Biomedical subjects

B Hu

Publications and source records attributed to B Hu.

At least 163 records · Page 9Linked to original sources

PubMed1999

[Clinical application of expandable metal stent for palliation of malignant biliary obstruction].

OBJECTIVE: To investigated the long-term result of expandable metallic biliary stent implantation and evaluated preliminarily the factors that might impact the therapeutic effectiveness. METHODS: 134 patients with malignant choledochal stenosis were treated with metallic endo-prosthesis (128 transpapillary endoscopically and 6 transhepatic percutaneously). The follow-up results were compared with those of 97 patients with conventional plastic stents during the same period. RESULTS: The success rate was 95.7%, and the procedure related complications were found in 6.4% of patients. The jaundice was eliminated completely in 85.6% patients. During long-term follow-up, the metal stents were shown patent for a mean duration of 300 days, which was significantly longer than 80 days of polyethylene endoprostheses (P < 0.01). The mean survival was 210 days. From classified data assessment, the stent patency in primary bile duct neoplasm group was almost similar to that in metastatic group, but the median survival of the former was slightly longer than that of the latter. There were flow differences in patancy and survival rates between the hilar obstruction group and the middle and low obstruction group. CONCLUSIONS: The median patancy of expandable metal stents was significantly longer than that of conventional plastic prostheses. To get the highest benefit, however, the indication should be strictly selected.

Adult↗

PubMed1999

[Smoking, related cancers, and other diseases in shanghai: a 10-year prospective study].

OBJECTIVE: To explore the relationship between smoking and related diseases among residents of Shanghai. METHODS: A cross-sectional study on current smoking status among 213,800 residents aged 20 yr and over in Shanghai urban, suburb and rural areas was carried out during the early 1980s. The residents in the urban area were followed up for 12 years (1983 - 1994) and those in suburb and rural areas for 11 years (1984 - 1994). A Poisson regression model was used to estimate relative risks RRs of certain diseases for smoking adjusted for age with their 95% confidence intervals by sex and area among persons aged 40 yr and over at the beginning of the study. RESULTS: In the urban area, the RRs of death for smoking were 1.48 and 1.62 in males and females, respectively and for cancer death were 2.20 and 2.00. Statistically significant elevated RRs were seen for cancers of the lung and liver in both males and females and for cancers of the oesophagus, stomach, pancreas and bladder only in males. Significantly higher RRs were also observed for cerebrovascular disease, chronic bronchitis and emphysema, and pulmonary heart disease. RRs lower than in the urban area were found in the suburb and rural areas. The population attributable risks (%, PAR) for death due to smoking for males were estimated by area. PARs for death were 20.9, 18.9 and 16.3 in urban, suburb and rural areas, respectively. For all cancers, PARs were 40.0, 34.5 and 34.2 and for lung cancer were 71.7, 59.2 and 64.7. CONCLUSION: Smoking was associated with the mortality of some common cancers, chronic bronchitis, and emphysema, pulmonary heart, and cerebrovascular diseases.

China↗

PubMed1999

[Skeletal effect of xianzhen gubao on preventing prednisone-induced osteoporosis in male rats].

OBJECTIVE: To study the effect of Chinese medicine Xianzhengubao (XZGB) capsules of compound prescription on corticosteroid-induced osteoporosis in rats. METHOD: 3-month-old SD male rats were randomly divided into basal control and aging control, prednisone (4.5 mg.kg-1, ig, twice a week) and XZGB capsules were used in three different doses (0.2, 0.4, 0.8 g.kg-1.d-1 ig)6 times a week. All the rats were killed. On the 90th day afteradministration. The proximal tibiae were processed in undecalcified sections at a thickness of 4-10 microns for histomorphometric analysis. RESULT: Compared with the aging controls corticosteroid reduced markedly the trabecular bone mass due to increase of bone resorption and decrease of bone formation (%Tb. Ar 52.9%). Treatment with XZGB capsules in high doses increased significantly the trabecular area as compared with the hormone control(% Tb. Ar + 91.2%). The protective mechanism of XZGB capsules mainly consists in suppressing bone resorption and mildly increasing bone formation in rats. CONCLUSION: Xianzhen gubao capsules have an effect on preventing bone loss in rats induced by corticosteroid, and higher doses produce greater effect.

Animals↗

PubMed1999

[A dynamic study of influences of TMJOA on TMJ disc].

