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Biomedical subjects

M Wang

Publications and source records attributed to M Wang.

At least 883 records · Page 49Linked to original sources
PubMed1993

Type IV collagenase (M(r) 72,000) expression in human prostate: benign and malignant tissue.

The expression of type IV collagenase (M(r) 72,000) has been examined in tissues from patients with benign prostatic hyperplasia (6 patients) and varying Gleason grades of malignant prostate cancer (18 patients). Immunoperoxidase labeling indicated that expression of the type IV collagenase was weak or nonexistent in benign tissue but consistently strong in the glandular and ductal epithelial cells of prostate tumors diagnosed at Gleason grades 1-8. In moderate to advanced cancer (i.e., Gleason grades 2 to 8), invasive tumor foci in the stromal tissue produced relatively modest amounts of type IV collagenase. The normal stromal tissue (i.e., fibroblasts) uniformly failed to produce detectable levels of type IV collagenase in the 24 patients examined. Northern and quantitative slot blot hybridization assays demonstrated that collagenase type IV mRNA levels were low in benign tissue and high in malignant tumors. In contrast, the stromal cells did not express significant amounts of type IV collagenase mRNA. Enzyme-linked immunosorbent assays demonstrated that the amounts of type IV collagenase protein correlated directly with the mRNA levels in the tumor tissue. The studies suggest that type IV collagenase may be selectively overexpressed by malignant, preinvasive prostatic epithelial cells.

Blotting, Southern↗
PubMed1993

Sequence and genomic organization of Norwalk virus.

A library of overlapping cDNAs obtained from Norwalk virus purified from stools of human volunteers (Jiang et al., 1990, Science 250, 1580-1583) was used to obtain the nucleotide sequence of the viral genome. The sequence has a total of 7642 nucleotides, excluding the 3' poly(A) tail, and has a base composition of 48% G + C. Three open reading frames (ORF) are predicted in the sequence. The longest ORF (ORF1, nucleotides (nt) 146 to 5359) is predicted to encode a polyprotein precursor to nonstructural proteins based on identification of sequences similar to the picornavirus 2C protein, 3C protease, and 3D RNA-dependent RNA polymerase. ORF2 (nt 5346 to 6935) is predicted to encode a polypeptide with a predicted molecular weight of 56,571 (56.6K, close to the expected size of the viral capsid protein), and it contains a short region of sequence similarity to the picornavirus structural protein VP3. A third potential ORF (nt 6938 to 7573) could encode a small polypeptide of 22.5K. The genomic organization found in Norwalk virus shares striking similarities with the genome of two caliciviruses, the feline calicivirus and the rabbit hemorrhagic disease virus. The morphology, size, polarity, and genomic organization of the Norwalk virus indicate it is a member of the Caliciviridae family.

Base Sequence↗
PubMed1993

Epitope mapping studies with neutralizing and non-neutralizing monoclonal antibodies to the G1 and G2 envelope glycoproteins of Hantaan virus.

Epitopes recognized by three G1-specific and two G2-specific neutralizing monoclonal antibodies to Hantaan virus were mapped by sequence analyses of the complete M genome segments of neutralization escape variant viruses. For each variant, we detected nucleotide sequence substitutions which resulted in a single amino acid change in either the G1 or G2 protein. Serological properties of the variant viruses correlated with changes identified by nucleotide sequence analyses. To map epitopes recognized by three G1-specific and six G2-specific, non-neutralizing monoclonal antibodies, we prepared genes, truncated at the carboxy terminal coding regions of G1 or G2, and expressed them with baculovirus recombinants or transiently in a vaccinia/T7 RNA polymerase system. Reactivities of the monoclonal antibodies with the truncated proteins were monitored by immune precipitation of the radiolabeled, truncated glycoproteins. We determined that all three of the G1-specific antibodies reacted with truncated proteins, which retained the amino terminal one-third of G1, but lost reactivity with shorter G1 proteins. The G2-specific antibodies only recognized G2 proteins, which retained approximately 80% of the G2 gene.

Amino Acid Sequence↗
PubMed1993

Risk factors on the occurrence of response fluctuations and dyskinesias in Parkinson's disease.

