120 research outputs found
A Multivariate Craniometric Analysis of Secular Change and Variation Among Recent North American Populations
This study presents an investigation of secular trends in craniometric variation among Afro-American and Euro-American North American populations from 1750 to the present. An additional analysis of collection specific cranial variation between two prominent anatomical collections is also undertaken. Both investigations address the question of crania variation in reference to the proper application of craniometric analysis to medico-legal identiciation of racial affiliation in forensic anthropology.
The craniometric data include individual historic specimens and cemetery populations from Canada, Philadelphia and New Orleans. Anatomical specimens are collected from the Hamann-Todd and R. J. Terry collections, and recent forensic cases are obtained from forensic laboratories across the nation.
Predicated on the idea that secular change in cranial size and shape contribute to the differentiation between temporally different crania series, it is suggested that temporally earlier cranial series are less appropriate as calibration samples for the identification of contemporary U.S. populations. Analyses were performed on eighty crania variables to document temporal differences among racial and ethnic groups, and to explore patterns of variation related to gender within each group. Group differences were examined by multivariate analysis of variance and temporal differences were investigated using multivariate analysis of covariance and canonical correlation. Specificity of collection association was examined by canonical discriminant analysis.
The multivariate analysis of cranial variation revealed similar temporal trends in size and shape between Afro-American female and male crania, while Euro-American gender differed somewhat in their direction of change. Temporal trends and collection specificity are both statistically significant. Collections are suggested to reflect ethnic differences, particularly within the Euro-American group.
It is found that significant temporal changes among Afro-American and Euro-American cranial series and ethnic specificity of individual skeletal collections can render problematic the application of earlier cranial series to the identification of recent forensic cases.
An alternative to present calibration standards for forensic identification of crania is offered. Two additional cranial series of Hispanic-American males and American Indian of both sexes were added to the sample to define a four group calibration sample.
Calibration standards were calculated using discriminant analysis for the separation of racial or ethnic groups. Four, three and two group discriminant function were calculated for a suple of post 1900 crania to conclude the analysis
Mucinous Cystic Neoplasm of Pancreas in a Pregnant Woman Presenting with Severe Anemia and Gastric Bleeding: Case Report and Review of the Literature
Mucinous cystic neoplasms of the pancreas are uncommon and especially their occurrence during pregnancy is an extremely rare event which necessitates an individualized and interdisciplinary management. A 33-year old woman was referred to our department during her third trimester of pregnancy (34th week of gestation) with severe anemia and tarry stools. Based on gastroscopic findings, our interdisciplinary team suspected a gastrointestinal stromal tumor and therefore indicated a prompt delivery via cesarean section completed with an oncological resection of the neoplasm. Histological examination subsequently showed a mucinous cystic neoplasm of the pancreas with no evidence of malignancy. To review the prevalence of mucinous cystic neoplasms and to discuss diagnosis and treatment during pregnancy. Moreover, we critically value the indication of preterm delivery and the oncological procedure in the perspective of outcome for mother and infant. A bleeding gastrointestinal tumor during pregnancy represents a life-threatening risk for mother and infant and requires an immediate interdisciplinary treatment. The urgency and radicality of the therapy should be adapted according to individual findings. As our patient's tumor was suspected of having a malignant progression, an extensive surgical intervention was necessary
Quenched autoligation probes allow discrimination of live bacterial species by single nucleotide differences in rRNA
Quenched autoligation (QUAL) probes are a class of self-reacting nucleic acid probes that give strong fluorescence signal in the presence of fully complementary RNAs and selectivity against single nucleotide differences in solution. Here, we describe experiments designed to test whether QUAL probes can discriminate between bacterial species by the detection of small differences in their 16S rRNA sequences. Probes were introduced into live cells using small amounts of detergent, thus eliminating the need for fixation, and fluorescence signal was monitored both by microscopy and by flow cytometry without any washing steps. The effects of probe length, modified backbone, probe concentration and growth state of the bacteria were investigated. The data demonstrate specific fluorescence discrimination between three closely related bacteria, Escherichia coli, Salmonella enterica and Pseudomonas putida, based on single nucleotide differences in their 16S rRNA. Discrimination was possible with cells in mid-log phase or in lag phase. These results suggest that QUAL probes may be useful for rapid identification of microorganisms in laboratory and clinical settings
Re-interpreting plant morphological responses to UV-B radiation
