Tid1, a cochaperone of the heat shock 70 protein and the mammalian counterpart of the Drosophila tumor suppressor l(2)tid, is critical for early embryonic development and cell survival

Tid1 is the mammalian counterpart of the Drosophila tumor suppressor Tid56 and is also a DnaJ protein containing a conserved J domain through which it interacts with the heat shock protein 70 (Hsp70) family of chaperone proteins. We generated a Tid1 conditional mutation in mice, and the subsequent global removal of the Tid1 protein was achieved by crossing these conditional knockout mice with general deletor mice. No Tid1(-/-) embryos were detected as early as embryonic day 7.5 (E7.5). Nonetheless, Tid1-deficient blastocysts were viable, hatched, formed an inner cell mass and trophectoderm, and implanted (E4.5), suggesting that the homozygous mutant embryos die between E4.5 and E7.5. To assess the function of Tid1 in embryonic cells, mouse embryonic fibroblasts with the homologous Tid1 floxed allele were produced. Tid1 removal in these cells led to massive cell death. The death of Tid1-deficient cells could be rescued by ectopic expression of wild-type Tid1 but not by expression of the Tid1 protein that had a mutated J domain and was thus incapable of binding to Hsp70. We propose that Tid1 is critical for early mammalian development, most likely for its function in sustaining embryonic-cell survival, which requires its association with Hsp70.

Hepatitis C virus infection among teenagers in an endemic township in Taiwan: epidemiological and clinical follow-up studies

The aim of the study was to elucidate the epidemiological features of Hepatitis C virus (HCV) infection among teenagers in an endemic area by conducting a mass screening study. We also investigated the clinical outcome of the anti-HCV-positive subjects by conducting subsequent short-term and long-term follow-up studies. All 2837 students of two junior middle schools in Tzukuan, aged 13-16 years, were invited to be screened for anti-HCV, HBsAg, AST and ALT in October 1995. A total of 2726 (96%) students responded. Anti-HCV, HCV RNA and aminotransferase levels were evaluated among anti-HCV-positive students 1 month and 30 months later, respectively. A total of 38 (1.4%; M/F = 22/16) participants were anti-HCV-positive. The anti-HCV-positive students had higher rates of exposures to transfusion, anti-HCV-positive families and surgery. The prevalence (2.8%) of the 7 maritime villages was markedly higher than that (0.7%) of the other 8 villages (P < 0.001). Subsequent follow-up studies demonstrated that there might be 5 cases of acute or recent HCV infection, and 6 cases who had recovered from chronic HCV infection.

Significance of portal hemodynamic investigation in prediction of hepatic functional reserve in patients with hepatocellular carcinoma undergoing operative treatment

BACKGROUND/AIMS

To evaluate clinical significance of portal hemodynamic investigation in prediction of hepatic functional reserve in patients with hepatocellular carcinoma undergoing operative treatment.

METHODOLOGY

By using the color Doppler velocity profile technique, preoperative portal hemodynamic status was assessed in 29 patients with hepatocellular carcinoma treated surgically, including 15 segmentectomies, 6 hemihepatectomies and 8 transarterial chemoembolizations. Forty-six normal volunteers were taken as control. Comparison of preoperative portal hemodynamics between patients recovering from operation smoothly (tolerant subgroup) and those with major complications or death (intolerant subgroup) was done, and discriminant analysis was employed to identify the cut-off value for significant parameters that maximally separate the tolerant subgroup from the intolerant subgroup.

RESULTS

In the portal trunk, CSVmax (maximum cross-sectional mean velocity) was significantly lower in the hepatocellular carcinoma group compared with the normal group (P < 0.01); flow volume was not obviously different between the two groups; congestion index was markedly higher in the hepatocellular carcinoma group than that of the normal group (P < 0.05). In the splenic vein, CSVmax and congestion index was not obviously different between the hepatocellular carcinoma and the normal groups; flow volume was significantly higher in the hepatocellular carcinoma group than that of the normal group (P < 0.05). In the hepatocellular carcinomas, twenty-three patients recovered smoothly from the operation and the remaining 6 had severe complications or death. Tolerant subgroup had a significantly higher preoperative CSVmax and flow volume and lower congestion index of the portal trunk compared with the intolerant subgroup (all P < 0.01). Discriminant analysis revealed that portal trunk CSVmax > 13.50 cm/s and flow volume > 12.13 mL/min/kg could predict tolerance for surgery, with an accuracy of 82.7% and 89.7%, respectively.

