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At least 73 records · Page 4Linked to original sources
PubMed1996

Purification of primordial germ cells from TNAPbeta-geo mouse embryos using FACS-gal.

Tissue nonspecific alkaline phosphatase (TNAP), the product of the Akp2 locus, is expressed in mouse primordial germ cells (PGC) for an extensive period during embryogenesis. Mice with the Akp2tm1Sor mutant allele of TNAP express lacZ (beta-galactosidase; beta-gal) under control of the Akp2 locus. PGCs were purified from Akp2tm1Sor embryos using fluorescence activated cell sorting of beta-gal expressing cells (FACS-gal). Analysis of the purified cells by alkaline phosphatase staining and immunocytochemistry with anti-c-kit antibody demonstrated that highly (98%) purified PGCs can be isolated using this method. This technique will facilitate experiments that require highly purified preparations of PGCs including cell culture and gene expression analyses.

Alkaline Phosphatase↗
PubMed1998

Efficient gene trap screening for novel developmental genes using IRES beta geo vector and in vitro preselection.

We have used different gene trap vectors and in vitro preselection of embryonic stem (ES) cells for a large scale screening of insertional mutations in developmentally regulated genes. A gene trap vector was constructed, which contains an internal ribosome entry site (IRES) upstream from a betageo selectable-reporter fusion gene. Analysis of 801 independent integrations revealed that the IRESbetageo vector allows for a global enrichment of about 15 folds in the number of detectable gene trap events when compared with a conventional betageo vector. Characterization of in vitro and in vivo lacZ expression suggested that this IRES-based vector is able to capture a wide range of genes expressed in a variety of tissues and developmental stages, and it can also allow trapping of genes expressed at very low levels in ES cells. A preselection protocol was devised, where gene-trapped ES cells were grown in the presence of specific growth/differentiation factors such as follistatin, nerve growth factor, and retinoic acid. Several gene trap integrations were found to be either activated or repressed by one of these factors. Characterization of lacZ expression during embryogenesis showed a strong enrichment of restricted patterns in vivo after ES cell preselection. These results suggest that a combination of IRESbetageo vector and in vitro preselection is more effective for the capture and mutation of a large number of developmental genes.

Animals↗
PubMed2006

Origin assignment of unidentified corpses by use of stable isotope ratios of light (bio-) and heavy (geo-) elements--a case report.

An unknown male body was found near an expressway in Germany. As different criminalistic and forensic methods (e.g. tooth status, fingerprint or DNA-analysis) could not help to identify the person, multielement stable isotope investigations were applied. The combined analysis of stable isotope ratios of light (H, C, N) and heavy elements (Pb, Sr) on the man's body tissues supported to assign him to Romania. The case report demonstrates an application of multielement-isotope analysis in the forensic fields and its potential.

Bone and Bones↗
PubMed2004

90Sr migration to the geo-sphere from a waste burial in the Chernobyl exclusion zone.

Results are presented from an ongoing field-scale experimental study (namely the Chernobyl Pilot Site project) aimed at characterization of processes controlling (90)Sr releases from a shallow trench containing nuclear fuel particles, and subsequent radionuclide transport in the underlying sandy aquifer at the Chernobyl nuclear power plant site. Microscopic analyses of waste material and leaching experiments have shown that 10-30% of the radioactive inventory is associated with chemically extra-stable Zr-U-O particles. The largest fraction of (90)Sr activity in the trench ( approximately 30-60%) is currently associated with relatively slowly dissolving non-oxidized UO(2) matrix fuel particles. The (90)Sr migration velocity in the eolian sand aquifer is retarded by sorption to approximately 9% of groundwater flow velocity (K(d) approximately 2 ml/g). The dispersivity values for non-reactive solute transport in the aquifer predicted by geostatistics (i.e. 0.8 6 cm) were confirmed by a natural gradient tracer test using (36)Cl. The observed negative correlation between hydraulic conductivity and K(d) of aquifer sediments suggests that (90)Sr could be subjected to larger dispersion in the subsurface compared with (36)Cl.

