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Biomedical subjects

C Biosca

Publications and source records attributed to C Biosca.

13 recordsLinked to original sources
PubMed2000

Are equally spaced specimen collections necessary to assess biological variation? Evidence from renal transplant recipients.

The established method for determining the components of biological variation (BV) requires equispaced time intervals between samplings. In a previous study, we determined BV in renal post transplantation patients, taking advantage of the samples obtained within their clinical treatment protocol (not necessarily equispaced). To confirm the validity of this practice, we sought to determine if the use of varying sampling intervals has an effect on the results obtained in such biological variation studies. The study included two phases: comparison of the results found with identical and non-identical sampling intervals and correlation between the within-subject BV and the length of the sampling interval. There were no differences in within-subject BV between the groups or correlations with sampling intervals for any of the constituents studied. We conclude that samples acquired within established clinical protocols for kidney transplant recipients can be used for estimating BV.

Adult↗
PubMed1998

Effects of polyunsaturated fatty acids on rat glomerulosclerosis induced by hypercholesterolaemic diet.

Association between lipids and renal disease has been reported recently. Its pathogenic mechanisms remain unknown. The aims of this study were to establish: (1) if a cholesterol-rich diet, alone or associated with nephrectomy, produces nephropathy; and (2) if a treatment with omega-3 polyunsaturated fatty acids (PUFA) reduces glomerulosclerotic lesions. Sixty Sprague-Dawley rats were randomized in two different groups: (A) sham operated rats and (B) uninephrectomized rats. Rats in both groups were divided into three subgroups (A1-3, B1-3) according to the diet they were fed: normal chow diet, cholesterol-rich diet (4.5%) or cholesterol-rich diet supplemented with omega-3 PUFA. Twenty weeks later, serum creatinine, creatinine clearance, serum cholesterol, triglycerides, albumin, proteinuria, mesangial cell score and focal glomerulosclerosis were assessed. Results showed that a cholesterol-rich diet significantly increased serum cholesterol, proteinuria and glomerular lesions and decreased creatinine clearance, especially in nephrectomized rats. Glomerular lesions, serum cholesterol and proteinuria ameliorated when cholesterol-rich diet was supplemented with PUFA. Hypertension was noticed only in nephrectomized rats following a normal chow diet. Simple correlation analysis showed that glomerulosclerosis correlated with renal weight, blood creatinine, cholesterol and proteinuria. In spite of some significant differences in urinary prostaglandins, no correlation with glomerular lesions was found. Multiple logistic regression analysis showed that cholesterol and proteinuria were independent risk factors for induction of glomerular sclerosis. In conclusion, a diet rich in cholesterol induces glomerulosclerosis, especially if it is associated with unilateral nephrectomy. Omega-3 PUFA administration reduces serum cholesterol, proteinuria and glomerular injury.

Analysis of Variance↗
PubMed1998

European multicentre evaluation of the Super Aution SA-4220 urinalysis analyser.

A multicentre evaluation of the urine test strip analyser Super Aution-4220 was carried out in six laboratories. The analytical performance of the instrument with regard to imprecision, linearity, detection limit, drift, carry-over and method comparison was studied. Using the Aution stick 8 test strip the pH, glucose, protein, ketones, bilirubin, blood, urobilinogen and leukocyte esterase were analysed. Specific gravity measurements were performed by refractive index method. Within-run and between-run imprecision determined at three levels of analyte were good. No carry-over was observed. Obtained results were linear through all the described analytical range. No significant drift was detected. Method comparison with some quantitative methods was performed and showed a good correlation with most of the analytes. The study of interferences showed minor interferences by common therapeutic drugs with the measurement of some analytes. During the assessment period of about 6 months no breakdown occurred in any laboratory. The Super Aution urine analyser appeared to be a highly automated analyser of urinary test strips. The operation was simple and the maintenance required only a few minutes a day.

Artifacts↗
PubMed1997

Potential interfering substances on Falcor-600 and Dax-48 analytical systems.

