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Background: Outpatient monoclonal antibodies are no longer effective and antiviral treatments for coronavirus disease 2019 (COVID-19) disease remain largely unavailable in many countries worldwide. Although treatment with COVID-19 convalescent plasma (CCP) is promising, clinical trials among outpatients have shown mixed results., Methods: We conducted an individual participant data meta-analysis from outpatient trials to assess the overall risk reduction for all-cause hospitalizations by day 28 in transfused participants. Relevant trials were identified by searching Medline, Embase, medRxiv, World Health Organization COVID-19 Research Database, Cochrane Library, and Web of Science from January 2020 to September 2022., Results: Five included studies from 4 countries enrolled and transfused 2620 adult patients. Comorbidities were present in 1795 (69%). The virus neutralizing antibody dilutional titer levels ranged from 8 to 14 580 in diverse assays. One hundred sixty of 1315 (12.2%) control patients were hospitalized, versus 111 of 1305 (8.5%) CCP-treated patients, yielding a 3.7% (95% confidence interval [CI], 1.3%-6.0%; P = .001) absolute risk reduction and 30.1% relative risk reduction for all-cause hospitalization. The hospitalization reduction was greatest in those with both early transfusion and high titer with a 7.6% absolute risk reduction (95% CI, 4.0%-11.1%; P = .0001) accompanied by at 51.4% relative risk reduction. No significant reduction in hospitalization was seen with treatment >5 days after symptom onset or in those receiving CCP with antibody titers below the median titer., Conclusions: Among outpatients with COVID-19, treatment with CCP reduced the rate of all-cause hospitalization and may be most effective when given within 5 days of symptom onset and when antibody titer is higher., Competing Interests: Potential conflicts of interest. R. L. has received fees from Pfizer for serving as subinvestigator of a COVID vaccine trial. F. P. has received fees from Pfizer for serving as a principal investigator for a COVID vaccine trial. D. J. S. is a founder and board member of AliquantumRx with stock options; Hemex Health malaria diagnostics consulting; royalties for malaria diagnostic test control standards from Alere (Binax Inc/D/B/A Inverness Medical); consulting fees for legal malaria case from Mabrey Firm (2019); the following grants or contracts: NIH/NIAID R01AI150763, NIH R21TR001737, NIH R01AI111962, DOD TB210115 (CDMRP Tick-Borne Disease Research Program); the following patents: USP 9642865 (issued 9 May 2017, New angiogenesis inhibitors), USP 7270948 (issued 18 September 2007, Detection of malaria parasites by laser desorption mass spectrometry), Salts and polymorphs of cethromycin for the treatment of disease (pending, application 20210163522), and Macrolide compounds and their use in liver stage malaria and related disease (pending, application PCT/US2015/046665); and participation on 2018 NIAID Safety Monitoring Committee/Independent Safety Monitor Intramural, all outside the submitted work. B. J. A. R. reports advisory board membership for Roche and AstraZeneca on a COVID-19 therapy; membership on a data and safety monitoring board (DSMB) for Exevir; consulting fees from Roche and AstraZeneca; grants or contracts and payment or honoraria for lectures, presentations, speaker’s bureaus, manuscript writing, or educational events from Gilead Sciences; and support for attending meetings and/or travel from Pfizer. J. J. Z. reports consulting fees from City of Hope; cell therapy consultant; participation on DSMB for the PACER trial; DSMB for the Tolerant trial; and advisory boards for Sanofi and Sobi. L. J. D. reports the following grants or contracts: 75A50120C00094 (BARDA), Collection, testing, and provision of COVID-19 convalescent plasma for NHLBI/NIH (C3PO) through America's Blood Centers; US Veterans Health Administration, Pittsburgh (contract number 36C24E20D0027, VA CURES-1); and Vanderbilt University (Collection, testing, and provision of COVID-19 convalescent plasma for Association of Convalescent Plasma Treatment with Mortality and Clinical Trajectory in Patients Hospitalized with COVID-19 in the Community Setting). B. P. reports the following grants or contracts: COVID Trials, Incyte, Parexel, Novartis Pharmaceuticals, Partner Therapeutics, Fulcrum Therapeutics (to University Health Science Center), and Pulmonary Hypertension Trials, United Therapeutics, GlaxoSmithKline, Insmed, Merck Sharp & Dohme (to University of Texas Health Center). C. W. C. reports