A randomized, open-label, multicenter study evaluating the efficacy of peginterferon alfa-2a versus interferon alfa-2a, in combination with ribavirin, in naïve and relapsed chronic hepatitis C patients

BACKGROUND/AIMS

A large multicenter trial to compare the efficacy of peginterferon alfa-2a with interferon alfa-2a, in combination with ribavirin, in chronic hepatitis C patients. Efficacy data for prior relapsers are reported because treatment recommendations for this patient population are not well defined.

PATIENTS AND METHODS

This study was a multicenter, prospective, randomized clinical trial. The primary efficacy endpoint was sustained virologic response in naive patients (n = 348) and relapsers (n = 95).

RESULTS

Sustained virologic response rates were similar in naïve patients and relapsers, both for non-pegylated and pegylated interferon (respectively 27 and 26% and 54 and 43%). Pegylated interferon given for 48 weeks did not improved the relapse rate: 15.9 and 27.3% for non-pegylated and 16.7 and 30.4% for pegylated interferon, naïve vs relapsers respectively. Stepwise logistic regression analysis revealed a significant association between slow response (detectable HCV RNA at week 12 and undetectable at week 24) and relapse in patients with an end-of-treatment response (55% versus 13% respectively; p = 0.02; odds ratio = 6.07).

CONCLUSIONS

This trial confirms the value of using peginterferon alfa-2a in both naïve and relapsed patients and provides support for a more tailored approach to treatment for relapsers and particulary for patients with a slow viral response.

The DosR regulon of M. tuberculosis and antibacterial tolerance

Adaptation of Mycobacterium tuberculosis to an anaerobic dormant state that is tolerant to several antibacterials is mediated largely by a set of highly expressed genes controlled by DosR. A DosR mutant was constructed to investigate whether the DosR regulon is involved in antibacterial tolerance. We demonstrate that induction of the regulon is not required for drug tolerance either in vivo during a mouse infection or in vitro during anaerobic dormancy. Thus, drug tolerance observed in these models is due to other mechanisms such as the bacilli simply being in a non-replicating or low metabolic state. Our data also demonstrate that the DosR regulon is not essential for virulence during chronic murine infection. However, decreased lung pathology was observed in the DosR mutant. We also show that the DosR regulon genes are more highly conserved in environmental mycobacteria, than in pathogenic mycobacteria lacking a latent phase or environmental reservoir. It is possible that the DosR regulon could contribute to drug tolerance in human infections; however, it is not the only mechanism and not the primary mechanism for tolerance during a mouse infection. These data suggest that the regulon evolved not for pathogenesis or drug tolerance but for adaptation to anaerobic conditions in the environment and has been adapted by M. tuberculosis for survival during latent infection.

[How to detect the complications of the cirrhosis?]

The occurrence of complications marks a turn in the natural history of cirrhosis. The early management, the etiologic treatment of the subjacent disease, the methodological detection of hepatocarcinoma, the prophylaxis of digestive bleeding linked to portal hypertension, the control of ascite and prevention of hepato-renal syndrome allow to improve the prognosis of these patients. Moreover, bacterial infection represents one of the principal factor facilitating the occurrence of another complication. This is why any complication should be considered as secondary to bacterial infection until the refutation.

Interest of the association clonidine-spironolactone in cirrhotic patients with ascites and activation of sympathetic nervous system

BACKGROUND

The aim of this study was to examine the effects of spironolactone, clonidine and the association of clonidine-spironolactone on renin-aldosterone and sympathetic systems, renal function, systemic hemodynamics and mobilization of ascites in 32 alcoholic cirrhotic patients with marked increase in sympathetic system.

METHODS

Measurements were taken before and after an 8-day treatment with spironolactone (200 mg/day), after an 8-day treatment with clonidine (0.150 mg/day) and 10 days after adjunction of spironolactone (200 mg/day) to clonidine.

RESULTS

Three patients abandoned the treatment or were excluded because lack of compliance. Spironolactone alone induced an increase in renin-aldosterone and sympathetic systems without any remarkable increase of natriuresis and body weight loss. Given for 8 days, clonidine alone induced a significant decrease in plasma norepinephrine associated with a significant increase in glomerular filtration rate without effect on natriuresis. In contrast, 10 days after adjunction of spironolactone to clonidine, plasma renin and aldosterone significantly decreased, natriuresis increased (from 7.4 +/- 0.7 to 41.6 +/- 3.2 mEq/24 h) and body weight decreased (from 66.03 +/- 2.3 to 63.5 +/- 2.3 kg) without adverse effects.