CONCLUSIONS

The results suggest that preoperative portal hemodynamic status in hepatocellular carcinomas had a close correlation with hepatic functional reserve, and CSVmax and flow volume of portal trunk might become valuable predictive parameters.

Changing prevalence of hepatitis C virus genotypes: molecular epidemiology and clinical implications in the hepatitis C virus hyperendemic areas and a tertiary referral center in Taiwan

To determine the hepatitis C virus (HCV) genotype distribution in Taiwan and to clarify the relationship between genotype and the pathogenesis of HCV infection, 1,164 subjects positive for serum HCV antibodies and HCV RNA from three HCV hyperendemic areas (Masago, Tzukuan, and Taoyuan) and a tertiary referral center in Taiwan were studied during 1995-1997. HCV genotypes and viral loads were determined using Okamoto's method and branched DNA assay, respectively. Genotype 1b was the most prevalent in Tzukuan (61.9%), Taoyuan (76.9%), and the referral center (47.0%). By contrast, genotype 2a was the major HCV type in Masago (63.5%). Prevalence of genotype 1b positively and that of genotype 2a negatively correlated to age, regardless of study populations (P < 0.01). Based on multivariate analysis, the significant factors associated with the presence of cirrhosis, with or without hepatocellular carcinoma, in chronic hepatitis C patients were genotype 1b and age. In conclusion, these results underline that independent HCV outbreaks continue in HCV hyperendemic areas in Taiwan, concomitant with a changing relative prevalence of HCV genotypes in relation to age. Both the correlation of genotype 1b with age (cohort effect) and intrinsic properties of HCV genotypes are probably responsible for the association between genotype and the pathogenesis of HCV infection.

Hepatocellular carcinoma: US-guided percutaneous microwave coagulation therapy

PURPOSE

To evaluate the use of percutaneous microwave coagulation therapy for hepatocellular carcinoma, particularly with tumor nodules larger than 2 cm in diameter.

MATERIALS AND METHODS

Fifty patients with 107 hepatocellular carcinoma nodules (mean diameter, 2.7 cm +/- 1.5 [SD]; range, 0.8-6.4 cm) were treated with percutaneous microwave coagulation therapy. Single electrode insertion was used in 46 nodules (43.0%) 2 cm or smaller, whereas multiple electrode insertion was applied in 61 (57.0%) nodules larger than 2 cm.

RESULTS

At 1 month after therapy, technical success for tumors 2 cm or smaller and those larger than 2 cm was achieved in 45 (98%) and 56 (92%) nodules, respectively. After follow-up of 9 months or longer, local recurrence was found in one nodule (2%) sized 1.8 cm and in five nodules (8%) larger than 2 cm. At the end of the study, 26 (52%) of 50 patients were free of disease, and disease-free survival rates at 1 and 2 years were 55% and 41%, respectively. Overall survival rates at 1, 2, and 3 years were 96%, 83%, and 73%, respectively.

CONCLUSION

Percutaneous microwave coagulation therapy is an effective and safe therapeutic modality for hepatocellular carcinoma. A multiple electrode insertion technique can enhance the effectiveness of this therapy in tumors 6 cm or smaller.

Intraoperative liver ultrasound: the Chinese experience

This article introduces the experience in intraoperative liver ultrasound in China. Intraoperative liver ultrasound was mainly used in patients treated for hepatocellular carcinoma (HCC) and hepatolithiasis, with purposes for further diagnosis and decision making and guidance of surgical procedures. With respect to detection of liver tumors, intraoperative ultrasound (IOUS) was significantly more sensitive, especially in small foci, as compared with preoperative ultrasound and computed tomography scanning, as well as intraoperative inspection and palpation. It was also more precise in localizing lesions than preoperative imaging investigations. Intraoperative echoangiography via hepatic arterial injection of carbon dioxide was shown not only to help assess position of catheter and vascularity of tumors but also to improve sensitivity in detecting small tumor foci in patients undergoing hepatic arterial chemoembolization. Intraoperative ultrasound was also used to guide hepatectomies. It ensured to obtain curative resection of the tumors and maximum preservation of functioning hepatic parenchyma simultaneously. For hepatolithiasis, IOUS offered accurate localization of stones, lithotomy (with its guidance), reduction of the rate of residual stones, and follow-up of the outcome of lithotomy.

