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Biomedical subjects

P F Westeel

Publications and source records attributed to P F Westeel.

At least 19 recordsLinked to original sources
PubMed2001

[MELAS syndrome (mitochondrial encephalopathy with lactic acidosis and stroke-like episodes].

BACKGROUND: The MELAS syndrome (Mitochondrial Encephalopathy, Lactic Acidosis and Stroke-like episodes) belongs to the category of mitochondrial disorders. The most common molecular etiology of the syndrome is a mutation A to G transition at base pair 3243 in the mitochondrial genome. The phenotype is varied and depends on the proportion of DNA muted and which organ on aerobic metabolism suffers most. CASE-REPORT: An 17 year-old woman had successively neurosensory hearing loss, renal disease, cardiomyopathy, diabetes mellitus, lactic acidosis and stroke-like episodes that evoked a MELAS syndrome. DISCUSSION: The skin manifestations of patients with MELAS syndrome are scaly, pruritic, diffuse erythema, reticular pigmentation, moderate hypertrichosis, seborrheic eczema, atopy and vitiligo. Our patient presented severe hirsutism and reticular pigmentation of the limbs. No abnormal histologic and electron microscopic findings were noted in the skin or the follicles involved.

Adolescent↗
PubMed2000

[Renal and hypertensive complications of extracorporeal lithotripsy].

HISTOLOGICAL AND FUNCTIONAL CONSEQUENCES OF ESWL: Extracorporeal shock wave litotripsy is now used for the treatment of about 90% of stones. Because of the nonpunctual delivery of energy into the stone, a small volume of renal parenchyma is injured, giving rise to a fibrous scar which can be visualized by morphological techniques such as magnetic nuclear resonance. Isotopic techniques point out a 15% reduction of renal plasma flow on the side of the litotripsy. For a majority of patients, this alteration is transient. HYPERTENSION: In a few cases, abrupt onset of transient hypertension has been reported in clear relation with a compressive perirenal hematoma. The causal effect of ESWL on late occurrence of permanent hypertension is however still uncertain, probably because of the difficulty to show that this occurrence is not related to the older age of the patient alone. The FDA sponsored multicentric study begun in 1993 should solve this issue in the future. PATIENTS AT RISK: Recent articles suggest that altered renal function prior to ESWL would predict late occurrence of hypertension and worsening of renal failure. Furthermore, age and the resistance index of arcuate or interlobular renal arteries (measured by Doppler) could help to screen the patients at risk of developing hypertension. Practical attitude: In practice, renal function and blood pressure should be carefully monitored in patients aged over 60 and/or who have a serum creatinine > 300 mumol/l.

Acute Kidney Injury↗
PubMed2000

[Renal osteodystrophy (1): invasive and non-invasive diagnosis of its pathologic varieties].

1. Renal osteodystrophy is a general term encompassing all the disturbances of the phosphocalcic metabolism and their associated bone and soft tissue abnormalities, which progressively occur in chronic renal failure. In this article we detail their main histopathological and etiopathogenic aspects as well as their invasive and non invasive diagnostic approach. 2. Osteitis fibrosa is characterized by extensive medullary fibrosis and osteoclastic hyperresorption linked to PTH hypersecretion. 3. Adynamic bone disease is mainly related to iatrogenic oversuppression of PTH secretion. It is favored by aluminum overload which directly inhibits the osteoblasts. It is characterized by a low bone formation rate without primary mineralization defect so that the osteoid seam thickness is normal or low, in contrast to osteomalacia in which by definition osteoid thickness is increased. 4. Osteomalacia is mainly due to aluminum intoxication, vitamin D insufficiency, hypocalcemia, acidosis and exceptionally to hypophosphatemia. 5. The differential diagnosis between the histopathological entities may be oriented on clinical, radiological and biochemical means. Only the bone biopsy can make the diagnosis with certainty. This latter is however necessary for appropriate treatment only in the patients who have been exposed to aluminum and who are symptomatic or hypercalcemic in order to distinguish severe osteitis fibrosa from aluminic bone disease, and more particularly from mixed osteopathy. Indeed surgical parathyroidectomy in patients with mixed osteopathy associating bone hyperremodeling and mineralization defect with inappropriately thick osteoid seam may induce fracturing low turn over aluminic bone disease.

