Saturated fat-rich diet enhances selective uptake of LDL cholesteryl esters in the arterial wall

Plasma LDL levels and atherosclerosis both increase on a saturated fat-rich (SAT) diet. LDL cholesterol delivery to tissue may occur via uptake of the LDL particles or via selective uptake (SU), wherein cholesteryl ester (CE) enters cells without concomitant whole-particle uptake. It is not known how dietary fats might directly affect arterial LDL-CE uptake and whether SU is involved. Thus, mice that are relatively atherosclerosis resistant (C57BL/6) or susceptible to atherosclerosis (apoE) were fed a chow or SAT diet and injected with double radiolabeled or fluorescent-labeled human LDL to independently trace LDL-CE core and whole-particle uptake, respectively. Our results show that a SAT diet increased contributions of SU to total arterial LDL-CE delivery in C57BL/6 and apoE mice. The SAT diet increased plasma fatty acid and cholesterol levels; cholesterol, but not fatty acid, levels correlated with SU, as did the degree of atherosclerosis. Increased SU did not correlate with arterial scavenger receptor class B type I levels but paralleled increased lipoprotein lipase (LPL) levels and LPL distribution in the arterial wall. These studies suggest that arterial LDL-CE delivery via SU can be an important mechanism in vivo and that dietary influences on arterial LPL levels and atherogenesis modulate arterial LDL-CE delivery, cholesterol deposition, and SU.

Postprandial response to a physiologic caloric load in HIV-positive patients receiving protease inhibitor-based or nonnucleoside reverse transcriptase inhibitor-based antiretroviral therapy

BACKGROUND

Features of the dyslipidemic pattern reported with the use of antiretroviral therapy predict enhanced postprandial lipemia, which is an emerging cardiovascular disease risk factor.

OBJECTIVE

We evaluated the postprandial response to a physiologic, meal-based challenge in HIV-positive subjects without hyperlipidemia.

DESIGN

We measured hourly lipid, lipoprotein, glucose, and insulin concentrations during a 13-h period in 25 nonwhite patients (13 women, 12 men): 13 receiving a protease inhibitor (PI)-based regimen (6 nelfinavir and 7 indinavir) and 12 receiving a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen (6 efavirenz and 6 nevirapine).

RESULTS

Mean fasting HDL-cholesterol concentrations were lower in HIV patients than in healthy subjects without HIV infection matched for age, sex, and ethnicity (z score: -0.81 +/- 0.9; P = 0.0001). Fasting triacylglycerol concentrations were not significantly different between HIV-infected patients and healthy subjects but were higher in PI-treated than in NNRTI-treated patients [median (interquartile range): 144 (110-191) and 89 (62-135) mg/dL; P = 0.007]. Average daylong triacylglycerol concentrations, but not incremental concentrations, were higher in the PI group than in the NNRTI group [205% (185-248%) and 125% (78-191%); P < 0.05]. For all HIV-positive patients, the fractional triacylglycerol increase was lower after breakfast than after lunch (20 +/- 18% and 42 +/- 40%, respectively; P < 0.04). Insulin concentrations were higher in PI-treated than in NNRTI-treated patients [22.6 (13.1-29.8) and 11.8 (7.1-19.1) microU/mL; P = 0.01] and increased in both groups in response to each meal, whereas glucose concentrations increased only after breakfast.

CONCLUSIONS

Despite baseline differences, incremental triacylglycerol and insulin responses to a physiologic caloric load among HIV-positive patients were not significantly affected by differences in the type of antiretroviral therapy.

Cigarette smoking increases human vitamin E requirements as estimated by plasma deuterium-labeled CEHC

Cigarette smoking (CS) is a well-described oxidant burden in humans. We hypothesized that CS would accelerate alpha-tocopherol (alpha-T) utilization leaving less for metabolite (CEHC) production. After labeled alpha-T consumption (75 mg each of d(3)-RRR-alpha-TAc and d(6)-all-rac-alpha-TAc) by smokers and nonsmokers (n = 10/group), CS increased alpha-T disappearance and decreased plasma and urinary CEHCs. Plasma d(3)/d(6)-alpha-T ratios were approximately 1.4 during supplementation and approximately 2 from days 5 to 17. d(3)/d(6)-alpha-CEHC ratios were on average 0.29 +/- 0.05, confirming that all-rac-alpha-tocopherol is metabolized more efficiently. CEHC may be a good marker of vitamin E status, and smokers may have an increased vitamin E requirement.

