Biomedical subjects

C Zhao

Publications and source records attributed to C Zhao.

At least 217 records · Page 12Linked to original sources

PubMed1995

Immunocytochemical localization of prostaglandin E2 receptor subtypes in porcine ocular tissues. I. Uveal tissues.

Polyclonal antibodies were raised against 15-residue sequences in the carboxyl terminal region of mouse EP1, EP2, and EP3 subtypes. The selected sequences are well conserved in different species. Using the antibodies, the localization of the receptor subtypes in porcine uveal tissues was investigated by immunoperoxidase reaction (by light microscopy) and immunogold labeling (by electron microscopy). EP1 immunoreactivity was found in ciliary nonpigmented epithelium and iris muscles (both sphincter and dilator). EP2 was localized to ciliary nonpigmented epithelium and muscle, iris sphincter muscle, and trabecular meshwork. EP3 immunoreactivity was detected in all uveal tissues examined.

Amino Acid Sequence↗

PubMed1995

Immunocytochemical localization of prostaglandin E2 receptor subtypes in porcine ocular tissues. II. Nonuveal tissues.

The localization of PGE2 receptor subtypes (EP1, EP2 and EP3) in nonuveal tissues of porcine eye was investigated by immunocytochemical methods with polyclonal antibodies directed against conserved peptide sequences in the carboxyl terminal region of the receptor subtypes. EP1 was found only in corneal epithelium, while EP2 immunoreactivity was associated with corneal epithelium and endothelium and lens epithelium. EP3 receptor subtype was localized to all ocular tissues examined (except lens fiber cells), i.e. corneal epithelium and endothelium, lens epithelium, retinal photoreceptor and pigmented epithelium, Bipolar cell, horizontal cell, amacrine cell, ganglion cell and Muller cell.

Animals↗

PubMed1995

Chemopreventive effects of calcium but not aspirin supplementation in cholic acid-promoted colon carcinogenesis: correlation with intermediate endpoints.

Epidemiological studies have suggested that increased intake of calcium (Ca) or aspirin (ASA) is associated with a reduced risk for colon cancer. To delineate a possible mechanism of action, the present study used male F344 rats in an azoxymethane (AOM)-induced colon tumor model to study the single and interactive effects of Ca and ASA on cholic acid-promoted experimental colon carcinogenesis. Following initiation with AOM, a promotion diet containing 0.5% cholic acid was fed for 34 weeks until the adenoma development stage. Cholic acid was used as a surrogate for high-fat diets and to promote carcinogenesis. Diets were supplemented with CaCO3 (2% Ca by weight), 250 p.p.m. ASA, or both. After 34 weeks, the diets were switched during the progression stage and rats were killed at week 51. Several intermediate endpoints were examined during the course of AOM carcinogenesis to determine their reliability as predictors of colon cancer risk. Intermediate endpoints included colon crypt height measurement, colon mucosal ornithine decarboxylase (ODC) and colon mucosal protein kinase C (PKC) activities. The biomarkers were examined at the beginning of the study at 2 weeks, and thereafter at 5, 15, 30 and 40 weeks of dietary treatment. Animals were necropsied at week 51 and tumor incidence and numbers were analyzed for correlation with biomarkers. Survival was highest in the group fed CaCO3 during the promotion stage and tumor burden was lowest in groups fed CaCO3 during this stage. Supplementation during the progression stage was ineffective. The cholic acid promotion model resulted in increased ODC which was inhibited by intervention during the promotion stage with Ca, but not ASA. PKC was also activated by cholic acid feeding, and this effect was modulated by intervention in the promotional stage with Ca or ASA. Colon tumor incidence and burden was increased by cholic acid promotion and decreased by Ca, but not affected by ASA. In summary, Ca is a more effective chemopreventive agent in cholic acid-promoted colon carcinogenesis than ASA, impacting both incidence and tumor number. Colonic ODC, but not PKC may be a suitable predictor of risk and response in chemoprevention trials for colon cancer.

Animals↗

PubMed1995

Non-promoting effects of lean beef in the rat colon carcinogenesis model.