Bone and Bones↗
PubMed1999

Renal and hypertensive complications of extracorporeal shock wave lithotripsy: who is at risk?

Extracorporeal shock wave lithotripsy (ESWL) is now used in the treatment of about 90% of renal and ureteral stones. Because of the non-punctual delivery of energy to the stone, a small volume of renal parenchyma is injured giving place to a fibrous scar which can be shown by highly resolutive imaging techniques like magnetic nuclear resonance. Isotopic clearances point to a reduction of 15% in the renal plasma flow on the side of the lithotripsy, but this alteration appears to be transient in nature. In a few cases an abrupt onset of transient hypertension has been reported in clear relation to a compressive perirenal hematoma. The responsibility of ESWL in the late occurrence of permanent hypertension is, however, still uncertain, probably because of the difficulty in showing that this occurrence is not only related to the older age of the patient. The American Food and Drug Administration-sponsored multicentric study begun in 1992 should solve this issue in the future. Recent articles suggest that altered renal function prior to ESWL would predict the late occurrence of hypertension and worsening of renal failure. Furthermore, age and the resistance index of arcuate or interlobar renal arteries (measured by Doppler) could help to screen patients at risk of developing hypertension. In practice in patients over 60 years of age and/or with a plasma creatinine of >to 300 micromol/l, ESWL should be performed with caution, and renal function and blood pressure should be carefully monitored.

Animals↗
PubMed1999

[Factors in the progression of renal insufficiency during the 2 years preceding the use of dialysis].

UNLABELLED: The respective contribution of sex, type of nephropathy, degree of proteinuria, blood pressure, protein and sodium daily intake, lipid profile, protidemia, hemoglobinemia, acidosis and CaPO4 product on the rate of renal failure progression is debated. The link between these parameters and the decrease of creatinine clearance, delta Ccr (according to Cockroft) was assessed in uni and multivariate analysis in a population of 49 patients (26 men, 23 women; age 60 +/- 15 years, weight 73 +/- 15 kg) selected out of 173 presently treated hemodialysis patients on the basis of availability of a quarterly follow-up for two years before starting dialysis. The patients were advised a moderate protein and salt restriction which could be retrospectively assessed (on urinary excretion of urea and sodium) at respectively 0.82 g/kg/day and 6.5 g/day. The two years delta Ccr was 14 +/- 14 ml/min. It was not different in men and women (specially when expressed in % of initial value). This decrease in Ccr was neither significantly different in glomerular disease (17 +/- 8, n = 14), diabetic nephropathy (12 +/- 6, n = 7), nephroangiosclerosis (15 +/- 8, n = 5), interstitial nephritis (12 +/- 10, n = 14), and PKD (11 +/- 12, n = 9). Patients with antihypertensive drugs (n = 42) had a faster progression than those without drugs (n = 7): delta Ccr = 15 +/- 14 vs 7 +/- 7 ml/min (p < 0.05) in spite of comparable blood pressure but with higher proteinuria. Linear regression of delta Ccr with the initial and two year averaged values of the quantitative parameters showed a significant positive link for both values with cholesterol, hemoglobin and proteinuria and a negative one with protidemia. A positive link was observed with the initial value of bicarbonate and the two year mean of diastolic and mean blood pressures. No link at all was observed with urea and Na excretion, CaPO4 product and triglycerides. Multiple regression disclosed a significant link only for protidemia (negative with both initial and two years averaged value), diastolic BP (only for the two year averaged value and hemoglobinemia (for the initial value). When the patients were classified according to a threshold value of their protidemia, DBP, hemoglobinemia, and cholesterolemia those with the combination of two risk factors of progression (pro-tidemia < 66 g/l, DBP > or = 90 mmHg, hemoglobinemia > 11 g/dl, proteinuria > 3g/d, CT > 5 mmol/l) had a significantly greater decrease of Ccr than those with the three other combinations at the exception of the association of low protidemia with DBP. CONCLUSION: 1. diastolic hypertension and low protidemia are the two most important factors predicting progression of renal failure; 2. a predictive synergy was furthermore pointed out between on one hand low protidemia and diastolic hypertension and on the other hand proteinuria and cholesterol; 3. on the contrary, anemia attenuates progression linked to low protidemia, diastolic hypertension, proteinuria and high cholesterol.

