Biocompatible, smooth, plasma-treated nickel-titanium surface--an adequate platform for cell growth.

High nickel content is believed to reduce the number of biomedical applications of nickel-titanium alloy due to the reported toxicity of nickel. The reduction in nickel release and minimized exposure of the cell to nickel can optimize the biocompatibility of the alloy and increase its use in the application where its shape memory effects and pseudoelasticity are particularly useful, e.g., spinal implants. Many treatments have been tried to improve the biocompatibility of Ni-Ti, and results suggest that a native, smooth surface could provide sufficient tolerance, biologically. We hypothesized that the native surface of nickel-titanium supports cell differentiation and insures good biocompatibility. Three types of surface modifications were investigated: thermal oxidation, alkali treatment, and plasma sputtering, and compared with smooth, ground surface. Thermal oxidation caused a drop in surface nickel content, while negligible chemistry changes were observed for plasma-modified samples when compared with control ground samples. In contrast, alkali treatment caused significant increase in surface nickel concentration and accelerated nickel release. Nickel release was also accelerated in thermally oxidized samples at 600 °C, while in other samples it remained at low level. Both thermal oxidation and alkali treatment increased the roughness of the surface, but mean roughness R(a) was significantly greater for the alkali-treated ones. Ground and plasma-modified samples had 'smooth' surfaces with R(a)=4 nm. Deformability tests showed that the adhesion of the surface layers on samples oxidized at 600 °C and alkali treatment samples was not sufficient; the layer delaminated upon deformation. It was observed that the cell cytoskeletons on the samples with a high nickel content or release were less developed, suggesting some negative effects of nickel on cell growth. These effects were observed primarily during initial cell contact with the surface. The most favorable cell responses were observed for ground and plasma-sputtered surfaces. These studies indicated that smooth, plasma-modified surfaces provide sufficient properties for cells to grow.

Nonparametric predictive inference for exposure assessment.

Exposure assessment for food and drink consumption requires the combining of information about people's consumption of products with concentration data sets to provide predictions for chemical intake by humans. In this article, we present a method called nonparametric predictive inference (NPI) for exposure assessment. NPI is a distribution-free method relying only on Hill's assumption A(n). Effectively, A(n) is a postdata exchangeability assumption, which is a natural starting point for nonparametric statistics. For further discussion we refer to works by Hill and Coolen. We illustrate how NPI can be implemented to produce predictions for an individual's exposure based on consumption, body weight, and concentration data. NPI has the advantage that we do not have to assume a distribution to implement it. There may, however, be information available to suggest a distribution for a random quantity. Therefore, we present an NPI-Bayes hybrid method where this information can be taken into account by using Bayesian methods while using NPI for the other random quantities in the model.

Estimating the rate of poisoning by insecticide-treated seeds in a bird population.

Poisonings of granivorous birds by cereal seed treatments have been reported in the UK, but the true frequency of poisonings is unknown. We aimed to measure the rate of mortality due to poisoning by seed treatments in woodpigeons (Columba palumbus) in an area of East Anglian farmland where the risk from these compounds appeared high. Woodpigeons were fitted with temperature-sensing radio-tags and monitored daily during the winters of 1994/95 and 1995/96. Birds' deaths were detected and attempts made to retrieve carcasses for post-mortem examination including, where possible, analysis for pesticide residues. Ninety-one woodpigeons were monitored. Eleven birds died, but the causes of their deaths were uncertain: one contained a low residue of insecticide and in the other ten cases, no carcass was recovered, so no analysis was possible. Therefore, the number poisoned by pesticides could lie anywhere between zero and eleven. During 1994/95, estimated mortality ranged from 0% to 52%, depending on how many (if any) of the 11 casualties were poisoned. During 1995/96 there were no casualties. Using conservative diagnostic rules for classifying birds as poisoned by OP seed treatments, no link was found between the availability of treated fields in the study area and the rate of poisonings, and there were no significant differences between the two study years. For reasons discussed in the paper, true mortality resulting from exposure to insecticide seed treatments was considered likely to lie in the range 0-5%.

Case Study Part 2: Probabilistic modelling of long-term effects of pesticides on individual breeding success in birds and mammals.

