Vitamin D and health care costs: Results from two independent population-based cohort studies.

BACKGROUND & AIMS: Vitamin D deficiency is associated with higher morbidity. However, there is few data regarding the effect of vitamin D deficiency on health care costs. This study examined the cross-sectional and longitudinal associations between the serum 25-hydroxy vitamin D concentration (25OHD) and direct health care costs and hospitalization in two independent samples of the general population in North-Eastern Germany. METHODS: We studied 7217 healthy individuals from the 'Study of Health in Pomerania' (SHIP n = 3203) and the 'Study of Health in Pomerania-Trend' (SHIP-Trend n = 4014) who had valid 25OHD measurements and provided data on annual total costs, outpatient costs, hospital stays, and inpatient costs. The associations between 25OHD concentrations (modelled continuously using factional polynomials) and health care costs were examined using a generalized linear model with gamma distribution and a log link. Poisson regression models were used to estimate relative risks of hospitalization. RESULTS: In cross-sectional analysis of SHIP-Trend, non-linear associations between the 25OHD concentration and inpatient costs and hospitalization were detected: participants with 25OHD concentrations of 5, 10 and 15 ng/ml had 226.1%, 51.5% and 14.1%, respectively, higher inpatient costs than those with 25OHD concentrations of 20 ng/ml (overall p-value = 0.001) in multivariable models. CONCLUSIONS: We found a relation between lower 25OHD concentrations and increased inpatient health care costs and hospitalization. Our results thus indicate an influence of vitamin D deficiency on health care costs in the general population.

Attitudes and perceptions of health care workers in Northeastern Germany about multidrug-resistant organisms.

There were 256 health care workers in 39 facilities who were interviewed about their perceptions of the quality of care of patients with and without multidrug-resistant organisms based on a standardized questionnaire. There are remarkable differences in the responses between facility types (acute care hospitals, long-term care hospitals, rehabilitation hospitals, and home care services). Hygiene management must be specifically tailored to the requirements of each facility.

Different pathways of molecular pathophysiology underlie cognitive and motor tauopathy phenotypes in transgenic models for Alzheimer's disease and frontotemporal lobar degeneration.

A poorly understood feature of the tauopathies is their very different clinical presentations. The frontotemporal lobar degeneration (FTLD) spectrum is dominated by motor and emotional/psychiatric abnormalities, whereas cognitive and memory deficits are prominent in the early stages of Alzheimer's disease (AD). We report two novel mouse models overexpressing different human tau protein constructs. One is a full-length tau carrying a double mutation [P301S/G335D; line 66 (L66)] and the second is a truncated 3-repeat tau fragment which constitutes the bulk of the PHF core in AD corresponding to residues 296-390 fused with a signal sequence targeting it to the endoplasmic reticulum membrane (line 1; L1). L66 has abundant tau pathology widely distributed throughout the brain, with particularly high counts of affected neurons in hippocampus and entorhinal cortex. The pathology is neuroanatomically static and declines with age. Behaviourally, the model is devoid of a higher cognitive phenotype but presents with sensorimotor impairments and motor learning phenotypes. L1 displays a much weaker histopathological phenotype, but shows evidence of neuroanatomical spread and amplification with age that resembles the Braak staging of AD. Behaviourally, the model has minimal motor deficits but shows severe cognitive impairments affecting particularly the rodent equivalent of episodic memory which progresses with advancing age. In both models, tau aggregation can be dissociated from abnormal phosphorylation. The two models make possible the demonstration of two distinct but nevertheless convergent pathways of tau molecular pathogenesis. L1 appears to be useful for modelling the cognitive impairment of AD, whereas L66 appears to be more useful for modelling the motor features of the FTLD spectrum. Differences in clinical presentation of AD-like and FTLD syndromes are therefore likely to be inherent to the respective underlying tauopathy, and are not dependent on presence or absence of concomitant APP pathology.

Prospective association of low serum total testosterone levels with health care utilization and costs in a population-based cohort of men.

