Metabolic-associated fatty liver disease and hepatocellular carcinoma: a prospective study of characteristics and response to therapy

BACKGROUND AND AIM

The rising incidence of hepatocellular carcinoma (HCC) in Australia is related to increasing rates of metabolic-associated fatty liver disease (MAFLD). This study aimed to prospectively characterize the metabolic profile, lifestyle, biometric features, and response to treatment of HCC patients in an Australian population.

METHOD

Multicenter prospective cohort analysis of newly diagnosed HCC patients at six multidisciplinary team meetings over a 2-year period.

RESULTS

Three hundred and thirteen (313) newly diagnosed HCC patients with MAFLD (n = 77), MAFLD plus other liver disease (n = 57) (the "mixed" group), and non-MAFLD (n = 179) were included in the study. Alcohol-associated liver disease (ALD) (43%) and MAFLD (43%) were the most common underlying liver diseases. MAFLD-HCC patients were older (73 years vs 67 years vs 63 years), more likely to be female (40% vs 14% vs 20%), less likely to have cirrhosis (69% vs 88% vs 85%), showed higher ECOG, and were less likely to be identified by screening (29% vs 53% vs 45%). Metabolic syndrome was more prevalent in the MAFLD and mixed groups. The severity of underlying liver disease and HCC characteristics were the same across groups. While the MAFLD population self-reported more sedentary lifestyles, reported dietary patterns were no different across the groups. Dyslipidemia was associated with tumor size, and those taking statins had a lower recurrence rate.

CONCLUSION

Equal to ALD, MAFLD is now the most common underlying liver disease seen in HCC patients in Australia. Future HCC prevention screening and treatment strategies need to take this important group of patients into consideration.

Irreversible Electroporation For Hepatocellular Carcinoma: Longer-Term Outcomes At A Single Centre

BACKGROUND AND AIMS

Irreversible electroporation (IRE) is a non-thermal ablation technique for unresectable hepatocellular carcinoma (HCC) not amenable to standard thermal ablation. The aim of this study was to report our longer-term outcomes using this treatment modality.

METHOD

We identified all patients at our institution who underwent IRE for HCC between December 2008 and October 2019 as recommended after multi-disciplinary team review. Demographic, clinical, tumour response and survival data up until 1 March, 2020 were analysed. The primary outcome was local recurrence-free survival (LRFS) in patients who had a complete response (CR). Secondary outcomes included CR rates, procedure-related complications and the incidence of death or liver transplantation.

RESULTS

A total of 23 patients (78% males, median age 65.2 years) received IRE therapy to 33 HCC lesions during the study period with the median tumour size being 2.0 cm (range 1.0-5.0 cm). Twenty-nine (87.9%) lesions were successfully ablated after one (n = 26) or two (n = 3) procedures. The median follow-up time for these lesions was 20.4 months. The median overall LRFS was 34.5 (95% CI 24.8 -) months with a 6- and 12-month LRFS of 87.9% (95% CI 75.8-100) and 83.6% (95% CI 70.2-99.7), respectively. Tumours < 2 cm had a 12-month LRFS of 100% (95% CI 100-100).

CONCLUSION

IRE appears to be an efficacious local ablative method for early stage HCC not amenable to standard ablative techniques, with very good CR rates and longer-term LRFS, particularly for smaller lesions. Further studies comparing this technique to more widely accepted ablative methods such as radiofrequency and microwave ablation are warranted.

Ionic Coulomb blockade and the determinants of selectivity in the NaChBac bacterial sodium channel

Mutation-induced transformations of conductivity and selectivity in NaChBac bacterial channels are studied experimentally and interpreted within the framework of ionic Coulomb blockade (ICB), while also taking account of resonant quantised dehydration (QD) and site protonation. Site-directed mutagenesis and whole-cell patch-clamp experiments are used to investigate how the fixed charge Q_f at the selectivity filter (SF) affects both valence selectivity and same-charge selectivity. The new ICB/QD model predicts that increasing ∣Q_f∣ should lead to a shift in selectivity sequences toward larger ion sizes, in agreement with the present experiments and with earlier work. Comparison of the model with experimental data leads to the introduction of an effective charge Q_f^∗ at the SF, which was found to differ between Aspartate and Glutamate charged rings, and also to depend on position within the SF. It is suggested that protonation of the residues within the restricted space of the SF is important in significantly reducing the effective charge of the EEEE ring. Values of Q_f^∗ derived from experiments on divalent blockade agree well with expectations based on the ICB/QD model and have led to the first demonstration of ICB oscillations in Ca²⁺ conduction as a function of the fixed charge. Preliminary studies of the dependence of Ca²⁺ conduction on pH are qualitatively consistent with the predictions of the model.

Community-based provision of direct-acting antiviral therapy for hepatitis C: study protocol and challenges of a randomized controlled trial

BACKGROUND

To achieve the World Health Organization hepatitis C virus (HCV) elimination targets, it is essential to increase access to treatment. Direct-acting antiviral (DAA) treatment can be provided in primary healthcare services (PHCS), improving accessibility, and, potentially, retention in care. Here, we describe our protocol for assessing the effectiveness of providing DAAs in PHCS, and the impact on the HCV care cascade. In addition, we reflect on the challenges of conducting a model of care study during a period of unprecedented change in HCV care and treatment.

METHODS

Consenting patients with HCV infection attending 13 PHCS in Australia or New Zealand are randomized to receive DAA treatment at the local tertiary institution (standard care arm), or their PHCS (intervention arm). The primary endpoint is the proportion commenced on DAAs and cured. Treatment providers at the PHCS include: hepatology nurses, primary care practitioners, or, in two sites, a specialist physician. All PHCS offer opioid substitution therapy.

DISCUSSION

The Prime Study is the first real-world, randomized, model of care study exploring the impact of community provision of DAA therapy on HCV-treatment uptake and cure. Although the study has faced challenges unique to this period of time characterized by changing treatment and service delivery, the data gained will be of critical importance in shaping health service policy that enables the elimination of HCV.

TRIAL REGISTRATION

ClinicalTrials.gov , ID: NCT02555475 . Registered on 15 September 2015.

Efficacy and safety of 12 weeks of elbasvir ± grazoprevir ± ribavirin in participants with hepatitis C virus genotype 2, 4, 5 or 6 infection: The C-SCAPE study

People with hepatitis C virus (HCV) infection other than genotype 1 represent a heterogeneous group. The aim of the phase 2 C-SCAPE study was to evaluate elbasvir/grazoprevir (EBR/GZR), with or without ribavirin (RBV), in participants with HCV genotype 2, 4, 5 or 6 infection. This was a part randomised, open-label, parallel-group study (NCT01932762; PN047-03) of treatment-naive, noncirrhotic participants. Participants with HCV genotype 2 infection received GZR 100 mg + RBV ± EBR 50 mg for 12 weeks and those with genotype 4, 5 or 6 infection were randomized to receive EBR/GZR ± RBV for 12 weeks. The primary endpoint was sustained virological response 12 weeks after completion of treatment (SVR12; HCV RNA <25 IU/mL). Among participants with genotype 2 infection, SVR12 was achieved by 80% (24/30) of those receiving EBR/GZR + RBV and 73% (19/26) of those receiving GZR + RBV. SVR rates were high in participants with HCV genotype 4 infection receiving EBR/GZR with and without RBV (100% [10/10] and 90% [9/10]; respectively). In contrast, the addition of RBV to EBR/GZR appeared to increase SVR12 in participants with genotype 5 infection (EBR/GZR, 25%; EBR/GZR + RBV 100% [4/4]). In participants with genotype 6 infection, SVR12 was 75% (3/4) in both those receiving EBR/GZR and those receiving EBR/GZR + RBV. The safety profile was similar across treatment arms, with adverse events tending to occur more frequently among participants receiving RBV. In conclusion, these data support the inclusion of participants with genotype 4 or 6 infection in the EBR/GZR phase 3 studies. EBR/GZR ± RBV was unsatisfactory for participants with genotype 2 or 5 infection.

Sofosbuvir and daclatasvir therapy in patients with hepatitis C-related advanced decompensated liver disease (MELD ≥ 15)

BACKGROUND

Antiviral therapy for hepatitis C has the potential to improve liver function in patients with decompensated cirrhosis.