Long term exposure of skylarks to a fictitious insecticide and of wood mice to a fictitious fungicide were modelled probabilistically in a Monte Carlo simulation. Within the same simulation the consequences of exposure to pesticides on reproductive success were modelled using the toxicity-exposure-linking rules developed by R.S. Bennet et al. (2005) and the interspecies extrapolation factors suggested by R. Luttik et al. (2005). We built models to reflect a range of scenarios and as a result were able to show how exposure to pesticide might alter the number of individuals engaged in any given phase of the breeding cycle at any given time and predict the numbers of new adults at the season's end.

Case Study Part 1: How to calculate appropriate deterministic long-term toxicity to exposure ratios (TERs) for birds and mammals.

In the European Union, first-tier assessment of the long-term risk to birds and mammals from pesticides is based on calculation of a deterministic long-term toxicity/exposure ratio (TER(lt)). The ratio is developed from generic herbivores and insectivores and applied to all species. This paper describes two case studies that implement proposed improvements to the way long-term risk is assessed. These refined methods require calculation of a TER for each of five identified phases of reproduction (phase-specific TERs) and use of adjusted No Observed Effect Levels (NOELs) to incorporate variation in species sensitivity to pesticides. They also involve progressive refinement of the exposure estimate so that it applies to particular species, rather than generic indicators, and relates spraying date to onset of reproduction. The effect of using these new methods on the assessment of risk is described. Each refinement did not necessarily alter the calculated TER value in a way that was either predictable or consistent across both case studies. However, use of adjusted NOELs always reduced TERs, and relating spraying date to onset of reproduction increased most phase-specific TERs. The case studies suggested that the current first-tier TER(lt )assessment may underestimate risk in some circumstances and that phase-specific assessments can help identify appropriate risk-reduction measures. The way in which deterministic phase-specific assessments can currently be implemented to enhance first-tier assessment is outlined.

A new interpretation of avian and Mammalian reproduction toxicity test data in ecological risk assessment.

The long-term risks of pesticides to wildlife in the EU currently are assessed by comparing the lowest no-observed-effect concentration (NOEC) determined from the suite of endpoints measured in existing avian and mammalian laboratory reproduction tests with estimated exposure concentrations by calculating Toxicity to Exposure Ratios (TERs). Regulatory authorities experience difficulties when assessing long-term risks because of the lack of accepted methods to improve the ecological realism of exposure and toxicity estimates and understand risks at a population level. This paper describes an approach for interpreting existing avian and mammalian toxicity test data that divides breeding cycles into several discrete phases and identifies specific test endpoints as indicators of direct pesticide effects possible at each phase. Based on the distribution of breeding initiation dates for a species of concern and the dates of pesticide applications, this approach compares the phase-specific toxicity endpoint with the expected pesticide exposure levels during each of the breeding phases. The fate of each breeding attempt is determined through a series of decision points. The cumulative reproductive response of individuals in a breeding population based on this decision framework provides a means of examining the estimated risks over the course of the breeding season and deriving an overall metric of the impact of the pesticide on reproduction. Research needed to further improve the approach is discussed.

Assessing potential exposure of birds to pesticide-treated seeds.

Seed treatments are widely used for crop protection and present a particular risk to granivorous birds. UK risk assessment for seed treatments has tended to focus on highly granivorous species; however, under some conditions, non-granivorous birds will take seeds. Better data is needed on which species eat seeds for which pesticide treatments are used. To identify which species will take and eat a range of crop seeds in common usage in the UK, birds visiting bait stations at which untreated seed was presented were video recorded. Information was also obtained on how much seed is taken by individual birds. The seeds tested were wheat, barley, maize, oilseed rape, grass, peas and pelleted sugar beet. For many of the species observed at the bait stations, the amounts of seed consumed during single visits were sufficient to pose a potential risk (toxicity-exposure ratio < 10) if the seed had been treated with one of the more acutely toxic seed treatments. Previous studies have shown that de-husking of seeds can substantially reduce birds' exposure. This paper provides information on which of the species recorded de-husked which seeds, in field conditions. The use of these data in pesticide risk assessment is considered.

Apolipoprotein E genotype and major depression in a community of older adults. The Cache County Study.

