PubMed Health⌕ Search

Biomedical subjects

A Chagnac

Publications and source records attributed to A Chagnac.

At least 55 records · Page 3Linked to original sources
PubMed1993

Angiotensin-converting enzyme inhibition and anaemia in renal patients.

A 35-year-old renal transplant patient with stable renal function developed an unexplained anaemia. Appropriate investigations proved non-diagnostic. Only when enalapril therapy was stopped did the anaemia reverse and haemoglobin levels returned to pre-treatment levels. An association between angiotensin-converting enzyme inhibitors and anaemia in patients with renal failure is becoming more evident. A literature review of this problem and its possible pathogenesis in patients with renal failure is given.

Adult↗
PubMed1992

The effect of high-dose nifedipine on renal hemodynamics of cyclosporine-treated renal allograft recipients.

Cyclosporine has been shown to reduce renal perfusion and to decrease glomerular filtration rate. Experimental studies suggest that nifedipine might reverse this renal vasoconstrictive effect of cyclosporine. We studied renal hemodynamics of 5 cyclosporine-treated renal transplant recipients before and after 2 weeks of therapy with high-dose nifedipine (up to 120 mg/day). Pretreatment GFR and renal plasma flow (RPF) were decreased. Following administration of nifedipine, RPF increased by 18% (P less than 0.01), while GFR did not change. Filtration fraction decreased by 10.5% (P less than 0.01). Mean arterial pressure declined from 111 +/- 5 to 96 +/- 3 mmHg (P less than 0.01). Renal vascular resistance dropped by 25% (P less than 0.01). Calculated postglomerular plasma flow increased by 20.5% (P less than 0.01). Urinary albumin excretion rate was unaffected. Cyclosporine whole blood levels were unchanged. The increase in RPF and in postglomerular plasma flow suggests that high-dose nifedipine might lessen cyclosporine-induced glomerular and interstitial ischemia in renal allograft recipients.

Adult↗
PubMed1992

Filtration dynamics and natriuretic response to volume expansion in humans.

We used differential solute clearances and a theoretical analysis of glomerular ultrafiltration and dextran sieving to characterize the hemodynamic response of nine healthy humans to infusion of isoncotic, 5% albumin in saline or saline vehicle alone. During albumin infusion (10.2 +/- 0.2 ml.kg-1.30 min-1) plasma volume increased by 18%, but oncotic pressure rose by only 0.8 mmHg. Despite the hypervolemia, renal blood flow (RBF) declined by 140 ml/min and glomerular filtration rate (GFR) declined by 16 ml/min during the infusion. RBF increased progressively postinfusion, exceeding baseline by 135 ml/min after 4 h; GFR was restored to baseline. Although oncotic pressure declined by 2 mmHg, a similar transient decline in GFR (-13 ml/min) was associated also with infusion of saline vehicle alone (9.4 +/- 0.3 ml.kg-1.30 min-1), which increased plasma volume by 9%. Sieving coefficients of dextrans (radius 32-42 A) were lowered during and after either infusion, a phenomenon that we compute to reflect a reduction in glomerular pore size. Assuming that the transcapillary hydraulic pressure difference was not lowered, we calculate that there was a simultaneous depression of the ultrafiltration coefficient (Kf) during volume expansion with saline and possibly also to a lesser extent with albumin. The hypofiltration during either infusion delayed the onset of a natriuretic response until the filtered sodium load was restored to baseline in the postinfusion period. We propose that the net effect of changes in intracapillary pressures and Kf during volume expanding infusions is to transiently lower GFR, thereby preventing the human kidney from mounting an immediate natriuretic response to acute hypervolemia.

Adult↗
PubMed1992

Unusual renal deposit in mixed connective tissue disease.

We describe a patient with clinical signs of mixed connective tissue disease who developed nephrotic syndrome. The kidney biopsy revealed glomerular and vascular deposits that stained positive with Congo red and showed a green birefringence. The Congo red positivity became negative in sections treated with potassium permanganate. Peroxidase-antiperoxidase staining with anti-AA antibodies was strongly positive. Ultrastructurally, although the deposits were similar to amyloid, they were about twice the size of amyloid fibrils. To our knowledge, the deposition of an amyloidlike material that shows the histochemical and immunohistochemical features of amyloid AA but is lacking the distinctive ultrastructural characteristics of amyloid fibrils has not been described.

Amyloid↗
PubMed1991

Extent of glomerular injury in active and resolving lupus nephritis: a theoretical analysis.