AIMS

To examine the virological response and effect of viral clearance in patients with decompensated hepatitis C cirrhosis all with MELD scores ≥15 following sofosbuvir/daclatasvir ± ribavirin.

METHODS

We prospectively collected data on patients who commenced sofosbuvir/daclatasvir for 24-weeks under the Australian patient supply program (TOSCAR) and analysed outcomes including sustained viral response at 12 weeks (SVR12), death and transplant.

RESULTS

108 patients (M/F, 79/29; median age 56years; Child-Pugh 10; MELD 16; genotype 1/3, 55/47) received sofosbuvir/daclatasvir and two also received ribavirin. On intention-to-treat, the SVR12 rate was 70% (76/108). Seventy-eight patients completed 24-weeks therapy. SVR12 was achieved in 56 of these patients on per-protocol-analysis (76%). SVR12 was 80% in genotype 1 compared to 69% in genotype 3. Thirty patients failed to complete therapy. In patients achieving SVR12, median MELD and Child-Pugh fell from 16(IQR15-17) to 14(12-17) and 10(9-11) to 8(7-9), respectively (P<.001). In those who died, MELD increased from 16 to 23 at death (P=.036). Patients who required transplantation had a significantly higher baseline MELD (20) compared to those patients completing treatment (16) (P=.0010). The odds ratio for transplant in patients with baseline MELD ≥20 was 13.8(95%CI 2.78-69.04).

CONCLUSIONS

SVR12 rates with sofosbuvir/daclatasvir in advanced liver disease are lower than in compensated disease. Although treatment improves MELD and Child-Pugh in most patients, a significant proportion will die or require transplantation. In those with MELD ≥20, it may be better to delay treatment until post-transplant.

Systematic review and meta-analysis: non-invasive detection of non-alcoholic fatty liver disease related fibrosis in the obese

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a significant disease burden in obesity. Liver fibrosis is an important prognostic factor in NAFLD, and detection is vital. The pathophysiological changes of obesity can alter the accuracy of non-invasive NAFLD tests. We aimed to review current evidence for common non-invasive tests for NAFLD-related fibrosis in obesity.

METHODS

We systematically searched for studies assessing the diagnostic accuracy of 11 biomarker panels and elastography techniques for NAFLD-related fibrosis in obesity. Meta-analyses were performed where possible.

RESULTS

Thirty-eight studies were identified assessing the selected tests in obese populations. Simple biomarker panels (e.g. NAFLD fibrosis score) were the most validated. Evidence showed better accuracy of complex biomarker panels (NAFLD fibrosis score: summary receiver operator characteristic [SROC] 0.795-0.813 vs. enhanced liver fibrosis: SROC 0.962); however, these were poorly validated in obesity. Elastography techniques were better studied and had high diagnostic accuracy (transient elastography: SROC 0.859; magnetic resonance elastography: SROC 0.965) but were limited by BMI-dependent failure. Limited evidence was found to validate the accuracy of any test in exclusively obese populations.

CONCLUSION

In obese subjects, complex biomarker panels and elastography have been reasonable to good accuracy for NAFLD-related fibrosis; however, these methods have not been well validated. Further study in this high-risk population is needed.

Sofosbuvir and velpatasvir with or without voxilaprevir in direct-acting antiviral-naïve chronic hepatitis C: patient-reported outcomes from POLARIS 2 and 3

BACKGROUND

Chronic hepatitis C infection leads to impairment of patient-reported outcomes (PROs). Treatment with direct-acting antiviral regimens results in short- and long-term improvement of these outcomes.

AIM

To assess PROs in patients treated with a newly developed direct-acting antiviral, a fixed-dose combination of sofosbuvir/velpatasvir (SOF/VEL) with/without voxilaprevir (VOX).

METHODS

The PRO data were collected from participants of POLARIS-2 and POLARIS-3 clinical trials (DAA-naïve, all HCV genotypes). Participants self-administered SF-36v2, FACIT-F, CLDQ-HCV and WPAI:SHP instruments at baseline, during treatment, and in follow-up.

RESULTS

Of 1160 patients, 611 received SOF/VEL/VOX and 549 received SOF/VEL (52.8 ± 11.0 years, 55.9% male, 75.4% treatment-naïve, 33.9% cirrhotic). The sustained viral response at 12 weeks (SVR12) rates were 95%-98%. During treatment, improvements in most PRO scores were significant (all but one P < .01) and ranged from, on average, +2.3 to +15.0 points (on a 0-100 scale) by the end of treatment. These improvements were similar between SOF/VEL/VOX and SOF/VEL arms (all P > .05). After treatment discontinuation, patients treated with both regimens achieved significant and clinically meaningful PRO gains (+2.7 to +16.7 by post-treatment week 12, +3.9 to +20.1 by post-treatment week 24; all but one P < .001). Multivariate analysis showed that depression, anxiety and cirrhosis were the most consistent independent predictors of PRO impairment while no association of PROs with the treatment regimen choice was found (all P > .05).

CONCLUSIONS

The pan-genotypic regimens with SOF/VEL with or without VOX not only have excellent efficacy and safety, but also significantly positively impact patients' experience both during treatment and after achieving sustained virologic response in DAA-naïve patients with HCV.

Real-world effectiveness of ombitasvir/paritaprevir/ritonavir±dasabuvir±ribavirin in patients with hepatitis C virus genotype 1 or 4 infection: A meta-analysis

The direct-acting antiviral regimen of ombitasvir (OBV)/paritaprevir (PTV)/ritonavir (r)±dasabuvir (DSV)±ribavirin (RBV) demonstrated high rates of sustained viral response at post-treatment week 12 (SVR12) in clinical trials for treatment of hepatitis C virus (HCV) genotypes (GT) 1 and 4. To confirm the effectiveness of this regimen in the real world, we conducted meta-analyses of published literature on 30 April 2016. Freeman-Tukey transformation determined the SVR rate within GTs 1a, 1b and 4, as well as specific SVR rates by cirrhosis or prior treatment experience status. Rates of virologic relapse, hepatic decompensation, drug discontinuation and serious adverse events were also analysed. In total, 20 cohorts across 12 countries were identified, totalling 5158 patients. The overall SVR12 rates were 96.8% (95% CI 95.8-97.7) for GT1 and 98.9% (95% CI 94.2-100) for GT4. For GT1a patients, the SVR rates were 94% and 97% for those with or without cirrhosis, and 94% overall. For GT1b patients, the SVR rates were 98% and 99% for those with or without cirrhosis, and 98% overall. The virologic relapse rate of GT1 patients was 1.3%, across 3524 patients in nine studies that reported this parameter. The rate of hepatic decompensation was less than 1% across five studies, including 3440 patients, 70% of which had cirrhosis.

CONCLUSIONS

Real-world SVR12 rates for OBV/PTV/r±DSV±RBV were consistently high across HCV GT1 and four irrespective of cirrhosis status or prior HCV treatment experience, confirming effectiveness within a diverse patient population across multiple cohorts and countries.

Impact of viral hepatitis aetiology on survival outcomes in hepatocellular carcinoma: A large multicentre cohort study

While HBV and HCV are risk factors for HCC, uncertainty exists as to whether these viral infections have prognostic significance in HCC. Thus, we compared the overall survival of patients with HBV, HCV and nonviral HCC, and evaluated whether the presence of HBV and HCV predicts patient outcomes. We conducted a multicentre study of HCC cases diagnosed at six Melbourne tertiary hospitals between Jan 2000-Dec 2014. Patient demographics, liver disease and tumour characteristics and patient outcomes were obtained from hospital databases, computer records and the Victorian Death Registry. Survival outcomes were compared between HBV, HCV and nonviral hepatitis cases and predictors of survival determined using Cox proportional hazards regression. There were 1436 new HCC cases identified including 776 due to viral hepatitis (HBV 235, HCV 511, HBV-HCV 30) and 660 from nonviral causes. The median survival of HBV, HCV and nonviral HCC patients was 59.1, 28.4 and 20.9 months, respectively (P<.0001). On multivariate analysis, independent risk factors for survival included HCC aetiology, gender, BCLC stage, serum AFP, total number and size of lesions, and serum creatinine and albumin. After adjusting for these and method of detection, HBV remained an independent predictor of improved overall survival when compared to both nonviral (HR 0.60%, 95% CI 0.35-0.98; P=.03) and HCV-related HCC (HR 0.51%, 95% CI 0.30-0.85; P=.01). In this large multicentre study, HBV is independently associated with improved overall survival compared with HCV and nonviral-related HCC. Further studies are needed to determine the underlying factor(s) responsible.