Recent epidemiologic studies have implicated red meat consumption as a risk factor for colon cancer in both men and women. However, it has been very difficult to separate the effects of meat as a protein source from the accompanying fat content of the diets analyzed in these studies. Experimental data from rodent feeding trials show mixed results, with no firm conclusions being possible in terms of the colon-cancer promoting effects of meat fat. The goal of the present study was to compare, in an experimental animal model, the effects of beef with casein as a protein source, within the context of a low- and high-fat diet containing either corn oil or beef tallow, on promotion of colon carcinogenesis. Tumors were induced in Sprague-Dawley rats with 1,2-dimethylhydrazine (20 mg/kg body wt for 10 weeks). Two hundred and eighty male weanling rats were randomized to eight dietary treatment groups of a 2x2x2 factorial design with fat source (corn oil vs. beef tallow), fat level (5% vs. 20%), and protein source (very lean beef vs. casein) as the factors. Diets were fed ad libitum before, during and after carcinogen treatment for a total of 27 weeks. At termination of the study, animals were examined for location, size and type of colon or extracolonic lesions. The total incidence and number of colon tumors were significantly lower in the groups fed beef rather than casein. High fat levels, regardless of source, significantly increased the number of colon adenomas. These results demonstrate that when lean beef is used as the protein source in the context of a low-fat diet, fewer intestinal tumors develop. These data do not support the belief that red meat consumption increases the risk for colon carcinogenesis, but underscores the importance of fat level in dietary context.

1,2-Dimethylhydrazine↗

PubMed1995

The effects of prostaglandins E2 and F2 alpha on porcine ciliary muscle cells in culture.

The purpose of this work is to investigate the effect of prostaglandins (PGs) on the contraction of ciliary muscle cells. It has been proposed that PGs induce relaxation of ciliary muscle and facilitate uveoscleral outflow, and reduce intraocular pressure (IOP). The ocular response to PGs is complicated because the relative contributions of uveoscleral flow and the conventional outflow to lowering IOP and the type of PG receptors associated with ciliary muscle may vary depending on animal species. In order to obtain insights into prostaglandin receptors of ciliary muscle, ciliary muscle cells from porcine eye were grown in culture and characterized immunocytochemically with antibodies against smooth muscle-alpha-actin and PGE2 receptor subtypes. As in ciliary muscle tissues, positive immunostaining for alpha-actin and EP2 and EP3 subtypes was observed in cultured cells. Time-dependent contraction of cultured cells induced by 10(-4) M carbachol was recorded by taking sequential photographs and analyzed. Using this assay method, the effect of prostaglandins E2 and F2 alpha to inhibit the carbachol-induced contraction was studied. PGE2 showed potent inhibition of cell contraction; 10(-7) approximately 10(-8) M PGE2 inhibited 50% of full contraction in 15 min. PGF2 alpha at 10(-4) M neither caused cell contraction by itself nor blocked carbachol-induced contraction. The EP2 agonist 11-deoxy-16, 16-dimethyl PGE2 at 10(-4) M inhibited cell contraction but the EP3 agonist sulprostone had no effect. Dibutyryl cAMP at 3 x 10(-5) M inhibited contraction by 50%. In the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX), less than 10(-7) M dibutyryl cAMP caused 50% inhibition. In support of the cAMP effect, the addition of 10(-4) M PGE2 to cultured cells in the presence of indomethacin and IBMX was shown to cause an 80% increase in intracellular cAMP concentration compared with the basal (i.e. unstimulated) level of cAMP. Stimulation of cells with 10(-4) M PGF2 alpha caused no increase in cellular cAMP. These results indicate that PGE2 receptor EP2 subtype, but not PGF2 alpha receptor, is involved in the inhibition (hence relaxation by inference) of carbachol-induced porcine ciliary muscle cell contraction. It awaits further studies to determine whether cultured ciliary muscle cells of other species respond similarly to different PGs.

1-Methyl-3-isobutylxanthine↗

PubMed1995

[Isolation and identification of Rhodopseudomonas viridis and Rhodopseudomonas sulfoviridis].

Under selective culture conditions, two pure cultures (strain G and strain SG) of the purple nonsulfur photosynthetic bacteria containing bacteriochlorophyll b were isolated from pulp effluent and sludge of sewage treatment plant by means of agar shake dilution. Although the cells of strain G and strain SG contained bacteriochlorophyll b and carotenoids, intra-cytoplasmic membranes were of lamellar type parallel to cytoplasmic membrane, the two strains differ in using various organic carbon sources, depending on reduced sulfur compounds and assimilate sulfate. According to Bergey's Manual of Systematic Bacteriology Volume 3, strain G was identified to be Rhodopseudomonas viridis,, strain SG was identified to be Rhodopseudomonas sulfoviridis.

