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Zinc is an essential trace element in human nutrition and its deficiency is a world nutritional problem. However, the zinc content of foods is low and its availability is conditioned by several physiologic and dietary factors. For that reason, the objective of the present work is to compile past and present information about the influence of these factors on zinc availability to try to improve this availability.
The objective of this study was to quantify the importance of societal aging relative to other factors that are known to affect injury risk. An aging population's effect on Maximum Abbreviated Injury Scale (MAIS) 3+ injury trends for passenger car drivers in frontal crashes was projected and compared to the effects of projected changes in fleet composition, changes in seat belt usage, and changes in air bag availability. It was determined that increased frailty due to an aging population will result in 19,816 to 43,568 additional injuries to passenger car drivers in frontal crashes from 1996 to 2012. Aging was shown to have an effect similar to the increased presence of light trucks in the fleet (a cumulative increase of approximately 47,428 injuries). Aging and changing fleet composition were shown to have a smaller effect than the projected increases in seat belt use or air bag availability, though the effect of increased belt use is not much greater than the effect of aging. After 2012, however, air bag availability and seat belt use will plateau, while societal aging will continue.
The relationship between human sex ratios at birth and caloric availability per capita was examined across different countries. Significant positive correlations were obtained between the amount of food a country had available and the percentage of male births. Furthermore, increases or decreases in a country's caloric availability were related to corresponding changes in that country's sex ratio. These results provide evidence of adaptive sex ratio biasing in humans. The physiological mechanism by which this effect operates is probably higher mortality rates for male embryos and fetuses as a result of nutritional deficiencies and associated stressors.
This study has been conducted to determine whether the rheological differences depending on gelling and treatment conditions could have an influence on drug availability. Lipogels with constant composition were obtained by gelling olive oil with monodiglycerides at rest, under stirring, and milled after gelling. The considerable differences in rheological characteristics produced significant differences on in vitro drug release tests, whereas a lesser influence was observed on in vitro simulated absorption test. The rheological differences appeared not to influence in vivo drug availability. Also, rheological differences owing to the concentration of the gelling agent showed no significant influence on in vivo availability.
Since an influenza virus variant of pandemic potential may appear at any time, plans must be made to use currently available vaccines and antivirals most advantageously. Inactivated vaccines remain the principal intervention for the near future, and it can be assumed that quantities available at critical points in the epidemic will be limited unless advances are made in methods of vaccine production. Repeated demonstration of the effectiveness of vaccination of older persons in preventing hospitalization and death confirms that the traditional high-risk groups should be given priority. Since community transmission can be interrupted by vaccinating school-age children, this group may also be targeted. Antivirals in use and under development will almost certainly be active against the pandemic variant. Use during pandemics should be extensive but may be limited by the quantity of drugs available, the logistics of storage and distribution, and the possibility of side effects.
Numerous instruments are commercially available to measure heart rate variability, yet little is known regarding the agreement between such instruments. The objective of this study is to assess agreement between measures of heart rate variability in three commercially available instruments. Thirty subjects (20 males) of median age 27.5 (range 19-59 years) underwent simultaneous ECG recordings, under three different resting conditions: supine, standing and supine with controlled breathing, using three commercially available analysers. Intraclass correlation coefficients tended to show excellent agreement (lower 95% C.I., R > 0.75) between all instruments under all conditions. However, further analysis of selected measurements using the limits of agreement method revealed large variation in values generated by all instruments. There was also an evidence of systematic bias between one instrument and the remaining two. The latter finding was due to discrepant ECG recording protocols that were unrelated to consistent operator timing. This study demonstrates that measures of HRV generated by the three instruments did not agree well in all cases. Discrepancies were due to the recording protocols of the systems. This may lead to incomparable results between instruments. It is therefore recommended that: (a) if different instruments are used in the same study or (b) multi-centre study designs are planned or (c) heart rate variability results are discussed with reference to studies using other instruments, levels of agreement need to be reported to ensure comparability.
