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Biomedical subjects

M Andre

Publications and source records attributed to M Andre.

At least 73 records · Page 4Linked to original sources
PubMed1987

[Complications of inguinal hernia in children].

From 1978 to 1985, 679 boys were operated for an inguinal hernia. 3 groups of patients must be considered. The bilateral inguinal hernias group (119 children) 73 patients were operated on both sides. 46 presented signs of hernia on the opposite side after the first operation and were operated again. In this group, there is a more important frequency of premature. But the classical notion that bilateral hernia are more common when the presenting hernia is on the left side, is not noticed. As a matter of fact, among the 46, there were 33 children operated at first on the right side. If a systematic bilateral exploration had been realised, it would here been useless in 82 per cent of the cases. The incarcerated inguinal hernia group 177 (26%) children were hospitalised for an incarcerated inguinal hernia diagnosis. 23 infants required emergency operation. Mostly, it was the first episode of a right hernia in a child under 3 months of age. 8 times a testicular infarction was noticed. The incidence of testicular lesion following incarceration of inguinal hernia is more important that the testicular atrophy after primary hernioplasty. This justify the surgical treatment for children of any age. The premature group 126 children were premature infants. In this group, a more important frequency of bilateral and incarcerated hernias are noted. 24 among these patients presented recurrent apnea episodes. To 8 of those children, the intervention was probably a benefit for the evolution of their apneas.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

A comparative study of the clinical results obtained with plastipore and ceramic ossicular prostheses in otologic surgery.

We describe our experience with clinical tolerance to total and partial ossicular prostheses using ceramic and plastipore and the functional results obtained. We have found that ceramic is well tolerated (with a 4% incidence of rejection) in contrast to plastipore (which had a 19% incidence of rejection). The ceramic partial and total prostheses give satisfactory function results, and 63% and 62% of our patients, respectively, were found to have postoperative air-bone gaps of less than 20 dB, and average air-bone gap gains of 16 and 21 dB.

Biocompatible Materials↗
PubMed1986

Preferential Photosynthetic Uptake of Exogenous HCO(3) in the Marine Macroalga Chondrus crispus.

The rate of HCO(3) (-) uptake by the red macroalga Chondrus crispus has been investigated. Unbalanced concentrations of free CO(2) and HCO(3) (-), generated by the photosynthetic activity, were detected in steady state conditions by using an exchange column apparatus linked to an assimilation chamber. Observing the variations of this gradient as influenced by the time of seawater transit from the assimilation chamber towards the column allowed an experimental determination of: (a) the actual gradient created by the photosynthetic activity, (b) the rate constant of the chemical conversion of free CO(2) to HCO(3) (-). With a value of 0.115 per second at pH 8.92, this rate constant was in good agreement with a previous estimation. By using a simple model, we show that the photosynthetic rate of HCO(3) (-) consumption can be estimated by the product of the actual gradient and the rate constant. In the conditions of the experiments reported here, this rate represented more than 90% of the whole photosynthetic flux.

Journal Article↗
PubMed1986

Perspective: three-dimensional imaging of the musculoskeletal system.

An evaluation of musculoskeletal disorders in 202 patients using three-dimensional CT displays has revealed the usefulness of the technique, especially in patients with fractures of skeletal areas with complex anatomy, articular disorders of the hip, and spinal stenosis. In some cases, plastic models of diseased areas have been created from the CT data and are reasonably accurate, providing a graphic representation of the disease and the ability to perform rehearsal surgery. A preliminary investigation of three-dimensional displays of MR images indicates that the technique is feasible, although its clinical practicality requires further analysis.

Fractures, Bone↗
PubMed1985

Oxygen Uptake and Photosynthesis of the Red Macroalga, Chondrus crispus, in Seawater: Effects of Oxygen Concentration.

With an experimental system developed for aquatic plants using the mass spectrometry technique and infrared gas analysis of CO(2), we studied the responses to various O(2) concentrations of gas exchanges with the red macroalga Chondrus crispus S. The results were as follows. (a) Irrespective of the CO(2) concentration, net photosynthesis was O(2) sensitive with a 45 to 70% stimulation at 2% O(2). Even with high CO(2), a significant Warburg effect was detected. (b) Although photosynthesis was CO(2) sensitive, O(2) photoconsumption was only weakly affected by CO(2) even at high CO(2) where it was still photodependent. (c) O(2) photoconsumption was always sensitive to O(2) concentration whatever the CO(2) concentration, but with O(2) exceeding 20% the kinetics disagreed with the Michaelis-Menten model, with saturation being reached more rapidly. With various CO(2) concentrations, the apparent K(m) (O(2)) ranged from 4 to 16% O(2) with a relatively constant V(max) (O(2)) of about one-third the V(max) (CO(2)). (d) Dark respiration seemed to be O(2) insensitive. These results are discussed in relation to the nature of the processes able to consume O(2) in the light, and seem to be consistent with a significant involvement of a Mehlertype reaction.

