Low-density lipoprotein cholesterol estimation by a new formula in Indian population

BACKGROUND

Estimation of low-density lipoprotein cholesterol is crucial in the management of ischemic heart disease patients. Low-density lipoprotein cholesterol is routinely calculated in laboratories world over by applying Friedewald formula for logistic reasons. We derived a new formula based on multiple regression approach.

METHODS

Lipid profiles were done on blood samples of 2008 patients. In initial 1000 patients, low-density lipoprotein cholesterol was estimated by a direct method and also by Friedewald formula. By applying linear regression methods on the data of direct estimation method, a new formula was obtained and the accuracy of this new formula was validated in the next 1008 patients.

RESULTS

The mean low-density lipoprotein cholesterol was 116+/-41.5 mg/dl (3.02+/-1.08 mmol/l) measured by direct low-density lipoprotein cholesterol assay and that calculated by Friedewald formula was 119+/-46 mg/dl (3.09+/-1.2 mmol/l) for the initial 1000 patients. Low-density lipoprotein cholesterol measured by direct low-density lipoprotein cholesterol assay and calculated from Friedewald formula showed good correlation (r = 0.88), however, there was minimal overestimation by the Friedewald formula. The correlation improved between direct low-density lipoprotein cholesterol and calculated low-density lipoprotein cholesterol after excluding the patients with triglycerides more than 350 mg/dl (r = 0.92). The mean low-density lipoprotein cholesterol measured by the direct assay and by new formula in the next 1008 patients was 117+/-40 mg/dl (3.04+/-1.04 mmol/l) and 113.7+/-37 mg/dl (2.96+/-0.96 mmol/l), respectively with very good correlation (r = 0.97) between them.

CONCLUSIONS

The new formula derived from multiple linear regression analysis appears to be more accurate than Friedewald formula in Indian population.

Prevalence of tuberculous lymphadenitis in children in Wardha district, Maharashtra State, India

SETTING

Rural area of Wardha district, Maharashtra State, Central India.

OBJECTIVE

To determine the prevalence of tuberculous lymphadenitis in children aged 0-14 years in the study area and to assess factors that may contribute towards the prevalence.

DESIGN

House to house survey of a population of 23,229 in 35 neighbouring villages with 7900 children aged 0-14 years from May 1993 to May 1994 and from March 1995 to February 1996.

RESULTS

The prevalence of tuberculous lymphadenitis/1000 children was 4.43. The maximum prevalence was in the 5-9 years age group. The prevalence was 34 times higher in children with positive family history of tuberculosis than in those without a history. There was an association between prevalence and the living standards of the children, with a higher prevalence in families that belonged to an underprivileged social class living in thatched, improvised houses. Multiple cervical lymph nodes >2 cm and with matting and fluctuation were found to be characteristic clinical features.

CONCLUSION

The prevalence of peripheral lymphadenopathy was 27.2/1000 children and that of tuberculous lymphadenitis was 4.43/1000. Positive history of contact in the family was a significant epidemiological indicator of tuberculous glands.

Apolipoprotein C3 SstI polymorphism in the risk assessment of CAD

Various population studies have reported the association of rare S2 allele of apolipoprotein C3 (APOC3) SstI polymorphism with hypertriglyceridemia (HTG) and coronary artery disease (CAD). We were the first to report an association of S2 allele with high triglyceride (TG) levels in healthy volunteers from Northern India. Since HTG is suggested to be a predominant risk factor for CAD among Indians, we have elucidated the relationship of APOC3 SstI polymorphism with the lipid profile and CAD. A total of 158 patients with > or = 70% stenosis in one or more coronary artery (angiographically proven CAD patients), 35 subjects with < 70% stenosis (NCAD) and 151 normal controls (free of heart disease) from Northern plains of India were recruited in the study. DNA samples were analyzed by polymerase chain reaction (PCR) followed by SstI digestion. Lipid profile was estimated by enzymatic kit. We found a strong association of S2 allele with high TG levels, which was more significant in patients. Prevalence of S2 allele in normal controls and CAD patients were comparable, despite the fact that mean TG level was significantly higher in patients. A greater insight into this observation revealed that the prevalence of high TG, if not coupled with other risk factors (like high total cholesterol, low HDL), was comparable in patients and controls. Thus, our study reveals that rare S2 allele may be employed as a susceptibility marker for high TG. However, high TG or S2 allele alone may not contribute to the etiology of CAD.

