Sister chromatid exchanges and high-frequency cells in men environmentally and occupationally exposed to ambient air pollutants: an intergroup comparison with respect to seasonal changes and smoking habit

Sister chromatid exchanges (SCE) and high-frequency cells (HFC) were measured in peripheral blood lymphocytes from men environmentally and occupationally exposed to a mixture of ambient air pollutants. The environmentally exposed individuals were inhabitants of the industrial region of Upper Silesia; those occupationally exposed were Silesian cokery or steel plant workers, while the control group consisted of rural region residents. A total of 147 males were enrolled in the study. Blood samples were collected in winter (February) and summer (September) seasons. Three major areas were investigated during the study: exposure-based dose dependency, seasonal changes, and influence of smoking habits on the SCE frequencies. The latter is frequently reported as a confounding factor in SCE analyses. In both winter and summer samples, statistically significant increases of SCE were observed in the environmentally and occupationally exposed groups compared to the controls (p < 0.001). The difference between both exposed groups was also significant (p < 0.001). An intergroup comparison was based on ANOVA after adjustment for smoking status. In all three groups of interest, a seasonal variation was found with higher levels in winter. However, in a part of the study in which each donor served as his own control, statistical differences were only found within the exposed groups. Control region inhabitants did not have significantly higher frequencies of SCE in winter, compared to summer samples. The impact of two major confounders, age of the donor and smoking habit, was investigated by multiple regression analysis. Smoking was a major factor influencing the level of SCE. Nevertheless, the effect was seen in winter samples only, which suggests an additive response and adds new information to this known effect.

Reference spirometric values in healthy Chinese neversmokers in two townships of Taiwan

The present community-based study was performed to provide predictive equations and lower boundaries of normal values for forced expiratory volume in one second (FEVI), forced vital capacity (FVC), and their percent ratio (FEV1%) in non-smoking, healthy adult men and women residing in communities, using ATS-recommended techniques and equipment. Use was made of data collected cross-sectionally from Nov. 1990 to Dec. 1993 in an ongoing longitudinal study on evolution of cardiovascular disease risk factors in Chinese. The spirometric values in our population reached their peak at around age 20. After age 20, a downward age trend was observed for FVC, FEV1, and FEV1%. Linear and negative relations were found in adults for each of the three spirometric values with age. Linear and positive relations were found between height and FVC or FEV1, but not between height and FEV1%. The age trends of FVC and FEV1 in Chinese adults were similar to those in Caucasians. Mean FVC and FEV1 levels of Chinese in Taiwan were systematically lower than those of Caucasians for a given height and a given age. Age and height specific percentile values of FVC and FEV1 and the age-specific percentile value of FEV1% are provided for adult men and women in this community study.

hSK4, a member of a novel subfamily of calcium-activated potassium channels

The gene for hSK4, a novel human small conductance calcium-activated potassium channel, or SK channel, has been identified and expressed in Chinese hamster ovary cells. In physiological saline hSK4 generates a conductance of approximately 12 pS, a value in close agreement with that of other cloned SK channels. Like other members of this family, the polypeptide encoded by hSK4 contains a previously unnoted leucine zipper-like domain in its C terminus of unknown function. hSK4 appears unique, however, in its very high affinity for Ca2+ (EC50 of 95 nM) and its predominant expression in nonexcitable tissues of adult animals. Together with the relatively low homology of hSK4 to other SK channel polypeptides (approximately 40% identical), these data suggest that hSK4 belongs to a novel subfamily of SK channels.

3-Phosphohistidine cannot replace phosphotyrosine in high-affinity binding to phosphotyrosine binding or Src homology 2 domains

Posttranslational phosphorylation of proteins is an important event in many cellular processes. Phosphorylated tyrosine residues can serve as association sites for other proteins in signal transduction cascades of tyrosine kinase receptors. Formation of phosphohistidine residues in proteins has been found in eukaryotic and prokaryotic organisms. Furthermore, it has been suggested that phosphohistidine might substitute for phosphotyrosine in conferring high-affinity binding to proteins involved in signal transduction. We have analyzed the ability of 3-phosphohistidine to associate with the known phosphotyrosine-specific phosphotyrosine binding and src homology 2 protein domains. From our binding studies using synthetic peptides, we conclude that 3-phosphohistidine cannot replace phosphotyrosine in conferring high-affinity binding to the phosphotyrosine binding domain of shc or the src homology 2 domain of phospholipase C-gamma1.

p53 mutations, chronic hepatitis B virus infection, and aflatoxin exposure in hepatocellular carcinoma in Taiwan

Recent studies have implicated aflatoxin B1 (AFB1) exposure as an etiological agent in hepatocellular carcinoma (HCC) and suggested an interaction with chronic hepatitis B virus (HBV) infection. Worldwide AFB1 exposure correlates with a specific mutation at codon 249 in the p53 tumor suppressor gene in liver tumors. This study investigated the roles of HBV and AFB1 in the HCC carcinogenic pathway involving p53 mutations. In cases and controls, chronic HBV infection was assessed by serum hepatitis B surface antigen (HBsAg) and AFB1 exposure by immunohistochemical detection of AFB1-DNA adduct in liver tissue. p53 protein mutations in tumor tissues of HCC cases were identified by immunohistochemistry and DNA mutations by single-stranded conformational polymorphism and sequencing analysis. Both chronic HBsAg carrier status and liver AFB1-DNA adducts were significantly higher in cases than in controls with odds ratios (OR) of 8.4 and 3.9, respectively (P < 0.01). Moreover, HCC risk was greatest in individuals with both AFB1-DNA adducts and HBsAg, suggesting a viral-chemical interaction. Mutant p53 protein, mutations in the p53 gene, and specific codon 249 mutations were detected in 37, 29, and 13%, respectively, of the HCC cases. Most of the DNA mutations were transversions, and the only major clustering site for mutations was codon 249. AFB1-DNA adducts were associated with p53 protein (OR = 2.9, P = 0.054) and DNA mutations (OR = 2.9, P = 0.082) but with borderline significance. All of the codon 249 mutations (n = 12) occurred in HBsAg-seropositive carriers, resulting in an OR of 10.0 (P < 0.05), suggesting that HBV may be involved in the selection of these mutations. The ORs between HBsAg and p53 DNA and protein mutations were 2.6 (P = 0.077) and 1.8 (P > 0.05), respectively. Both p53 DNA and protein mutations were related to tumor stage, suggesting that they are late events. These studies provided further support for the role of aflatoxin exposure in HCC in Taiwan and insight into viral-chemical interactions and molecular pathogenesis.

Congenital rickets--a patient report

We present a premature newborn with congenital rickets, born to a mother with untreated chronic renal insufficiency. X-ray films showed blurred metaphyseal ends and decreased bone density in the femurs and ribs. With treatment including calcium, phosphate, and vitamin D, her rickets healed and she grew normally.

