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Biomedical subjects

R Wang

Publications and source records attributed to R Wang.

At least 577 records · Page 32Linked to original sources
PubMed1994

Nitric oxide mediates penile erection in cats.

The present study was undertaken to investigate the in vivo effects of nitric oxide (NO) mediating agents injected intracavernosally on penile erection in cats. All NO donors increased the cavernosal pressure and penile length in a dose-dependent manner. The maximal effects on cavernosal pressure and penile length induced by s-nitrosocysteine (NO-CYS) and s-nitroso-n-acetylpenicillamine (SNAP), respectively, were 8-fold and 5-fold increases in pressure, and 45% and 34% increases in length when compared with baseline values. These changes were comparable to that caused by the control drug combination (papaverine, phentolamine and prostaglandin E1). The effects of acetylcholine (ACh) and substance P on cavernosal pressure and penile length were less than those obtained with the control drug combination, NO-CYS (p < 0.01), or SNAP (p < 0.05). N omega-nitro-l-arginine-methyl-ester (L-NAME), a nitric oxide synthase (NOS) inhibitor, significantly decreased the effects of NO-CYS, ACh and substance P on penile erection. This in vivo study with NO donors and an NOS inhibitor suggests that NO is a mediator of penile erection in cats.

Acetylcholine↗
PubMed1994

Penile erection in the primate: induction with nitric-oxide donors.

The primate model has been used for investigations on the physiology and pharmacology of erection. Recent in vitro investigations indicate that nitric oxide acts as the mediator of penile erection, but in vivo primate studies are needed to corroborate these findings. Penile erections were induced in a primate model using intracavernosal injections of nitric oxide donors s-nitrocysteine (NO-CYS) and sodium nitroprusside (SNP), and acetylcholine (ACh) which stimulates the formation of nitric oxide. Penile length and intracavernosal pressures following agonist injection were compared with baseline (flaccid) and control erections (elicited by injection of a papaverine/phentolamine/PGE1 standard mixture). Dose-response curves for each drug were determined with respect to maximal intracavernosal pressure, duration of effect and penile length, and systemic arterial pressure was monitored. All three agents induced erections, with dose-dependent increases in cavernosal pressure and penile length. The maximal cavernosal pressure attained was similar for all three agents, but the duration of action was significantly shorter with ACh (p < .05). Injection of L-nitro-arginine-methyl-ester (L-NAME), a nitric oxide synthase inhibitor, before injection of the nitric oxide donor shortened the duration of effect but did not alter maximal cavernosal pressure or penile length attained. Although systemic hypotension was induced by each agent, digital compression at the base of the penis at the time of injection prevented such changes. These results suggest that the primate is a useful model to evaluate the action of substances that induce or inhibit penile erection. The findings provide support for the hypothesis that nitric oxide is a mediator of penile erection and that nitric oxide donors may be useful in the treatment of erectile dysfunction.

Acetylcholine↗
PubMed1994

High-accuracy mass measurement as a tool for studying proteins.

Electrospray ionization and matrix-assisted laser desorption/ionization, two new mass spectroscopy methods for the accurate measurement of molecular masses of individual peptide and protein molecules, are finding great utility for the solution of problems in biological research. Thus, mass spectrometry is being used for the rapid identification and detailed characterization of proteins, the determination of modifications in proteins, and the assessment of the integrity and purity of (native, recombinant, or synthetic) protein preparations. Recent data indicate that mass spectrometry can contribute significantly to the study of protein interactions and even to the investigation of aspects of protein folding and conformation.

Animals↗
PubMed1994

Detection of cytomegalovirus in cerebrospinal fluid autopsy specimens from AIDS patients.

Cytomegalovirus (CMV) is a common opportunistic pathogen infecting AIDS patients. Polymerase chain reaction (PCR) and antigen capture ELISA were used to detect CMV in 40 cerebrospinal fluid autopsy specimens from patients with AIDS. CMV DNA was detected by PCR in 70% of samples. Of the 21 samples from patients with systemic CMV infection, 57% had CMV encephalitis, while 81% had virus in cerebrospinal fluid detectable by PCR. Of the 24 samples from patients with no histologic evidence of CMV encephalitis, 58% had CMV DNA in cerebrospinal fluid detected by PCR. These results suggest that PCR of cerebrospinal fluid sensitively detects systemic CMV infection but is not specific for brain infection in autopsy specimens of AIDS patients.

