Determinants of intraocular pressure and its association with glaucomatous optic neuropathy in Chinese Singaporeans: the Tanjong Pagar Study

PURPOSE: To examine the relationship between intraocular pressure (IOP), anthropomorphic, demographic, socioeconomic, systemic, and ocular factors and glaucomatous optic neuropathy (GON) in Chinese people. METHODS: Chinese people (n = 2000), aged 40 to 79 years, were selected from the Singapore electoral register. Of the 1717 considered eligible for examination, 1232 participated, representing a response rate of 71.8%. IOP was estimated with Goldmann applanation tonometry. The drainage angle was assessed with static and dynamic gonioscopy. The optic nerve was examined at high magnification through a dilated pupil with a fundus contact lens or a +78-D lens. Static automated visual field testing was performed on subjects with suspected glaucoma. GON was diagnosed on the basis of structural and functional abnormalities of the optic nerve. RESULTS: The main independent determinants of higher IOP were higher systolic blood pressure (P < 0.001), quadrants of any peripheral anterior synechiae (PAS, P = 0.02) and width of the drainage angle (P = 0.049). A 100- micro m increase in corneal thickness was associated with an increase in mean IOP of 1.5 to 1.8 mm Hg (P < 0.001). Odds of GON increased 1.2 times per 1-mm Hg increase in screening IOP. A clear association between corneal thickness and GON was not identified. CONCLUSIONS: Clinical IOP estimates are related to systolic blood pressure and corneal thickness. Variation in IOP with angle width may suggest that trabecular compaction significantly contributes to causes of the increase in IOP, independent of angle-closure. GON is an IOP-related phenomenon among Chinese Singaporeans.     

Equation for corneal asphericity after corneal refractive surgery

PURPOSE: To determine the exact theoretical asphericity after refractive surgery when the parabolic approximation of the Munnerlyn formula is utilized. METHOD: From a least-square analysis and considering the conicoid model for anterior cornea, we calculated the final asphericity (p'-factor) from the preoperative asphericity and the radii before and after surgery. RESULTS: The final p'-factor is given by p'=p(R'3/R3); R' is the final radius of curvature; R is the preoperative radius; and p is the preoperative p'-factor. CONCLUSIONS: This equation for postoperative asphericity may be useful in studying the influence on asphericity of different surgical variables. It allows comparisons of real asphericity with the asphericity that should theoretically result. It also explains the increased spherical aberration after refractive surgery and the deterioration of retinal image quality that some authors have found experimentally.     

A Bayesian method for predicting 5-fluorouracil pharmacokinetic parameters following short-term infusion in patients with colorectal cancer

The objective of this study was to develop a population pharmacokinetic model and validate it using a Bayesian approach for predicting, a priori and a posteriori, the individual volume of distribution (V(d)) and clearance (Cl) of 5-fluorouracil (5-FU) given as short-term intravenous infusion in weekly and multiple doses. Forty-four patients were divided in group A (5-FU weekly doses) including 27 patients with nonmetastatic colorectal adenocarcinoma treated with 450 mg/m(2) of 5-FU, 1 day per week for 48 doses, plus oral levamisol (50 mg/8 h) for 3 days, every 15 days and group B (5-FU multiple doses) including 17 patients with metastatic colorectal adenocarcinoma, receiving 5-FU (425 mg/m(2)) plus intravenous folinic acid (20 mg/m(2)) over 5 consecutive days, every 4 weeks for six cycles. In both groups 5-FU was administered as a 30-60-min infusion. A total of 176 plasma concentrations were analyzed using a NONMEM program according to a linear one-compartment model. In group A, 5-FU population pharmacokinetic parameters were obtained and the covariables studied were age, gender, weight, ideal body weight, height, body surface area, creatinine clearance, and hepatic function tests. A priori and a posteriori validation of this model was carried out with plasma concentrations obtained in day 1 in group B. In group B, population pharmacokinetic parameters of 5-FU following multiple doses were estimated using scale factors to identify differences in 5-FU V(d) and Cl between days 1 and 4, and the interindividual, interoccasion, and residual variabilities studied. V(d) was 0.266 L/kg of ideal body weight and Cl was 1.21 L/h. kg of total weight following weekly doses. The plasma sample obtained at 10 min gave the best accuracy and precision predictions. When 5-FU was administered in multiple doses, the Cl of the drug in day 4 is reduced by 30.14% compared to day 1. The interoccasion variability was lower than interindividual variability for both V(d) and Cl, suggesting that it could be feasible to individualise dosage of 5-FU for subsequent cycles from data obtained in a previous one in an attempt to improve the therapeutic index of colorectal cancer treatment.     