Clinical experience with early enteral feeding in very-low-birth-weight infants

The primary objective of this study was to evaluate the safety and benefit of early enteral feeding in very-low-birth-weight (VLBW) infants without parenteral nutrition. Weight gain, feeding intolerance, nosocomial infection rate and a postnatal growth curve were recorded for 61 VLBW premature infants who were admitted to the Neonatal Intensive Care Unit of Mackay Memorial Hospital from September 1, 1995 to February 28, 1997. Nine infants were unable to complete the study and three were excluded because of severe bronchopulmonary dysplasia; therefore only 49 infants could be evaluated. They were divided into two groups based on birth weight: 1001 gm to 1250 gm (Group A, mean birth weight 1153 +/- 64 gm, mean gestational age 29.0 +/- 2.2 weeks), and less than or equal to 1000 gm (Group B, mean birth weight 911 +/- 82 gm, mean gestational age 27.1 +/- 1.5 weeks). They received breast milk or premature formula by intermittent nasogastric or continuous nasogastric feeding. Growth was followed over the first 30 postnatal days. Group A reached 100 kcal/kg/day of enteral feeding at a mean age of 17 days as compared with a mean age of 20 days for group B. Infants regained their birth weight at 20 and 25 days in Groups A and B, respectively. By the 30th postnatal day, weight gain exceeded birth weight by 218.2 +/- 143.1 gm and 95.3 +/- 81.5 gm in groups A and B respectively. No definite episodes of necrotizing enterocolitis (NEC) developed. Two cases of Escherichia coli sepsis and one of Klebsiella sepsis occurred. The conclusion was that early enteral feeding in very-low-birth-weight infants does not increase the risk of NEC. It was also demonstrated that enteral feeding alone can produce biphasic postnatal growth curves in very-low-birth-weight infants. Although early enteral feeding was well tolerated in the study infants, the occurrence of feeding intolerance in some (36%) would suggest that additional parenteral nutrition may benefit some infants until full enteral feeding can be achieved.

Robinow syndrome: report of one case

We report a 2-month-old infant with Robinow syndrome. Clinical manifestations included short stature, characteristic facies, mesomelic brachymelia, brachydactyly, camptodactyly, duplication of thumbs, hypoplasia of clitoris, and deformed pronated foot. A cytogenetic study revealed a normal female karyotype. Chest radiography showed rib anomalies, a vertebral anomaly in T8, narrowing of interpedicular distances and flaring with slight thickening of the bone cortex in the bilateral humeral bone. Hand and foot radiography showed generalized shortening include unequal size of metacarpal, metatarsal and phalangeal bones. In our case, sporadic or autosomal recessive inheritance was most likely. The literature is reviewed.

Enhancement of EAE and induction of autoantibodies to T-cell epitopes in mice infected with a recombinant vaccinia virus encoding myelin proteolipid protein

SJL/J mice were infected with a recombinant vaccinia virus encoding myelin proteolipid protein (PLP) (VVplp). Antibody responses to whole PLP and to encephalitogenic peptides, p139-151, p178-191 or p104-117 were measured after vaccination and following challenge with these three PLP peptides. Competitive ELISAs showed that antibodies to p139-151 and p178-191 represented the majority of antibodies in the anti-PLP antibody response following VVplp vaccination, since the antibodies to intact PLP could be inhibited 56, 35 and 1%, respectively, by p139-151, p178-191 and p104-117. After peptide challenge, epitope specific anti-peptide antibodies were enhanced. These anti-peptide antibodies also reacted with the intact PLP molecule. Interestingly, the mean titer of anti-p139-151 antibody in p139-151 challenged mice was significantly higher than that observed for anti-p178-191 in p178-191 and for anti-p104-117 in p104-117 challenged mice. Following peptide challenge, the anti-PLP IgG response shifted from an IgG1 to an IgG2a and 2b phenotype. In these mice, both the clinical disease and histological pattern of experimental allergic encephalomyelitis (EAE) were enhanced. The enhancement was most pronounced in the pathologic scores in the p139-151 challenged group followed by p104-117 challenged mice. Thus, humoral immune responses to PLP encephalitogenic peptides can be generated with virus encoding a self central nervous system (CNS) protein.

Regulation of heme biosynthesis in Salmonella typhimurium: activity of glutamyl-tRNA reductase (HemA) is greatly elevated during heme limitation by a mechanism which increases abundance of the protein

In Salmonella typhimurium and Escherichia coli, the hemA gene encodes the enzyme glutamyl-tRNA reductase, which catalyzes the first committed step in heme biosynthesis. We report that when heme limitation is imposed on cultures of S. typhimurium, glutamyl-tRNA reductase (HemA) enzyme activity is increased 10- to 25-fold. Heme limitation was achieved by a complete starvation for heme in hemB, hemE, and hemH mutants or during exponential growth of a hemL mutant in the absence of heme supplementation. Equivalent results were obtained by both methods. To determine the basis for this induction, we developed a panel of monoclonal antibodies reactive with HemA, which can detect the small amount of protein present in a wild-type strain. Western blot (immunoblot) analysis with these antibodies reveals that the increase in HemA enzyme activity during heme limitation is mediated by an increase in the abundance of the HemA protein. Increased HemA protein levels were also observed in heme-limited cells of a hemL mutant in two different E. coli backgrounds, suggesting that the observed regulation is conserved between E. coli and S. typhimurium. In S. typhimurium, the increase in HemA enzyme and protein levels was accompanied by a minimal (less than twofold) increase in the expression of hemA-lac operon fusions; thus HemA regulation is mediated either at a posttranscriptional step or through modulation of protein stability.

Hepatic focal nodular hyperplasia: findings on color Doppler ultrasound

BACKGROUND

We assessed the color Doppler ultrasound (US) findings in focal nodular hyperplasia (FNH).

METHODS

Seven FNH lesions were imaged with color Doppler US and hepatic angiography.

RESULTS

In four lesions, color Doppler demonstrated a central stellate vascular appearance which correlated with central feeding artery with spoke-wheel sign angiographically. Except for one lesion, color Doppler US imaging correlated with angiographic findings.

CONCLUSIONS

Color Doppler US is capable of demonstrating the typical findings of a central feeding artery and stellate vascular pattern in many cases of FNH.

Clinical utility of color Doppler sonography in the differentiation of hepatocellular carcinoma from metastases and hemangioma

The clinical utility of color Doppler sonography in the differentiation of hepatocellular carcinoma from metastases and hemangioma was investigated in 72 hepatocellular carcinomas (80 lesions), 30 metastases (82 lesions), and 39 hemangiomas (54 lesions). Overlaps of color patterns were found among hepatocellular carcinoma, metastases and hemangioma. Pulsatile waves from lesions with the basket, vessels within tumor, or spot patterns, or lesions measuring less than 3 cm with detectable signals, did not favor the diagnosis of hemangioma. In conclusion, color Doppler sonography can aid in the differentiation of hepatocellular carcinoma from hemangioma but may be unreliable in the differentiation of hepatocellular carcinoma from hypervascular metastases.

The genotypes of hepatitis C virus in patients with chronic hepatitis C virus infection in southern Taiwan

To investigate the genotype distribution of hepatitis C virus (HCV) in southern Taiwan, the sera from 56 patients with chronic HCV infection were studied. Twenty-nine patients were men and 27 were women. Age ranged from 22 to 65 years (mean, 47.3 +/- 11.4). Eighteen of them had chronic persistent hepatitis, 27 had chronic active hepatitis, and 11 had liver cirrhosis. HCV RNA was detected by reverse transcription-nested polymerase chain reaction using primers derived from the 5'-noncoding region. The genotypes of HCV were determined by amplification of the core region with the type-specific primers as described by Okamoto et al.. All sera were positive for HCV RNA. The prevalence rates of genotypes were as follows: 1b/II, 44.6%(25/56); 2a/III, 41.1%(23/56); 2b/IV, 3.6%(2/56); mixed 1b/I + 2a/III, 5.4%(3/56): mixed 1b/II + 2b/IV, 1.8%(1/56) and type unclassified 3.6%(2/56). The distribution of genotypes was not related to the patients' age, sex, and histological changes. Nevertheless, patients having past history of blood transfusion had a significantly higher rate of HCV type 2a/III infection (72.2% versus 34.2%, p < .05, chi-square test). We concluded that both of the HCV genotypes 1 b/II and 2a/III are predominant types in southern Taiwan and regional HCV genotype distribution may differ even within this island. Selective transmission of specific genotypes may pass along different infectious routes.

