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Biomedical subjects

H Mathieu

Publications and source records attributed to H Mathieu.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Early synergistic killing activity at concentrations attainable in CSF of amoxicillin or cefotaxime and aminoglycosides against Haemophilus influenzae.

Rapid eradication of bacteria from the CSF is critical for the outcome of Haemophilus influenzae meningitis in children. In 15 patients studied, the mean H. influenzae colony counts in CSF were 10(5) CFU/ml (range: 10(2) to 10(9) CFU/ml). Time-kill curves were determined for amoxicillin and cefotaxime alone and in combination with gentamicin or amikacin, against 60 clinical isolates of H. influenzae at concentrations equivalent to those found in CSF following systemic administration. Against beta-lactamase-negative strains (n = 44) a bactericidal effect was observed at 18 h for amoxicillin alone, at 5 h for amoxicillin plus aminoglycosides and at 2.5 h for cefotaxime with or without aminoglycosides. Against beta-lactamase-positive strains a bactericidal effect was observed at 18 h for cefotaxime, at 5 h for amoxicillin plus aminoglycosides and at 2.5 h for cefotaxime plus aminoglycosides. It appears that despite low concentrations of gentamicin or amikacin in the CSF, the accelerated killing of H. influenzae provides a rationale for the initial use of the combination of cefotaxime and aminoglycosides in the initial treatment of H. influenzae meningitis.

Aminoglycosides↗
PubMedDate not supplied

Pharmacokinetics of cefotaxime and desacetylcefotaxime in the newborn.

A study of the pharmacokinetic parameters of cefotaxime (CTX) and desacetylcefotaxime (dCTX) in newborns was conducted; the former is commonly used for neonatal infections. The elimination half life of CTX correlated with gestational age (GA) and postnatal age (PNA). Elimination of dCTX was longer permitting a synergistic or additive effect with CTX against Gram-negative bacteria. CTX is indicated in the treatment of neonatal sepsis because of the increasing resistance of Escherichia coli to ampicillin and its good efficacy against group B streptococcus.

Cefotaxime↗
PubMedDate not supplied

Immunocytochemical localization of vitamin D-dependent calcium-binding protein in the yolk sac of the rat.

The yolk sac from normal pregnant rats contains a vitamin D-dependent calcium-binding protein (CaBP). To localize CaBP within the yolk sac, a rabbit antiserum specifically directed against purified rat CaBP, in indirect immunofluorescence and immunoperoxidase, has been used. Using yolk sac sections, positive reactions indicative of the presence of CaBP were found only in the endodermal cell layer. A method for isolation of pure endodermal cells, using EDTA treatment, was developed. On smears of isolated endodermal cells exposed to anti-CaBP antiserum, CaBP was distributed throughout the endodermal cytoplasm; no CaBP was detected in the nucleus. Our results suggest that the endodermal cells, which are functional absorptive cells of the yolk sac, may play a role in vitamin D-mediated processes.

Animals↗
PubMedDate not supplied

Comparative measurements between a new logging tool and a reference instrument.

Measurements were performed on reference samples (D2O-H2O mixtures) and on highly heterogeneous rocks (Vosges sandstone) with a new logging tool designed to give access to a high spatial resolution, below 1.5 cm on the vertical scale, for a toroidal sensitive volume of 20 cm3. The results were compared to measurements obtained on a clinical magnetic resonance imaging (MRI) equipment working at the same frequency (4.3 MHz). T2 differences as high as 30% were observed for the reference samples; the shortest values were obtained with the logging tool. Porosity profiles of the rock samples were also compared to reference profiles obtained with a conventional computed tomography (CT) scanner. Both nuclear magnetic resonance (NMR) measurements underevaluate porosity by 2-4% for short T2 values (< 10 ms).

Equipment Design↗
PubMedDate not supplied

[Development of a method for determining lead blood levels with chronopotentiometry].

A potentiometric stripping analysis method for blood lead determination, using Radiometer Tracelab PSU 22, has been investigated. Hemoglobin precipitation by hydrochloric and perchloric acids mixture allows to obtain the same signal for the same lead concentrations in aqueous standards and various blood samples. Thus it is possible to use a time saving calibration procedure. Equilibration time increase improved method sensitivity and precision. The analysis time was 3 minutes per sample. The detection limit was 0.006 microM/L. The relative standard deviation was 3.6% for 1.351 microM/L and 6% for 0.203 microM/L. The results of 66 determinations obtained by this method and by graphite furnace atomic absorption spectrometry were compared (R=0.991). Potentiometric stripping analysis is less expensive and very convenient for clinical laboratories.

