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Biomedical subjects

C Kindermans

Publications and source records attributed to C Kindermans.

35 records · Page 2Linked to original sources
PubMed1990

Glomerular function and microalbuminuria in children with insulin-dependent diabetes.

Renal function has been evaluated in 45 diabetic children (age 12.5 +/- 4 years) with a mean diabetes duration of 4.9 +/- 3.5 years. Glomerular filtration rate (GFR; inulin and creatinine clearances), renal plasma flow (RPF; PAH clearance), resting urinary albumin excretion (UAE) were measured and compared with indexes of metabolic control: Hb A1C and blood glucose values (mean, post-prandial and maximal excursion) on the same day. GFR (inulin clearance) and RPF were significantly increased in the diabetic group (171 +/- 31 and 778 +/- 172 ml/min per 1.73 m2) compared with controls (124 +/- 18 and 631 +/- 128 ml/min per 1.73 m2). Both parameters were strongly correlated (r = 0.73; P less than 0.001). Creatinine clearance was not correlated to inulin clearance. Hyperfiltration (inulin clearance above 160 ml/min per 1.73 m2) was noted in 61% of the patients and was independent of diabetes duration. Five diabetic children had a UAE level above 15 micrograms/min. No relationship could be established between UAE and any of the metabolic indexes; GFR was weakly correlated to HbA1C (r = 0.35; P less than 0.05), to mean (r = 0.37; P less than 0.05) and post-prandial blood glucose (r = 0.37; P less than 0.05). In contrast, there was a strong correlation between GFR and the maximal blood excursion (r = 0.62; P less than 0.001). The study shows that renal abnormalities can be detected with a high frequency in diabetic subjects characterized by both an early onset and a short duration of diabetes and suggests the need for a more systematic evaluation of renal parameters in this population.

Adolescent↗
PubMed1990

Renal functional reserve in children with reduced renal mass: study by two dietary periods.

It has been suggested that the "renal functional reserve" (RFR) defined by the rise in glomerular filtration rate (GFR) after a protein load could disappear in patients with severe nephron loss but with a normal GFR. This study compared, in 17 children, inulin clearance (Cin) measured by the plasma inulin plateau at the end of two 14-day randomized periods differing in protein intake: 100% (low protein, LP), or 200% (high protein, HP) of recommended dietary allowances (RDA). Diets were aimed at maintaining food habits and energy intake. Compliance was assessed by records of the last 3-4 days, an interview with the dietician and by urinary nitrogen measurements. Mean actual protein intake was 109% (56%-139%) RDA for the LP period and 220% (163%-319%) RDA for the HP period. Cin did not change in 14 children with GFR below (n = 7) or within (n = 7) the normal range. Cin was higher in the HP period than in the LP period (+32, 50, 63%) in 3 children who had a 50% (single kidneys) or a 25% (sclerosed glomeruli) nephron loss. Non-responding children had a GFR below 105 ml/min per 1.73 m2. Nephron loss (70% sclerosed glomeruli) was estimated in only 1 child with no RFR. The results suggest that GFR measurement after prolonged dietary stimulation could help in evaluating the severity of nephron loss in children with normal or borderline GFR. The prognostic value of this test has to be confirmed by long-term follow-up.

Adolescent↗
PubMed1990

[Kidney functional reserve. An experimental study].

The renal functional reserve (RFR), the increase in glomerular filtration rate (GFR) induced by a protein load, seems to be diminished or even lost in renal failure. Our experimental study was undertaken to determine whether the RFR is lost beyond a given level of nephron reduction, using different protein loads. In the first two studies, RFRs were evaluated during an oral protein load consisting in a high-protein diet (30% casein) compared to a low-protein diet (7% casein). Each diet was given to SD rats (200 g) either for three weeks immediately after nephrectomy (Nx) or for four days one month after Nx. Nx was subtotal and consisted in removal of 65 to 85% of the mass of the renal parenchyma. The GFR evaluated by inulin clearance measurements increased considerably after a prolonged (+188%) or short-lived (+35%) oral protein load if less than 70% of the renal mass had been removed. Beyond this threshold of nephron amputation, the high-protein diet had no effect on the GFR, despite an increase in the residual renal mass (+200% in moderate and severe Nxs). In a third study, the GFR was measured one month after Nx and the effects of an infusion of amino acids (vamine) or of a placebo were compared, each rat serving as his own control. Extent of Nx was 0%, 50%, 65-70%, and 80%. Regardless of the extent of nephron reduction, the GFR increased under vamine, but interindividual variations in each group were marked (+5 to +70%).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1989

