First Experimental Characterization of Microwave Emission from Cosmic Ray Air Showers.

We report the first direct measurement of the overall characteristics of microwave radio emission from extensive air showers. Using a trigger provided by the KASCADE-Grande air shower array, the signals of the microwave antennas of the Cosmic-Ray Observation via Microwave Emission experiment have been read out and searched for signatures of radio emission by high-energy air showers in the GHz frequency range. Microwave signals have been detected for more than 30 showers with energies above 3×10^{16} eV. The observations presented in this Letter are consistent with a mainly forward-directed and polarized emission process in the GHz frequency range. The measurements show that microwave radiation offers a new means of studying air showers at E≥10^{17} eV.

Treatment of local-regional prostate cancer detected by PSA screening: benefits and harms according to prognostic factors.

BACKGROUND: Men with screen-detected prostate cancer can choose to undergo immediate curative treatment or enter into an expectant management programme. We quantified how the benefits and harms of immediate treatment vary according to the prognostic factors of clinical T-stage, Gleason score, and patient age. METHODS: A microsimulation model based on European Randomized Study of Screening for Prostate Cancer data was used to predict the benefits and harms of immediate treatment versus delayed treatment of local-regional prostate cancer in men aged 55-74 years. Benefits included life-years gained and reduced probability of death from prostate cancer. Harms included lead time and probability of overdiagnosis. RESULTS: The ratio of mean lead time to mean life-years gained ranged from 1.8 to 31.2, and the additional number of treatments required per prostate cancer death prevented ranged from 0.3 to 11.6 across the different prognostic groups. Both harm-benefit ratios were lowest, most favourable, for men aged 55-59 years and diagnosed with moderate-risk prostate cancer. Ratios were high for men aged 70-74 years regardless of clinical T-stage and Gleason score. CONCLUSION: Men aged 55-59 years with moderate-risk prostate cancer are predicted to derive greatest benefit from immediate curative treatment. Immediate treatment is least favourable for men aged 70-74 years with either low-risk or high-risk prostate cancer.

Androgen deprivation therapy: past, present and future.

Since Huggins and Hodges demonstrated the responsiveness of prostate cancer to androgen deprivation therapy (ADT), androgen-suppressing strategies have formed the cornerstone of management of advanced prostate cancer. Approaches to ADT have included orchidectomy, oestrogens, luteinizing hormone-releasing hormone (LHRH) agonists, anti-androgens and more recently the gonadotrophin-releasing hormone antagonists. The most extensively studied antagonist, degarelix, avoids the testosterone surge and clinical flare associated with LHRH agonists, offering more rapid PSA and testosterone suppression, improved testosterone control and improved PSA progression-free survival compared with agonists. The clinical profile of degarelix appears to make it a particularly suitable therapeutic option for certain subgroups of patients, including those with metastatic disease, high baseline PSA (>20 ng/mL) and highly symptomatic disease. As well as forming the mainstay of treatment for advanced prostate cancer, ADT is increasingly used in earlier disease stages. While data from clinical trials support the use of ADT neoadjuvant/adjuvant to radiotherapy for locally advanced or high-risk localized prostate cancer, it remains to be established whether specific ADT classes/agents provide particular benefits in this clinical setting.

Importance of prostate volume in the European Randomised Study of Screening for Prostate Cancer (ERSPC) risk calculators: results from the prostate biopsy collaborative group.

OBJECTIVES: To compare the predictive performance and potential clinical usefulness of risk calculators of the European Randomized Study of Screening for Prostate Cancer (ERSPC RC) with and without information on prostate volume. METHODS: We studied 6 cohorts (5 European and 1 US) with a total of 15,300 men, all biopsied and with pre-biopsy TRUS measurements of prostate volume. Volume was categorized into 3 categories (25, 40, and 60 cc), to reflect use of digital rectal examination (DRE) for volume assessment. Risks of prostate cancer were calculated according to a ERSPC DRE-based RC (including PSA, DRE, prior biopsy, and prostate volume) and a PSA + DRE model (including PSA, DRE, and prior biopsy). Missing data on prostate volume were completed by single imputation. Risk predictions were evaluated with respect to calibration (graphically), discrimination (AUC curve), and clinical usefulness (net benefit, graphically assessed in decision curves). RESULTS: The AUCs of the ERSPC DRE-based RC ranged from 0.61 to 0.77 and were substantially larger than the AUCs of a model based on only PSA + DRE (ranging from 0.56 to 0.72) in each of the 6 cohorts. The ERSPC DRE-based RC provided net benefit over performing a prostate biopsy on the basis of PSA and DRE outcome in five of the six cohorts. CONCLUSIONS: Identifying men at increased risk for having a biopsy detectable prostate cancer should consider multiple factors, including an estimate of prostate volume.

