Search PubMed⌕ Search

Biomedical subjects

B Gauthier

Publications and source records attributed to B Gauthier.

At least 37 records · Page 2Linked to original sources
PubMed1996

Predicting daily maintenance dose of fluindione, an oral anticoagulant drug.

Due to large inter-individual variations, the dose of vitamin K antagonist required to target the desired hypocoagulability is hardly predictible for a given patient, and the time needed to reach therapeutic equilibrium may be excessively long. This work reports on a simple method for predicting the daily maintenance dose of fluindione after the third intake. In a first step, 37 patients were delivered 20 mg of fluindione once a day, at 6 p.m. for 3 consecutive days. On the morning of the 4th day an INR was performed. During the following days the dose was adjusted to target an INR between 2 and 3. There was a good correlation (r = 0.83, p < 0.001) between the INR performed on the morning of day 4 and the daily maintenance dose determined later by successive approximations. This allowed us to write a decisional algorithm to predict the effective maintenance dose of fluindione from the INR performed on day 4. The usefulness and the safety of this approach was tested in a second prospective study on 46 patients receiving fluindione according to the same initial scheme. The predicted dose was compared to the effective dose soon after having reached the equilibrium, then 30 and 90 days after. To within 5 mg (one quarter of a tablet), the predicted dose was the effective dose in 98%, 86% and 81% of the patients at the 3 times respectively. The mean time needed to reach the therapeutic equilibrium was reduced from 13 days in the first study to 6 days in the second study. No hemorrhagic complication occurred. Thus the strategy formerly developed to predict the daily maintenance dose of warfarin from the prothrombin time ratio or the thrombotest performed 3 days after starting the treatment may also be applied to fluindione and the INR measurement.

Administration, Oral↗
PubMed1994

Renal reperfusion injury: sequential changes in function and regional albumin extravasation.

We report on the renal function and regional extravasation of albumin-bound Evans blue dye (EB) in the kidneys of anesthetized dogs following 30 min occlusion of the left renal artery. Left kidney (LK) function was halted and no change in right kidney (RK) function was observed during ischemia. Clearances of para-amino-hippurate and inulin from the LK were significantly (P < 0.01) less than control after 10 min of reperfusion, 22.6 +/- 6.8 vs 90.1 +/- 7.8 and 9.0 +/- 2.9 vs 34.2 +/- 2.1 ml/min, respectively. Renal hemodynamic parameters never did fully recover in subsequent periods but filtration fraction was unchanged from control throughout the reperfusion period. Urine flow and sodium excretion from the LK was significantly (P < 0.01) less than control values after 10 min of reperfusion, 0.41 +/- 0.14 vs 0.80 +/- 0.08 ml/min and 60 +/- 21 vs 161 +/- 8 mu eq/min, respectively, but fully recovered in subsequent periods. Significant (P < 0.01) decrease from control values in the LK content of EB was observed in the inner medulla and papilla regions after 30 min of reperfusion, 586 +/- 60 vs 763 +/- 51 and 549 +/- 54 vs 741 +/- 52 micrograms/EB/g dry tissue, respectively. After 60 min of reperfusion in the LK, significant (P < 0.05) changes from control in EB content were evident exclusively in the outer medulla, increasing from 398 +/- 56 to 491 +/- 17 micrograms/EB/g dry tissue, respectively. A general edema in the LK, measured as an increase in the ratio of wet/dry tissue weight, became evident only after 60 min of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1994

Isolated proteinuria in children. Natural history and indications for renal biopsy.

