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Biomedical subjects

G J Becker

Publications and source records attributed to G J Becker.

At least 73 records · Page 4Linked to original sources
PubMed1994

Should metallic vascular stents be used to treat cerebrovascular occlusive diseases?

The risks of metallic stent deployment are quite low, and the likelihood of restenosis due to intimal hyperplasia is relatively high, particularly in small to medium-size vessels. The goal of all cerebrovascular interventions is to alleviate symptoms and prevent stroke. For symptomatic carotid bifurcation stenosis, insufficient information is available regarding carotid PTA and stent placement to make any recommendations. Carotid endarterectomy is the treatment of choice in patients with a 70%-99% stenosis of the involved internal carotid artery. For internal carotid artery dissection, stent placement seems to be a reasonable therapeutic alternative that may eventually assume a position as an accepted therapeutic alternative alongside surgery and anticoagulation. The gathering of level I and level II evidence by means of well-designed clinical trials is encouraged. Similarly, the application of stent placement to occlusive disorders of the dural venous sinuses is intriguing. Additional clinical studies should help define the role of stents in these diseases.

Aortic Dissection↗
PubMed1994

Acute renal failure in IgA nephropathy.

Twenty-five (3%) of 865 patients with IgA nephropathy presented with acute renal failure (ARF). These patients were matched with 25 patients in the same series who presented with irreversible renal impairment. Patients with acute renal failure had a significantly higher incidence of macroscopic hematuria and red blood cells in tubules. Conversely, a greater percentage of patients with irreversible renal failure had > or = 40% sclerosed glomeruli. The long-term prognosis for patients presenting with ARF appears excellent with only 1 (4%) patient developing chronic renal failure after a mean follow-up of 65 months. Mechanisms of acute renal failure in IgA nephropathy are discussed.

Acute Kidney Injury↗
PubMed1994

Vasculopathy in cyclosporine-treated renal allografts: possible protection by diltiazem.

Morphometric quantitative analysis of the renal arterioles (arteriole wall thickness and overall vessel size) in renal biopsies from 21 cadaveric renal allograft recipients taken immediately prior to (0 months) and 3 months after transplantation was carried out using a computer-aided image analyzer. Patients (n = 10) who received standard therapy (cyclosporine, azathioprine and prednisolone) showed an increase in arteriole wall thickness at 3 months compared to 0 months (p < 0.01). Patients (n = 11) who received standard therapy and oral diltiazem (60 mg t.d.s.) showed no such change in the arteriole wall thickness between 0 and 3 months. As cyclosporine toxicity and/or chronic vascular rejection are associated with an increase in arteriole wall thickness, the differences observed in this study may imply a protective role for diltiazem on renal arterioles.

Adult↗
PubMed1994

Pregnancy-related complications in women with reflux nephropathy.

Three hundred and forty-five pregnancies in 137 women with reflux nephropathy have been studied. All pregnancies took place after 1971. Overall foetal loss was 48 (14%) of which only 6 (2%) were therapeutic abortions. Maternal complications (urine infection, hypertension, proteinuria, oedema, deterioration in renal function, hematuria or renal stones) occurred alone or in combination in 39% of pregnancies. Fifty-two pregnancies took place in women with plasma creatinine (P.Cr > 0.11 mmol/l) prior to conception. Foetal loss after 12 weeks gestation (excluding therapeutic abortions) was 18% compared with 8% in the 104 pregnancies where maternal P.Cr was known to be < or = o.11 per/l at conception (p < 0.05). Maternal complications were also more common in the impaired renal function group (p < 0.001). Comparison of pregnancies in women with unilateral versus bilateral renal scarring revealed no significant difference in foetal loss but an increased incidence of over 50% maternal complications in the bilateral renal scar group (p < 0.01). The incidence of pre-eclampsia was higher in women with bilateral renal scars, 50 (24%) than in women with unilateral scars 8 (7%) (p < 0.001). Persistent vesicoureteric reflux was not associated with increased foetal loss or maternal risk. Impaired renal function prior to conception is associated with increased foetal and maternal complications in pregnancy. Bilateral renal scarring is associated with increased maternal complications during pregnancy.

Abortion, Spontaneous↗
PubMed1994

Prevention of progression in non-diabetic chronic renal failure.