AIDS-Related Opportunistic Infections↗
PubMed1994

Brain viral burden in HIV infection.

We quantitated the brain viral burden in autopsy material from AIDS patients with and without HIV encephalitis. Central nervous system (CNS) samples from 45 AIDS autopsies with less than 48 hours postmortem autolysis and without significant non-viral opportunistic infections were analyzed using immunocytochemistry (ICC), antigen capture assay (ACA) and polymerase chain reaction (PCR). Approximately three-quarters of the cases contained HIV DNA by PCR. The majority of these had abundant gp41 detected by ICC, but approximately one-third had no HIV p24 detected by ACA. With all assays, HIV proteins and DNA were most abundant in deep gray matter. Approximately one-quarter of the cases contained HIV p24 by ACA in both CNS tissue and cerebrospinal fluid. In more than half of the cases cytomegalovirus was detectable in the brain by PCR, however, only in the basal ganglia of one case was human herpes virus-6 detectable by PCR. In conclusion, HIV infection of the CNS was observed in the majority of AIDS autopsies, however, the quantity of virus was variable between cases and within different neuroanatomical regions. Differences between the quantitation methods could be either technical or biological, however, any of them could be used to compare assessment of HIV burden by different laboratories.

Base Sequence↗
PubMed1994

Post-thaw sperm motility, cAMP concentration and membrane lipid peroxidation after stimulation with pentoxifylline and platelet-activating factor.

Earlier studies have demonstrated that pentoxifylline (PTX) and platelet-activating factor (PAF) can significantly improve the motion parameters of post-thaw human spermatozoa. This study has investigated the effects of PAF, PTX and their combination on cyclic adenosine monophosphate (cAMP) concentrations and membrane lipid peroxidation (LPO) in post-thaw human spermatozoa. Washed spermatozoa from normal volunteers (n = 10) were cryopreserved in Test-yolk buffer using a standard protocol. After 2 weeks the sperm samples were thawed, washed and incubated with either 1 microM PAF, 3 mM PTX or 0.5 microM PAF plus 1.5 mM PTX. Video sequences were recorded at 0, 30, 60, and 120 min for analysis of sperm motion parameters using the Cell Track Sperm Analysis System. Concentrations of cAMP were assessed by radioimmunoassay, and LPO levels were measured by malondialdehyde-thiobarbituric acid reactivity. Our studies indicate a time-course stimulatory effect with overall maximal stimulation observed in samples treated with the combination of PAF and PTX. The maximal stimulation of percentage motility compared to control was observed at 60 min in samples treated with PAF, PTX, or PAF plus PTX. PAF plus PTX stimulated straight-line velocity (VSL), curvilinear velocity (VCL) and lateral head displacement (ALH) after 30 min incubation. The primary effect of PAF was observed on VSL, while the main effect of PTX was on VCL. cAMP concentrations were 3-fold higher than controls in samples treated with PTX or PAF plus PTX. cAMP concentrations in PAF-treated samples did not differ significantly from controls. No significant differences were observed between any groups for LPO.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

A convenient method for guarding against localized mucositis during radiation therapy.

Metal restorations, such as full gold crowns and dental implants, can cause forward and back scatter radiation during radiation therapy with a dose enhancement to adjacent tissues. Mucositis, one of the most common complications of the radiation treatment of oral, as well as other head and neck malignancies can result. A method for constructing a buccolingual guard in the clinical setting using hydroplastic material is described. The guard can be easily oriented and adapted to an existing radiation stent, adding positional stability and patient comfort. When adequate thickness of material is used, the guard can attenuate forward and back scatter radiation, separate the adjacent tissues from metal restorations, and protect the oral mucosa from localized incidents of mucositis.

