Comparative evaluation of shear bond strength and penetration of self-etch sealant with and without enamel deproteinization: an in vitro study

AIM

To compare the shear bond strength and penetration ability of self-etch sealant with and without enamel deproteinization.

MATERIALS AND METHODS

A total of 37 sound extracted teeth were selected and 31 teeth were used for testing shear bond strength of self-etch sealant. For this, crowns portions of selected teeth were cut longitudinally with a diamond disc into a mesial and distal half, thereby yielding 62 samples. They were further divided into two groups; in Group 1, samples were deproteinised with 5.25% sodium hypochlorite and a sealant cylinder was built on the proximal surface. In Group 2, sealant cylinders were built without deproteinising the surface. Shear bond strength was tested using Universal Testing Machine. The remaining six teeth were used for penetration evaluation of self-etch sealant. In Group 1, the occlusal surface was deproteinised with 5.25% sodium hypochlorite and self-etch sealant was directly applied. In Group 2, sealant was applied without deproteinisation. The samples obtained after sectioning were observed under scanning electron microscope for sealant penetration. Mann-Whitney test and Chi-square analysis were utilised for statistical analysis.

RESULTS

The results showed that the shear bond strength of the two groups was statistically not significant (p = 0.23). However, the comparison of % penetration revealed a statistically significant difference between the groups (p = 0.016).

CONCLUSION

Deproteinising the enamel surface prior to application of self-etch sealant enhanced the penetration ability of the sealant but did not show any effect on shear bond strength.

CFTR is required for zinc-mediated antibacterial defense in human macrophages

Cystic fibrosis transmembrane conductance regulator (CFTR) is an anion transporter required for epithelial homeostasis in the lung and other organs, with CFTR mutations leading to the autosomal recessive genetic disease CF. Apart from excessive mucus accumulation and dysregulated inflammation in the airways, people with CF (pwCF) exhibit defective innate immune responses and are susceptible to bacterial respiratory pathogens such as Pseudomonas aeruginosa. Here, we investigated the role of CFTR in macrophage antimicrobial responses, including the zinc toxicity response that is used by these innate immune cells against intracellular bacteria. Using both pharmacological approaches, as well as cells derived from pwCF, we show that CFTR is required for uptake and clearance of pathogenic Escherichia coli by CSF-1-derived primary human macrophages. CFTR was also required for E. coli-induced zinc accumulation and zinc vesicle formation in these cells, and E. coli residing in macrophages exhibited reduced zinc stress in the absence of CFTR function. Accordingly, CFTR was essential for reducing the intramacrophage survival of a zinc-sensitive E. coli mutant compared to wild-type E. coli. Ectopic expression of the zinc transporter SLC30A1 or treatment with exogenous zinc was sufficient to restore antimicrobial responses against E. coli in human macrophages. Zinc supplementation also restored bacterial killing in GM-CSF-derived primary human macrophages responding to P. aeruginosa, used as an in vitro macrophage model relevant to CF. Thus, restoration of the zinc toxicity response could be pursued as a therapeutic strategy to restore innate immune function and effective host defense in pwCF.

Histone deacetylase 7: a signalling hub controlling development, inflammation, metabolism and disease

Histone deacetylases (HDACs) catalyse removal of acetyl groups from lysine residues on both histone and non-histone proteins to control numerous cellular processes. Of the 11 zinc-dependent classical HDACs, HDAC4, 5, 7 and 9 are class IIa HDAC enzymes that regulate cellular and developmental processes through both enzymatic and non-enzymatic mechanisms. Over the last two decades, HDAC7 has been associated with key roles in numerous physiological and pathological processes. Molecular, cellular, in vivo and disease association studies have revealed that HDAC7 acts through multiple mechanisms to control biological processes in immune cells, osteoclasts, muscle, the endothelium and epithelium. This HDAC protein regulates gene expression, cell proliferation, cell differentiation and cell survival and consequently controls development, angiogenesis, immune functions, inflammation and metabolism. This review focuses on the cell biology of HDAC7, including the regulation of its cellular localisation and molecular mechanisms of action, as well as its associative and causal links with cancer and inflammatory, metabolic and fibrotic diseases. We also review the development status of small molecule inhibitors targeting HDAC7 and their potential for intervention in different disease contexts.

