Biomedical subjects

L Shao

Publications and source records attributed to L Shao.

At least 55 records · Page 3Linked to original sources

PubMed1999

Quantitative DNA analysis of low-level hepatitis B viremia in two patients with serologically negative chronic hepatitis B.

Low-level viremia due to hepatitis B virus (HBV) was demonstrated in the sera of two patients diagnosed previously as having non-B, non-C chronic hepatitis. Both patients had a "silent" HBV infection, because they were negative for both hepatitis B surface antigen (HBsAg) and anti-hepatitis B core antibody. The TaqMan chemistry polymerase chain reaction (PCR) amplified the HBV DNA, enabling quantitation of the virus in their sera. Their serum HBV DNA concentrations were low: the amount of each HBV S or X gene amplified showed there were approximately 10(3) copies/ml and HBV DNA was detected occasionally during clinical follow-up. Positive HBsAg staining in liver tissues was demonstrated by an immunoperoxidase technique. Vertical transmission of silent HBV from one patient to her daughter was confirmed. Direct nucleotide sequencing of the amplified HBV X region revealed several mutations, suggesting reduced viral replication. One patient had a T-to-C mutation at the extreme 5'-terminus of the direct repeat 2 region and the other exhibited a coexisting X region with a 155-nucleotide deletion. These findings suggest that HBV replication is suppressed considerably in patients with silent hepatitis B.

Adult↗

PubMed1999

Rho-kinase (ROK) promotes CD44v(3,8-10)-ankyrin interaction and tumor cell migration in metastatic breast cancer cells.

Metastatic breast tumor Met-1 cells express CD44v(3,8-10), a major adhesion receptor that binds extracellular matrix components at its extracellular domain and interacts with the cytoskeletal protein, ankyrin, at its cytoplasmic domain. In this study, we have determined that CD44v(3,8-10) and RhoA GTPases are physically associated in vivo, and that CD44v(3,8-10)-bound RhoA displays GTPase activity, which can be inhibited by botulinum toxin C3-mediated ADP-ribosylation. In addition, we have identified a 160 kDa Rho-Kinase (ROK) as one of the downstream targets for CD44v(3,8-10)-bound RhoA GTPase. Specifically, RhoA (complexed with CD44v(3, 8-10)) stimulates ROK-mediated phosphorylation of certain cellular proteins including the cytoplasmic domain of CD44v(3,8-10). Most importantly, phosphorylation of CD44v(3,8-10) by ROK enhances its interaction with the cytoskeletal protein, ankyrin. We have also constructed two ROK cDNA constructs that encode for proteins consisting of 537 amino acids [designated as the constitutively active form of ROK containing the catalytic domain (CAT, also the kinase domain)], and 173 amino acids [designated as the dominant-negative form of ROK containing the Rho-binding domain (RB)]. Microinjection of the ROK's CAT domain into Met-1 cells promotes CD44-ankyrin associated membrane ruffling and projections. This membrane motility can be blocked by CD44 antibodies and cytochalasin D (a microfilament inhibitor). Furthermore, overexpression of a dominant-negative form of ROK by transfection of Met-1 cells with ROK's Rho-binding (RB) domain cDNA effectively inhibits CD44-ankyrin-mediated metastatic behavior (e.g., membrane motility and tumor cell migration). These findings support the hypothesis that ROK plays a pivotal role in CD44v(3,8-10)-ankyrin interaction and RhoA-mediated oncogenic signaling required for membrane-cytoskeleton function and metastatic tumor cell migration.

Amino Acid Sequence↗

PubMed1999

Quantitative study on expression of p16 multiple tumor suppressor gene in salivary gland neoplasm.

The expression of p16 gene in normal salivary acini, benign tumors and carcinomas were microscopically and quantitatively observed by using immunohistochemical method LSAB and CMIASWIN methods. The expression of p16 gene were found in all 3 groups. The positive unit (PU) was higher in tumor group and cancer group than that in normal group (P < 0.01). Furthermore, the PU of p16 was stronger in cytoplasm than in nucleus. Malignant tumors and acini surrounding the tumor revealed strong positives and weak positives respectively. The PU of p16 gene was higher in deep lobe of recurrent parotid neoplasm with incomplete capsule than that in shallow lobe of primary parotid neoplasm with complete capsule. The findings suggests that p16 gene plays an equally important role in the salivary gland tumors and tumors in other part of the body.

