[A study of the clinical curative effect of nucleos(t)ide analogues treated to pegylated interferon-α add-on therapy in patients with chronic hepatitis B]

Objective: To investigate the hepatitis B surface antigen (HBsAg) clearance condition and its predictive factors after treatment with nucleos(t)ide analogues to pegylated interferon-α add-on therapy in patients with chronic hepatitis B. Methods: Patients with chronic hepatitis B who visited the First Affiliated Hospital of Zhengzhou University from 2018~2019 were prospectively enrolled. HBsAg≤ 1500 IU/mL, hepatitis B e antigen-negative, HBV DNA undetectable, received antiviral treatment with nucleos(t)ide analogues for at least one year, and pegylated interferon-α add-on therapy for 48 weeks were included. The primary endpoint of study was to determine the proportion of HBsAg clearance at 72 weeks. Concurrently, the predictive factors for HBsAg clearance were analyzed. Quantitative and qualitative data were analyzed using a t-test or non-parametric test and a Fisher's exact test. Results: A total of 38 cases were included in this study, of which 13 cases obtained HBsAg clearance at 48 weeks of therapy and another six cases obtained HBsAg clearance throughout the extended treatment period of 72 weeks, accounting for 50.00% of all enrolled patients. There was a significant difference in HBsAg dynamics between the HBsAg clearance group and the non-clearance group (P < 0.05). Univariate logistic regression analysis showed that patients' age, baseline, 12-and 24-week HBsAg levels, and early HBsAg reduction were predictive factors for HBsAg clearance at 72 weeks of treatment. Multivariate logistic regression analysis showed that age (OR = 1.311; P = 0.016; 95% confidence interval: 1.051~1.635) and HBsAg levels at 24 weeks of treatment (OR = 4.481; P = 0.004; 95% confidence interval: 1.634~12.290) were independent predictors for HBsAg clearance. Conclusion: Hepatitis B e antigen-negative, nucleos(t)ide analogue treated, HBsAg ≤ 1500 IU/mL, and HBV DNA undetectable, peg-IFNα add-on treatment for 48 weeks could promote HBsAg clearance in patients with chronic hepatitis B. Six of the sixteen cases (37.50%) who did not obtain HBsAg clearance at week 48 did so with the course of therapy extended to week 72. Hence, the optimal individualized treatment strategy should be customized according to the predictors rather than the fixed 48-week course. Age (≤ 38), baseline HBsAg level (≤2.86 log(10)IU/ml), HBsAg level at 24 weeks (≤ 0.92 log(10)IU/ml), and 12-week HBsAg decrease from baseline (≥ 0.67 log(10)IU/ml) indicate that patients are highly likely to obtain HBsAg clearance at the 72 weeks of combination therapy, in which the combined indicator based on HBsAg level ≤0.92 log(10)IU/ml at 24 weeks will identify 85.0% to 100.0% of patients with HBsAg clearance.

[Association between HBV viral load and severity of liver inflammation in patients with chronic hepatitis B virus infection]

Objective: To explore the relationship and dynamic changes between virological markers and hepatic pathological damage due to host anti-hepatitis B virus (HBV) immunity in the natural course of disease in chronic HBV infected patients. Methods: Two hundred and thirty-eight adult chronic HBV-infected patients who underwent liver biopsy from January 2016 to June 2022 in Taizhou Hospital, Zhejiang Province, were retrospectively selected. General clinical data such as age, gender, platelets, ALT, AST, albumin, HBV DNA, qHBsAg, HBeAg, and liver pathology diagnostic indexes such as the grade of liver necroinflammation and liver fibrotic stages of the patients were collected. The patients were grouped according to HBeAg status, and subgrouped according to different grades of liver necroinflammation and different HBV DNA loads. Statistical analyses were performed to compare the differences in HBV virologic marker levels between the groups, and the correlation between them and the indicators of hepatic inflammatory injury, such as ALT,AST, and the grade of liver necroinflammation in the patients. Results: The levels of HBV virological markers in HBeAg-positive patients with moderate or higher liver necroinflammatory grade (G≥2) were significantly lower than those with mild (no) liver necroinflammatory grade (G < 2) (P < 0.01); whereas the opposite trend was observed in HBeAg-negative patients, with the levels of HBV DNA, and qHBsAg in the G≥2 subgroup being significantly higher than those in the G < 2 subgroup (P < 0.01). Correspondingly, HBV DNA level and qHBsAg showed weak to moderately strong negative correlation with liver necroinflammatory grade and AST which was an indicator of hepatic inflammatory injury in HBeAg-positive patients (P < 0.05); whereas in HBeAg-negative patients, they showed weak to moderately strong positive correlation with hepatic inflammatory activity and ALT, AST (P < 0.001), in which qHBsAg showed only a weak positive correlation with patients' liver necroinflammatory grade (P = 0.003). Further subgroup analyses of HBeAg-positive patients according to whether the HBV DNA level was > 2×10(6) IU/ml showed weak to moderate negative correlations between HBV virological markers and liver necroinflammatory grade as well as ALT and AST in the subgroup of patients with HBV DNA > 2×10(6) IU/ml (P < 0.05); however, the negative correlation disappeared in patients who were still HBeAg positive and had HBV DNA ≤ 2×10(6) IU/ml. Moreover, HBV DNA and ALT, HBeAg and AST showed moderate positive correlation (P < 0.05). Conclusion: We speculate that the activation of host anti-HBV immunity can efficiently inhibit HBV replication by targeting the infected hepatocytes, but only in the early phase of disease progression in HBeAg positive patients with HBV DNA high (> 2×10(6) IU/ml).

[A preliminary discussion on carnosine dipeptidase 1 as a potential novel biomarker for the diagnostic and prognostic evaluation of hepatocellular carcinoma]

Objective: To explore carnosine dipeptidase 1 (CNDP1) potential value as a diagnostic and prognostic evaluator of hepatocellular carcinoma (HCC). Methods: A gene chip and GO analysis were used to screen the candidate marker molecule CNDP1 for HCC diagnosis. 125 cases of HCC cancer tissues, 85 cases of paracancerous tissues, 125 cases of liver cirrhosis tissues, 32 cases of relatively normal liver tissue at the extreme end of hepatic hemangioma, 66 cases from serum samples of HCC, and 82 cases of non-HCC were collected. Real-time fluorescent quantitative PCR, immunohistochemistry, western blot, and enzyme-linked immunosorbent assay were used to detect the differences in mRNA and protein expression levels of CNDP1 in HCC tissue and serum. Receiver operating characteristic (ROC) curves and Kaplan-Meier survival were used to analyze and evaluate the value of CNDP1 in the diagnosis and prognosis of HCC patients. Results: The expression level of CNDP1 was significantly reduced in HCC cancer tissues. The levels of CNDP1 were significantly lower in the cancer tissues and serum of HCC patients than those in liver cirrhosis patients and normal controls. ROC curve analysis showed that the area under the curve of serum CNDP1 in the diagnosis of HCC patients was 0.753 2 (95% CI 0.676-0.830 5), and the sensitivity and specificity were 78.79% and 62.5%, respectively. The combined detection of serum CNDP1 and serum alpha-fetoprotein (AFP) significantly improved the diagnostic accuracy (AUC = 0.820 6, 95% CI 0.753 5-0.887 8). The diagnostic sensitivity and specificity of serum CNDP1 for AFP-negative HCC patients were 73.68% and 68.75% (AUC = 0.793 1, 95% CI 0.708 8-0.877 4), respectively. In addition, the level of serum CNDP1 distinguished small liver cancer (tumor diameter < 3 cm) (AUC = 0.757 1, 95% CI 0.637 4-0.876 8). Kaplan-Meier survival analysis showed that CNDP1 was associated with a poor prognosis in HCC patients. Conclusion: CNDP1 may be a potential biomarker for the diagnostic and prognostic evaluation of HCC, and it has certain complementarity with serum AFP.

