Effect of chlordiazepoxide on schedule-controlled responding and schedule-induced drinking

Polyovular follicles and polynuclear ova have been recorded to occur only in 5 goats out of 24 goats of ages between 2 months 24 days and 5 years 2 months 18 days, studied. These structures were recognized at proestrus, estrus and metestrus only but never in the animals over 1 year of age. Polyovular and polynuclear follicles with no apparent degenerative changes were seen at estrus whereas degenerating ones were commonly seen at proestrus and metestrus also.     

The effect of nitrate and nitrite on the respiration and cytochrome system of Rhizobium lupini]

Chromosome replication has been analysed in four species of Chilocorus. In C. ORBUS Csy., C. tricyclus Smith, and C. hexacyclus Smith, centric regions of all chromosomes are last to replicate, preceded in order by heterochromatic arms and euchromatic arms. In C. stigma Say, very late replication of centric regions can be detected only in otherwise wholly euchromatic chromosomes (= monophasics); in chromosomes with one arm heterochromatic ( = disphasics), these arms are last to replicate. Based on pachytene bivalent morphology and chromosome banding patterns, and supported by autoradiographic data, models are presented for the general organisation of Chilocorus chromosomes. All chromosomes in the first three species are subdivided into euchromatic arm, centric heterochromatin, and either a second euchromatic are (monophasics) or a heterochromatic arm (diphasics). Chilocorus stigma diphasics apparently lack distinct centric organisation, and are therefore divided into euchromatic and heterochromatic arms only.     

Effect of umbilical artery catheters on blood flow and oxygen supply to extremities

The effect of catheter placement in the abdominal aorta on the blood flow and oxygenation of lower extremities was evaluated in 30 New Zealand rabbits, weighing 0.55-3.5 kg, by inserting 3.5 and 5.0 French polyvinyl chloride catheters, of the type commonly used for umbilical artery catheterization, through the femoral artery, advancing 15-20 cm, and leaving in place for 10-30 min. Arterial blood pressure (BP), common iliac artery blood flow (BF), gracilis muscle tissue oxygen availability (O2a), and subcutaneous temperature (T) in the foot were continuously monitored before and during catheter placement and after withdrawal. There were no changes in the physiologic variables measured in the contralateral leg when the catheter remained below the aortic bifurcation; however, when the catheter was advanced 15-20 cm into the abdominal aorta, a decrease in lower extremity BF, O2a, and T occurred. Because the length of catheter insertion was maintained constant in each animal, the decreases in BF, O2a, and T are related to the relative dimensions of the vessel and the catheter. The ratio of catheter to vessel diamter, in addition to the site of catheter placement, should be considered during the clinical application of arterial catheters. Reduction in blood flow could be detected by continuous differential monitoring of core and extremity temperature or extremity muscle oxygen availability.     

Atherosclerotic (systolic) hypertension

Systolic hypertension was studied in 92 patients, aged 60 to 103 years, some of them being followed-up for periods up to 8 years. The examination included that of haemodynamics, functional state of the heart and gas composition of blood (by the dye dilution technique, polycardiography, teleradiography, Sechenov and van Slyke methods, the micro-Astrup technique). The previously reported concept of the author was proved, i.e. the immediate haemodynamic cause of arterial pressure elevation in this pathology consists in an increased cardiac output against the background of an increased total elastic resistance of the arterial system. The elevation of the cardiac output is due not only to the neuro-humoral disorders in the regulation of arterial pressure in old age, but also to the adaptational factors directed to the improvement of oxygen transport and consumption by the tissues when the premeability of the vascular-tissuemembranes is impaired.     

The cardiovascular effects of diazepam and of diazepam and pancuronium during fentanyl and oxygen anaesthesia

A study of the physiological behaviour of the synthetic compound Orthonil (alpha-chloro-beta-(3-chloro-o-tolyl)-propionitrile revealed a strong auxin activity in higher plants. Otherwise, Orthonil appeared not to be a herbicide-auxin. It is metabolized intensively in plant tissues. Among the identified metabolites, two compounds were detected which also exert a high auxin activity. It is concluded that at least a part of the apparent auxin activity of Orthonil may be due to alpha-(3-chloro-o-tolyl) acetic acid, one metabolite of Orthonil. Although Orthonil strongly stimulates elongation growth, this growth is not accompanied by a stimulated ethylene evolution as is the case with other auxins. A possible metabolic pathway of Orthonil is discussed.     

Cholinergic innervation of vessels of the base of the brain

Distribution and activity of acetylcholinesterase in the intramural nerve apparatus of vessels of the base of the bran have been studied with the histochemical method of Koelle-Gomori. On the whole, 268 arteries have been examined. The activity of the ferment is detected in the effector nerve fibers in the wall of all cerebral vessels constituting the system of the circle of Willis. The periarterial nerve apparatus of cerebral arteries of the anterior and posterior regions of the circle of Willis consists of two cholinergic plexuses - superficial and deep plexus forming a multilayered neural cover. The terminal parts of cholinergic nerve fibres at the border with the muscular coat show a granular structure. Moreover, nerve cells rich in active ferment are found in the cholinergic plexuses. Difference in the character of cholinergic innervation of vessels of the internal carotid and the vertebrobasilar region has been shown. The obtained data indicate that the vessels of the circle of Willis possess a reliable cholinergic system of nerve regulation which along with other systems, such as that of adrenergic nerve fibers, maintains the homeostasis of the cerebral blood flow.