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Biomedical subjects

P Leblanc

Publications and source records attributed to P Leblanc.

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

[Low transverse laparotomy with rectus abdominus section in gynecology and obstetrics. Apropos of 1,000 cases].

The authors report 1,000 cases (357 cesarean sections, 230 hysterectomies for benign lesions, 157 conservative utero-adnexal procedures, 128 tubal plasties, 58 prolapse or incontinence procedures, 70 cancers) ,of laparotomies performed according to the technique described by Mouchel in 1980, i.e. strictly supra-pubic and transverse, from skin to peritoneum, including section of the rectus abdominis. This incision enables to perform in ideal technical conditions, with a minimal complication rate (3 hematomas, 2 incisional hernias for 1,000), and satisfactory esthetic results, almost all of the gynecological and obstetrical surgical procedures (90% of two among the authors' practice). The only contra-indications are, except for cases of previous median laparotomy, ovarian tumors. Neither the high risk of infection, nor obesity, extended hysterectomy, nor fetal distress, represent contra-indications, which is a definite advantage over the Pfannenstiel incision. As compared with the median incision which at some time offered similar results, the esthetics and mainly the strength of the abdominal wall are markedly superior.

Abdominal Muscles↗
PubMed1987

[Demonstration and topographical distribution of LHRH receptors in the central nervous system in the normal and castrated male rat].

The topographical distribution of [125I]-LHRH binding sites was studied on brain sections of adult male rat by quantitative autoradiography. High density of sites was observed in the hippocampus, amygdala and entorhinal cortex (4-7 fmol of LHRH bound/mg protein). Lower density of sites was observed in the septum and frontal cortex. The receptor density was not significantly modified at day 5 following castration. Under the same conditions the pituitary receptors were significantly increased. The presence of specific LHRH binding sites in the limbic system may explain the behavioural effect observed following intracerebroventricular injection of LHRH. However, their functions under physiological conditions remain to be elucidated.

Animals↗
PubMed1986

Relationships between radiographic change, pulmonary function, and bronchoalveolar lavage fluid lymphocytes in farmer's lung disease.

Ninety four dairy farmers were investigated by chest radiography, pulmonary function tests, and bronchoalveolar lavage. They were divided into five groups--1: 11 subjects with acute farmer's lung; 2: 25 subjects with previously diagnosed farmer's lung who had stayed on their farm; 3: 15 farmers with previously diagnosed farmer's lung who had left the farm; 4: 23 precipitin positive symptomless farmers; 5: 20 precipitin negative symptomless farmers. The study evaluated the relationships between radiographic changes measured with a scoring system derived from the International Labour Office (ILO) classification, the results of pulmonary function tests, and bronchoalveolar lavage fluid. Thirty eight subjects had radiographic evidence of interstitial pulmonary infiltrates. Group 1 had the highest percentage of lymphocytes recovered by bronchoalveolar lavage (mean 66.3 (SD 19.2]. For all subjects carbon monoxide transfer factor (TLCO) and total lung capacity were negatively correlated with radiographic changes (r = -0.45 and -0.30; p less than 0.001 and less than 0.01 respectively). TLCO was also negatively correlated with radiographic change in group 2 (r = -0.59, p less than 0.005). The percentage of lavage lymphocytes was correlated with radiographic changes for all subjects (r = 0.36, p less than 0.001), but this correlation was not seen within groups. This study shows good correlation between radiographic abnormalities, pulmonary function changes and the cellular composition of bronchoalveolar lavage fluid.

Adolescent↗
PubMed1986

Breathlessness and exercise in patients with cardiorespiratory disease.