Adenoma, Pleomorphic↗

PubMed1999

Acute and chronic effects of toxic metals on viability, encystment and bioluminescence in the dinoflagellate Gonyaulax polyedra.

Toxicity bioassays based on survival were carried out with cells of the marine dinoflagellate Gonyaulax polyedra exposed to mercury (Hg2+ ), cadmium (Cd2+), lead (Pb2+) and copper (Cu2+). The toxicity scale of these metals found was Hg2+ > Cu2+ > Cd2+ > Pb2+. Cells exposed to metals promptly underwent encystment, which is an important strategy for surviving metal exposure. Following 48 h exposure to Cu2+, complete excystment occurred within 96 h after reinoculation of cells in fresh metal-free media, and with Pb2+ partial recovery occurred in that time. Bioluminescence was affected by the metals in a dose-dependent manner primarily by increasing the frequency of flashing, but the glow emission was also altered with acute Cu2+ and Pb2+ treatments. Several physiological processes in G. polyedra are under circadian control. Chronic exposures to metals caused no substantial alterations in the circadian rhythm of bioluminescence glow, indicating that the biological clock of this dinoflagellate is not sensitive to these metals at the concentrations tested.

Animals↗

PubMed1999

Differential effects of traumatic brain injury on vesicular acetylcholine transporter and M2 muscarinic receptor mRNA and protein in rat.

Experimental traumatic brain injury (TBI) produces cholinergic neurotransmission deficits that may contribute to chronic spatial memory deficits. Cholinergic neurotransmission deficits may result from presynaptic alterations in the storage and release of acetylcholine (ACh) or from changes in the receptors for ACh. The vesicular ACh transporter (VAChT) mediates accumulation of ACh into secretory vesicles, and the M2 muscarinic receptor subtype can modulate cholinergic neurotransmission via a presynaptic inhibitory feedback mechanism. We examined the effects of controlled cortical impact (CCI) injury on hippocampal VAChT and M2 muscarinic receptor subtype protein and medial septal mRNA levels at 4 weeks following injury. Rats were anesthetized and surgically prepared for CCI injury (4 m/sec, 2.5 to 2.9 mm in depth) and sham surgery. Animals were sacrificed, and coronal sections (35 microm thick) were cut through the dorsal hippocampus for VAChT and M2 immunohistochemistry. Semiquantitative measurements of VAChT and M2 protein in hippocampal homogenates from injured and sham rats were assessed with Western blot analysis. Changes in VAChT and M2 mRNA levels were evaluated by reverse transcriptase polymerase chain reaction (RT-PCR). At 4 weeks after injury, both immunohistochemical and Western blot methods demonstrated an increase in hippocampal VAChT protein. An increase in VAChT mRNA was also observed. Immunohistochemistry demonstrated a loss of M2; however, there was no significant change in M2 mRNA levels in comparison with sham controls. These changes may represent a compensatory response of cholinergic neurons to increase the efficiency of ACh neurotransmission chronically after TBI through differential transcriptional regulation.

Acetylcholine↗

PubMed1999

A cohort study of hepatitis C virus (HCV) infection in an HCV epidemic area of Japan: age and sex-related seroprevalence of anti-HCV antibody, frequency of viremia, biochemical abnormality and histological changes.

We studied the age- and sex-specific prevalence of hepatitis C virus (HCV) infection and aminotransferase abnormalities as well as histological changes in the liver associated with HCV infection. Of the eligible 3,707 inhabitants aged 6 years and older in an HCV infection epidemic area 2,382 (64.3%) were examined. The anti-HCV positivity rate was 20.7% on average and increased according to age. Age was the most potential risk indicator for anti-HCV positivity by multiple stepwise regression analysis. The HCV RNA positivity rate in females with anti-HCV was significantly lower than that in males. However, as the age of females increased, the HCV RNA positivity rate became higher. The proportion of subjects with aminotransferase abnormalities among HCV RNA-positive subjects was significantly lower in females than males. Aminotransferase abnormalities significantly increased with age in females. In subjects with abnormal aminotransferase levels, nearly half of the HCV RNA-positive females were aged 50 or older and also nearly half of the male subjects showed CAH2B or liver cirrhosis, while most of the HCV RNA-positive females younger than 50 exhibited histological findings consistent with CPH. In conclusion, age was the principal risk indicator for HCV infection in this area. Females, especially those younger than 50, both biochemically and histologically showed less severity of HCV infection than males. Gender and age might have effects on the outcome of HCV related liver disease.