Cholesterol-Lowering Benefits of Oat-Containing Cereal in Hispanic Americans

This randomized, controlled trial of cholesterol lowering by an oat bran cereal containing beta glucan vs a corn cereal without soluble fiber in Hispanic Americans was conducted for 11 weeks. One-hundred fifty-two men and women, ages 30 to 70 years, with baseline low-density lipoprotein cholesterol (LDL-C) levels between 120 and 190 mg/dL and triglycerides <400 mg/dL were included. After eating a National Cholesterol Education Program Step 1 diet for 5 weeks, subjects were randomly assigned to the corn or the oat cereal for the next 6 weeks. The daily dose of beta glucan was 3 g. Consumption of oat cereal was associated with a reduction in plasma levels of both total cholesterol (-10.9+/-21.6 mg/dL; -4.5%) and LDL-C (-9.4+/-20.3 mg/dL; -5.3%). Consumption of corn cereal did not affect either total cholesterol (+1.2+/-18.3 mg/dL; 1.1%) or LDL-C (+1.2+/-17.5 mg/dL; 2.2%). Differences between the effects of the two cereals on total cholesterol and LDL-C were significant, P =.0003 and P =.0007, respectively.

Effects of the PPARgamma agonist pioglitazone on lipoprotein metabolism in patients with type 2 diabetes mellitus

Elevated plasma levels of VLDL triglycerides (TGs) are characteristic of patients with type 2 diabetes mellitus (T2DM) and are associated with increased production rates (PRs) of VLDL TGs and apoB. Lipoprotein lipase-mediated (LPL-mediated) lipolysis of VLDL TGs may also be reduced in T2DM if the level of LPL is decreased and/or the level of plasma apoC-III, an inhibitor of LPL-mediated lipolysis, is increased. We studied the effects of pioglitazone (Pio), a PPARgamma agonist that improves insulin sensitivity, on lipoprotein metabolism in patients with T2DM. Pio treatment reduced TG levels by increasing the fractional clearance rate (FCR) of VLDL TGs from the circulation, without changing direct removal of VLDL particles. This indicated increased lipolysis of VLDL TGs during Pio treatment, a mechanism supported by our finding of increased plasma LPL mass and decreased levels of plasma apoC-III. Lower apoC-III levels were due to reduced apoC-III PRs. We saw no effects of Pio on the PR of either VLDL TG or VLDL apoB. Thus, Pio, a PPARgamma agonist, reduced VLDL TG levels by increasing LPL mass and inhibiting apoC-III PR. These 2 changes were associated with an increased FCR of VLDL TGs, almost certainly due to increased LPL-mediated lipolysis.

Studies in humans using deuterium-labeled alpha- and gamma-tocopherols demonstrate faster plasma gamma-tocopherol disappearance and greater gamma-metabolite production

We hypothesized that human plasma alpha- and gamma-tocopherol concentrations reflect differences in their kinetics, especially influenced by gamma-tocopherol metabolism. Vitamin E kinetics were evaluated in humans (n=14) using approximately 50 mg each of an equimolar ratio of d6-alpha- and d2-gamma-tocopheryl acetates administered orally. Mass spectrometry was used to measure deuterated plasma tocopherols, as well as plasma and urinary vitamin E metabolites, alpha- and gamma-carboxyethylhydroxychromans (CEHCs). Plasma d2-gamma-tocopherol fractional disappearance rates (FDR; 1.39+/-0.44 pools/day, mean+/-SD) were more than three times greater than those of d6-alpha-tocopherol (0.33+/-0.11, p<0.001). The d2-gamma-tocopherol half-life was 13+/-4 h compared with 57+/-19 for d6-alpha-tocopherol. Whereas neither plasma nor urinary d6-alpha-CEHC was detectable (limit of detection 1 nmol/L), gamma-CEHC (labeled plus unlabeled) increased from 129+/-20 to 258+/-40 nmol/L by 12 h and returned to baseline by 48 h; at 12 h d2-gamma-CEHC represented 54+/-4% of plasma gamma-CEHC. Women compared with men had a greater d2-gamma-tocopherol FDR (p<0.004) and a greater maximal plasma d2-gamma-CEHC concentration (p<0.02) and CEHC FDR (p<0.007), as well as excreting four times as much d2-gamma-CEHC (p<0.04) in urine. Thus, gamma-tocopherol is rapidly metabolized to gamma-CEHC, and to a greater degree in women than in men, whereas alpha-tocopherol is maintained in the plasma and little is metabolized to alpha-CEHC.

