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Biomedical subjects

D Durand

Publications and source records attributed to D Durand.

At least 271 records · Page 15Linked to original sources
PubMed1988

Method for continuous measurement of blood metabolite hepatic balance in conscious preruminant calves.

A method of continuous in vivo flow measurement of plasma metabolites through the liver in calves was described. Five 2-wk old male calves were fitted with chronic catheters in the hepatic and portal veins and in the hepatic artery and with electromagnetic blood flow probes in the portal vein and in the hepatic artery. The reliability of measurements was tested during a 3-wk period in which calves were fed milk diets that curdled or did not curdle (uncurdled) in the abomasum. In comparison with a conventional curdled milk diet, the intake of uncurdled milk diet did not modify mean portal vein (47 to 49 ml.mn-1.kg live weight-1) or hepatic arterial (5.6 to 5.7 ml.mn-1.kg live weight-1) blood flows but did influence nycthemeral variations in portal blood flow rates, especially during the second part of the night.

Animals↗
PubMed1988

[Value of the study of circulating adrenergic receptors in the diagnosis and surveillance after surgery of pheochromocytoma].

The purpose of the study was to investigate leukocyte beta adrenoceptors and platelet alpha 2 adrenoceptors in pheochromocytoma. The study concerned nine hypertensive patients, five men and four women (aged 42 +/- 8 years) with a pheochromocytoma demonstrated by high levels of urinary catecholamines and radiological data. Catecholamine plasma levels, assayed by HPLC were wide-ranging: 10.7 to 172.8 nM for noradrenaline and 0.7 to 3.9 nM for adrenaline. In each case the number of leukocyte beta adrenoceptors sites (measured with 125 I-cyanopindolol) significantly decreased: Bmax was 20.6 +/- 2.8 versus 48.5 +/- 1.5 fmol/mg protein in controls (p less than 0.05). In contrast, the number of platelet alpha 2 adrenoceptors sites (measured with 3H-yohimbine) was not modified: 206 +/- 22.6 versus 186.0 +/- 12.1 fmole/mg protein in controls. There was no change in affinity constant (Kd), neither for beta nor alpha2 adrenoceptors. After tumor removal, there was a significant increase in beta adrenoceptor number. We conclude that down regulation occurs in vivo for beta adrenoceptors but not for alpha2 adrenoceptors and that the decrease in leukocyte beta adrenoceptor number is an interesting and suitable index in the management of pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1988

[Gastro-entero-pancreatic production and hepatic uptake of gastrin and somatostatin in the preruminant calf receiving milk proteins or milk serum].

In preruminant calves total splanchnic production of immunoreactive somatostatin and gastrin did not change when casein was replaced by whey protein in the diet, but gastrin secretion was more rapid for the first 3 postprandial hours. Loss during passage through the liver was equivalent to splanchnic production for somatostatin, but was very low for gastrin.

Animals↗
PubMed1988

[Arterial hypertension with hyperkalemia, tubular acidosis and normal renal function: Gordon syndrome and/or pseudohypoaldosteronism type II?].

Basic examination of Mr S., 45 years of age, short in stature and overweight (1.60 m, 76 kg), was carried out because of the mild hypertension (mean AP 125 mm Hg) from which he had suffered for 20 years. The results were as follows: (1) variable hyperkalemia: plasma potassium values were 5.3 to 6.9 mmol/l; (2) normal renal function: serum creatinine 91.5 mumol/l, clearance of inulin 136.6 ml/mn; (3) proximal tubular acidosis: plasma bicarbonate and chloride values were 18.4 and 109 mmol/l, respectively; urinary pH was 7.1 with negative H+ ions urinary excretion (-33 mumol/mn); when plasma bicarbonate level was raised to 26 mmol/l by acute loading, fractional excretion of bicarbonate increased to 19,5 p. 100 while plasma potassium value decreased to 4.2 mmol/l; (4) low PRA (0.29 ng/ml/h) and normal plasma aldosterone concentration (63 pg/ml) with a normal intake of sodium and in a recumbent position. Plasma atrial natriuretic factor (ANF) level was normal: 14 fmol/ml. Intravenous infusion of ANF for 2 h (1 microgram/mn) induced the expected increases in urinary flow rate, and sodium and potassium excretions (+226, +307 and +171 p. 100, respectively). Intravenous infusion of isotonic saline (2 l in 2 h) and oral administration of fludrocortisone acetate for 4 weeks (400 micrograms per day) resulted in a normal decrease in PRA and plasma aldosterone concentration, a normal rise in plasma ANF level (22 and 42 fmol/ml) while slightly increasing AP without improving bicarbonaturia and acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis, Renal Tubular↗
PubMed1988

[Segmental renal hypoplasia of an adult originating from pseudo-tumor hyperreninism].