Adolescent↗

PubMed1999

Molecular epidemiology of hepatitis C virus infection in an area endemic for community-acquired acute hepatitis C.

The southern district of N city (U area), Yamagata Prefecture, is highly endemic for hepatitic C virus (HCV) infection. Around 20% of the general population are positive for antibodies to HCV (anti-HCV). Community-acquired, acute non-A, non-B hepatitis was epidemic from 1967 to 1972 in this area. Our previous study revealed that these people are actually infected with HCV, but a relationship between this outbreak and the high positivity rate of anti-HCV in the U area has not been shown. We followed up 15 anti-HCV-positive individuals who developed hepatitis during the epidemic and used the serum collected to conduct molecular evolutional analysis to reveal the characteristics of the HCV epidemic in the U area. HCV genotypes in the U area were also analyzed. Phylogenetic analysis of the HCV core gene sequences showed that the subjects' HCV sequences were closely related and derived from the same cluster. All subjects were infected with HCV genotype 1b, which was frequently detected with a high positivity of over 80% of HCV-infected individuals in the U area. These results confirm that the community-acquired hepatitis C epidemic occurred around three decades ago through an unidentified route, and suggest that this episode may result in a continuing increase in the number of HCV-1b positive patients in this small area.

Acute Disease↗

PubMed1999

Relationship of TT virus infection with prevalence of hepatitis C virus infection and elevated alanine aminotransferase levels.

A novel DNA virus, TT virus (TTV), was identified in a Japanese patient with posttransfusion hepatitis. The epidemiology and etiological role of this virus have not been elucidated. We investigated the epidemiology of TTV infection in hepatitis C virus (HCV) high endemic and low endemic areas, R town and M town, respectively. The seroprevalence, potential risk factors, and laboratory features of TTV in relation to those of HCV were analyzed. TTV DNA was detected using a seminested polymerase chain reaction and the TTV genotypes were determined by a direct sequencing method. TTV DNA was detected in 16.1% of the subjects in R town and 17.5% of those in M town. The TTV DNA positivity rates of the 2 areas did not differ significantly. A history of blood transfusion was not a specific risk factor for TTV infection. The mean serum alanine aminotransferase (ALT) level of the anti-HCV-positive subjects was significantly higher than that of the TTV DNA-positive subjects, most of whom had normal ALT levels. The TTV genotype distributions of these 2 distinct areas differed. These results suggest that TTV infection is widespread with a geographical genotypic distribution independent of HCV infection and that the ALT abnormalities are not attributable to TTV but to HCV infection in the general population.

Aged↗

PubMed1999

Inhibition of cytokine-induced nitric oxide synthase expression by gene transfer of adenoviral I kappa B alpha.

BACKGROUND: Nitric oxide is overexpressed in nearly every organ during sepsis and it has profound biologic effects. Previously, we showed that maximal inducible nitric oxide synthase (iNOS) expression is up-regulated by a combination of cytokines and that this effect is mediated by the transcription factor NF-kappa B. Therefore the purpose of this study was to establish whether gene transfer of the inhibitory molecule I kappa B would result in the abrogation of cytokine-induced iNOS expression. METHODS: Cultured hepatocytes were infected with an adenoviral vector containing the I kappa B alpha gene (Ad5I kappa B) and after an 18-hour recovery period were stimulated with the cytokine mixture of tumor necrosis factor-alpha (500 U/mL) plus interleukin 1 beta (200 U/mL) plus interferon gamma (100 U/mL). RESULTS: As expected, cytokine mixture induced significant hepatocyte nitrite (NO2-) and iNOS messenger RNA production. Cells infected with the I kappa B alpha gene showed a dose-dependent decrease in NO2- and iNOS messenger RNA levels. Western blot analysis showed a marked decrease in iNOS protein levels in the presence of Ad5I kappa B alpha. Gel shift assays of nuclear extracts demonstrated that Ad5I kappa B alpha decreased the cytokine-induced DNA binding activity for NF kappa B. CONCLUSIONS: NF kappa B is an important regulator of cytokine-induced NO expression. These results identify a novel therapeutic approach where gene transfer of the inhibitory molecule I kappa B alpha can be used to down-regulate cytokine-induced iNOS expression as well as other NF kappa B-dependent genes that are up-regulated during the inflammatory response.

