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Biomedical subjects

R S Pruthi

Publications and source records attributed to R S Pruthi.

At least 19 recordsLinked to original sources
PubMed2000

Prostate-specific antigen.

Serum prostate-specific antigen (PSA) measurements are the most useful serum biomarker to aid in early prostate cancer detection, clinical staging and therapeutic monitoring. Although the optimal use of PSA testing remains controversial, population based studies suggest that PSA screening reduces prostate cancer mortality. Customizing screening protocols based on individual risk factors and PSA level may be a useful approach to reduce overall costs incurred by widespread PSA testing. Lowering PSA cut-offs (i.e., from 4.0 ng/ml to 2.5 ng/ml) may reduce advanced stage prostate cancer, and the use of different PSA derivatives and PSA forms may reduce 'unnecessary' biopsies in some men. In addition to prostate cancer, manipulation and benign diseases of the prostate falsely elevate serum PSA levels. In contemporary clinical practice, PSA testing plays an important role in prostate cancer diagnosis and treatment.

Biomarkers, Tumor↗
PubMed2000

New onset vesicovaginal fistula after transurethral collagen injection in women who underwent cystectomy and orthotopic neobladder creation: presentation and definitive treatment.

PURPOSE: We present our experience with collagen injection for treating urinary incontinence after cystectomy and orthotopic bladder substitution in women. We discuss the efficacy of collagen injection, specific complications and subsequent definitive therapy. MATERIALS AND METHODS: We performed cystectomy and orthotopic bladder substitution in 2 women for muscle invasive transitional cell carcinoma of the bladder. In each case new onset stress urinary incontinence developed after surgery that was refractory to conservative therapy. Intrinsic sphincter deficiency was diagnosed in each patient by video urodynamic studies. Initial treatment involved transurethral collagen injections but subsequent intervention was required due to resultant complications and primary therapy inefficacy. RESULTS: Collagen (3.5 cc per session) was injected in 1 case at 2 treatment sessions and in the other at 3. Incontinence symptoms did not significantly improve in either patient and a new onset vesicovaginal fistula developed 2 days and 1 month after collagen injection, respectively. Subsequently in each case 1-stage transvaginal primary fistula repair was done in multiple layers with a pubovaginal sling procedure. Six months after repair there has been no recurrent fistula and the women remain hypercontinent, requiring intermittent self-catheterization. They are satisfied with their eventual lower tract function and overall outcome. CONCLUSIONS: Collagen injection for type 3 stress urinary incontinence after cystectomy and orthotopic bladder replacement in women may not be as effective and innocuous as in patients with a native bladder. Initial treatment with a pubovaginal sling procedure should be considered.

Aged↗
PubMed1998

Renal masses presenting 25 and 50 years following blunt renal trauma.

The long-term consequences of blunt renal trauma are not well described. We report on 2 patients with a history of blunt renal trauma who presented with radiographically detected renal masses suspicious for renal tumor. Both patients suffered blows to the kidney during boxing matches followed by flank pain and hematuria. The injuries occurred 25 and 50 years prior to the detection of renal masses. Subsequent nephrectomy and histopathological evaluation revealed benign dystrophic renal tissue. These presentations represent probable long-term sequelae of blunt renal trauma.

Aged↗
PubMed1998

The urodynamic relationship of renal pelvic and bladder pressures, and urinary flow rate in rats with congenital vesicoureteral reflux.

PURPOSE: We define the relationship of renal pelvic and bladder pressures with varying urinary flow rates and bladder fullness in unobstructed rats with and without vesicoureteral reflux. MATERIALS AND METHODS: Sprague-Dawley rats (180 to 250 gm.) were evaluated for vesicoureteral reflux followed by simultaneous and continuous renal pelvic and bladder pressure monitoring during bladder filling cycles. RESULTS: The incidence of congenital right vesicoureteral reflux was 25% (14 of 57 rats, below bladder pressure of 40 cm. water). The renal pelvic pressure was significantly higher in rats with reflux compared to normal rats only at very low urine output when the bladder was 90% full or greater and when the urine output was moderate with the bladder 50% full or less. For all other urine outputs and degrees of bladder fullness, there were no significant differences in pelvic pressure between rats with and without reflux. CONCLUSIONS: Renal pelvic pressures in the refluxing and nonrefluxing collecting system of rats with mild to moderate reflux do not differ except under well-defined conditions. Reflux can be induced by raising the intravesical pressure when the urinary flow rate is very low. Furthermore, vesicoureteral reflux pressures decrease post mortem. Therefore, the observation of vesicoureteral reflux is a relative phenomenon defined by urinary flow rate, bladder pressure and in vivo conditions, and one must define the specific bladder pressure and urinary flow rate that are present when reflux occurs. These data help explain why the observation of reflux may be intermittent or transient during various imaging studies.

Animals↗
PubMed1997

Use of serum concentration techniques to enhance early detection of recurrent prostate cancer after radical prostatectomy.