[Antisense oligodeoxynucleotides: the certain but limited efficacy and the uncovering mechanisms for the cure of chronic hepatitis B]

Recently, several phase I and phase II clinical trials of antisense oligodeoxynucleotides (ASOs) targeting to the commonly shared conserved sequences of HBV transcripts brought us some promising results. Particularly in the report of phase IIb clinical trial of Bepirovirsen (GSK3228836), approximately 9-10% patients with low baseline serum HBsAg (> 100 IU/ml & < 3 000 IU/ml) achieved functional cure after 24 weeks' of Bepirovirsen treatment. After reviewing the results of other clinical trials, one would be impressed to know that ALG-020572 (Aligos), RO7062931 (Roche) and GSK3389404 (GSK) all failed to sufficiently suppress serum HBsAg expression though the hepatocyte-targeted delivery of these ASOs were enhanced via N-acetyl galactosamine conjugation. Bepirovirsen enabled some patients to achieve sustained disappearance of serum HBsAg. The analysis of its distribution in different tissues of patients after drug administration showed that only a few fractions of ASOs entered liver tissues and far fewer eventually entered hepatocytes. Taking into consideration that only a few hepatocytes could be expected positive for HBsAg staining among these participants with low serum HBsAg level. We suspect that the mechanistic contribution of ASOs declining the serum HBsAg is not only via directly acting on the HBV transcripts in hepatocytes, but also via entering non-parenchymal cells such as Kupffer cells and resulting in stimulation and activation of innate immunity. Eventually the serum HBsAg declines in most participants and even disappears in a small fraction of patients with low baseline HBsAg level, via attack the infected hepatocytes evidenced by the aberrant elevation of ALT. Nevertheless, the functional cure of CHB remains a challenging issue and more efforts are needed.

[Some HBeAg-negative chronic hepatitis B patients treated with nucleos(t)ide analogue can achieve HBsAg loss after drug withdrawal: stop-to-cure may be coming]

Nucleoside/Nucleotide analogues (NAs) are widely used for the antiviral treatment of chronic hepatitis B (CHB), however, it is difficult to achieve serum hepatitis B surface antigen (HBsAg) loss with NAs therapy. In recent years, several prospective trails have reported that HBsAg loss (functional cure or clinical cure) also occurs in a small number of hepatitis B e antigen (HBeAg) negative CHB patients who discontinued long-term treatment with NAs. Accordingly, the "stop-to-cure" strategy is proposed. Although the mechanism has not been fully elucidated, the known factors related to serum HBsAg loss with NAs withdrawal include HBV genotype, duration of NAs treatment, serum HBsAg and HBV RNA levels at end-of-treatment, and ethnic differences. In the review, we discuss the best time to stop NAs therapy, the potential markers for predicting relapse after cessation of NAs and the possible mechanism of "stop-to-cure" in HBeAg-negative CHB patients, and propose some suggestions on the time of retreatment.

[Consideration on the possible etiological mechanisms and countermeasures about severe acute hepatitis of unknown origin in children]

Since April 2022, severe acute hepatitis of unknown origin in children has spread to 35 countries and regions around the world, and more than 1 010 cases have been reported. Since the severe acute hepatitis of unknown origin involves a wide range of areas and has a high rate, it is critical to identify the etiology and establish effective preventive, diagnostic and therapeutic measures as soon as possible. This study discusses the possible mechanisms and countermeasures of the severe acute hepatitis of unknown origin in children. It speculates that the occurrence of the recent severe acute hepatitis might be related to adenovirus, adeno-associated virus infection, and the COVID-19 epidemic, while the difference in HLA polymorphism among different races might be related to the fact that reported cases were more common in Europe and the United States. Based on the currently available evidence, it can be preliminarily judged that the risk of large-scale outbreak of severe acute hepatitis of unknown origin in children would be low in China, but the persistent awareness and vigilance of the etiology is still needed.

[Mechanism and clinical significance of HBV reactivation after anti-HCV therapy]

Direct-acting antivirals (DAAs) can strongly inhibit the replication of hepatitis C virus (HCV) and effectively clear the infection, but it may cause hepatitis B virus (HBV) reactivation, leading to severe liver damage and fulminate hepatitis in patients with HCV/HBV coinfection. In this review, we summarized the different replication process of HCV and HBV in infected hepatocytes and consequent innate immune response, and then discussed the molecular mechanism and clinical significance of HBV reactivation, and put forward the clinical precaution.

[Clinical application of serum Golgi protein 73 in patients with chronic liver diseases]

Golgi protein 73 (GP73) is a transmembrane protein on the Golgi apparatus and can be cut and released into the blood. In recent years, an increasing number of clinical studies have shown that the elevated serum GP73 level is closely related to liver diseases. And thus GP73 is expected to be used as a new serum marker for assessing progress of chronic liver diseases. Herein, the clinical application of serum GP73 in chronic hepatitis, liver fibrosis, liver cirrhosis and hepatocellular carcinoma with different etiologies was reviewed based on available literatures; and a research outlook in this field is made.

[A short half-life of cccDNA offer or ignite hope for hepatitis B cure under nucleos(t)ide analogues treatment]

Covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) is the template for HBV replication. Currently, there is a lack of therapeutic drugs that directly target cccDNA. Therefore, blocking cccDNA supplements as fast as possible and reducing the existing cccDNA is the key to achieving a complete cure of chronic hepatitis B. Previous studies have suggested that cccDNA had a long half-life, but a recent study showed that it only took a few months to update cycle of cccDNA pool, and its number was much less than previously predicted. In the future, with the advent of new antiviral drugs that can completely inhibit HBV replication, it is expected that the cccDNA pool will be completely cleared due to its supplement complete blockade, so as to achieve virological cure of chronic hepatitis B.

[A possible mechanism for low-level viremia occurrence in nucleos(t)ide analog-treated chronic hepatitis B patients]

The first-line nucleos(t)ide analogs (NAs) based antiviral drugs can effectively inhibit HBV replication and slow down the progression of chronic hepatitis B. However, about 20% of patients receiving standard NAs antiviral therapy will still develop low-level viremia (LLV). Therefore, understanding the occurrence mechanism of LLV will help to optimize antiviral treatment regimens and improve the prognosis of patients with chronic hepatitis B. This article systematically summarizes the possible mechanisms of LLV occurrence, and the important factor of NAs failure. Taking into account the unique limitations of NAs competitive inhibition of virus replication, weakening host's immune response is not enough to directly eliminate infected hepatocytes. This makes it difficult to achieve a complete virological response in some patients with the active compensatory proliferation of residual infected hepatocytes and the accompanying effective removal or dilution of covalent, closed, circular DNA (cccDNA) pools. Therefore, it is speculated that activating host immunity can eliminate infected liver cells and may be more conducive to address LLV.

[The mechanisms of the translation of polymerase from HBV pregenomic RNA]

Hepatitis B virus (HBV) is an important pathogen that causes different liver diseases such as viral hepatitis and liver cirrhosis. HBV pregenomic RNA (pgRNA) plays a crucial role in HBV life cycle, which is not only the translation template of core (C) and polymerase (P), but also the template of reverse transcription. The ratio of P protein to core protein is tightly regulated. Since P and core are both translated by pgRNA and the open reading frame (ORF) of P is located downstream of the ORF of core, how to initiate P protein translation is a key scientific question. Previous studies suggest that P can be translated through different mechanisms, such as leaky scanning and reinitiation. In this review, we summarized the proposed mechanisms relevant to the translation of polymerase from HBV pgRNA through literature review and derivation.