consulting honorarium for participation on NHLBI ACTIV4 CONNECTS Steering Committee. I. E. reports support for attending meetings and/or travel for 50 Congreso Argentino de Medicina Respiratoria 2022, Abstract Scholarship, American Thoracic Society, International Conference in Philadelphia, 2020 Assembly on Pediatrics. G. P. M. reports grants or contracts from Pfizer, Moderna, Medicago, and Merck for clinical research (as principal investigator), and payment for presentations from Moderna. D. O. reports consulting fees paid to author from the Fight Infectious Diseases Foundation and the Infectious Diseases Department, Hospital Universitari Germans Trias i Pujol. B. R. M. reports the following grants or contracts: NIH/NIAID R01AI150763, NIH R21TR001737, NIH R01AI111962, and DOD TB210115 (CDMRP Tick-Borne Disease Research Program). D. W. reports payment or honoraria for lectures, presentations, speaker’s bureaus, manuscript writing, or educational events from AstraZeneca, and support for attending meetings and/or travel from Laboratorios Raffo. C. R. reports grants or contracts from Gilead Sciences, ViiV Healthcare, Janssen-Cilag, AIDSfonds, and Health∼Holland; participation on a DSMB or advisory board as well as support for attending meetings and/or travel from Gilead Sciences and ViiV Healthcare; and gifts for the #awarehivukraine foundation. M. A. H. reports grants or contracts from Gilead, Insmed, and AN2 Therapeutics, as well as participation on the AIDS Clinical Trials Group Tuberculosis Transformative Science Group Study Monitoring Committee. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: The efficacy of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) convalescent plasma (CCP) for preventing infection in exposed, uninfected individuals is unknown. CCP might prevent infection when administered before symptoms or laboratory evidence of infection., Methods: This double-blinded, phase 2 randomized, controlled trial (RCT) compared the efficacy and safety of prophylactic high titer (≥1:320 by Euroimmun ELISA) CCP with standard plasma. Asymptomatic participants aged ≥18 years with close contact exposure to a person with confirmed coronavirus disease 2019 (COVID-19) in the previous 120 hours and negative SARS-CoV-2 test within 24 hours before transfusion were eligible. The primary outcome was new SARS-CoV-2 infection., Results: In total, 180 participants were enrolled; 87 were assigned to CCP and 93 to control plasma, and 170 transfused at 19 sites across the United States from June 2020 to March 2021. Two were excluded for screening SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR) positivity. Of the remaining 168 participants, 12/81 (14.8%) CCP and 13/87 (14.9%) control recipients developed SARS-CoV-2 infection; 6 (7.4%) CCP and 7 (8%) control recipients developed COVID-19 (infection with symptoms). There were no COVID-19-related hospitalizations in CCP and 2 in control recipients. Efficacy by restricted mean infection free time (RMIFT) by 28 days for all SARS-CoV-2 infections (25.3 vs 25.2 days; P = .49) and COVID-19 (26.3 vs 25.9 days; P = .35) was similar for both groups., Conclusions: Administration of high-titer CCP as post-exposure prophylaxis, although appearing safe, did not prevent SARS-CoV-2 infection., Clinical Trials Registration: NCT04323800., Competing Interests: Potential conflicts of interests . The authors report the following: K. G.reports grants or contracts unrelated to this work and paid to institution from NIHI, personal fees from Aspen Institute, Teach for America and UpToDate. T. G. reports paid consultant for Fresenius Kabi USA and reports <$5000 of JNJ stock. A. C. reports Scientific Advisory Board of Sabtherapeutics (cow-derived human immunoglobulins COVID-19 treatment and other infectious diseases) and Ortho Diagnostics Speakers Bureau, and consulting fees from Ortho Diagnostics and Pfizer, and payment for expert testimony from King & Spalding LLP, and leadership or fiduciary role with American Society for Microbiology, and part owner of Melatech. E. B.’s time is funded in part by National Heart Lung and Blood Institute (NHLBI) through grant number 1K23HL151826, is a member of the FDA Blood Products Advisory Committee, Abbot Laboratories, Grifols Diagnostic Solutions, personal fee for invited educational presentations for Terumo BCT (honoraria for educational webinar), and advisor for California Institute for Regenerative Medicine (convalescent plasma program), and unpaid participation as invited member for a Data Safety Monitoring Board for the following trial: ‘Assessment