OBJECTIVES: to evaluate the effectiveness of a policy of making hip protectors available to residents of nursing homes. DESIGN: a cluster randomised controlled trial of the policy in nursing and residential homes, with the home as the unit of randomisation. SETTING: 127 nursing and residential homes in the greater Belfast area of Northern Ireland. PARTICIPANTS: 40 homes in the intervention group (representing 1,366 occupied beds) and 87 homes in the control group (representing 2,751 occupied beds). INTERVENTIONS: a policy of making hip protectors available free of charge to residents of nursing homes and supporting the implementation process by employing a nurse facilitator to encourage staff in the homes to promote their use, over a 72-week period. MAIN OUTCOME MEASURES: the rate of hip fractures in intervention and control homes, and the level of adherence to use of hip protectors. RESULTS: there were 85 hip fractures in the intervention homes and 163 in the control homes. The mean fracture rate per 100 residents was 6.22 in the intervention homes and 5.92 in the control homes, giving an adjusted rate ratio for the intervention group compared to the control group of 1.05 (95% CI 0.77, 1.43, P = 0.76). Initial acceptance of the hip protectors was 37.2% (508/1,366) with adherence falling to 19.9% (272/1,366) at 72 weeks. CONCLUSIONS: making hip protectors available to residents of nursing and residential homes did not reduce the rate of hip fracture. This research does not support the introduction of a policy of providing hip protectors to residents of nursing homes.
In population-based surveys, sample lists are often out of date by the time data collection begins. Consequently, response rates, and the perceived validity of the survey, may be compromised by the unknowing inclusion of ineligible subjects. A strategy to address this issue is ascertainment of survey nonrespondents' eligibility status, enabling post hoc adjustment of response rates. In 1995-1996, population surveys were carried out in two Ontario, Canada, communities. Despite intensive follow-up, the status of 8949 (18.6%) of the 48218 potential subjects in these surveys remained unknown. In response, 500 "unknowns" from each community were randomly selected for tracing by using publicly available telephone directories and, where applicable, city directories. These tracing efforts classified persons into one of three groups: "ineligible" (moved before the mailing), "true nonresponder" (present when the survey was mailed), and "remains unknown" (no directory listing found). Publicly available directories clarified the status of 76.0% of potential participants, reducing the proportion of "unknowns" from 18.6% to 4.6%. Applying the estimated proportions of "ineligibles" from each area resulted in response rates adjusted from 63.8% to 71.2% and from 72.8% to 74.9% in the survey areas. Publicly available directories were used to successfully trace the majority of survey nonresponders, thus strengthening confidence in the survey's results.
PURPOSE: A hospital-based program simulating nonprescription access to emergency contraception (EC) is described. METHODS: A collaborative agreement between the pharmacy and therapeutics committee and the pharmacy department was initiated at a safety-net teaching hospital to provide EC to clinic patients directly from the hospital pharmacy without the need to first see a health care provider. EC was available 24 hours per day to any woman requesting it at the hospital pharmacy, with the collaborative agreement serving as the prescription. During clinic hours, patients were directed to the outpatient pharmacy to request EC. After hours, patients went to the emergency department triage desk and were directed to the inpatient pharmacy. Patients making inquiries about EC were encouraged to see their health care provider as soon as possible for counseling about contraceptive options. No specific program was initiated for publicizing the increased availability of EC, as it was assumed that health care providers and word-of-mouth would inform patients of this option. RESULTS: The program was initiated in the fourth quarter of 2001. Total doses of EC dispensed increased nearly eightfold over the 1.5-year study period since the inception of this program. Most of this increase (81%) was attributable to the collaborative agreement. Twenty-eight percent of EC was dispensed outside of regular clinic hours. No patient complaints regarding this plan were received, and pharmacy staff did not believe that this program presented a significant additional burden to their workload. CONCLUSION: A collaborative agreement simulating nonprescription availability increased the use of EC in a hospital-based clinic setting.
