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Biomedical subjects

J Ducobu

Publications and source records attributed to J Ducobu.

At least 73 records · Page 4Linked to original sources
PubMed1980

Renal responsiveness to parathyroid hormone in a case of nonfamilial hypophosphatemic osteomalacia.

Plasma immunoreactive parathyroid hormone level, urinary excretion of adenosine cyclic 3',5'-monophosphate (cyclic AMP) and the sensitivity of the renal tubule to calcium infusion and to parathyroid extract were investigated in a patient with nonfamilial hypophosphatemic osteomalacia. Plasma immunoreactive parathyroid hormone concentration was normal and basal urinary excretion of cyclic AMP was increased. Renal cortical adenylate cyclase, as measured by urinary cyclic AMP excretion, was certainly as sensitive to exogenous parathyroid extract as in normal subjects. After a previous calcium infusion, a greater parathyroid-hormone-sensitive component of phosphorus transport in the kidney was present than in two control subjects. Our results indicate that in nonfamilial hypophosphatemic osteomalacia the renal tubule could be hyperresponsive to parathyroid hormone.

Calcium↗
PubMed1979

[The role of prostaglandins in the renal regulation of blood pressure (author's transl)].

In response to ischaemic or vasoconstrictor stimuli the kidney reacts by synthesising prostaglandins (PG) which modify local vascular tone. They induce a compensatory vasodilatation and direct the blood flow towards the internal cortex. It is thus not necessary to attribute a systemic role to PG in order to understand their haemodynamic action. This explains the natriuresis following the injection of PG both in the animal and in man. Nevertheless the direct effet of PG upon the tubular reabsorption of sodium remains controversial since very different experimental models lead to contradictory conclusions. Despite these disparate data, it is probable that PG are intimately involved in the pathogenesis of hypertension. A lack of PG or a deficiency in their metabolism may be responsible in essential hypertension.

Angiotensin II↗
PubMed1976

Effects of hypercalcemia on water and sodium excretion by the isolated dog kidney.

The effects of acute hypercalcemia on hemodynamics and on water and sodium excretion were studied on the blood-perfused isolated dog kidney. This model advantageously eliminates various factors which modify medullary osmolality and intrarenal hemodynamics, as well as collecting duct permeability. Calcium ion directly inhibits sodium reabsorption in the proximal tubule and in the ascending limb of Henle's loop, leading to increased sodium excretion rate and to decreased free water generation. The vasoconstrictive action of calcium, leading to decreased glomerular filtration rate, may mitigate the strong natriuretic effect of this ion.

Animals↗
PubMed1976

Interactions between furosemide and vasopressin on hemodynamics and on water excretion by the isolated dog kidney.

The effects of furosemide were studied on isolated dog kidneys in the absence and in the presence of vasopressin. In the latter condition, furosemide did not modify renal blood flow and glomerular filtration rate while both parameters were decreased by the drug in the absence of vasopressin, as they were also reduced by vasopressin alone. This would indicate direct vasoactive effects of furosemide, depending on the previous tone of the vasculature. In the absence of vasopressin, furosemide decreased free water clearance through inhibition of sodium reabsorption in the ascending limb of Henle's loop. On the other hand, in the presence of vasopressin, furosemide increased free water clearance, presumably through reduction of water reabsorption in the collecting duct by enhanced distal tubular flux.

Animals↗
PubMed1976

Comparative study of plasma cortisol evolution in TRH or placebo injected patients with or without thyroid disease.

The plasma cortisol evolution under TRH has been compared in 27 euthyroid, 12 hyperthyroid and 5 patients with hot nodules and in 15 control individuals receiving a placebo or sham injection. The results showed no statistical difference in plasma cortisol evolution between the groups, suggesting no influence of the thyroid status or TSH secretion on the spontaneous fall of cortisol level during the time of the test.

Clinical Trials as Topic↗
PubMed1975

Effects of indomethacin on renal hemodynamics and on water and sodium excretion by the isolated dog kidney.

