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T M Wheeler

Publications and source records attributed to T M Wheeler.

At least 73 records · Page 4Linked to original sources
PubMed1997

In situ end-labeling of human testicular tissue demonstrates increased apoptosis in conditions of abnormal spermatogenesis.

OBJECTIVE: To determine, using an in situ end-labeling technique, whether the frequency of apoptosis is increased in testis biopsy specimens that demonstrate abnormal spermatogenesis. DESIGN: Immunohistochemical analysis was performed on archived paraffin-embedded testis biopsy specimens. Apoptotic indices, defined as the number of apoptotic bodies per the total number of cells or the number of Sertoli cells, were calculated after counting all the intratubular spermatogenic cells and Sertoli cells in 20 tubules. SETTING: Major academic male factor infertility clinic. PATIENT(S): Forty-eight testis biopsy specimens were obtained for routine clinical purposes from 38 men with azoospermia or severe oligozoospermia. INTERVENTION(S): In situ end-labeling was performed on archived paraffin-embedded testis biopsy specimens using terminal deoxynucleotidyl transferase. MAIN OUTCOME MEASURE(S): Apoptotic indices. RESULT(S): Significantly increased apoptotic indices were observed in patients with spermatocyte arrest, spermatid arrest, and hypospermatogenesis compared with patients with normal spermatogenesis and the Sertoli cell-only pattern. CONCLUSION(S): In situ end-labeling of testis biopsy specimens from infertile men demonstrates increased apoptosis in maturation arrest and hypospermatogenesis states compared with normal spermatogenesis and the Sertoli cell-only pattern. This unique observation implicates a prominent role for this form of programmed cell death in the pathophysiology of maturation arrest and hypospermatogenesis states.

Adult↗
PubMed1997

Apoptotic frequency is increased in spermatogenic maturation arrest and hypospermatogenic states.

PURPOSE: Increased testicular apoptosis has been observed in maturation arrest and hyposper-matogenesis states in rodent models, but this process has not yet been characterized in humans. We hypothesized that increased cell death present with accelerated apoptosis is significant in pathophysiology of many male infertility states associated with abnormal spermatogenesis. We examined frequency of apoptotic bodies in human testis biopsy specimens from infertile men using morphometric analysis of hematoxylin and eosin stained paraffin sections. MATERIALS AND METHODS: Testis biopsy specimens were obtained for routine clinical purposes from azoospermic and severely oligozoospermic men and were stained with hematoxylin and eosin. Apoptotic bodies were identified using established morphometric criteria. Apoptotic indexes, defined as apoptotic bodies per total number of cells and per Sertoli cells, were calculated after counting all intratubular spermatogenic cells and Sertoli cells in 20 tubules. RESULTS: A total of 51 biopsies was performed in 50 men. Significantly increased apoptotic body per total cell and apoptotic body per Sertoli cell ratios were observed in maturation arrest and hypospermatogenesis states in comparison to Sertoli cell only and normal spermatogenesis (p < 0.05, Mann-Whitney test). CONCLUSIONS: Increased apoptosis in maturation arrest and hypospermatogenesis states compared to normal but obstructed spermatogenesis and Sertoli cell only were observed, indicating a prominent role for this form of programmed cell death in human male infertility.

Apoptosis↗
PubMed1997

Immunohistochemical and ultrastructural study of rhabdosphincter component of the prostatic capsule.

