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Biomedical subjects

H A Austin

Publications and source records attributed to H A Austin.

At least 55 records · Page 3Linked to original sources
PubMed1989

Dynamic Gd-DTPA-enhanced MR imaging of the kidney: experimental results.

To determine the normal appearance of dynamic enhanced renal magnetic resonance (MR) images, 25 rabbits were injected with Gd-DTPA and 32 consecutive gradient-recalled images were acquired. Several rabbits were also imaged in dehydrated (five animals) and overhydrated (seven animals) states. A reproducible renal enhancement pattern is observed that can be divided into three phases. During the first phase, a peripheral dark band appears, probably representing arrival of Gd-DTPA within the arterioles and vasa recta. The second phase begins as a second dark band migrating centripetally toward the medulla; this likely represents the concentration of Gd-DTPA in the descending limb of the loop of Henle. The third phase is characterized by a gradual darkening in the papilla, probably caused by concentration of Gd-DTPA within the collecting ducts. Hydration status influences the duration of these phases. These observations can be explained by the anatomy and physiologic characteristics of the nephron, as well as the MR characteristics of Gd-DTPA at different concentrations.

Animals↗
PubMed1989

Evolution of ciclosporin nephrotoxicity in patients treated for autoimmune uveitis.

Among 73 patients treated with ciclosporin (CS) for autoimmune uveitis, a 50% elevation of serum creatinine was observed in 37% within 3 months of starting CS and in 25% after more than 6 months of relatively uncomplicated therapy. Sequential renal function and histologic evaluations were performed in 17 patients to further characterize the nephrotoxic effects of long-term CS therapy. Inulin clearance remained essentially unchanged in 12 patients despite CS dosage reductions in the majority. In 2 such patients, repeat renal biopsy specimens revealed evidence of progressive irreversible kidney injury even though renal function was stable. Inulin clearance decreased substantially in 3 patients; in 1 case a follow-up renal biopsy showed increased severity of chronic histologic change. For 2 patients, the inulin clearance more than doubled after CS dosage reduction; and in 1 of those cases, repeat renal biopsy showed no evidence of progressive renal scarring. Overall, the morphologic attributes of irreversible kidney injury (designated by a chronicity index including glomerular sclerosis, tubular atrophy and interstitial fibrosis) were increased in 3 of 6 follow-up renal biopsy specimens. Histologic alterations of renal arterioles, including hyaline change, were observed in all CS-treated patients. The hyaline change of arterioles was either extensive in the first renal biopsy specimen or became extensive in the second biopsy in the 3 cases manifesting an increased chronicity index on the follow-up renal biopsy. Thus, parenchymal injury can progress in some cases despite CS dosage reduction and stable renal function; renal arteriolar histologic change is a prominent finding in these patients. Patients that exhibit a substantial improvement in renal function after dosage reduction may experience a more favorable course.

Autoimmune Diseases↗
PubMed1989

Chronic dialysis in a patient with cystic fibrosis.

To our knowledge this is the first case reported in the literature of a patient with cystic fibrosis and end-stage renal disease, who was on dialysis for 2 years. We discuss here the possible mechanisms responsible for what has been called 'the cystic fibrosis nephropathy' and its consequences.

Adult↗
PubMed1988

Cyclosporin A in severe, treatment-refractory rheumatoid arthritis. A randomized study.

STUDY OBJECTIVE: To assess the efficacy and toxicity of cyclosporin A in patients with severe, treatment-refractory rheumatoid arthritis. DESIGN: Prospective randomized, double-blind 6-month trial. PATIENTS: Thirty-one patients who had classic seropositive rheumatoid arthritis with active synovitis unresponsive to conventional therapy. INTERVENTIONS: Patients were randomly assigned to high-dose (10 mg/kg body weight.d) or low-dose (1 mg/kg.d) cyclosporin A therapy. A reduction in the dose was permitted for adverse side effects. After 6 months of therapy, patients who showed clinically relevant improvement, defined as a 40% or greater reduction in their total joint activity score, were given the option to continue receiving the therapy for an additional 6 months. MEASUREMENTS AND MAIN RESULTS: At 6 months, clinically relevant improvement occurred in 10 of 15 patients (95% CI, 38 to 88) receiving high-dose therapy and in 4 of 16 patients (CI, 7 to 52) receiving low-dose therapy (P = 0.02). Statistically significant improvements in individual measures were shown only in the high-dose group. Improvements were noted in the number of tender joints (-18.8; CI, -24.5 to -13.1) and swollen joints (-12.1; CI, -15.4 to -8.6), as well as in physician's global scores (-1.5; CI, -2.1 to -0.9) and patient's global scores (-1.1; CI, -1.9 to -0.5). Improvement in disease activity was maintained through 12 months in the high-dose group. The clinical responses to cyclosporin A were most evident in patients with depressed in-vitro proliferative responses of peripheral blood mononuclear lymphocytes to soluble recall antigens. Toxicities, such as fatigue, gastrointestinal and neurologic complaints, and hypertrichosis were frequent but often reversible with a reduction in the dose. Nephrotoxicity, with a 20% increase in the serum creatinine level, was seen in 27 of 31 patients (CI, 71 to 97). CONCLUSIONS: Cyclosporin A is an effective therapy for severe, treatment-refractory rheumatoid arthritis. Side effects, particularly nephrotoxicity, are common.

