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Biomedical subjects

W A See

Publications and source records attributed to W A See.

At least 19 recordsLinked to original sources
PubMed2006

Are bone scans necessary in men with low prostate specific antigen levels following localized therapy?

PURPOSE: The prostate specific antigen level at which to recommend a bone scan after treatment of early prostate cancer is controversial. We identified the incidence of bone metastases at varying prostate specific antigen levels in asymptomatic men following radical prostatectomy, radiation therapy and watchful waiting. MATERIALS AND METHODS: Data were obtained from the Early Prostate Cancer trial comparing placebo with bicalutamide in addition to standard care for localized prostate cancer. As part of the trial patients were required to have routine bone scans regardless of prostate specific antigen levels. The prostate specific antigen levels were divided into subgroups and the incidence of positive bone scans was calculated for each group. RESULTS: The incidence of positive bone scans in patients treated with watchful waiting and given bicalutamide or placebo was low (0.7% to 3.2%) at prostate specific antigen levels less than 20 ng/ml. At greater than this level the sample sizes were smaller but there was a significant increase in the incidence of positive bone scans. In the groups treated with radiation therapy or radical prostatectomy, regardless of the addition of bicalutamide, the incidence of positive bone scans was low (0.2% to 1.4%) at prostate specific antigen levels less than 5 ng/ml. The sample sizes were smaller at prostate specific antigen levels greater than 5 ng/ml so the results are harder to interpret. CONCLUSIONS: Bone scans can be confidently eliminated in the followup of patients with early prostate cancer after standard care of those with prostate specific antigen levels less than 5 ng/ml. This level can be increased to 20 ng/ml with caution in those patients treated with watchful waiting.

Androgen Antagonists↗
PubMed2001

Phase II trial of GM-CSF in advanced prostate cancer.

OBJECTIVES: Prostate-specific antigen only disease progression following definitive therapy is significant therapeutic dilemma. The benefit of hormonal therapy remains unproven and is associated with significant toxicity, more pronounced with chronic use. Biochemical progression following hormonal therapy has no standard treatment. New approaches to the management of this subset of patients are needed. A previous study in advanced prostate cancer demonstrated biologic activity of granulocyte macrophage-colony stimulating factor. The purpose of this study was to evaluate the activity of granulocyte macrophage-colony stimulating factor in a less heavily pretreated population. MATERIALS AND METHODS: Sixteen patients with advanced prostate cancer, 7 hormonally naïve, and 9 androgen independent, were treated with granulocyte macrophage-colony stimulating factor administered subcutaneously at 250 microg three times a week for up to 6 months. Prostate-specific antigen measurements were obtained every 2 weeks. RESULTS: No patient achieved an objective response. Six patients demonstrated a 10-15% decline in their baseline prostate-specific antigen which was maintained during the entire treatment period. Five of these 6 patients demonstrated a rise in their prostate-specific antigen following study completion. Therapy was well tolerated, with only 1 grade 3 event which was not treatment-related. CONCLUSIONS: Granulocyte macrophage-colony stimulating factor demonstrates modest biologic evidence of activity in prostate cancer as manifested by prostate-specific antigen response. Further investigation of the mechanism of activity and additional clinical evaluation of this agent seems warranted.

Adenocarcinoma↗
PubMed2001

Evaluation of gene transfer efficiency by viral vectors to murine bladder epithelium.

PURPOSE: In pre-clinical gene therapy studies of bladder cancer there is tremendous variation in the ability of viral vectors to deliver genetic material to bladder epithelium. Possible explanations for this variability may involve the physical parameters of delivering vectors in these experimental models. We examined the effects of intravesical volume and pressure during instillation as well as chemical modification of the bladder epithelium on subsequent gene expression in the bladder in mice. MATERIALS AND METHODS: Female C57B1/6 mice underwent intravesical instillation of the replication restricted canarypox virus (ALVAC) recombinant for the reporter genes luciferase or beta-galactosidase. Similar viral titers were instilled at different volumes and a pressure transducer measured intravesical pressure when the vector was instilled. Also, various agents, including 0.6 N hydrochloric acid, 0.4% oxychlorosene, poly-L-lysine and 0.25 M. ammonium chloride, were used to modify the bladder surface before vector instillation and then assayed for transgene expression. RESULTS: As expected, maximum intravesical pressure measured during instillation was significantly greater in mice instilled with a higher volume (33.1 versus 9.8 mm. Hg). Significantly more gene expression was detected in bladders instilled with a higher volume of viral vectors (p <0.05). Likewise, higher instillation pressures resulted in higher transgene expression in distant organs. Modification of the bladder epithelium with agents such as oxychlorosene and poly-L-lysine resulted in elevated gene expression with only minimal increases in systemic activity. CONCLUSIONS: Significant differences in gene expression are achieved by varying physical parameters during intravesical instillation. Increased gene expression associated with larger volume instillation may be responsible for some reported variability of gene transfer to the bladder. Alternate manipulations, such as modifying the bladder surface, may be done to enhance gene transfer to the urothelium without increasing systemic distribution.

