[Estimation of the glomerular filtration rate in elderly inpatients: comparison of four methods]. / Quelle méthode d'évaluation de la fonction rénale utiliser chez le sujet âgé hospitalisé en unité de court séjour gériatrique ? Comparaison de quatre méthodes.

PURPOSE: High variability has been observed in the estimation of the glomerular filtration rate (GFR) in older patients, according to the formula used and no single formula has been recommended to date. The aim of this study was to quantify the precision and accuracy of the GFR estimated by means of three formulas and the measurement of cystatin C. METHODS: This prospective study was conducted in an acute care geriatric unit. Participants were patients, aged 70 years and over, having a possible 24-hour urine collection. The GFR was estimated using the Cockroft-Gault (CG), the Modification of Diet in Renal Disease (MDRD), and the Creatinine Clearance (Cl-Cr) formulas. The serum level of cystatin C was also measured. RESULTS: Eighty-one patients were included in the study. CG formula underestimated the GFR by a mean difference of 8.65 ml/min, compared with MDRD formula. Cl-Cr underestimated the GFR by a mean difference of 7.56 ml/min, compared with CG formula, and by a mean difference of 16.79 ml/min, compared with the MDRD formula. The degree of discrepancy between CG and Cl-Cr estimates, and between Cl-Cr and MDRD estimates decreased as the estimated GFR approached normal values. MDRD best matched the measurement of cystatin C, followed by CG and Cl-Cr (Kappa coefficient=0.43, 0.22 and 0.16, respectively). CONCLUSION: Our study confirms the high variability of GFR in older patients and particularly in those with abnormal renal function, depending on the formula used. Serum cystatine C level and MDRD formula appear to be the most concordant estimates of GFR in this population.

Timing of nephrology referral: influence on mortality and morbidity.

To assess the influence of the timing of nephrology referral on the short- and long-term outcome of hemodialysis patients, we retrospectively studied 309 patients who had end-stage renal failure and entered the chronic hemodialysis program in Sainte-Marguerite University Hospital between January 1, 1989, and December 31, 1996. We excluded from the analysis five patients without available data on referral pattern and 34 patients with irreversible acute renal failure. Of the remaining 270 patients, 177 patients (58%) had an early referral (ER) 16 or more weeks before the start of dialysis, and 93 patients (31%) had a late referral (LR) of less than 16 weeks before dialysis. Short-time morbidity (initial emergent dialysis, pulmonary edema, severe hypertension, temporary vascular access placement for first dialysis, prolonged initial hospitalization) was significantly more frequent in LR patients. Long-term evolution (mean follow-up, 26.5 +/- 26 months) did not differ between the two groups. The number of days of hospitalization per patient-year at risk beyond the third month was 21.5 +/- 33.7 days for ER and 21.1 +/- 36 days for LR patients. Survival analysis showed no difference between the two groups: 3-month survival rates were 96% in both groups, 1-year survival rates were 90% in the ER and 89% in the LR group, and 5-year survival rates were 52% in the ER and 56% in the LR group. In a Cox hazards regression model, referral pattern was not associated with a greater risk for death. In conclusion, delayed nephrology referral generated strikingly greater initial morbidity, but long-term outcome of hemodialysis patients was not modified by delayed nephrological care.

Abnormal calcitonin basal levels and pentagastrin response in patients with chronic renal failure on maintenance hemodialysis.

Hypercalcitoninemia has been reported in renal failure. Using a specific monomeric calcitonin (CT) immunoassay, we measured CT levels in 154 hemodialyzed patients. The relationship between CT and serum intact parathyroid hormone (PTH), gastrin, alkaline phosphatases, phosphate and calcium was studied. The pentagastrin test was performed in 26 patients exhibiting basal hypercalcitoninemia. Basal CT levels over 5.7 pmol/l (20 ng/l) were found in 25.3% of the patients and values higher than 26 pmol/l (90 ng/l) in 7.8%. Although CT is cleared by hemodialysis, post-dialysis CT levels either were unchanged or increased as compared with pre-dialysis values. This suggests that hypercalcitoninemia is not related to a decreased renal clearance, and that hemodialysis induces a specific regulatory pathway. None of the parameters studied were found to explain high CT levels. Of the patients with hypercalcitoninemia, 11.5% exhibited abnormal CT response to pentagastrin but no relationship between CT and phosphate, calcium and PTH levels was evidenced. Our findings confirm high CT monomer levels in renal failure. As there was no correlation with parameters classically involved in CT regulation, its physiological significance remains unclear. Abnormal CT response to pentagastrin raises the problem of its specificity as a tumoral marker with regard to medullary thyroid carcinoma.

