Open versus laparoscopic pyloromyotomy for pyloric stenosis: a meta-analysis of randomized controlled trials

OBJECTIVE

Aim of the study was to compare the outcomes after laparoscopic pyloromyotomy (LP) with those of open pyloromyotomy (OP) for infantile pyloric stenosis.

METHOD

We conducted searches until February 2009 in multiple databases and identified randomized controlled trials comparing LP with OP for pyloric stenosis. Results were expressed using the odds ratio (OR) for categorical variables and standard weighted mean differences (SMD) for continuous outcomes. Study quality was assessed using the Cochrane Handbook 5.0.1 guidelines and statistical analysis was performed using RevMan 5.0.8 software.

RESULTS

3 studies totaling 492 infants were included. The results showed no significant differences in complications between the groups with regard to wound infection (OR: 1.77, 95% CI 0.58-5.35), mucosal perforations (OR: 0.96, 95% CI: 0.22-4.26), incisional hernia or granuloma (OR: 1.39, 95% CI: 0.41-4.73), incomplete pyloromyotomy (OR: 0.13, 95% CI: 0.02-1.07), substantial vomiting (OR: 0.67, 95% CI: 0.30-1.52) and total complications (OR: 0.91, 95% CI: 0.54-1.53). Although the combined result of 2 studies also indicated an insignificant discrepancy in time-related outcomes for full time to feeds, length of stay after surgery and operating time (SMD: 0.78, 95% CI: -0.50-2.06; SMD: 1.27, 95% CI: -1.56-4.10; SMD: -0.46, 95% CI: -1.11-0.20, respectively), another study indicated shorter times for LP procedures (p=0.002, 0.027, and 0.008, respectively).

CONCLUSIONS

Only a few trials were available for analysis. Heterogeneity was seen between studies, but the available trials were of high quality. The present study shows that both OP and LP are equally safe and effective procedures for the management of pyloric stenosis in children. However, there was a trend in LP toward shorter time time-related outcomes.

In-Situ Neutron Diffraction Studies of Mixed Conducting Sr-Fe-Co-O Materials

SrFeCo0.5Oy has been identified as a potential dense ceramic membrane material used for gas separation at elevated temperatures. Neutrons play an important role in the study of such materials, particularly due to the favorable scattering lengths of Fe, Co and O. In-situ neutron diffraction experiments allow these materials to be studied under a wide range of temperatures and oxygen partial pressures. Results indicate very complex behavior of individual phases during synthesis and under operational membrane conditions.

The expression of frizzled-3 receptor in colorectal cancer and colorectal adenoma

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Background: Wnt signaling is well known for its role in colorectal cancer (CRC) formation through transcriptional activities of nuclear β-catenin. Although activation of Wnt signaling depends on specific Wnt/Frizzled receptors (FZD) combinations, the specificity of the interaction and the role of FZD in that particular interaction are still unknown. Among the 10 Wnt receptors of the FZD protein family, FZD-3 is involved in neurodevelopmental abnormalities and gastric cancer carcinogenesis. However, the expression of FZD-3 in CRC is not clear. Therefore in this study, we examined the expression of FZD-3 in CRC cell lines and CRC patient tissues with various pathological stages. The information obtained will be important for us to understand the role of FZD-3 in the development of CRC.

Methods: FZD-3 mRNA expression was studied in CRC metastatic SW620, primary SW480 and normal CCD18co cell lines using quantitative real-time polymerase chain reaction with primers and a Taqman minor grove binder probe (Applied Biosystems, Foster City, USA). Moreover, paraffin-embedded specimens of 40 CRC patient tissues, 25 colorectal adenoma (CA) tissues were retrieved from the Department of Pathology, Queen Elizabeth Hospital, Hong Kong Special Administrative Region for FZD-3 immunostaining using an anti-FZD-3 antibody (Catalog no: MAB1001, R&D systems Inc., Minneapolis, USA) in an automatic Ventana Benchmark XT immunostainer (Ventana Medical Systems Inc., Tucson, USA).

Results: FZD-3 mRNA was up-regulated in metastatic SW620 cell line (fold-change: 622) and in primary SW480 cell line (fold-change: 820) when compared to that in normal CCD18co cell line. Furthermore, immunostaining showed that FZD-3 protein was expressed in 100% (40/40) of CRC specimens and 84% (21/25) of CA specimens. Detailed analysis showed that FZD-3 protein was significantly up-regulated in CRC, CA when compared to their adjacent normal colorectal epithelial tissues (p < 0.0005, Wilcoxon matched pairs test).

Conclusions: This study provided evidence that FZD-3 is involved in CRC carcinogenesis and it is a potential therapeutic target in CRC.

No significant financial relationships to disclose.

Detecting early bone changes using in vivo micro-CT in ovariectomized, zoledronic acid-treated, and sham-operated rats

SUMMARY

This study monitored in vivo the effect on bone microarchitecture of initiating antiresorptive treatment with zoledronic acid in rats at 2 weeks following ovariectomy, an early phase at which major degenerative bone changes have been found to occur. The treatment still facilitated the full reversal of cancellous bone loss in rat tibia, highlighting the importance of the time point of initiation of antiresorptive treatment.

INTRODUCTION

Injection of zoledronic acid in rats at time of ovariectomy has been found to fully preserve tibial bone microarchitecture over time, whereas injection at 8 weeks after ovariectomy has shown partial bone recovery. This study investigated the effect on microarchitecture of initiating antiresorptive treatment in the early phase following ovariectomy, at 2 weeks, a time point at which major degenerative changes in the bone have been found to occur.

