Differential Prognostic Value of Extrarenal Involvement in Patients With Non-Metastatic Renal Cell Cancer

INTRODUCTION

A better definition of the prognostic significance of non-metastatic pT3a stage RCC subcategories is crucial to select the best candidate for adjuvant treatment. The aim of the study is to investigate the differential prognosis of extrarenal involvement in patients with non-metastatic pT3a RCC.

MATERIALSAND METHODS

From a single institutional prospective database, 451 consecutive patients treated for pT3aN0/NxM0 RCC were selected and stratified according to pT3a subtypes (perirenal fat invasion, sinus fat invasion, segmental/renal vein thrombus, ≥ 2 features). Cancer specific survival (CSS), metastasis free survival (MFS) and relapse free survival (RFS) were primary endpoints of multivariable Cox regression models.

RESULTS

Overall, 67 (15%) patients presented with renal/segmental vein thrombus only, 185 (41%) with perirenal fat invasion, 101 (22%) with sinus fat invasion and 98 (22%) with ≥ 2 features. The presence of ≥ 2 pT3a features was associated with a higher risk of metastasis (HR=2.36; 95%CI 1.30-4.27; P value = .005), recurrence (HR=2.41; 95%CI 1.36-4.28; P value=.003) and cancer specific mortality (HR=3.54; 95%CI 1.45-8.63; P value = .005) compared to only 1 pT3a feature. Moreover, the presence of perirenal fat invasion was associated with lower CSS (HR=2.82; 95% CI 1.19-6.69; P value = .02) compared to sinus fat invasion or tumoral thrombus only.

CONCLUSION

The concurrent presence of ≥ 2 pT3a features is associated to a higher risk of distant progression, relapse and cancer specific mortality, implying potential role for adjuvant therapy or a more stringent follow-up. Moreover, perirenal fat invasion is associated with worse CSS compared to other pT3a patterns taken alone.

Testosterone in males with COVID-19: a 12-month cohort study

BACKGROUND

Male patients with COVID-19 have been found with reduced serum total testosterone (tT) levels and with more severe clinical outcomes.

OBJECTIVES

To assess total testosterone (tT) levels and the probability of recovering eugonadal tT levels during a minimum 12-month timespan in a cohort of men who have been followed over time after the recovery from laboratory-confirmed COVID-19.

MATERIALS AND METHODS

Demographic, clinical and hormonal values were collected for the overall cohort. Hypogonadism was defined as tT ≤9.2 nmol/l. The Charlson Comorbidity Index was used to score health-significant comorbidities. Descriptive statistics was used to compare hormonal levels at baseline versus 7-month (FU1) versus 12-month (FU2) follow-up, respectively. Multivariate cox proportional hazards regression model was used to identify the potential predictors of eugonadism recovery over time among patients with hypogonadism at the time of infection.

RESULTS

Of the original cohort of 286 patients, follow-up data were available for 121 (42.3%) at FU1 and 63 (22%) patients at FU2, respectively. Higher median interquartile range (IQR) tT levels were detected at FU2 (13.8 (12.3-15.3) nmol/L) versus FU1 (10.2 [9.3-10.9] nmol/L) and versus baseline (3.6 [3.02-4.02] nmol/L) (all p < 0.0001), whilst both LH and E₂ levels significantly decreased over the same time frame (all p ≤ 0.01). Circulating IL-6 levels further decreased at FU2 compared to FU1 levels (19.3 vs. 72.8 pg/ml) (p = 0.02). At multivariable cox regression analyses, baseline tT level (HR 1.19; p = 0.03 [1.02-1.4]) was independently associated with the probability of tT level normalization over time, after adjusting for potential confounders.

CONCLUSIONS

Circulating tT levels keep increasing over time in men after COVID-19. Still, almost 30% of men who recovered from COVID-19 had low circulating T levels suggestive for a condition of hypogonadism at a minimum 12-month follow-up.

Pancreatic metastases after surgery for renal cell carcinoma: survival and pathways of progression

PURPOSE

Metastatic ccRCC has peculiar tropism in the pancreas. We describe the characteristics and pathways of progression of patients with PM in a large multi-institutional consortium and compare them to patients with metastases from ccRCC at other sites.

METHODS

Detailed clinical and histopathological data were collected. To account for differences in baseline characteristics between the two groups, IPTW was used to compare the two groups in terms of PFS and OS.

