Do cardiovascular risk factors explain the relation between socioeconomic status, risk of all-cause mortality, cardiovascular mortality, and acute myocardial infarction?

Much remains to be understood about how low socioeconomic status (SES) increases cardiovascular disease and mortality risk. Data from the Kuopio Ischemic Heart Disease Risk Factor Study (1984-1993) were used to estimate the associations between acute myocardial infarction and income, all-cause mortality, and cardiovascular mortality in a population-based sample of 2,272 Finnish men, with adjustment for 23 biologic, behavioral, psychologic, and social risk factors. Compared with the highest income quintile, those in the bottom quintile had age-adjusted relative hazards of 3.14 (95% confidence interval (CI) 1.77-5.56), 2.66 (95% CI 1.25-5.66), and 4.34 (95% CI 1.95-9.66) for all-cause mortality, cardiovascular mortality, and AMI, respectively. After adjustment for risk factors, the relative hazards for the same comparisons were 1.32 (95% CI 0.70-2.49), 0.70 (95% CI 0.29-1.69), and 2.83 (95% CI 1.14-7.00). In the lowest income quintile, adjustment for risk factors reduced the excess relative risk of all-cause mortality by 85%, that of cardiovascular mortality by 118%, and that of acute myocardial infarction by 45%. These data show how the association between SES and cardiovascular mortality and all-cause mortality is mediated by known risk factor pathways, but full "explanations" for these associations will need to encompass why these biologic, behavioral, psychologic, and social risk factors are differentially distributed by SES.     

HLA-DRB1 genes and disease severity in rheumatoid arthritis. The MIRA Trial Group. Minocycline in Rheumatoid Arthritis

OBJECTIVE: To examine the effect of alleles encoding the "shared"/"rheumatoid" epitope on rheumatoid arthritis (RA) disease severity in patients who participated in the minocycline in RA (MIRA) trial. METHODS: Of 205 patients with a week-48 visit, blood was available for typing of HLA-DRB1 and HLA-DQB1 in 174 (85%) and successfully completed in 169 (82%). Baseline erosions were used to assess disease severity and new erosions at the last visit served as a proxy for progression. RESULTS: At baseline, there was no association between the presence of erosive disease or rheumatoid factor status and the dose of rheumatoid epitope (homozygous, heterozygous, none) or the specific alleles identified. At the final visit, a gradient was observed for the 3 allelic subgroups (and their gene doses) in the occurrence of new erosions among the Caucasian placebo-treated, but not the minocycline-treated, patients. A treatment group/HLA-DR4 epitope interaction was demonstrated in multivariate analyses. Approximately two-thirds of African-American patients did not have the rheumatoid epitope. CONCLUSION: HLA-DRB1 oligotyping may be useful in predicting the progression of disease in some Caucasian patients. Our study corroborates the infrequency of the epitope among African-American patients with RA.     

Hypoxic ventilatory responsiveness in Tibetan compared with Han residents of 3,658 m

Lifelong high-altitude residents of North and South America acquire blunted hypoxic ventilatory responses and exhibit decreased ventilation compared with acclimatized newcomers. The ventilatory characteristics of Himalayan high-altitude residents are of interest in the light of their reportedly lower hemoglobin levels and legendary exercise performance. Until recently, Sherpas have been the only Himalayan population available for study. To determine whether Tibetans exhibited levels of ventilation and hypoxic ventilatory drives that were as great as acclimatized newcomers, we compared 27 lifelong Tibetan residents of Lhasa, Tibet, China (3,658 m) with 30 acclimatized Han ("Chinese") newcomers matched for age, body size, and extent of exercise training. During room air breathing, minute ventilation was greater in the Tibetan than in the Han young men because of an increased respiratory frequency, but arterial O2 saturation and end-tidal PCO2 did not differ, indicating similar levels of effective alveolar ventilation. The Tibetan subjects had higher hypoxic ventilatory response shape parameter A values and hypercapnic ventilatory responsiveness than the Han subjects. Among the Han subjects, duration of high-altitude residence correlated with the degree of blunting of the hypoxic ventilatory drive. Paradoxically, hyperoxia (inspired O2 fraction 0.70) increased minute ventilation and decreased end-tidal PCO2 in the Tibetan but not in the Han men. We concluded that lifelong Tibetan residents of high altitude neither hypoventilated nor exhibited blunted hypoxic ventilatory responses compared with acclimatized Han newcomers, suggesting that the effects of lifelong high-altitude residence on ventilation and ventilatory response to hypoxia differ in Tibetan compared with other high-altitude populations.     

Failure of triiodothyronine to inhibit TSH-mediated thyroid hormone release in man

We studied the effect of short-term triiodothyronine administration on thyroid gland responsivity to exogenous thyrotropin in four euthyroid human subjects. Thyroidal iodine release and serum thyroxine during daily im injections of bovine TSH were not significantly inhibited, despite a four-fold elevation in serum T3 concentrations. This negative finding contrasts with earlier positive reports of a regulatory "short-loop" effect of elevated circulating T3 on the thyroid gland. This difference may be due either to the use in previous murine or in vitro studies of non-physiologic, high doses of exogenous T3, or failure to control the withdrawal of the trophic effect of endogenous TSH in man on the subsequent glandular response.     