Animals↗
PubMed2000

Continuous antegrade infusion of adriamycin as adjuvant therapy for upper tract urothelial malignancies.

OBJECTIVES: To evaluate the feasibility, efficacy, and toxicity of antegrade chemotherapy delivered continuously as adjuvant treatment for patients with upper tract transitional cell carcinoma. METHODS: During a 6-year interval, 12 patients with upper tract transitional cell malignancies underwent continuous antegrade intraluminal infusion chemotherapy (CAIIC) with adriamycin. After placement of percutaneous access and surgical treatment of the primary lesion, patients received 5-day cycles of CAIIC. Patients received between two and four treatment cycles at 2-week intervals. After therapy, patients with no evidence of residual disease were then monitored long-term with retrograde pyelography and upper tract cytology. RESULTS: Twelve patients underwent a total of 35 5-day cycles of CAIIC. No patient experienced hematologic and/or local/regional toxicity during or after drug infusion. Three patients were treated for upper tract carcinoma in situ, and 9 patients had discrete exophytic tumors. Two patients died (treatment unrelated) before a final assessment of therapeutic outcome, leaving 10 patients available for evaluation of the therapeutic response. One patient with carcinoma in situ and 5 of 7 patients with discrete upper tract tumors remained disease free after surgery and adjuvant therapy. Both patients with discrete tumors in whom therapy failed had residual gross disease after primary surgical treatment. CONCLUSIONS: CAIIC using adriamycin was well tolerated for periods of up to 5 days over multiple cycles. Early data suggest a limited efficacy in treating patients with gross residual disease. The efficacy of this approach in preventing the recurrence of upper tract disease after surgical ablation awaits further assessment.

Aged↗
PubMed2000

Tea consumption and risk of bladder and kidney cancers in a population-based case-control study.

Recent epidemiologic studies have suggested that tea may be protective against cancers of the urinary tract. The authors examined the association between usual adult tea consumption and risk of bladder and kidney cancers in a population-based case-control study that included 1,452 bladder cancer cases, 406 kidney cancer cases, and 2,434 controls. For bladder cancer, the age- and sex-adjusted odds ratios (OR) (95% confidence intervals (CI)) referent to nonusers of tea were 0.9 (0.7, 1.1) for <1.0 cup/day, 1.0 (0.8, 1.2) for 1.0-2.6 cups/day, and 0.9 (0.7, 1.1) for >2.6 cups/day (cutpoints for users based on the tertile distribution among controls). When more extreme cutpoints were used, persons who consumed >5 cups/day (>90th percentile) had a suggestive decreased risk (OR = 0.7; 95% CI 0.5, 1.0), but there was no evidence of a dose-response relation. In analyses stratified by median total beverage intake (2.6 liters/day), there was an inverse association with tea use among persons who consumed less than the median (OR = 0.5; 95% CI 0.3, 0.8) but no association for persons who consumed at or above the median. In contrast, for kidney cancer, there was no association with tea use. Adjustment for site-specific risk factors did not alter these results. This study offers only minimal support for an inverse association between tea consumption and bladder or kidney cancer risk.

Adult↗
PubMed2000

Distal ureteral regeneration after radical transurethral bladder tumor resection.

OBJECTIVES: Radical, full-thickness resection of the bladder wall and overlying bladder tumor is a management option in highly selected patients with muscle invasive bladder cancer. The consequences of iatrogenic ureteral injury in patients whose tumor involves the ureteral orifice and intramural ureter have not been reported. This report details an experience with 4 patients who underwent full-thickness resection of the hemi-trigone and distal ureter as treatment for muscle-invasive bladder tumors. METHODS: Between August 1995 and February 1999, 4 patients with T2 transitional cell cancer involving the bladder base and hemi-trigone underwent radical transurethral resection of bladder tumor (TURBT), defined as resection of the tumor and bladder wall into the perivesical fat as primary tumor management. Six weeks later, the patients underwent a restaging TURBT to assess the pathologic response and status of the distal ureter. Patients were then followed up at regular intervals for the development of hydronephrosis and/or upper tract complications. RESULTS: Regeneration of the distal ureter was noted at 6 weeks in all patients. At a mean follow-up of 24 months, no patient had developed evidence of upper tract deterioration. All patients remained without evidence of tumor recurrence. CONCLUSIONS: This experience suggests that iatrogenic injury to the distal ureter during radical transurethral resection of tumor involving the hemi-trigone does not result in long-term distal ureteral damage. Involvement of the hemi-trigone by tumor does not appear to be a contraindication to radical TURBT.

