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Biomedical subjects

F Louis

Publications and source records attributed to F Louis.

At least 37 records · Page 2Linked to original sources
PubMed1987

Obstetric diagnosis and perinatal mortality.

A multidisciplinary team composed of obstetricians, pediatricians, and pathologists examined the causes of 453 consecutive perinatal deaths, which occurred between 1978 to 1982. A clear distinction between obstetric diagnosis and infant cause of death was made, and a prinicpal obstetric and infant diagnosis was assigned to each death. Perinatal death rates by obstetric category were calculated. The rates varied from 6.1 per 1000 births in uncomplicated cases to 217.4 per 1000 births in isolated intrauterine growth retardation. The causes of perinatal death within obstetric categories were tabulated. Nonviability or the complications of prematurity (65%) were the leading causes of death when there was third-trimester bleeding, premature labor, or premature rupture of membranes. Anoxia (59%) was the most frequent cause of death when there was hypertension/pre-eclampsia or other uteroplacental insufficiency states. Death from congenital abnormality accounted for 17.7% of all perinatal deaths. A focus on the causes of perinatal death with obstetric diagnostic categories helps weigh the risk of prematurity versus the risk of anoxia in the management of high-risk gravidas.

Boston↗
PubMed1987

Receptor-assay for endogenous inhibitors of Na-K ATPase.

It is now accepted that there is an endogenous digitalis-like substance (EDLS), previously called natriuretic factor, present in different mammalian species which participates to the regulation of the sodium balance and at least in some situations, to the genesis of hypertension. The physiological and pathophysiological role of this substance is well recognized. However, its chemical nature remains elusive. Our purpose was to define a receptor assay for this EDLS in order to be able to measure its concentration in urine and blood. To do so, we first prepared a pool of lyophylised urine from salt loaded men. The active material was isolated by Sephadex G25 chromatography. Using the same active fraction, we investigated its biological effects. Series of experiments have demonstrated the various properties of the EDLS: inducing natriuresis when injected into a rat, diminishing short circuit current in toad's bladder and colonic mucosa of rat in in vitro preparations, inhibiting Na-K ATPase activity in isolated toad's bladder cells, binding to ouabain receptors and cross-reacting with different antibodies directed against digoxin. Among these properties, the binding to ouabain receptors offers the unique opportunity to progress in our knowledges of the substance, making possible the calculation of its constant of affinity and the estimation of the molality of the active material contained in a gram of crude extract. Knowing the constant of affinity of the EDLS for its receptor would provide the best identification of the substance as long as we do not know its exact chemical nature.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Are opioid peptides co-localized with vasopressin or oxytocin in the neural lobe of the rat?

The content of vasopressin, oxytocin, neurophysin, leucine-enkephalin, methionine-enkephalin, dynorphin-(1-13), and alpha-neoendorphin in the rat neurohypophysis was measured after different periods of dehydration and after depolarisation of isolated neural lobes and of neurosecretory nerve endings. The rates at which the amount of neurohypophysial hormone and opioid peptides decreased, and the changes in the ratios between the amount of vasopressin or oxytocin and opioid peptide in the neurohypophysis after dehydration and in the incubation medium after depolarization in vitro cast some doubt on, and can be explained by mechanisms other than co-localisation of the different peptides.

Animals↗
PubMed1985

Fetal neuroblastoma and catecholamine-induced maternal hypertension.

A case of congenital neuroblastoma is presented. The interesting features are maternal symptomatology consistent with fetal production of catecholamines and the dilemmas of differential diagnosis. Observations are made on the frequency and diagnosis of fetal neoplasia. Antepartum detection of catecholamine metabolites may be the basis for the diagnosis of fetal neuroblastoma.

Adult↗
PubMed1985

The value of endocervical curettage as part of the standard colposcopic evaluation.

