Prevalence Rates of Diabetic Retinopathy and Undiagnosed Diabetes Among Delaware Nursing Home and Assisted Living Facility Residents.

Objectives: To determine the prevalence of diabetic retinopathy and undiagnosed diabetes among Delaware nursing home and assisted care facility residents. Methods: This cross-sectional study involved the statistical analysis of comprehensive eye examination records of 2,063 nursing home residents residing in 18 facilities and 4 assisted living facilities in Delaware from 2005 to 2009. Descriptive statistical analyses were conducted to identify the rates of retinal dot and blot hemorrhages and existing systemic diabetes diagnoses. Results: The mean age of nursing home and assisted care facility residents was 77 years (range 9-104), and 64.4% were over the age of 80. Most residents were female (61.1%) and white (72.5%). 3.6% of the 2,063 nursing home residents had blot or dot hemorrhages in one or both eyes. 32.8% had a type 1 or type 2 diabetes diagnosis. Of the ones with a positive dot and blot hemorrhage finding, 56.8% had a diagnosis of diabetes, and 43.2% did not. Discussion: There was a high prevalence of dot and blot hemorrhages without a systemic diagnosis of diabetes, indicating a need for regular eye care among residents.

Vision Loss Among Delaware Nursing Home Residents.

Objectives: To determine the prevalence of vision loss among Delaware nursing home residents for further data collection to expand the existing evidence about the vision loss among nursing home residents on a national level. Methods: This cross-sectional study involved the statistical analysis of comprehensive eye examination records of 1,856 nursing residents residing in 20 Delaware nursing homes from 2005 to 2011. Descriptive statistical analyses were conducted to identify age-specific prevalence rates of vision loss (moderate-to-severe vision impairment and blindness). Results: The mean age of nursing home residents was 82.54 years (range: 65-111 years), and 61.70% were over the age of 80 years. The majority of nursing home residents were female (64.10%) and White (76.30%). The overall prevalence rates of moderate-to-severe vision impairment and blindness were 47.40% and 16.20%, respectively. Discussion: The high prevalence of vision loss among Delaware Nursing home residents indicates a demand for further data collection for expanding the existing evidence about the vision loss among nursing home residents on a national level.

Dose-Response-Time Data Analysis: An Underexploited Trinity.

The most common approach to in vivo pharmacokinetic and pharmacodynamic analyses involves sequential analysis of the plasma concentration- and response-time data, such that the plasma kinetic model provides an independent function, driving the dynamics. However, in situations when plasma sampling may jeopardize the effect measurements or is scarce, nonexistent, or unlinked to the effect (e.g., in intensive care units, pediatric or frail elderly populations, or drug discovery), focusing on the response-time course alone may be an adequate alternative for pharmacodynamic analyses. Response-time data inherently contain useful information about the turnover characteristics of response (target turnover rate, half-life of response), as well as the drug's biophase kinetics (biophase availability, absorption half-life, and disposition half-life) pharmacodynamic properties (potency, efficacy). The use of pharmacodynamic time-response data circumvents the need for a direct assay method for the drug and has the additional advantage of being applicable to cases of local drug administration close to its intended targets in the immediate vicinity of target, or when target precedes systemic plasma concentrations. This review exemplifies the potential of biophase functions in pharmacodynamic analyses in both preclinical and clinical studies, with the purpose of characterizing response data and optimizing subsequent study protocols. This article illustrates crucial determinants to the success of modeling dose-response-time (DRT) data, such as the dose selection, repeated dosing, and different input rates and routes. Finally, a literature search was also performed to gauge how frequently this technique has been applied in preclinical and clinical studies. This review highlights situations in which DRT should be carefully scrutinized and discusses future perspectives of the field.

Challenging the dose-response-time data approach: Analysis of a complex system.

This study presents an extensive dose-response-time (DRT) meta-analysis of the nicotinic acid-induced inhibition of free fatty acids and insulin release. The purpose was to quantify the implications of lacking exposure data when analysing complex pharmacodynamic systems. The DRT model successfully characterised various response behaviours-including time-delays, rebound, feedback mechanisms, and adaptation-on both the individual and the population level. Comparing the fitted DRT model to an exposure-driven reference analysis showed that bias and uncertainty were introduced in the parameter estimates. However, most estimates were within one standard error from the reference. In both approaches, a few parameters suffered from practical identifiability issues, likely due to large differences in half-lives of the different rate processes. Moreover, the optimal dosing strategies predicted by the DRT model differed slightly from those of the exposure-driven analysis, having a lower optimal steady-state reduction of free fatty acids exposure.

Modeling of free fatty acid dynamics: insulin and nicotinic acid resistance under acute and chronic treatments.