A four-kallikrein panel for the prediction of repeat prostate biopsy: data from the European Randomized Study of Prostate Cancer screening in Rotterdam, Netherlands.

BACKGROUND: Most men with elevated levels of prostate-specific antigen (PSA) do not have prostate cancer, leading to a large number of unnecessary biopsies. A statistical model based on a panel of four kallikreins has been shown to predict the outcome of a first prostate biopsy. In this study, we apply the model to an independent data set of men with previous negative biopsy but persistently elevated PSA. METHODS: The study cohort consisted of 925 men with a previous negative prostate biopsy and elevated PSA (>or=3 ng ml(-1)), with 110 prostate cancers detected (12%). A previously published statistical model was applied, with recalibration to reflect the lower positive biopsy rates on rebiopsy. RESULTS: The full-kallikrein panel had higher discriminative accuracy than PSA and DRE alone, with area under the curve (AUC) improving from 0.58 (95% confidence interval (CI): 0.52, 0.64) to 0.68 (95% CI: 0.62, 0.74), P<0.001, and high-grade cancer (Gleason >or=7) at biopsy with AUC improving from 0.76 (95% CI: 0.64, 0.89) to 0.87 (95% CI: 0.81, 0.94), P=0.003). Application of the panel to 1000 men with persistently elevated PSA after initial negative biopsy, at a 15% risk threshold would reduce the number of biopsies by 712; would miss (or delay) the diagnosis of 53 cancers, of which only 3 would be Gleason 7 and the rest Gleason 6 or less. CONCLUSIONS: Our data constitute an external validation of a previously published model. The four-kallikrein panel predicts the result of repeat prostate biopsy in men with elevated PSA while dramatically decreasing unnecessary biopsies.

Combinatorial chemistry in insects: a library of defensive macrocyclic polyamines.

The pupal defensive secretion of the coccinellid beetle Epilachna borealis is composed principally of a combinatorial library of macrocyclic polyamines. These compounds constitute a previously unrecognized family of natural products, characterized by extremely large-ring lactonic structures derived from a small set of (2-hydroxyethylamino)alkanoic acids. The combinatorial assembly of these simple building blocks generates a high degree of structural diversity, which is further increased by slow, spontaneous intramolecular rearrangement of the macrocycles.

Low-field magnetic resonance imaging offers potential for measuring tibial component migration.

BACKGROUND: Roentgen stereophotogrammetric analysis (RSA) is used to measure early prosthetic migration and to predict future implant failure. RSA has several disadvantages, such as the need for perioperatively inserted tantalum markers. Therefore, this study evaluates low-field MRI as an alternative to RSA. The use of traditional MRI with prostheses induces disturbing metal artifacts which are reduced by low-field MRI. The purpose of this study is to assess the feasibility to use low-field (0.25 Tesla) MRI for measuring the precision of zero motion. This was assessed by calculating the virtual prosthetic motion of a zero-motion prosthetic reconstruction in multiple scanning sessions. Furthermore, the effects of different registration methods on these virtual motions were tested. RESULTS: The precision of zero motion for low-field MRI was between 0.584 mm and 1.974 mm for translation and 0.884° and 3.774° for rotation. The manual registration method seemed most accurate, with µ ≤ 0.13 mm (σ ≤ 0.931 mm) for translation and µ ≤ 0.15° (σ ≤ 1.63°) for rotation. CONCLUSION: Low-field MRI is not yet as precise as today's golden standard (marker based RSA) as reported in the literature. However, low-field MRI is feasible of measuring the relative position of bone and implant with comparable precision as obtained with marker-free RSA techniques. Of the three registration methods tested, manual registration was most accurate. Before starting clinical validation further research is necessary and should focus on improving scan sequences and registration algorithms.

