Anti-viral therapy in haemodialysed HCV patients: efficacy, tolerance and treatment strategy.

BACKGROUND: In end-stage renal disease (ESRD) patients, hepatitis C virus (HCV) eradication improves patient and graft survival. AIM: To determine optimal use of erythropoietin (EPO) and ribavirin, to compare ribavirin concentrations with those of HCV patients having normal renal function and to evaluate sustained virological response (SVR) in a prospective observatory of ESRD candidates for renal transplantation. METHODS: Thirty-two naïve patients were treated with Peg-IFN-α2a and ribavirin. Two different schedules of ribavirin and EPO administration were used: starting ribavirin at 600mg per week and adapting EPO when haemoglobin (Hb) fell below 10g/dL (adaptive strategy) or starting ribavirin at 1000mg per week while increasing EPO from the start of treatment (preventive strategy). RESULTS: Patients treated with the adaptive strategy had lower median Hb levels (9.6 vs. 10.9g/dL, P=0.02) and more frequent median Hb levels below 10g/dL (58 vs. 5%, P=0.0007) despite lower median ribavirin doses (105 vs. 142mg/day, P<0.0001) than patients treated with the preventive strategy. There was a trend for more frequent transfusion in patients treated with the adaptive strategy than in patients treated with preventive strategy (50 vs. 20%, P=0.08). Compared to patients with normal renal function, ESRD patients had lower ribavirin concentrations during the first month (0.81 vs. 1.7mg/L, P=0.007) and similar concentrations thereafter. SVR was reached in 50%. CONCLUSIONS: Pegylated interferon (Peg-IFN) and an adapted schedule of ribavirin are effective in ESRD patients. Increasing EPO from the start of treatment provides better haematological tolerance. The optimal dosage of ribavirin remains unresolved, in light of frequent side effects.

Characterization of the porcine transferrin gene (TF) and its association with disease severity following an experimental Actinobacillus pleuropneumoniae infection.

Transferrin (TF)-mediated provision of iron is essential for a productive infection by many bacterial pathogens, and iron-depletion of TF is a first line defence against bacterial infections. Therefore, the transferrin (TF) gene can be considered a candidate gene for disease resistance. We obtained the complete DNA sequence of the porcine TF gene, which spans 40 kb and contains 17 exons. We identified polymorphisms on a panel of 10 different pig breeds. Comparative intra- and interbreed sequence analysis revealed 62 polymorphisms in the TF gene including one microsatellite. Ten polymorphisms were located in the coding sequence of the TF gene. Four SNPs (c.902A>T, c.980G>A, c.1417A>G, c.1810A>C) were predicted to cause amino acid exchanges (p.Lys301Ile, p.Arg327Lys, p.Lys473Glu, p.Asn604His). We performed association analyses using six selected TF markers and 116 pigs experimentally infected with Actinobacillus pleuropneumoniae serotype 7. The analysis showed breed-specific TF allele frequencies. In German Landrace, we found evidence for a possible association of the severity of A. pleuropneumoniae infection with TF genotypes.

Transient correction of the basic defect in sweat glands in an individual with cystic fibrosis carrying the complex CFTR allele F508del-R553Q.

The molecular pathology of mutant F508del CFTR is partially corrected in vitro by the secondary amino acid substitution R553Q in the ABC signature motif. An individual with the CFTR genotype R553X/F508del-R553Q showed the typical symptoms and electrophysiological anomalies of cystic fibrosis in the airways and intestine. Sweat chloride concentrations were normal early in life, but were later raised into the range that is diagnostic for cystic fibrosis, suggesting that R553Q could temporarily correct the basic defect in sweat glands. R553Q caused a delay in diagnosis because of false negative sweat tests but was not a disease reverting suppressor mutation as had been inferred from cellular models.

Expression levels of FAS are regulated through an evolutionary conserved element in intron 2, which modulates cystic fibrosis disease severity.

