[Preanalytical variability of parathyroid hormone measurement in dialysis patients; application to Elecsys 2010 (Roche) automate]. / Variabilité préanalytique du dosage de la parathormone chez le patient dialysé; application à l'automate Elecsys 2010 (Roche).

The working group PTH-Vitamin D of the SFBC recently underlined the great intertechnic variability of parathormone (PTH) assays. At the same time, the data of the literature showed an impact of the preanalytic stage, significant and variable according to the automat used. We worked on the automat Roche Elecsys. On quickly centrifuged and decanted samples, the small difference in results between serum and plasma EDTA (6%) is compatible with an indifferent use of the two samples for dialysed patients. The reputation of greater stability on plasma EDTA seems primarily based on studies after decantation of plasma. The extension to a non decanted sample, maintained on primary tube for deferred shipping to the laboratory would require verification. Concerning the serum, on tube with serum separator, after early centrifugation, we checked the stability of the PTH measurement for a delay lower than or equal to 4 hours. For an extrahospital structure of dialysis, in the conditions of an early and an on site centrifugation, this delay allows to defer the transport of the primary closed tube to the laboratory. Contrary to plasma EDTA, the serum also allows simultaneous measurements of other parameters used for the care of the dialysed patients.

Homologous recombination and transposition generate chromosome I neopolymorphism during meiosis in Saccharomyces cerevisiae.

We have studied the meiotic segregation of a chromosome length polymorphism (CLP) in the yeast Saccharomyces cerevisiae. The neopolymorphism frequently observed within the smallest chromosomes (I, VI, III and IX) is not completely understood. We focused on the analysis of the structure of chromosome I in 88 segregants from a cross between YNN295 and FL100trp. Strain FL100trp is known to carry a reciprocal translocation between the left arm of chromosome III and the right arm of chromosome I. PCR and Southern hybridization analyses were performed and a method for the rapid detection of chromosome I rearrangements was developed. Seven chromosome I types were identified among the 88 segregants. We detected 22 recombination events between homologous chromosomes I and seven ectopic recombination events between FL100trp chromosome III and YNN295 chromosome I. These recombination events occurred in 20 of the 22 tetrads studied (91%). Nine tetrads (41%) showed two recombination events. This showed that homologous recombination involving polymorphic homologues or heterologous chromosomes is the main source of neopolymorphism. Only one of the seven chromosome I variants resulted from a transposition event rather than a recombination event. We demonstrated that a Tyl element had transposed within the translocated region of chromosome I, generating mutations in the 3' LTR, at the border between U5 and PBS.

Two-dimensional gel analysis of the proteome of lager brewing yeasts.

Modern lager brewing yeasts used in beer production are hybrid strains consisting of at least two different genomes. To obtain information on the identity of the parental strains that gave rise to industrial lager yeasts, we used two-dimensional (2-D) gel electrophoresis and analysed the proteomes of different Saccharomyces species isolated from breweries. We found that the proteome of lager brewing yeasts and of the type strains of S. carlsbergensis, S. monacensis and S. pastorianus can be interpreted as the superimposition of two elementary patterns. One originates from proteins encoded by a S. cerevisiae-like genome. The other corresponds to a divergent Saccharomyces species whose best representative is a particular S. pastorianus strain, NRRL Y-1551. A map of industrial lager brewing yeasts has been established, with the individual origin of proteins and with identification of protein spots by comparison to known S. cerevisiae proteins. This 2-D map can be accessed on the Lager Brewing Yeast Protein Map server through the World Wide Web. This study provides the first example of the use of proteome analysis for investigating taxonomic relationships between divergent yeast species.

Real-time quantitative PCR detection of genetically modified Maximizer maize and Roundup Ready soybean in some representative foods.

A fast and quantitative method was developed to detect transgenic "Maximizer" maize "event 176" (Novartis) and "Roundup Ready" soybean (Monsanto) in food by real-time quantitative PCR. The use of the ABI Prism 7700 sequence detection system allowed the determination of the amplified product accumulation through a fluorogenic probe (TaqMan). Fluorescent dyes were chosen in such a way as to coamplify total and transgenic DNA in the same tube. Using real-time quantitative PCR, 2 pg of transgenic or total DNA per gram of starting sample was detected in 3 h after DNA extraction and the relative amounts of "Maximizer" maize and "Roundup Ready" soybean in some representative food products were quantified.