Blood-perfused isolated dog kidneys demonstrate steady increases in blood flow and in water and sodium excretion which could be attributed to the accumulation of renal prostaglandins in the perfusing blood. This hypothesis was tested by adding indomethacin, a potent inhibitor of prostaglandins synthesis, to the perfusing blood. Indomethacin completely prevented the vasodilation observed in control kidneys, without affecting glomerular filtration rate. Urine volume was not modified but sodium excretion was enhanced while the steady free water clearance increment observed in the control kidneys was depressed by indomethacin. The sum of sodium and free water clearances which, in the absence of antidiuretic hormone, constitutes an index of the part of the filtered load of solutes which escapes proximal tubular reabsorption, was not modified by indomethacin. Finally, indomethacin partially maintained the osmotic cortico-papillary gradient which was abolished after 2 hrs perfusion in control kidneys. These data suggest that prostaglandins accumulation in the blood is probably the major cause of the vasodilation taking place in isolated blood-perfused kidneys. This vasodilation does not account for decreased proximal reabsorption but partially explains the ADH-resistant diabetes insipidus developing in the isolated kidney. Moreover, indomethacin inhibits sodium reabsorption in the ascending limb of Henle's loop and increases water transport in the collecting duct.

Animals↗
PubMed1975

Contribution of kidney basement membranes and collagen to the urinary excretion of hydroxylysyl glycosides.

Glucosyl-galactosyl-hydroxylysine and galactosyl-hydroxylysine are two substances present only in collagen and in basement membranes. The purpose of this study is to estimate to what extent the kidney contributes to urinary hydroxylysyl glycoside excretion. "In vitro" perfusion of isolated kidneys allows the measurement of hydroxylysyl glycosides independently of the important amount of interstitial collagen present in the whole body. It is shown that the kidney parenchyma contributes no more than 10 percent of the glycosylated hydroxylysine excreted in urine. GBM is not the only renal source of glucosyl-galactosyl-hydroxylysine in urine. Tubular basement membrane and intersitial collagen of kidney may contribute to the excretion by the isolated organ.

Animals↗
PubMedDate not supplied

[Hypokalemic thyrotoxic periodic paralysis: a case report].

A 25-year-old Caucasian man is admitted to hospital because of severe hyperthyroidism. Soon after his admission, he develops a lower limbs proximal muscles paresis with tendinous hyporeflexia. He has presented similar episodes in the previous months. Serum potassium level is 2.9 meq/l whereas it was 4.1 meq/l a few hours before. The patient receives intravenous potassium and propranolol. He will not develop a similar episode afterwards. Hypokalemic thyrotoxic periodic paralysis associated with Basedow's disease is diagnosed. Hypokalemic thyrotoxic periodic paralysis is a very rare cause of intermittent muscular weakness in the young Caucasian male. The frequency of this entity is at least ten times higher in Asiatic hyperthyroid people. Its physiopathology involves intracellular potassium shifts in which Na/K ATP-ases of cell membranes, the number and the activity of which increase in hyperthyroid people, seem to play a major role. Treatment consists of correction of hyperthyroidism and administration of potassium during the acute episode Propranolol is efficient in preventing recurrent episodes of paralysis. Points of comparison between hypokalemic thyrotoxic periodic paralysis and hypokalemic familial periodic paralysis are discussed.

Adult↗
PubMedDate not supplied

Klebsiella and E. coli liver abscess associated with aerobilia: a case report.

Pyogenic liver abscesses are commonly caused by biliary tract infections. We report here a case of liver abscess developed secondary to a biliary-enteric fistula. A 83 year old diabetic woman was admitted because of sepsis due to Klebsiella pneumoniae and E. Coli and with upper right quadrant pain. Six months before admission, a laparoscopic cholecystectomy was performed. The abdominal sonography showed a liver abscess associated with an important aerobilia. The Magnetic Resonance Cholangiography showed a choledocho-colic fistula with an important inflammatory background. There was no evidence of neoplasia or inflammatory bowel disease. The evolution was marked by the development of urinary and bronchial tract infection due to Klebsiella. Septic metastasis are characteristics of Klebsiella liver abscesses. Percutaneous drainage associated with a intravenous antibiotherapy was performed.

Aged↗
PubMedDate not supplied

[Dyslipidaemia and diabetes mellitus].

Cardiovascular diseases are the main complications in diabetes. The lipid pattern includes high triglycerides, low HDL and increased small dense LDL. The treatment strategy is based upon the European Guidelines which insist on global risk evaluation and recommend more severe lipid targets for diabetic than for non diabetic patients. After changes of lifestyle and control of risk factors, statins or fibrates are the drugs of choice, even if fibrates have specific impact on patients with diabetes or the metabolic syndrome.

Clofibric Acid↗