We have analyzed frequent naturally occurring variants in the autogene FAS in two independent cystic fibrosis (CF) patient populations. Analysis of FAS expression levels from intestinal epithelial biopsies from 16 unrelated F508del-CFTR homozygotes showed a correlation between FAS intron 2 SNP rs7901656 and signals for Affymetrix GeneChip U133 Plus 2.0 probeset 204781_s_at consistent with a dominant model (P=0.0009). Genotype and haplotype analysis at six informative SNPs spanning the FAS gene locus was carried out on 37 nuclear families representing extreme clinical phenotypes that were selected from the European CF Twin and Sibling Study population of more than 300 affected sibling pairs. Case-control comparison of the haplotype composed of rs2296603-rs7901656-rs1571019 encompassing intron 2 of FAS reached significance (P=0.0246). Comparative phylogenetic analysis and functional annotation of the FAS intron 2 sequence revealed a conserved non-coding sequence surrounding rs7901656 and predicted binding sites for four transcription factors whereby the binding site of c-Rel is altered by rs7901656. Taken together, these findings from two independent CF patient cohorts indicate that allelic variants within FAS intron 2 alter FAS gene expression and that these functional variants modulate the manifestation of CF disease.

Diversity of the basic defect of homozygous CFTR mutation genotypes in humans.

BACKGROUND: Knowledge of how CFTR mutations other than F508del translate into the basic defect in cystic fibrosis (CF) is scarce due to the low incidence of homozygous index cases. METHODS: 17 individuals who are homozygous for deletions, missense, stop or splice site mutations in the CFTR gene were investigated for clinical symptoms of CF and assessed in CFTR function by sweat test, nasal potential difference and intestinal current measurement. RESULTS: CFTR activity in sweat gland, upper airways and distal intestine was normal for homozygous carriers of G314E or L997F and in the range of F508del homozygotes for homozygous carriers of E92K, W1098L, R553X, R1162X, CFTRdele2(ins186) or CFTRdele2,3(21 kb). Homozygotes for M1101K, 1898+3 A-G or 3849+10 kb C-T were not consistent CF or non-CF in the three bioassays. 14 individuals exhibited some chloride conductance in the airways and/or in the intestine which was identified by the differential response to cAMP and DIDS as being caused by CFTR or at least two other chloride conductances. DISCUSSION: CFTR mutations may lead to unusual electrophysiological or clinical manifestations. In vivo and ex vivo functional assessment of CFTR function and in-depth clinical examination of the index cases are indicated to classify yet uncharacterised CFTR mutations as either disease-causing lesions, risk factors, modifiers or neutral variants.

[Endothelin-1 and cardiovascular diseases]. / Endothéline-1 et pathologies cardiovasculaires.

INTRODUCTION: Endothelins are peptides released from endothelial cells. According to both their structure and receptor affinity, three isoforms may be identified. Endothelin-1 is secreted abluminally by endothelial cells, and binds ETA and ETB2 receptors expressed on vascular smooth muscle cells, and ETB1 expressed on endothelial cells. ETA and ETB2 receptors stimulation induces smooth muscle contraction and proliferation, whereas ETB1 receptors stimulation induces relaxation. CURRENT KNOWLEDGE AND KEY POINTS: Endothelin-1 plays an important role in maintaining peripheral vascular tone and systemic blood pressure. It is recognized to have a role in various diseases associated with vasoconstriction and vascular hypertrophy. FUTURE PROSPECTS AND PROJECTS: Recent development of endothelin receptor antagonists seems promising for the treatment of heart failure and systemic hypertension, with interesting results obtained from short-term clinical trials. However, better evaluation of these drugs requires further long-term studies regarding not only the above mentioned diseases but also ischemic heart disease or pulmonary hypertension. Endothelin antagonists are therefore new therapeutic agents able to inhibit a vasoconstricting system that has been recently discovered. Results of ongoing clinical studies are awaited with interest.

Effect of topical vasodilators on gastroepiploic artery graft.

