I. Visions of epithelial research

2003 ◽  
Vol 284 (4) ◽  
pp. G547-G550 ◽  
Author(s):  
Marshall H. Montrose

Epithelial cells are gatekeepers that sit at the interface between two compartments. By controlling the flow of molecules and information between two compartments, epithelial cells provide unique benefit to the body. This article provides a brief appraisal of our current knowledge about the functions of gastrointestinal epithelial cells as a functionally diverse set of cells mediating transepithelial transport and as a continually renewing layer of cells. The convergence of new methodologies in laser capture microdissection, microarray analyses, microscopic analyses, and generation of mutant animals provides an exciting template for future research.

2017 ◽  
Vol 10 (3) ◽  
pp. 342-359 ◽  
Author(s):  
Mokter Hossain

Purpose The purpose of this paper is to provide state-of-the-art knowledge about business model innovation (BMI) and suggest avenues for future research. Design/methodology/approach A systematic literature review approach was adopted with thematic analysis being conducted on 92 articles. Findings The body of knowledge for this concept is in its infancy and is highly fragmented. This study therefore attempts to consolidate this fragmented knowledge. It reveals dominant themes, establishes coherence, and identifies conflicting arguments in the current literature. It also points out gaps in the research and highlights new directions for research. Research limitations/implications This study analyzed articles that were found based on a systematic literature review approach. Practical implications This study identifies some fundamental issues that managers need to understand regarding BMI. Originality/value The main value of this study lies in its synthesis of the current knowledge of BMI.


Author(s):  
Marc Sim ◽  
Brian Dawson ◽  
Grant Landers ◽  
Debbie Trinder ◽  
Peter Peeling

The trace element iron plays a number of crucial physiological roles within the body. Despite its importance, iron deficiency remains a common problem among athletes. As an individual’s iron stores become depleted, it can affect their well-being and athletic capacity. Recently, altered iron metabolism in athletes has been attributed to postexercise increases in the iron regulatory hormone hepcidin, which has been reported to be upregulated by exercise-induced increases in the inflammatory cytokine interleukin-6. As such, when hepcidin levels are elevated, iron absorption and recycling may be compromised. To date, however, most studies have explored the acute postexercise hepcidin response, with limited research seeking to minimize/attenuate these increases. This review summarizes the current knowledge regarding the postexercise hepcidin response under a variety of exercise scenarios and highlights potential areas for future research—such as: a) the use of hormones though the female oral contraceptive pill to manipulate the postexercise hepcidin response, b) comparing the use of different exercise modes (e.g., cycling vs. running) on hepcidin regulation.


2003 ◽  
Vol 284 (1) ◽  
pp. C220-C232 ◽  
Author(s):  
Corinne Isnard-Bagnis ◽  
Nicolas Da Silva ◽  
Valérie Beaulieu ◽  
Alan S. L. Yu ◽  
Dennis Brown ◽  
...  

Epithelial cells of the epididymis and vas deferens establish an optimum luminal environment in which spermatozoa mature and are stored. This is achieved by active transepithelial transport of various ions including Cl−and H+. We investigated the localization of three closely related members of the ClC family, ClC-3, ClC-4, and ClC-5, in the epididymis and vas deferens. RT-PCR using mRNA isolated by laser capture microdissection (LCM)-detected ClC-3 and ClC-5 transcripts but did not detect any ClC-4-specific transcript. Western blot and immunofluorescence analysis demonstrated that ClC-3 and ClC-5 proteins are present in all regions of the epididymis and in the vas deferens. ClC-5 is expressed exclusively in H+-ATPase-rich cells (narrow and clear cells). Confocal microscopy showed that ClC-5 partially colocalizes with the H+-ATPase in the subapical pole of clear cells. ClC-3 is strongly expressed in the apical membrane of principal cells of the caput epididymidis and the vas deferens and is less abundant in principal cells of the body and cauda epididymidis. These findings are consistent with a potential role for ClC-3 in transepithelial chloride transport by principal cells and for ClC-5 in the acidification of H+-ATPase-containing vesicles in narrow and clear cells. ClC-5 might facilitate endosome trafficking in the epididymis, as has been proposed in the kidney.


2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e22036-e22036
Author(s):  
C. P. Miller ◽  
K. Loeb ◽  
K. Edlefsen ◽  
N. Urban ◽  
C. A. Blau

e22036 Background: Adverse effects of erythropoiesis stimulating agents on tumor progression and/or survival were observed in recent Phase III clinical trials, however, mechanisms are not understood. Whether tumor erythropoietin receptor (EpoR) expression is associated with erythropoietin-dependent tumor progression remains unclear, owing in part to the lack of specificity of commercial antibodies for protein detection. To overcome issues of protein detection, we previously optimized a quantitative RTPCR approach for reliable measurements of low level EpoR mRNA in primary tumor samples, and observed a 30-fold range of EpoR expression among panels of both breast and head and neck cancer samples. Methods: To test whether EpoR mRNA is expressed in tumor epithelial cells, we performed laser capture microdissection to fractionate 3 breast tumors into tumor epithelial enriched vs. depleted fractions. In each fraction, lineage marker and EpoR mRNA expression was normalized to 3 endogenous control genes. Results: Vascular endothelial markers in tumor epithelial-enriched fractions were reduced by an average of 15.3-fold (vascular endothelial cadherin) and 18.5-fold (platelet cell adhesion molecule 1) while the stromal marker vimentin was reduced by 14.7-fold. EpoR expression was enriched by 4.9-, 7.2-, and 1.1-fold in epithelial enriched fractions. Conclusions: Despite the depletion of endothelial cells, EpoR mRNA was at the same level or enriched in tumor epithelial fractions. These results demonstrate that malignant epithelial cells are a major source of EpoR mRNA in primary tumors. Applying this approach to additional breast cancer specimens as well as other cancer types will improve our understanding of erythropoietin-associated tumor progression. [Table: see text]


2000 ◽  
Vol 191 (4) ◽  
pp. S93
Author(s):  
Brian C.-S Liu ◽  
Max Ahn ◽  
Lisa J Weinstein ◽  
Michael H Weinstein ◽  
Ian LaRose ◽  
...  

