Effect of the microtubule-associated protein tau on dynamics of single-headed motor proteins KIF1A.

Intracellular transport based on molecular motors and its regulation are crucial to the functioning of cells. Filamentary tracks of the cells are abundantly decorated with nonmotile microtubule-associated proteins, such as tau. Motivated by experiments on kinesin-tau interactions [Dixit et al., Science 319, 1086 (2008)] we developed a stochastic model of interacting single-headed motor proteins KIF1A that also takes into account the interactions between motor proteins and tau molecules. Our model reproduces experimental observations and predicts significant effects of tau on bound time and run length which suggest an important role of tau in regulation of kinesin-based transport.

Shock detection in dynamics of single-headed motor proteins KIF1A via Jensen-Shannon divergence.

Information theoretic quantities are useful tools to characterize symbolic sequences. In this paper, we use the Jensen-Shannon divergence to study symbolic binary sequences that represent the stationary state of a lattice-gas model describing the traffic of monomeric kinesin KIF1A. More specifically, the constructed binary sequences represent the state of a microtubule protofilament at different adenosine triphosphate (ATP) and KIF1A motor concentrations in the cytosol. The model presents some stationary regimes with phase coexistence. By using the Jensen-Shannon divergence, we develop a method of analysis that allows us to identify cases in which phase coexistence occurs and, for these cases, to locate the position of the interphase that separates the regions with different phase.

Self-monitoring and blood pressure.

The association between self-monitoring (regulation and control of nonverbal and expressive behavior) and blood pressure was examined in a field study of 594 municipal employees. For persons not taking antihypertensive medication, the Acting/Extraversion scale was mildly positively associated with resting blood pressure among whites in general, blue collar, clerical, and professional groups. Stronger positive correlations were obtained for attorneys and customer service representatives. These results are contrasted with slightly negative associations for blacks in general, first-level supervisors, and a group of previously studied union stewards. An interactive effect was also obtained between Acting/Extraversion and relative participation in work versus nonwork groups and activities; Acting/Extraversion and systolic pressure were inversely related for employees more active in extrawork groups but not related among other workers. Differential consequences of greater or lesser interpersonal involvement and emotional regulation in different jobs are considered.

Blood pressure of male municipal employees: effects of job status and worksite.

Repeated measurements of resting blood pressure and heart rate were obtained at the worksite for a sample of 441 male municipal employees ranging widely in age (M = 41 yr.), job level, and education. As a result of unusually high diastolic values (M = 91), over-all uncontrolled hypertension rates were very high (33% of the men exceeding 160 systolic or 95 diastolic including those on medication). Higher rates were obtained for blue collar as opposed to white collar employees and for those plant workers in the Division of Water as opposed to Sewerage and Drainage. Net of age, weight, smoking, education, and anti-hypertensive medication use, higher systolic and diastolic mean values were obtained for supervisors who were primarily employed as foremen and clerical personnel. Inter-plant differences in blood pressure were also found for primarily blue collar Sewers and Drains employees, though whites' and blacks' values were nearly identical. Comparisons with national blood pressure data indicate significant effects for level of job and education which again disfavored supervisors and clerical employees and in addition men who had more education. Whites' and blacks' blood pressures deviated significantly from expected values, the differences favoring blacks. Social psychological mechanisms which may mediate these effects are discussed.

Psychological correlates of blood pressure: a closer examination of hostility, anxiety, and engagement.

Recent studies by other investigators have shown that hypertensives are more hostile and anxious than normotensives. The first part of this study examined the relationship between blood pressure measured daily over a one-week period and responses to a series of questions specifically developed to distinguish hypertensives from normotensives. Responses from this sample of undergraduates did not distinguish those with high blood pressure from those with normal values. Mean resting blood pressure was related to hostility and anxiety factor scores among males but not among females. Our second study used a sample of municipal employees and examined blood pressure as a function of comparable anxiety and hostility scores as well as a trait measure of overall "engagement-involvement." More highly engaged workers were no different in anxiety or hostility than less engaged workers. There was some evidence of more variable blood pressure for the former group. It is suggested that stable personality traits such as hostility and anxiety may both precede and follow the diagnosis of blood pressure. For nurses it is important to assess the patient's general psychological profile as well as his of her emotional state at the time of measurement. Repeated blood pressure readings are recommended especially for highly engaged individuals.

Blood pressure, stress, and mental health.

Evidence of the interaction between psychological factors and blood pressure is reviewed with a focus on stressful events and mental health. While the hypertensive personality remains an elusive and perhaps fictional entity, and indices of psychological distress, psychopathology, or poor adjustment do not correlate highly with blood pressure or hypertension, environment stressors such as the threat of unemployment and job pressures adversely affect blood pressure and mental health across groups of individuals. Recent studies suggest that the diagnosis of hypertension may elicit clinically significant psychological distress and anxiety. Adverse reactions to antihypertensive medication may interact with and exacerbate pre-existing distress. Implications for nurses dealing with hypertensive patients are discussed.