Whether to perform endocervical curettage (ECC) as part of a routine colposcopic examination in patients with an abnormal Papanicolaou smear remains controversial. Some studies consider ECC an essential part of a colposcopic examination regardless of the level of the squamocolumnar junction (SCJ); others consider it superfluous in cases where the SCJ can be visualized. Between January 1980 and December 1982, 278 new patients with abnormal Papanicolaou smears underwent colposcopy. Directed biopsies established the degree of cervical intraepithelial neoplasia (CIN) and ruled out invasive disease. ECC was done on every patient. A total of 51 patients (18%) had a positive ECC. Seven patients could not be evaluated because their records were incomplete. Of the 44 evaluable patients, 32 (73%) had satisfactory colposcopy. In the remaining 12 (27%) the upper limit of the transformation zone could not be seen clearly; in that group the degrees of CIN on colposcopic biopsy and ECC were in agreement in two cases; ECC revealed the degree to be less severe in four cases and more severe in six (50%). In the group with satisfactory examinations, 15 had the same degree of CIN on colposcopic biopsy and ECC; ten had less severe and seven (22%), more severe degrees of CIN on ECC. Of greatest clinical importance was that, overall, 11.5% had a positive ECC despite a satisfactory colposcopic examination. This study indicated that ECC provides unique and important information, justifying its inclusion as part of the standard evaluation of every patient undergoing colposcopy for abnormal cervical cytology.

Biopsy↗
PubMed1984

Simultaneous radioimmunoassay for plasma arginine-vasopressin and oxytocin using DEAE Sephadex A 25 extraction.

A sensitive and specific radioimmunoassay method for simultaneous measurement of plasma arginine vasopressin (AVP) and oxytocin (OT) has been developed utilizing an extraction technique on DEAE Sephadex A25. This procedure resulted in mean recoveries of 70.7% (AVP) and 65.4% (OT) in the peptide range of 5 to 100 pg/4 ml. The sensitivity of the assay is 0.5 pg/tube for AVP and 2 pg/tube for OT. The lower limit of detection for plasma extracts was 1.2 pg AVP/ml and 5 pg OT/ml plasma. Employing this method in normal human non smokers and ad libitum fluid the basal levels (mean +/- SE) of plasma AVP are 3.5 +/- 0.2 pg/ml in males and 4.6 +/- 0.4 pg/ml in females and the basal concentrations of plasma OT are 5.1 +/- 0.3 pg/ml in males and 5.4 +/- 0.3 pg/ml in females. Dehydration and water loading produced significant changes in plasma AVP and OT concentrations and a significant correlation exists between plasma AVP and plasma (r = 0.96, p less than 0.001) and urinary (r = 0.84, p less than 0.01) osmolality, but not between plasma OT concentrations and plasma (r = 0.11, NS) and urinary (r = 0.27, NS) osmolality. These results suggest that a wide range of physiological and pathophysiological changes in plasma AVP and OT can be simultaneously measured by the extraction procedure and the radioimmunoassay described.

Adult↗
PubMed1983

Phagocytosis and onset of human labor.

An in vitro experimental model has been developed which allows the study of amnion lysosomal enzyme release under controlled conditions. Briefly, a layer of human amnion membrane mounted on a specially designed reaction vessel serves as the reaction surface. We have noted that the addition of particulate material to these membranes incubating in pseudoamniotic fluid results in an increased release of the lysosomal marker enzyme N-acetylglucosaminidase when compared to the release in the absence of particles. This release is completely inhibited by iodoacetate and slightly by azide. A similar increased release is also noted with the use of term amniotic fluid as incubation medium when compared to centrifuged (30,000 g/20 min) amniotic fluid. Lecithin and lysolecithin were effective in releasing increasing amounts of enzyme. This increased release was noted only from membranes of placentas collected from subjects who had undergone cesarean section prior to labor. Membranes collected from vaginal deliveries after labor showed a baseline increased release but no further stimulation upon the addition of any of the substances. These results suggest that the release of lysosomal enzymes from amnion membranes is brought about by substance(s) present in amniotic fluid. Very probably, these are surfactants. The interaction of these substances with amnion cells would eventually result in an exponential burst of prostaglandin synthesis, which would result in labor.

Acetylglucosaminidase↗
PubMed1983

Changes in total serum immunoreactive neurophysins and corticosterone levels after restraint stress in rats.

This study indicates that total immunoreactive circulating neurophysins (IRN) increased in male rats submitted to acute restraint stress. Total immunoreactive serum corticosterone levels also were elevated, confirming the stressful character of the restraint situation. It is speculatively suggested that IRN elevations due to stress are the reflection of a corticotropin releasing factor (CRF)-IRN product.

Animals↗
PubMed1982

Suppressed prolactin but normal neurophysin levels in cigarette smoking breast-feeding women.

