2,551 research outputs found
Molecular investigations in the role of the GALK1 Gene in Galactokinase Deficiency
Galactokinase deficiency is an autosomal-recessive inborn error of galactose metabolism whose major clinical manifestation is the development of cataracts during the first months of life. This metabolic disorder is caused by defects in the first enzyme of the Leloir pathway, galactokinase, encoded by the gene GALK1 on chromosome 17q24. Despite the identification of a number of conserved domains in GALK1, understanding of the functional significance of these regions and the molecular basis of the disorder is limited. This is largely due to the rarity of the disease and the fact that the small number of GALK1 mutations identified to-date are confined to individual families, thus precluding extensive genotype/phenotype correlations. The current investigation involved an analysis of the GALK1 gene in nine patients with biochemical phenotypes indicative of classical galactokinase deficiency. Sequencing of the entire coding region, flanking intronic sequence and both the 5\u27UIR and 3’UTR of GALK1 using Dye Terminator chemistry and the ABI377 DNA Analyzer, revealed four novel mutations in two unrelated patients with galactokinase deficiency. Three of these were amino acid substitutions: 1569C→ Tin exon 2 (R68C), 7093C→ Tin exon 6 (f288M) and 7538G→ C in exon 8 (A384P). In addition, a single base deletion was found in exon 5 (2833delC), predicted to result in a shift of the reading frame and a premature termination codon at position 263. Sequence analysis in a third patient detected a 563C→ A transversion (P28T), previously identified as a common mutation in six Bulgarian Gypsy families (Kalaydjieva et al., 1999). The remaining six patients, belonging to socially and geographically dispersed Gypsy groups from Spain, Hungary and Bulgaria were screened for P28T using a PCR-based Ava I restriction assay. All were homozygous for P28T. Haplotype analysis established a common origin of the mutation, providing further evidence that P28T is a founder mutation among patients with Gypsy ethnicity and signaling the mutation is more widespread than initial indications suggest. To determine the carrier frequency and distribution of the P28T mutation, 227 unrelated individuals originating from various Gypsy groups in Europe, were screened using the Ava I assay. Carrier frequency in the Vlax Roma was calculated at 2.7% and 1.8% in Spanish Gypsies. These results indicate that the prevalence of the P28T mutation warrants further investigation preceeding the development of newborn screening strategies and dietary intervention in these groups in a bid to prevent infantile blindness. The findings also allow the identification of a large sample of carriers suitable for future investigations into genotype/ phenotype correlations. Sequence analysis of the GALK1 gene in two Afro/Hispanic patients presenting with a rare atypical phenotype with metabolic symptoms of galactokinase deficiency and normal RBC galactokinase activity, revealed no plausible disease-causing mutations. In fact, lack of similarity in the GALK1 gene in both patients, despite sharing a common ethnic background, suggested exclusion of GALK1 in this phenotype
A multi-scale assessment of amphibian habitat selection: Wood frog response to timber harvesting
To understand changes in habitat selection in response to timber harvesting, we used radio-telemetry data from 82 adult wood frogs (Lithobates sylvaticus, formerly Rana sylvatica) and logistic regression modelling to assess habitat selection in response to an unharvested control and 3 forest management techniques: clearcutting (with removal of all merchantable timber \u3e 10 cm diameter), clearcutting with coarse woody debris (CWD) retention, and partial harvesting with retention of ∼50% canopy cover. At the home range scale, frogs selected the partially harvested treatment in spring 2005 and avoided the CWD-retained treatment in fall 2006. Frogs spent 5 ± 2 d (mean ± SE) longer in forested treatments than in both clearcut treatments, but certain individuals were able to specialize on the clearcut treatments. At the weekly activity centre scale, the best-supported models indicated that frogs were more likely to occupy locations with more complex ground structure, especially coarse woody debris, warmer temperatures, moister substrates, and greater canopy cover than random. Resource use among frogs overlapped substantially at both the weekly activity centre and daily microhabitat scales. Frogs selected daily microhabitats with more complex ground structure, greater canopy cover, and moister substrates than random. Selection at coarser scales may be mechanistically linked to finer scale resource selection by the physiological processes of thermoand hydro-regulation. Our results support recommendations for minimizing the impact of logging by retaining coarse woody debris in clearcuts and partial harvesting with retention of ∼50% canopy cover
M–M Bond-Stretching Energy Landscapes for M_2(dimen)_(4)^(2+) (M = Rh, Ir; dimen = 1,8-Diisocyanomenthane) Complexes