RESULTS

Of the 182 patients, 33 (18%) had pancreatic, 94 (52%) pulmonary, 30 (16%) bone, 13 (7%) hepatic, and 12 (7%) brain metastases. Patients with PM had less aggressive ccRCC at baseline compared to those with progression at other sites in terms of tumour stage and grade. Median time from ccRCC surgery to PM was 8 (95%CI 5-10) vs. 1 year (95%CI 1-2) for progression to other sites (p < 0.001). Median IPTW-weighted time to second progression was 4.3 years (95%CI 2.4-not reached) for patients with PM vs 1.1 year (95%CI 0.8-2.3) for those with progression in other sites (p < 0.001). The most frequent second progression sites were pancreas (24%) and liver (15%) in patients with PM, while progression to the pancreas was rare (4%) in those with a different first progression site. Surgery alone (55%) or in combination with medical therapy (30%) was more frequent in the PM group than in other sites (p < 0.001). Median IPTW-OS time was longer for patients with PM [8.8 years (95%CI 6.5-not reached)] compared to those with first progression in other sites [2.8 years (95%CI 1.9-4.3), p < 0.001].

CONCLUSION

Pancreatic tropism is typical of ccRCC tumours with more indolent behaviour than those progressing to other sites. A long follow-up period is necessary to distinguish PM from ccRCC.

Testosterone in males with COVID-19: A 7-month cohort study

Background

Circulating testosterone levels have been found to be reduced in men with severe acute respiratory syndrome coronavirus 2 infection, COVID‐19, with lower levels being associated with more severe clinical outcomes.

Objectives

We aimed to assess total testosterone levels and the prevalence of total testosterone still suggesting for hypogonadism at 7‐month follow‐up in a cohort of 121 men who recovered from laboratory‐confirmed COVID‐19.

Materials and methods

Demographic, clinical, and hormonal values were collected for all patients. Hypogonadism was defined as total testosterone ≤9.2 nmol/L. The Charlson Comorbidity Index was used to score health‐significant comorbidities. Descriptive statistics and multivariable linear and logistic regression models tested the association between clinical and laboratory variables and total testosterone levels at follow‐up assessment.

Results

Circulating total testosterone levels increased at 7‐month follow‐up compared to hospital admittance (p < 0.0001), while luteinizing hormone and 17β‐estradiol levels significantly decreased (all p ≤ 0.02). Overall, total testosterone levels increased in 106 (87.6%) patients, but further decreased in 12 (9.9%) patients at follow‐up, where a total testosterone level suggestive for hypogonadism was still observed in 66 (55%) patients. Baseline Charlson Comorbidity Index score (OR 0.36; p = 0.03 [0.14, 0.89]) was independently associated with total testosterone levels at 7‐month follow‐up, after adjusting for age, BMI, and IL‐6 at hospital admittance.

Conclusions

Although total testosterone levels increased over time after COVID‐19, more than 50% of men who recovered from the disease still had circulating testosterone levels suggestive for a condition of hypogonadism at 7‐month follow‐up. In as many as 10% of cases, testosterone levels even further decreased. Of clinical relevance, the higher the burden of comorbid conditions at presentation, the lower the probability of testosterone levels recovery over time.

Severely low testosterone in males with COVID-19: A case-control study

Background

Circulating androgens could have a relevant pathobiological role in clinical outcomes in men with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection (COVID‐19).

Objectives

We aimed to assess: (a) circulating sex steroids levels in a cohort of 286 symptomatic men with laboratory‐confirmed COVID‐19 at hospital admission compared to a cohort of 281 healthy men; and (b) the association between serum testosterone levels (tT), COVID‐19, and clinical outcomes.

Materials and Methods

Demographic, clinical, and hormonal values were collected for all patients. Hypogonadism was defined as tT ≤9.2 nmol/l. The Charlson Comorbidity Index (CCI) was used to score health‐significant comorbidities. Severe clinical outcomes were defined as patients either transferred to intensive care unit (ICU) or death. Descriptive statistics and multivariable linear and logistic regression models tested the association between clinical and laboratory variables and tT levels. Univariable and multivariable logistic regression models tested the association between tT and severe clinical outcomes.