Acidosis↗
PubMed1999

Risk factors of renal failure progression two years prior to dialysis.

AIM: The respective contribution of sex, type of nephropathy, degree of proteinuria, blood pressure, protein and sodium daily intakes, blood lipid profile, protidemia, hemoglobinemia, acidosis and CaPO4 product on the rate of renal failure progression is debated. PATIENTS AND METHODS: The link between these parameters and the decrease of creatinine clearance, deltaCcr (according to Cockroft) was assessed in uni- and multivariate analysis in a population of 49 patients (26 women; age 60+/-15 years, weight 79+/-15 kg) selected out of 173 presently treated hemodialysis patients on the basis of availability of a quarterly follow-up for 2 years before starting dialysis. The patients were advised a moderate protein and salt restriction which could be retrospectively assessed (on urinary excretion of urea and sodium) at, respectively, 0.82 g/kg/day and 6.5 g/day. RESULTS: The 2-year deltaCcr was 14+/-14 ml/min. It was not different in men and women. This decrease in Ccr was neither significantly different in gomerular disease (17+/-8, n = 14), diabetic nephropathy (12+/-6, n = 7), nephroangiosclerosis (15+/-8, n = 5), interstitial nephritis (12+/-10, n = 14), and PKD (11 +/-12, n = 9). Patients with antihypertensive drugs (n = 42) had a faster progression than those without drugs (n = 7): deltaCcr = 15+/-14 vs 7+/-7 ml/min (p < 0.05) in spite of comparable blood pressure but with higher proteinuria. Linear regression of deltaCcr with the initial and 2-year averaged values of the quantitative parameters showed a significant positive link for both values with cholesterol, hemoglobine and proteinuria and a negative one with protidemia. A positive link was observed with the initial value of bicarbonate and the 2-year mean of diastolic and mean blood pressures. No link at all was observed with urea and Na excretion, CaPO4 product and triglycerides. Multiple regression disclosed a significant link only for protidemia (negative with both initial and 2-year averaged value), diastolic BP (only for the 2-year averaged value and hemoglobinemia (for the initial value). When the patients were classified according to a threshold value of their protidemia, DBP, hemoglobinemia, and cholesterolemia those with the combination of 2 risk factors of progression (protidemia > or = 66 g/l, DBP > or = 90 mmHg, hemoglobinemia > 11 g/dl, proteinuria > or = 3 g/d, CT > 5 mmol/l) had a significantly greater decrease of Ccr than those with the 3 other combinations at the exception of the association of low protidemia with DBP. CONCLUSION: Diastolic hypertension and low protidemia are the 2 most important factors predicting progression of renal failure. A predictive synergy was furthermore pointed out between low protidemia or diastolic hypertension with proteinuria and cholesterol. On the contrary anemia attenuates progression linked to low protidemia, diastolic hypertension, proteinuria and high cholesterol.

Anemia↗
PubMed1998

[Long-term stability of bone mineral density in patients with renal transplant treated with cyclosporine and low doses of corticoids. Protective role of cyclosporine?].

