Low levels of frailty in HIV-positive older adults on antiretroviral therapy in northern Tanzania

Journal of NeuroVirology - There are over 3 million people in sub-Saharan Africa (SSA) aged 50 and over living with HIV. HIV and combined antiretroviral therapy (cART) exposure may accelerate the...     

Relation of lactate production to postischaemic reduction in function and myocardial oxygen consumption after partial coronary occlusion in swine

Postischaemic myocardial dysfunction (stunning) induced by partial occlusion of the left anterior descending coronary artery and its relation to lactate production during reperfusion were studied in nine swine. A 40% reduction in regional left ventricular wall thickening, as measured by ultrasonic crystals, was prospectively defined as stunning. A perfusion pressure of 20 mmHg was maintained with a hydraulic occluder for each ischaemic period and was monitored by a distal arterial catheter. To achieve a 40% reduction in function, four animals required three ischaemic periods (mean ischaemic flow reduction 73%), four two (86% flow reduction), and one one (93% flow reduction). At 25 min of reperfusion transmural flow was slightly reduced from 0.67 ml.g-1.min-1 at control to 0.58 ml.g-1.min-1 (p less than 0.05), whereas regional flow endocardial to epicardial flow ratio was unchanged. At 60 min reperfusion, percentage systolic wall thickening was reduced to 25% from a control of 39% (p less than 0.01) and parallel reductions in regional myocardial oxygen consumption from 4.3 ml.min-1 to 2.7 ml.min-1 occurred (p less than 0.01). Lactate extraction was depressed at 15 min reperfusion (-4.0% compared with control +18.0% (p less than 0.05)) but returned to control values by 30 min. It is concluded that postischaemic myocardial dysfunction (stunning) can be induced by partial coronary occlusions and that the extent of dysfunction depends on the degree of flow reduction. The reductions in myocardial oxygen consumption parallel those of wall thickening during reperfusion after stunning. Finally, lactate production occurs during early reperfusion but does not persist with the postischaemic reductions in function and myocardial oxygen consumption.     

A quantitative study of the anatomy and distribution of coronary arteries in swine in comparison with other animals and man

The coronary circulation of swine was studied to establish adequate baseline information for using swine in cardiovascular research. Of 65 hearts from domestic and miniature pigs, 45 were injected with a methacrylate plastic and prepared as coronary artery casts whose branches were described and measured, and 20 were injected with different coloured dyes in the right, left anterior descending, and circumflex coronary arteries so that horizontal sections of the heart showed the distribution of each artery and the source of blood supply to particular areas or structures of the heart. Like man, the swine had a left coronary artery that was larger in diameter and longer than the right coronary artery. The right coronary artery was almost always dominant (78%), supplying the posterior septum and atrioventricular node via the posterior descending coronary artery. Eight (17%) of the hearts possessed a balanced blood supply. Two (5%) hearts had a left dominant supply. The intracoronary artery dye injections showed that 72.4% of the right ventricular mass was supplied by the right coronary artery and 27.6% by the left anterior descending coronary artery. In the left ventricle 49% of the mass was supplied by the left anterior descending coronary artery, 25.5% by the right coronary artery, and 25.5% by the circumflex coronary artery. The left anterior descending coronary artery supplied 58% of the interventricular septal mass, while the posterior descending coronary artery supplied 42%. The distribution of the left anterior descending coronary artery branches to the ventricular wall varied inversely in number and size of its diagonal branches (2-9) with the obtuse marginal branches of the circumflex coronary artery which were occasionally more numerous or extended to the apex. The blood supply to the sinoatrial node was always by a branch of the right coronary artery. This analysis shows that not only the coronary anatomy but also the distribution of blood supply to particular areas or structures of the swine heart are very similar to that of humans.     

The relative importance of thrombin inhibition and factor Xa inhibition to the antithrombotic effects of heparin

The relative importance of antithrombin and anti-factor Xa activities of heparin fractions required to achieve optimal antithrombotic effects is unknown. To study this, we measured the effects of standard heparin, an octasaccharide heparin fraction (anti-factor Xa activity only), and dermatan sulfate (antithrombin activity only) on the prevention of thrombosis and related this to their anticoagulant effects in vivo in rabbits. Thrombosis was measured as the incorporation of 125I- fibrinogen into tissue thromboplastin-induced thrombi using a Wessler- type model. Ex vivo changes in thrombin clotting time (TCT) were used as an index of antithrombin activity, and a chromogenic anti-factor Xa assay was used to measure anti-factor Xa activity. In addition, the ability of the three sulfated polysaccharides to simultaneously inhibit the generation of thrombin activity and to enhance the inactivation of the factor Xa added to initiate thrombin generation in plasma was determined. Standard heparin, in a dose of 10 anti-factor Xa U/kg, inhibited thrombus formation by 90%, prolonged the TCT by two seconds, and resulted in an anti-factor Xa level of 0.32 U/mL. The octasaccharide heparin fraction, in a dose of 10 anti-factor Xa U/kg, inhibited thrombus formation by 41%, had no effect on the TCT, and resulted in an anti-factor Xa level of 0.28 U/mL. Higher doses of the octasaccharide resulted in a further increase in the anti-factor Xa levels but had no further effect on thrombus formation. Dermatan sulfate, in a dose of 500 micrograms/kg, inhibited thrombus formation by 95%, but had no affect on the TCT. These results indicate that the antithrombotic effect achieved by inhibiting factor Xa is limited and that better antithrombotic effects are achieved by heparin or heparin- like substances capable of influencing the inactivation and/or the generation of thrombin.     

Leishmania infantum DNA detection in Phlebotomus tobbi in a new northern focus of visceral leishmaniasis in Iran

Objective

To identify the vector(s), the parasite and the species composition of sand flies in the district during May-October 2012.

Methods

For reaching our objectives we used polymerase chain reaction of kDNA, ITS1-rDNA, followed by restriction fragment length polymorphism.

Results

Two species of Phlebotomus sergenti and Phlebotomus tobbi were the most prevalent among 8 species identified comprising 51.1% and 32.9% respectively. Among the 160 specimens of female sand flies tested by polymerase chain reaction of kDNA, ITS1-rDNA, followed by restriction fragment length polymorphisms, only 1 out of 80 Phlebotomus tobbi (1.25%) were positive to Leishmania infantum parasites.

Conclusions

Our finding showed that Phlebotomus tobbi may play as a vector to circulate the parasite of Leishmania infantum among reservoir(s) and human.