11,650 research outputs found
Calibration of the visible and near-infrared channels of the NOAA-9 AVHRR using high-altitude aircraft measurements from August 1985 and October 1986
Visible and near infrared wavelength sensors mounted on operational satellites now in use do not have onboard absolute calibration devices. One means of establishing an in-orbit calibration for a satellite sensor is to make simultaneous measurement of a bright, relatively uniform scene along the satellite view vector from a calibrated instrument on board a high altitude aircraft. Herein, aircraft data were recorded over White Sands, New Mexico at satellite overpass time. Comparison of the coincident aircraft and orbiting satellite data for the visible and near infrared wavelength channels of the NOAA-9 Advanced Very High Resolution Radiometer shows that the calibration of the visible channel was unchanged from prelaunch values, but that the near infrared channel has degraded 6 percent by Aug. 1985. By Oct. 1986 the visible channel had degraded 13 percent and the near infrared channel had degraded 19 percent
The Mammary Gland Microenvironment Directs Progenitor Cell Fate In Vivo
The mammary gland is a unique organ that continually undergoes postnatal developmental changes. In mice, the mammary gland is formed via signals from terminal end buds, which direct ductal growth and elongation. Intriguingly, it is likely that the entire cellular repertoire of the mammary gland is formed from a single antecedent cell. Furthermore, in order to produce progeny of varied lineages (e.g., luminal and myoepithelial cells), signals from the local tissue microenvironment influence mammary stem/progenitor cell fate. Data have shown that cells from the mammary gland microenvironment reprogram adult somatic cells from other organs (testes, nerve) into cells that produce milk and express mammary epithelial cell proteins. Similar results were found for human tumorigenic epithelial carcinoma cells. Presently, it is unclear how the deterministic power of the mammary gland microenvironment controls epithelial cell fate. Regardless, signals generated by the microenvironment have a profound influence on progenitor cell differentiation in vivo
A Potential Mechanism For Extracellular Matrix Induction of Breast Cancer Cell Normality
Extracellular matrix proteins from embryonic mesenchyme have a normalizing effect on cancer cells in vitro and slow tumor growth in vivo. This concept is suggestive of a new method for controlling the growth and spread of existing cancer cells in situ and indicates the possibility that extracellular proteins and/or embryonic mesenchymal fibroblasts may represent a fertile subject for study of new anti-cancer treatments
A Potential Mechanism for Extracellular Matrix Induction of Breast Cancer Cell Normality
Extracellular matrix proteins from embryonic mesenchyme have a normalizing effect on cancer cells in vitro and slow tumor growth in vivo. This concept is suggestive of a new method for controlling the growth and spread of existing cancer cells in situ and indicates the possibility that extracellular proteins and/or embryonic mesenchymal fibroblasts may represent a fertile subject for study of new anti-cancer treatments
Visible and near-infrared channel calibration of the GOES-6 VISSR using high-altitude aircraft measurements
Present and future visible and near-infrared wavelength sensors mounted on operational satellites do not have on-board absolute calibration devices. One means of establishing an in-orbit calibration for a satellite sensor is to make simultaneous measurements of a bright, relatively uniform scene along the satellite view vector from a calibrated instrument on board a high altitude aircraft. Aircraft data were recorded over White Sands, New Mexico, and the coincident aircraft and orbiting satellite data is compared for the visible and near-infrared wavelength channel of the GOES-6 Visible Infrared Spin-Scan Radiometer
What proportion of adult allergy referrals to secondary care could be dealt with in primary care by a GP with special interest?
Background: The concept of a General Practitioner with Special Interest (GPwSI) was first proposed in the 2000 National Health Service Plan, as a way of providing specialised treatment closer to the patient’s home and reducing hospital waiting times. Given the patchy and inadequate provision of allergy services in the UK the introduction of GPwSIs might reduce the pressure on existing specialist services. Objectives: This study assessed what proportion of referrals to a specialist allergy clinic could be managed in a GPwSI allergy service with a predefined range of facilities and expertise (accurate diagnosis and management of allergy; skin prick testing; provision of advice on allergen avoidance; ability to assess suitability for desensitisation). Methods: 100 consecutive GP referrals to a hospital allergy clinic were reviewed to determine whether patients could be seen in a community-based clinic led by a general practitioner with special interest (GPwSI) allergy. The documentation relating to each referral was independently assessed by three allergy specialists. The referrals were judged initially on the referral letter alone and then re-assessed with the benefit of information summarised in the clinic letter, to determine whether appropriate triage decisions could be made prospectively. The proportion of referrals suitable for a GPwSI was calculated and their referral characteristics identified. Results: 29 % referrals were judged unanimously appropriate for management by a GPwSI and an additional 30 % by 2 of the 3 reviewers. 18 % referrals were unsuitable for a GPwSI service because of the complexity of the presenting problem, patient co-morbidity or the need for specialist knowledge or facilities. Conclusions and clinical relevance: At least a quarter, and possibly half, of allergy referrals to our hospital-based service could be dealt with in a GPwSI clinic, thereby diversifying the patient pathway, allowing specialist services to focus on more complex cases and reducing the waiting time for first appointments
The future of mammary stem cell biology: the power of in vivo transplants – authors' response
Fragment screening reveals salicylic hydroxamic acid as an inhibitor of <em>Trypanosoma brucei</em> GPI GlcNAc-PI de-N-acetylase
The zinc-metalloenzyme GlcNAc-PI de-N-acetylase is essential for the biosynthesis of mature GPI anchors and has been genetically validated in the bloodstream form of Trypanosoma brucei, which causes African sleeping sickness. We screened a focused library of zinc-binding fragments and identified salicylic hydroxamic acid as a GlcNAc-PI de-N-acetylase inhibitor with high ligand efficiency. This is the first small molecule inhibitor reported for the trypanosome GPI pathway. Investigating the structure activity relationship revealed that hydroxamic acid and 2-OH are essential for potency, and that substitution is tolerated at the 4- and 5-positions
Paracrine-Rescued Lobulogenesis in Chimeric Outgrowths Comprising Progesterone-Receptor-Null Mammary Epithelium and Redirected Wild-Type Testicular Cells
We have previously shown that non-mammary and tumorigenic cells can respond to the signals of the mammary niche and alter their cell fate to that of mammary epithelial progenitor cells. Here we tested the hypothesis that paracrine signals from mammary epithelial cells expressing progesterone receptor (PR) are dispensable for redirection of testicular cells, and that re-directed wild-type testicular-derived mammary cells can rescue lobulogenesis of PR-null mammary epithelium by paracrine signaling during pregnancy. We injected PR-null epithelial cells mixed with testicular cells from wild-type adult male mice into cleared fat-pads of recipient mice. The testicular cells were redirected in vivo to mammary epithelial cell fate during regeneration of the mammary epithelium, and persisted in second-generation outgrowths. In the process, the redirected testicular cells rescued the developmentally deficient PR-null cells, signaling them through the paracrine factor RANKL to produce alveolar secretory structures during pregnancy. This is the first demonstration that paracrine signaling required for alveolar development is not required for cellular reprogramming in the mammary gland, and that reprogrammed testicular cells can provide paracrine signals to the surrounding mammary epithelium
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