Enalapril does not alter renal function in normotensive, normoalbuminuric, hyperfiltering type 1 (insulin-dependent) diabetic children.

Using a prospective randomised double-blind crossover design, the effect of the angiotensin converting enzyme inhibitor enalapril compared to a placebo was studied in 18 normotensive, normoalbuminuric Type 1 (insulin-dependent) diabetic children. Each patient had a high normal or clearly elevated glomerular filtration rate (145 ml.min-1.1.73 m2 or higher) in the 6 months prior to the study. Enalapril, 0.5 mg.kg-1.day-1, was given for 4 weeks followed by placebo for 4 weeks, or vice versa. At the end of each period, glomerular filtration rate, renal plasma flow, blood pressure, plasma renin activity, and converting enzyme activity were determined. Enalapril caused significant reduction (p = less than 0.001) in blood pressure and converting enzyme activity and a rise in plasma renin activity. A slight but not significant rise in glomerular filtration rate and renal plasma flow without change in filtration fraction was observed. These data suggest that the renin angiotensin system is not involved in the glomerular hyperfiltration of Type 1 diabetes, and can be interpreted as showing no evidence for the presence of intraglomerular hypertension in these patients.

Adolescent↗
PubMed1989

Persisting glomerular hyperfiltration in short-term diabetic children without microalbuminuria.

The renal function in a group of diabetic children (n=29;age;4-17 yr; IDDM duration: 1,5-13 yr) was studied with a 3 year interval. At the first evaluation glomerular filtration rate (GFR) as assessed by inulin clearance was significantly increased compared to control values (167 +/- 32 vs. 124 +/- 18 ml/min/1.73 m2; pl less than 0.01). Eighteen out of 29 children exhibited a glomerular hyperfiltration (GFR greater than 160). Three years later mean GFR was identical (169 +/- 25 ml/min/1.73 m2) and 16 children were hyperfiltrating. Among them, 11 have had a persisting glomerular hyperfiltration over the 3-year period. Renal plasma flow (RPF) was positively correlated to GFR (r=0.7; p less than 0.01) and remained elevated at both evaluations (794 +/- 163 and 812 +/- 157 ml/min/1.73 m2, p greater than 0.01 vs, control values). When the children were separated into 3 groups according to IDDM duration no significant differences were observed in the results for GFR and RPF, Mean urinary albumin excretion was comparable at the 3-year interval, and not significantly different from the control values (5.2 +/- 3.7 and 8.2 +/- 6.6 respectively vs. 8.65 +/- 4 microgram/min). None of the children demonstrated a persistent microalbuminuria. This study reveals a high proportion of diabetic children with a persisting glomerular hyperfiltration, without any other symptom of incipiens nephropathy, If elevated GFR plays an important role in the development of diabetic nephropathy, this study emphasizes the value of regular evaluation of renal function in diabetic children.

Adolescent↗
PubMed1989

Anomalies in pH 7.40 correction in ionised calcium analysers.

As a preliminary step in a study of the effects of calcium ligands on the pH standardisation of ionised calcium (Ca2+) measurement in blood, the change in Ca2+ induced by Pco2 variation was investigated in 12 serum pools on three different instruments. This type of study should yield a log Ca2+ = f(pH) linear relationship in a pH range around pH 7.40 with a slope characterising the pH-sensitive calcium buffer capacity of the specimen. The pH 7.40 correction line should be horizontal. This was the case for an ICA2 analyser but not for an ICA1 or a Nova 8 analyser. The difference was due to an incorrect setting of the built-in slope correction factor in the ICA2: fortuitously its value was close to the effective slopes of the serum pools used for the test. Thus the anomalous behaviour of the ICA1 and the Nova 8 was due to a discrepancy between the standard built-in algorithm and the characteristics of our serum pools. These findings led us to question the use of a constant correction factor to normalise actual ionised calcium values.

