894 research outputs found
The 63rd Symposium of the Society of General Physiologists: “muscles” instead of squid at Woods Hole
Changes in Water Quality of Grand Lake St. Marys Watershed Following Implementation of a Distressed Watershed Rules Package
Grand Lake St. Marys watershed has drawn attention over the past decade as water quality issues resulting from nutrient loading have come to the forefront of public opinion, political concern, and scientific study. The objective of this study was to assess long-term changes in water quality (nutrient and sediment concentrations) following the distressed watershed rules package instituted in 2011. Since that time, a variety of rules (e.g., winter manure ban) and best management practices (cover crops, manure storage or transfers, buffers, etc.) have been implemented. We used a general linear model to assess variation in total suspended solids, particulate phosphorus, soluble reactive phosphorus (SRP), nitrate N, and total Kjeldahl nitrogen concentrations from daily Chickasaw Creek (drains ∼25% of watershed) samples spanning 2008 to 2016. Parameters were related to flow (higher values during high flows), timing (lower values during winter months), and the implementation of the distressed watershed rules package (lower values following implementation). Overall, reductions following the distressed designation for all parameters ranged from 5 to 35% during medium and high flow periods (with exception of SRP). Reductions were even more pronounced during winter months covered by the manure ban, where all parameters (including SRP) exhibited decreases at medium and high flows between 20 and 60%. While the reductions seen in this study are significant, concentrations are still highly elevated and continue to be a problem. We are optimistic that this study will serve to inform future management in the region and elsewhere
Spontaneous Coronary Artery Dissection as Presenting Feature of Vascular Ehlers-Danlos Syndrome
A spontaneous coronary artery dissection as the sole presenting feature of vascular Ehlers-Danlos syndrome is an uncommon finding. We present a 33-year-old woman with sudden onset chest pain caused by a spontaneous coronary artery dissection. Genetic testing revealed vascular Ehlers-Danlos syndrome as the underlying cause. Specifically, we show the value of genetic testing, which in some patients may be the only way of establishing a diagnosis
Muscle Chloride Channel Dysfunction in Two Mouse Models of Myotonic Dystrophy
Muscle degeneration and myotonia are clinical hallmarks of myotonic dystrophy type 1 (DM1), a multisystemic disorder caused by a CTG repeat expansion in the 3′ untranslated region of the myotonic dystrophy protein kinase (DMPK) gene. Transgenic mice engineered to express mRNA with expanded (CUG)250 repeats (HSALR mice) exhibit prominent myotonia and altered splicing of muscle chloride channel gene (Clcn1) transcripts. We used whole-cell patch clamp recordings and nonstationary noise analysis to compare and biophysically characterize the magnitude, kinetics, voltage dependence, and single channel properties of the skeletal muscle chloride channel (ClC-1) in individual flexor digitorum brevis (FDB) muscle fibers isolated from 1–3-wk-old wild-type and HSALR mice. The results indicate that peak ClC-1 current density at −140 mV is reduced >70% (−48.5 ± 3.6 and −14.0 ± 1.6 pA/pF, respectively) and the kinetics of channel deactivation increased in FDB fibers obtained from 18–20- d-old HSALR mice. Nonstationary noise analysis revealed that the reduction in ClC-1 current density in HSALR FDB fibers results from a large reduction in ClC-1 channel density (170 ± 21 and 58 ± 11 channels/pF in control and HSALR fibers, respectively) and a modest decrease in maximal channel open probability(0.91 ± 0.01 and 0.75 ± 0.03, respectively). Qualitatively similar results were observed for ClC-1 channel activity in knockout mice for muscleblind-like 1 (Mbnl1ΔE3/ΔE3), a second murine model of DM1 that exhibits prominent myotonia and altered Clcn1 splicing (Kanadia et al., 2003). These results support a molecular mechanism for myotonia in DM1 in which a reduction in both the number of functional sarcolemmal ClC-1 and maximal channel open probability, as well as an acceleration in the kinetics of channel deactivation, results from CUG repeat–containing mRNA molecules sequestering Mbnl1 proteins required for proper CLCN1 pre-mRNA splicing and chloride channel function
Expression of parathyroid hormone-related protein during immortalization of human peripheral blood mononuclear cells by HTLV-1: Implications for transformation
<p>Abstract</p> <p>Background</p> <p>Adult T-cell leukemia/lymphoma (ATLL) is initiated by infection with human T-lymphotropic virus type-1 (HTLV-1); however, additional host factors are also required for T-cell transformation and development of ATLL. The HTLV-1 Tax protein plays an important role in the transformation of T-cells although the exact mechanisms remain unclear. Parathyroid hormone-related protein (PTHrP) plays an important role in the pathogenesis of humoral hypercalcemia of malignancy (HHM) that occurs in the majority of ATLL patients. However, PTHrP is also up-regulated in HTLV-1-carriers and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients without hypercalcemia, indicating that PTHrP is expressed before transformation of T-cells. The expression of PTHrP and the PTH/PTHrP receptor during immortalization or transformation of lymphocytes by HTLV-1 has not been investigated.</p> <p>Results</p> <p>We report that PTHrP was up-regulated during immortalization of lymphocytes from peripheral blood mononuclear cells by HTLV-1 infection in long-term co-culture assays. There was preferential utilization of the PTHrP-P2 promoter in the immortalized cells compared to the HTLV-1-transformed MT-2 cells. PTHrP expression did not correlate temporally with expression of HTLV-1 tax. HTLV-1 infection up-regulated the PTHrP receptor (PTH1R) in lymphocytes indicating a potential autocrine role for PTHrP. Furthermore, co-transfection of HTLV-1 expression plasmids and PTHrP P2/P3-promoter luciferase reporter plasmids demonstrated that HTLV-1 up-regulated PTHrP expression only mildly, indicating that other cellular factors and/or events are required for the very high PTHrP expression observed in ATLL cells. We also report that macrophage inflammatory protein-1α (MIP-1α), a cellular gene known to play an important role in the pathogenesis of HHM in ATLL patients, was highly expressed during early HTLV-1 infection indicating that, unlike PTHrP, its expression was enhanced due to activation of lymphocytes by HTLV-1 infection.</p> <p>Conclusion</p> <p>These data demonstrate that PTHrP and its receptor are up-regulated specifically during immortalization of T-lymphocytes by HTLV-1 infection and may facilitate the transformation process.</p
Elderly Subjects Have a Delayed Antibody Response and Prolonged Viraemia following Yellow Fever Vaccination: A Prospective Controlled Cohort Study
Yellow fever vaccination (YF-17D) can cause serious adverse events (SAEs). The mechanism of these SAEs is poorly understood. Older age has been identified as a risk factor. We tested the hypothesis that the humoral immune response to yellow fever vaccine develops more slowly in elderly than in younger subjects.We vaccinated young volunteers (18–28 yrs, N = 30) and elderly travelers (60–81 yrs, N = 28) with YF-17D and measured their neutralizing antibody titers and plasma YF-17D RNA copy numbers before vaccination and 3, 5, 10, 14 and 28 days after vaccination. = 0.02, using a mixed linear model. Viraemia was more common in the elderly (86%, 24/28) than in the younger participants (60%, 14/30) (p = 0.03) with higher YF-17D RNA copy numbers in the elderly participants.We found that elderly subjects had a delayed antibody response and higher viraemia levels after yellow fever primovaccination. We postulate that with older age, a weaker immune response to yellow fever vaccine allows the attenuated virus to cause higher viraemia levels which may increase the risk of developing SAEs. This may be one piece in the puzzle of the pathophysiology of YEL-AVD
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