Rashmi Babbar

Role of cardiovascular reactivity to mental stress in predicting future hypertension

Hypertension (HT) has been known since times immemorial to be one of the major causes of morbidity and mortality. It contributes to atherosclerotic cardiovascular disease, increasing its risk 2–3 times and is also associated with dyslipidemia, insulin resistance, glucose intolerance and obesity 1. The age of onset of hypertension is now earlier than before, making it essential that early detection of people who could be future hypertensives is done. Therefore, cardiovascular reactivity to stress in predicting future hypertension becomes important. In this fast paced age most people are exposed to mental stress which is the most common and prevalent form of stress. Increase in blood pressure (BP) in response to emotional arousal is well known, but support for this hypothesis of reactivity in predicting future hypertension is limited. We are attempting here to put forth a review of the various endeavours done so far to support this hypothesis.

Antihypertensive and Antioxidant Action of Amlodipine and Vitamin C in Patients of Essential Hypertension

The etiology of essential hypertension includes increased oxidative stress. The role of antihypertensive drug amlodipine as an antioxidant and the benefit of addition of vitamin C, an antioxidant to antihypertensive therapy were studied. Forty male patients of essential hypertension were randomly divided into two groups and treated with 5 mg amlodipine. In addition one group also received 1000 mg vitamin C (as two 500 mg tablets) once daily for three months. Although blood pressure decreased in both groups, the systolic blood pressure in patients given vitamin C was less (126.4 ± 7.47) compared to the other group (130.9 ± 7.27). A decrease in malondialdehyde, an increase in erythrocyte sodium-potassium adenosine triphosphatase (Na+ K+ ATPase) and an increase in the superoxide dismutase levels were observed in both groups. The increase in SOD was statistically more in the patients given vitamin C in addition to amlodipine (0.1717 ± 0.0150 compared to 0.152 ± 0.0219 units/100 ml assay). In spite of the known antihypertensive, antioxidant activity, similarity in correcting endothelial dysfunction independently, giving the two drugs together and early introduction of vitamin C perhaps decreases oxidative stress and augments the antioxidant status. This may prevent further vascular damage due to oxidative stress, leading to a better prognosis in essential hypertension patients.

Terminalia arjuna Enhances Baroreflex Sensitivity and Myocardial Function in Isoproterenol-Induced Chronic Heart Failure Rats

Chronic heart failure (CHF) is characterized by left ventricular (LV) dysfunction along with impaired autonomic control functions. Herbal drugs are increasingly being used in the treatment of cardiovascular disorders. The present study was designed to examine the protective effect of Terminalia arjuna (T arjuna) bark extract on LV and baroreflex function in CHF and to elucidate the possible mechanistic clues in its cardioprotective action. The baroreflex was evaluated by measuring the changes in heart rate (HR) with changes in arterial blood pressure induced by bolus injections of phenylephrine (vasoconstrictor) and sodium nitroprusside (vasodilator). T arjuna bark extract and fluvastatin were tested/administered therapeutically and prophylactically in isoproterenol-induced rat model of CHF. Fifteen days after isoproterenol administration, rats exhibited cardiac dysfunction, hypertrophy, and LV remodeling along with reduced baroreflex sensitivity. Prophylactic and therapeutic treatment with T arjuna improved cardiac functions and baroreflex sensitivity. It also attenuated hypertrophy and fibrosis of the LV. Fluvastatin treatment exerted a similar protective effect against myocardial remodeling and heart failure. Further, T arjuna and fluvastatin significantly reduced oxidative stress and inflammatory cytokine level in CHF rats. In conclusion, T arjuna exerts beneficial effect on LV functions, myocardial remodeling, and autonomic control in CHF possibly through maintaining endogenous antioxidant enzyme activities, inhibiting lipid peroxidation and cytokine levels.

Correlation Between Cognitive Functions and Nitric Oxide Levels in Patients with Dementia

Dementia is defined as a clinical syndrome characterized by acquired loss of cognitive and emotional abilities, severe enough to interfere with daily functioning and quality of life. Event related potentials (ERP) are sensitive to task variables that relate to cognitive behavior. They might be altered in patients with disorders of cognition such as dementia. Application of the P300 ERP component to the study of cognitive disorders provides a means of quantifying the level of mental impairment. At high levels, nitric oxide (NO), which is produced by microglia due to induction of nitric oxide synthase (NOS), is neurotoxic and may play a role in neurodegeneration. In our study an attempt has been made to record ERP in patients of mild and moderate dementia and to correlate their findings with nitric oxide levels in CSF and serum. Twenty patients with dementia were selected as cases and 20 subjects as controls, which were further subdivided according to the age groups. Both dementia cases and controls were assessed by minimental state examination (MMSE) and clinical dementia rating scale (CDRS) for evaluating the degree of dementia. It was observed that the MMSE score was reduced in demented cases. P300 latency was significantly delayed in mild and moderate cases of dementia. However, no change was seen in NO levels of cerebrospinal fluid (CSF) and serum in dementia cases and controls. A negative correlation was found between MMSE and P300 latency. Hence we conclude that cognitive impairment in demented patients is reflected in P300 latency but not in NO levels in CSF and serum.

Comparative study of autonomic nervous system activity in malnourished and normal children in India.