Carcinoma, Squamous Cell↗
PubMed1994

Effects of Buthus martensii Karsch scorpion venom on the release of noradrenaline from in vitro and in vivo rat preparations.

The aim of this study was to test the neuronal effects of the Chinese Buthus martensii Karsch (BMK) scorpion venom in vivo and in vitro in order to understand the mechanism involved in the cardiovascular pressor effect of this venom. In conscious unrestrained rats, administration of 100 micrograms/kg i.v. BMK venom induced an increase in blood pressure, which was associated with a significant increase in plasma noradrenaline. In isolated atria, BMK also induced an increase in the stimulation-induced release of [3H]noradrenaline in a dose-dependent manner. The modulatory effect of agents acting at sympathetic prejunctional adrenoceptors on [3H]noradrenaline release was not altered by BMK venom administration. Finally, it was observed that 100 micrograms/mL BMK venom increased the intracellular calcium concentration in acutely dissociated sympathetic neurons from adult rat superior cervical ganglion. This action appeared to be mainly due to an influx of extracellular calcium. BMK venom induced a small rise in intracellular calcium in the absence of external calcium, indicating that it may also mobilize calcium from intracellular stores. The results observed in this study suggest that BMK venom may induce pressor responses by releasing noradrenaline from the sympathetic nerve terminals and that activation of neuronal calcium channels may be involved in that process.

Animals↗
PubMed1994

Family-based intervention for schizophrenic patients in China. A randomised controlled trial.

BACKGROUND: We developed and evaluated a comprehensive, ongoing intervention for families of schizophrenic patients appropriate for China's complex family relationships and unique social environment. METHOD: Sixty-three DSM-III-R schizophrenic patients living with family members were enrolled when admitted to hospital and randomly assigned to receive standard care or a family-based intervention that included monthly 45-minute counselling sessions focused on the management of social and occupational problems, medication management, family education, family group meetings, and crisis intervention. RESULTS: At 6, 12, and 18-month follow-ups by blind evaluators, the proportion of subjects rehospitalised was lower, the duration of rehospitalisation was shorter, and the duration of employment was longer in the experimental group than in the control group; these differences were statistically significant at the 12 and 18-month follow-ups and were not explained by differences in drug compliance. Family intervention was associated with significantly lower levels of family burden. CONCLUSIONS: This intervention is less costly than standard treatment, is suitable for urban families of schizophrenic patients in China and feasible given the constraints of the Chinese mental health system.

Adolescent↗
PubMed1994

[Immunohistochemical study of the olfactory mucosa and vomeronasal organ in rat, guinea pig and human fetus].

Immunohistochemical examination for neuron-specific enolase (NSE), S-100 protein and cytokeratin (CK) was performed in the olfactory mucosa and Jacobson's vomeronasal organ of rat, guinea pig and human fetus. The results indicated that: 1) The combined immunohistostaining used in this study made it possible to examine the normal morphology and pathology of the olfactory mucosa; 2) The NSE immunoreactivity was recognized in the Jacobson's vomeronasal organ of the adult rats and guinea pigs. The vomeronasal organ of human fetuses below 5 months showed positive immunoreactivity for NSE, but the NSE immunoreactivity of the vomeronasal organ in fetuses above 7 months was not confirmed. So we conclude that human vomeronasal organ is possibly a regressive organ. It is unlikely to have any olfactory function as it does in rodent animals.

Animals↗
PubMed1994

[Clinical observation on 172 cases of N.S. diseases treated by PCE-88A type of the programmed electroacupuncture apparatus].

We have treated 172 cases of N.S. diseases with PEC-88A Type of the Programmed Electroacupuncture Apparatus with shows of frequency and voltage of electro-pulse. Of 172 cases, 47 cases were cured (27.3%), 77 markedly effective (44.8%), 44 improved (25.6%), 4 failed (2.3%). The total effective rate was 97.7%. The observation showed that different stimulating strength was needed to different disease through observation of the stimulating strength of electroacupuncture. The strongest was for the sequela of poliomyelitis. The next was for the sequela of apoplexy. The lightest was for sciatica, and during treatment the stimulating strength to disorder side is larger than one of normal side. By the way, the stimulating strength of electroacupuncture was reduced step by step while the disease become better little by little.) The result of clinical observation displaced that the stimulating strength was determined according to the part of injured N.S and patient's sensitivity to the stimulating strength of electroacupuncture when using electroacupuncture.