of safety and efficacy of COVID-19 Convalescent Plasma for treatment of COVID-19 in adults in Uganda; A Phase III randomized controlled trial. S. S. reports research grants from Ansun, Astellas, Cidara, Emergent Biosolutions, F2G, Gilead, Merck, Scynexis, Zeteo, Shionogi and Shire, personal fees from Adagio, Adamis, Celltrion, Immunome, Intermountain Health and Karyopharm (consultant, advisory board and data safety monitoring board member), participation on a Data Safety Monitoring Board or Advisory Board for Adagio, Adamis, Amplyx, Immunome, Intermountain Health, Janssen, Karyopharm, Reviral, and stock options from Immunome. D. Su. reports grants or contracts unrelated to this work from NIH/NIAID (R01AI150763 Dual artemisinin action combats resistance; NIH R21TR001737 Quantum model repurposing of cethromycin for liver stage malaria; NIH R01AI111962 Optimized Combination Antimalarial Drug Therapy), founder, board member, and stock options from AliquantumRx, DSMB member NIAID SMC/ISM Intramural 2018, medical royalties for malaria test (Binax Inc/D/B/A Inverness), consultant on malaria diagnosis for Masimo and Hemex Health and consulting fees for legal malaria case (Mabrey Firm 2019 and Ressler and Ressler 2018), and patents (Issued-USP 9,642,865 9 May 2017 New angiogenesis inhibitors; Issued-USP 9,568,471 14 February 2017 Malaria Diagnosis in Urine; Issued-USP 7,270,948 18 September 2007 Detection of malaria parasites by laser desorption mass spectrometry; Pending SALTS AND POLYMORPHS OF CETHROMYCIN FOR THE TREATMENT OF DISEASE Patent Application (Application number 20210163522); and Pending- Macrolide compounds and their use in liver stage malaria and related disease (Application number PCT/US2015/046665). E. C. reports research grants from Gilead Sciences and Merck Sharp and Dohme (funds paid to UC Regents), payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Gilead Sciences, and advisory board member for Gilead Sciences. J. C. is aconsultant for Merck and Co. and Resverlogix. S. Ka. reports educational product development for Integritas Communications Group. G. M. reports research grants from Teva, Sanofi Regeneron, Astra Zeneca, Alk Abello, Genentech, Propeller Health, GlaxoSmithKline, and Novartis, and honoraria paid to author for HCPLive educational presentation, and position as Secretary/Treasurer (March 2019 to February 2020), President-Elect (March 2020 to February 2021), President (March 2021 to February 2022) of the American Academy of Allergy, Asthma, and Immunology (payments made to institution during term as President), and Director of American Board of Allergy and Immunology (2020–2025), Co-Chair of American Board of Allergy and Immunology Continuous Assessment Program Examination Committee (2020–2022) (honoraria paid to author). C. S. reports research grants from Centers for Disease Control and Prevention, Merck and Pfizer. D. J. reports grants or contracts unrelated to this work from National Eye Institute, National Institutes of Health, and National Center for Advancing Translational Research, National Institutes of Health; Board of Directors of the American Uveitis Society, speaking honoraria from Retina Society, Controversies in Ophthalmology, University of Rochester, Wills Eye Hospital, LSU School of Medicine and Icahn School of Medicine at Mt. Sinai, and participation on a Data Safety Monitoring Board or Advisory Board for National Eye Institute Intramural Branch. D. Sh. reports numerous grants supporting ongoing and completed research unrelated to this article from the NIH; and is a member of DSMB for the Pelvic Floor Disorders Network (stipend support for meeting activities 4/year). D. H. reports consulting fees from Neurotrope. M. H. reports grants or contracts unrelated to this work from NIH National Center of Advancing Translational Sciences (NCATS) (grant number KL2TR001426), NIH National Institute of Allergy and Infectious Diseases (NIAID) (grant number UM1AI069501), and Insmed Inc, and is a member of the AIDS Clinical Trials Group (ACTG) Tuberculosis Transformative Science Group (TB TSG) Study Monitoring Committee. O. L. reports grants or contracts unrelated to this work from Division of Intramural Research, NIAID, NIH. V. C. reports stock/stock options from spouse’s employer and under spouse’s name from Pfizer. D. T. reports board membership with Excision Bio and board membership (DSMB) with Merck and Co (paid to author); employment with JHU; various expert testimony paid to author; honoraria for CME programs only, paid to author (no service on corporate speaker’s bureau); royalties from UpToDate; and