Nicotinic acid (NiAc) is a potent inhibitor of adipose tissue lipolysis. Acute administration results in a rapid reduction of plasma free fatty acid (FFA) concentrations. Sustained NiAc exposure is associated with tolerance development (drug resistance) and complete adaptation (FFA returning to pretreatment levels). We conducted a meta-analysis on a rich pre-clinical data set of the NiAc-FFA interaction to establish the acute and chronic exposure-response relations from a macro perspective. The data were analyzed using a nonlinear mixed-effects framework. We also developed a new turnover model that describes the adaptation seen in plasma FFA concentrations in lean Sprague-Dawley and obese Zucker rats following acute and chronic NiAc exposure. The adaptive mechanisms within the system were described using integral control systems and dynamic efficacies in the traditional [Formula: see text] model. Insulin was incorporated in parallel with NiAc as the main endogenous co-variate of FFA dynamics. The model captured profound insulin resistance and complete drug resistance in obese rats. The efficacy of NiAc as an inhibitor of FFA release went from 1 to approximately 0 during sustained exposure in obese rats. The potency of NiAc as an inhibitor of insulin and of FFA release was estimated to be 0.338 and 0.436 [Formula: see text], respectively, in obese rats. A range of dosing regimens was analyzed and predictions made for optimizing NiAc delivery to minimize FFA exposure. Given the exposure levels of the experiments, the importance of washout periods in-between NiAc infusions was illustrated. The washout periods should be [Formula: see text]2 h longer than the infusions in order to optimize 24 h lowering of FFA in rats. However, the predicted concentration-response relationships suggests that higher AUC reductions might be attained at lower NiAc exposures.

Dose-response-time modelling: Second-generation turnover model with integral feedback control.

This study presents a dose-response-time (DRT) analysis based on a large preclinical biomarker dataset on the interaction between nicotinic acid (NiAc) and free fatty acids (FFA). Data were collected from studies that examined different rates, routes, and modes of NiAc provocations on the FFA time course. All information regarding the exposure to NiAc was excluded in order to demonstrate the utility of a DRT model. Special emphasis was placed on the selection process of the biophase model. An inhibitory Imax-model, driven by the biophase amount, acted on the turnover rate of FFA. A second generation NiAc/FFA model, which encompasses integral (slow buildup of tolerance - an extension of the previously used NiAc/FFA turnover models) and moderator (rapid and oscillatory) feedback control, was simultaneously fitted to all time courses in normal rats. The integral feedback control managed to capture an observed 90% adaptation (i.e., almost a full return to baseline) when 10 days constant-rate infusion protocols of NiAc were used. The half-life of the adaptation process had a 90% prediction interval between 3.5-12 in the present population. The pharmacodynamic parameter estimates were highly consistent when compared to an exposure-driven analysis, partly validating the DRT modelling approach and suggesting the potential of DRT analysis in areas where exposure data are not attainable. Finally, new numerical algorithms, which rely on sensitivity equations to robustly and efficiently compute the gradients in the parameter optimization, were successfully used for the mixed-effects approach in the parameter estimation.

On-line gas chromatographic analysis of higher alcohol synthesis products from syngas.

An on-line gas chromatographic (GC) system has been developed for rapid and accurate product analysis in catalytic conversion of syngas (a mixture of H2 and CO) to alcohols, so called "higher alcohol synthesis (HAS)". Conversion of syngas to higher alcohols is an interesting second step in the route of converting coal, natural gas and possibly biomass to liquid alcohol fuel and chemicals. The presented GC system and method are developed for analysis of the products formed from syngas using alkali promoted MoS2 catalysts, however it is not limited to these types of catalysts. During higher alcohol synthesis not only the wanted short alcohols (∼C2-C5) are produced, but also a great number of other products in smaller or greater amounts, they are mainly short hydrocarbons (olefins, paraffins, branched, non-branched), aldehydes, esters and ketones as well as CO2, H2O. Trace amounts of sulfur-containing compounds can also be found in the product effluent when sulfur-containing catalysts are used and/or sulfur-containing syngas is feed. In the presented GC system, most of them can be separated and analyzed within 60 min without the use of cryogenic cooling. Previously, product analysis in "higher alcohol synthesis" has in most cases been carried out partly on-line and partly off-line, where the light gases (gases at room temp) are analyzed on-line and liquid products (liquid at room temp) are collected in a trap for later analysis off-line. This method suffers from many drawbacks compared to a complete on-line GC system. In this paper an on-line system using an Agilent 7890 gas chromatograph equipped with two flame ionization detectors (FID) and a thermal conductivity detector (TCD), together with an Agilent 6890 with sulfur chemiluminescence dual plasma detector (SCD) is presented. A two-dimensional GC system with Deans switch (heart-cut) and two capillary columns (HP-FFAP and HP-Al2O3) was used for analysis of the organic products on the FIDs. Light inorganic gases (H2, CO, CO2, N2) and methane were separated on packed columns and quantified with the TCD. The "sulfur GC" was optimized for on-line trace level sulfur analysis in hydrocarbon matrices and used to understand to which degree sulfur is released from the catalyst and incorporated into the liquid product, and if so in which form. The method provides excellent quantitative measurements with a carbon material balance near 99.5% (carbon in/carbon out) for individual measurement points.