Isomers of Ir_2(dimen)_(4)^(2+) (dimen = 1,8-diisocyanomenthane) exhibit different Ir–Ir bond distances in a 2:1 MTHF/EtCN solution (MTHF = 2-methyltetrahydrofuran). Variable-temperature absorption data suggest that the isomer with the shorter Ir–Ir distance is favored at room temperature [K = ~8; ΔH° = −0.8 kcal/mol; ΔS° = 1.44 cal mol^(–1) K^(–1)]. We report calculations that shed light on M_2(dimen)_(4)^(2+) (M = Rh, Ir) structural differences: (1) metal–metal interaction favors short distances; (2) ligand deformational-strain energy favors long distances; (3) out-of-plane (A_(2u)) distortion promotes twisting of the ligand backbone at short metal–metal separations. Calculated potential-energy surfaces reveal a double minimum for Ir_2(dimen)_(4)^(2+) (4.1 Å Ir–Ir with 0° twist angle and ~3.6 Å Ir–Ir with ±12° twist angle) but not for the rhodium analogue (4.5 Å Rh–Rh with no twisting). Because both the ligand strain and A_(2u) distortional energy are virtually identical for the two complexes, the strength of the metal–metal interaction is the determining factor. On the basis of the magnitude of this interaction, we obtain the following results: (1) a single-minimum (along the Ir–Ir coordinate), harmonic potential-energy surface for the triplet electronic excited state of Ir_2(dimen)_(4)^(2+) (R_(e,Ir–Ir) = 2.87 Å; F_(Ir–Ir) = 0.99 mdyn Å^(–1)); (2) a single-minimum, anharmonic surface for the ground state of Rh_2(dimen)_(4)^(2+) (R_(e,Rh–Rh) = 3.23 Å; F_(Rh–Rh) = 0.09 mdyn Å^(–1)); (3) a double-minimum (along the Ir–Ir coordinate) surface for the ground state of Ir_2(dimen)_(4)^(2+) (R_(e,Ir–Ir) = 3.23 Å; F_(Ir–Ir) = 0.16 mdyn Å^(–1))
Cas Adaptor Proteins Coordinate Sensory Axon Fasciculation.
Development of complex neural circuits like the peripheral somatosensory system requires intricate mechanisms to ensure axons make proper connections. While much is known about ligand-receptor pairs required for dorsal root ganglion (DRG) axon guidance, very little is known about the cytoplasmic effectors that mediate cellular responses triggered by these guidance cues. Here we show that members of the Cas family of cytoplasmic signaling adaptors are highly phosphorylated in central projections of the DRG as they enter the spinal cord. Furthermore, we provide genetic evidence that Cas proteins regulate fasciculation of DRG sensory projections. These data establish an evolutionarily conserved requirement for Cas adaptor proteins during peripheral nervous system axon pathfinding. They also provide insight into the interplay between axonal fasciculation and adhesion to the substrate
Why do some women still prefer traditional birth attendants and home delivery?: a qualitative study on delivery care services in West Java Province, Indonesia
<p>Abstract</p> <p>Background</p> <p>Trained birth attendants at delivery are important for preventing both maternal and newborn deaths. West Java is one of the provinces on Java Island, Indonesia, where many women still deliver at home and without the assistance of trained birth attendants. This study aims to explore the perspectives of community members and health workers about the use of delivery care services in six villages of West Java Province.</p> <p>Methods</p> <p>A qualitative study using focus group discussions (FGDs) and in-depth interviews was conducted in six villages of three districts in West Java Province from March to July 2009. Twenty FGDs and 165 in-depth interviews were conducted involving a total of 295 participants representing mothers, fathers, health care providers, traditional birth attendants and community leaders. The FGD and in-depth interview guidelines included reasons for using a trained or a traditional birth attendant and reasons for having a home or an institutional delivery.</p> <p>Results</p> <p>The use of traditional birth attendants and home delivery were preferable for some community members despite the availability of the village midwife in the village. Physical distance and financial limitations were two major constraints that prevented community members from accessing and using trained attendants and institutional deliveries. A number of respondents reported that trained delivery attendants or an institutional delivery were only aimed at women who experienced obstetric complications. The limited availability of health care providers was reported by residents in remote areas. In these settings the village midwife, who was sometimes the only health care provider, frequently travelled out of the village. The community perceived the role of both village midwives and traditional birth attendants as essential for providing maternal and health care services.</p> <p>Conclusions</p> <p>A comprehensive strategy to increase the availability, accessibility, and affordability of delivery care services should be considered in these West Java areas. Health education strategies are required to increase community awareness about the importance of health services along with the existing financing mechanisms for the poor communities. Public health strategies involving traditional birth attendants will be beneficial particularly in remote areas where their services are highly utilized.</p
A longitudinal study of multicultural curriculum in medical education
OBJECTIVE: To evaluate impact a multicultural interclerkship had on students\u27 perception of knowledge, interview skills, and empathy towards serving culturally diverse populations and role student demographics played in learning.