A 38 year-old man was admitted for severe hypertension with hypokalemia. Blood pressure was 180-120 mmHg, funduscopic examination revealed grade II retinopathy and left ventricular hypertrophy was present. Laboratory data disclosed: natremia = 140 mmol/ml, kalemia = 2.8 mmol/l, chloride = 105 mmol/l, bicarbonate = 30 mmol/l, creatinine clearance = 100 ml/mn, natriuresis = 140 mmol/day, kaliuresis = 80 mmol/day. Intravenous pyelography was normal. Angiography revealed a defect in the mid third of the right kidney without arterial abnormalities. Study of renin angiotensin aldosterone system showed: plasma renin activity: peripheric blood = 36 ng/ml/h (normal range I to 2), right renal vein = 30 ng/ml/h. Left renal vein = 18 ng/ml/h, inferior cava vein = 19 ng/ml/h. Plasma aldosterone level = 86 ng/100 ml (normal range 10 to 15). Captopril acute administration was followed by a fall of BP to 70-50 mmHg at 2 hours. Right nephrectomy was performed and revealed an ischemic retracted cortical area without necrosis nor tumoral aspect. The day after BP was 140/80 mmHg. Eight days after, kaliemia was 4.2 mmol/l, PRA was 0.5 ng/ml/h. Light microscopy showed that affected area was sharply delimited from surrounding normal tissue. In this area, glomeruli were present and seemed more numerous as usual; interstitial fibrosis and infiltrates of inflammatory cells were also noted. The main fact was tortuosities of intralobular arteries, thickened, with intimal proliferation. There was a pelvic recess near this cortical tissue. Immunofluorescence findings: antirenin serum fixed on JGA but also on interlobular arterial walls and on peritubular interstitium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Lateralization of renin secretion in renovascular hypertension with bilateral arterial stenosis].

A retrospective analysis of peripheral and renal vein plasma renin activity has been performed in 9 patients with bilateral renal artery stenosis (3 fibromuscular dysplasia and 7 atherosclerosis). In all cases angiography showed a reduction of the arterial diameter of more than 70 p. 100. The renal artery was occluded in 3 cases. All patients received a constant sodium diet (100 mEq/day). Peripheral PRA values were classified as normal or low in 6 cases (less than 2.8 ng/ml/h) and high in one case (greater than 2.8 ng/ml/h): this values concerned 2 cases with renal artery occlusion and 1 case with a narrowing of 90 p. 100. Renal venous renin ratio of 1.5 or more has been found in 8 cases. In one case, the stenosis was quite symmetrical (70 p. 100) and the ratio less than 1.5. The secretion index has been calculated as the ratio between the venoarterial difference of both affected and unaffected side over the arterial value of PRA (V-A/A). On the more stenosed side, was found a V-A/A ratio of 0.5 or more. This ratio is particularly high in case of artery thrombosis, but there is no correlation between the ratio and the degree of stenosis. On the contralateral side, where the lesions were less important, the V-A/A ratio was low, ranging from 0 to 0.2; this estimation of renin secretion was found despite a significant stenosis on the angiography. 7 patients underwent PTA or surgery. 2 kidneys with arterial thrombosis were nephrectomized. In 5 cases the surgical treatment is performed on the 2 sides during the same procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Transcriptional activity of the gibbon ape leukemia virus in the interleukin 2 gene of MLA 144 cells.