HDAC7 is an immunometabolic switch triaging danger signals for engagement of antimicrobial versus inflammatory responses in macrophages

The immune system must be able to respond to a myriad of different threats, each requiring a distinct type of response. Here, we demonstrate that the cytoplasmic lysine deacetylase HDAC7 in macrophages is a metabolic switch that triages danger signals to enable the most appropriate immune response. Lipopolysaccharide (LPS) and soluble signals indicating distal or far-away danger trigger HDAC7-dependent glycolysis and proinflammatory IL-1β production. In contrast, HDAC7 initiates the pentose phosphate pathway (PPP) for NADPH and reactive oxygen species (ROS) production in response to the more proximal threat of nearby bacteria, as exemplified by studies on uropathogenic Escherichia coli (UPEC). HDAC7-mediated PPP engagement via 6-phosphogluconate dehydrogenase (6PGD) generates NADPH for antimicrobial ROS production, as well as D-ribulose-5-phosphate (RL5P) that both synergizes with ROS for UPEC killing and suppresses selective inflammatory responses. This dual functionality of the HDAC7-6PGD-RL5P axis prioritizes responses to proximal threats. Our findings thus reveal that the PPP metabolite RL5P has both antimicrobial and immunomodulatory activities and that engagement of enzymes in catabolic versus anabolic metabolic pathways triages responses to different types of danger for generation of inflammatory versus antimicrobial responses, respectively.

The histone deacetylase Hdac7 supports LPS-inducible glycolysis and Il-1β production in murine macrophages via distinct mechanisms

TLRs reprogram macrophage metabolism, enhancing glycolysis and promoting flux through the tricarboxylic acid cycle to enable histone acetylation and inflammatory gene expression. The histone deacetylase (HDAC) family of lysine deacetylases regulates both TLR-inducible glycolysis and inflammatory responses. Here, we show that the TLR4 agonist LPS, as well as agonists of other TLRs, rapidly increase enzymatic activity of the class IIa HDAC family (HDAC4, 5, 7, 9) in both primary human and murine macrophages. This response was abrogated in murine macrophages deficient in histone deacetylase 7 (Hdac7), highlighting a selective role for this specific lysine deacetylase during immediate macrophage activation. With the exception of the TLR3 agonist polyI:C, TLR-inducible activation of Hdac7 enzymatic activity required the MyD88 adaptor protein. The rapid glycolysis response, as assessed by extracellular acidification rate, was attenuated in Hdac7-deficient mouse macrophages responding to submaximal LPS concentrations. Surprisingly however, reconstitution of these cells with either wild-type or an enzyme-dead mutant of Hdac7 enhanced LPS-inducible glycolysis, whereas only the former promoted production of the inflammatory mediators Il-1β and Ccl2. Thus, Hdac7 enzymatic activity is required for TLR-inducible production of specific inflammatory mediators, whereas it acts in an enzyme-independent fashion to reprogram metabolism in macrophages responding to submaximal LPS concentrations. Hdac7 is thus a bifurcation point for regulated metabolism and inflammatory responses in macrophages. Taken together with existing literature, our findings support a model in which submaximal and maximal activation of macrophages via TLR4 instruct glycolysis through distinct mechanisms, leading to divergent biological responses.

SCIMP is a spatiotemporal transmembrane scaffold for Erk1/2 to direct pro-inflammatory signaling in TLR-activated macrophages

Immune cells are armed with Toll-like receptors (TLRs) for sensing and responding to pathogens and other danger cues. The role of extracellular-signal-regulated kinases 1/2 (Erk1/2) in TLR signaling remains enigmatic, with both pro- and anti-inflammatory functions described. We reveal here that the immune-specific transmembrane adaptor SCIMP is a direct scaffold for Erk1/2 in TLR pathways, with high-resolution, live-cell imaging revealing that SCIMP guides the spatial and temporal recruitment of Erk2 to membrane ruffles and macropinosomes for pro-inflammatory TLR4 signaling. SCIMP-deficient mice display defects in Erk1/2 recruitment to TLR4, c-Fos activation, and pro-inflammatory cytokine production, with these effects being phenocopied by Erk1/2 signaling inhibition. Our findings thus delineate a selective role for SCIMP as a key scaffold for the membrane recruitment of Erk1/2 kinase to initiate TLR-mediated pro-inflammatory responses in macrophages.

Nicotinamide riboside attenuates age-associated metabolic and functional changes in hematopoietic stem cells

With age, hematopoietic stem cells (HSC) undergo changes in function, including reduced regenerative potential and loss of quiescence, which is accompanied by a significant expansion of the stem cell pool that can lead to haematological disorders. Elevated metabolic activity has been implicated in driving the HSC ageing phenotype. Here we show that nicotinamide riboside (NR), a form of vitamin B3, restores youthful metabolic capacity by modifying mitochondrial function in multiple ways including reduced expression of nuclear encoded metabolic pathway genes, damping of mitochondrial stress and a decrease in mitochondrial mass and network-size. Metabolic restoration is dependent on continuous NR supplementation and accompanied by a shift of the aged transcriptome towards the young HSC state, more youthful bone marrow cellular composition and an improved regenerative capacity in a transplant setting. Consequently, NR administration could support healthy ageing by re-establishing a more youthful hematopoietic system.

