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Biomedical subjects

Howard S Friedman

Publications and source records attributed to Howard S Friedman.

10 recordsLinked to original sources
PubMed2006

Determinants of the total cosine of the spatial angle between the QRS complex and the T wave (TCRT): implications for distinguishing primary from secondary T-wave abnormalities.

BACKGROUND: Contrary to intuitive expectations and dissimilar from that which occurs in the atria, left ventricular (LV) depolarization and repolarization proceed in opposite directions, creating a concordance of the spatial QRS complex and T-wave angles (QRS-T). By defining the determinants of QRS-T, it might be possible to distinguish a primary (caused by an abnormality of repolarization) from a secondary (caused by a delay in ventricular depolarization) T-wave abnormality. METHODS AND RESULTS: From a near-consecutive series of 154 patients (age, 60 +/- 16 years; 81 females) in sinus rhythm, Doppler echocardiographic and 12-lead electrocardiogram (ECG) findings were related to the total cosine of the angle subtended by the spatial QRS complex and T wave (TCRT). Using the QRS complex and T-wave angles in the frontal and horizontal planes, TCRT was obtained from the table cited in the article of Helm and Fowler (Am Heart J 1953;45:835). TCRT correlated negatively with age, QRS duration (QRS), interventricular septal thickness (IVS) and posterior wall thickness, LV mass, LV cross-sectional area (CSA), LV relative wall thickness (RWT), left atrial dimension, and atrial velocity time integral (all, P < .001), but it was not related to LV diastolic dimension or systolic function. In multivariate analyses of the entire cohort or of patients without a left bundle branch block, QRS, CSA, RWT, and atrial velocity time integral emerged as independent variables (all, P < .001). When patients with right bundle branch block were also excluded, IVS, instead of CSA and RWT, was significant (P < .001). Overall, TCRT distinguished normal patients from those with heart disease, and patients with diabetes mellitus and hypertension from those not having these conditions. However, residuals of regression, TCRT = (-1.6IVS [cm]) + (-0.01QRS [milliseconds]) + 3, distinguished patients with coronary disease, but not other disorders, from normals, and diabetics, but not patients with hypertension or hyperlipidemia, from those not having these conditions (the regression having adjusted for secondary QRS-T discordance). CONCLUSIONS: The determinants of TCRT can be quantified and expressed as a regression that may be used to distinguish primary from secondary T-wave abnormalities.

Arrhythmias, Cardiac↗
PubMed2006

Health status and the five-factor personality traits in a nationally representative sample.

The authors' objective was to determine the association between the 'big-five' personality traits and mental and physical disorders among adults in the United States. The Midlife Development in the United States Survey, a nationally representative sample of 3032 adults ages 25-74, was used to determine the association between the five-factor traits of personality and common mental and physical disorders. Findings are consistent with and extend previous results showing that conscientiousness is associated with significantly reduced likelihood of a wide range of mental and physical disorders among adults in the general population, and inversely that neuroticism is associated with increased rates. Among adults with physical illnesses, associations were found between personality and likelihood of physical limitations, especially conscientiousness. These findings provide a framework upon which research on complex causal processes may proceed. Thus future research attention might profitably be directed to conscientiousness-relevant processes, such as adherence to health and treatment recommendations and internalization of healthy societal norms for sensible health-related behavior.

Adult↗
PubMed2006

Moxifloxacin versus levofloxacin for treatment of acute rhinosinusitis: a retrospective database analysis of treatment duration, outcomes, and charges.

OBJECTIVE: Antibiotics are clinically indicated for acute bacterial rhinosinusitis, but they may be prescribed inappropriately. This retrospective study examined how labeled recommendations for duration of moxifloxacin and levofloxacin treatment of acute bacterial rhinosinusitis compare with real-world practice, and compared the failure and recurrence rates, and associated charges. METHODS AND MAIN OUTCOME MEASURES: The PharMetrics Patient-Centric claims database was searched over a 3-year period for episodes of acute rhinosinusitis treated within 5 days with moxifloxacin or levofloxacin. The duration of antibiotic treatment prescribed was compared with the labeled recommendation. Failure rates (a second antibiotic claim to treat acute rhinosinusitis within 30 days of the first claim), recurrence rates (subsequent antibiotic claims to treat any rhinosinusitis more than 30 days after the original or second [in the case of failure] claim), and treatment charges from the perspective of the payer (health insurer) were also compared using multivariate analysis. RESULTS: The initial duration prescribed of moxifloxacin was shorter than for levofloxacin (-1.65 days, p < 0.0001), reflecting the shorter labeled recommendation (10 days versus 10-14 days). The durations of monotherapy (-2.06 days, p < 0.0001) and of all antibiotic treatment (-1.97 days, p < 0.0001) were also significantly shorter for episodes treated initially with moxifloxacin. The odds ratio for treatment failure (0.718; 95% confidence interval = 0.598-0.863; p = 0.0004) and the hazard ratio for recurrence (0.652; p = 0.0005) were both significantly lower for moxifloxacin than for levofloxacin, and resulted in lower total treatment charges (-$37.94 +/- 13.65; p = 0.0055). CONCLUSION: The shorter treatment durations seen for moxifloxacin in this database of real-world care reflect the label-recommended duration for acute rhinosinusitis. Despite this shorter duration of therapy, moxifloxacin resulted in better outcomes than levofloxacin in terms of the risk of treatment failure and recurrence. In addition, the total charges were lower for patients treated with moxifloxacin.

