Psychological and physiological factors associated with tilt table testing for neurally mediated syncopal syndromes.

This study investigated psychological and physiological factors in two groups of patients who had tilt table testing for autonomic dysfunction. The first group of 61 patients completed assessments of depression, anxiety, and symptom effects on lifestyle. The 25 patients identified as tilt positive were younger (30.5 years) and had higher mean depression scores (7.6) compared to the tilt-negative response group (n = 36); the latter averaged 40 years of age and had mean depression scores of 4.6. These differences were statistically significant. Women testing tilt positive were significantly more depressed than tilt-negative women (P = 0.02). More severe depressive symptoms were associated with lower blood pressure (BP) (P < 0.05). A second group of 52 patients was monitored during tilt for BP, heart rate (HR), skin temperature (TEMP), skin conductance level (SCL), and forehead muscle tension (EMG). Twenty-seven tested positive and 23 were negative. There were statistically significant group differences in systolic BP and diastolic BP (P < 0.05). There was a significant interaction between tilt status (positive or negative) and time (P = 0.03) in HR. TEMP increased 2 degrees over time in both groups (P < 0.05). The decrease in SCL from 13.7 to 10.4 mu omega in the tilt-positive response group compared to the slight increase in the tilt-negative group was significantly different (P < 0.05). Identification of psychological factors correlated with BP and physiological changes that accompany decreases in BP in tilt-positive response patients could guide management of patients with autonomic dysfunction.

Asthma severity, psychophysiological indicators of arousal, and immune function in asthma patients undergoing biofeedback-assisted relaxation.

Asthma is characterized by airway hyper-responsiveness, inflammation, and reversible obstruction. Respiratory tract infection, allergies, air pollution, and psychosocial factors impact the severity and frequency of asthma symptoms. Pharmacotherapy and self-care are the major components in the management of asthma, but behavioral interventions also have the potential to affect asthma morbidity. We conducted a small, randomized controlled study, examining the effects of biofeedback-assisted relaxation in 16 nonsmokers with nonsteroid-dependent mild asthma. Data were collected on asthma symptoms, pulmonary function, indicators of arousal, and cellular immune factors. The trained group evidenced a decrease in forehead muscle tension in comparison to the controls, but no changes in peripheral skin temperature. Decreases in asthma severity and bronchodilator medication usage for the experimental group were observed. Pulmonary function testing revealed a significant difference between groups in FEV1/FVC at posttest, with the E group having a higher ratio than the controls. The cellular immune data showed no significant group differences in total white blood cell or lymphocyte counts, but decreases over time were observed. Significant differences were observed in the numbers of neutrophils and basophils in the trained group compared to controls, which supports the concept of decreased inflammation. Results of delayed-type hypersensitivity skin testing suggested enhanced function, but they were not conclusive. These findings, though limited by size of population, suggest a positive effect of biofeedback-assisted relaxation in young, nonsteroid-dependent asthmatics. The mechanisms underlying linkages between psychological, behavioral, and immune responses in asthma require further study.

Receptor-mediated internalization of insulin. Potential role of pp120/HA4, a substrate of the insulin receptor kinase.

pp120/HA4 is a hepatocyte membrane glycoprotein phosphorylated by the insulin receptor tyrosine kinase. In this study, we have investigated the role of pp120/HA4 in insulin action. Transfection of antisense pp120/HA4 cDNA in H35 hepatoma cells resulted in inhibition of pp120/HA4 expression and was associated with a 2-3-fold decrease in the rate of insulin internalization. Furthermore, insulin internalization in NIH 3T3 fibroblasts co-transfected with insulin receptors and pp120/HA4 was increased 2-fold compared with cells expressing insulin receptors alone. In contrast, no effect on internalization was observed in cells overexpressing a naturally occurring splice variant of pp120/HA4 that lacks the phosphorylation sites in the intracellular domain. Insulin internalization was also unaffected in cells expressing three site-directed mutants of pp120/HA4 in which the sites of phosphorylation by the insulin receptor kinase had been removed (Y488F, Y488F/Y513F, and S503A). Our data suggest that pp120/HA4 is part of a complex of proteins required for receptor-mediated internalization of insulin. It is possible that this function is regulated by insulin-induced phosphorylation of the intracellular domain of pp120/HA4.