Systematic review: current concepts and challenges for the direct-acting antiviral era in hepatitis C cirrhosis

BACKGROUND

The burden of HCV cirrhosis is high and projected to increase significantly over the next decade. While interferon therapy is problematic in HCV cirrhosis, the era of direct-acting anti-viral (DAA) therapy provides effective treatment for patients with cirrhosis.

AIM

To systematically review the results of DAA therapy to date in patients with HCV cirrhosis, and highlight the ongoing challenges for DAA therapy in this population.

METHODS

A structured Medline search was conducted to obtain phase II and III HCV trials in patients with cirrhosis. Citations from review articles were cross-referenced and conference abstracts from EASL and AASLD liver meetings for the preceding 3 years were reviewed manually. Keywords used included hepatitis C, cirrhosis and the DAA's: sofosbuvir, ledipasvir, velpatasvir, grazoprevir, elbasvir, daclatasvir, beclabuvir, asunaprevir, simeprevir, paritaprevir, ombitasvir and dasabuvir.

RESULTS

Successful direct-acting anti-viral treatment is now possible in patients with HCV-related cirrhosis including those with liver decompensation with several regimens now offering sustained virological response (SVR) of 90-95%. Overall success rates in GT1 cirrhosis are excellent while GT3-infected patients with cirrhosis remain hard to cure. The pangenotypic combination of sofosbuvir and velpatasvir holds promise for GT3 cirrhosis achieving SVR of ~90%.

CONCLUSIONS

Potent DAA therapies provide much needed, safe and highly effective treatment options for persons with HCV cirrhosis including those previously deemed unsuitable for treatment. Combination therapy with two or more classes of drug is essential to achieve high efficacy and minimise viral resistance, with the role of ribavirin still under evaluation. However, several challenges remain including the hard-to-cure groups of GT3 cirrhosis and direct-acting anti-viral failures, and managing drug-drug interactions.

Historical epidemiology of hepatitis C virus (HCV) in selected countries

Chronic infection with hepatitis C virus (HCV) is a leading indicator for liver disease. New treatment options are becoming available, and there is a need to characterize the epidemiology and disease burden of HCV. Data for prevalence, viremia, genotype, diagnosis and treatment were obtained through literature searches and expert consensus for 16 countries. For some countries, data from centralized registries were used to estimate diagnosis and treatment rates. Data for the number of liver transplants and the proportion attributable to HCV were obtained from centralized databases. Viremic prevalence estimates varied widely between countries, ranging from 0.3% in Austria, England and Germany to 8.5% in Egypt. The largest viremic populations were in Egypt, with 6,358,000 cases in 2008 and Brazil with 2,106,000 cases in 2007. The age distribution of cases differed between countries. In most countries, prevalence rates were higher among males, reflecting higher rates of injection drug use. Diagnosis, treatment and transplant levels also differed considerably between countries. Reliable estimates characterizing HCV-infected populations are critical for addressing HCV-related morbidity and mortality. There is a need to quantify the burden of chronic HCV infection at the national level.

The present and future disease burden of hepatitis C virus (HCV) infection with today's treatment paradigm

The disease burden of hepatitis C virus (HCV) is expected to increase as the infected population ages. A modelling approach was used to estimate the total number of viremic infections, diagnosed, treated and new infections in 2013. In addition, the model was used to estimate the change in the total number of HCV infections, the disease progression and mortality in 2013-2030. Finally, expert panel consensus was used to capture current treatment practices in each country. Using today's treatment paradigm, the total number of HCV infections is projected to decline or remain flat in all countries studied. However, in the same time period, the number of individuals with late-stage liver disease is projected to increase. This study concluded that the current treatment rate and efficacy are not sufficient to manage the disease burden of HCV. Thus, alternative strategies are required to keep the number of HCV individuals with advanced liver disease and liver-related deaths from increasing.

Strategies to manage hepatitis C virus (HCV) disease burden

The number of hepatitis C virus (HCV) infections is projected to decline while those with advanced liver disease will increase. A modeling approach was used to forecast two treatment scenarios: (i) the impact of increased treatment efficacy while keeping the number of treated patients constant and (ii) increasing efficacy and treatment rate. This analysis suggests that successful diagnosis and treatment of a small proportion of patients can contribute significantly to the reduction of disease burden in the countries studied. The largest reduction in HCV-related morbidity and mortality occurs when increased treatment is combined with higher efficacy therapies, generally in combination with increased diagnosis. With a treatment rate of approximately 10%, this analysis suggests it is possible to achieve elimination of HCV (defined as a >90% decline in total infections by 2030). However, for most countries presented, this will require a 3-5 fold increase in diagnosis and/or treatment. Thus, building the public health and clinical provider capacity for improved diagnosis and treatment will be critical.

Hepatic TLR2 & TLR4 expression correlates with hepatic inflammation and TNF-α in HCV & HCV/HIV infection

Signalling activated by Toll-like receptors (TLRs) can result in the production of tumour necrosis factor alpha (TNF-α) which is implicated in hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infection. No study has examined or compared hepatic expression of TLRs in both HCV and HCV/HIV. Liver and peripheral blood mononuclear cells (PBMCs) were obtained from HCV & HCV/HIV-infected patients and PBMCs from HIV-infected patients. Liver RNA was analysed by microarray and reverse transcription quantitative PCR (RT-qPCR). PBMCs were analysed by flow cytometry. Associations with hepatic histology and infection type were sought. Forty-six HCV, 20 HIV and 27 HCV/HIV-infected patients were recruited. Increasing Metavir inflammatory activity score was associated with increased hepatic TLR mRNA by RT-qPCR: TLR2 (P ≤ 0.001), TLR4 (P = 0.008) and TNF-α (P ≤ 0.001). A high degree of correlation was seen between hepatic mRNA expression of TNF-αvs TLR2 (r(2) = 0.66, P < 0.0001) and TLR4 (r(2) = 0.60, P < 0.0001). No differences in TLR gene or protein expression was observed between HCV, HCV/HIV- or HIV-infected groups. Hepatic TLR2, TLR4 and TNF-α mRNA are associated with hepatic inflammation in both HCV and HCV/HIV infection. High correlation between TNF-α and TLR2/TLR4 suggests a role for the innate immune response in TNF-α production. Activation of the innate immune response appears to be independent of infection type.

Tenofovir disoproxil fumarate rescue therapy following failure of both lamivudine and adefovir dipivoxil in chronic hepatitis B

OBJECTIVE

To determine the efficacy of tenofovir disoproxil fumarate (TDF) in adults with chronic hepatitis B virus (HBV) infection who had previously failed lamivudine (LAM) and had significant viral replication (HBV DNA >10⁵ copies/ml if HBeAg positive, > 10⁴ copies/ml if HBeAg negative) despite at least 24 weeks of treatment with adefovir dipivoxil (ADV).

DESIGN

A prospective open-label study of TDF 300 mg daily. Patients receiving combination ADV/LAM prior to baseline were switched to TDF/LAM.

SETTING

Multiple tertiary referral centres.

METHODS

Sixty patients were enrolled. The median age was 48.5 years (range 21e80), 46 (77%) were male and 40 (67%) were HBeAg positive. Thirty-eight patients (63%) were switched from ADV to TDF, the remainder from ADV/LAM to TDF/LAM. At baseline, substitutions conferring resistance to LAM or ADV were present in 20 patients (33%) and 17 patients (28%), respectively. The median baseline viral load was 5.33 log₁₀ IU/ml (range 2.81-8.04). Patients initially treated with TDF monotherapy with persistent viral replication at or after 24 weeks were switched to TDF/LAM. The main outcome measures were change in HBV viral load from baseline and percentage of patients achieving an undetectable viral load (<15 IU/ml).