Effect of gender on the manifestations of celiac disease: evidence for greater malabsorption in men

OBJECTIVE

Because celiac disease is a female-predominant disease we investigated the influence of gender on clinical manifestations of the disease in the United States.

MATERIAL AND METHODS

Data were obtained on biopsy-proven adult patients with celiac disease from a database of patients seen between 1981 and 2001 in a University-based referral center. Z scores were calculated to adjust for age, ethnicity and gender using the National Health and Nutrition Examination Survey database as controls.

RESULTS

The cohort consisted of 323 patients (211 F, 112 M). Men had a shorter duration of symptoms than women (p=0.006). There was no gender difference in the age at diagnosis or mode of presentation. Body mass index (BMI), mean hemoglobin and ferritin values were lower in women than in men, but the Z scores for these values were not significantly different, indicating that the differences are physiological. All lipid values were low (negative Z scores). Men had lower total cholesterol (162.0+/-46.5mg/dl) compared to women (181.0+/-40.0mg/dl), p=0.02 and lower Z scores (-1.10+/-1.1) compared to women (-0.71+/-0.9), p=0.04. Men had lower bone density T scores at the radius (p=0.07). Autoimmune diseases were present in 30.7% with a female to male ratio of 1:1, compared to the general population in which 3.2% have autoimmune diseases with a female predominance.

CONCLUSIONS

Most gender differences in celiac disease are physiological. However, men have indirect evidence of greater malabsorption than females and have female-predominant associated diseases when they present with celiac disease.

Scavenger Receptor Class B Type I Mediates the Selective Uptake of High-Density Lipoprotein–Associated Cholesteryl Ester by the Liver in Mice

OBJECTIVE

High-density lipoprotein (HDL) cholesteryl esters (CE) are taken up by liver and adrenals selectively, ie, independent from particle internalization. Class B type I scavenger receptor (SR-BI) mediates this uptake in vitro. The role of SR-BI in HDL metabolism was explored in mice.

METHODS AND RESULTS

Mice with a mutation in the SR-BI gene (SR-BI KO) and wild-type (WT) littermates were used. Mutants had increased HDL cholesterol. HDL was labeled with 125I (protein) and [3H] (CE). After HDL injection, blood samples were drawn and finally the mice were euthanized. In WT, the plasma decay of HDL-associated [3H] is faster compared with 125I and this represents whole-body selective CE uptake. In SR-BI KO, the decay of both tracers is similar, yielding no selective CE removal. In WT liver and adrenals, uptake of [3H] is higher than 125I, showing selective uptake. In SR-BI KO, liver uptake of [3H] and 125I are similar, proposing no selective HDL CE uptake. In SR-BI KO adrenals, selective uptake is reduced; however, even in the absence of SR-BI, this uptake is detected using WT-HDL.

CONCLUSIONS

SR-BI mediates selective uptake of HDL CE by the liver. In adrenals, an alternative mechanism or mechanisms can play a role in selective CE uptake.

