2,163 research outputs found
Pvt. Tom L. Workman
No full textPrivate Tom L. Workman, son of Mr. and Mrs. Kenneth R. Workman, completed Infantry Training School at the Marine Corps Basi, in Camp Pendleton, California
Altered excitation-contraction coupling in human chronic atrial fibrillation
No full textThis review focuses on the (mal)adaptive processes in atrial excitation-contraction coupling occurring in patients with chronic atrial fibrillation. Cellular remodeling includes shortening of the atrial action potential duration and effective refractory period, depressed intracellular Ca<sup>2+</sup> transient, and reduced myocyte contractility. Here we summarize the current knowledge of the ionic bases underlying these changes. Understanding the molecular mechanisms of excitation-contraction-coupling remodeling in the fibrillating human atria is important to identify new potential targets for AF therapy
Do K<sub>ATP</sub> channels open as a prominent and early feature during ischaemia in the Langendorff-perfused rat heart?
No full textThe objective was to investigate whether myocardial adenosine triphosphate-sensitive K<sup>+</sup> (K<sub>ATP</sub>) channels open during the first 10 min of regional ischaemia in Langendorff-perfused rat hearts. Changes in monophasic action potentials and arrhythmias were studied during myocardial ischaemia in both the presence and absence of pharmacological K<sub>ATP</sub> modulation. Ligation of the left main coronary artery for 10 min did not shorten the action potential duration (APD). The APD<sub>50</sub> and APD<sub>80</sub> (15.5 +/- 1.0 and 38.1 +/- 2.3 ms, respectively [mean +/- S.E., n = 15 hearts], immediately prior to ligation) increased transiently during the first 4 min of ligation (by 160 and 79% respectively, P < 0.05), before returning to pre-ligation values, but without a significant below-baseline-shortening. The cardiac electrogram showed no accompanying ventricular tachyarrhythmia (VT). These results raised the possibility that the myocardial K<sub>ATP</sub> channels had not opened during the ligation. The K<sub>ATP</sub> opener Ro 31-6930 (0.5 and 5 microM) shortened the APD50 and APD80 during coronary ligation, to significantly below both their control and pre-occlusion values (P < 0.05), and caused a concentration-dependent increase in both the incidence and duration of VT during the ligation. Ro 31-6930 at 5 microM also shortened APD50 and APD80 even before ligation (by 50 and 62% respectively, P < 0.05), and abolished the normal APD-lengthening seen during ischaemia. The K<sub>ATP</sub> blocker glibenclamide (1 μM) abolished both the APD-shortening and pro-arrhythmic effects of the K<sub>ATP</sub> opener, both before and during coronary ligation, yet when delivered on its own, at the same concentration which abolished the effects of K<sub>ATP</sub> activation, it had no significant effect on the APD changes seen during the coronary ligation alone. These results suggest that, in Langendorff-perfused rat hearts in the absence of drugs, K<sub>ATP</sub> channels do not open during early myocardial ischaemia
Electrophysiological and arrhythmogenic effects of 5-hydroxytryptamine on human atrial cells are reduced in atrial fibrillation
No full text5-Hydroxytryptamine (5-HT) is proarrhythmic in atrial cells from patients in sinus rhythm (SR) via activation of 5-HT<sub>4</sub> receptors, but its effects in atrial cells from patients with atrial fibrillation (AF) are unknown. The whole-cell perforated patch-clamp technique was used to record L-type Ca<sup>2+</sup> current (<i>I</i><sub>CaL</sub>), action potential duration (APD) and arrhythmic activity at 37 °C in enzymatically isolated atrial cells obtained from patients undergoing cardiac surgery, in SR or with chronic AF. In the AF group, 5-HT (10 μM) produced an increase in <i>I</i><sub>CaL</sub> of 115 ± 21% above control (<i>n</i> = 10 cells, 6 patients) that was significantly smaller than that in the SR group (232 ± 33%; <i>p</i> 0.05; <i>n</i> = 27 cells, 12 patients). Subsequent co-application of isoproterenol (1 μM) caused a further increase in <i>I</i><sub>CaL</sub> in the AF group (by 256 ± 94%) that was greater than that in the SR group (22 ± 6%; p < 0.05). The APD at 50% repolarisation (APD<sub>50</sub>) was prolonged by 14 ± 3 ms by 5-HT in the AF group (<i>n</i> = 37 cells, 14 patients). This was less than that in the SR group (27 ± 4 ms; <i>p</i> < 0.05; <i>n</i> = 58 cells, 24 patients). Arrhythmic activity in response to 5-HT was observed in 22% of cells in the SR group, but none was observed in the AF group (p < 0.05). Atrial fibrillation was associated with reduced effects of 5-HT, but not of isoproterenol, on <i>I</i><sub>CaL</sub> in human atrial cells. This reduced effect on <i>I</i><sub>CaL</sub> was associated with a reduced APD<sub>50</sub> and arrhythmic activity with 5-HT. Thus, the potentially arrhythmogenic influence of 5-HT may be suppressed in AF-remodelled human atrium
Atrial cellular electrophysiological changes in patients with ventricular dysfunction may predispose to AF
No full text<b>Background:</b>
Left ventricular systolic dysfunction (LVSD) is a risk factor for atrial fibrillation (AF), but the atrial cellular electrophysiological mechanisms in humans are unclear.
