Search PubMed⌕ Search

Biomedical subjects

H S Clarke

Publications and source records attributed to H S Clarke.

15 recordsLinked to original sources
PubMed2001

Gunshot wounds to the ureter: a 40-year experience at Grady Memorial Hospital.

PURPOSE: Because of the morbidity associated with missed ureteral injuries, a high index of suspicion must be present to diagnose this type of injury. We reviewed our 40 years of trauma experience at Grady Memorial Hospital. MATERIALS AND METHODS: We retrospectively reviewed the records of 118 patients with ureteral injuries secondary to a gunshot wound to the ureter from 1960 to 1999. All cases were reviewed for the mechanism of injury, location, initial urinalysis, imaging modalities, associated injuries, operative procedures and complications. RESULTS: Our population consisted of patients 14 to 71 years old, of whom 66 had right ureteral, 51 had left ureteral and 1 had bilateral injury. Urinalysis revealed no evidence of blood in the urine in 15% of the patients in whom the test was performed. Excretory urography had a false-negative rate of 33%. The injury was located at the proximal, mid and distal ureter in 43, 38 and 37 cases, respectively. Multiple surgical approaches were used depending on the location and severity of the defect. Only 1 patient had an isolated ureteral injury, while the remainder had associated injuries. Complications were present in 24 cases. CONCLUSIONS: To our knowledge this series of ureteral injuries is the largest reported to date. Because preoperative urinalysis and imaging studies are unreliable for ruling out injury, a high index of suspicion must be present. Furthermore, a predefined trauma protocol, as defined in our algorithm, decreases the number of missed ureteral injuries that may potentially complicate the outcome of an already critical case.

Adolescent↗
PubMed1998

Evaluation of staging lymphadenectomy in prostate cancer.

OBJECTIVES: To prospectively evaluate a clinical algorithm that predicts nodal status in patients with prostate cancer and to assess the impact on the outcome. METHODS: Between September 1988 and December 1994, 192 patients with organ-confined prostate cancer and considered surgical candidates for radical perineal prostatectomy (RPP) were stratified using the algorithm: prostate-specific antigen (PSA) 20 ng/mL or less, Gleason score 7 or lower, and clinical Stage T2a or lower. Patients failing any of these criteria were placed in the high-risk group and underwent a pelvic lymphadenectomy. Patients who satisfied all the criteria were placed in the low-risk group and underwent RPP without evaluation of the pelvic lymph nodes. Another contemporaneous cohort of patients (n = 65) underwent pelvic lymphadenectomy and radical retropubic prostatectomy (RRP) without use of the algorithm and were used as a control group. Patients were monitored for at least 24 months. RESULTS: In the RPP group, 177 patients were considered low risk according to the algorithm and were not offered staging lymphadenectomy before surgery, whereas 15 patients were categorized as high risk for metastasis and underwent staging lymphadenectomy. In the RRP and lymphadenectomy group, 41 patients were considered at low risk and 24 at high risk of disease spread according to the algorithm. In the RPP group, low-risk patients (no lymphadenectomy) had a PSA recurrence rate (27%) similar to that of low-risk patients in the RRP group with negative lymph nodes (29%), P = 0.8. Similarly, high-risk patients with negative lymph nodes in both groups had a similar recurrence rate (53% for RPP and 50% for RRP). Univariate logistic regression analysis showed that PSA was the most significant predictor for disease recurrence (P = 0.0004) followed by preoperative Gleason scores (P = 0.02) and clinical stages (P = 0.03). Multivariate stepwise analysis demonstrated that Gleason score and clinical stage did not add to the prediction of recurrence over PSA alone. CONCLUSIONS: Staging lymphadenectomy can be omitted in low-risk patients without deleterious effects on the outcome as measured by PSA recurrence.

Aged↗
PubMed1998

Two cases of vasculitis of the urinary bladder: diagnostic and pathogenetic considerations.

BACKGROUND: Vasculitis involving the urinary bladder is rare and difficult to diagnose. Organ-isolated vasculitis challenges pathogenetic theories. METHODS AND RESULTS: A human immunodeficiency virus- and hepatitis B virus-infected man with hematuria and a mass lesion was initially given a clinicopathologic diagnosis of bladder hamartoma. Over 11 months, without immunosuppressive therapy, there were multiple "recurrences" of the tumor with progressive distal ureteral obstruction, but no evidence of systemic vasculitis. Polyarteritis nodosa-like vasculitis with positive immunostaining for hepatitis B surface antigen in urothelium and vessels was found on review. A second patient, presenting with signs and symptoms suggesting transitional cell carcinoma in situ, was found to have small vessel vasculitis. CONCLUSIONS: Bladder vasculitis should be considered in the differential diagnosis of neoplasia. Extrahepatic hepatitis B virus infection may be related to the organ specificity in some cases of vasculitis.