Environmental Monitoring↗
PubMedDate not supplied

A chest injury in an isolated geo-politically sensitive area: questions in management.

The reported case of a stab wound to the chest occurred in an isolated area with no specialized surgical care available. The need for transport and specifically by air, introduced particular questions in management. On a humanitarian basis and in line with its mandate, the Peace Monitoring Group, a United Nations endorsed entity in Bougainville, Papua New Guinea, provided transport to a facility with an appropriate standard of care. The questions of need for patient evacuation and chest drainage, with the timing of this maneuver are considered.

Adult↗
PubMed2004

Visualization for constructing and sharing geo-scientific concepts.

Representations of scientific knowledge must reflect the dynamic nature of knowledge construction and the evolving networks of relations between scientific concepts. In this article, we describe initial work toward dynamic, visual methods and tools that support the construction, communication, revision, and application of scientific knowledge. Specifically, we focus on tools to capture and explore the concepts that underlie collaborative science activities, with examples drawn from the domain of human-environment interaction. These tools help individual researchers describe the process of knowledge construction while enabling teams of collaborators to synthesize common concepts. Our visualization approach links geographic visualization techniques with concept-mapping tools and allows the knowledge structures that result to be shared through a Web portal that helps scientists work collectively to advance their understanding. Our integration of geovisualization and knowledge representation methods emphasizes the process through which abstract concepts can be contextualized by the data, methods, people, and perspectives that produced them. This contextualization is a critical component of a knowledge structure, without which much of the meaning that guides the sharing of concepts is lost. By using the tools we describe here, human-environment scientists are given a visual means to build concepts from data (individually and collectively) and to connect these concepts to each other at appropriate levels of abstraction.

Environment↗
PubMed1984

Image Analysis of Geo-Induced Inhibition, Compression, and Promotion of Growth in an Inverted Helianthus annuus L. Seedling.

The growth responses of a sunflower seedling (Helianthus annuus L.), subjected to repeated inversion, were characterized by time-lapse recording in conjunction with video image analysis. The investigation revealed a characteristic response pattern and established that the directional movement of the seedling is achieved by both inhibition and stimulation of growth in the normal growing regions. The complex growth changes in contiguous regions of the hypocotyl are such as seem to be inexplicable in terms of an environmentally imposed gradient of a single growth substance.

Journal Article↗
PubMed2006

Investigation of geo-spatial hotspots for the occurrence of tuberculosis in Almora district, India, using GIS and spatial scan statistic.

BACKGROUND: The World Health Organization has declared tuberculosis a global emergency in 1993. It has been estimated that one third of the world population is infected with Mycobacterium tuberculosis, the causative agent of tuberculosis. The emergence of TB/HIV co-infection poses an additional challenge for the control of tuberculosis throughout the world. The World Health Organization is supporting many developing countries to eradicate tuberculosis. It is an agony that one fifth of the tuberculosis patients worldwide are in India. The eradication of tuberculosis is the greatest public health challenge for this developing country. The aim of the present population based study on Mycobacterium tuberculosis is to test a large set of tuberculosis cases for the presence of statistically significant geographical clusters. A spatial scan statistic is used to identify purely spatial and space-time clusters of tuberculosis. RESULTS: Significant (p < 0.05 for primary clusters and p < 0.1 for secondary clusters) high rate spatial and space-time clusters were identified in three areas of the district. CONCLUSION: There is sufficient evidence about the existence of statistically significant tuberculosis clusters in Almora district of Uttaranchal, India. The spatial scan statistics methodology used in this study has a potential use in surveillance of tuberculosis for detecting the true clusters of the disease.

Cluster Analysis↗
PubMed2006

Effect of chest X-rays on the risk of breast cancer among BRCA1/2 mutation carriers in the international BRCA1/2 carrier cohort study: a report from the EMBRACE, GENEPSO, GEO-HEBON, and IBCCS Collaborators' Group.