Adenoviridae↗

PubMed1999

[Alternation of the level of plasma calcitonin gene related peptide and endothelin-1 in liver cirrhosis].

OBJECTIVE: To investigate the level of plasma calcitonin gene related peptide (CGRP) and endothelin-1 (ET-1) to assess their role on portal hypertension formation and progression and liver function injury in liver cirrhosis and the possible relation between them. METHODS: CGRP and ET-1 were measured in plasma samples collected from 24 healthy controls and 61 liver cirrhosis patients. RESULTS: Plasma CGRP and ET-1 level were significantly higher in cirrhotic patients than those in healthy controls. Comparisons of the levels of plasma CGRP and ET-1 in group of patients with different liver function were shown as follows: Child C > Child B > Child A. An analysis among the groups showed that plasma CGRP and ET-1 were markedly higher in the groups with esophageal varices accompanied by severe or moderate ascites (LC(4)) and with simple severe or moderate ascites (LC(3)) than in the groups with esophageal varices accompanied by mild or no ascites (LC(2)). The levels were also significantly higher in group LC(2) than those in group without varices and ascites (LC(1)). No statistical difference of plasma CGRP and ET-1 levels was found between group LC(1) or Child A and normal controls. There was positive correlation between plasma CGRP and ET-1. The increased concentration of both of them correlated negatively with the declined level of plasma albumin. CONCLUSION: The increase of plasma CGRP and ET-1 is closely associated with the severity of liver cirrhosis and the formation and progression of portal hypertension. The disturbance of the balance between plasma CGRP and ET-1 may contribute to the pathologic process of liver injury.

Adult↗

PubMed1999

[Studies on immunoprotection in mice after immunization with Schistosoma japonicum 22.6 kDa recombinant protein].

AIM: To evaluate the immunoprotective effect of Schistosoma japonicum recombinant 22.6 kDa (rSj22.6) and Sj22.6/Sj26 GST fusion protein. METHODS: The Sj22.6/Sj26 GST fusion protein was prepared by affinity chromatography using glutathione Sepharose 4B. The purified rSj22.6 could be cleaved easily from the fusion protein with Thrombin. 17 and 12 mice immunized with rSj22.6 and Sj22.6/Sj26 GST separately were each challenged with 40 +/- 1 S. japonicum cercariae. RESULTS: In BALB/c mice, the rSj22.6 and Sj22.6/Sj26 GST could induce 32.1 (P < 0.005) and 34.9% (P < 0.02) worm reduction, respectively, as well as 28.4% (P < 0.02) and 45.1% (P < 0.005) total egg reduction, respectively. CONCLUSION: Bpth rSj22.6 and Sj22.6/Sj26 GST fusion protein are partially effective against S. japonicum.

Animals↗

PubMed1998

Naltrexone suppresses the rejection of cardiac tissue transplantation.

The present study demonstrates the following: 1. Transplantation of cardiac tissue induces an inflammatory response that ultimately leads to the rejection of the tissue by the host within 9 days; 2. Treatment with the opiate antagonist, naltrexone, significantly increased the survival of the transplanted cardiac tissue to 13 days, suggesting the involvement of opioid signaling molecules in tissue rejection; 3. In further experiments it was demonstrated that in mixed lymphocyte populations from different mice, the DNA synthesis inhibitor, mitomycin C, reduced the lymphocyte proliferative response as did naltrexone; 4. Mice injected with naltrexone for 10 days and given concanavalin A exhibited a suppressed spleen lymphocyte proliferative response compared to controls. Taken together, these data suggest that endogenous opioid signals not only activate immunocytes, but also stimulate DNA synthesis.