Journal Article↗
PubMed1985

Continuous Measurements of the Free Dissolved CO(2) Concentration during Photosynthesis of Marine Plants: Evidence for HCO(3) Use in Chondrus crispus.

An experimental system consisting of a gas exchange column linked to an assimilation chamber has been developed to record continuously the free dissolved CO(2) concentration in seawater containing marine plants. From experiments performed on the red macroalga Chondrus crispus (Rhodophyta, Gigartinales), this measurement is in agreement with the free CO(2) concentration calculated from the resistance to CO(2) exchanges in a biphasic system (gas and liquid) as earlier reported. The response time of this apparatus is short enough to detect, in conditions of constant pH, a photosynthesis-caused gradient between free CO(2) and HCO(3) (-) pools which half-equilibrates in 25 seconds. Abolished by carbonic anhydrase, the magnitude of this gradient increases with decreasing time of seawater transit from the chamber to the column apparatus. But its maximum magnitude (0.35 micromolar CO(2)) is negligible compared to the difference between air and free CO(2) (11.4 micromolar CO(2)). This illustrates the extent of the physical limiting-step occurring at the air-water interface when inorganic carbon consumption in seawater is balanced by dissolving gaseous CO(2). The direction of this small free CO(2)/HCO(3) (-) gradient indicates that HCO(3) (-) is consumed during photosynthesis.

Journal Article↗
PubMed1985

Estimation of virus density in sewage effluents by two counting techniques: comparison of precisions as a function of inoculum volume.

Two titration methods for the quantification of viruses present in the environment are compared--plaque counting and determination of the most probable number with a large number of inocula at each dilution. Titration of virus suspensions and of sewage samples showed that, for a given volume of inoculum, in most cases there was no statistically significant difference between the virus titres given by the two methods. The precision of the results was the same for the two methods. When the volume of inoculum used at each dilution differed from one method to another, the width of the confidence interval increased as the volume of inoculum decreased.

Bacteriological Techniques↗
PubMed1985

Influence of Mn(II) on NMR relaxation times of biological fluids.

The extent that various concentrations of the paramagnetic metal ion manganese [Mn(II)] affect nuclear magnetic resonance (NMR) relaxation times was studied in vitro. Serial dilutions of Mn(II) were prepared in distilled water, 4% human serum albumin, dog plasma, dog gallbladder bile, and dog hepatic bile. T1 and T2 of each were measured at 10.7 M Hz using magnetization recovery and spin-echo radiofrequency sequences, respectively. The results show that relaxation rates (1/T1 and 1/T2) increase in a linear manner with increasing concentration of Mn(II) in all of the solutions tested. Mn(II) dissolved in dog gallbladder and hepatic bile, dog plasma, and 4% human serum albumin reduced relaxation times to a greater extent than Mn(II) in water. T1 times were reduced to a greater extent than T2 values. Thus, in T1 weighted magnetic resonance images, the NMR signal used to produce images would be more sensitive to the presence of Mn(II) in these biological fluids than in water. Furthermore, the magnitude of this in vivo effect of Mn(II) on NMR relaxation parameters depends not only on the concentration of this paramagnetic ion, but also on the constituents comprising the biological fluids (intra- and extracellular water, bile, plasma) and the nature of the chemical molecular interactions between these constituents and Mn(II).

Animals↗
PubMed1984

Oxygen Uptake and Photosynthesis of the Red Macroalga, Chondrus crispus, in Seawater: Effects of Light and CO(2) Concentration.

With an experimental system using mass spectrometry techniques and infra-red gas analysis of CO(2) developed for aquatic plants, we studied the responses to various light intensities and CO(2) concentrations of photosynthesis and O(2) uptake of the red macroalga Chondrus crispus S. The CO(2) exchange resistance at air-water interface which could limit the photosynthesis was experimentally measured. It allowed the calculation of the free dissolved CO(2) concentration. The response to light showed a small O(2) uptake (37% of net photosynthesis in standard conditions) compared to C(3) plants; it was always higher than dark respiration and probably included a photoindependent part. The response to CO(2) showed: (a) an O(2) uptake relatively insensitive to CO(2) concentration and not completely inhibited with high CO(2), (b) a general inhibition of gas exchanges below 130 microliters CO(2) per liter (gas phase), (c) an absence of an inverse relationship between O(2) and CO(2) uptakes, and (d) a low apparent K(m) of photosynthesis for free CO(2) (1 micromolar). These results suggest that O(2) uptake in the light is the sum of different oxidation processes such as the glycolate pathway, the Mehler reaction, and mitochondrial respiration. The high affinity for CO(2) is discussed in relation to the use of HCO(3) (-) and/or the internal CO(2) accumulation.

