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Biomedical subjects

S Zhou

Publications and source records attributed to S Zhou.

At least 433 records · Page 24Linked to original sources
PubMed1994

Expression of the beta-adrenergic receptor-adenylylcyclase system in basal and columnar airway epithelial cells.

Catecholamines acting through the beta-adrenergic receptor (beta AR) coupled-adenylylcyclase system stimulate a variety of responses by airway epithelial cells which affect airway caliber and the response to inflammatory stimuli. Although the tracheobronchial epithelium (TBE) is composed of several phenotypically differentiated cell types, surprisingly little is known about the expression of the beta AR system by the major subpopulations of TBE cells (i.e., basal and columnar). We, therefore, examined the function of the beta AR system in columnar and basal cell-enriched populations of rabbit tracheocytes. Cells were collected from 35 rabbits in 17 separate experiments and separated into basal and columnar cell-enriched fractions by centrifugal elutriation. The columnar fraction demonstrated a significantly greater (P < 0.005) adenosine 3',5'-cyclic monophosphate (cAMP) response to isoproterenol (10(-9)-10(-5) M) than the basal cell-enriched fraction (i.e., 74.7 +/- 5.1 and 49.4 +/- 2.8 pmol/10(6) cells, in columnar and basal cell-enriched fractions, respectively, P < 0.0001) as well as a higher beta AR density (i.e., 8,678 +/- 840 and 4,754 +/- 406 beta AR sites/cell, respectively, P < 0.0001). However, when corrected for differences in cell size assessed from measurements of total cell protein, cAMP production per milligram protein and beta AR density per milligram protein were similar in the two cell fractions (P > 0.50 for both comparisons). beta AR subtype assessed by beta 1AR and beta 2AR subtype selective antagonists demonstrated that the beta 2AR subtype predominated (i.e., > 90%) in both cell populations (P > 0.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1994

Functional behavior of the beta-adrenergic receptor-adenylyl cyclase system in rabbit airway epithelium.

Stimulation of adenylyl cyclase mediates the effects of beta-adrenergic agonists and prostaglandin E2 (PGE2) on tracheobronchial epithelial cell function by increasing intracellular cyclic adenosine monophosphate (cAMP). In turn, increases in cAMP affect airway function by modulating ciliary beating, chloride and water transport, mucus secretion, and release of bronchoactive substances. This study examined the function and regulation of the beta-adrenergic receptor-adenylyl cyclase system (beta AR-AC) in tracheal epithelial cells isolated from the rabbit, a frequently used animal model of airway reactivity, inflammation, and electrolyte transport. beta AR number, assessed by ligand binding using the non-subtype-specific beta-antagonist [125I]iodopindolol, averaged approximately 10,700 beta AR/cell (400 fmol/mg membrane protein). Greater than 85% of the receptors were of the beta 2 subtype as determined by competitive antagonist displacement of iodopindolol by selective beta 1- (betaxolol) and beta 2- (ICI 118,551) antagonists. cAMP synthesis was stimulated with isoproterenol, PGE2, and forskolin in a time- and concentration-dependent fashion. Preincubation of epithelial cells for 30 min with either isoproterenol (10 microM) or the peptide inflammatory mediator, bradykinin (100 microM), markedly depressed subsequent isoproterenol-stimulated cAMP synthesis. Isoproterenol-induced beta AR-AC desensitization appeared to be homologous since cAMP responses to PGE2 and forskolin, a direct activator of adenylyl cyclase, were not reduced. The effect of bradykinin on isoproterenol-stimulated cAMP response was mimicked by preincubation with either dioctanoyl glyceride or phorbol myristate acetate, activators of protein kinase C.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1994

Histocytochemistry of glycoconjugates in nasal inverted papilloma.

In order to investigate the changes in cellular distribution of the glycocalyces in nasal inverted papilloma, formalin-fixed, paraffin-embedded biopsy specimens of inverted papilloma were analyzed by the avidin-biotin-peroxidase complex technique for the demonstration of peanut agglutinin (PNA) receptors, concanavalin A (Canavalia ensiformis agglutinin; ConA) receptors, carcinoembryonic antigen (CEA), and keratin, and compared with normal nasal mucosa, nasal polyps, and papillary adenocarcinoma. The inverted papillomas were positive for PNA and CEA, to the same degree as papillary adenocarcinoma. Their PNA binding was related to the degree of dysplasia. The ConA reaction was intermediate between that of normal mucosa and adenocarcinoma. The results suggest that the alteration of cellular glycoprotein structure in inverted papilloma is associated with its biologic characterization.