The significance of isolated proteinuria in pediatric patients is uncertain. Therefore, we retrospectively studied all children evaluated for this urinary abnormality during the 6-year period from 1986 to 1992. Thirty-one patients (19 males), age 2 to 20 years, were identified as having isolated proteinuria that had persisted for a mean interval of 9.6 +/- 1.9 (SEM) months. The diagnosis was based upon the presence of a urine protein:creatinine ratio > 0.2 in an early-morning specimen. None of the patients had hematuria, edema, or azotemia. Seventeen children underwent a renal biopsy. There was no difference between the patients who were biopsied and those who were not with respect to age, magnitude of proteinuria, glomerular filtration rate (GFR), or serum albumin and cholesterol concentrations. The renal histopathology revealed focal segmental glomerulosclerosis (FSGS) (n = 8), membranous nephropathy (n = 1), postinfectious nephritis (n = 2), focal global glomerulosclerosis (FGGS) (n = 1), and normal kidney tissue (n = 5). Twelve of the patients who did not undergo a kidney biopsy and four of the five children with a normal renal biopsy were followed for at least 12 months; there was complete resolution of the proteinuria in 11 (69%) of these patients. The level of proteinuria did not predict the presence or absence of important kidney disease. However, if isolated proteinuria persists for more than 1 year, it is then unlikely to spontaneously remit and a renal biopsy is indicated to clarify the nature of any underlying glomerulopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Influence of long term oral anticoagulants upon prothrombin fragment 1 + 2, thrombin-antithrombin III complex and D-Dimer levels in patients affected by proximal deep vein thrombosis.

We have investigated the influence of long term oral anticoagulants (OAC) upon the plasma levels of prothrombin fragment 1 + 2 (F1 + 2), of thrombin-antithrombin III complexes (TAT) and of D-Dimer in 20 patients affected by a proximal deep vein thrombosis (DVT) diagnosed by ultrasonic duplex scanning. Patients (63 +/- 17 years, mean +/- SD) were sampled at the beginning of the OAC treatment (day 1), which was started 1 to 6 days after diagnosis confirmation and full heparinization, and then 8, 35 and 92 days after. The results were compared to those obtained in a blood donor population (39 +/- 10 years) and to an age-matched healthy population (63 +/- 19 years). The mean INR determined on days 8, 35 and 92 were almost identical (2.8 +/- 0.7, 2.9 +/- 0.9 and 2.8 +/- 0.6 respectively). In contrast, highly significant variations of the three markers were recorded during the observation period. Eight days after the beginning of OAC, increased levels of TAT complexes were associated with subnormal levels of F1 + 2 suggesting persistence of a hypercoagulable state. On the further sampling times, TAT complexes were in the normal range while F1 + 2 were far below the normal range. Between day 1 and day 92, the levels of D-Dimer continuously decreased reflecting a long-term fibrinolytic process. This study clearly indicates that high INR are not systematically associated with very low F1 + 2 levels, particularly in the acute phase of thrombosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Schönlein-Henoch nephritis and IgA nephropathy in children.

When Schönlein-Henoch nephritis presents with more than just microhematuria, only 72% of cases go on to complete recovery. Evidence of renal disease may reappear after apparent complete recovery. Schönlein-Henoch nephritis may be the single commonest form of crescentic glomerulonephritis, accounting for 30% of cases. Prednisone for 2 weeks may prevent Schönlein-Henoch nephritis in children who do not already have it when first seen. IgA nephropathy was found in 8% of children with isolated proteinuria and has been reported with human immunodeficiency virus infection. Heavy proteinuria at onset, focal sclerotic and tubulointerstitial changes, and crescents and capsular adhesions are poor prognostic indicators. The prognostic significance of hypertension and of the absence of gross hematuria remains uncertain. After a follow-up of at least 8 years, 53% of patients are clinically in remission. In a short-term double-blind, crossover trial, prednisone had no effect on IgA nephropathy. Recent advances do not yet lead to a unifying concept of the pathogenesis of Schönlein-Henoch nephritis or IgA nephropathy.

Child↗
PubMed1992

Hypercalciuria in children with renal glycosuria: evidence of dual renal tubular reabsorptive defects.

During the past 5 years, we have identified idiopathic hypercalciuria in five of seven patients referred for evaluation of renal glycosuria between 1985 and 1991. The children, all boys, ranged in age from 6 to 12 years. Endocrine function was normal, and none of the patients had hyperparathyroidism, hypercalcemia, renal tubular acidosis, or other secondary causes of hypercalciuria. The calcium/creatinine ratio in a fasting urine specimen was elevated in all five children who had hypercalciuria, with a mean value (+/- SD) of 0.34 +/- 0.06 (normal, < 0.2). In one child who had renal colic with spontaneous passage of gravel-like material, the idiopathic hypercalciuria persisted after 1 week on a diet containing 2000 mg of sodium and 300 mg of calcium. On the basis of studies that examined the site along the nephron responsible for hypercalciuria in rats with streptozocin-induced diabetes, we speculate that in children with renal glycosuria, there is defective reabsorption of glucose and calcium in the straight portion of the proximal tubule or in the collecting duct. It is likely that a similar mechanism accounts for the idiopathic hypercalciuria in children with diabetes mellitus.