We have performed separate randomized prospective controlled studies on the effects of protein-restricted diet and angiotensin converting enzyme (ACE) inhibition on the rate of progression of non-diabetic renal failure. Renal function was assessed by creatinine clearance, reciprocal of plasma creatinine concentration and 51Cr-EDTA clearance. A protein-restricted diet (0.4 g per kg) resulted in a significantly lower rate of progression, as assessed by the slope of these parameters with time, when compared with a standard diet. ACE inhibition, when assessed by a mixed effect model, also significantly reduced the rate of progression. The many variables involved hinder trials of therapies directed against progression in non-diabetic renal failure.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

The potential for elderly donors to increase renal transplantation rates in Australia.

OBJECTIVE: To estimate the potential increase in renal donation rates if elderly donors (those over 60 years of age) were considered. DESIGN: Patients dying from acute brain damage resulting from stroke were identified using the Royal Melbourne Hospital (RMH) Stroke Service Register. Their records were retrospectively analysed to assess their eligibility as potential renal donors. SETTING: One hundred and ninety-eight patients dying from acute brain damage caused by stroke at a large metropolitan teaching hospital (RMH), from May 1987 to December 1990 inclusive. PATIENT ASSESSMENT: Patients were considered "eligible", "ineligible" or "possibly eligible" (requiring further assessment) as donors according to existing strict criteria (see methods) but irrespective of age. RESULTS: Of 198 stroke patients dying of brain damage, 92 satisfied the criteria of eligibility for renal donation; 51 of these were over 60 years old, yet only one became a renal donor. CONCLUSION: There is good evidence that elderly donors are acceptable for renal transplantation, yet they are not being referred. The consideration of elderly stroke victims as renal donors could have a dramatic effect on decreasing transplant waiting lists, increasing recipient patient well-being, and reducing hospital costs.

Adult↗
PubMed1993

Kidney transplantation from living related donors: a 19-year experience.

OBJECTIVE: To determine the outcome of patients with end-stage chronic renal failure treated by live donor renal transplantation at the Royal Melbourne Hospital and Royal Children's Hospital between 1973 and 1991, during which time two distinct immunosuppressive regimens were used. DESIGN: Data about live donor renal transplant recipients were retrieved from the Australian and New Zealand Dialysis and Transplantation Association Registry, to which we have submitted data on all transplant recipients at six monthly intervals since the commencement of our dialysis and transplant programs. PATIENTS: Seventy-two patients with chronic renal failure who received live donor renal transplants during the 19 years from February 1973 to February 1992 were included. MAIN OUTCOME MEASURES: Patient survival, transplant survival, transplant function, change in prednisolone requirements, and duration of hospital stay. RESULTS: The first 32 patients were treated with immunosuppressive regimens based on combinations of prednisolone and azathioprine ("dual therapy"), while the next 40 patients were treated with combinations of cyclosporin, prednisolone and azathioprine ("triple therapy"). Survival of patients in each group five years after transplantation was 97%. Actuarial graft survival at 5, 10 and 15 years in the dual therapy group was 58%, 52% and 47%, compared with a 5-year actuarial graft survival in the triple therapy group of 96%. There was no statistically significant difference in renal transplant function between the two groups within the first 6 years after transplantation. Twelve of 26 patients (46%) treated initially with triple therapy were able to stop treatment with prednisolone within 12 months of transplantation. Median hospital stay was 12 (range, 6-35) days during the period 1973-1985 and 8 (range, 5-20) days for the 1985-1992 period. CONCLUSION: Live donor renal transplantation has provided a highly satisfactory means of treating patients with end-stage chronic renal failure in the short and long term. Our recent experience indicates that excellent patient and graft survival and adequate renal function can be achieved by treating live donor renal transplant recipients with a triple immunosuppressive regimen of low dose cyclosporin, prednisolone and azathioprine.

Adolescent↗
PubMed1993

Reflux nephropathy: the glomerular lesion and progression of renal failure.

Reflux nephropathy is the cause of 5%-10% of dialysed end-stage renal failure. Once scarring has occurred, the prognosis depends on the severity of initial damage and the presence of proteinuria, which reflects the development of glomerulosclerosis. It is independent of ongoing reflux or infection. Histological appearances highly suggestive of reflux nephropathy can occur in radiologically normal kidneys. Duplex Doppler scans of ureteric orifices suggest these patients may have lateral insertion, suggesting past reflux. Glomerular hypertrophy correlates well with reduced renal function and severe renal scarring, but poorly with focal and segmental glomerulosclerosis, which correlates with proteinuria. Increasing attention is being paid to the tubulo-interstitium and the relationships between the cellular infiltrates (mainly T4 cells) and glomerular, tubular and vascular damage. Control of hypertension, hyperphosphataemia and a low-protein diet are the only currently widely accepted treatments for slowing progression.

