Biomedical subjects

C Zhao

Publications and source records attributed to C Zhao.

At least 127 records · Page 7Linked to original sources

PubMed1999

Lipophilins: human peptides homologous to rat prostatein.

Lipophilin components A, B and C are human homologues of prostatein, the major secreted protein of rat prostate. This report describes their cDNA sequences, tissue expression and chromosomal localization. Lipophilin gene products were widely expressed in normal tissues, especially in endocrine-responsive organs. The gene for lipophilin C (also called mammaglobin b) is located on chromosome 11q12-q13.1, near the mammaglobin gene, a homologue overexpressed in many breast cancers. The lipophilin B gene resides on chromosome 10q23, a region deleted in many tumors, and the lipophilin A gene is on chromosome 15q12-q13.

Amino Acid Sequence↗

PubMed1999

Patterning of Caenorhabditis elegans posterior structures by the Abdominal-B homolog, egl-5.

The Caenorhabditis elegans body axis, like that of other animals, is patterned by the action of Hox genes. In order to examine the function of one C. elegans Hox gene in depth, we determined the postembryonic expression pattern of egl-5, the C. elegans member of the Abdominal-B Hox gene paralog group, by means of whole-mount staining with a polyclonal antibody. A major site of egl-5 expression and function is in the epithelium joining the posterior digestive tract with the external epidermis. Patterning this region and its derived structures is a conserved function of Abd-B paralog group genes in other animals. Cells that initiate egl-5 expression during embryogenesis are clustered around the presumptive anus. Expression is initiated postembryonically in four additional mesodermal and ectodermal cell lineages or tissues. Once initiated in a lineage, egl-5 expression continues throughout development, suggesting that the action of egl-5 can be regarded as defining a positional cell identity. A variety of cross-regulatory interactions between egl-5 and the next more anterior Hox gene, mab-5, help define the expression domains of their respective gene products. In its expression in a localized body region, function as a marker of positional cell identity, and interactions with another Hox gene, egl-5 resembles Hox genes of other animals. This suggests that C. elegans, in spite of its small cell number and reproducible cell lineages, may not differ greatly from other animals in the way it employs Hox genes for regional specification during development.

Animals↗

PubMed1999

Comparison of (32)P-postlabeling and high-resolution GC/MS in quantifying N7-(2-Hydroxyethyl)guanine adducts.

This study compares (32)P-postlabeling and high-resolution gas chromatography/mass spectrometry (GC/MS) in the quantification of N7-(2-hydroxyethyl)guanine adducts (7-HEG) in DNA obtained from the same tissue samples of control rats and rats exposed to ethene. The samples were obtained from two independent studies. In one study, male Sprague-Dawley rats were exposed to 300 ppm ethene for 12 h/day for 3 days ("Euro samples"). In the other study, male F-344 rats were exposed to 3000 ppm ethene for 6 h/day for 5 days ("U.S. samples"). DNA from liver and kidney from the European study was isolated in the European laboratory, and DNA from liver and spleen from the U.S. study was isolated in the U.S. laboratory. The DNA samples were coded, divided into two portions, and exchanged between the two laboratories. All DNA samples from both laboratories were analyzed with respect to 7-HEG adducts by (32)P-postlabeling and high-resolution GC/MS in the European and U.S. laboratories, respectively. However, the U.S. samples were repurified in the European laboratory before the postlabeling analysis. The data from the Euro and the U.S. samples were therefore treated separately in the regression analysis of the (32)P-postlabeling versus GC/MS data. The slope of the regression line for the Euro samples was 1.19 (r = 0.97), implying that the GC/MS data were slightly lower than the postlabeling data (one possible outlier was excluded). The slope of the regression line for the U.S. samples was 0.61 (r = 0.94), implying that the GC/MS data were somewhat higher than the postlabeling data. The main conclusion from this study is that there is very good agreement between the (32)P-postlabeling and high-resolution GC/MS methods in quantifying 7-HEG adducts to DNA, particularly when identical DNA samples are analyzed and the RNA content is <2%. The paper also discusses the background levels of adducts, the interorgan distribution, comparison between different strains, and exposure conditions.

Animals↗

PubMed1999

Differential expression of caprine beta-defensins in digestive and respiratory tissues.