Absorption↗
PubMed1992

Clinical, cognitive, and neurophysiological effects of alprazolam in children and adolescents with overanxious and avoidant disorders.

In a double-blind, placebo-controlled study, the efficacy and safety of alprazolam was investigated in childhood and adolescent anxiety disorders. Thirty patients (mean, 12.6 years) diagnosed with overanxious or avoidant disorders participated in the study. Evaluations included clinical, laboratory, cognitive, and qualitative EEG measurements. On a clinical global rating, there was no statistical difference between alprazolam and placebo. Relative to baseline EEG, acute alprazolam administration increased beta power in the right occipital lead, and chronic administration increased beta power in both leads. Alprazolam was well tolerated, and adverse effects were few, mild, and transient.

Adolescent↗
PubMed1991

Inadequacy of captopril challenge test for diagnosing renovascular hypertension in children and adolescents.

A captopril challenge test (CCT) for renovascular disease in adults was described recently. We used it in 20 consecutive, untreated hypertensive children and adolescents. All had a normal urinalysis and glomerular filtration rate and non-diagnostic renal sonograms or intravenous urograms. Plasma renin activity (PRA) was measured before and 1 h after administration of captopril (0.76 +/- 0.17 mg/kg). The CCT was positive in 10 patients. Renal arteriograms were performed in 7 patients with a positive CCT and in 2 with a negative CCT. Renovascular disease was found in 4 patients, 1 of whom had a negative CCT. The PRA response to captopril was the same in patients with true- and the false-positive tests. The predictive value of the positive test was 43%. In conclusion, we did not find the CCT, as described for adults, to be of value in children and adolescents.

Adolescent↗
PubMed1991

Renal transplantation in children: an American view from the bridge.

Performance of renal transplants in children frequently necessitates transfer of patients from the care of a local pediatric nephrologist to a regional, tertiary care center that is specially equipped to carry out organ transplantation. This shift in institutional affiliation can be the cause of some difficulties in treating these complicated patients including: (1) disparities in the expected outcome of the renal transplant procedure; (2) co-ordination and timely completion of the pre-operative evaluation; (3) proper handling of transfers of patients between medical centers and inter-physician communication; (4) psychosocial pressures encountered by parents when their children are under the care of two teams of physicians. It is recognized that the relationship between the referring pediatric nephrologist and the transplant physician is paradigmatic of the association that develops between a general practitioner and a specialist. With this in mind, we offer some tentative suggestions on how to improve the therapeutic alliance between referring pediatric nephrologists and transplant surgeons, in the hope that this will improve the care of all pediatric transplant recipients.

Attitude of Health Personnel↗
PubMed1991

IgA nephropathy in a child with human immunodeficiency virus type 1 infection.

Infection with the human immunodeficiency virus type 1 (HIV-1) can cause a spectrum of renal disease, termed acquired immunodeficiency syndrome (AIDS) nephropathy. The most common clinical manifestations of kidney involvement in HIV-1-infected patients are proteinuria and/or nephrotic syndrome, and the histopathological pattern usually reveals focal segmental glomerulosclerosis. We describe an 8-year-old child with AIDS who presented with recurrent gross hematuria. A kidney biopsy demonstrated IgA nephropathy. This unique case indicates that the range of kidney disease in HIV-infected children may be broader than originally thought, and that these patients warrant a complete evaluation of any renal abnormality.

Biopsy↗
PubMed1990

The renal functional and structural consequences of corticosteroid and angiotensin-converting enzyme inhibitor therapy in chronic puromycin aminonucleoside nephropathy.

