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31.
John?S?DavisEmail author Bo?R?Rueda Katherina?Spanel-Borowski 《Reproductive biology and endocrinology : RB&E》2003,1(1):89
The cyclic nature of the capillary bed in the corpus luteum offers a unique experimental model to examine the life cycle of
endothelial cells, involving discrete physiologically regulated steps of angiogenesis, blood vessel maturation and blood vessel
regression. The granulosa cells and theca cells of the developing antral follicle and the steroidogenic cells of the corpus
luteum produce and respond to angiogenic factors and vasoactive peptides. Following ovulation the neovascularization during
the early stages of corpus luteum development has been compared to the rapid angiogenesis observed during tumor formation.
On the other end of the spectrum, the microvascular endothelial cells are the first cells to undergo apoptosis at the onset
of corpus luteum regression. Important insights on the morphology and function of luteal endothelial cells have been gained
from a combination of in vitro and in vivo studies on endothelial cells. Endothelial cells communicate with cells comprising the functional unit of the corpus luteum,
i.e., other vascular cells, steroidogenic cells, and immune cells. This review is designed to provide an overview of the types
of endothelial cells present in the corpus luteum and their involvement in corpus luteum development and regression. Available
evidence indicates that microvascular endothelial cells of the corpus luteum are not alike, and may differ during the process
of angiogenesis and angioregression. The contributions of vasoactive peptides generated by the luteal endothelin-1 and the
renin-angiotensin systems are discussed in context with the function of endothelial cells during corpus luteum formation and
regression. The ability of two cytokines, tumor necrosis factor alpha and interferon gamma, are evaluated as paracrine mediators
of endothelial cell function during angioregression. Finally, chemokines are discussed as a vital endothelial cell secretory
products that contribute to the recruitment of eosinophils and macrophages. The review highlights areas for future investigation
of ovarian microvascular endothelial cells. The potential clinical applications of research directed on corpus luteum endothelial
cells are intriguing considering reproductive processes in which vascular dysfunctions may play a role such as ovarian failure,
polycystic ovary syndrome (PCOS), and ovarian hyperstimulation syndrome (OHSS). 相似文献
32.
James D. Darling Katherina Audley Ted Cheeseman Beth Goodwin Edward G. Lyman R. Jorge Urbn 《Biology letters》2022,18(2)
Humpback whales that assemble on winter breeding grounds in Mexico and Hawaii have been presumed to be, at least, seasonally isolated. Recently, these assemblies were declared Distinct Population Segments under the US Endangered Species Act. We report two humpback whales attending both breeding grounds in the same season—one moving from Hawaii to Mexico and the other from Mexico to Hawaii. The first was photo-identified in Maui, Hawaii on 23 February 2006 and again, after 53 days and 4545 km, on 17 April 2006 in the Revillagigedo Archipelago, Mexico. The second was photo-identified off Guerrero, Mexico on 16 February 2018 and again, 49 days and 5944 km later, on 6 April 2018 off Maui. The 2006 whale was identified in summer off Kodiak Island, Alaska; the 2018 whale off British Columbia. These Mexico–Hawaii identifications provide definitive evidence that whales in these two winter assemblies may mix during one winter season. This, combined with other lines of evidence on Mexico–Hawaii mixing, including interchange of individuals year to year, long-term similarity of everchanging songs, one earlier same-season travel record, and detection of humpback whales mid-ocean between these locations in winter, suggests reassessment of the ‘distinctiveness'' of these populations may be warranted. 相似文献
33.
Immobilized small-molecule inhibitors are suited for enrichment of biomolecules by affinity chromatography, as it is shown for metalloproteinases and an immobilizable derivative of the hydroxamate-type inhibitor marimastat. A new asymmetric synthesis of marimastat is presented that allows for site-specific attachment to a solid surface, e.g., a chromatography matrix or a surface plasmon resonance sensor chip. The latter technique is shown to be a valuable tool for the optimization of binding and elution conditons of biomolecules in affinity chromatography. 相似文献
34.
Nature employs a set of 20 amino acids to produce a repertoire of protein structures endowed with sophisticated functions. Here, we combined design and selection to create an enzyme composed entirely from a set of only 9 amino acids that can rescue auxotrophic cells lacking chorismate mutase. The simplified protein captures key structural features of its natural counterpart but appears to be somewhat less stable and more flexible. The potential of a dramatically reduced amino acid alphabet to produce an active catalyst supports the notion that primordial enzymes may have possessed low amino acid diversity and suggests that combinatorial engineering strategies, such as the one used here, may be generally applied to create enzymes with novel structures and functions. 相似文献
35.
36.