OBJECTIVES: Cyclosporine has been thought to have a deleterious effect on bone in transplant recipients because of high turnover osteopenia observed in humans after transplantation. However, varying confounding factors such as renal and parathyroid function, cumulative steroid doses and previous exposure to aluminium, also play a role and hinder interpretation of the cyclosporine effect on bone mineral density (BMD). PATIENTS AND METHODS: A 2-year prospective study was conducted to measure BMD starting 3 months after transplantation and bone remodeling markers from the first post-transplantation day in 52 kidney recipients with no prior exposure to aluminum. None of the patients experienced rejection and at 3 months all had good stable renal function (serum creatinine 137 mumol/l) and mildly elevated parathyroid hormone levels (1.5 times the upper limit of normal). All patients were given the same low dose steroid treatment (10 mg/day) and at 6 months cyclosporine was decreased from 7 to 4.8 mg/kg/day. RESULTS: BMD measured by double energy X-ray absorptiometry, (DEXA) and expressed in Z score, was moderately decreased at 3 months for the vertebrae (-1.40), the femoral neck (-1.34) and the ultradistal radius (-0.95) which have predominantly cancellous bone and was significantly less decreased (p < 0.05) for the lower third of the radius (-0.6) which is mainly cortical bone. BMD measurements were comparable at 6, 12 and 24 months. When measured by axial computerized tomography (ACT) BMD of the vertebrae showed a non-significant increase of Z score from -1.37 to -1.19 at 2 years. Bone remodeling markers was observed up to month 6 (from month 3 for osteocalcine and from month 1 for total and bone alkaline phosphatase and urinary pyridinoline), then returned to baseline levels at 2 years in parallel with decreased cyclosporine dosage. The increase of vertebral BMD measured by ACT at 1 year was correlated both to cyclosporine dose at 1 year and to bone alkaline phosphatase at 6 months. CONCLUSION: Our data confirm the presence of moderate osteopenia 3 months after transplantation, predominantly in trabecular bone, logically linked to the initial high doses of corticosteroids. The long-term stability of BMD measured by DEXA and the correlation of vertebral BMD increase measured by ACT with cyclosporine dose and bone alkaline phosphate suggest that cyclosporine had a beneficial immunosuppressor effect by stimulating bone remodeling and thus counterbalancing the suppressive effect of corticosteroids.

Adrenal Cortex Hormones↗
PubMed1998

Renal osteodystrophy in dialysis patients: diagnosis and treatment.

This article reviews the clinical, biological, radiological, and pathological procedures and their respective indications for the practical diagnosis of the following various histological patterns of renal osteodystrophy: osteitis fibrosa due to parathyroid hormone (PTH) hypersecretion: osteomalacia or rickets due to native vitamin D deficiency and/or aluminum overload; and adynamic bone disease (ABD) due to aluminum overload and/or PTH secretion oversuppression. Our advice regarding bone biopsy is to restrict it to patients with symptoms and hypercalcemia, especially those who have been previously exposed to aluminum. In other cases, we propose relying merely on the determination of the plasma concentrations of calcium, protide, phosphate, bicarbonate, intact PTH, aluminum, 25(OH)D3, and alkaline phosphatase (total and bony if hepatic disease is associated) to choose the appropriate treatment. Because of the danger of the desferrioxamine treatment necessary to chelate and remove aluminum, the suspicion of aluminic bone disease (osteomalacia or ABD) will always be confirmed by a bone biopsy. In the case of nonaluminic osteomalacia, correction of the vitamin D deficiency by native vitamin D or 25(OH)D3, and of the calcium deficiency and acidosis by alkaline salts of calcium and if necessary sodium bicarbonate are sufficient to cure the disease. In the case of nonaluminic ABD, the stimulation of PTH secretion by the discontinuation of 1alpha hydroxylated vitamin D and the induction of a negative calcium balance during dialysis by decreasing the calcium concentration in the dialysate will allow an increase of the CaCO3 dose to correct for hyperphosphatemia without inducing hypercalcemia. For hyperparathyroidism, i.e., plasma intact PTH levels greater than two- or four-fold the upper limit of normal levels (according to the absence or presence of previous aluminum exposure), the treatment will consist in increasing the CaCO3 dose to correct for hyperphosphatemia together with a decrease of the calcium concentration in the dialysate if the dose of CaCO3 is so high that it induces hypercalcemia. When the hyperphosphatemia has been corrected and there is still a low or normal corrected plasma calcium level, 1alpha(OH)D3 in an oral bolus 2 or 3 times a week should be given at the minimal dose of 1 microg. When the PTH level stays above 400 pg while hypercalcemia occurs and hyperphosphatemia persists, surgical subtotal parathyroidectomy is recommended or the injection of calcitriol into the big nodular hyperplastic parathyroid glands under sonography control in high surgical risk patients. Special recommendations are given for children.

