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Biomedical subjects

D Durand

Publications and source records attributed to D Durand.

At least 343 records · Page 19Linked to original sources

A correlative study of immunofluorescence, electron, and light microscopy in immunologically mediated renal tubular disease in man.

Renal biopsy specimens obtained from patients with various chronic nephropathies were studied by immunofluorescence (IF), electron and light microscopy. Of 49 biopsies studied by IF, 22 had granular deposits of IgG and/or C3 along the basement membranes of proximal tubules while 14 had linear and 13 both linear and granular deposits. The possible importance of immunologically mediated renal tubular lesions in chronic nephropathies is discussed.

Basement Membrane↗

[Are surgical renal biopsies useful for clinical prognosis in renal artery stenosis?].

The most significant results show the predominance of arteriolar lesions in the controlateral kidney, The most significant results show the predotients with unilateral renal artery stenosis. and parenchymal lesions of the kidney with stenosis in patients with atherosclerosis. These results do not seem to provide information which would alter the clinical management in any particular case.

Adult↗

The significance of urine phosphate measurements in the early diagnosis of intestinal infarction.

This study has confirmed previous experiments which indicated that inorganic phosphate concentrations rise in body fluids after intestinal infarction. The phosphate clearance ratio is elevated in dogs after occlusion of the superior mesenteric artery, but is not as sensitive as indicator of the presence of a necrotic intestine as the serum or peritoneal fluid phosphate levels. The rise and fall of phosphate levels occur within the first 24 hours after infarction, similar to amylase levels in acute pancreatitis. The renal failure observed in dogs after ligation of the superior mesenteric vein is likely on the basis of hypovolemia and does not seem to result from hyperphosphatemia. Intestinal infarction should be suspected with laboratory evidence of hemo-concentration, marked leukocytosis, an inappropriate metabolic acidosis and elevated serum and peritoneal fluid phosphate levels. In dogs with normal renal function, an elevated urinary phosphate clearance ratio of greater than 0.20, as measured on a spot sample of urine and serum, is also highly suggestive of the presence of this condition, but its absence, by no means, excludes the diagnosis. With these simple laboratory tests, possibly an earlier diagnosis can be made, and timely operation can be an entirely intestine-saving procedure.

Acute Kidney Injury↗

Preinfarction diagnosis of acute mesenteric ischemia by simple measurement of inorganic phosphate in body fluids.

Acute mesenteric ischemia is extremely difficult to diagnose because peritoneal signs are absent until the bowel becomes necrotic and irretrievably damaged. So far the only reliable diagnostic procedure has been mesenteric angiography. The present study verifies that significant elevations of serum inorganic phosphate concentrations occur in dogs after mesenteric occlusion; the authors' initial clinical studies in humans support these experimental findings. Detailed analysis of body fluid and soft tissue phosphate content shows that the high phosphate load originates in the sloughing intestinal mucosa; if this phosphate escapes filtration by the liver it enters the systemic circulation. Simple measurement of the inorganic phosphate concentrations of the serum and peritoneal fluid may lead to earlier diagnosis of acute intestinal ischemia and a successful revascularization procedure to prevent its progression to infarction.

Acute Disease↗

Lymphocytotoxic antibodies and antiglobulins in renal allograft recipients. Correlative study with acute rejection.

In 45 patients who received kidney transplants, both homologous and heterologous human antiglobulins (anti-Ig) and HLA cytotoxic antibodies have been studied before and after transplantation and in some cases after nephrectomy. A similar study has been performed in a control group of 1,019 healthy blood donors and in 130 patients with acute or chronic glomerulonephritis. After transplantation, homologous anti-IgG were found in 60% of the patients, as compared with 3.5% in the healthy blood donors and 21% in patients with various forms of glomerulonephritis. This difference is particularly striking in sera obtained prior to nephrectomy; the presence of anti-IgG and cytotoxic antibodies in the same patient being significantly associated with early transplant failure. Anti-IgA were found in 75% of the patients with transplants and in 37% of the patients with glomerulonephritis. There was no relationship between the anti-IgA and the outcome of the graft. On the other hand, heterologous anti-Ig were unchanged in the three groups investigated. The mechanism of formation of the anti-IgG is not clear. They are probably antibodies against antigenic structures of the patient's own antibodies, previously combined with a soluble antigen or an antigen on the transplant that has undergone molecular transformation in the course of this reaction. Their pathogenic role, although not demonstrated, can be strongly suspected, and, in a practical way, screening for the anti-Ig in kidney transplant recipients could be of value as a prognostic test.

Antibodies↗

Increased level of factor VIII complex in severe arterial hypertension.

Factor VIII complex was studied in patients presenting arterial hypertension. Visceral involvement was quantified using a clinical index calculated from ocular fundus, renal function and left ventricular hypertrophy data. A significant correlation was found between the mean arterial pressure, the visceral involvement and the level of complex VIII. Nevertheless, other data obtained in different patients (Conn's disease) suggest that the visceral involvement (and not the mean arterial pressure) is the main determining factor in the increase of factor VIII complex.