Adult↗
PubMed1997

Benign prostatic hyperplasia.

Benign prostatic hyperplasia is a common and costly disease that affects older men. This article reviews the underlying histopathologic changes that cause benign prostatic hyperplasia. The symptoms and systematic evaluation of the patient are described, along with the current therapeutic options for treatment.

Adrenergic alpha-Antagonists↗
PubMed1995

Intravesical suramin in the prevention of transitional cell carcinoma.

OBJECTIVES: To examine the effects of intravesical suramin on N-methyl-N-nitrosurea (MNU)-induced bladder tumors in Fischer 344 rats. METHODS: Multiple cohorts of female rats received four biweekly intravesical instillations of MNU. A control group received no other treatment, the experimental group received 25 mg/kg intravesical suramin twice a week beginning at week 6. RESULTS: After 18 weeks from the first instillation of MNU, 60% to 65% of control animals developed papillary transitional cell carcinoma, compared with only 0% to 10% of the suramin-treated animals (P = 0.01 to P = 0.0007). There was no local or systemic toxicity observed. CONCLUSIONS: Intravesical suramin is an effective chemopreventative therapy for transitional cell carcinoma in vivo with minimal toxicity.

Administration, Intravesical↗
PubMed1993

The hyponatremia of neonatal urinary ascites: clinical observations, experimental confirmation and proposed mechanism.

A case of neonatal urinary ascites with severe hyponatremia is reported. Critical review of the literature on neonatal urinary ascites, which included determination of serum electrolytes, revealed a 70% incidence of hyponatremia. In an attempt to explain the mechanism of the hyponatremia, urinary ascites was produced in rats by creation of either a unilateral (uretero-peritoneal) or bilateral (vesicoperitoneal) shunt. Hyponatremia did not occur in the unilateral group but it was profound in the bilateral group. At 48 hours postoperatively renin was unchanged in the unilateral group but it was significantly elevated in the bilateral group. Aldosterone was elevated in the unilateral group and markedly elevated in the bilateral group. Urine entering the peritoneal cavity equilibrates with plasma. The proposed mechanism of hyponatremia in the bilateral group is autodialysis with intraperitoneal urine containing progressively lower sodium concentration secondary to increased renin and aldosterone.

Aldosterone↗
PubMed1987

Captopril renography in two kidney and one kidney Goldblatt hypertension in dogs.

In order to improve on the technique of noninvasive detection of renal artery stenosis, we studied the effects of angiotensin converting enzyme inhibition with captopril on individual kidney hemodynamics and function as assessed by technetium-99m diethylenetriaminepentaacetic acid [( 99mTc]DTPA) renal flow studies and iodine-131 orthoiodohippurate [( 131I]hippuran) renography in experimental Goldblatt's hypertension. In two-kidney, one-clip (renin-dependent) hypertension, captopril (1.5 mg/kg bolus with 1.5 mg/min infusion) reduced mean arterial pressure (MAP) and ipsilateral glomerular filtration rate (GFR) without changes in the contralateral kidney. Captopril infusion resulted in alterations in both the [99mTc]DTPA and [131I]hippuran studies, which were most evident in the 15-min [99mTc]DTPA renal flow studies. In one-kidney, one-clip (volume-dependent) hypertension, captopril reduced MAP but did not alter GFR, renal plasma flow, or the radionuclide studies. These studies suggest that the [99mTc]DTPA renal flow study coupled with captopril challenge may unmask intrarenal angiotensin II-dependent functional and hemodynamic changes of the stenotic kidney, and offers promise in the detection of renin-dependent hypertension.

Animals↗
PubMed1986

Effect of captopril on 99mTc-diethylenetriaminepentaacetic acid renograms in two-kidney, one clip hypertension.