We identified two novel beta-defensin precursors, preproGBD-1 and preproGBD-2, in the tissues of a goat. Although the precursors were identical in 96.8% of their bases and 88.2% (60 of 68) of their amino acids, preproGBD-1 was expressed principally in the tongue and respiratory tract, whereas preproGBD-2 expression predominated throughout the intestine. These findings exemplify the phenomenon of tissue-specific expression in a family of host defense peptides that arose before the avian and mammalian lineages diverged.

Amino Acid Sequence↗

PubMed1999

Purification and properties of proline-rich antimicrobial peptides from sheep and goat leukocytes.

We purified three proline-rich antimicrobial peptides from elastase-treated extracts of sheep and goat leukocytes and subjected two of them, OaBac5alpha and ChBac5, to detailed analysis. OaBac5alpha and ChBac5 were homologous to each other and to bovine Bac5. Both exhibited potent, broad-spectrum antimicrobial activity under low-concentration salt conditions. While the peptides remained active against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Listeria monocytogenes in 100 mM NaCl, they lost activity against Staphylococcus aureus and Candida albicans under these conditions. ChBac5 was shown to bind lipopolysaccharide, a property that could enhance its ability to kill gram-negative bacteria. Proline-rich Bac5 peptides are highly conserved in ruminants and may contribute significantly to their innate host defense mechanisms.

Amino Acid Sequence↗

PubMed1999

[Effects of human papillomavirus infection on pregnant women and chorionic trophoblasts].

OBJECTIVE: To evaluate the effects of human papilloma virus (HPV) infection on pregnant women and chorionic trophoblasts. METHODS: The morphological characters were observed from 62 pregnant women with codyloma acuminatum during the first and second trimester. In situ hybridization (ISH) was performed to detect HPV 6/11 in chorionic villi of all these cases. In 10 cases, ISH was also performed in condyloma acuminatum of vulva, vaginal and cervix. In 10 cases HPV 6/11 was detected by polymerase chain reaction (PCR) in chorionic villi as well. RESULTS: The lesions condyloma acuminatum developed rapidly during pregnancy. Multiple lesions were found usually, and the gross appearances and histological features were more typical. Using ISH and PCR to detect HPV 6/11-DNA in chorionic villi all showed negative. 8 of 10 cases were positive in condyloma acuminatum sites by ISH. CONCLUSIONS: HPV infection does not make vertical transmission during first and second trimester. It does not increase the potential risk for the fetus.

Adult↗

PubMed1999

[The effects of inhaled bronchodilators on central inspiratory drive in patients with COPD].

OBJECTIVE: To evaluate the effects of inhaled bronchodilators on the central inspiratory drive in patients with COPD. METHODS: 91 patients with COPD were divided into three groups (A, B, C) randomly. Lung functions and P(0.1) were measured at baseline and 20 min and 60 min after inhalation (A: albuterol; B: iprotropium; C: albuterol + iprotropium). RESULTS: P(0.1) decreased after inhalation in all three groups (P < 0.05 approximately 0.001). A positive correlation between DeltaP(0.1) and DeltaFRC was found in the three groups (r = 0.4325 - 0.5230, P < 0.05 approximately 0.01). V(E)/P(0.1) increased in the three groups after inhalation (P < 0.05 approximately 0.005). There was significant improvement of V(E)/P(0.1) in group B and C as compared with that of group A (P < 0.05, P < 0.001); There was a different correlative factor with V(E)/P(0.1) in group B and C. CONCLUSIONS: (1) P(0.1) decreased after inhalation, It may be caused by decreased FRC. (2) V(E)/P(0.1) became appropriate after inhalation in all groups; The improvement in group B and C was superior to that of group A. There may be different mechanisms to improve V(E)/P(0.1) by different inhalators.

Administration, Inhalation↗

PubMed1999

[E-CD expression and its clinical significance in human bladder carcinoma].

OBJECTIVE: To invest the expression of the E-CD protein and its clinical significance in human recurrent bladder transitional cell carcinoma. METHODS: Immunohistological chemistry method was employed to assess the expression of E-CD in 54 cases of bladder transitional cell carcinoma. RESULTS: Decreased E-CD expression correlated with both increased grade and stage (chi(2) = 6.65, P < 0.05; chi(2) = 7.15, P < 0.01). More importantly, abnormal expression of E-CD correlated with the high recurrence in short time and the poor survival (chi(2) = 4.88, P < 0.05; Log-rank test: chi(2) = 4.6, P < 0.05). CONCLUSIONS: The expression of E-CD is an useful parameter of malignancy of carcinoma. The detection of E-CD expression might be significant in determining the malignancy, recurrence and prognosis of bladder transitional cell carcinoma.