China↗

PubMed1995

An immunocytochemical study on relations between mast cell and peptidergic terminals in nasal mucosa of chronic rhinitis patients.

Mast cell-nerve relation is a new topic explored deeply in different organs, but little documentation could be found in the literature on the relation in human nasal mucosa. We carried out this study using immunocytochemistry and found that substance P (SP) terminals were present in human nasal mucosa from six cases of chronic rhinitis. SP terminals were often found to be adjacent to or have a direct contact with mast cells (MCs). Electron-microscopic studies revealed that MCs could contact nonmyelinated nerve terminals. These results have important implications in the understanding of the pathogenesis of neurogenic inflammation seen in nasal mucosa and will probably cast new insight into the future treatment of such disease.

Adult↗

PubMed1995

Electric acupuncture treatment of peripheral nerve injury.

54 cases of peripheral nerve injury were treated by electric acupuncture and compared with 54 control cases treated with supportive medication. The changes after treatment were observed chiefly by electromyography while sensory and motor improvement were also recorded as auxiliary indicators. The therapeutic results in the acupuncture group were 5 cases cured, 26 markedly effective, 19 improved, and 4 cases failed, a total effective rate of 92.6% in contrast to the 55.6% for the controls. Analysis of the therapeutic results showed that 1) those in the acupuncture group were significantly better than in the control group; 2) nerve injuries should be treated as early as possible; 3) the radial nerve and the common peroneal nerve recovered faster than others; 4) cases not surgically explored recovered faster than those that were, and 5) patients with prompt propagation of the needling sensation recovered significantly faster than those with slow propagation.

Acupuncture Therapy↗

PubMed1995

[Distribution of calcitonin gene-related peptidergic terminals in rat nasal mucosa].

The distribution of calcitonin gene-related peptidergic (CGRP) terminals in rat nasal mucosa was observed with immunocytochemistry technique (ABC method). The results showed that CGRP-ergic terminals had extensive localizations along the walls of arterioles and venules, around the acini of glands and between the epithelial cells, with the walls of arterioles having highiest densities of such terminals. The typical morphology of CGRP-ergic terminals was one of multistage branched fibers in the form of rosary varicosities. CGRP immunoreactive neurons were also present in trigeminal ganglion (TG). Based on our observations, it is suggested that CGRP-ergic terminals in rat nasal mucosa are the peripheral fibers originating from the ganglion cells in TG. These fibers may be involved in the perception of local mucosal stimuli and propagation of neural impulses to the central terminals and will then release CGRP in the brain stem. There is also possibility that CGRP may be peripherally released in nasal mucosa and exerts influences on mucosal functions.

Animals↗

PubMed1995

Expression of human interleukin-11 cDNA in E. coli.

A 551-bp hIL-11 gene fragment that includes no nucleotide sequences encoding signal polypeptide and the initial 8 amino acids of the mature protein was cloned into a high-level expression vector pEx31B of E. coli. The authors identified the recombinant plasmid, designated pEx31-IL11, by restriction endonucleases digestion and DNA sequencing. The resulting recombinant plasmids were then used to transform E. coli strain HB101, and expression in the PL promoter system, which is temperature-regulated, was achieved. The expressed fusion protein amounts to 50% of total bacterial proteins. The hIL-11 protein expressed in E. coli was fused to the N-terminal 99 amino acids of the MS2 polymerase to form the inclusion body. These recombinant proteins can be purified to about 80% by extracting inclusion body with urea. One IL-6-dependent cell line 7 TD1 was used for bioassay. The recombinant hIL-11 protein was preliminarily purified and renatured to a specific activity of 10(5)U/mg, even in the presence of an excess of a neutralizing anti-IL-6 antibody.

DNA, Complementary↗

PubMed1995

[False dysphagia caused by omohyoid muscle syndrome: 50 cases of autopsy and 2 cases of clinical reports].

Omohyoid muscle syndrome is rarely seen clinically. A mass can be seen on the neck while swallowing, and the patient feels discomfort and dysphagia. The mass disappears immediately after swallowing and you can't find the mass by palpation. We made autopsies in 50 cases of omohyoid muscle syndrome, and observed muscles, especially the intermediate tendons, sheaths of tendon and projection of omohyoid muscles. The restriction and regulatory functions of intermediate tendon sheaths during contraction of the omohyoid muscles were briefly explained. By combination with 2 cases of clinical reports, also investigated. We also investigated the etiology of omohyoid muscle syndrome.