Despite the burgeoning interest in the field of andrology, no studies have specifically addressed the impact of serum testosterone levels on healthcare utilization and costs. We analysed data from the population-based cohort Study of Health in Pomerania (SHIP), Germany, to assess the association of serum testosterone levels with self-reported health care utilization and costs at baseline and at 5 years follow up. Study sample comprised 2023 men at baseline, of whom 1530 men were repeatedly examined. Low and high serum testosterone levels, defined according to the age-specific 10th and 90th percentile, were compared with reference subjects with serum testosterone levels ≥10th -≤90th percentile. Two-part econometric models were applied adjusting for socio-economic and medical confounders. Cross-sectional models revealed higher numbers of outpatient visits and higher costs for both, men with low (+19.1 and +19.9%, respectively) and high serum testosterone levels (+25.3 and +30.2%, respectively), whereas number of inpatient days and costs were not associated with serum testosterone levels. Adjustment for age, educational level, income, waist circumference, smoking status, physical activity and alcohol consumption did not considerably alter the results. Longitudinal models revealed a significant association of low serum testosterone levels with increased number of follow-up outpatient visits (age-adjusted: +28.6%) and costs (+38.0%) only. Low and high serum testosterone levels were associated with increased short-term outpatient health care costs, whereas low serum testosterone levels appear to be predictive of long-term outpatient health care costs. Cost-effectiveness studies of available treatments are necessary to identify benefits for physicians, patients and health care system as a whole.

Socio-economic impact of antiviral intervention.

In this paper we present a meta-analysis of the Cost-of-Illness of HIV/AIDS and the socio-economic impact of antiretroviral therapy. We distinguish between provider costs, direct household costs, and indirect costs. There is a growing number of publications on provider costs in different countries, but the methodology and the degree of precision between these papers make it difficult to give a good estimate of the current provider costs of treating HIV/AIDS cases. There seems to be a declining interest in health economic analysis of HIV/AIDS, and usually data is rather obsolete at the date of publication. In addition, we know hardly anything about household costs not covered by health insurances (e.g., transport to the provider, special diet). There are more studies on indirect costs, but even these studies are difficult to compare due to methodological differences. Even under these conditions we can state that in highly developed countries HAART is cost-effective. Because of an increase of life expectancy, the life-time provider costs increase under this drug regime. But, on the contrary, the indirect costs strongly decrease. In particular for employed and young HIV/AIDS cases in the USA and in Europe, HAART is an investment that pays back. In countries and in compartments of the population (e.g., unemployed, pensioners) where the loss of labor can be neglected, the positive effects of HAART on the indirect costs do not necessarily justify its costs. The cost-effectiveness analysis of antiviral therapy has to be seen under the precondition that no long-term effects, such as drug resistance, occur. Future analysis might show that we strongly underestimated the long-term costs of HIV/AIDS.

Full-genome RNAi profiling of early embryogenesis in Caenorhabditis elegans.

A key challenge of functional genomics today is to generate well-annotated data sets that can be interpreted across different platforms and technologies. Large-scale functional genomics data often fail to connect to standard experimental approaches of gene characterization in individual laboratories. Furthermore, a lack of universal annotation standards for phenotypic data sets makes it difficult to compare different screening approaches. Here we address this problem in a screen designed to identify all genes required for the first two rounds of cell division in the Caenorhabditis elegans embryo. We used RNA-mediated interference to target 98% of all genes predicted in the C. elegans genome in combination with differential interference contrast time-lapse microscopy. Through systematic annotation of the resulting movies, we developed a phenotypic profiling system, which shows high correlation with cellular processes and biochemical pathways, thus enabling us to predict new functions for previously uncharacterized genes.

Transfer of YACs up to 2.3 Mb intact into human cells with polyethylenimine.

The transfer of large YAC DNA into human cells is a laborious procedure. High quality pulsed field gel purified DNA is required, which is easily sheared during manipulation before transfection or degraded in the endosome of the cell following transfection. NaCl and polyamines compact and prevent DNA from shearing, but may not consistently protect DNA after transfection. We investigated if other polycations such as poly-L-lysine (PLL) and polyethylenimine (PEI) could condense and protect large YAC DNA (up to 2.3 Mb) from being degraded after lipofection. DNA condensation was monitored by a gel retardation assay, and atomic force microscopy (AFM). DNA was retarded in the gel when complexed with high concentrations of PLL and PEI, indicating that DNA had condensed. However, AFM images of PLL-DNA complexes showed aggregates of DNA molecules resulting from incomplete condensation, whereas PEI-DNA complexes produced condensed particles approximately 30-60 nm. Exogenous PLL-DNA remained intact in 36% of positive clones after lipofection, whereas PEI-DNA was intact in 100% of positive clones. PEI is a better condensing reagent than PLL, protecting DNA from shearing and endosomal degradation, and assists in delivering YACs up to 2.3 Mb intact into human cells.

Inhibition of luciferase expression by synthetic hammerhead ribozymes and their cellular uptake.