BACKGROUND: The role of allelic variation in APOE, the genetic locus for apolipoprotein E, in geriatric depression is poorly understood. There are conflicting reports as to an association between the epsilon4 allele and depression in late life. METHOD: Using a community based study of non-demented elders in Cache County, Utah, that included many very old individuals, we examined the relationship between APOE and late-onset (age > 60) depression, with particular attention to possible age effects. RESULTS: There was no overall association between APOE and depression. However, there was a significant interaction effect of APOE and age such that the relationship of late-onset depression with respect to presence of the epsilon4 allele was larger among those 80 and older compared with those below age 80. Consistent with previous studies, women were more likely to experience late-onset depression than men. CONCLUSIONS: Because we excluded prevalent cases of dementia, this pattern of relative risk with age may reflect the appearance of depressive symptoms as a prodrome of Alzheimer's disease or vascular dementia. Longitudinal studies should help to confirm or refute this explanation of the data.

Intake estimation of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in salmon: the inclusion of uncertainty.

Dioxins and dioxin-like PCBs are given toxic equivalency factors (TEFs) in order to calculate the combined toxic equivalence (TEQ) of these contaminants in a sample of food. This study calculates the probability of an average consumer exceeding the recommended tolerable daily intake of 1-4 pg WHO-TEQ kg(-1) bw day(-1) as the amount of salmon in the diet is increased. Probabilistic risk analysis is used to account for the known uncertainties in this calculation. When the TEF uncertainty was excluded with no salmon consumption, the background dietary intake ranged from 1.36 to 1.78 pg TEQ kg(-1) bw day(-1). A weekly consumption of three standard salmon portions resulted in a 36% chance of exceeding the upper limit of the TDI. Inclusion of the TEF uncertainty increased the background dietary intake range from 2.1 to 4.4 pg TEQ kg(-1) bw day(-1), and the weekly consumption of one salmon portion resulted in a 79% chance of the average consumer exceeding the upper TDI. The most important factors contributing to the uncertainty in these results were, in order of magnitude, the TEF for PCB 126 and the sampling uncertainty (sample size) followed by the measurement uncertainty of PCB 126. We recommend that it is more important to increase sample size and produce more precise estimates in the TEF than to improve analytical accuracy.

Effect of heat processing on in vitro protein digestibility and some chemical properties of African breadfruit (Treculia africana Decne) seeds.

The effects of dry heat (roasting) and moist heat (boiling) on in vitro protein digestibility, protein fractions and other chemical properties of African breadfruit (Treculia africana Decne) seed that affect their utilization as a source of human food were investigated. Chemical analyses showed that the crude protein and fat contents of the unprocessed (raw) seeds were 20. 1% and 13.7%, respectively. The level of phytic acid in the raw seed (1.19 mg/g) was lower than the levels found in some commonly consumed pulses in Nigeria. Albumin and globulin protein fractions were found to be the major seed proteins of African breadfruit seed, constituting 67.8% of the total protein of the raw seed. There were no significant (p > 0.05) differences between crude protein, ash and fat contents of the raw and heat processed samples. Boiling proved more effective than roasting for improving protein digestibility and for reducing the levels of trypsin inhibitor, phytic acid and polyphenols of the samples. The complete removal of these antinutrients, however, would require a more severe heat treatment of the seed, which in turn would profoundly reduce the nutritional value and availability of proteins, as demonstrated by the low values obtained for in vitro protein digestibility, protein fractions and protein extractability.

Prevalence of depression and its treatment in an elderly population: the Cache County study.