Patients with diffuse, proliferative lupus nephritis (DPLN) were subjected to differential solute clearances (n = 22) and serial renal biopsy (n = 11) before and again after 6-12 mo of immunosuppressive therapy. Glomerular sieving of dextrans of graded size was analyzed with a heteroporous membrane model. This revealed active DPLN to be associated with 1) a reduction of overall pore density accompanied by a 53% depression of glomerular filtration rate (GFR), and 2) appearance of a subset of large, nondiscriminatory pores, which accounted for the observed nephrotic level of proteinuria. Morphometric analysis of biopsy tissue provided evidence of reduced filtration surface area due to global or segmental occlusion of capillary loops in glomerular tufts. Activity of DPLN resolved posttreatment. A computed increase in pore density was associated with a 24% increment in GFR; a marked reduction in the fraction of shuntlike pores was accompanied by a parallel reduction of proteinuria into a subnephrotic range. Repeat biopsy revealed diminished glomerular cellularity, fewer immune deposits, and an ensuing increase in the fraction of tuft area occupied by patent loops. Epithelial filtration slit frequency also increased. Neither functional nor structural recovery was complete, however. Residual pore density approximated only 23-35% of that in healthy controls, and corresponding shuntlike pores were threefold more prominent. We conclude that severe DPLN is only partially reversible by current modalities of treatment and that the ensuing residual injury is far more severe than suggested by conventional tests of renal function.

Adolescent↗
PubMed1991

Subclavian vein stenosis, permanent cardiac pacemakers and the haemodialysed patient.

Two cases of subclavian vein stenosis secondary to permanent cardiac pacemakers are presented. Both stenoses were asymptomatic until arteriovenous fistulae/grafts were constructed in order to initiate haemodialysis. One patient experienced severe oedema of the arm which necessitated surgical closure of the graft. A literature review into major venous stenosis and cardiac pacemakers reveals an asymptomatic, but evidently underestimated, problem. As more elderly patients will be accepted onto haemodialysis programmes, this above-mentioned problem may become more common. Therapeutic answers as to haemodialysis access are discussed in these patients with permanent pacemakers who need haemodialysis.

Aged↗
PubMed1991

Pneumococcal peritonitis complicating CAPD--was the indwelling intrauterine device to blame?

A 45-year-old woman on CAPD developed pneumococcal peritonitis. This is the second such case of Streptococcus pneumoniae peritonitis complicating CAPD. The role of an indwelling intrauterine device (IUD) in producing ascending infection into the peritoneum is discussed, especially in women with evidence of retrograde menstruation. A review of the literature concerning pneumococcal peritonitis associated with IUD is given. Possible contraception to women on CAPD is briefly mentioned.

Drug Therapy, Combination↗
PubMed1990

Unusual case of crescentic glomerulonephritis associated with malignant lymphoma. A case report and review of the literature.

Renal lesions in non-Hodgkin's lymphoma are rare. Furthermore, to the best of our knowledge, only 5 cases of crescentic glomerulonephritis associated with non-Hodgkin's lymphoma have been previously described. We report a case of crescentic glomerulonephritis and renal failure which preceded the diagnosis of non-Hodgkin's lymphoma. Following steroid therapy there was a resolution of these histological findings a year later.

Acute Kidney Injury↗
PubMed1990

Erythrocytosis associated with renal artery thrombosis in a patient with polycystic kidney disease on hemodialysis.

We report a case of erythrocytosis in a patient with end-stage renal failure on chronic hemodialysis. The patient with polycystic kidney disease had an average Hb level of 10 g/dl while on hemodialysis for 3 years. He developed erythrocytosis (Hb 17.6 g/dl) following a cadaveric renal transplantation. No signs suggesting polycythemia vera were found. Nonrenal causes of secondary erythrocytosis such as anoxia, hemoglobinopathies or tumors were excluded. Angiography showed renal artery occlusion of the native kidney. Serum erythropoietin level was 85 U/l (normal 52 +/- 31 U/l) as measured by 3H-thymidine uptake. It is suggested that ischemia caused by the renal artery thrombosis stimulated the erythropoietin production in the native polycystic kidney.

Anemia, Hypochromic↗
PubMed1989

Enalapril attenuates glomerular hyperfiltration following a meat meal.