PURPOSE: There has been no complete agreement on functional anatomy of muscular components of the urethral sphincteric mechanism, particularly in the male patient. The prostatic capsule was studied to define its histological structure and to determine whether its rhabdosphincter component (prostatocapsular rhabdosphincter) consists only of slow twitch or slow and fast twitch striated myofibers. MATERIALS AND METHODS: We studied 11 whole prostates, including 1 obtained at autopsy and 10 by radical prostatectomy. Samples of prostatic capsule from 4 operative specimens were studied by electron microscopy. Whole mount paraffin sections from transverse slices of the remaining 7 prostates were double labeled with avidin biotin conjugate immunostaining using the primary monoclonal antibodies anti-alpha smooth muscle actin plus anti-alpha sarcomeric actin (all striated myofibers) or antiskeletal myosin fast (fast myofibers only). Tissue components of the prostatic capsule, including smooth muscle and slow versus fast twitch striated myofibers, were quantified by computerized image analysis. RESULTS: The prostatic capsule consisted of collagen, smooth muscle and striated myofibers. It varied in thickness and proportion of the 3 components among specimens, and in each in relation to transverse circumferential aspect and craniocaudal (horizontal) level of the prostate. Collagen and smooth muscle were equally important components. Striated muscle elements within the capsule consisted of fast twitch and dominant slow twitch myofibers, and were much more abundant in the caudal (distal, lower) than the cranial (proximal, upper) half of the capsule, where they were deficient ventrally (anteriorly) and dorsally (posteriorly). The prostatocapsular rhabdosphincter thus had a butterfly-like appearance, with a thick posteriorly open ring at the apex and 2 thinner, divergent leaflets tapering toward the base at the bladder neck. The fast myofiber population decreased progressively from apex to base of prostate. CONCLUSIONS: Proof is provided for mixed slow and fast twitch myofiber structure of the prostatocapsular component of human male rhabdosphincter. Sustained (tonic) contraction of slow myofibers probably reinforces the role of urethral smooth muscle in maintaining continence during bladder filling. Swift contraction of fast myofibers that abound caudally in the capsule probably supplements urethral closure by the bulkier membranous urethral part of the rhabdosphincter in preventing leakage of urine under stress when voiding is imminent or willfully withheld.

Aged↗
PubMed1997

Adenovirus-mediated suicide gene therapy for experimental bladder cancer.

OBJECTIVES: To determine the feasibility, safety, and efficacy of suicide gene therapy using adenoviral-mediated herpes simplex virus thymidine kinase gene (HSV-tk) and the prodrug ganciclovir (GCV) in a murine model of human transitional cell carcinoma. METHODS: We used a replication-defective adenoviral construct containing the beta-galactosidase gene (ADV/Rous sarcoma virus [RSV]-beta-gal) as a control or ADV/RSV-tk as the therapeutic vector under the transcriptional control of the RSV long-terminal repeat promoter. Transduction efficiency was assessed in vitro by infection of MBT-2 cells with ADV/RSV-beta-gal at various multiplicities of infection (MOI) utilizing 5-bromo-4-chlor-3-indolyl-beta-D-galactoside (X-gal) staining. Sensitivity of MBT-2 cells to the therapeutic vector was determined after infection with ADV/RSV-tk with or without GCV. Subcutaneous tumors were established in syngeneic C3H/He female mice with 5 x 10(5) MBT-2 cells. Optimal dosing of ADV/RSV-tk was determined by direct percutaneous tumor injection with increasing viral doses and treatment with GCV. Treatment efficacy, long-term survival, and toxicity were determined in separate, similar, controlled experiments. RESULTS: In vitro studies indicated greater than 95% transduction 96 hours after inoculation at an MOI of 3000 and a greater than 95% cell death rate with RSV-tk + GCV at an MOI of 61 or greater. In vivo experiments demonstrated an optimal viral dose of 3 x 10(8) plaque-forming units (pfu) and a greater than fourfold reduction in tumor growth for the animals treated with ADV/RSV-tk compared with control animals (P = 0.0013). Toxicity was limited to histologic evidence of hepatitis with ADV/RSV-tk doses greater than 3 x 10(8) pfu + GCV. Long-term survival of treatment animals was significantly increased over that of control animals (59%, P = 0.0001). CONCLUSIONS: ADV/RSV-tk with GCV treatment results in efficient gene transfer in vitro and provides effective therapy in experimental murine bladder cancer by significantly inhibiting tumor growth and improving host survival.

Adenoviridae↗
PubMed1997

Hazard rates for progression after radical prostatectomy for clinically localized prostate cancer.