Results

Overall, a significantly lower levels of LH and tT were found in patients with COVID‐19 compared to healthy controls (all p < 0.0001); conversely, healthy controls depicted lower values of circulating E₂ (p < 0.001). Testosterone levels suggestive for hypogonadism were observed in 257 (89.8%) patients at hospital admission. In as many as 243 (85%) cases, hypogonadism was secondary. SARS‐CoV‐2 infection status was independently associated with lower tT levels (p < 0.0001) and greater risk of hypogonadism (p < 0.0001), after accounting for age, BMI, CCI, and IL‐6 values. Lower tT levels were associated with higher risk of ICU admission and death outcomes (all p ≤ 0.05), after accounting for clinical and laboratory parameters.

Conclusions

We unveil an independent association between SARS‐CoV‐2 infection status and secondary hypogonadism already at hospital admission, with lower testosterone levels predicting the most severe clinical outcomes.

Comparison of LI-RADS with other non-invasive liver MRI criteria and radiological opinion for diagnosing hepatocellular carcinoma in cirrhotic livers using gadoxetic acid with histopathological explant correlation

AIM

To establish the diagnostic accuracy of the Liver Imaging Reporting and Data System (LI-RADS) for hepatocellular carcinoma (HCC) and compare its performance to that of international criteria from European Assofor the Study of the Liver (EASL), Japan Society of Hepatology (JSH), Asian Pacific Association for the Study of the Liver (APASL), and Organ Procurement and Transplantation Network (OPTN), and to the reporting radiologist's overall opinion regarding the probability of a nodule being a HCC by correlating with a histological diagnosis from whole liver explants.

MATERIALS AND METHODS

The present single-centre, retrospective review selected participants based on the following criteria: adults (≥18 years) listed for liver transplantation in 2014/2015, with liver cirrhosis at the time of magnetic resonance imaging (MRI) with hepatocyte specific contrast agent, and at least one liver lesion ≥10 mm on MRI with histology from subsequent liver explant for comparison. Each lesion was assessed against international criteria and given a "radiologist opinion" score of 1-5 (1 = definitely benign, 5 = definitely HCC).

RESULTS

Total 268 patient records were reviewed, with 105 eligible lesions identified from 47 patients. Median lesion size was 15.5 mm (range 10-68 mm). Sensitivity (%), specificity (%), and positive predictive value (PPV; %) for LI-RADS LR5 was 45, 89, and 89, for LI-RADS LR4+5 + TIV was 61, 80, and 86, for EASL was 44, 86 and 86, for JSH/APASL was 64, 81, and 87, for OPTN was 36, 90, and 88, and for "radiologist impression" of probably or definitely HCC was 79, 79, and 88 respectively.

CONCLUSIONS

MRI has moderate sensitivity and good specificity for the diagnosis of HCC with considerable variation depending on criteria used. OPTN criteria have the best specificity, but low sensitivity. "Radiologist opinion" gives highest overall accuracy with increases in sensitivity and reduction in specificity when compared to the imaging criteria.

Liver transplantation outcomes after transarterial chemotherapy for hepatocellular carcinoma

Background

Transarterial chemoembolization (TACE) in patients with hepatocellular carcinoma (HCC) awaiting liver transplantation is widespread, although evidence that it improves outcomes is lacking and there exist concerns about morbidity. The impact of TACE on outcomes after transplantation was evaluated in this study.

Methods

Patients with HCC who had liver transplantation in the UK were identified, and stratified according to whether they received TACE between 2006 and 2016. Cox regression methods were used to estimate hazard ratios (HRs) for death and graft failure after transplantation adjusted for donor and recipient characteristics.

Results

In total, 385 of 968 patients (39·8 per cent) received TACE. Five-year patient survival after transplantation was similar in those who had or had not received TACE: 75·2 (95 per cent c.i. 68·8 to 80·5) and 75·0 (70·5 to 78·8) per cent respectively. After adjustment for donor and recipient characteristics, there were no differences in mortality (HR 0·96, 95 per cent c.i. 0·67 to 1·38; P = 0·821) or graft failure (HR 1·01, 0·73 to 1·40; P = 0·964). The number of TACE treatments (2 or more versus 1: HR 0·97, 0·61 to 1·55; P = 0·903) or the time of death after transplantation (within or after 90 days; P = 0·291) did not alter the outcome. The incidence of hepatic artery thrombosis was low in those who had or had not received TACE (1·3 and 2·4 per cent respectively; P = 0·235).