Analysis of Variance↗

PubMed1998

Targeted disruption of heat shock transcription factor 1 abolishes thermotolerance and protection against heat-inducible apoptosis.

Heat shock transcription factor 1 (HSF1) is a member of the vertebrate HSF family that regulates stress-inducible synthesis of heat shock proteins (HSPs). Although the synthesis of the constitutively expressed and inducible members of the heat shock family of stress proteins correlates with increased cellular protection, their relative contributions in acquired cellular resistance or "thermotolerance" in mammalian cells is presently unknown. We report here that constitutive expression of multiple HSPs in cultured embryonic cells was unaffected by disruption of the murine HSF1 gene. In contrast, thermotolerance was not attainable in hsf1(-/-) cells, and this response was required for protection against heat-induced apoptosis. We conclude that 1) constitutive and inducibly expressed HSPs exhibit distinct physiological functions for cellular maintenance and adaptation, respectively, and 2) other mammalian HSFs or distinct evolutionarily conserved stress response pathways do not compensate for HSF1 in the physiological response to heat shock.

Alleles↗

PubMed1998

Effect of rodent hepatocarcinogenic peroxisome proliferators on fatty acyl-CoA oxidase, DNA synthesis, and apoptosis in cultured human and rat hepatocytes.

The effects of the rodent hepatocarcinogens clofibric acid and diprofibrate on the activity of the peroxisomal fatty acyl-CoA oxidase, DNA synthesis, and apoptosis were compared in cultured rat and human hepatocytes. Rat hepatocytes expressed a 10-fold greater level of the peroxisomal fatty acyl-CoA oxidase compared to human hepatocytes. At the highest concentration (1.0 mM), both drugs induced a two- to threefold increase in this enzyme activity in both rat and human hepatocytes. Ciprofibrate (0.1 and 0.2 mM) caused a twofold increase in DNA synthesis in rat hepatocytes, whereas clofibric acid had no effect on DNA synthesis in these cells. In contrast, increasing concentrations of both clofibric acid and ciprofibrate produced inhibition of DNA synthesis in human hepatocytes. By using the terminal transferase dUTP-biotin nick end labeling technique, it was observed that 0.1 and 0.2 mM clofibric acid and ciprofibrate suppressed transforming growth factor-beta (TGF beta)-induced apoptosis by 50% in rat hepatocytes, but they had no effect on TGF beta-induced apoptosis in human hepatocytes. Although clofibric acid and ciprofibrate diminished TGF beta-induced apoptosis, they had no effect on the basal apoptotic levels in the rat hepatocyte cultures. However, both drugs significantly increased the percent of apoptotic cells in the human hepatocyte cultures. It is concluded that primary rat and human hepatocyte cultures respond differently to peroxisome proliferators. The differences in effects on DNA synthesis and apoptosis support the hypothesis that human liver cells are refractory to peroxisome proliferator-induced hepatocarcinogenesis.

Acyl-CoA Oxidase↗

PubMed1998

[Association between levels of plasma lipid profile with apolipoprotein B gene polymorphism in 93 children].

OBJECTIVE: To study the relationship between levels of plasma lipid profile and variation of apolipoprotein (Apo) B gene. METHODS: The relationship between frequency of polymorphism genotype of Apo B gene Xba I locus and levels of plasma lipid profile was studied in 93 children aged eight to eleven years. RESULTS: The frequency of dominant X- allele (common allele) in Xba I locus was 0.967 in the children and that of uncommon X+ allele 0.033. Average levels of plasma total cholesterol (TC) and low density lipoprotein cholesterol (LDL-ch) in children with X- X+ genotype (4.59 and 2.98 mmol/L, respectively) were significantly higher than those with X-X- genotype (3.84 and 2.32 mmol/L, respectively). Levels of TC and/or LDL-ch in 4 of 6, cases of X-X+ genotype exceeded their the 90th percentile, indicating association between X+ allele and high plasma cholesterol level. CONCLUSION: To certain extent, there is association between polymorphism of Xba I locus of Apo B gene and levels of plasma lipid profile in children, which may be a genetic marker for abnormal level of plasma lipid profile during childhood.