Two synthetic hammerhead ribozymes, one unmodified and the other with 2"-modifications and four phosphorothioate groups, targeting a single GUA site in the luciferase mRNA, were compared for their inhibition of gene expression in cell cultureand their cellular uptake was also analysed. A HeLa X1/5 cell line stably expressing luciferase, under an inducible promoter, was treated with these ribozymes by liposome-mediated transfection to determine their activity. Luciferase expression in cells was inhibited to approximately 50% with little difference between the unmodified and the 2"-modified ribozyme. A similar degree of inhibition was observed with two catalytically inactive ribozymes, indicating that inhibition was mainly due to an antisense effect. A ribozyme carrying a cholesterol moiety, applied to the cells without carrier, showed no inhibition. Northern blotting indicated a similar amount of cellular uptake of all ribozymes. The unmodified ribozyme was essentially evenly distributed between cytoplasm and nucleus, whereas a higher proportion of the phosphorothioate-containing ribozyme was observed in the nucleus. Fluorescence microscopy, including confocal microscopy using 5"-fluorescein-labelled ribozymes, showed that the unmodified and 2"-modified ribozymes were present in the cytoplasm and in the nucleus to a similar extent, whereas the fluorescence of the phosphorothioate-containing ribozyme was much stronger in the nucleus. Both ribozymes inhibited luciferase expression to a comparable degree, suggesting that the ribozyme in the nucleus did not contribute significantly to the inhibition. Ribozymes with a cholesterol moiety were predominantly trapped in the cell membrane, explaining their inability to interfere with gene expression.

The subcellular localization and length of hammerhead ribozymes determine efficacy in human cells.

The length requirements of the antisense portion of hammerhead ribozymes for efficacy in living cells was investigated. The HIV-1tat-directed asymmetric hammerhead ribozyme alphaYRz195 was used with a 195 nt 3'-antisense arm and a 3 nt 5'-antisense portion as well as a set of successively 3'-shortened derivatives thereof. In the 3'-antisense arm a minimum length of 20 complementary nucleotides was required for efficient association with a 645 nt target RNA transcript in vitro(for all constructs kass ranged between 0.3 and 1.8x104/M/s). The cleavage rate constants (kcleav) were independent of the length of the antisense flank and ranged between 0.8 and 1.2x10-4/s. However, the length of the antisense arms, as well as the mode of delivery and the subcellular location of the ribozymes, had a dramatic effect on efficacy in HIV-1-producing human cells. When proviral HIV-1 DNA and ribozymes were co-microinjected into the nucleus of human cells, a minimum length of 51 nt in the antisense arm was necessary for antisense- and ribozyme-mediated inhibition of HIV-1 replication. Ribozymes with shorter antisense arms were almost ineffective. Conversely, short chain ribozymes, including those with chemical modifications, were superior to long chain ribozymes when co-microinjected into the cytoplasm. When transfected, all ribozymes showed an antisense effect as well as an additional ribozyme-mediated increase in inhibition. Consequences for the design and application of ribozymes are discussed.

Inhibition of gene expression with ribozymes.

1. Ribozymes can be designed to cleave in trans, i.e. several substrate molecules can be turned over by one molecule of the catalytic RNA. Only small molecular weight ribozymes, or small ribozymes, are discussed in this review with particular emphasis on the hammerhead ribozyme as this has been most widely used for the inhibition of gene expression by cleavage of mRNAs. 2. Cellular delivery of the ribozyme is of crucial importance for the success of inhibition of gene expression by this methodology. Two modes of delivery can be envisaged, endogenous and exogenous delivery. Of the former several variants exist, depending on the vector used. The latter is still in its infancy, even though chemical modification has rendered such ribozymes resistant against degradation by serum nucleases without impairment of catalytic efficiency. 3. Various successful applications of ribozymes for the inhibition of gene expression are discussed, with particular emphasis on HIV1 and cancer targets. These examples demonstrate the promise of this methodology.

Self-report and stability of physical symptoms by adolescents.

Verbal reports of physical complaints and their relationship to school-related stress was investigated in two adolescent samples. It was hypothesized that symptom reporting is a function of age and sex, and is connected to psychological factors such as test (state) and trait anxiety. In addition, the consistency of symptoms reported during the course of one year was evaluated. It was found that, overall, the two adolescent groups complained of more physical symptoms than did Brähler's (1978) adult sample. Differences between males and females in reporting symptoms were apparent only in the older adolescent group (ages 14 to 15); females reported more physical complaints. The positive correlation between body symptoms and test-trait anxiety was highly significant. During the year, few adolescents exhibited well-defined patterns of body complaints. On the contrary, many complaints seemed to be transient phenomena, although the number was high. In this respect, adolescence plays an important role in the self-reporting evaluation and development of physical complaints.