[Calcium oxalate lithiasis. Relationship between biochemical risk factors and crystalline phase of the stone]. / Lithiase oxalocalcique. Relation entre facteurs de risque biochimiques et phase cristalline du calcul.

OBJECTIVES: To identify biochemical risk factors specific to each crystalline phase of calcium oxalate (calcium oxalate monohydrate and calcium oxalate dihydrate) in order to allow more specific medical management of calcium oxalate stones and better prevention of recurrences. MATERIAL AND METHODS: The authors compared the urine biochemistry (morning and 24-hour) of 19 patients with stones containing more than 95% of calcium oxalate monohydrate with those of 16 patients with stones containing more than 60% of calcium oxalate dihydrate (calcium phosphate < 12%). RESULTS: Urinary calcium, expressed as excretion rate and as concentration, and the calcium/citrate ratio were significantly higher in the calcium oxalate dihydrate group than in the calcium oxalate monohydrate group: (9.2 +/- 3.8 mmol/24 h versus 4.4 +/- 1.7 mmol/24 h); (4.9 +/- 2.1 mmol/l versus 2.4 +/- 1.1 mmol/l); (3.3 +/- 1.6 versus 1.6 +/- 0.7). The mean pH of the morning urine was lower in the calcium oxalate monohydrate group, just below the cut-off value of 5.5. CONCLUSION: There is a strong correlation between predominantly calcium oxalate dihydrate stones and hypercalciuria or calcium/citrate ratio > 3. The close relationship between urine biochemistry and crystalline phases of calcium oxalate confirms the clinical value of morphoconstitutional analysis of urinary stones. Identification of risk factors, based on stone analysis, allows more specific medical management of the stones and, in the longer term, better prevention of recurrences.

A family of laboratory strains of Saccharomyces cerevisiae carry rearrangements involving chromosomes I and III.

In order to study meiotic segregation of chromosome length polymorphism in yeast, we analysed the progeny of a cross involving two laboratory strains FL100trp and YNN295. Analysis of the parental strains led us to detect an important length polymorphism of chromosomes I and III in FL100trp. A reciprocal translocation involving 80 kb of the left arm of chromosome III and 45 kb of the right arm of chromosome I was shown to be the cause for the observed polymorphism in this strain. The characterization of the translocation breakpoints revealed the existence of a transposition hot-spot on chromosome I: the sequence of the translocation joints on chromosomes I and III suggests that the mechanism very likely involved homologous recombination between Ty2 transposable elements on each chromosome. Analysis of FL100, FL200 and FL100trp ura, which are related to FL100trp, shows that this reciprocal translocation is present in some of the strains of the FL series, whereas the parental strain FL100 does not carry the same rearrangement. We evidenced instead the duplication of 80 kb of chromosome III on chromosome I and a deletion of 45 kb of the right arm of chromosome I in this strain, indicating that secondary events might have taken place and that the strain currently named FL100 is not the common ancestor of the FL series.

Direct detection of viable bacteria, molds, and yeasts by reverse transcriptase PCR in contaminated milk samples after heat treatment.

A fast, sensitive, and target contaminant-modulable method was developed to detect viable bacteria, molds, and yeasts after heat treatment. By reverse transcriptase PCR with elongation factor gene (EF-Tu or EF-1 alpha)-specific primers, the detection level was 10 cells ml of milk-1. The simplicity and rapidity (4 h) of the procedure suggests that this method may be easily transposable to other foods and other contaminants.

Identification of cis-elements regulating the expression of an Arabidopsis histone H4 gene.

