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Biomedical subjects

V Lemaitre

Publications and source records attributed to V Lemaitre.

At least 19 recordsLinked to original sources
PubMed2003

Molecular dynamics simulations on the first two helices of Vpu from HIV-1.

Vpu is an 81 amino acid protein of HIV-1 with two phosphorylation sites. It consists of a short N-terminal end traversing the bilayer and a longer cytoplasmic part. The dual functional role of Vpu is attributed to these topological distinct regions of the protein. The first 52 amino acids of Vpu (HV1H2) have been simulated, which are thought to be embedded in a fully hydrated lipid bilayer and to consist of a transmembrane helix (helix-1) connected via a flexible linker region, including a Glu-Tyr-Arg (EYR) motif, with a second helix (helix-2) residing with its helix long axis on the bilayer surface. Repeated molecular dynamics simulations show that Glu-28 is involved in salt bridge formation with Lys-31 and Arg-34 establishing a kink between the two helices. Helix-2 remains in a helical conformation indicating its stability and function as a "peptide float," separating helix-1 from the rest of the protein. This leads to the conclusion that Vpu consists of three functional modules: helix-1, helix-2, and the remaining residues toward the C-terminal end.

Amino Acid Sequence↗
PubMed2002

[Camptocormia: a sign of axial myopathy. Report of 7 cases].

PURPOSE: Camptocormia or progressive lumbar kyphosis is an anterior bend of the trunk. It appears in orthostatism or while walking and is reducible in the decubitus position. It concerns patients older than 60 years of age. It is due to a fatty degeneration of the paravertebral muscles, although the physiopathology remains unclear. METHODS: We report seven cases of camptocormia revealing authentic myopathies. RESULTS: Our observations concern five women and two men of 55 to 72 years of age. All patients present lumbar kyphosis and had a fatty involution of the paraspinal muscles on the muscular MRI. Four patients fulfilled the Bohan and Peter criteria of polymyositis and dermatomyositis. In the other cases paravertebral muscular biopsies led to the diagnosis of a congenital myopathy, a mitochondrial myopathy and an amyloid myopathy. Four patients received a corticosteroid-immunoglobulins or cyclosporin regimen. An improvement in the camptocormia was observed in three cases. In the other cases the treatment consisted of chemotherapy on account of severe nephrotic syndrome, a coenzyme-Q treatment for the patient with mitochondrial myopathy and only physiotherapy in the case of congenital myopathy, but without positive effect on camptocormia. CONCLUSION: Camptocormia appears as a muscular symptom that may reveal an axial myopathy due to multiple and varied pathologies. Thus, the discovery of camptocormia requires an aetiological investigation in order to propose an adequate treatment, which should be associated with physiotherapy.

Aged↗
PubMed1998

Renal thrombotic microangiopathy in systemic lupus erythematosus: clinical correlations and long-term renal survival.

BACKGROUND: Renal thrombotic microangiopathy (TMA) is an uncommon vascular complication of systemic lupus erythematosus (SLE). Its clinical symptoms and impact on renal survival remain unclear. METHODS: Eight patients aged 25 +/- 6 years with biopsy-proven renal TMA and at least four ARA criteria for the diagnosis of SLE were retrospectively studied over a 7-year period. RESULTS: All patients presented with renal failure (creatinine 3.3 +/- 2.1 mg/dl), six had proteinuria (2.5 +/- 1.3 g/day) with microscopic haematuria in four cases. Six patients had hypertension, which was severe in five cases. Renal histology disclosed arterial and/or arteriolar thrombosis with parietal thickening without angeitis (8 patients), glomerular microthrombi (3 patients), and vascular fibrin deposits (5/6 patients). In two cases, vascular lesions were associated with a mesangial or a proliferative glomerulonephritis. Thrombocytopenia was present in four patients with haemolytic microangiopathic anaemia in one case. Lupus anticoagulant (LA) was detected in five of eight patients, who also had anticardiolipin antibodies (3/7 patients) and/or were positive for VDRL (3/6 patients). Four patients with LA experienced arterial thrombosis and/or repeated spontaneous abortions. Treatment consisted of corticosteroids (8 patients), cytotoxic drugs (4 patients), plasma exchanges and/or intravenous immunoglobulins (4 patients) and antiplatelet and/or anticoagulant therapy (3 patients). Two patients recovered normal renal function and five had persistent renal insufficiency. One patient started haemodialysis on admission and died of sepsis 2 months later. CONCLUSIONS: TMA may be the sole renal complication in SLE and is not usually associated with haemolytic microangiopathic anaemia. In our series renal survival was influenced by the extent and severity of vascular lesions. Despite a frequent association with antiphospholipid antibodies, pathophysiological mechanisms of renal TMA in SLE remain unknown. Renal histology is mandatory for the diagnosis and the prognostic evaluation of renal vasculopathy in SLE.

