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Biomedical subjects

M Broyer

Publications and source records attributed to M Broyer.

At least 127 records · Page 7Linked to original sources

Collagen type III glomerulopathy: a new type of hereditary nephropathy.

A new type of hereditary glomerulopathy was observed in ten children presenting with early and progressive glomerular symptoms, often associated with hypertension. Light microscopy showed a diffuse increase in the mesangial matrix and generalized widening of the capillary walls. Electron-microscopic examination of renal tissue, after phosphotungstic acid treatment, revealed the presence of fibrillar collagen within the mesangial matrix and the subendothelial aspect of the glomerular basement membrane, adjacent to normal lamina densa. Immunohistochemical studies identified the fibrillar collagen not usually present within the glomerular extracellular matrix as type III collagen. Clinical and family studies ruled out the diagnosis of nail-patella syndrome, an autosomal dominant disorder with typical extrarenal symptoms, which is also characterized by the presence of fibrillar collagen within the glomerular basement membranes. The poor renal outcome, the possible extrarenal haematological and pulmonary involvement and the transmission as an autosomal recessive trait strongly suggest that collagen type III glomerulopathy is a new type of hereditary disease. From the high incidence of superimposed haemolytic uraemic syndrome in patients or their siblings, it may be hypothesized that collagen type III glomerulopathy is the underlying defect in some of the familial cases of haemolytic uraemic syndromes.

Adolescent↗

Non-immunological risk factors in paediatric renal transplantation.

In paediatric renal transplantation, non-immunological risk factors account for about one-third of graft losses. Recurrence of original disease is observed mainly in primary hyperoxaluria and glomerulopathies such as steroid-resistant nephrotic syndrome and membranoproliferative glomerulonephritis. In both glomerulopathies, 20% of grafts are lost from recurrence. Vascular thrombosis is, in most series, the second cause of graft loss in children, particularly in young recipients or with young donors (under 5 years of age). Non-compliance with treatment is a common non-immunological factor in adolescent recipients, which may trigger a severe rejection process resulting in graft loss. The role of factors related to graft preservation and intra- and post-operative management (ischaemia time, delayed graft function) or to cytomegalovirus infection is less obvious in our series. Prevention of vascular thrombosis and of non-compliance is most important in order to improve the results of paediatric renal transplantation.

Adolescent↗

A gene for familial juvenile nephronophthisis (recessive medullary cystic kidney disease) maps to chromosome 2p.

Familial juvenile nephronophthisis (NPH) is a chronic autosomal recessive kidney disease responsible for 15% of end stage renal failure in children. NPH is frequently (16% of cases) associated with Leber amaurosis (termed Senior-Løken syndrome, SLS). Linkage analyses, performed in 22 multiplex NPH families (18 without and 4 with ocular abnormalities), have localized the gene to a region between D2S48 and D2S51 on chromosome 2p. This was confirmed using adjacent microsatellite markers, one of which (AFM220ze3 at the D2S160 locus) gave a lod score of 4.78 at theta = 0.05 in the 18 families with isolated NPH, whereas the same marker excluded linkage with SLS. These results demonstrate linkage of the purely renal form of NPH to chromosome 2p, and suggest that there may be genetic heterogeneity between NPH and SLS.

Base Sequence↗

[Effectiveness of and tolerance to human recombinant erythropoietin in the treatment of kidney failure anemia in children undergoing continuous peritoneal dialysis. Multicenter study].

Eight young children with renal failure, undergoing continuous peritoneal dialysis (CDP) and presenting an anemia (hemoglobin level [Hb] 57 to 89 g/l) were treated by subcutaneous recombinant human erythropoietin (rHu EPO) twice weekly. The initial dose of 75 U/kg was adjusted to induce progressive increase of Hb with a target level of 100-120 g/l. Treatment duration was 24 weeks in five of these children and 10 to 13 weeks in the three others. In seven cases out of eight, anemia was corrected. The target Hb level was reached in 3 to 21 weeks with rHu EPO doses of 150 to 300 U/kg/w (mean: 200 U/kg/w) for four children without recent transfusion; then the median maintenance dose was 135 U/kg/w (range: 50-300 U/kg/w). In only one patient, Hb never reached a level higher than 77 g/l despite weekly dose of 350 U/kg, a reticulocytosis of 5.6%, rHu EPO treatment lasting up to 24 weeks and the absence of iron deficiency. In any case, no transfusion was necessary after the first day of rHu EPO treatment. In three patients, the increase of a preexisting hypertension required the adaptation of antihypertensive treatments. One patient presented a marked thrombocytosis. In conclusion, twice-a-week subcutaneous injections of 75 to 150 U/kg of rHu EPO appear to be well tolerated and effective in the treatment of anemia of CPD children.

