Effect of static load on matrix synthesis rates in the intervertebral disc measured in vitro by a new perfusion technique.

The effect of static loading on matrix synthesis was measured in intact bovine coccygeal discs. The discs were maintained at 37 degrees C in a humid atmosphere and were perfused across their upper and lower surfaces for as long as 8 hours with media containing radioisotopes (3H-proline and 35S-sulphate) via porous filter disks embedded in Perspex (Plexiglas) holders. Static loads were applied to the disc with use of weights.

The effect of tolbutamide on cerebral blood flow during hypoxia and hypercapnia in the anaesthetized rat.

The increase in blood flow in the cerebral cortex of the anaesthetized rat during hypoxia and hypercapnia was investigated. Cerebral blood flow (CBF) was measured using the hydrogen clearance method with acutely implanted platinum electrodes. Hypoxia (PaO2 35.

Effect of potassium on ventilation in the rhesus monkey.

Increasing the concentration of arterial plasma K+ to 6-8 mM increased ventilation in two sedated analgesic-treated rhesus monkeys who had their end-tidal CO2 held constant during euoxia (arterial oxygen pressure, Pa,O2, ca 100 Torr) and hypoxia (Pa,O2, ca 40 Torr). During euoxia and hypoxia, hyperkalaemia increased ventilation up to 40 and 250%, respectively. This effect was reduced in euoxia and virtually abolished in hypoxia following an abrupt switch to 100% oxygen.

Distensibility of single capillaries and venules in the rat and frog mesentery.

The distensibility characteristics of single microvessels in the mesentery of frogs and rats has been determined by a new technique capable of resolving a change in radius of about 0.01 micron in vivo. Two water insoluble immiscible oils were micro-injected into occluded segments of the vessels.