Prevalence of disability and handicaps in geriatric population in rural south India

Proportion of aged persons in India is increasing and is expected to be around 70 million by the end of the year 2000. The epidemiological consequences would be increase in the geriatric problems, particularly, impairments, disabilities and handicaps There are not many community-based studies using the International Classification of Impairments, Disabilities and Handicaps (ICIDH). The main objective of this study was to estimate the prevalence of disabled in the elderly population (aged above 60 years) in a district of south India using ICIDH classification. Thirty villages were selected using probability proportional to size linear systematic sampling (PPSLSS) from Villupuram health unit district in Tamilnadu in south India. One hundred and five households were selected from each selected village by using linear systematic sampling. A structured proforma was administered to 974 subjects to obtain information on disability as perceived by rural geriatric population. Visual disability was found to be the most important single preventable disability (56%). Only 33% of persons with visual disability wore spectacles. A decline in social interaction was reported. There was an urgent need to strengthen health care activities related to geriatric health care to improve the quality of life of the elderly population, including care of vision in particular.

{alpha}-Tocopherol disappearance is faster in cigarette smokers and is inversely related to their ascorbic acid status

BACKGROUND

Cigarette smokers have enhanced oxidative stress from cigarette smoke exposure and from their increased inflammatory responses.

OBJECTIVE

The objective of this study was to determine whether cigarette smoking increases plasma alpha-tocopherol disappearance in otherwise healthy humans.

DESIGN

Smokers and nonsmokers (n = 10/group) were supplemented with deuterium-labeled alpha-tocopheryl acetates (75 mg each of d(3)-RRR-alpha-tocopheryl acetate and d(6)-all-rac-alpha-tocopherols acetate) for 6 evenings (days -6 to -1). Plasma alpha-tocopherols, ascorbic acid, uric acid, and F(2alpha)-isoprostanes were measured in blood samples collected on days -6 through 17. The urinary alpha-tocopherol metabolite, alpha-carboxy-ethyl-hydroxy-chroman (alpha-CEHC), was measured on days -6, 0, and 17 in 24-h urine samples.

RESULTS

F(2alpha)-isoprostanes were, on average, approximately 40% higher in smokers than in nonsmokers. On day 0, plasma labeled and unlabeled alpha-tocopherol concentrations were not significantly different between groups. Smoking resulted in faster fractional disappearance of plasma alpha-tocopherol (0.215 +/- 0.011 compared with 0.191 +/- 0.009 pools/d; P < 0.05). Fractional disappearance rates of alpha-tocopherol correlated with plasma ascorbic acid concentrations in smokers (P = 0.021) but not in nonsmokers despite plasma ascorbic acid concentrations that were not significantly different between groups. By day 17, cigarette smoking resulted in lower plasma alpha-tocopherol concentrations and urinary excretion of labeled and unlabeled alpha-CEHC (P < 0.05).

CONCLUSIONS

Cigarette smoking increased alpha-tocopherol disappearance. Greater rates of alpha-tocopherol disappearance in smokers appear to be related to increased oxidative stress accompanied by lower plasma ascorbic acid concentrations. Thus, smokers have an increased requirement for both alpha-tocopherol and ascorbic acid.

Lipoprotein(a): an elusive cardiovascular risk factor

Lipoprotein (a) [Lp(a)], is present only in humans, Old World nonhuman primates, and the European hedgehog. Lp(a) has many properties in common with low-density lipoprotein (LDL) but contains a unique protein, apo(a), which is structurally different from other apolipoproteins. The size of the apo(a) gene is highly variable, resulting in the protein molecular weight ranging from 300 to 800 kDa; this large variation may be caused by neutral evolution in the absence of any selection advantage. Apo(a) influences to a major extent metabolic and physicochemical properties of Lp(a), and the size polymorphism of the apo(a) gene contributes to the pronounced heterogeneity of Lp(a). There is an inverse relationship between apo(a) size and Lp(a) levels; however, this pattern is complex. For a given apo(a) size, there is a considerable variation in Lp(a) levels across individuals, underscoring the importance to assess allele-specific Lp(a) levels. Further, Lp(a) levels differ between populations, and blacks have generally higher levels than Asians and whites, adjusting for apo(a) sizes. In addition to the apo(a) size polymorphism, an upstream pentanucleotide repeat (TTTTA(n)) affects Lp(a) levels. Several meta-analyses have provided support for an association between Lp(a) and coronary artery disease, and the levels of Lp(a) carried in particles with smaller size apo(a) isoforms are associated with cardiovascular disease or with preclinical vascular changes. Further, there is an interaction between Lp(a) and other risk factors for cardiovascular disease. The physiological role of Lp(a) is unknown, although a majority of studies implicate Lp(a) as a risk factor.