stock/stock options with Excision Bio. N. M. reports participation as HyazOUT and UtahONE combined DSMB member for NIH National Center for Advancing Translational Sciences (NCATS) U24TR001609-S3.All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: It is unknown if probiotics exert pathogen-specific effects in children with diarrhea secondary to acute gastroenteritis., Methods: Analysis of patient-level data from 2 multicenter randomized, placebo controlled trials conducted in pediatric emergency departments in Canada and the United States. Participants were 3-48 months with >3 diarrheal episodes in the preceding 24 hours and were symptomatic for <72 hours and <7 days in the Canadian and US studies, respectively. Participants received either placebo or a probiotic preparation (Canada-Lactobacillus rhamnosus R0011/Lactobacillus helveticus R0052; US-L. rhamnosus GG). The primary outcome was post-intervention moderate-to-severe disease (ie, ≥9 on the Modified Vesikari Scale [MVS] score)., Results: Pathogens were identified in specimens from 59.3% of children (928/1565). No pathogen groups were less likely to experience an MVS score ≥9 based on treatment allocation (test for interaction = 0.35). No differences between groups were identified for adenovirus (adjusted relative risk [aRR]: 1.42; 95% confidence interval [CI]: .62, 3.23), norovirus (aRR: 0.98; 95% CI: .56, 1.74), rotavirus (aRR: 0.86; 95% CI: .43, 1.71) or bacteria (aRR: 1.19; 95% CI: .41, 3.43). At pathogen-group and among individual pathogens there were no differences in diarrhea duration or the total number of diarrheal stools between treatment groups, regardless of intervention allocation or among probiotic sub-groups. Among adenovirus-infected children, those administered the L. rhamnosus R0011/L. helveticus R0052 product experienced fewer diarrheal episodes (aRR: 0.65; 95% CI: .47, .90)., Conclusions: Neither probiotic product resulted in less severe disease compared to placebo across a range of the most common etiologic pathogens. The preponderance of evidence does not support the notion that there are pathogen specific benefits associated with probiotic use in children with acute gastroenteritis., Clinical Trials Registration: NCT01773967 and NCT01853124., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: Intravenous fluid (IVF) is a frequently recommended intervention in Ebola virus disease (EVD), yet its impact on patient outcomes remains unclear., Methods: This retrospective cohort study evaluated patients with EVD admitted to 5 Ebola treatment units (ETUs) in West Africa. The primary outcome was the difference in 28-day survival between cases treated and not treated with IVF. To control for demographic and clinical factors related to both IVF exposure and survival, cases were compared using propensity score matching. To control for time-varying patient and treatment factors over the course of ETU care, a marginal structural proportional hazards model (MSPHM) with inverse probability weighting was used to assess for 28-day survival differences., Results: Among 424 EVD-positive cases with data for analysis, 354 (83.5%) were treated with IVF at some point during their ETU admission. Overall, 146 (41.3%) cases treated with IVF survived, whereas 31 (44.9%) cases not treated with any IVF survived (P = .583). Matched propensity score analysis found no significant difference in 28-day survival between cases treated and not treated with IVF during their first 24 and 48 hours of care. Adjusted MSPHM survival analyses also found no significant difference in 28-day survival for cases treated with IVF (27.3%) compared to those not treated with IVF (26.9%) during their entire ETU admission (P = .893)., Conclusions: After adjustment for patient- and treatment-specific time-varying factors, there was no significant difference in survival among patients with EVD treated with IVF as compared to those not treated with IVF., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: Reliable data are lacking on pregnancy outcomes during Ebola virus disease (EVD) epidemics. We aimed to characterize symptoms and outcomes among pregnant women admitted to Ebola treatment units (ETUs) with suspected and confirmed EVD to better inform obstetric management., Methods: We analyzed a retrospective cohort of reproductive-aged women presenting to 5 West African ETUs from September 2014 to September 2015. We compared clinical symptoms, risk of EVD diagnosis, and mortality between pregnant and nonpregnant women., Results: Of 729 reproductive-aged women admitted to study ETUs, 44 (6%) reported pregnancy. Thirteen of 44 pregnant women (30%) tested EVD positive; 6 of 13 (46%) died. Pregnant women were less likely than nonpregnant women to report anorexia, asthenia, diarrhea, fever, myalgias/arthralgias, nausea, or vomiting (P < .05) at admission. Pregnant women with suspected EVD had the same risk, however, of laboratory-confirmed EVD (30% vs 24%, P = .38). While pregnant women with confirmed EVD had similar Ebola viral loads on presentation to nonpregnant women, as measured by initial cycle threshold (26.4 vs 23.2, P = .16), they were less likely to have myalgias/arthralgias (P< .001) and vomiting (P = .02). Both all-cause mortality (14% vs 19%, P = .39) and EVD-specific mortality (46% vs 54%, P = .60) were not significantly different between pregnant and nonpregnant women. Two neonates born live in the ETU died within 8 days., Conclusions: We find no evidence to support a difference in the risk of death between pregnant women with suspected or confirmed EVD compared to nonpregnant women. Limited data suggest poor fetal and neonatal outcomes in EVD-affected pregnancies., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: The clinical and virologic characteristics of Ebola virus disease (EVD) in children have not been thoroughly documented., Methods: Consecutive children aged <18 years with real-time polymerase chain reaction (RT-PCR)-confirmed EVD were enrolled retrospectively in 5 Ebola treatment units in Liberia and Sierra Leone in 2014/2015. Data collection and medical management were based on standardized International Medical Corps protocols. We performed descriptive statistics, multivariate logistic regression, and Kaplan-Meier survival analyses., Results: Of 122 children enrolled, the median age was 7 years and one-third were aged <5 years. The female-to-male ratio was 1.3. The most common clinical features at triage and during hospitalization were fever, weakness, anorexia, and diarrhea, although 21% of patients were initially afebrile and 6 patients remained afebrile. Bleeding was rare at presentation (5%) and manifested subsequently in fewer than 50%. The overall case fatality rate was 57%. Factors associated with death in bivariate analyses were age <5 years, bleeding at any time during hospitalization, and high viral load. After adjustment with logistic regression modeling, the odds of death were 14.8-fold higher if patients were aged <5 years, 5-fold higher if the patient had any evidence of bleeding, and 5.2-fold higher if EVD RT-PCR cycle threshold value was ≤20. Plasmodium parasitemia had no impact on EVD outcomes., Conclusions: Age <5 years, bleeding, and high viral loads were poor prognostic indicators of children with EVD. Research to understand mechanisms of these risk factors and the impact of dehydration and electrolyte imbalance will improve health outcomes., (© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.)

Prostate cancer (PCa) is unique in its tendency to produce osteoblastic (OB) bone metastases. There are no existing therapies that specifically target the OB phase that affects 90% of men with bone metastatic disease. Prostatic acid phosphatase (PAP) is secreted by PCa cells in OB metastases and increases OB growth, differentiation, and bone mineralization. The purpose of this study was to investigate whether PAP effects on OB bone metastases are mediated by autocrine and/or paracrine alterations in the receptor activator of nuclear factor κ-B (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system. To investigate whether PAP modulated these factors and altered the bone reaction, we knocked down PAP expression in VCaP cells and stably overexpressed PAP in PC3M cells, both derived from human PCa bone metastases. We show that knockdown of PAP in VCaP cells decreased OPG while increasing RANK/RANKL expression. Forced overexpression of PAP in PC3M cells had the inverse effect, increasing OPG while decreasing RANK/RANKL expression. Coculture of PCa cells with MC3T3 preosteoblasts also revealed a role for secretory PAP in OB-PCa cross talk. Reduced PAP expression in VCaP cells decreased MC3T3 proliferation and differentiation and reduced their OPG expression. PAP overexpression in PC3M cells altered the bone phenotype creating OB rather than osteolytic lesions in vivo using an intratibial model. These findings demonstrate that PAP secreted by PCa cells in OB bone metastases increases OPG and plays a critical role in the vicious cross talk between cancer and bone cells. These data suggest that inhibition of secretory PAP may be an effective strategy for PCa OB bone lesions.