Very late local recurrence after surgery for prostate cancer unaccompanied by detectable PSA levels.

The possibility and possible aetiology of local prostate cancer (PC) recurrence despite undetectable prostate-specific antigen (PSA) levels are highlighted. A case of a local recurrence 8.5 years after radical prostatectomy for Gleason 3+4 PC is presented. It demonstrates that PC can recur, even after a prolonged period of time (8.5 years), despite undetectable levels (i.e. <0.02 ng/ml) of PSA. In conclusion, the decision to omit digital rectal examination from the follow-up regimens of men with undetectable PSA levels could be justified. In such exceptional cases, however, PC recurrence would be either missed or would only be diagnosed after a considerable delay.

Evaluation of the digital rectal examination as a screening test for prostate cancer. Rotterdam section of the European Randomized Study of Screening for Prostate Cancer.

BACKGROUND: The utility of digital rectal examination (DRE) as a screening test for early detection of prostate cancer has not been established. Therefore, we evaluated the usefulness of DRE as a stand-alone screening test and in conjunction with measured serum prostate-specific antigen (PSA) levels of 0-3.9 ng/mL and transrectal ultrasonography (TRUS). METHODS: Our study population consisted of 10,523 men aged 54-76 years who were randomly assigned to the screening arm of the Rotterdam, The Netherlands, section of the European Randomized Study of Screening for Prostate Cancer. The underlying prevalence of detectable prostate cancer was estimated by logistic regression analysis and used for calculating the sensitivity of DRE as a test. Pathologic characteristics of 105 radical prostatectomy specimens were used to determine the aggressiveness of the tumors diagnosed (and missed) by DRE. RESULTS: The overall detection rate for prostate cancer in this population when serum PSA measurement, DRE, and TRUS were used was 4.5%, and the detection rate with DRE alone was 2.5%. The positive predictive value of DRE ranged from 4% to 11% in men with PSA levels of 0-2.9 ng/mL and from 33% to 83% in men with PSA levels of 3.0-9.9 ng/mL or more. Most tumors detected by DRE in men with PSA levels of less than 4.0 ng/mL were small (mean volumes = 0.24-0.83 mL), and most were well differentiated (Gleason scores of 6 or less). Minimal, moderate, and advanced cancers were seen in 42%, 42%, and 16% of men, respectively, with a PSA level of 4.0 ng/mL or less. DRE alone allowed detection of 264 (55.8%) of 473 cancers; 82 (17.3%) of the 473 cancers would have remained undetected by PSA-based screening alone (i.e., no follow-up procedures for PSA values of 0-3.9 ng/mL). CONCLUSIONS: For PSA values of 0-3.9 ng/mL, the positive predictive value and sensitivity of DRE, tumor volume, and tumor grade were strongly dependent on PSA level. DRE has a poor performance in low PSA ranges.

Short-term effects of population-based screening for prostate cancer on health-related quality of life.

BACKGROUND: Population-based screening for prostate cancer is currently being evaluated in randomized clinical trials in the United States and in Europe. Side effects arising from the process of screening and from the earlier treatment of screen-detected prostate cancer may be important factors in the evaluation. To examine health-related quality of life (or health status) among men screened for prostate cancer, we conducted a longitudinal study of 626 attenders to the Rotterdam (The Netherlands) prostate cancer screening program and of 500 nonparticipants. METHODS: Attenders of the screening program and nonparticipants completed self-assessment questionnaires (SF-36 [i.e., Medical Outcomes Study 36-Item Short-Form Health Survey] and EQ-5D [i.e., EuroQol measure for health-related quality of life] health surveys) to measure generic health status, as well as an additional questionnaire for anxiety and items relating to prostate cancer screening. RESULTS: Physical discomfort during digital rectal examination and during transrectal ultrasound was reported by 181 (37%) of 491 men and by 139 (29%) of 487 men, respectively; discomfort during prostate biopsy was reported by 64 (55%) of 116 men. Mean scores for health status and anxiety indicated that the participants did not experience relevant changes in physical, psychological, and social functioning during the screening procedure. However, high levels of anxiety were observed throughout the screening process among men with a high predisposition to anxiety. Similar scores for anxiety predisposition were observed among attenders and nonparticipants. CONCLUSIONS: At the group level, we did not find evidence that prostate cancer screening induced important short-term health-status effects, despite the short-lasting side effects related to the biopsy procedure. However, subgroups may experience high levels of anxiety. The implication is that unfavorable health-status effects of prostate cancer screening occur mainly in the treatment phase.