PKC-alpha mediated alterations of indoleamine contents in diabetic rat brain

We previously have reported that acute or chronic diabetes in animals resulted in altered neurotransmitter levels. In this study, we investigated the concentrations of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in discrete areas of brain viz. striatum (ST), hippocampus (HC), hypothalamus (HT), midbrain (MB), pons medulla (PM), cerebellum (CB) and cerebral cortex (CCX) of control, untreated diabetic and insulin treated diabetic rats after 30 days. Alloxan (45 mg/kg) diabetic untreated rats, which showed hyperglycemia (>250 mg%), revealed significant increases of 5-HT level in ST, MB, PM, CB and CCX and the 5-HIAA level found to be increased significantly in ST, HC and MB. Whereas the insulin treated rats, which was maintained under normal glucose level (80-110 mg%), showed no significant changes in any of the areas studied. The expressions of PKC-alpha studied by immunoblotting also showed significant changes in ST, HC, MB, PM, CB and CCX that is identical to the changes of both 5-HT and 5-HIAA under similar condition, suggesting that the PKC-alpha may regulate the synthesis and release of indoleamines in diabetic animals.

Utilisation of eye care services in rural south India: the Aravind Comprehensive Eye Survey

AIM

To determine utilisation of eye care services in a rural population of southern India aged 40 years or older.

METHODS

5150 subjects aged 40 years and older selected through a random cluster sampling technique from three districts in southern India underwent detailed ocular examinations for vision impairment, blindness, and ocular morbidity. Information regarding previous use of eye care services was collected from this population through a questionnaire administered by trained social workers before ocular examinations.

RESULTS

3476 (72.7%) of 5150 subjects examined required eye care examinations. 1827 (35.5%) people gave a history of previous eye examinations, primarily from a general hospital (n = 1073, 58.7%). Increasing age and education were associated with increased utilisation of eye care services. Among the 3323 people who had never sought eye care, 912 (27.4%) had felt the need to have an eye examination but did not do so. Only one third of individuals with vision impairment, cataracts, refractive errors, and glaucoma had previously utilised services.

CONCLUSIONS

A large proportion of people in a rural population of southern India who require eye care are currently not utilising existing eye care services. Improved strategies to improve uptake of services is required to reduce the huge burden of vision impairment in India.

Autonomic Modulation of the U Wave During Sympathomimetic Stimulation and Vagal Inhibition in Normal Individuals

Prolonged repolarization time, an important contributor to the pathogenesis of ventricular arrhythmias, is usually identified by a long QT interval (QT) on the ECG but is frequently confounded by the presence of a U wave. The physiological basis and clinical relevance of the U wave is unresolved. To better understand the relationship between the T and U waves, this study examined their behavior during nonresting autonomic conditions. Twenty-five healthy subjects were evaluated during sympathomimetic infusion with isoproterenol and vagal inhibition with atropine. As heart rate (HR) increased in response to isoproterenol, the QU interval (QU) decreased by an eightfold greater extent than QT. Furthermore, a marked increase in U wave amplitude and decrease in T wave amplitude were observed with T and U wave fusion at higher HRs. During atropine, QU decreased by only a threefold greater extent than QT, T and U wave amplitudes were affected only minimally, and T-U wave fusion was not observed. These results demonstrate that sympathomimetic stimulation causes striking alterations in the timing and amplitude of U waves that differ from effects on the T wave. These effects are not observed during vagal inhibition. Thus, the U wave represents a component of cardiac repolarization that is electrocardiographically and physiologically distinct from the T wave with a unique response to sympathomimetic stimulation.