Aged↗
PubMed2000

Biomarker distribution after injection into the canine prostate: implications for gene therapy.

OBJECTIVE: To evaluate the distribution of biomarkers after transrectal injection into the canine prostate and to report a method for enhancing the distribution of gene expression. MATERIALS AND METHODS: Carbon black was first used to evaluate the histopathological distribution in canine prostate of single or multiple injections via the transurethral, transperineal and transrectal routes. The distribution of canarypox virus (ALVAC) vector-delivered gene expression was then compared using both fluid-phase injection techniques and delivery in a solid carrier composed of a gelatine sponge matrix. RESULTS: After transurethral administration, carbon black was detected as scattered particles in ducts and acini, mostly in the periphery of the gland. Direct transrectal injection of carbon black resulted in a localized collection at the site of injection, with only a minimal peri-acinar distribution. Transrectal injection of the fluid-phase (virus suspended in diluent) ALVAC vector encoding the beta-galactosidase gene resulted in a similar distribution, with limited gene expression at the site of injection and in the needle track. Delivery of the same number of virus particles in the gelatine sponge matrix resulted in qualitatively greater gene expression. CONCLUSIONS: Direct injection of the canine prostate with biomarkers, including viral vectors, in the fluid-phase results in very localized gene expression, while the distribution was more widespread after delivery in a gelatine sponge matrix.

Animals↗
PubMed2000

Autocrine IL-6 production by human transitional carcinoma cells upregulates expression of the alpha5beta1 firbonectin receptor.

PURPOSE: Studies have demonstrated elevated expression and secretion of IL-6 by transitional cell carcinomas (TCC) following bacillus Calmette-Guerin (BCG) therapy. At present, the role of IL-6 on the biology of TCC is poorly understood. This study evaluated the influence of IL-6 expression on a critical variable regulating BCG-tumor interaction, the tumor expression of alpha5beta1 integrin. MATERIALS AND METHODS: A human TCC cell line (253J) was transfected with an expression vector containing the full-length IL-6 cDNA sequence. Overexpression of IL-6 mRNA and protein was confirmed by Northern analysis and ELISA, respectively. Clones found to overexpress IL-6 were then assayed for alpha5beta1 expression using Northern analysis and flow cytometry. The effect of alterations in alpha5beta1 expression on tumor adherence to fibronectin (FN), and BCG adherence to tumor cells was determined using specific adherence assays. RESULTS: mRNAs for both the alpha5 and beta1 subunits of the FN receptor were increased an average of 9.4 fold and 125.7 fold respectively in the IL-6 overexpressing transfectants relative to the parental 253J cells. Increased mRNA of alpha5 and beta1 was associated with increased cell surface expression of both proteins. Increased protein expression resulted in greater FN substrate binding affinity and increased adherence of BCG to tumor cells. CONCLUSIONS: Autocrine expression of IL-6 upregulates the expression of FN receptor subunits in TCC. Increased alpha5beta1 expression increases cellular adherence to FN, and BCG adherence to tumor cells. These results suggest a role for IL-6 in mediating the antitumor activity of BCG by influencing BCG's adherence to TCC.

Autocrine Communication↗
PubMed1999

Phase II trial of suramin in patients with metastatic renal cell carcinoma.

This study was conducted to assess the efficacy and toxicity of suramin administered using a fixed dose schedule in patients with advanced renal cell carcinoma. Fourteen eligible patients with advanced renal cell carcinoma were enrolled and treated on a fixed dose schedule of suramin administered over 12 weeks. Suramin was administered by intravenous infusions over 1 hour. None of the 13 evaluable patients demonstrated an objective response. Only 3 patients completed the 12-week therapy course, with the majority developing progressive disease on therapy. The fixed dosage schedule was well tolerated with minimal to moderate toxicity. Suramin in this fixed dose schedule is well tolerated but has no activity in advanced renal cell carcinoma.

Adult↗
PubMed1999

Laparoscopic practice patterns among North American urologists 5 years after formal training.