RESULTS

Results are reported at 96 weeks of treatment. One patient discontinued TDF at 10 days due to rash. The time-weighted change in viral load from baseline to week 12 was -2.19 log10 IU/ml overall. The median change in HBV DNA from baseline to weeks 12, 24, 48 and 96 was -2.86, -3.23, -3.75 and -4.03 log₁₀ IU/ml, respectively. At 48 and 96 weeks, 27/59 (46%) and 38/59 (64%) patients achieved a HBV DNA <15 IU/ml. The response was independent of baseline LAM therapy or mutations conferring ADV resistance.

CONCLUSIONS

In heavily pretreated patients with a high rate of genotypic resistance, TDF retains significant activity against HBV although this appears diminished in comparison with studies of naïve patients.

Tenofovir disoproxil fumarate rescue therapy following failure of both lamivudine and adefovir dipivoxil in chronic hepatitis B

OBJECTIVE

To determine the efficacy of tenofovir disoproxil fumarate (TDF) in adults with chronic hepatitis B virus (HBV) infection who had previously failed lamivudine (LAM) and had significant viral replication (HBV DNA >10⁵ copies/ml if HBeAg positive, > 10⁴ copies/ml if HBeAg negative) despite at least 24 weeks of treatment with adefovir dipivoxil (ADV).

DESIGN

A prospective open-label study of TDF 300 mg daily. Patients receiving combination ADV/LAM prior to baseline were switched to TDF/LAM.

SETTING

Multiple tertiary referral centres.

METHODS

Sixty patients were enrolled. The median age was 48.5 years (range 21e80), 46 (77%) were male and 40 (67%) were HBeAg positive. Thirty-eight patients (63%) were switched from ADV to TDF, the remainder from ADV/LAM to TDF/LAM. At baseline, substitutions conferring resistance to LAM or ADV were present in 20 patients (33%) and 17 patients (28%), respectively. The median baseline viral load was 5.33 log₁₀ IU/ml (range 2.81-8.04). Patients initially treated with TDF monotherapy with persistent viral replication at or after 24 weeks were switched to TDF/LAM. The main outcome measures were change in HBV viral load from baseline and percentage of patients achieving an undetectable viral load (<15 IU/ml).

RESULTS

Results are reported at 96 weeks of treatment. One patient discontinued TDF at 10 days due to rash. The time-weighted change in viral load from baseline to week 12 was -2.19 log10 IU/ml overall. The median change in HBV DNA from baseline to weeks 12, 24, 48 and 96 was -2.86, -3.23, -3.75 and -4.03 log₁₀ IU/ml, respectively. At 48 and 96 weeks, 27/59 (46%) and 38/59 (64%) patients achieved a HBV DNA <15 IU/ml. The response was independent of baseline LAM therapy or mutations conferring ADV resistance.

CONCLUSIONS

In heavily pretreated patients with a high rate of genotypic resistance, TDF retains significant activity against HBV although this appears diminished in comparison with studies of naïve patients.

Influence of endogenous angiotensin II on control of sympathetic nerve activity in human dehydration

Arterial blood pressure can often fall too low during dehydration, leading to an increased incidence of orthostatic hypotension and syncope. Systemic sympathoexcitation and increases in volume regulatory hormones such as angiotensin II (AngII) may help to maintain arterial pressure in the face of decreased plasma volume. Our goals in the present study were to quantify muscle sympathetic nerve activity (MSNA) during dehydration (DEH), and to test the hypothesis that endogenous increases in AngII in DEH have a mechanistic role in DEH-associated sympathoexcitation. We studied 17 subjects on two separate study days: DEH induced by 24 h fluid restriction and a euhydrated (EUH) control day. MSNA was measured by microneurography at the peroneal nerve, and arterial blood pressure, electrocardiogram, and central venous pressure were also recorded continuously. Sequential nitroprusside and phenylephrine (modified Oxford test) were used to evaluate baroreflex control of MSNA. Losartan (angiotensin type 1 receptor (AT1) antagonist) was then administered and measurements were repeated. MSNA was elevated during DEH (42 +/- 5 vs. EUH: 32 +/- 4 bursts per 100 heartbeats, P = 0.02). Blockade of AT1 receptors partially reversed this change in MSNA during DEH while having no effect in the control EUH condition. The sensitivity of baroreflex control of MSNA was unchanged during DEH compared to EUH. We conclude that endogenous increases in AngII during DEH contribute to DEH-associated sympathoexcitation.

Eu(III), Sm(III), Np(V), Pu(V), and Pu(IV) sorption to calcite

The sorption behavior of Eu(III), Sm(III), Np(V), Pu(V), and Pu(IV) in the presence of calcite and as a function of pH and carbonate alkalinity was measured by batch sorption experiments. Eu(III) and Sm(III) sorption is similar, consistent with their observed aqueous speciation and precipitation behavior. For both rare earth elements, sorption decreases at the highest and lowest measured pHs. This is likely the result of speciation changes both of the calcite surface and the sorber. An increase in the equilibrium CO2(g) fugacity results in a shift in the sorption behavior to lower pH, consistent with a predicted aqueous speciation shift. Np(V) and Pu(V) sorption exhibited a strong pH dependence. For Np(V), K ds range from 0 to 217 mL/g suggesting that carbonate aqueous speciation as well as changes in the calcite surface speciation greatly affect Np(V) sorption to the calcite surface. Similar behavior was found for Pu(V). Pu(IV) sorption is also strongly pH dependent. Sorption decreases significantly at high pH as a result of Pu-carbonate complexation in solution. A surface complexation model of Sm(III), Eu(III), Np(V), Pu(V), and Pu(IV) sorption to the calcite surface was developed based on the calcite surface speciation model of Pokrovsky and Schott [1]. Sorption data were fit using one or two surface species for each sorber and could account for the effect of pH and CO2(g) fugacity on sorption. A relatively poor model fit to Pu(IV) sorption data at high pH may result from our poor understanding of Pu(IV)-carbonate aqueous speciation. While our surface complexation model may not represent a unique solution to the sorption data, it illustrates that a surface complexation modeling approach may adequately describe the sorption behavior of a number of radionuclides at the calcite surface over a range of solution conditions.

Aqueous dissolution kinetics of pyrochlore, zirconolite and brannerite at 25, 50, and 75 °C

We measured the rates of dissolution of pyrochlore, zirconolite, and brannerite in pH-buffered solutions of pH 2, 4, 6, 8, 10, and 12 at temperatures of 25, 50, and 75 °C in flow-through reactors. The dissolution rates for all phases show a minimum near pH 8. Zirconolite dissolves the slowest of the three phases, with a slightly higher rate for pyrochlore and a much higher dissolution rate for brannerite. Brannerite dissolves as much has 30 times faster than zirconolite. The rates increase with temperature, but the magnitude of the increase varies with pH. The calculated average apparent activation energy for dissolution is 6±3 kcal/mole. Dissolution is non-stoichiometric at all pHs. Ti and Hf are released most slowly, and are often below detection limits (1 ppb for Ti, 0.2 ppb for Hf). Releases of Ca, U, Gd, and Ce appear to be stoichiometric below pH 8. At pH 8 and above only U is measurable in solution. Dissolution rates are slow under all conditions, and commonly in the range of 1-100 nm total dissolution/year (between 10-3.5 and 10-5.5 g/m2/day).

Simultaneous widefield single molecule orientation and FRET microscopy in cells

We combine single molecule fluorescence orientation imaging with single-pair fluorescence resonance energy transfer microscopy, using a total internal reflection microscope. We show how angles and FRET efficiencies can be determined for membrane proteins at the single molecule level and provide data from the epidermal growth factor receptor system in cells.