Is hepatitis C virus-RNA detection by nested polymerase chain reaction clinically relevant in hemodialysis patients?

We have prospectively studied in hemodialysis (HD) patients the evolution of hepatitis C virus (HCV) viremia and the putative relationships between the viremia and the biological markers of liver disease. For each of 22 HD patients having detectable antibodies to HCV (anti-HCV+), we looked four times for serum HCV-RNA by nested PCR (N-PCR), in April and November 1992, November 1993 and May 1994. We checked the transaminases (Trans) and the gamma glutamyl transpeptidase (gamma(GT)) levels on the same day as blood tests for the N-PCR. Abnormal Trans or gamma(GT)++ values were considered if they exceeded the upper limit of the normal level for our laboratory. Fifteen patients (68%) were intermittently N-PCR positive (N-PCR+): 3 patients were N-PCR+ at three determinations, 7 were N-PCR+ at two determinations and 5 only one time. Two patients (9%) were always N-PCR+ and five (23%) always negative. No correlation between an abnormal value of either Trans or gamma(GT) and viremia was evidenced at successive determinations. In conclusion, the majority (68%) of the anti-HCV+ patients had intermittent HCV N-PCR+. Among the anti-HCV+ patients, 77% were viremic. Since HCV viremia is often transitory and since there is no correlation between N-PCR positivity and the increase in Trans or gamma(GT) activities, HCV-RNA detection by N-PCR is probably not clinically relevant in anti-HCV+ HD patients.

Maternal influence on growth of laboratory rats.

Data from 2,089 laboratory rats utilized in selection experiments were used to estimate maternal influence on growth from weaning (21 d) to 16 wk of age. Adjustment factors were calculated for the effects of sex, generation, litter size, inbreeding of the dam and inbreeding of the offspring on the body weights. The effect of line of sire was included in the analysis of variance models. Covariances among paternal half-sibs, full-sibs, offspring-dam, and individuals with the same maternal grandsire were equated to theoretical causal components of variance in a series of simultaneous equations. From these, estimates of heritability, maternal influence and other environmental influences on the weights of the animals were calculated. Estimates of additive genetic effects were negative at weaning and increased to positive intermediate values during postweaning growth. Maternal influence due to additive genetic effects was of primary importance at weaning and tended to diminish at later stages of growth. An antagonism was indicated between maternal environment and genes affecting the offspring's growth. Maternal influence is an important factor at weaning and during the postweaning growth of a litter-bearing species such as the laboratory rat.

Factors affecting and prediction of dystocia in Charolais heifers.

Calving difficulty at first and second parturition, using data recorded on 476 purebred Charolais heifers from a ranch in Southeastern Arizona, were analyzed by analysis of variance, step-wise multiple regression and discriminant analysis. Dystocia score (1 = no assistance through 4 = extreme difficulty) was the dependent variable with dam and calf effects independent variables. In this herd, 31.1 and 15.0% of the heifers experienced calving difficulty at first and second parturition, respectively. Birth weight of calf was the most important factor influencing dystocia, accounting for 71 and 61% of the total variation explained by the analysis of variance model when calf effects as well as dam effects were included at first and second parturition. Mean birth weight was 39.0 kg for primiparous heifers and 44.3 kg for second-half cows. A significant increase in dystocia (at both first and second parturition) occurred among male calves with birth weights of 45.5 kg or greater. At first parturition, no significant increase in dystocia occurred among female calves until birth weight exceeded 50 kg. Birth weight was not a significant factor influencing dystocia for female calves at second parturition. Yearling weight of cow and dystocia score of cow's dam were the only significant dam variables, and only at first parturition. Pelvic height measurements did not significantly affect dystocia scores at either parturition. A reasonably accurate prediction of dystocia based on the variables included in this study would be impossible, even if some means were devised to reliably predict birth weight of the calf.

Genetic parameters, maternal ability and related selection criteria for unsupplemented Hereford range cows.