2021 ◽  
Vol 9 ◽  
Author(s):  
Lingzhi Li ◽  
Shuni Liao ◽  
Jingfeng Yuan ◽  
Endong Wang ◽  
Jianjun She

In contemporary “high-risk” society, unexpected disasters (epidemics and extreme weather) and chronic pressures (aging problems) put tremendous pressure on healthcare facilities. Enhancing the healthcare facilities' resilience ability to resist, absorb, and respond to disaster disruptions is urgent. This study presents a scientometric review for healthcare facility resilience research. A total of 374 relevant articles published between 2000 and 2020, collected from Web of Science (WoS) core collection database, Scopus database and MEDLINE database were reviewed and analyzed. The results indicated that research on resilience in healthcare facilities went through three development periods, and the research involved countries or institutions that are relatively scattered. The studies have been focused on the subject categories of engineering, public, environmental, and occupational health. The keywords of “resilience,” “hospital,” “disaster,” “healthcare,” and “healthcare facility” had the most frequency. Furthermore, based on the literature co-citation networks and content analysis, the detected seven co-citation clusters were grouped into four knowledge domains: climate change impact, strengthening resilience in response to war and epidemic, resilience assessment of healthcare facility, and the applications of information system. Moreover, the timeline view of literature reflected the evolution of each domain. Finally, a knowledge map for resilience of healthcare facilities was put forward, in which critical research contents, current knowledge gaps, and future research work were discussed. This contribution will promote researchers and practitioners to detect the hot topics, fill the knowledge gaps, and extend the body of research on resilience of healthcare facilities.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
W Palomino ◽  
M P Rivas ◽  
F Argandoña ◽  
L Devoto ◽  
A Fuenets ◽  
...  

Abstract Study question Is progesterone receptor (PGR) downregulation disrupted within endometrial epithelial compartment, during embryo receptivity phase in assisted reproductive technology (ART) cycles? Summary answer PGR is not downregulated in endometrial epithelial cells from ART cycles during embryo receptivity phase. What is known already Progesterone (P4) promotes the downregulation of its own progesterone receptor (PGR). During the mid-luteal phase, PGR is downregulated in endometrial epithelial cells (EEC), a critical process for embryo implantation. Embryos are unable to attach to the maternal surface when PGR expression is sustained in EEC. Non-physiologic ovarian steroid produced or employed in ART cycles may alter endometrial development compromising its receptivity. Scarce information is available whether PGR is downregulated in EEC from ARTs including ovarian stimulation for in vitro fertilization (IVF) cycles or hormonal endometrial preparation for frozen thawed embryo transfer (HEP-FET). Study design, size, duration Cross sectional study including endometrial samples from fertile women during natural cycle (FNC, n = 23), from infertile women submitted to IVF (n = 19) and from infertile women who underwent mock HEP-FET (n = 35). Samples were obtained between 2018–2019. Sample size was calculated considering a power of 90%, alpha error=0.05, an expected PGR expression of 2 and 0.5 in ART and FNC groups, respectively, having a standard deviation=0.9. At least 9 patients would be necessary in each group. Participants/materials, setting, methods Endometrial samples were obtained during mid-luteal phase scheduled 7 days after ovulation in FNC, 5 days after oocyte retrieval in IVF without embryo transfer or 5 days after P4 supplementation in HEP-FET. Immunohistochemistry was employed to quantify PGR using histologic score (Hscore). PGR mRNA levels were determined by qRT-PCR from EEC dissected by laser capture microdissection. Anova test was used for comparing means of Hscore and mRNA among groups. Statistical significance was established as P < 0.05. Main results and the role of chance No statistical differences were found in demographic characteristics including age, body mass index or endometrial thickness. The PGR expression was reduced in FNC compared to IVF and HP-FET endometria (0.6 ± 0.1, 1.9 ± 0.9 and 2.2 ± 0.9 respectively; P < 0.0001). The PGR mRNA levels from ECC dissected by laser capture microdissection were higher in IVF and HP-ET cycles compared to FNC (10.6 ± 3.1, 13.6 ± 2.3 and 0.8 ± 0.1 respectively; P < 0.0001) corroborating the elevated PGR Hscore in EEC from ART cycles. Limitations, reasons for caution This is a descriptive study reporting failure of PGR downregulation in endometria from ART cycles with vaginal P4 supplementation during the luteal-phase. Whether interference or resistance to P4 signal is the mechanism involved in the failure of PGR down regulation in ART cycles needs to be determined Wider implications of the findings: PGR downregulation within EEC was shown in FNC. The retained PGR expression detected in most ART cycles may interfere with embryo implantation and might explain the restricted pregnancy success. Future studies might reveal whether PGR evaluation in EEC can predict embryo implantation. Trial registration number Not Aplicable


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