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Biomedical subjects

H Klocker

Publications and source records attributed to H Klocker.

At least 37 records · Page 2Linked to original sources
PubMed2000

Peptide YY-2 (PYY2) and pancreatic polypeptide-2 (PPY2): species-specific evolution of novel members of the neuropeptide Y gene family.

Several gene duplication events have led to the creation of at least five distinct members of the neuropeptide Y gene family. We now reveal that the most recent of these events, involving the PYY-PPY gene cluster on chromosome 17q21.1, has led to the creation of novel PYY- and PP-like genes on chromosome 17q11 in the human genome. Sequence analysis of the novel human PYY2 and PPY2 genes shows an extensive homology to the peptide YY-pancreatic polypeptide genes, at the level of gene structure, nucleotide sequence, and primary amino acid sequence. The extremely high degree of homology between the PYY-PPY and the PYY2-PPY2 gene clusters, in both coding regions and especially noncoding regions, suggests that the PYY2 and PPY2 genes have arisen by a very recent gene duplication. Similar gene duplication events of the PYY-PPY gene cluster have also occurred in other species, including cow and baboon, but have not been confirmed in the rat and mouse genomes. Interestingly, despite the greater than 92% nucleotide sequence identity between these new genes, a few specific mutations have resulted in significantly altered peptide sequences. These altered sequences are accompanied by acquisition of new functions apparently unrelated to the neurotransmitter/endocrine role of PYY and PPY, as demonstrated by the major involvement of bovine PYY2, also known as seminal plasmin, in the fertilization process.

Amino Acid Sequence↗
PubMed2000

[Long-term results of laparoscopic partial posterior fundoplication in patients with esophageal reflux and disorders of esophageal peristalsis].

BACKGROUND: Gastrosophageal reflux disease (GERD) of long duration is frequently associated with impaired esophageal body motility. This condition has been considered unsuitable for antireflux surgery. METHODS: In order to investigate the outcome of antireflux surgery in the presence of impaired esophageal peristalsis, we studied 67 consecutive GERD patients with poor esophageal body function who underwent laparoscopic partial posterior fundoplication. A standardized questionnaire, upper GI endoscopy, esophageal manometry and 24-hour pH monitoring were performed preoperatively and at a median of 28 months (range, 6-54 months) postoperatively. Esophageal motility was analyzed for contraction amplitudes in the distal two thirds of the esophagus (level 3, 4, and 5), frequency of peristaltic, simultaneous and interrupted waves and total number of defective propagations. In addition, parameters defining the function of the lower esophageal sphincter (LES) were-evaluated. RESULTS: Following antireflux surgery 65 patients (97%) were free of heartburn and regurgitation and had no esophagitis on endoscopy, confirmed by histology. The rate of dysphagia was reduced from 49% preoperatively to 9% postoperatively (p < 0.001). There was significant improvement in esophageal peristalsis after the antireflux procedure. The median DeMeester reflux score was reduced from 33.3 to 1.1 (p < 0.001). Lower esophageal sphincter pressure and intra-abdominal length were normal after surgery. CONCLUSIONS: Partial posterior fundoplication provides an effective antireflux barrier in patients with impaired esophageal body motility in the long term. Postoperative dysphagia is avoided by improving esophageal body function.

Adolescent↗
PubMed2000

Immunohistochemical localization of interleukin-6 and its receptor in benign, premalignant and malignant prostate tissue.

