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Biomedical subjects

R Leclercq

Publications and source records attributed to R Leclercq.

At least 127 records · Page 7Linked to original sources
PubMed1984

[Antibacterial activity of lamoxactam in combination with penicillin, ampicillin and amoxicillin against clinical strains of Enterococci, group B Streptococci and Listeria].

The antibacterial activity of moxalactam-penicillin combinations was studied against clinical isolates of Enterococci (20 strains), group B Streptococci (10), Listeria (3) and Enterobacteriaceae (10), using a microtiter checkerboard (FIC index, FBC index). Combinations of moxalactam (MX) with penicillin G, ampicillin or amoxicillin were usually synergistic against Enterococci and Listeria but with high MX concentrations. Against group B Streptococci, penicillin-MX combinations were synergistic (40%) or additive (60%) with MX concentrations easily achievable in the CSF.

Amoxicillin↗
PubMed1983

[Acute Actinobacillus actinomycetem comitans aortic endocarditis].

A 55 year old man presented an acute massive primary aortic endocarditis, with blood cultures showing the presence of Actinobacillus actinomycetem comitans. The rapidly worsening character of this endocarditis, which required an emergency valve replacement, was the hallmark of this case. The clinical and haemodynamic signs of the often missed massive acute aortic incompetence are recalled.

Actinobacillus Infections↗
PubMed1981

Seasonal, circadian and episodic variations of human immunoreactive beta-MSH, ACTH and cortisol.

The 24-hour profile of plasma levels of immunoreactive beta-MSH (IR-beta MSH), ACTH and cortisol was obtained at 15-min intervals in six normal males in summer and winter. In the radioimmunoassay used, dilution curves of human beta-MSH and human beta-LPH were not parallel. A seasonal variation in basal pituitary-adrenal secretion, with higher levels in winter than in summer, was demonstrated. A circadian rhythm was found to be significant for ACTH, IR-beta MSH and cortisol in all investigations. Whereas ACTH and cortisol patterns were largely concordant in all studies, there was a significant desynchronization of the circadian rhythm of IR-beta MSH as compared to ACTH in five cases. Eighty-three percent of the secretory spikes of cortisol but only 68% of the IR-beta MSH spikes were concomitant with an ACTH spike. Correlations between maximal levels of concomitant spikes were higher during the quiescent period of pituitary-adrenal secretion (22.00--04.00) for ACTH-cortisol whereas for ACTH-IR-beta MSH, highest correlations were found during the active early morning secretory phase (04.00--10.00). For the three plasma constituents studied, longer apparent half-lives were found to occur when the basal level before spiking was already elevated, suggesting that ACTH, beta-LPH and cortisol are secreted in bursts superimposed on a continuous basal secretion. Absolute increments of concentration appeared to be relatively independent of the level before spiking. It is suggested that the dissociations between ACTH and IR-beta MSH fluctuations in plasma observed here result from in vitro proteolysis of beta-LPH.

Adrenocorticotropic Hormone↗
PubMed1981

Calcium deprivation enhances glucagon release in the presence of 2-ketoisocaproate.

The effect of calcium deprivation upon glucagon and insulin release was studied in the rat pancreas perfused in the presence of 2-ketoisocaproate (10 mM). Control perfusions were conducted in the presence of glucose (11.1 mM). In the presence of 2-ketoisocaproate, the decrease in the extracellular concentration of calcium provoked a dramatic, but reversible, enhancement of glucagon release. Such a secretory response was similar in pattern to that seen upon calcium omission in the presence of glucose. Bio-Gel P-30 chromatographic studies showed that only true glucagon (mol wt, 3500) was liberated in the pancreatic effluent during the period of calcium deprivation. On the other hand, the secretion of insulin induced by 2-ketoisocaproate was, like that elicited by glucose, markedly inhibited upon the decrease in extracellular calcium concentration (80% and 65% inhibition, respectively). The results are interpreted in support of the hypothesis that calcium may play an inhibitory role in the control of glucagon release. It is suggested that such a role is somehow linked to the metabolism of exogenous nutrients in the A2 cells.

Animals↗
PubMed1981

[Roentgenological evolution of bone maturation. A case of congenital myxoedema treated at forty years old (author's transl)].

Non treated congenital myxoedemateous adults are rarely met. If such patients are pubescent, bone maturation is completed. Thyroïd hormone is not the only factor of bone maturation. Non treated congenital myxoedemas cannot be pubescent if bone maturation process had not started. Probably, such an association is not published. The authors report one case of this paradoxical association developed to the hole bone maturation.

Adult↗
PubMed1979

Interactions of alpha-ketoisocaproate, glucose and arginine in the secretion of glucagon and insulin from the perfused rat pancreas.