BACKGROUND: Mobilization of the gastroepiploic artery (GEA) often results in a vasospasm with reduction of early graft flow. In order to prevent or suppress this highly reactive artery's spasm, we have compared the effect of 4 vasodilators, used in external application to prepare the GEA graft, prior to myocardial revascularization. METHODS: WE performed a double-blind clinical study to compare the effects of external application of vasodilators on gastroepiploic artery grafts. Fifty patients, whose gastroepiploic artery was used for coronary artery bypass grafting, were randomized into 5 groups of 10 patients. Gastroepiploic artery free flow and hemodynamic measurements were evaluated immediately after harvesting, before any pharmacological manipulation, and 10 minutes after the topical application of vasodilators, respectively: papaverine, linsidomine, nicardipine, glyceryl trinitrate, and normal saline solution. RESULTS: A significant increase in free flow occurred in all groups except for the normal saline solution group with measurements from 26.1+/-3.6 mL/min to 26.4+/-6.5 mL/min; p = 0.9. The most important increase in flow before and after local application occurred with glyceryl trinitrate and papaverine: from 25.5+/-2 mL/min to 50+/-6.1 mL/min (p < or = 0.01) and from 36.8+/-3.2 mL/min to 62+/-7.8 mL/min (p < 0.01) respectively. Nicardipine and linsidomine produced a less significant increase in flow: from 33.1+/-3.6 mL/min to 47.7+/-8.9 mL/min (p < 0.05) and from 28+/-3.8 mL/min to 39.8+/-7.5 mL/min (p < 0.05) respectively. When comparing percentage of flow increase, glyceryl trinitrate appeared to be significantly more efficient than nicardipine and linsidomine (p < 0.01 versus both groups). Although papaverine was more efficient than nicardipine and linsidomine, it did not reach statistical significance. CONCLUSIONS: During intraoperative preparation of the GEA graft, glyceryl trinitrate and papaverine to a lesser extent, used as topical vasodilators, appear to be more efficient in external application to increase the free flow of the GEA.

Frusemide inhibits angiotensin II-induced contraction on human vascular smooth muscle.

AIMS: Frusemide is widely used in the treatment of acute pulmonary oedema, chronic congestive heart failure and, to a lesser degree, in the treatment of hypertension. Evidence suggests that frusenuide exerts an anti-vasoconstrictor effect independent of its diuretic properties. Since angiotensin II is a highly potent vasoconstrictor involved in the pathophysiology of these diseases, we have investigated the effect of frusemide on the contraction elicited by angiotensin II on human internal mammary artery (IMA) and saphenous vein (SV). METHODS: Rings of IMA and SV were suspended for isometric tension recording in organ baths. Concentration-response curves to angiotensin II were performed in the absence (control) or in the presence of frusemide (10(-6) to 10(-3) M). In addition, the effect of frusemide was evaluated after cyclooxygenase inhibition by indomethacin (10(-6) M) and was compared with those of the other loop diuretic bumetanide (10(-4) M). RESULTS: Frusemide induced a concentration-dependent decrease of the contraction elicited by angiotensin II on IMA and SV. On both vessels, the inhibitory effect on the maximal contraction to angiotensin II was significant with concentrations of frusemide from 10(-5) to 10(-3) M. Angiotensin II potency (pD2) was only reduced by 10(-3) M frusemide. The effect of frusemide was not altered in the presence of indomethacin. Bumetanide was less potent than frusemide in inhibiting angiotensin II-induced contractions in both IMA and SV. CONCLUSIONS: Frusemide, at concentrations in the therapeutic range (10(-5) M), inhibits angiotensin II-induced contraction on human isolated IMA and SV. This inhibitory effect is cyclooxygenase independent and appears mediated, at least in part, by inhibition of Na+/K+/2Cl- symport. Reduction in the vasoconstrictor effect of angiotensin 1 may be involved in the therapeutic efficacy of frusemide.

Functional assessment of human femoral arteries after cryopreservation.

PURPOSE: An established method of cryostorage that might preserve the vascular and endothelial responses of human femoral arteries (HFAs) to be transplanted as allografts was studied. METHODS: HFAs were harvested from multiorgan donors and stored at 4 degrees C in Belzer solution before cryostorage. One hundred eleven HFA rings were isolated and randomly assigned to 1 control group of unfrozen HFAs and 2 groups of HFAs cryopreserved for 7 and 30 days, respectively. Cryopreservation was performed in Elohes solution containing dimethyl sulfoxide (1.8 mmol/L), and the rate of cooling was 1.6 degrees C/min, until -141 degrees C was reached. The contractile and relaxant responses of unfrozen and frozen/thawed arteries were assessed in organ bath by measurement of isometric force generated by the HFAs. RESULTS: After thawing, the maximal contractile responses to all the contracting agonists tested (KCl, U46619 [a thromboxane A2-mimetic], norepinephrine, serotonin, and endothelin-1) were in the range of 7% to 34% of the responses in unfrozen HFAs. The endothelium-independent relaxant responses to forskolin and verapamil were weakly altered, whereas the endothelium-independent relaxant responses to sodium nitroprusside were markedly reduced. Cryostorage of HFAs also resulted in a loss of the endothelium-dependent relaxant response to acetylcholine. The vascular and endothelial responses were similarly altered in the HFAs cryopreserved for 7 and 30 days. CONCLUSION: The cryopreservation method used provided a limited preservation of HFAs contractility, a good preservation of the endothelium-independent relaxant responses, but no apparent preservation of the endothelium-dependent relaxation. It is possible that further refinements of the cryopreservation protocol, such as a slower rate of cooling and a more controlled stepwise addition of dimethyl sulfoxide, might allow better post-thaw functional recovery of HFAs.