Interleukin-6 (IL-6) is a pleiotropic cytokine that interacts with its receptor in prostate cells, thus regulating proliferative response and differentiation. It also activates the human androgen receptor in prostate cancer cell lines. In order to assess the significance of these findings in vivo, the expression of key elements of the IL-6 signalling pathway, IL-6 and its receptor, was investigated in tissue samples obtained on radical prostatectomy from prostate cancer patients. IL-6 immunohistochemistry was performed on 17 frozen prostate cancer specimens. IL-6 receptor immunostaining was evaluated in 21 paraffin-embedded prostate tumour specimens. In both groups, adjacent areas of high-grade prostatic intraepithelial neoplasia and benign tissue were also investigated. In benign prostatic epithelium, IL-6 was localized predominantly in basal cells, whereas in prostate cancer tissues more IL-6-positive glandular cells were identified. No IL-6 expression was detected in stromal cells on immunohistochemistry, although IL-6 protein was measured in the supernatants obtained from cultured stromal cells by ELISA. IL-6 receptor was expressed in benign prostatic tissue in both epithelial and stromal cells. Furthermore, IL-6 receptor expression was observed in all tumour specimens investigated and the majority of Gleason patterns analysed had more than 50% of cells showing a positive reaction. IL-6 and IL-6 receptor expression patterns in high-grade prostatic intraepithelial neoplasia lesions were similar to those observed in tumour tissues. Taken together, the results of the present study imply that there are paracrine and autocrine IL-6 loops in benign and neoplastic prostate.

Adenocarcinoma↗
PubMed2000

Effects of alpha1-adrenoceptor antagonists on cultured prostatic smooth muscle cells.

BACKGROUND: alpha1-adrenoceptor (alpha1-AR) antagonists, used to relieve the lower tract urinary symptoms (LUTS) in benign prostate hyperplasia (BPH) patients, are thought to act in inhibiting the contraction of stromal smooth muscle. An attempt was made using new technology to visualize and quantify the effect of alpha1-AR antagonists in a cell culture model of prostatic smooth muscle cells (SMC). METHODS: Prostatic smooth muscle cells cultured from human prostate tissue were treated with alpha1-AR agonists and antagonists. The effects on cell growth, cell contraction, differentiation status, and apoptosis were determined by means of an MTT cell viability assay, time-lapse video microscopy, RT-PCR analysis, and FACS analysis of annexin V/propidium iodide-stained cells, respectively. RESULTS: Prostatic smooth muscle cells derived from prostate tissue expressed SMC-specific markers. They showed spontaneous contractions, and phenylephrine increased the percentage of contracting cells by 3-fold. alpha1-AR antagonists inhibited spontaneous as well as phenylephrine-induced contractions. Long-term treatment with doxazosin induced differentiation tended towards a contractile phenotype, as indicated by an increase of the ratio of smooth muscle heavy chain myosin subtypes SM2/SM1. There was, however, no effect on cell growth. High concentrations of antagonist (100 microM) induced apoptosis in about 80% of the treated SMC. This effect was not cell-type-specific and was also seen in skin fibroblasts and immortalized prostate epithelial cells. CONCLUSION: In an easy-to-handle cell culture model of prostatic smooth muscle cells, the effects of alpha1-AR antagonists on cell contraction, growth, and differentiation can be investigated. The results indicate that in addition to inhibition of cell contraction, alpha1-AR antagonists have the potential to induce apoptosis.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed2000

Androgen receptor--an update of mechanisms of action in prostate cancer.

Androgen receptor (AR), a key nuclear transcription factor in the prostate gland, is expressed in all histological types and stages of prostate cancer. The AR regulates proliferation of prostate cancer cells by stimulation of cyclin-dependent kinases. However, in some prostate tumors AR stimulates expression of cell cycle inhibitors, thus leading to down-regulation of cellular proliferation. Androgens, by activation of the AR, control differentiation of prostate cells and synthesis of neutral lipids. There are several mechanisms by which prostate cancer cells adapt to an environment with low androgen supply during endocrine therapy. The AR expression and activity increase in several cell lines that are used as an in vitro model for monitoring changes during long-term androgen ablation. Mutant ARs are of importance for monitoring the natural course of the disease and for determining the response to anti-androgens in metastatic lesions from prostatic carcinoma. In addition, AR activity is up-regulated by various stimulators of intracellular protein kinases. Current research efforts are focused on elucidation of function of AR coregulatory proteins, coactivators and corepressors. Their inappropriate expression and/or function might critically influence cellular events in advanced carcinoma of the prostate. It is hoped that information on these coregulatory proteins will serve as a basis for a more efficient pharmacological inhibition of the AR in advanced carcinoma of the prostate.

