Doppler echocardiographic assessment of left ventricular diastolic function in chronic hypoxic rats

Little information is available on the mechanism of diastolic left ventricular (LV) dysfunction in patients with chronic respiratory disease complicated by hypoxia. The purpose of this study was to investigate how chronic hypoxia impairs LV diastolic function in an hypoxic animal model. Thirty-six male Wistar rats 8 weeks old were assigned to normoxia (N), chronic hypoxia (CH), and re-normoxia (RN) groups, 12 rats per group. The N group rats were kept in ambient air for 8 weeks, while the CH group was kept hypoxic for 8 weeks. After 8 weeks of hypoxia the RN group rats were kept for a further 8 weeks in ambient air. LV systolic and diastolic functions, as well as right ventricular (RV) function, were analyzed using Doppler echocardiography;we also measured the hematocrit, and weighed the LV and RV. Hematocrit, RV weight/body weight, and RV weight/LV weight were higher in the CH group than in the other 2 groups. However, most of these parameters returned to normoxia levels after re-normoxia. In the CH group, LV dimension and area were smaller than in the other 2 groups. LV systolic function was preserved in all groups;however, in the CH group, mitral flow showed a restrictive pattern, while pulmonary flow demonstrated a pulmonary hypertensive pattern with prolonged RV ejection time. In conclusion, chronic hypoxia induced pulmonary hypertension and RV hypertrophy. Although LV systolic function was preserved, diastolic function was impaired in hypoxia. Ventricular interaction may impair LV diastolic function.</p

Characterization of a novel monoclonal antibody that senses nitric oxide-dependent activation of soluble guanylate cyclase

AbstractTwo monoclonal antibodies (mAbs) against bovine lung soluble guanylate cyclase (sGC) were prepared and characterized. mAb 3221 recognized both the α- and β-subunits of sGC and had greater binding affinity to the enzyme in the presence of NO. mAb 28131 recognized only the β-subunit and its affinity did not change with NO. Neither mAb cross-reacted with particulate GC. Cultured Purkinje cells from rats were treated with S-nitroso-N-acetylpenicillamine, an NO donor, and examined by immunocytochemical methods. The immunoreactivity associated with mAb 3221 increased with the cGMP content in a crude extract of cerebellum and the NO2 generated in the culture medium increased