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Biomedical subjects

A C Novick

Publications and source records attributed to A C Novick.

At least 145 records · Page 8Linked to original sources
PubMed1995

Role of endothelium-derived relaxing factor in the maintenance of renal blood flow in a rodent model of chronic hydronephrosis.

OBJECTIVES: To define the role of endothelium-derived relaxing factor (EDRF) in the regulation of renal hemodynamics in the hydronephrotic kidney. METHODS: Experiments were performed in control rats and in rats that had undergone unilateral ureteral ligation 6 weeks before. Renal blood flow was monitored before and after inhibition of EDRF synthesis in the control and hydronephrotic animals. Videomicroscopy was also performed in hydronephrotic animals to observe directly the effect of inhibition of EDRF synthesis on the renal microcirculation. RESULTS: Inhibition of EDRF synthesis resulted in a 61% decrease in renal blood flow in the control animals compared with only a 27% decrease for the hydronephrotic animals. The videomicroscopy studies demonstrated that inhibition of EDRF synthesis results in significant vasoconstriction of the preglomerular and postglomerular resistance vessels. CONCLUSIONS: Although EDRF continues to play a significant role in the maintenance of renal blood flow in the chronically obstructed kidney, EDRF synthesis by the renal vascular endothelium may be reduced in this setting, contributing to ischemic renal atrophy.

Acetylcholine↗
PubMed1995

Diagnostic tunica vaginoscopy in a rodent model of testicular torsion.

OBJECTIVES: To evaluate the effectiveness of percutaneous endoscopy of the tunica vaginalis for identifying testicular torsion in a rodent model. METHODS: One testis was randomly selected in 10 Wistar rats weighing 500 to 600 g. Following 2 hours of 720 degree torsion, bilateral percutaneous endoscopy of the tunica vaginalis was performed by a blinded investigator utilizing a 70 degree cystoscope lens through a single midline 3 to 4 mm scrotal cutdown incision. RESULTS: Using this technique, the blinded investigator was able to identify the torsed testis rapidly in every case, which was distinguished by its cyanotic color and by the size and color of the testicular surface vessels. CONCLUSIONS: Tunica vaginoscopy is a simple, accurate, rapidly performed, minimally invasive, diagnostic technique in this experimental model of testicular torsion.

Animals↗
PubMed1995

Renal arteriovenous malformations masquerading as renal cell carcinoma.

Renal arteriovenous malformations may have varied clinical and radiographic appearances. Often, it remains difficult to distinguish these lesions from renal cell carcinomas to tailor the most appropriate diagnostic evaluation and therapy. We have encountered 6 patients with renal arteriovenous malformations that masqueraded as renal cell carcinomas and describe their clinical presentation and management.

Adult↗
PubMed1995

Effect of angiotensin-converting enzyme inhibition on nephropathy in patients with a remnant kidney.

OBJECTIVES: This study was performed to evaluate the effect of angiotensin-converting enzyme inhibitor (ACEI) therapy and dietary protein restriction on nephropathy involving a remnant kidney. METHODS: Five patients with proteinuria > or = 5 years following partial removal of a solitary kidney were treated with a low-protein diet and an ACEI agent. Four patients had biopsy-proven focal segmental glomerulosclerosis. The daily urinary protein excretion ranged from 1240 to 10,032 mg. The serum creatinine levels ranged from 1.2 to 3.1 mg/dL. RESULTS: The post-treatment follow-up interval ranged from 18 to 30 months. The treatment regimen was well tolerated in all patients. Four patients experienced a reduction in the urinary protein level while maintaining stable overall renal function. In 1 patient, the urinary protein level increased and renal function gradually deteriorated following ACEI therapy. CONCLUSIONS: These preliminary data suggest that ACEI therapy and a low-protein diet may mitigate nephropathy associated with a remnant kidney.

Adult↗
PubMed1995

Three-dimensional analysis of glomerular morphology in patients with subtotal nephrectomy.

