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Biomedical subjects

C Ramesh

Publications and source records attributed to C Ramesh.

36 records · Page 2Linked to original sources
PubMed1994

Lactate sensitivity and cardiac cholinergic function in panic disorder.

Using spectral analysis of the continuous time series signal before and during lactate and placebo infusions, the authors studied heart rate variability in six patients with panic disorder and nine normal comparison subjects. The decrease in high-frequency (0.20-0.50 Hz) power and the increase in sympathovagal ratios (mid-frequency [0.07-0.15 Hz] to high-frequency powers) after the administration of intravenous sodium lactate were significantly greater in the patients than in the normal subjects after correction of the values for the amount of lactate infused. This result suggests an exaggerated cardiac vagal withdrawal in patients with panic disorder during lactate infusions.

Adult↗
PubMed1993

Decreased heart rate variability in panic disorder patients: a study of power-spectral analysis of heart rate.

We have previously found decreased standard deviations and mean consecutive differences of R-R intervals in panic disorder patients in standing posture, compared with control subjects. In the present study, we used spectral analysis of heart rate variability to examine autonomic function in 21 panic disorder patients and 21 normal control subjects. Patients had a significantly lower standard deviation of heart rate in supine as well as standing postures. Absolute low frequency power (0.01-0.05 Hz) was also significantly lower in panic disorder patients in standing postures. Upon standing, the panic disorder patients had significantly higher relative mid-frequency power (0.07-0.15 Hz). During a standing deep-breathing condition at six breaths per minute, the patients had a significantly decreased absolute and relative mid-frequency (0.07-0.15 Hz) power compared with control subjects. These findings suggest a decrease in cholinergic and a relative increase in adrenergic responsiveness in panic disorder patients compared with control subjects.

Adrenergic Fibers↗
PubMed1993

Sexual dysfunction during antidepressant treatment.

BACKGROUND: The reported incidence of sexual dysfunction associated with antidepressant medication varies from 1.9% to 92%. The majority of studies reporting incidences were not systematically conducted. METHOD: We interviewed 60 patients (22 men and 38 women, with anxiety and mood disorders) who were being treated with various antidepressants. We used a questionnaire focused on sexual side effects and other side effects. RESULTS: The incidence of sexual dysfunction during antidepressant use in our study is 43.3%. The sexual dysfunction was not limited to any particular diagnostic group nor to any particular antidepressant. There was no significant correlation between sexual dysfunction and anticholinergic side effects. The incidence of painful orgasm with antidepressants was 18% among males in our study. CONCLUSION: The relatively high incidence of sexual dysfunction associated with antidepressant treatment in this systematic study emphasizes the importance of a detailed inquiry about sexual side effects as this interferes with treatment compliance.

Adult↗
PubMed1992

Effects of yohimbine on heart rate variability in panic disorder patients and normal controls: a study of power spectral analysis of heart rate.

We studied the effects of yohimbine on heart rate (HR) variability in 13 normal controls and 13 patients with panic disorder. Yohimbine produced a significant increase in SD of HR in standing posture in both patients (p = 0.01) and normal controls (p = 0.025). Panic disorder patients had a significant increase in standing absolute midfrequency (MF) power (0.07-0.15 Hz) after administration of yohimbine (p = 0.002). The ratio of post- to preyohimbine standing MF power (0.07-0.15 Hz) during standing was significantly higher in patients as compared with controls (2.3 +/- 1.08 vs. 1.33 +/- 0.38; p = 0.01), which suggests an increased responsivity of panic disorder patients to the adrenergic effects of yohimbine.

Adult↗
PubMed1992

Effect of imipramine treatment on heart rate variability measures.

Recently, heart rate (HR) variability has received considerable attention, and a decreased HR variability has been linked to a significant risk of cardiovascular illness. We have previously reported such a decreased variability in panic disorder patients. In this study, we report on HR variability in 12 depressed and 6 panic disorder patients at baseline and 1 and 3 weeks of treatment with imipramine as measured by the standard deviation, mean consecutive difference and the standard deviation of the mean consecutive difference of the R-R intervals in supine, supine deep breathing and standing postures. In all subjects, imipramine (mean dose: 70 mg/day) produced a significant decrease in heart rate variability at week 3 as measured by the above variables. This decrease in HR variability during imipramine treatment is probably due to its anticholinergic effects.

Adult↗
PubMed1991

Heart rate variability in patients with major depression.