Context: Hormonal therapy has been the mainstay of treatment for advanced prostate cancer for over 70 yr. The timing and extent of androgen ablative therapy for earlier stage disease remains controversial. In addition, recent studies demonstrate that so-called "castration-resistant" tumors are still dependent on androgen receptor signaling., Patient and Methods: A 66-yr-old man presented with clinical stage T1C N+ M0 prostate cancer and received primary androgen deprivation therapy. Over the course of the next 17 yr, he was treated with various forms of androgen deprivation therapy, including two newer agents, abiraterone acetate and MDV 3100. A review of the literature was conducted to identify indications, controversies, and new developments regarding hormonal therapy for prostate cancer., Conclusions: Androgen deprivation therapy remains the treatment of choice for metastatic prostate cancer; however, it is not without its adverse effects, and most men with advanced disease eventually develop castration resistance. Newer compounds that more specifically and effectively target androgen and androgen receptor signaling in prostate cancer cells may provide more long-lasting remissions in advanced disease.

Study Objectives: The Institute of Medicine (IOM) has called for the elimination of resident work shifts exceeding 16 hours without sleep. We sought to comprehensively evaluate the effects of eliminating or reducing shifts over 16 hours., Design and Outcome Measures: We performed a systematic review of published and unpublished studies (1950-2008) to synthesize data on all intervention studies that have reduced or eliminated U.S. residents' extended shifts. A total of 2,984 citations were identified initially, which were independently reviewed by two authors to determine their eligibility for inclusion. All outcomes relevant to quality of life, education, and safety were collected. Study quality was rated using the U.S. Preventive Services Task Force methodology., Measurements and Results: Twenty-three studies met inclusion criteria (kappa = 0.88 [95% CI, 0.77-0.94] for inclusion decisions). Following reduction or elimination of extended shifts, 8 of 8 studies measuring resident quality of life found improvements. Four of 14 studies that assessed educational outcomes found improvements, 9 found no significant changes, and one found education worsened. Seven of 11 identified statistically significant improvements in patient safety or quality of care; no studies found that safety or care quality worsened., Conclusions: In a systematic review, we found that reduction or elimination of resident work shifts exceeding 16 hours did not adversely affect resident education, and was associated with improvements in patient safety and resident quality of life in most studies. Further multi-center studies are needed to substantiate these findings, and definitively measure the effects of eliminating extended shifts on patient outcomes.

The osteoprotegerin (OPG)/receptor activator of nuclear factor-kappaB ligand (RANKL)/receptor activator of nuclear factor-kappaB (RANK) system is the dominant and final mediator of osteoclastogenesis. Abnormalities of this system have been implicated in the pathogenesis of many skeletal diseases. Cyclooxygenase (COX)-2 and prostaglandin (PG)E(2), a major eicosanoid product of the COX-2-catalyzed pathway, play key roles in normal bone tissue remodeling. PGE(2) exerts its actions by binding and activating the E series of prostaglandin (EP) receptor. Activation of EP(2) and EP(4) receptors is associated with PGE(2)-induced osteoclast differentiation. IL-6, a major proinflammatory cytokine, has also been reported to induce osteoclast differentiation. Although interactions between the COX-2/PGE(2) and IL-6 systems have been described in bone cells, the mechanisms underlying these cooperative signaling pathways and the possible involvement of the OPG/RANKL/RANK system have not been fully elucidated. We demonstrate that COX-2, PGE(2), and IL-6 stimulate osteoblast growth and osteoclast differentiation. Effects on osteoclast differentiation, particularly with IL-6, were most marked when osteoclast precursor cells were grown in coculture with osteoblasts, indicating a possible role of the RANK/RANKL/OPG system. COX-2 and PGE(2) stimulated osteoclastogenesis through inhibition of OPG secretion, stimulation of RANKL production by osteoblasts, and up-regulation of RANK expression in osteoclasts. PGE(2) stimulated IL-6 secretion by bone cells, whereas COX-2 inhibitors decreased this same parameter. IL-6, in turn, increased PGE(2) secretion, COX-2, and EP receptor subtype expression in bone cells. Finally, IL-6 was the mediator of PGE(2)-induced suppression of OPG production by osteoblasts. These findings provide evidence for cross-talk between the PGE(2) and IL-6 signaling enhance osteoclast differentiation via effects on the OPG/RANKL/RANK system in bone cells.