Color Doppler velocity profile assessment of portal hemodynamics in cirrhotic patients with portal hypertension: correlation with esophageal variceal bleeding

PURPOSE

Using the color Doppler velocity profile (CDVP), we investigated portal hemodynamics and their relationship with esophageal variceal bleeding (EVB) in patients with cirrhosis and portal hypertension.

METHODS

The hemodynamics of the portal trunk, right anterior portal branch, and splenic vein were evaluated in 69 cirrhotic patients with portal hypertension and 46 healthy volunteers. The CDVP, a recently developed Doppler software, was used to measure blood flow velocity and flow volume; evaluate the spatial distribution of flow velocities in the cross-section of a vessel (velocity profile), as reflected by the profile parameter (n); and assess changes in flow volume over time (flow profile). The congestion index was calculated by dividing the cross-sectional area by the maximum cross-sectional velocity (CSVmax). The hemodynamic features were compared between patients without a history of EVB [EVB(-)] and those with a history of EVB [EVB(+)], and a logistic regression model was employed to identify factors associated with EVB.

RESULTS

Compared with the healthy group, the cirrhotic group had a significantly lower mean CSVmax in the portal trunk and right anterior portal branch (both p < 0.01), a significantly elevated mean flow volume in the splenic vein and portal trunk (both p < 0.01), a significantly elevated mean ratio of splenic vein flow volume to portal trunk flow volume (SV/PT) (p < 0.001), and a significantly greater mean congestion index in the portal trunk, right anterior portal branch, and splenic vein (all p < 0.01). In the cirrhotic group, there was a significantly higher incidence of a flat flow pattern in the right anterior portal branch and a phasic flow pattern in the splenic vein than in the healthy group (both p < 0.01). Among cirrhotic patients, the EVB(+) group had a significantly greater mean flow volume in the splenic vein (p < 0.01), greater mean SV/PT (p < 0.01), greater mean spleen size (p < 0.05), and lower mean portal trunk n value (p < 0.05) compared with the EVB(-) group. Logistic regression analysis revealed that the SV/PT and portal trunk n value were independent EVB-related factors.

CONCLUSIONS

The results suggest that portal hemodynamics in cirrhotic patients are characterized by passive congestion and increased blood flow. However, these 2 features had different preponderances in different parts of the portal venous system. Increased flow in the splenic vein may be the primary source of increased portal flow and may play a role in the development of EVB. The SV/PT and portal trunk n value may be valuable factors for predicting EVB.

The serological and molecular epidemiology of GB virus C/hepatitis G virus infection in a hepatitis C and B endemic area

OBJECTIVES

To investigate the serological and molecular characteristics of GB virus C/hepatitis G virus (GBV-C/HGV) infection in the hepatitis C virus (HCV)/hepatitis B virus (HBV)-endemic areas in Taiwan.

METHODS

Sera from 200 residents from Masago, an HCV/HBV-endemic community in Taiwan, and 400 blood donors were tested for GBV-C/HGV RNA by using nested reverse transcription-polymerase chain reaction and for antibodies to GBV-C/HGV E2-protein (anti-E2) by an enzyme-linked immunosorbent assay. Phylogenetic analysis of GBV-C/HGV was performed.

RESULTS

The prevalence of GBV-C/HGV viraemia, anti-E2 and GBV-C/HGV exposure among residents of Masago was significantly higher than that among donors (17.0%, 25.5% and 39.5% vs. 3.3%, 7.5% and 10.3%, respectively; all P < 0.0001). In Masago, the prevalence of GBV-C/HGV exposure was significantly higher in residents exposed to HCV than in those without HCV exposure (45.8% vs. 24.1%;P< 0.005). Based on multivariate analyses, HCV viraemia was the only significant factor associated with elevated levels of alanine aminotransferase in Masago. Phylogenetic analysis showed all 34 GBV-C/HGV isolates from Masago clustered within genotype 3.