[Exploring the mechanism of liver enzyme abnormalities in patients with novel coronavirus-infected pneumonia]

Objective: To explore and analyze the possible mechanism of liver injury in patients with coronavirus disease 2019 (novel coronavirus pneumonia, NCP). Methods: The correlation between ALT, AST and other liver enzyme changes condition and NCP patients' disease status reported in the literature was comprehensively analyzed. ACE2 expression in liver tissue for novel coronavirus was analyzed based on single cell sequencing (GSE115469) data. RNA-Seq method was used to analyze Ace2 expression and transcription factors related to its expression in liver tissues at various time-points after hepatectomy in mouse model of acute liver injury with partial hepatectomy. t-test or Spearman rank correlation analysis was used for statistical analysis. Results: ALT and AST were abnormally elevated in some patients with novel coronavirus infection, and the rate and extent of ALT and AST elevation in severe NCP patients were higher than those in non-severe patients. Liver tissue results of single cell sequencing and immunohistochemistry showed that ACE2 was only expressed in bile duct epithelial cells of normal liver tissues, and very low in hepatocytes. In a mouse model of acute liver injury with partial hepatectomy, Ace2 expression was down-regulated on the first day, but it was elevated up to twice of the normal level on the third day, and returned to normal level on seventh day when the liver recovered and hepatocyte proliferation stopped. Whether this phenomenon suggests that the bile duct epithelial cells with positive expression of Ace2 participate in the process of liver regeneration after partial hepatectomy deserves further study. In RNA-Seq data, 77 transcription factors were positively correlated with the expression of Ace2 (r > 0.2, FDR < 0.05), which were mainly enriched in the development, differentiation, morphogenesis and cell proliferation of glandular epithelial cells. Conclusion: We assumed that in addition to the over activated inflammatory response in patients with NCP, the up-regulation of ACE2 expression in liver tissue caused by compensatory proliferation of hepatocytes derived from bile duct epithelial cells may also be the possible mechanism of liver tissue injury caused by 2019 novel coronavirus infection.

[Mechanism relevant to hepatocellular carcinoma occurrence after negative conversion of viral DNA in treatment of chronic hepatitis B patients with nucleos(t)ide drugs]

Hepatocellular carcinoma (HCC) is a common malignant tumor in China, and most of the patients have a background of chronic HBV infection. Nucleos(t)ide drugs (NAs) are currently recommended by major guidelines as a first-line treatments for chronic hepatitis B. However, it is still clinically possible to observe that some patients who have acquired virological response (HBV DNA below the lower detection limit) after NAS treatment progress to HCC, and its mechanism of development is still unclear. In this review, the mechanism relevant to HCC progression in treatment of chronic hepatitis B patients with NAs is analyzed mainly from the aspects of gene integration and persistent inflammatory injury.

[Re-recognition of occult hepatitis B virus infection]

Hepatitis B virus (HBV) infection remains to be a serious public health problem in China. There used to be a high prevalence of HBV infection in China, which resulted in a large number of HBV susceptible and post-infected population. Single anti-HBc positive usually indicates post HBV infection and its prevalence is particularly high among people over 40 years old, some of whom may be occult hepatitis B virus infection (OBI). The clinical diagnosis of OBI is difficult and easily missed. Since OBI may cause chronic liver disease progression and even lead to cirrhosis and hepatocellular carcinoma eventually, and more importantly, patients with OBI may leed to HBV reactivation when the immune function decreases or immunosuppressive therapy is performed, the accurate identify of OBI is of particular importance. Moreover, OBI is the potential source of HBV infection, which may transmit through blood transfusion, organ transplantation and mother-to-child transmission. In view of this situation, we reviewed the mechanism, prevalence and definition of OBI, and proposed a determination system for replication-competent HBV DNA based on our understanding of the updated OBI definition. It is expected to be beneficial for OBI diagnosis, treatment and management.

[Expression and clinical significance of chemokine CXCL10 and its receptor CXCR3 in hepatocellular carcinoma]

OBJECTIVE

To explore the expression and clinical significance of chemokine CXCL10 and CXCR3 in hepatocellular carcinoma (HCC).

METHODS

The expression and prognostic of CXCL10 and CXCR3 in HCC tumor tissues and non-tumor tissues were analyzed in two different publicly available databases the Cancer Genome Atlas (TCGA) and Liver Cancer Institute (LCI). In addition, quantitative real-time PCR (qPCR) was used to detect the mRNA expression of CXCL10 and CXCR3 in 45 HCC clinical samples with HBV infection background. Pearson correlation and Spearman rank correlation were used to determine the correlation between the expression level of CXCL10 and CXCR3 in tumor and non-tumor tissues.

RESULTS

In TCGA database, the expression of CXCL10 in HCC tumor tissues was significantly higher than that in non-tumor tissues (nonpaired samples: 3.379±2.081 vs. 2.213±2.274, P<0.001; paired samples: 3.159±2.267 vs. 2.213±2.274, P=0.018). Similarly in LCI datebase (7.625±1.683 vs. 7.287±1.328, P=0.009). And higher CXCL10 expression was significantly associated with a better prognosis in the patients with HCC both in TCGA and LCI database (P=0.107, P=0.002). In TCGA database, the expression of CXCR3 in HCC tumor tissues was significantly higher than that in non-tumor tissues (nonpaired samples: -0.906±1.697 vs. -1.978±1.629, P<0.001; paired samples: -1.329±1.732 vs. -1.978±1.629, P=0.037), while lower in LCI database (3.989±0.339 vs. 4.074±0.309, P=0.003). In both databases, higher CXCR3 expression was significantly associated with a better prognosis in the HCC patients (P=0.004, P=0.014). Furthermore, in TCGA database, the expression level of CXCL10 and CXCR3 was positively correlated both in HCC tumor tissues and matched non-tumor tissues (r=0.584, P<0.001; r=0.776, P<0.001). The qPCR assay showed that the expression of CXCL10 in HBV-related HCC tumor tissues was significantly higher than those in normal liver tissues [0.479(0.223, 1.094) vs. 0.131(0.106, 0.159), P=0.010], and the expression in HBV-related non-tumor tissues was also significantly higher than those in normal liver tissues [0.484(0.241, 0.846) vs. 0.131(0.106, 0.159), P<0.001]. The same was true as CXCR3 [0.011(0.006, 0.019) vs. 0.002(0.001, 0.004), P=0.004; 0.016(0.011, 0.021) vs. 0.002(0.001, 0.004), P<0.001]. However there was no significant difference of CXCL10 and CXCR3 between tumor tissues and matched non-tumor tissues (P=1.000, P=0.374).

CONCLUSION

Expression of CXCL10 was up-regulated in HCC tissues, expression of CXCR3 was down-regulated in HBV-related HCC tissues, and the higher expression of both genes was correlated with better overall survival in HCC patients.

[Prognostic significance of albumin/globulin ratio on postoperative survival of patients with hepatocellular carcinoma]

Objective: To investigate the prognostic value of albumin/globulin ratio on postoperative survival outcomes in patients with hepatocellular carcinoma. Methods: Data of 630 patients with HCC, who underwent surgical resection from February 2009 to July 2013, were retrospectively analyzed. Patients were divided into low-value group (A/G < 1.5, defined as L group) and high-value group (A/G≥1.5, defined as H group), and their distribution characteristics were observed with the normal A/G threshold value. Independent risk factors' affecting survival and prognosis was analyzed with univariate and multivariate Cox's regression model. Survival trend of all patients with low-value and high-value groups in A, B and C of Barcelona stage (BCLC stage) were analyzed using the Kaplan-Meier method. Results: Multivariate analysis showed that preoperative A/G ratio (P = 0.007), alpha-fetoprotein (P < 0.001), gamma-glutamyltransferase (P = 0.006), RBC (P = 0.014), international normalized ratio (P = 0.009), preoperative BCLC staging (P < 0.001) and number of tumors (P = 0.003), and intraoperative blood transfusion (P < 0.001) were independent prognostic factors affecting long-term survival in HCC patients. The median overall survival time in-group L was 15 months, significantly lower than that in group H of 42 months (P < 0.001). Stratified analysis showed that the short-term survival advantage of patients with high A / G value was limited to those with Barcelona stage A (P < 0.001), and disappeared in patients with Barcelona stage B and C (P > 0.05). The long-term survival advantage existed in patients with Barcelona stage A (P < 0.001), B (P < 0.05), and disappeared in C (P > 0.05). Conclusion: Preoperative albumin/globulin ratio can predict postoperative prognosis and survival, and direct towards the treatment for early stage of HCC and thus representing as an indicator of high clinical value.