Previous studies have led to the revival of the hypothesis that breathlessness is the perception of respiratory muscle effort and is present when the tension developed by muscles increases, when the muscles are weak, or when both conditions are present simultaneously. Using a category scale, the intensity of breathlessness was measured in 20 subjects (2 normal subjects and 18 patients) undergoing an incremental exercise test (50 to 100 kpm/min) to maximal capacity. The patients were selected to provide a heterogeneous group of pulmonary diseases, obesity, muscular weakness, and cardiac disease, with a wide variability in exercise capacity (250 to 1,900 kpm/min) and severity of dyspnea. Maximal inspiratory pressure (MIP), pleural pressure (Ppl), the extent of shortening of the inspiratory muscles as indicated by the tidal volume expressed as a percent of vital capacity (VT/VC), the rate of shortening as indicated by flow rate, the frequency of contraction as indicated by breathing frequency (fb), and the duty cycle (TI/Ttot) were measured throughout exercise to assess their relative contribution to the intensity of breathlessness. Using multifactorial analysis, the perception of breathlessness was significantly (p less than 0.01) related to the Ppl, inspiratory flow rate (VI), VT/VC, TI/Ttot, and fb. A multiple linear regression equation that included all these variables explained 69% of the variance, with no single factor being identified as uniquely predominant: Breathlessness = 3.0 (Ppl/MIP) + 1.2 (VI) + 4.5 (VT/VC) + 0.13 (fb) + 5.6 TI/Ttot) - 6.2 (R = 0.83). The intensity of effort required to produce a given pressure increases when the muscle is weak, when the velocity of contraction increases, or when the muscle shortens.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Estradiol activates methylating enzyme(s) involved in the conversion of phosphatidylethanolamine to phosphatidylcholine in rat pituitary membranes.

17 beta-Estradiol (E2) affects the sensitivity of pituitary cells to several neurohormones as LHRH, TRH, or dopamine, presumably by modulating receptor coupling mechanisms. We attempted to pinpoint the membrane processes underlying this modulation and studied the effect of E2 on pituitary membrane phospholipid methylation. Anterior pituitary membranes prepared from ovariectomized (ovx) or ovx plus E2-treated rats were assayed for phospholipid methylation. Methylated phospholipids were separated by TLC. Incorporation of [3H]methyl groups into phospholipids increased with membrane concentration and incubation time with S-adenosyl-L-methyl [3H]methionine; it was not Mg2+ dependent and was inhibited in a dose-dependent manner by S-adenosyl-L-homocysteine, methyltransferase inhibitor. pH was found to be critical. Formation of phosphatidyl-monoethanolamine, phosphatidyl-dimethylethanolamine, and phosphatidylcholine was markedly stimulated by treatment with E2. The effect increased progressively when animals were killed 15 h to 5 days after E2 implantation. The response involved a shift in the maximum velocity (Vmax) although there was no change in the available substrate for the methylating enzyme. This change in Vmax probably reflects changes in the amount of the methylating enzyme itself. Administration of 17 alpha-estradiol, an inactive stereoisomer of E2 was ineffective, pointing to a stereospecific interaction. After differential centrifugation of pituitary membranes, the highest specific methyltransferase activity was found in light mitochondrial (L) and microsomal (P) fractions and the lowest in nuclei (N) and the heavy mitochondrial (M) fractions. After sucrose density gradient centrifugation, methylated phospholipids were preferentially recovered from fractions corresponding to the endoplasmic reticulum and/or secretory granules. E2 treatment for 5 days did not modify the subcellular distribution of methyltransferase activity but stimulated it in all fractions; in contrast, it did not modify the activity of the other enzymes measured as fraction markers. Under the same experimental conditions, phospholipid methylation in membranes prepared from cortex, and anterior and mediobasal hypothalamic structures was not affected by the steroid, with the exception of a slight increment of [3H]methyl incorporation into mediobasal hypothalamic membrane phospholipids after 5 days of E2 treatment. These results indicate that E2-induced changes in pituitary responsiveness might be concomitant with selective effects of the steroid on specific membrane enzymatic activities involved in coupling mechanisms.

Animals↗
PubMed1986

[Compensation of the effects of shifts of anatomic positions of the heart on electrical tracings].

