Abnormal plasma monoamine metabolism in schizophrenia and its correlation with clinical responses to risperidone treatment.

Abnormalities in plasma monoamine metabolism reflect partly the illness of schizophrenia and sometimes the symptoms. Such studies have been repeatedly reported but have rarely taken both metabolites and parent amines or inter-amine activity ratios into account. In this study, the monoamines, their metabolites, turnovers and between-metabolite ratios in plasma were measured longitudinally in 32 schizophrenic patients treated with risperidone for 6 weeks, to examine possible biochemical alterations in schizophrenia, and to examine the association between treatment responses and psychopathology assessed according to the Positive and Negative Syndrome Scale (PANSS). The results showed lower level of plasma 3,4-dihydroxyphenylacetic acid (DOPAC) in relapsed versus first-episode schizophrenic patients, higher norepinephrine (NE) turnover rate (TR) in undifferentiated in comparison to paranoid schizophrenic patients and relatively higher metabolic activity of dopamine (DA) to serotonin (5-HT) in first-episode versus relapsed schizophrenic patients. Risperidone treatment induced a decrement of plasma DA levels and increments of plasma DOPAC and DA TR in the total group of schizophrenic patients. The turnover rate of 5-HT was was reduced in undifferentiated and relapsed subgroups of schizophrenic patients. The linkages between 5-HT TR, DA/NE relative activity and clinical symptomatology were also identified. These findings are consistent with an involvement of these systems in the pathogenesis of schizophrenia as well as in the responses to treatment, and the usefulness of certain biochemical indices as markers for subgrouping.

Attenuation of autonomic nervous system functions in hypertensive patients at rest and during orthostatic stimulation.

The effect of age on autonomic nervous system was assessed at rest and while standing using systolic blood pressure (SBP) and diastolic blood pressure (DBP), heart rate, and power spectral analysis of the time duration between 2 consecutive R waves of an electrocardiogram (RR) interval variability, as well as on plasma norepinephrine and epinephrine levels in mild to moderate hypertensive patients (DBP, 90-110 mm Hg). Patients younger than 60 years (n=57) and older than 60 years (n=32), were evaluated after a 3- to 4-week placebo period. Plasma catecholamines were measured in the supine position at rest and after 10 minutes of standing. Power spectral analysis of the RR interval variability was performed in each condition using the high-frequency (HF) band (0.15-0.4 Hz) as an index of parasympathetic activity and the low-frequency (LF) band (0.05-0.15 Hz) and LF-HF ratio to estimate sympathetic activity. The total power was calculated as the sum of LF and HF power. supine SBP was significantly higher in older patients (P<.05). SBP and DBP increased significantly only in younger patients during standing (P<.05), while the changes were smaller and nonsignificantly lower in older patients. HR was similar in both groups at rest and increased similarly during standing. Norepinephrine and epinephrine levels were similar at rest and increased similarly in both groups of patients during standing. At rest, lower LF and HF components were observed in older patients. The LF component increased less and the HF component decreased less in older patients during standing. A lower sympathetic and parasympathetic basal cardiac tone was observed at rest in older hypertensive patients. Moreover, reduced hemodynamic and sympathetic responses to standing as assessed by SBP, DBP, and the LF component of HR variability were observed in older hypertensives in the presence of a normal catecholamine response. These observations could reflect a decreased sensitivity of cardiac beta-adrenoceptors with aging.

Neurohumoral activation as a link to systemic manifestations of chronic lung disease.

COPD is a major cause of death and disability worldwide. Treatment of COPD improves lung function but is unlikely to slow the steady downhill course of the disease or reduce mortality. In COPD, numerous abnormalities can be found outside the lung. These include systemic inflammation, cachexia, and skeletal muscle dysfunction. Thus, COPD has been called a systemic disease. Convincing data demonstrate that COPD causes neurohumoral activation. By precedents derived from chronic heart failure and other diseases characterized by neurohumoral activation, we propose that the negative consequences of neurohumoral activation, namely inflammation, cachexia, effects on ventilation, and skeletal muscle dysfunction, give rise to a self-perpetuating cycle that contributes to the pathogenesis of COPD, and which may involve respiratory muscle dysfunction as well as systemic inflammation. This concept may further help explain the increased cardiovascular morbidity and mortality in COPD patients. Currently, little is known about the effect of treatments directed at neurohumoral activation and COPD. As this aspect of COPD becomes better understood, new insights may direct novel therapeutic approaches.