[Diagnostic application of serum GP73 and the relevant mechanism in the diagnosis of liver cirrhosis]

Liver cirrhosis is the end-stage change of chronic liver diseases with various causative factors. The accurate diagnosis of liver cirrhosis in an early stage is very important for the timely treatment and prognosis of patients. A liver biopsy test is the gold standard for the diagnosis of liver cirrhosis; but its use is limited in clinical practices due to its invasive nature. The conventional non-invasive measures (APRI, FIB-4 and LSM) for diagnosis of liver cirrhosis could not fulfill the needs. Therefore, finding a new serological marker of liver cirrhosis has become a research hotspot. Based on literature review and our own results, we suggest that serum GP73 as the most potential serum marker for liver cirrhosis diagnosis. This review briefly introduces the application of serum GP73 in the diagnosis of liver cirrhosis and the potential mechanism relevant to its involvement in the development of liver cirrhosis.

[Potential clinical significance of HBV RNA virus-like particle]

Our recent studies confirmed that the HBV RNAs present in the serum of chronic hepatitis B(CHB)patients are pregenomic RNAs(pgRNAs)with a size of 3.5 kb. These pgRNAs are located in virus-like particles whose morphological structure is similar to that of Dan particles. Since pgRNAs can only be transcribed from the covalently closed circular DNA(cccDNA)located in the nuclear of infected hepatocytes, and the production of pgRNAs is not affected by nucleos(t)ide analogues(NUCs), the presence of viral RNA in serum can reflect the presence of cccDNA in hepatocytes and its transcriptional activity in patients treated with medication. It can be inferred that serum viral RNA can be used as a potential index for safe withdrawal of NUCs. Our results based on a small-sample cohort show that the presence of HBV RNA in serum at the time of drugs withdrawal is indeed associated with virological rebound after drug withdrawal.

[The potential use of serum HBV RNA to guide the functional cure of chronic hepatitis B]

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) in infected hepatocytes is the main cause of off-therapy viral rebound. The half-life of cccDNA is only 33-50 days, so the conversion of newly synthesized rcDNA to cccDNA in the nucleus is essential for the maintenance of cccDNA pool in infected hepatocytes. Though not directly targeting the existing cccDNA, current nucleos(t)ide analogues (NAs) may exhaust the cccDNA reservoir by blocking the rcDNA formation. Indeed, a prolonged consolidation therapy post loss of serum HBV DNA can achieve sustained remission and thus safe drug discontinuation in a small proportion of chronic hepatitis B (CHB) patients. In recent studies, we and others have demonstrated that it is the serum HBV RNA that reflects the cccDNA activity in infected hepatocytes, particularly among the patients on NAs. Here we suggest that instead of measuring serum HBV DNA only, simultaneous measurement of both viral DNA and RNA would improve the accuracy to reflect the cccDNA activity; therefore, the virological response should be redefined as consistent loss (less than the lower limit of detection) of both serum HBV DNA and RNA, which indicates the safety of drug discontinuation. Accumulating evidence has suggested that for the CHB patients with lower serum HBsAg, switch-to or add-on pegylated interferon (Peg-IFN) treatment would result in loss of serum HBsAg in a relatively large proportion of CHB patients. Since serum HBV RNA is an ideal biomarker to reflect the intrahepatic cccDNA activity, for the patients with a serum HBsAg level lower than 1 500 IU/ml after long-term NAs treatment, the serum HBV RNA should be measured. If serum HBV RNA is detected, peg-IFN should be added on; if serum HBV RNA is not detected, NAs treatment should be switched to peg-IFN treatment. We believe the therapy based on serum HBV RNA would make the functional cure of CHB (serum HBsAg loss or even conversion to anti-HBs) more efficient.

[Hepatitis B virus X protein-regulated expression of Plk1]

OBJECTIVE

To investigate the ability and underlying mechanism of hepatitis B virus X protein (HBx) regulation of Polo-like kinase 1 (Plk1) expression.

METHODS

The human HCC cell line HepG2 was transfected (transiently and stably) with an HBx plasmid expression vector (pCMV-HA-HBx) or empty plasmid vector (control), with and without expression plasmids with the Plk1 promoter. Effects on Plk1 expression were assessed by western blotting. Functional effects on the Plk1 promoter were assessed by luciferase reporter assay. Effects on the mRNA level of Plk1 in S phase HepG2 cells were assessed by quantitative real-time reverse transcriptase polymerase chain reaction. After blocking protein synthesis by treatment with cycloheximide (CHX), the turnover rate of Plk1 was assessed by western blotting. Lastly, the effect of HBx on cell cycle was assessed by flow cytometry.

RESULTS

HBx did not increase the protein expression of Plk1 in non-synchronized HepG2 cells, but did significantly up-regulate the Plk1 protein level in the synchronized S phase cells (P = 0.026 and P = 0.003, respectively). Ectopic expression of HBx did not increase the mRNA level of Plk1 in HepG2 cells, but did inhibit the degradation of Plk1, as evidenced by an increased half-life of Plk1 protein (from 30 to 90 minutes). The HBx-expressing HepG2 cells showed more frequent entry into the S or G(2)/M phase than the control cells (31.65% vs. 24.56% or 9.43% vs. 4.47%, respectively) and less in the G(0)/G(1) phase (decrease from 70.97% to 58.92% for the HBx-expressing HepG2 cells).

CONCLUSION

HBx is able to up-regulate the expression of Plk1 in HepG2 cells by a mechanism involving stabilization of the Plk1 protein primarily in the S phase of the cell cycl.

Effect of functional nuclear factor-kappaB genetic polymorphisms on hepatitis B virus persistence and their interactions with viral mutations on the risk of hepatocellular carcinoma

BACKGROUND

Nonresolving inflammation and viral mutations are important in hepatitis B virus (HBV)-induced hepatocarcinogenesis. However, the effects of genetic polymorphisms affecting nuclear factor-kappaB (NF-κB) on HBV persistence and generation of hepatocellular carcinoma (HCC)-related HBV mutations remain unknown.

PATIENTS AND METHODS

rs28362491 (NFKB1 -94Ins > Del), rs2233406 (NFKBIA -826C > T), rs3138053 (NFKBIA -881A > G), and rs696 (NFKBIA +2758G > A) were genotyped in 1342 healthy controls, 327 HBV-clearance subjects, and 3976 HBV-positive subjects including 1495 HCC patients, using quantitative PCR. HBV mutations were determined by sequencing. The NFKBIA promoter activity was assessed by transient transfection. Multiplicative interactions of the polymorphisms and viral mutations were assessed by multivariate logistic regression.

RESULTS

Compared with HBV-clearance subjects, rs2233406 (CT versus CC) and rs3138053 (AG or AG + GG versus AA) significantly decreased HBV persistence, especially in the genotype B HBV-infected subjects. In the genotype C HBV-infected subjects, rs2233406 variant genotypes were significantly associated with an increased risk of HCC [CT versus CC: age-, gender-adjusted odds ratio (AOR), 1.33; 95% confidence interval (CI) 1.01-1.75 in training set and AOR, 1.59; 95% CI 1.01-2.52 in validation set] compared with HCC-free HBV-infected subjects and significantly increased the frequencies of HCC-related HBV mutations (A1762T/G1764A, T1753V, preS1 start codon mutation, and preS deletion); rs28362491 (Del/Del or Ins/Del + Del/Del versus Ins/Ins) significantly increased the frequency of A1762T/G1764A and reduced the frequency of preS2 start codon mutation. The variant genotypes impaired NFKBIA promoter activity in hepatic cells. The interaction of rs2233406 variant genotypes (CT + TT versus CC) with A1762T/G1764A significantly increased HCC risk in genotype C HBV-infected subjects, with AOR of 2.61 (95% CI 1.09-6.26).