Engagement-involvement and blood pressure change: a methodological inquiry.

In a study that examined further Singer's model of engagement-involvement in a community nursing setting, 31 black inner-city women conversed informally with a nurse while their blood pressure was monitored at two-minute intervals using a Hoffman-LaRoche Arteriosonde. Type A (coronary-prone) and hypertensive subjects were judged to not display greater engagement than type B and normotensive subjects, respectively. Within-subject correlations between observers' ratings of engagement and blood pressure showed substantial differences across subjects. Nevertheless, for correlations based on engagement judgments corresponding to the minute immediately preceding the blood pressure determination the mean within-subject values ranged from .14 to .32 (mean = .20) and were all significantly different from zero. Attention is directed to the need for refining the criteria used for judging engagement and to identifying patients for whom increased engagement may invalidate blood pressure measurements in a clinical setting.

The type A behavior pattern: a critical assessment.

Research on the Type A (coronary-prone)behavior pattern has proliferated at a rapid rate in recent years. With the cardiovascular risk value of Type A behavior well established, many studies have focused on reliability, validity, and other essentially psychological and psychometric issues. These studies are evaluated, along with the fundamental assumptions underlying the construct. Further research is suggested which examines the comparative predictive validity of Type A behavior and its defining criteria across diverse populations and the interaction of stress and behavior pattern.

Type A (coronary-prone) behavior and transient blood pressure change.

A study was conducted to delineate further the physiological mechanisms underlying the type A behavior pattern's influence on coronary heart disease. It was suggested that while chronically elevated blood pressure is apparently not associated with overall A--B distinctions (at least not for males), acting in a type A fashion may be accompanied by temporary increases in blood pressure. Changes in the speech characteristics of 33 black inner-city women during the A--B interview and subsequent unstructured dialogue were analyzed at one-minute intervals and correlated with concomitant blood pressure measurements. Differences in the speech characteristics of women classified type A as opposed to B were consistent with recent studies of white males (e.g., type As spoke significantly faster than type Bs). Further, within-subject blood pressure elevations were significantly associated with louder/more explosive, longer speech episodes. Additional research is urged which examines biochemical and physiological changes as a function of type A behavior considered as a transient state as well as a relatively enduring trait.

The type A (coronary-prone) behavior pattern, aging, and mortality.

Young and middle-aged persons displaying the Type A (coronary-prone) behavior pattern have been shown repeatedly to be at substantially increased risk of coronary heart disease. A review of recent empirical research regarding adaptability and survival among the elderly suggests the hypothesis that the clinical significance of Type A behavior may shift radically in old age. Thus, compared to Type B (not coronary-prone) subjects. Type As may be at lesser rather than greater risk of impairment and death.

An attributional approach to psychotherapy with the aged.

The continued growth of the number of aged persons potentially requiring psychotherapeutic service should be met with a concomitant increase in relevant theory and research. An attribution theory approach to individual psychotherapy with the aged is suggested insofar as it: 1) is explicitly responsive to the possible negative consequences of the old person's diminished use of social consensus to validate the interpretation of behavioral events, 2) is relatively concrete in terms of implementation, and 3) may be used on a short-term basis.

Individual psychotherapy with the aged: a selective review.

While elderly individuals are still markedly underrepresented in facilities providing outpatient psychological services, clinical interest in individual psychotherapeutic intervention with the aged mentally ill has gradually risen during the past several decades. A broad review of the literature suggests that published descriptions of such interventions have generally been global and vague and that research reports, while collectively pointing to the feasibility of individual psychotherapy, have been infrequent and methodologically weak. In view of the rising numbers of elderly persons potentially requiring psychological services and a probable decrease in the mutual avoidance of therapists and the aged, the need for further theoretical development and empirical research is indicated.

Type A behavior pattern and hypertension among inner-city black women.

Inner-city Black women were administered Rosenman and Friedman's A-B interview and invited to discuss stress experiences and traditional coronary heart disease risk factors while their blood pressure was monitored at two-minute intervals. Results revealed the essential reliability of the A-B classification for the sample and demonstrated a general congruence with type A behaviors reported in previous (mostly white male) samples. While type A Black women were not significantly more likely to be hypertensive than type B women, analyses of the intrasubject blood pressure variability revealed an interaction between A-B and hypertensive-normotensive status. Consistent with earlier findings, hypertensives were more variable than normotensives, but this was true only for type Bs; type As were intermediate and not differentiated in their variability. This finding calls attention to the possible adaptive function of type A behavior among stress inner-city Black females and raises the question of whether Rosenman and Friedman's personality theory might be objectionably simplistic.