Data on 5,130 unsupplemented Hereford range cattle were used to evaluate genetic and phenotypic parameters of growth to 2 yr of age under extensive range conditions. From those data, records on 769 heifers saved as replacements were used to evaluate the relationship between growth and subsequent productivity expressed as most probable producing ability (MPPA). Variation in weight largely was due to the year effect. Also, age of dam, the interaction between age of dam and year and the regression on day of birth significantly affected weaning weight. Heritabilities among males and females, respectively, were: birth weight, .53 +/- .09 and .52 +/- .09; weaning weight, .05 +/- .03 and .18 +/- .05; 12-mo gain, .24 +/- .10 and .10 +/- .04; 20-mo gain, .62 +/- .18 and .29 +/- .08; 24-mo gain, .45 +/- .16 and .17 +/- .07. The traits evaluated may have been a response to nutritional stress as well as gainability. The genetic correlation between gain from weaning to 12 mo (a period of weight loss) and gain from 12 to 20 mo (greatest weight gain) was -.93 +/- .45. Metabolic processes favoring growth in a good nutritional environment may result in greater weight loss in a stressful nutritional environment. The genetic correlation between a heifer's gain from weaning to 12 mo and her subsequent MPPA was .47 +/- 28, whereas the correlation between gain from 12 to 20 mo and subsequent MPPA was -.55 +/- .23.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C virus infection among chronic dialysis patients in the south of France: a collaborative study.

During the last quarter of 1992, 984 patients from 13 dialysis centers in the Provence-Alpes-Côte-d'Azur region in France participated in a multicenter cross-sectional study to determine the prevalence, the risk factors, and the clinical consequences of infection by the hepatitis C virus (HCV). Serum samples were tested for anti-HCV antibodies using second-generation enzyme-linked immunosorbent assay (ELISA). In the case of a positive result, a combination test was performed using second-generation recombinant immunoblot (RIBA) or direct detection of HCV-RNA by nested polymerase chain reaction (PCR). Collected data included the patient's age, gender, cause of the kidney disease, type of dialysis treatment, number of years on dialysis, weekly dialysis time, drug addiction, co-infection with hepatitis B virus and human immunodeficiency virus (HIV), number of kidney transplants, number of blood transfusions, and history of acute or chronic hepatitis. Chronic HCV infection was detected in 232 (23.6%) patients, whereas only 71 (7.2%) were infected by HBV. Logistic-regression analysis showed that HCV infection was associated with dialysis over a long period, numerous blood transfusions, female gender, kidney grafts, HBV infection, hemodialysis, and acute as well as chronic hepatitis. Multiple-correspondence analysis confirmed that the contamination was both transfusional and nosocomial. These results underscore the need for a strict compliance with "universal precautions" (Centers for Disease Control [CDC], Atlanta) in dialysis units and raise the question as to whether anti-HCV-positive patients should be isolated.

Nucleolus organizer regions in human lymphocytes as studied with premature chromosome condensation.

Non-stimulated human lymphocytes from peripheral blood usually contain only one ring-shaped nucleolus. Polyethyleneglycol-mediated cell fusion with mitotic Chinese hamster ovary cells induces premature chromosome condensation in human lymphocytes. Subsequent silver staining reveals that more than one nucleolus organizer region (NOR) is silver-positive and frequently participates in the formation of "satellite associations". It can therefore be concluded that more than one NOR contributes to the ring-shaped nucleoli of lymphocytes in human peripheral blood and that they may be transcriptionally active. During phytohemagglutinin (PHA) stimulation, the number of silver-positive NORs, the number of nucleoli and the number of chromosomes participating in "satellite associations" increase.

Plasma endothelin in haemodialysis patients treated with recombinant human erythropoietin.

Predialysis plasma endothelin (ET) values were followed during the first 8 weeks of rHuEpo treatment in 12 patients on routine haemodialysis. Mean plasma ET was significantly increased in uraemic patients before rHuEpo (27.9 +/- 11.4 pmol/l), as compared to 40 healthy controls (16.5 +/- 5.7 pmol/l) (P < 0.0001). Under rHuEpo treatment, predialysis values remained unchanged although diastolic blood pressure increased after 2 and 6 weeks. We found no correlation between ET and haemoglobin or blood pressure before or under rHuEpo treatment. These results confirmed the high levels of plasma ET in haemodialysis patients, but no increase was observed during rHuEpo treatment.