OBJECTIVES: We calculated the annual hazard rate (HR) for prostate cancer recurrence after radical prostatectomy (RP) to elucidate the pattern of treatment failure over time and to assess the efficacy of definitive therapy. METHODS: We calculated the progression-free probabilities (PFP) and HRs after RP for a cohort of 611 consecutive men with clinically localized (cT1-2, NX, M0) prostate cancer and no other treatment before documented progression. RESULTS: PFP for the entire study population was 78% at 5 and 76% at 10 years. The highest HR (0.09) was observed in the year immediately after surgery and dropped to 0 by year 7 (no patient recurred after year 6). Average annual HRs calculated for 3-year intervals resulted in steadily declining HRs over time for the entire study population and for all subsets, except those with a cancer pathologically confined to the prostate. Overall, the more ominous the prognostic factor, the higher the initial HR. For poorly differentiated cancers (biopsy Gleason sum 8 to 10), the HR was high in years 1 and 2 and dropped rapidly to 0 thereafter. CONCLUSIONS: Prostate-specific antigen (PSA) progression after RP usually occurred early (77% within the first 2 years) and was largely due to understaging. Late recurrences were rare in patients who were regularly evaluated with PSA. However, because the confidence intervals in our study were broad, larger patient populations with longer follow-up are needed for a definitive establishment of the time, course, and pattern of recurrence after surgery.

Adenocarcinoma↗
PubMed1997

Prognostic significance of angiogenesis in clinically localized prostate cancer (staining for Factor VIII-related antigen and CD34 Antigen.

Tumour angiogenesis is widely considered to be an important phenomenon in the process of tumour growth and metastasis. We investigated the prognostic significance of the microvascular count (MVC) in prostate cancer of each Gleason grade and compared the results to other established pathologic parameters and progression probability. We also compared the staining of Factor VIII-related antigen (FVIII-RA) with CD34 antigen (CD34 Ag) staining for determination of the MVC. We examined 101 radical prostatectomy specimens from patients who underwent curative therapy for clinically localized adenocarcinoma of the prostate as the first form of therapy. To identify microvessels, immunohistochemical staining of endothelial cells was performed using antibodies to FVIII-RA and CD34 Ag in formalin-fixed, paraffin-embedded tissue. Microvessels were counted in fivex200 fields (0.785 mm(2) on each Gleason grade in the 'hot' areas. We used the highest number of five fields in the worst Gleason grade on each staining for statistical analysis. MVC using FVIII-RA and CD34 Ag staining correlated with pathologic stage, Gleason score and preoperative serum prostate-specific antigen level. In addition, MVC using CD34 Ag staining also correlated with DNA ploidy and total tumour volume. The Gleason score was found to be the best prognostic indicator using Cox proportional hazards regression analysis. In this study, MVC in prostate cancer was predictive of pathologic stage and Gleason grade, but MVC by either FVIII-RA and CD34 Ag staining was not an independent prognostic predictor. The best prognostic indicator in this study was Gleason score.

Journal Article↗
PubMed1997

The striated urethral sphincter: muscle fibre types and distribution in the prostatic capsule.

OBJECTIVE: To clarify the muscle fibre types in the striated urethral sphincter and the pattern of distribution of this muscle in the prostatic capsule. MATERIALS AND METHODS: Twenty-three prostate glands obtained at radical prostatectomy were studied using a whole-organ technique. Each gland was sectioned from prostatic apex to base, including the bladder neck and seminal vesicles. The slides were then traced on paper after staining with haematoxylin and eosin and the distribution of striated muscle mapped. Two prostates were studied after sectioning with a cryostat and staining with adenosine phosphatase at pH 4.2, 4.6 and 4.93 to distinguish between the sub-classification of Type 2 fibres. Other sections were stained for nicotinamide adenine dinucleotide phosphate with nitroblue tetrazolium, to distinguish fast from slow twitch fibres. RESULTS: Striated muscle was present within the anterolateral aspect of the prostatic capsule, extending from the prostatic apex to the bladder neck. Three different fibre types were present; fast-twitch fatigue-sensitive, fast-twitch fatigue-resistant and slow-twitch. CONCLUSION: There are three distinct fibre types in the prostatic capsular striated muscle, representing displaced muscle fibres from the striated urethral sphincter. The composition of three types makes it eminently suitable to function as a sphincter muscle.

Histocytochemistry↗
PubMed1997

Has there been a recent shift in the pathological features and prognosis of patients treated with radical prostatectomy?