PURPOSE: Women who carry germline mutations in the BRCA1 and BRCA2 genes are at greatly increased risk of breast cancer (BC). Numerous studies have shown that moderate to high doses of ionizing radiation are a risk factor for BC. Because of the role of the BRCA proteins in DNA repair, we hypothesized that BRCA carriers might be more sensitive to ionizing radiation than women in the general population. PATIENTS AND METHODS: A retrospective cohort study of 1,601 female BRCA1/2 carriers was performed. Risk of breast cancer from exposure to chest x-rays, as assessed by questionnaire data, was analyzed using a weighted Cox proportional hazards model. RESULTS: In this cohort, any reported exposure to chest x-rays was associated with an increased risk of BC (hazard ratio [HR] = 1.54; P = .007). This risk was increased in carrier women aged 40 years and younger (HR = 1.97; P < .001) and in women born after 1949 (HR = 2.56; P < .001), particularly those exposed only before the age of 20 years (HR = 4.64; P < .001). CONCLUSION: In our series of BRCA carriers, we detected a relatively large effect on BC risk with a level of radiation exposure that is at least an order of magnitude lower than in previously studied medical radiation-exposed cohorts. Although part of this increase may be attributable to recall bias, the observed patterns of risk in terms of age at exposure and attained age are consistent with those found in previous studies. If confirmed, the results have important implications for the use of x-ray imaging in young BRCA1/2 carriers.

Adult↗
PubMed2017

Smoking and Lung Cancer: A Geo-Regional Perspective.

Lung cancer is the leading cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) represents the most frequently diagnosed subtype of this morbid malignancy. NSCLC is causally linked to tobacco consumption with more than 500 million smokers worldwide at high risk for this fatal malignancy. We are currently lagging in our knowledge of the early molecular (e.g., genomic) effects of smoking in NSCLC pathogenesis that would constitute ideal markers for early detection. This limitation is further amplified when considering the variable etiologic factors in NSCLC pathogenesis among different regions around the globe. In this review, we present our current knowledge of genomic alterations arising during early stages of smoking-induced lung cancer initiation and progression, including discussing the premalignant airway field of injury induced by smoking. The review also underscores the wider spectra and higher age-adjusted rates of tobacco (e.g., water-pipe smoke) consumption, along with elevated environmental carcinogenic exposures and relatively poorer socioeconomic status, in low-middle income countries (LMICs), with Lebanon as an exemplar. This "cocktail" of carcinogenic exposures warrants the pressing need to understand the complex etiology of lung malignancies developing in LMICs such as Lebanon.

early detection↗
PubMed1999

Evidence of genocide 7000 BP--Neolithic paradigm and geo-climatic reality.

The early Neolithic fortified settlement of Schletz, Lower Austria is emerging as one of the most interesting sites of Linear Pottery culture excavation in Austria. In the course of systematic investigations carried out since 1983, a plethora of unexpected results have been obtained. Specifically, the human skeletal remains of 67 individuals have been found at the base of an oval trench system. Without exception, these remains are characterized by multiple traumatic lesions as well as carnivore gnaw marks. Demographic analysis presents the picture of the entire population of this early farming settlement having been extinguished. Further, the findings suggest that a genocide scenario may have been responsible for the final demise of this settlement. The age and sex distribution reveals a lack of young females, who are interpreted as having been abducted by aggressors. There is however no direct skeletal evidence of aggressors at the site; in fact, the uniformity of Strontium isotope ratios (HR-ICP-MS analysis) implies that all 67 individuals, who were left unburied for months, were indigenous. Supporting evidence of increased levels of inter-human aggression--possibly caused by a broad wave of migration--comes from other contemporary end linear pottery sites in Germany. Such findings are here discussed in the context of a dramatic geological event in the region of the Black Sea shelf at this time (7.550 BP), which led to the submergence of some 100.000 square kilometers of fertile land, and which might have been responsible for subsequent gradual population movements into the interior of Europe.

Animals↗