Anemia↗

Platelet serotonin content and free and total plasma tryptophan in healthy volunteers during 24 hours.

The determination of platelet serotonin (5-HT) and plasma tryptophan concentrations is useful in the diagnosis, investigation of etiologies, and treatment of psychiatric disorders. To determine the usual circadian variations in platelet 5-HT and free and total tryptophan concentrations, we measured these variables during 24 h at 1-h intervals and every 30 min from 2000 to 0800 in seven clinically healthy young men with an HPLC method. No common circadian rhythm for platelet serotonin concentrations was observed in our subjects; however, there was a distinct rhythm for both free and total plasma tryptophan: Concentrations were maximal in the afternoon and minimal during the night.

Adult↗

Clinical significance of allograft glomerulopathy.

During the period from January 1973 to December 1990, 774 renal transplantations in 698 children were performed in our renal unit. A total of 540 grafts were examined both by light and immunofluorescence microscopy at least once. Recurrent glomerulonephritis was diagnosed in 62 grafts, de novo glomerulonephritis in 68 and allograft glomerulopathy in 38 (7%). The term allograft glomerulopathy (AGP) refers to the very specific pattern of glomerular involvement unique to renal allografts and characterized by: (1) widespread reduplication of the glomerular basement membrane due to a widening of the subendothelial space associated with (2) moderate increase in mesangial matrix and (3) interposition of mesangial matrix and cells. AGP is a glomerular manifestation of chronic rejection and is almost always associated with obliterative vascular changes. In our experience it is present in 25% of long-standing grafts (more than 10 years), but may develop early in the post-transplantation period (5 cases within the first year). In 13 of 33 patients in whom early biopsies were available, a different pattern characterized by a hypercellularity and the presence of monocytes-macrophages in the mesangial areas was observed. We suggest that this hypercellular pattern might be the early stage of the disease and could be called "acute allograft glomerulopathy" as opposed to the pattern characterized by reduplication of the glomerular basement membrane which deserves the name of "chronic allograft glomerulopathy." The exact relationship between these two patterns remains to be determined. Clinicopathologic correlations showed that chronic AGP is often associated with marked proteinuria. However, in our series proteinuria was absent or minimal in 25% of the cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Graft Rejection↗

A specific glomerular lesion of the graft: allograft glomerulopathy.

During the period from January 1973 to December 1970, 774 renal transplantations in 698 children have been performed in our Renal Unit. A total of 540 grafts have been examined both by light and immunofluorescence microscopy at least once. Recurrent glomerulonephritis was diagnosed in 62 grafts, de novo glomerulonephritis in 68 and allograft glomerulopathy (AGP) in 38. AGP was defined as a lesion affecting all glomeruli and characterized by widespread reduplication of the GBM with widening of the subendothelial space and interposition of mesangial matrix and without significant deposits by immunofluorescence. The aim of the current study is to describe the natural history of AGP and to delinate its clinical significance. At time of biopsy, an increase in serum creatinine was present in 30 patients associated with a proteinuria > or = 1 g/day in 21. During the post-transplantation course, proteinuria was present in 29 patients and associated with a nephrotic syndrome in 10 of them. With a mean follow-up of eight years seven months, two patients died, 23 lost their grafts and 13 have a functioning graft. The lesions of AGP recurred in three of the nine children who received a second graft. Thirteen of the 33 patients in whom earlier biopsies were performed showed a different pattern of involvement characterized by a prominent swelling of active endothelial and mesangial cells and a hypercellularity related to the presence of mononuclear cells both in the lumens and in the mesangial areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

[Renal transplantation in children under five years of age. Experience at the Hopital des Enfants-Malades].