PURPOSE: We determined if there has been a significant change in pathological stage or prognosis of patients with clinically localized prostate cancer treated with radical prostatectomy between 1983 and 1995. During this period the methods of detection of prostate cancer changed to include, in recent years, a large proportion of nonpalpable cancers detected by prostate specific antigen (PSA). MATERIALS AND METHODS: The method of diagnosis, pathological features and prognosis (PSA detected progression-free probability) of 754 consecutive patients treated by 1 surgeon for clinical stages T1 to 3NXMO prostate cancer from 1983 to 1995 were analyzed by year of diagnosis. RESULTS: There was a marked increase in the annual number of radical prostatectomies performed with time. The proportion of cancers initially detected by transurethral resection decreased markedly after 1989. Beginning in 1990 nonpalpable cancers detected by PSA increased substantially to 52% by 1995. However, there was no significant change in preoperative serum PSA, tumor volume or pathological stage during the study period. The proportion of patients with well differentiated cancer decreased somewhat, while those with moderate to poorly differentiated (Gleason sum 7) cancers increased significantly after 1991. There was no increase with time in the proportion of patients with a small (less than 0.5 cm.3), well or moderately differentiated (Gleason grades 1 to 3) cancer confined to the prostate (an indolent or clinically unimportant cancer) but fewer patients in recent years had an advanced cancer (established extraprostatic extension with a positive surgical margin, seminal vesicle invasion or lymph node metastases). The actuarial probability of progression after surgery was similar for patients treated from 1983 to 1987, 1988 to 1991 and 1992 to 1995. CONCLUSIONS: Despite marked changes in the number of patients treated each year and the method by which cancers were first detected, we found no change in pathological stage or prognosis (progression rate) for patients treated with radical prostatectomy between 1983 and 1995. Despite concerns that the increased detection of prostate cancer could lead to many more patients being treated unnecessarily for small, indolent cancers, we found no increase in the proportion of such cancers with time.

Actuarial Analysis↗
PubMed1997

Primary human prostate cancer cells harboring p53 mutations are clonally expanded in metastases.

Recent studies suggest a role for p53 in prostate cancer progression. Although p53 mutations in primary prostate cancer tissues are relatively infrequent, they occur at significant levels in metastatic disease. Here we describe a novel approach to the molecular analysis of p53 in paired specimens of primary and metastatic prostate cancer that results in quantitative estimates of the extent of clonal expansion. In 20 pairs with 1 or both specimens p53 immunopositive and in 6 pairs with both specimens immunonegative, the frequency of mutations was estimated by microdissection of the cancer from fixed and sectioned tissues, isolation of the DNA followed by PCR amplification of p53 genomic fragments, and cloning of the PCR products into plasmid vectors. At least 90 clones/tissue specimen were screened for mutations by single-strand conformational polymorphism analysis. DNA from abnormally migrating single-strand conformational polymorphism samples was sequenced to confirm mutations. Missense mutations in exon 5, 7, or 8 were detected in 9 of 20 immunopositive pairs and in 1 of 6 immunonegative pairs. A marked heterogeneity of mutations in primary prostate cancer was apparent. The frequency of p53 mutations was greater in the metastases than in the primary tumors. In three immunopositive pairs, the same p53 mutation was demonstrated at a low frequency in the primary tumor but was demonstrated at a greater frequency in the metastasis, indicating relatively limited clonal expansion of cells harboring specific p53 mutations in the primary tumor, yet significant clonal growth at metastatic sites as determined by this novel method.

Amino Acid Substitution↗
PubMed1996

Perineural invasion of prostate carcinoma cells is associated with reduced apoptotic index.

BACKGROUND: Prostate carcinoma is often associated with perineural (PN) invasion. The common occurrence of this phenomenon has led to speculation regarding the mechanisms of this association, yet to date there have been no studies that clearly define biologic differences between PN and nonperineural (NPN) carcinoma cells. To explore the mechanisms underlying PN invasion by prostate carcinoma cells, the authors investigated the influence of neural components on the growth potential of prostate carcinoma cells. METHODS: Proliferative and apoptotic activities of PN and NPN carcinoma cells were analyzed on whole-mount sections of human prostates using immunohistochemical techniques in conjunction with a polyclonal Ki-67 antiserum, and the terminal deoxynucleotidyl transferase (TdT) mediated dUTP biotin nick end labeling (TUNEL) technique, respectively. RESULTS: The proliferative index (Ki-67 positive cells per 100 carcinoma cells) of PN carcinoma cells (median, 4.10) was higher than that of their intraprostatic, NPN counterparts (median, 3.25), although the difference was not statistically significant (median difference, 0.38; 95% confidence interval [CI] = -0.99 to 1.32; P = 0.52). In contrast, the apoptotic index (AI = apoptotic bodies per 1000 carcinoma cells) in the NPN carcinoma cells was significantly lower (median, 4.10), than the PN carcinoma cells (median, 7.23) with a median difference of -3.45 (95% CI = -5 to -1.39; P = 0.02). The authors also found that AI was lower in the carcinoma cells surrounding nerves with a large diameter (P = 0.0005). CONCLUSIONS: These results suggest that PN invasion by prostate carcinoma cells may not be only a volume effect of growing carcinomas; the neural components may favor the growth of carcinoma cells by inhibiting apoptosis, presumably through a paracrine mechanism, and thereby facilitate the spread of carcinoma cells along nerves. The data also suggest that heterogeneity in growth potential of prostate carcinoma cells may be determined by their local microenvironments, such as an association with neural components.