Optical activity and conformation of cobra neurotoxin

Cobra neurotoxin from Formosan cobra (Naja naja atra) venom is a compact globular protein having an intrinsic viscosity of 4.5 mL/g. The protein is stable in 7.5 M urea but can be denatured in 4.1 M guanidine hydrochloride or at elevated temperature (above 70 degrees C). Its conformation remains virtually the same in solvents of lower polarity than water such as 1,2-ethanediol or a mixed solvent of 1-propanol-1,2-ethanediol-water (5:1:1 by volume). The circular dichroism spectrum is "atypical" in water in that the peptide chromophores show a small negative circular dichroic (CD) band at 215 nm, a large positive one at 199 nm, and another large negative one below 190 nm. The CD pattern resembles to some extent that of a beta form but differs in both positions and magnitudes from the latter. It agrees qualitatively with the theoretical calculations of the reverse beta bends, suggesting that cobra toxin contains a considerable amount of beta turns and possibly a mixture of beta form and beta turns.     

Ultrastructure of ischemic contracture of the left ventricle ("stone heart")

Myocardial biopsies from two patients who had developed "stone heart" (myocardial rigor mortis; ischemic contracture of the left ventricle) were studied by electron microscopy. The ultrastructure of tissue in stone heart, though ischemic in nature, differed from that of classic myocardial infarction in some respects. Apart from depletion of glycogen and distension of the sarcoplasmic reticulum and T-tubules, myofibrillar degeneration was much more widespread. Mitochondrial degeneration with active lysosomal autodigestion, disruption of the microcirculation, and lymphedema were prominent changes also observed. In the light of known clinical and experimental observations, our findings suggest that stone heart is an accelerated form of ischemic injury occurring in vulnerable (hypertrophied) hearts and is probably related to ischemia-triggered release of endogenous catecholamines.     

Primary beneficiation of tantalite using magnetic separation and acid leaching

Primary beneficiation was successfully performed prior to dissolution of manganotantalite （sample A） and ferrotantalite （sample C） samples obtained from two different mines in the Naquissupa area, Mozambique. Magnetic separation removed the majority of iron and titanium, whereas H2SO4 leaching removed a large portion of thorium and uranium in these samples. Analytical results indicated that 64.14wt% and 72.04wt% of the total Fe and Ti, respectively, and -2wt% each of Nb205 and Ta205 were removed from sample C （ferrotantalite） using the magnetic separation method, whereas only 9.64wt% and 8.66wt% of total Fe203 and TiO2, respectively, and -2wt% each of NbEOs and Ta2O5 were removed from sample A （manganotantalite）. A temperature of 50℃ and a leaching time of 3 h in the presence of concentrated HESOa were observed to be the most appropriate leaching conditions for removal of radioactive elements from the tantalite ores. The results obtained for sample A under these conditions indicated that 64.14wt% U3O8 and 60.77wt% ThO2 were leached into the acidic solution, along with 4.45wt% and 0.99wt% of Nb2O5 and Ta2O5, respectively.     

Measures of larval lake whitefish length and abundance as early predictors of year-class strength in Lake Michigan

Many lake whitefish stocks in Lake Michigan have experienced substantial declines in growth and condition since the 1990s. Reduced growth and condition could result in reduced quality or quantity of eggs produced by spawning females, which in turn could negatively impact recruitment. We evaluated the potential for reduced recruitment by measuring early life stage density and length, and we discuss the utility of these measures as early indicators of lake whitefish year-class strength. Overall, mean larval density (number per 1000 m³ ± SE) in Lake Michigan was greater in 2006 (373.7 ± 28.3) than in 2005 (16.6 ± 24.8); whereas, mean length (mm ± SE) of larval lake whitefish was smaller in 2006 (12.87 ± 0.07) than in 2005 (14.38 ± 0.13). The ratio of zooplankton to fish density did not show an expected relationship with larval fish density or length. Rather, variation in larval density was best explained by a multiple-regression model that included larval length, spring wind intensity, and adult stock density as predictor variables. Our results suggest that the density of larval lake whitefish is not directly regulated by temperature or zooplankton density at the time of emergence, but that a potential for density-dependent regulation exists when larval emergence rates are high. We conclude that the observed declines in growth and condition of adult lake whitefish are not resulting in substantial reductions in recruitment.     

Studies of the copolymerisation of acrylic acid with n‐butyl vinyl ether

BACKGROUND: Copolymers of acrylic acid (AA) are important materials for the preparation of glass ionomer cements. Copolymerisation of AA is widely used to alter the acid strength of the material and to increase the number of salt bridges formed in cements. In this paper we report the copolymerisation of AA with n‐butyl vinyl ether (BVE) to form unique copolymers of the hemiacetal ester and with BVE incorporated into the main chain. RESULTS: AA and BVE undergo a spontaneous reaction to form a hemiacetal ester which can itself undergo free radical copolymerisation. The kinetics of this reaction in the bulk state have been examined. In addition, under these conditions BVE is incorporated into the polymer main chain via a free radical mechanism. CONCLUSION: Novel copolymers of the hemiacetal ester and BVE have been prepared in this study. The hemiacetal side chains are labile under moderate heating, being converted back to the acid analogue. Copyright © 2009 Society of Chemical Industry     

Determinant spreading associated with demyelination in a nonhuman primate model of multiple sclerosis

Definition of the immune process that causes demyelination in multiple sclerosis is essential to determine the feasibility of Ag-directed immunotherapy. Using the nonhuman primate, Callithrix jacchus jacchus (common marmoset), we show that immunization with myelin basic protein and proteolipid protein determinants results in clinical disease with significant demyelination. Demyelination was associated with spreading to myelin oligodendrocyte glycoprotein (MOG) determinants that generated anti-MOG serum Abs and Ig deposition in central nervous system white matter lesions. These data associate intermolecular "determinant spreading" with clinical autoimmune disease in primates and raise important issues for the pathogenesis and treatment of multiple sclerosis.