Functional characterization of Na(+)/H(+) exchangers in primary cultures of prairie dog gallbladder

Gallbladder Na(+) absorption is linked to gallstone formation in prairie dogs. We previously reported Na(+)/H(+) exchanger (NHE1-3) expression in native gallbladder tissues. Here we report the functional characterization of NHE1, NHE2 and NHE3 in primary cultures of prairie dog gallbladder epithelial cells (GBECs). Immunohistochemical studies showed that GBECs grown to confluency are homogeneous epithelial cells of gastrointestinal origin. Electron microscopic analysis of GBECs demonstrated that the cells form polarized monolayers characterized by tight junctions and apical microvilli. GBECs grown on Snapwells exhibited polarity and developed transepithelial short-circuit current, I(sc), (11.6 +/- 0.5 microA. cm(-2)), potential differences, V(t) (2.1 +/- 0.2 mV), and resistance, R(t) (169 +/- 12 omega. cm(2)). NHE activity in GBECs assessed by measuring dimethylamiloride-inhibitable (22)Na(+) uptake under a H(+) gradient was the same whether grown on permeable Snapwells or plastic wells. The basal rate of (22)Na(+) uptake was 21.4 +/- 1.3 nmol x mg prot(-1) x min(-1), of which 9.5 +/- 0.7 (approximately 45%) was mediated through apically-restricted NHE. Selective inhibition with HOE-694 revealed that NHE1, NHE2 and NHE3 accounted for approximately 6%, approximately 66% and approximately 28% of GBECs' total NHE activity, respectively. GBECs exhibited saturable NHE kinetics ( V(max) 9.2 +/- 0.3 nmol x mg prot(-1) x min(-1); K(m) 11.4 +/- 1.4 m M Na(+)). Expression of NHE1, NHE2 and NHE3 mRNAs was confirmed by RT-PCR analysis. These results demonstrate that the primary cultures of GBECs exhibit Na(+) transport characteristics similar to native gallbladder tissues, suggesting that these cells can be used as a tool for studying the mechanisms of gallbladder ion transport both under physiologic conditions and during gallstone formation.

Overexpression of apoC-III produces lesser hypertriglyceridemia in apoB-48-only gene-targeted mice than in apoB-100-only mice

The adaptive value of apolipoprotein B-48 (apoB-48), the truncated form of apoB produced by the intestine, in lipid metabolism remains unclear. We crossed human apoC-III transgenic mice with mice expressing either apoB-48 only (apoB48/48) or apoB-100 only (apoB100/100). Cholesterol levels were higher in apoB48/48 mice than in apoB100/100 mice but triglyceride levels were similar. Lipid levels were increased by the apoC-III transgene. However, triglyceride levels were significantly higher in apoB100/100C-III than in apoB48/48C-III mice (895 +/- 395 mg/dl vs. 690 +/- 252 mg/dl; P <0.01), whereas cholesterol levels were higher in the apoB48/48C-III mice than in apoB100/100C-III (144 +/- 35 mg/dl vs. 94 +/- 30 mg/dl; P <0.00001). Triglyceride clearance from VLDL was impaired to a greater extent in apoB100/100C-III vs. apoB100/100 mice than in apoB48/48C-III vs. apoB48/48 mice. Triglyceride secretion rates were no different in apoC-III transgenic mice than in their nontransgenic littermates. ApoB-48 triglyceride-rich lipoproteins were more resistant to the triglyceride-increasing effects of apoC-III but appeared more sensitive to the remnant clearance inhibition. Our findings support a coordinated role for apoB-48 in facilitating the delivery of dietary triglycerides to the periphery. Consistent with such a mechanism, glucose levels were significantly higher in apoB48/48 mice vs. apoB100/100 mice, perhaps on the basis of metabolic competition.

Risk factors for age related cataract in a rural population of southern India: the Aravind Comprehensive Eye Study

AIM

To determine risk factors for lens opacities and age related cataract in an older rural population of southern India.

METHODS

A cross sectional population based study of 5150 people aged 40 years and above from 50 clusters from three districts in southern India. The lens was graded and classified after dilation using LOCS III system at the slit lamp for cataract. Definite cataract was defined as nuclear opalescence >/=3.0 and/or cortical cataract >/=3.0 and/or PSC >/=2.0.