Adult↗

PubMed1999

[A study on the biological properties of fimbriae of Actinomyces viscosus. I. The preparation and determination of fimbriae of A. viscosus].

OBJECTIVE: To build up the methods to prepare and determine the fimbriae of A. viscosus. METHODS: Type 1 and 2 fimbriae were prepared from A. viscosus 5519 and 5951 respectively. Fimbriae were isolated from bacteria cells by mechanical shaking, obtained by collecting the supernatant after centrifugation, and purified by ammonium sulfate precipitations and gel filtration. RESULTS: Electron microscope showed that fimbriae existed in the preparations. The immunological reaction between the fimbriae preparations and specific antibodies against fimbriae attested that they were type 1 or type 2 fimbriae. CONCLUSION: The present study become a foundation for further study on the biological properties of fimbriae of A. viscosus.

Actinomyces viscosus↗

PubMed1999

[A study on biological properties of fimbriae of Actinomyces viscosus. II. Chemical characteristics of fimbriae of A. viscosus].

OBJECTIVE: To investigate the chemical characteristics of two purified fimbriae. METHODS: The specific antibodies against type I and type II fimbriae of A. viscosus were prepared and the purity of the two purified fimbriae had been identified by the specific antibodies. Then, chemical analysis and amino acid analysis of the two purified fimbriae were done. RESULTS: The two purified fimbriae were mainly composed of proteins and small amount of carbohydrate. The two types of fimbriae contained large amounts of aspartic acid, glutamic acid, alanine, lysine and glycine, and high percentage of nonpolar amino acid was analysed while basic amino acids were present in a very small amounts. CONCLUSION: These results may help to understand the relationship between the chemical characteristics of two types of fimbriae and their biological activity.

Actinomyces viscosus↗

PubMed1999

[The investigation of the audio-vestibular and oculomotor functions in people more than eighty years old].

OBJECTIVE: To investigate audio-vestibular and oculomotor functions of octogenarian. METHOD: The audition were measured with audiometry and auditory brainstem response. The semicrcular, oculomotor and balance functions were examinated by electronystagmography and posturography. RESULT: 1. The hearing abnormality of speech frequency were 84.1 percent by audiometry; 2. The abnormal rats of semicircular function and posturogram were 38.5% and 74.4% respectively. The body sway locus and velocity of octogenarians have increased as compared with the group of 60 years old in the posturography; 3. The latency of saccade was prolonged and total hearmonic distortion of pusuit was increased than that of 60 years old in the oculomotor test. CONCLUSION: The easily falling of octogenarians may be related to disturbing of semicircular oculomotor and equilibrational functions.

Age Factors↗

PubMed1999

[Changes of Ca(2+)-ATPase in the cochlea of guinea pig during labyrinthine hydrop].

OBJECTIVE: To investigate the localization of Ca(2+)-ATPase (Ca2+ pump) in the cochlea and its change in labyrinthine hydrops. METHODS: The left endolymphatic sac was ablated to induce endolymphatic hydrops in fourteen healthy guinea pigs after the sliver ball electrode was placed on the round window. The Ca(2+)-ATPase was studied by the lead citrate reaction in the control and hydropic ears. The reaction product was lead phosphate particles as an expression of Ca(2+)-ATPase activity under the electron-microscope. RESULTS: The Ca(2+)-ATPase activity was found mainly on the endolymphatic surface of the Reissner's membrane, the stereocilia and cuticular plate of inner and outer hair cells, as well as along the infolding plasma membrane of the strial intermediate cells. The Ca(2+)-ATPase activity was significantly decreased during endolymphatic hydrops in the above-mentioned locations. CONCLUSION: The response thresholds of filtered click were increased and the Ca(2+)-ATPase significantly decreased in the cochlea during labyrinthine hydrops. These results suggest that correlation exists between the CAP threshold and the activity of Ca(2+)-ATPase in the model of labyrinthine hydrops.

Animals↗

PubMed1998

32P-postlabelling of N6-adenine adducts of epoxybutanediol in vivo after 1,3-butadiene exposure.

