Sperm nitric oxide and motility: the effects of nitric oxide synthase stimulation and inhibition

Nitric oxide (NO) is synthesized from L-arginine by a family of enzymes known as the nitric oxide synthases (NOS). We have recently shown a NOS similar to constitutive brain NOS (bNOS) and endothelial NOS (ecNOS) to be present in spermatozoa. The aim of this study is to investigate NO production by human spermatozoa and the effects of stimulation and inhibition of NOS. This was carried out using the Iso-NO, an isolated NO meter and sensor, which provides rapid, accurate and direct measurements of NO. Semen samples with normozoospermic and asthenozoospermic profiles were prepared using a direct swim-up technique. Basal concentrations of NO and stimulated NO production were measured after exposure to the calcium ionophore (A23187; 0.01-10 microM) a potent activator of constitutive NOS. NO production in human spermatozoa was significantly increased by the addition of A23187 30 seconds after stimulation. Furthermore, this response was greatly diminished by pre-incubating the samples with competitive inhibitors of L-arginine, the substrate for NOS, before treatment with calcium ionophore. In the presence of N(G)-nitro-L-arginine methyl ester (L- NAME), N(G)-nitro-L-arginine (L-NA) or N(G)-methyl-L-arginine (L-NMMA; all at 10 microM), NO production was inhibited with a rank order of potency L-NAME > L-NMMA > L-NA which is in accordance with the inhibition of an endothelial type of constitutive NOS.      

Yoga lifestyle intervention reduces blood pressure in HIV‐infected adults with cardiovascular disease risk factors*

Objective

People living with HIV infection are at increased risk for developing cardiovascular disease (CVD). Safe and effective interventions for lowering CVD risk in HIV infection are high priorities. We conducted a prospective, randomized, controlled study to evaluate whether a yoga lifestyle intervention improves CVD risk factors, virological or immunological status, or quality of life (QOL) in HIV‐infected adults relative to standard of care treatment in a matched control group.

Methods

Sixty HIV‐infected adults with mild–moderate CVD risk were assigned to 20 weeks of supervised yoga practice or standard of care treatment. Baseline and week 20 measures were: 2‐h oral glucose tolerance test with insulin monitoring, body composition, fasting serum lipid/lipoprotein profile, resting blood pressures, CD4 T‐cell count and plasma HIV RNA, and the Medical Outcomes Study Short Form (SF)‐36 health‐related QOL inventory.

Results

Resting systolic and diastolic blood pressures improved more (P=0.04) in the yoga group (−5 ± 2 and −3 ± 1 mmHg, respectively) than in the standard of care group (+1 ± 2 and+2 ± 2 mmHg, respectively). However, there was no greater reduction in body weight, fat mass or proatherogenic lipids, or improvements in glucose tolerance or overall QOL after yoga. Immune and virological status was not adversely affected.

Conclusion

Among traditional lifestyle modifications, yoga is a low‐cost, simple to administer, nonpharmacological, popular behavioural intervention that can lower blood pressure in pre‐hypertensive HIV‐infected adults with mild–moderate CVD risk factors.

     

Compressive properties of commercially available polyurethane foams as mechanical models for osteoporotic human cancellous bone

Background  

Polyurethane (PU) foam is widely used as a model for cancellous bone. The higher density foams are used as standard biomechanical test materials, but none of the low density PU foams are universally accepted as models for osteoporotic (OP) bone. The aim of this study was to determine whether low density PU foam might be suitable for mimicking human OP cancellous bone.     

海南省HIV血清学检测报告

本文报告从海南省十一个HIV监测哨点采集的19653份血清标本中,发现了5例HIV抗体阳性者。这5例都是从泰国探亲回国时检测证实为Ⅰ型艾滋病病毒感染者的,表明我省近期内HIV传播的主要威胁途径为境外感染。