Preclinical manufacture of an anti-HER2 scFv-PEG-DSPE, liposome-inserting conjugate. 1. Gram-scale production and purification.

A GMP-compliant process is described for producing F5cys-PEG-lipid conjugate. This material fuses with preformed, drug-loaded liposomes, to form "immunoliposomes" that bind to HER2/neu overexpressing carcinomas, stimulates drug internalization, and ideally improves the encapsulated drug's therapeutic index. The soluble, single-chain, variable region antibody fragment, designated F5cys, was produced in E. coli strain RV308 using high-density cultures. Affinity adsorption onto horizontally tumbled Streamline rProtein-A resin robustly recovered F5cys from high-pressure-disrupted, whole-cell homogenates. Two product-related impurity classes were identified: F5cys with mid-sequence discontinuities and F5cys with remnants of a pelB leader peptide. Low-pressure cation exchange chromatography, conducted at elevated pH under reducing conditions, enriched target F5cys relative to these impurities and prepared a C-terminal cysteine for conjugation. Site-directed conjugation, conducted at pH 5.9 +/- 0.1 with reaction monitoring and cysteine quenching, yielded F5cys-MP-PEG(2000)-DSPE. Low-pressure size exclusion chromatography separated spontaneously formed, high-molecular-weight conjugate micelles from low-molecular-weight impurities. When formulated at 1-2 mg/mL in 10 mM trisodium citrate, 10% sucrose (w/v), at pH 6.4 (HCl), the conjugate was stable when stored below -70 degrees C. Six scale-up lots were compared. The largest 40-L culture produced enough F5cys to manufacture 2,085 mg of conjugate, enough to support planned preclinical and future clinical trials. The conjugate was 93% pure, as measured by polyacrylamide gel electrophoresis. Impurities were primarily identified as product-related. Residual endotoxin, rProtein A, and genomic DNA, were at acceptable levels. This study successfully addressed a necessary step in the scale-up of immunoliposome-encapsulated therapeutics.

Potato gene Y-1 is an N gene homolog that confers cell death upon infection with potato virus Y.

ADG2 is a DNA sequence mapped to a resistance (R) gene-rich region at the distal end of chromosome XI in potato (Solanum tuberosum subsp. andigena). The gene, in which ADG2 represents the predicted nucleotide-binding domain (NBS), was cloned and characterized. The coding region of the gene (designated as Y-1) is 6,187 bp long and structurally similar to gene N that confers hypersensitive resistance to Tobacco mosaic virus in Nicotiana spp. Both belong to the TIR-NBS-LRR class of genes and show 57% identity at the amino acid sequence level. The introns of Y-1 were spliced as predicted from the sequence. Y-1 cosegregated with Ry(adg), a gene for extreme resistance to Potato virus Y (PVY) on chromosome XI, as tested in a potato-mapping population and with independent potato cultivars. Leaves of the transgenic potato plants expressing Y-1 under the control of Cauliflower mosaic virus 35S promoter developed necrotic lesions upon infection with PVY, but no significant resistance was observed, and plants were systemically infected with PVY.

Role of RpoS in virulence and stress tolerance of the plant pathogen Erwinia carotovora subsp. carotovora.

The plant-pathogenic bacterium Erwinia carotovora subsp. carotovora causes plant disease mainly through a number of extracellular plant-cell-wall-degrading enzymes. In this study, the ability of an rpoS mutant of the Er. carotovora subsp. carotovora strain SCC3193 to infect plants and withstand environmental stress was characterized. This mutant was found to be sensitive to osmotic and oxidative stresses in vitro and to be deficient in glycogen accumulation. The production of extracellular enzymes in vitro was similar in the mutant and in the wild-type strains. However, the rpoS mutant caused more severe symptoms than the wild-type strain on tobacco plants and also produced more extracellular enzymes in planta, but did not grow to higher cell density in planta compared to the wild-type strain. When tested on plants with reduced catalase activities, which show higher levels of reactive oxygen species, the rpoS mutant was found to cause lower symptom levels and to have impaired growth. In addition, the mutant was unable to compete with the wild-type strain in planta and in vitro. These results suggest that a functional rpoS gene is needed mainly for survival in a competitive environment and during stress conditions, and not for effective infection of plants.