Human dendritic cells pulsed with specific lipopeptides stimulate autologous antigen-specific T cells without the addition of exogenous maturation factors

Serum-free culture conditions to generate immature human monocyte-derived DC (Mo-DC) were optimized, and the parameters that influence their maturation after exposure to lipopeptides containing CD4(+) and CD8(+) T-cell epitopes were examined. The lipopeptides contained a single CD4(+) helper T-cell epitopes, one of a number of human leucocyte antigen (HLA)-A2-restricted cytotoxic T-cell epitope and the lipid Pam2Cys. To ensure complete maturation of the Mo-DC, we examined (i) the optimal lipopeptide concentration, (ii) the optimal Mo-DC density and (iii) the appropriate period of exposure of the Mo-DC to the lipopeptides. The results showed that a high dose of lipopeptide (30 microm) was no more efficient at upregulating maturation markers on Mo-DC than a low dose (6 microm). There was an inverse relationship between Mo-DC concentration and the mean fluorescence intensity of maturation markers. In addition, at the higher cell concentrations, the chemotactic capacity of the Mo-DC towards a cognate ligand, CCL21, was reduced. Thus, high cell concentrations during lipopeptide exposure were detrimental to Mo-DC maturation and function. The duration of exposure of Mo-DC to the lipopeptides had little effect on phenotype, although Mo-DC exposed to lipopeptides for 48 rather than 4 h showed an increased ability to stimulate autologous peripheral blood mononuclear cells to release interferon-gamma in the absence of exogenous maturation factors. These findings reveal conditions for generating mature antigen-loaded DC suitable for targeted immunotherapy.

Review article: management of patients with chronic hepatitis C virus infection and "normal" alanine aminotransferase activity

BACKGROUND

Hepatitis C virus infection, a major cause of chronic liver disease, occurs with normal serum alanine aminotransferase activity in approximately 25% of patients. These patients have historically remained untreated but substantial evidence indicates liver damage, progression of disease and impaired quality of life in some individuals.

AIM

To review the current management of patients with chronic hepatitis C and normal alanine aminotransferase activity.

METHODS

This review represents the summary of discussions at a Clinical Workshop with a comprehensive literature searching of available databases (PubMed and Embase).

RESULTS

Current limits defining normal serum alanine aminotransferase activity are not representative of a "healthy" status. Most patients with hepatitis C and normal alanine aminotransferase levels have histologically proven liver damage that, although generally mild, may be significant (> or =F2) in up to 20% of patients and progresses at approximately 50% of the rate in patients with elevated alanine aminotransferase levels. Some patients have persistently normal alanine aminotransferase activity and may have a more benign outcome, but a significant proportion (> or =20%) experience periods of increased serum alanine aminotransferase activity which may be associated with enhanced disease progression.

CONCLUSIONS

A treatment approach that considers host and virus-related variables and optimizes patient and cost benefits may therefore provide more effective management of patients with chronic hepatitis C and normal alanine aminotransferase activity.

Multidimensional single-molecule imaging in live cells using total-internal-reflection fluorescence microscopy

We have developed a wide-field total-internal-reflection fluorescence microscope capable of imaging single molecules in live cells, resolved in both wavelength and polarization. We show fluorescence resonance energy transfer between single pairs of fluorescent molecules bound to signaling receptors in the plasma membrane of live cells and demonstrate the importance of polarization discrimination in addition to wavelength separation.

Sustained virological response rates and durability of the response to interferon-based therapies in hepatitis C patients treated in the clinical setting

International controlled trials have demonstrated increasing sustained virological response (SVR) rates to interferon-based therapies in hepatitis-C-treated patients. Response rates of 6-20% in the era of interferon monotherapy are compared with 42-82% with pegylated interferon plus ribavirin. The virological durability of the SVR is unknown and the optimal follow-up for these patients is unclear. The aim of our study was to determine SVR rates and the durability of the response to interferon-based therapies in the clinical setting. From our database of 1540 hepatitis C patients, 344 treatment courses of at least 12 weeks duration were identified, including interferon monotherapy (175 patients), interferon plus ribavirin (96 patients) and peginterferon plus ribavirin (73 patients). Interferon monotherapy was associated with an SVR rate of 5% in 103 genotype 1 patients and 25% in 72 genotype 2/3 patients. Response rates were higher (P < 0.001) with interferon plus ribavirin-41% in 34 genotype 1 patients and 73% in 62 genotype 2/3 patients-and with peginterferon plus ribavirin-47% in 47 genotype 1 patients and 79% in 26 genotype 2/3 patients. Of 147 patients with an SVR, 146 (>99%) remained hepatitis C virus PCR negative during a mean 2.3 years (range 0.3-10.3) of follow-up. In conclusion, with advances in therapies, we are achieving higher response rates in hepatitis C patients treated in the clinical setting. We can now expect an SVR in over half of the treated patients. Importantly, the response is durable and medium and long-term follow-up of these patients are of low yield and largely unnecessary.

Interactions of plasma osmolality with arterial and central venous pressures in control of sympathetic activity and heart rate in humans

Plasma osmolality alters control of sympathetic activity and heart rate in animal models; however, it is unknown whether physiological increases in plasma osmolality have such influences in humans and what effect concurrent changes in central venous and/or arterial pressures may have. We tested whether physiological increases in plasma osmolality (similar to those during exercise dehydration) alter control of muscle sympathetic nerve activity (MSNA) and heart rate (HR) in humans. We studied 17 healthy young adults (7 women, 10 men) at baseline and during arterial pressure (AP) transients induced by sequential injections of nitroprusside and phenylephrine, under three conditions: control (C), after 1 ml/kg intravenous hypertonic saline (HT1), and after 2 ml/kg hypertonic saline (HT2). We continuously measured HR, AP, central venous pressure (CVP; peripherally inserted central catheter) and MSNA (peroneal microneurography) in all conditions. Plasma osmolality increased from 287 +/- 1 mosmol/kg in C to 290 +/- 1 mosmol/kg in HT1 (P < 0.05) but did not increase further in HT2 (291 +/- 1 mosmol/kg; P > 0.05 vs. C). Mean AP and CVP were similar between C and HT1, but both increased slightly in HT2. HR increased slightly but significantly during both HT1 and HT2 vs. C (P < 0.05). Sensitivity of baroreflex control of MSNA was significantly increased vs. C in HT1 [-7.59 +/- 0.97 (HT1) vs. -5.85 +/- 0.63 (C) arbitrary units (au).beat(-1).mmHg(-1); P < 0.01] but was not different in HT2 (-6.55 +/- 0.94 au.beat(-1).mmHg(-1)). We conclude that physiological changes in plasma osmolality significantly alter control of MSNA and HR in humans, and that this influence can be modified by CVP and AP.

Exercise-related abdominal pain as a manifestation of the median arcuate ligament syndrome

Abdominal pain related to exercise, often loosely referred to as 'stitch', is not uncommon, particularly among participants in sports that involve running. The cause of this typically transient pain is poorly understood with several aetiologies proposed including diaphragmatic ischaemia (1, 2). Other gastrointestinal symptoms that are common during prolonged or high-intensity exercise include nausea, diarrhoea and gastrointestinal bleeding (3, 4). These symptoms are also usually transient and are thought to protect against critical organ damage by promoting cessation of exercise. Decreased gastrointestinal blood flow, increased motility and altered neuroendocrine modulation are postulated disease mechanisms (3). We report here a case of an elite runner with exercise-related severe abdominal pain and diarrhoea related to compression of the coeliac axis by the median arcuate ligament. Complete symptom relief was achieved with surgical division of the constricting ligament. The clinical characteristics and pathogenesis of coeliac axis compression syndrome are discussed.

Eicosanoid involvement in the regulation of behavioral fever in the desert locust, Schistocerca gregaria

The desert locust Schistocerca gregaria behaviorally thermoregulates in order to try and maintain a favoured "set point" body temperature. Locusts infected with the deuteromycete fungal pathogen Metarhizium anisopliae var acridumchoose a significantly elevated temperature. This "behavioral fever" greatly delays the progress of mycosis. We have confirmed this phenomenon and shown that desert locusts also fever when infected with the bacterial pathogen Serratia marcescens. Elevation in the prefered environmental temperature occurs also upon injection with laminarin and lipopolysaccharide (microbial cell wall components). Since such treatments also stimulate the immune system it would appear that "behavioral fever" is probably a feature of the immune response. The eicosanoid biosynthesis inhibitor dexamethasone prevented laminarin invoked fever. This effect was reversable by arachidonic acid. Therefore in common with the febrile response in mammals behavioral fever in insects may be mediated locally by circulating eicosanoids.

Evaluating biofilm growth of two oral pathogens

AIMS

To determine the expediency of a microtitre assay system for establishing, quantifying and antimicrobial testing of two representative oral pathogens.