CONCLUSION

In cirrhotic patients with ascites and marked activation of sympathetic nervous system, spironolactone (200 mg/day) is unable to mobilize ascites. In these patients, after 8 days, clonidine decreases sympathetic activity, increases glomerular filtration rate and after 18 days, decreases plasma renin and aldosterone concentrations allowing a better action of spironolactone. The association clonidine-spironolactone enhances natriuresis and body weight loss.

Reproducibility and reliability of measurements using a linear isokinetic dynamometer, Aristokin

BACKGROUND

This study was performed to investigate the intra-observer reproducibility and reliability of measurements using a linear isokinetic dynamometer (Aristokin).

METHODS

Sixteen female volunteers (age 18 to 23 years) participated in 4 test sessions, each consisting of 6 warming-up movements followed by 6 repetitions of 4 different movements. During each session, the subjects consecutively performed lifting movements by flexing elbows and shoulders (at 65 cm per sec), total lifting movements with arms and legs (at 65 cm per sec), and extension movements of the legs in sitting position (at 40 and 60 cm per sec). The first 3 test sessions were performed at a weekly interval, the 4th was executed 4 weeks after the 3rd session. Force, power and explosivity (force developed per sec) were recorded.

RESULTS

The intra-observer reproducibility was investigated of the 6 repetitions of the movements during each test session. The highest reproducibility for mean peak power and force was found in the combination of the 3rd, 4th, 5th and 6th measurement (intraclass correlation coefficient 0.85 to 0.99). Using this combination, the intra-observer reliability was investigated, defined as the consistency of results obtained during the 4 test sessions, performed at a weekly or longer interval. Comparison between these sessions showed that the results for mean force in the arm movement differed significantly (p=0.01) although a high between sessions correlation was found (0.96). Results for mean force and power for the 3 other movements were reliable, and no significant learning effect was observed. Lower reliability and reproducibility were observed for other parameters including explosivity and power and force at the first 0.25 sec of the test movement.

CONCLUSIONS

Even after standard warming-up movements, the first 2 out of 6 measurement repetitions during a test session are not reproducible and should not be used in calculations of the results. For the combination of the 3rd to 6th repetitions, a high reliability was found for the measurement of mean force and power of the total lifting movement and of the sitting leg extension movements repeated in 4 sessions over a period of 6 weeks.

[Biological factors influencing response to diuretics in patients with cirrhosis and ascites]

PURPOSES

To examine the biological factors influencing response to diuretics in patients with cirrhosis and ascites.

METHODS

Sixty-nine patients were evaluated. Patients were classified into 3 groups: group 1: "good responders" (responding to spironolactone 200 mg/day), group 2: "bad responders" (responding to spironolactone doses above 200 mg/day or requiring addition of furosemide), and group 3: "non-responders" (not responding to spironolactone 400 mg/day and furosemide 160 mg/day).

RESULTS

There were 30 patients in group 1, 24 in group 2 and 15 in group 3. The degree of activation of the renin-aldosterone and sympathetic system in group 2 was significantly higher than in group 1 and lower than in group 3. Natriuresis in group 2 (11 +/- 0.7 mEq/24h) was significantly below group 1 (20 +/- 2 mEq/24h) and above group 3 (5 +/- 0.6 mEq/24h).

CONCLUSIONS

In patients with cirrhosis and ascites, the degree of activation of the renin-aldosterone and sympathetic nervous system influences diuretic response of ascites and is estimated by measured baseline natriuresis.

[Diagnosis and treatment of gastroesophageal reflux in the adult: guidelines recommended by French and Belgian consensus]