Adenocarcinoma↗
PubMed1996

Optimized microvessel density analysis improves prediction of cancer stage from prostate needle biopsies.

OBJECTIVES: Clinical staging of prostate cancer is inaccurate, often with significant upstaging on final pathologic review. We previously demonstrated the ability to predict extraprostatic extension of cancer by use of the Gleason score and serum prostate-specific antigen (PSA) measurements. Herein we present an interim analysis of data from an ongoing multi-institutional study to determine the predictive power of an enhancement of microvessel density analysis in combination with Gleason score and serum PSA to predict extraprostatic extension. METHODS: We evaluated a total of 186 randomly selected biopsy samples and matched totally embedded radical prostatectomy samples with preoperative PSA concentrations and patient demographics. Gleason score and optimized microvessel density (OMVD) were determined from the needle biopsy samples; pathologic stage was verified by independent review of the radical prostatectomy samples. An automated digital image analysis system measured microvessel morphology and calculated the OMVD in the biopsy samples (Biostage; Bard Diagnostic Sciences, Seattle, Wash). RESULTS: Prediction of extraprostatic extension was increased significantly when OMVD analysis was added to Gleason score and serum PSA concentration (P = 0.003). CONCLUSIONS: Optimized microvessel density analysis significantly increases the ability to predict extraprostatic extension of cancer preoperatively when combined with Gleason score and serum PSA concentration. This method appears to be a useful tool that can assist with treatment decisions in selected patients.

Aged↗
PubMed1996

Impalpable prostate cancer: clinicopathological features.

OBJECTIVE: To determine the clinicopathological features of impalpable prostate cancer. PATIENTS, MATERIALS AND METHODS: The numbers of T1a and T1b cancers detected in transurethral resections of the prostate (TURP) performed before and after the advent of the test for serum prostate-specific antigen (PSA) were compared and the incidence of T1 disease in specimens from 400 consecutive radical prostatectomies examined. RESULTS: The incidence of T1b disease detected at TURP decreased significantly between the periods examined, but that of T1a was unaffected. Similarly, in radical prostatectomy specimens, T1b cancers were largely replaced by T1c and impalpable T2 cancers detected by ultrasonography. CONCLUSIONS: Cancers detected incidentally at TURP tend to be small T1a tumours, possibly suitable for conservative management. T1b cancers are likely to be detected by PSA level and treated radically. T1c and impalpable T2 cancers are morphologically unlike T1b disease and justifiably belong in separate stages in the current UICC staging system.

Aged↗
PubMed1996

Influence of irradiation and androgen ablation on prostatic intraepithelial neoplasia.

OBJECTIVES: Although irradiation and endocrine therapy have been used in the treatment of prostatic carcinoma for several decades and the effects of such therapy on carcinoma and the normal prostate have been well described and although there is ample evidence linking prostatic intraepithelial neoplasia (PIN) to the origin of prostatic adenocarcinoma, there is little published information on the effect of such therapies on PIN. METHODS AND RESULTS: The extant literature on this subject is reviewed and analyzed. The literature on total androgen blockade is not extensive but adequate to draw conclusions. The literature on irradiation therapy is minimal and inadequate to draw definite conclusions. CONCLUSIONS: The available evidence indicates that the prevalence and extent of PIN in prostates that have been treated with endocrine therapy is reduced from what might otherwise be expected. Irradiation therapy may have little effect on the prevalence of PIN but might influence the extent of PIN.