Autoanalysis↗
PubMed1989

Inadequate algorithm: a cause for 'incorrect pH 7.40 correction' in ionized calcium analysers.

As a preliminary step in a study of the effects of calcium ligands on the pH standardization of ionized calcium (Ca2+) measurements in blood, the slope of logCa2+ = f(pH) linear relationship characterizing the pH-sensitive calcium buffer capacity of the specimen was investigated in 12 serum pools on three different instruments. The pH 7.40 correction line should be horizontal. This was the case for the ICA-2 but not for the ICA-1 and the NOVA-8. The discrepancy was caused by an incorrect setting of the built-in slope correction factor in the ICA-2; coincidentally, its value was close to the effective slopes of the serum pools used in the study. Thus, the 'abnormal' behaviour of the ICA-1 and the NOVA-8 was caused by an inadequacy of the built-in algorithm to the characteristics of our serum pools. These findings lead us to reconsider the use of a fixed and constant correction factor to normalize actual ionized calcium values.

Algorithms↗
PubMed1989

Anticoagulant-induced preanalytical errors in ionized calcium determination on blood.

When anticoagulated blood is necessary for ionized calcium (Ca2+) measurements especially in urgent circumstances, the type (sodium or 'calcium-titrated' heparinate) as well as the form (aqueous or dry) of anticoagulant induce preanalytical errors. To quantify these modifications Ca2+ was measured in three aqueous solutions and in three serum pools in different 'sampling' conditions. Incomplete syringe filling and specimen volume/syringe nominal volume ratio effects were tested. Syringes were rinsed (i) with saline to yield 'pure' dilution effect ('solution-dilution'); (ii) with sodium heparinate to study binding; (iii) with calcium-titrated heparinate to evaluate 'calcium-distortion'. All types of errors increased when syringes were not filled to their nominal volume, especially on small-sized specimens. Detailed tables provide percentage error values for all sampling conditions. Thus, 'solution-dilution' can reach -5%; binding is always important (-15 to -50%). 'Calcium-distortion' is minimal, around 1.25 mmol/l Ca2+, but can reach -7% for high Ca2+ and +10% for low Ca2+.

Anticoagulants↗
PubMed1987

Hypocalcaemic effect of WR-2721, S-2 (3-aminopropylamino) ethyl-phosphorothioic acid in an anuric haemodialysis patient.

The radio- and chemoprotective agent, S-2 (3-aminopropylamino) ethyl-phosphorothioic acid (WR-2721) has been reported to lower hypercalcaemia in patients with cancer, probably by increased renal calcium excretion and decreased parathyroid hormone (PTH) secretion and bone calcium resorption. The present study reports the first clinical use of WR-2721 in an anuric haemodialysis patient with severe secondary hyperparathyroidism. The drug was administered intravenously at different doses, i.e. 150, 300, and 500 mg/m2. The infusion was followed by a striking decrease of plasma immunoreactive (i) PTH within 30 min. The nadir of the iPTH decrease was reached at 60 min and was followed by a steady return to previous values. Serum ionised calcium decreased more progressively from 1.55 mmol/l initially to 1.30 mmol/l at 4 h after the 300-mg dose, remained at that level at 24 h, but rose again to pre-infusion values after 48 h. The extent and duration of the decrease in plasma iPTH and ionised calcium were dose-dependent. The circulating iPTH at 24 h was inversely related to the corresponding plasma ionised calcium concentration and had risen above preinfusion values at that time. Plasma concentrations of three other hormones, i.e. renin, insulin, and prolactin, were not affected by the administration of WR-2721. In conclusion, WR-2721 can induce a decrease in serum ionised calcium in the absence of any excretory kidney function. The rapid effect of the drug on circulating iPTH supports the notion of an interference with PTH secretion or catabolism.