Aflatoxin exposure and risk of hepatocellular carcinoma in Taiwan

To investigate the carcinogenic effect of environmental aflatoxin exposure, 56 cases of hepatocellular carcinoma (HCC) diagnosed between 1991 and 1995 were identified and individually matched by age, sex, residence and date of recruitment to 220 healthy controls from the same large cohort in Taiwan. Blood samples were analyzed for hepatitis B and C viral markers and for aflatoxin-albumin adducts; urine was tested for aflatoxin metabolites. We obtained information about sociodemographic characteristics, habitual alcohol drinking, cigarette smoking and diet in a structured interview. Hepatitis B virus surface antigen (HBsAg) carriers had a significantly increased risk for HCC. After adjustment for HBsAg serostatus, the matched odds ratio (ORm) was significantly elevated for subjects with high levels of urinary aflatoxin metabolites. When stratified into tertiles, a dose-response relationship with HCC was observed. The ORm for detectable aflatoxin-albumin adducts was not significant after adjustment for HBsAg serostatus. HBsAg-seropositive subjects with high aflatoxin exposure had a higher risk than subjects with high aflatoxin exposure only or HBsAg seropositivity only. In male HBsAg-seropositive subjects, adjusted ORs were 2.8 (95% confidence interval [CI] = 0.9-9.1) for detectable compared with non-detectable aflatoxin-albumin adducts and 5.5 (CI = 1.3-23.4) for high compared with low urinary aflatoxin metabolite levels. Our results suggest that environmental aflatoxin exposure may enhance the hepatic carcinogenic potential of hepatitis B virus. A large-scale study will be needed to evaluate the effect of aflatoxin exposure on HBsAg non-carriers.

Treatment of chronic hepatitis C with interferon-alpha: a preliminary report

Interferon alpha (IFN-alpha) has been indicated to be dramatically effective in some but not all patients with chronic hepatitis C virus (HCV) infection. We investigated prospectively 27 patients of chronic hepatitis C, 12 females and 15 males, treated with IFN-alpha for a better regimen of the therapy and for any effective predictor of response to the treatment. All patients were treated with 3 to 6 million units (MU) of recombinant IFN-alpha 2b (n = 15) or lymphoblastoid IFN-alpha (n = 12) given 3 times weekly for 12 to 36 weeks. Patients with normal alanine aminotransferase (ALT) value during therapy, who sustained this response throughout 6 months follow-up after treatment was completed, were grouped into the complete responders. Patients with normal ALT value during therapy but who relapsed after treatment completed, were grouped as partial responders. Non-responders were defined as patients without normal ALT value during therapy. The rates of complete response, partial response, and non-response were 29.6%, 40.8%, and 29.6%, respectively. The degree of response to IFN-alpha therapy was not related to age, sex, type of IFN-alpha, history of blood transfusion, the state of liver pathology, or pretreatment level of ALT value. The complete responsive rate to IFN-alpha was higher in patients treated with total dose above 215 MU [38.1% (8/21) vs. 0% (0/6), p = 0.06], in patients treated for at least 24 weeks [40% (8/20) vs. 0% (0/7), p < 0.05], and in patients with non-genotype 1b/II HCV infection [40% (8/20) vs. 0% (0/7), p < 0.05]. We concluded that IFN-alpha was effective in the treatment of chronic HCV infection, particularly in those other than HCV genotype 1b/II. A high-dose, and long-duration regimen may be recommended for better response of chronic hepatitis C to IFN-alpha therapy.

Elevated aflatoxin exposure and increased risk of hepatocellular carcinoma

To elucidate the importance of aflatoxin in the etiology of hepatocellular carcinoma (HCC), a community-based cohort study combined with molecular dosimetry of aflatoxin exposure was performed in the Penghu Islets where the HCC mortality rate is highest in Taiwan. A total of 6,487 residents aged 30 to 65 years were recruited in the two-stage screening survey and underwent regular follow-up examination. Among 33 newly diagnosed HCC cases, 31 (94%) were chronic hepatitis B surface antigen (HBsAg) carriers and 3 (9%) were positive for antibodies against hepatitis C virus (HCV). Among 20 HCC patients and 86 matched healthy controls whose serum samples were tested for aflatoxin B1 (AFB1)-albumin adducts by competitive enzyme-linked immunosorbant assay (ELISA), 13 (65%) HCC patients and 32 (37%) matched controls were seropositive, showing a statistically significant multivariate-adjusted odds ratio of 5.5 with a 95% confidence interval of 1.2 to 24.5. The results imply the elevated risk of HCC among Penghu residents may be attributable to their heavy exposure to aflatoxins and high HBsAg carrier rate.

Aflatoxin exposure and risk of hepatocellular carcinoma in Taiwan

To investigate the carcinogenic effect of environmental aflatoxin exposure, 56 cases of hepatocellular carcinoma (HCC) diagnosed between 1991 and 1995 were identified and individually matched by age, sex, residence and date of recruitment to 220 healthy controls from the same large cohort in Taiwan. Blood samples were analyzed for hepatitis B and C viral markers and for aflatoxin-albumin adducts; urine was tested for aflatoxin metabolites. We obtained information about sociodemographic characteristics, habitual alcohol drinking, cigarette smoking and diet in a structured interview. Hepatitis B virus surface antigen (HBsAg) carriers had a significantly increased risk for HCC. After adjustment for HBsAg serostatus, the matched odds ratio (ORm) was significantly elevated for subjects with high levels of urinary aflatoxin metabolites. When stratified into tertiles, a dose-response relationship with HCC was observed. The ORm for detectable aflatoxin-albumin adducts was not significant after adjustment for HBsAg serostatus. HBsAg-seropositive subjects with high aflatoxin exposure had a higher risk than subjects with high aflatoxin exposure only or HBsAg seropositivity only. In male HBsAg-seropositive subjects, adjusted ORs were 2.8 (95% confidence interval [CI] = 0.9-9.1) for detectable compared with non-detectable aflatoxin-albumin adducts and 5.5 (CI = 1.3-23.4) for high compared with low urinary aflatoxin metabolite levels. Our results suggest that environmental aflatoxin exposure may enhance the hepatic carcinogenic potential of hepatitis B virus. A large-scale study will be needed to evaluate the effect of aflatoxin exposure on HBsAg non-carriers.

A natural kinase-deficient variant of fibroblast growth factor receptor 1

A fibroblast growth factor receptor 1 variant missing 37 amino acids from the carboxy-terminal tyrosine kinase catalytic domain was discovered in human lung fibroblasts and several other human cell lines. The receptor variant binds specifically to acidic fibroblast growth factor but has no tyrosine kinase activity. It was found that cellular transfectants expressing the fibroblast growth factor receptor 1 variant are mitogenically inactive and ligand binding to the receptor causes neither receptor autophosphorylation nor phospholipase C-gamma transphosphorylation. The fibroblast growth factor receptor 1 variant therefore represents an inactive receptor for acidic fibroblast growth factor. Since both kinase and kinase-deficient receptor forms are expressed in cells, it is conceivable that the kinase-deficient receptor plays an important role in regulating cellular responses elicited by acidic fibroblast growth factor stimulation.

[A histopathologic study on recovering effect of kangdu shengxue decoction on spleen and thymus of mice with radiation injury]

The effect of Kangdu Shengxue Decoction (KDSXD) on the spleen and thymus of mice irradiated with 80Co gamma-rays has been studied by histopathological methods. 130 LACA mice were divided into 3 groups. Control and experimental groups were generally irradiated for once with 8 Gy 80Co gamma-rays. The experiment of group were treated with KDSXD one hour before irradiation and consecutively five days after radiation. The results of experiment showed that 30 days after irradiation the structure of spleen and thymus of treated mice normalized. The difference of recovery between control and experimental group showed a high significance statistically (P < 0.01).

