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Biomedical subjects

W M Bennett

Publications and source records attributed to W M Bennett.

At least 253 records · Page 14Linked to original sources
PubMed1983

Beneficial effect of pre-transplant splenectomy for leukopenia in primary cadaver kidney transplants.

Pre-transplant splenectomy is controversial. We compared 21 nondiabetic, transfused recipients of first cadaver kidney grafts who underwent pre-transplant splenectomy for steroid-resistant leukopenia to 114 without steroid-resistant leukopenia. Kidney graft survivals at 2 years were 80.2 plus or minus 8.9 and 48.5 plus or minus 5.3 per cent, respectively (p less than 0.05). The 2-year actuarial patient survivals were not significantly different (89.6 plus or minus 7.0 versus 87.8 plus or minus 3.9 per cent). Azathioprine doses and serum creatinine levels at 1 year were not significantly different. Pre-transplant splenectomy for steroid-resistant leukopenia resulted in a significant decrease in kidney graft losses owing to rejection without an increased risk of death of sepsis or thromboembolism.

Azathioprine↗
PubMed1983

Management of acute renal failure in sepsis--clinical considerations.

Current management of the septic patient with acute renal failure is summarized. Emphasis is given to the assessment of renal functional integrity in these situations as well as the recognition of nonoliguric acute renal failure, which is common in sepsis. Principles of antibiotic prescribing for critically ill patients are reviewed together with pertinent considerations for specific drugs.

Acute Kidney Injury↗
PubMed1983

Acute renal failure and tubular necrosis associated with hematuria due to glomerulonephritis.

A 16 year old male with a history of recurrent synpharyngitic macroscopic hematuria presented with severe loin pain, macroscopic hematuria and oliguric acute renal failure. Although renal biopsy showed mesangial IgA nephropathy with focal and segmental proliferation with crescents, the extent of glomerular involvement could not explain the severe functional disturbance. Intratubular obstruction and tubular necrosis secondary to the presence of severe glomerular bleeding provide a better explanation. Although renal failure resolved spontaneously, the long-term effects of episodes of this type on structure and function is unknown.

Acute Kidney Injury↗
PubMed1982

Comparison of standard immunosuppression with adjuvant antilymphoblast globulin in primary cadaver kidney transplant survival.

Adjuvant, prophylactic, antilymphoblast globulin and standard immunosuppression have produced comparable long-term cadaver kidney graft survivals at separate institutions. A comparison was made of 35 primary cadaver kidney grafts into recipients treated with prophylactic, adjuvant antilymphoblast globulin to 55 recipients of primary cadaver kidney grafts treated with standard immunosuppression. Antilymphoblast globulin delayed early rejection episodes (P under 0.05), making early post-transplant management simpler. There were no significant differences between the two groups with respect to graft losses due to rejection at any interval beyond one month.

Antilymphocyte Serum↗
PubMed1982

Natural history of "silent" lupus nephritis.

Twenty patients with systemic lupus erythematosus but without evident renal involvement previously underwent percutaneous renal biopsy. Findings revealed almost universal pathologic evidence of nephritis. Included were three patients who had diffuse proliferative changes and five who had subendothelial electron dense deposits. Only four patients developed clinical renal disease during the follow-up period while no patient died or required dialysis. Using the Life Table Method, the cumulative percentage of patients free from any clinical renal disease was over 60% at 10 yr from the time of diagnosis of systemic lupus, and at 8 yr from the time of the original biopsy. It is concluded that silent lupus nephritis, regardless of histologic subtype, has a favorable prognosis. These data may not be applicable to patients with similar biopsies who have evidence of clinical lupus nephritis.

Actuarial Analysis↗
PubMed1982

Parathyroid function in persistent hyperparathyroidism: relationship to gland size.