Adult↗
PubMed1994

[Experimental study on the reinnervation of the vocal cord adductor by implantation of ansa cervicalis].

The sub-branches of main branch of ansa cervicalis were cut and implanted into the thyroarytenoid and lateral cricoarytenoid muscles on the left side in 7 dogs after the recurrent and superior laryngeal nerves were sectioned on the same side. After six months, laryngoscopy showed that adduction of the vocal cord recovered in five post-operative cases. Adduction was caused by the reinnervated adductor muscles, as demonstrated by laryngeal electromyography, histologic studies, tension of contraction and electron microscopy for the neuro-muscular junctions. The present results demonstrated that the procedure seemed to produce satisfactory reinnervation of the adductor musculature.

Animals↗
PubMed1994

[Experimental study on delayed reinnervation of vocal cord adductors].

The adductor branch was anastomosed with the main branch of ansa cervicalis to reinnervate the vocal cord adductors in six dogs at the time of denervation and after varying intervals of chronic denervation. Some recovery of adduction was noted within ten-month interval. Laryngeal electromyography, tension tests and histologic studies of the adductor muscles were correlated with the recovery of adduction. Although adduction didn't recover after twelve-month interval, striations of the adductor muscles were normal, only slight fibrosis was observed.

Anastomosis, Surgical↗
PubMed1994

[Effects of phenytoin and cabamazepine on sex hormones in male patients with epilepsy: a controlled study].

We measured the levels of estradiol (E2), total testosterone (TT) and free testosterone (FT) in 24 male patients with epilepsy receiving phenytoin (DPH), 21 male patients with epilepsy receiving cabamazepine (CBZ), 23 male epileptics receiving no treatment, and in 10 healthy age-matched male controls. The FT and TT levels of the DPH group were significantly lower and higher than those of the normal control group, respectively. The E2, FT and TT of the CBZ group were all lower than those of the normal controls. The results showed the difference between DPH and CBZ in the mechanism of affecting the levels of sex hormones; therefore, the treatments should not be the same.

Adolescent↗
PubMed1994

[Study of effects of Chinese herbal prescription combined with copper, iron on malignancy of cancer cells].

BALB/c mice bearing ascitic liver cancer were used, and Chinese herbal prescriptions combined with Cu and Fe (CHCF) was given by gavage continuously for 10 days, and some cell biological parameters were measured; furthermore, the ascitic cancer cells (control and treated group) were removed, and retransplanted to another mice and observed. The results showed that in CHCF treated group, DNA content of the cancer cells was decreased, and the proliferation index (PI) was reduced (control: 83.4 +/- 2.6, CHCF group: 78.8 +/- 1.5; or control: 67.2 +/- 1.3, CHCF group: 64.2 +/- 1.6, P < 0.05). The number of the cancer cells in G1 phase increased obviously, but, those of S+G2M phases decreased considerably (P < 0.05-0.01); on the DNA histogram, the diploid peak became higher and bigger, but multiploid peaks became smaller. Furthermore, retransplanted experiments showed that in 2/10 animals, the tumor did not grow, the growth inhibition rate was 71.7%-88.3%; and the survival period of retransplanted animals was prolonged significantly (from 26.1 +/- 11.8 days to 38.1 +/- 9.6 days, or to 39.6 +/- 7.2 days, P < 0.01); the increase in life span was 46%-52% respectively. These results suggested that CHCF could decrease the malignancy of liver cancer cells in mice.

Acetates↗
PubMed1994

[Inotropic effect of novel domestic cardiotonic agent, vesnarinone--test in vitro].

This paper reports the studies on the positive inotropic effect of the novel domestic cardiotonic agent, vesnarinone on isolated papillary muscle and atrium of guinea pigs and rabbits, and on the comparison of the positive inotropic effect and toxicity of vesnarinone with amrinone, milrinone and strophanthin. The result suggests that vesnarinone has an apparent dose-effect relationship on a positive inotropic effect, the strength of which is between amrinone and milrinone. The positive inotropic effect of vesnarinone is higher and the toxicity is lower than that of strophanthin.

Amrinone↗
PubMed1994

[Experimental studies on the selective reinnervation of the abductor and adductor muscles of the larynx].

Fifteen adult dogs were divided into three groups randomly in the experiment. Function rehabilitation of the adduction and abduction after vocal cords paralysis was attempted by selective reinnervation of the laryngeal muscles. Observation showed: onset of recovery of spontaneous adduction was 3 months following surgery, whereas onset of spontaneous abduction was 4 months postoperatively, all experimental animals except control group successfully regained synchronous adduction and abduction in 6 months after operation. Electromyography, tension of contraction of laryngeal muscles and histology studies were performed at 6 months postoperatively. The results demonstrated that it was possible and successful to reinnervate the adductor and abductor muscles of the larynx. Moreover, the delay of reinnervation of laryngeal muscles is discussed in the article.