Protein-DNA interactions in the proximal region of an Arabidopsis H4 histone gene promoter were analyzed by DMS in vivo footprinting combined with LMPCR amplification. Interactions were identified over six particular sequence motifs, five of which were previously shown to bind proteins in maize histone H3 and H4 promoters and are commonly found in the corresponding regions of other plant histone gene promoters. These motifs are located within a 126 bp fragment which was previously shown to confer preferential expression in meristems of transgenic plants. The contribution of each cis-element to the overall expression level and specificity was investigated by testing individual or combined mutations in transgenic Arabidopsis plants. All five motifs behaved as positive cis-elements of unequal strength. The GCCAAT-like sequence GCCACT behaved as a strong positive cis-element but had no influence on the specificity. In contrast, the nonamer AGATCGACG and to a lesser extent the closely linked hexamer CCGTCG proved to be essential for meristem-specific expression. Involvement of the highly conserved histone-specific octamer CGCGGATC in specific expression was revealed at some stages of meristem development. Importance of these three cis-elements, nonamer, hexamer, and octamer, was further confirmed by the fact that combining mutations of two of them either abolished the promoter activity or completely modified the promoter specificity. Mutation of the fifth cis-element, a degenerate copy of the octamer, little perturbed the promoter function. However disruption of both octamers had a dramatic negative effect, thus suggesting that the two copies cooperate to achieve maximal function in the wild-type promoter, possibly by mobilizing the proliferation-specific factors binding to the nonamer and CCGTCG cis-elements.

[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.

Constitutive and cell-division-inducible protein-DNA interactions in two maize histone gene promoters.

Protein-DNA interactions in the promoter regions of two maize histone genes have been analyzed by DNase I and DMS in vivo footprinting combined with LMPCR amplification. Both promoters present a bimodular structure characterized by a proximal cell division-specific set of interactions and a distal region which displays constitutive footprints but enhancement of these footprints upon cell proliferation. The inducible region contains two cis-elements common to all replication-dependent plant histone genes, one of them having previously been shown to be a target for the wheat nuclear protein HBP-2. In the constitutive region, the first demonstration for the existence of a transcription factor binding to the highly conserved plant histone-specific octamer CGCGGATC is provided. Exchange of cell-type-specific factors is postulated to occur at that site. Additional immediate upstream constitutive elements binding regulatory proteins include a degenerate octameric sequence, a CCAAT-box, a CACCC sequence and composite ACGTCA/ACGTGG hexameric sequences binding HBP-1-related trans-acting factors. The close proximity of these elements within the constitutive region and the redundancy of some of them suggest complex cooperation and competition mechanisms contributing to achieve the final expression level and likely also to mediate the interplay between constitutive and inducible factors.

Nuclease sensitivity and functional analysis of a maize histone H3 gene promoter.

A 1 kb region of a maize H3 histone gene promoter has been analysed at a structural and functional level. Micrococcal nuclease digestion of isolated nuclei showed that the promoter region is organized into nucleosomes but a zone extending over approximately one nucleosome (20 to 230 bp upstream of the TATA box) displays remarkable accessibility to digestion. Three DNase I-hypersensitive sites were found within this zone at the vicinity of consensus sequences, some of which are already known to act as cis elements. This promoter region is able to direct faithful expression of the GUS reporter gene in meristematic tissues of transgenic tobacco plants.

Pharmacokinetics of cadralazine and its hydrazino-metabolite in patients with renal impairment after repeated administration of 5 mg once daily.

Since the hydrazino-pyridazine metabolite of cadralazine, CGP 22 639 is believed to contribute to the activity of the drug, its pharmacokinetics and that of cadralazine were investigated in 8 hypertensive patients with renal impairment. The creatinine clearance (CLcr) of patients ranged from 10 to 60 ml/min. The concentrations of cadralazine in plasma and urine, and of CGP 22 639 (plus its possible hydrazones) in plasma were measured after single and repeated administration of 5 mg of cadralazine once daily. A hypotension possibly linked to cadralazine treatment was recorded on day 3 for the patient with CLcr = 10 ml/min. Metabolite concentrations were found to be at least twice as high as in other patients indicating that in this patient, the daily dose of 5 mg was probably too high. The pharmacokinetics of cadralazine were not modified by repeated administration. The drug and its metabolite were eliminated more slowly in patients with low creatinine clearance. The t1/2 of CGP 22 639 was about twice the t1/2 of the unchanged drug. In patients whose CLcr ranged from 19-37 ml/min the mean accumulation factor of apparent CGP 22 639 was 1.7 times that of the unchanged drug. It shows that the apparent CGP 22 639 accumulated more than the unchanged drug. A starting daily dose of 2.5 mg of cadralazine in patients with CLcr < 40 ml/min appears to be suited to take into account the pharmacokinetics of CGP 22 639. This dose can be increased by 2.5 mg steps if the antihypertensive effect is not sufficient (maximum dose with CLcr < 40 ml/min: 10 mg).(ABSTRACT TRUNCATED AT 250 WORDS)

[Treatment of chronic renal insufficiency: hemodialysis at a center or continuous ambulatory peritoneal dialysis? Comparative retrospective study of the success of both methods]. / Le traitement de l'insuffisance rénale chronique: hémodialyse en centre ou dialyse péritonéale continue ambulatoire? Etude comparative rétrospective du succès des deux méthodes.