CONCLUSION

Genetic polymorphisms improving NF-κB activity contribute to genotype B HBV clearance. The rs2233406 variant genotypes significantly increase HCC risk, possibly via facilitating immune selection of the HBV mutations. The host-virus interactions are important in identifying HBV-infected subjects who are more likely to develop HCC.

Unique features of PTCH1 mutation spectrum in Chinese sporadic basal cell carcinoma

BACKGROUND

Alterations of the PTCH1 gene have been found to contribute to both familial and sporadic basal cell carcinoma (BCC), especially in Caucasian patients. Furthermore, the majority of PTCH1 gene mutations in sporadic BCCs in Caucasian patients carry ultraviolet (UV) signatures, suggesting the key role of UV light in BCC development. However, sporadic BCC in non-Caucasian population has a lower incidence, and the pathogenesis remains largely unknown. To date, there has been no mutation analysis on PTCH1 gene in Chinese patients with sporadic BCCs.

OBJECTIVE

To investigate genetic alterations of the PTCH1 gene in Chinese sporadic BCCs.

METHODS

Direct sequencing was used to screen for mutations in PTCH1 in 31 microdissected samples in Chinese sporadic BCCs. In addition, single nucleotide polymorphisms (SNPs) were studied for loss of heterozygosity (LOH).

RESULTS

Nineteen PTCH1 mutations in 17 of the 31 BCCs (54.8%) were identified. SNP analysis revealed LOH of PTCH1 in 10 of 23 BCCs (43.5%). Interestingly, the majority of mutations identified (63.2%) were insertion/deletion, which was different from the results in Caucasian cases whose mutations are predominantly point mutations. Only two (10.5%) of the remaining seven mutations were UV-specific C → T transition or tandem CC → TT transitions. All mutations occurred evenly throughout the entire PTCH1 protein domain without a hot-spot detected.

CONCLUSION

Mutations and LOH in PTCH1 were also highly prevalent in Chinese sporadic BCCs. However, UV light plays a less role in causing these mutations, suggesting other potential mechanisms in the development of sporadic BCC in Chinese patients.

Epidemiology and prevention of hepatitis B virus infection in China

The concept of a hepatitis B vaccine was first introduced into China in 1978. China has been one of the first two developing countries to enact the universal hepatitis B vaccination programme for newborn babies in 1992, and has made tremendous achievements in the control of hepatitis B virus (HBV) infection since then. China now has both low and high endemic regions regarding HBV prevalence co-existing. Although China's drive to stop HBV spread has resulted in changes in HBV epidemic patterns, for the eventual elimination HBV infection in China, it is important to understand the current status of its epidemiology and the aspects of HBV transmission in different regions. More efforts are needed to improve and develop strategies for the control of HBV infection in China, particularly after implementing the policy of universal HBV immunization for all newborns.

Induction treatment of proliferative lupus nephritis with leflunomide combined with prednisone: a prospective multi-centre observational study

To evaluate the efficacy and safety of leflunomide in the treatment of proliferative lupus nephritis, a prospective multi-centre observational study was conducted. Patients with biopsy proven proliferative lupus nephritis were assigned to receive either leflunomide or cyclophosphamide with concomitant prednisone. Leflunomide was given orally with a loading dose of 1 mg/kg/day for 3 days followed by 30 mg/day. Intravenous cyclophosphamide was administered monthly at a dose of 0.5 g/m2 of body-surface area. A total of 110 patients were enrolled, 70 in the leflunomide group and 40 in the cyclophosphamide group. The complete remission rate in the leflunomide group was 21% and partial remission rate 52%, as compared with 18% and 55%, respectively, in the cyclophosphamide group. Renal parameters and systemic lupus erythematosus disease activity index improved significantly and similarly in both groups. Serum creatinine decreased or stabilized in both treatment groups. No significant difference was noted with respect to clinical outcome between groups. Repeat biopsy also showed a significant reduction of active lesions in kidney pathology after 6 months of leflunomide treatment. Major adverse events, similar in both treatment groups, included infection, alopecia and hypertension. Leflunomide, compared with cyclophosphamide, in combination with prednisone was effective in the induction therapy of proliferative lupus nephritis and was generally well-tolerated.

Redox potential of tea infusion as an index for the degree of fermentation

Redox potential of tea infusion is suggested as an index for the extent of tea fermentation. The potential was measured between platinum and Ag/AgCl electrode pair with a voltmeter with high input impedance (>1000 Gohms). Phosphate buffer (10 mM, pH 7.0) was used to extract the infusion and served as the supporting electrolytes for the electrochemical measurement. The reliability (the Nernst's behavior) for redox potential measurement was verified with a standard redox couple, ferricyanide/ferrocyanide. Tentative interferences from dissolved oxygen and the major coexisting reducing chemical, ascorbate, were discussed. Redox potential showed strong correlation with the fermentation process during indoor withering process. Eleven kinds of tea with different fermentation extents including Sencha, Pilochun, Pouchong, Formosa oolong tea, Lipton green tea, Lipton black tea, and Taiwanese black tea were tested.

Antimicrobial coatings: a remedy for medical device-related infections

This article discusses the mechanisms involved in the different approaches to antimicrobial coatings and reports on a new application that seems to offer an antimicrobial surface that is effective for long-term medical implants and suitable for a variety of drugs.

Synchronized Ca2+signals mediated by Ca2+action potentials in the hippocampal neuron network in vitro

Periodic, synchronized Ca2+ signals appeared 30-120 min after the application of tetrodotoxin, 4-aminopyridine and Cs+, and became stable in interval (6-47s) for hours. The Ca2+ signals were accompanied by excitatory or inhibitory postsynaptic potentials (excitatory postsynaptic currents (EPSCs) for the former) and blocked by the simultaneous application of 6-cyano-7-nitroquinoxaline-2,3-dione and 3-((RS)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid or treatment with Ca2+ -free solution, nicardipine, or omega-conotoxin MVIIC (omegaCTX), but not with ryanodine, caffeine, thapsigargin or CPP alone. Nicardipine largely, but omegaCTX less, blocked Ca2+ action potentials or voltage pulse-induced Ca2+ currents at the cell soma, while omegaCTX completely blocked autaptic EPSCs. Ca2+ signals within a neuron occurred almost simultaneously in the cell soma and all the processes (> 200 microm), while the latency between Ca2+ signals of neighbouring neurons varied over hundreds of ms like that of Ca2 action potential induction from EPSPs. Ca2+ signals propagated in random directions throughout neural circuits. Thus, when Na+ and K+ channels are blocked, Ca2+ action potentials spontaneously occur somewhere in a neuron, eventually propagate via the cell soma to the presynaptic terminals and activate excitatory synaptic transmission, causing synchronized Ca2+ signals. The results further suggest that the axon of hippocampal neurones have the potential ability to convey coded information via Ca2+ action potentials.

Mutation analysis of Jagged1 (JAG1) in Alagille syndrome patients

Alagille syndrome (AGS) is an autosomal dominant disorder caused by mutations in Jagged1 (JAG1), a ligand in the evolutionarily conserved Notch signaling pathway. Previous studies have demonstrated that a wide spectrum of JAG1 mutations result in AGS. These include total gene deletions, protein truncating, splicing and missense mutations which are distributed across the coding region of the gene. Here we present results of JAG1 mutation screening by SSCP and FISH in 105 patients with AGS. For these studies, new primers were designed for 12 exons. Mutations were identified in 63/105 patients (60%). The spectrum of the JAG1 mutations presented here is consistent with previously reported results. Eighty three percent (52/63) of the mutations were protein truncating, 11% (7/63) were missense, 2% (1/63) were splice site, and 5% (3/63) were total gene deletions demonstrable by FISH. Six of the missense mutations are novel. As has been reported previously, there is no apparent relationship between genotype and clinical phenotype.

