Vasomotor changes in isolated coronary arteries from diabetic rats

Contractile responses to prostaglandin F2 alpha, serotonin, noradrenaline, and potassium were examined in isolated intramyocardial arteries of Wistar rats 8 weeks after the induction of diabetes mellitus by administration of streptozotocin (STZ). The concentration-response curves obtained were compared with those noted in vessels both from age- and from weight-matched control rats. Light and electron microscopy did not reveal any major change in coronary artery wall thickness or morphology. There was no difference in the pattern of vasomotor responses between the two control groups. Contractile responses to prostaglandin F2 alpha, and potassium were significantly reduced, while contractile responses to serotonin and noradrenaline were unaltered in coronary arteries from diabetic rats. The vasomotor responses to noradrenaline and potassium showed a biphasic pattern in control vessels, i.e. contraction noted at high agonist concentrations was preceded by slight, but reproducible relaxation at lower concentrations. In diabetic vessels these relaxant responses were absent. The contraction produced by noradrenaline was markedly enhanced by the presence of propranolol in both diabetic and control vessels. Dilator responses to verapamil, diltiazem, nifedipine, papaverine and magnesium were studied in serotonin-precontracted coronary arteries; the concentration-response curves obtained by verapamil and diltiazem were shifted to the right in diabetic vessels. It appears justified to use vessels from age-matched rats as controls when vasomotor reactivity in coronary arteries from STZ-diabetic rats is investigated. The reduction in contractile responses to prostaglandin F2 alpha and potassium, and the reduction or lack of relaxant responses to noradrenaline, potassium, verapamil and diltiazem, in diabetic coronary arteries, indicate a selective modification of the coronary circulation by the diabetic disease.     

Diameters of arteries, veins, and airways in isolated dog lung

Triple resin casts were made of the pulmonary arteries, veins, and airways from six dog lungs. The airways were cast at a pressure of 25 cm resin in all six. In the first three, both vessels were cast at a pressure of 30 cm resin, and in the second three, arteries were at 10 cm resin and veins at 5 cm resin. Measurements were made of luminal airway diameters down to 1 mm and of the luminal diameters of the corresponding segments of the vascular trees. The relation of one to the other was shown by calculating the regression lines for the corresponding diameters. Intrapulmonary arteries and veins are of approximately equal diameter when cast at 30 cm resin, while the veins are 20% larger than the arteries when cast at 5 cm and 10 cm of resin, respectively. Both vessel diameters are 75% of bronchial at the higher pressure, while at the lower pressures arteries are 59%, and veins 71% of bronchial. In any individual, vessel diameters are a relatively constant proportion of airway diameter. This constant of proportionality varies considerably between dogs, its value ranging from 0.48 to 1.03. It is concluded that in any individual all three trees have similar diameter ratios--that is, the ratio between mean diameters of branches in successive orders.     

Pharmacological characterization of postjunctional alpha-adrenoceptors in isolated human omental arteries and veins

The alpha-adrenoceptors in human omental arteries and veins were characterized and compared. In the arteries both prazosin (pA2 9.48) and rauwolscine (pA2 7.19) displaced the noradrenaline (NA) concentration-response (cr) curve towards higher concentrations without reduction of maximum. Neither clonidine, nor oxymetazoline had any consistent contractile effects. Phenylephrine had a lower potency than NA, but a similar intrinsic activity. In the veins, both prazosin (pA2 9.72) and rauwolscine (pA2 8.11) displaced the NA cr-curve towards higher concentrations, but also significantly depressed maximum. Clonidine and oxymetazoline contracted veins from 3 out of 7 and 4 out of 6 patients, respectively. Their pD2-values were similar to that of NA, but their intrinsic activities were significantly lower. NA was more potent than phenylephrine in these vessels, and there was no significant difference in intrinsic activity. The results suggest that in human omental arteries, the postjunctional alpha-adrenoceptors are mainly of the alpha 1-type, even if a small population of alpha 2-adrenoceptors cannot be excluded. In omental veins, there seems to be a functionally important population of postjunctional alpha 2-adrenoceptors occurring together with a population of alpha 1-adrenoceptors.     

Vasomotor control mechanisms

Summary The author investigated the relationship of reflexes on arterial pressure (systemic) and regional reflexes on the blood vessels of kidneys and a portion of small intestine caused by stimulation of mechanoceptors of the urinary bladder, large and small intestine, carotid sinus and the tibial nerve. The regional reflexes were registered by the method of resistography (autoperfusion with stabilized minute blood volume). A definite relationship exists between the values of systemic and regional reflexes elicited from each receptor zone. These data show the existence of definite complexes of regional vasomotor reflexes caused by stimulation of the given interoceptive zone and point out the fractionation of reflexes in the centers of vasomotor regulation.Presented by Active Member of the AMN SSSR V. N. Chernigovskii     

Myxoma-like features of organizing thrombi in arteries and veins.

Evidence for the development of the cardiac myxoma from organizing thrombi has been presented previously. In this study, many of the features of the myxoma were observed in organizing thrombi in arteries and veins. Individual undifferentiated mesenchymal cells, cords of similar cells, vascular bud-like cellular aggregates, fibroblasts, well-formed vessels, and multiwalled vessels set within a loose, mucoid ground substance were present in the thrombi. These areas resembled the basilar layer of the cardiac myxoma. Cartilage-like cells, like those in the superficial zone of myxomas, were noted in some thrombi, and ossification had occurred rarely. These observations support a thrombogenic origin of the myxoma. Local physical factors may provide the stimulus for varying differentiation of mesenchymal cells in both the peripheral thrombi and the myxoma.     