Changes in intrahepatic portal hemodynamic in early stage hepatic abscesses

Color Doppler sonography was used to investigate the changes in intrahepatic portal hemodynamics in early stage hepatic abscesses (21 lesions). At time of patients' admission, 10 lesions measuring over 6 cm showed reverse flow from at least one of their corresponding segmental portal branches, but 11 lesions measuring 6 cm or less did not show this phenomenon. All portal branches with reverse flow eventually returned to a normal direction of flow after successful medication. In conclusion, a large early stage hepatic abscess may show temporary reverse portal flow on color imaging. Thus, a differential diagnosis of hepatic tumors with reverse portal flow should include early stage hepatic abscesses.

The status of serum hepatitis B virus DNA in HBSAG-positive hepatocellular carcinoma

To elucidate the status of serum hepatitis B virus (HBV) DNA in HBsAg-positive hepatocellular carcinoma (HCC), 100 type B chronic liver disease (CLD) patients and 19 HCC patients were studied. The positive rate of serum HBV DNA in HBeAg-positive CLD patients was significantly higher than that in HBeAg-negative CLD patients, and the correlation between the presence of serum HBV DNA and patients' age showed a negative trend. In contrast, the positive rates of serum HBV DNA in HCC patients were not related to the status of HBeAg and age, and the positive rate of serum HBV DNA in HBeAg-negative HCC patients was significantly higher than that in HBeAg-negative CLD patients. Nevertheless, the serum concentrations of HBV DNA in HCC patients were significantly lower than those in CLD patients. These results suggest that replication of HBV in HCC patients might differ from that in CLD patients, and that persistent low-level HBV replication might be related to the presence of HCC.

Elevated aflatoxin exposure and increased risk of hepatocellular carcinoma

To elucidate the importance of aflatoxin in the etiology of hepatocellular carcinoma (HCC), a community-based cohort study combined with molecular dosimetry of aflatoxin exposure was performed in the Penghu Islets where the HCC mortality rate is highest in Taiwan. A total of 6,487 residents aged 30 to 65 years were recruited in the two-stage screening survey and underwent regular follow-up examination. Among 33 newly diagnosed HCC cases, 31 (94%) were chronic hepatitis B surface antigen (HBsAg) carriers and 3 (9%) were positive for antibodies against hepatitis C virus (HCV). Among 20 HCC patients and 86 matched healthy controls whose serum samples were tested for aflatoxin B1 (AFB1)-albumin adducts by competitive enzyme-linked immunosorbant assay (ELISA), 13 (65%) HCC patients and 32 (37%) matched controls were seropositive, showing a statistically significant multivariate-adjusted odds ratio of 5.5 with a 95% confidence interval of 1.2 to 24.5. The results imply the elevated risk of HCC among Penghu residents may be attributable to their heavy exposure to aflatoxins and high HBsAg carrier rate.

Longitudinal study of intrahepatic portal flow: a novel approach using Doppler technique

The present study investigates whether the application of the summation of portal blood flow (SPBF), measured from the left umbilical portion and the right anterior branch by Doppler, could be of use in the longitudinal study of intrahepatic portal flow or not. Forty-five subjects were divided into two groups. Group I subjects included males and post-menopausal females. Thirty-seven subjects (19 normal volunteers, 12 subjects with chronic hepatitis, six cirrhotics) were investigated by the more experienced doctor A at 9 day intervals for an intra-observer study. Among them, seven subjects (four normal volunteers, three with chronic hepatitis) were also investigated consecutively at 10 min apart by doctor B on days 1 and 10 for an interobserver study. Group II subjects included eight normal subjects with a regular menstrual cycle. They were investigated by doctor A during menstruation, mid-follicular, ovulatory and mid-luteal phases of the menstrual cycle to evaluate the possible impact of the menstrual cycle on SPBF measurement. The reproducibility of measurements was assessed by the coefficient of variation (CV) and the reproducibility coefficient. Data are expressed as mean +/- s.d. The CV of the SPBF for intra-observer and interobserver study were 4.88 +/- 3.36 and 4.19 +/- 2.53, respectively. All differences of SPBF were within their corresponding reproducibility limits. The results of SPBF measurements obtained from different phases of the menstrual cycle were variable. Only the comparison between the data obtained from mid-follicular and mid-luteal phases could demonstrate acceptable CV values (3.98 +/- 3.12%) and all the differences in SPBF measurements were within the repeatability limit. In conclusion, Doppler SPBF measurement may be useful in the longitudinal evaluation of intrahepatic portal flow changes.

Immunohistochemical quantitation of 4-aminobiphenyl-DNA adducts and p53 nuclear overexpression in T1 bladder cancer of smokers and nonsmokers

An immunoperoxidase method, using a monoclonal antibody which recognizes 4-aminobiphenyl (4-ABP)-DNA adducts, was developed for the detection and quantitation of DNA damage in bladder tissue and applied to stored paraffin blocks of transurethral resection specimens of 46 patients with T1 bladder cancer. Mean relative staining intensity for 4-ABP-DNA adducts was significantly higher in current smokers (275 +/- 81, n = 24) compared to nonsmokers (113 +/- 71, n = 22) (P < 0.0001). There was a linear relationship between mean levels of relative staining and number of cigarettes smoked with lower levels in the 1-19 cig/day group (205 +/- 30, n = 5), compared to the 20-40 (289 +/- 40, n = 7) and the >40 cig/day group (351 +/- 57, n = 3)(P < 0.001). Nuclear overexpression of p53, analyzed by immunoperoxidase staining, was observed in 27 (59%) of the 45 stage T1 tumors analyzed. There was a significant correlation between p53 overexpression and recurrence of disease (odds ratio = 12.3, P < 0.01). Nuclear staining of p53 was also correlated with smoking status, cig/day and 4-ABP-DNA adducts. This work demonstrates that the immunohistochemical method has sufficient sensitivity for detection of 4-ABP-DNA adducts in human bladder samples. The method has several advantages including small sample size, the possibility of retrospective analysis of stored paraffin blocks, the ability to analyze binding in specific cell types, and a relatively low cost.

Treatment of hepatocellular carcinoma smaller than 5 cm by transcatheter arterial chemoembolization

To assess the effectiveness of transcatheter arterial chemoembolization (TACE) in the treatment of small hepatocellular carcinoma (HCC) and to analyze the prognostic factors, a total of 77 patients with histologically proven HCC, < or = 5 cm in diameter, were enrolled for the study and followed for more than 2 years, The overall cumulative 1-, 2-, and 3-year survival rates were 79.2%, 50.6% and 36.7%, respectively. The median survival time of Child-Pugh's A patients was 990 +/- 146 days, which was significantly better than the median survival time of Child-Pugh's B patients (450 +/- 82 days) Furthermore, positive HBeAg and alpha-Fetoprotein (AFP) were factors close to statistically significant. In contrast, sex, age, HBsAg, Anti-HCV, tumor type, tumor size and tumor number were not related to the prognosis in small HCC who received TACE.

p53 mutations in gastric cancers from Taiwan

Mutations of the p53 gene were investigated in 80 surgical specimens of primary gastric cancer by polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) analysis. Mutations were detected in 18 tumors (22.5%) and localized to exons 5, 7 and 8. Mutations did not follow a random distribution among different subtypes, but instead clustered in the group of papillary adenocarcinomas, in which 7/12 (58.3%) cases were mutated. Positivity for p53 mutation was significantly higher in intestinal-type (37.5%) than in diffuse-type carcinomas (12.5%). These results suggest that gene alterations of p53 are not rare and may participate in the carcinogenesis of intestinal-type carcinomas of the stomach. Twenty of 21 p53 mutations were represented by single nucleotide changes, mostly missense mutations (19 events) and one nonsense mutation. Transversional mutations constitute the majority of p53 mutations (65%) and only 20% of mutations show G:C to A:T transitions. It is possible that the etiologies of gastric cancer in different geographical areas are different.