Previous studies documented that single section examination of kidney tissue underestimates glomerulosclerosis and that three-dimensional examination of glomerular morphology improves recognition of the incidence and distribution of sclerotic changes within the glomerular capillary tuft. We have adopted this technique to evaluate the true frequency and the spatial extent of glomerulosclerosis in patients who were subjected to extensive renal mass reduction. We re-evaluated four kidney biopsies of patients with a solitary kidney who had undergone partial nephrectomy for renal-cell carcinoma. Histopathological examination aimed at detection of glomerular sclerotic lesions was performed on serial sections (from 75 to 93 serial sections for each biopsy, 3 microns thick) together with three-dimensional morphometric analysis of glomerular tuft and sclerotic areas using a computer-based image processing system. Results were compared with observations based on more conventional single section evaluation of the same biopsies. Among 65 glomeruli examined by three-dimensional morphometric analysis, only 8% were normal, 42% revealed segmental sclerosis and 51% global sclerosis. These results confirmed that single section evaluation grossly overestimates the number of normal glomeruli (37% vs. 8%, respectively), since the majority of glomeruli classified as normal are indeed affected by sclerotic changes in areas typically out of the section plane. The three-dimensional distribution of sclerosis is characterized by the appearance of multi-focal areas affecting a small capillary tuft volume (< 10%) which ultimately propagate to the entire capillary tuft. Despite the maintenance of renal function, at the time of biopsy in patients with extensive ablation of renal mass, the incidence of glomerulosclerosis affects almost the entire glomerular population.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1995

Reversible renin mediated massive proteinuria successfully treated by nephrectomy.

We report on a patient with severe hypertension and nephrotic range proteinuria, which were renin mediated in origin. Aortography demonstrated occlusion of the right renal artery and renal vein renin measurements lateralized strongly to the right kidney. Removal of the right kidney led to amelioration of hypertension and proteinuria. Massive proteinuria in this setting is due to high levels of intrarenal angiotensin II and is reversible with deactivation of the renin-angiotensin system.

Aged↗
PubMed1995

Surgical treatment of renovascular hypertension in moyamoya disease: case report and review of the literature.

Moyamoya disease is a rare disorder characterized by progressive occlusive cerebral arteriopathy associated with an extensive network of collateral vessels. Renovascular hypertension has rarely been associated with this disease. We report on a girl with renovascular hypertension and 2 renal artery aneurysms who was found to have moyamoya disease. Successful surgical treatment was achieved with extracorporeal arterial repair and renal autotransplantation. The relationship between moyamoya disease and renovascular hypertension is reviewed.

Child↗
PubMed1995

The contemporary role of extra-anatomical surgical renal revascularization in patients with atherosclerotic renal artery disease.

We delineate the current role of extra-anatomical revascularization techniques in the treatment of patients with atherosclerotic renal artery stenosis. There are 2 components to this study. In part 1 all abdominal aortograms performed between 1989 and 1993 were reviewed to document the presence of significant abdominal aortic and visceral arterial atherosclerosis in patients with atherosclerotic renal artery stenosis. A total of 254 patients with atherosclerotic renal artery stenosis was identified. Among 44 patients with severe unilateral disease the incidence of significant abdominal aortic atherosclerosis was 75%. The incidence of significant (greater than 50%) stenosis of the celiac, right common iliac and left common iliac arteries was 52%, 32% and 27%, respectively. In 129 patients with severe atherosclerotic renal artery stenosis bilaterally or in a solitary kidney the incidence of significant abdominal aortic atherosclerosis was 81%, and the incidence of significant (greater than 50%) stenosis of the celiac, right common iliac and left common iliac arteries was 59%, 57% and 59%, respectively. These data indicate that hepatorenal, splenorenal and iliorenal bypass cannot be performed in many patients with atherosclerotic renal artery stenosis due to significant disease involving the donor vessels for these operations. In part 2, all patients undergoing surgical renal revascularization with an extra-anatomical bypass operation between 1980 and 1992 were reviewed. A total of 175 operations was done in 171 patients, including hepatorenal bypass in 59, splenorenal bypass in 54, iliorenal bypass in 37, thoracic aortorenal bypass in 23, renal autotransplantation in 1 and superior mesentero-renal bypass in 1. There were 5 operative deaths (2.9%) and 7 cases of postoperative graft thrombosis (4%). All patients with poorly controlled hypertension were cured or improved postoperatively. Among patients with ischemic nephropathy, postoperative renal function improved in 35%, remained stable in 47% and deteriorated in 18%. Extra-anatomical techniques remain an important component of the surgical armamentarium for atherosclerotic renal artery stenosis. Thoracic aortorenal bypass is a useful new approach in patients with significant celiac and iliac occlusive disease.