Amifostine↗
PubMed1979

[Alcoholic ketoacidosis. One case (author's transl)].

Severe ketoacidosis sometimes develops in chronic alcoholics after increased alcohol intake associated with dietary restriction. This particular case was unusual from two standpoints: a considerable, prolonged and unexplained increase in serum free fatty acid, and discordance between the degree of ketonaemia and an abundant liver glycogen load.

Acidosis↗
PubMedDate not supplied

[Biochemical markers of bone remodeling: pre-analytical variations and guidelines for their use. SFBC (Société Française de Biologie Clinique) Work Group. Biochemical markers of bone remodeling].

Biochemical markers of bone turnover have been developed over the past 20 years that are more specific for bone tissue than conventional ones such as total alkaline phosphatase and urinary hydroxyproline. They have been widely used in clinical research and in clinical trials of new therapies as secondary end points of treatment efficacy. Most of the interest has been devoted to their use in postmenopausal osteoporosis, a condition characterized by subtle modifications of bone metabolism that cannot be detected readily by conventional markers of bone turnover. Although several recent studies have suggested that biochemical markers may be used for the management of the individual patient in routine clinical practice, this has not been clearly defined and is a matter of debate. Because of the crucial importance to clarify this issue, the Société Francaise de Biologie Clinique prompted an expert committee to summarize the available data and to make recommendations. The following paper includes a review on the biochemical and analytical aspects of the markers of bone formation and resorption and on the sources of variability such as sex, age, menstrual cycle, pregnancy and lactation, physical activity, seasonal variation and effects of diseases and treatments. We will also describe the effects of pre-analytical factors on the measurements of the different markers. Finally based on that review, we will make practical recommendations for the use of these markers in order to minimize the variability of the measurements and improve the clinical interpretation of the data.

Adolescent↗
PubMedDate not supplied

[Prescription of bone remodeling markers in hospitals].

Biochemical markers of bone turnover have for several years been considered as valuable parameters in research clinical studies, but their use in individual patients is still debated. Recently several position papers have proposed guidelines for their use in clinical practice in patients with post menopausal osteoporosis. In the present article, we report the results of a survey which aims at comparing the actual modalities of prescription of French physicians with the above-mentioned recommendations. We contacted by phone clinical chemists from 158 different hospitals and asked them to transmit to the concerned physicians of their hospital a detailed questionnaire for assessing which bone marker(s) is (are) prescribed and for which purpose (s), and if not prescribed, the reason of non prescription. We were able to analyze 309 questionnaires from 89 hospitals including 5 specialties, rheumatology (35.9%), endocrinology (18.1%), gynecology (11.0%), internal medicine (22.0%) and geriatry (12.9%). The results showed large discrepancies between the mode of prescription of a subset of physicians and the guidelines. The most often evoked reason for non prescription was a lack of information about bone markers suggesting a need for teaching courses. This survey has also shown that many physicians do not know exactly which parameters are effectively measured in their hospital and which are addressed to specialized laboratories underlining the importance of the dialogue between clinicians and clinical chemists. We propose that in a given hospital, the present article may serve as a basis for a discussion between clinicians and biologists about the development and/or the optimization of the measurements of these markers of bone turnover.

Biomarkers↗
PubMedDate not supplied

[Calciotropic hormones in rheumatology].

Calcium homeostasis maintenance is controlled by calciotropic hormones action. Bone is a major target tissue for PTH and calcitriol. Excess in at least one of two hormones may be deleterious to bone, leading to osteoporosis. Calciotropic hormones must of course be measured if an anomaly of serum calcium/phosphate is discovered. However, when the degree of osteopenia is discordant with the risk factors of osteoporosis in a given patient, it may be of value to measure calciotropic hormones, even if serum calcium/phosphate are normal. Previously undiscovered cause(s) for secondary osteoporosis may be diagnosed which, if untreated, may impair the efficacy of antiresorptive treatments (estrogens, biphosphonates, ...). Whether to measure calciotropic hormones or not in other less-defined groups of osteoporotic patients remains both debatable and debated.

Calcitonin↗