The 30 kDa protein co-purified with chick liver glutathione S-transferases is a carbonyl reductase

An unidentified 30 kDa protein was co-purified with chick liver glutathione S-transferases from S-hexylglutathione affinity column. The protein was isolated to apparent homogeneity with chromatofocusing. The molecular mass of the protein was determined to be 30 277 +/- 3 dalton by mass spectrometry. The protein was digested with Achromobacter proteinase I. Amino-acid sequence analyses of the resulting peptides show a high degree of identity with those of human carbonyl reductase. The protein is active with menadione as substrate. Thus, it is identified as chick liver carbonyl reductase.

Percutaneous intravascular ethanol injection of the supplying tumor vessel in the treatment of hepatocellular carcinoma larger than 3 cm

Percutaneous intravascular ethanol injection of the supplying vessel of the tumor using color Doppler imaging was performed in three patients (three lesions) with hepatocellular carcinoma measuring more than 3 cm. Intravascular injection was achieved in six out ot seven attempts. The total amount of ethanol injected intravascularly was small (10, 15,0 and 26 ml for each patient). One attempt failed and the ethanol was injected perivascularly. No serious complication was noted. After treatment, two patients showed remarkable decrease in tumor size and one showed massive tumor necrosis. In conclusion, ethanol injection using the intravascular approach may be of value in the palliative management of large hepatocellular carcinomas.

Virus encoding an encephalitogenic peptide protects mice from experimental allergic encephalomyelitis

The association of viral infections with autoimmune central nervous system (CNS) diseases such as post-infectious encephalomyelitis and possibly multiple sclerosis (MS) prompted the investigation to understand how virus infection could modulate autoimmune responses. Recombinant vaccinia viruses encoding an encephalitogenic portion of myelin basic protein (MBP) were evaluated in an animal model for human demyelinating disease, experimental allergic encephalomyelitis (EAE). We have determined that mice vaccinated with recombinant viruses encoding an encephalitogenic region of MBP were protected from EAE. In vivo depletion of CD8+ T cells did not abrogate this protection, suggesting lack of regulation by this cell type. These studies demonstrate that virus infection may be a means to modulated immune responsiveness to CNS disease.

Seroepidemiology of Helicobacter pylori among adolescents in Taiwan

Helicobacter pylori has been documented to be associated with chronic type B gastritis, peptic ulcer and gastric cancer. In order to examine the seroprevalence and risk factors for Helicobacter pylori infection in Taiwan, a total of 871 adolescents were selected randomly from junior high school children in 20 study precincts and townships. Serum samples collected were tested for IgG antibodies against Helicobacter pylori by enzyme-linked immunosorbent assay using commercial kits. The overall seropositive rate was 21.1% showing no gender difference. There was a striking geographical variation in seroprevalence of Helicobacter pylori infection ranging from 4.6% to 37.1% in 20 precincts and townships. The seroprevalence was highest in the north (25.4%), medium in central Taiwan (21.9%), and lowest in the south (18.7%). The higher the age-adjusted mortality from gastric cancer in a given study area, the higher the seroprevalence of Helicobacter pylori in the area. Metropolitan and aboriginal areas had higher seroprevalences than urban and rural areas, but the difference was not statistically significant. The seroprevalence was higher for those who had no sibling (29.4%) or had a sibship size of > or = 6 (31.1%) than for those with a sibship size of 1-5 (20.0%), but the difference was not statistically significant either.

Protection against oxidative injury and permeability alteration in cultured alveolar epithelium by transferrin-catalase conjugate

The successful prevention of hydrogen peroxide-induced alveolar permeability alterations and cell injury by transferrin-catalase conjugate is described in this study. Permeability alterations and cell injury were induced in cultured alveolar epithelial monolayers by hydrogen peroxide. Transepithelial transport of a permeability marker, [14C] mannitol, and cellular nuclear fluorescence of a membrane integrity indicator, propidium iodide, were used to quantitate epithelial permeability and damage respectively. Hydrogen peroxide (0.1 - 10 mM) induced a dose-dependent increase in both alveolar permeability and cellular damage; however, the oxidant effect on monolayer permeability did not require prior cell damage. Electron spin resonance measurements using the spin trap 5,5-dimethyl-l-pyrroline-N-oxide indicated the formation of hydroxyl radicals in hydrogen peroxide-treated cells. Chelation of the cellular pool of iron by deferoxamine inhibited radical formation and helped protect the cells from oxidative changes. Prior treatment of the cells with catalase (0.1 U-10 U/ml) had minimal protective effects on cell injury and permeability alterations. In contrast, transferrin-catalase conjugate, at the same concentration range, exhibited much improved protective effects on the cells in response to oxidant stress. This enhanced protection was found to correlate well with an increase in cellular uptake of the enzyme conjugate via the transferrin receptor endocytosis pathway. Effective protection by the enzyme conjugate was shown to require both the antioxidant enzyme moiety and the cognate moiety for the cell surface receptor. These findings indicate the potential therapeutic merit of transferrin-catalase conjugate for the treatment of pathological processes in the lung, whenever oxidative stress is involved.

Inhibition by nystatin of Kv1.3 channels expressed in Chinese hamster ovary cells

The patch-clamp technique was used to study the effects of nystatin on a cloned delayed rectifier potassium channel (Kv1.3) expressed in Chinese hamster ovary (CHO) cells. Kv1.3 currents recorded in the whole-cell configuration, using an intracellular solution containing nystatin, were subjected to a time- and concentration-dependent reduction in their amplitude and in the time constants of apparent inactivation. Direct application of nystatin to the cytoplasmic side of excised inside-out patches inhibited Kv1.3 currents and this inhibition was immediately reversible upon washout of the drug. In contrast, currents mediated by another delayed rectifier (Kv3.1) were not affected by this drug. The concentrations for nystatin and its structural analog, amphotericin B, required to produce half maximal inhibition (IC50) of the current were estimated to be about 3 and 60 microM, respectively. The effects of nystatin on the amplitude and inactivation of Kv1.3 currents were not voltage-dependent. In inside-out patches, tetraethylammonium (TEA) produced a rapid block of Kv1.3 currents upon the onset of a voltage pulse, while the inhibition by nystatin developed slowly. When co-applied with TEA, nystatin potentiated the extent of the TEA-dependent block, and the kinetic effect of nystatin was slowed by TEA. In summary, nystatin, a compound frequently used in perforated patch recordings to preserve intracellular dialyzable components, specifically inhibited the potassium channel Kv1.3 at concentrations well below those required for perforation. The site of this inhibition may be different from that for TEA and is readily accessible from the cytoplasmic side of the membrane.