Pathologic features of prostate cancer found at population-based screening with a four-year interval.

BACKGROUND: The currently recommended frequency for prostate-specific antigen (PSA) screening tests for prostate cancer is 1 year, but the optimal screening interval is not known. Our goal was to determine if a longer interval would compromise the detection of curable prostate cancer. METHODS: A cohort of 4491 men aged 55-75 years, all participants in the Rotterdam section of the European Randomized Study of (population-based) Screening for Prostate Cancer, were invited to participate in an initial PSA screening. Men who received that screening were invited for a second screen 4 years later. Pathology findings from needle biopsy cores were compared for men in both rounds. Statistical tests were two-sided. RESULTS: A total of 4133 men were screened in the first round (the prevalence screen), and 2385 were screened in the second round. The median amount of cancer in needle biopsy sets was 7.0 mm (95% confidence interval [CI] = 5.4 mm to 8.6 mm) in the first round and 4.1 mm (95% CI = 2.6 mm to 5.6 mm) in the second round (P =.001). Thirty-six percent of the adenocarcinomas detected in the first round but only 16% of those detected in the second round had a Gleason score of 7 or higher (mean difference = 20% [95% CI = 10% to 30%]; P<.001). Whereas 25% of the adenocarcinomas detected in the first round had adverse prognostic features, only 6% of those detected in the second round did (mean difference = 19% [95% CI = 11% to 26%]; P<.001). Baseline PSA values were predictive for the amount of tumor in biopsies in men with cancer in the first round but not for that in the second round. CONCLUSION: Most large prostate cancers with high serum PSA levels were effectively detected in a prevalence screen. In this population, a screening interval of 4 years appears to be short enough to constrain the development of large tumors, although it is inconclusive whether this will result in a survival benefit.

Androgen deprivation of the PC-310 [correction of prohormone convertase-310] human prostate cancer model system induces neuroendocrine differentiation.

Neuroendocrine (NE) cells are androgen-independent cells and secrete growth-modulating neuropeptides via a regulated secretory pathway (RSP). We studied NE differentiation after androgen withdrawal in the androgen-dependent prostate cancer xenograft PC-310. Expression patterns of chromogranin A, secretogranin III, and prohormone convertase-1 were analyzed at both protein and mRNA level to mark the kinetics of NE differentiation both in vivo and in vitro. PC-310 tumor-bearing nude mice were killed at 0, 2, 5, 7, 14, and 21 days postcastration. PC-310C cultures initiated from collagenase-treated tumor tissue could be maintained up to four passages, and androgen-deprivation experiments were performed similarly. PC-310 tumor volumes decreased by 50% in 10 days postcastration. Proliferative activity and prostate-specific antigen (PSA) serum levels decreased to zero postcastration, whereas PSA levels in PC-310C culture media first decreased and subsequently increased after 5 days. In vivo, androgen receptor (AR) expression decreased initially but returned to control level from 5 days postcastration on. CgA, secretogranin III, and secretogranin V expression increased in vivo from 5 days postcastration on. Subsequently, prohormone convertase-1 and peptidyl alpha-amidating monooxygenase as well as the vascular endothelial growth factor were expressed from 7 days postcastration on, and, finally, growth factors such as gastrin-releasing peptide and serotonin were expressed in a small part of the NE cells 21 days postcastration. The PC-310 tumors did not show colocalization of the AR on the NE cells in the tumor residues after 21 days. As in the PC-310 xenograft, NE differentiation was induced and AR expression relapsed after prolonged androgen suppression in PC-310C. For PC-310C cells, this relapse was associated with the secretion of PSA. PC-310C is the first culture of human prostatic cancer cells having the NE phenotype. The PC-310 model system is a potential androgen-dependent model for studying the role of NE cells in the progression of clinical prostate cancer. Androgen deprivation of NE-differentiated prostate cancer may induce the formation of both NE- and AR-positive dormant tumor residues, capable of actively producing NE growth factors via a RSP, possibly leading to hormone refractory disease.