Adolescent↗
PubMed1994

[The embryonic development of the ostiomeatal complex from 8 to 40 weeks].

The embryonic development of the ostiomeatal complex from 8-40 weeks was studied under the light microscope. From our observation, the uncinate process was visible on the laterosuperior portion of the inferior turbinate at 8 week's gestation. By 12 weeks, the ethmoid bulla was first identifiable on the lateral wall of the middle meatus. The primordial ethmoidal infundibulum and primordial maxillary sinus were seen developing lateral to the uncinate process in the middle meatus. The air cells of the middle turbinate may be normal development of the ethmoidal labyrinth. Congenital nasal septum deviation may cause malformation of the ostiomeatal complex.

Embryonic and Fetal Development↗
PubMed1994

[Regulation on beta-END in tumor-bearing mice by moxibustion on Guanyuan point].

The experimental results demonstrated that moxibustion on Guanyuan point could promote the hyperplasia of the pituitary and the adrenal gland which showed atrophy in control group. Also, the moxibustion treatment stimulated the secretion of beta-END from the pituitary and the adrenal gland, increased the level of serum beta-END significantly and kept the high level for quite a long time, that was advantageous for beta-END to carry out the immunomodulation. The data further suggested that moxibustion treatment do not cause the instant release but probably constant release of the beta-END.

Acupuncture Points↗
PubMed1994

[A study on the resistance of methicillin resistant Staphylococcus aureus to antimicrobial agents].

The morbidity of the infections caused by methicillin resistant staphylococcus aureus increased in recent years. In order to know the resistance of MRSA to antimicrobial agents, the minimal inhibitory concentrations (MICs) of antimicrobial agents against S. Aureus isolated from inpatients were measured. The presence of beta-lactamase in and the types of coagulase of the strains tested were determined as well. The results showed that MRSA accounted for 50.7% of the strains tested, the incidence of MRSA producing beta-lactamase was 85.1% and the coagulase of MRSA was all of type II. MRSA showed resistance to most of the lactam antibiotics and some of the aminoglycosides. Vancomycin and arbikacin had the highest activity against MRSA; other effective antibiotics were in the following order: amikacin, minocycline, tosulfloxacin and imipenem. It is suggested that serious infections caused by MRSA may be cured by using vancomycin, arbikacin or other antibiotics mentioned above.

Aminoglycosides↗
PubMed1994

Developmental analysis of bone tumors in polyomavirus transgenic mice.

BACKGROUND: Transgenic mice carrying the polyoma (Py) early region gene develop both vascular and bone tumors that express the transgene (R. Wang and V. L. Bautch, J. Virol. 65:5174-5183, 1991). To determine the correlation between bone tumor formation and transgene expression, mice of two lines that showed differences in tumor pattern were analyzed. EXPERIMENTAL DESIGN: Py DNA encoding the early region gene was inserted into B6D2F1 mouse embryos. Transgenic mice were sacrificed at appropriate times in development, and the histopathology of the skulls and genotype analyses were performed independently. Py transgene expression was assayed in individual skulls or small groups of skulls. RESULTS: In mice of the Py-4 line, Py oncogene expression was detectable in skulls from 14.5 days of development. These mice had normal skulls at birth, and they developed lesions histologically resembling osteosarcoma synchronously 1 to 2 weeks after birth. Mice of the Py-3 line did not express detectable levels of transgene at 3 weeks of age, and they did not develop detectable skull pathology at this age. Less than 20% of adult Py-3 mice developed calvarial osteosarcoma-like lesions, and a similar number of these mice expressed the transgene in the skull. CONCLUSIONS: These data show that Py transgene expression in bone of the skull is differentially regulated in mice of the two lines, and they indicate that epigenetic changes may be sufficient to complement expression of the Py oncogene in neoplastic bone formation during development.

Animals↗