Is hormonal activation during exercise useful for risk stratification in patients with moderate congestive heart failure?

BACKGROUND: We previously demonstrated that A-type natriuretic peptide (ANP) at peak exercise was an independent predictor of cardiac survival. No data are available concerning the predictive value of B-type natriuretic peptide (BNP) at peak exercise. METHODS: One hundred and fifty consecutive stable patients with moderate congestive heart failure (CHF) underwent echocardiography and a cardiopulmonary exercise test. Blood samples were drawn at rest and at peak exercise for the determination of plasma levels of ANP, BNP, and norepinephrine. RESULTS: Exercise significantly increased plasma values of ANP, BNP, and norepinephrine. After a median follow-up period of 1171 days, there were 35 cardiac related deaths. Mortality rates at 1 and 2 years were 4% and 8%, respectively. Independent predictors of cardiac survival were percent of maximal predicted oxygen consumption (RR = 4.8 [2.1-11], P =.002), BNP at rest (RR = 2.5 [1.2-5.6], P =.01), and left atrial diameter (RR = 2.8 [1.2-6.5], P =.02). CONCLUSIONS: In patients with stable, moderate CHF, plasma levels of ANP, BNP, and norepinephrine measured at peak exercise did not improve risk stratification. However, in addition to percent of maximal predicted oxygen consumption and left atrial diameter, plasma level of BNP at rest was an independent predictor of survival in CHF patients with low risk of cardiac events.

Lateralization in autonomic dysfunction in ischemic stroke involving the insular cortex.

Autonomic nervous system dysfunction is a common complication of ischemic stroke. Clinical and experimental data indicate hemispheric lateralization in the control of autonomic activity. The insular cortex has also been shown to play a crucial role in the central autonomic network. The aim of this study was to assess cardio-autonomic dysfunction in patients with ischemic insular versus non-insular cortex infarction, and to demonstrate a possible lateralization in autonomic activity mediated by the insular cortex. Sympathetic function was prospectively assessed by determining plasma norepinephrine and epinephrine in 15 patients with left-hemisphere (LH; four insular infarction), and 14 with right-hemisphere (RH) middle cerebral artery (MCA) stroke (five insular infarction). Systolic and diastolic blood pressure and heart rate were recorded during the first 5 days after stroke. Sympathetic activity was significantly higher in insular than in non-insular infarction (p < 0.05) with concomitantly elevated cardiovascular parameters in insular stroke patients. The pathological activation of the sympathetic nervous system was most excessive in RH-stroke involving the insular cortex (p < 0.05). Our data indicate a hemispheric lateralization in autonomic activity which is mediated by the right-sided insular cortex. Patients with RH stroke involving the insular cortex are most susceptible to develop cardio-autonomic dysfunction.

[Further study on the indexes of auxiliary laboratory diagnosis in the syndrome of hyperactivity of liver-yang].

The indexes of auxiliary laboratory diagnosis, including plasma norepinephine (NE) levels, plasma epinephrine (E) levels, mean blood flow velocity of the middle cerebral artery (MCA-Vm) and systolic blood flow velocity of the middle cerebral artery (MCA-Vs), were observed in patients with the syndrome of hyperactivity liver-yang. The results indicated that the levels of the 4 indexes were significantly higher in the patients with the syndrome of hyperactivity liver-yang than those in the controls. In hypertension patients with the syndrome of hyperactivity liver-yang, there was a positive correlation between symptomatic scores of the syndrome of hyperactivity liver-yang and diastolic pressure (Pd), plasma NE and E levels. The symptoms ameliorated, and the levels of the 4 indexes decreased correspondingly in 3 weeks after the treatment of Qianyangfang (a traditional Chinese herb).

Comprehensive local muscle training increases aerobic working capacity and quality of life and decreases neurohormonal activation in patients with chronic heart failure.

