Chronic rapid ventricular pacing in the dog reportedly produces a useful preparation of low-output heart failure. However, little information is available regarding cardiac changes in this preparation. Accordingly, we evaluated the effects of both short-term (3 weeks) and prolonged (2 months) rapid ventricular pacing on cardiac hemodynamics, mass, and chamber size. The effects of short-term pacing on left ventricular wall thickening, blood flow, and metabolism were also examined. Compared with 16 control dogs, dogs paced for either 3 weeks (n = 8) or 2 months (n = 13) exhibited reduced cardiac outputs (control 130 20 ml/min/kg, 3 week pacing 112 19 ml/min/kg, 2 month pacing 116 14 ml/min/kg) and elevated pulmonary wedge pressures (control 10 3 mm Hg, 3 week pacing 26 5 mm Hg, 2 month pacing 26 + 8 mm Hg) and right atrial pressures (control 4 1 mm Hg, 3 week pacing 13 + 3 mm Hg, 2 month pacing 9 + 3 mm Hg) (all p < .01 vs control). At the postmortem examination, both groups of paced dogs also exhibited increased left ventricular volumes (control 13 ± 6 ml, 3 week pacing 27 + 6 ml, 2 month pacing 26 ± 8 ml), right ventricular volumes (control 13 ± 5 ml, 3 week pacing 27 + 9, 2 month pacing 24 ± 7 ml), and right ventricular mass (control 27 + 5 g, 3 week pacing 32 ± 6 g, 2 month pacing 34 ± 6 g) (all p < .03 vs control) but had normal left ventricular mass. Three weeks of pacing also decreased percent left ventricular shortening (34 ± 6% to 17 ± 7%) associated with a disproportionate deterioration of posterior wall thickening (58 + 16% to 17 ± 18%) (both p < .01), as assessed by echocardiography. This left ventricular dysfunction was associated with no change in myocardial lactate extraction (prepacing 40 10%, 3 week pacing 36 ± 10%), myocardial arteriovenous 02 difference, or myocardial histology, suggesting that it was not due to myocardial ischemia. These data indicate that rapid ventricular pacing in the dog produces a useful experimental preparation of low-output heart failure characterized by biventricular pump dysfunction, biventricular cardiac dilation, and nonischemic impairment of left ventricular contractility. Circulation 75, No. 4, 857-867, 1987. A VARIETY of canine experimental preparations of congestive heart failure have been developed.' However, most of these preparations have major limitations. Those based on volume and pressure overloading are technically complicated since it is difficult to control the degree of overloading, and those based on production of venous obstruction and/or right heart failure may not resemble heart failure in man, which
BackgroundThe seroprevalence and risk factors of bovine brucellosis were studied at animal and herd level using a combination of culture, serological and molecular methods. The study was conducted in 253 randomly selected cattle herds of the Potohar plateau, Pakistan from which a total of 2709 serum (1462 cattle and 1247 buffaloes) and 2330 milk (1168 cattle and 1162 buffaloes) samples were collected. Data on risk factors associated with seroprevalence of brucellosis were collected through interviews using questionnaires. Univariable and multivariable random effects logistic regression models were used for identifying important risk factors at animal and herd levels.ResultsOne hundred and seventy (6.3%) samples and 47 (18.6%) herds were seropositive for brucellosis by Rose Bengal Plate test. Variations in seroprevalence were observed across the different sampling sites. At animal level, sex, species and stock replacement were found to be potential risk factors for brucellosis. At herd level, herd size (≥9 animals) and insemination method used were important risk factors. The presence of Brucella DNA was confirmed with a real-time polymerase chain reaction assay (qRT-PCR) in 52.4% out of 170 serological positive samples. In total, 156 (6.7%) milk samples were positive by milk ring test. B. abortus biovar 1 was cultured from 5 positive milk samples.ConclusionThis study shows that the seroprevalence of bovine brucellosis is high in some regions in Pakistan. Prevalence was associated with herd size, abortion history, insemination methods used, age, sex and stock replacement methods. The infected animal may act as source of infection for other animals and for humans. The development of control strategies for bovine brucellosis through implementation of continuous surveillance and education programs in Pakistan is warranted.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-017-2394-2) contains supplementary material, which is available to authorized users.
M-mode echocardiographic measurement of left ventricular fractional shortening and meridional wall stress has been used extensively alone and in combination to describe left ventricular systolic function. To determine whether the improved dimensional information afforded by two-dimensional echocardiography might result in shortening and stress calculations yielding a different view of left ventricular function, we compared two-dimensional and M-mode echocardiograms in 69 subjects (19 normal, 13 with aortic stenosis, 22 with aortic regurgitation and 15 with congestive cardiomyopathy). Fractional shortening was greater with M-mode than with two-dimensional echocardiography in all subjects, especially in those with cardiomyopathy (p less than 0.05). In aortic stenosis, two-dimensional shortening, at 24 +/- 5%, was reduced (p less than 0.05 versus normal), but M-mode shortening, at 34 +/- 5%, was not. M-mode estimates of meridional stress were higher than two-dimensional values, again especially in cardiomyopathy. Two-dimensional echocardiography enabled determination of long- and short-axis ratios, circumferential stress and the ratio of circumferential to meridional stresses. Circumferential stress was elevated in aortic stenosis at 302 +/- 65 X 10(3) dynes/cm2, suggesting afterload excess as the cause for the observed reduction in two-dimensional shortening. The more spherical cardiomyopathic hearts had a meridional to circumferential stress ratio closer to 1, such that use of meridional stress alone would overestimate effective afterload. It is concluded that M-mode and two-dimensional echocardiographic analyses of left ventricular shortening and stress produce different results. Two-dimensional echocardiographic methods may enhance the assessment of ventricular function, especially in patients with aortic stenosis and cardiomyopathy.