Acute Disease↗
PubMed2005

Longevity following the experience of parental divorce.

An archival prospective design was used to study mediating and moderating variables for the association between parental divorce and increased mortality risk, using a sub-group (n = 1183) of individuals from the US Terman Life Cycle Study covering the period 1921-2000. In childhood, both socioeconomic status (SES) and family psychosocial environment were related to parental divorce but did little to explain its effects. The higher mortality risk associated with experiencing parental divorce was ameliorated among individuals (especially men) who achieved a sense of personal satisfaction by mid-life. Behaviorally, smoking was the strongest mediator of the divorce-mortality link. This study extends previous work on the long-term effects of parental divorce and reveals some reasons why the stress of parental divorce in childhood need not necessarily lead to negative later-life outcomes.

Child↗
PubMed2004

Heart rate variability in atrial fibrillation related to left atrial size.

The purpose of this investigation was to determine whether heart rate variability (HRV) in atrial fibrillation (AF) can be related to any echocardiographic-derived measurements of cardiac dimensions or function. AF is characterized by marked HRV. Although HRV in normal sinus rhythm has been studied and shown to have important clinical implications, there have been relatively few published reports dealing with the phenomenon in AF. This study examines HRV in AF taking into account the influence of heart rate. HRV measurements were obtained in 38 patients with persistent AF who had undergone 24-hour ambulatory electrocardiographic monitoring. Taking into account a strong heart rate dependence of the HRV measurements, regressions were calculated. The relations were then re-examined using the differences (diff) in HRV from the expected for the average RR intervals. No significant correlations were found between unadjusted HRV measurements and any clinical features or echocardiographic variables. However, taking into account heart rate relations, with negative HRVdiff signifying less HRV than expected, reduced HRV correlated with increasing left atrial and left ventricular dimensions. On multivariate regression analysis, left atrial dimension emerged as an independent determinant of HRV. Also, HRV was greater in patients with lone AF than in those with cardiac disorders. HRV in AF is highly rate dependent. Unless this influence is taken into account, important relations may be obscured. When HRVdiff are related to echocardiographic measurements, increasing left atrial dimensions correlate with less HRV.

Aged↗
PubMed2003

The coding of uniform colour figures in monkey visual cortex.

Psychophysical studies indicate that perception of the colour and brightness of a surface depends on neural signals evoked by the borders of the surface rather than its interior. The visual cortex emphasizes contrast borders, but it is unclear whether colour surface signals also exist, whether colour border signals are orientation selective or mainly non-oriented, and whether cortical processing tends to separate colour and form information. To address these questions we examined the representation of uniform colour figures by recording single neuron activity from areas V1 and V2 in alert macaque monkeys during behaviourally induced fixation. Three aspects of coding were quantified: colour, orientation and edge selectivity. The occurrence of colour selectivity was not correlated with orientation or edge selectivity. The fraction of colour-selective cells was the same (64 % in layers 2 and 3 of V1, 45 % in V2) for oriented and non-oriented cells, and for edge-selective and surface-responsive cells. Oriented cells were often highly selective in colour space, and about 40 % of them were selective for edge polarity or border ownership. Thus, contrary to the idea of feature maps, colour, orientation and edge polarity are multiplexed in cortical signals. The results from V2 were similar to those from upper-layer V1, indicating that cortical processing does not strive to separate form and colour information. Oriented cells were five times more frequent than non-oriented cells. Thus, the vast majority of colour-coded cells are orientation tuned. Based on response profiles across a 4 deg square figure, and the relative frequency of oriented and non-oriented cells, we estimate that the cortical colour signal is 5-6 times stronger for the edges than for the surface of the figure. The frequency of oriented colour cells and their ability to code edge polarity indicate that these cells play a major role in the representation of surface colour.

Algorithms↗
PubMed1999

Age-related changes in the associations of social network ties with mortality risk.

Age-related changes in the associations of social network ties with mortality risk were investigated using data from the Terman Life-Cycle Study (L. M. Terman, 1925; L. M. Terman & M. H. Oden, 1947, 1959). Marital status, number of living children, number of living siblings, and number of group memberships in 1940, 1950, 1960, and 1977 were reported across middle adulthood by 697 men and 544 women, with mortality follow-up as of 1991. Initial analyses confirmed previous work indicating that marital history (men only), number of children (both genders), and organizational memberships (both genders) are predictive of mortality risk. Further analyses compared the associations between these social ties and mortality prior to age 70 and at age 70 and older. Results indicated that for men, experiencing marital dissolution and subsequently remarrying is a stronger predictor of mortality risk prior to age 70 (p = .05), whereas for women, number of children (p < .05) is a stronger predictor of mortality risk after age 70. Implications of these age-related changes in social ties and mortality risk are discussed.

Age Factors↗