Electrical stimulation of the cochlear nerve in rats: analysis of c-Fos expression in auditory brainstem nuclei.

We investigated functional activation of central auditory brainstem nuclei in response to direct electrical stimulation of the cochlear nerve using c-Fos immunoreactivity as a marker for functional mapping. The cochlear nerve was stimulated in the cerebellopontine angle of Lewis rats applying biphasic electrical pulses (120-250 muA, 5 Hz) for 30 min. In a control group, bilateral cochlectomy was performed in order to assess the basal expression of c-Fos in the auditory brainstem nuclei. The completeness of cochlear ablations and the response of auditory brainstem nuclei to electrical stimulation were electrophysiologically verified. C-Fos immunohistochemistry was performed using the free floating method. In anaesthetized animals with unilateral electrical stimulation of the cochlear nerve, increased expression of c-Fos was detected in the ipsilateral ventral cochlear nucleus (VCN), in the dorsal cochlear nucleus bilaterally (DCN), in the ipsilateral lateral superior olive (LSO) and in the contralateral inferior colliculus (IC). A bilateral slight increase of c-Fos expression in all subdivisions of the lateral lemniscus (LL) did not reach statistical significance. Contralateral inhibition of the nuclei of the trapezoid body (TB) was observed. Our data show that unilateral electrical stimulation of the cochlear nerve leads to increased expression of c-Fos in most auditory brainstem nuclei, similar to monaural auditory stimulation. They also confirm previous studies suggesting inhibitory connections between the cochlear nuclei. C-Fos immunoreactivity mapping is an efficient tool to detect functional changes following direct electrical stimulation of the cochlear nerve on the cellular level. This could be particularly helpful in studies of differential activation of the central auditory system by experimental cochlear and brainstem implants.

Is systolic blood pressure sufficient for classification of blood pressure and determination of hypertension based on JNC-VI in an Iranian adult population? Tehran lipid and glucose study (TLGS).

The purpose of this study was to determine if systolic blood pressure (SBP) by itself is sufficient for the JNC-VI (Sixth Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure)-based classification of blood pressure of Tehranian adult population. Clinically, SBP and diastolic blood pressure (DBP) are sometimes at different stages in the same individual and the higher stage is considered to classify blood pressure level. The prevalence of disparate levels of SBP and DBP has only recently been noticed. Some researches have reported the importance of SBP level, and not DBP, in determining the appropriate classification of hypertension even in those undergoing treatment. Data were collected for 3823 men and 5159 women aged 20-69 years who were not using antihypertensive medication, in the Tehran Lipid and Glucose Study (TLGS), a cross-sectional phase of a large epidemiological study first established in 1999. The study used the mean of two separate blood pressure measurements in each individual. High blood pressure is defined according to the highest level of SBP or DBP. In 86.3% of the subjects, blood pressure stage was determined according to SBP and in 90.0% of them according to DBP. In 77.4% of the subjects (75.7% of men and 78.7% of women), SBP determined blood pressure in the same stage as DBP did. The role of SBP was the most prominent in age groups 20-29 and 60-69 years (91.4 and 90.8%, respectively) and the least in age group 40-49 years (80.4% of the subjects). DBP had a more prominent role in younger ages and the least significance in older ages. In conclusion, SBP has a more prominent role than DBP in determining blood pressure stage according to JNC-VI only in the 60-69-year-old group. The role of DBP is more prominent in other age groups.

Distribution of blood pressure and prevalence of hypertension in Tehran adult population: Tehran Lipid and Glucose Study (TLGS), 1999-2000.

The purpose of this study was to estimate the current prevalence and distribution of hypertension in an adult Tehranian population. Data were collected for 3343 men and 5148 women aged 20-69 years in the Tehran Lipid and Glucose Study (TLGS), which is a cross-sectional phase of a large epidemiologic study, first established in 1999. The study used the mean of two separate blood pressure (BP) measurements in each individual. Twenty-two percent (23% of women vs 20% of men, P = 0.01) had hypertension according to 'JNC-VI' and 'WHO-ISH' criteria. The average systolic BP (SBP), diastolic BP (DBP) and pulse pressure of hypertensive participants were 31, 16, and 15 mm Hg higher than the corresponding value for normotensives, respectively. Thirty-six percent of participants with JNCVI-based hypertension were using antihypertensive medication (23% of men and 43% of women). Of these, 40% (45% of men and 39% of women) had normal BP. Hypertension awareness was 50% in these participants (57% in men vs 37% in women, P < 0.001). Data for 3179 men and 4646 women aged 20-69 years with no antihypertensive treatment were used for analysis of BP measures. Of these, 15% (16% of men and 14% of women, P = 0.006) had high and 85% (84% of men and 86% of women) normal or high-normal BP levels according to JNC-VI. Prevalence of optimal BP was 49% (47% of men and 51% of women). Mean SBP was 117.8 +/- 16.6 and 116.4 +/- 16.4 mm Hg in men and women, respectively (P < 0.001). The equivalent values were 77.4 +/- 10.7 and 77.3 +/- 9.9 mm Hg for DBP (P = 0.5) and 40.4 +/- 12 and 39.1 +/- 11.7 mm Hg for pulse pressure (P < 0.001). A relatively high prevalence of JNC-VI/WHO-ISH defined hypertension was found in the TLGS adult population with 50% undiagnosed and 60% uncontrolled hypertension. These findings emphasise further considerations for detection and better management of hypertension in the urban population of Tehran.

Cardiovascular risk factors in an Iranian urban population: Tehran lipid and glucose study (phase 1).