Class IIa Histone Deacetylases Drive Toll-like Receptor-Inducible Glycolysis and Macrophage Inflammatory Responses via Pyruvate Kinase M2

Histone deacetylases (HDACs) drive innate immune cell-mediated inflammation. Here we identify class IIa HDACs as key molecular links between Toll-like receptor (TLR)-inducible aerobic glycolysis and macrophage inflammatory responses. A proteomic screen identified the glycolytic enzyme pyruvate kinase M isoform 2 (Pkm2) as a partner of proinflammatory Hdac7 in murine macrophages. Myeloid-specific Hdac7 overexpression in transgenic mice amplifies lipopolysaccharide (LPS)-inducible lactate and promotes a glycolysis-associated inflammatory signature. Conversely, pharmacological or genetic targeting of Hdac7 and other class IIa HDACs attenuates LPS-inducible glycolysis and accompanying inflammatory responses in macrophages. We show that an Hdac7-Pkm2 complex acts as an immunometabolism signaling hub, whereby Pkm2 deacetylation at lysine 433 licenses its proinflammatory functions. Disrupting this complex suppresses inflammatory responses in vitro and in vivo. Class IIa HDACs are thus pivotal intermediates connecting TLR-inducible glycolysis to inflammation via Pkm2.

Lysine Deacetylases and Regulated Glycolysis in Macrophages

Regulated cellular metabolism has emerged as a fundamental process controlling macrophage functions, but there is still much to uncover about the precise signaling mechanisms involved. Lysine acetylation regulates the activity, stability, and/or localization of metabolic enzymes, as well as inflammatory responses, in macrophages. Two protein families, the classical zinc-dependent histone deacetylases (HDACs) and the NAD-dependent HDACs (sirtuins, SIRTs), mediate lysine deacetylation. We describe here mechanisms by which classical HDACs and SIRTs directly regulate specific glycolytic enzymes, as well as evidence that links these protein deacetylases to the regulation of glycolysis-related genes. In these contexts, we discuss HDACs and SIRTs as key control points for regulating immunometabolism and inflammatory outputs from macrophages.

Impact of a modified carbonated beverage on human dental plaque and salivary pH: an in vivo study

BACKGROUND

To assess the plaque and salivary pH changes at different time intervals in vivo after consumption of a carbonated beverage modified with sodium fluoride and calcium phosphate.

MATERIALS AND METHODS

Twenty-four subjects aged 18-25 years were recruited and randomly assigned to three groups (group A, original drink Sprite; group B, Sprite with sodium fluoride; group C, Sprite with calcium phosphate). Collection of pooled plaque and unstimulated saliva was done before and after the drinks were consumed by the subjects at 5-, 10-, 20- and 30-minute intervals.

RESULTS

The pH rise was higher with group C for plaque and group B for saliva.

CONCLUSIONS

Modification of the test carbonated beverage with calcium phosphate and fluoride may exert some protective potential, especially in high caries risk candidates.

Coronary heart disease in low socioeconomic status subjects in India: "an evolving epidemic"

In developing countries such as India, the focus for long has been on the control of acute and chronic infections and communicable diseases. Mortality data from Global Burden of Diseases Studies has revealed that cardiovascular diseases, especially coronary heart disease are important causes of death. Worldwide, of the 17.5 million deaths from cardiovascular diseases, 20% deaths ocurred in high income countries, 8% in upper-middle income countries, 37% in lower-middle income countries and 35% in low income countries including India. There is epidemiological evidence that health transition is occurring rapidly in low and middle income countries. In many regions of these countries cardiovascular diseases, especially coronary heart disease, are more prevalent among the illiterate and low socioeconomic subjects. Recent case-control studies in India have reported that being illiterate or poor is an independent risk factor for acute myocardial infarction. Many of the standard coronary risk factors such as smoking and tobacco use, low physical activity, high dietary fat intake, uncontrolled hypertension, uncontrolled hypercholesterolemia and diabetes are also more common among the low socioeconomic individuals. Data shows that access and affordability for acute care managements and long term secondary prevention practices and compliance are lacking in these subjects. These attributes forecast a grim scenario for the evolving epidemic of coronary heart disease in India.

Do healthy potential kidney donors in india have an average glomerular filtration rate of 81.4 ml/min?

BACKGROUND

Until now, a normal reference range for glomerular filtration rate (GFR) in adult Indian potential kidney donors has not been determined and values from a western population are being used as reference.

AIM

To determine the reference range of GFR in healthy adult Indian potential kidney donors.

BASIC PROCEDURES

GFR was measured in 610 (250 male, 360 female, average age 35.16 years) healthy potential kidney donors using the 99mTc-DTPA (diethylenetriamine pentaacetic acid) two-plasma sample method of Russell.

