Robert S. Schenken

Bio: Robert S. Schenken is an academic researcher from University of Texas Health Science Center at San Antonio. The author has contributed to research in topics: Mesothelium & Peritoneum. The author has an hindex of 23, co-authored 39 publications receiving 3761 citations. Previous affiliations of Robert S. Schenken include New York Methodist Hospital & Murphy Oil.

Proliferating cell nuclear antigen marks the initiation of follicular growth in the rat.

Abstract: Despite expanding knowledge on the kinetic aspects of folliculogenesis, the question of what initiates follicle growth remains unanswered. Efforts to solve this problem have been thwarted by the absence of sensitive markers to identify the onset of follicular growth. In this study, we determined whether increased proliferating cell nuclear antigen (PCNA) correlates with initiation of follicle growth and might therefore be useful for studying early events in this process. Paraffin sections of ovaries from cycling adult rats, prepubertal eCG+hCG-primed rats, and prepubertal control rats were processed for immunocytochemistry by use of a PCNA primary antibody. In primordial follicles, neither granulosa cells nor oocytes stained for PCNA. PCNA immunoreactivity coincided with the earliest sign of follicle growth, appearing in pregranulosa cells of early primary follicles just beginning to grow. In all primary follicles, some granulosa cells were PCNA-positive. PCNA immunoreactivity in oocytes first appeared in primary follicles, preceding oocyte enlargement. In preantral and antral follicles, granulosa cell PCNA staining was uniform throughout the granulosa cell layers. Oocytes were positive for PCNA in both preantral and antral follicles. PCNA expression diminished in atretic follicles. In CL, granulosa cell PCNA expression was also decreased. Theca cell PCNA expression was first evident in the transitional follicle (1-2-layer granulosa cells) and was present in all stages thereafter. The pattern of PCNA expression did not differ among adult cycling, prepubertal eCG+hCG-stimulated, and control rat ovaries.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical practice. endometriosis

Abstract: A healthy 25-year-old woman presents with worsening dysmenorrhea, pain of recent onset in the left lower quadrant, and dyspareunia She has regular menstrual cycles, and her last menstrual period was 3 weeks before presentation How should this patient be evaluated and treated?

ESHRE guideline for the diagnosis and treatment of endometriosis

Abstract: The objective was to develop recommendations for the diagnosis and treatment of endometriosis and its associated symptoms. A working group was convened comprised of practising gynaecologists and experts in evidence-based medicine from Europe, as well as an endometriosis self-help group representative. After reviewing existing evidence-based guidelines and systematic reviews, the expert panel met on three occasions for a day during which the guideline was developed and refined. Recommendations based solely on the clinical experience of the panel were avoided as much as possible. The entire ESHRE Special Interest Group for Endometriosis and Endometrium was given the opportunity to comment on the draft guideline, after which it was available for comment on the ESHRE website for 3 months. The working group then ratified the guideline by unanimous or near-unanimous voting; finally, it was approved by the ESHRE Executive Committee. The guideline will be updated regularly, and will be made available at http://www.endometriosis.org/guidelines.html with hyperlinks to the supporting evidence, and the relevant references and abstracts. For women presenting with symptoms suggestive of endometriosis, a definitive diagnosis of most forms of endometriosis requires visual inspection of the pelvis at laparoscopy as the 'gold standard' investigation. However, pain symptoms suggestive of the disease can be treated without a definitive diagnosis using a therapeutic trial of a hormonal drug to reduce menstrual flow. In women with laparoscopically confirmed disease, suppression of ovarian function for 6 months reduces endometriosis-associated pain; all hormonal drugs studied are equally effective although their side-effects and cost profiles differ. Ablation of endometriotic lesions reduces endometriosis-associated pain and the smallest effect is seen in patients with minimal disease; there is no evidence that also performing laparoscopic uterine nerve ablation (LUNA) is necessary. In minimal-mild endometriosis, suppression of ovarian function to improve fertility is not effective, but ablation of endometriotic lesions plus adhesiolysis is effective compared to diagnostic laparoscopy alone. There is insufficient evidence available to determine whether surgical excision of moderate-severe endometriosis enhances pregnancy rates. IVF is appropriate treatment especially if there are coexisting causes of infertility and/or other treatments have failed, but IVF pregnancy rates are lower in women with endometriosis than in those with tubal infertility. The management of severe/deeply infiltrating endometriosis is complex and referral to a centre with the necessary expertise is strongly recommended. Patient self-help groups can provide invaluable counselling, support and advice.

Ovarian Cancer Development and Metastasis

Abstract: The biology of ovarian carcinoma differs from that of hematogenously metastasizing tumors because ovarian cancer cells primarily disseminate within the peritoneal cavity and are only superficially invasive. However, since the rapidly proliferating tumors compress visceral organs and are only temporarily chemosensitive, ovarian carcinoma is a deadly disease, with a cure rate of only 30%. There are a number of genetic and epigenetic changes that lead to ovarian carcinoma cell transformation. Ovarian carcinoma could originate from any of three potential sites: the surfaces of the ovary, the fallopian tube, or the mesothelium-lined peritoneal cavity. Ovarian cacinoma tumorigenesis then either progresses along a stepwise mutation process from a slow growing borderline tumor to a well-differentiated carcinoma (type I) or involves a genetically unstable high-grade serous carcinoma that metastasizes rapidly (type II). During initial tumorigenesis, ovarian carcinoma cells undergo an epithelial-to-mesenchymal transition, which involves a change in cadherin and integrin expression and up-regulation of proteolytic pathways. Carried by the peritoneal fluid, cancer cell spheroids overcome anoikis and attach preferentially on the abdominal peritoneum or omentum, where the cancer cells revert to their epithelial phenotype. The initial steps of metastasis are regulated by a controlled interaction of adhesion receptors and proteases, and late metastasis is characterized by the oncogene-driven fast growth of tumor nodules on mesothelium covered surfaces, causing ascites, bowel obstruction, and tumor cachexia.