CONCLUSIONS

GBV-C/HGV was highly prevalent in Masago, an HCV/HBV-endemic community in Taiwan. HCV viraemia played the most important clinical hepatopathic role in the area. Infections with other hepatitis viruses did not influence the anti-E2 seroconversion from GBV-C/HGV infections.

The epidemiology of TT virus (TTV) infection in a hepatitis C and B virus hyperendemic area of southern Taiwan

TT virus (TTV) is a newly isolated DNA virus from the serum of a patient with posttransfusion hepatitis of unknown etiology in 1997. To evaluate the clinical and molecular characteristics of TT virus (TTV) in a hepatitis C virus (HCV) and B (HBV) hyperendemic area (Masago), 200 residents were enrolled in the study. The sera were tested for alanine aminotransferase (ALT), HCV RNA and GB virus C/Hepatitis G virus (HGV) RNA, TTV DNA, HBsAg, anti-HCV and antibodies to HGV E2-protein (anti-E2). TTV DNA was positive in 99 of the 200 sera with a prevalence rate of 49.5%. The prevalence of HBsAg, anti-HCV, HCV RNA, HGV RNA, anti-E2 and HGV exposure (defined as positive for serum HGV RNA and/or anti-E2) was 38.9%, 69.5%, 64.5%, 17.0%, 25.5% and 39.5%, respectively. Neither clinical nor virological factors were associated with TTV viremia. The rate of ALT abnormality was significantly elevated in HCV RNA-positive (34.9%) than -negative (7.0%) residents (p < 0.001). HCV viremia was the only factor significantly associated with ALT elevation by multiple logistic regression (odds ratio: 6.96; 95% C.I.: 2.60-18.7). We concluded that in this HCV/HBV hyperendemic area, the prevalence of TTV DNA was high. No significant clinical factor was observed to be associated with TTV infection. TTV infection is not related to abnormal ALT levels and ALT abnormality was mainly attributable to HCV but not TTV, HBV or HGV infection.

[Anatomical study and clinical applications of flaps based on cutaneous branches arising from posterior tibial vessels]

OBJECTIVE

To provide an anatomical basis for the clinical applications of the medial fascinocutaneous flap of calf and to verify its clinical value.

METHODS

In 20 lower limb specimens of adult human cadavers, the number, course, size, position and distribution of septocutaneous branches of the posterior tibial vessels are marked by means of red latex and black ink irrigations through femur artery and septocutaneous branches of the posterior tibial artery respectively.

RESULTS

The posterior tibial artery gives off several septocutaneous branches at the upper, middle and lower one-third of the leg respectively. Each septocutaneous artery has one or sometimes two concomitant veins. Based on this result, anterograde or reverse pedicled fasciocutaneous flap can be performed for the purpose of repairing soft tissue defects of leg and foot. The flap was clinically applied to treat leg and foot soft tissue defects in 12 cases with satisfactory results.

CONCLUSION

The flap is easy to dissect, the posterior tibial artery can be preserved with high successful rate. Therefore, it offers an useful alternative in the repairing and reconstruction of nonextensive soft tissue defects in the leg and foot.

[Influence of lead on activity of nitric oxide synthase in neurons and vessel smooth muscle of small intestine in rats]

The beta-NADPH histochemical method was used to study the effect of lead on activity of nitric oxide synthase(NOS) in neurons and vessel smooth muscles of intestinal wall in rats. The results showed that the number of NOS positive neurons and fibers was decreased and degenerative changes of some NOS positive neurons were found after the lead acetate intraperitoneal injection. The activity of NOS in the vessel smooth muscles was reduced. It suggests that lead colic may be induced by reduction of NO in the neurons which innervate the gut smooth muscles.