[Community-based hepatocellular carcinoma screening in seven townships in Taiwan]

The early detection and prompt treatment of hepatocellular carcinoma (HCC) may prolong life and improve the quality of life of affected patients. In order to compare sensitivity and specificity of various screening biomarkers, identify subjects with a high risk of developing HCC, and estimate prevalence and incidence of HCC among subjects, a community-based HCC screening program was implemented in Sanchi, Chutung, Potzu, and Kaohsu, Taiwan Island as well as Makung, Huhsi and Paihsa in Penghu Islets. First stage screening of HCC was based on serological markers including hepatitis B surface antigen (HBsAg), antibody against hepatitis C virus (anti-HCV), alpha-fetoprotein (AFP > or = 20 ng/mL), alanine transaminase (> or = 40 IU/L), and aspartate transaminase (> or = 45 IU/L); as well as history of liver cirrhosis or HCC among first-degree relatives. Subjects who were positive for at least one of above six first-stage criteria were referred for second-stage screening by abdominal ultrasonography. Confirmatory diagnosis of HCC was made in suspicious cases according to aspiration cytology surgical pathology, digital substracted angiogram and/or computed tomography. A total of 12,026 men in seven study townships and 1,800 women in two townships in Penghu were recruited for first-stage screening (response rate: men, 25.5%; women, 46.8%). The positive rates for first-stage screening were 30.9% men and 34.6% women. The response rates for second-stage screening were 91% men and 90.5% women. Age-standardized prevalence of HCC per 1,000 subjects was 5.2 for men and 0.8 for women in Penghu Islets and 1.2 for men on Taiwan island. Among five serological biomarkers, HBsAg carrier status had the highest sensitivity (88.2%) and AFP had the second highest sensitivity (43.1%). The specificity of these markers was highest for AFP (99.0%) and lowest for HBsAg carrier status (80.3%). There were 16 new HCC cases identified after an intensive follow-up of 137 cases affected with liver cirrhos is giving an annual HCC incidence rate of 5.3%, while the rate for non-cirrhotic subjects who were positive on first-stage screening was only 0.15%. The combination of HBsAg and AFP for the first-stage screening and abdominal ultrasonography for the second-state screening seems valid for the early detection of HCC, but its cost-effectiveness remains to be elucidated by a longer follow-up study.

[Community-based cervical cancer screening in seven townships in Taiwan]

Cervical cancer is the leading malignant neoplasm in women in Taiwan. In order to compare the validity of various cervical neoplasia screening methods, estimate the prevalence of low- and high-grade squamous intraepithelial lesions (LSIL and HSIL), and identify risk factors for LSIL and HSIL, a community-based cervical neoplasia screening program was implemented in Sanchi, Chutung, Potzu, Kaohsu, Makung, Huhsi, and Paihsa townships, Taiwan. Both cervical smears and cervicograms were used for the screening of cervical neoplasia. Subjects who had positive cervical smears, cervicogram, or both, were further confirmed by colposcopy-guided biopsy. A total of 10,628 married women aged 30 to 64 years were recruited from seven study townships which gave a response rate of 25.2%. Among 667 subjects who screened positive, 555 (82%) underwent colposcopy-guided biopsy. The age-adjusted prevalence was 3.4% for LSIL and 1.7% for HSIL. The biopsy-confirmed rates for cervical smear-detected LSIL and HSIL were 62.8% and 80.6%, respectively; while 56.6% of minor lesions and 22.2% of major lesions identified by cervicogram were biopsy-confirmed as LSIL and HSIL, respectively. The sensitivity of detecting LSIL was higher for cervicograms (79.3%) than for cervical smears (16.7%), and cervicograms had a lower sensitivity in detecting HSIL (48.4%) than cervical smears (90.0%). Multiple logistic regression analysis showed a striking geographical variation in prevalence of LSIL and HSIL. The prevalence of LSIL decreased with the increase in age, and increased with the duration of taking oral contraceptives. The prevalence of HSIL increased with the parity and the duration of taking oral contraceptives and was also significantly associated with the history of cervical cancer among mother and sisters. It is suggested that improvements in the participation rate of cervical neoplasia screening would promote women's health in Taiwan.

Green-tea consumption and risk of stomach cancer: a population-based case-control study in Shanghai, China

The effect of drinking Chinese green tea on the risk of stomach cancer was evaluated in a population-based case-control study conducted in Shanghai, China, from October 1991 to December 1993. Eligible cases were incident cases of primary stomach cancer diagnosed during the study period among residents of Hongkou district and Nanhui county aged under 80 years. Controls were selected from the same street or commune where the case resided and were matched to the cases on age (within three years) and gender. A total of 711 cases and 711 matched controls, more than 90 percent of the eligible subjects, completed the interview. Information was obtained on the types of tea used, age when habitual tea drinking started, frequency of new batches of tea leaves used per day, number of cups brewed from each batch, total duration of drinking for each batch, strength and temperature of the tea consumed. Statistical analysis was based on modelling through conditional logistic regression. After adjusting for age, gender, place of residence, education, birthplace, alcohol consumption, and cigarette smoking, the odds ratio (OR) comparing drinkers of green tea with nondrinkers was 0.71 (95 percent confidence interval = 0.54-0.93). The adjusted OR decreased with increasing number of new batches of the green tea consumed each day (P value trend = 0.006). With the largest series of stomach cancer cases to date, this study found green-tea consumption associated with lower risk of stomach cancer. Among drinkers of green tea, the risk of stomach cancer did not depend on the age when habitual green-tea drinking started. Green tea may disrupt gastric carcinogenesis at both the intermediate and the late stages.

Prevalence and size of simple hepatic cysts in Taiwan: community- and hospital-based sonographic surveys

Simple hepatic cysts are now being diagnosed more frequently with the widespread availability of sonographic imaging. Among the general population, the prevalence was reported to be between 0.1 and 2.5%, more so in women, and more often in the right lobe. We conducted this large scale community-based sonographic screening on simple hepatic cysts to explore the age- and sex-specific prevalence in Taiwan. We also conducted another hospital-based study to record the size of simple hepatic cysts. A total of 3,600 subjects in 8 communities were recruited and 156 simple hepatic cysts in 132 study subjects were detected. The overall prevalence is 3.60%. An increasing prevalence with age is demonstrated, ranging from 0.83% from below the age of 40 up to 7.81% of patients over 60 years old. The sizes of 219 simple hepatic cysts of 167 patients out of the hospital-based 5,893 patients were recorded in detail; 53% of cysts were of a diameter of between 1 and 3 cm, and only 7% were larger than 5 cm.

Inhibition by propofol (2,6 di-isopropylphenol) of the N-methyl-D-aspartate subtype of glutamate receptor in cultured hippocampal neurones

1. The effects of propofol (2,6 di-isopropylphenol) on responses to the selective glutamate receptor agonists, N-methyl-D-aspartate (NMDA) and kainate, were investigated in cultured hippocampal neurones of the mouse. Whole cell and single channel currents were recorded by patch-clamp techniques. Drugs were applied with a multi-barrel perfusion system. 2. Propofol produced a reversible, dose-dependent inhibition of whole cell currents activated by NMDA. The concentration of propofol which induced 50% of the maximal inhibition (IC50) was approximately 160 microM. The maximal inhibition was incomplete leaving a residual current of about 33% of the control response. This inhibitory action of propofol was neither voltage- nor use-dependent. 3. Analysis of the dose-response relation for whole cell NMDA-activated currents indicated that propofol caused no significant change in the apparent affinity of the receptor for NMDA. 4. Outside-out patch recordings of single channel currents evoked by NMDA (10 microM) revealed that propofol (100 microM) reversibly decreased the probability of channel opening but did not influence the average duration of channel opening or single channel conductance. 5. Whole-cell currents evoked by kainate (50 microM) were insensitive to propofol (1 microM-1 mM). 6. These results indicate that propofol inhibits the NMDA subtype of glutamate receptor, possibly through an allosteric modulation of channel gating rather than by blocking the open channel. Depression of NMDA-mediated excitatory neurotransmission may contribute to the anaesthetic, amnesic and anti-convulsant properties of propofol.