The heart can take different anatomical orientations in the chest of various subjects and even in the same subject. The corresponding changes in perspective can deeply affect the electrical tracings recorded by fixed standardized leads. One same electrogenesis takes many appearances, complicating the analysis. Anatomically intrinsic tracings can be obtained with O. H. Schmitt's Resolver from a usual X, Y, Z lead system. Its moving trihaedral X'', Y'', Z'', has to be brought onto the heart's axis and septum. Being directly related to the heart, these tracings become independent of the heart's anatomical position in the chest. They show the electrical to anatomical topographic relations. However, they have not been in favour because Clinicians could not relate them to their usual rules of interpretation. This Note describes how to obtain normalized tracings that can benefit from the usual criteria of interpretation, as if shifted hearts were seen in an intermediate position. A constant opposite intermediate shift is applied to the three, X'', Y'', Z'', intrinsic components to restore an arbitrary normalized position. The new X'', Y'', Z'', components follow the moving trihaedral brought on the individual anatomical position measured by X rays and echocardiography. A heart being naturally in an intermediate position gives tracings as if no Resolver was in action. Compensated (or normalized) ECG's or isopotential maps can be similarly computed.

Echocardiography↗
PubMed1986

Relationship among antigen contact, alveolitis, and clinical status in farmer's lung disease.

We studied 41 subjects with a history of farmer's lung disease who had been free of acute episodes for at least one year. Twenty-six were still in daily contact with hay (group 1), and 15 had ceased all antigenic exposure (group 2). While the incidence of dyspnea was similar in both groups, coughing and sputum were more frequent in group 1. Inspiratory crackles were frequent in group 1 subjects (15 of 26) and absent in all group 2 subjects. In both groups, a high percentage of lymphocytes was demonstrated by bronchoalveolar lavage: 52.5% +/- 21.1% (mean +/- SD) and 26.3% +/- 18.7%, respectively. Lymphocytic alveolitis (greater than 22% lymphocytes) was more common in group 1 (23 of 26) than in group 2 (6 of 15). There was no relationship between functional abnormalities and the intensity of the alveolitis. We conclude that lymphocytic alveolitis may persist after an acute episode of farmer's lung disease, but the intensity of the alveolitis is not associated with functional alterations.

Acute Disease↗
PubMed1985

The effect of ovine pineal compounds prepared under red or green light on the activity of male rat anterior pituitaries in vitro.

A high molecular weight fraction XM100R (MW A 100,000) was prepared by ultrafiltration from ovine pineals using two different extraction methods under red light conditions (lambda greater than 600 nm). This fraction stimulates the release of radioimmunologically active luteinizing hormone (LH) of anterior pituitaries in vitro. The ultrafiltration fraction PM30R (MW greater than 30,000 and less than 100,000) was found to be radioimmunologically active only when the "Bensinger" extraction procedure was applied. However, when comparable fractions were prepared under green light and incubated with half-pituitaries, all the incubation media of the ultrafiltrated fractions, XM100R, PM30R, PM10R (MW greater than 10,000 and less than 30,000) UM2R (MW greater than 1000 and less than 10,000), UM05R (MW greater than 500 and less than 1000) and UM05F (MW greater than 500), reacted with anti-LH. This may mean that under green light conditions the high molecular weight ovine pineal compounds in XM100R are disintegrated and/or split up into small molecules which can stimulate the release of LH, or crossreact with the anti-LH serum.

Animals↗
PubMed1985

[The harpoon technic in excision of subclinical mammary lesions. Preliminary results].

Preliminary results are reported of the use of a surgical technique since April 1983 for excision of subclinical mammography-observed anomalies. The procedure involves the insertion of a harpoon-shaped metallic thread, after detection by mammography, to obtain guidance of surgical procedures. Preliminary results in 36 cases included the detection of 10 cancers, confirming documented data in this field, and it would therefore appear worthwhile continuing along this pathway of early diagnosis.

Adult↗
PubMed1985

[Occult cancer of the breast].