Conclusion

TACE delivered to patients with HCC before liver transplant did not affect complications, patient death or graft failure after transplantation.

Short- and long-term mortality after liver transplantation in patients with and without hepatocellular carcinoma in the UK

Background

The increasing demand for liver transplantation has led to considerable changes in characteristics of donors and recipients. This study evaluated the short- and long-term mortality of recipients with and without hepatocellular carcinoma (HCC) in the UK between 1997 and 2016.

Methods

First-time elective adult liver transplant recipients in the UK were identified and four successive eras of transplantation were compared. Hazard ratios (HRs) comparing the impact of era on short-term (first 90 days) and longer-term (from 90 days to 5 years) mortality were estimated, with adjustment for recipient and donor characteristics.

Results

Some 1879 recipients with and 7661 without HCC were included. There was an increase in use of organs donated after circulatory death (DCD), from 0 per cent in era 1 to 35·2 per cent in era 4 for recipients with HCC, and from 0·2 to 24·1 per cent for non-HCC recipients. The 3-year mortality rate decreased from 28·3 per cent in era 1 to 16·9 per cent in era 4 (adjusted HR 0·47, 95 per cent c.i. 0·35 to 0·63) for recipients with HCC, and from 20·4 to 9·3 per cent (adjusted HR 0·44, 0·36 to 0·53) for those without HCC. Comparing era 4 with era 1, improvements were more marked in short-term than in long-term mortality, both for recipients with HCC (0–90 days: adjusted HR 0·20, 0·10 to 0·39; 90 days to 5 years: adjusted HR 0·52, 0·35 to 0·75; P = 0·043) and for non-HCC recipients (0–90 days: adjusted HR 0·32, 0·24 to 0·42; 90 days to 5 years: adjusted HR 0·52, 0·40 to 0·67; P = 0·024).

Conclusion

In the past 20 years, the mortality rate after liver transplantation has more than halved, despite increasing use of DCD donors. Improvements in overall survival can be explained by decreases in short-term and longer-term mortality.

The first national clinical audit for rheumatoid arthritis

The first national audit for rheumatoid and early inflammatory arthritis has benchmarked care for the first 3 months of follow-up activity from first presentation to a rheumatology service. Access to care, management of early rheumatoid arthritis and support for self care were measured against National Institute for Health and Care Excellence quality standards; impact of early arthritis and experience of care were measured using patient-reported outcome and experience measures. The results demonstrate delays in referral and accessing specialist care and the need for service improvement in treating to target, suppression of high levels of disease activity and support for self-care. Improvements in patient-reported outcomes within 3 months and high levels of overall satisfaction were reported but these results were affected by low response rates. This article presents a summary of the national data from the audit and discusses the implications for nursing practice.

2-Deoxy-d-Glucose Ameliorates PKD Progression

Autosomal dominant polycystic kidney disease (ADPKD) is an important cause of ESRD for which there exists no approved therapy in the United States. Defective glucose metabolism has been identified as a feature of ADPKD, and inhibition of glycolysis using glucose analogs ameliorates aggressive PKD in preclinical models. Here, we investigated the effects of chronic treatment with low doses of the glucose analog 2-deoxy-d-glucose (2DG) on ADPKD progression in orthologous and slowly progressive murine models created by inducible inactivation of the Pkd1 gene postnatally. As previously reported, early inactivation (postnatal days 11 and 12) of Pkd1 resulted in PKD developing within weeks, whereas late inactivation (postnatal days 25-28) resulted in PKD developing in months. Irrespective of the timing of Pkd1 gene inactivation, cystic kidneys showed enhanced uptake of (13)C-glucose and conversion to (13)C-lactate. Administration of 2DG restored normal renal levels of the phosphorylated forms of AMP-activated protein kinase and its target acetyl-CoA carboxylase. Furthermore, 2DG greatly retarded disease progression in both model systems, reducing the increase in total kidney volume and cystic index and markedly reducing CD45-positive cell infiltration. Notably, chronic administration of low doses (100 mg/kg 5 days per week) of 2DG did not result in any obvious sign of toxicity as assessed by analysis of brain and heart histology as well as behavioral tests. Our data provide proof of principle support for the use of 2DG as a therapeutic strategy in ADPKD.