Apolipoproteins B↗

PubMed1998

[Reoperation for recurrent carcinoma of the esophagus and cardia].

OBJECTIVE: To review the experience of reoperation for recurrent carcinoma of the esophagus and cardia. METHOD: Between 1979 and 1996, 44 patients with recurrent esophageal and cardiac cancer after the first operation underwent reoperation. Among them, 21 had esophageal cancer and 23 cardiac cancer. 36 patients were male and 8 female, with age ranged from 42 to 68 years. RESULT: The resectability rate was 77.2% (34/44) and the hospital mortality rate was 5.8%. Postoperative complications occurred in 7 patients with a morbidity of 20.5%. Pathologically, previous anastomotic relapse was seen in 26 patients, recurrent lesion of residual esophagus in 7, and recurrent cancerous residue at the esophageal bed in 1. 15 patients (44%) showed lymph node metastasis. Follow-up showed that 4 patients survived for 5 years, 4 for 3 years, and 3 for 2 years. 15 patients died within one year after reoperation. CONCLUSION: The recurrence of esophageal and cardiac cancer after first operation is not a contraindication to reoperation, but careful preoperative assessment and patients' selection should become an integral part of the evaluation of these patients.

Adult↗

PubMed1998

Epidemiological study and genetic analysis of GB virus C infection in general population from an area endemic for hepatitis C.

The aim of this work was to study the prevalence, potential risk factors, clinical and laboratory features of GB virus C (GBV-C) infection in general population from an area endemic for hepatitis C. A reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of GBV-C RNA was used to examine the prevalence of GBV-C RNA in both hepatitis C virus (HCV) endemic (R town) and nonendemic areas (M town) in Yamagata prefecture, Japan. In R town, GBV-C RNA was detected in 23 (2.9%) out of the 800 residents, whereas anti-HCV and HCV-RNA were found in 226 (28.3%) and 163 (20.4%), respectively. The prevalence of GBV-C RNA in R town (2.9%) was higher than that in M town (1.0%), although the difference was not statistically significant. The individuals with anti-HCV had significantly higher frequency of active GBV-C-infection than those without anti-HCV in both towns. No evidence indicating that GBV-C infection affected the severity of hepatitis C was obtained. The multivariate analysis revealed that the young anti-HCV positive individuals with a history of blood transfusion had higher incidence of active GBV-C infection. The phylogenetic analysis showed that the GBV-C isolates from both R and M towns were divided into two separate branch groups designated HG and Asia GB groups.

Adult↗

PubMed1997

Regulation of the rat interstitial collagenase promoter by IL-1 beta, c-Jun, and Ras-dependent signaling in growth plate chondrocytes.

In an attempt to better define molecular influences on rat interstitial collagenase gene expression in cartilage, the promoter function was characterized using transient transfection assay, electrophoresis mobility shift assay, and genetic analysis in isolated growth plate chondrocytes. Data from 5'-flanking deletion and selected mutations suggest that multiple cis elements in both the proximal and distal regions of the promoter were important in the regulation of promoter activity. A proximal tumor response element (TRE) was shown to be necessary for basal and interleukin (IL)-1 beta-inducible reporter gene activity. Cells stimulated by IL-1 beta (1 ng/ml; 18 h) had elevated TRE binding activity, and one of the factors involved was identified as the nuclear protein, c-Jun. Indeed, c-Jun directed antisense oligonucleotides reduced rat interstitial collagenase mRNA. A sense oligonucleotide was ineffective. Regulation of promoter activity was susceptible to Ras-dependent signaling as expression of dominant negative mutant of Ras kinase (pZIP-RasN17) reduced reporter gene activity. In a comparison of proximal promoter reporter plasmid activity between proliferative and hypertrophic cells, inhibition of Ras-dependent signaling was less effective in the later cell type. This study suggests that the activation of nuclear binding proteins that bind TRE may be a common event with IL-1 beta regulation. Moreover, these data suggest that the regulation of rat interstitial collagenase gene expression is a combinatorial process and multiple cis-acting regulatory sites may interact to exert different effects dependent on the stage of chondrocyte differentiation.

Animals↗