Animals↗
PubMed1994

The neural retina maintains integrins in the apical membrane of the RPE early in development.

PURPOSE: The retinal pigment epithelium (RPE) lines the interface between the neural retina and the choroid. Early in chicken development, the beta 1 family of integrins resides in the apical (facing the neural retina) and basolateral (facing the choroid) membranes of RPE. Later in development, integrins reside only in the basolateral membranes, which is more typical of simple transporting epithelia. The authors examined whether the distribution of integrins is regulated by the neural retina. METHODS: Individual integrins were examined by studying the individual alpha-subunits that form heterodimers with the beta 1 subunit. The expression and distribution of these subunits were determined by immunoblotting and immunocytochemistry. RESULTS: Subunits alpha 3 and alpha 6 exemplified contrasting behaviors. Early and late in development, alpha 3 was found only in the basal membranes. As was beta 1, the distribution of alpha 6 was nonpolarized early in development but was basal later in development. The effect of the immature neural retina was determined by reconstituting the RPE:neural retinal interface in explant culture. Absent the neural retina, alpha 6 and beta 1 were removed from the apical membrane. When present, the immature neural retina maintained both subunits in the apical membrane. The neural retina was effective only if the outer (primordial photoreceptor) surface of the retina apposed the RPE. CONCLUSIONS: These data suggest that matrix or intercellular interactions determine the distribution of individual integrins. Further, the changes in integrin distribution during development reflect the maturation of the primordial interphotoreceptor matrix or photoreceptor cell layer.

Animals↗
PubMed1993

The synapse-specific phosphoprotein F1-20 is identical to the clathrin assembly protein AP-3.

F1-20 and AP-3 are independently described, synapse-associated, developmentally regulated phosphoproteins with similar apparent molecular masses on SDS-polyacrylamide gel electrophoresis (PAGE). F1-20 was cloned and characterized because of its synapse specificity. AP-3 was purified and studied biochemically because of its function as a clathrin assembly protein. Here we present evidence that establishes the identity of F1-20 and AP-3. Monoclonal antibodies against F1-20 and AP-3 both specifically recognize a single protein from mouse brain with an apparent molecular mass of 190 kDa on SDS-PAGE. These monoclonal antibodies also specifically recognize the cloned F1-20 protein expressed in Escherichia coli. The anti-F1-20 monoclonal antibody (mAb) stains a bovine protein with an apparent molecular mass on SDS-PAGE of 190 kDa that copurifies with brain clathrin-coated vesicles (CCVs) and that can be extracted from the brain CCVs under conditions that extract AP-3. The anti-F1-20 and anti-AP-3 mAbs specifically recognize the same spot on a two-dimensional gel run on a bovine brain clathrin-coated vesicle extract. AP-3 purified from bovine brain CCVs is recognized by both the anti-F1-20 and anti-AP-3 mAbs. Purified preparations of bovine AP-3 and bacterially expressed mouse F1-20 give identical patterns of protease digestion with bromelain and subtilisin. Sequence analyses reveal that F1-20 has an essentially neutral 30-kDa NH2-terminal domain with an amino acid composition typical of a globular structure and an acidic COOH-terminal domain rich in proline, serine, threonine, and alanine. This is consistent with proteolysis experiments that suggested that AP-3 could be divided into a 30-kDa globular uncharged clathrin-binding domain and an acidic, anomalously migrating domain.

Adaptor Proteins, Vesicular Transport↗
PubMed1993

Financing health care in rural China: preliminary report of a nationwide study.

One unforeseen consequence of the change from collective to household production in rural China has been that the financial basis of the rural health services has been eroded. The majority of peasants now pay for health care on a fee-for-service basis. A major initiative aimed at the establishment of prepayment schemes for funding rural health services is underway. A nationwide survey which compared health utilization and expenditure under different financing mechanisms was carried out in 1988. This paper presents the preliminary findings of that study. There is evidence that hospital charges were a barrier to inpatient care for those not covered by an insurance scheme. The data were less clearcut with regard to access to outpatient care. There is a need for further study which focuses on poor households and those living in remote villages. The study found that drug charges are an important source of revenue for the rural health services. The impact of this on prescription practices is an area which requires additional research. The cost of rural health services was relatively low. It is feasible to finance them almost entirely out of local resources in the more developed regions. The situation in the poorer provinces is more complicated. In spite of the fact that average health expenditure was almost 5% of household income in 1988, there was evidence of lack of access. This suggests that it may be more difficult to develop prepayment schemes to cover the full range of rural health services in the less developed regions.