Animals↗
PubMed2000

An in vitro model for videoimaging of human bladder smooth muscle cell contractions.

Knowledge regarding human bladder smooth muscle cell (SMC) physiology is very limited. Only a few specific medical therapies for bladder disorders have therefore been established. The objective of this study was to develop a model for videomicroscopy of bladder SMC contractions. Cells were isolated from human cystoprostatectomy specimens and cultured in a modified EMEM medium. These cells were identified as SMCs by means of immunohistochemistry. For videomicroscopy, the culture flasks were coated with a viscous agent to allow cell contraction. Contractions were visualized by means of a cell culture microscope with a time-lapse videosystem. For cholinergic stimulation of the cells, acetylcholine, in concentrations ranging from 100 microM to 10 mM, was applied. The percentage of contracting cells within the observation field was evaluated for quantitative analysis. In control experiments without contractile stimulant 6% of the cells were observed to contract. Stimulation with acetylcholine induced a significant dose-dependent increase to 47% in contracting cells. These results demonstrated that videomicroscopy is an appropriate tool to investigate the contraction mechanisms of bladder SMCs. This model offers the possibility of studying drug effects on the human detrusor in vitro.

Acetylcholine↗
PubMed2000

Reconstruction of the lower urinary tract using autologous muscle transfer and cell seeding: current status and future perspectives.

Functioning free-muscle transfer has established itself for the treatment of skeletal muscle deficiency over the last two decades. The capability of skeletal muscle to empty a spherical reservoir has been shown to be lessened if the muscle has contracted due to dissection. Currently there is no established curative treatment for bladder acontractility. Experimental data and preliminary clinical results have shown that innervated free latissimus dorsi muscle (LD) may serve as a substitute for a dysfunctional detrusor. In a clinical protocol, latissimus dorsi detrusor myoplasty (LDDM) was applied in 11 patients (age 9-68 years) with bladder acontractility due to spinal cord injury (seven patients), congenital malformations (two patients), detrusor myopathy (one patient), and idiopathic causes (one patient) who had required catheterization for bladder emptying for a minimum of 2 years. In all, 10 of 11 patients were capable of voiding volitionally, with eight of them no longer requiring catheterization, throughout the follow-up period of 12-46 months. Transplanted LD activity was confirmed by ultrasonography and flow-mode computerized tomography. It can thus be concluded that emptying of the bladder can be induced through the contractility of reinnervated free LD that has been wrapped around the bladder. An innervated free-LD flap does not undergo the severe muscle fibrosis, contracture, and atrophy that occur after transfer of completely or partially denervated pedicled muscle. Apart from the restoration of deficient detrusor function, microneurovascular transfer of a free-LD flap may be combined with tissue engineering to serve as a basis for bladder augmentation and substitution.

Adolescent↗
PubMed2000

Prostate cancer screening in the Tyrol, Austria: experience and results.