RESULTS

The mean body surface area (BSA)-normalized GFR value of a young healthy Indian adult potential kidney donor was calculated as 81.4 +/- 19.4 ml/min/1.73 m2 BSA--for males it was 82.3 +/- 21.3 ml/min/1.73 m2 BSA and for females 80.8 +/- 18.1 ml/min/1.73 m2 BSA. There was no significant difference between derived mean GFR values in males and females with a p value of 0.37.

CONCLUSIONS

The normal GFR value for the healthy Indian adult potential kidney donor appears to be much lower than the accepted value for a western population. The mean GFR value of a young healthy Indian adult potential kidney donor is 81.4 +/- 19.4 ml/min/1.73 m2 BSA, which is significantly different from the normal value of 109-125 ml/min derived from a western population. These findings might be useful in deciding on a suitable kidney donor in an Indian context.

Serial epidemiological surveys in an urban Indian population demonstrate increasing coronary risk factors among the lower socioeconomic strata

OBJECTIVE

To determine trends of coronary risk factors in an Indian urban population and their association with educational level as marker of socioeconomic status.

METHODS

Two successive coronary risk factor surveys were performed in randomly selected individuals. In the first study (in 1995) 2212 subjects (1415 men, 797 women) and in the second (in 2002) 1123 subjects (550 men, 573 women) were studied. Details of smoking, physical activity, hypertension, diabetes, coronary heart disease, body-mass index, waist-hip ratio, blood pressure and electrocardiography were evaluated. Fasting blood was examined for lipid levels in 297 (199 men, 98 women) in the first and in 1082 (532 men, 550 women) in the second study. Educational status was classified into Group 0: no formal education, Group I: 1-10 years, Group II: 11-15 years, and Group III: > 16 years. Current definitions were used for risk factors in both the studies.

RESULTS

Prevalence of coronary risk factors, adjusted for age and educational status, in the first and second study in men was smoking/tobacco in 38.7 vs. 40.5%, leisure time physical inactivity in 70.8 vs. 66.1%, hypertension (> or = 140 and/or 90 mm Hg) in 29.5 vs. 33.7%, diabetes history in 1.1 vs. 7.8%, obesity (body-mass index > or = 25 Kg/m2) in 20.7 vs. 33.0%, and truncal obesity (waist:hip > 0.9) in 54.7 vs. 54.4%. In women, tobacco use was in 18.7 vs. 20.5%, leisure time physical inactivity in 72.4 vs. 75.3%, hypertension in 36.9 vs. 33.7%, diabetes history in 1.0 vs. 7.3%, obesity in 19.9 vs. 39.4%, and truncal obesity (waist:hip > 0.8) in 70.1 vs. 69.2%. In men, high total cholesterol > or = 200 mg/dl was in 24.6 vs. 37.4%, high LDL cholesterol > or = 130 mg/dl in 22.1 vs. 37.0%, high triglycerides > or = 150 mg/dl in 26.6 vs. 30.6% and low HDL cholesterol < 40 mg/dl in 43.2 vs. 54.9%; while in women these were in 22.5 vs. 43.1%, 28.6 vs. 45.1%, 28.6 vs. 28.7% and 45.9 vs. 54.2% respectively. In the second study there was a significant increase in diabetes, obesity, hypertension (men), total- and LDL cholesterol and triglycerides and decrease in HDL cholesterol (p < 0.05). In the first study with increasing educational status a significant increase of obesity, total cholesterol, LDL cholesterol and triglycerides and decrease in smoking was observed. In the second study increasing education was associated with decrease in smoking, leisure-time physical inactivity, total and LDL cholesterol, and triglycerides and increase in obesity, truncal obesity and hypertension (Least-squares regression p < 0.05). Increase in smoking, diabetes and dyslipidaemias was greater in the less educated groups.

CONCLUSIONS

Significant increase in coronary risk factors--obesity, diabetes, total-, LDL-, and low HDL cholesterol, and triglycerides is seen in this urban Indian population over a seven year period. Smoking, diabetes and dyslipidaemias increased more in low educational status groups.

