[Severe pruriginous acne in dialysed renal failure. Diagnostic difficulties and efficacy of isotretinoin]. / Acné prurigineuse grave chez l'insuffisant rénal dialysé. Difficultés diagnostiques et efficacité de l'isotrétinoïne.

INTRODUCTION: The occurrence of acne in dialysed renal failure patients has rarely been reported and the clinical characteristics and therapeutic issues rarely studied in these patients. CASE REPORTS: Two men and two women, 33 to 56 years-old, with chronic renal failure and no past history of acne, developed severe acne under dialysis. The acne was excoriated in all cases and associated with prurigo-like lesions and intense pruritus, which made diagnosis difficult. Acne was profuse on the face and the trunk, but also on the neck (1 case) and the upper limbs (2 cases). No patient was taking acne-inducing substances. Various to therapies attempting to control pruritus were ineffective. However, anti-acne treatments (cyclines associated with local tretinoin in 1 case and oral isotreninoin in 3 cases) led to complete regression of the acne, pruritus and the prurigo-like lesions without relapse after a follow-up time of 4 months to 2 years. DISCUSSION: Pruritus is frequent during renal failure. However, the occurrence of unexplained acne has only rarely been reported. Our patients' clinical picture was original, characterized by the late development, under dialysis, of severe and pruriginous acne, the pathogenesis of which is unknown. Because of the clinical and therapeutic implications (impaired quality of life, pigmentation or scarring and remarkable efficacy of oral isotretinoin) this clinical picture merits more attention, and the modalities for the prescription of isotretinoin in this context should be defined.

A promoter identified in the 3' end of the Ac transposon can be activated by cis-acting elements in transgenic Arabidopsis lines.

In experiments directed to develop a promoter trap strategy in Arabidopsis, using a Ds chimaeric element containing a promoterless beta-glucuronidase (GUS) gene, we identified a promoter in the 3' end region of the Ac transposable element. The promoter initiates most of the transcripts at coordinate 4250 in the Ac sequence and is oriented towards the internal part of the element. When fused to a promoterless GUS gene, the promoter allows transient expression in Arabidopsis leaves. After stable integration into the Arabidpsis genome, no GUS activity was observed in most of the transformed lines analysed. Only two of them exhibited different tissue-specific GUS expression. When a CaMV 35S promoter was introduced into the transformation vector, downstream to the reporter gene, a high level of GUS activity was observed in all the transformants. These results strongly suggest that the promoter is not normally expressed at a significant level in Arabidopsis transformed lines except when activated by neighbouring cis-acting enhancer elements. This opens an interesting possibility for using this promoter to develop 'enhancer trap' strategies in Arabidopsis. Since only one Ac transcript, initiating in the 5' end region of the element has been reported to date in maize, the putative biological function of the promoter remains an open question.

[Determination of Hb A1c in chronic renal failure. Contribution of new methodologies]. / Dosage de l'HbA1c chez l'insuffisant rénal chronique. Apports des nouvelles méthodologies.

Carbamylated haemoglobin arises from the non-enzymatic modification of haemoglobin by cyanate derived from spontaneous dissociation of urea. We studied the in vitro and in vivo interference of carbamylated haemoglobin in the assay of HbA1c by CLHP (ion exchange), affinity chromatography (IMX, Abbott) and immunoturbidimetry (Tina-Quant, Boehringer). For patients with chronic renal failure on continuous ambulatory peritoneal dialysis, CLHP assay of HbA1c gave an error of about +0.35% per 10 mmol/L of urea serum concentration. The IMX and especially Tina-Quant assays for measuring HbA1c were not sensitive to cyanate interference and constitute interesting alternatives for monitoring glycaemic balance in patients with chronic renal failure.

Athila, a new retroelement from Arabidopsis thaliana.

An analysis of Arabidopsis thaliana heterochromatic regions allowed the identification of a new family of retroelements called Athila. These 10.5 kb elements, representing ca. 0.3% of the genome, present several features of retrotransposons and retroviruses. Athila elements are flanked by 1.5 kb long terminal repeats (LTR) that are themselves bounded by 5 bp perfect inverted repeats. These LTRs start and end with the retroviral consensus 5'TG...CA3' nucleotides. A putative tRNA-binding site and a polypurine tract are found adjacent to the 5' and 3' LTR respectively. The central domain is composed of two long open reading frames (ORFs) of 935 and 694 amino acids. Despite several indications of recent transposition activity, the translation of these ORFs failed to reveal significant homology with proteins associated to retrotransposition. We suggest that the Athila family could result from the transduction and dispersion of a cellular gene by a retrotransposon.

Prognostic factors in CAPD patients: a retrospective study of a 10-year period.

A prognostic study was retrospectively performed on a cohort of 201 ESRD patients having started CAPD in one single centre between 1983 and 1993 (mean follow-up 24 months). At the end of the study 74 patients had died, 63 were transplanted, and 19 had been transferred to another dialysis modality. The purpose of the study was to estimate patient and technique survivals according to clinical and biological variables recorded at the beginning of the treatment. The authors decided to focus on the possible prognostic role of urea kinetic parameters which are still controversial in the literature. Concerning patient survival, the Cox proportional hazards model selected seven prognostic factors, including urea Kt/V (relative risk = 1.69). The division of the study group according to three levels of Kt/V (< or = 1.7, between 1.7 and 2.2, and > 2.2) allowed us to estimate 1.7 as an index of an adequate CAPD prescription. NPCR at the limit of significance for patient survival was clearly a prognostic factor for technique survival (relative risk = 2.50). Creatinine clearance was closely linked to both technique and patient survival (relative risk > 3). These three factors, in addition to the clinical and biological variables generally described in the literature, must be taken into account in the evaluation of a prognosis for CAPD.

[Long term continuous ambulatory peritoneal dialysis: results and limits]. / La dialyse péritonéale continue ambulatoire au long cours: résultats et limites.

Retrospective studies of CAPD show a 50% patient survival at 5 years. There are actually three long term technique limits: UF failure: The diagnosis is made clinically and by peritoneal permeability tests. The use of new osmotic agents should improve this problem. Inadequate dialysis seems more related to the low dialysate flow rather than to the peritoneal membrane. The increase of dialysate volumes or the switch to Automated PD leads to better clearances. The peritoneal membrane lesions are generated by the use of an aggressive dialysate. In order to protect the membrane, new biocompatible solutions are under evaluation.

Bioreactor studies on the effect of dissolved oxygen concentrations on growth and differentiation of carrot (Daucus carota L.) cell cultures.

A bioreactor control system was used to investigate the effects of two dissolved oxygen concentrations (10% and 100%) on the growth and differentiation of Daucus carota L. cell cultures. The strategy used allowed the dissolved oxygen concentration to be controlled without the need for changing either the agitator speed or the total gas flow rate. During the proliferation phase, reducing oxygen resulted in a lower growth rate and in a delay in sugar uptake kinetics. Nonetheless, varying levels of oxygen were observed to have no effect on the final dry biomass. The higher alcohol dehydrogenase activity obtained under reduced oxygen conditions suggests that proliferating cultures adapted to the hypoxic environment by inducing alcoholic fermentation. Cell differentiation was highly sensitive to reduced oxygen since under this condition, the somatic embryo production was inhibited by about 75%. Sugar uptake and embryo formation were also delayed.