This article summarises the experience and results of different prostate carcinoma screening projects using total prostate specific antigen (PSA) and per cent free PSA as the initial test. Of the 21078 volunteers 1618 (8%) had elevated PSA levels. Of these men 778 (48%) underwent biopsies; 197 (25%) biopsies were positive for prostate carcinoma and 135 (17%) underwent radical prostatectomy. 95 were found to be organ-confined. A PSA cut-off of 2.5 ng/ml in men aged 45-49 years and of 3.5 ng/ml in men aged 50-59 years resulted in an 8% increase in the detection rate of organ-confined disease. 284/2272 men (13%) had elevated PSA levels and prostate carcinoma was detected in 62 men (3%). All patients underwent radical prostatectomy and histological examination revealed organ-confined tumour in all but 8 men. 98/340 men (29%) had biopsies positive for carcinoma; 28 of these patients (29%) had carcinoma that originated in the transition zone only. In the retrospective study, receiver operating characteristic curve analysis showed that by using a per cent free PSA of less than 18% as a biopsy criterion, 37% of the negative biopsies could be eliminated although 94% of all carcinomas would still be detected. In the first prospective study, 106/158 men (67%) with elevated PSA levels below 10.0 ng/ml were further evaluated and 37 (35%) prostate carcinomas were detected. By using a per cent free PSA of <22% as a biopsy criterion, 30% of the negative biopsies could be eliminated although 98% of the carcinomas would still be detected. In the second prospective study, 120/465 men (26%) with total PSA levels between 1.25 and 6.49 ng/ml and a per cent free PSA<18% were further evaluated and 27 (23%) were found to have prostate carcinomas. Receiver operating characteristic curve analysis for PSA transition zone (TZ) density showed that by using a PSA transition zone density of >22 ng/ml/cc as a biopsy criterion, 24.4% of negative biopsies could be avoided without missing a single carcinoma. In the prescreening era the incidence of T1a Grade 1 and 2 carcinomas was 3.1% and the incidence of T1a and T1b Grade 3 carcinoma was 2.3% whereas in the years after the establishment of PSA-based screening the incidence was 4.6 and 1.03% respectively. The rate of organ-confined tumours increased from 28.7% in 1993 to 65.7% in 1997. In this evaluation a new approach, to proceed with a prostate biopsy based upon the individual risk of having prostate cancer rather than a single PSA cut-off point was developed. High total PSA levels, PSA density and PSA transition zone density correlated significantly with high Gleason scores, capsular penetration, a high percentage of cancer in the prostatectomy specimen and a high cancer volume. In this evaluation all of the 95 patients with PSA levels below 3.99 ng/ml who underwent radical prostatectomy showed clinically significant, organ-confined prostate cancer with negative surgical margins. The results of this evaluation suggest that older men have larger tumour volumes compared with younger men with the same PSA levels. These data suggest that PSA-based screening with low PSA cut-off values increase the detection rate of clinically significant, organ confined and potentially curable prostate cancer. Per cent free PSA and PSA transition zone density provide an additional diagnostic benefit over total PSA.

Age Distribution↗
PubMed2000

Inhibition of LncaP prostate cancer cells by means of androgen receptor antisense oligonucleotides.

Currently available methods for treatment of human prostatic carcinoma aim to inactivate the androgen receptor (AR) by androgen deprivation or blockade with anti-androgens. Failure of endocrine therapy and tumor progression is characterized by androgen-independent growth despite high levels of AR expression in metastatic disease. We inhibited AR expression in LNCaP prostate tumor cells by using antisense AR oligodeoxynucleotides (ODNs) and explored whether antisense AR treatment would be conceivable as a therapy for advanced prostate cancer. Among the various AR antisense ODNs tested, a 15-base ODN targeting the CAG repeats encoding the poly-glutamine region of the AR (as750/15) was found to be most effective. Treatment of LNCaP cells with as750/15 reduced AR expression to approximately 2% within 24 hours compared with mock-treated controls. AR down-regulation resulted in significant cell growth inhibition, strongly reduced secretion of the androgen-regulated prostate-specific antigen, reduction of epidermal growth factor receptor expression, and an increase in apoptotic cells. Mis-sense and mismatched control ODNs had no or only slight effects. Antisense inhibition was also very efficient in LNCaP-abl cells, a subline established after long-term androgen ablation of LNCaP cells, resulting in inhibition of AR expression and cell proliferation that was similar to that seen for parental LNCaP cells. This study shows that inhibition of AR expression by antisense AR ODNs may be a promising new approach for treatment of advanced human prostate cancer.