BACKGROUND: Beneficial training outcomes have been reported in patients with chronic heart failure (CHF) following leg exercise training. However, data from more comprehensive training programs are limited. The aim of this study was to test the hypothesis that exercise training applying the concept of comprehensive local muscle training can improve aerobic and functional working capacity as well as quality of life in patients with CHF. METHODS: Twenty-four men and women [age 63+/-9 years (mean+/-S.D.)] with stable, moderate chronic heart failure (left ventricular ejection fraction 30+/-10%), were investigated in a randomized controlled study with a training group of 16 patients and a control group of 8 patients. The training was performed as an aerobic resistance training by activating all the main muscle groups, one at a time. The patients exercised for 1 h, three times per week for 8 weeks. RESULTS: Patient groups did not differ at baseline. Peak oxygen uptake (8%, P<0.03), the distance walked in a 6-min walking test (11%, P<0.002), the health-related quality of life (P<0.001) and plasma norepinephrine levels at rest (32%, P<0.003) and at submaximal intensities (P<0.03) improved after training. No changes were found in the control group, except for decreased peak oxygen uptake (P<0.02) and quality of life scores (P<0.03). CONCLUSIONS: Since comprehensive physical training activating a minor muscle mass at a time markedly improves exercise capacity and quality of life and reduces catecholamine levels, it can be recommended for the rehabilitation of patients with CHF under supervision of a physical therapist.

Endocrinological and biophysical responses to further reduction in oxygenation following sustained hypoxemia in fetal goats.

OBJECTIVE: The purpose of this study was to determine fetal endocrinological and biophysical responses to the further reduction in oxygenation following prolonged nonacidemic hypoxemia in fetal goats. METHODS: Seven further hypoxic experiments were performed after prolonged (24-h) nonacidemic hypoxemia, caused by an infusion of nitrogen into the maternal trachea and by reducing uterine arterial blood flow in four chronically instrumented goat fetuses at 123-131 days' gestation. We measured arginine vasopressin, adrenocorticotropic hormone, cortisol, and catecholamines as endocrinological parameters. Fetal heart rate, fetal blood pressure, and fetal breathing movement were observed as biophysical parameters. RESULTS: Fetal arterial pO2 was significantly decreased from 27.0 +/- 1.2 mmHg (control) to 18.0 +/- 0.7 mmHg and 11.3 +/- 1.3 mmHg at the end of the prolonged hypoxemia and the further hypoxia, respectively. The further hypoxia induced reductions in fetal heart rate, increases in fetal blood pressure, and a series of gasping. Arginine vasopressin and catecholamines were elevated significantly by the further hypoxia. Although adrenocorticotropic hormone and cortisol were increasingly elevated, they did not reach a significant level. CONCLUSIONS: Some specific fetal responses-excessive elevations of fetal catecholamines, arginine vasopressin, accompanied with fetal gasping-were observed during further severe hypoxia.

Optimal collection and storage conditions for catecholamine measurements in human plasma and urine.

Improvements in methodologies for measuring concentrations of catecholamines (CA) have led to an increasing use of these compounds as markers in the screening of patients and in long-term clinical trials. Because of the associated logistical problems, we have investigated the unresolved question of optimal conditions for sample preparation and for storage of plasma and urine samples. Results show that blood should be centrifuged within 1 h after collection; the use of a refrigerated centrifuge is not necessary. Once plasma is prepared, CA are stable for 1 day at 20 degrees C, 2 days at 4 degrees C, 1 month at -20 degrees C (or 6 months with added glutathione), and up to 1 year at -70 degrees C. CA are stable at 4 degrees C for 1 month in unpreserved urine and for 4 months in urine preserved with EDTA and sodium metabisulfite. In acidified urine, CA were nearly unchanged after 1 year at 4 and -20 degrees C.

Location of vascular alpha 2-adrenoceptors in man.

To determine whether vascular postsynaptic alpha 2-adrenoceptors are innervated by sympathetic nerves in man, normal volunteers were infused for 90 min with angiotensin II (A II) and the alpha 2-adrenoceptor agonist alpha-methylnoradrenaline (MNA) in a double-blind cross-over study. Whilst systolic blood pressure returned to baseline within 5 min of terminating the A II infusion it remained elevated 40 min after stopping MNA. The prolongation of the pressor response to MNA, a substrate for neuronal uptake, was probably due to activation of alpha 2-adrenoceptors by MNA re-released from contiguous sympathetic nerve endings. The proximity of alpha 2-adrenoceptors to sympathetic nerve terminals suggests that they could contribute to blood pressure regulation in man.