Adult↗

PubMed1995

[Studies on regulatory effects of acupuncture on mucosal secretory IgA in patients with allergic asthma].

We studied mucosal SIgA immunity of patients with allergic asthma treated by acupuncture. Our results showed that concentrations of SIgA and total IgA in saliva (P < 0.01, < 0.02) and in nasal secretions (P < 0.02, < 0.02), and levels of IgE in sera (P < 0.001) from patients with allergic asthma were significantly decreased after treatment with acupuncture. The results suggested that attacks of delayed and immediate allergic asthma could be effectively inhibited by acupuncture. The facts that there were no significant changes in IgA in supernatants of peripheral blood lymphocytes stimulated with PWM of patients with allergic asthma after treated by acupuncture were associated with regulation of negative feedback of T-lymphocyte expressing IgA-R and it released bound factor of IgA in production of polymeric IgA.

Acupuncture Therapy↗

PubMed1995

Cloning, expression and purification of the ligand-binding region of human IL-6R in E. coli and its preliminary functional identification.

The ligand-binding region of human IL-6R is taken as the target gene fragment to be cloned and expressed. With pET-3b as expressing vector, two recombinants pET-6R(B) and pET-6R(B)4 have been constructed encoding the ligand-binding region (28 kD) of hIL-6R and its dimmer (53 kD), respectively. After induction with IPTG, they produced two proteins rIL6R-28 of 28 kD and rIL6R-53 of 53 kD amounting to 50% and 30% of total bacteria proteins, respectively. The expressed products were mainly recovered as inclusion bodies. After purification and renaturation, both of them were capable of augmenting the growth-stimulating effect of IL-6 on 7TD1 cells, an IL-6 dependent cell line. The result of ELISA also revealed that both rIL6R-28 and rIL6R-53 had the obvious ligand-binding activity.

Antigens, CD↗

PubMed1995

The role of recombinant human fusion protein IL-6/IL-2 (CH925) in hepadna virus infection treatment.

The effects of CH925, a novel immune modulator, on hepadna virus infection was evaluated. Day-old ducklings were inoculated intravenously with LJ-76 DHBV containing serum. Infected ducklings were then treated with the CH925 and the mixture of IL-2 and IL-6 intravenously and the control ducklings received equivalent normal saline (NS). Blood and liver samples were taken and assayed for DHBV DNA and/or DHBsAg. At the completion of the experiment there was a inhibition of viremia with the CH925 and IL-2 + IL-6. Serum DHBV DNA was detected in 6 of 10 ducks in 100,000 unit/kg dosage group, 7 of 10 ducks in 50,000 unit/kg dosage group and 6 of 10 ducks in IL-2 + IL-6 dosage group, compared with 9 of 10 NS control, and it showed a similar result in circulating DHBsAg. When samples of liver DNA were processed for hybridization, a little difference in the DHBV DNA replication was noted between ducks receiving CH925, IL-2 + IL-6 or NS placebo. It is suggested that CH925 might be a potential remedy in HBV infection treatment.

Animals↗

PubMed1995

[Measurement of Ca2+ concentration and endocochlear potential in experimental endolymphatic hydrops in vivo].

This study was based on observations on 14 normal guinea pigs and 17 guinea pigs in which the left endolymphatic duct and sac had been surgically obliterated to induce endolymphatic hydrops. Three groups of hydropic animals were tested 1, 2 and 3 months after surgery. The Ca2+ concentration and endocochlear potential (EP) were recorded by means of double-barrelled ion selective micro-electrode in the third turn of the cochlea. The results indicated that a decrease in EP and an increase in Ca2+ in hydropic cochlea, a negative correlation was present. In the control ear, the values of Ca2+ and EP were 26.4 +/- 0.33 microns/L (n = 14) and 72.78 mV (n = 14), respectively; in the hydropic ear, the value of Ca/+ was 404.47 +/- 79.74 microns/L (n = 17), while the EP was 55.82 +/- 3.28 mV (n=17). According to Nerstian formula, the slope of electrochemical gradient in the control was 31 mV/decade (n = 14), but in the hydropic ear it increased to 72.5 mV/decade change in Ca2+ (n = 17). The statistical analysis showed significant difference between the control and hydropic ears. The changes were progressive and became more pronounced as the duration of hydrops prolonged. The cause of hearing loss in the Ménière's disease and the relation between the EP and CA2+ concentration had been discussed.