Apoptosis↗
PubMed2000

Androgen receptor protein is down-regulated by basic fibroblast growth factor in prostate cancer cells.

Interactions between polypeptide growth factors and the androgen receptor (AR) are important for regulation of cellular events in carcinoma of the prostate. Basic fibroblast growth factor (bFGF), the prototype of heparin-binding growth factors, and the AR are commonly expressed in prostate cancer. bFGF diminished prostate-specific antigen protein in the supernatants of androgen-stimulated human prostate cancer cells LNCaP by 80%. In the present study, we asked whether the bFGF effect on prostate-specific antigen is preceded by action on AR expression. LNCaP cells were treated with bFGF and AR protein expression was determined by immunoblotting and ligand binding assay. bFGF down-regulated AR protein in a dose-dependent manner showing a maximal effect at 50 ng ml(-1) both in the presence or absence of dihydrotestosterone. Down-regulation of AR protein expression occurred already after 8 h of bFGF treatment and a maximal inhibition was observed 24 h after addition of bFGF to culture media. As AR expression can be reduced by an increase in intracellular calcium levels, we investigated whether the bFGF effect on AR protein is mediated by this mechanism. Calcium release from intracellular stores and store-operated calcium influx after treatment with either bFGF or calcium ionophore A 23187 were measured by single cell fluorescence technique. The ionophore A 23187 was able to induce calcium influx and an increase in cytoplasmic calcium concentration in LNCaP cells. In contrast, bFGF was incapable of eliciting a similar effect. In contrast to AR protein, AR mRNA levels were not affected by bFGF as shown by semiquantitative reverse transcription polymerase chain reaction. In summary, these studies show that bFGF is a potent negative regulator of AR protein expression in the human prostate cancer cell line LNCaP.

Calcium↗
PubMed2000

Effect of heat exposure on viability and contractility of cultured prostatic stromal cells.

OBJECTIVES: Different thermotherapeutic modalities such as transurethral microwave therapy or transurethral needle ablation have been developed to provide effective alternatives to surgical management of benign prostate hyperplasia (BPH). The mechanisms of thermotherapy, however, are not completely understood. We developed a model to investigate the effects of heat application on stromal cell viability and contractility. METHODS: Cells isolated from prostatectomy and cystoprostatectomy specimens were cultured in a selective medium. Temperatures ranging from 37 to 50 degrees C were applied for 1 h. Cell contraction was visualized by means of a cell culture microscope equipped with a time-lapse video system. For quantitative analysis, the percentage of contracting cells was evaluated; 10 microM of phenylephrine were applied for adrenergic stimulation of the cells. RESULTS: On immunohistochemistry and phase-contrast microscopy, these cells were identified as prostatic myofibroblasts. Incubation at 50 degrees C for 1 h in vitro induced immediate death of all cells, whereas at 45 degrees C all cells survived. At 37 degrees C 55% of the cells were seen to contract after addition of phenylephrine. Immediately after incubation at 45 degrees C contraction rate decreased to 29%, but returned to 46% 1 day later. CONCLUSIONS: With this model, it is possible to study the mechanisms of thermotherapy in vitro. The results suggest that the effects of thermotherapy are due to the induction of cell death rather than to reduced stromal cell contractility. Furthermore, the data show that treatment is probably only successful if temperatures in excess of 50 degrees C are maintained.

Cells, Cultured↗
PubMed2000

Dihydrotestosterone and the concept of 5alpha-reductase inhibition in human benign prostatic hyperplasia.