Jacob Debow Joshua Blouin Elias Rosenblatt Cedric Alexander Katherina Gieder Walter Cottrell James Murdoch Therese Donovan 《The Journal of wildlife management》2021,85(7):1423-1439
Moose (Alces alces) have experienced considerable declines along the periphery of their range in the northeastern United States. In Vermont, the population declined 45% from 2010 to 2017 despite minimal hunter harvest and adequate habitat. Similarly, nearby populations recently experienced epizootics characterized by >50% mortality. Declines have largely been associated with the effects of winter ticks (Dermacentor albipictus), but uncertainty exists about the effects of environmental and other parasite-related conditions on moose survival. We examined patterns of moose survival among a radio-collared population (n = 127) in Vermont from 2017 to 2019. Our objectives were to estimate causes of mortality and model survival probability as a function of individual and landscape variables for calves (<1 yr) and adults (≥1 yr). Observed adult survival was 90% in 2017, 84% in 2018, and 86% in 2019, and winter calf survival was 60% in 2017, 50% in 2018, and 37% in 2019. Winter tick infestation was the primary cause of mortality (91% of calves, 25% of adults), and 32% of all mortalities had evidence of meningeal worm (Parelaphostrongylus tenuis). Other sources of mortality such as vehicles, harvest, predation, deep snow, and other parasitic infections were negligible. The best supported calf model included sex differences and negative effects of tick engorgement (%/week) and parasite level (roundworm and lungworm). The best supported adult model included the effect of cumulative tick engorgement (cumulative %/week), which negatively affected survival. Our results indicate that winter tick engorgement strongly affects survival, and is probably compounded by the presence of meningeal worm and other parasites. Reduced tick effects may be achieved by decreasing moose density through harvest and managing late winter habitat to minimize tick density. Management of white-tailed deer (Odocoileus virginianus) density may also affect the transmission of meningeal worm. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society. 相似文献
37.
Sheehan Cristin E. Baker Kirralee G. Nielsen Daniel A. Petrou Katherina 《Hydrobiologia》2020,847(20):4233-4248
Hydrobiologia - Temperature plays a fundamental role in determining phytoplankton community structure, distribution, and abundance. With climate models predicting increases in ocean surface... 相似文献
38.
The advent of web-based treatments for anxiety disorders creates a need for quick and valid online screening instruments, suitable for a range of social groups. This study validates a single-item multimedia screening instrument for agoraphobia, part of the Visual Screener for Common Mental Disorders (VS-CMD), and compares it with the text-based agoraphobia items of the PDSS-SR. The study concerned 85 subjects in an RCT of the effects of web-based therapy for panic symptoms. The VS-CMD item and items 4 and 5 of the PDSS-SR were validated by comparing scores to the outcomes of the CIDI diagnostic interview. Screening for agoraphobia was found moderately valid for both the multimedia item (sensitivity.81, specificity.66, AUC.734) and the text-based items (AUC.607-.697). Single-item multimedia screening for anxiety disorders should be further developed and tested in the general population and in patient, illiterate and immigrant samples. 相似文献
39.
Diphtheria, caused by toxigenic strains of Corynebacterium diphtheriae, is an ancient disease with high incidence and mortality that has always been characterized by epidemic waves of occurrence. Whilst towards the beginning of the 1980s, many European countries were progressing towards the elimination of diphtheria, an epidemic re-emergence of diphtheria in the Russian Federation and the Newly Independent States of the former Soviet Union demonstrated a continuous threat of the disease into the 1990s. At present, the epidemic is under control and only sporadic cases are observed in Europe. However, the circulation of toxigenic strains is still observed in all parts of the world, posing a constant threat to the population with low levels of seroprotection. More recently, Corynebacterium ulcerans has been increasingly isolated as emerging zoonotic agent of diphtheria from companion animals such as cats or dogs, indicating the enduring threat of this thought-to-be controlled disease. 相似文献
40.
Evaluation of glucose transport and its regulation by insulin in human monocytes using flow cytometry. 总被引:2,自引:0,他引:2
George Dimitriadis Eirini Maratou Eleni Boutati Katherina Psarra Chryssa Papasteriades Sotirios A Raptis 《Cytometry. Part A》2005,64(1):27-33
BACKGROUND: We investigated the effects of insulin on glucose transport in human monocytes using flow cytometry, a method with several advantages over previously used techniques. We hypothesized that monocytes could be used as tools to study insulin action at the cellular level and facilitate the investigation of mechanisms that lead to insulin resistance. METHODS: Blood was withdrawn from 38 healthy subjects. The expression of glucose transporter (GLUT) isoforms in plasma membrane and the rates of glucose transport were determined with and without insulin (10 to 1,000 mU/L). Anti-CD14 phycoerythrin monoclonal antibody was used for monocyte gating. GLUT isoforms were determined after staining cells with specific antisera to GLUT1, GLUT3, and GLUT4. Glucose transport was monitored with 6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-6-deoxyglucose (NBDG). RESULTS: Insulin increased the uptake of NBDG (median effective dose 20 mU/L) and the expression of GLUT3 and GLUT4 isoforms in the plasma membrane (median effective doses 20 and 35 mU/L, respectively) but had no effect on GLUT1. Maximal effects were always reached at 100 mU/L of insulin. CONCLUSIONS: Monocytes may be a valid model system to study the effects of insulin on glucose transport. Further, flow cytometry is suitable for this investigation and can be used as an alternative to radiotracer methods. 相似文献