We studied the risk factors that influence the occurrence of response fluctuations and dyskinesias in 194 patients with Parkinson's disease (PD). These factors included age at onset, disease severity at levodopa initiation, duration of illness prior to levodopa therapy and the daily dose of levodopa at the end of study. The first three were fixed covariates and the last one was time-dependent. Patients with age onset before 50 years showed a higher risk of developing response fluctuations (RF) and dyskinesias in univariate analysis. We estimated the combined effects of these covariates through multivariate analysis and found that the age at onset was the sole factor related to the incidence of both complications. Additionally, it was the only variable that could enter the predictive model of stepwise regression. Our observation suggested that age at onset determined the occurrence of RF and dyskinesias. Patients with younger age at onset had higher risk of developing these adverse effects.

Adult↗
PubMed1993

Sterilization of dogs with intra-epididymal injection of zinc arginine.

Condoms and vasectomy are the only fertility control methods available to males. Fifty million surgical vasectomies have been performed worldwide. In spite of improvements in the surgical techniques, the widespread use of vasectomy is limited due mainly to fear of genital operation. Chemical sterilization offers a promising new approach as an alternative to surgery. Fifteen sexually mature, mixed breed, male dogs, 2-3 1/2 years of age and weighing 22 +/- 1.8 kg, were divided into two groups. Five control placebo animals were injected with 0.5 ml of saline into the cauda epididymis, and ten treated animals were injected with 0.5 ml of 50 mg of zinc arginine into the cauda epididymis. Semen analysis performed before injection showed no significant difference between control placebo and treated groups. The control placebo animals exhibited a significant reduction in sperm motility one month after injection, which returned to normal within two months, and no change in semen volume, sperm abnormalities, or sperm concentration analyzed monthly for twelve months. The zinc arginine-treated animals achieved azoospermia ninety days after injection. The dogs were sacrificed one year after injection. There was no significant reduction of reproductive organ weights of the treated group as compared to the control placebo group. Although histological examination of the testes revealed normal seminiferous tubules, there was atrophy of the rete testes of the zinc arginine-treated group and, thus, increase in connective tissue. Histological examination of epididymides of the zinc arginine-treated group indicated that none of the cells in the head, body, and tail of the epididymis and ductus deferens contained sperm; 90% of the coils were empty and 10% contained amorphous pink cell debris; the coils decreased in diameter and were lined by cuboidal to columnar epithelium; no granuloma was observed. There was no significant change in serum testosterone level of control placebo and treated groups. These results offer the possibility of a new method of permanent sterilization instead of surgery. Zinc is considered to be nonmutagenic, noncarcinogenic, and nonteratogenic.

Analysis of Variance↗
PubMed1993

Competitor mRNA fragments for quantitation of cytokine specific transcripts in cell lysates.

Synthetic RNAs (sRNAs) specific for four human cytokines were constructed and used as an exogenous internal standard in a quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The sequences of the sRNA and the target mRNA were identical except for a duplication or deletion of approximately 100 nucleotides. The size difference between these two templates permitted easy electrophoretic separation of their PCR products. The sRNA has polyadenylated sequences at the 3' end and can be added directly either to a cell lysate before RNA purification or to a reverse transcription reaction. One pair of primers is used to amplify the internal standard and the target simultaneously, and the ratio of the two PCR products remains constant throughout the amplification. This technique can be applied to quantitate specific mRNA in as few as 10 cells when the exogenous control is added directly to cell lysates. This method is sensitive, accurate and adaptable for quantitation of other transcripts.

Blotting, Northern↗
PubMed1993

Expression of 5 alpha-reductase in bacteria as a trp E fusion protein and its use in the production of antibodies for immunocytochemical localization of 5 alpha-reductase.

A cDNA encoding a full-length rat 5 alpha-reductase was isolated using female rat liver mRNA and the polymerase chain reaction, and fused to the Escherichia coli trp E gene in a pATH expression vector. The trp E-5 alpha-reductase fusion protein expressed in bacteria and a synthetic oligopeptide corresponding to the C-terminus of rat 5 alpha-reductase were used as antigens to produce rabbit polyclonal antibodies to 5 alpha-reductase. Antibodies to the 5 alpha-reductase portion of the fusion protein and to the peptide were purified by affinity chromatography. Antibodies against the 5 alpha-reductase fusion protein reacted with a single component of rat liver microsomes with M(r) 26,000 on Western blots, consistent with the size of 5 alpha-reductase predicted from its cDNA, and with a M(r) 23,000 component on Western blots of detergent extracts of rat ventral prostate nuclei; other rat ventral prostate cellular fractions (mitochondrial, microsomal, cytosol) bound little or no antibody. Antibody against the synthetic peptide reacted with a M(r) 26,000 component of rat liver microsomes as well as with several components in various cellular fractions of rat ventral prostate. With anti-5 alpha-reductase fusion protein antibodies, specific immunocytochemical staining was observed in the epithelial cell nuclei of the rat ventral prostate, seminal vesicle, epididymis and other accessory sex glands. This nuclear staining was specific, since antibodies from non-immunized rabbits did not give nuclear staining and preincubation of the anti-5 alpha-reductase fusion protein antibodies with the trp E-5 alpha-reductase fusion protein eliminated nuclear staining. Incubation of antibodies with trp E (without the 5 alpha-reductase fusion) had no effect on nuclear staining. Specific staining was not detected in the cytoplasm of these epithelial cells. Little or no specific staining was observed in stromal cells in these rat tissues. Human prostate was also immunocytochemically stained with this antibody. Specific staining was found in both epithelial and stromal cell nuclei.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1993

