Monomeric and dimeric beta 2-microglobulin may be extracted from amyloid deposits in vitro.

Background: There is a controversy as to whether beta 2-microglobulin (beta 2M amyloid deposits may be degraded resulting in regression and cure of amyloidosis. We have recently reported a long-term clinical study involving transplanted patients suggesting that there is no resorption of amyloid deposits in vivo, even after correction of the primary cause of amyloidosis. To progress in the study of the solubility of amyloid fibrils we performed an in vitro study with the intent to remove protein constituents from amyloid fibrils and amyloid deposits.

Diffuse pulmonary calcinosis without calcium metabolism abnormalities in a renal transplant recipient.

Eighteen years after an uneventful renal transplantation, the chest radiograph of an asymptomatic 50 year old man showed diffuse bilateral infiltrations, predominately at the right apex. Computed tomography (CT) scan demonstrated a diffuse alveolar pattern, the alveoli being filled with a very dense material, with some tracheal calcifications. Bronchoalveolar lavage fluid analysis was normal, but bronchial and transbronchial biopsies revealed calcium deposits in the bronchial mucosa and in the alveolar septa.

Alpha 2-macroglobulin protects some of the protein constituents of dialysis-associated amyloidosis from protease degradation.

A crucial point to know in the prevention and treatment of beta 2-microglobulin (beta 2-m) amyloidosis is the putative resorption of amyloid fibrils in vivo. Although still controversial, long term clinical studies suggest that there is no resorption of amyloid fibrils in vivo, even after the suppression of the primary cause of amyloidosis. Two in vitro studies on murine and human AA amyloidosis as well as Alzheimer's disease suggest that protein constituents of amyloid fibrils may be resorbed.

Molecular and cellular events implicated in local tolerance to kidney allografts in miniature swine.

Long-term tolerance to class I-mismatched renal allografts can be induced in miniature swine by treatment with a short course of cyclosporine (CsA). Kidney recipients treated with CsA and untreated control kidney recipients both demonstrated infiltration of the transplanted kidney by mononuclear cells, which reached a maximum between postoperative days 8 and 11. Recipients that did not receive the tolerizing regimen rejected their grafts between postoperative days 8 and 12 in this model.

[Secondary hyperparathyroidism and multiple vertebral brown tumors: cure after parathyroidectomy].

A 46 year old man was referred for severe left cruralgia and multiple vertebral cystic defects on CT-scan. He was treated by hemodialysis since 1987 for chronic renal failure secondary to focal and segmental glomerulosclerosis, diagnosed in 1960 on renal biopsy. Dialysis schedule consisted of 3 x 4 h/week with a polysulfone dialyser and 1.

Oral vitamin D or calcium carbonate in the prevention of renal bone disease?

It is well known that hyperparathyroidism begins early in renal failure and progresses, probably not linearly, throughout the natural course of renal diseases and dialysis therapy. Recent progress in basic medical science has improved our understanding of the mechanisms by which the classically known stimuli for parathyroid hormone synthesis and secretion may act, including hypocalcaemia, hyperphosphataemia and vitamin D3 metabolism disturbances. In the treatment of hyperparathyroidism, although some authors stress the benefit of treating one of these stimuli, it is probably more effective to combine the treatment of them all.

[Intraglomerular hypertension. Physiopathology and therapeutic implications].

It is now well-established in experimental models in rodents that increased glomerular pressure results in the development of focal and segmental glomerulosclerosis, proteinuria and progressive renal functional deterioration. In humans, direct measurement of glomerular capillary pressure is impossible. However, it is widely accepted that glomerular hypertension is present in different clinical situations, like diabetic nephropathy, chronic renal failure associated with glomerulonephritides, some forms of essential hypertension and cadaveric kidney transplantation.

[Lipoprotein glomerulopathy: a new French case with recurrence on the transplant].

Lipoprotein glomerulopathy is defined by the presence of lipidic deposits in the capillary lumen giving them a dialted and microaneurysmal aspect and the presence of quantitative and/or qualitative alterations of plasma apolipoprotein E. We describe here the long-term follow-up of a young female patient who presented with corticoresistant nephrotic syndrome in 1979 and progressed to chronic renal failure requiring dialysis in 1990. The three renal biopsies performed during the follow-up showed markedly enlarged capillary loops due to intra-luminal fibrinolipidic material deposition forming true intracapillary thrombi.

Renal transplantation relieves the symptoms but does not reverse beta 2-microglobulin amyloidosis.

Renal transplantation is considered to be the treatment of choice of dialysis-related beta 2-microglobulin amyloidosis (DRA), as it provides near-normal serum levels of beta 2-microglobulin and obviates the need for dialysis. However, the long-term outcome of DRA after transplantation has not been fully assessed, and its evolution after transplant failure has not been reported. This study examined 17 patients with histologically confirmed DRA who underwent kidney transplantation and had a dialysis-free follow-up period in excess of 1 yr.

Beta 2 microglobulin isoforms in healthy individuals and in amyloid deposits.

beta 2 microglobulin (beta 2m) is classically known to have isoforms with isoelectric points (pI) 5.7 and 5.3.

[Morbidity of percutaneous biopsy of kidney transplants (Vim-Silverman and Tru-cut needles)].

Objectives: To evaluate the morbidity of renal transplant biopsies performed after simple ultrasonographic identification of the transplants, using a Vim-Silverman or Tru-cut needle.

Methods: From January 1987 to April 1991, 360 renal transplant biopsies were performed after simple ultrasonographic identification of the transplants, using a Vim-Silverman (n = 204) or Tru-cut (n-156) needle. In 221 transplants, these biopsies were performed because of a rise of serum creatinine (n = 319) or proteinuria (n = 17) or were even performed systematically (n = 24).

An acetohydroxy acid synthase mutant reveals a single site involved in multiple herbicide resistance.

Acetohydroxy acid synthase (AHAS) is an essential enzyme for many organisms as it catalyzes the first step in the biosynthesis of the branched-chain amino acids valine, isoleucine, and leucine. The enzyme is under allosteric control by these amino acids. It is also inhibited by several classes of herbicides, such as the sulfonylureas, imidazolinones and triazolopyrimidines, that are believed to bind to a relic quinone-binding site.

L-O-Methylthreonine-Resistant Mutant of Arabidopsis Defective in Isoleucine Feedback Regulation.

Threonine dehydratase/deaminase (TD), the first enzyme in the isoleucine biosynthetic pathway, is feedback inhibited by isoleucine. By screening M2 populations of ethyl methane sulfonate-treated Arabidopsis thaliana Columbia wild-type seeds, we isolated five independent mutants that were resistant to L-O-methylthreonine, an isoleucine structural analog. Growth in the mutants was 50- to 600-fold more resistant to L-O-methylthreonine than in the wild type.

Serial renal transplant surgery: technical reflections concerning third transplants.

From 1972 to 1993, we carried out 803 consecutive renal transplants including 8 third transplants. Exclusively cadaveric, these third renal transplants were implanted by intraperitoneal approach in right iliac position, without previous homolateral transplantectomy in 5 cases. The arterial anastomoses were common (7) or external iliac and hypogastric (1), and the venous anastomoses external (1) and common iliac (3), or inferior vena cava (4).

A double mutant allele, csr1-4, of Arabidopsis thaliana encodes an acetolactate synthase with altered kinetics.

A comparison is made of the kinetic characteristics of acetolactate synthase (EC 4.1.3.