Interaction between neuronal nitric oxide synthase and inhibitory G protein activity in heart rate regulation in conscious mice

Nitric oxide (NO) synthesized within mammalian sinoatrial cells has been shown to participate in cholinergic control of heart rate (HR). However, it is not known whether NO synthesized within neurons plays a role in HR regulation. HR dynamics were measured in 24 wild-type (WT) mice and 24 mice in which the gene for neuronal NO synthase (nNOS) was absent (nNOS-/- mice). Mean HR and HR variability were compared in subsets of these animals at baseline, after parasympathetic blockade with atropine (0.5 mg/kg i.p.), after beta-adrenergic blockade with propranolol (1 mg/kg i.p.), and after combined autonomic blockade. Other animals underwent pressor challenge with phenylephrine (3 mg/kg i.p.) after beta-adrenergic blockade to test for a baroreflex-mediated cardioinhibitory response. The latter experiments were then repeated after inactivation of inhibitory G proteins with pertussis toxin (PTX) (30 microgram/kg i.p.). At baseline, nNOS-/- mice had higher mean HR (711+/-8 vs. 650+/-8 bpm, P = 0.0004) and lower HR variance (424+/-70 vs. 1,112+/-174 bpm2, P = 0.001) compared with WT mice. In nNOS-/- mice, atropine administration led to a much smaller change in mean HR (-2+/-9 vs. 49+/-5 bpm, P = 0.0008) and in HR variance (64+/-24 vs. -903+/-295 bpm2, P = 0.02) than in WT mice. In contrast, propranolol administration and combined autonomic blockade led to similar changes in mean HR between the two groups. After beta-adrenergic blockade, phenylephrine injection elicited a fall in mean HR and rise in HR variance in WT mice that was partially attenuated after treatment with PTX. The response to pressor challenge in nNOS-/- mice before PTX administration was similar to that in WT mice. However, PTX-treated nNOS-/- mice had a dramatically attenuated response to phenylephrine. These findings suggest that the absence of nNOS activity leads to reduced baseline parasympathetic tone, but does not prevent baroreflex-mediated cardioinhibition unless inhibitory G proteins are also inactivated. Thus, neuronally derived NO and cardiac inhibitory G protein activity serve as parallel pathways to mediate autonomic slowing of heart rate in the mouse.     

The choice of the method for the surgical treatment of bladder exstrophy

129 children with exstrophy of the bladder underwent primary surgical reconstruction according to G. A. Bairov. Morphofunctional findings in these children gave grounds for determination of three degrees of the bladder congenital defects. 39 patients had defect of the 1st degree, 53 of the 2nd and 37 of the 3d degree. The results of plastic reconstruction of the bladder with local tissue support the validity of such procedure only for patients with the congenital defect degree I. For degree II the benefit is relative. In degree III plastic surgery in contraindicated.     

Effects of total coumarins, essential oil and water extracts of Cnidium monnieri on plasma prostaglandin and cyclic nucleotide in the rats of kidney-yang insufficiency

Effects of total coumarins, essential oil and water extracts of Cnidium monnieri on plasma prostaglandin (PGE2 and PGF2 alpha) and cyclic nucleotide levels in rats of Kidney-Yang insufficiency were studied. 55 rats were divided randomly into 5 groups, Group I was administered orally with saline (normal group), group II was injected with intraperitonally hydrocortison acetate to induce Kidney-Yang insufficiency (control group), group III, group IV and group V (experimental groups) were injected with hydrocortison acetate, the same as group II, and administered orally with the total coumarins, essential oil and water extracts of Fructus Cnidii respectively. The levels of plasma PGE2, PG2 alpha and plasma cAMP, cGMP were measured. In group II, in comparing with those of group I, the levels of plasma PGE2, and PGF2 alpha decreased significantly (P < 0.01), and the value of cAMP/cGMP also lowered obviously (P < 0.01) due to the significant reduction of cAMP and insignificant change of cGMP. In group III and group V, the above-mentioned indices changed significantly (P < 0.01 or 0.05) compared with those of group II, and after treatment it normalized basically in comparing with those of group I. In group IV, those indices didn't change regularly and apparently as group III and group V did, compared with group II, and could not normalize satisfactorily. It is suggested that the coumarins in the fruit of Cnidium monnieri are probably the effective ingredients to invigorate Kidney and strengthen Yang, while the efficacy of essential oil remained unconfirmed.     

Pneumomediastinum following a surgical renal biopsy

A case of pneumomediastinum, which appeared after a biopsy of the right kidney by minimal lumbotomy, is reported. The anatomicopathological condition of the renal fragment obtained was judged to be focal and segmental hyalinosis. We wish to emphasize the rarity of such a complication, the type of electrocardiographic changes observed, and the rapid and spontaneous recuperation of the patient without further repercussions.     

Racial differences in muscle strength in disabled older women

This study examines racial differences in muscle strength, and associations of muscle strength to level of physical activity and severity of disability, among a community sample of 254 black and 665 white, moderately to severely disabled women aged 65 and older. Potential confounders that were adjusted for in the models included age, body weight and height, joint pain, number of chronic conditions, and socioeconomic status. Hand grip, hip flexion, and knee extension forces were measured using portable hand-held dynamometers in the participants' homes. Hand grip strength was measured as the maximal isometric force. Hip flexion and knee extension forces were measured as the greatest force the tester had to apply to break the isometric contraction. A declining strength gradient was observed with increasing severity of disability and for decreasing level of physical activity in both races. At equal levels of disability or physical activity, blacks had better hand grip and hip flexion strength, but knee extension strength did not differ by race. The greater hand grip and hip flexion strength found in black women may be related to their greater muscle mass and known racial differences in body dimensions. No consistent racial differences were observed in the relationship between physical activity and muscle strength, or muscle strength and disability, suggesting that the role of muscle strength in the disablement process does not differ between races. Physical activity and exercise programs may be feasible ways to prevent worsening of disability in blacks and whites.