The effects of alpha-ketoisocaproate (KIC, 10 mmol/l) on glucagon and insulin release were studied in the in vitro perfused rat pancreas. The experiments were performed at low glucose concentration (3.3 mmol/l) in the absence or presence of arginine (10 mmol/l). In all the experiments KIC induced a marked and not rapidly reversible inhibition of glucagon release. This inhibition was more pronounced in the absence (76 percent) than presence of arginine (61 percent). These inhibitory patterns closely duplicated those which were seen in parallel experiments which included a rise in the concentration of glucose (from 3.3 to 11.1 mmol/l). KIC was also a potent stimulator of insulin release. The results are compatible with the view that the intracellular metabolism of KIC and glucose plays an essential role in the regulation of glucagon release by exogenous substrates.

Animals↗
PubMed1978

Simultaneous study of cortisol, growth hormone and prolactin nyctohemeral variations in normal and obese subjects. Influence of prolonged fasting in obesity.

Hourly integrated concentrations (IC) of growth hormone (GH), prolactin (PRL) and cortisol were determined by a continuous sampling procedure in six obese women, before and at the end of a 12 day fast, and in eight normal controls under basal conditions. Hormonal 24 h IC and nyctohemeral variations were calculated from these data. Nyctohemeral rhythms were investigated by the periodogram method. A significant increase over basal values of 24 h IC of PRL, GH and cortisol was observed at the end of the fasting period. Nyctohemeral variations--but not nyctohemeral rhythm--of IC-GH were found in normal subjects. They were abolished in obese patients under basal conditions but restored during fasting. The circadian rhythm of cortisol was not altered in obesity. A shift of the normal nyctohemeral rhythm of PRL was observed in obese patients, but the normal pattern was restored during fasting.

Adult↗
PubMed1978

Thyrotrophin, prolactin and growth hormone responses to TRH in barbiturate coma and in depression.

The effects of 200 microgram thyrotrophin-releasing hormone (TRH) i.v. on thyrotrophin (TSH), prolactin (PRL), growth hormone (GH) and triiodothyronine (T3) were studied in eight patients with barbiturate coma due to attempted suicide, in the same patients after recovery, in eight depressive patients and in eight normal controls. The patients with barbiturate coma presented normal basal TSH and PRL, elevated basal GH and normal PRL but blunted TSH responses to TRH; their GH concentrations varied widely without consistent relation to TRH administration. The same patients after recovery from coma presented normal TSH and PRL, slightly elevated basal GH, and normal PRL but blunted TSH responses to TRH; in four of these patients, a clear-cut rise in GH (i.e. more than 10 ng/ml) occurred after TRH administration. The depressive patients presented normal basal TSH and PRL, slightly elevated basal GH, and normal PRL but blunted TSH responses to TRH; in four of these patients, a moderated rise in GH (less than 10 ng/ml) occurred after TRH administration. The increment in T3 concentrations 120 min after TRH was found reduced in the comatose patients only. Basal cortisol was measured in all the subjects and found elevated in the comatose patients only. It is concluded that the abnormal TSH and GH responses to TRH observed in patients with barbiturate coma are more likely related to depressive illness than to an effect of barbiturates at the pituitary level. Barbiturates might affect thyroid secretion.

Adolescent↗
PubMed1978

Lactate uptake by inactive forearm during progressive leg exercise.

Eleven male subjects were studied during graded leg exercise from 60 to 270 W. Arterial and venous lactate concentrations were measured from the resting forearm during the exercise and recovery periods. Lactate concentration rose regularly during the work and declined slowly to basal levels after the exercise. The arteriovenous difference rapidly became positive during the exercise, indicating a net uptake of lactate by the nonexercising muscles. The uptake of lactate by the muscle correlated directly with the arterial concentration. After the 5th min of recovery, there was no longer any significant difference between arterial and venous lactate concentrations. It is concluded that 1) nonexercising muscles play a small role in the removal of lactate during exercise and 2) significant removal of lactate from the blood by nonexercising muscles stops soon after the cessation of exercise.

Adolescent↗
PubMed1977

Improved quality control of blood acid-base equilibrium using the daily mean of patients' results: a validation study.

The efficiency of the daily mean of patients' results as a quality control tool for acid-base equilibrium has been studied in three one-month periods. Results for the first two periods were obtained in a stable patient population using tonometry in one period, direct measurement of PCO2 in the other; the third period corresponded to another patient population in which PCO2 was determined by direct measurement. These comparisons allowed demonstration that both methodology and patient populations influenced the optimal truncation limits used to exclude extreme values. Furthermore, the efficiency of the daily mean in itself was poor. Using a cusum plot of the differences of each daily mean from the monthly mean of the daily means, however, dramatically improved this efficiency. So modified, quality control using the daily mean of patients' results represents a useful tool, since the whole analytic process, from blood sampling to result, is checked.

Acid-Base Equilibrium↗
PubMed1977

The endocrinometabolic effects of beclomethasone dipropionate in asthmatic patients.

The endocrinometabolic effects of the aerosol administration of beclomethasone dipropionate (100 microng four times daily) were evaluated in 20 asthmatic patients (11 corticodependent and nine noncorticodependent) during one month. In the noncorticodependent group, aerosol administration of beclomethasone had no statistically significant effect on the results of the glucose tolerance test and the plasma levels of insulin; there was a slight decrease in basal levels of cortisol, but the response of the cortisol level to administration of ACTH remained quite normal. In corticodependent patients, after substitution of aerosol therapy with beclomethasone for the oral therapy with steroids, the depression of adrenal function disappeared, usually quickly (in less than one month), whereas the abnormalities in the results of the glucose tolerance test persisted. Thus, at the dosage used, beclomethasone dipropionate might have minor systemic endocrinometabolic effects.