Information on the relationship between autonomic functions and malnutrition in children is scant. In the present study, autonomic function tests were conducted in 30 normal subjects and 30 malnourished children aged between 5 and 10 years. The tests performed included tests for parasympathetic functions (resting heart rate, standing-to-lying ratio, lying-to-standing ratio and Valsalva ratio) and tests to assess sympathetic function (hand grip test, galvanic skin resistance). The malnourished children had significantly lower mean weights-for-age (-2.6 Z vs -1.5 Z; p = 0.001), heights-for-age (-2.5 Z vs -1.5 Z; p = 0.001) and weights-for-height (-1.6 Z vs -0.8 Z; p = 0.001). Parasympathetic function tests evaluated were significantly affected in malnourished children. Resting heart rate was significantly higher in the malnourished group (90.6 vs 82.5/min; p = 0.001). The other parasympathetic function tests had significantly lower mean values than in the control group, namely, standing-to-lying ratio (1.25 vs 1.32; p = 0.026), lying-to-standing ratio (1.23 vs 1.29; p = 0.021) and Valsalva ratio (1.26 vs 1.28; p = 0.037). Of the sympathetic function tests conducted, there were no differences between the two groups for hand grip test but galvanic skin resistance was significantly higher in the malnourished subjects (190.1 vs 149.73; p = 0.001). It is concluded that autonomic nervous system function is significantly compromised in malnourished children.

Presbycusis and auditory brainstem responses: a review

Abstract Age-related hearing loss or presbycusis is a complex phenomenon consisting of elevation of hearing levels as well as changes in the auditory processing. It is commonly classified into four categories depending on the cause. Auditory brainstem responses (ABRs) are a type of early evoked potentials recorded within the first 10 ms of stimulation. They represent the synchronized activity of the auditory nerve and the brainstem. Some of the changes that occur in the aging auditory system may significantly influence the interpretation of the ABRs in comparison with the ABRs of the young adults. The waves of ABRs are described in terms of amplitude, latencies and interpeak latency of the different waves. There is a tendency of the amplitude to decrease and the absolute latencies to increase with advancing age but these trends are not always clear due to increase in threshold with advancing age that act a major confounding factor in the interpretation of ABRs.

Migraine: is it related to hormonal disturbances or stress?

Background Common neurological syndrome (migraine without aura) is more common among women than men. Migraine is among the top 20 causes of disability. Menstruation is known to be a powerful trigger for migraine, and so is stress, but the presentation of headache is similar in both. Also, women are more vulnerable to stress as well as migraine, and this makes a complex relationship of menstruation, stress, and migraine. Objective This study was done to understand the association of hormonal fluctuation in menstruation and stress with common migraine. Materials and methods A cross-sectional comparative study was conducted in 40 young adult females, of whom 20 participants were cases of migraine without aura (18–35 years old), and the remaining 20 participants were age-matched controls. The study was done in Maulana Azad Medical College, New Delhi. Study participants were selected on the basis of International Headache Society (ICHD-IIA1.1) (2004) classification. Study participants with neurological disorders, chronic diseases, and disease suggestive of any hormonal disturbances were excluded. Clinically diagnosed migraine cases were asked to maintain a headache diary and to fill in the Depression Anxiety Stress Scales questionnaire. Biochemical assessment of hormonal status for thyroid-stimulating hormone, triiodothyronine, thyroxine, estrogen, follicle-stimulating hormone, luteinizing hormone, and prolactin was also done on the second day of their menstrual cycle. We used the Mann–Whitney U test to compare hormonal levels and the χ2 test to compare anxiety- or depression-related stress among the migraine and nonmigraine groups. Results Significantly higher values of prolactin were observed in cases (mean ± standard deviation, 152.7 mIU/L±30.5) compared to controls (76.1 mIU/L±8.7), with a P-value <0.001. There was no statistically significant difference observed in levels of thyroid-stimulating hormone (P=0.081), estrogen (P=0.086), luteinizing hormone (P=0.091), or follicle-stimulating hormone (P=0.478). Also, anxiety with stress or depression with stress was significantly higher among the migraine group than the controls (P=0.002). Odds of any stress in migraine were higher in the migraine group than in the nonmigraine group (odds ratio 12, 95% confidence interval 2.7–53.33). Conclusion Migraine, particularly without aura, in women is mainly associated with stress-related anxiety or depression, and are more susceptible to stress in the premenstrual period.

Auditory Brainstem Responses & Nerve Conduction Velocity in Essential Hypertension

Auditory Brainstem Responses (ABRs) is an electrophysiologic technique that represents the synchronized ac- tivity of the brainstem and the auditory nerve. Nerve conduction velocity (NCV) is part of electrodiagnostic procedures that help in evaluating the type and degree of abnormalities of the peripheral nerves. The aim of our study was to assess whether central or peripheral nerves are involved in hypertensive patients. 20 patients of primary hypertension were se- lected between the ages of 40-60 years of either sex along with 20 age- and sex-matched normotensives. ABRs along with NCV, both sensory and motor components of the median nerve were performed using standard techniques. Auditory threshold increased significantly in the hypertensive group compared with controls (p < 0.05). There was a significant pro- longation of absolute peak latencies of waves I, II and V and interpeak latency III-V. However, no significant difference was observed in the NCV between the hypertensives and controls. We conclude that there was a significant correlation of rise in systolic and diastolic blood pressure with absolute peak latencies of ABRs in hypertensive patients. However, no significant difference in nerve conduction velocity was seen.

Effect of pulse pressure on cognitive function

The current guidelines for the management of hypertension rest almost completely on the measurement of systolic and diastolic blood pressures, two specific inflection points of the blood pressure (BP) wave, which are usually considered in isolation [1,2]. However, BP propagates through the arterial tree as a repetitive continuous wave and is more accurately described as consisting of a pulsatile component (pulse pressure) and a steady component (mean pressure) [3]. Pulse pressure is the difference between systolic and diastolic BP and depends on ventricular ejection, arterial stiffness and the timing of wave reflections.