OBJECTIVE: To learn the changes of TMJ disc positions under the influences of TMJ Osteoarthrosis(TMJOA). METHODS: The TMJOA experimental animal model was established by 12 goats. The TMJ disc positions were observed and recorded at different intervals, (1 month, 2 months, 3 months, 4 months and 6 months) then the pathological changes of TMJ specimens were also studied. RESULTS: Significant anteromedial shift of TMJ disc position was observed in some certain TMJOA phases and became more obviously along with the disease progress. CONCLUSION: The shift of TMJ disc may be the secondary change of TMJOA.

Animals↗

PubMed1999

[Localization with BrUTP labeling technique of RNA polymerase II transcription in meristematic cells of Allium cepa].

The technique of pulse-labeling of cells with 5-bromouridine-5'-triphosphate (BrUTP) and immunological detection of the incorporated BrUTP is a newly-developed experimental approach to localize nascent RNA polymerase II transcripts in the nucleus. This technique has been widely used since it was first reported in 1993, but most of the studies were carried out with fluorescence microscopy and animal cells, we are still limited in the knowledge about ultrastructural localization of RP II transcripts in the nucleus of eukaryotes, especially in that of plant cells. Attempts have been made in this paper to localize nascent RP II transcripts in the nucleus of meristematic cells of Allium cepa with the technique of pulse-labeling of BrUTP and immunoelectron microscopy. After labeling with BrUTP and detection with anti-BrdU antibody, a large number of gold particles representing RP II transcripts were observed in the periphery of chromatin domains, the gold particles in the periphery accounted for 92.70% of the total gold particles in the extranucleolar regions, and the gold density of the periphery was 75.42/micron 2, much higher than that of the center of the chromatin domains and the interchromatin domains which were only 5.89/micron 2 and 2.00/micron 2 respectively, indicating that RP II transcripts were being actively synthesized in the periphery of the chromatin domains. When the specimens were treated with alpha-amanitin which can specifically inhibits the activity of RP II, gold particles in the extranucleolar regions of the specimens were decreased dramatically and the gold density of the regions dropped strikingly from 44.60/micron 2 to 2.67/micron 2, confirming that the gold particles in the regions represent RP II transcripts. The distribution of nascent RP II transcripts in the nucleus of the intact plant cells is discussed.

Allium↗

PubMed1999

[Study of dental model testing tool based on robot theory].

A new three dimensional testing and analysing system of dental model is discussed It is designed based on the motion theory of robots. The system is capable of not only measuring the three dimensional sizes of dental models, but also saving and outputing the tested data. The construction of the system is briefly introduced here.

Equipment Design↗

PubMed1999

[The effects of salicylate on noise-induced hearing loss in the guinea pig].

OBJECTIVE: To investigate the effects of salicylate on noise-induced hearing loss (NIHL) in guinea pigs. METHODS: The animals were allocated into four groups (salicylate + noise, saline + noise, noise only and salicylate only) and were exposed to a 4 kHz octave band noise at 105 dB SPL for 2 hours for 5 consecutive days. Dynamic changes of ABR thresholds evoked by clicks were monitored. After physiological examination, the cochleae were processed for the morphological examination by light microscopy. RESULTS: Mean thresholds of ABRs in the experimental group obtained on 5th day of the noise exposure was positively lower than the control groups (P < 0.05). The similar trends of ABR changes were found during other exposure days and after exposure, but the differences were not statistically significant. In the experimental group, there were 37.00 +/- 8.89 hair cell loses as assessed by nucleus staining, and 3.20 +/- 1.07 hair cells with nuclear deformation. The noise group had 74.11 +/- 10.28 hair cell loses and 10.43 +/- 9.71 hair cells with nuclear deformation, whereas the saline group had 63.60 +/- 7.97 hair cell loses and 20.80 +/- 15.48 hair cells with nuclear deformation. The difference between two groups was significant (P < 0.05). CONCLUSION: The results suggest that administration of salicylate facilitates the recovery of cochlear hearing and reduces damage to hair cells after noise exposure.

Animals↗

PubMed1998

Cloning and expression of a novel dominant-negative-acting estrogen response element-binding protein in the heterogeneous nuclear ribonucleoprotein family.

