The T30 value could be a specific index for vagally mediated heart rate recovery. Vagally mediated heart rate recovery after exercise is accelerated in well trained athletes but blunted in patients with chronic heart failure.

To study the effects of aging and gender, circadian profiles of heart rate variability were evaluated for 105 healthy volunteers by frequency domain analysis of a Holter electrocardiogram record. The low-frequency (LF) component representing cardiac beta-adrenergic function showed high values for the 0800-1200 period in male subjects and the 1200-2400 period in female subjects. The high-frequency (HF) component representing parasympathetic function showed a peak for the 0000-0600 period in both male and female subjects independent of age. Male subjects showed significantly higher %LF [LF/(LF + HF) x 100] than female subjects. LF showed consistently highly significant correlation with age. These basic findings can help elucidate the diurnal profile of cardiac nerve function and how it is affected by aging and sex difference.

Chemical indices, especially diradical character, are utilised to examine the functions and reactivity of stable radical species. In the present study, we formulated an approximation to estimate chemical indices using...

A new cardioselective ,81-adrenoceptor partial agonist, xamoterol, has been developed for the treatment of heart failure, especially that associated with ischemic heart disease. To investigate the hemodynamic effect of xamoterol in relation to sympathetic nervous activity, hemodynamic variables and plasma norepinephrine (NE) levels were measured at rest and during three graded bicycle exercise tests before and after a single intravenous dose of 0.15 mg/kg xamoterol in 10 patients with mild-to-moderate left ventricular dysfunction. Plasma NE increased with increasing grade of exercise and a linear correlation between plasma NE and heart rate was observed at four time points (at rest and three exercise levels) before and after xamoterol. After administration of xamoterol, the slope of the regression line of plasma NE-heart rate relation was significantly less steep than that before drug. Predose and postdose regression lines crossed at 440 pg/ml of plasma NE. Similar effects were observed on the plasma NE-cardiac index and plasma NE-systolic blood pressure relations (regression lines crossed at 380 and 530 pg/ml of plasma NE, respectively). Thus, xamoterol had a dual agonistantagonist effect in relation to plasma NE, and the crossover point lay approximately between 400 pg/ml and 500 pg/ml. This level of plasma NE was achieved at a low exercise level and at a heart rate of about 100 beats/min. These results indicate that xamoterol has intrinsic sympathomimetic activity comparable to relatively low sympathetic activity (400 to 500 pg/ml of plasma NE) and therefore acts as a,81-agonist when sympathetic nervous activity is below this level and as an antagonist when sympathetic activity is above this level.

Improvement of glycosylation is one of the most important topics in the industrial production of therapeutic antibodies. We have focused on terminal sialylation with alpha-2,6 linkage, which is crucial for anti-inflammatory activity. In the present study, we have successfully cloned cDNA of beta-galactosyl alpha-2,6 sialyltransferase (ST6Gal I) derived from Chinese hamster ovary (CHO) cells regardless of reports that stated this was not endogenously expressed in CHO cells. After expressing cloned ST6Gal I in Escherichia coli, the transferase activity was confirmed by HPLC and lectin binding assay. Then, we applied ST6Gal I to alpha-2,6 sialylation of the recombinant antibody; the ST6Gal I expression vector was transfected into the CHO cell line producing a bispecific antibody. The N-glycosylation pattern of the antibody was estimated by HPLC and sialidase digestion. About 70% of the total N-linked oligosaccharide was alpha-2,6 sialylated in the transfected cell line whereas no sialylation was observed in the non-transfected cell line. The improvement of sialylation would be of practical importance for the industrial production of therapeutic antibodies.