Impaired glomerulogenesis and endothelial cell migration in Pkd1-deficient renal organ cultures

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The PKD1 gene, mutated in ADPKD is developmentally regulated in the kidney.

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Renal organ cultures of two distinct Pkd1 mutants display normal UB branching.

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Glomeruli fail to properly develop in Pkd1 mutant renal organ cultures.

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Defective endothelial cell migration likely accounts for glomerulogenesis defects.

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PI3kinase inhibitors phenocopy the Pkd1 phenotype, VEGF minimally improves it.

The PKD1 gene is essential for a number of biological functions, and its loss-of-function causes autosomal dominant polycystic kidney disease (ADPKD). The gene is developmentally regulated and believed to play an essential role in renal development. Previous studies have shown that manipulating murine renal organ cultures with dominant-negative forms of the Pkd1 gene impaired ureteric bud (UB) branching. In the current study, we analyzed different stages of renal development in two distinct mouse models carrying either a null mutation or inactivation of the last two exons of Pkd1. Surprisingly, metanephric explants from Pkd1-deleted kidneys harvested at day E11.5 did not show defects of UB branching and elongation, estimated by cytokeratin staining on fixed tissues or by Hoxb7-GFP time-lapse imaging. However, renal explants from Pkd1-mutants isolated at day E14.5 showed impaired nephrogenesis. Notably, we observed cell migratory defects in the developing endothelial compartment. Previous studies had implicated the Pkd1 gene in controlling cell migration and collagen deposition through PI3 kinases. In line with these studies, our results show that wild-type explants treated with PI3-kinase inhibitors recapitulate the endothelial defects observed in Pkd1 mutants, whereas treatment with VEGF only partially rescued the defects. Our data are consistent with a role for the Pkd1 gene in the endothelium that may be required for proper nephrogenesis.

Defective metabolism in polycystic kidney disease: potential for therapy and open questions

Autosomal dominant polycystic kidney disease (ADPKD) is a common genetic disorder characterized by bilateral renal cyst formation. The disease is caused by mutations in either the PKD1 or the PKD2 gene. Progress has been made in understanding the molecular basis of the disease leading to the general agreement on ADPKD being a loss-of-function disease. Identification of signalling cascades dysfunctional in the cystic epithelia has led to several pre-clinical studies of animal models using a variety of inhibitors to slow disease progression. These were followed by clinical trials, some of which generated promising results, although an approved therapy is still lacking. Here, we summarize and discuss recent work providing evidence that metabolic alterations can be observed in ADPKD. In particular, we will focus our discussion on the potential role of glucose metabolism in the pathogenesis of ADPKD. These recent findings provide a new perspective for the understanding of the pathobiology of ADPKD and open potential new avenues for therapeutical approaches. At the same time, these studies also raise important and intriguing biological and medical questions that will need to be addressed experimentally prior to embracing a more enthusiastic view of the applicability of the results.

Defective glucose metabolism in polycystic kidney disease identifies a new therapeutic strategy

Autosomal dominant polycystic kidney disease (ADPKD) is a common genetic disorder characterized by bilateral renal cyst formation. Recent identification of signaling cascades deregulated in ADPKD has led to the initiation of several clinical trials, but an approved therapy is still lacking. Using a metabolomic approach, we identify a pathogenic pathway in this disease that can be safely targeted for therapy. We show that mutation of PKD1 results in enhanced glycolysis in cells in a mouse model of PKD and in kidneys from humans with ADPKD. Glucose deprivation resulted in lower proliferation and higher apoptotic rates in PKD1-mutant cells than in nondeprived cells. Notably, two distinct PKD mouse models treated with 2-deoxyglucose (2DG), to inhibit glycolysis, had lower kidney weight, volume, cystic index and proliferation rates as compared to nontreated mice. These metabolic alterations depend on the extracellular signal-related kinase (ERK) pathway acting in a dual manner by inhibiting the liver kinase B1 (LKB1)-AMP-activated protein kinase (AMPK) axis on the one hand while activating the mTOR complex 1 (mTORC1)-glycolytic cascade on the other. Enhanced metabolic rates further inhibit AMPK. Forced activation of AMPK acts in a negative feedback loop, restoring normal ERK activity. Taken together, these data indicate that defective glucose metabolism is intimately involved in the pathobiology of ADPKD. Our findings provide a strong rationale for a new therapeutic strategy using existing drugs, either individually or in combination.