Adult↗
PubMed1997

[Thrombotic thrombocytopenic purpura and hemolytic-uremic syndrome in adults. Apropos of 27 cases].

UNLABELLED: We report a series of 27 patients included on the basis of either thrombotic microangiopathy (TMA) at renal histology (13 cases) or, in the absence of histology, non-immunological hemolytic anemia with schizocytes and thrombopenia (14 cas). The etiopathogenic treatment consisted in the administration of antiagregating agents (in all patients except 3 of group I because of the severity of thrombopenic), corticosteroids (1 case), intravenous immunoglobulins (2 cases) fresh frozen plasma (FFP) without plasma exchange (PE) in 7 cases and PE with FFP in 13 patients. According to the 6 months outcome, 4 groups were considered I: death due to neurological damage; II: chronic hemodialysis; III: partial renal recovery; IV: complete renal recovery. COMMENTS AND CONCLUSIONS: a/Patients with neurological complications have poor prognosis in spite of minor renal involvement and use of PE whose indication is validated in these cases. b/When renal involvement predominates, accelerated hypertension is linked to arteriolar or mixte type of TMA, exposes to an increased risk of hemorrhagic complications of the renal biopsy (4 out fo 5) which questions the usefulness of such biopsy (group II). c/TMA may precede cancer. It has per se a favorable outcome even when metastases are already present, warranting aggressive treatment.

Adolescent↗
PubMed1995

1-alpha-Hydroxyvitamin D3 derivatives in the treatment of renal bone diseases: justification and optimal modalities of administration.

The use of 1 alpha-hydroxyvitamin D3 [1 alpha(OH)D3] derivatives in a uremic patient is justified only in the treatment of hyperparathyroidism (i.e. when plasma intact parathyroid hormone - PTH - levels are above five or three times the upper limit of normal according to whether the patient is on continuous ambulatory peritoneal dialysis or on hemodialysis and between 0.5-1.5, 1-2 and 2-3 times the upper limit of normal for a creatinine clearance of, respectively, 30, between 30 and 10, or below 10 ml/min/1.73 m2). The following prerequisites have however to be satisfied: (1) a good vitamin D3 repletion should be secured by plasma 25(OH(D) levels of 20-30 ng/ml (if necessary by administration of native vitamin D or 25(OH)D3), and (2) phosphate retention (which is aggravated by the increased phosphate intestinal absorption induced by the 1 alpha (OH)D derivatives) and the consequent possible hyperphosphatemia should be prevented or corrected by the oral administration of alkaline salts of calcium given before the meals as phosphate binders without inducing hypercalcemia. These prerequisites explain the narrow therapeutical margin of 1 alpha (OH)D3 derivatives in uremic patients before dialysis (more so in the adult than in the child) and the possible broadening of this margin in the patients on dialysis by the use of low dialysate calcium concentrations (1.25-1.00 mmol/l) in order to prevent hypercalcemia by inducing a negative perdialytic calcium balance. Once hyperphosphatemia is prevented by oral calcium, 1 alpha (OH)D3 derivatives have the advantage to suppress the transcription of the prepro PTH gene by a mechanism independent of an increase in plasma calcium. Controlled randomized trials have not confirmed the claimed advantage in efficacy and safety of the parenteral versus the oral route nor of the intermittent versus the daily mode of their administration. The advantages of using the so called 'nonhypercalcemic hyperphosphatemic' vitamin D3 derivatives in combination with oral calcium over 1 alpha(OH)D3 derivatives in the treatment of uremic hyperparathyroidism are still waiting for clinical demonstration. Vitamin D derivatives have no place in the treatment of aluminic bone diseases which necessitate long term deferoxamine treatment and prevention of aluminum exposure by the dialysate and the phosphate binders. They are not indicated in the treatment of 'idiopathic' adynamic bone disease which is due to uremia per se combined with an excessive PTH suppression for the degree of renal failure. This low bone turnover pattern is associated with an increased risk of hypercalcemia and hyperphosphatemia and necessitates only a stimulation of PTH secretion by inducing a negative calcium balance with a lower dialysate calcium concentration or simply by discontinuing the oral calcium supplement in the uremic patient not yet dialyzed. In rare cases this pattern is due to a granulomatosis and is corrected by prednisone.