Influence of total cholesterol levels on long-term mortality in coronary heart disease: a reappraisal

To examine the prognostic significance of total cholesterol levels at baseline in subjects with stable coronary heart disease, 605 patients with stable coronary heart disease were enrolled; 45 of these did not meet inclusion criteria, 41 were lost to follow-up and 40 opted for coronary bypass surgery. Data of the remaining 479 (389 males, 90 females) were analysed. There were 102 males in group I (cholesterol < 200 mg/dL), 187 in group II (cholesterol 200-239 mg/dL), and 100 in group III (cholesterol > or = 240 mg/dL) and 49 females in group I and 41 in group II. The groups were evenly matched for age and numbers with stable angina or survivors of myocardial infarction. Proportion of smokers, hypertensives, diabetics or obese was also similar (p > 0.05). Mean follow-up in years in men was 6.82 +/- 3.15 in group I, 6.37 +/- 3.11 in group II and 6.81 +/- 2.84 in group III while in women it was 6.95 +/- 2.84 in group I and 7.03 +/- 2.58 years in group II and was not different in various groups (p > 0.05). The overall cardiovascular mortality in various groups in men was 20.6 percent in group I, 28.9 percent in group II and 23.0 percent in group III and in women it was 14.3 percent in group I and 22.0 percent in group II. The crude mortality rate was 2.51 percent per year in males and 1.77 percent per year in females. Actuarial survival at end of seven years in males was 0.76 +/- 0.05 in group I, 0.67 +/- 0.04 in group II, and 0.67 +/- 0.05 in group III and in females it was 0.85 +/- 0.05 in group I and 0.73 +/- 0.09 in group II. The cumulative hazard rates per 1000 person- year follow-up in group I, II and III in males were, at age less than 50 years: 5.4 +/- 5, 19.8 +/- 7, 17.4 +/- 8; at 50-59 years: 23.8 +/- 11, 38.5 +/- 9, 39.8 +/- 13; and at 60 years and over: 76.9 +/- 20, 112.6 +/- 20, 108.2 +/- 28, respectively (p < 0.001 on comparison of group I with groups II and III). In females the trends were not significant. Total cholesterol levels at baseline predict long-term cardiovascular mortality in men with stable coronary heart disease.

Prevalence and determinants of coronary heart disease in a rural population of India

BACKGROUND

The prevalence and determinants of coronary heart disease (CHD) have been inadequately studied in rural areas of developing countries.

METHODS

Entire communities were surveyed in randomly selected villages in Rajasthan, India. A physician-administered questionnaire, physical examination, and electrocardiogram (ECG) were performed on 3148 adults > or = 20 years of age (1982 males, 1166 females). Fasting blood samples for determination of lipids were obtained from 202 males and 98 females. Prevalence of coronary risk factors--smoking, hypertension, sedentary life-style, obesity, and hypercholesterolemia--was determined. CHD was diagnosed on basis of past documentation, response to WHO-Rose questionnaire, or changes in ECG. Three methods were used: (a) documentation, history, and ECG criteria, (b) ECG-Q, ST, or T changes, and (c) presence of Q waves.

RESULTS

Coronary risk factors: smoking was present in 51% males and 5% females, hypertension (> or = 140/90 mmHg) in 24% males and 17% females, hypercholesterolemia (> 200 mg/dl) in 22%, diabetes history in 0.2%, and irregular physical activity or sedentary habits in 85%. Other risk factors were lack of formal education in 44%, obesity (body-mass index > or = 27 kg/m2) in 6% and truncal obesity (waist-hip ratio > or = 0.95) in 5%. The prevalence of CHD (clinical + ECG criteria) was 3.4% in males and 3.7% in females. According to ECG criteria only, it was 2.8% in males and 3.3% in females and according to Q-waves only, it was 1.6% in males and 0.9% in females. Multivariate logistic regression analysis showed that age and smoking in males and age and systolic blood pressure in females were associated with higher prevalence of Q-wave CHD. In males, higher educational level and prayer habit were associated with lower prevalence.

CONCLUSIONS

Prevalence of CHD in this rural community is higher than in previously reported Indian studies. Smoking, hypertension, and sedentary lifestyle have high prevalence. Significant determinants of CHD are increasing age and smoking while education and prayer-habit are protective.

Smoking and alcohol intake in a rural Indian population and correlation with hypertension and coronary heart disease prevalence

3148 persons (1982 males and 1166 females) aged more than 20 years in a cluster of three villages were examined. The overall prevalence of smoking was 51% in males (n = 1006) and 5% in females (n = 54). Among male smokers there were 26% light smokers (< or = 5 bidis/day), 51% moderate smokers (6-20/day) and 17% heavy smokers (> 20 day) and in females there were 54% light smokers, 41% moderate smokers and 5% heavy smokers. Smokers were less educated and had higher prevalence of work-related physical activity and alcohol intake. There was a higher prevalence of hypertension and of ECG Q-waves in male smokers. Regular alcohol intake was seen in 19% males (n = 377) and in 2% females (n = 26). Among males there were 43% light drinkers (< or = 28 gm ethanol/day), 32% moderate drinkers (28-56 gm ethanol/day) and 5% heavy drinkers (> 56 gm ethanol/day). Although this group had a higher prevalence of hypertension there was an insignificant difference in CHD prevalence and a significantly lower prevalence of ECG Q-waves. Subgroup analysis has also been performed taking non-smoker-non-alcohol consuming group as controls. It was found that group which comprised of smokers-non-alcohol consumers had a significantly higher prevalence of hypertension and of ECG Q-waves. Alcohol intake-smoker group had a significantly higher prevalence of hypertension. The habits of smoking and alcohol consumption are widely prevalent among males in this rural community. Smoking and alcohol-intake, both individually and collectively, are related to higher prevalence of hypertension as well as CHD. While the prevalence of hypertension is more among the alcohol consumers, smokers have a higher prevalence of CHD.