Modified longitudinal preputial island flap urethroplasty for repair of hypospadias: results in 60 patients.

We report the results of hypospadias repair in 60 children requiring urethral reconstruction using a longitudinal or oblique preputial island flap technique that includes the inner and outer surfaces of the prepuce to construct the neourethra. Mean patient age was 3.2 years and mean length of the repair was 3.1 cm. The cosmetic and functional results were satisfactory. The incidence of urethrocutaneous fistula was 8.3% and that of meatal stenosis was 5%. Thus, this modification offers good results with a low complication rate. The range of applications can be extended by combining the technique with a tube of midline scrotal skin in cases of scrotal or perineal hypospadias. The surgical technique is described in detail.

Child, Preschool↗
PubMed1993

Effects of ultraviolet radiation on contact lens parameters.

Ultraviolet (UV) radiation has been proposed as an alternative method for contact lens disinfection. In order for UV radiation to be considered a viable contact lens disinfection method, its effects on lens polymers and parameters must be minimal. To evaluate this, soft contact lenses from each of the four FDA categories, soft lenses with handling tints, and rigid gas permeable (RGP) lenses were exposed to UV radiation in a controlled laboratory setting and their parameters measured. After 20 h of UV exposure, we found statistically significant changes in at least one parameter for each lens type evaluated. Most of these changes were small and within the error of measurement and, therefore, were not considered clinically significant. However, the group 2 soft lenses showed an increase in all four measured parameters--power, center thickness, diameter, and water content. These changes may have an impact on lens fitting characteristics and performance. Other than these changes for group 2 soft lenses, 20 h of UV exposure appeared to have little clinical effect on the contact lenses evaluated. This suggests that UV radiation may prove to be a feasible alternative method of disinfection for most types of contact lenses.

Contact Lenses, Hydrophilic↗
PubMed1993

The synergistic interactions in vitro and in vivo of brequinar sodium with cyclosporine or rapamycin alone and in triple combination.

The rigorous median-effect analysis was used to assess the interactions between cyclosporine and drugs that inhibit nucleotide synthesis pathways. Using in vitro proliferation assays wherein human lymphocytes were triggered by phytohemagglutin, anti-CD3 monoclonal antibody, or mixed lymphocyte reactions, CsA was shown to display additive interactions with 6-mercaptopurine (6-MP), mizorbine (MZB), and mycophenolic acid (MPA), and a synergistic interaction with brequinar (BQR). In the in vitro assays, BQR contributed a further synergistic effect to the double-drug combination CsA/rapamycin (RAPA). Of the four inhibitors of nucleotide synthesis pathways, only BQR noncompetitively inhibited IL-2-stimulated proliferation of the CTLL-2 cell line. Using the in vivo assay of heterotopic Buffalo (BUF, RT-1b) cardiac allografts in Wistar-Furth (WFu, RT-1u) hosts, oral administration of BQR displayed about 100% bioavailability--which, like the bolus intravenous (i.v.) mode, was eight-fold more effective than continuous i.v. infusions. Furthermore median-effect analysis of serial amounts of orally administered BQR demonstrated that it contributes synergistically to the immunosuppressive effects of intravenously delivered CsA/RAPA (0.5/0.01 mg/kg/day). The degree of synergism was proportionate to the extent of the immunosuppression. These findings document the potency of the CsA/RAPA/BQR triple-drug combination and suggest that the synergistic effects may permit dose reductions of each component, thereby mitigating toxicities resulting from the large amounts of individual agents necessary to achieve allo-unresponsiveness.

Antibodies↗
PubMed1993

Expression of non-conserved regions of the S genome segments of three hantaviruses: evaluation of the expressed polypeptides for diagnosis of haemorrhagic fever with renal syndrome.