右侧肾动静脉及睾丸动静脉变异1例

在解剖一具成年男性标本时发现其有3条右肾静脉和两条右睾丸静脉，并且右睾丸动脉起点和右睾丸静脉静脉汇入处，以及右肾动脉的行程上均有变异。此类多变异共存现象尚未见有文献报道，现报道如下：     

Pulmonary arteries and veins in experimental hypoxia. An ultrastructural study.

Pulmonary vessels of rats were studied electron microscopically after 4 days to 4 weeks of hypoxia and were compared with those of control rats and of "regression" rats that, after a period of hypoxia, were allowed to survive in normal air for up to 4 weeks. Both the hypoxic and the regression rats had medial hypertrophy, not only of arteries and arterioles but also of veins and venules. In contrast to the control and the regression rats, many of the hypertrophic vessels of all types in the hypoxic rats showed signs of constriction, ie, crenation of the wall, indentations of medial smooth muscle cell nuclei, and excrescences of smooth muscle cell cytoplasm, often protruding deeply into the endothelium. These observations permit the following conclusions: a) Vasoconstriction due to hypoxia is not confined to pulmonary arteries and arterioles, as generally assumed, but also occurs in veins and venules. b) Medial hypertrophy may be found in the absence of vasoconstriction; this is especially evident during recovery from hypoxia.     

Intersection patterns of human coronary veins and arteries

Intersections between the coronary veins (CV) and arteries (CA) of 103 adult human hearts were mapped on the heart surface. Then the correlations of these intersection patterns to their localization were studied. Eight spots were selected where one of four major CV (anterior cardiac vein, middle cardiac vein, left posterior ventricular vein, and great cardiac vein) intersected with one of CA and their branches (right coronary artery, posterior interventricular branch, left posterior ventricular branch, circumflex branch, diagonal branch, and anterior interventricular branch). The great cardiac vein (GCV) ran beneath the anterior interventricular branch in 56 specimens out of 103, beneath the diagonal branch in 75 specimens out of 103, and beneath the circumflex branch in 36 specimens out of 103, while the other CV mostly ran over CA. The present observations suggest that the CV on the right side may be formed prior to CA, while the CV on the left side may be formed simultaneously with CA.     

Pharmacological characterization of postjunctional α-adrenoceptors in isolated human omental arteries and veins

The α-adrenoceptors in human omental arteries and veins were characterized and compared. In the arteries both prazosin (pA₂ 9.48) and rauwolscine (pA₂ 7.19) displaced the noradrenaline (NA) concentration-response (cr) curve towards higher concentrations without reduction of maximum. Neither clonidine, nor oxymetazoline had any consistent contractile effects. Phenylephrine had a lower potency than NA, but a similar intrinsic activity. In the veins, both prazosin (pA₂ 9.72) and rauwolscine (pA₂ 8.11) displaced the NA cr-curve towards higher concentrations, but also significantly depressed maximum. Clonidine and oxymetazoline contracted veins from 3 out of 7 and 4 out of 6 patients, respectively. Their pD₂-values were similar to that of NA, but their intrinsic activities were significantly lower. NA was more potent than phenylephrine in these vessels, and there was no significant difference in intrinsic activity. The results suggest that in human omental arteries, the postjunctional a-adrenoceptors are mainly of the α₁-type, even if a small population of α₂-adrenoceptors cannot be excluded. In omental veins, there seems to be a functionally important population of postjunctional α₂-adrenoceptors occurring together with a population of α₁-adrenoceptors.     

Postjunctional alpha 1- and alpha 2-adrenoceptors mediating contraction in isolated human groin arteries and veins

By means of selective agonists and antagonists for alpha 1- and alpha 2-receptors, the alpha-receptor subtypes in human groin arteries and veins were characterized and compared. In the arteries the alpha 1-receptor blocker prazosin caused a concentration-dependent parallel displacement of the noradrenaline (NA) concentration-response (cr) curve without reduction of maximum (pA2 = 9.86); the selective alpha 2-receptor antagonist rauwolscine in the concentration 10(-8) M caused a right-ward shift of the NA cr-curve without reduction of Emax, but 10(-7) M and 10(-6) M caused little or no further shift. In the veins, the two antagonists had the opposite effects. Rauwolscine caused a concentration-dependent right-ward shift of the NA cr-curve without depression of maximum (pA2 = 9.03); prazosin 10(-9) M significantly displaced the NA cr-curve, whereas 10(-8) M and 10(-7) M caused little or no further shift. The responses to the alpha 2-receptor agonist clonidine in the arteries were too small to allow calculations of pEC50 values; in the veins contractions were elicited in all vessel segments investigated (pEC50 = 6.24). Phenylephrine, selective for alpha 1-receptors, was significantly more potent in arteries than in veins. NA was significantly more potent in veins than in arteries. It is concluded that in human groin vessels, there is a functional predominance of alpha 1-receptors in the arteries and of alpha 2-receptors in the veins.     

Duplicate testicular veins accompanied by anomalies of the testicular arteries.

Duplicate testicular veins associated with other anomalies of the testicular arteries were observed during dissection of the posterior abdominal wall in a 90-year-old Japanese male cadaver. The right testicular vein was composed of the medial and lateral testicular veins. The medial testicular vein drained into the inferior vena cava, whereas the lateral testicular vein drained into the confluence of the inferior vena cava and right renal vein. Several anastomosing branches were seen between the medial and lateral testicular veins. The left testicular vein was formed after the medial and lateral venous trunks joined and drained into the ipsilateral renal vein. The right testicular artery originated from the anterior surface of the abdominal aorta at the level of the left renal artery, passed posterior to the inferior vena cava, and accompanied the right lateral testicular vein running downwards. The left testicular artery arose from the abdominal aorta at a level of 5 cm below the origin of the right testicular artery, and then ran downwards accompanied by the medial trunk of the left testicular vein.