Intramolecular activation of a Ca(2+)-dependent protein kinase is disrupted by insertions in the tether that connects the calmodulin-like domain to the kinase

Ca(2+)-dependent protein kinases (CDPK) have a calmodulin-like domain (CaM-LD) tethered to the C-terminal end of the kinase. Activation is proposed to involve intramolecular binding of the CaM-LD to a junction sequence that connects the CaM-LD to the kinase domain. Consistent with this model, a truncated CDPK (DeltaNC) in which the CaM-LD has been deleted can be activated in a bimolecular interaction with an isolated CaM-LD or calmodulin, similar to the activation of a calmodulin-dependent protein kinase (CaMK) by calmodulin. Here we provide genetic evidence that this bimolecular activation requires a nine-residue binding segment from F436 to I444 (numbers correspond to CPK-1 accession number L14771). Two mutations at either end of this core segment (F436/A and VI444/AA) severely disrupted bimolecular activation, whereas flanking mutations had only minor effects. Intramolecular activation of a full-length kinase was also disrupted by a VI444/AA mutation, but surprisingly not by a F436/A mutation (at the N-terminal end of the binding site). Interestingly, intramolecular but not bimolecular activation was disrupted by insertion mutations placed immediately downstream of I444. To show that mutant enzymes were not misfolded, latent kinase activity was stimulated through binding of an antijunction antibody. Results here support a model of intramolecular activation in which the tether (A445 to G455) that connects the CaM-LD to the kinase provides an important structural constraint and is not just a simple flexible connection.

T cells can use either T cell receptor or CD28 receptors to absorb and internalize cell surface molecules derived from antigen-presenting cells

At the site of contact between T cells and antigen-presenting cells (APCs), T cell receptor (TCR)-peptide-major histocompatibility complex (MHC) interaction is intensified by interactions between other molecules, notably by CD28 and lymphocyte function-associated antigen 1 (LFA-1) on T cells interacting with B7 (B7-1 and B7-2), and intracellular adhesion molecule 1 (ICAM-1), respectively, on APCs. Here, we show that during T cell-APC interaction, T cells rapidly absorb various molecules from APCs onto the cell membrane and then internalize these molecules. This process is dictated by at least two receptors on T cells, namely CD28 and TCR molecules. The biological significance of T cell uptake of molecules from APCs is unclear. One possibility is that this process may allow activated T cells to move freely from one APC to another and eventually gain entry into the circulation.

TCR-Mediated internalization of peptide-MHC complexes acquired by T cells

Peptide-major histocompatibility complex protein complexes (pMHCs) on antigen-presenting cells (APCs) are central to T cell activation. Within minutes of peptide-specific T cells interacting with APCs, pMHCs on APCs formed clusters at the site of T cell contact. Thereafter, these clusters were acquired by T cells and internalized through T cell receptor-mediated endocytosis. During this process, T cells became sensitive to peptide-specific lysis by neighboring T cells (fratricide). This form of immunoregulation could explain the "exhaustion" of T cell responses that is induced by high viral loads and may serve to down-regulate immune responses.

Methylation and gene mutation in eukaryotic DNA

5-methylcytosine (m5C) as a rare base exists in eukaryotic genomes, which is a normal constitution in many eukaryotic DNA and the existence of m5C is a feature of eukaryotic DNA. Under regular physiological conditions, cytosine of eukaryotic DNA is usually methylated. Up to the present, many people consider that the m5C may be mutation hotspots by the deamination leading to gene mutation. Our study indicated that the spontaneous mutation caused by the transition of G.C --> A.T, in eukaryotic DNA, may result from the tautomer changing of base pairs and may also be cause by other factor actions, however it could not be caused by the deamination of m5C.

Diagnosis of hepatocellular carcinoma by quantitative detection of hepatoma-specific bands of serum gamma-glutamyltransferase

Tissues of hepatocellular carcinoma (HCC) can express hepatoma-specific gamma-glutamyltransferase (GGT) and secrete GGT into circulating blood. Serum GGT was separated into several bands (up to 11), including hepatoma-specific bands (HSBs, I', II, and II') by a vertical slab electrophoresis assay of polyacrylamide stage gradient gel. In the present study, the HSBs of serum GGT were separated, and the HSB activity was quantitatively measured in 91 patients with HCC and compared with that of 106 patients with benign liver disease, 16 patients with extrahepatic tumors, and 30 healthy control subjects. Significant differences of the HSB activity were observed between the HCC group and each study group. An HSB activity greater than 5.5 U/L seems to be diagnostic of HCC. The quantitative method has a sensitivity of 85.3%, a specificity of 97.2%, a positive predictive value of 95.1%, a negative predictive value of 91.2%, and an accuracy of 92.5% for detecting HCC. No correlation was found between HSB activity and the serum alpha-fetoprotein (AFP) level or tumor size in patients with HCC. The quantitative analysis of HSB activity of GGT is superior to detection of the AFP concentration and is useful in early diagnosis of small HCC or AFP-negative HCC.