There is a need to reappraise the effects of UV-B radiation on plant morphology in light of improved mechanistic understanding of UV-B effects, particularly elucidation of the UV RESISTANCE LOCUS 8 (UVR8) photoreceptor. We review responses at cell and organismal levels, and explore their underlying regulatory mechanisms, function in UV protection and consequences for plant fitness. UV-induced morphological changes include thicker leaves, shorter petioles, shorter stems, increased axillary branching and altered root:shoot ratios. At the cellular level, UV-B morphogenesis comprises changes in cell division, elongation and/or differentiation. However, notwithstanding substantial new knowledge of molecular, cellular and organismal UV-B responses, there remains a clear gap in our understanding of the interactions between these organizational levels, and how they control plant architecture. Furthermore, despite a broad consensus that UV-B induces relatively compact architecture, we note substantial diversity in reported phenotypes. This may relate to UV-induced morphological changes being underpinned by different mechanisms at high and low UV-B doses. It remains unproven whether UV-induced morphological changes have a protective function involving shading and decreased leaf penetration of UV-B, counterbalancing trade-offs such as decreased photosynthetic light capture and plant-competitive abilities. Future research will need to disentangle seemingly contradictory interactions occurring at the threshold UV dose where regulation and stress-induced morphogenesis overlap. We review the effects of UV-B on plant morphology, using the improved mechanistic understanding of UV perception and signalling following elucidation of the UVR8 photoreceptor to reappraise published results. Despite a substantially improved understanding of molecular, cellular and organismal UV-B responses, there remains a clear gap in our knowledge of the interactions between these organisational levels, their function in UV-protection, and consequences for plant fitness and plant-plant interactions. Future research will need to disentangle the seemingly contradictory interactions and substantial diversity in reported phenotypes that occur at the threshold UV dose where regulation and stress-induced morphogenesis overlap.Peer reviewe
Deconstruction of the (Paleo)Polyploid Grapevine Genome Based on the Analysis of Transposition Events Involving NBS Resistance Genes
Plants have followed a reticulate type of evolution and taxa have frequently merged via allopolyploidization. A polyploid structure of sequenced genomes has often been proposed, but the chromosomes belonging to putative component genomes are difficult to identify. The 19 grapevine chromosomes are evolutionary stable structures: their homologous triplets have strongly conserved gene order, interrupted by rare translocations. The aim of this study is to examine how the grapevine nucleotide-binding site (NBS)-encoding resistance (NBS-R) genes have evolved in the genomic context and to understand mechanisms for the genome evolution. We show that, in grapevine, i) helitrons have significantly contributed to transposition of NBS-R genes, and ii) NBS-R gene cluster similarity indicates the existence of two groups of chromosomes (named as Va and Vc) that may have evolved independently. Chromosome triplets consist of two Va and one Vc chromosomes, as expected from the tetraploid and diploid conditions of the two component genomes. The hexaploid state could have been derived from either allopolyploidy or the separation of the Va and Vc component genomes in the same nucleus before fusion, as known for Rosaceae species. Time estimation indicates that grapevine component genomes may have fused about 60 mya, having had at least 40–60 mya to evolve independently. Chromosome number variation in the Vitaceae and related families, and the gap between the time of eudicot radiation and the age of Vitaceae fossils, are accounted for by our hypothesis
Skewed X-inactivation is common in the general female population
X-inactivation is a well-established dosage compensation mechanism ensuring that X-chromosomal genes are expressed at comparable levels in males and females. Skewed X-inactivation is often explained by negative selection of one of the alleles. We demonstrate that imbalanced expression of the paternal and maternal X-chromosomes is common in the general population and that the random nature of the X-inactivation mechanism can be sufficient to explain the imbalance. To this end, we analyzed blood-derived RNA and whole-genome sequencing data from 79 female children and their parents from the Genome of the Netherlands project. We calculated the median ratio of the paternal over total counts at all X-chromosomal heterozygous single-nucleotide variants with coverage ≥10. We identified two individuals where the same X-chromosome was inactivated in all cells. Imbalanced expression of the two X-chromosomes (ratios ≤0.35 or ≥0.65) was observed in nearly 50% of the population. The empirically observed skewing is explained by a theoretical model where X-inactivation takes place in an embryonic stage in which eight cells give rise to the hematopoietic compartment. Genes escaping X-inactivation are expressed from both alleles and therefore demonstrate less skewing than inactivated genes. Using this characteristic, we identified three novel escapee genes (SSR4, REPS2, and SEPT6), but did not find support for many previously reported escapee genes in blood. Our collective data suggest that skewed X-inactivation is common in the general population. This may contribute to manifestation of symptoms in carriers of recessive X-linked disorders. We recommend that X-inactivation results should not be used lightly in the interpretation of X-linked variants
Veränderungen im Wohlbefinden von Erstspendern durch die Blutspende und deren Auswirkungen auf die Wiederkehrrate
Background and objectives
Previous studies observed a transient increase in well-being in about one-third of regular donors after blood donation. In addition, personal contact with donors after donation seems to increase return rates. We were interested whether changes in well-being and/or personal contact after the first donation impact return rates of first-time donors (FTDs).
Materials and methods
First-time donors were randomized to a questionnaire group (QG), in which questionnaires assessing the well-being had to be filled in, or a control group (CG), which was not contacted with a questionnaire. The QG had to complete the same questionnaire three times at the day of the first donation and then four times over an 8-week period with reminding calls by the study coordinator. Return rates of participants were followed for 12 months.
Results
A total of 102 FTDs participated in the QG and 115 in the CG. Changes in well-being after the first donation had minimal impact on the return rates. In contrast, contacting FTDs after their first donation had a significant impact on the return rate of male donors (89!2% in the QG vs. 58!3% in the CG; P = 0.001). Females showed no significant difference in return rates between both groups (P = 0.32).