Nephrocystin-1 forms a complex with polycystin-1 via a polyproline motif/SH3 domain interaction and regulates the apoptotic response in mammals

Mutations in PKD1, the gene encoding for the receptor Polycystin-1 (PC-1), cause autosomal dominant polycystic kidney disease (ADPKD). The cytoplasmic C-terminus of PC-1 contains a coiled-coil domain that mediates an interaction with the PKD2 gene product, Polycystin-2 (PC-2). Here we identify a novel domain in the PC-1 C-terminal tail, a polyproline motif mediating an interaction with Src homology domain 3 (SH3). A screen for interactions using the PC-1 C-terminal tail identified the SH3 domain of nephrocystin-1 (NPHP1) as a potential binding partner of PC-1. NPHP1 is the product of a gene that is mutated in a different form of renal cystic disease, nephronophthisis (NPHP). We show that in vitro pull-down assays and NMR structural studies confirmed the interaction between the PC-1 polyproline motif and the NPHP1 SH3 domain. Furthermore, the two full-length proteins interact through these domains; using a recently generated model system allowing us to track endogenous PC-1, we confirm the interaction between the endogenous proteins. Finally, we show that NPHP1 trafficking to cilia does not require PC-1 and that PC-1 may require NPHP1 to regulate resistance to apoptosis, but not to regulate cell cycle progression. In line with this, we find high levels of apoptosis in renal specimens of NPHP patients. Our data uncover a link between two different ciliopathies, ADPKD and NPHP, supporting the notion that common pathogenetic defects, possibly involving de-regulated apoptosis, underlie renal cyst formation.

Caspase-9 regulates apoptosis/proliferation balance during metamorphic brain remodeling in Xenopus

During anuran metamorphosis, the tadpole brain is transformed producing the sensorial and motor systems required for the frog's predatory lifestyle. Nervous system remodeling simultaneously implicates apoptosis, cell division, and differentiation. The molecular mechanisms underlying this remodeling have yet to be characterized. Starting from the observation that active caspase-9 and the Bcl-X(L) homologue, XR11 are highly expressed in tadpole brain during metamorphosis, we determined their implication in regulating the balance of apoptosis and proliferation in the developing tadpole brain. In situ hybridization showed caspase-9 mRNA to be expressed mainly in the ventricular area, a site of neuroblast proliferation. To test the functional role of caspase-9 in equilibrating neuroblast production and elimination, we overexpressed a dominant-negative caspase-9 protein, DN9, in the tadpole brain using somatic gene transfer and germinal transgenesis. In both cases, abrogating caspase-9 activity significantly decreased brain apoptosis and increased numbers of actively proliferating cells in the ventricular zone. Moreover, overexpression of XR11 with or without DN9 was also effective in decreasing apoptosis and increasing cell division in the tadpole brain. We conclude that XR11 and caspase-9, two key members of the mitochondrial death pathway, are implicated in controlling the proliferative status of neuroblasts in the metamorphosing Xenopus brain. Modification of their expression during the critical period of metamorphosis alters the outcome of metamorphic neurogenesis, resulting in a modified brain phenotype in juvenile Xenopus.

Apoptosis of tail muscle during amphibian metamorphosis involves a caspase 9-dependent mechanism

The climax of amphibian metamorphosis is marked by thyroid hormone-dependent tadpole tail resorption, implicating apoptosis of multiple cell types, including epidermal cells, fibroblasts, nerve cells, and muscles. The molecular cascades leading to and coordinating the death of different cell types are not fully elucidated. It is known that the mitochondrial pathway, and in particular the Bax and XR11 genes, regulates the balance between apoptosis and survival in muscle. However, the down-stream factors modulated by changes in mitochondrial permeability have not been studied in a functional context. To investigate further the mitochondrial-dependent pathway, we analyzed the regulation and the role of caspase 9 in Xenopus tadpoles. We report that caspase 9 mRNA is expressed in the tail before metamorphosis and increases before and during climax. Similarly, at the protein level, the production of active forms of caspase 9 increases in muscle tissue as metamorphosis progresses. To assess the functional role of caspase 9, we designed a dominant-negative protein. Overexpression of this dominant-negative abrogates both Bax-induced cell death in vitro and muscle apoptosis in vivo during natural metamorphosis. These findings consolidate a model of metamorphic muscle death that directly implicates the mitochondrial pathway and the apoptosome.