Modeling bacterial species abundance from small community surveys

Taxon abundance patterns are a central focus in evolution and ecology, providing the basic architecture of natural assemblages and potential clues to their formative processes. To better interpret species abundance patterns in natural microbial communities, we examined the consequences of three fundamental types of abundance patterns--uniform, geometric, and lognormal distributions. Theoretical communities were constructed based on the three pattern types with 2000 to 20,000 species and 10(7) to 10(10) individuals. The "dominant" species (species 1) among models that differed only in pattern type generally varied in abundance by 1 to 3 orders of magnitude. At the extremes among all the models examined, the dominant species comprised as much as 16% and as little as 0.005% of the total community. Analysis of the models and comparison with seven published surveys suggests that entire soil bacterial communities do not routinely exhibit Preston's cannonical subset of lognormal distributions. Use of the models to evaluate survey limitations showed that common diversity indices are generally sensitive to sample size over the range (50 to 200 clones) commonly used for microbial communities, emphasizing the need to compare surveys of similar size. The results collectively demonstrate that uniform, geometric, and lognormal distributions have profoundly different experimental and ecological consequences. Further, defined abundance models provide a simple quantitative tool for evaluating abundance patterns in clone libraries (even small ones) from natural communities.

Enhanced acceleration of injected electrons in a laser-beat-wave-induced plasma channel

Enhanced energy gain of externally injected electrons by a approximately 3 cm long, high-gradient relativistic plasma wave (RPW) is demonstrated. Using a CO2 laser beat wave of duration longer than the ion motion time across the laser spot size, a laser self-guiding process is initiated in a plasma channel. Guiding compensates for ionization-induced defocusing (IID) creating a longer plasma, which extends the interaction length between electrons and the RPW. In contrast to a maximum energy gain of 10 MeV when IID is dominant, the electrons gain up to 38 MeV energy in a laser-beat-wave-induced plasma channel.

Nonresonant beat-wave excitation of relativistic plasma waves with constant phase velocity for charged-particle acceleration

The nonresonant beat-wave excitation of relativistic plasma waves is studied in two-dimensional simulations and experiments. It is shown through simulations that, as opposed to the resonant case, the accelerating electric fields associated with the nonresonant plasmons are always in phase with the beat-pattern of the laser pulse. The excitation of such nonresonant relativistic plasma waves is shown to be possible for plasma densities as high as 14 times the resonant density. The density fluctuations and the fields associated with these waves have significant magnitudes, facts confirmed experimentally using collinear Thomson scattering and electron injection, respectively. The applicability of these results towards eventual phase-locked acceleration of prebunched and externally injected electrons is discussed.

Study of apolipoproteinc3 Sstl polymorphism in healthy volunteers from Northern India

Several studies including a small case-control (hypertriglyceridemic/normotriglyceridemic individuals) study by us revealed close association between rare S2 allele ofAPOC3 Sstl polymorphism and hypertriglyceridemia. With the understanding that Asian Indians are highly vulnerable to the adverse effects of hypertriglyceridemia, we extended the investigation and studied the frequency distribution of this polymorphism in 216 healthy volunteers from Northern plains of India. We found that more than 50% of the study population had one or two S2 allele. This may suggest that a larger fraction of this population is genetically predisposed to hypertriglyceridemia.

Spectrum of congenital surgical malformations in newborns

A prospective study to detect the frequency and distribution of congenital surgical malformations in a rural hospital setting in Maharashtra was carried out. A total of 3000 consecutive births over a 9-month period was included and the frequency of congenital malformations was 21.1 per 1000 births. Stillbirths were associated with a higher incidence of malformations (14.5%) as compared to live births (1.8%). The commonest systems affected were the gastro-intestinal tract and the genito-urinary tract (20.4% each) followed by the central nervous system (17.3%). Among the various possible risk factors studied, a higher incidence of congenital malformations was associated with increasing maternal age (> 35 years), higher gravida mothers (> G4), parental consanguineous marriages, previous history of abortions, maternal hypertension, etc.