Usual gastroesophageal reflux (GER) presentations are heartburn and acid regurgitation. The prevalence in occidental population ranges from 5 to 45% according to symptoms frequency. Oesophagitis is observed in 30 to 50% of examined patients and only erosive and ulcerative lesions must be considered. Distinction is made between non-severe oesophagitis (isolated loss of substance), severe oesophagitis (circonferential loss of substance) and complicated oesophagitis (stenosis, ulcerations, brachyoesophagus). 24-hour pH-monitoring analyses reflux duration and relations between symptoms and reflux specially in unusual extraoesophageal presentations. Symptoms and quality of life are the main criteria for staging. In few patients, oesophagitis is severe. Complications (stenosis, ulcerations, bleeding, endobrachyoesophagus) are observed in 10 to 15% of cases. Endobrachyoesophagus with intestinal metaplasia is a risk for neoplasia. The consensus conference proposes this initial therapeutic strategy. In cases of time-spaced symptoms: antiacids, alginic acid or low doses of anti-H2 with life style changes. In cases of typical frequent symptoms, in patients younger than 50 years: 4-weeks treatment with half dosed proton pump inhibitors (PPI) or standard doses of anti-H2 or prokinetics. Nowadays, the majority of the experts propose empiric full-dose treatment. This attitude is more logical as total symptoms suppression with full dose PPI brings positive clues for exact GOR diagnostic without endoscopy. In patients older than 50 years or with alarming symptoms (weight loss, dysplagia, bleeding, anemia): endoscopy must be performed. Patients with non severe oesophagitis: PPI without checking endoscopy. In patients with severe or complicated oesophagitis: 8-weeks treatment following by endoscopy; in non relieved patients: doses are increased. In cases of extraoesophageal presentations: standard PPI treatment during 4 to 8 weeks if GER is well established. In long term strategy, if recidives are rare: intermittent treatment. In early and frequent recidives: long term adapted PPI or surgery. Stenosis are treated by PPI, pneumatic dilatation or surgery if unsuccessful. Brachyoesophagus must be checked by endoscopy every 2 years (malignancy risk).

[Diagnostic strategies for ischemic enteropathies]

Mesenteric ischemia is a life threatening event instead of colic ischemia which recovers in 90% of cases. Three points will be investigated: chronic mesenteric ischemia; acute mesenteric ischemia; colic ischemia.

[Hepatitis A and B vaccines]

Hepatitis A is a beginning disease in childhood but sometimes a very dangerous disease in adults. It is necessary to vaccine the non immune "risk groups". Hepatitis B is responsible for two millions deafs every year. Hepatitis B is a sexually transmissible disease. Everybody would be vaccinated.

Expression of an exogenous tumor necrosis factor (TNF) gene in TNF-sensitive cell lines confers resistance to TNF-mediated cell lysis

TNF, a cytokine with cytotoxic activity on a variety of tumor cells, is mainly produced by macrophages; however, some tumor cell types of non-macrophage origin, apparently resistant to TNF-mediated cell lysis, can also produce TNF. It is not clear whether these cells were TNF-resistant a priori or whether protective mechanisms against toxicity of autocrine TNF may be induced in TNF-producing cells. Murine L929sA fibrosarcoma cells, which are highly sensitive to TNF cytotoxicity, were transfected with the neomycin resistance (neor) gene, alone or in combination with the human (h) or the murine (m) TNF gene. All exogenous genes were under control of the constitutive SV40 early promoter. After cotransfection, the number of neor colonies was 10 to 100% as compared with the number of colonies upon transfection with the neor gene alone. An appreciable fraction of these colonies (50-100%) constitutively produced biologically active TNF. mTNF-producing L929 cells were fully TNF resistant, whereas hTNF-producing cells showed partial TNF resistance. Specific TNF binding could not be detected on mTNF-producing L929sA transfectants, whereas hTNF-producing cells showed reduced TNF binding. Apparently, TNF gene expression, even in a priori TNF-sensitive cells, can induce mechanisms to prevent toxicity by both autocrine and exogenous TNF. No TNF resistance was induced by expression of a gene sequence encoding the 9-kDa membrane-bound presequence part of the 26-kDa mTNF proform. Expression of a mutant 26-kDa TNF gene coding for a quasi-inactive mature mTNF induced only weak TNF resistance as compared with the complete resistance obtained after transfection with the wild-type gene. These findings show that the membrane-bound TNF presequence as such is not sufficient for induction of TNF resistance and imply that the active site of mature TNF is involved in modulation of TNF responsiveness upon autocrine TNF production.

Expression of an exogenous tumor necrosis factor (TNF) gene in TNF-sensitive cell lines confers resistance to TNF-mediated cell lysis