China↗
PubMed1993

Analysis of lectin receptors in normal nasal mucosa, nasal polyp, inverted papilloma and papillary adenocarcinoma.

In order to investigate the changes in glycoprotein structure in the process of cellular differentiation of the nasal mucosa, formalin-fixed, paraffin-embedded biopsy specimens of normal nasal mucosae, nasal polyps, inverted papillomas and papillary adenocarcinomas were analysed by the Avidin Biotin-Peroxidase Complex technique for the demonstration of peanut agglutinin (PNA) receptors, concanavalin ensifomis agglutinin (ConA) receptors, ulex europeaus agglutinin (UEA-I) receptors, wheat germ agglutinin (WGA) receptors, carcino-embryonic antigen (CEA) and keratin. The quantity and distribution of PNA receptors, ConA receptors, UEA-I receptors and CEA were different, in relation to the varying pathological changes. The results suggest that the glycoprotein structure in the cells of the nasal mucosa will change following their differentiation and malignant transformation, which may be helpful in establishing the diagnosis.

Adenocarcinoma, Papillary↗
PubMed1993

Microsurgical replantation of the avulsed scalp: report of six cases.

This article reports the successful microsurgical replantation of six scalps avulsed for over 3 to 11 hr, after trauma and before repair, including five total and one partial avulsion. The authors believe that one key to successful replantation is effective vessel anastomoses. In the reported series, three scalps were reconstructed with two superficial temporal vessels and in five cases, with a 1:1 ratio between arteries and veins. The partially avulsed scalp was replanted successfully with only one artery and one vein. The management of postoperative complications is discussed.

Accidents, Occupational↗
PubMed1993

Molecular cloning and characterization of dTAFII30 alpha and dTAFII30 beta: two small subunits of Drosophila TFIID.

The multisubunit transcription factor TFIID is an essential component of the RNA polymerase II initiation apparatus. Recent studies suggest that TFIID subunits, or TAFs associated with the TATA-binding protein (TBP), play a critical role in modulating transcriptional activation by sequence-specific DNA-binding factors. Thus far, six of the largest TAFs associated with Drosophila TFIID have been cloned and partially characterized. Here, we report the molecular cloning, expression, and subunit interaction specificities of two small molecular mass TAFs. Both dTAFII30 alpha and dTAFII30 beta are associated with TFIID via interactions with other TAFs, including dTAFII250, dTAFII150, and dTAFII110. In addition, dTAFII30 alpha also contacts dTBP. The carboxy-terminal half of dTAFII110 was found to contact a short 67-amino-acid region of dTAFII30 alpha, which is predicted to form two potential alpha-helices, one of which is amphipathic. Interestingly, dTAFII30 alpha also appears to multimerize through its carboxy-terminal region. Although neither dTAFII30 alpha nor dTAFII30 beta have been found to interact with specific activators thus far, it is intriguing that both bind other TAFs such as dTAFII110 and dTAFII150, which are the targets of activation domains. Our studies suggest that both of the small subunits of TFIID play a role in the assembly of the complex and may contribute to the stability of multiple TAF-TAF interactions.

Amino Acid Sequence↗
PubMed1993

A micromolar pool of antigenically distinct precursors is required to initiate cooperative assembly of hepatitis B virus capsids in Xenopus oocytes.

Assembly of hepatitis B virus capsid-like (core) particles occurs efficiently in a variety of heterologous systems via aggregation of approximately 180 molecules of a single 21.5-kDa core protein (p21.5), resulting in an icosahedral capsid structure with T = 3 symmetry. Recent studies on the assembly of hepatitis B virus core particles in Xenopus oocytes suggested that dimers of p21.5 represent the major building block from which capsids are generated. Here we determined the concentration dependence of this assembly process. By injecting serially diluted synthetic p21.5 mRNA into Xenopus oocytes, we expressed different levels of intracellular p21.5 and monitored the production of p21.5 dimers and capsids by radiolabeling and immunoprecipitation, by radioimmunoassay, or by quantitative enzyme-linked immunosorbent assay analysis. The data revealed that (i) p21.5 dimers and capsids are antigenically distinct, (ii) capsid assembly is a highly cooperative and concentration-dependent process, and (iii) p21.5 must accumulate to a signature concentration of approximately 0.7 to 0.8 microM before capsid assembly initiates. This assembly process is strikingly similar to the assembly of RNA bacteriophage R17 as defined by in vitro studies.

Animals↗