In a retrospective study, the authors analyse the dialysis-technique success rate in 276 chronic renal patients. 137 patients have been treated with in-center Hemodialysis (CHD) since 1972, 139 patients with Continuous Ambulatory Peritoneal Dialysis (CAPD) since 1978. The 6-year technic success rate reaches 28% in CAPD and 31% in CHD (not statistically significant). The risk factors influence the technic-success rate of both methods in the same way. The results suggest that in the analysed patients CAPD is at least as effective as CHD at maintenance in the technic.

[Influence of experience on the success of the treatment of chronic kidney failure by continuous ambulatory peritoneal dialysis compared with hemodialysis at a center]. / Influence de l'expérience sur le succès du traitement de l'insuffisance rénale chronique par dialyse péritonéale continue ambulatoire comparativement à l'hémodialyse en centre.

Experience influence on treatment success of renal chronic failure by continuous ambulatory peritoneal dialysis comparatively to hemodialysis in center is estimated by the probability variation of still being in dialysis techniques. The retrospective study was realized in 276 dialysed patients who were taken over from 1972 to April 1989. In this population, there isn't any significant difference between the probability to stay in ambulatory peritoneal dialysis or in hemodialysis in center. But, if the study is realizing from the 4 years which followed the technique introduction in the center, the success probability at 30 months, remains the same for hemodialysis in center whether the technique has began in 1972 or 1976, whereas for continuous ambulatory peritoneal dialysis, this probability raises from 52% to 72% if it begins after 1982. Ambulatory peritoneal dialysis treated patients would be maintained more longer in their system than hemodialysis patients. Those results are explaining by prevention of the peritonitis thanks to technological progress and the early prevention of possible complications.

[Daily hemodialysis of ultra-short duration with non-traumatic vascular access. Two cases]. / Expérience d'hémodialyse quotidienne ultra-courte avec abord vasculaire atraumatique. A propos de deux cas.

The authors report their experience on treating two patients, suffering end-stage renal disease, by daily hemodialysis of ultra-short duration with a non-traumatic vascular access. 90 minutes dialysis are realized 6 days a week. Clinical tolerance is excellent and patients' adhesion is satisfactory. However, despite reutilization of the dialyzer, the method remains costly.

Continuous ambulatory peritoneal dialysis (CAPD) or center hemodialysis? Retrospective evaluation of the success of both methods.

In a retrospective study, the authors analysed the dialysis-technique success rate in 276 chronic renal patients. Of these, 137 patients have been treated with in center hemodialysis (CHD) from 1972 to 1989 and 139 with continuous ambulatory peritoneal dialysis (CAPD) from 1978 to 1989. The six-year technique success rate was 28% in CAPD and 31% in CHD (statistically not significantly different). Various risk factors influence the technique-success rate of both methods in the same way. The results suggest that in our center CAPD is as effective as CHD in the treatment of patients with end-stage renal failure.

[Local immunologic reactions induced by CAPD]. / Les réactions immunologiques locales induites par la DPCA.

During CAPD, the peritoneal cavity is submitted to situations such as the accidental bacterial contaminations and the continuous presence of dialysate, which stimulate immunological factors. The antibacterial defenses include opsonins and cells. Only IgG and fibronectin are present in the peritoneal effluent but they are diluted by the dialysate. Macrophages represent 70 to 80% of the peritoneal cells. Beside good phagocytic capacity, some may have a defective bactericidal activity. The continuous presence of dialysate leads to a chronic local inflammation. Macrophages and lymphocytes will synthesize IL-1, PGE2 and IFN-Y. These substances generate movement, attachment and proliferation of fibroblasts in the peritoneal submesothelial tissue, resulting in progressive fibrosis. This fibrosis, generally asymptomatic, may be responsible for loss of Ultrafiltration (UF) and Sclerosing Encapsulating Peritonitis (SEP).