The release of parathyroid hormone in experimental animals is related inversely to the plasma calcium concentration. The relevance, though, of these observations to the dynamics of parathyroid function in normal and hyperparathyroid humans is uncertain. We assessed the in vivo parathyroid hormone response to changes in extracellular calcium in 8 normal subjects and 15 patients with persistent hyperparathyroidism following renal transplantation. In 12 hyperparathyroid patients, the hormone response was related to their total gland size measured at the time of their parathyroidectomy. Plasma ionized calcium, magnesium, and parathyroid hormone concentrations were measured in the basal state and during a 2-hr infusion of EDTA (50 mg/kg), and a 4-hr calcium infusion (15 mg/kg). The parathyroid function curves of both groups of subjects (P less than 0.001) fit a log-linear relationship. The slopes of the respective parathyroid function curves were similar, although the hyperparathyroid curve was shifted to the right (P less than 0.0001). Gland size was not predicted by basal PTH levels; however, it did correlate with changes in parathyroid hormone induced by EDTA (P less than 0.001) and calcium (P less than 0.001). We conclude that the in vivo sensitivity of hyperplastic glands to changes in plasma calcium is maintained. The excessive secretion of immunoreactive parathyroid hormone in chief cell hyperplasia primarily reflects total gland mass. Our results indicate that the assessment of the dynamics of parathyroid response, rather than measurements of static plasma parathyroid hormone and calcium concentrations, should be further investigated as a more rational application of radioimmunoassays in the evaluation of the parathyroid axis.

Adult↗
PubMed1982

Sex-related differences in the susceptibility of rats to gentamicin nephrotoxicity.

Age-matched male and female Fischer 344 rats were treated with gentamicin, 40 mg/kg of animal body weight per day, for three to 21 days. Renal dysfunction was less severe in females as measured by concentrations of blood urea nitrogen and creatinine and by cortical slice uptake of p-aminohippuric acid and N1-methylnicotinamide chloride. Also, cortical concentrations of gentamicin in females were lower than in males. Neither exogenous testosterone administered to adult females nor castration of prepubertal males changed the pattern of dysfunction. These results show that sex affects susceptibility to aminoglycoside nephrotoxicity by mechanisms that are undefined but that are apparently unrelated to testosterone. The variable of sex needs to be considered in interpreting the results of studies of experimental aminoglycoside nephrotoxicity.

Animals↗
PubMed1982

Reduction of experimental gentamicin nephrotoxicity in rats by dietary calcium loading.

Since gentamicin accumulates in the renal cortex before renal failure and calcium reduces gentamicin binding to cell membranes, we examined the effect of dietary calcium loading on gentamicin toxicity in male F344 rats. Rats were fed either a normal (0.5%)- or a high (4%)-calcium-content chow. Calcium loading did not alter inulin clearance, urinary excretion of sodium or total osmoles, or serum ionized calcium. However, calcium loading caused elevation of urinary calcium excretion and lowered urinary cyclic AMP levels. The data suggest that calcium loading may have slowed the accumulation of gentamicin (40 mg/kg per day) by the renal cortex. Histological and functional evidence of nephrotoxicity was delayed in onset and attenuated in magnitude. The results indicate that dietary calcium loading reduces experimental gentamicin nephrotoxicity. Protection may be associated with slower renal cortical accumulation of gentamicin. Calcium-dependent membrane or intracellular events may mediate this effect.

Animals↗
PubMed1982

Change in serum bicarbonate during acute EDTA infusions in post-transplant hyperparathyroidism.

We evaluated the effect of endogenous parathyroid hormone (PTH) on serum bicarbonate in 12 patients with postrenal transplant hyperparathyroidism. EDTA-induced hypocalcemia produced a significant rise in serum PTH (p less than 0.001). Associated with the increase in PTH was a significant fall in plasma bicarbonate (p less than 0.001) and increase in the chloride: phosphorus ratio (p less than 0.001). Magnesium remained stable but serum potassium fell in response to EDTA. These observations suggest that endogenous PTH can significantly affect plasma bicarbonate in vivo and may contribute to post renal transplant renal tubular acidosis.