Blood Chemical Analysis↗
PubMedDate not supplied

[Value of chlormethine in children with corticoid-dependent or partially corticoid-sensitive nephrosis, in steroid poisoning].

Mechlorethamine was administered at a low dose (0.8 mg/kg) to 27 children presenting with steroid dependent or partially responsive nephrotic syndrome, with signs of steroid toxicity. This drug induced a fast decrease of proteinuria (average delay: 7 days). It led to long lasting remission (average follow-up 34 months) in 16 cases (59%). Relapse occurred in 11 children (41%) most often (9 of 11 cases) in the first 7 months. However the evolutive pattern was clearly improved in 5 of these cases. Altogether, mechlorethamine allowed to stop corticosteroid therapy or, at least, to reduce the given dose, with a decrease of the signs of steroid toxicity, in 78% of the cases. In 6 cases (22%) evolution was almost not improved. One may hope that this dosage of mechlorethamine will not be gonadotoxic. This should be checked later on.

Adolescent↗
PubMedDate not supplied

[Chronic renal insufficiency in the child. Etiology, development and prognosis].

Our study concerned 147 children with chronic renal failure (CRF) (creatinine clearance less than 50 ml/min/1.73 m2). Its goal was to analyse the distribution of primary renal diseases, natural history of renal failure (RF) according to etiology, and long term survival. Renal diseases responsible for RF were: malformations of the urinary tract (38%), glomerular pathology (26%), hereditary renal diseases (20%), isolated renal hypoplasias (11%), and miscellaneous (5%). Corticoresistant nephrosis accounted for 34% of glomerular diseases and nephronophtisis 63% of hereditary renal diseases. On the whole, RF was related with an uropathy or renal hypoplasia in half of cases and with congenital renal disease in almost 3/4 of cases. The natural history varied according to primary renal disease: slow deterioration after a period of relative stability for uropathy or renal hypoplasias, slow and regular deterioration for nephronophtisis, rapid deterioration for glomerular diseases.

Adolescent↗
PubMedDate not supplied

Long-term outcome of children with malformative uropathies.

125 cases of severe malformative uropathies, 42 urethral valves (V), 52 degree III vesicoureteral refluxes (VUR), 18 ureterovesical junction stenoses (UVJ), 13 pyeloureteral junction stenoses (PUJ), were studied for a period of 12 years. Based on the hypothesis that prognosis depends on the number of residual nephrons, we used the glomerular filtration rate (GFR) as our basic reference. 62% of our cases had an initial GFR below 50 ml/min/1.73 m2 and 30% had GFR's below 25. Early diagnosis and intervention are important for improvement of GFR. Of the 32% who improved, most were diagnosed in the first year of life, and the exceptional few after 2 years. The extent of initial renal damage is also a limiting factor. Improvement was rarely seen when the initial GFR was below 30 ml/min/1.73 m2. There was a correlation between the initial and final GFR levels. Renal degradation (28% of cases) is most influenced by follow up time. The average age of end stage renal failure (ESRF) onset was 11 years 4 months, but is earlier for V than for VUR. Onset is even earlier when initial damage is more severe. As normal GFR does not exclude later degradation of renal function, another indicator of the risk of this type of evolution should be adopted.

Child↗
PubMedDate not supplied

Hormonal control of intestinal calcium-binding protein concentrations at weaning in rats.

In rats, the intestinal concentration of immunoreactive Ca-binding protein was shown to increase at weaning. We now report that injections of 1,25-dihydroxycholecalciferol (1,25(OH)2D3, 25 ng or 10 ng/day) in suckling rats on days 11, 12 and 13 induce a premature rise of the intestinal Ca-binding protein concentrations, associated with increased plasma Ca concentrations. No effect is seen after 25-hydroxycholecalciferol, or after hydrocortisone administration. L-Thyroxine, at high doses (50 micrograms/day) and at more physiological doses (2 micrograms/day) induces a significant rise of the intestinal Ca-binding protein concentrations and a decrease of plasma Ca concentrations. The association of 1,25(OH)2D3 (at 10 ng/day) and L-thyroxine (at 2 micrograms/day) does not cause an additive effect on Ca-binding protein concentrations and does not change plasma Ca. These results suggest that 1,25(OH)2D3 and thyroxine are probably involved in the regulatory mechanisms of the intestinal Ca-binding protein synthesis at weaning.

Animals↗