Journal Article↗
PubMed1984

Digital arthrography of the wrist: a radiographic-pathologic investigation.

An analysis of digital arthrography of the wrist was accomplished in 10 cadaveric specimens. In each case, images were obtained during a 30-sec period in which a small amount of contrast material was introduced into the radiocarpal compartment; films were reviewed with and without subtraction technique. Pathologic examination of the sectioned specimens documented the accuracy of this arthrographic method. The sequence of contrast opacification of the various compartments of the wrist and the location and size of the defects within ligamentous and cartilaginous structures were ideally seen with digital arthrography. A previously unemphasized pattern of communication, that between the midcarpal and pisiform-triquetral compartments, was seen in two instances. Digital wrist arthrography seems to represent an excellent method to evaluate the patient with suspected soft-tissue injury.

Fluoroscopy↗
PubMed1984

[Value of prostaglandin E1 in cardiac malformations in the newborn infant].

Prostaglandin E1 (PGE1) was administered to increase ductus patency in 26 neonates who present a cyanotic heart disease with right ventricular obstruction (1st group, 13 cases) or congestive heart failure with left ventricular outflow obstruction (2nd group, 13 cases). Clinical improvement occurred in all but the oldest infant in the first group. The efficacy of PGE1 is inconstant in the second group, but medical status was very poor before treatment. We could usually reduce the dose of PGE1 but in no case we could stop the drug before surgery. Surgery could be delayed several hours or days to get an hemodynamic and biologic satisfactory condition and even a few weeks until the infants and their pulmonary arteries had grown (1st group). Side effects are common but relatively minor.

Ductus Arteriosus↗
PubMed1983

Effects of bromocriptine on pituitary-testicular function in the rat: possible inhibition of in vitro production of androgen by Leydig cells.

The effect of bromocriptine (BR) on pituitary-testicular function has been investigated in vivo and in vitro in adult male rats. Testosterone production in vitro by collagenase- dispersed Leydig cells from 84-day-old rats was evaluated in the presence and absence of hCG and/or different doses of BR. In the presence of 1.5 X 10(-5) M BR, both basal and hCG-stimulated testosterone production were decreased whereas at lower doses BR was ineffective. In vivo 60-day-old rats were injected sc with BR (150 micrograms/rat or 750 micrograms/rat twice daily) or vehicle for 24 days. This treatment reduced the plasma level and pituitary content of prolactin, slightly increased the plasma levels of LH and FSH but did not affect pituitary gonadotrophin content. Irrespective of the dose of BR injected, plasma levels of androgen did not change, but with the large dose of BR a decrease in testicular content of testosterone (P = 0.05) was observed. In the same animals the number of LH/hCG receptors was significantly reduced, and the sensitivity of the isolated Leydig cells to hCG stimulation in vitro was reduced; however, both the basal secretion and the maximum testosterone response to hCG were unaffected. These results show impairment of pituitary-testicular function in BR-treated rats, either as a result of BR-induced hypoprolactinaemia or as a consequence of direct effects of BR on the Leydig cells.

Androgens↗
PubMed1980

[Developmental changes in plasma gonadotropins and testosterone and in testicular lutropin receptors in normal and cryptorchid rats].

Testis weight, ventral prostate weight, plasma gonadotropins and testosterone and testicular LH receptors were assessed throughout sexual maturation in the 23 to 84 day old rat. Intact, sham-operated and cryptorchid rats (operated at day 21) were studied. In the intact rats, plasma FSH rose to a peak at day 33, and fell to a plateau from day 50 throughout adult life. Plasma LH showed a sharp peak at day 42. Testis LH receptor content increased continually with age, reaching a plateau at day 49, but there was no change in the affinity constant (Ka = 2.4 +/- 0.5 X 10(10) M-1) measured at four time intervals. These observations suggested that the peak of FSH initiated an increase in testicular LH receptors, and that the LH peak enhanced it. In the cryptorchid rats, FSH showed a maximum between days 30 and 40. After day 33, FSH was higher in the cryptorchid rats than in the controls. The pattern of plasma LH was different in controls and cryptorchids; in the latter group, LH was often higher than in the controls. Testicular LH receptors increased continually between days 23 and 84, but Ka remained constant (Ka = 2.2 +/- 0.9 X 10(10) M-1) during that period. When compared with the control rats, the cryptorchid animals showed an increased concentration of testicular LH receptors at day 84, but this concentration decreased at days 35, 49 and 84; plasma testosterone also declined at days 23 and 49. These data suggested that the Leydig cell function of the cryptorchid rats was altered.

Animals↗