Loss of heterozygosity of chromosome 8 microsatellite loci implicates a candidate tumor suppressor gene between the loci D8S87 and D8S133 in human prostate cancer.

To search for specific chromosome 8 aberrations in human prostate cancer, DNA was isolated from 44 human prostate tumor samples. Twenty six tumor samples were obtained from locally progressive tumors by transurethral resection, 12 were from radical prostatectomy specimens, and 6 were from lymph node metastases. Tumor DNAs were screened for allelic losses using 16 highly polymorphic microsatellite loci (14 covering the p arm, 2 on the q arm). In general, the detected deletions were large. In 59% of the tumor DNAs, allelic loss of 3 or more 8p loci was observed. Loss of 8p loci occurred in between 36 and 69% of the informative cases; for the two 8q markers, the percentages of loss were 11 and 25%, respectively, indicating preferential loss of (part of) 8p. In one tumor, two separate 8p deletions were found. The percentage of loss of heterozygosity was considerably higher in transurethral resection (65%) and lymph node metastases (83%) than in radical prostatectomy specimens (33%), suggesting that 8p deletion is a relatively late step in tumor progression. The maximal overlapping deleted region in all tumor DNAs is between the distal locus D8S133 and the proximal locus D8S87, indicating the localization of a candidate tumor suppressor gene within this region.

Health-related quality-of-life effects of radical prostatectomy and primary radiotherapy for screen-detected or clinically diagnosed localized prostate cancer.

PURPOSE: The current study was undertaken within the framework of a screening trial to compare the health-related quality-of-life (HRQOL) outcomes of two primary treatment modalities for localized prostate cancer: radical prostatectomy and external-beam radiotherapy. PATIENTS AND METHODS: We conducted a prospective longitudinal cohort study among 278 patients with early screen-detected (59%) or clinically diagnosed (41%) prostate cancer using both generic and disease-specific HRQOL measures (SF-36, UCLA Prostate Cancer Index [urinary and bowel modules] and items relating to sexual functioning) at three points in time: t1 (baseline), t2 (6 months later), and t3 (12 months after t1). RESULTS: Questionnaires were completed by 88% to 93% of all initially enrolled patients. Patients referred for primary radiotherapy were significantly older than prostatectomy patients (63 v 68 years, P <.01). Analyses (adjusted for age and pretreatment level of functioning) revealed poorer levels of generic HRQOL after radiotherapy. Prostatectomy patients reported significantly higher (P <.01) posttreatment incidences of urinary incontinence (39% to 49%) and erectile dysfunction (80% to 91%) than radiotherapy patients (respectively, 6% to 7% and 41% to 55%). Bowel problems (urgency) affected 30% to 35% of the radiotherapy group versus 6% to 7% of the prostatectomy group (P <.01). Patients with screen-detected and clinically diagnosed cancer reported similar posttreatment HRQOL. CONCLUSION: Prostatectomy and radiotherapy differed in the type of HRQOL impairment. Because the HRQOL effects may be valued differently at the individual level, patients should be made fully aware of the potential benefits and adverse consequences of therapies for early prostate cancer. Differences in posttreatment HRQOL were not related to the method of cancer detection.

Screening for prostate cancer.

Epidemiologically, prostate cancer is the most common cancer in the Western world after skin cancer. To date, it is still unknown whether screening for prostate cancer is justified, because results of randomised clinical trials are not yet available. The available screening tests (i.e. prostate-specific antigen (PSA) test) do not always detect cancers that otherwise would have resulted in prostate cancer mortality. Favourable results from prostate cancer screening include an increasing number of men with localised disease and an increase in the number of well-differentiated tumours. However, the risk of overdiagnosis and subsequent over-treatment (due to the diagnosis of localised disease), using aggressive therapies fuels arguments against screening. Therefore, until more evidence is available proving otherwise, prostate cancer screening can only be justified in the context of clinical trials.