Coronary heart disease and coronary risk factor prevalence in rural Rajasthan

To determine the prevalence of coronary risk factors and coronary heart disease (CHD) in rural Rajasthan, 1150 randomly selected individuals in a cluster of villages in central Rajasthan have been studied. These included 805 men and 345 women. The prevalence of various coronary risk factors in the whole group were: Smoking 488 (42.4%); Diabetes (history): 5(0.4%); Alcohol intake: 146 (12.7%); Sedentary lifestyle: 797 (69.3%); Stressful life events: 48 (4.2%); Hypertension (BP > or = 140/90) 152 (13.2%); obesity (BMI > or = 27 Kg/M2): 194 (10.9%); and Truncal obesity (waist:hip > or = 0.93): 20.8%. The overall prevalence of CHD was 46.1/1000. Patients with CHD had a higher prevalence of male sex (67.9 vs 51.5%); educated persons (30.2 vs 28.8%); businessmen (13.2 vs 10.2%); smoking (47.2 vs 40.5%); sedentary lifestyle (75.5 vs 62.3%); stressful life events (7.5 vs 4.8%); and hypertension (26.4 vs 14.8%). On the other hand, persons without CHD had higher prevalence of alcohol intake (10.8 vs 7.5%); regular prayers (23.1 vs 22.6%); physically active lifestyle (37.7 vs 24.5%); obesity (13.6 vs 6.9%), and truncal obesity (21.0 vs 20.0%). The following risk factors emerged significant on statistical analysis (Odds ratio, 95% confidence intervals): male sex (1.99, 1.04 to 3.7); hypertension (2.04, 1.01 to 4.09); male smokers (1.80, 1.28 to 4.09); and sedentary lifestyle (1.86, 1.01 to 3.59). This study shows a low prevalence of CHD in rural population which is however more than previously reported studies from India.

Prognostic significance of radiographic cardiomegaly in patients with coronary heart disease

To define the long term prognosis in patients with coronary heart disease (CHD) we have used criteria of radiographic cardiomegaly supplemented by M-mode echocardiography. 74 patients (Group A) with CHD and cardiomegaly were seen from 1980 to 1983 and have been compared to 121 patients (Group B) with normal cardiac size and prior myocardial infarction. Patients in Group A were defined by radiographic cardiomegaly with cardio-thoracic ratio of 0.50 or more. The groups were matched for age, sex and major coronary risk factors like hypertension, total cholesterol levels, smoking and diabetes. The echocardiographic diastolic left ventricular internal dimension of 6.16 +/- 0.34 cm was significantly more in Group A as compared to 4.94 +/- 0.26 cm in Group B (t = 2.03, p < 0.05). Actuarial analysis indicates that mortality or surgical option is significantly higher in patients with cardiomegaly (Logrank test = 59.72, p < 0.001) and the mortality is significantly more during the initial years. Thus, radiographic cardiomegaly indicates a bad prognosis in patients with CHD.

Influence of cessation of smoking on long term mortality in patients with coronary heart disease

Cessation of smoking in patients with coronary artery disease (CAD) has shown variable results. The long term mortality in patients of coronary heart disease (CHD) who quit smoking following diagnosis of their disease has been variable. We have analysed the long term effects of cessation of smoking on mortality in a cohort of 173 patients with CAD and compared the mortality of this group with 299 nonsmokers and 52 current smokers. The baseline data were identical for major risk factors like age, hypertension, diabetes, cholesterol levels, and congestive heart failure among the three groups (p > 0.1). There were more patients with previous myocardial infarction in past (38.7%) and current smokers (40.4%) than among nonsmokers (25.4%). All patients were followed for a period extending upto 11 years. The mean duration of follow up was 6.81 +/- 2.95 years in non-smokers, 5.98 +/- 2.94 years in exsmokers, and 6.32 +/- 3.44 years in current smokers. Actuarial analysis shows that overall mortality was significantly more among exsmokers than nonsmokers (Logrank test = 3.72, 1p < 0.05). The exsmokers showed similar mortality as current smokers during the first three years of follow up (Logrank test = 1.10, 1p < 0.1); but afterwards the mortality was significantly less in exsmokers than in current smokers (Logrank test = 6.29, 1p < 0.025). However, the overall mortality was lowest in nonsmokers when compared to that of exsmokers and current smokers (Logrank test = 3.92, p < 0.05). The total mortality was 28.1% in nonsmokers, 32.4% in exsmokers, and 46.2% in current smokers. The incidence of sudden death was, however, similar in all the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Induction of myocardial ischaemia by mental stress in coronary heart disease