Apolipoprotein C3 SstI polymorphism and triglyceride levels in Asian Indians

BACKGROUND

A close association between Sst I polymorphism in the 3' untranslated region of the apolipoproteinC3 (APOC3) gene and levels of plasma triglycerides (TG) had been reported by different investigators. Hypertriglyceridemia(HTG) is a known risk factor for coronary artery disease (CAD) in the context of Asian Indians. We conducted a study on the relationship between APOC3 SstI polymorphism (S1S1, S1S2 and S2S2 genotypes) and plasma TG levels in a group of 139 male healthy volunteers from Northern India.

METHODS

DNA samples were analyzed by polymerase chain reaction (PCR) followed by SstI digestion. Digested PCR products were run on 3% agarose gel and visualized by ethidium bromide staining.

RESULTS

Rare S2 allele was highly prevalent in our study population (0.313) as compared to the Caucasians (0.00-0.11). The genotypic distribution was in agreement with Hardy-Weinberg equilibrium. S2 allele was almost two times more prevalent in the HTG group (N = 34) as compared to NTG group (N = 105) (p = 0.001). Multiple logistic regression revealed S1S2 individuals had age-adjusted odds ratio of 2.43 (95%CI = 0.99-6.01, p = 0.054) and S2S2 had 9.9 (95%CI = 2.66-37.29, p = 0.0006) for developing HTG in comparison to S1S1 genotype.

CONCLUSIONS

Our study shows a significant association between rare S2 allele and HTG in Asian Indians.

Efficient shortening of self-chirped picosecond pulses in a high-power CO(2) amplifier

We report a factor-of-6 shortening of the 240-ps (FWHM) pulses in a triple-pass, 2.5-atm CO(2) amplifier. This technique is based on the self-phase modulation of a 10-mum pulse in a plasma after the first pass of amplification, followed by narrowing of this chirped pulse during further amplification. Subsequently, strong power broadening provides the necessary bandwidth to amplify 40-ps pulses to terawatt power levels.

Percutaneous transseptal mitral commissurotomy in pregnant women with critical mitral stenosis

BACKGROUND

Percutaneous transseptal mitral commissurotomy has been successfully performed in selected pregnant patients with severe symptomatic mitral stenosis. Its safety and efficacy needs to be evaluated in a large number of cases.

METHODS AND RESULTS

Percutaneous transseptal mitral commissurotomy was performed in 85 severely symptomatic (New York Heart Association functional class III or IV) pregnant women aged 22.7+/-4.1 years (range 18-39 years) with critical mitral stenosis at 24.8+/-4.7 weeks (range 20-34 weeks) of gestation. Percutaneous valvotomy was performed using a flow-guided Inoue balloon in all the patients. The procedure was considered successful in 80 (94%) patients. The hemodynamic mean end-diastolic gradient decreased from 26.7+/-6.8 mm Hg (range 16-35 mmHg) to 4.5+/-3.8 mmHg (range 0-14 mmHg) (p<0.001). The mean diastolic gradient decreased from 29.1+/-9.1 mmHg (range 18-38 mmHg) to 7.2+/-4.1 mmHg (range 4.1-18 mmHg) (p<0.001). The mean mitral valve area assessed by echocardiography increased from 0.75+/-0.5 cm2 (range 0.4-1.0 cm2) to 2.0+/-0.5 (range 1.0-2.7 cm2) (p<0.001). The mean fluoroscopy time was 3.6+/-3.2 minutes. The results of the mitral valvotomy were considered suboptimal in 4 patients. Mitral regurgitation increased by 1 grade in 16 patients and more than 2 grades in 2 patients. One patient developed pericardial tamponade during the procedure and was managed by catheter drainage. Percutaneous mitral valve dilatation was then successfully performed in this patient. No fetal abortion occurred after the procedure.

CONCLUSIONS

The results of this study indicate that percutaneous transseptal mitral commissurotomy is a safe and effective procedure for severe symptomatic mitral stenosis in pregnancy.