OBJECTIVES: We evaluated the clinical applicability of serum concentration techniques to enhance the detection of prostate-specific antigen (PSA) in men with recurrent prostate cancer after radical prostatectomy. METHODS: We concentrated blood serum by lyophilization and ultrafiltration from female patients who had undergone cystoprostatectomy, "cured" patients who had undergone radical prostatectomy, patients without prostate cancer, and patients with prostate cancer treated with radiation or hormonal therapy. The primary study group consisted of 31 patients with recurrent disease after radical prostatectomy whose initial postoperative PSA fell to undetectable levels (less than 0.07 ng/mL) that later turned positive (0.07 ng/mL or more) by the Tosoh AIA 600 immunoassay run in the ultrasensitive mode. All serum samples of less than 0.07 ng/mL were concentrated by lyophilization or ultrafiltration. RESULTS: Serum concentrated by lyophilization and filtration detected PSA recurrence significantly earlier than did unconcentrated serum in 29 of 31 patients (94%) and in 28 of 31 patients (90%), respectively. The mean advantage for the 29 patients was 362 days; for the 28 patients it was 383 days. The mean native PSA was 0.04 ng/mL (range 0.00 to 0.06) at the time of earliest detection by concentration techniques. Serum from female patients who had undergone cystoprostatectomy and "cured" patients who had undergone radical prostatectomy failed to concentrate, giving a test specificity of 100%. CONCLUSIONS: Serum concentration is a specific and sensitive technique that provides a significant lead time of an additional 12 months in detecting cancer recurrence after radical prostatectomy when compared with nonconcentrated serum. Because the Tosoh assay, when run in the ultrasensitive mode, gave an additional lead time of 9 months at a residual cancer detection limit of 0.07 ng/mL, the combination of the Tosoh assay and serum concentration allows detection of a failed radical prostatectomy about 2 years earlier than does the Hybritech Tandem-R assay, which has a residual cancer detection limit of 0.2 ng/mL.

Aged↗
PubMed1997

New technique of ureteral stent placement for impacted ureteral calculus: the glidewire loop technique.

Impacted ureteral stones pose a challenge during retrograde ureteral stenting. Multiple attempts to bypass the obstruction with conventional guide wires often fail and may result in perforation of the ureter. We describe a new, simple approach to overcome this common problem by utilizing a retrograde glidewire loop technique. The technique described allows safe and successful bypassing and stenting of ureteral obstruction.

Humans↗
PubMed1997

Prostate-specific antigen doubling times in patients who have failed radical prostatectomy: correlation with histologic characteristics of the primary cancer.

OBJECTIVES: This study sought to characterize the postoperative prostate-specific antigen (PSA) doubling time and time to biochemical recurrence in patients who have failed radical prostatectomy. METHODS: Of 539 consecutive patients who underwent radical prostatectomy between 1984 and 1992, postoperative PSA levels in 80 initially became undetectable (less than 0.07 ng/mL) before eventually increasing, as evidenced by rising PSA levels above the residual cancer detection limit of the Tosoh AIA-600 immunoassay run in the ultrasensitive mode (i.e., 0.07 ng/mL or higher). The PSA doubling time and time to biochemical recurrence were calculated for each of the 80 patients and were correlated with the histopathologic variables from the operative specimen. RESULTS: Postoperative PSA doubling times were predicted by the extent of capsular penetration, percent Gleason grade 4 or 5, lymph node involvement, and tumor volume on univariate analysis and by capsular penetration, percent Gleason grade 4 or 5, lymph node involvement, and patient age on multivariate analysis. Times to recurrence were predicted by the presence of positive margins and percent Gleason grade 4 or 5 in both univariate and multivariate regression models. The PSA doubling time did not correlate with recurrence time. The median PSA doubling time for all patients was 284 days, and the median time to recurrence was 648 days. CONCLUSIONS: These results demonstrate that PSA doubling time and recurrence time are indicative of different biologic characteristics of recurrent prostate cancer: Doubling time appears to represent the aggressiveness of the original prostate cancer, whereas time to recurrence reflects the extent of residual postoperative disease. This information should aid in the selection of men who need greater vigilance during postoperative surveillance.

Adult↗
PubMed1997

The use of renal parenchymal area in children with high grade vesicoureteral reflux.

