Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Analysis of Models Predicting Morphology Transitions in Reactive Twin-Screw Extrusion of Bio-Based Polyester/Polyamide Blends

Immiscible PLA/PA11 of 80/20 and 50/50 wt% were compatibilized through addition of p-toluenesulfonic acid (TsOH) catalyst in reactive ultra-high speed twin-screw extrusion. Two mixing screw designs were compared for their ability to disperse the PA11 droplets in the PLA matrix as a function of screw speed up to 2000 rpm. The size and polydispersity of droplets of dispersed PA11 decreased when a high shear (HS) screw was used, whereas broad droplet size distribution was produced in the low shear (LS) screw. Two models predicting the droplet size dependence on shear rate, viscosity ratio and interfacial tension were fit to the experimental data. The Serpe model including volume fraction effects produced a better fit compared to the Wu model, which does not include volume fraction effects. Mechanical testing indicated that the compatibility of PLA/PA11 blends was improved through addition of TsOH catalyst for 50/50 wt% blends due to ester – amide exchange reactions at the interfaces in the immiscible PLA and PA11 phases. The enhancement of ductility was greater after processing with the LS screw configuration than the HS screw configuration. The inferior properties after high shear mixing were likely due to molecular weight degradation during processing. While the aggressive shear in the HS screw design resulted in fine dispersion, care should be taken to minimize degradation, especially for shear sensitive polymers.

The prevalence of significant left-right hip bone mineral density differences among black and white women

SUMMARY

In a cross-sectional retrospective study, we examined the prevalence of significant opposite hip bone mineral density difference among white and black women. Left-right hip bone mineral density difference was a common finding in both races, raising the possibility that osteoporosis can be missed if only one hip is imaged.

INTRODUCTION

We examined the prevalence of significant left-right hip bone mineral density (BMD) difference among black and white female subjects and its implications on the diagnosis of osteoporosis.

METHODS

This was a retrospective review of dual energy X-ray absorptiometry (DXA) data in black and white subjects age 50 years and older. One thousand four hundred seventy-seven scans obtained using a GE Lunar Prodigy scanner in dual hip mode were analyzed (24% black, 76% white). Significant left-right hip BMD difference was considered present when the subregion least significant change (LSC) was exceeded. Its prevalence was determined, along with consequences on the diagnosis of osteoporosis.

RESULTS

Significant differences in BMD were common in both races; the LSC was exceeded in 47% of the patients at the total hip, 37% at the femoral neck, and 53% at the trochanter. Diagnostic agreement was lower when the LSC was exceeded than when it was not. The LSC was exceeded in a statistically significant number of black and white patients with normal or osteopenic spines and unilateral hip osteoporosis.

CONCLUSIONS

Significant left-right hip BMD difference is a common finding among black and white women and can result in osteoporosis being missed if only one hip is imaged.

Clinical outcomes of renal transplant recipients treated with enteric-coated mycophenolic acid vs. mycophenolate mofetil as a switch agent using a primary steroid-free rapamune and microemulsion cyclosporine protocol

Since 2002 our transplant program has utilized a steroid free, cyclosporine (CSA)- and rapamycin (RAPA)-based maintenance immunosuppression regimen. In cases where it has been desirable to avoid the potential nephrotoxicity with this regimen we have used mycophenolic acid (MPA) as our "switch" drug of choice. Both mycophenolate mofetil (MMF) (Roche Inc., Nutley, NJ, USA) and enteric-coated MPA (ECM) (Novartis, East Hanover, NJ, USA) have been used. In this study, we retrospectively compared the tolerability of the two formulations of MPA. Thus we compared 103 recipients switched to RAPA/MMF (RMM group) to 114 switched to RAPA/ECM (REC group). There was a significantly higher incidence of patients requiring dose changes and drug discontinuation in the RMM group, as well as an increased frequency of dose changes. There were significantly more acute rejection episodes and kidney losses in the dose adjustment vs. no dose adjustment patients. However, when comparing the incidence of acute rejection and kidney loss between the RMM and REC groups, there was no significant difference. We conclude that in this cohort of recipients, the ECM formulation of MPA was better tolerated than the MMF formulation, resulting in fewer patients requiring dose adjustments or drug discontinuation.

A barley gene family homologous to the maize rust resistance gene Rp1-D

Many characterized plant disease resistance genes encode proteins which have conserved motifs such as the nucleotide binding site. Conservation extends across different species, therefore resistance genes from one species can be used to isolate homologous regions from another by employing DNA sequences encoding conserved protein motifs as probes. Here we report the isolation and characterization of a barley ( Hordeum vulgare L.) resistance gene analog family consisting of nine members homologous to the maize rust resistance gene Rp1-D. Five barley Rp1-D homologues are clustered within approximately 400 kb on chromosome 1(7H), near, but not co-segregating with, the barley stem rust resistance gene Rpg1; while others are localized on chromosomes 3(3H), 5(1H), 6(6H) and 7(5H). Analyses of predicted amino-acid sequences of the barley Rp1-D homologues and comparison with known plant disease resistance genes are presented.

Detection of Penicillium species in complex food samples using the polymerase chain reaction

Rapid identification of filamentous fungi is becoming increasingly important in food mycology both for monitoring the production process and for the identification of food spoilers. This paper describes the development and trial of two specific PCR primer sets. A 336 bp fragment from species belonging to Penicillium subgenus Penicillium was amplified by the primers ITS 212d and ITS 549. The other primer set, ITS 183 and ITS 401 specifically identified two species, Penicillium roqueforti and P. carneum, both known as spoilers in the bread industry, by amplification of a 300 bp fragment. The future perspectives of PCR based identification of filamentous fungi in food are discussed.