The increasing availability and use of automatic analysers in clinical chemistry have revealed a number of endogenous interferences. We evaluated the effect of bilirubin, haemolysis and lipaemia on the Falcor-600 analytical system (Menarini Diagnostics) and the Dax-48 (Bayer Diagnostic). We studied the potential endogenous interferences in the measurement of serum glucose, urea, creatinine, cholesterol, triacylglycerols, total bilirubin, total protein, aspartate aminotransferase, alanine aminotransferase and gamma-glutamyltransferase on both analysers; and albumin, direct bilirubin, uric acid, inorganic phosphorus, iron, calcium, magnesium, chloride, sodium, potassium, alkaline phosphatase, amylase, lactate dehydrogenase and creatine kinase on the Dax-48. We followed the guidelines of the Spanish Society of Clinical Biochemistry and Molecular Pathology. Bilirubin samples were prepared using bovine bilirubin, and studied in the concentration range of 20 to 400 mumol/l. For haemolysis, the pool was spiked with a diluted haemolysate of human red cells to achieve a concentration range of 10 to 120 mumol/l of haemoglobin. Lipaemia was studied using samples spiked with Intralipid, a fat emulsion, at concentrations from 1 g/l to 6 g/l (3 to 18 mumol/l of triacylglycerols).

Animals↗
PubMed1995

Peritoneal transport evaluation in peritonitis: comparison between methods.

Peritoneal dialysis patients may need solute permeability transport evaluation during acute peritonitis. The aim of this study was to assess if the simplified mass transfer coefficient (MTCS) or the peritoneal equilibration test (PET) was equivalent to the complex MTC (MTCX) in solute transport evaluation during acute peritonitis in continuous ambulatory peritoneal dialysis (CAPD) patients. We studied 15 episodes of peritonitis (PTIS). Results were compared to a baseline patient study (PRE) and a control study done 30 days after diagnosis of peritonitis (POST). All peritoneal evaluation methods showed a significant increase in solute transport during acute peritonitis compared to baseline and control studies. There was an acceptable correlation between MTCX and simplified methods including the PET in the baseline and control studies. However, correlation between MTCX and simplified methods decreased during acute peritonitis. Likewise, the PET showed a better correlation with MTCX than MTCS. We conclude that the PET has an acceptable agreement with MTCX even during acute peritonitis, so the PET can be a useful tool in evaluating peritonitis-induced peritoneal permeability changes.

Acute Disease↗
PubMed1993

Mass transfer coefficient: comparison between methods.

The mass transfer area coefficient (MTC) is the best parameter for solute transport evaluation in continuous ambulatory peritoneal dialysis (CAPD) patients. We compared three simplified MTC methods (calculated according Garred, Krediet, or Lindholm) and the peritoneal equilibration test (PET) (Twardowski) to complex MTC (MTCX) (Randerson and Farrell) for urea and creatinine, by means of 29 tests performed in 24 stable CAPD patients. There were no significant differences (paired t-test) between MTCX and each of the simplified MTC, except for creatinine MTC calculated by Krediet's method, which was significantly different (MTCX: 9.36 +/- 4.32, K-MTC: 10.48 +/- 4.55, p < 0.05). Likewise, there was an acceptable correlation between complex MTC and each of the simplified methods including the PET. However, a more detailed study of the MTC's categorizations shows poor agreement with complex MTC categorization. Better results are obtained by PET categorization, which reaches good likelihood ratios either for positive or negative events. We conclude that simplified MTC or the dialysate/plasma ratio at 240 minutes for urea and creatinine has an acceptable correlation with complex MTC and can be useful in clinical practice. There is poor agreement between solute transport categorizations of simplified MTC and complex MTC. There is a better coincidence between the PET (D/P at 240 minutes) and complex MTC categorizations.

Adolescent↗
PubMed1992

Peritoneal function tests: usefulness of simplified methods.

