655 research outputs found
Letter from William C. Little to Leander Harris, July 30, Year Unknown
A reproduction of the original and typed transcription of letter from William C. Little to Leander Harris, dated July 30, Year Unknown [1862?]
Letter from William C. Little to Leander Harris, August 09, 1863
A reproduction of the original and typed transcription of letter from William C. Little to Leander Harris, dated August 09, 1863
Letter from William C. Little to Leander Harris, undated
A reproduction of the original and typed transcription of letter from William C. Little to Leander Harris, undated [1862?]
Letter from William C. Little to Leander Harris, September 28, 1862
A reproduction of the original and typed transcription of letter from William C. Little to Leander Harris, dated September 28, 1862
Functional Effects of Endogenous Bradykinin in Congestive Heart Failure
AbstractObjectives. The purpose of this study was to determine the level and functional effects of endogenous bradykinin in congestive heart failure (CHF).Background. There is experimental evidence that bradykinin is increased in several cardiac disease states. However, it is unknown whether plasma levels of bradykinin are elevated in CHF. Further, the cardiac and vascular responses to bradykinin in CHF are unclear.Methods. The circulating levels of bradykinin and the effects of endogenous bradykinin were assessed in eight instrumented, conscious dogs both before and after pacing-induced CHF.Results. Before CHF, the plasma bradykinin level was 53.1 ± 12.4 pg/ml. Blocking endogenous bradykinin with HOE-140 (0.3 mg/kg), a specific bradykinin B2-receptor antagonist, produced no significant alterations in heart rate, left ventricular (LV) end-systolic pressure (Pes), total systemic resistance (TSR), the time constant of LV relaxation (tau) or the maximal rate of LV filling (dV/dtmax). However, coronary blood flow was significantly reduced (p < 0.05). LV contractile performance measured by the slopes of pressure–volume relations was unaffected. After induction of CHF, the plasma bradykinin level increased to 234.2 ± 19.4 pg/ml (p < 0.05). Blocking endogenous bradykinin with HOE-140 reduced coronary blood flow and produced significant increases in Pesand TSR, prolonged tau, decreased dV/dtmaxand elevated minimal LV pressure and mean left atrial pressure. Furthermore, the slopes of pressure–volume relations (p < 0.05) were decreased, indicating depressed contractility with HOE-140 after CHF.Conclusions. Before CHF, endogenous bradykinin results in coronary dilation but has no effect on systemic arterial vasodilation or cardiac performance. After CHF, endogenous bradykinin is significantly increased and, acting through B2-receptors, produces coronary and arterial vasodilation and improves LV relaxation and contractile performance. Thus, endogenous bradykinin may play an important role in preserving cardiovascular function in CHF
Losartan improves exercise tolerance in patients with diastolic dysfunction and a hypertensive response to exercise
AbstractOBJECTIVESThe aim of the study was to test the hypothesis that angiotensin II (Ang II) blockade would improve exercise tolerance in patients with diastolic dysfunction and a marked increase in systolic blood pressure (SBP) during exercise.BACKGROUNDDiastolic dysfunction may be exacerbated during exercise, especially if there is a marked increase in SBP. Angiotensin II may contribute to the hypertensive response to exercise and impair diastolic performance.METHODSWe performed a randomized, double-blind, placebo-controlled, crossover study of two weeks of losartan (50 mg q.d.) on exercise tolerance and quality of life. The subjects were 20 patients, mean age 64 ± 10 years with normal left ventricular systolic function (EF >50%), no ischemia on stress echocardiogram, mitral flow velocity E/A <1, normal resting SBP (<150 mm Hg), and a hypertensive response to exercise (SBP >200 mm Hg). Exercise echocardiograms (Modified Bruce Protocol) and the Minnesota Living With Heart Failure questionnaire were administered at baseline, and after each two-week treatment period, separated by a two-week washout period.RESULTSResting blood pressure (BP) was unaltered by placebo or losartan. During control, patients were able to exercise for 11.3 ± 2.5 (mean ± SD) min, with a peak exercise SBP of 226 ± 24 mm Hg. After two weeks of losartan, baseline BP was unaltered, but peak SBP during exercise decreased to 193 ± 27 mm Hg (p < 0.05 vs. baseline and placebo), and exercise time increased to 12.3 ± 2.6 min (p < 0.05 vs. baseline and placebo). With placebo, there was no improvement in exercise duration (11.0 ± 2.0 min) or peak exercise SBP (217 ± 26 mm Hg). Quality of life improved with losartan (18 ± 22, p < 0.05) compared to placebo (22 ± 26).CONCLUSIONSIn patients with Doppler evidence of diastolic dysfunction at rest and a hypertensive response to exercise, Ang II receptor blockade blunts the hypertensive response to exercise, increases exercise tolerance and improves quality of life
Accurate estimates of absolute left ventricular volumes from equilibrium radionuclide angiographic count data using a simple geometric attenuation correction