The gibbon ape leukemia virus (GALV)-infected T-cell line, MLA 144, constitutively makes the lymphokine, interleukin 2 (IL 2), without stimulation by antigen or mitogen. This line contains two GALV insertions in the IL-2 gene: one in the 3' untranslated region of the gene and one 1200 bp 5' to the gene. It is likely that one or both of these viral insertions is(are) involved in activation of IL-2 expression. We investigated the ability of sequences within the LTR of MLA 144 cells (GALV-MLA) to act as transcriptional elements and have demonstrated here the presence of cis-acting sequences in the GALV LTR capable of enhancing transcription of the GALV promoter as well as two heterologous promoters, SV40 early and IL-2. The results indicate that insertion of the enhancer element(s) alone is not sufficient to activate IL-2 expression but can enhance levels of IL-2 expressed from the activated gene.

Animals↗
PubMed1987

Activation of the inspiratory intercostal muscles by electrical stimulation of the spinal cord.

Electrical stimulation of the spinal cord was evaluated as a method of activating the inspiratory intercostal muscles. Studies were performed in anesthetized dogs after hyperventilation-induced apnea. A stainless steel electrode, rubberized along its entire length except for 2 to 3 mm at the distal tip, was introduced epidurally onto the dorsal surface of the thoracic spinal cord. Stimulating electrodes were also placed in each hemidiaphragm. Intercostal electromyograms, inspired volume, and thoracoabdominal movements were monitored. The inspiratory capacity was determined in each animal as the volume required to achieve an airway pressure of +25 cm H2O during passive lung inflation. Spinal cord stimulation at the T2-T3 spinal level resulted in maximal inspired volume generation and electrical activation of the parasternal, external, and internal intercostal muscles of the upper and midrib cage regions as determined by electromyograms. Intrathoracic pressure swings increased progressively with increasing stimulus amplitude and frequency until plateaus were reached at 6 mA and 40 Hz, respectively. Postphrenicotomy spinal cord stimulation resulted in expansion of the rib cage and reduction in circumference of the abdominal compartment. Inspired volumes during spinal cord stimulation were 537 +/- 49 ml (prephrenicotomy, prone), 347 +/- 19.6 ml (postphrenicotomy, prone), and 303 +/- 30.6 ml (postphrenicotomy, supine). Bilateral diaphragm activation alone resulted in inspired volumes of 404 +/- 39 ml. Combined diaphragm and postphrenicotomy spinal cord stimulation (supine) resulted in an inspired volume of 712 +/- 72 ml, which approximated the inspiratory capacity (803 +/- 35 ml). Our results suggest that spinal cord stimulation may be a useful physiologic and clinical tool to produce coordinated contraction of the inspiratory intercostal muscles.

Animals↗
PubMed1987

[Characterization of the stimulant effect of 2 neuropeptides (thyroliberin (TRH) and vasoactive intestinal peptide (VIP)) on the secretion of the growth hormone in the rat].

The effects of thyrotropin-releasing hormone (TRH) and vasoactive intestinal peptide (VIP) on growth hormone (GH) secretion were investigated in vivo in freely moving, intact or mediobasal hypothalamic-lesioned rats and in vitro in incubation or superfusion systems of anterior pituitary tissue. In vivo, the two peptides induced a rapid increase of plasma GH levels in freely moving animals, bearing an extensive lesion of the mediobasal hypothalamus including the median eminence. VIP, but not TRH, was also effective in intact animals. In vitro, TRH and VIP stimulated GH release from incubated or superfused rat pituitaries in a concentrated manner: apparent affinity was 1.22.10(-8) M for TRH and 2.5.10(-9) M for VIP. These findings indicate that TRH and VIP exert a direct stimulatory action on somatotrophs, but that the effect of TRH (not observed in freely moving, intact rats) may be modulated by still other unidentified hypothalamic neurohormones.

Animals↗
PubMed1987

[First consultations in nephrology. Comparison of 2 multicenter studies conducted at a 5-year interval].

An investigation of "kidney outpatient" first consultations carried out in 1985 with the cooperation of 19 nephrological teams distributed all over France. Each team had taken part in a similar investigation in 1980. The work allowed to collect 1200 records. Analysis of the main results is presented. The comparison between the 1980th and the 1985th investigations shows a remarkable stability of the results, but suggests two new and interesting features: the progress of Dip-stick studies and serum creatinine concentration in general practice and the decreasing part taken by hypertension in "kidney disease out-patient" activity in 1985.

Adult↗