Adult↗
PubMed1988

Renal disease in systemic lupus erythematosus.

Lupus nephritis is the archetype of diseases caused by the deposition of immune complexes. The characteristics which render only a portion of circulating immune complexes nephritogenic are not well delineated, but cat-ionic charge of antigen and/or antibody may contribute. Lupus nephritis is characterized by extreme diversity of clinical manifestations and pathologic features. Scrupulous monitoring of urinary sediment and renal function tests is necessary to identify renal involvement in a phase which is amenable to therapeutic intervention. Evaluation of renal biopsies also assists in development of indications for therapy. The pathology of lupus nephritis is classified primarily as mesangial, focal proliferative, diffuse proliferative, and membranous nephropathy. Indexes of activity and of chronicity provide a succinet description of the balance of reversible and irreversible disease. The activity index incorporates glomerular hypercellularity, karyorrhexis/fibrinoid necrosis, leucocyte exudation, hyaline thrombi, cellular crescents, and interstitial inflammation. The chronicity index incorporates glomerular sclerosis, fibrous crescents, tubular atrophy, and interstitial fibrosis. Delineation of the activity and chronicity indexes also facilitates the assessment of prognosis and the ordering of indications for therapy.

Humans↗
PubMed1988

Lupus nephritis: association between serology and renal biopsy measures.

The relationship between serologic tests and renal histologic change over time was examined in 55 patients with lupus nephritis. After a median interval of 40 months on various immunosuppressive drug regimens, C3 complement levels were improved in 78% of patients and anti-DNA levels were improved in 85%. Comparison of initial and followup renal pathology showed that the activity index of the biopsy improved in 82%, while the chronicity index worsened in 71% of patients. Normalization of C3, but not anti-DNA levels, was associated with a lowering of the activity index on repeat biopsy. Prolonged depression of serum C3 levels was associated with a trend (p = 0.066) towards worsening of the chronicity index, but the change in chronicity index showed no relationship to the duration of elevated anti-DNA. Our studies indicate that abnormal levels of C3 complement are predictive of the degree of persistently active glomerular disease, but that duration of abnormal C3 or anti-DNA are less consistent predictors of the acquisition of chronic, irreversible renal lesions.

Antibodies, Antinuclear↗
PubMed1988

Metabolic and renal effects of interleukin-2 immunotherapy for metastatic cancer.

The systemic administration of recombinant interleukin-2 (IL-2) either alone or in combination with lymphokine activated killer cells is a new approach to the immunotherapy of metastatic cancer in man. Renal toxicity is often a dose-limiting side effect of IL-2 administration. This prospective study of 17 consecutive patients receiving parenteral high dose IL-2 documents a reversible syndrome of hypotension, oliguria, fluid retention, azotemia and very low urinary excretion of sodium (median FeNa of 0.04%). The median nadir urinary uric acid to urinary creatinine ratio during IL-2 therapy was 0.2. This IL-2 regimen induces a reversible renal hypoperfusion syndrome (pre-renal azotemia) without evidence of acute uric acid nephropathy. Hypophosphatemia [median serum phosphorus of 1.9 mg/dl (0.61 mmol/l)] prompted further study of tubular function. Urinary excretions of phosphorus, calcium and magnesium were very low. Arterial blood gases revealed hyperventilation without alkalemia. The hypophosphatemia probably reflects increased utilization of inorganic phosphorus by rapidly proliferating lymphoid cells.

Acute Kidney Injury↗
PubMed1987

Reduced systemic drug exposure by combining intraarterial cis-diamminedichloroplatinum(II) with hemodialysis of regional venous drainage.