Epoxybutanediol is one of the epoxide metabolites of butadiene (BD). A pair of diastereomeric N-1-adenine adducts were formed by reacting epoxybutanediol with deoxyadenosine 5'-monophosphate (5'-dAMP). These two N-1-adenine adducts rearranged in a base-catalysed reaction to an N6-trihydroxybutyl-adenine adduct, which was characterized by UV and mass spectroscopy. Using the 32P-postlabelling/HPLC assay the same adducts were detected in diepoxybutane (DEB)-treated DNA in vitro and in liver DNA samples from rats exposed to BD by inhalation. Adenine adducts of epoxybutanediol are probably suitable for monitoring BD exposure.

Animals↗

PubMed1998

Structure and mapping of the human beta-defensin HBD-2 gene and its expression at sites of inflammation.

We cloned a second human beta-defensin gene, HBD-2, and determined its gene structure and expression in inflamed tissue sections. The entire gene spanned about 2 kb with two small exons and one intron. Radiation hybrid studies confirmed the location on chromosome 8p, were consistent with the order HNP-1, HBD-1 and HBD-2, and located HBD-2 as the most centromeric of the genes. By three-color fluorescence in situ hybridization on both free chromatin fiber mapping and interphase mapping, HBD-1, HBD-2 and HNP-1 were mapped to chromosome 8p23. HBD-1 was within 40-100kb of HNP-1, while HBD-2 was about 500-600 kb from HBD-1, with the most likely order HNP-1, HBD-1, HBD-2. The expression of HBD-2 was locally regulated by inflammation. HBD-2 mRNA was markedly increased in the epidermis surrounding inflamed regions, but not detectable in adjacent non-inflamed areas, a distribution that was confirmed at the peptide level by immunostaining with HBD-2 antibody. The HBD-2 gene is the first member of the human defensin family that is locally inducible by inflammation.

Base Sequence↗

PubMed1998

Impairment of long-term potentiation and paired-pulse facilitation in rat hippocampal dentate gyrus following developmental lead exposure in vivo.

Neonatal rats were exposed to lead from parturition to weaning via the milk of dams drinking 0.2% lead acetate solution. The alterations of long-term potentiation (LTP) and paired-pulse facilitation (PPF) of hippocampal dentate gyrus in adult rats (90-115 days) following developmental lead exposure were studied in vivo. Input/output (I/O) function, paired-pulse facilitation (PPF), excitatory postsynaptic potential (EPSP) and population spike (PS) amplitude were measured in the dentate gyrus (DG) in response to stimulation applied to the lateral perforant path. The results showed that LTP was induced in control rats with an average PS potentiation of 321.1+/-50.0% (n=18), which was significantly greater than the increase in PS potentiation (173.5+/-30.0%, n=17, p<0.001) in lead-exposed rats after tetanizing stimulation. The mean EPSP potentiation increased to 172.4+/-27.0% (n=18) in control and 138.8+/-21.4% (n=17) in lead-exposed rats after tetanizing stimulation. The lead-induced impairment of LTP of PS potentiation was more serious than that of EPSP potentiation. Following pairs stimulation of perforant fiber at 250 microA and an interpulse interval (IPI) of 10-1000 ms, the average peak facilitation of PS was 211.3+/-25.0% (n=13) in control and 187.7+/-23.0% (n=11) in lead-exposed rats. The average facilitation period duration of PS was 243.0+/-35.8 ms (n=13) in control and 138.0+/-24.4 ms (n=11) in lead-exposed rats. These results suggested that developmental lead exposure in neonatal rats caused impairments in LTP and PPF of hippocampal dentate gyrus.

Animals↗

PubMed1998

Overexpression of lactate dehydrogenase A attenuates glucose-induced insulin secretion in stable MIN-6 beta-cell lines.

Since islet beta-cells express little L-lactate dehydrogenase (LDH) activity, we have examined the effects on these cells of LDH overexpression. In mock-transfected MIN6 beta-cells, LDH activity was 38 nmol/min/mg protein, and 30 mM glucose stimulated secretion 10.4-fold. In two MIN6 cell clones stably overexpressing human LDH-A cDNA, insulin secretion was stimulated only 2.7- and 2.1-fold by high glucose. K+-stimulated insulin secretion was unaffected, and leucine stimulation enhanced, by LDH-A overexpression. LDH-A-overexpressing clones displayed unaltered activities of hexokinase, glucokinase, and malate dehydrogenase, slightly elevated plasma membrane lactate transport activity, and lowered insulin content. Low LDH activity would therefore appear important in beta-cell glucose sensing.