Age Factors↗
PubMed1993

Collagen studies in newborn rat kidneys with incomplete ureteric obstruction.

Collagen studies in newborn rats with incomplete ureteric obstruction were performed to describe and quantify changes in collagen deposition resulting from urinary tract obstruction at an early developmental age. Incomplete ureteric obstruction was created in three-day-old rats by placing the left ureter in a tunnel formed by the psoas muscle, and sham-operated controls underwent a laparotomy. The rats were sacrificed at 10, 17, 24 or 31 days. Collagen types I, III, IV, and V were localized by indirect immunofluorescence microscopy, the total collagen content of the kidney was quantitated using hydroxyproline analysis, and collagen types I and III were quantitated using cyanogen bromide (CNBr) peptide analysis. Increased immunofluorescent staining for all of the collagens was found in the diffusely widened medullary interstitium of the obstructed kidney, and more focally in the cortical interstitium. Collagen types I, III and V, but not collagen type IV, were also found in bands in the interstitium at the junction of the cortex with the medulla. Increased staining for collagen type IV was found in thickened and tortuous tubular basement membranes (TBM) of the obstructed kidneys. The total collagen content of the obstructed kidney was significantly increased compared to the amounts in both the contralateral kidneys and in the kidneys from sham-operated controls at 24 and 31 days of age (P < 0.01 in each case, Wilcoxon matched pairs rank sum test and Mann Whitney U-test, respectively). The amount of collagen in the kidneys correlated with the degree of hydronephrosis (Spearman correlation test, r = 0.78, P < 0.02). CNBr peptide analysis demonstrated that over 50% of the collagen in the normal neonatal rat kidney was collagen type I and approximately 25% was collagen type III. In the obstructed kidneys most of the collagen was also collagen type I and collagen type III, although the proportion of total collagen comprised by these collagen types was decreased compared with the controls. The amount of collagen type III in the contralateral kidneys was reduced compared to that in the controls. Thus, the neonatal renal response to obstruction resulted in increased amounts of a range of collagens in the interstitium and TBM, and the extent of this response was partially related to the degree of hydronephrosis.

Animals↗
PubMed1993

Right atrial catheters: reliable, immediate and durable vascular access for haemodialysis and plasma exchange.

This paper prospectively evaluates 33 dual lumen, right atrial catheters inserted into either an external or internal jugular vein by open operation in 29 patients, of whom 15 required haemodialysis and 14 required temporary plasma exchange. The median (range) catheter survival in the haemodialysis and plasma exchange groups was 108 days (7-334 days) and 61 days (10-116 days), respectively. Life table analysis demonstrated that overall catheter survival was 58% at 200 days. The main causes of catheter failure were infection (four cases), poor flow (three cases) and accidental removal (one case). Another nine catheters were removed electively because of maturation of alternative methods of vascular access (five cases), completion of plasma exchange treatment (three cases), or successful renal transplantation (one case). Long-term silastic catheters, inserted into the right atrium via a jugular vein, have distinct advantages over temporary subclavian vein catheters and external arteriovenous (AV) shunts; this form of access is the method of choice for haemodialysis and plasma exchange patients who require immediate and short- to medium-term vascular access.

Adolescent↗
PubMed1993

Angioplasty, bypass surgery, and amputation for lower extremity peripheral arterial disease in Maryland: a closer look.

Tunis and colleagues attempted to assess the effect of peripheral angioplasty in a large population with descriptive epidemiologic methods. Their study suffered from a vague statement of purpose, inappropriate and inadequate outcome measures, undetermined differences in prevalence of peripheral vascular disease and prevalence of risk factors for bypass/amputation in 1989 versus 1979, no differentiation between levels of amputation or between primary and secondary amputation, lack of a unique ICD-9-CM code indicating angioplasty for peripheral vascular disease of the lower extremities, lack of unique patient identifiers, a mistaken perception of the adoption of angioplasty as "widespread" in Maryland, and the assumption of uniform coding accuracy throughout the period of study. We conclude that the study design of Tunis et al was inadequate to determine the beneficial effects of angioplasty or bypass surgery in the treatment of peripheral vascular disease. Moreover, the conclusion by Coffman (2) that "invasive procedures are indicated only for the severely ischemic limb" is completely unsupported by the study data. Physicians should not attempt to apply the results of the study by Tunis et al to individual case situations. It should be further appreciated that the study findings do not provide an adequate basis for policy-making decisions. It is clear that important clinical questions concerning the roles of angioplasty, bypass, and amputation should be answered with more definitive studies.

Algorithms↗