During cancer chemotherapy toxicity to normal tissues often limits the tolerable dose. To increase drug delivery to tumor while maintaining tolerable systemic exposure, regional treatments, such as intraarterial drug delivery, have been used. Despite intraarterial delivery, systemic toxicity often remains the dose-limiting sensitivity. If systemic drug exposure could be reduced after intraarterial infusion, the intraarterial dose could be increased, which should increase the therapeutic response. We compared the pharmacokinetic advantage after cisplatin infusion into the internal carotid artery to that obtained after infusing cisplatin into the internal carotid artery during extracorporeal removal of cisplatin from the jugular blood by hemodialysis. Four patients with malignant gliomas received intracarotid cisplatin, 100 mg/m2 over 60 min, every 4 weeks. During one treatment, while cisplatin was infused into the internal carotid artery, the jugular blood was dialyzed extracorporeally at 300 ml/min and returned to the inferior vena cava. Seventy to 96% of the free platinum that entered the dialyzer was removed. By aspirating blood from the jugular vein at 300 ml/min, 30-79% of the ipsilateral carotid blood was collected for extracorporeal circulation. Hemodialysis of the cerebral venous drainage during intracarotid infusion reduced the systemic exposure to cisplatin by 51-61% when compared to the exposure from internal carotid artery infusion without hemodialysis. The pharmacokinetic advantage (brain/body exposure ratio) was increased from 3 to 5/1 during internal carotid artery infusion alone to as much as 15/1 during treatment combining intracarotid infusion with hemodialysis of the jugular blood. Systemic toxicity now limits the dose of cisplatin that can be administered safely. Increased tumor exposure without increased systemic toxicity may be possible with the technique described and greater doses of cisplatin. Assuming no associated local toxicities, the results of the current study indicate that the dose of intracarotid cisplatin can be increased while maintaining tolerable systemic exposure.

Brain Neoplasms↗
PubMed1987

Severe glomerulonephritis with late emergence of classic Wegener's granulomatosis. Report of 4 cases and review of the literature.

We have analyzed an unusual group of 19 patients (15 previously reported) with Wegener's granulomatosis, who presented with severe glomerulonephritis and developed diagnostic respiratory lesions only after 4 to 78 months. Necrotizing glomerulonephritis, often with crescents, and rarely with vasculitis, was the predominant renal lesion. Wegener's granulomatosis was unsuspected initially, since systemic manifestations, such as fever, arthralgias, malaise, and even pulmonary hemorrhage, were nonspecific or transient, and because renal biopsy findings resembled those seen in microscopic polyarteritis or idiopathic crescentic nephritis. Despite therapy, usually with corticosteroids, only 4 patients maintained adequate renal function. Most patients were receiving chronic dialysis when respiratory involvement developed. Cavitary nodular pulmonary infiltrates were seen in 12 of the 17 patients with lung involvement, and otorhinological disease occurred in 10 patients. Arthralgias, fever, and cough, with or without hemoptysis, were common. Wegener's granulomatosis was diagnosed by lung biopsy in 15 cases and by nasal biopsy in 4. Specific treatment was required for the respiratory disease and was delayed in many patients, because of lack of awareness that Wegener's granulomatosis may present with primary glomerulonephritis and become active during chronic renal failure or dialysis. Nevertheless, all but 1 patient eventually responded to treatment, although 3 additional patients died of late complications.

Acute Disease↗
PubMed1987

NIH conference. Lupus nephritis.

Nephritis has long been considered one of the most ominous components of systemic lupus erythematosus. Accumulations of immune complexes and lymphoid cells in several locations within the kidney are the best-described elements of lupus nephritis. The extreme diversity of the renal changes indicates that many variables are likely to be involved. Inbred strains of lupus-prone mice have provided homogeneous subjects for study of pathogenesis and response to treatment. Comparable grouping of lupus nephritis in humans according to unique or dominant pathogenetic mechanisms is imprecise and limited by insufficient knowledge of the primary stimulus for the disease. Treatment is also imperfect and, at times, hazardous. Certain regimens incorporating cytotoxic drugs provide a significant therapeutic advantage over corticosteroids alone in the management of this disease.

Adult↗
PubMed1987

Effects of interleukin-2 on renal function in patients receiving immunotherapy for advanced cancer.

Adoptive transfer of autologous lymphokine-activated killer cells in conjunction with recombinant interleukin-2 in patients with advanced cancer has produced significant regression of metastatic disease in selected patients. We analyzed the effects of interleukin-2 regimens on renal function in 99 consecutive patients. Interleukin-2 therapy with or without lymphokine-activated killer cells was associated with varying degrees of hypotension, fluid retention, azotemia, oliguria, and low fractional sodium excretion. After the patients completed the interleukin-2 regimens, their renal function improved promptly. Renal function values returned to baseline levels within 7 days in 62% of patients, within 14 days in 84%, and within 30 days in 95%. Pretherapy serum creatinine values above 1.4 mg/dL predicted the severity of azotemia and prolonged duration of renal functional recovery, interleukin-2 therapeutic regimens induce prerenal azotemia. Careful selection of patients and early detection of adverse physiologic changes may alleviate the side effects of interleukin-2 therapy.

