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PubMedDate not supplied

Intracellular signaling pathways mediated by the gonadotropin-releasing hormone (GnRH) receptor.

The hypothalamic gonadotropin-releasing hormone (GnRH) is a key regulator of the reproductive system, triggering the synthesis and release of LH and FSH in the pituitary. GnRH transmits its signal via two specific serpentine receptors that belong to the large group of G-protein coupled receptors (GPCRs). Here we review the intracellular signaling pathways mediated by the GnRH receptor (GnRHR). In pituitary-derived alpha T3-1 cells, a widely used model for GnRH action, GnRHR signaling includes activation of mitogen-activated protein kinase (MAPK) cascades, which provide an important link for the transmission of signals from the cell surface to the nucleus and play a role in the regulation of gonadotropin transcription. Activation of ERK--one of the MAPK cascades--by GnRH in these cells depends mainly on the phosphorylation of Raf1 by PKC, supported by a pathway involving c-Src, dynamin, and Ras. On the other hand, the activation of JNK, another MAPK cascade, involves PKC, c-Src, CDC42/Rac1, and probably MEKK1. The GnRHR is also expressed in non-pituitary cells and was found to be involved in the inhibition of cell proliferation in certain cells. Therefore, GnRHR represents a potential target for GnRH-analogs used for cancer treatment. Interestingly, the signaling mechanism of the GnRHR in other cell types significantly differs from that in pituitary cells. Studies conducted in GnRHR-expressing COS7 cells have shown that GnRHR transmits its signals mainly via Gi, EGF receptor, c-Src, and is not dependent on PKC. Understanding the signaling mechanisms elicited by GnRHR can shed light on the mechanism of action of GnRH in pituitary and extra-pituitary tissues.

Animals↗
PubMed1985

Two-dimensional, gray-scale ultrasonography. Applications in canine prostatic disease.

The technique of and general appearance of suprapubic gray-scale prostatic ultrasonography in the dog are described. Using case examples, the various spontaneous diseases of the canine prostate are described and compared to the defined normal appearance of the prostate. An integrated approach to imaging the canine prostate gland is advocated and includes radiographic techniques, specifically distension retrograde urethrocystography. A clinically relevant classification scheme for use with microbiologic, cytologic, and imaging techniques is proposed.

Animals↗
PubMed1986

Canine prostatic diseases.

Prostatic diseases such as benign hyperplasia, prostatic cysts, acute bacterial prostatitis, chronic bacterial prostatitis, prostatic abscessation, and prostatic neoplasia are discussed. Also discussed are diagnostic techniques such as prostatic palpation and massage, evaluation of semen and urethral discharge, and radiography.

Animals↗
PubMed2002

[Prostatic exfoliative cytology obtained from urine samples after massage. Initial results].

INTRODUCTION: The same as the exfoliative cytology is a routine method to diagnose bladder tumour, the prostatic cytology obtained after massage may become a useful procedure to diagnose prostate cancer. OBJECTIVE: To obtain suitable prostatic cytologic material. To establish the role of the exfoliative cytology to diagnose cancer. MATERIAL AND METHODS: We made a prospective longitudinal descriptive study with 60 patients out of 150 (all of them with possible prostate cancer) for two years. We compared cytologic discoveries (urine after massage) with histological parameters (biopsies). RESULTS: When the cytology fulfills a series of requirements (a high number of prostatic cells, anisokariosis and antibodies Ki-67+) and these are compared with the histological data, we obtained a specificity of 100% and a sensibility of 67% for prostatic cancer. With this information the cytology reaches a predictive value of 100% and negative of 92%. CONCLUSIONS: It is possible to obtain prostatic cytologic material in a simple and easy way. The prostatic cytology may become a valid and useful method to diagnose the carcinoma of the prostate. Also this material can be used for multiple diagnostic, follow-up and research procedures.

Adenocarcinoma↗
PubMed2006

[Imaging of normal, hyperplastic and inflammatory prostate gland].

According to Mc Neal, the prostate gland is characterized by three major glandular compartments: the transition zone, the central zone and the peripheral zone. This zonal anatomy can be identified with endorectal sonography and with MRI. With the later, both endorectal or external surface coils can be used. Internal structure of seminal vesicles and vas deferens is better analyzed with MRI than with sonography. Relationship between these elements is important to know, as well as areas of weakness of the prostatic capsule, mainly in the evaluation of cancer extraprostatic extension. Sonography plays a major role in diagnosis, pre-therapeutic evaluation and follow-up of patients with benign prostatic hyperplasia. The role of imaging in inflammatory disorders is more questionable.