METHODS AND RESULTS

Streptococcus mutans and Porphyromonas gingivalis were used. Morphological characteristics of the attached population were evaluated. Biofilm growth was evaluated spectrophotometrically (undisturbed and 1 N NaOH dissipated biofilm). The minimum concentration of chlorhexidine gluconate that inhibited biofilm growth was determined. Growth of the biofilms was successfully monitored by direct optical density measurements or those re-suspended in 1 N NaOH. The latter was necessary when glucans were present in Strep. mutans biofilms. The minimum concentration of chlorhexidine gluconate that inhibited biofilm growth was 1.25 microg ml(-1) for both species. The attached bacteria exhibited common biofilm characteristics.

SIGNIFICANCE AND IMPACT OF THE STUDY

The assay system developed was especially useful for monitoring the growth of adherent Strep. mutans in the presence of glucans, which is particularly significant for the study of anti-plaque chemicals.

Recurrent autoimmune hepatitis after orthotopic liver transplantation

To determine the frequency, risk factors, and consequences of recurrent autoimmune hepatitis after liver transplantation, 41 patients with type 1 disease were monitored after surgery in accordance with a surveillance protocol. Tacrolimus or cyclosporine plus prednisone were administered to each patient, and liver biopsy examinations were performed at least annually according to protocol. Corticosteroid therapy was ultimately discontinued in only 2 patients. Recurrent disease was defined as the presence of lymphoplasmacytic infiltrates in liver tissue in the absence of other causes of allograft dysfunction. Autoimmune hepatitis recurred in 7 patients (17%), and the mean time to recurrence was 4.6 +/- 1 years. Recurrence was asymptomatic in 4 of 7 patients and detected only by surveillance liver biopsy assessment in 2 patients. Histological changes were mild, and there was no progression to cirrhosis during 4.9 +/- 0.9 years of observation. Five-year patient (86% v. 82%; P =.9) and graft (86% v. 67%; P =.5) survival rates were not statistically different between patients with and without recurrent disease. HLA-DR3 or HLA-DR4 occurred more commonly in patients with than without recurrence (100% v. 40%; P =.008) and healthy subjects (100% v. 49%; P =.01). Recurrent disease was unrelated to donor HLA status. In conclusion, recurrence after transplantation for type 1 autoimmune hepatitis is common. Its mild manifestations and favorable prognosis may reflect early detection by a surveillance protocol and/or continuous corticosteroid treatment. HLA-DR3- or HLA-DR4-positive recipients are at risk for recurrence regardless of donor HLA status.

Primary hepatocellular carcinoma in Australia, 1978-1997: increasing incidence and mortality

OBJECTIVES

To describe trends in primary hepatocellular carcinoma (HCC) incidence and mortality in Australia between 1978 and 1997, and to delineate the effects of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection by examining cases of HCC in Australian-born and overseas-born people separately.

DESIGN AND SETTING

Retrospective analysis of national incidence and mortality data in which the underlying cause was coded as HCC (International classification of diseases, ninth revision [ICD-9] code 155.0).

MAIN OUTCOME MEASURES

Changes in age-standardised HCC incidence rates in men and women between 1983 and 1996; age-standardised HCC death rates in Australian-born and overseas-born men and women between 1978 and 1997.

RESULTS

Age-standardised incidence rates increased in men and women (from 2.06 and 0.57 per 100,000 respectively in 1983-1985 to 3.97 and 0.99 respectively in 1995-1996). Age-standardised death rates increased in Australian-born and overseas-born men and overseas-born women (from 1.43, 2.35 and 0.62 respectively per 100,000 in 1978-1982 to 2.50, 4.41 and 1.36 respectively in 1993-1997). However, death rates in Australian-born women did not increase (0.58 per 100,000 in 1978-1982 and 0.63 in 1993-1997).

CONCLUSIONS

HCC incidence and death rates in Australia have increased over the past two decades, except in Australian-born women. A likely explanation for at least a portion of this increase is increased prevalences of HBV and HCV infection in Australia.

The effects of ABA on channel-mediated K(+) transport across higher plant roots

The transport and accumulation of K(+) in higher plant roots is regulated by ABA. Molecular and electrophysiological techniques have identified a number of discrete transporters which are involved in the translocation of K(+) from the soil solution to the shoots of higher plants. Furthermore, recent reports have shown that ABA regulates K(+) channel activity in maize and Arabidopsis roots which suggests that ABA regulation of K(+) transport in roots is, at least in part, ion channel-mediated. The signalling processes which underlie the ABA regulation of K(+) channels have been investigated. The effects of ABA on the membrane potential of intact maize root cells were also studied. It was found that ABA regulated the membrane potential of root cells and that this regulation is consistent with the hypothesis that ABA-induced K(+) accumulation in roots is mediated by K(+) channels.

Risk factor assessment for the acquisition of fluoroquinolone-resistant isolates of Pseudomonas aeruginosa in a community-based hospital

A case-control study was performed in a community-based nonteaching hospital to assess patient risk factors for the acquisition of fluoroquinolone-resistant isolates of Pseudomonas aeruginosa. Fifty-five patients who were hospitalized between July 1, 1993 and December 31, 1993 and who had P. aeruginosa recovered from a clinical specimen were included in the analysis. Two patient populations were designated based on the fluoroquinolone susceptibility of their P. aeruginosa isolates. Statistical evaluation using univariate analysis of demographic and clinical data from the 42 patients with quinolone-susceptible P. aeruginosa and the 13 patients with quinolone-resistant P. aeruginosa demonstrated that prior receipt of a fluoroquinolone was the only significant risk factor for the subsequent emergence of fluoroquinolone resistance among P. aeruginosa isolated from patients hospitalized in this small community-based institution (p = 0.0196). Multivariate analysis supported the finding that prior receipt of a fluoroquinolone was the major risk factor for the isolation of fluoroquinolone-resistant P. aeruginosa (p = 0.0004); isolation of this Gram-negative bacillus from sputum (p = 0.0306) and a history of recent surgery (p = 0.0058) were also significantly associated as risk factors for resistance.

Divalent cation block of inward currents and low-affinity K+ uptake in Saccharomyces cerevisiae

We have used the patch clamp technique to characterize whole-cell currents in spheroplasts isolated from a trk1Delta trk2Delta strain of Saccharomyces cerevisiae which lacks high- and moderate-affinity K+ uptake capacity. In solutions in which extracellular divalent cation concentrations were 0.1 mM, cells exhibited a large inward current. This current was not the result of increasing leak between the glass pipette and membrane, as there was no effect on the outward current. The inward current comprised both instantaneous and time-dependent components. The magnitude of the inward current increased with increasing extracellular K+ and negative membrane potential but was insensitive to extracellular anions. Replacing extracellular K+ with Rb+, Cs+, or Na+ only slightly modulated the magnitude of the inward current, whereas replacement with Li+ reduced the inward current by approximately 50%, and tetraethylammonium (TEA+) and choline were relatively impermeant. The inward current was blocked by extracellular Ca2+ and Mg2+ with apparent Kis (at -140 mV) of 363 +/- 78 and 96 +/- 14 microM, respectively. Furthermore, decreasing cytosolic K+ increased the magnitude of the inward current independently of the electrochemical driving force for K+ influx, consistent with regulation of the inward current by cytosolic K+. Uptake of 86Rb+ by intact trk1Delta trk2Delta cells was inhibited by extracellular Ca2+ with a Ki within the range observed for the inward current. Furthermore, increasing extracellular Ca2+ from 0.1 to 20 mM significantly inhibited the growth of these cells. These results are consistent with those of the patch clamp experiments in suggesting that low-affinity uptake of alkali cations in yeast is mediated by a transport system sensitive to divalent cations.

