Basal metabolism adds a significant offset to unloaded myocardial oxygen consumption per minute.

Myocardial oxygen consumption (MVO2) includes components for 1) mechanical energy generation, 2) activation, and 3) basal metabolism. Whereas the first two components are expected to increase in proportion with heart rate, a significant basal level of metabolism would consume oxygen even if the heart rate were zero. Contrary to this expectation, however, a previous study reported that, during unloaded beats, MVO2 per beat (which includes basal metabolism) was independent of heart rate. Accordingly, unloaded MVO2 per minute would extrapolate to zero at zero heart rate; this result is unexpected considering basal metabolism. To resolve this inconsistency, we varied heart rate over a wide range after inducing atrioventricular block in eight isolated cross-circulated canine hearts that contracted isovolumically. We examined whether a term representing rate-independent basal metabolism was needed to describe MVO2 per minute. Mechanical energy generated by the left ventricle was evaluated from the pressure-volume area, which was altered by changing isovolumic ventricular volume over at least five levels at each heart rate. Contractility, evaluated by the slope of the end-systolic pressure-volume relation, did not vary significantly with heart rate in this study. In contrast to the previous report, unloaded MVO2 per beat (i.e., MVO2 extrapolated to a pressure-volume area of zero) was not constant but fell monotonically with increases in heart rate in every heart. We considered that this trend was caused by a significant rate-independent basal level of MVO2 per minute. Multiple linear regression analysis confirmed that this rate-independent basal term differed significantly from zero in seven of the eight hearts studied.(ABSTRACT TRUNCATED AT 250 WORDS)     

Congenital lumbar hernia in association with carpus equina varus.

A rare case of congenital lumbar hernia associated with carpus equina varus is described in a week old baby. The treatment is described with limited review of the literature.     

Anxiolytic-like effects of yohimbine in the murine plus-maze: strain independence and evidence against α2-adrenoceptor mediation

The influence of ₂-adrenoceptor antagonists in animal models of anxiety is quite inconsistent, with results spanning the full range of effect from anxiogenesis to anxiolysis. In the present study, an ethological technique was used to examine the effects of yohimbine (0.5–4.0 mg/kg) on plus-maze behaviour in DBA/2 mice. Results indicated significantanxiolytic-like effects on standard spatiotemporal measures at 2.0–4.0 mg/kg, and on risk assessment measures across the entire dose range. Full-scale follow-up studies with T1 and BALB/c strains confirmed that this action of yohimbine in the murine plus-maze is not peculiar to DBA/2 mice. The more selective ₂-adrenoceptor antagonist, idazoxan (0.63–5.0 mg/kg), exerted much weaker behavioural effects in the maze while the ₂-adrenoceptor agonist, clonidine (0.01–0.1 mg/kg), produced a profile consistent with non-specific behavioural disruption. Data are discussed in relation to the possible involvement of 5-HT_1A receptor mechanisms in the observed anxiolytic-like effects of yohimbine in the murine plus-maze.     

An investigation into the effects of polishing on surface hardness and corrosion of orthodontic archwires.

The purpose of this study was to investigate the effect of surface roughness on the relative corrosion rates of wires of four alloys-stainless steel, nickel titanium, cobalt chromium, and beta titanium. Batches of wire were divided into two groups. Wires in one group were industrially polished to provide a uniform surface finish; wires in the other group were left for comparison "as received." Wire diameter, hardness, and relative corrosion rates were compared within groups before and after polishing. Comparisons were also made across the four groups of alloys. The samples of as-received wires showed variations in surface finish, with beta titanium having the roughest appearance and cobalt chromium the smoothest. Nickel titanium and stainless steel surfaces were similar. Polishing provided a more uniform finish, but significantly reduced the diameter of the wires. Microhardness testing of wire surfaces of each alloy indicated that no significant work-hardening occurred as a result of polishing. The relative corrosion rates (expressed in terms of corrosion current density) in a 0.9% sodium chloride solution were estimated using the electrochemical technique of polarization resistance. Nickel titanium wires exhibited the greatest corrosion current density in the as-received state. Polishing significantly reduced the corrosion rate of nickel titanium, such that comparison between the four alloys in the polished state revealed no significant difference in their relative corrosion rate/corrosion current density.     

Effect of Momordica charantia on the glucose tolerance in maturity onset diabetes

Investigations were carried out to evaluate the effect of Momordica charantia on the glucose tolerance of maturity onset diabetic patients. The fruit juice of M. charantia was found to significantly improve the glucose tolerance of 73% of the patients investigated while the other 27% failed to respond.     

Effects of Salvadora persica extracts on mice exploratory locomotion activities

The effects of Salvadora persica extracts on mice exploratory locomotor activities and stereotype movements have been determined. Mice injected with Salvadora persica extracts showed significantly low exploratory locomotor activity. The total distance travelled by naive mice injected with saline, during the first 5 min of introduction into an activity cage (Session 1) was 1007 +/- 105 cm/5 min, in contrast to 800 +/- 75, 540 +/- 100 and 330 +/- 55 cm/5 min for naive mice injected i.p. with 5.7, 14.3 and 28.6 ml/kg Salvadora persica extract. The exploratory locomotion of Salvadora persica treated mice declined faster than that of the controls. Mice injected with Salvadora persica extract also showed a significantly lower number of stereotype movements (P less than 0.05). The stereotype movements of the control was 175 +/- 5 movements/5 min and 90 +/- 10, 118 +/- 15 and 35 +/- 11 for mice injected with 5.7, 14.3 and 28.6 ml/kg, Salvadora persica extract, respectively.