Protein three-dimensional structural databases: domains, structurally aligned homologues and superfamilies

This paper reports the availability of a database of protein structural domains (DDBASE), an alignment database of homologous proteins (HOMSTRAD) and a database of structurally aligned superfamilies (CAMPASS) on the World Wide Web (WWW). DDBASE contains information on the organization of structural domains and their boundaries; it includes only one representative domain from each of the homologous families. This database has been derived by identifying the presence of structural domains in proteins on the basis of inter-secondary structural distances using the program DIAL [Sowdhamini & Blundell (1995), Protein Sci. 4, 506-520]. The alignment of proteins in superfamilies has been performed on the basis of the structural features and relationships of individual residues using the program COMPARER [Sali & Blundell (1990), J. Mol. Biol. 212, 403-428]. The alignment databases contain information on the conserved structural features in homologous proteins and those belonging to superfamilies. Available data include the sequence alignments in structure-annotated formats and the provision for viewing superposed structures of proteins using a graphical interface. Such information, which is freely accessible on the WWW, should be of value to crystallographers in the comparison of newly determined protein structures with previously identified protein domains or existing families.

Dimethylformamide-induced occupational liver injury--a case report

Dimethylformamide(DMF), a widely used industrial solvent, has been reported to induce subtle to clinically overt hepatotoxicity. Liver injury due to occupational exposure through inhalation and skin contact have been sporadically reported. We reported a 42-year-old male Taiwanese who developed progressive, intermittent abdominal pain for 6 months after working in a synthetic leather factory. Acute hepatitis episode occurred after working in an enclosed and poorly-ventilated workplace for one day. Based on occupational history, pathological examination and serial liver function examinations, the case was compatible with DMF-induced acute chemical hepatitis.

[Interleukin-6 production by human gingival fibroblasts following stimulation with Actinobacillus actinomycetemcomitans]

Actinobacillus actinomycetemcomitans(Aa), elaborating a multiplicity of virulence factor and tissue-damaging products, is considered an etiological agent in periodontal disease. Serotype b is the most frequently isolated serotype in localized juvenile periodontitis patients, suggesting a particularly high periodontopathic potential for serotype b strains. Interleukin-6(IL-6) plays an important role in the mediation of inflammatory and immune responses as well as in the osteoclastic bone resorption. However, there is little information regarding the effect of the different serotypes of Aa on IL-6 production by human gingival fibroblasts (HGF). Therefore, the purpose of this study was to compare the ability of the three serotypes (a, b, and c) of Aa sonicates to induce the production of IL-6 by HGF. In fibroblast cultures, confluent monolayers of HGF were incubated with sonic extracts of Aa-511 (serotype a), Aa-Y4 (serotype b), and Aa-652 (serotype c) at various concentrations for 48 h at 37 degrees C in 5% CO2 and air. At the end of the culture period, supernatants were collected and analysed for IL-6 content by using EIA and bioassay. In order to compare the effects of non-lipopolysaccharide (LPS) activation of Aa sonicates on IL-6 production by HGF, we added polymyxin B in cultures with Aa sonicates to bind LPS. The results were summarized as follows. (1) All three serotypes of Aa sonicates had similar dose-dependent stimulant effects on IL-6 production by HGF, and the biological activities of IL-6 correlated with their immunoreactivities. (2) The maximum releases of IL-6 by HGF were achieved at concentrations of 10 to 100 micrograms protein/mL of Aa sonicates, and the ability of Aa-Y4 to induce the release of IL-6 was higher than that of Aa-511 and Aa-652 at these concentrations. (3) Polymyxin B (50 micrograms/mL) effectively decreased the amounts of IL-6 produced by stimulation of the HGF with 10 micrograms protein/mL of Aa sonicates. However, the polymyxin B-treated Aa-Y4 sonicate showed a higher ability to induce the release of IL-6 than the other two strains. These results indicate that Aa-Y4 (serotype b) has a higher potency to induce HGF secretion of IL-6; thus contributing to a comparatively stronger efficacy to the destruction of periodontal tissue in periodontitis.