Variability of the superficial veins of the dog cerebrum with age

In 42 dogs of the nine different ages, age changeability of the brain superficial veins is described in details. Topographic-anatomical peculiarities of the dog closely resemble those of the man and, moreover, the dog is often used as an experimental model. The work fills up one of the gaps in age morphology of the experimental animals. Besides, the data represented will help to make further conclusions, comparisons and experiments.     

Biostatistical study on the arrangement of the superficial veins of the cubital fossa in Iraqis

A study of the arrangement of the superficial veins of the cubital fossa was made on 300 students and staff of the Military Medical College and the AlMustansiriya College of Medicine. Six types of variations of arrangement of the veins were found, two of which have not been mentioned before. The commonest type was that the median vein of the forearm divides in the cubital fossa into 2 veins, one of which joins the basilic vein, and the other the cephalic vein, although in a few cases this joining (or arrangement), occurred above the cubital fossa. The arrangements which have not been mentioned before were that the communication between basilic and cephalic veins was through a horizontal venous connection between 1 of the tributaries of these 2 veins and the basilic vein, and that the median vein of the forearm divides into median cephalic and median basilic, and a vein from the front of the forearm drains into the median basilic vein.     

Morphology of superficial postnatal cerebral cortex with special reference to synapses

Summary The ultrastructure of layers I and II of the motor cerebral cortex of rat brain has been studied at birth, 4, 7 and 14 days postnatal and in the adult.Compared with the adult, neonatal rat motor cortex exhibited a large extracellular space which decreases with increasing age. At all stages studied the neurons were seen to contain the organelles usually found in adult neurons. Growth cones were present in decreasing numbers up to 14 days old.Synapses were detectable at birth and there was an obvious increase in their number throughout the postnatal development. At the earliest stages studied there was a lack of specialization characteristic of the adult. Many synapses were either avesicular or relatively so and lacked the high degree of modification of adult pre- and postsynaptic membranes. By 7 days after birth many synapses existed which in all morphological respects resembled those of the adult, and by 14 days, the majority were of the adult type.These findings, particularly with reference to the postnatal development of synapses, have been discussed in relation to the known electrophysiological findings.The authors wish to express their thanks to Mr. R. Birchenough and Mr. J. Manston for their technical assistance.     

The influence of steroids on vascular tension of isolated superficial veins of the nose and face during the estrous cycle of gilts

The arrangement of the superficial facial veins enables blood flow from the nasal cavity into the peripheral circulation by two pathways: through the frontal vein into the cavernous sinus and through the facial vein into the external jugular vein. The current study was designed to determine whether estradiol and progesterone affect the vascular tone of the superficial veins of the nose and face in cycling gilts (Sus scrofa f. domestica) and to analyze the immunolocalization of progesterone receptors and estradiol receptors in these veins. The influence of hormones on vascular tension differed depending on the type of vessel and the phase of the estrous cycle. Estradiol decreased vascular tension in the nasal vein during the follicular phase (P < 0.05) and increased tension in the frontal vein during the luteal phase (P < 0.05). Progesterone increased the vascular tension of the frontal vein (P < 0.05) and decreased the tension of the other veins (P < 0.05) in both phases of the cycle. Expression of estradiol receptor β but not of progesterone receptor was observed in the superficial veins of the nose and face. In conclusion, the effect of ovarian steroid hormones on the vascular tension of the superficial veins of the nose and face in female pigs as well as the reactivity of these veins to steroid boar pheromones can affect the blood supply from the nasal cavity to the venous cavernous sinus. We propose that the ovarian steroid hormones that modulate the vascular tension of the nasal and facial veins may also influence the action of boar pheromones absorbed into the nasal mucosa in gilts and may reach the brain via local destination transfer.     

Effects of elastic compression stockings on wall shear stress in deep and superficial veins of the calf

The purpose of this study was to estimate wall shear stress (WSS) in individual vessels of the venous circulation of the calf and quantify the effects of elastic compression based on change of vessel geometry and velocity waveform. The great saphenous vein and either a peroneal or posterior tibial vein have been imaged in four healthy subjects using magnetic resonance imaging, with and without the presence of a grade 1 medical stocking. Flow through image-based reconstructed geometries was numerically simulated for both a range of steady flow rates and ultrasound-derived transient velocity waveforms, scaled to give a standardized time averaged flow rate. For steady flow, the stocking produced an average percentage increase in mean WSS of approximately 100% in the great saphenous vein across a range of 0.125-1.25 ml/s. The percentage increase in the peroneal/posterior tibial veins varied from 490 to 650% across a range of 0.5-5 ml/s. In addition, application of the stocking eliminated periods of very low or zero flow from the transient waveforms. The average minimum value of WSS in all vessels without the stocking was <0.1 Pa. With the stocking, this was increased to 0.7 Pa in the great saphenous and 0.9 Pa in the peroneal/posterior tibial veins. The pathophysiological effects of these changes are discussed. In conclusion, the flight stocking was effective in raising venous WSS levels in prone subjects, and this effect was much more pronounced in the deep vessels. The stocking also tended to prevent cessation of flow during periods of increased downstream pressure produced by respiration.     

Interaction of histamine with noradrenergic constrictory mechanisms in cat cerebral arteries and veins

We examined responses of pial arteries and veins in situ to noradrenergic stimuli in the presence of histamine. Electrical stimulation of sympathetic nerves and perivascular microapplication of norepinephrine in mock cerebrospinal fluid produced constriction of arteries and veins in anesthetized cats. During simultaneous perivascular injection of histamine, these noradrenergic responses were attenuated or reversed. In both arteries and veins, constriction from sympathetic nerve stimulation was prevented by simultaneous application of the histamine receptor agonists, pyridylethylamine (H1) or impromidine (H2), results that suggest interference involving both types of histamine receptors. In arteries, impromidine, but not pyridylethylamine, inhibited constriction resulting from exogenous norepinephrine. Our findings indicate that histamine may have an inhibitory influence, exerted through both receptor types, on noradrenergic mechanisms in cerebral vessels.