An experiment was conducted at the Department of Animal Science teaching and research farm, Bayero University Kano, to evaluate the effect of feeding graded levels of Moringa oleifera leaf meal (MOLM) in diets on growth performance, carcass and organ characteristics of weaned rabbits. Twenty eight grower rabbits of averagely 975g in weight were allotted into four treatments of seven rabbits each in a completely randomize design. Four isonitrogenous diets (16% CP) were formulated in which MOLM was included at 0, 15, 30 and 45% for treatments 1, 2, 3 and 4 respectively. The diets were fed to the animals for eight weeks. The result showed that daily weight gain (5.95-13.39g/day) and carcass weight (497.70-727.65g) increased (P<0.05) with increasing levels of MOLM in diets, but dressing percentage (42.49-45.96%) was not affected by dietary treatments. Similarly, the weight of liver (40.35-57.05g), lungs (10.22-11.24g), heart (2.95-4.10g), kidney (8.30-10.70g), kidney fat (11.10-12.65g), small intestine (81.25-99.80g), large intestine (102.45-117.95g), caecum (20.50-30.50g), stomach (90.75-114.65g), spleen (1.00-1.80g) and abdominal fat (7.89-11.25g) characteristics were not different across the treatments. The results indicate that weaned rabbits can utilize Moringa oleifera leaf meal at up to 45% level of inclusion in diets without any deleterious effects on growth performance, carcass yield and organ characteristics.
Type 1 diabetes mellitus (DM) is a strong risk factor for the development of diabetic cardiomyopathy (DCM) which is the leading cause of morbidity and mortality in the type 1 diabetic patients. Stem cells may act as a therapeutic agent for the repair of DCM. However, deteriorated functional abilities and survival of stem cells derived from type 1 diabetic subjects need to be overcome for obtaining potential outcome of the stem cell therapy. Diazoxide (DZ) a highly selective mitochondrial ATP-sensitive K(+) channel opener has been previously shown to improve the ability of mesenchymal stem cells for the repair of heart failure. In the present study, we evaluated the effects of DZ preconditioning in improving the ability of streptozotocin-induced type 1 diabetes affected bone marrow-derived endothelial progenitor cells (DM-EPCs) for the repair of DCM in the type 1 diabetic rats. DM-EPCs were characterized by immunocytochemistry, flow cytometry, and reverse transcriptase PCR for endothelial cell-specific markers like vWF, VE cadherin, VEGFR2, PECAM, CD34, and eNOS. In vitro studies included preconditioning of DM-EPCs with 200 μM DZ for 30 min followed by exposure to either 200 μM H2O2 for 2 h (for oxidative stress induction) or 30 mM glucose media (for induction of hyperglycemic stress) for 48 h. Non-preconditioned EPCs with and without exposure to H2O2 and 30 mM high glucose served as controls. These cells were then evaluated for survival (by MTT and XTT cell viability assays), senescence, paracrine potential (by ELISA for VEGF), and alteration in gene expression [VEGF, stromal derived factor-1α (SDF-1α), HGF, bFGF, Bcl2, and Caspase-3]. DZ preconditioned DM-EPCs demonstrated significantly increased survival and VEGF release while reduced cell injury and senescence. Furthermore, DZ preconditioned DM-EPCs exhibited up-regulated expression of prosurvival genes (VEGF, SDF-1α, HGF, bFGF, and Bcl2) on exposure to H2O2, and VEGF and Bcl2 on exposure to hyperglycemia while down regulation of Caspase-3 gene. Eight weeks after type 1 diabetes induction, DZ preconditioned, and non-preconditioned DM-EPCs were transplanted into left ventricle of diabetic rats (at a dose of 2 × 10(6) DM-EPCs/70 μl serum free medium). After 4 weeks, DZ preconditioned DM-EPCs transplantation improved cardiac function as assessed by Millar's apparatus. There was decrease in collagen content estimated by Masson's trichrome and sirius red staining. Furthermore, reduced cell injury was observed as evidenced by decreased expression of Caspase-3 and increased expression of prosurvival genes Bcl2, VEGF, and bFGF by semi-quantitative real-time PCR. In conclusion, the present study demonstrated that DZ preconditioning enhanced EPCs survival under oxidative and hyperglycemic stress and their ability to treat DCM.
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