The selective iGluR1-4 (AMPA) antagonist LY300168 attenuates morphine-withdrawal-induced activation of locus coeruleus neurons and behavioural signs of morphine withdrawal

Previously, we have shown that the AMPA (iGluR1-4) antagonist LY293558 attenuates the morphine-withdrawal-induced activation of locus coeruleus neurons and behavioral signs of morphine withdrawal. However, LY293558 has since been shown to also have affinity for one subtype of kainate receptor (iGluR5). In this study, we examined the effects of a selective antagonist of iGluR1-4 receptors, LY300168 (GYKI 53655), and a selective antagonist of iGluR5 receptors, LY382884, on the morphine-withdrawal-induced activation of locus coeruleus neurons and behavioral signs of morphine withdrawal. In in vivo recordings from anesthetized rats, pretreatment with LY300168 (0.3-3.0 mg/kg, s.c.), but not LY382884 (at a dose known to have central effects; 100 mg/kg, s.c.) attenuated the morphine-withdrawal-induced activation of LC neurons. In unanesthetized, morphine-dependent rats, pretreatment with LY300168 (0.3-3.0 mg/kg, s.c.), but not LY382884 (100 mg/kg, s.c.), suppressed the severity and occurrence of naltrexone-precipitated morphine-withdrawal signs. These results indicate iGluR1-4 (AMPA) receptors, but not iGluR5 receptors, play an important role the morphine-withdrawal-induced activation of LC neurons and a subset of behavioral signs of morphine withdrawal. In addition, selective AMPA antagonists may have therapeutic effects in man for the treatment of withdrawal from opiates and other drugs of abuse.     

Toxic potential of oleander derived compost and vegetables grown with oleander soil amendments

California recycles 50% of previously disposed trash. Increased use of yardwastes and composts has raised concern about toxic materials in these products. Oleander is a toxic shrub common to CA landscapes and is frequently clipped and disposed of in greenwaste containers, resulting in concerns about the toxicity of oleander-contaminated yardwastes and composts from these wastes. Information about breakdown of oleandrin (one of the glycoside toxicants of oleander) during composting or the ability of plants to absorb this molecule has not been reported. In separate experiments, we documented the apparent first-order disappearance of oleandrin from composts of pure oleander, with a disappearance half-life of 15 d. Within 50 d, 90% of the oleandrin was removed during aerobic composting in a turned pile. In an amendment study with fresh uncomposted oleander, no oleandrin was detected in tomato and zuchinni fruit, snap beans, carrot tubers, or green lettuce. Oleandrin was found in red leaf lettuce growing in soils mulched with oleander, but oleandrin concentrations were near the detection limit of the assay. Soil from oleander mulched and amended plots contained low levels of oleandrin at the time of harvest.     

n-3 Fatty acids plus oleic acid and vitamin supplemented milk consumption reduces total and LDL cholesterol,homocysteine and levels of endothelial adhesion molecules in healthy humans

BACKGROUND AND AIMS: Numerous studies suggest n -3 polyunsaturated fatty acids (n -3 PUFA) and oleic acid intake have beneficial effects on health including risk reduction of coronary heart disease. The purpose of this study was to evaluate the effect of a commercially available skimmed milk supplemented with n -3 PUFA, oleic acid, and vitamins E, B(6), and folic acid (Puleva Omega3) on risk factors for cardiovascular disease. (CVD). METHODS: Thirty volunteers were given 500 ml/day of semi-skimmed milk for 4 weeks and then 500 ml/day of the n -3 enriched milk for 8 further weeks. Plasma and LDL lipoproteins were obtained from volunteers at the beginning of the study (T(pre)), and at 4, 8 and 12 weeks. RESULTS: The consumption of n -3 enriched milk produced a significant decrease in plasma concentration of total and LDL cholesterol accompanied by a reduction in plasma levels of homocysteine. Plasma and LDL oxidability and vitamin E concentration remained unchanged throughout the study. A significant reduction in plasma levels of vascular cell adhesion molecule 1, and an increase in plasma concentration of folic acid were also observed. CONCLUSION: Daily intake of n -3 PUFA and oleic acid supplemented skimmed milk plus folic acid and B-type vitamins has favourable effects on risk factors for CVD.     

Influenza coverages in Spain and vaccination-related factors in the subgroup aged 50-64 years

This study sought to describe influenza vaccination coverages for different Spanish population subgroups, stressing the analysis of vaccination-related factors in subjects aged 50-64 years and estimating the possible beneficial effect of extending universal vaccination to this age group. A total of 6,400 surveys, targeting subjects over the age of 16 years and drawn from the 1997 Spanish National Health Survey, were used for study purposes. Influenza coverage was observed to rise significantly with age, and the reason cited by most subjects for seeking vaccination was medical indication. Coverage of the 50-64 age group was 21.6% (95% CI 19.4-23.8) and the variables associated with a greater probability of being vaccination were: residence in towns or cities with <10,000 inhabitants (OR 1.45); monthly income of less than 600 (OR 1.71); and presence of associated chronic disease (OR 3.07.) It is estimated that in Spain, 524,514 (40.7%) persons aged 50-64 years with associated chronic disease receive and 764,218 persons aged 50-64 years with associated chronic disease do not receive influenza vaccine. We conclude that the extremely high number of subjects in the 50-64 age range susceptible to influenza-related complications each year constitutes good grounds for universal vaccination being extended to said age group.     

Challenges and perspectives of veterinary public health

This article presents the conceptual basis for veterinary public health-VPH, including historical aspects of its constitution and development, its fields of action, and its current challenges. It also presents a reflection on VPH within the frame of the veterinary services and it finally proposes that education plays a fundamental role in order to face the challenges of a new era.