PURPOSE: We assessed urologist laparoscopy practice patterns 5 years after a postgraduate training course in urological laparoscopic surgery. Results were compared to findings from similar studies performed on the same cohort at 3 and 12 months after training. MATERIALS AND METHODS: Between January 1991 and November 1992, 11, 2-day university sponsored, postgraduate laparoscopic surgery training programs were held. A survey was mailed to the 322 North American participants in the summer of 1997 to determine current laparoscopic use and experience. RESULTS: Of the 166 respondents (51% response rate) 53.6% (89) had performed 1 or more laparoscopic procedures in the previous year, compared to 84% 1 year following course completion. Of the respondents 37% believed their laparoscopic experience was sufficient to maintain skills compared to 66% at 1 year. Of the respondents 6% had performed more laparoscopic procedures while 82% had performed fewer than anticipated. Reasons cited for decreased use included decreasing and/or lack of indications, increased cost, decreased patient interest, higher complication rates, decreased institutional support and increased operative time. Respondents practicing in academic or residency affiliated centers, or those who had completed residency after 1980 were more likely to have performed more procedures than anticipated (p = 0.044) compared to community based colleagues. CONCLUSIONS: Laparoscopic use by urologists trained in the postgraduate setting is decreasing. Few respondents are maintaining the skills acquired during the original training course. Decreased use appears to be multifactorial.

Humans↗
PubMed1998

Stable overexpression of TGFbeta1 in a transitional carcinoma cell line: impact on fibronectin production.

INTRODUCTION: TGFbeta1 is a potent modulator of the biology of both benign and neoplastic cells. Exocrine TGFbeta1 has been shown to alter fibronectin expression of bladder carcinoma cell lines. The present study describes the development of a stable TGFbeta1 overexpressing transitional carcinoma cell line, and evaluates the impact of autocrine TGFbeta1 production on fibronectin expression. MATERIALS AND METHODS: The human transitional carcinoma cell line 253J was transfected using the pcDNA3/hTGFbeta1 expression vector under control of the CMV promoter. TGFbeta1 mRNA expression was determined by Northern analysis. TGFbeta1 protein levels were analyzed by biological assay. Subsequently, the effect of TGFbeta1 autocrine production on fibronectin expression at both the mRNA and protein level was determined. Results were compared to cells transfected with the pcDNA3/CAT and non-transfected 253J cells. RESULTS: Two 253J clones which uniformly expressed TGFbeta1 mRNA at 22 and four-fold increases relative to controls were identified. mRNA overexpression correlated with marked increase in biologically active TGFbeta1 protein production. Autocrine production of cellular TGFbeta1 showed a positive correlation with fibronectin expression at both the mRNA and protein levels. CONCLUSIONS: Autocrine expression of TGFbeta1 increases cellular fibronectin production in a human transitional carcinoma cell line. Therapeutic strategies altering urothelial production of TGFbeta1 and fibronectin may be a potential strategy to potentiate intravesical BCG activity.

Carcinoma, Transitional Cell↗
PubMed1998

Alterations in constituent urinary proteins in response to bladder outlet obstruction in rats.

PURPOSE: Benign prostatic hyperplasia, resulting in bladder outflow obstruction, induces well recognized clinical symptoms and morphologic bladder changes. Despite these phenomenon, relatively little is known with regard to the precise molecular events occurring in the bladder as a consequence of obstruction. In an effort to screen for alterations in bladder gene expression induced by obstruction, and/or alterations in uroepithelial integrity, this study compared pre- and post-obstructive constituent urinary proteins in an animal model. MATERIALS AND METHODS: Outlet obstruction was created using a previously established model system. Experimental animals were surgically obstructed for either 2 or 7 days, at which time the urine was aspirated and the bladders removed and weighed. Urinary proteins were separated using 2-D PAGE. Following comparison of sham versus experimental animals, microsequencing was performed on proteins that were down regulated. RESULTS: Duplicate experiments confirmed the presence of outflow obstruction. Statistically significant increases (p <0.01) in bladder weights were seen at 2 and 7 days in the obstructed groups as compared with both sham and control groups. 2-D PAGE demonstrated a down regulation of three urinary proteins post-obstruction. Microsequencing identified these proteins as prostatic steroid-binding protein C3 precursor (pI=5.5, MW=15000), glandular kallikrein 9 (S3) precursor (pI=6.2, MW=19000), and glandular kallikrein 8 (P1) precursor (pI=6.2, MW=33000). CONCLUSIONS: Bladder outflow obstruction alters constituent urinary protein composition in an animal model system. The precise etiology of these alterations remains to be defined.

Androgen-Binding Protein↗
PubMed1997

Continuous infusion, intravesical doxorubicin for the treatment of regionally advanced bladder cancer: a phase I-II trial.