Two-chain high molecular weight kininogen induces endothelial cell apoptosis and inhibits angiogenesis: partial activity within domain 5

We previously reported that the binding of two-chain high molecular weight kininogen (HKa) to endothelial cells may occur through interactions with endothelial urokinase receptors. Since the binding of urokinase to urokinase receptors activates signaling responses and may stimulate mitogenesis, we assessed the effect of HKa binding on endothelial cell proliferation. Unexpectedly, HKa inhibited proliferation in response to several growth factors, with 50% inhibition caused by approximately 10 nM HKa. This activity was Zn(2+) dependent and not shared by either single-chain high molecular weight kininogen (HK) or low molecular weight kininogen. HKa selectively inhibited the proliferation of human umbilical vein and dermal microvascular endothelial cells, but did not affect that of umbilical vein or human aortic smooth muscle cells, trophoblasts, fibroblasts, or carcinoma cells. Inhibition of endothelial proliferation by HKa was associated with endothelial cell apoptosis and unaffected by antibodies that block the binding of HK or HKa to any of their known endothelial receptors. Recombinant HK domain 5 displayed activity similar to that of HKa. In vivo, HKa inhibited neovascularization of subcutaneously implanted Matrigel plugs, as well as rat corneal angiogenesis. These results demonstrate that HKa is a novel inhibitor of angiogenesis, whose activity is dependent on the unique conformation of the two-chain molecule.

Modes of propagation of Ca(2+)-induced Ca2+ release in bullfrog sympathetic ganglion cells

How depolarization-induced Ca2+ entry or caffeine activates Ca(2+)-induced Ca2+ release (CICR) in the cytoplasm and nucleoplasm was studied by recording intracellular Ca2+ ([Ca2+]i) with a confocal microscope in cultured bullfrog sympathetic ganglion cells. The amplitude and propagation speed of voltage pulse-induced rises in [Ca2+]i were greater in the submembrane (< 5 microns depth) region than in the core region, and delayed and smaller, but significant, in the nucleus. Ryanodine and dantrolene reduced the rises in [Ca2+]i in both the cytoplasm and nucleus. A rapid application of high K+ solution induced global rises in [Ca2+]i in both the cytoplasm and nucleoplasm, which were decreased by dantrolene. Caffeine produced a slow, small rise in [Ca2+]i which grew into a global, regenerative rise both in the cytoplasm and nucleoplasm with some inward gradient in the cytoplasm. Each of the high [Ca2+]i phases during caffeine-induced [Ca2+]i oscillation began in the submembrane region, while low [Ca2+]i phases started in the core region. These results suggest that CICR activated by Ca2+ entry or caffeine occurs predominantly in the submembrane region causing an inwardly spreading Ca2+ wave or [Ca2+]i oscillations, and that the nuclear envelope can cause CICR in the nucleoplasm, which is delayed due to Ca2+ diffusion barrier at the nuclear pores.

Mammalian Notch1 is modified with two unusual forms of O-linked glycosylation found on epidermal growth factor-like modules

Notch is a large cell-surface receptor known to be an essential player in a wide variety of developmental cascades. Here we show that Notch1 endogenously expressed in Chinese hamster ovary cells is modified with O-linked fucose and O-linked glucose saccharides, two unusual forms of O-linked glycosylation found on epidermal growth factor-like (EGF) modules. Interestingly, both modifications occur as monosaccharide and oligosaccharide species. Through exoglycosidase digestions we determined that the O-linked fucose oligosaccharide is a tetrasaccharide with a structure identical to that found on human clotting factor IX: Sia-alpha2,3-Gal-beta1, 4-GlcNAc-beta1,3-Fuc-alpha1-O-Ser/Thr. The elongated form of O-linked glucose appears to be a trisaccharide. Notch1 is the first membrane-associated protein identified with either O-linked fucose or O-linked glucose modifications. It also represents the second protein discovered with an elongated form of O-linked fucose. The sites of glycosylation, which fall within the multiple EGF modules of Notch, are highly conserved across species and within Notch homologs. Since Notch is known to interact with its ligands through subsets of EGF modules, these results suggest that the O-linked carbohydrate modifications of these modules may influence receptor-ligand interactions.

Hierarchical order of critical residues on the immunity-determining region of the Im7 protein which confer specific immunity to its cognate colicin

The directed mutagenesis study of the Im7 protein of colicin E7 revealed that three residues, D31, D35, and E39, located in the loop 1 and helix 2 regions of the protein were critical for initiating the complex formation with its cognate colicin E7. Interestingly, the importance of these three critical residues in conferring specific immunity to its own colicin was exhibited in a hierarchical order, respectively. Moreover, we found that existence of the three critical residues was common among the DNase-type Im proteins. Most likely the three residues of the DNase-type immunity proteins are critical for initiating the unique protein-protein interactions with their cognate colicin. In addition, replacement of the helix 2 of Im7 by the corresponding region of Im8 produced a phenotype of the mutant protein very similar to that of Im8. This result suggests that the DNase-type Im proteins indeed share a "homologous-structural framework" and evolution of the Im proteins may be engendered by minor amino acid changes in this specific immunity-determining region without causing structural alteration of the proteins.

Notch1 inhibits neurite outgrowth in postmitotic primary neurons

Notch plays an important role in cell fate decisions in uncommitted proliferative cells, including neurogenesis, but is believed to not have a role in postmitotic cells. We have shown previously that Notch1 is highly expressed in embryonal mouse and human brain, but surprisingly it continues to be expressed at low levels in the adult brain. The function of Notch1 in postmitotic neurons in mammals is unknown. To better understand the potential role of Notch1 in mature central nervous system neurons we studied the effect of Notch1 transfection on neurite outgrowth in primary neocortex hippocampal neurons. Transfection at two days in vitro with full length Notch1 inhibited neurite outgrowth. Transfection at five to six days in vitro, after neurite outgrowth was established, led to apparent regression of neurites. These effects were enhanced when truncated constitutively active forms of Notch1 were introduced. Co-transfection with Numb, a physiological inhibitor of Notch, blocked Notch's effect on neurite outgrowth. We also examined whether Notch1 could activate C-promoter binding factor (CBF1) transcription factor using C-promoter binding factor-luciferase constructs, and demonstrated that this signal transduction pathway is present and can be activated in postmitotic neurons. Our results show that in postmitotic neurons Notch1 influences neurite morphology, and can activate its native signal transduction pathway. These data strongly suggest that Notch1 may play a physiologically important role in the central nervous system beyond neurogenesis.

The activation of protein kinase C induces higher production of reactive oxygen species by mononuclear cells in patients with multiple sclerosis than in controls

OBJECTIVE

Recent findings have increasingly shown the importance of reactive oxygen species (ROS) in causing oxidative damage to macromolecules and in contributing to tissue degeneration in target organs of autoimmune diseases. This study was aimed at comparing the base line and induced production of ROS by peripheral blood mononuclear cells (PB MNCs) of patients with multiple sclerosis (MS) in remission and relapse, of patients with other neurological diseases (OND) and of healthy controls. In addition, we analyzed the underlying mechanism of ROS production.

METHODS

PB MNCs were separated from 28 MS patients in remission and 13 in relapse, and from 29 healthy controls and 10 OND. ROS was measured by spectrofluorometry. Expression of proinflammatory cytokines was assessed by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Mitochondrial (mt) DNA haplotypes were determined by using restriction site polymorphism analysis.