The Peritoneal Equilibration Test (PET) as standardized by Twardowski (T) and simplified Mass Transfer Coefficients (MTC) as per Garred (G) and Krediet (K) have been employed in our patients to assess: 1) the reproducibility of results, 2) correlation between methods, and 3) usefulness of patient categorization by simplified methods in contrast to PET patterns. We have performed 29 standardized PET (Dianeal 2.5%) in 24 stable CAPD patients. We have collected dialysate samples at 0, 30, 60, 120, 180 and 240 minutes. With this data we were able to calculate the dialysate/plasma ratio for PET, MTC as per Garred and MTC as per Krediet. Our results were not significantly different from data reported by the original authors, except for PET D/P urea at 240': 0.91 +/- 0.07(T) vs. 0.87 +/- 0.08 (our), p < 0.05. In our patients, good correlation was found between PET and MTC for urea, creatinine, and glucose, using both formulae (G and K). Patient categorization as High, High Average, Low Average, and Low by MTCs can well predict PET categorization with acceptable sensitivity and good specificity. We conclude there is good reproducibility of the methods. There is also a close correlation between PET, K and G methods for solute transport evaluation and patient categorization. Simplified methods can be substituted for the more complex ones.

Adolescent↗
PubMed1991

Evaluation of the Chem 1 analyzer.

The selective multitest Technicon Chem 1 analyser was evaluated according to the guidelines of the 'Comisión de Instrumentación de la Sociedad Española de Química Clínica', and the protocols of the 'European Committee for Clinical Laboratory Standards' and 'Commission de validation de techniques' of the 'Société Française de Biologie Clinique'. The evaluation was performed in three steps: evaluation in routine conditions, assessment of the interferences and study of practicability. Under routine working conditions, eighteen constituents were studied. Within-run imprecision ranged from 0.6% (CV) for gamma-GT to 4.7% (CV) for AST. Between-run imprecision ranged from 1.6% (CV) for ion sodium to 5.5% (CV) for creatinine. Specimen related carry-over was not within the samples; specimen independent carry-over was found in some of the constituents studied. The relative inaccuracy is good for all the constituents assayed. Haemoglobin (290 mumol.l1) showed a positive interference with urate at three concentration levels (low, medium and high). Bilirubin (up to 300 mumol.l-1) caused a negative interference with creatinine at three concentration levels. Turbidity (trigliceride up to 4 mumol.l-1) stated a positive interference with creatinine at three concentration levels and with AST at two concentration levels (low and medium). Turbidity also caused a negative interference with urate at three concentration levels and with urea at two concentration levels (low and medium).

Automation↗
PubMedDate not supplied

Effects of long-term therapy with either heparin or low-molecular-weight heparin on serum lipid levels. A prospective study.

Beside the anticoagulant and antithrombotic activity, heparin also exerts a lipolytic activity. In a prospective study on patients with venous thromboembolism and some contraindications to coumarin therapy, a low-molecular-weight heparin (Fragmin) was compared to unfractioned (UF) heparin in terms of both efficacy and safety. A secondary aim was to study the influence of both types of heparin on serum lipid levels. Sixty-six consecutive patients who were not taking concomitant treatment with lipid-lowering drugs entered the study. Patients received treatment with either UF heparin, 10,000 IU s.c., b.d., or Fragmin 5,000 IU anti-factor Xa s.c., b.d. for a period of 3 or 6 months, according to whether the initial diagnosis was deep venous thrombosis or pulmonary embolism. Each patient was followed up at 6-weekly intervals, and blood samples were obtained at discharge, and then 6 and 12 weeks after discharge. Finally, a further sample was obtained 3 months after therapy was discontinued. Total cholesterol levels increased significantly in both groups of patients: levels increased from 193 +/- 56 to 246 +/- 63 mg/dl in the UF heparin group (p < 0.001), and from 189 +/- 53 to 222 +/- 47 mg/dl in the Fragmin group (p < 0.05). The increase was mostly due to a very strong increase in HDL cholesterol levels in patients receiving UF heparin (from 46 +/- 12 to 71 +/- 23 mg/dl; p < 0.000005). Three months after discharge, HDL cholesterol levels were significantly higher in patients taking UF heparin than in patients in Fragmin (p = 0.006). By contrast, patients on Fragmin exhibited a significant increase in LDL cholesterol levels: from 112 +/- 39 to 139 +/- 37 mg/dl; p < 0.01.

Adult↗