Glomerular diseases are characterized by increased urinary protein excretion. Treatment of this abnormality frequently involves administration of corticosteroids and angiotensin-converting enzyme inhibitors. There has been much recent interest in the potential impact of these drugs on progressive renal dysfunction, since they have opposing effects on intraglomerular hemodynamics. Therefore, we investigated the effect of methylprednisolone or captopril treatment on animals with chronic puromycin aminonucleoside nephropathy. In rats given a single injection of puromycin aminonucleoside, 15 mg/100 g body weight, both methylprednisolone and captopril significantly reduced proteinuria at 6 months [83 +/- 14 untreated (n = 7), 34 +/- 6 with methylprednisolone (n = 8), and 6 +/- 1 mg/24 h with captopril (n = 5), P less than 0.001]. Segmental glomerulosclerosis occurred with equal frequency in the untreated (7.8 +/- 2.3%) and methylprednisolone-treated rats (5.0 +/- 1.11%), but was significantly reduced by the administration of captopril (1.0 +/- 0.5%, P less than 0.001). We conclude that in chronic puromycin aminonucleoside nephropathy, treatment with corticosteroids reduces proteinuria without increasing the incidence of segmental glomerulosclerosis. Therapy with an angiotensin-converting enzyme inhibitor substantially decreases proteinuria and lessens the severity of glomerular scarring.

Adrenal Cortex Hormones↗
PubMed1990

Hypocalcemia and hypercalcitoninemia in critically ill children.

To study Ca metabolism in critically ill children, we measured ionized Ca (Ca2+), parathyroid hormone (PTH), calcitonin, 25 hydroxycholecalciferol (25[OH] D3), 1-25 dihydroxycholecalciferol (1-25[OH]2D3, and gastrin levels in critically ill children and in healthy controls. Patients were considered hypocalcemic if Ca2+ was less than 1.1 mmol/L. Six (14%) of 45 patients were hypocalcemic. Five hypocalcemic patients were studied and were found to have higher calcitonin levels than normocalcemic patients and healthy controls and higher PTH levels than healthy controls. 25(OH)D3 and 1-25(OH)2D3 were not significantly different in the three groups of patients. Gastrin levels were low in critically ill patients, whether or not they were hypocalcemic. We conclude that hypocalcemia occurs frequently in critically ill children. It is associated with raised levels of calcitonin and PTH. The mechanism for the increase in calcitonin is unknown.

Acute Disease↗
PubMed1990

Kearns-Sayre syndrome presenting as renal tubular acidosis.

Renal tubular acidosis and tetany were the 1st manifestations of Kearns-Sayre syndrome in a 5-year-old child. Subsequently, he developed progressive external ophthalmoplegia, ptosis, retinopathy, heart block, and endocrinopathy. There was a 7.5-kb deletion of mitochondrial DNA documented in muscle, kidney, skin fibroblasts, and leukocytes, providing evidence for a multisystem mitochondrial cytopathy.

Acidosis, Renal Tubular↗
PubMed1990

Acute interstitial nephritis in adolescents and young adults.

We have reviewed our experience with acute interstitial nephritis (AIN) in pediatric patients over the 3-year period from 1985 to 1988. We encountered 7 new cases of AIN in this interval and it was seen in 7% of kidney biopsies performed during this time of study. The clinical presentation was very nonspecific and included fever (100%), gastrointestinal complaints (57%) and rash (28%). Laboratory findings on admission included elevated erythrocyte sedimentation rate (100%), anemia (70%), pyuria (57%) and abnormal renal ultrasound (86%). Associated systemic diseases were observed in 4 patients. AIN was severe enough to necessitate treatment with hemodialysis in 42% of the cases. Corticosteroid therapy was used in 6 patients with a favorable response in all but 1 case. While 6/7 patients manifested complete recovery, 1 adolescent who may have had pre-existing renal disease had persistent chronic renal failure (estimated GFR, 25 l/min/1.73 m2). We have concluded that: (1) AIN is a relatively common disease in pediatric practice; (2) it can be severe enough to necessitate dialysis therapy, and (3) AIN often occurs in children with systemic disorders that may be associated with immunologic disorders.

Adolescent↗