Liver transplantation for cryptogenic cirrhosis

End-stage liver disease secondary to cryptogenic cirrhosis is the indication for orthotopic liver transplantation (OLT) in 7% to 14% of recipients. However, there are no reports documenting the outcome of OLT for this indication. The aim of this study was to determine (1) survival and (2) the incidence of histological recurrence of cryptogenic cirrhosis after OLT. Between March 1985 and December 1994, 560 OLTs were performed at our institution. Of these, 39 transplants for cryptogenic cirrhosis were in patients who met the following criteria: antinuclear antibody < 1:40; negative anti-smooth muscle antibody, antimitochondrial antibody, polymerase chain reaction for hepatitis C virus, and hepatitis B surface antigen results; normal ceruloplasmin and alpha-1 antitrypsin phenotype; transferrin saturation < 65%; and liver biopsy specimen not suggestive of hemochromatosis or other known disorders. Histological recurrence was assessed with protocol liver biopsies in all patients who survived longer than 6 months. The mean age of cryptogenic recipients at the time of transplantation was significantly lower (40.6 years; range, 3 to 63 years) than that of noncryptogenic recipients (48.5 years; range, 1-70; P < .03). Median modified Child's-Pugh score was slightly higher for cryptogenic recipients at the time of transplantation (10.0 + 0.08 standard error of mean [SEM]), than for the noncryptogenic recipients (9.0 + 0.03 SEM; P < .02). Actuarial survival was 72% (+ 0.07 SEM) at 1 and 58% (+ 0.08 SEM) at 5 years for cryptogenic recipients compared with 89% at 1 and 80% at 5 years for noncryptogenic recipients. The difference in survival was significant (P < .001) at both 1 and 5 years. Among the 27 cryptogenic recipients surviving more than 6 months (mean follow-up, 5.5 years), 6 have persistent hepatitis histologically without apparent infectious, vascular, biliary, or drug origins. Four patients (15%) had chronic active hepatitis, and 2 (7%) had steatohepatitis. No cases of recurrent cryptogenic cirrhosis were seen. OLT for cryptogenic cirrhosis is associated with a poor outcome compared with other indications, hepatitis of uncertain origin occurred in 22% of cryptogenic recipients surviving longer than 6 months, and no evidence of recurrence of cryptogenic cirrhosis was seen thus far in follow-up.

Management of haematemesis and melaena

Upper gastrointestinal bleeding remains a common medical emergency with high morbidity and mortality. High risk patients are best managed in specialised units. Endoscopy is the procedure of choice for diagnosis and haemostatic therapy of peptic ulcers, reducing deaths and the probability of rebleeding, as well as the need for surgery; for acute variceal bleeding, pharmacotherapy followed by endoscopic ligation is recommended.

A patch clamp study of Na+ transport in maize roots

The mechanisms mediating Na(+) transpdrt in higher plant roots were investigated by applying the patch clamp technique to protoplasts isolated from the cortex and stele of maize roots. In the cortex, permeation of Na+ through a time-dependent K(+)-selective inward rectifier was negligible. Instead, Na(+) influx into maize roots probably occurs via an instantaneously-activating current. This current was partially inhibited by extracellular Ca(2+), but was insensitive to extracellular TEA(+), Cs(+) and TTX. In outside-out patches, a plasma membrane ion channel was found which mediated an inward Na(+) current which, at least in part, underlies the whole-cell instantaneously-activating current. The unitary conductance of this channel was 15 pS in 102:121 mM Na(+) (outsidexytosol). Channel gating was voltage-independent and distinct from that observed for the inwardly rectifying K(+)-selective channel in the same cell type. Increasing extracellular Ca(2+) from 0.1 to 1 mM reduced the open probability and unitary conductance of this channel. In 102 mM Na(+) : 123 mM K(+) (outside:cytosol) a P(Na):P(K) of 2.1 was calculated. It is suggested that the plasma membrane Na(+)-permeable channel identified in the cortex of maize roots represents a pathway for low affinity Na(+) uptake by intact maize roots. In the stele, permeation of Na(+) through outwardly rectifying K(+) channels was found to be negligible and the channels are thus unlikely to be involved in the transport of Na(+) from the root symplasm.

The pathobiology of biliary epithelia

Our understanding of the pathobiology of biliary epithelia is rapidly growing because of a surge of investigative activity. This became possible after suitable experimental models and techniques were developed with which to study cholangiocyte biology. Although the molecular mechanisms of bile formation by cholangiocytes and the role of these cells as a major cellular target in a variety of severe hepatobiliary diseases are currently being investigated, many questions remain unanswered, particularly regarding cholangiocellular functions, both in normal and abnormal conditions. As current experimental models become more refined, scientists with interests as diverse as cell biology and physiology, morphology, pharmacology, immunology, genetics, and oncology can be expected to further clarify the pathobiology of biliary epithelia.

Rat hepatocytes transport water mainly via a non-channel-mediated pathway

During bile formation by the liver, large volumes of water are transported across two epithelial barriers consisting of hepatocytes and cholangiocytes (i.e. intrahepatic bile duct epithelial cells). We recently reported that a water channel, aquaporin-channel-forming integral protein of 28 kDa, is present in cholangiocytes and suggested that it plays a major role in water transport by these cells. Since the mechanisms of water transport across hepatocytes remain obscure, we performed physiological, molecular, and biochemical studies on hepatocytes to determine if they also contain water channels. Water permeability was studied by exposing isolated rat hepatocytes to buffers of different osmolarity and measuring cell volume by quantitative phase contrast, fluorescence and laser scanning confocal microscopy. Using this method, hepatocytes exposed to hypotonic buffers at 23 degrees C increased their cell volume in a time and osmolarity-dependent manner with an osmotic water permeability coefficient of 66.4 x 10(-4) cm/s. In studies done at 10 degrees C, the osmotic water permeability coefficient decreased by 55% (p < 0.001, at 23 degrees C; t test). The derived activation energy from these studies was 12.8 kcal/mol. After incubation of hepatocytes with amphotericin B at 10 degrees C, the osmotic water permeability coefficient increased by 198% (p < 0.001) and the activation energy value decreased to 3.6 kcal/mol, consistent with the insertion of artificial water channels into the hepatocyte plasma membrane. Reverse transcriptase polymerase chain reaction with hepatocyte RNA as template did not produce cDNAs for three of the known water channels. Both the cholesterol content and the cholesterol/phospholipid ratio of hepatocyte plasma membranes were significantly (p < 0.005) less than those of cholangiocytes; membrane fluidity of hepatocytes estimated by measuring steady-state anisotropy was higher than that of cholangiocytes. Our data suggests that the osmotic flow of water across hepatocyte membranes occurs mainly by diffusion via the lipid bilayer (not by permeation through water channels as in cholangiocytes).

Prognosis of histological cirrhosis in type 1 autoimmune hepatitis

BACKGROUND & AIMS

Cirrhosis connotes irreversible damage to the liver and shortened life expectancy. The aim of this study was to evaluate the impact of cirrhosis on treatment response and survival in type 1 autoimmune hepatitis.

METHODS

One hundred twenty-eight patients were evaluated for histological cirrhosis. Response to treatment, predictors for cirrhosis, and outcomes were determined.

RESULTS

Thirty-seven patients (29%) had histological cirrhosis at entry, whereas 36 of the 91 patients without cirrhosis (40%) developed it during 39 +/- 32 months. Development of cirrhosis was predicted by lower serum albumin levels (P=0.04) and higher prothrombin times (P<0.001) at presentation. The frequencies of remission, relapse after drug withdrawal, and treatment failure were comparable in patients with and without cirrhosis at entry. The overall 10-year survival (93%) was similar to that of an age-and sex-matched cohort from the population at large (94%). Ten-year survival was not different between those with and those without cirrhosis at entry (89% and 90%, respectively), even with transplantation as an end point.

CONCLUSIONS

Patients with histological cirrhosis at presentation respond to corticosteroid therapy as well as patients without cirrhosis. Low serum albumin levels and hypoprothrombinemia at presentation predict the development of cirrhosis. Histological cirrhosis does not diminish survival expectations.

Cholangiocytes express the aquaporin CHIP and transport water via a channel-mediated mechanism

Cholangiocytes line the intrahepatic bile ducts and regulate salt and water secretion during bile formation, but the mechanism(s) regulating ductal water movement remains obscure. A water-selective channel, the aquaporin CHIP, was recently described in several epithelia, so we tested the hypothesis that osmotic water movement by cholangiocytes is mediated by CHIP. Isolated rodent cholangiocytes showed a rapid increase in volume in the presence of hypotonic extracellular buffers; the ratio of osmotic to diffusional permeability coefficients was > 10. The osmotically induced increase in cholangiocyte volume was inversely proportional to buffer osmolality, independent of temperature, and reversibly blocked by HgCl2. Also, the luminal area of isolated, enclosed bile duct units increased after exposure to hypotonic buffer and was reversibly inhibited by HgCl2. RNase protection assays, anti-CHIP immunoblots, and immunocytochemistry confirmed that CHIP transcript and protein were present in isolated cholangiocytes but not in hepatocytes. These results demonstrate that (i) isolated cholangiocytes and intact, polarized bile duct units manifest rapid, mercury-sensitive increases in cell size and luminal area, respectively, in response to osmotic gradients and (ii) isolated cholangiocytes express aquaporin CHIP at both the mRNA and the protein level. The data implicate aquaporin water channels in the transcellular movement of water across cholangiocytes lining intrahepatic bile ducts and provide a plausible molecular explanation for ductal water secretion.