The hormonal responses to breast-feeding were studied during the first 3 post-partum weeks in ten women smoking more than fifteen cigarettes/day and in a control group. Basal PRL levels were significantly lower in smokers compared with non-smokers, but suckling induced acute increments in serum PRL and oxytocin-linked neurophysin, which were not influenced by smoking. The lactational pattern was normal, but smokers weaned their babies significantly earlier compared with non-smokers. Heavy cigarette smoking women have lower basal PRL levels and this may shorten the period of lactation.

Adult↗
PubMed1981

Urinary excretion of immunoreactive vasopressin in prepubertal children. Lack of correlation with urinary excretion of immunoreactive neurophysins.

The excretion of immunoreactive vasopressin (AVP) and neurophysins was determined in 24 h urine samples from 62 normal healthy children of various ages. Five groups of children were selected: group I (n = 7, aged 2 to 3 years), group II (n = 13, aged 3 to 5 years), group III (n = 16, aged 5 to 7 years), group IV (n = 16, aged 7 to 9 years), group V (n = 10, aged 9 to 11 years). The method used for urine AVP determination consisted of an extraction using a procedure slightly modified from that of Miller and Moses [14], coupled to a radioimmunoassay. The following urinary AVP excretions were obtained: group I mean: 70.8 ng/m2/24 h range: 51-150 ng, group II mean: 54.1 ng/m2/24 h range: 17-113.6 ng, group III mean: 55.2 ng/m2/24 h range: 18-106 ng, group IV mean: 39.9 ng/m2/24 h range: 11.7-77.9 ng, group V mean: 39.4 ng/m2/24 h range: 25.8-64 ng. The excretion of AVP was significantly correlated to the daily urinary osmolality (P less than 0.001) whether expressed in ng/24 h (r = 0.41) o rin ng/m2/24 h (r = 0.4.7). Neurophysins excretion ranging between 7 and 1,278 ng/24H is too variable to allow interpretation.

Age Factors↗
PubMed1981

[Modulation of the hypothalamo-neurohypophyseal system following environmental changes in rats].

The innate light-dark avoidance (step-through apparatus) was observed daily on 5 successive days in dehydrated and normal rats, the dehydration starting 24 hr before the first observation. We noted that latency scores from dehydrated groups and from the hydrated group tested together with a dehydrated group increased progressively. These significantly increased latencies did not appear when normally hydrated rats were tested alone. These changes in the temporal development of latencies seemed to be due to the fact that dehydrated rats were able to produce "fear odors" which increased the emotional reactivity of normal rats as well as theirs. The hypothalamo-neurohypophyseal function, characterized by the peripheral total neurophysins levels, also seemed to be modulated by these psychosocial and physical stresses. The neurophysins values from the hydrated group tested together with a dehydrated group were not statistically different from those of the latter group whereas they were higher than those of the hydrated group tested alone (Mann-Whithney; U = 28; n1 = n2 = 10; approach the significance). Further investigations are needed before establishing a definite relationship between the changes in latency scores on the one hand and the changes in neurophysins levels on the other hand. Nevertheless, one may well suppose that peripheral neurophysins levels play their own role in the adaptation of the organism to the environmental variations rather than only reflect the activity of the hypothalamo-neurohypophyseal axis.

Animals↗
PubMed1980

[The regulation of plasma aldosterone in hemodialysis patients].

The role of potassium in regulating plasma aldosterone has been studied in 7 patients with end-stage renal disease undergoing hemodialysis. Plasma renin activity (PRA), plasma aldosterone, cortisol, sodium and potassium, and total potassium loss were measured before and after two sessions of dialysis in each patient. The only difference between the two sessions was the potassium content of the dialysate (4 mmol/l versus l mmol/l). Plasma potassium, potassium pool and plasma aldosterone decreased significantly when the patients were dialyzed with a l mmol/l K bath. In contrast, the same parameters remained unchanged when the patients were dialyzed with a 4 mmol/l K bath. Irrespective of the dialysate used, there were no differences either in changes in body weight and PRA, or in plasma sodium and cortisol levels, before and after dialysis. In conclusion, in patients with end-stage renal disease, potassium predominates over PRA and volume depletion in the regulation of plasma aldosterone.

Adult↗