RESULTS

The base line and tumor necrosis factor (TNF)-alpha or interferon (IFN)-gamma induced ROS values were similar in the four groups, and the individual measures did not show a correlation with MS associated mtDNA haplotypes. Phorbol ester activation of protein kinase C (PKC) induced higher ROS production in all groups, however, with significantly greater values in the MS remission group. Calphostine C, a PKC inhibitor decreased or eliminated ROS production in a dose-dependent manner, suggesting further that it was predominantly or exclusively generated by PKC activated NADPH oxidase. A trend of increased TNF-alpha and IFN-gamma expression was noted in the MS relapse group, in contrast to the high ROS release in the MS remission group.

CONCLUSION

The detected phase difference between the highest ROS production vs TNF-alpha expression is compatible with the hypothesis that different subpopulations of monocytes/macrophages are involved. We suggest that the ROS producing subpopulation preferentially migrates into the central nervous system (CNS) during a relapse. The present study together with our previous observation on oxidative damage to DNA in active plaques delineates a molecular pathway likely involved in the histologic evolution of inflammatory demyelination.

The Alzheimer-related gene presenilin 1 facilitates notch 1 in primary mammalian neurons

The normal functional neurobiology of the Alzheimer's disease (AD) related gene presenilin 1 (PS1) is unknown. One clue comes from a genetic screen of Caenorhabditis elegans, which reveals that the presenilin homologue sel-12 facilitates lin-12 function [D. Levitan, I. Greenwald, Facilitation of lin-12-mediated signalling by sel-12, a Caenorhabditis elegans S182 Alzheimer's disease gene, Nature 377 (1995) 351-355]. The mammalian homologue of lin-12, Notch1, is a transmembrane receptor that plays an important role in cell fate decisions during development, including neurogenesis, but does not have a known function in fully differentiated cells. To better understand the potential role of Notch1 in mammalian postmitotic neurons and to test the hypothesis that Notch and PS 1 interact, we studied the effect of Notch1 transfection on neurite outgrowth in primary cultures of hippocampal/cortical neurons. We demonstrate that Notch1 inhibits neurite extension, and thus has a function in postmitotic mature neurons in the mammalian CNS. Furthermore, we present evidence demonstrating that there is a functional interaction between PS1 and Notch1 in mammalian neurons, analogous to the sel-12/lin-12 interaction in vulval development in C. elegans [D. Levitan, T. Doyle, D. Brousseau, M. Lee, G. Thinakaran, H. Slunt, S. Sisodia, I. Greenwald, Assessment of normal and mutant human presenilin function in Caenorhabditis elegans, Proc. Natl. Acad. Sci. U.S.A. 93 (1996) 14940-14944; D. Levitan, I. Greenwald, Effect of Sel-12 presenilin on Lin-12 localization and function in Caenorhabditis elegans, Development, 125 (1998) 3599-3606]. The inhibitory effect of Notch1 on neurite outgrowth is markedly attenuated in neurons from PS1 knockout mice, and enhanced in neurons from transgenic mice overexpressing wild type PS1, but not mutant PS1. These data suggest that PS1 facilitates Notch1 function in mammalian neurons, and support the hypothesis that a functional interaction exists between PS1 and Notch1 in postmitotic mammalian neurons.

Ataxia-telangiectasia and T-cell leukemias: no evidence for somatic ATM mutation in sporadic T-ALL or for hypermethylation of the ATM-NPAT/E14 bidirectional promoter in T-PLL

The ATM gene deficient in ataxia-telangiectasia, a recessive multisystem disease associated with a high risk of lymphomas and leukemias, was found previously to be inactivated in a rare sporadic malignancy, T-cell prolymphocytic leukemia (T-PLL), which is often associated with cytogenetic aberrations of chromosome 14. The ATM gene was shown to sustain frequent loss-of-function mutations in T-PLL tumor cells, consistent with functioning as a tumor suppressor gene in this leukemia. To investigate the possibility of nonmutational or nonrecombinational mechanisms of T-PLL development, we have used bisulfite genomic sequencing to analyze DNA methylation in the putative bidirectional promoter region of the closely linked ATM and NPAT/E14 genes within the CpG island at 11q22-q23. We show that this region is completely demethylated in lymphocytes expressing ATM; however, no extensive hypermethylation was found in 9 T-PLL tumor DNA samples without evidence of ATM/p53 mutations. Because acute T-cell lymphoblastic leukemias (T-ALL) were also observed in ataxia-telangiectasia patients and T-ALL tumor cells contain chromosome 14 abnormalities, 19 presentation samples of T-ALL patients were analyzed for ATM mutations. Although T-ALL patients exhibited rare nucleotide substitutions not previously found in ATM, all were identified in the germ-line, indicating constitutional polymorphisms, potentially confined to ethnic subpopulations. The absence of somatic nucleotide changes in ATM in T-ALL as compared with T-PLL suggests a distinct pattern of genetic events in the development of the two leukemias.

Immunologic changes during immunotherapy in asthmatic children: increased IL-13 and allergen-specific IgG4 antibody levels

BACKGROUND

The prevalence of allergic diseases such as asthma, allergic rhinitis, and atopic diseases has increased in recent years. Immunotherapy with allergens is a treatment documented to have an effect on regulating cytokine production and allergen-specific antibody production.

OBJECTIVE

The aim of this study was to further investigate immunologic changes during immunotherapy and to explore the possible more efficient approach of immunotherapy.

METHODS

Asthmatic children receiving house dust mite immunotherapy were followed to learn immunologic parameters such as allergen-specific antibody levels, proliferative response of peripheral blood mononuclear cells, and cytokine change during immunotherapy.

RESULTS

The data suggested (1) IgG4 anti-mite antibody increased 8 months after immunotherapy while IgE antibody level remained the same; (2) allergen-induced, in vitro production of certain cytokines such as IL-4 and IL-10 decreased after immunotherapy; (3) IL-13 (which can induce IgG4 and IgE antibody production by B cells) increased after immunotherapy.

CONCLUSION

Although this needs more study, IL-13 might play an important role in the generation of IgG4-blocking antibody during immunotherapy.

Change of chemokines during immunotherapy in asthmatic children

Histamine-releasing factor (HRF) consists of a group of cytokines that can cause basophil/mast cell to release histamine, however, the composition of HRF still remains undefined. This study was designed to measure the concentrations of chemokines in asthmatic children receiving immunotherapy. Peripheral blood mononuclear cells culture supernatants were obtained from six asthmatic children before and four, eight months after immunotherapy (IT). The levels of monocyte chemotactic and activating factor (MCAF), macrophage inflammatory protein-1a (MIP-1a), regulated on activation normal T-cell expressed and secreted (RANTES) and interleukin-8 (IL-8) spontaneously and after stimulation with PHA and mite allergen in the supernatants. The data showed: 1) The levels of MCAF and MIP-1a increased four months, and decreased eight months, after IT; 2) By contrast, the level of RANTE increased after IT; 3) The level of IL-8 also tended to increase after IT. Abnormal chemokine production may contribute to the pathogenesis of bronchial asthma and restoration of normal chemokine production may be used to partially explain the clinical efficacy of immunotherapy.

Two overlapping SOS-boxes in ColE operons are responsible for the viability of cells harboring the Col plasmid

In this study, oligonucleotide-directed site-specific mutagenesis was used to change the consensus sequences of the LexA binding motifs in either one of the two SOS-boxes of the ColE7 operon. The results indicated that both mutants produced larger amounts of colicin than cells harboring the wild-type ColE7 plasmid. This finding would imply that two biologically functional SOS boxes exist in the ColE7 operon. In the non-induced state, no lysis of cells harboring wild-type plasmids occurred at 37 degrees C, whereas, cells harboring recombinant plasmids containing either one of the mutated SOS boxes underwent lysis within 100 min under the same conditions. This result indicated that adaptation of two SOS boxes of the ColE operon would obviously tightly control the expression of ColE operons. In such a way that it may prevent excessive expression of the lysis (cel) gene, thus safeguard the host cells from being lysed in ordinary living conditions.