It has been shown that the glomerular filtration rate increases after a meat meal. We examined in humans whether enalapril, which has been shown to decrease glomerular capillary pressure in rats with chronic renal failure, could attenuate the renal response to a meat meal. Twelve healthy volunteers were studied after an oral protein load, 1.5 g/kg body weight, as lean cooked beef meat, and on a separate day, after eating the same meal with prior oral intake of enalapril. On the control day, creatinine clearance increased from 114.3 +/- 4.7 before the meal to 137.1 +/- 4.7 ml/min/1.73 m2 after the meal (p less than 0.001). On the enalapril intake day, creatinine clearance increased from 113.7 +/- 5.6 before the meal to 128.3 +/- 5.8 ml/min/1.73 m2 after the meal (p less than 0.01). However, the mean increase in creatinine clearance was lower on the enalapril intake than on the control day (14.0 +/- 4.3 vs. 21.0 +/- 4.1%, p less than 0.05). Mean arterial pressure before the meal was lower on the enalapril intake day than on the control day (76.2 +/- 3.5 vs. 84.2 +/- 3.6, p less than 0.01). Likewise, postprandial mean arterial pressure was lower on the enalapril day compared with the control day (69.9 +/- 2.8 vs. 78.5 +/- 3.7, p less than 0.01). We conclude that enalapril blunts the hyperfiltration which follows a meat meal.

Adult↗
PubMed1989

Outcome of the acute glomerular injury in proliferative lupus nephritis.

Treatment with total lymphoid irradiation (TLI) and corticosteroids markedly reduced activity of systemic lupus erythematosis in 10 patients with diffuse proliferative lupus nephritis (DPLN) complicated by a nephrotic syndrome. Physiologic and morphometric techniques were used serially before, and 12 and 36 mo post-TLI to characterize the course of glomerular injury. Judged by a progressive reduction in the density of glomerular cells and immune deposits, glomerular inflammation subsided. A sustained reduction in the fractional clearance of albumin, IgG and uncharged dextrans of radius greater than 50 A, pointed to a parallel improvement in glomerular barrier size-selectivity. Corresponding changes in GFR were modest, however. A trend towards higher GFR at 12 mo was associated with a marked increase in the fraction of glomerular tuft area occupied by patent capillary loops as inflammatory changes receded. A late trend toward declining GFR beyond 12 mo was associated with progressive glomerulosclerosis, which affected 57% of all glomeruli globally by 36 mo post-TLI. Judged by a parallel increase in volume by 59%, remaining, patent glomeruli had undergone a process of adaptive enlargement. We propose that an increasing fraction of glomeruli continues to undergo progressive sclerosis after DPLN has become quiescent, and that the prevailing GFR depends on the extent to which hypertrophied remnant glomeruli can compensate for the ensuing loss of filtration surface area.

Acute Disease↗
PubMed1989

Effect of verapamil on bone resorption and formation in uremic rats.

It has been shown in vitro that verapamil inhibits parathyroid hormone-induced bone resorption. To determine the effect of verapamil administration on bone histology in rats with chronic renal failure, male Wistar rats were divided into three groups: subtotally nephrectomized (SNX), SNX treated with verapamil, 8 mg/kg/day p.o. (SNX-V) and control (C). Thirteen weeks later, the mandibular condyle bone was studied by histomorphometry. When compared to C rats, SNX rats had active bone disease, with increased resorption parameters (resorption surface, active resorption surface, osteoclast number) and accelerated mineral appositional rate. These parameters improved with verapamil administration. When compared to C rats, SNX-V rats had decreased osteoid seam width and mineral appositional rate. Serum parathyroid hormone was similarly elevated in both uremic groups. These data suggest that verapamil administration improves active bone disease in rats with chronic renal failure and decreases bone formation.

Animals↗
PubMed1988

Therapy with nifedipine in asthma: a randomized double-blind crossover trial.

A randomized double-blind crossover trial with nifedipine (10 mg orally four times a day for 2 weeks) was carried out in 11 asthmatic patients. The analysis of the differences between the periods of running-in, placebo and nifedipine administration showed a mild improvement in symptom scores during the nifedipine period (2.8 +/- 1.5, 2.8 +/- 1.8 and 2.1 +/- 1.6, respectively; P less than 0.05). Drug intake and peak expiratory flow rates remained unchanged. This suggests that the drug did not influence the baseline bronchial tone, but might have attenuated some superimposed exacerbations due to unavoidable exposure to cold, effort or allergens. We conclude that the benefit of orally administered nifedipine in low doses has little value in the treatment of asthma.

Adult↗