Animals↗

PubMed1995

[Management of the dry eye with parotid duct transplantation: a summary on 40 cases].

PURPOSE: As today the effect of parotid duct transplantation is clinically regarded as uncertainty, and there is still absent of effective managenent of the dry eye, this paper tries to clarify its value, and see if it can be used clinically. METHODS: Forty dry eyes were operated with a follow up of 3 weeks to more than 6 years in the past 42 years. The pre- and postoperative changes of tear flow and vision, and the cause of dry eye, operative method, length of parotid duct and complications of bilateral operation were briefly summarized. RESULTS: Of these 40 operated eyes postoperatively, 82.5% had tearing, but no tearing occurred in 27.5%. Finally: vision increased in 72.5% with out any decrease. There was no difference in the results whether the procedure done extraorally or intraorally. The parotid duct being shorter was only seen in 7.5%, which were satisfactorily managed by tube making with oral mucosa. Four cases operated binocularly and silmutaneously, only 1 occurred aveolar abscess with complaining dry mouth, but cured 1 week later. After operation, profusive tearing occurred in 25 dry eyes caused by trachoma during eating and 96% usually, but tearing stopped finally in 3 eyes (2, due to infection). Four dry eyes with ocular pemphigoid failed. Among 9 dry eyes resulted from Stevens-Johnson syndrome, 6 had little tearing postoperatively, 2 of which attained a nearly normal results. One of the two dry eyes resulted from alkali eye burn failed and the other, occurred tearing but only followed-up for 1 month, the result was uncertain. CONCLUSION: As the technique of the parotid duct transplantation is simple and easy with no much complications, and for treating the dry eye, there is up to now still absent of effective management, therefore, the parotid duct transplantation should be considered to be indicated in dry eyes esp, caused by Stevens-Johnson syndrome. Though its success rate is lower than that of traucomatous ones, the satisfactory result of nearly normal postoperative tearing may be got. In ocular pemphigoid, however, it is contraindicated.

Follow-Up Studies↗

PubMed1994

A recombinant DNA bio-assay for selenium in blood.

The trace element selenium (Se) is included in the form of selenocysteine (Sec) at the active site of several prokaryotic and eukaryotic proteins known as selenoproteins (SePro). The growing implications of SePro in cell physiology and human health point to the need for an adequate means of assessing Se status in biological fluids. Here, we describe a new approach based on a recombinant DNA construct, in which the expression of the 'lacZ gene in Escherichia coli is proportionally and specifically driven by UGA-directed Sec incorporation. Se status is determined in samples of rat blood first treated by acid hydrolysis for protein degradation. As compared to other methods, this simple, sensitive bioassay (BIO) for determining Se status seems to be unique in its ability to measure all functional Sec residues in SePro in blood serum.

Animals↗

PubMed1994

Suppressors of the Ca(2+)-sensitive yeast mutant (csg2) identify genes involved in sphingolipid biosynthesis. Cloning and characterization of SCS1, a gene required for serine palmitoyltransferase activity.

Suppressor mutations in Saccharomyces cerevisiae that block Ca(2+)-induced death of csg2 mutant cells were investigated. These mutants, called scs mutants (suppressor of Ca2+ sensitivity), fall into seven complementation groups (scs1-scs7). All mutant strains in two of the complementation groups (scs1 and scs2) simultaneously acquire a requirement for 10 mM Ca2+, whereas wild type grow with only trace amounts of Ca2+. SCS1 was cloned by complementation of its Ca(2+)-requiring phenotype and found to be homologous to a family of pyridoxal phosphate enzymes that catalyze acyltransfer reactions. Secondary phenotypes of the scs1 mutants indicate that SCS1 is required for serine palmitoyltransferase activity which catalyzes the first committed step in sphingolipid biosynthesis (palmitoyl-CoA + serine-->3-ketosphinganine+CoASH+CO2). Other scs mutants as well as the csg2 null mutant have altered sphingolipid metabolism. The data suggest that sphingolipid metabolism in yeast is either regulated by Ca2+ and/or is required for Ca2+ homeostasis.

Acyltransferases↗