The first rate-limiting step in the conversion of arachidonic acid to PGs is catalyzed by cyclooxygenase (Cox). Two isoforms of Cox have been identified, Cox-1 (constitutively expressed) and Cox-2 (inducible form), which are the products of two different genes. In this study we describe the immunohistochemical localization of Cox-1 and -2 in the human male fetal and adult reproductive tracts. There was no Cox-1 expression in fetal samples (prostate, seminal vesicles, or ejaculatory ducts), and only minimal expression in adult tissues. There was no expression of Cox-2 in the fetal prostate. In a prepubertal prostate there was some Cox-2 expression that localized exclusively to the smooth muscle cells of the transition zone. In adult hyperplastic prostates, Cox-2 was strongly expressed in smooth muscle cells, with no expression in the luminal epithelial cells. Cox-2 was strongly expressed in epithelial cells of both fetal and adult seminal vesicles and ejaculatory ducts. The Cox-2 staining intensity in the fetal ejaculatory ducts during various times of gestation correlated with previously reported testosterone production rates by the fetal testis. These data indicate that Cox-2 is the predominant isoform expressed in the fetal male reproductive tract, and its expression may be regulated by androgens. The distinct cell type-specific expression patterns of Cox-2 in the prostate (smooth muscle) vs. the seminal vesicles and ejaculatory ducts (epithelium) may reflect the different roles of PGs in these tissues.

Androgens are known to directly stimulate prostate cancer cell growth. We have previously reported that LNCaP prostate cancer cells were dependent upon stromal coinoculation for growth in nude mice and that the stromal cells secreted a potent angiogenic factor, vascular endothelial growth factor (VEGF), which stimulated tumor angiogenesis. Immunohistochemical staining localized VEGF expression primarily to the stromal cells of human fetal and adult hyperplastic prostates, with both stromal and epithelial cell VEGF expression in prostate cancer. In the present studies, we test the hypothesis that androgens, in addition to their direct effects on prostate epithelial cells, have indirect effects on these cells via up-regulation of stromal VEGF production and angiogenesis. Primary cultures of human prostate fetal fibroblasts were treated with dihydrotestosterone (DHT), and the effects on VEGF messenger RNA (mRNA) expression were determined by Northern blotting. DHT (10 nM) increased VEGF mRNA levels maximally after 2 h. Nuclear run-on transcription assays demonstrated a 2-fold increase in the VEGF transcription rate 2 h after the addition of DHT. VEGF mRNA stability was unaffected by DHT addition. VEGF protein levels were determined by enzyme-linked immunosorbent assay and were increased 2-fold 4 h after DHT addition. These data indicate that androgens increase VEGF transcription and secretion of biologically active VEGF from human prostatic stroma. Androgens, therefore, may indirectly enhance prostate growth via up-regulation of VEGF from the surrounding stroma.

The activity of the type 2 isozyme of steroid 5 alpha-reductase is crucial for normal development of the external genitalia and prostate in human males. We used immunohistochemistry to localize type 2 isozyme expression in the human male fetal reproductive tract and adult prostate. In fetal tissue, the stroma of the seminal vesicles, corpus cavernosum, corpus spongiosum, dorsal vein complex, scrotal skin, and prostate expressed the enzyme. In addition, the epithelial cells of the fetal urethra and proximal prostatic ducts stained positively. The type 2 isozyme could not be detected in epithelial cells of the fetal prostatic acini, seminal vesicles, prostatic utricle, ejaculatory ducts, epididymides, and Cowper's glands. Adult prostate specimens were derived from transurethral prostatectomies performed for benign prostatic hyperplasia. Enzyme expression in these benign prostatic hyperplasia samples localized to the stroma and epithelial cells of the urethra and proximal ducts. No staining was detected in the acinar (luminal and basal) epithelial cells. Double staining with an antismooth muscle actin antibody localized type 2 isozyme expression to the stromal fibroblast cells of the prostate. Double staining with an androgen receptor antibody localized AR expression to the acinar epithelial cells and stromal fibroblasts. These data indicate that 5 alpha-reductase type 2 is expressed throughout the developing male genitourinary tract and functions as both an autocrine and a paracrine mediator of growth and differentiation.