Constitutively active human Notch1 binds to the transcription factor CBF1 and stimulates transcription through a promoter containing a CBF1-responsive element

Notch is a transmembrane receptor that plays a critical role in cell fate determination. In Drosophila, Notch binds to and signals through Suppressor of Hairless. A mammalian homologue of Suppressor of Hairless, named CBF1 (or RBPJk), is a ubiquitous transcription factor whose function in mammalian Notch signaling is unknown. To determine whether mammalian Notch can stimulate transcription through a CBF1-responsive element (RE), we cotransfected a CBF1-RE-containing chloramphenicol acetyltransferase reporter and N1(deltaEC), a constitutively active form of human Notch1 lacking the extracellular domain, into DG75, COS-1, HeLa, and 293T cells, which all contain endogenous CBF1. N1(deltaEC) dramatically increased chloramphenicol acetyltransferase activity in these cells, indicating functional coupling of Notch1 and CBF1. The activity was comparable to that produced by the Epstein-Barr virus protein EBNA2, a well-characterized, potent transactivator of CBF1. To test whether CBF1 and Notch1 interact physically, we tagged CBF1 with an epitope from the influenza virus hemagglutinin or with the N-terminal domain of gal4, and transfected the tagged CBF1 plus N1(deltaEC) into COS-1 cells. Cell lysates were immunoprecipitated and immunoblotted with several anti-Notch1 antibodies [to detect N1(deltaEC)] or with antibodies to hemagglutinin or gal4 (to detect CBF1). Each immunoprecipitate contained a complex of N1(deltaEC) and CBF1. In summary, we find that the truncated, active form of human Notch1, N1(deltaEC), binds CBF1 and activates transcription through a CBF1-RE-containing promoter. We conclude that CBF1 is a critical downstream protein in the human Notch1 signaling pathway.

Ank3 (epithelial ankyrin), a widely distributed new member of the ankyrin gene family and the major ankyrin in kidney, is expressed in alternatively spliced forms, including forms that lack the repeat domain

We cloned a novel ankyrin, Ank3, from mouse kidney cDNA. The full-length transcript is predicted to encode a 214-kD protein containing an 89 kD, NH2 terminal "repeat" domain; a 65 kD, central "spectrin-binding" domain; and a 56 kD, COOH-terminal "regulatory" domain. The Ank3 gene maps to mouse Chromosome 10, approximately 36 cM from the centromere, a locus distinct from Ank1 and Ank2. Ank3 is the major kidney ankyrin. Multiple transcripts of approximately 7.5, 6.9, 6.3, 5.7, 5.1, and 4.6 kb are highly expressed in kidney where Ank1 and Ank2 mRNAs are barely detectable. The smaller mRNAs (< or = 6.3 kb) lack the entire repeat domain. These transcripts have a unique 5'untranslated region and NH2-terminal sequence and encode a predicted protein of 121 kD. Two small sequences of 21 and 18 amino acids are alternatively spliced at the junction of the repeat and spectrin-binding domains in the larger (> or = 6.9 kb) RNAs. Alternative splicing of a 588 bp sequence (corresponding to a 21.5-kD acidic amino acid sequence) within the regulatory domain also occurs. Ank3 is much more widely expressed than previously described ankyrins. By Northern hybridization or immunocytochemistry, it is present in most epithelial cells, in neuronal axons, in muscle cells, and in megakaryocytes/platelets, macrophages, and the interstitial cells of Leydig (testis). On immunoblots, an antibody raised to a unique regions of the regulatory domain detects multiple Ank3 isoforms in the kidney (215, 200, 170, 120, 105 kD) and in other tissues. The 215/200 kD and 120/105-kD kidney proteins are close to the sizes predicted for the 7.5/6.9- and 6.3/5.7-kb RNAs (with/without the 588-bp acidic insert). Interestingly, it appears that Ank3 exhibits a polarized distribution only in tissues that express the approximately 7.0-kb isoforms, the only isoforms in the kidney that contain the repeat domain. In tissues where smaller transcripts (< or = 6.3 kb) are expressed. Ank3 is diffusely distributed in some or all cells and may be associated with cytoplasmic structures. We conclude that Ank3 is a broadly distributed epithelial ankyrin and is the major ankyrin in the kidney and other tissues, where it plays an important role in the polarized distribution of many integral membrane proteins.

[The pharmacology of the GABA-induced biphasic response in guinea-pig celiac ganglion neurons in vitro]

In guinea-pig celiac ganglion neurons, GABA induced a biphasic response, i.e. a depolarizing response associated with a resistance decrease followed by a hyperpolarizing response associated with a resistance increase. Such response persisted in low Ca2+ high Mg2+ medium. The GABA-induced biphasic response was mimicked by muscimol and inhibited by bicuculline methiodide (100 mumol/L) and picrotoxin (100-300 mumol/L). At doses producing almost equal depolarizing responses, muscimol was weaker in producing hyperpolarizing responses than GABA. Baclofen had no effect on membrane potentials of the ganglion cells. These results suggest that the depolarizing phase of the GABA-induced biphasic response is mediated by GABAA/Cl- ionophore receptor complex and the hyperpolarizing phase may be mediated by a novel type of GABA receptor possessing similar pharmacological properties as the classical GABAA receptor.

Characterization of the cea gene of the ColE7 plasmid

The complete nucleotide sequence (1731 nucleotides) of the gene encoding colicin E7 (cea) of plasmid ColE7-K317 was determined. This sequence encoded a deduced polypeptide of 576 amino acids of molecular weight 61349 Da. Comparison of the nucleotide and amino acid sequences of cea E7 with those of other E-group colicins revealed that colicin E7 was closely related to colicin E2, both in gene sequence and in predicted secondary structure of the deduced protein. Judging from the results of cross-immunity tests, we postulated that ColE7 is probably a proximate ancestor of ColE2 and ColE8. Based on results from colicin production tests on cells harboring a 5' end deleted form of the cea E7 gene, we propose that a previously unknown, non-inducible promoter may be involved in regulation of the constitutive expression of the cea E7 gene.

Cloning and characterization of the ColE7 plasmid

The 6.2 kb ColE7-K317 plasmid was mapped and the DNA fragments of the colicin E7 operon subcloned into pUC18 and pUC19. The size of the functional colicin E7 operon deduced by subcloning was 2.3 kb. The colicin E7 gene product was purified by carboxymethylcellulose chromatography. Both colicin E7 and E9 were demonstrated to exhibit a non-specific DNAase-type activity by in vitro biological assay. The molecular mass of colicin E7 was 61 kDa, as determined by SDS-PAGE. From DNA sequence data, the estimated sizes of the E7 immunity protein and the E7 lysis protein were 9926 Da and 4847 Da, respectively. Comparison of restriction maps and DNA sequence data suggests that ColE7 and ColE2 are more closely related than other E colicin plasmids.

Effects of FDP and Danshen on renal cortical Na-K-ATPase activity in rats after treatment with renal ischemia and gentamicin

The main purpose of our study is to investigate the possible protective effects of Fructose 1-6 diphosphate (FDP) and Danshen (Salvia Miltiozzhiza Bunze) on renal cortical Na-K-ATPase activity after renal ischemia and gentamicin nephrotoxicity. An 18.6% reduction in renal cortical Na-K-ATPase activity was shown after 30 min of renal pedicle clamping and 60 min of reflow, and a 32.5% reduction after 90 min of single injection of 100 mg/kg gentamicin. Light and electronic microscopy revealed no significant morphologic changes in both groups in the experiment. 4g/kg FDP and 18g/kg Danshen were infused 60 min after reflow in the ischemic group, 90 min after injection of gentamicin in the gentamicin-treated group and 90 min in the sham-operated group separately. The enzyme activity in the FDP-treated groups was found to be higher than that in the control kidneys while in the Danshen-treated groups no significant difference could be found. Our study showed that FDP and Danshen could prevent the decline of renal cortical Na-K-ATPase activity induced by ischemia and gentamicin. FDP could increase this enzyme activity while Danshen showed no such direct effect.