Autonomous regulation of muscle fibre fate during metamorphosis in Xenopus tropicalis

A key event in metamorphosis of anuran amphibians is tail resorption. This composite structure includes epidermal cells, spinal cord, muscle fibres and connective tissue. It is unclear how resorption proceeds and to what extent the signals for the death process are transmitted between cells. We determined the kinetics of metamorphosis, apoptosis, and tail regression in the diploid anuran, Xenopus tropicalis, a species more suited to genetic analysis than the pseudotetraploid, Xenopus laevis. Metamorphosis was found to proceed at a regular and predictable rate in X. tropicalis but not in X. laevis. Caspase 3 activity and mRNA levels were correlated with TdT-mediated dUTP nick end-labeling (TUNEL) signalling and most markedly increased in tail muscle and spinal cord. It has been proposed that muscles die as a result of loss of connectivity with the surrounding matrix. To test this hypothesis, we used direct DNA injection in trunk and tail muscle to overexpress Xenopus Bcl-X(L) (xR11), an anti-apoptotic gene, along with a marker gene (luciferase or GFP). xR11 significantly inhibited the cell death process in both trunk and tail muscle. This protection was functional even up to stage 64 on completion of tail regression. We conclude that (1) somatic gene transfer can be applied to analyse cell fate in X. tropicalis, and (2) that muscle death can be abrogated despite extracellular matrix loss.

Gastro-oesophageal reflux and duodenogastric reflux before and after eradication in Helicobacter pylori gastritis

OBJECTIVE

Helicobacter pylori and duodenogastric reflux (DGR) are both associated with chronic gastritis, peptic ulcer and gastric cancer. The nature of their interrelationship remains unclear. H. pylori eradication has also been reported to result in new or worsening acid gastro-oesophageal reflux (GOR). The aim of this study was to investigate the relationship between GOR, DGR and H. pylori infection.

METHOD

25 patients with H. pylori gastritis underwent ambulatory 24-hour oesophageal and gastric pHmetry and gastric bilirubin monitoring before and 12 weeks after H. pylori eradication, confirmed by 14C urea breath testing (UBT). Ten healthy subjects served as a control group.

RESULTS

There were no differences between patient and control groups for gastric alkaline exposure or gastric bilirubin exposure (P> 0.25 in all categories). Oesophageal acid reflux was higher in the study group (P< 0.02). No differences were detected in oesophageal acid reflux, gastric alkaline exposure, or gastric bilirubin exposure (P = 0.35, 0.18 and 0.11, respectively) before and after eradication.

CONCLUSIONS

Acid GOR is not increased by H. pylori eradication. DGR in patients with H. pylori gastritis is similar to that in healthy, non-infected subjects. H. pylori eradication produces no change in GOR or DGR. In patients with chronic gastritis, H. pylori infection and DGR appear to be independent of each other.

The isolated hypertensive lower oesophageal sphincter: audit in a specialist unit

The hypertensive lower oesophageal sphincter (HLOS) is a distinct clinical entity defined by a lower oesophageal sphincter (LOS) pressure > or = 30mmHg and normal LOS relaxation and oesophageal peristalsis. The clinical, physiological, and radiological details of 27 patients with HLOS diagnosed in a 3-year period were reviewed. The reasons for referral included: gastro-oesophageal reflux disease (GORD) (33%), dysphagia (18.5%), epigastric discomfort (11%), non-cardiac chest pain (15%), globus (7.5%) and other (15%). All patients had manometric evidence of HLOS (Median LOS pressure 30 mmHg, range 25-50 mmHg) and 6 patients (20.7%) had abnormal pH studies. Less than 22% of contrast studies demonstrated an abnormality. There was no change in manometric findings following pharmacological treatment. Two patients underwent oesophagomyotomy and had normal manometry on follow up. We conclude that HLOS mimics a variety of upper gastrointestinal disorders and oesophageal manometry is the gold standard of diagnosis. There was an unexpectedly high incidence of GORD (22%) in this group. The significance and treatment of HLOS is discussed.