RESULTS

Definite cataracts were found in 2449 (47.5%) of 5150 subjects and the prevalence of cataract increased with age. The age adjusted prevalence of cataract was significantly lower in males (p = 0.0002). Demographic risk factors-increasing age and illiteracy-were common for the three subtypes of cataract; females were more likely to have cortical cataracts and nuclear cataracts. Additionally, nuclear cataracts were associated with moderate smoking (OR:1.28, 95% CI:1.01 to 1.64), lean body mass indices (OR: 1.37, 95% CI: 1.17 to 1.59) and higher waist to hip ratios (OR: 0.67, 95% CI: 0.54 to 0.82); cortical cataracts with hypertension (OR: 1.39 95% CI:1.11 to 1.72), pseudoexfoliation (OR:1.53,95% CI:1.17 to 2.01), and moderate to heavy smoking; and posterior subcapsular cataracts with diabetes (OR:1.55, 95% CI:1.12 to 2.15), lean body mass (OR:1.32, 95% CI:1.11 to 1.57), and high waist to hip ratios (OR: 0.77, 95% CI: 0.62 to 0.94).

CONCLUSIONS

Risk factors for age related cataract in this population do not appear to be different from those reported in other populations. Further studies are required to identify the reason for the high prevalence of age related cataract and to understand better the role of each risk factor for cataractogenesis in this population.

Transplacental delivery of retinoid: the role of retinol-binding protein and lipoprotein retinyl ester

Retinoids are required for normal embryonic development. Both embryonic retinoid deficiency and excess result in congenital malformations. There is little understanding of the physiology underlying retinoid transfer from the maternal circulation to the embryo. We now report studies that explore this process using retinol-binding protein-deficient (RBP-/-) mice and mice that express human RBP on the RBP-/-) background. Our studies establish that dietary retinoid, bound to lipoproteins, can serve as an important source for meeting tissue retinoid requirements during embryogenesis. Indeed, retinyl ester concentrations in the circulations of pregnant RBP-/- mice are significantly elevated over those observed in wild-type mice, suggesting that lipoprotein retinyl esters may compensate for the absence of retinol-RBP during pregnancy. We also demonstrate, contrary to earlier proposals, that maternal RBP does not cross the placenta and cannot enter the fetal circulation. Overall, our data indicate that both retinol-RBP and retinyl esters bound to lipoproteins are able to provide sufficient retinoid to the embryo to allow for normal embryonic development.

Nocardia asteroides canaliculitis: a case report of uncommon aetiology

Ocular nocardiosis is an opportunistic infection and is believed to be a rare entity. We describe a rare case report of a patient with culture-positive Nocardia asteroides canaliculitis who presented with complaints of watering, purulent discharge and painful swelling of left lower eye lid. A purulent tenacious material was expressed from the punctum of lower eye lid and subjected to microbiological investigations such as smears and cultures. Smears and culture proved the presence of Nocardia asteroides in the sample collected from punctum.

Epidemiological characteristics and laboratory diagnosis of fungal keratitis. A three-year study

PURPOSE

To study the epidemiological characteristics and laboratory diagnosis of fungal keratitis seen at a tertiary eye care referral centre in South India.

METHODS

A retrospective review of all culture-proven fungal keratitis seen over a 3-year period, September 1999 through August 2002.

RESULTS

Fungal aetiology were confirmed in 1095 (34.4%) of 3183 corneal ulcers. The predominant fungal species isolated was Fusarium spp (471; 42.82%) followed by Aspergillus spp (286; 26%). Males (712; 65.08%) were more often affected (P<0.0001). A large proportion of the patients (732; 66.85%) were in the younger age group (21 to 50 years). A majority (879; 80.27%) came from rural areas (P<0.0001), and most patients (709; 64.75%) were farmers (P<0.0001). Ocular trauma (1009; 92.15%) was a highly significant risk factor (P<0.0001) and vegetative injuries (671; 61.28%) were identified as a significant cause for fungal keratitis (P<0.0001). 172 (15.71%) patients had concurrent diabetes mellitus. The sensitivity of 10% potassium hydroxide (KOH) wet mount preparation was higher (99.23%) than Gram-stained smear (88.73%) (P<0.0001). Incidence of fungal keratitis was higher between June and September.

