Search PubMed⌕ Search

Biomedical subjects

P Jablonski

Publications and source records attributed to P Jablonski.

At least 73 records · Page 4Linked to original sources

Glomerular epithelial cell lesions in rat renal isografts.

Visceral glomerular epithelial cell lesions--microvillus formation, loss of foot processes, osmiophilic inclusion droplets, balloon-like malformation of cell processes, degeneration, necrosis, and loss of cell processes from capillary basement membranes--are found in rat renal isografts 1 mth after transplantation. The lesions, which are most readily recognized in perfusion-fixed material, are essentially focal, affecting neither all glomeruli, nor all cells in any glomerulus, bear no relation to the degree of interstitial nephritis in the graft, and are associated with albuminuria and with focal capillary sclerosis in some glomeruli. They are not restricted to renal isografts but are found in aging rats, in different experimental models of glomerular disease and in clinical glomerular disorders, again in association with proteinuria and glomerulosclerosis. It is therefore proposed that glomerular epithelial cell damage increases capillary permeability and impairs maintenance of the integrity of the capillary wall, leading to proteinuria and focal glomerulosclerosis.

Animals↗

Rat pancreas preservation for transplantation.

This study has shown that phosphate-buffered sucrose is a suitable preserving solution for the cold storage of rat pancreata for 24 hours. Isotonic citrate does not appear to be as effective a preserving solution under these conditions. Preservation of endocrine function is evident, but preservation of exocrine function is effected by obstruction or occlusion of the ductocystostomy, which may occur some time after transplantation and may not be related to transplant conditions.

Amylases↗

Cyclosporine and the ischemic rat kidney.

The effects of cyclosporine (CsA) on renal function and morphology have been studied in the rat after unilateral nephrectomy and warm renal ischemia. There is evidence of an enhanced CsA nephrotoxic effect after unilateral nephrectomy alone and of an additive or synergistic effect of CsA and renal ischemia upon renal function and morphology. These enhanced effects are most evident after longer periods of ischemia (60 min) and with higher doses of CsA (25 mg/kg/day). The findings may be relevant to clinical practice and suggest that the nephrotoxic effects of CsA upon the donor kidney may be greatest when there is coincident renal damage from other causes.

Animals↗

Glomerular damage after kidney preservation.

Severe proteinuria occurs during isolated organ perfusion of kidneys removed from SD and DA rats and subjected to 24-hr cold preservation. In both strains increased glomerular permeability was associated with changes in glomerular visceral epithelial cells, particularly cytoplasmic edema and detachment of cells from capillary basement membranes. Foot processes were intact and staining for sialoglycoprotein was retained. The changes were compatible with survival of the isograft kidney after transplantation, but moderate proteinuria was found in some rats after one month. Protein loss in the urine during isolated organ perfusion is very much less in kidneys subjected to 4-hr cold preservation, and the glomerular epithelial cells are normal or show only minimal cytoplasmic edema on electron microscopy. The experiment shows that significant damage to glomeruli may occur during preservation prior to transplantation, and the model itself can be usefully exploited to determine the relation between increased glomerular permeability to albumin and the associated changes in the glomerular capillary wall.

Animals↗

The influence of the contralateral kidney upon recovery from unilateral warm renal ischemia.

Unilateral warm renal ischemia of 90 min duration was induced in rats and the contralateral normal kidney was removed either immediately or after 1, 2, 4 or 14 d. Contralateral nephrectomy at 2, 4, 14 d increased survival and modified the functional and morphological events of the recovery period. Optimal recovery was obtained by 4 d delay. When contralateral nephrectomy was delayed by 14 d, scarring of the ischemic kidney was more severe suggesting that regeneration of damaged nephrons was impaired when renal homeostasis was sustained by the contralateral kidney. Such biphasic and inverse effects of normal kidney tissue are likely to be important determinants of the natural history of severe unilateral renal damage.

Animals↗

Studies in renal preservation using a rat kidney transplant model: II. The effect of reflushing with citrate.

This study investigated the possible beneficial effects of reflushing renal grafts with isotonic citrate solution. Rat kidneys were initially flushed with isotonic citrate or with Hartmann's solutions at O C. After 2 hr, half the kidneys of each group were reflushed with isotonic citrate; 22 hr later, all kidneys were transplanted into rats of the same inbred strain. All animals receiving kidneys flushed with Hartmann's solution died, whereas reflushing such kidneys with isotonic citrate significantly ameliorated the deleterious effects of Hartmann's solution. All animals receiving citrate-flushed kidneys survived with relatively good renal function and morphology. However, reflushing itself is not a beneficial procedure and is only of value where an ineffective preserving solution has been used to flush the kidneys initially. There is evidence that some of the adverse effects of flushing develop in the renal medulla.

Animals↗

An experimental model for assessment of renal recovery from warm ischemia.

A study was made of the acute and chronic (15 days) functional and morphologic effects on the rat kidney of warm ischemia and contralateral nephrectomy, in order to define a suitable animal model for testing renal transplant preservation techniques when warm ischemia is a contributing factor. Spontaneous recovery from 30-min warm ischemia was complete, and the model was consequently unsuitable; the high mortality from 90 min was unacceptable. Warm ischemia of 60 minutes produced severe renal tubular necrosis, an acceptable mortality, residual morphologic damage, and impairment of isolated kidney perfusion parameters at 15 days. Renal function in vivo was normal in many of these animals, despite appreciable residual morphologic changes, and it is evident that functional data alone are not sufficient for assessment of preservation regimens.