Most genera of New World primates exhibit a compensated form of resistance to steroid hormones produced by the adrenal gland, gonads, and kidney. Estrogen resistance in New World primate cells is associated with the relative overexpression of a nonreceptor-related estrogen response element-binding protein (ERE-BP) that competes with estrogen receptor for ERE binding. Using the concatamerized ERE half-site (AGGTCAcag) in DNA affinity chromatography, we purified to homogeneity a 40-42-kDa ERE-BP. The affinity-purified ERE-BP bound specifically to either single- or double-stranded DNA bearing the consensus ERE half-site motif AGGTCA. Four distinct internal tryptic peptides from this protein were generated and shown to exhibit sequence similarity to proteins in the heterogeneous nuclear ribonucleoprotein family. These tryptic peptide fragments were used to generate a series of degenerate oligonucleotides that were successfully employed in isolating a full-length ERE-BP cDNA by polymerase chain reaction. Although a member of a family of proteins generally recognized for their ability to bind single strand RNA, the estrogen resistance-associated protein ERE-BP can effectively bind double strand DNA and competitively squelch estrogen receptor-directed transactivation.

Amino Acid Sequence↗

PubMed1998

Synthesis of rotavirus-like particles in insect cells: comparative and quantitative analysis.

When the three major structural proteins, VP2, VP6, and VP7, of rotavirus are co-expressed in insect cells infected with recombinant baculoviruses, they self-assemble into triple-layered virus-like particles (VLPs) that are similar in morphology to native rotavirus. In order to establish the most favorable conditions for the synthesis of rotavirus VLPs, we have compared the kinetics of 2/6/7-VLP synthesis in two different insect cell lines: High Five cells propagated in Excell 405 medium and Spodoptera frugiperda 9 cells in Excell 400 medium. The majority of VLPs produced in both cell lines were released into the culture medium, and these released VLPs were predominantly triple-layered and were found to be stable for the period of six or seven days examined. The optimal synthesis of VLPs depended upon the cell line and the culture medium used as well as the time of harvesting infected cell cultures. The highest yield of VLPs was obtained from High Five cultures in the late phase of infection when the yield was at least 5-fold higher than that from S. frugiperda 9 cultures on a per cell basis. Our results demonstrate the usefulness of High Five cells for the production of VLPs as potential rotavirus subunit vaccines.

Animals↗

PubMed1998

Diversity of HIV-1 Vpr interactions involves usage of the WXXF motif of host cell proteins.

Targeting protein or RNA moieties to specific cellular compartments may enhance their desired functions and specificities. Human immunodeficiency virus type I (HIV-1) encodes proteins in addition to Gag, Pol, and Env that are packaged into virus particles. One such retroviral-incorporated protein is Vpr, which is present in all primate lentiviruses. Vpr has been implicated in different roles within the HIV-1 life cycle. In testing a new hypothesis in which viral proteins are utilized as docking sites to incorporate protein moieties into virions, we used the peptide phage display approach to search for Vpr-specific binding peptides. In the present studies, we demonstrate that most of the peptides that bind to Vpr have a common motif, WXXF. More importantly, we demonstrate that the WXXF motif of uracil DNA glycosylase is implicated in the interaction of uracil DNA glycosylase with Vpr intracellularly. Finally, a dimer of the WXXF motif was fused to the chloramphenicol acetyl transferase (CAT) gene, and it was demonstrated that the WXXF dimer-CAT fusion protein construct produces CAT activity within virions in the presence of Vpr as a docking protein. This study provides a novel potential strategy in the targeting of anti-viral agents to interfere with HIV-1 replication.

Amino Acid Sequence↗

PubMed1998

Mallory body formation by ethanol feeding in drug-primed mice.

Drug-primed mice, created by a 5-month feeding of diethyl-1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate (DDC), followed by a 1-month withdrawal, were refed ethanol or isocaloric dextrose (control) diets intragastrically for 7 days. The formation of Mallory bodies (MBs) was monitored by immunofluorescence and immunoperoxidase microscopy using antibodies to cytokeratin and ubiquitin, and also by electron microscopy. The changes in cytokeratin 55 (CK55), ubiquitin conjugate, nuclear factor kappaB (NFkappaB) p65, NFkappaB p50, inhibitor kappaB alpha, c-myc, tumor necrosis factor alpha, and cytochrome P450 2E1 (CYP2E1) contents were determined by Western blotting using appropriate antibodies. The messenger RNA (mRNA) for CYP2E1, cytokeratin, ubiquitin, hepatocyte growth factor activator, and tissue transglutaminase was quantitated. MBs were present at 5 to 7 days' postfeeding with ethanol, but not with dextrose. They developed in clusters of "empty hepatocytes," where the cytokeratin antibody failed to recognize the typical filament structures seen in normal hepatocytes. MBs were larger and more numerous in the subcapsular region. Northern blots showed that CK55 mRNA was decreased by the ethanol treatment, but protein levels were increased, suggesting a decreased turnover of the cytokeratin. Likewise, the increase in CYP2E1 protein in the face of a lack of an increase in mRNA for CYP2E1 could be explained by a decreased turnover of this cytochrome. This is the first report of MB formation induced by ethanol ingestion in an experimental model.