UNLABELLED: Certain types of genetic analysis are simplified by assembling a collection of unrelated individuals, e.g. case-control experiments. If a family study is being performed then it will be necessary to extract subsets of unrelated, available individuals from pedigress. Our program provides an optimal method for performing this task. AVAILABILITY: The software is available, free of charge, on request from Oxagen Ltd. SUPPLEMENTARY INFORMATION: http://www.oxagen.co.uk
The basal ganglia play a role in controlling movement during gait. The aim of the present study was to investigate changes in dopamine transporter (DAT) availability in the striatum and extrastriatal region in association with walking exercise in six normal subjects and seven age-matched unmedicated patients with Parkinson's disease. This was done by comparing DAT radioligand uptake in the dopaminergic projection areas after gait with that under the resting condition using a DAT probe, 11C-labelled 2-beta-carbomethoxy-3beta-(4-fluorophenyl) tropane ([11C]CFT) and PET. Physiological parameters were stable during and after gait in both groups. The regions of interest method for measuring differences in [11C]CFT uptake level and voxel-based statistical parametric mapping (SPM96) showed that [11C]CFT uptake in the striatum (specifically the putamen) was decreased by gait to a greater extent in normal subjects, whereas a significant reduction in [11C]CFT uptake was not found in the putamen but in the caudate and orbitofrontal cortex in Parkinson's disease patients. These results are the first in vivo evidence that DAT availability is reduced in the nigrostriatal projection area by basic human behaviour, i.e. gait. Alterations in this availability in Parkinson's disease suggested that shifted activation in the medial striatum and the mesocortical dopaminergic system might reflect the pathophysiology of parkinsonian gait.
A method for the quantitative determination of the total available lysine in various foods is developed. The method is based on the reaction of the amino groups on the lysine molecule with fluorodinitrobenzene and is capable of furnishing simultaneous determination of the available intrachain lysine (known as N-epsilon-[2,4-dinitrophenyl]-L-lysine) or the available free and/or N-terminal lysine (known as N,N'-di-[2,4-dinitrophenyl]-L-lysine). Optimum conditions for separation and quantitation are studied. The results show the proposed method to be both accurate and precise and suitable for food samples containing hydrolyzed proteins.
The availability of new biotechnologies has led to the prediction that new or improved vaccines can be developed for 27 diseases within the next decade. The reasons why such optimism cannot be extended to the availability of vaccines for many other infectious diseases are considered by reviewing the steps in vaccine development, from identification of the etiologic agent to construction of attenuated or inactivated vaccines. Impediments to development may exist or arise at any point in this pathway (e.g., multiplicity of serotypes, inability to cultivate the pathogen, multistage life cycles with multiple antigens, unpredictability of epidemics, inadequate knowledge of pathogenesis and immunity, fear of gene splicing, need for an adjuvant, and lack of profitability). Diseases for which vaccines are not likely to be available in the next decade include trachoma, onchocerciasis, pneumonia due to Legionella and to mycoplasmas, amebiasis and giardiasis, schistosomiasis, syphilis, chlamydial urethritis, trypanosomiasis, leishmaniasis, and filariasis, and non-A, non-B hepatitis.
Volatile anesthetics affect all cells and tissues tested, but their mechanisms and sites of action remain unknown. To gain insight into the cellular activities of anesthetics, we have isolated genes that, when overexpressed, render Saccharomyces cerevisiae resistant to the volatile anesthetic isoflurane. One of these genes, WAK3/TAT1, encodes a permease that transports amino acids including leucine and tryptophan, for which our wild-type strain is auxotrophic. This suggests that availability of amino acids may play a key role in anesthetic response. Multiple lines of evidence support this proposal: (i) Deletion or overexpression of permeases that transport leucine and/or tryptophan alters anesthetic response; (ii) prototrophic strains are anesthetic resistant; (iii) altered concentrations of leucine and tryptophan in the medium affect anesthetic response; and (iv) uptake of leucine and tryptophan is inhibited during anesthetic exposure. Not all amino acids are critical for this response since we find that overexpression of the lysine permease does not affect anesthetic sensitivity. These findings are consistent with models in which anesthetics have a physiologically important effect on availability of specific amino acids by altering function of their permeases. In addition, we show that there is a relationship between nutrient availability and ubiquitin metabolism in this response.
Older adults consistently report having fewer close and fewer problematic social ties than do younger adults. Yet, prior studies have not explicitly examined associations between the availability of living relatives and the nature of family ties in later life. One hundred sixty-four individuals ages 13 to 99 described their networks of close and problematic social ties. Then they provided information about specific living relatives (e.g., spouse, mother, father, sons, daughters, siblings, grandparents, and grandchildren). Older individuals reported more living relatives than did adolescents or young adults. Although individuals of all ages tended to name the majority of living relatives as close social contacts, most adults did not name all available relatives as close contacts. Age differences emerged with regard to naming relatives as problematic social ties. Older adults were less likely to indicate that their relatives caused problems. Findings are discussed in terms of an extension of investment theory, the availability hypothesis, which suggests that individuals with few living relatives are likely to view more of these relatives as close ties and fewer of these relatives as problematic.