Electrophysiological and pharmacological characterization of a mammalian Shaw channel expressed in NIH 3T3 fibroblasts

1. The Shaw-like voltage-activated potassium channel Kv3.1 is expressed in neurons that generate rapid trains of action potentials. By expressing this channel in a mammalian cell line and by simulating its activation, we tested the potential role of this channel in action potential repolarization. 2. NIH 3T3 fibroblasts were stably transfected with Kv3.1 DNA. Currents recorded in these cells had a threshold of activation at approximately -10 mV, showed little inactivation, and were very sensitive to blockade by 4-aminopyridine and tetraethylammonium. 3. Kv3.1 currents activated rapidly at the onset of depolarizing voltage pulses. After an initial rapid phase of activation, which could be fit by an n4 Hodgkin-Huxley model, Kv3.1 currents expressed in fibroblasts had a second, slower phase of activation, and, in some cells, a slower phase of partial inactivation, both of which could be fit with modified n4p models. 4. Cell-attached single-channel recordings indicated that the Kv3.1 channel displays two gating behaviors, a short-open-time pattern, which occurs only at the onset of depolarization, and a long-open-time pattern, which predominates during prolonged depolarizations. 5. The amplitude of Kv3.1 currents, and the probability of channel openings, was reduced by a phorbol ester activator of protein kinase C, and the action of this agent was blocked by preincubation with the protein kinase inhibitor H7 (1-[5-isoquinolinesulfonyl]-2-methyl piperazine). In contrast, the effects of dioctanoyl glycerol, which also attenuated the currents, could not be completely blocked by H7, suggesting that diacylglycerols may act on the channel by a kinase-independent pathway. 6. Incorporation of a current with the kinetics and voltage dependence of Kv3.1 currents into a model cell with a sustained inward current showed that, in contrast to other delayed-rectifier currents such as the Shaker-like Kv1.1 and Kv1.6 channels, the level of expression of Kv3.1 currents could be varied over a wide range without attenuation of action potential height. Our results suggest that the Kv3.1 channel may provide rapidly firing neurons with a high safety factor for impulse propagation.

Modulation by magnesium of the affinity of NMDA receptors for glycine in murine hippocampal neurones

1. The effects of the divalent cation Mg2+ on NMDA currents recorded from cultured fetal mouse and acutely isolated neonatal rat hippocampal neurones were studied using the whole-cell patch-clamp technique. 2. Current-voltage relations were measured in the presence or absence of applied Mg2+ and added glycine. NMDA-evoked currents were studied in the absence or in a low concentration (0.2 mM) of applied Ca2+ in order to minimize Ca(2+)-dependent inactivation of the responses. Mg2+ unexpectedly enhanced NMDA-activated currents at positive membrane potentials. At negative membrane potentials Mg2+ caused a previously characterized voltage-dependent block of inward NMDA-activated currents. 3. The potentiation by Mg2+ of outward currents activated by NMDA was concentration dependent (EC50, approximately 3 mM; Hill coefficient, approximately 2). Mg2+ also reduced the desensitization of the NMDA receptor. The maximal enhancement of steady-state NMDA-activated currents was 2.7-fold and at 6 mM the time constant of desensitization was doubled. 4. Comparisons of concentration-response curves for glycine and 7-chloro-kynurenic acid demonstrated that Mg2+ significantly increased the affinity of the NMDA receptor for glycine. The EC50 for glycine was 380 nM in the absence of Mg2+ and 163 nM in 3 mM Mg2+. Mg2+ had little effect on the forward rate of the glycine response but halved the off-rate (2.34 to 1.15 s-1) and thus similarly reduced the apparent dissociation constant. 5. There was a good correlation between the concentration of extracellular Ca2+ and a reduction in the time constant of the glycine-sensitive component of NMDA receptor desensitization. Ca2+ could enhance these NMDA-activated currents briefly following exposure to high concentrations of Ca2+. These results are consistent with a Ca(2+)-dependent enhancement of the affinity of the NMDA receptor for glycine. 6. Mg2+ can enhance NMDA-mediated currents and reduce desensitization of this receptor by allosterically interacting with the glycine binding site. This interaction may be a key physiological mechanism through which modulation of the NMDA receptor is achieved.

Mass spectrometric analysis of rat liver cytosolic glutathione S-transferases: modifications are limited to N-terminal processing

Cytosolic glutathione S-transferases (GSTs) from rat livers were purified using an S-hexylglutathione affinity column. The GST subunits were resolved by reverse-phase HPLC and their molecular masses were determined by electrospray mass spectrometry. The major hepatic GSTs detected were subunits 1, 1', 2, 3 and 4, with molecular mass of 25,520, 25,473, 25,188, 25,782 and 25,571 Da respectively. Subunits 6, 7 and 10 are minor components, with molecular mass of 25,551, 23,308 and 25,211 Da respectively. Alternatively, the hepatic GSTs were purified using a glutathione affinity column. Subunits 1, 1', 2, 8 and 10 were eluted from this column with GSSG, the oxidized form of glutathione. Subunit 8 has a molecular mass of 25,553 Da. The remaining proteins on the glutathione affinity column were removed with glutathione and S-hexylglutathione. Subunits 2, 3, 4 and 6 could be detected in the eluate. We could not detect any significant difference in molecular mass between GSTs isolated from male and female rat livers. Cytosolic GSTs were isolated from livers of buthionine sulphoximine-treated female rats for MS analysis. The molecular masses obtained were identical to those determined for the controls.

A nested case-control study on the association between Helicobacter pylori infection and gastric cancer risk in a cohort of 9775 men in Taiwan

A nested case-control study was carried out to investigate the association between Helicobacter pylori infection and gastric cancer risk in Taiwan. A total of 29 patients newly affected with gastric cancer and 220 healthy controls matched with cases on age, sex and residence were selected from a cohort of 9,775 men recruited from 1984 through 1986. Frozen serum samples collected at recruitment examination were tested for IgG antibodies against Helicobacter pylori by an enzyme-linked immunosorbent assay. The average interval between serum collection and cancer diagnosis was 3.1 years. Gastric cancer cases had a higher seropositive prevalence (69%) than matched controls (59%) giving an odds ratio of 1.6 (95%) confidence interval = 0.7-2.6). Compared with previous nested case-control studies, Helicobacter pylori infection in early childhood may be a risk factor for gastric cancer. However, a long induction period seems required for gastro-carcinogenesis associated with Helicobacter pylori infection.

Ecological study of association between Helicobacter pylori infection and gastric cancer in Taiwan

The association between Helicobacter pylori infection and gastric cancer remains controversial. A community-based serosurvey was carried out in Taiwan to investigate the association. Serum IgG antibodies against Helicobacter pylori were examined in 728 subjects randomly selected from three townships with different gastric cancer mortality rates. The overall seropositivity of Helicobacter pylori was 54.7% (398/728) with no gender difference (males: 54.5%; females: 54.8%). The seroprevalence of Helicobacter pylori progressively increased with age in all three study townships. The age-specific seropositivity of Helicobacter pylori correlated well with age-adjusted gastric cancer mortality in the three townships. The difference in seropositivity was more profound in younger age groups. The ecological study in Taiwan suggests an association between Helicobacter pylori infection and gastric cancer. Helicobacter pylori infection in early childhood may be a key issue; in addition, a long induction time appears to be required for gastric carcinogenesis.

Modification of glutathione S-transferase 3-3 mutants with 2-(S-glutathionyl)-3,5,6-trichloro-1,4-benzoquinone. Identification of the C-terminal tryptic fragment as part of the H-site and evidence that 2-(S-glutathionyl)-3,5,6-trichloro-1,4-benzoquinone is not specific for cysteine labelling

A triple mutant of rat liver glutathione S-transferase 3-3 that has all three cysteine residues replaced with serine (CallS) and a quadruple mutant with a Tyr-115 to phenylalanine substitution on CallS (CallSY115F) were reacted with 2-(S-glutathionyl)-3,5,6-trichloro-1,4-benzoquinone (GS-1,4-TCBQ). The modified proteins were analysed on a triple-quadrupole mass spectrometer equipped with an electrospray ionization source. At an enzyme: GS-1,4-TCBQ ratio of 1:10, the enzymes were modified at multiple sites. Covalent attachment of a single inhibitor on to the protein was achieved by lowering the enzyme: GS-1,4-TCBQ ratio to 1:1. Results from m.s. analyses suggest that the inhibitor on the CallSY115F mutant exists as a glutathionyl dichlorobenzoquinone derivative. The modifiers of the CallS mutants are glutathionyl monochlorobenzoquinone derivatives. Therefore, GS-1,4-TCBQ reacts at a single site on CallSY115F, but probably cross-links two regions on wild-type and CallS mutant. To confirm our observation, CallS was modified with 1-chloro2,4-dinitrobenzene, which specifically labels Tyr-115, before reacting with GS-1,4-TCBQ. The inhibitor formed a glutathionyl dichlorobenzoquinone adduct on the dinitrophenyl-CallS mutant. In addition, the benzoquinone derivative on the protein can be partially removed by 1-chloro-2,4-dinitrobenzene. Peptide mapping and sequencing analysis of the GS-1,4-TCBQ-modified CallS mutant revealed that the C-terminal 16-amino-acid fragment is labelled. Molecular modelling suggests the C(5) and C(6) on the benzoquinone ring of the inhibitor interact with the oxygen atoms of Tyr-115 and Ser-209 respectively.