1-Methyl-3-isobutylxanthine↗

PubMed1998

Secretory-granule dynamics visualized in vivo with a phogrin-green fluorescent protein chimaera.

To image the behaviour in real time of single secretory granules in neuroendocrine cells we have expressed cDNA encoding a fusion construct between the dense-core secretory-granule-membrane glycoprotein, phogrin (phosphatase on the granule of insulinoma cells), and enhanced green fluorescent protein (EGFP). Expressed in INS-1 beta-cells and pheochromocytoma PC12 cells, the chimaera was localized efficiently (up to 95%) to dense-core secretory granules (diameter 200-1000 nm), identified by co-immunolocalization with anti-(pro-)insulin antibodies in INS-1 cells and dopamine beta-hydroxylase in PC12 cells. Using laser-scanning confocal microscopy and digital image analysis, we have used this chimaera to monitor the effects of secretagogues on the dynamics of secretory granules in single living cells. In unstimulated INS-1 beta-cells, granule movement was confined to oscillatory movement (dithering) with period of oscillation 5-10 s and mean displacement <1 microm. Both elevated glucose concentrations (30 mM), and depolarization of the plasma membrane with K+, provoked large (5-10 microm) saltatory excursions of granules across the cell, which were never observed in cells maintained at low glucose concentration. By contrast, long excursions of granules occurred in PC12 cells without stimulation, and occurred predominantly from the cell body towards the cell periphery and neurite extensions. Purinergic-receptor activation with ATP provoked granule movement towards the membrane of PC12 cells, resulting in the transfer of fluorescence to the plasma membrane consistent with fusion of the granule and diffusion of the chimaera in the plasma membrane. These results illustrate the potential use of phogrin-EGFP chimeras in the study of secretory-granule dynamics, the regulation of granule-cytoskeletal interactions and the trafficking of a granule-specific transmembrane protein during the cycle of exocytosis and endocytosis.

Adrenal Gland Neoplasms↗

PubMed1998

Dependence of mammalian putrescine and spermidine transport on plasma-membrane potential: identification of an amiloride binding site on the putrescine carrier.

The mechanism of mammalian polyamine transport is poorly understood. We have investigated the role of plasma-membrane potential (DeltaPsipm) in putrescine and spermidine uptake in ZR-75-1 human breast cancer cells. The rate of [3H]putrescine and [3H]spermidine uptake was inversely correlated to extracellular [K+] ([K+]o) and to DeltaPsipm, as determined by the accumulation of [3H]tetraphenylphosphonium bromide (TPP). Inward transport was unaffected by a selective decrease in mitochondrial potential (DeltaPsimit) induced by valinomycin at low [K+]o, but was reduced by approximately 60% by the rheogenic protonophore carbonylcyanide m-chlorophenylhydrazone (CCCP), which rapidly (<=15 min) collapsed both DeltaPsipm and DeltaPsimit. Plasma-membrane depolarization by high [K+]o or CCCP did not enhance putrescine efflux in cells pre-loaded with [3H]putrescine, suggesting that decreased uptake caused by these agents did not result from a higher excretion rate. On the other hand, the electroneutral K+/H+ exchanger nigericin (10 microM) co-operatively depressed -3H-TPP, [3H]putrescine and [3H]spermidine uptake in the presence of ouabain. Suppression of putrescine uptake by nigericin+ouabain was Na+-dependent, suggesting that plasma-membrane repolarization by the electrogenic Na+ pump was required upon acidification induced by nigericin, due to the activation of the Na+/H+ antiporter. The sole addition of 5-N, N-hexamethylene amiloride, a potent inhibitor of the Na+/H+ antiporter, strongly inhibited putrescine uptake in a competitive fashion -Ki 4.0+/-0.9 (S.D.) microM-, while being a weaker antagonist of spermidine uptake. The potency of a series of amiloride analogues to inhibit putrescine uptake was clearly different from that of the Na+/H+ antiporter, and resembled that noted for Na+ co-transport proteins. These data demonstrate that putrescine and spermidine influx is mainly unidirectional and strictly depends on DeltaPsipm, but not DeltaPsimit. This report also provides first evidence for a high-affinity amiloride-binding site on the putrescine carrier, which provides new insight into the biochemical properties of this transporter.

Amiloride↗