean of several samples from each subject to reduce variability, increase accuracy of estimation, and improve statistical power. This is particularly important when the objective is to detect small but important differences or subtle effects.

Data Interpretation, Statistical↗
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Early effects of vasectomy on testicular structure and on germ cell and macrophage apoptosis in the hamster.

This study provides quantitative information on the early (up to 3 months) effects of vasectomy on apoptosis in the hamster testis. Groups of five adult male golden hamsters were either bilaterally vasectomized or sham-operated and sacrificed at intervals of 3, 6, and 12 weeks after surgery. In all three postvasectomy groups, testis weight and testicular and plasma testosterone (T) levels were not different from controls. Spermatogenic alterations, ranging from tubules with mild intraepithelial vacuoles to almost completely atrophied tubules, were detected in samples of 1 of 5 testes both at 3 and 12 weeks after vasectomy. Histometric analysis of testicular tissues at 3, 6, and 12 weeks in the postvasectomy groups showed no discernible effect of vasectomy on the absolute volumes of seminiferous tubules, tubular lumen, and total Leydig cells when compared to respective controls. In situ analysis of germ-cell apoptosis, characterized by 3'-end-labeling immunocytochemistry, revealed a significant increase (2.5-fold) in germ-cell apoptosis at stages XIII-I, involving primarily the dividing spermatocytes after 3 weeks of vasectomy. Apoptotic index was not changed from sham-operated animals at 6 and 12 weeks postvasectomy. Interestingly, a very high incidence of macrophage apoptosis was detected in the samples of three out of five testes in the 12 weeks postvasectomy group (39.3%) compared to that of controls (0.8%). These results demonstrate that vasectomy has little or no detrimental effect on the morphologic characteristics of the spermatogenesis or intratesticular concentrations of testosterone in the majority of the animals studied up to 12 weeks postsurgery, although vasectomy transiently (3 weeks postsurgery) activated germ-cell apoptosis, involving dividing spermatocytes at stages XIII-I.

Animals↗