Bicarbonates↗
PubMed1982

Gentamicin nephrotoxicity. I. Degree and permanence of acquired insensitivity.

Insensitivity to the nephrotoxic effects of gentamicin develops in F344 rats during the course of gentamicin-mediated acute renal failure. Functional and structural recovery occur thereafter in spite of continued gentamicin administration. To determine the degree of insensitivity, we compared structural and functional recovery of rats treated continuously with gentamicin to rats in which gentamicin was stopped after 14 days, at the height of dysfunction. Continued treatment did not reduce the rate or ultimate degree of recovery of structure, CIn, or in vitro renal cortical PAH uptake; however, both the rate and degree of recovery of NMN uptake were reduced in continuously treated animals. Furthermore, doubling the dose of gentamicin during the recovery period overcame insensitivity, causing a second episode of acute renal failure. The permanence of insensitivity was examined by re-treating rats 6 months after recovery from gentamicin-mediated acute renal failure. There was no evidence of residual resistance to gentamicin nephrotoxicity in these animals. These results indicate that although gentamicin insensitivity is substantial, it is not complete, as indicated by low-grade, ongoing tubular toxicity to the organic base transport system and sensitivity to higher doses of gentamicin. Furthermore, insensitivity is a transient phenomenon.

Acute Kidney Injury↗
PubMed1982

Structural and functional effects of long-term lithium therapy.

To determine the effects of long-term lithium therapy, we have studied the renal histology and the renal function of 47 patients with affective disorders who were either currently receiving or had previously received maintenance lithium therapy (lithium patients), and we have compared the results with those of 32 other psychiatric patients with similar affective illnesses who had never taken lithium (prelithium patients). The renal biopsy samples, analyzed by a point-counting technique for interstitial fibrosis, were not different in degree between the lithium and the prelithium patients. Interstitial fibrosis was also not different between prelithium patients and age-matched transplant donor kidney controls, but it was greater in lithium patients when compared with the donor kidney controls (P less than 0.01). The specific distal tubular lesion associated with lithium therapy was present in all the biopsy samples of the patients who were currently receiving lithium therapy. Marked distal nephron dysfunction, as measured by urinary concentrating ability (P less than 0.0001) and urinary acidification (P less than 0.0001), was evident in lithium patients compared with the prelithium patients. These defects were correlated with the duration of lithium therapy. Serum creatinine estimations (P less than 0.01), serum beta-2 microglobulins (P less than 0.01), and 51Cr-EDTA clearances (P less than 0.01) suggested some impairment of GFR in lithium patients compared with prelithium patients. These defects did not correlate with the duration of lithium therapy. From these studies we concluded that the marked distal nephron dysfunction induced by lithium might produce prerenal impairment of GFR because the renal function abnormalities have no structural basis when the degree of interstitial fibrosis of other psychiatric patients is used as a control. Prospective studies are needed to answer the controversial question of whether stable maintenance lithium therapy produces chronic nephrotoxicity.

Adult↗
PubMed1982

Effect of basis amino acids and aminoglycosides on 3H-gentamicin uptake in cortical slices of rat and human kidney.

The uptake of 3H-gentamicin was assessed in renal cortical slices of Fischer 344 male rats and four human cadaver kidneys not utilized for renal transplantation. In both species the uptake was maximal at 90 min and maintained a steady state thereafter. The characteristics of the energy-dependent component of 3H-gentamicin uptake were not altered by various basic amino acids, but competitive inhibition was induced by other aminoglycosides in a dose-dependent fashion. Thus aminoglycosides appear to share a transport process that is distinct from those of organic bases or other cationic substances. In addition, under the experimental conditions employed, the basolateral membrane of the tubular cell is capable of energy-dependent uptake of gentamicin. The role of this route of cellular uptake of aminoglycoside in clinical nephrotoxicity is speculative.

Amino Acids↗