Patients with regionally advanced bladder cancer not considered candidates for definitive surgical intervention underwent continuous antegrade infusion of doxorubicin by percutaneous nephrostomy tube. Doxorubicin was administered for 7 consecutive days at a rate designed to achieve target urinary concentrations (range 5-80 micrograms/ml). Urine and serum concentrations of doxorubicin were monitored daily. Toxicity was assessed by serial renal scans, antegrade nephrostograms, blood counts, and serum chemistries. Patients were restaged after three cycles of therapy. In all, 23 cycles, constituting 156 days of therapy, were administered to 10 patients. Target urinary drug levels were achieved during all cycles. Total doxorubicin dose ranged from 125 to 2,500 mg. No systemic (neutropenia or myocardial dysfunction) or regional toxicity (extravasation, sepsis, stricture) was noted. Five of 10 patients tolerated the planned three treatment cycles. Poor performance status (PS, Eastern Cooperative Oncology Group: ECOG 3) strongly correlated with treatment intolerance and early death from disease. After three cycles of therapy, 2 of 5 evaluable patients had stable disease, I had radiographic partial response (PR) with a biopsy demonstrating extensive tumor necrosis, I had no identifiable tumor at the time of restaging transurethral resection of bladder tumor (TURBT), and a final patient with upper and lower tract carcinoma in situ (CIS) was cytologically staged NED. (no evidence of disease). These findings demonstrate the feasibility and low toxicity of this approach.

Administration, Intravesical↗
PubMed1997

Accuracy of color Doppler sonography in assessing venous thrombus extension in renal cell carcinoma.

OBJECTIVE: Our objective was to evaluate the accuracy of color Doppler sonography for assessing tumor thrombus extension into the renal veins, the inferior vena cava, and the right side of the heart in patients with renal cell carcinoma. MATERIALS AND METHODS: Over the past 4.5 years, 44 patients with 46 renal cell carcinomas were examined with color Doppler sonography for the presence and extent of tumor thrombus in the renal veins, the inferior vena cava, and the right side of the heart. Examinations were performed after an equivocal CT scan in 34 patients and as a primary imaging technique in 10. Color Doppler sonographic findings were correlated with surgical-pathologic findings or findings from autopsies performed within 3 months of the Doppler study. Seven patients were excluded: two because of poor technical quality caused by body habitus and five because pathologic correlation was performed more than 3 months after the color Doppler sonographic examination. The remaining 39 renal vein and 37 caval Doppler examinations constituted the study material. Criteria used for the diagnosis of tumor thrombus included distention of the renal vein or the inferior vena cava by echogenic material and partial or complete absence of flow detected with color Doppler sonographic examination. RESULTS: Sixteen of 39 renal veins evaluated had pathology-proven tumor thrombus. Color Doppler sonography was 87% accurate with a sensitivity of 75%, a specificity of 96%, a positive predictive value of 92%, and a negative predictive value of 85%. In two false-positive cases, involvement was limited to intrarenal veins, causing no change in the surgical approach. Five of 37 inferior venae cavae evaluated had proven involvement by tumor thrombus. Color Doppler sonography was 100% accurate in assessing the presence and extent of inferior vena caval involvement by tumor thrombus. Extension into the right atrium and ventricle that was shown by this technique was proven by surgery in one case. The overall accuracy for detecting venous involvement for both the renal veins and the inferior vena cava was 93%, the sensitivity was 81%, and the specificity was 98%. CONCLUSION: In patients with renal cell carcinoma, color Doppler sonography appears to be fairly accurate in assessing tumor extension into the renal veins, the inferior vena cava, and the right side of the heart. Although CT is the primary imaging technique for staging renal cell carcinoma, color Doppler sonography may be used as a complementary technique for assessing venous extension in patients with an equivocal CT examination.

Carcinoma, Renal Cell↗
PubMed1997

A phase II trial of deferoxamine in patients with hormone-refractory metastatic prostate cancer.

The management of hormone-refractory metastatic prostate cancer remains a therapeutic dilemma. We report the results of a phase II trial with deferoxamine administrated at a dose of 50 mg/kg (maximum dose 5 g) administered intravenously over 8 hr daily, repeated for 5 days at 4-week intervals for 2 courses. Fourteen patients with advanced hormone-refractory prostate cancer were treated and 28 courses were delivered. Essentially no toxicity was observed. Using combined clinical and prostate-specific antigen (PSA) criteria. 13 of 14 patients had disease progression. However, 9 of 14 patients had stable measurable or evaluable disease and progressed solely based on PSA criteria. Deferoxamine in this dose and schedule has no activity in hormone-refractory prostate cancer. Further investigation of the effect of deferoxamine on PSA production/expression is warranted.

Adenocarcinoma↗