Conclusion
The well-being of FTDs had no influence on their return rate. The intervention of regular contacts during a research project follow-up resulted in an increased return rate of male but not of female FTDs. The pronounced difference of the impact of this intervention between male and female donors requires further studies.Der Bedarf an Blutprodukten ist in den letzten Jahren gestiegen, während der Kreis der möglichen Blutspender bei alternder Bevölkerung abgenommen hat und weiter abnehmen wird. Blutspende-Einrichtungen betreiben viel Aufwand, Blutspender zu gewinnen und als Dauerspender zu binden. Frühere Studien zeigten, dass ein Drittel der Dauerspender ein positives „Well-being“ nach der Spende erfahren und dies als Grund für regelmäßige Blutspenden angeben. In dieser Studie wurde ntersucht, ob ein „Well-being“ auch bereits bei Erstspender ausgeprägt ist und ob dies einen Einfluss auf das Rückkehrverhalten von Erstspendern hat. Zusätzlich sollte gezeigt werden, dass die Studie als Intervention einen Einfluss auf das Rückkehrverhalten bei Erstspendern hat. Über drei aufeinander folgende Monate wurden 235 Erstspender in die Studie eingeschlossen und entweder in die Fragebogengruppe oder in die Kontrollgruppe randomisiert. Bei allen Studienteilnehmern wurde zwölf Monate nach der initialen Spende deren Rückkehrverhalten ausgewertet. Die Teilnehmer der Fragebogengruppe sollten zusätzlich zu sieben verschiedenen Zeitpunkten, verteilt über acht Wochen, den „Multidimensionalen Befindlichkeitsfragebogen“ ausfüllen. An Hand der Ergebnisse des MDBF sollte der Verlauf des „Well-being“ aufgezeigt werden. Folgende Ergebnisse wurden erhoben: Erstspender scheinen keine größeren Veränderungen des „Well-beings“ nach ihrer ersten Blutspende zu erfahren. Des Weiteren beeinflusste das „Well-being“ nicht das Rückkehrverhalten der Erstspender. Die durchgeführten Interventionen führten zu einer erhöhten Wiederkehrrate der männlichen Erstspender, nicht jedoch der weiblichen Erstspender. Um eine praktikable Schlussfolgerung aus den Ergebnissen dieser Studie ziehen zu können, sollten zukünftige Studien den hier in der Wiederkehrrate aufgetretenen Geschlechterunterschied spezifischer untersuchen. Interessant wäre vor allem, welche der durchgeführten Interventionen oder eine Kombination aus diesen zu der gesteigerten Wiederkehrrate männlicher Erstspender geführt hat. Mit Hilfe weiterführender Ergebnisse wäre es dann möglich, gezielt Interventionen zu betreiben, die effizient die Spendefrequenz der Blutspender erhöht
Comparison of fMRI paradigms assessing visuospatial processing: Robustness and reproducibility
The development of brain imaging techniques, in particular functional magnetic resonance imaging (fMRI), made it possible to non-invasively study the hemispheric lateralization of cognitive brain functions in large cohorts. Comprehensive models of hemispheric lateralization are, however, still missing and should not only account for the hemispheric specialization of individual brain functions, but also for the interactions among different lateralized cognitive processes (e.g., language and visuospatial processing). This calls for robust and reliable paradigms to study hemispheric lateralization for various cognitive functions. While numerous reliable imaging paradigms have been developed for language, which represents the most prominent left-lateralized brain function, the reliability of imaging paradigms investigating typically right-lateralized brain functions, such as visuospatial processing, has received comparatively less attention. In the present study, we aimed to establish an fMRI paradigm that robustly and reliably identifies right-hemispheric activation evoked by visuospatial processing in individual subjects. In a first study, we therefore compared three frequently used paradigms for assessing visuospatial processing and evaluated their utility to robustly detect right-lateralized brain activity on a single-subject level. In a second study, we then assessed the test-retest reliability of the so-called Landmark task-the paradigm that yielded the most robust results in study 1. At the single-voxel level, we found poor reliability of the brain activation underlying visuospatial attention. This suggests that poor signal-to-noise ratios can become a limiting factor for test-retest reliability. This represents a common detriment of fMRI paradigms investigating visuospatial attention in general and therefore highlights the need for careful considerations of both the possibilities and limitations of the respective fMRI paradigm-in particular, when being interested in effects at the single-voxel level. Notably, however, when focusing on the reliability of measures of hemispheric lateralization (which was the main goal of study 2), we show that hemispheric dominance (quantified by the lateralization index, LI, with |LI| >0.4) of the evoked activation could be robustly determined in more than 62% and, if considering only two categories (i.e., left, right), in more than 93% of our subjects. Furthermore, the reliability of the lateralization strength (LI) was "fair" to "good". In conclusion, our results suggest that the degree of right-hemispheric dominance during visuospatial processing can be reliably determined using the Landmark task, both at the group and single-subject level, while at the same time stressing the need for future refinements of experimental paradigms and more sophisticated fMRI data acquisition techniques
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