The prognostic value of CD44 isoforms in prostate cancer patients treated by radical prostatectomy.

CD44 forms a group of transmembranous glycoproteins formed by alternative splicing of a single mRNA. The expression of v6 exon-containing variants correlates with metastasis and poor prognosis in a number of malignancies. The distribution and prognostic value of CD44s, CD44v5, and CD44v6 were studied immunohistochemically in the radical prostatectomy specimens of 97 patients with prostate cancer and in 12 lymph node metastases. The mean follow-up period was 84 months. The percentage of CD44-immunoreactive cells was scored semiquantitatively. CD44 mRNA expression was studied in nine prostate cancer and eight benign prostatic hyperplasia (BPH) samples by reverse transcriptase-PCR. Benign prostatic glands almost always expressed CD44s, CD44v6, and, at a lower intensity, CD44v5. CD44 scores decreased from low- to high-grade prostatic intraepithelial neoplasia. CD44s, CD44v5, and CD44v6 were expressed in 86, 23, and 69% of the adenocarcinomas, respectively. Gleason sum score (GSS) and pT stage were correlated inversely with CD44s and CD44v6 scores. CD44 was not found in the lymph node metastatic tumor cells. At the mRNA level, 89% of the tumors and all BPH samples expressed CD44s. CD44v6-v10 mRNA was present in 44 and 75% of the tumors and BPH samples, respectively. Loss of CD44s and CD44v6 predicted an adverse prognosis at univariate analysis. The independent prognosticators identified by multivariate analysis were: GSS, pT stage, and CD44s for clinical progression; GSS and CD44s for prostate-specific antigen progression; and GSS for tumor-specific survival. Loss of CD44s expression in prostate adenocarcinoma predicts a poor prognosis, independent of stage and grade.

Features of prostate cancers detected during a prevalence screening round. The Rotterdam experience.

INTRODUCTION: Prostate-specific antigen (PSA) testing of asymptomatic men may lead to the detection of "minimal" prostate cancers that are less likely to be associated with morbidity or mortality. OBJECTIVE: To examine the significance of various diagnostic outcomes from needle biopsies of the prostate in an asymptomatic population of men. METHODS: Prostatic needle biopsy findings were matched with those from radical prostatectomy specimens using data from the Rotterdam section of the European Randomized study of Screening for Prostate Cancer (ERSPC). Men, aged between 55 and 75 years, with elevated PSA levels underwent lateralized sextant needle biopsies. In corresponding radical prostatectomy specimens, the tumor categories (minimal, moderate, or advanced) were determined. RESULTS: Prostate cancer was diagnosed in 5.1% of 19,970 screened men, and 31.6 % of the men had cancers that were categorized as "minimal." Repeat biopsies performed after initial diagnoses of either isolated prostatic intra-epithelial neoplasia (PIN) or "suspicious for malignancy," detected adenocarcinoma in 12.1%and 36.5 % of the men, respectively. In a substudy of 510 men with a benign biopsy outcome 12 months previously, repeat biopsies detected adenocarcinoma in 12.4 of the men. Of men who were subsequently treated with radical prostatectomy, the cancers were classified as "minimal" in 27.8% of the men with previously benign biopsies and in 47.4% of the men with previously suspicious lesions, CONCLUSIONS: The chance of finding a "minimal" prostate cancer in an asymptomatic population is substantial and increases when a repeat biopsy is performed following a biopsy with a suspicious outcome.

[Diagnosis based on prostate needle biopsy: inadequate correlation between pathologic results and clinical course for individual prognosis]. / Diagnostiek op prostaatbiopten: onvoldoende verband tussen pathologische uitslag en klinisch beloop voor een individuele prognose.