Glibenclamide inhibits thromboxane A2-induced contraction in human internal mammary artery and saphenous vein.

Glibenclamide, like other hypoglycemic sulfonylurea derivatives, is a potent blocker of ATP-regulated K+ channels. In addition, it is reported to inhibit prostanoid-induced contractions of isolated vascular smooth muscle from different animal species. We investigated the effect of glibenclamide on the thromboxane A2-mimetic U-46619 (9,11-dideoxy-9alpha,11alpha-methanoepoxy-prostaglandin F2alpha)-induced contractions in human isolated internal mammary arteries and saphenous veins. In the two vascular preparations, glibenclamide (3, 10 and 30 microM) caused a concentration-dependent shift to the right of the U-46619 contraction-response curve with a reduction, at the highest concentrations, in the maximal responses. This inhibitory effect appears selective for thromboxane A2-induced contractions since glibenclamide (30 microM) did not alter the contraction of internal mammary arteries in response to norepinephrine and of saphenous veins in response to 5-hydroxytryptamine (5-HT) and endothelin-1. However, glibenclamide reduced the endothelin-1-induced contraction in internal mammary arteries. The endothelin-1-induced contractions were similarly inhibited by GR 32191 ([1R-[1alpha(Z),2beta,3beta,5alpha]]-(+)-7-[5-([1,1'-b iphenyl]-4-ylmethoxy)-3-hydroxy-2-(1-piperidinyl)cyclopentyl]-4-++ +heptonoic acid, a thromboxane A2 receptor antagonist. These results suggest that glibenclamide also reduced the endothelin-1-induced contractions by inhibiting a thromboxane A2 receptor-mediated component of the contraction elicited by this peptide. In conclusion, glibenclamide clearly appears to exert a specific inhibitory influence on prostanoid-induced contractions in human internal mammary arteries and saphenous veins.

[Macrolides and drug interactions: review of the literature]. / Macrolides et interactions médicamenteuses: revue de la littérature.

Clarithromycin, azithromycin and dirithromycin have recently been introduced in France. We list the different drug-interactions with these three new drugs and with erythromycin, josamycin, roxithromycin, midecamycin and spiramycin.

Simultaneous determination of zolpidem and zopiclone in human plasma by gas chromatography-nitrogen-phosphorus detection.

A simple, specific and selective method for the simultaneous determination of zolpidem and zopiclone in human plasma is described. After a liquid-liquid extraction, the extract is injected into a capillary gas chromatograph with an OV-1 fused-silica column coupled to a nitrogen-phosphorus detector. The detection limits are 1 and 2 ng/ml for zolpidem and zopiclone, respectively. The method described is reproducible and linear over a range of concentrations, rendering it suitable for use for pharmacokinetic studies or toxicological evaluations. Absolute identification of the chromatographed compounds is accomplished by gas chromatography--mass spectrometry in both electron-impact and positive-ion chemical ionisation modes.

Terapia desensibilizante cervical: efectos de los cambios en la dieta e higiene bucal / Cervical sensitizing dicrease therapy: effects of diet and bucal hygiene changes

Una terapia conservadora cervical fue estudiada en 20 pacientes que presentaban sensibilidad cervical en caninos y premolares, los cuales fueron evaluados con estímulos táctiles y térmicos y sometidos a cambio de higiene bucal y dieta. Después de 60 días los datos obtenidos revelan una disminución del 19 por ciento de sensibilidad cervical de las piezas en estudio

[Reinforced glass ionomer restorations in modified Class II cavities]. / Restauraciones de vidrio ionomero reforzado en cavidades Class II modificadas.

We report a conservative treatment for superficial approximal caries which consist in a diagonal approach of the lesion, in order to preserve a significant amount of sound tooth and the use of a new glass ionomer cement reinforced with silver particles (Cermet cement) as restorative material. Following the X-ray diagnosis of incipient caries, the new material was placed on the proximal area, combined with the use of a light-cured composite resin in the occlusal surface, where the cavity design was started. The advantages and difficulties of the technique and the main characteristics of Cermet Cement are described in the present article.