Cytoplasmic calcium and Fucus egg activation

Eggs of the marine brown alga, Fucus serratus, exhibit small transient elevations of cytosolic Ca2+ of variable magnitude, corresponding to the onset of the fertilization potential. Microinjection of Ca2+ buffers (BAPTA (1-2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid)) at concentrations sufficient to block any global fertilization-associated Ca2+cyt elevation did not inhibit egg activation (monitored as exocytosis of cell wall) or subsequent development. However, egg activation could be inhibited with higher buffer concentrations. Br2BAPTA (Kd = 1.6 micromolar) was a more effective inhibitor of egg activation than BAPTA (Kd = 0.17 micromolar). Localized microinjection of Ca2+ produced only localized cell wall exocytosis at the injection site. Eggs injected with Br2BAPTA at intracellular concentrations, which blocked egg activation, exhibited prolonged fertilization potentials. 45Ca2+ influx across the plasma membrane increased during fertilization. Our results show that a large transient global elevation of Ca2+cyt is not necessary for Fucus egg activation but rather a localized elevation to micromolar levels results, at least in part, from increased Ca2+ influx across the plasma membrane. This is needed for early fertilization events, including the generation of the fertilization potential and cell wall secretion.

THE ROLE OF Ca2+ IN SIGNAL TRANSDUCTION FOLLOWING FERTILIZATION IN FUCUS SERRATUS

The marine brown alga Fucus serratus represents one of the few multicellular plant species in which the process of fertilization can be studied relatively easily. Fertilization marks the onset of a cascade of events associated with egg activation. Fertilization in Fucus serratus bears several superficial similarities to fertilization in several animal systems. The essential features of Fucus serratus egg activation are compared with those of protostome and deuterostome animal systems. Ca2+ is required for egg activation in Fucus serratus and cytosolic [Ca2+] changes can be observed in fertilizing eggs. However, these are small and variable in comparison with those occurring in deuterostomes, and fertilization can proceed normally in the absence of any global cytosolic Ca2+ transients. A model for egg activation in Fucus serratus is presented, invoking a role for both Ca2+ influx and localized propagation of the sperm signal around the plasma membrane by an as yet unidentified mechanism. Polarity in Fucus serratus is acquired a considerable time after fertilization and the role of cytosolic Ca2+ gradients in the acquisition and expression of polarity is discussed. The problem of the signals associated with the onset of the cell cycle in the fertilized Fucus serratus egg is also addressed.

Modulation of uptake of heme by rat small intestinal mucosa in iron deficiency

Although body iron status modulates whole body retention of heme derived iron, it is not known with certainty whether modulation occurs by regulation of mucosal uptake of heme. In vivo uptake from perfused intestine of heme labeled with 14C in the porphyrin ring was studied in groups of rats of differing iron status ranging from fully replete to markedly iron deficient. Heme extraction from infusate and mucosal heme uptake were significantly different between test groups (P < 0.005 and 0.001, respectively). Marked iron deficiency induced a 4.8-fold rise in heme extraction relative to iron-replete animals; rats with latent iron deficiency showed a smaller but still significant rise. Heme extraction correlated negatively with indicators of iron status: hemoglobin (r = -0.76, P < 0.001) and serum iron (r = -0.56, P < 0.05). The specific binding of [14C]heme to purified brush borders from iron-replete and iron-deficient rats was 1.4-fold higher in deficient rats when expressed per milligram of protein (P = 0.046) and 3.3-fold higher when expressed relative to alkaline phosphatase activity (P = 0.014). Thus mucosal uptake of heme in iron deficiency is increased because of an increase in its binding to the brush border.

Regulation of bicarbonate-dependent ductular bile secretion assessed by lumenal micropuncture of isolated rodent intrahepatic bile ducts

While intrahepatic bile duct epithelial cells secrete bile through transport of ions and water, the physiological mechanisms regulating ductular bile secretion are obscure, in part because of the lack of suitable experimental models. We report here the successful micropuncture of the lumen of isolated intrahepatic bile ducts and direct measurements of ductular ion secretion. Intact, polarized bile duct units (BDUs) were isolated from livers of normal rats by enzymatic digestion and microdissection. BDUs were cultured and mounted on a microscope in bicarbonate-containing buffer, and the lumens were microinjected with 2',7'-bis(2-carboxyethyl)-5-(and -6)carboxyfluorescein (BCECF)-dextran. Lumenal pH was measured by ratio imaging of BCECF fluorescence using digitized video fluorescent microscopy. After 36 hr in culture, the ends of BDUs sealed, forming closed compartments. After lumenal microinjection of BCECF-dextran, fluorescence was stable at the pH-insensitive wavelength, indicating no dye leakage. Serial changes in pH of extralumenal buffers containing pH-gradient collapsing ionophores allowed us to establish reliable standard curves relating fluorescence ratio to lumenal pH (r = 0.99; P < 0.001). By this approach, the basal pH inside the lumen of BDUs was 7.87 +/- 0.08 units (n = 9), 0.47 unit higher (P < 0.001) than the bathing buffer pH. Addition of 100 microM forskolin increased (P = 0.02) the lumenal pH from 7.78 +/- 0.06 to 7.97 +/- 0.06 units (n = 5); the forskolin effect was completely abolished by incubation of BDUs in HCO3-/CO2-free buffer. Moreover, forskolin caused a 50-fold increase in cAMP levels in BDUs. The observations are consistent with cAMP-dependent, active lumenal HCO3- secretion by BDUs. Furthermore, they demonstrate the suitability of the BDU model for studying regulatory and mechanistic aspects of ductular bile secretion.

The distribution of ABO and Rh(D) and selected high- and low-frequency antigens in the people in the Kingdom of Tonga

The incidence of red cell A, B, and D antigens in 7903 people from the Kingdom of Tonga is reported. ABO and D typings were performed by the slide method while establishing a registry of potential blood donors. The results of selected high-frequency antigens and one low-frequency antigen typing of 1009 donors also are reported.

Glucose, glycine and diglycine in test meals at stimuli to a duodenal osmoreceptor slowing gastric emptying

1. Five subjects took 210 test meals of 750 ml. water containing 30--300 m-molal glucose or glycine, or 15--150 m-molal diglycine, or plain water. 2. The greater the concentration of solute, the greater was the volume of original meal recovered from the stomach after a fixed time. 3. On a molal basis glucose was half as effective as diglycine in slowing gastric emptying. This was consistent with the osmoreceptor being exposed to the diglycine after it had been split by the hydrolase of the cytosol of enterocytes (the absorbing cells of the small intestine). 4. The slowing of gastric emptying (ml./mole.1.) was about 10% greater for glycine than it was for glucose. There was apparently a threshold concentration below which glycine did not slow gastric emptying. 5. It was proposed that the response of the doudenal osmoreceptor might depend upon shrinking and swelling of the lateral intercellular space around the enterocytes.

Actions of glucose and potassium chloride on osmoreceptors slowing gastric emptying

1. Five subjects were given 373 test meals of 750 ml. water containing a range of concentrations of glucose or potassium chloride.2. The greater the concentration of solute in the meals, the greater was the volume of the test meal recovered from the stomach after a fixed time.3. When the concentrations of the solutes were expressed as m-osmole/l. corrected by osmotic coefficients based on vapour pressures at 37 degrees C, glucose and potassium chloride were indistinguishable in slowing gastric emptying.4. These results are consistent with the regulation of gastric emptying by a duodenal receptor responding to osmotic pressure.5. Potassium chloride was more nauseating than glucose on an osmolar basis.