BACKGROUND: Previous estimates of the prevalence of geriatric depression have varied. There are few large population-based studies; most of these focused on individuals younger than 80 years. No US studies have been published since the advent of the newer antidepressant agents. METHODS: In 1995 through 1996, as part of a large population study, we examined the current and lifetime prevalence of depressive disorders in 4,559 nondemented individuals aged 65 to 100 years. This sample represented 90% of the elderly population of Cache County, Utah. Using a modified version of the Diagnostic Interview Schedule, we ascertained past and present DSM-IV major depression, dysthymia, and subclinical depressive disorders. Medication use was determined through a structured interview and a "medicine chest inventory." RESULTS: Point prevalence of major depression was estimated at 4.4% in women and 2.7% in men (P= .003). Other depressive syndromes were surprisingly uncommon (combined point prevalence, 1.6%). Among subjects with current major depression, 35.7% were taking an antidepressant (mostly selective serotonin reuptake inhibitors) and 27.4% a sedative/hypnotic. The current prevalence of major depression did not change appreciably with age. Estimated lifetime prevalence of major depression was 20.4% in women and 9.6% in men (P<.001), decreasing with age. CONCLUSIONS: These estimates for prevalence of major depression are higher than those reported previously in North American studies. Treatment with antidepressants was more common than reported previously, but was still lacking in most individuals with major depression. The prevalence of subsyndromal depressive symptoms was low, possibly because of unusual characteristics of the population.

Chemical composition of indigenous wild herbs, spices, fruits, nuts and leafy vegetables used as food.

Thirty wild fruits, nuts, herbs, spices and leafy vegetables were characterized and their chemical composition determined. Some of them were not only used for food, but for medicine in minor aliments by the natives. Results of the proximate analysis showed that on dry weight basis, the crude protein content ranged from 4.6 to 22.1 percent for spices and herbs, 3.2 to 43.1 percent for fruits and nuts, and 15.9 to 35.7 percent for leafy vegetables. The fat (ether extract) ranged from 7.5 to 36.0 percent for spices and herbs, 1.8 to 72.6 percent for fruits and nuts and 10.6 to 22.6 percent for leafy vegetables. Total carbohydrate content ranged from 34.6 to 71.9 percent for spices and herbs, 11.3 to 76.1 percent for fruits and nuts, and 24.6 to 51.4 percent for leafy vegetables. The wild fruits, nuts and leafy vegetables are high in ascorbic acid (Vitamin C.) Ascorbic acid content ranged from 18 mg/100 g dry sample to 113 mg/100 g sample for fruits and nuts, and 23 mg/100 g to 232 mg/100 g sample for leafy vegetables. The levels for peroxide value and free fatty acids (as percent oleic acid) of the spices are generally low indicating good storage stability of these plant materials. The flavour imparting essential oils (as percent oleoresin) content of the spices/herbs were fairly high and ranged from 0.1 to 5.2 percent.

Effect of processing and storage on the ascorbic acid (vitamin C) content of some pineapple varieties grown in the Rivers State of Nigeria.

Ascorbic acid contents of the juice of four different pineapples species grown in the Rivers State of Nigeria were determined before and after storage of whole pineapple and processing and storage of the juice for two months. Ascorbic acid of the fresh juice ranged from 22.5 mg to 33.5 mg/100 g sample. After storage at room temperature (30-32 degrees C) of whole pineapple for two weeks, ascorbic acid was reduced to between 59 and 65 percent of the fresh juice. Processing the juice by pasteurisation reduced the ascorbic acid to between 28 and 46 percent while storage in plastic bottles for two months further reduced the ascorbic acid content to between 10 and 21 percent.

The effect of methylxanthines on milk volume and composition, and growth of rat pups.

A study was conducted to investigate the effect of differential dose levels of methylxanthines on lactational performance, with respect to milk volume and composition and pup growth. The methylxanthines; caffeine, theophylline and theobromine, were administered via drinking water in the proportions occurring in tea, at a dose of 50, 1 and 2 mg/kg body-weight respectively to Wistar albino rats throughout pregnancy and for up to the 14th day of lactation. A fourth group received a mixture of all three methylxanthines. Maternal food and fluid intake and weight changes, as well as weight gain in the litter were monitored thrice weekly. Milk samples were collected from the dams on days 7 and 14 of lactation, while milk volume was measured on days 12-13 by a method using tritiated water. Results showed that caffeine and theobromine significantly enhanced litter weight (P less than 0.01 and 0.05 respectively). In the caffeine group, enhanced litter growth was due to a significant increase (P less than 0.05) in milk volume, consequent to increased maternal food intake (P less than 0.05). In the theobromine group there was only a weak association between increased litter weight and milk volume. Theophylline had no effect on the volume or composition of milk, or litter weight. The combination of all three methylxanthines also failed to produce any of the positive effects observed with separate drug treatments.