Adult↗
PubMed1992

Acute renal failure after the use of angiotensin-converting-enzyme inhibitors in patients without renal artery stenosis.

During a 4-year period, acute renal failure was observed in 27 patients (mean age 65 years) treated by various angiotensin-converting-enzyme (ACE) inhibitors for hypertension, heart failure, or a combination of both. None had significant renal artery stenosis on angiography. Overt volume depletion was present in 21 and hypotension in 12 cases. All patients received diuretic therapy and/or a low-salt diet. Other facilitating factors included cardiac failure, pre-existing chronic renal insufficiency, combined therapy with non-steroidal anti-inflammatory drugs, and diabetes mellitus. Twenty-two patients had two or more of these factors at presentation. A renal biopsy performed in 10 cases showed severe arteriosclerosis of small renal arteries in eight and acute tubular necrosis in five instances. Therapy comprised volume expansion, and withdrawal of diuretics and, except in two patients, of ACE inhibitors. Twenty-one patients recovered normal renal function, two died, and permanent renal damage remained in four. These results suggest that sodium depletion has a critical role in inducing acute renal failure, whose outcome is not always benign. A combination of diuretics and ACE inhibitors should be prescribed with caution, especially in older patients with small as well as with large renal vessel disease.

Acute Kidney Injury↗
PubMed1990

[Renal cholesterol embolism. Apropos of 13 cases].

Between January 1981 and April 1988, histologically proven renal cholesterol embolism was diagnosed in 13 men over 60 years of age with a previous history of hypertension and atherosclerosis. Six patients developed acute renal failure, usually induced by a triggering factor such as angiographic procedure or anticoagulation, and associated with peripheral and visceral cholesterol embolism, eosinophilia and a high sedimentation rate. In this group of patients, whose protean clinical manifestations and laboratory data mimicked necrotizing angiitis despite the absence of antineutrophil cytoplasmic antibodies, skin lesion biopsy established the diagnosis and made renal biopsy unnecessary. Six patients had chronic renal failure and elevated sedimentation rate, and the last patient had isolated microhematuria. In these 7 patients, percutaneous renal biopsy was an adequate procedure for the diagnosis of cholesterol embolism. As medical management of cholesterol embolism is essentially preventive, these unusual presentations must be emphasized.

Acute Kidney Injury↗
PubMed1987

Multiple myeloma and severe renal failure: a clinicopathologic study of outcome and prognosis in 34 patients.