Adult↗
PubMed1995

Treatment of renal cell carcinoma in von Hippel-Lindau disease: a multicenter study.

A total of 65 patients with von Hippel-Lindau disease underwent surgery for renal cell carcinoma (54 bilaterally and 11 unilaterally) at 8 medical centers. Only 1 patient presented with metastatic disease. Radical nephrectomy and nephron sparing surgery were performed in 16 and 49 patients, respectively. Mean posttreatment followup was 68 months. The 5 and 10-year cancer-specific survival rates for all patients were 95% and 77%, respectively. The corresponding rates for patients treated with nephron sparing surgery were 100% and 81%, respectively. Of the latter patients 25 (51%) had postoperative local tumor recurrence but only 2 had concomitant metastatic disease. Survival free of local recurrence was 71% at 5 years but only 15% at 10 years. End stage renal failure occurred in 15 patients (23%): 6 underwent renal transplantation (5 are alive with satisfactory renal function and no evidence of malignancy) and 9 were treated with chronic dialysis (6 are free of tumor). Our results indicate that nephron sparing surgery can provide effective initial treatment for patients with renal cell carcinoma and von Hippel-Lindau disease. These patients must be followed closely, since most will eventually have locally recurrent renal cell carcinoma. When removal of all renal tissue is necessary to achieve control of malignancy, renal transplantation can provide satisfactory replacement therapy for end stage renal disease.

Adolescent↗
PubMed1995

Transperitoneal marsupialization of lymphoceles: a comparison of laparoscopic and open techniques.

This 2-center study compares the relative merits of laparoscopic and open surgical internal marsupialization of pelvic lymphoceles. Laparoscopic lymphocelectomy was performed in 12 patients (group 1). The results were compared with open lymphocelectomy performed in 13 contemporary patients (group 2) as well as 13 historical patients (group 3). Operative time was longer in group 1 compared to groups 2 and 3 (194.6 versus 176.9 versus 133.8 minutes, respectively). However, group 1 had a decreased blood loss (23.1 versus 74.6 versus 61.7 ml.), earlier resumption of oral food intake (0.9 versus 2.5 versus 2.1 days), shorter hospital stay (2 versus 6.1 versus 6.3 days) and abbreviated convalescence (2.2 versus 6.9 versus 4.5 weeks) compared to groups 2 and 3. Complications included cystotomy requiring open repair in 1 patient in group 1, prolonged ileus in 1 in group 2, transection of the ureter of a transplant kidney in 1 in group 3 and pneumonitis in 1 in group 3. Lymphocele recurred in no patient in group 1, 4 in group 2 and 3 in group 3. Mean followup in groups 1 to 3 was 12.8, 25 and 54.5 months, respectively. We conclude that laparoscopic lymphocelectomy is effective, results in minimal patient morbidity and allows for a more rapid recovery compared to open surgical lymphocelectomy.

Adult↗
PubMed1995

Surgical technique and morbidity of elective partial nephrectomy.

Nephron-sparing surgery (NSS) is being increasingly employed for the management of patients with localized renal cell carcinoma (RCC) and a normal opposite kidney. Ideally, such an approach should be reserved for patients in whom the risk of local recurrence and morbidity related to NSS are relatively low. In this article, we will review the technical considerations associated with performing elective partial nephrectomy and discuss the surgical complications specifically related to NSS, with emphasis on prevention, diagnosis, and management. Recent improvements in our technique for performing NSS will be described, and the current data regarding proper patient selection for elective partial nephrectomy will be reviewed.

Acute Kidney Injury↗
PubMed1995

Changing demographics in renal transplant recipients: the 30 year Cleveland Clinic experience.