Dictyostelium discoideum has been suggested as a eukaryotic model organism for glycobiology studies. Presently, the characteristics of acceptor sites for the N-acetylglucosaminyl-transferases in Dictyostelium discoideum, which link GlcNAc in an alpha linkage to hydroxyl residues, are largely unknown. This motivates the development of a species specific method for prediction of O-linked GlcNAc glycosylation sites in secreted and membrane proteins of D. discoideum. The method presented here employs a jury of artificial neural networks. These networks were trained to recognize the sequence context and protein surface accessibility in 39 experimentally determined O-alpha-GlcNAc sites found in D. discoideum glycoproteins expressed in vivo. Cross-validation of the data revealed a correlation in which 97% of the glycosylated and nonglycosylated sites were correctly identified. Based on the currently limited data set, an abundant periodicity of two (positions-3, -1, +1, +3, etc.) in Proline residues alternating with hydroxyl amino acids was observed upstream and downstream of the acceptor site. This was a consequence of the spacing of the glycosylated residues themselves which were peculiarly found to be situated only at even positions with respect to each other, indicating that these may be located within beta-strands. The method has been used for a rapid and ranked scan of the fraction of the Dictyostelium proteome available in public databases, remarkably 25-30% of which were predicted glycosylated. The scan revealed acceptor sites in several proteins known experimentally to be O-glycosylated at unmapped sites. The available proteome was classified into functional and cellular compartments to study any preferential patterns of glycosylation. A sequence based prediction server for GlcNAc O-glycosylations in D. discoideum proteins has been made available through the WWW at http://www.cbs.dtu.dk/services/DictyOGlyc/ and via E-mail to DictyOGlyc@cbs.dtu.dk.
Microsurgical epididymal sperm aspiration (MESA) combined with intracytoplasmic sperm injection (ICSI) represents a great advance in the therapy of non-reconstructable obstructive azoospermia. For procedure synchronization, a great number of organizational facilities are needed. Intentional cryopreservation of the aspirate may reduce these problems, therefore the aim of this study was to analyse the amount and quality of aspirate fluid obtained by means of MESA and the quality of the vials after thawing. Furthermore, the available cryopreserved straws were calculated. A total of 93 consecutive MESA procedures were performed and epididymal spermatozoa were obtained in 88 patients. Mean sperm concentration was 40.9 x 10(6) spermatozoa/ml. Global and progressive motility were 24.8 and 7.5% respectively. In one-third of the aspirates, no progressive motile spermatozoa were found. The mean number of straws available was 7.6. In 33 ICSI cycles with frozen-thawed epididymal spermatozoa, a pregnancy rate of 42.4% was achieved. In conclusion, these data show that enough spermatozoa are available for various ICSI cycles following a single MESA procedure in men with non-reconstructable obstructive azoospermia. Furthermore, ICSI with cryopreserved spermatozoa leads to excellent pregnancy rates
In higher plants, inorganic nitrogen has crucial effects on growth and development, providing cellular components and modulating gene expression. To date, not only nitrogen assimilatory genes but also a substantial number of genes with other functions have been shown to be selectively regulated by the availability of nitrogen. In terms of the communicating substance(s) between root and shoot, accumulating evidence suggests that nitrate itself is the primary signal molecule triggering the activation of transcription of nitrate assimilation and related genes. On the other hand, some of the genes involved in photosynthesis, cell cycling and translation machinery are also regulated, at least in part, by nitrate and other nitrogen sources and, in some cases, the effect can be mimicked by cytokinin treatment. Spatial and temporal studies on the accumulation levels and the translocation of cytokinin in response to nitrate replenishment in maize showed subsequent accumulation of various cytokinin species in the roots, xylem sap and leaves. In Arabidopsis thaliana, trans-zeatin riboside-5'-monophosphate and/or trans-zeatin riboside also accumulated in the roots in response to nitrate resupply. These studies suggest that cytokinin metabolism and translocation could be commonly modulated by nitrogen availability in higher plants. Thus, in addition to nitrate, cytokinin could be another root-to-shoot signal communicating nitrogen availability.