Animals↗

PubMed1998

Mechanisms of mallory body formation induced by okadaic acid in drug-primed mice.

Drug-primed mice form Mallory bodies in their liver after various types of liver injury such as heat shock, drug refeeding, or ethanol ingestion. However, the mechanisms involved that lead to Mallory body formation after these different treatments are unknown. There may be a common pathway of Mallory body formation that is initiated by these different types of injuries. Recently it was shown that the phosphatase 1/2A inhibitor okadaic acid induced Mallory body formation, suggesting that the mechanism of formation involves hyperphosphorylation or oxidative stress-induced NFkappaB activation. To test this hypothesis we exposed drug-primed mice to okadaic acid and measured phosphorylation of Mallory body proteins immunohistochemically and by immunoblot chemiluminescence using an antibody specific for phosphothreonine. NFkappaB activation was measured by a gel shift retardation assay of nuclear lysates. Beginning 15 min after okadaic acid injection, complex changes were progressively seen in the liver cells focally including aggregation of cytokeratins 8 and 18 in hepatocytes which otherwise failed to stain normally with cytokeratin antibody. The aggregates stained positive with ubiquitin and phosphothreonine antibodies. Immunoblots showed a progressive increase in positive staining of the Mallory body band with the antibody to phosphothreonine. NFkappaB activation was progressive up to 2 h after okadaic acid treatment but was downregulated 7 days later. In summary we show for the first time the effect of okadaic acid on the liver cytokeratins in vivo. We conclude that hyperphosphorylation and NFkappaB activation may play a role in the early phases of Mallory body formation.

Animals↗

PubMed1998

Expression of functional domain of chicken gizzard calponin.

A full-length cDNA of the function domain of wild-type chicken gizzard calponin was cloned into expression vector pAED4 and the recombinant function domain of wild-type calponin was expressed in an Escherichia coli expression system. The actin domain of calponin (CaP-B) can bind with actin and it is a requisite for its inhibition of ATPase and vasoconstriction of smooth muscle. In this study, the cDNA of CaP-B was inserted into vector pAED4 by direction-cloning method. The cDNA of CaP-B was obtained with PCR cloning technique. The recombinant DNA pAED4-Cap-B was transformed into E. coli BL21 (DE3) and identified with the restriction analysis. The bacterial clones containing transformants were induced to be highly expressed in E. coli BL21 (DE3). The target protein was detected and identified by Western Blot analysis. The content of target protein was as high as 10% of the whole protein after overnight (16 h) culture. The results confirmed that Cap-B was relatively highly expressed in E. coli.

Animals↗

PubMed1998

Unidirectional axonal transport in in vitro adult rat brain explants.

The present study examined the properties of anterograde and retrograde transport in central axonal pathways maintained in vitro. The commonly-used tracers biocytin, dextran rhodamine B, FluoroGold, True Blue or rhodamine latex microspheres were injected into the medial geniculate body or the inferior colliculus of the adult rat brain explant. Injection of biocytin into the inferior colliculus consistently resulted in extensive anterograde labelling of axonal trunks and terminals in the ipsilateral medial geniculate body and in the contralateral inferior colliculus. Labelled axons were obtained 2-3 h after the injection at a site 3-4 mm away from the injection site and could be found up to 1.5 mm below the explant surface. Despite massive anterograde labelling with biocytin, all the tracers applied in the gray or white matter failed to show retrograde transport. These results suggest that axonal transport can occur in an anterograde-selective fashion in adult brain explants in vitro.

Animals↗

PubMed1998

Changes in cochlear antioxidant enzyme activity after sound conditioning and noise exposure in the chinchilla.