CONCLUSION

Agricultural activity and related ocular trauma were principal causes of mycotic keratitis. A potassium hydroxide (KOH) wet mount preparation is a simple, and sensitive, method for diagnosis

Epidemiology of bacterial keratitis in a referral centre in south India

PURPOSE

To study the epidemiological characteristics of bacterial keratitis seen at a tertiary eye care referral centre in south India.

METHODS

A retrospective review of medical records of all culture-positive bacterial keratitis which were seen over a 3 years period, from September 1999 through August 2002 was performed. After clinical evaluation corneal scrapings were collected and subjected to culture and microscopy using standard protocols in all patients.

RESULTS

Out of 3183 corneal ulcers evaluated, 1043(32.77%) were found to be of bacterial aetiology. A total of 1109 bacterial pathogens were isolated from 1046 eyes with keratitis. The predominant bacterial species isolated was Streptococcus pneumoniae (37.5%). Males were 592(56.76%) and 451(43.24%) were females. There were 564(54.07%) rural residents and 479(45.93%) urban residents; this difference was statistically significant (p< 0.0001). Patients with age more than 50 years (60.2%) were affected significantly more than patients aged less than 50 years (30.8%). While 57.62% of patients were non-agricultural workers, 42.38% were farmers; this difference was statistically significant (p<0.0001). Co-existing ocular diseases predisposing to corneal ulceration were identified in 703(67.4%) patients, compared to other predisposing risk factors in 340(32.6%) patients. One hundred and seventy seven (16.97%) had corneal injury with soil and/or sand, compared to 115(11.03%) patients who had injury due to other materials and the difference was statistically significant. There was lower incidence of bacterial keratitis from June to September.

CONCLUSIONS

The epidemiological characteristics of bacterial keratitis vary geographically. This study describing the features of bacterial keratitis would greatly help the practising ophthalmologist and other medical practitioners in the management of their patients.

Blindness and vision impairment in a rural south Indian population: the Aravind Comprehensive Eye Survey

OBJECTIVE

To determine the prevalence of blindness and vision impairment in a rural population of southern India.

DESIGN

A population-based cross-sectional study.

PARTICIPANTS

A total of 17200 subjects aged 6 years or older, including 5150 subjects aged 40 years or older from 50 clusters representative of three southern districts of Tamil Nadu in southern India.

METHODS

All participants had preliminary screenings consisting of vision using a LogMAR illiterate E chart and anterior segment hand light examinations at the village level. Subjects aged 40 years or older were offered comprehensive eye examinations at the base hospital, including visual acuity using LogMAR illiterate E charts and refraction, slit-lamp biomicroscopy, gonioscopy, applanation tonometry, dilated fundus examinations, and automated Humphrey central 24-2 full threshold perimetry; subjects younger than 40 years of age who had any signs or symptoms of ocular disease were also offered comparable examinations at the base hospital.

MAIN OUTCOME MEASURES

Visual impairment was defined as best-corrected visual acuity <6/18, and blindness was defined using both Indian (<6/60) and World Health Organization (<3/60) definitions.

RESULTS

Comprehensive examinations at the base hospital were performed on 5150 (96.5%) of 5337 persons 40 years of age or older. Among those 40 years of age and older, presenting visual acuity at the <3/60 level was present in 4.3% (95% confidence interval [CI]: 3.8, 4.9) and 11.4% (95% CI: 10.6, 12.3) at the <6/60 level. After best correction, the corresponding figures were 1.0% (95% CI: 0.79, 1.2) and 2.1% (95% CI: 1.7, 2.5). Over 70% of subjects improved their vision by at least one line, and nearly a third by three lines after refraction. Age-related cataract was the most common potentially reversible blinding disorder (72.0%) among eyes presenting with blindness.

CONCLUSIONS

Blindness and vision impairment remain major public health problems in India that need to be addressed. Cataracts and refractive errors remain the major reversible causes for the burden of vision impairment in this rural population.