Stromal enlargement plays a key role in the development of benign prostatic hypertrophy in humans. Human prostatic fibroblasts were obtained from fetal and adult prostates and characterized as to their androgen and estrogen receptor status and growth in response to dihydrotestosterone (DHT), estradiol (E2), hydroxyflutamide (OH-FLU), hydrocortisone, basic fibroblast growth factor (bFGF), and epidermal growth factor (EGF). In addition, the ability of hormones and growth factors to induce the messenger RNA (mRNA) for the c-fos protooncogene was assessed as a measure of the early, direct effects of these compounds on cellular proliferation. Nuclear androgen receptors were demonstrable by immunocytochemistry in both fetal and adult cells. Nuclear estrogen receptor staining was negative. Neither E2 nor hydrocortisone increased cellular proliferation. Both EGF and bFGF did increase cellular growth. DHT (10(-8)-10(-7) M) had a significant stimulatory effect on cell growth only in serum-free media. OH-FLU addition enhanced DHT induced proliferation. Changing the media during the course of the experiment obliterated the stimulatory effect of DHT. Both EGF (10 ng/ml) and bFGF (20 ng/ml) increased the mRNA for the c-fos protooncogene. DHT (10(-7) M) did not induce the mRNA for c-fos. We conclude that EGF, bFGF, and DHT (especially in combination with OH-FLU) increase the proliferation of human prostatic fetal and adult fibroblasts in vitro. E2 has no effect on fibroblast proliferation. The stimulatory effects of EGF and bFGF are direct, whereas the effect of DHT appears to be indirect, possibly mediated via the increased production and/or secretion of growth factors.

To determine the effects of reversible medical castration on prostatic size and symptoms we treated 15 patients with benign prostatic hypertrophy with a long-acting GnRH analog, leuprolide (1 mg/day sc), for a minimum of 4 months. The men's serum testosterone, dihydrotestosterone, and estradiol concentrations fell to very low levels within 4-6 weeks after the initiation of treatment. Transrectal ultrasonography of the prostate demonstrated an average shrinkage of 40% after 4 months of treatment (n = 15) and 46% after 6 months of treatment (n = 11). All 15 men had improvement in urinary flow and, to a lesser extent, in nocturia and frequency. The side-effects of the therapy were decreased potency and flushing. The most dramatic improvement occurred in 4 of the 5 men who had complete urinary obstruction before treatment. One man had a suprapubic cystotomy tube removed during the fifth treatment month. Two other men who had Foley catheters before treatment are voiding well without catheters since their third treatment month. Another man who had a very large prostate (300 g) before treatment had one successful voiding trial, although he still has a suprapubic cystotomy tube. One man decided to stop treatment after 6 months. Two months later his hormone values and prostate size had returned to pretreatment levels. One man treated during the fourth and fifth months with fluoxymesterone in addition to leuprolide had regrowth of his prostate while receiving this androgen. We conclude that leuprolide treatment of men with benign prostatic hypertrophy results in shrinkage of prostatic size and concomitant improvement in the obstructive symptoms of prostatism. The prostatic shrinkage reverses when treatment is discontinued or combined with androgen.

To determine the effects of reversible medical castration on prostatic size in patients with benign prostatic hypertrophy (BPH), 3 patients with BPH were treated with a GnRH analogue, leuprolide, for six months at a dosage of .2ml (1 mg) s.c. daily. Serum testosterone, dihydrotestosterone and estradiol fell to castration levels 4-6 weeks after the initiation of treatment and remained low throughout the study period. Transrectal ultrasonography of the prostate demonstrated an average decrease in prostatic volume of 58% at 6 months, with the greatest rate of decrease occurring during the 2nd to 5th months of treatment. One man who had acute urinary retention before treatment was subsequently able to void extremely well. In a second man the symptoms of prostatism diminished but in the third urinary frequency and nocturia persisted in spite of a reduction in prostatic size, presumably because his symptoms were due to renal insufficiency.