We have previously reported decreased heart rate variability upon standing in panic disorder patients compared with controls. In this study, we extend our report to include patients with major depression (n = 19). Compared to normal controls (n = 20) and panic disorder patients (n = 30), there was no significant difference in the immediate changes in heart rate upon standing in the depressed group. The standing heart rate variability (R-R variability) was significantly lower in panic disorder patients compared to both normal controls and depressed patients as indicated by the corrected standard deviations, the corrected mean consecutive difference, the corrected standard deviation of the mean consecutive difference of the R-R intervals, and the high frequency variability in successive R-R intervals, suggesting an increased vagal withdrawal in panic disorder patients, especially upon standing. There was no significant difference in any of the heart rate variability measures between depressed patients and normal controls.

Adult↗
PubMed1991

The changes of thyroid hormone during pharmacological treatment of panic disorder patients.

1. Because imipramine has lowered T4 in uncontrolled studies we examined the effect of imipramine on serum thyroid levels in panic disorder patients in a double-blind placebo and diazepam treatment controlled study. 2. Treatment with imipramine (10 subjects) was associated with a significant decrease of T4 and FTI and treatment with diazepam (8 subject) was associated with a significant decrease of T4. However, there was no significant difference across treatment groups. 3. This finding suggests that previously reported decreases in thyroid hormones during antidepressant therapy may be due to nonspecific effects of treatment rather than to the drug itself.

Adult↗
PubMed1991

A comparative study of immune status in panic disorder patients and controls.

Alterations of immunocompetence in various mental disorders have been reported. We studied white blood cell counts and immunoglobulin levels in 59 panic disorder patients and 30 controls. The significantly increased IgA levels and tendency toward increase in other immunoglobulins in panic disorder patients suggest an immune dysfunction.

Adult↗
PubMed1990

Decreased R-R variance in panic disorder patients.

To investigate autonomic function in panic disorder patients (n = 30), we compared postural changes in heart rate and the R-R interval variance in patients and normal controls (n = 20). There was no significant difference in the immediate changes in heart rate upon standing between the groups. R-R variance was significantly decreased during resting supine condition in patients as indicated by the corrected standard deviation of the R-R intervals. The standing R-R variance was significantly lower than that of normal controls as indicated by the corrected standard deviations, the corrected mean consecutive difference and the corrected standard deviation of the mean consecutive difference of the R-R intervals, suggesting an increase in vagal withdrawal in patients, especially upon standing. If this finding is specific to panic disorder patients, it may be a useful peripheral marker for this condition.

Adult↗
PubMedDate not supplied

Effect of age on QT variability.

Heart rate variability is influenced significantly by age. Recent studies have shown the utility of QT variability to study temporal repolarization lability, and increased QT variability is reportedly associated with sudden death. Because beat-to-beat QT interval variability appears to closely follow heart rate variability, this study investigated the relationship between age and QT variability. We obtained QT variability measures in 34 adults (22-55 years of age) and 15 children (6-14 years of age) using a novel algorithm to compute beat-to-beat QT intervals. QT variability corrected for mean QT interval was significantly inversely correlated with age. Coherence in the band of 0 to 0.5 Hz and high-frequency coherence (0.15-0.5 Hz) were also significantly inversely correlated with age. QTvi (QT variability corrected for mean QT interval over heart rate variability corrected for mean heart rate) was not significantly related to age in supine posture during spontaneous or controlled breathing, whereas there was a modest negative relationship in standing posture. These findings suggest that coherence between QT and heart rate time series appears to be modulated by cardiac vagal activity.

Adolescent↗
PubMedDate not supplied

Risk factors for cardiovascular illness in panic disorder patients.

Supine and standing heart rate (HR) and blood pressure measures were compared among 19 nonsmoking normal controls, 29 smoking patients and 36 nonsmoking patients with panic disorder. The smoking patients had a significantly higher supine HR, standing diastolic blood pressure, standing mean blood pressure and supine and standing cardiac load measures compared to both patient nonsmokers and controls. There was no significant difference between controls and nonsmoking patients for any of the above measures except for the higher standing HR and the delta increase in HR upon standing in female panic disorder patients which suggests increased adrenergic activity. When lipid values of panic disorder patients (n = 92) were compared to National Reference Values for their sex and age for an increased risk of cardiovascular illness, there was no significant risk with regard to plasma levels of total cholesterol, high-density lipoprotein cholesterol or low-density lipoprotein cholesterol.

Adult↗
PubMedDate not supplied

Factors influencing the evaluation of an article in cancer literature.

Casual Interpretation of results in a given article has several pitfalls. In order to assess the strengths and limitations of a given article several factors need to be considered. This review article is intended to list, classify and describe briefly the factors that should be considered in the evaluation of an article. The three primary criteria which help in proper assessment of an article are (1) Accurate and adequate description of material and methods; (2) Data on the total sample size and elimination criteria; (3) Statistical methodology employed.

Bias↗