Objective
This study sought to investigate whether LVSD in patients who are in sinus rhythm (SR) is associated with atrial cellular electrophysiological changes that could predispose to AF.
<b>Methods:</b>
Right atrial myocytes were obtained from 214 consenting patients in SR who were undergoing cardiac surgery. Action potentials or ion currents were measured using the whole-cell-patch clamp technique.
<b>Results:</b>
The presence of moderate or severe LVSD was associated with a shortened atrial cellular effective refractory period (ERP) (209 ± 8 ms; 52 cells, 18 patients vs 233 ± 7 ms; 134 cells, 49 patients; P <0.05); confirmed by multiple linear regression analysis. The left ventricular ejection fraction (LVEF) was markedly lower in patients with moderate or severe LVSD (36% ± 4%, n = 15) than in those without LVSD (62% ± 2%, n = 31; P <0.05). In cells from patients with LVEF ≤ 45%, the ERP and action potential duration at 90% repolarization were shorter than in those from patients with LVEF > 45%, by 24% and 18%, respectively. The LVEF and ERP were positively correlated (r = 0.65, P <0.05). The L-type calcium ion current, inward rectifier potassium ion current, and sustained outward ion current were unaffected by LVSD. The transient outward potassium ion current was decreased by 34%, with a positive shift in its activation voltage, and no change in its decay kinetics.
<b>Conclusion:</b>
LVSD in patients in SR is independently associated with a shortening of the atrial cellular ERP, which may be expected to contribute to a predisposition to AF
You Buy Goods Here, But Don'T Realize It
No full textPhotograph used for a story in the Oklahoma Times newspaper. Caption: "Sears was founded on advertising. L-r, Earl G. Workman, advertising manager; Maxine Erdwurm and Lillie Splitt.
Men with Fire Truck
No full textA group of men with fire truck, during the firemens association convention. L to R Coke Jefferies, Floyde Workman, Clyde Wilkins, Duane Paulson, Mel Burke
End-point Estimates and Multi-parameter Paraproducts on Higher Dimensional Tori
No full textAnalogues of multi-parameter multiplier operators on R^d are defined on the torus T^d. It is shown that these operators satisfy the classical Coifman-Meyer theorem. In addition, L log L and L (log L)^n end-point estimates are proved.NSF and Department of Defens
Identification of environmental sources of lead exposure in Nunavut (Canada) using stable isotope analyses
No full textBackground: Blood lead levels (BLLs) were measured in the adult Inuit population of Nunavut, Northern Canada, during the Inuit Health Survey (IHS) in 2007–2008. Approximately 10% of the adult participants had BLL over the Health Canada's guidance of 100 μg/L.
Objectives: 1) To repeat themeasurement of BLL among the IHS participants with high BLL and household members including pregnant women and children under 10 years of age; 2) to measure lead (Pb) concentrations in environmental samples to identify potential sources and 3) to explore howPb from environmental samples contributes to BLL using Pb stable isotopic analyses.
Methods: Blood samples were collected from 100 adults and 56 children in 2012. A total of 169 environmental samples (tap water, house dust, paint, country food, soil, and ammunition) were collected from 14 houses from three communities where the IHS participants had the highest BLL. Total Pb concentrations and Pb isotope mass balance were determined by inductively coupled plasma-mass spectrometry (ICP-MS).
Results: The geometric mean of BLLwas 43.1 μg/L; BLL increasedwith age andwas higher in adults than children (71.1 vs. 17.5 μg/L). Median Pb concentrations in water (1.9 μg/L) and dust (27.1 μg/m2 for wiped dust, 32.6 mg/kg for vacuumdust coarse fraction, and 141.9 mg/kg for vacuum dust fine fraction) were generally higher than in other parts of Canada. Median Pb concentrations of food and soil coarse and fine fractions were low (36.6 μg/kg, 5.4 mg/kg and 11.8 mg/kg respectively); paint chips exceeded the Canadian guidelines in two houses (median: 3.8 mg/kg). Discriminant analyses and isotope ratio analyses showed that ammunition and house dust are major sources of Pb in this study population.
Conclusion: Analyses of Pb stable isotopes are useful to identify the routes of exposure to Pb. This approach can contribute to develop targeted public health programmes to prevent Pb exposure
Ashley Ward Primary Teachers
No full textAshley Ward Primary Teachers: Front row (l to r): Glade Anderson, Dorothy Anderson, Ruth Winn, unidentified, unidentified, and Norlene Batty. Back row (l to r): Sharon Workman, unidentified, Betty Jo Hall, Edna Barney, Rhonda Ross, Susan Thacker, Nellie Kloeppel, Karen Winn, Leslie Holt, Ellen (Batty) Lemon, Ruth Sowards, and Barbara Haslem
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