OBJECTIVE: The development of the human benign prostatic hyperplasia clearly requires a combination of testicular androgens and aging. Although the role of androgens as the causative factor for human benign prostatic hyperplasia is debated, they undoubtedly have at least a permissive role. The principal prostatic androgen is dihydrotestosterone (DHT). Although not elevated in human benign prostatic hyperplasia, DHT levels in the prostate remain at a normal level with aging, despite a decrease in the plasma testosterone. RESULTS: DHT is generated by reduction of testosterone. Two isoenzymes of 5alpha-reductase have been discovered. Type 1 is present in most tissues of the body where 5alpha-reductase is expressed and is the dominant form in sebaceous glands. Type2 5alpha-reductase is the dominant isoenzyme in genital tissues, including the prostate. Finasteride is a 5alpha-reductase inhibitor that has been used for the treatment of benign prostatic hyperplasia and male-pattern baldness. At doses used clinically, its major effect is through suppression of type 2 5alpha-reductase, because it has a much lower affinity for the type 1 isoenzyme. Finasteride suppresses DHT by about 70% in serum and by as much as 85-90% in the prostate. The remaining DHT in the prostate is likely to be the result of type 1 5alpha-reductase. Suppression of both 5alpha-reductase isoenzymes with GI198745 result in greater and more consistent suppression of serum dihydrotestosterone than that observed with a selective inhibitor of type 2 5alpha-reductase. Physiological and clinical studies comparing dual 5alpha-reductase inhibitors, such as GI198745, with selective type 2, such as finasteride, will be needed to determine the clinical relevance of type 1 5alpha-reductase within the prostate. Two large international multicenter, phase III trials have been published documenting the safety and efficacy of finasteride in the treatment of human benign prostatic hyperplasia. Combining these two studies, randomized, controlled data are available for 12 months. Noncontrolled extension of these data from a subset of patients, who elected to continue drug treatment for 3, 4 or 5 years, are also available. Long-term medical therapy with finasteride can reduce clinically significant endpoints such as acute urinary retention or surgery. According to the meta-analysis of six randomised clinical trial with finasteride, finasteride is most effective in men with large prostates. A more effective dual inhibitor of type 1 and 2 human 5alpha-reductase may lower circulating DHT to a greater extent than finasteride and show advantages in the treatment of human benign prostatic hyperplasia and other disease states that depend on DHT. CONCLUSION: Clinical evaluation of potent dual 5alpha-reductase inhibitors may help define the relative roles of human type 1 and 2 5alpha-reductase in the pathophysiology of benign prostatic hyperplasia and other androgen-dependent diseases.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2000

Antagonist/agonist balance of the nonsteroidal antiandrogen bicalutamide (Casodex) in a new prostate cancer model.

Androgen ablation is standard therapy for advanced prostate carcinoma. It can be administered either as a monotherapy or as a combined androgen blockade. In the present study we have investigated molecular mechanisms which are responsible for the development of resistance to therapy in advanced prostate cancer. For this purpose, we have cultured LNCaP cells in steroid-depleted medium for 1 year. The newly generated subline LNCaP-abl was characterized. In early passages (<75) LNCaP-abl cells showed a biphasic hypersensitive response to androgenic stimulation. Passages later than 75 are inhibited by androgen. Proliferation of LNCaP-abl cells was stimulated by the pure nonsteroidal antiandrogen bicalutamide (Casodex). To improve our understanding of changes which occur during intermittent androgen ablation, we have generated the sublines LNCaP-R (reversal; cultured with fetal calf serum) and LNCaP-RA (reversal and androgen; cultured with fetal calf serum and androgen) from LNCaP-abl cells. In both cell lines an increase of the basal proliferation rate was observed. Androgen receptor expression in LNCaP-abl cells was 4-fold higher than that in parental LNCaP cells (4.7 vs. 1.2 fmol/microg protein). Androgen receptor content in LNCaP-R cells was 1.8 fmol/microg protein and in LNCaP-RA cells 1.0 fmol/microg protein. The basal androgen receptor activity was 30-fold higher in LNCaP-abl cells compared to that in parental LNCaP cells. This basal activity was reduced in LNCaP-RA cells. Both androgen and the nonsteroidal androgen receptor antagonist hydroxyflutamide induced a 2- to 4-fold higher activation of androgen receptor in LNCaP-abl than in LNCaP cells. There was a switch from an antagonist to an agonist of the nonsteroidal antiandrogen bicalutamide (Casodex) in LNCaP-abl cells. Antagonistic properties of this androgen receptor blocker were again observed in both sublines (LNCaP-R and LNCaP-RA) derived from LNCaP-abl cells. In concordance with proliferation data in vitro, growth of LNCaP-abl cells in nude mice was stimulated by bicalutamide. In contrast, supplementation of androgen led to inhibition of proliferation of these cells. The present study provides new information that is useful for a better understanding of therapy-refractory prostate cancer. It is also important for the development of new therapy strategies for advanced carcinoma of the prostate.