Haemorrhagic fever with renal syndrome (HFRS) is a serious and often fatal disease caused by viruses in the Hantavirus genus of the family Bunyaviridae. We expressed the entire coding region of the small (S) genome segments of three serologically distinct hantaviruses as soluble proteins in Escherichia coli and evaluated the expressed nucleocapsid proteins (NPs) as antigens for diagnosis of HFRS. We also prepared novel diagnostic antigens by expressing truncated genes from which we deleted amino acid coding regions that were highly conserved among the three viruses. These antigens were analysed for their potential to detect and differentiate between antisera to various hantaviruses by ELISA. ELISA results obtained with HFRS patient sera or with sera from naturally or experimentally infected animals indicate that homologous antigens and antisera reacted to high titre. The truncated NPs were more specific than the complete NPs in distinguishing between possible aetiological agents of HFRS. Our findings demonstrate that prokaryotic expression of portions of the NPs of specific hantaviruses can be used to generate, readily and efficiently, large quantities of antigen that is both sensitive and specific in diagnostic assays for HFRS.

Animals↗
PubMed1993

Human trichohyalin gene is clustered with the genes for other epidermal structural proteins and calcium-binding proteins at chromosomal locus 1q21.

Trichohyalin is a major differentiation product of hard keratinizing tissues such as the inner root sheath and medullary cells of the hair follicle and the filiform papillae of the tongue, as well as terminally differentiating epidermal cells. It consists largely of quasi-repeating peptide repeats and functions primarily as an intermediate filament-associated protein in these tissues. By mapping with human-rodent somatic cell hybrids and fluorescent in situ hybridization, we demonstrate that its gene maps to chromosomal region 1q21. Interestingly, genes encoding several other structural proteins expressed during terminal differentiation in the epidermis map to this region, as do also several members of the S-100 class of small calcium-binding proteins.

Blotting, Southern↗
PubMed1993

Inherited congenital adrenal hyperplasia in the rabbit is caused by a deletion in the gene encoding cytochrome P450 cholesterol side-chain cleavage enzyme.

Congenital adrenal hyperplasia (CAH) comprises a family of inherited human disorders caused by a defect in cortisol biosynthesis. We previously reported absent cholesterol side-chain cleavage enzyme cytochrome P450 (P450scc) expression in rabbits affected with CAH. Further molecular studies via Southern blotting analyses, using a full-length human P450scc cDNA probe and a cloned rabbit P450scc cDNA probe, demonstrated the absence of P450scc DNA fragments in CAH animals. Reverse transcriptase-based polymerase chain reactions revealed that P450scc mRNA was not detectable in the adrenals of CAH rabbits, confirming the previous findings of absent P450scc gene expression by Northern and Western blotting. Cloning and sequencing of a 1336-basepair fragment of rabbit P450scc cDNA (85% of the coding sequence) revealed an approximately 80% identical nucleotide sequence and a 76% identical amino acid sequence compared to the human P450scc cDNA. We conclude that a large deletion mutation in the P450scc gene is most likely responsible for the absent P450scc gene expression resulting in the lethal and feminizing form of CAH in the rabbit. Further investigation of adrenal and gonadal steroidogenic enzyme gene expression in this CAH animal model will provide a greater understanding of the molecular genetics of CAH, while wild-type P450scc gene transfer experiments using CAH adrenals in vitro or in vivo will ultimately characterize the molecular basis of CAH and provide a foundation for CAH gene therapy modality.

Adrenal Hyperplasia, Congenital↗
PubMed1993

Angiogenic oligosaccharides of hyaluronan enhance the production of collagens by endothelial cells.

The present study demonstrates a relationship between angiogenic oligosaccharides of hyaluronan (HA) and the production of collagens during the process of angiogenesis in vivo and in vitro. The addition of angiogenic oligosaccharides of HA to the chorioallantoic membrane of the chick embryo induced a deposition of collagen fibrils. The treatment of sub-confluent cultures of bovine aortic endothelial cells with the same oligosaccharides (1 microgram/ml) increased the uptake of [3H]proline by approximately 60%. SDS-polyacrylamide gel electrophoresis of treated cultures demonstrated the enhanced synthesis of type I and type VIII collagens. The production of type VIII collagen was confirmed by western blotting and immunocytochemistry using antibodies to sheep and bovine type VIII collagen. Type VIII collagen is a short chain collagen that has a high degree of homology to cartilage-specific type X collagen. The biological functions of type VIII and type X collagens are unknown. We have suggested that the two collagens play a role in the process of angiogenesis.

Animals↗