Renal failure (RF) occurring in the course of multiple myeloma is often judged irreversible and generally considered an ominous complication. The aim of the present study was to re-evaluate the outcome, triggering conditions and prognostic factors of severe RF in a series of 34 patients, 33 to 90 years old. RF was totally reversible in 7 patients and partially reversible in 9 although 6 of them had to be temporarily dialyzed. However, the improvement in renal function was often very slow as indicated by an average recovery time of 115 days. The high rate of RF reversibility was associated with markedly lengthened survival. Review of triggering events confirmed the leading role of dehydration and hypercalcemia, but further suggested that intake of nonsteroidal anti-inflammatory drugs and renal infection might play a part in the development of RF. Systematic statistical analysis of potential prognostic factors showed that the outcome was significantly more severe in females, but age, myeloma characteristics including tumor mass, calcemia, and triggering events had no predictive value. The most reliable prognostic indicators were provided by analysis of kidney biopsy performed in 30 patients. Complete recovery from RF was observed only in the absence of global tubular atrophy and interstitial damage. In contrast, cast-induced tubular obstruction detected by the presence of Tamm-Horsfall protein in urinary space of glomeruli did not seem to influence the outcome of RF. Finally, we analyzed the prognostic value of immunochemical properties of light chains (LC). Lambda LC were unexpectedly detected in 2 of 3 patients, as compared to a ratio of 1 to 3 in the population of normal and monoclonal Ig, but LC type did not correlate with the course of RF. Isoelectric points of LC measured in 32 patients were dispersed from 5.2 to 8.9 and bore only weak prognostic significance. These results underline the value of kidney biopsy and justify aggressive treatment including dialysis and chemotherapy.

Acute Kidney Injury↗
PubMed1985

[Acute renal insufficiency and accelerated arterial hypertension of renovascular origin: treatment by endoluminal angioplasty. Apropos of 2 cases].

In 2 patients with malignant hypertension and acute renal failure due to renal artery stenosis in a solitary functioning kidney, percutaneous transluminal angioplasty was used to dilate the stenotic renal artery. In both cases, hypertension resolved and renal function significantly improved. Follow-up angiographies revealed the continued patency of the dilated vascular segments.

Acute Kidney Injury↗
PubMed1984

[X-ray computed tomography in the diagnosis of non-advanced stages of renal polycystosis in adults].

At early of non-advanced stages, the diagnosis of adult type polycystic disease may be very difficult using standard morphological techniques: IVU, echotomography. The CT scan is sometimes a decisive diagnostic feature when it shows diffuse invasion of parenchymal tissues by large numbers of cysts, certain measuring only millimetres. Its contribution is emphasised in five cases where the diagnosis was only suspected or envisaged by IVU and echotomography. In 4 of these cases the diagnosis of polycystic disease was confirmed by CT scan.

Adult↗
PubMed1983

Acute interstitial nephritis due to drug hypersensitivity. An up-to-date review with a report of 19 cases.

The clinical, biologic, and pathologic features and the course and treatment of acute interstitial nephritis (AIN) due to drug hypersensitivity are reviewed. The authors report 19 additional cases of AIN, outlining some particular and unusual features. The drugs most often responsible now are penicillins and cephalosporins, cotrimoxazole, thiazide diuretics, glafenin and its derivatives, and nonsteroid anti-inflammatory agents. Diagnosis of AIN should be considered in any case of rapidly progressive renal failure occurring during drug therapy, especially when fever, skin rash, arthralgias, macroscopic hematuria, and blood or urinary eosinophilia are present. In the absence of the preceding symptoms, systematic early renal biopsy may be helpful to detect intersitial infiltrates containing lymphocytes, plasma cells, and eosinophils and/or granulomas with epithelioid cells. Immunologic tests are inconstantly positive. Their sensitivity and specificity often are doubtful in the absence of precise knowledge of the pathogenetic factors involved. Recovery may be hastened in some cases by corticoid therapy. Recurrence of the disease will be avoided by definitive suppression of offending and related drug(s).

Acute Disease↗
PubMed1983

Drug-induced granulomatous interstitial nephritis.

Among 22 cases of drug-induced acute interstitial nephritis (AIN), noncaseating interstitial granulomas were found in eight cases (36%). Acute renal failure (ARF), oliguric in three patients, appeared within 1-20 days after the beginning of therapy. Clinical symptoms suggesting a hypersensitivity reaction were unusual, marked blood eosinophilia was absent, and immunologic tests were inconstantly positive. The discovery of interstitial granulomas may be a clue to the diagnosis of drug-induced AIN, especially when the inflammatory infiltrates do not contain eosinophils. Since significant residual renal impairment may be observed the benefit of early steroid therapy must be debated.

Adolescent↗