Exposure to low level noise prior to a high level exposure reduces noise-induced hearing loss in mammals. This phenomenon is known as sound conditioning or 'toughening'. Reactive oxygen intermediates have been implicated in noise-induced cochlear damage. To evaluate if in situ antioxidant processes may play a role in the toughening phenomenon initiated by low level noise exposure we analyzed glutathione reductase, gamma-glutamyl cysteine synthetase, and catalase in stria vascularis and organ of Corti fractions from cochleae of chinchillas exposed to a sound conditioning paradigm. Chinchillas were either (A) kept in quiet cages (control), (B) exposed to conditioning noise of a 0.5 kHz octave band (90 dB for 6 h/day for 10 days), (C) exposed to high level noise (105 dB for 4 h) or (D) exposed to conditioning noise (B) followed by exposure to the higher level noise (C). Each of the noise exposure conditions (B, C, D) induced changes in the levels of these three antioxidant enzymes. The enzyme-specific activity data for the four subject groups support the following two hypotheses. (1) Changes in glutathione reductase, gamma-glutamyl cysteine synthetase, and catalase play a role in attenuating hearing loss associated with sound conditioning followed by high level noise. (2) Hair cells in the organ of Corti are protected from noise-induced damage by increasing stria vascularis levels of catalase, a hydrogen peroxide scavenging enzyme, and of enzymes involved in maintaining glutathione in the reduced state. The model formulated by these hypotheses suggests that agents that protect or augment the glutathione system in the cochlea may be protective against noise-induced hearing loss.

Acoustic Stimulation↗

PubMed1998

Regulation in the rpoS regulon of Escherichia coli.

In Escherichia coli, the transcription factor sigma s, encoded by rpoS, controls the expression of a large number of genes involved in cellular responses to a diverse number of stresses, including starvation, osmotic stress, acid shock, cold shock, heat shock, oxidative DNA damage, and transition to stationary phase. A list of over 50 genes under the control of rpoS has been compiled. The transcription factor sigma s acts predominantly as a positive effector, but it does have a negative effect on some genes. The synthesis and accumulation of sigma s are controlled by mechanisms affecting transcription, translation, proteolysis, and the formation of the holoenzyme complex. Transcriptional control of rpoS involves guanosine 3',5'-bispyrophosphate (ppGpp) and polyphosphate as positive regulators and the cAMP receptor protein-cAMP complex (CRP-cAMP) as a negative regulator. Translation of rpoS mRNA is controlled by a cascade of interacting factors, including Hfq, H-NS, dsrA RNA, LeuO, and oxyS RNA that seem to modulate the stability of a region of secondary structure in the ribosome-binding region of the gene's mRNA. The transcription factor sigma s is sensitive to proteolysis by ClpPX in a reaction that is promoted by RssB and inhibited by the chaperone DnaK. Despite the demonstrated involvement of so many factors, arguments have been presented suggesting that sensitivity to proteolysis may be the single most important modulator of sigma s levels. The activity of sigma s may also be modulated by trehalose and glutamate, which activate holoenzyme formation and promote holoenzyme binding to certain promoters.

Bacterial Proteins↗

PubMed1998

Skeletal effects of constant and terminated use of sodium risedronate in ovariectomized rats.

AIM: To study the skeletal effects of constant and terminated use of sodium risedronate (Ris) treatment in the ovariectomized (Ova) rats. METHODS: Ris 5 micrograms.kg-1, s.c., twice a wk. The proximal tibial metaphysis (PTM) were processed undecalcified for quantitive bone histomorphometry. RESULTS: (1) Placebo-treated (normal saline) Ova rats were characterized by decreased trabecular area (TA) on d 60, d 81, and d 150 compared with aging controls, and bone resorption was over formation with high bone turnover. (2) Ova rats were treated with Ris for 60, 81, and 150 d (Ris-on) increased. (TA 217%, 108%, and 101%) respectively, vs Ova rats and depressed bone turnover indices to aging control level, but bone mass did not maintain at high level in 150-d group as in the early stage. (3) Ova rats were pretreated with Ris for 60 d and then terminated (Ris-on/off), followed by sequential sacrifice of rats on 21 and 90 d. Withdrawal on 21 d showed the same results as the match-age Ris-on group. Withdrawal on 90 d still maintained cancellous bone mass at a high level vs 150 d Ris-on groups (+26%) and aging control group (+27%). CONCLUSION: Regimen of Ris 60 d on then 90 d off prevented the development of osteoporosis in Ova rats.

Animals↗

PubMed1998

[Infection of cryptosporidium in child patients with diarhea in Changsha].

Fecal specimens were collected from 102 outpatients with diarrhea in Children's Hospital from March to October, 1997. The fecal smears were examined for cryptosporozoites with the rapid modified acid-fast two-step methods. The positive rate was 4.90%(5/102). There was no significant difference between female and male (P > 0.05). The positive rates of 1-month-, 5-year-, and 10-year-old groups were 4.05% (3/74), 7.14%(1/14), and 7.14(1/14), respectively. We conclude that there is crytosporidium infection in child patients with diarrhea in different sex and age groups.

Adolescent↗