To define the importance of mental stress in the genesis of myocardial ischaemia in patients with coronary heart disease, we studied 50 cases in whom ischaemia was provoked by a variety of mental stress tasks: arithmetic calculations, reading aloud and emotionally arousing speech. The haemodynamic responses were compared to those induced by exercise stress tests in 38 of these patients. Thirty four of the 50 patients tested (68%) developed electrocardiographic evidence of ischaemia during mental stress tasks as compared to 29 to 38 patients (76.3%) undergoing treadmill stress test (p > 0.05). The personally relevant emotionally arousing speech task caused more frequent changes as compared to maths and reading tasks (p < 0.01), although reading task provoked more ischaemia than maths task (p < 0.01). The magnitude of ischaemic changes was similar for emotionally arousing speech and treadmill test. On comparison of haemodynamic changes in 38 patients in whom both exercise and speech tasks were performed, it was seen that ischaemic changes occurred at lower heart rates (p < 0.01), lower peak systolic blood pressure (p < 0.01) and a lower double product (p < 0.01) during emotionally arousing speech task than during treadmill stress test.

Influence of mild to moderate treated hypertension on 9-11 year mortality in patients with pre-existing coronary heart disease

Hypertension is a known risk factor in the genesis of coronary artery disease. However, the effect of pre-existing hypertension on the long-term mortality in patients with established coronary heart disease is not clear. The present cohort study analysed the influence of baseline mild to moderate treated hypertension in cases of known coronary heart disease with cardiac mortality as end point. Data from a cohort of 511 patients including 266 normotensives and 245 controlled hypertensives was analysed over a follow-up period of 9 to 11 years. The baseline data were identical regarding other major risk factors like age, gender, smoking, diabetes, cholesterol levels and congestive heart failure on univariate analysis. There were more cases of myocardial infarction in the normotensive group. The number of patients receiving beta-blockers or aspirin were similar in both groups. However, more patients in the hypertensive group received nifedipine. Actuarial analysis of survival showed that mortality was the same in both groups with an overall cardiac mortality of 65 (26.5%) in the hypertensive group and 86 (32.3%) in the normotensive group (P greater than 0.1). The survival curves also showed no significant difference in mortality at any point in time (logrank test = 2.37, P greater than 0.1). Analysis of mortality after adjusting for myocardial infarction at first presentation also showed no significant difference. These data indicate that in patients with coronary heart disease the presence of mild to moderate hypertension does not add to the risk of cardiac mortality.

Long term follow up study of prognostic significance of exercise duration during treadmill stress test in patients with stable coronary heart disease

Treadmill stress tests provide useful noninvasive prognostic information in patients with coronary heart disease (CHD). The present study has prospectively analysed the long term prognostic value of exercise tolerance as measured by exercise time during treadmill stress test in 335 consecutive patients with stable CHD. 161 had exercise time of 6 minutes or less (mean 4.58 +/- 1.54 minutes) on a modified protocol (Group A) and 174 had exercise time of more than 6 minutes (mean 9.30 +/- 0.74 minutes)(Group B). Both groups were matched for major coronary risk factors (hypertension, smoking, diabetes and cholesterol levels) and type of drug therapy (betablockers, nifedipine, diuretics and aspirin). The patients have been followed up for upto 9 years with a mean of 6.28 +/- 2.99 years (Group A) and 7.87 +/- 1.98 years (Group B). Actuarial analysis shows that the overall survival after dropout due to death or coronary artery bypass surgery was significantly lower in group A [dropouts = 66 (41.0%)] than in Group B [dropouts = 19 (10.9%)] (Logrank test = 39.94, p < 0.001). The mortality was significantly higher in Group A with 58 deaths (36.0%) as compared to Group B with 16 deaths (9.2%) (x2 = 34.98, p < 0.001). The crude death rate was 5.73% per year in Group A as compared to 1.17% per year in Group B. The incidence of sudden deaths was also higher in Group A with 28(17.4%) instances as compared to 5(2.9%) in Group B (x2 = 19.85, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Total cholesterol and mortality in patients with pre-existing coronary artery disease

BACKGROUND

A positive correlation exists between serum cholesterol levels and cardiovascular mortality. However, the role of serum cholesterol in persons with pre-existing coronary artery disease is not clear.