Abscess↗
PubMed2006

[Transrectal ultrasound and biopsy of the prostate].

This review describes the transrectal ultrasound (TRUS) features of prostate cancer (PC), discusses the role of TRUS in the detection of PC and defines the modalities of biopsies in patients with suspected PC, particularly concerning prevention of complications, the number of biopsies and the biopsy schemes ensuring an optimal cancer detection rate. TRUS alone has limited potential to identify PC because of frequent multifocality of cancer within the prostate, the variable sonographic appearance of prostatic tumors, the poor specificity of focal US abnormalities, and the substantial percentage of isoechoic PC. Over the past decade, the sextant biopsy technique has emerged as the standard of care in the detection of PC. However, limitations in cancer detection have been appreciated, particularly a false-negative rate approaching 20%. This high failure rate has led investigators to refine biopsy techniques to improve cancer detection and to increase the total number of cores. Currently, recommendations include increasing the biopsy number to a minimum of 10-12 cores, including sampling of the lateral prostate. Refinements in imaging technologies (power Doppler sonography, microbubble intravenous sonographic contrast agents, and MR spectroscopy or dynamic contrast MR imaging) should eventually improve targeting of prostate needle biopsy and reduce false-negative biopsies.

Biopsy↗
PubMed2005

[Mixed endocrine tumors].

Mixed endocrine tumors are tumors composed of at least two distinct tumor populations, one of which is endocrine. Because of their rarity and unusual presentation, endocrine mixed tumors raise many problems of diagnosis, management and therapy. Three main types of endocrine mixed tumors are recognized: The existence of these various types has been confirmed by recent molecular studies, even if the same studies have also shown that the histogenesis of a mixed endocrine tumor cannot be predicted from its histological features. Composite tumors are the less rare mixed tumors. The recent WHO classification recommends to restrict the term of composite endocrine tumor to the epithelial tumors containing at least 30% of obviously tumoral endocrine cells; some authors recommend to use higher thresholds, of at least 50%, in order to avoid overdiagnosis. The endocrine component is usually well differentiated, easily identified by its suggestive histological features; the endocrine nature of tumor cells is confirmed by the immunodetection of specific endocrine and neuro-endocrine markers (such as chromogranin A and synaptophysin). In some cases, the endocrine component is poorly differentiated: the demonstration of neuro-endocrine markers is necessary to confirm the diagnosis. Mixed tumors can occur in every anatomical site; they are more frequent in organs containing endocrine cells in the normal state (especially the digestive tract and the pancreas), but they can also be observed in organs devoid of endocrine cells (such as the mammary gland). The management of mixed endocrine tumors must take into account the more aggressive component. Mixed tumors containing a well differentiated endocrine component and an adenocarcinomatous component are to be treated like adenocarcinomas. Mixed tumors containing a poorly differentiated endocrine component must be considered as poorly differentiated endocrine carcinomas.

Colonic Neoplasms↗
PubMed1979

[The cytologic differentiation of prostatis (author's transl)].

INTRODUCTION: Cytologists are often confronted with unexpected prostatitis in aspiration biopsy smears, because clinically prostatitis may lead to suspicious induration of the prostate similar to carcinoma and therefore subject to diagnostic biopsy. The question is whether cytodiagnosis is a reliable method for the exact morphologic diagnosis of prostatitis. The following paper attempts to answer this question. MATERIAL AND METHODS: The basis of our cytologic differentiation of prostatitis was a series of 129 cases of prostatitis in 664 aspiration biopsies according to Franzén. In 82 of these 129 cases, we had simultaneously performed a transrectal needle punch biopsy, which allowed a diagnostic comparison between the cytologic and histologic diagnosis with special reference to the reliability of cytology. Epithelial atypias were classified into 4 grades: Grade 1: No atypia; Grade 2: Slight atypia; Grade 3: Marked atypia; Grade 4: Malignant epithelium. Cytomorphologic characteristics of each grade are described. RESULTS: We found 6 different types in 4 main groups of prostatitis: 1. Acute prostatitis, purulent and abscessing types. 2. Chronic prostatitis. 3. Chronic relapsing prostatitis. 4. Granulomatous prostatitis, non specific and specific types. All types showed classic cytomorphologic inflammatory criteria. Marked atypias were found in group 3 and 4. Differential diagnosis with respect to carcinoma is not difficult, however, because marked atypias in these groups of prostatitis almost always appear focally. The diagnostic agreement between cytology and histology in 82 cases was found to be 87,6%. DISCUSSION: Our results showed that prostatis may be adequately diagnosed with cytology and may be differentiated into 6 different types. However, differentiation between periductal and interstitial forms of chronic prostatitis is impossible with cytology. Reliable cytodiagnosis of prostatitis requires a good aspiration smear, so that at least one half of slide is covered with material from the prostate. Furthermore, epithelial atypias must be present to prove the presence of prostatitis. Because of the good reliability of the cytologic differentiation of prostatitis, aspiration biopsy may be a valuable aid to the clinician in the primary diagnosis of prostatitis, especially the chronic type, which currently is sometimes uncertain.