21 cases of occult breast cancer were reviewed retrospectively. The patients were followed up from 1 to 9 years. Only one of these patients had partial axillary nodal disease and none had recurrence of mammary neoplastic disease. Thus, the prognosis of occult breast cancer is much better than that of clinical breast cancer and we think that all possible efforts must be made it order to detect breast cancer earlier. Mammography seems to be the best form of screening and in our opinion in every suspect disease surgical exploration must be performed.

Adult↗
PubMed1984

Subcellular distribution of particle-bound neutral peptidases capable of hydrolyzing gonadoliberin, thyroliberin, enkephalin and substance P.

Subcellular fractions from rat anterior pituitary homogenates were obtained by differential and gradient centrifugation, identified with the help of marker enzymes and screened for peptidases capable of hydrolyzing gonadoliberin, thyroliberin, enkephalin and substance P. Since each neuropeptide is susceptible to cleavage by more than one enzyme, specific substrates or inhibitors have been used for the selective determination of the individual peptidasic activities. Among the various enzymes tested, the angiotensin-converting enzyme, the thermolysin-like metalloendopeptidase ('enkephalinase'), a thyroliberin-degrading enzyme and some aminopeptidasic activities were found to be associated with the plasma membrane. Other aminopeptidases, a gonadoliberin-degrading and a substance-P-degrading enzyme are associated with the mitochondria and thus are most likely not involved in the biological inactivation of neuropeptides.

Animals↗
PubMed1984

Biosynthetic utilization of photoreactive fatty acids by rat liver microsomes.

The photoreactive omega-diazirinophenoxy derivatives of nonanoate, undecanoate, tridecanoate, and pentadecanoate were shown to be activated by rat liver microsomes to the corresponding acyl-CoA derivatives. The Km and Vmax for these fatty acid analogues were determined: the values obtained indicate that the addition of a photoreactive group to an alkyl chain has an effect similar to that of elongation of the chain by about seven carbons. Incubation of microsomes in the presence of lysophospholipids resulted in the incorporation of the photoreactive fatty acids into the corresponding phospholipids. The ability of mammalian systems to utilize these photoreactive fatty acids for phospholipid synthesis establishes their suitability as photoaffinity analogues of fatty acids.

Acyl Coenzyme A↗
PubMed1984

Characterization of a neutral endopeptidase localized in the mitochondrial matrix of rat anterior pituitary tissue with GnRH as a substrate.

We have determined the subcellular localization of an endopeptidase activity able to degrade gonadotropin releasing hormone (GnRH) and present in the rat adenohypophysis. After fractionation of tissue homogenates in 0.25 M sucrose by differential centrifugation, about 25% of the total cellular GnRH degrading activity was found to be sedimentable and recovered from heavy (M) and light (L) mitochondrial fractions with a distribution pattern similar to that of the mitochondrial and lysosomal reference enzymes cytochrome oxidase and beta-galactosidase. Upon further fractionation on sucrose density gradients, the activity comigrated with mitochondria. The peptidase appears endowed with a structure-linked latency; the activity is low in a freshly prepared mitochondrial fraction and increases upon treatment with membrane disrupting agents in a manner similar to that of malate dehydrogenase, a component of the mitochondrial matrix. Determination of GnRH cleavage sites was performed by amino acid analysis of the fragments obtained after incubation of the peptidase with (3H)-GnRH labelled on the pyroglutamic acid residue, in presence of carboxypeptidase and peptidyldipeptidase inhibitors. The fragments were separated by ion-exchange chromatography on an Aminex Q-15S column and purified by chromatography on silica gel plates. Fragments 1-2, 1-3, 1-4, 1-5 and 1-6 were all present as early as 1 min after the beginning of incubation. Formation of each of them was inhibited to the same extent by EDTA, mersalyl acid, dithioerythritol and Na deoxycholate. The same fragmentation pattern was observed after partial purification of the enzyme by gel filtration. These data indicate that cleavage of several peptide bonds may result from a possibly single endopeptidase located in the mitochondrial matrix space.

Animals↗