Androgen Antagonists↗
PubMed2000

Elevated levels of serum secretoneurin in patients with therapy resistant carcinoma of the prostate.

PURPOSE: The majority of prostate cancers show some degree of neuroendocrine differentiation. It was previously demonstrated that chromogranin A, a constituent of large dense core vesicles of neuroendocrine cells, is frequently elevated in patients with metastatic prostate cancer. We evaluate the expression of secretoneurin, which is generated by proteolytic processing of secretogranin II (chromogranin C), in patients with prostate disease. MATERIALS AND METHODS: Secretoneurin was measured in sera of 16 healthy men whose blood was drawn for prostate cancer screening (controls), and in 9 patients with prostatitis, 19 with benign prostate hyperplasia and 54 with prostate cancer detected by radioimmunoassay. Therapy resistant disease (clinical stage D3) was noted in 20 prostate cancer cases. Serum prostate specific antigen was measured in all patients and controls. In addition, chromogranin A, prostate acid phosphatase and interleukin-6 were determined in patients with D3 prostate cancer. Molecular properties of secretoneurin immunoreactivity were analyzed by gel filtration chromatography followed by radioimmunoassay. RESULTS: Mean secretoneurin was 58.9+/-8 fmol./ml. in patients with therapy resistant prostate cancer. Levels were significantly higher than those measured in sera from controls and patients with prostatitis, benign prostatic hyperplasia and pT2 or pT3 prostate cancer. There was a statistically significant correlation between secretoneurin and chromogranin A in patients with endocrine therapy failure (r = 0.543, p<0.05). There was no correlation between serum secretoneurin and prostate specific antigen, prostate acid phosphatase or interleukin-6. Gel filtration chromatography analysis of sera of 3 patients with D3 prostate cancer revealed a peak of secretoneurin immunoreactivity where intact secretoneurin elutes, thus showing that the processed peptide is circulating in the blood. CONCLUSIONS: Secretoneurin is elevated in sera of patients with endocrine therapy refractory prostate cancer. Our results support the concept that neuroendocrine differentiation is associated with prostate cancer progression.

Adult↗
PubMed1999

Rapid signalling by androgen receptor in prostate cancer cells.

Androgens are important growth regulators in prostate cancer. Their known mode of action in target cells requires binding to a cytoplasmic androgen receptor followed by a nuclear translocation event and modulation of the expression of specific genes. Here, we report another mode of action of this receptor. Treatment of androgen responsive prostate cancer cells with dihydrotestosterone leads to a rapid and reversible activation of mitogen-activated protein kinases MAPKs (also called extracellular signal-regulated kinases or Erks). Transient transfection assays demonstrated that the androgen receptor-mediated activation of MAP kinase results in enhanced activity of the transcription factor Elk-1. This action of the androgen receptor differs from its known transcriptional activity since it is rapid and insensitive to androgen antagonists such as hydroxyflutamide or casodex. Biochemical studies as well as analyses with dominant negative mutants showed the involvement of kinases such as MAPK/Erk kinase, phosphatidyl-inositol 3-kinase and protein kinase C in the androgen receptor-mediated activation of MAP kinase. These results demonstrate a novel regulatory action of the androgen receptor and prove that in addition to its known transcriptional effects, it also uses non-conventional means to modulate several cellular signalling processes.

