Intravital, long-term follow-up of autologous experimental bone grafts.

Using a vital microscopic method, it has been possible to follow the vascular changes and bone remodelling in the same bone graft from the time of transplantation till one year afterwards. Grafts which received their first vessel early (5-9 days after grafting) contained vital bone and a vivid blood circulation one year after transplantation. Grafts which received their first vessel late (17-29 days after grafting) were only partly revascularized after one year and contained islands of dead bone.

Phosphoenolpyruvate-dependent glucose phosphotransferase activity in Streptococcus mitis ATCC 903.

A constitutive phosphoenolpyruvate (PEP)-dependent glucose phosphotransferase system was found in decryptified cells of Strep. mitis. The system displayed saturation kinetics and the apparent Km value for the non-fermentable analogue 2-deoxyglucose (2DG) was 0.

Regulation of synthesis of beta-fructofuranosidase (invertase) in Streptococcus mitis.

beta-Fructofuranosidase activity was found to be cell-bound in Streptococcus mitis ATCC 903. The following evidence suggests that induction functions as a regulatory mechanism for beta-fructofuranosidase in S. mitis: (1) on transfer of glucose-grown exponential phase bacteria to sucrose medium, the specific activity of beta-fructofuranosidase increased fourfold in the course of one generation; (2) other sugars had no stimulatory effect on the rate of synthesis of beta-fructofuranosidase; (3) the effect of sucrose on the rate of synthesis of beta-fructofuranosidase could be measured within a few minutes.

Displacement of catheters inserted through internal jugular veins with neck flexion and extension. A preliminary study.

Displacement of central venous catheters inserted through internal jugular veins in adult man was estimated on chest x-rays in six patients and measured in six corpses. The downward displacement of the catheter tips with maximum neck flexion varied between 1.0 and 2.

The blood brain barrier in renal hypertensive rats.

Spontaneous hypertensive rats (SHR) are less prone to develop a dysfunction of the blood-brain barrier (BBB) when exposed to an abrupt increase in blood pressure than normotensive rats (NR), probably as a result of vessel wall hypertrophy and increased vessel wall to lumen ratio. Hemodynamic studies have indicated that structural adaptation develops early as a response to the increased pressure load in renal hypertensive rats (RHR). In the present study RHR (one renal artery constricted and the contralateral kidney intact) were subjected to acute hypertension induced by bicuculline, a drug that induces an abrupt increase in blood pressure concomitant with pronounced cerebral vasodilatation.

Do nitrous oxide and lidocaine modify the blood-brain barrier in acute hypertension in the rat?

Acute hypertension was induced by adrenaline or bicuculline in rats mechanically ventilated with 70% nitrous oxide in oxygen, in unrestrained rats breathing the same gas mixture, and in conscious unrestrained rats breathing air. The unrestrained rats had permanent indwelling catheters in the aorta and in one jugular vein. Three minutes after the pressure rise the rats were killed and the brains perfused in situ with saline.

Hypertension-induced protein leakage in the brain in ethanol-intoxicated conscious and anesthetized rats.

Ethanol has been shown to aggravate the blood-brain barrier (BBB) dysfunction in cerebral trauma and in cerebral gas embolism, possibly by changing the endothelial cell membrane. No difference in protein extravasation was found between intoxicated and control rats under nitrous oxide anesthesia after the injection of bicuculline, a drug that hemodynamically gives rise to high blood pressure in combination with cerebral vasodilatation. In contrast there was a statistically significant increase in protein leakage in conscious intoxicated rats.

Isoelectric focusing studies on the beta-fructofuranosidases and alpha-glucosidases of Streptococcus mitis.

Extracts of Streptococcus mitis ATCC 903 were analysed for beta-fructofuranosidase and alpha-glucosidase activities by isoelectric focusing in thin-layer polyacrylamide gels combined with zymogram procedures. Three bands of activity were visualized in the gels after incubation with sucrose (pI 4.05, 4.

Reversibility of the blood-brain barrier dysfunction induced by acute hypertension.

An acute hypertensive episode of short duration (less than 3 min) induced by i.v. injection of angiotensin in rats resulted in a blood-brain barrier dysfunction that was rapidly reversible.

Cerebrovascular permeability to protein in the rat during nitrous oxide anaesthesia at various blood pressure levels.

Rats anaesthetized with 70% nitrous oxide in oxygen have a high mean arterial pressure (MAP), usually in the range of 130-155 mmHg. It occasionally reaches higher levels, and when MAP exceeds 160 mmHg the cerebrovascular permeability may increase. In the present study all rats with MAP greater than 170 mmHg showed areas of protein leakage in the brain.

Cerebrovascular permeability in acute arterial hypertension. Effect of unilateral ligation of the common carotid artery.

Ligation of the right common carotid artery prevented protein extravasation in the homolateral cerebral hemisphere when a blood pressure increase was induced by bicuculline or amphetamine. In addition to a blood pressure increase these two drugs induce a vasodilatation, which makes the resistance vessels particularly vulnerable to the mechanical stress of high intravascular pressure. The ratio between the mean arterial blood pressure in the femoral artery and the carotid artery distal to the ligation was approximately 0.

[Tissue compatibility of bone cement with and without barium sulfate (author's transl)].

Cylindrical plugs of polymerized Simplex-P bone cement with and without barium sulfate were implanted in the rabbit tibial metaphysis. Titanium was used as control material. The animals were observed for 4--4.

Reaction of bone to the acute chemical trauma of bone cement.

The acute chemical trauma of bone cement was investigated in the rabbit tibia. With the experimental model used, the surgical trauma and the thermal effects of the cement could be minimized. Each animal received one implant of polymerized cement as a control and one implant of polymerizing dough as the test material.