To simplify and clarify the methods of obtaining attenuation-corrected equilibrium radionuclide angiographic estimates of absolute left ventricular volumes, 27 patients who also had biplane contrast cineangiography were evaluated. Background-corrected left ventricular end-diastolic and end-systolic counts were obtained by semiautomated variable and hand-drawn regions of interest and were normalized to cardiac cycles processed, frame rate and blood sample counts. Blood sample counts were acquired on (d°) and at a distance (d′) from the collimator. A simple geometric attenuation correction was performed to obtain absolute left ventricular volume estimates.Using blood sample counts obtained at d° or d′, the attentuation.corrected radionuclide left ventricular end-diastolic volume estimates using both region of interest selection methods correlated with the cineangiographic end-diastolic volumes (r = 0.95 to 0.96). However, both mean radionuclide semiautomated variable left ventricular end-diastolic volumes (179 ± 100 [± 1 standard deviation] and 185 ± 102 ml, p < 0.001) were smaller than the average cineangiographic end-diastolic volume (217 ± 102 ml), and both mean hand-drawn left ventricular end-diastolic volumes (212 ± 104 and 220 ± 106 ml) did not differ from the average cineangiographic end-diastolic volume. Using the blood sample counts obtained at d° or d′, the attenuation-corrected radionuclide left ventricular end-systolic volume estimates using both region of interest selection methods correlated with the cineangiographic end-systolic volumes (r = 0.96 to 0.98). Also, using blood sample counts at d°, the mean radionuclide semiautomated variable left ventricular end-systolic volume (116 ± 98 ml, p < 0.05) was less than the average cineangiographic end-systolic volume (128 ± 98 ml), and the other radionuclide end-systolic volumes did not differ from the average cineangiographic end-systolic volume.Therefore, it is concluded that: 1) a simple geometric attenuation-correction of radionuclide left ventricular end-diastolic and end-systolic count data provides accurate estimates of biplane cineangiographic end-diastolic and end-systolic volumes; and 2) the hand-drawn region of interest selection method, unlike the semiautomated variable method that underestimates end-diastolic and end-systolic volumes, provides more accurate estimates of biplane cineangiographic left ventricular volumes irrespective of the distance blood sample counts are acquired from the collimator
Beef production from feedstuffs conserved using new technologies to reduce negative environmental impacts
End of project reportMost (ca. 86%) Irish farms make some silage. Besides directly providing feed for livestock, the provision of grass silage within integrated grassland systems makes an important positive contribution to effective grazing management and improved forage utilisation by grazing animals, and to effective feed budgeting by farmers. It can also contribute to maintaining the content of desirable species in pastures, and to livestock not succumbing to parasites at sensitive times of the year. Furthermore, the optimal recycling of nutrients collected from housed livestock can often be best achieved by spreading the manures on the land used for producing the conserved feed. On most Irish farms, grass silage will remain the main conserved forage for feeding to livestock during winter for the foreseeable future. However, on some farms high yields of whole-crop (i.e. grain + straw) cereals such as wheat, barley and triticale, and of forage maize, will be an alternative option provided that losses during harvesting, storage and feedout are minimised and that input costs are restrained. These alternative forages have the potential to reliably support high levels of animal performance while avoiding the production of effluent. Their production and use however will need to advantageously integrate into ruminant production systems. A range of technologies can be employed for crop production and conservation, and for beef production, and the optimal options need to be identified. Beef cattle being finished indoors are offered concentrate feedstuffs at rates that range from modest inputs through to ad libitum access. Such concentrates frequently contain high levels of cereals such as barley or wheat. These cereals are generally between 14% to 18% moisture content and tend to be rolled shortly before being included in coarse rations or are more finely processed prior to pelleting. Farmers thinking of using ‘high-moisture grain’ techniques for preserving and processing cereal grains destined for feeding to beef cattle need to know how the yield, conservation efficiency and feeding value of such grains compares with grains conserved using more conventional techniques. European Union policy strongly encourages a sustainable and multifunctional agriculture. Therefore, in addition to providing European consumers with quality food produced within approved systems, agriculture must also contribute positively to the conservation of natural resources and the upkeep of the rural landscape. Plastics are widely used in agriculture and their post-use fate on farms must not harm the environment - they must be managed to support the enduring sustainability of farming systems. There is an absence of information on the efficacy of some new options for covering and sealing silage with plastic sheeting and tyres, and an absence of an inventory of the use, re-use and post-use fate of plastic film on farms. Irish cattle farmers operate a large number of beef production systems, half of which use dairy bred calves. In the current, continuously changing production and market conditions, new beef systems must be considered. A computer package is required that will allow the rapid, repeatable simulation and assessment of alternate beef production systems using appropriate, standardised procedures. There is thus a need to construct, evaluate and utilise computer models of components of beef production systems and to develop mathematical relationships to link system components into a network that would support their integration into an optimal system model. This will provide a framework to integrate physical and financial on-farm conditions with models for estimating feed supply and animal growth patterns. Cash flow and profit/loss results will be developed. This will help identify optimal systems, indicate the cause of failure of imperfect systems and identify areas where applied research data are currently lacking, or more basic research is required
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