Adolescent↗
PubMed1987

Studies of immunosuppressive drugs in the treatment of lupus nephritis.

Long-term, controlled trials to evaluate the efficacy and toxicities of immunosuppressive drug therapies compared to treatment with corticosteroids alone in the management of patients with lupus nephritis have been performed. The studies demonstrate that immunosuppressive drug regimens, particularly intravenous cyclophosphamide, reduce the likelihood of end-stage renal failure. However, toxicities such as herpes zoster and ovarian failure were found to be increased in patients with cyclophosphamide.

Child↗
PubMed1986

Renal histopathologic alterations in patients treated with cyclosporine for uveitis.

To evaluate abnormalities of renal morphology associated with long-term cyclosporine therapy, we obtained percutaneous renal biopsy specimens from 17 patients who had been treated for autoimmune uveitis with cyclosporine for an average of two years. For comparison, we also analyzed renal biopsy specimens from patients with idiopathic hematuria who had not received cyclosporine. The atrophic and sclerosing glomerular and tubulointerstitial lesions in the specimens were assessed to derive a chronicity index. The specimens from the patients treated with cyclosporine showed a significantly higher chronicity index than those from the controls (P less than 0.00005). All patients who had received cyclosporine had interstitial fibrosis, tubular atrophy, or both. A good functional predictor of the abnormalities in renal morphology was the length of time that a patient's serum creatinine had exceeded the base-line value by more than 50 percent. Chronic pathologic alterations were seen even in patients who had normal renal function at the time of the biopsy. In conjunction with sequential measurements of renal function, renal biopsy may have an important role in defining the type and degree of nephrotoxicity that can develop in patients receiving long-term cyclosporine therapy for autoimmune disease.

Adolescent↗
PubMed1986

Therapy of lupus nephritis. Controlled trial of prednisone and cytotoxic drugs.

We evaluated renal function in 107 patients with active lupus nephritis who participated in long-term randomized therapeutic trials (median follow-up, seven years). For patients taking oral prednisone alone, the probability of renal failure began to increase substantially after five years of observation. Renal function was better preserved in patients who received various cytotoxic-drug therapies, but the difference was statistically significant only for intravenous cyclophosphamide plus low-dose prednisone as compared with high-dose prednisone alone (P = 0.027). The advantage of treatment with intravenous cyclophosphamide over oral prednisone alone was particularly apparent in the high-risk subgroup of patients who had chronic histologic changes on renal biopsy at study entry. Patients treated with intravenous cyclophosphamide have not experienced hemorrhagic cystitis, cancer, or a disproportionate number of major infections. We conclude that, as compared with high-dose oral prednisone alone, treatment of lupus glomerulonephritis with intravenous cyclophosphamide reduces the risk of end-stage renal failure with few serious complications.

Administration, Oral↗
PubMed1986

Renal tubular function in cyclosporine-treated patients.

Renal tubular function was studied in 32 consecutive patients treated with cyclosporine for autoimmune uveitis. Cyclosporine dosage was modified to maintain the serum creatinine level at less than 2 mg/dl. No evidence of aminoaciduria, glucosuria, hypokalemia, hypophosphatemia, or hypouricemia indicative of the Fanconi syndrome was detected during three to six months of observation. The renal tubular reabsorption of phosphate, determined by renal threshold phosphate concentration (TmPO4/GFR), remained unchanged. An early decrease in the serum magnesium level was accompanied by a decrease in daily urinary magnesium excretion. Concurrent with the development of a mild reduction of the glomerular filtration rate, the fractional excretion of magnesium was slightly higher and that of calcium was lower than pretreatment values. There were modest elevations of serum uric acid and potassium values. Furthermore, lysozymuria was not observed. Thus, the alterations in tubular functions observed in our cyclosporine-treated patients are comparable to those associated with mild chronic renal insufficiency of various causes and are not specific manifestations of cyclosporine tubular toxicity.

Adolescent↗
PubMed1986

Glioblastoma: catheter techniques for isolated chemotherapy perfusion.

Techniques have been developed for isolated perfusion of chemotherapeutic agents in patients with glioblastoma. Three catheters that facilitate crossing the carotid siphon have been developed; two are based on an everting or toposcopic principle, and one uses microjets for deflectability and improved mixing. Blood from the ipsilateral jugular vein is aspirated at high volumes (300 ml/min) for extracorporeal circulation through an adsorption column (for recovery of carmustine) or dialysers (for recovery of cisplatin). Preliminary experience in 10 patients suggests that high doses of chemotherapeutic agent can be administered using these catheters, with reduced retinal and systemic toxicity.

Brain Neoplasms↗