Autonomic studies in hypertensive patient with unusual sexual dysfunction: response to reserpine

The authors examined a 48-year-old man with a history of hypertension (6 years) and a history of erection and ejaculation during cold exposure and confrontation with fear (20 years). Exposing the foot to cold water induced ejaculation in 10 seconds. A variety of antihypertensive medications resulted in control of hypertension, without improvement in ejaculatory dysfunction. Similarly, prazosin controlled the blood pressure, but not the episodes of ejaculation. Treatment with reserpine resulted in gradual reduction in blood pressure and an improvement in ejaculatory dysfunction.

Retardation of coronary atherosclerosis with yoga lifestyle intervention

BACKGROUND

Yoga has potential for benefit for patients with coronary artery disease though objective, angiographic studies are lacking.

MATERIAL AND METHODS

We evaluated possible role of lifestyle modification incorporating yoga, on retardation of coronary atherosclerotic disease. In this prospective, randomized, controlled trial, 42 men with angiographically proven coronary artery disease (CAD) were randomized to control (n = 21) and yoga intervention group (n = 21) and were followed for one year. The active group was treated with a user-friendly program consisting of yoga, control of risk factors, diet control and moderate aerobic exercise. The control group was managed by conventional methods i.e. risk factor control and American Heart Association step I diet.

RESULTS

At one year, the yoga groups showed significant reduction in number of anginal episodes per week, improved exercise capacity and decrease in body weight. Serum total cholesterol, LDL cholesterol and triglyceride levels also showed greater reductions as compared with control group. Revascularisation procedures (coronary angioplasty or bypass surgery) were less frequently required in the yoga group (one versus eight patients; relative risk = 5.45; P = 0.01). Coronary angiography repeated at one year showed that significantly more lesions regressed (20% versus 2%) and less lesions progressed (5% versus 37%) in the yoga group (chi-square = 24.9; P < 0.0001). The compliance to the total program was excellent and no side effects were observed.

CONCLUSION

Yoga lifestyle intervention retards progression and increases regression of coronary atherosclerosis in patients with severe coronary artery disease. It also improves symptomatic status, functional class and risk factor profile.

Apolipoprotein(a) polymorphism and its association with plasma lipoprotein(a) levels: a north Indian study

Elevated levels of lipoprotein(a) has been regarded as an independent risk factor for coronary, peripheral and cerebral atherosclerosis. The enormous intra-personal variation in the plasma concentration of lipoprotein(a) is almost entirely controlled by the apolipoprotein(a) i.e. gene locus on the chromosome 6q 26-27. The apolipoprotein(a) molecule is highly polymorphic and is known to exist in multiple, genetically determined isoforms. These polymorphisms may be responsible for difference in promoter activity, variable size of apolipoprotein(a) and thereby variation in plasma lipoprotein(a) concentration. We studied the effect of two types of polymorphisms, (i) variation in length of the pentanucleotide repeat in the 5' flanking region starting -1373 bp upstream of AUG codon, and (ii) the Kringle-4 type 2 size polymorphism, on plasma lipoprotein(a) levels in North Indian population. The study group consisted of 88 angiographically assessed male coronary artery disease patients (age range 30-70 years) and 83 age- and sex-matched healthy controls. The pentanucleotide repeat polymorphism was analysed using polymerase chain reaction. In all, 8/11 pentanucleotide repeat isoforms were observed. Using SDS-agarose gel electrophoresis and immunoblotting isoforms having 12-50 Kringle-4 type 2 repeats were detected. Our study indicates a strong association of elevated plasma lipoprotein(a) concentration with coronary artery disease. An inverse correlation was seen between lipoprotein concentration and isoform size for both the pentanucleotide repeat polymorphism and the Kringle-4 type 2 polymorphisms; statistically significant difference (p = 0.001) was, however, observed only for the later.

Generation of 160-ps terawatt-power CO(2) laser pulses

We have developed a three-stage CO(2) master-oscillator-amplifier system that produces 1.1 TW of peak power. The system generates 170 J of energy in a diffraction-limited 160+/-10ps pulse on the 10P(20) line. We also report the realization of a two-wavelength terawatt-peak-power CO(2) laser that can be tuned to an arbitrary pair of lines. A two-stage semiconductor switching system driven by a picosecond-pulse Nd:YAG laser was used to slice a short, low-power 10.6-mum pulse for amplification. A simple plasma shutter helped to compensate for gain narrowing in a final three-pass amplifier and to shorten the pulse.