METHODS: Data extracted from students\u27 self-reported course evaluations and pre/post questionnaires during multiculturalism interclerkship across 11 academic years. Inquired students\u27 opinion about four areas: effectiveness, small group leaders, usefulness, and overall experience. Subscale and item ratings were compared using trend tests including multivariate analyses.
RESULTS: During studied years, 883 students completed course evaluation with high overall mean rating of 3.08 (S = 0.45) and subscale mean scores ranging from 3.03 to 3.30. Trends in three of four subscales demonstrated clear uptrend (p \u3c 0.0001). Positive correlations between ratings of leaders and usefulness were observed (p \u3c 0.0001). Pre/post matched dataset (n = 967) indicated majority of items (19/23) had statistically significant higher post interclerkship ratings compared to pre scores with nine of 19 having statistically significant magnitudes of change. Questionnaire had high overall reliability (Cronbach alpha = 0.8), and item-to-group correlations ranged from 0.40 to 0.68 (p \u3c 0.0001).
CONCLUSIONS: By increasing students\u27 exposure and interaction with diverse patients, their knowledge, attitude, and skills were increased and expanded in positive manner. These findings might inform those who are interested in enhancing this important competence. This is especially true given increasing scrutiny this global topic is receiving within and across healthcare professions around the world
Development of a telescope for medium-energy gamma-ray astronomy
The Advanced Energetic Pair Telescope (AdEPT) is being developed at GSFC as a future NASA MIDEX mission to explore the medium-energy (5–200 MeV) gamma-ray range. The enabling technology for AdEPT is the Three- Dimensional Track Imager (3-DTI), a gaseous time projection chamber. The high spatial resolution 3-D electron tracking of 3-DTI enables AdEPT to achieve high angular resolution gamma-ray imaging via pair production and triplet production (pair production on electrons) in the medium-energy range. The low density and high spatial resolution of 3-DTI allows the electron positron track directions to be measured before they are dominated by Coulomb scattering. Further, the significant reduction of Coulomb scattering allows AdEPT to be the first medium-energy gamma-ray telescope to have high gamma-ray polarization sensitivity. We review the science goals that can be addressed with a medium-energy pair telescope, how these goals drive the telescope design, and the realization of this design with AdEPT. The AdEPT telescope for a future MIDEX mission is envisioned as a 8 m3 active volume filled with argon at 2 atm. The design and performance of the 3-DTI detectors for the AdEPT telescope are described as well as the outstanding instrument challenges that need to be met for the AdEPT mission
Wildlife Management Practices Associated with Pathogen Exposure in Non-NativeWild Pigs in Florida, U.S.
Land use influences disease emergence by changing the ecological dynamics of humans, wildlife, domestic animals, and pathogens. This is a central tenet of One Health, and one that is gaining momentum in wildlife management decision-making in the United States. Using almost 2000 serological samples collected from non-native wild pigs (Sus scrofa) throughout Florida (U.S.), we compared the prevalence and exposure risk of two directly transmitted pathogens, pseudorabies virus (PrV) and Brucella spp., to test the hypothesis that disease emergence would be positively correlated with one of the most basic wildlife management operations: Hunting. The seroprevalence of PrV-Brucella spp. coinfection or PrV alone was higher for wild pigs in land management areas that allowed hunting with dogs than in areas that culled animals using other harvest methods. This pattern did not hold for Brucella alone. The likelihood of exposure to PrV, but not Brucella spp., was also significantly higher among wild pigs at hunted sites than at sites where animals were culled. By failing to consider the impact of dog hunting on the emergence of non-native pathogens, current animal management practices have the potential to affect public health, the commercial livestock industry, and wildlife conservation
Wildlife Management Practices Associated with Pathogen Exposure in Non-NativeWild Pigs in Florida, U.S.
Land use influences disease emergence by changing the ecological dynamics of humans, wildlife, domestic animals, and pathogens. This is a central tenet of One Health, and one that is gaining momentum in wildlife management decision-making in the United States. Using almost 2000 serological samples collected from non-native wild pigs (Sus scrofa) throughout Florida (U.S.), we compared the prevalence and exposure risk of two directly transmitted pathogens, pseudorabies virus (PrV) and Brucella spp., to test the hypothesis that disease emergence would be positively correlated with one of the most basic wildlife management operations: Hunting. The seroprevalence of PrV-Brucella spp. coinfection or PrV alone was higher for wild pigs in land management areas that allowed hunting with dogs than in areas that culled animals using other harvest methods. This pattern did not hold for Brucella alone. The likelihood of exposure to PrV, but not Brucella spp., was also significantly higher among wild pigs at hunted sites than at sites where animals were culled. By failing to consider the impact of dog hunting on the emergence of non-native pathogens, current animal management practices have the potential to affect public health, the commercial livestock industry, and wildlife conservation
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