While it does appear that the most recent era of transplantation has not resulted in significant improvement in long-term allograft function, this appears to be due, at least in part, to the transplantation of increasing numbers of high-risk patients. It is noted that the improved results accomplished over prior eras of transplantation have been maintained despite the inclusion of these high-risk patients. Patients currently undergoing transplantation are more likely to be older, diabetic, obese or African American. All of these subgroups have poorer patient survival in the most recent transplant era and thus, death with a functioning graft has become a significant contributor to graft loss. Recipients were more likely to receive kidneys from cadaveric donors in the most recent era and within the live-donor groups, sibling donation has decreased. Hopefully, the recent trend of increased live-donor transplants (especially living, unrelated transplants) will continue. Cadaveric recipients were at higher risk for posttransplant ATN which, for the first time in the current era, had a significant adverse impact on graft survival. Long-term survival appeared to be associated with particular characteristics (optimal age at transplantation, optimal donor age, live donor, etc.), and can be achieved despite known risk factors, such as rejection or delayed graft function.

Adolescent↗
PubMed1994

Effect of HLA matching on organ distribution among whites and African-Americans.

A total of 159 patients received renal cadaveric grafts under 2 different allocation systems. System 1, a local variance (i.e., a point system different from that of United Network for Organ Sharing [UNOS]), and system 2, the current UNOS point system, differed in the relative emphasis on waiting time and HLA match. The racial composition of the donor pools and recipient waiting lists was the same for both periods examined. The percentage of African-Americans transplanted did not differ significantly under the 2 allocation systems and, in fact, increased slightly, from 29.4% to 33.8%, under system 2, which attributed more weight to HLA match. A difference in the allocation of kidneys from African-American donors was seen. Under system 1, only 2 of 8 kidneys from African-American donors went to African-American recipients, while under system 2, 6 of 8 kidneys from African-American donors went to African-American recipients. These data suggest that the current UNOS point system does not provide any added disadvantage to non-whites and may, in fact, provide an incentive for minority groups to donate organs, in that HLA matching appears to promote intraracial transplantation.

Black People↗
PubMed1994

Epidemiologic and clinical comparison of renal artery stenosis in black patients and white patients.

PURPOSE: This study was undertaken to compare the epidemiologic and clinical features of renal artery stenosis (RAS) in black patients and white patients. METHODS: Data on all patients identified with 50% or greater RAS from 1984 to 1990 were collected and analyzed. The study was conducted at the Cleveland Clinic Foundation, which is a referral center for patients with renal artery disease. Eight hundred nineteen patients with RAS were identified from an institutional registry that records information on patients with this disease. This group comprises 40 black patients (4.9%) and 779 white patients (95.1%). The presence of RAS was determined by abdominal aortography in all patients. Black patients and white patients with RAS were compared with respect to their age, sex, presence and severity of hypertension, renal function, type and extent of renal artery disease, extrarenal vascular disease, and risk factors such as history of smoking, diabetes, and hyperlipidemia. RESULTS: The mean age of black patients and white patients was 62 years; however, a greater proportion of black patients were women (p = 0.01). RAS was due to atherosclerosis in 95% and 92% of blacks and whites, respectively. Although the extent and severity of RAS were equivalent in black patients and white patients, more blacks were diagnosed with severe (p = 0.01) or refractory (p = 0.05) hypertension. Extrarenal vascular disease was present in 95% and 70% of blacks and whites, respectively (p < 0.01). The incidence of coronary artery disease (p < 0.01), cerebrovascular disease (p < 0.01), and peripheral vascular disease (p < 0.01) was greater among black patients. A history of smoking was more common among black patients (p < 0.01). Serum total cholesterol and low-density lipoprotein cholesterol levels were equivalent among black patients and white patients; however, black patients had higher high-density lipoprotein cholesterol (p = 0.03) and lower triglyceride (p < 0.01) levels. CONCLUSIONS: There are significant differences between black patients and white patients with RAS. The basis for these findings and their relationship to the cause and true prevalence of RAS in blacks requires further study.

Adult↗