The pulmonary arterial pressure of Ladakhi yaks, at an altitude of about 4500m, was not significantly different from that found in yaks bred at low altitude. The pulmonary arterial resistance, however, was slightly but significantly increased in the high altitude group. It is concluded that the yak has adapted genetically to high altitude by largely eliminating the hypoxic pulmonary vasoconstri...

Tumour necrosis factor (TNF) is a ubiquitously expressed cytokine with functions beyond the immune system. In several diseases, the induction of TNF expression in resistance artery smooth muscle cells enhances microvascular myogenic vasoconstriction and perturbs blood flow. This pathological role prompted our hypothesis that constitutively expressed TNF regulates myogenic signalling and systemi...

Controversy exists regarding the timing and technique of total correction of traumatic intracardiac lesions. Five patients with penetrating wounds of the heart received emergency treatment aimed at securing normal haemodynamics. No attempt was made to identify intracardiac lesions at this stage. Cineangiography two months to seven years later showed aorto-right ventricular fistulae in all patie...

1. Systemic haemodynamics and kidney function were studied in the same dogs before and 14 days after choledochocaval anastomosis. 2. All dogs became deeply jaundiced whereas parenchymal liver function remained unchanged as assessed biochemically. 3. After choledochocaval anastomosis there was a decrease in mean arterial pressure (118 +/- 18 to 98 +/- 13 mmHg, P less than 0.005), and total perip...

We have studied the cerebral haemodynamic and metabolic effects of fentanyl 50 micrograms kg-1 and 100 micrograms kg-1 in dogs undergoing ventilation with oxygen and nitrogen at normocapnia. Cerebral blood flow was measured continuously by direct measurement of the outflow of the posterior sagittal sinus. Arterial and sagittal sinus blood-gas tensions were measured intermittently for calculatio...

Physiologic functioning of the cerebrovenous system is indispensable for maintaining normal brain function. However, in contrast to the cerebroarterial system, the cerebral venous return is not routinely investigated. Combined high-resolution echo-colour-Doppler (ECD) and transcranial colour coded Doppler sonography (TCCS) represents an ideal method to investigate the haemodynamics of cerebral ...

Coronary artery hemodynamics are very different to that of the systemic arteries; unlike the systemic circulation, in the coronary circulation pressure is generated from both the proximal and distal end of the artery - due to the effect of contraction and relaxation of the myocardium on the microvasculature. As a result, the systemic artery hemodynamic model cannot be used to explain the pressu...