PURPOSE: We sought to apply 2-dimensional sonographic measurements of renal parenchymal area in children with high grade vesicoureteral reflux to assess reliability and accuracy in estimating differential renal function, and in predicting clinical outcome compared to traditional 1-dimensional sonographic measurements. MATERIALS AND METHODS: We retrospectively evaluated 121 sonograms from 30 patients with a grade 4 or 5 primary vesicoureteral reflux, including 14 who underwent ureteral reimplantation during followup and 16 who were followed on prophylactic antibiotic therapy. One-dimensional sonographic measurements of longitudinal length and bipolar thickness were determined in refluxing and contralateral kidneys, as were 2-dimensional measurements of longitudinal parenchymal area using computer planimetry. Renal length, bipolar thickness and parenchymal area were compared to renal function data determined by nuclear renography. Renal length and area was also represented as a percent of age adjusted normal values using previously published nomograms. RESULTS: Differential renal function correlated well with differential parenchymal area for all patients (r = 0.924). This correlation persisted in patients with (r = 0.917) and without scarring (r = 0.890), as determined by dimercapto-succinic acid scan. Differential length did not correlate as well (r = 0.661) and bipolar parenchymal thickness did not correlate at all (r = 0.021). Sonographic age adjusted area of the refluxing kidneys was approximately two-third normal. No statistically significant difference was observed among age adjusted renal area of the observation, preoperative and postoperative groups. Contralateral kidney area was not significantly different than normal. CONCLUSIONS: Our data indicate that serial sonographic measurements of longitudinal renal parenchymal area provide a simple and accurate method of monitoring renal growth and function in patients with high grade vesicoureteral reflux. In contrast to 1-dimensional measurements of renal length and bipolar parenchymal thickness, renal parenchymal area correlates well with renal function. Area also appears to be a more sensitive method of monitoring renal growth in children with vesicoureteral reflux.

Child, Preschool↗
PubMed1997

An unusual complication following uroflowmetry: water intoxication resulting in hyponatremia and seizure.

Uroflowmetry is considered a simple and noninvasive test in the evaluation of urinary symptoms. It requires patients to consume fluid orally for a full bladder prior to undertaking the test. Guidelines regarding the amount and rate of oral fluid intake have not been accurately defined. We report on a patient who suffered a serious complication of water intoxication with hyponatremia and seizure due to excessive water consumption and absorption during uroflowmetry. We discuss the underlying factors concerning this complication and recommend a more conservative approach to attain a full bladder in a certain subgroup of patients at risk of developing such a complication.

Adult↗
PubMed1996

Pediatric genitourinary tumors.

Each year significant advances are made in the clinical evaluation and treatment of genitourinary tumors in children as well as in the understanding of the molecular biology of tumorigenesis and genetics. In addition, the long-term outcome and complications of current treatments are now becoming available for review. The purpose of this article is to review recent literature on pediatric genitourinary Wilms' tumor, rhabdomyosarcoma, and testicular carcinoma in situ.

Adolescent↗
PubMed1993

Secretin receptors in a new preparation of plasma membranes from intrahepatic biliary epithelium.

Secretin is thought to cause choleresis by acting on a receptor expressed by bile duct epithelial cells. In this study, the receptor was characterized using a new preparation of intrahepatic bile duct plasma membranes. Hyperplastic biliary trees were obtained from 3-week bile duct-ligated rats. The biliary trees were homogenized, filtered, and subjected to an aqueous two-phase partition technique to yield highly purified plasma membranes (confirmed by a 14-fold enrichment in gamma-glutamyl transpeptidase activity and a 10-fold enrichment in 125I-secretin binding). 125I-secretin bound saturably with high affinity and in a dose-dependent fashion (Kd = 1.3 +/- 0.1 nM, Bmax = 273 +/- 23 fmole/mg) to purified plasma membranes. The binding characteristics of secretin were most consistent with a single site receptor model. Competitive binding studies indicated that the secretin-related peptides glucagon, peptide histidine isoleucine, gastric inhibitory peptide, and growth hormone releasing factor did not inhibit binding. Vasoactive intestinal peptide (1 microM) reduced maximal binding by 19 +/- 1%. The GTP analogs guanylylimidodiphosphate and guanosine 5'-O-[3-thiotriphosphate] (1 microM) inhibited binding by 16 +/- 2 and 13 +/- 1%, respectively. In conclusion, secretin binds to a specific, high-affinity receptor in intrahepatic bile duct epithelium that is coupled to a G-protein-linked signal transduction system.

Animals↗
PubMed1993

The effect of octreotide on hepatic regeneration in rats.

The effect of the long-acting somatostatin analog octreotide on liver regeneration was studied in rats in vitro and in vivo. The effect of continuous subcutaneous octreotide infusion on regenerative liver weight and relative DNA synthesis was examined in rats that had undergone 70% hepatectomy. Administration of octreotide resulted in a 33% reduction of regenerating liver weight at 72 hours and a 67% reduction of regenerative hepatocellular hyperplasia at 24 hours. This effect was reversed within 12 hours after withdrawal of the drug. The mechanism for the inhibitory effect of octreotide appears to be indirect, because experiments in hepatocyte cultures did not demonstrate a direct inhibitory effect on serum-free or epidermal growth factor-induced regenerative hepatocyte proliferation. Because insulin levels were suppressed by octreotide in the in vivo experiments, suppression of hepatotrophs may be the mechanism by which octreotide inhibits liver regeneration.

Animals↗