Adrenal Glands↗
PubMed1976

Pituitary and extrapituitary effects of somatostatin in normal man.

The effects of synthetic linear somatostatin on basal circulating levels on several pituitary and pancreatic hormones, and of glucose and free fatty acids (FFA) were studied in 6 normal men after an overnight fast. A priming intravenous infusion of 250 mug of somatostatin in 18 sec was followed by a constant infusion of 500 mug over a period of 60 min. A decrease in plasma values of GH, prolactin, TSH, insulin and glucagon and in blood glucose was observed during somatostatin infusion, while FFA levels increased progressively. Plasma IRI and blood glucose increased rapidly when the somatostatin infusion was stopped, while FFA decreased progressively; GH, prolactin, TSH and glucagon remained low as compared to basal levels for one hour after the end of the infusion, i.e. until the end of the experiment. A slight but significant increase of LH and ACTH was observed after the end of the infusion.

Adrenocorticotropic Hormone↗
PubMed1976

Effects of testosterone on gonadotrophin responses to synthetic LH and FSH releasing hormone (LRH) in normal men.

LRH tests were performed in 6 adult men with intravenous injections of 25 mug, before and one week after an intramuscular injection of 250 mg testosterone oenanthate (Testoviron Depot). One week after intramuscular injection of Testoviron the tonic secretion of LH was completely suppressed, but the reactivity or the reserve capacity of LH secretion, as tested by LRH, remained unchanged. In contrast, the tonic secretion of FSH and the reactivity of FSH secretion to LRH were both partly suppressed. Three months after the Testoviron injection, the basal levels of LH were still significantly lower than the control values, but the basal levels of FSH were identical to the control values. These data indicate that, in man, the feedback action of testosterone on gonadotrophin secretion could be exerted, at least for LH, at the hypothalamic level rather than at the pituitary level . No significant effects of LRH were noted on the circulating levels of growth hormone and sugar. There was a distinct rise in serum prolactin, which was occasionally significant, within 30 min after LRH injection; this is considered to be without physiological significance.

Adult↗
PubMed1975

A combined radioimmunoassay for glucagon and insulin.

A combined radioimmunoassay for glucagon and insulin in biological fluids is presented. It is based on the use of 131I-glucagon and 125I-insulin tracers and a charcoal-dextran separation procedure. Standard curves, sample determinations and recovery studies gave comparable results whether in the combined or individual assay for glucagon and insulin. The combined assay, especially if supported by a decoding and calculating computer program, offers the advantages that it requires a smaller volume of the material to be sampled, is more economical and less time-consuming.

Adsorption↗
PubMed1975

Failure of parathormone to affect insulin and glucagon release from the perfused rat pancreas.

Parathormone (0.15 U/ml) failed to affect the rate of glucagon and insulin release by the perfused rat pancreas exposed to glucose in either low (3.3 mM) or high (8.3 mM) concentration. Parathormone also failed to interfere with the suppressive effect of glucose (16.6mM) upon glucagon release and its stimulatory action upon insulin secretion. Likewise, the biphasic release of both glucagon and insulin evoked by arginine (10.0 mM) in the presence of glucose (8.3 mM) was unaffected by parathormone. These findings suggest that the endocrine pancreas may not be a target organ for any direct and immediate action of parathormone.

Animals↗
PubMed1975

Effects of oral contraceptive therapy on the circadian patterns of cortisol and thyrotropin (TSH).

The daily variation of serum cortisol and thyrotropin (TSH) has been simultaneously recorded every 30-min. in 4 women taking the same oral contraceptive containing oestrogens and progestogens and in 4 control women. The circadian rhythm of cortisol persisted under contraceptive therapy with about a 2.5 fold elevation of the mean level and amplitude of the basal rhythm. Theoretical equilibrium calculations of the circadian variations of the free, transcortin-bound and albumin-bound cortisol fractions showed that these elevations are explained qualitatively and quantitatively by an oestrogen-induced increase of the same order of the transcortin cortisol-binding sites. As a consequence of the already high saturation of transcortin in normal conditions, the magnitude of the variation of free cortisol level resulting from a burst in cortisol secretion varies with the time of day. The role of albumin as a buffer is thereby emphasized. The early morning maximum, characterizing the normal TSH daily pattern, appeared to be considerably enhanced in women under contraceptive therapy. If the circadian variations of TSH are driven by thyrotropin releasing hormone (TRH), these higher morning peaks probably reflect a higher burst of TRH secretion rather than an increased responsiveness of the pituitary to TRH secretion induced by contraceptive therapy. Finally these results do not support the hypothesis of a regulation of TSH circadian variations by an inhibiotry action of cortisol. Contraceptive therapy does not appear to play a role at the level of the central clock or on the resetting mechanism.

Adult↗