OBJECTIVES: Coronary artery disease is becoming more prevalent in developing countries, particularly in urban areas. This study was conducted to determine the prevalence of cardiovascular risk factors among Tehran urban population. METHODS: The prevalence and distribution of high blood pressure, cigarette smoking, dyslipoproteinemia, diabetes mellitus, and obesity was determined in 15,005 subjects, aged three years and over, selected by cluster random sampling in Tehran urban district-13 between February 1999 to August 2001. Total energy intake, percent of energy derived from protein, carbohydrate, and fat were assessed in a subsidiary of 1,474 persons by means of two 24-hour dietary recalls. RESULTS: In adults, 78% of men and 80% of women presented at least one CVD risk factor. The percentage of adult women with two or more risk factors was significantly greater than the one for men. Prevalence of DM, hypertension, obesity, high TC, low HDL, high TGs, and smoking was 9.8, 20.4, 14.4, 19.3, 32, 5.3, and 22.3%, respectively. In children and adolescents, two or more CVD risk factors were found in 9% of boys and 7% of girls. Prevalence of hypertension, obesity, high TC, low HDL, and high TGs, was 12.7, 5.2, 5.1, 10.2, and 5%, respectively. The mean percentage values of energy intake derived from carbohydrate, protein, and fat were 57.8 +/- 6.9, 11.1 +/- 1.8, and 30.9 +/- 7.2, respectively. CONCLUSION: The prevalence of cardiovascular risk factors among Tehran urban population is high; particularly of high total cholesterol, low HDL cholesterol levels, and high waist to hip ratio. An effective strategy for life style modification is a cornerstone of a population approach to the cardiovascular risk factors. Moreover, these results will serve as a baseline for assessment of future trends in the risk factors studied.

Serum lipid levels in an Iranian population of children and adolescents: Tehran lipid and glucose study.

Data from 3148 participants aged 3-19 years (1447 males and 1701 females) in the cross-sectional phase of Tehran lipid and glucose study (February 1999-May 2000) were used to determine serum lipid levels [total cholesterol (TC), triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)] after 12-14 hours overnight fast. The values were analyzed by sex and age. Mean serum TC concentration was 170 mg/dl. TC was significantly greater in females than males (173 vs. 167 mg/dl, p < 0.05). The 90th and 95th percentiles for serum TC were 211 and 227 mg/dl, respectively. There was a significant decrease in mean TC in males during puberty. Thirty-one percent of population had TC values between 170 and 199 mg/dl and 16% had values of 200 mg/dl or greater. The mean TGs values were 103 for males and 108 mg/dl for females [non-significant (NS)]. The prevalence of high-risk values of TGs increased with age in males, reaching a peak at 17-19 years. The mean HDL-C level was 45 mg/dl. Mean HDL-C was highest at 7-10 years of age and decreased thereafter. The mean LDL-C was 102 in males and 107 mg/dl in females (NS). Twenty-two percent had LDL-C values between 110 and 129 mg/dl and 17% had values 130 mg/dl or greater. The results showed higher levels of TC, LDL-C and TGs and lower HDL-C in Tehranian children and adolescents than other studies. To design comprehensive public health programs to reduce serum lipid levels among Iranian children and adolescents, underlying factors for the high prevalence of dyslipoproteinemia should be sought.

New developments in the detection of vulnerable plaque.

Failure of coronary angiography (luminography) in prediction of future acute coronary syndromes has cast a shadow of doubt over the value of this old gold-standard technique. The fact that angiographically invisible or nonsignificant lesions cause the majority of acute coronary syndromes has driven scientists to develop new diagnostic methods. In this article, we review the ongoing worldwide research on both invasive techniques (such as intravascular angioscopy and colorimetry, ultrasound, thermography, optical coherence tomography, near infrared spectroscopy, Raman spectroscopy, fluorescence emission spectroscopy, elastography, magnetic resonance imaging and spectroscopy, nuclear immunoscintigraphy, electrical impedance imaging, vascular tissue doppler, and shear stress imaging) and noninvasive techniques (such as MRI, contrast-enhanced MRI with and without immunolabeled agents, electron beam computed tomography, multi-slice spiral / helical computed tomography, and nuclear imaging, including positron emission tomography). Each of these techniques and their potential combination holds promise for characterization of plaques responsible for acute coronary syndromes, namely vulnerable plaque.

Association of influenza vaccination and reduced risk of recurrent myocardial infarction.

BACKGROUND: Numerous studies have suggested that microbial agents may promote atherosclerosis. A smaller body of research has suggested that acute respiratory infection may be a risk factor for myocardial infarction (MI). We hypothesized that influenza vaccine might reduce the risk of recurrent MI in patients with documented coronary heart disease (CHD). METHODS AND RESULTS: A case-control study was performed on 218 CHD patients seen at Memorial Hermann Hospital during the influenza season of October 1997 through March 1998. Patients who experienced new MI were included in the case group, and those who did not experience new MI or unstable angina were assigned to the control group. Data were collected by structured review of patients' charts and through a subsequent telephone survey. Adjusted for history of influenza vaccination in previous years, multivariate logistic regression revealed risk of MI to be associated with current hypertension (OR 4.96, 95% CI 2.06 to 11.96, P<0.0001), hypercholesterolemia (OR 4.08, 95% CI 1.67 to 9.99, P=0.002), smoking (OR 3.75, 95% CI 1.76 to 7.98, P=0.001), and influenza vaccination (OR 0.33, 95% CI 0.13 to 0.82, P=0.017). Despite significant association in univariate analysis, multivitamin therapy and physical exercise were not associated with risk of reinfarction in multivariate analysis. CONCLUSIONS: In this study in patients with chronic CHD, vaccination against influenza was negatively associated with the development of new MI during the same influenza season. However, to address causal inference, examination of prospective data sets will be needed.