Androgen Antagonists↗
PubMed1996

Distinguishing clinically important from unimportant prostate cancers before treatment: value of systematic biopsies.

PURPOSE: We assessed the ability of diagnostic tests to distinguish clinically unimportant cancers. MATERIALS AND METHODS: We correlated T stage (based on digital examination and ultrasound), prostate specific antigen (PSA), PSA density and pathological features of cancer in systematic biopsy specimens with features of cancer in 170 radical prostatectomy specimens. Clinically unimportant cancers were defined as small (0.5 cm.3 or less), well or moderately differentiated and confined to the prostate. RESULTS: Of the patients 10% had an unimportant cancer. On logistic regression analysis the 2 significant predictors were maximum length of cancer in any core and PSA density. Of 12 patients with maximum cancer length 2 mm. or less and PSA density less than 0.1., 75% had an unimportant cancer compared to 5% of the remaining 158 (p < 0.0005). CONCLUSIONS: Quantitative analysis of systematic biopsy specimens combined with PSA density provides valuable staging information and helps to identify cancers of low biological potential.

Aged↗
PubMed1996

Clustered p53 immunostaining: a novel pattern associated with prostate cancer progression.

Abnormal p53 protein accumulation is typically defined as present when greater than 5 or 10% of cancer cells stain positively. We present a novel approach whereby immunopositivity is defined when 15 or more cells within a 300 x 400-micrometer(2) field exhibit p53 protein accumulation; a feature that we have called "clustered" staining. We assessed p53 immunostaining of moderately differentiated, clinically localized prostate cancers derived from two patient groups: those without cancer recurrence 5 years after radical prostatectomy, and those in whom cancer had recurred following radical prostatectomy. Clustered p53 immunopositivity was present in 10 (63%) of 16 patients in the recurrent group and in only 7 (21%) of 33 in the nonrecurrent group. Clustered p53 staining was clearly associated with cancer recurrence (P < 0.01). This refinement of a commonly used assay may help define the biological aggressiveness of a cancer.

Humans↗
PubMed1996

Reduced levels of transforming growth factor beta receptor type II in human prostate cancer: an immunohistochemical study.

In previous studies we demonstrated that the growth of human prostatic adenocarcinoma is associated with aberrant accumulation of transforming growth factor (TGF) beta1, a growth factor that has been shown to be a potent inhibitor of epithelial cell proliferation. We investigated the expression of TGF-beta receptor II (TGFbetaR-II) in benign prostate tissue and in prostate cancer using standard immunohistochemical techniques. Quantitation of immunopositivity for TGFbetaR-II was assessed on a visual analogue scale ranging from 0 (absence of staining) to 4+ (intensely positive staining). All of the benign glandular epithelia stained intensely, either 3+ or 4+, representative of the ubiquitous nature of TGFbetaR-II in normal tissue. Overall, staining was reduced in prostate cancer sections, and there was progressively diminished staining as the histological grade of the cancer increased (P < 0.01, Kruskal-Wallis test). This immunohistochemical study indicates that a decline in the levels of TGFbetaR-II is correlated with advancing histological aggressiveness of the cancer and suggests that aberrant TGFbetaR-II function may play a role in human prostate carcinogenesis.

Aged↗
PubMed1995

Distant metastasis after radical prostatectomy in patients without an elevated serum prostate specific antigen level.

BACKGROUND: Serum prostate specific antigen (PSA) is a sensitive indicator of prostate cancer recurrence after radical prostatectomy. Prostate cancer rarely recurs after radical surgery without PSA elevation. Of the few patients noted in the literature who had a recurrence of cancer without PSA elevation, all had local recurrence alone, except for one, who had bone metastases. METHODS: In the authors' series of 628 patients, PSA was the first indicator of recurrence in all but 2 (2.6%) of 77 patients with clinical T1-T3NxM0 classification prostate cancer. RESULTS: Two of our patients, despite having undetectable PSA levels, had distant recurrence, including one with multiple visceral (lung and brain) metastases. CONCLUSIONS: These two cases demonstrate that although uncommon, prostate cancer can recur and metastasize after radical prostatectomy without an increase in the serum PSA level.

Aged↗