TNF, a cytokine with cytotoxic activity on a variety of tumor cells, is mainly produced by macrophages; however, some tumor cell types of non-macrophage origin, apparently resistant to TNF-mediated cell lysis, can also produce TNF. It is not clear whether these cells were TNF-resistant a priori or whether protective mechanisms against toxicity of autocrine TNF may be induced in TNF-producing cells. Murine L929sA fibrosarcoma cells, which are highly sensitive to TNF cytotoxicity, were transfected with the neomycin resistance (neor) gene, alone or in combination with the human (h) or the murine (m) TNF gene. All exogenous genes were under control of the constitutive SV40 early promoter. After cotransfection, the number of neor colonies was 10 to 100% as compared with the number of colonies upon transfection with the neor gene alone. An appreciable fraction of these colonies (50-100%) constitutively produced biologically active TNF. mTNF-producing L929 cells were fully TNF resistant, whereas hTNF-producing cells showed partial TNF resistance. Specific TNF binding could not be detected on mTNF-producing L929sA transfectants, whereas hTNF-producing cells showed reduced TNF binding. Apparently, TNF gene expression, even in a priori TNF-sensitive cells, can induce mechanisms to prevent toxicity by both autocrine and exogenous TNF. No TNF resistance was induced by expression of a gene sequence encoding the 9-kDa membrane-bound presequence part of the 26-kDa mTNF proform. Expression of a mutant 26-kDa TNF gene coding for a quasi-inactive mature mTNF induced only weak TNF resistance as compared with the complete resistance obtained after transfection with the wild-type gene. These findings show that the membrane-bound TNF presequence as such is not sufficient for induction of TNF resistance and imply that the active site of mature TNF is involved in modulation of TNF responsiveness upon autocrine TNF production.

Two discrete types of tumor necrosis factor-resistant cells derived from the same cell line

From the murine fibrosarcoma cell line L929s, which is sensitive to tumor necrosis factor (TNF)-mediated cell lysis, two discrete types of TNF-resistant variants were derived by TNF selection. Cells of the first type (named L929r1) were not sensitized to TNF cytotoxicity by cotreatment with either inhibitors of protein or RNA synthesis, or gamma-interferon, despite the presence of a functional gamma-interferon response. L929r1 constitutively produced TNF in the supernatant and expressed membrane-bound TNF, which was not bound to the TNF receptor. In fact, TNF receptors could not be demonstrated on L929r1 cells, not even after low pH treatment and/or incubation with antiserum to TNF. L929r1 exhibited a stable TNF-resistant phenotype in the absence of further TNF selection. No evidence could be obtained that TNF acted as an autocrine growth factor for these cells. L929r2, the second type of TNF-resistant L929 cells, became sensitive to TNF lysis in the presence of RNA or protein synthesis inhibitors, or in the presence of gamma-interferon. TNF induced the secretion of interleukin 6 in these cells, additionally showing that functional TNF signaling in these cells indeed takes place, but does not lead to cell lysis under normal conditions. L929r2 did not produce TNF, also not upon stimulation with exogenous TNF. The number and binding affinity of TNF receptors were not consistently different between L929s and L929r2 cells. In the absence of further TNF selection, L929r2 gradually reverted to TNF sensitivity. This sensitivity was not reversible to TNF resistance by the gene-regulatory agents 5-azacytidine or sodium butyrate. Treatment with these agents also did not affect the TNF sensitivity of L929s cells nor the TNF resistance of L929r1 and L929r2 cells. In summary, our results suggest the existence among cells of the same cell line of discrete mechanisms for acquisition of resistance to TNF-mediated cell lysis.

Health and social inequities in Belgium

This paper presents two different yet complementary on-going studies related to the understanding of the mechanisms leading to social inequalities in health. The first part is devoted to a differential morbidity survey held in southern Belgium. It confirms that striking differences exist in the period around birth between social categories, and between the three districts under study. In a multivariate approach, differences remain between the social categories and between the district samples, which classically studied socio-demographical, behavioural and medical characteristics cannot fully explain. The role of cultural factors is analysed and discussed through the concept of 'health culture' and alternative hypotheses are reviewed in the light of the results. The second part reviews the studies conducted on the so-called avoidable mortality in the EEC and more specifically in Belgium. The concept of avoidable mortality is discussed, as well as its utility from the standpoint of the present concern on social inequalities. Differences between EEC countries are large, and even within Belgium there are important disparities between the districts. The role of health care supply has not been demonstrated yet in these two contexts. For Belgium, it appears that a major part of the unequally distributed mortality is constituted by causes of death considered as avoidable. Moreover, the most discriminating causes of death are overrepresented in socially deprived districts. The two perspectives are confronted in order to delineate perspectives for future research and operational outcomes for policy making and interventions.

Agrocinopine A, a phosphorylated opine is secreted from crown gall cells

We showed that phosphorus-containing metabolites of crown gall tissues were all taken up by appropriate pTi+ agrobacteria. All but one were also taken up by pTi- bacteria. This one compound, produced by nopaline-, but not by octopine-type tumours, was the only phosphorylated organic compound actively secreted by healthy crown gall cells, and it appears to be agrocinopine A. Testing crown gall cell exudates may be a general procedure for the identification of opines by transformed plant cells.