Targeted gene delivery to alveolar macrophages via Fc receptor-mediated endocytosis

Alveolar macrophage (AM) plays important roles in lung homeostasis and pathogenesis of diseases. The study of macrophage gene function and regulation as well as its potential therapeutic intervention will require the development of vectors capable of safe and efficient transfer of DNA to the AM. In the present study, we report a new transfection system that utilizes Fc receptor-mediated endocytosis as a means to target DNA to the AM. This system employs molecular conjugates consisting of a cognate moiety, in this case IgG which recognizes the AM Fc receptor, covalently-linked to a DNA-binding moiety, such as a cationic polyamine. A Complex was formed between immunoglobulin G-polylysine conjugate (IgG-pL) and plasmid DNA carrying the LacZ reporter gene (pSV beta). The conjugate-DNA complex was added directly to the AMs in culture and incubated for 24 h, after which LacZ gene expression was analyzed for beta-galactosidase activity by microfluorometry using a fluorogenic beta-galactosidase substrate, 5-dodecanoylaminofluorescein di-beta-D-galactopyranoside (C12FDG). The AMs treated with the IgG-pL/DNA complex exhibited galactosidase activity significantly augmented over background levels. Effective gene transfer was shown to require both the DNA-binding moiety and cognate moiety for the cell surface receptor. Specific internalization of the complex by the Fc receptor pathway was verified by competitive inhibition using excess IgG. Under this condition, LacZ gene expression was inhibited, suggesting complex internalization through the Fc mediated endocytosis pathway. The requirement of Fc receptors for complex internalization was further demonstrated using cells that lack Fc receptors, e.g., alveolar epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Propofol modulates activation and desensitization of GABAA receptors in cultured murine hippocampal neurons

Propofol (2,6 di-isopropylphenol) is an alkyphenol recently introduced for use as a general anesthetic. The modulation of GABAA receptor activation and desensitization by propofol was studied using a rapid perfusion system and whole-cell voltage-clamp recordings from mouse hippocampal neurons. The effects of concentrations of propofol used clinically on single-channel and synaptic currents were also examined. Propofol evoked current responses (EC50 = 61 microM) and shifted the dose-response curve of GABA-activated current to the left without altering the maximum of the GABA response. Preincubation with propofol and GABA led to desensitization of the GABA response (EC50 = 454 microM and 23 microM, respectively). Saturating concentrations of GABA (600 microM) evoked currents that peaked and then declined in a biexponential fashion with fast and slow time constants of tau f = 1.0 sec and tau s = 3.5 sec. Propofol (10 microM) did not change the amplitude of the peak response but decreased the rates of decay approximately 1.5-fold and enhanced the steady-state current proportionately. Recovery from desensitization was also biexponential (tau f = 11 sec, tau s = 69 sec) but not influenced by propofol. Single-channel recordings from outside-out patches demonstrated that both propofol and GABA activated channels with a 30 pS and 21 pS open state. Propofol increased the frequency but not the duration or conductance of GABA-activated events. Miniature inhibitory postsynaptic currents (mlPSCs) were evoked by the application of hypertonic sucrose to the cell soma. Propofol (2 microM) prolonged the decay time of mlPSCs to an extent similar to which it increased the open probability of GABA-activated channels (2.3- vs 3-fold). A sequential model, based on a previous scheme of GABA receptor gating (Weiss and Magelby, 1989), is presented to summarize propofol's actions on GABAA receptor function. We show through simulation that the model reliably reproduced the whole-cell tracings. Our results indicate that propofol's neurodepressive actions will be associated with enhancement of inhibitory synaptic transmission.

Receptor-mediated peptide delivery in pulmonary epithelial monolayers

The present study investigated the feasibility of utilizing receptor-mediated endocytosis as a means to enhance peptide delivery to the pulmonary epithelium. The strategy employs a molecular conjugate consisting of a cognate moiety, transferrin (TF), covalently-linked to a model polypeptide, horseradish peroxidase (HRP), via a reversible disulfide linkage. A cultured alveolar epithelial monolayer system was used to simulate the conditions of the pulmonary epithelium and to allow accurate quantitation of intra- and transcellular peroxidase transport. The alveolar cells were isolated from rat lungs by enzymatic digestion and grown on microporous tissue culture-treated polycarbonate filters. A significant increase in the uptake of HRP by the cell monolayer was observed upon its conjugation with TF. The effect was found to be concentration-dependent, being more pronounced at low concentrations, i.e., 3.9- and 1.2-fold increase over unconjugated HRP controls at the concentration levels of 0.05 and 1.50 U/ml respectively. Effective peroxidase uptake was shown to require the TF cognate moiety for the cell surface receptor. Specific internalization of the conjugate by the TF endocytic pathway was verified by competition for the TF receptor. Conjugate internalization was not followed by a proportional increase in transcytosis, i.e., at 0.05 U/ml conjugate level, a 1.7-fold increase in transcytosis was observed as compared to 3.9-fold for endocytosis. Effective enhancement of transcytosis was achieved by treating the monolayers with brefeldin A (BFA), a compound known to affect intracellular transport of TF receptor complexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Curvilinear relations between age and hemostatic parameters in Chinese

The role of hemostatic factors in the pathogenesis of cardiovascular disease has gained much attention recently. Information about hemostatic factors, and their age patterns is sparse for orientals. With the data collected in the Cardiovascular Disease Risk Factor Two-township Study in Taiwan, this study shows that, in general, the older the age, the stronger the tendency toward thrombosis. With advancing age, prothrombin time, activated partial thromboplastin time, and antithrombin-III level decreased steadily; but mean values of fibrinogen, factor VIIc, and factor VIIIc increased. Gender differences in the age patterns of the above factors are carefully described. Curvilinear relations between hemostatic factors and age were demonstrated for adults aged 18 and above for all hemostatic factors studied. This curvilinearity should be taken into consideration when adjusting for the effect of age in data analysis to avoid residual confounding, particularly when the age range of the study subjects is wide.

Paraumbilical vein tumor thrombosis in hepatocellular carcinoma

To evaluate the incidence and role of paraumbilical vein tumor thrombosis (PUVT) in hepatocellular carcinoma, we studied 431 patients with hepatocellular carcinoma. Nine patients (2.1%), all male, presented with PUVT. Eight of those patients were positive for hepatitis B surface antigen, with the size of the main tumor being at least 9 cm. All nine patients had a combination of left lobe invasion and left portal vein thrombosis. The dilated paraumbilical vein was not present before the PUVT occurred. The survival time for these nine patients was from 3 to 180 days (median 25 days). The poor prognosis of patients with PUVT resulted from the advanced stage of hepatocellular carcinoma and already poor general physical condition of these patients, but was not a result of the PUVT itself. We present a possible sequence of formation of PUVT.