Factor VIII↗

Spontaneous renal arteriovenous fistula and arterial hypertension--conservative treatment and healing.

A case is reported of idiopathic renal arteriovenous fistula in a young adult suffering from arterial hypertension. It was treated by conservative surgery with endo-aneurysmorrhaphy and extrasinusal clamping of the artery supplying the fistula. The post-operative course was uneventful. Arterial pressure returned to normal after 30 months. Diagnosis, therapy and the relationship between hypertension and fistula are discussed.

Arteriovenous Fistula↗

Neuropharmacological regulation of episodic growth hormone and prolactin secretion in the rat.

The effects on GH and PRL secretion of several pharmacological agents known to modify central neurotransmitter action were determined in unanesthetized male rats. Phenoxybenzamine, an alpha-adrenergic blocker (5 mg/kg iv), abolished episodic GH secretion and caused elevation of serum PRL levels. Propranolol, a beta-adrenergic blocker (5 mg/kg iv), had no effect on GH secretion and caused a small but significant depression in PRL levels. Parachlorophenylalanine methyl ester, an inhibitor of tryptophan hydroxylase (300-350 mg/kg ip), resulted in significant inhibition of GH pulsatile secretion and suppressed PRL levels. Methysergide hydrogen maleinate (25 mg/kg iv), a serotonin receptor antagonist, also inhibited GH secretion, but produced a transient stimulation in PRL levels. Atropine sulfate (2 mg/kg iv) caused significant suppression in GH secretion, but had no effect on PRL. Picrotoxin, a gamma-aminobutyric acid antagonist, in a subconvulsive dose of 1-3 mg/kg iv, also depressed GH episodic secretion but did not affect PRL levels. These results indicate that several neurotransmitters, i.e., norepinephrine, serotonin, acetylcholine, and gamma-aminobutyric acid, found in high concentration in the hypothalamus, influence GH and PRL secretion.

Animals↗

[Arterial hypertension in pregnancy: current concepts].

Although the term hypertension in pregnancy is a simple and uncontroversial one, it unfortunately encompasses some ill defined clinical conditions as well as pre-eclampsia. The prime cause of pre-eclampsia is utero-placental ischaemia. Such utero-placental ischaemia is responsible for the hypothetical secretion of a vasopressor agent and for intravascular coagulation. An immunological cause should also be suspected: a study of the immune profile of the kidney has shown that the glomerular capillaries contain immunoglobulins G and M as well as the C3 fraction of complement. Renal biopsies carried out three months after delivery have shown deposits of C3 in the arteriolar walls. During normal pregnancy, there exists a state of stable equilibrium of hormonal, haemodynamic, haematological and immunological factors. It seems that all components of this equilibrium are disturbed in cases of hypertension in pregnancy.

Adolescent↗

Tubular basement membrane deposits in human renal allografts.

In 18 patients who received renal allografts, tubulo-interstitial lesions were studied, according to the types of rejection or the possible recurrence of primary disease. Immunofluorescent (IF) investigation revealed tubular basement membrane (TBM) deposits of IgG and/or C3 and sometimes other components of Complement. The pattern of these deposits was: "linear" in 3 cases, "granular" in 9 cases and "atypical" with linear and granular segments in 6 cases. The IF study of own kidneys of 3 patients, before the transplantation, revealed no TBM deposits. TBM deposits were accompanied by arterial wall deposits of IgM and/or C3 and sometimes C5 in 17 cases. Electron-microscopy study of renal tubules showed thickening, lamellation and/or deposits along the tubular basement membrane. The immunopathogenesis of these deposits was discussed.

Antibodies, Anti-Idiotypic↗

The significance of elevated peritoneal fluid phosphate level in intestinal infarction.

Early diagnosis seems mandatory if the mortality of mesenteric vascular occlusion is to be altered. A model has been developed in which intestinal infarction has been produced by ligation of either the superior mesenteric vein or the superior mesenteric artery. Results of earlier work, using this model, have shown a significant rise in the serum inorganic phosphate level and an associated severe metabolic acidosis. This article has confirmed these results as being statistically significant. In this experiment, a significant rise in the inorganic phosphate level of the peritoneal fluid has been shown in the same model. We suggest that, in the patient with possible intestinal infarction, an elevated serum phosphate level, elevated peritoneal fluid phosphate level, base deficit and leukocytosis may be useful in making an earlier diagnosis of this disease. If an earlier diagnosis is accomplished, the morbidity and mortality of this lethal disease hopefully will be reduced.

Animals↗

Evidence for a role of alpha-adrenergic mechanisms in regulation of episodic growth hormone secretion in the rat.

The role of catecholamines in regulation of episodic GH secretion was investigated in the male rat. Administration of alpha-methyl-p-tyrosine (alpha-MT; 250 mg/kg ip) caused significant suppression of GH bursts and resulted in marked elevation of plasma PRL. Intravenous administration of apomorphine (.03 and .1 mg/kg) had no effect on decreased GH levels, whereas clonidine (150 micrograms/kg) restored GH secretion. Apomorphine significantly reduced PRL levels in alpha-MT-treated rats whereas, clonidine resulted in a further increase in PRL.

Animals↗