Detection of hepatitis C infection by polymerase chain reaction among hemodialysis patients.

One hundred forty-five patients on regular hemodialysis (HD) at our institution were evaluated for the presence of hepatitis C virus (HCV) infection. Forty-three patients (29%) were found to have detectable antibodies to HCV using second-generation enzyme-linked immunosorbent and recombinant immunoblot assays. Forty positive patients (anti-HCV+) and 10 negative patients (anti-HCV-) were tested for direct detection of the HCV genome by the polymerase chain reaction (PCR). Twenty-one anti-HCV+ patients (52%) had detectable RNA HCV in plasma (PCR+). No anti-HCV- patient had viremia. In addition, we compared the 43 anti-HCV+ patients with the 102 anti-HCV- patients for duration of HD, history of blood transfusion, serologic markers of hepatitis B virus, and acute and chronic liver disease. On retrospective univariate analysis, statistically significant associations with anti-HCV+ were duration of HD (P = 0.0001), blood transfusions (P = 0.0005), co-infection with hepatitis B virus (P = 0.01), and acute and chronic liver disease (P = 0.06 and 0.01, respectively). Three significant variables (duration of HD, chronic hepatitis, and blood transfusions) of the multivariate analysis permit the classification of 65% of anti-HCV+ patients and 81% of anti-HCV- patients. In the anti-HCV+ group, when the same parameters were compared in PCR+ or PCR- patients, no statistical difference appeared. These results reveal that 52% of anti-HCV+ HD patients have HCV infection. The clinical consequences of HCV infection in that population are not characterized since no difference has been documented between PCR+ and PCR- results.

[Nasal carriage of Staphylococcus aureus: prevalence in a hemodialysis center and effect on bacteremia]. / Portage nasal de Staphylococcus aureus: prévalence dans un centre d'hémodialyse et influence sur les bactériémies.

We evaluated nasal carriage of Staphylococcus aureus (S. aureus) in 114 hemodialysis patients by performing two nasal swab cultures at a one month interval. The incidence of bacteremia was then followed for one year. Other factors associated with infections in hemodialysis patients, such as diabetes, central venous catheter, and high serum ferritin levels were also evaluated. Nasal carriage of S. aureus was present in 29.8% of patients (34/114). Six S. aureus bacteremia occurred in 6 patients. This represents an annual incidence of 0.058 bacteremia/patient-year. The incidence of bacteremia was higher in patients with S. aureus nasal carriage (0.0945) than in patients without (0.0417), but the difference was not significant. The relative risk (RR) was 2.35. On the contrary, bacteremia were significantly more frequent in patients with diabetes (RR = 11.41; p = 0.004) or in patients with central venous catheter (RR = 14.29; p = 0.002). In conclusion, in our population, diabetes and central venous catheter are more significant risk factors of bacteriemia than S. aureus nasal carriage.

TT virus infection in French hemodialysis patients: study of prevalence and risk factors.

The TT virus (TTV) is a recently discovered DNA virus which was first identified in patients with non-A to -G hepatitis following blood transfusion. In this study, we tested 150 attendees of two hemodialysis (HD) units of the public hospitals of Marseilles, France, for the presence of TTV genome by using a PCR-based methodology. The overall prevalence of TTV viremia was 28% (compared to 5.3% in blood donors from the same region). We demonstrated the existence of chronic infections and superinfections by strains belonging to different genotypes. The prevalence of infection was higher in patients originating from Africa, in patients with previous blood transfusion or organ transplantation, in patients with antibody to hepatitis B core antigen, and in those with diabetes mellitus. A high prevalence of TTV infection (50%) was also observed in a population of patients with diabetes mellitus but without renal disease. No significant relationship was found between TTV viremia and hepatitis C virus or GB virus C, transaminases, age, sex, and duration of HD treatment. The PCR amplification products (located in open reading frame 1 of the TTV genome) were sequenced. These genomic sequences were submitted to phylogenetic analysis by using the Jukes-Cantor algorithm for distance determination and the neighbor-joining method for tree building. In several instances, sequences from viruses isolated in a HD unit were grouped in the same phylogenetic cluster. These results together with the different distribution of cases in the two HD units suggest there is viral transmission within each.