Acute Disease↗
PubMed2000

Clinical evaluation and verification of the hyperthermia treatment planning system hyperplan.

PURPOSE: A prototype of the hyperthermia treatment planning system (HTPS) HyperPlan for the SIGMA-60 applicator (BSD Medical Corp., Salt Lake City, Utah, USA) has been evaluated with respect to clinical practicability and correctness. MATERIALS AND METHODS: HyperPlan modules extract tissue boundaries from computed tomography (CT) images to generate regular and tetrahedral grids as patient models, to calculate electric field (E-field) distributions, and to visualize three-dimensional data sets. The finite difference time-domain (FDTD) method is applied to calculate the specific absorption rate (SAR) inside the patient. Temperature distributions are calculated by a finite-element code and can be optimized. HyperPlan was tested on 6 patients with pelvic tumors. For verification, measured SAR values were compared with calculated SAR values. Furthermore, intracorporeal E-field scans were performed and compared with calculated profiles. RESULTS: The HTPS can be applied under clinical conditions. Measured absolute SAR (in W/kg), as well as relative E-field scans, correlated well with calculated values (+/-20%) using the contour-based FDTD method. Values calculated by applying the FDTD method directly on the voxel (CT) grid, were less well correlated with measured data. CONCLUSION: The HyperPlan system proved to be clinically feasible, and the results were quantitatively and qualitatively verified for the contour-based FDTD method.

Algorithms↗
PubMed2000

Towards multidimensional radiotherapy (MD-CRT): biological imaging and biological conformality.

PURPOSE: The goals of this study were to survey and summarize the advances in imaging that have potential applications in radiation oncology, and to explore the concept of integrating physical and biological conformality in multidimensional conformal radiotherapy (MD-CRT). METHODS AND MATERIALS: The advances in three-dimensional conformal radiotherapy (3D-CRT) have greatly improved the physical conformality of treatment planning and delivery. The development of intensity-modulated radiotherapy (IMRT) has provided the "dose painting" or "dose sculpting" ability to further customize the delivered dose distribution. The improved capabilities of nuclear magnetic resonance imaging and spectroscopy, and of positron emission tomography, are beginning to provide physiological and functional information about the tumor and its surroundings. In addition, molecular imaging promises to reveal tumor biology at the genotype and phenotype level. These developments converge to provide significant opportunities for enhancing the success of radiotherapy. RESULTS: The ability of IMRT to deliver nonuniform dose patterns by design brings to fore the question of how to "dose paint" and "dose sculpt", leading to the suggestion that "biological" images may be of assistance. In contrast to the conventional radiological images that primarily provide anatomical information, biological images reveal metabolic, functional, physiological, genotypic, and phenotypic data. Important for radiotherapy, the new and noninvasive imaging methods may yield three-dimensional radiobiological information. Studies are urgently needed to identify genotypes and phenotypes that affect radiosensitivity, and to devise methods to image them noninvasively. Incremental to the concept of gross, clinical, and planning target volumes (GTV, CTV, and PTV), we propose the concept of "biological target volume" (BTV) and hypothesize that BTV can be derived from biological images and that their use may incrementally improve target delineation and dose delivery. We emphasize, however, that much basic research and clinical studies are needed before this potential can be realized. CONCLUSIONS: Whereas IMRT may have initiated the beginning of the end relative to physical conformality in radiotherapy, biological imaging may launch the beginning of a new era of biological conformality. In combination, these approaches constitute MD-CRT that may further improve the efficacy of cancer radiotherapy in the new millennium.

Fluorodeoxyglucose F18↗