Adenocarcinoma↗
PubMed1999

Correlation between preoperative predictors and pathologic features in radical prostatectomy specimens in PSA-based screening.

BACKGROUND: Measurement of percent free prostate-specific antigen (PSA), PSA density, and PSA-transition zone density (PSA-TZ density) in addition to total PSA is known to improve the specificity of PSA-based prostate cancer screening. We evaluated the ability of total PSA, percent free PSA, PSA density, and PSA-TZ density to predict pathologic features in radical prostatectomy specimens. METHODS: The levels of total PSA, percent free PSA, PSA density, and PSA-TZ density assessed prior to the diagnosis of prostate cancer were correlated with the pathologic findings in 102 prostate glands with cancer obtained at radical prostatectomy. The entire organs were examined histologically; Pearson correlation coefficients were used for statistical analysis. RESULTS: High levels of total PSA, PSA density, and PSA-TZ density correlated significantly with capsular penetration, high Gleason scores, and large cancer volumes in the prostatectomy specimens. Free PSA was found to correlate well with high Gleason scores, high percentages of cancer, and large cancer volumes, but not with capsular penetration. The four parameters were evaluated by means of logistic regression, which showed that only percent free PSA and total PSA were significant predictors of Gleason scores > or =7 and cancer volumes > or =0.5 cc. With regard to clinically insignificant cancers, only percent free PSA and the Gleason score obtained at biopsy were significant predictors. CONCLUSIONS: In men whose prostate cancers are detected by PSA-based screening, high total PSA levels in combination with low percent free PSA levels are suggestive of a potentially more aggressive type of prostate cancer. This may help both patient and clinician in selecting the most appropriate therapeutic approach.

Adult↗
PubMed1999

Modulation of the differentiation status of cultured prostatic smooth muscle cells by an alpha1-adrenergic receptor antagonist.

BACKGROUND: Prostatic stromal cells are believed to be a key factor in the pathogenesis of benign prostatic hyperplasia (BPH). The effect of phenylephrine, an alpha1-adrenergic receptor agonist, and doxazosin, an alpha1-adrenergic receptor-specific antagonist, on the expression of smooth muscle myosin-heavy-chain isotypes SM-1 and SM-2 was tested in an in vitro model of prostatic smooth muscle cells (SMC). METHODS: Primary prostatic stromal cells, grown in SMC-specific medium, were treated with 10 microM of phenylephrine or 1 microM of doxazosin or a combination of both. SM-2 to SM-1 mRNA ratios and expression of alpha1-adrenergic receptor subtypes were determined by means of reverse transcriptase polymerase chain reaction (RT-PCR) techniques. Cell growth was measured by a cell viability assay. RESULTS: SM-1 mRNA and only very low levels of SM-2 mRNA were detected in prostatic SMC cultures grown for 4 days in a serum-free base medium. After 6 days of treatment, SM-2 expression increased, highest in the doxazosin-treated cultures. In comparison to unstimulated cells, a statistically significant 10-fold increase of the SM-2:SM-1 ratio was measured in doxazosin-treated cultures. Analysis of alpha1-adrenergic receptor subtype expression revealed the presence of mRNAs of subtypes 1d and 1b mRNAs. Subtype 1a was not expressed. Phenylephrine and doxazosin showed no significant effect on cell proliferation and on alpha1d-adrenergic receptor expression. CONCLUSIONS: SMC can differentiate from a proliferative to a contractile phenotype, which is accompanied by increased expression of isotope 2 of smooth muscle myosin heavy chain. Our results suggest that doxazosin seems to have a long-term effect on the differentiation of prostatic stromal cells, indicating that alpha1-adrenergic receptor antagonists do not act solely on SMC contractility.

Adrenergic alpha-1 Receptor Agonists↗