Using selective agonists and antagonists of alpha2 adrenoceptors, attempts were made to identify the subtype alpha2 adrenoceptors in the blood vessels of the canine dental pulp. In chloralose-anaesthetized dogs, intra-arterial administration of noradrenaline and guanabenz in different doses produced a dose-related pulpal vasoconstriction which was measured using hydrogen-gas clearance. The vasoconstrictor response to noradrenaline was inhibited by phentolamine, a non-selective alpha adrenoceptor antagonist. The response to guanabenz was inhibited by rauwolscine, a highly selective alpha2 adrenoceptor antagonist. The results demonstrated that alpha2 adrenoceptors are present in the blood vessels of dog dental pulp.

Experiments were carried out on 25 grown-up dogs of both sex in general anesthesia. The supraduodenal part of the choledochus was excised and the reconstruction of the defect with a free venous autograft was made by an end to end anastomosis without use of a transitory or permanent prosthesis. The experimental animals were observed for 60 days, during which period they were checked clinically, biochemically and radiologically. After this period the animals were sacrificed and surgical peroperative control and sampling of material for histological study were made. Out of 25 experimental animals 18 (72%) survived a period of 60 days and 7 dogs died. On autopsy it was found that the cause of death in all animals was biliary peritonitis, but in only one case due necrosis of the graft. The values of bilirubin concentration at the end of the experiment showed almost normal level, but the values of the alkaline phosphate activity and transminase showed significant increased values. Intravenous biligraphy showed significant excretion of the contrast material, freely passing the graft, which was dilated due to stenotic changes of the distal anastomosis. After sacrificing the animals we found: the graft increased length, diameter, thickness wall and stenosis of the distal anastomosis. By histological exploration we found in the liver the signs of the biliary stasis and in the grafts substitution of its endothelium by biliary epithelium. Free venous autograft used as a substitute in the reconstruction of the bile duct which survived 60 days postoperatively, remained transient but with changes in the sense of elongation and dilatation caused by the stenosis od distal anastomosis. Histologically the grafts were entirely bridged by biliary epithelium.

In previous reports it was found that in mesenteric blood vessels exist profound alpha-adrenergic, and less profound beta-adrenergic receptors. Our experiments were done on 20 mongrel dogs, both sexes, weighing 6.5-22.5 kg, age from 1-2 years, which were divided into 2 groups: experimental (14 dogs) and control (6 dogs). Experimental group of animals passed through the posthemorrhagic hypotension (180 min. at 5.3 kPa). Aim of investigation was to clarify mesenteric vascular reactivity changes during posthemorrhagic hypotension. In order to reach this goal, phenylephrine and isoproterenol were injected alternatively in one hour intervals through cannulated superior mesenteric artery first proximal branch. Our results indicate that mesenteric blood flow responses to those drugs changed quantitatively, but never ceased. It is apparent from our experiments that those quantitative changes are due to beta 2 adrenoceptors changes during the posthemorrhagic hypotension.

The liver blood flow has been extensively studied in hemorrhagic shock, but considerable disagreement exists as to the nature of hemodynamic changes and their controlling mechanism. The present investigation was undertaken in order to determine the effects of hemorrhage and phenoxybenzamine (PBZ) on the participation of hepatic artery (HAF) and portal vein flow (PVF) in total liver blood flow (LBF) changes. The dynamics of LBF (H2 washout method), HAF and PVF (electromagnetic flowmeter) during 3-hours posthemorrhagic hypotension (90 min. = 50-60 mmHg; 90 min. = 25-30 mmHg) and one-hour postretransfusion period were investigated on 20 mongrel dogs under chloralose anesthesia. All animals were divided into 2 groups (control and PBZ-treated--5 mg/kg b.w. 30 minutes following first bleeding). Half an hour following bleeding there occurred a significant decrease of LBF (P less than 0.001) in dogs of both experimental groups. This degree of decrease was due to equal decrease in the PVF and HAF. The infusion of PBZ caused a slight tendency towards increase of LBF, while the subsequent decrease in blood flow values during second hypotensive period in the treated dogs was not so pronounced as in the untreated dogs. Although retransfusion led to an increase of LBF, HAF and PVF in both groups, the restauration was significantly better in PBZ-treated animals. The degree of metabolic acidosis was more pronounced in the untreated dogs than in PBZ-treated.

In seven dogs, the authors performed a resection of the supraduodenal part of the main bile duct, 15-2 cm. in length. The arising defect was bridged over with a free autovenous graft taken from the exterior jugular vein (T-T anastomosis), without using a temporary or permanent prosthesis. The animals were followed-up 60 days and the sacrificed. Three dogs perished: the first one on the third day due to intoxication, the second dog on the thirteenth day because of anastomosis' disruption and consequent biliary peritonitis, and the third one on the eighteenth day of unknown causes. In the immediate postoperative course the values of the bilirubin and alkaline phosphatase were increased while those of transaminase were not significantly altered. These values began to normalize during the third week. An intravenous biliography was made on the sixtieth day showing a normal filling of the gallbladder, with an orderly visualization of hepato-choledochus and its correct transit, but with stenosis at the distal anastomosis. Macroscopically, the graft appeared slightly enlarged in length and diameter due to the mentioned stenosis. Histologically, the graft took on an appearance similar to the main bile duct, while its endothelium was completely replaced by biliary epithelium. An answer about the viability of this autovenous graft to serve as a substituent of a normal common bile duct is to be expected with further experimental work.