Adult↗
PubMed1995

[Vitamin D treatment and renal osteodystrophy: indications and modalities].

1. 1 alpha (OH) vitamin D3 derivatives have an inconstant long term inhibitory effect on PTH secretion. As a matter of fact they act by three mechanisms, one of these being antagonistic: 1) a direct inhibitory action on the prepro-PTH gene; 2) an indirect inhibitory action by increasing plasma calcium; 3) an indirect stimulatory action by increasing plasma phosphate. These two latter phenomena are due to the stimulation of the intestinal absorption of these ions as well as to an intrinsic osteolytic action which may override the inhibition of the bone release of these ions in relation with the decrease of the PTH plasma levels. 2. The use of 1 alpha (OH)D3 derivatives in patients on chronic dialysis is justified in about 30% of the patients on dialysis when in spite of native vitamin D repletion and adequate predialysis control of plasma calcium (2.5 +/- 2 mmol/l) and of plasma phosphate (1.4 - 1.7 mmol/l), the PTH plasma levels are 3 or 5 fold the upper limit of normal whether the patient is on hemodialysis or on CAPD. When hyperphosphatemia is > 1.7 mmol/l it is first necessary to correct it by the use of higher doses of alkaline calcium salts given with the meals as phosphate binder together with a negative perdialytic calcium balance induced by a lower dialysate calcium in order to avoid hypercalcemia. Control of hyperphosphatemia is indeed a necessary prerequisite for the long term PTH suppressive efficacy of 1 alpha OH vitamin D derivatives. 3. The use of 1 alpha(OH)D3 derivatives in the treatment of the predialysis uremic patients is even more limited because there is no additional mean to decrease the risk of hypercalcemia when oral calcium is used as phosphate binder because of the danger of aluminum and magnesium phosphate binders. Fortunately in the adult, oral calcium used as phosphate binder in association with phosphate restriction and correction of possible vitamin D depletion and acidosis is usually efficace to control hyperparathyroïdism without 1 alpha OH vitamin D3. This is not the case in the child to whom protein and phosphate restriction should not be prescribed because of its incompatibility with the Recommended Diet Allowance. Fortunately the high remodeling rate of his growing bones, decreases the risk of hypercalcemia due to the combination of CaCO3 and 1 alpha OH vitamin D3.

Chronic Kidney Disease-Mineral and Bone Disorder↗
PubMed1994

Hypertension and progression of renal insufficiency.

Besides defining the appropriate doses of frusemide in uraemic patients, A. Heidland's contribution to the treatment of hypertension in chronic renal failure consisted in the following demonstrations: (1) In patients on chronic haemodialysis, calcium antagonists have a beneficial effect on their glucose intolerance and decreased plasma levels of 25OH vitamin D while their effect on blood lipids is neutral. (2) In 5/6 nephrectomized rats, captopril, verapamil, and metoprolol have the same protective effect on their GFR and tubular secretion of protons, at equal blood-pressure-lowering effect. (3) In rats with streptozotocin-induced diabetes, atrial natriuretic peptide does not play a role in their hyperfiltration. (4) Severe retinopathy is observed in patients with uraemic nephropathies at a much smaller elevation of their blood pressure than in patients with essential hypertension. This article reviews the following points: (1) The role of hypertension in the loss of renal function is convincingly demonstrated only in a few experimental models, and in man only in malignant hypertension and diabetic nephropathy but not in essential hypertension nor in non-diabetic nephropathy. However, preliminary results suggests that antihypertensive treatment may retard the progression of renal disease in normotensive patients (DBP <90 mmHg) with either microalbuminuric diabetes and normal renal function or non-diabetic uraemic nephropathy. (2) Only the ACE inhibitors have been proved to have a specific renal protective effect, independent of their diurnal blood-pressure-lowering effect, both in diabetic nephropathy and in non-diabetic uraemic nephropathy.

Angiotensin-Converting Enzyme Inhibitors↗