From 1976 through 1991, 50 renal transplants (with 7 kidneys from living related donors and 43 cadaver kidneys) were performed in 47 children under five years of age (range 11 to 59 months) at the Enfants-Malades Hospital, Paris, France. Donor age ranged from 3 months to 53 years. Six of the seven kidneys from living related donors are currently functioning after a follow-up of 6 months to 8 years, whereas actuarial survival of cadaver kidneys was 70% at one year and 66% at five years. The main cause of graft loss was vascular thrombosis (40% of lost kidneys). In the most recent years of the study period, graft survival was substantially improved by routine prophylactic anticoagulant therapy with low-molecular weight heparin: one-year graft survival rate was 83% in the 23 children grafted between 1989 and 1991. Posttransplantation growth was closely related to quality of graft function: among the 29 children with sufficiently long follow-up the 19 patients with normal renal function exhibited normal or catch-up growth, whereas the ten patients with chronic renal failure or recent rejection had poor growth. Complications were uncommon with the exception of hypertension. Mortality rate was 12%, i.e., only slightly higher than in older pediatric kidney recipients. Achievement at school was normal in most cases (with a lag in only five patients). Provided effective therapy is given to prevent the main adverse outcome (i.e., vascular thrombosis), renal transplantation does not involve excessive risks even in infants as young as one year of age.

Actuarial Analysis↗

[Sugar diabetes after renal transplantation in children].

Posttransplant diabetes mellitus is ascribed to the use of corticosteroids. Because use of cyclosporine has been associated with increased rates of posttransplant diabetes mellitus, risk factors for this condition have been studied in adults and found to include older age, excessive body weight, and a family history for non-insulin-dependent diabetes mellitus. Only about 1% of children develop diabetes mellitus after transplant surgery. A study of pediatric transplant recipients with diabetes mellitus and of pediatric renal transplant recipients suggested that posttransplant diabetes mellitus may be more common in children with risk factors and may reveal types of diabetes which are infrequent in childhood, e.g., non-insulin-dependent diabetes mellitus which would have gone undiagnosed until adulthood in the absence of corticosteroid therapy. In contrast, corticosteroids apparently had little influence on glucose tolerance in subjects free of risk factors. The effect of corticosteroids seemed to be somewhat less marked than that of renal function impairment.

Adolescent↗

[Antenatal form of Bartter's syndrome].

Six cases of tubular disorder of antenatal onset responsible for biological manifestations characteristic of Bartter syndrome and severe hypercalciuria are reported. In all six cases, severe hydramnios occurred during pregnancy between the 26th and 28th week after the last menstrual period. All six patients were born prematurely; gestational age ranged from 20 to 35 weeks. Major polyuria with dehydration occurred immediately after birth. The amounts of water and sodium needed to compensate urinary losses ranged from 280 to 370 ml/kg/day and 25 to 43 mmol/kg/d, respectively, during the first two postnatal months. Decreased serum potassium levels and increased plasma levels of renin and aldosterone were seen in all six patients. Increased urinary excretion of calcium was evidenced during the first postnatal week in three cases. Urinary calcium excretion in the six patients ranged from 15 to 30 mg/kg/d. Nephrocalcinosis developed in all six patients and two patients developed urinary lithiasis. One patient died at one month of age from necrotizing enteropathy. The five remaining patients gradually developed severe growth failure with measurements between 4 and 5.5 SDs below the mean. These five patients had evidence of hyperparathyroidism including increased serum levels of parathyroid hormone (5/5), increased serum alkaline phosphatase activity (4/5), and roentgenographic bone changes (1/5). Ionized calcium assays performed in three of the five patients disclosed low values (range 1.25-1.47 mmol/l; mean = 1.35; normal values = 1.42-1.62), although total serum calcium levels were normal or high (range 2.16-2.98 mmol/l; mean 2.61; normal values = 2.45-2.65) probably as a result of chronic dehydration.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