In an effort to improve on the noninvasive detection of renal artery stenosis, we investigated the effect of angiotensin converting enzyme inhibition on computer-assisted 99mTc-diethylenetriaminepentaacetic acid (DTPA) renal flow studies in a canine model of two-kidney, one clip hypertension and compared these findings with clearances of inulin and p-aminohippuric acid in the stenotic and contralateral kidney before and after converting enzyme inhibition. The 99mTc-DTPA renal flow study with the converting enzyme inhibitor captopril (1.5 mg/kg bolus with 1.5 mg/min infusion) showed an increased sensitivity in the detection of unilateral renal artery stenosis over the use of the 99mTc-DTPA study alone. Captopril induced striking alterations that were most evident in the 15-minute 99mTc-DTPA renal flow study, in which all nine curves exhibited severely blunted uptake and excretion of the radionuclide. These changes were reversed during a recovery study without converting enzyme inhibition and were not seen when blood pressure was lowered with nitroprusside to a level similar to that observed during converting enzyme inhibition. The changes shown by the 99mTc-DTPA study during converting enzyme inhibition correlated with a decrease in the glomerular filtration rate of the stenotic kidney. Captopril infusion significantly decreased the glomerular filtration rate of the stenotic kidney (16.0 +/- 3.1 vs 11.0 +/- 2.5 mg/min, p less than 0.03) but not of the contralateral kidney (32.4 +/- 2.6 vs 28.4 +/- 2.8 mg/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Technetium-99m DTPA renal flow studies in Goldblatt hypertension.

Computer-assisted dynamic renal studies were performed on a group of 14 mongrel dogs before and after the induction of unilateral renal artery stenosis. Ninety-second technetium-99m diethylenetriaminepentaacetic acid ( [99mTc]DTPA), 15-min [99mTc]DTPA, and 30-min iodine-131 orthoiodohippurate ( [131I]hippuran) time-activity curves were analyzed and correlated with reduction of renal blood flow as measured by electromagnetic flow probe and PAH clearance techniques. Parameters of the 90-sec [99mTc]DTPA curves found to be significantly different for the same kidney before and after stenosis were: upslope, curve width at 75% maximum, maximum activity value, and differential (stenotic/contralateral) maximum activity ratio. For blood flow reductions greater than 33%, the [99mTc]DTPA studies were judged diagnostic of unilateral renal artery stenosis in all cases, whereas the [131I]hippuran time-activity curves were indicative of stenosis in only six of ten studies. Thus, in this model we find the computer-assisted 90-sec [99mTc]DTPA renal flow study to be superior to conventional [131I]hippuran renography in the diagnosis of moderate-to-severe unilateral renal artery stenosis.

Animals↗
PubMed1985

Improved computer-assisted nuclear imaging in renovascular hypertension.

Computer-assisted dynamic renal studies using both the 90 second 99mTc-DTPA and the conventional 30 minute 131I-Hippuran methods were performed in nine patients with angiographically proven renal artery stenosis. Time activity curves for both studies were derived from regions of interest selected from the computer-acquired dynamic images. The following parameters were used to assess renal blood flow: differential maximum activity, minimum/maximum activity ratio, and peak width. The computer-assisted DTPA study accurately predicted (9/9) the stenotic side documented angiographically, whereas the conventional Hippuran scan was clearly predictive in only 57% (5/9). The best discriminatory factors for the 90 second 99mTc-DTPA scan, when compared to a normal template synthesized from curves obtained from normal subjects (20), were differential maximum activity and peak width. In conclusion, the computer-assisted 90 second 99mTc-DTPA renal blood flow scan was superior to the conventional 30 minute 131I-Hippuran scan in demonstrating unilateral renovascular disease. The DTPA study was highly predictive of the angiographic findings, and this noninvasive study may prove useful in the diagnosis and serial evaluation following surgery or angioplasty in patients having renal artery stenosis.

Adult↗
PubMedDate not supplied

A study of resistive indices in the arcuate arteries of the kidney over the course of gestation.

OBJECTIVE: Our purpose was to assess whether there was a variation in the resistive index (RI) of the arcuate artery in the kidneys of patients with hydronephrosis in pregnancy. STUDY DESIGN: Forty-seven patients were studied to establish norms for the RI of the arcuate arteries in pregnancy, and these measurements were correlated with the development of hydronephrosis over the course of gestation. RESULTS AND CONCLUSIONS: The RIs were noted to remain unchanged from the nonpregnant state throughout gestation. They were also unchanged by the presence of the physiologic hydronephrosis of pregnancy.

Adult↗