Animals↗

Studies of renal preservation using a rat kidney transplant model. Evaluation of citrate flushing.

Rat kidneys were flushed with isotonic citrate solution, hypertonic citrate solution, or Collins's C2 solution, and were stored hypothermically for 24 hr before transplantation into another rat of the same inbred colony. The number of animals surviving for one month was greatest with isotonic-citrate-flushed kidneys (82%), and least with Collins's C2 solution (27%). Functional and morphological damage after transplantation was consistently greater in Collins's-flushed grafts, as compared with citrate-flushed grafts. Best results were attained with the isotonic-citrate flushed grafts. Seven days after contralateral nephrectomy all surviving animals had elevated serum creatinine and urea concentrations, along with decreased creatinine clearance, and they had secreted large volumes of dilute urine. Renal function was best in animals with isotonic-citrate-flushed grafts. After one month, significant improvement in urine osmolality, creatinine clearance, and serum creatinine had occurred only in the rats with citrate-flushed grafts. There were no significant differences between the citrate groups. All surviving rats had some residual renal cortical damage, but severe interstitial nephritis (greater than 30%) was much less frequent in the citrate groups.

Animals↗

Recovery of renal function after warm ischemia. I. The effect of chlorpromazine and phenoxybenzamine.

The effects of treatment with chlorpromazine (4 mg/kg) and phenoxybenzamine (1 and 5 mg/kg) on renal function and morphology after warm ischemia and contralateral nephrectomy were studied. Chlorpromazine pretreatment by intravenous injection 15 min before warm ischemia of 60 min resulted in the survival of all animals (cf. 75% in untreated group), with better renal function in the first week. Necrosis of the proximal convoluted tubule and ultimate residual cortical damage were less severe than in the untreated groups. Chlorpromazine was also beneficial after 75 min warm ischemia, although mortality was not reduced. Administration of chlorpromazine just prior to revascularization was ineffective, suggesting that sufficient concentration of the drug must be present in the kidney during the ischemic period or immediately after revascularization. Chlorpromazine probably protects the proximal tubular cells from ischemic damage. Phenoxybenzamine (1 mg/kg) was ineffective when administered 15 min before warm ischemia. A higher (5 mg/kg) dosage of the drug proved to be detrimental.

Animals↗

Treatment of gallstones by chenodeoxycholic acid.

Twenty-three patients with radiolucent gallstones in a functioning gallbladder were treated by orally administered chenodeoxycholic acid (750 mg/day) for periods ranging from six to 24 months. Complete dissolution of gallstones occurred in five patients, and partial dissolution occurred in four patients--an over-all response of 39%. Side effects of the treatment were minimal. Stone size was the major factor which influenced outcome, as seven of 15 patients with stones less than 1 cm in diameter had a reduction in stone size or dissolution of stones. It is recommended that chenodeoxycholic acid treatment should be reserved for the treatment of patients with radiolucent stones which are less than 1.5 cm in diameter.

Adult↗

Evaluation of citrate flushing solution using the isolated perfused rat kidney.

The isolated rat kidney perfused at 37 C with dialyzed bovine serum albumin (6.5 g/100 ml) in Krebs-Henseleit buffer was used to examine why a hypertonic citrate flush permits rapid recovery of renal function after storage. The composition of the original hyperosmolar citrate solution was varied so that the roles of osmolality, magnesium, and citrate could be evaluated. All kidneys were flushed with the test solutions and stored for 24 hr in the test solutions at 0 C. The citrate flushing solution requires both the citrate anion and magnesium for efficacy. Hyperosmolality does not enhance its action, an isosmolar solution is more effective. Citrate can be replaced by a nonmetabolizable analogue, tricarballylate, if the solution is suitably buffered. The mechanism of action of citrate is still uncertain, it does not seem primarily to act as a metabolic fuel or inhibitor.

Animals↗

The effect of added bran to the diet on the saturation of bilein people without gallstones.

Bran was added to the diet of eleven volunteers without gallstones, and its effect on bile saturation, bile acid profile in bile, and serum cholesterol and triglycerides was determined. Bile cholesterol saturation was decreased after two months of feeding bran to those female subjects who had supersaturated bile. Bran may be effective in decreasing the lithogenic potential of bile in people without gallstones, and further studies on its place in the prevention of gallstones in susceptible individuals are indicated.

Adult↗

Gallstone dissolution in man using cholic acid and lecithin.

Seven patients with radiolucent stones in the gallbladder and two patients with radiolucent stones in the biliary tree were treated with oral cholic acid and purified soya-bean lecithin for 6 months. In two patients the stones disappeared and in one patient the stones were reduced in size. In five patients fasting bile samples were obtained before and during treatment and assayed for cholesterol, bile acid, and phospholipid. In all five patients the lithogenic index of bile was reduced during treatment. The biliary deoxycholic acid concentration was increased and chenodeoxycholic acid concentration decreased during treatment.

Administration, Oral↗