Since the introduction of serum testing for prostate-specific antigen (PSA) in 1990 for the early detection of prostate cancer, the number of men undergoing a prostate needle-biopsy procedure has increased dramatically. In order to highlight the significance of the various diagnostic outcomes of a prostate needle biopsy, the pathological findings from needle biopsies were compared with those from samples taken during radical prostatectomy and in follow-up biopsies, using data from the 'European randomised screening for prostate cancer' (ERSPC) trial. In men with an elevated PSA value and a benign or negative needle-biopsy result, 10-15% were found to have prostate cancer in follow-up biopsies. In men with a needle-biopsy diagnosis of adenocarcinoma, 29% were found to have questionable histopathological characteristics or minimal cancer that did not require therapy. The incidence of minimal cancer increased to 70% among men with a needle-biopsy diagnosis of focal carcinoma, i.e. a small focus (< 3 mm diameter) of well-differentiated adenocarcinoma, based on one biopsy from a series of six. In men with a needle-biopsy diagnosis of 'suspected malignancy' 36.5% were found to have prostate cancer in follow-up biopsies. In men with a needle-biopsy diagnosis of 'high grade prostatic intra-epithelial neoplasia' 13% were found to have prostate cancer in follow-up biopsies. This percentage was not significantly higher than the percentage of cancers detected after an initially benign biopsy outcome. To avoid over-treatment of a substantial number of men who lack symptoms of prostate cancer but are diagnosed on the basis of biopsy results, it is vital that clinical/pathologic parameters are developed and validated that can help in deciding whether to initiate curative treatment immediately.

Protein kinase G reverses all isoproterenol induced changes of cardiac single L-type calcium channel gating.

OBJECTIVE: cGMP reduces the effect of beta-adrenoceptor agonists on cardiac L-type calcium current by protein kinase G activation. Stimulation of beta-adrenoceptors increases protein kinase A dependent phosphorylation of L-type calcium channels via cAMP. At the single channel level, protein kinase A dependent phosphorylation increases both availability and open probability. The present study investigates how cGMP antagonises protein kinase A induced changes of single L-type calcium channel gating. METHODS: Single L-type calcium channels were recorded in the cell attached configuration of the patch clamp technique in isolated mouse ventricular myocytes. RESULTS: The beta-adrenoceptor agonist isoproterenol (10(-6) M) enhanced single channel peak average current by increasing availability and open probability and decreasing the time constant of long close times. 8-Br-cGMP (10(-3) M) completely reversed these effects. The phosphatase inhibitor okadaic acid (10(-6) M) did not influence the effect of 8-Br-cGMP. The protein kinase G inhibitor Rp-8Br-PET-cGMPS (10(-7) M) abated the effect of 8-Br-cGMP. Activation of protein kinase A by the hydrolysis-resistant cAMP derivative 8-Br-cAMP (10(-3) M) enhanced L-type calcium channel activity like isoproterenol and its effect was also reversed by 8-Br-cGMP. CONCLUSION: 8-Br cGMP diminishes beta-adrenoceptor activation of L-type calcium channels via protein kinase G. It interacts with the beta-adrenoceptor signaling pathway distal of adenylyl cyclase. Our observations suggest that protein kinase G interacts either with protein kinase A or directly with the L-type calcium channel.

Single-channel properties of L-type calcium channels from failing human ventricle.

OBJECTIVE: The aim of our study was to analyse the single-channel properties of L-type calcium channels from failing human heart and to compare them to the respective animal data. Furthermore, we intended to evaluate the feasibility of future single-channel studies on the role of calcium channels in the pathophysiology of heart failure. METHODS: Single L-type calcium channels were recorded in ventricular myocytes from explanted failing human heart, using the cell-attached configuration of the patch-clamp technique. RESULTS: One or more successful registrations of calcium channels could be obtained in 11 of 19 cell isolations. Determination of single-channel conductance yielded a mean value of 16.6 +/- 1.2 pS (70 mM Ba2+ as the charge carrier) under control conditions and 23.7 +/- 2.8 pS in presence of the calcium-channel agonist FPL 64176. The rapid gating process could be described by a C<-->C<-->O gating scheme. Slow gating analysis revealed a highly significant clustering of active and non-active sweeps. CONCLUSION: Single-channel measurements of L-type calcium channels in human failing ventricle are feasible and reproducible despite the varying patient characteristics. Their channel properties are qualitatively comparable to those found in other mammals. Whether there are quantitative differences due to the underlying heart failure can be elucidated in further studies.