METHODS

A cohort of 524 patients with coronary artery disease was divided into four groups based on the total serum cholesterol values. Group I consisted of 68 patients with cholesterol levels of 200 mg/dl or less; Group II of 116 patients with cholesterol levels between 201 and 220 mg/dl; Group III of 187 patients with levels between 221 and 240 mg/dl and Group IV of 153 patients with cholesterol levels greater than 240 mg/dl.

RESULTS

Actuarial survival analysis over an 11-year follow up did not show any overall difference in mortality between these groups (Logrank test statistic = 1.89, p > 0.1). Analysis after adjustment of the data also showed that mortality rates were not different (chi (2) = 4.73, p > 0.05). Hazard function analysis indicated that death rates per thousand person years of follow up were 49.97 +/- 8.4 in Group I, 41.38 +/- 8.4 in Group II, 55.39 +/- 4.4 in Group III and 45.38 +/- 6.4 in Group IV. These were also not statistically significant. Comparison of mortality rates in patients with angina pectoris and past myocardial infarction also showed similar results.

CONCLUSION

Total serum cholesterol levels do not influence long term survival in patients with pre-existing coronary artery disease.

Mitral valve prolapse: two dimensional echocardiography reveals a high prevalence in three to twelve year old children

The prevalence of mitral valve prolapse (MVP) appears to be age related, MVP being commoner in children as compared to adults. This suggests that asymptomatic MVP may be most frequent in children who are very young. In this study, to better define the prevalence of MVP in young children, we used two dimensional echocardiography and prospectively surveyed 213 healthy urban school children between 3 and 12 years of age. MVP was diagnosed when prolapse of mitral leaflet/s was demonstrated by both two-dimensional and M-mode echocardiography at parasternal long-axis views. Overall, MVP was found in 28 of 213 (13.1%) children. MVP was similarly prevalent in all age groups studied (3-5.9 years: 13 of 83 (13.5%); 6-8.9 years: 9 of 71 (11.2%); and 9-12 years: 6 of 31 (16.2%) children; Chi square = 0.57, p greater than 0.5). Univariate analysis showed that the prevalence of MVP was independent of sex, birth weight, resting heart rate and systolic or diastolic blood pressure. A mid systolic murmur was present in 50.6% of the children although it correlated with echocardiographic diagnosis of MVP in only 39.3%. The left ventricular size or wall thickness and mitral EF and DE slopes were similar in children either with or without MVP. Our results indicate that asymptomatic MVP is frequent in children upto 12 years of age. As a diagnostic test of MVP, presence of apical systolic murmur is considerably inferior to echocardiography. No morphological left ventricular correlates were identified in MVP.

Prognostic value of profound ST segment depression during treadmill stress test in coronary heart disease: nine years follow-up study

To define the prognostic significance of profound ST segment depression (greater than or equal to 3mm) during exercise test, 106 patients of definite coronary heart disease enrolled in a prospective study were followed for up to 9 years. Group A (56 patients) had profound (greater than or equal to 3mm) ST segment depression (3.56 +/- 0.74mm) and Group B (50 patients) had less than 3mm ST segment depression (1.23 +/- 0.35mm, P less than 0.01) during treadmill testing. Group A patients tolerated exercise for a lesser duration in comparison to group B patients (7.22 +/- 3.35 vs. 10.18 + 4.07 minutes, p less than 0.01). At the end of the study, 21 (37.5%) group A patients either died or underwent coronary artery bypass surgery as compared to 8 (16.0%) group B patients (p = 0.02). The difference in the incidence of cardiac deaths between the two groups was not statistically significant (19.6% in group A and 14.0% in group B). However, sudden deaths were significantly more common in group A as compared to group B patients (10 of 11 (90.9%) vs 4 of 7 (57.1%), p = 0.02). These data suggest that profound ST segment depression (greater than 3mm) during treadmill stress test indicates an adverse long term prognosis with the risk in particular, of sudden cardiac death.

Identification of a phosphoenolpyruvate:fructose 1-phosphotransferase system in Azospirillum brasilense

An inducible phosphoenolpyruvate:fructose phosphotransferase system has been detected in Azospirillum brasilense, which requires a minimum of two components of the crude extracts for activity: (i) a soluble fraction (enzyme I) and (ii) a membrane fraction (enzyme II). The uninduced cells neither show any uptake of fructose nor express activity of either of these two enzyme fractions. C-1 of fructose is the site of phosphorylation. This phosphotransferase system does not accept glucose as a substrate for phosphorylation.

A new type of x-ray absorption spectrometer

A single-crystal spectrometer for x-ray absorption and emission with a microfocus x-ray source has been set up so that the divergent rays from the source can be analyzed over a wide range of Bragg angles with a high degree of resolution. The covered energy interval depends upon the exposed width of the crystal and the geometrical setup. Preliminary experiments are presented to show the effectiveness of the spectrometer.