METHODS

Female Sprague-Dawley rats were divided into ovariectomized group, ovariectomized group treated with zoledronic acid, and sham-operated group. In vivo micro-CT scanning of rat tibiae and morphometric analysis were performed at 0, 2, 4, 8, and 12 weeks after ovariectomy, with zoledronic acid treatment beginning 2 weeks after ovariectomy. Data were first analyzed with repeated measures analysis of variance (longitudinal study design) and then without repeated measures (cross-sectional study design).

RESULTS

The ovariectomized group demonstrated dramatic bone loss, first detected at week 2. Conversely, at week 4, the zoledronic acid-treated group returned microstructural parameters to baseline values. Remarkable increases in bone parameters were found after 6 weeks of treatment and maintained similar to sham group until the end. The longitudinal study design provided earlier detection of bone changes compared to the cross-sectional study design.

CONCLUSIONS

Treatment with zoledronic acid as late as 2 weeks after ovariectomy still facilitates the full reversal of cancellous bone loss in the rat tibia.

Capecitabine/oxaliplatin as first-line treatment for metastatic colorectal cancer: a meta-analysis

OBJECTIVE

A meta-analysis of randomized controlled trials (RCT) was carried out to determine the efficacy and safety of capecitabine plus oxaliplatin (CAPOX) or fluorouracil plus oxaliplatin (FUOX) as first-line treatment for metastatic colorectal cancer (MCRC).

METHOD

A literature search was conducted of the Cochrane Controlled Trials Register Databases, Medline, Embase, ISI databases and Chinese Biomedical Literature Database without exclusion of material published in any language. RCTs conducted between 1998 and 2008 of CAPOX compared with FUOX regimens were considered for inclusion. Statistical analyses were carried out using RevMan software.

RESULTS

Ten RCTs were included, involving 3208 patients. The meta-analysis showed that there were no statistically significant differences in tumour response rate (RR, 0.93; 95% CI, 0.87-1.01; P = 0.09), progression-free survival (PFS) (RR, 0.98; 95% CI, 0.94-1.01; P = 0.19), and overall survival (OS) (RR, 1.02; 95% CI, 0.97-1.07; P = 0.47) between CAPOX and FUOX regimen. However, symptoms of thrombocytopenia and hand-foot syndrome (HFS) were increased in the CAPOX regimen (RR, 1.89; 95% CI, 1.33-2.69; P = 0.0004 and RR, 3.40; 95% CI, 2.25-5.15; P < 0.00001 respectively), while neutropenia and leucopenia occurred more frequently in the FUOX regimen (RR, 0.29; 95% CI, 0.15-0.55; P = 0.0002 and RR, 0.41; 95% CI, 0.18-0.95; P = 0.04 respectively).

CONCLUSION

CAPOX was equivalent to FUOX in terms of tumour response rate, progression-free survival (PFS), and OS in first-line treatment for patients with MCRC, which may be considered as standard first-line treatment in patients with MCRC.

Bioengineered skin in diabetic foot ulcers

OBJECTIVE

Bioengineered skin (BS) has been shown to play an important role in the treatment of diabetic foot ulcers (DFUs). Whether BS in the therapy of DFU can improve the outcomes still remains uncertain. We performed a quantitative meta-analysis of available randomized controlled trials to determine the effectiveness and safety of BS in the treatment of patients with DFUs.

DESIGN AND METHODS

Comprehensive search strategies of various electronic databases were used for this study to evaluate the effectiveness and safety between BS and conventional treatment (CT) in patients with DFU, and only randomized controlled trials were adopted in our review. Search terms included 'bioengineered skin', 'tissue-engineering skin', 'human-tissue graft', 'human-skin device', 'living-skin equivalent' and 'diabetic foot', 'diabetic ulcer', 'diabetic wound'. Analysis outcomes included complete wound closure, complications, ulcer recurrence and adverse severe events (ASEs).

RESULTS

Seven randomized controlled trials on BS vs. CT were included, and 880 participants met inclusion criteria. Pooled analysis showed a significant effectiveness and safety advantages for BS treatment compared to CT for patients with DFUs. In analysis of complications, only statistically significant difference of infection was noted. And no included trials reported ASEs related to these treatments.

CONCLUSIONS

Based on the meta-analysis, patients with DFUs may benefit from the BS because of its high effectiveness and safety and reduced risk for infections in comparison to CT.

Glassy thermal conductivity in the two-phase Cu(x)Ag(3-x)SbSeTe(2) alloy and high temperature thermoelectric behavior

We have measured the thermal transport properties over the temperature range 1.8 K<T<700 K of a two-phase alloy synthesized by reacting AgSbTe(2) and Ag(2)Se in a 1:1 molar ratio. Typical electrical resistivity values at 700 K are in the range ∼4 mΩ cm≤ρ≤20 mΩ cm, while low thermal conductivity values (κ<1 W m(-1) K(-1)) were obtained. We find that the thermal conductivity of this crystalline alloy has a temperature dependence strikingly similar to those of amorphous solids. In addition the thermal conductivity, thermopower, and electrical resistivity decouple. This result makes it possible to optimize thermoelectric performance by minimizing the electrical resistivity. It is therefore envisaged that this system has potential as a high performance bulk thermoelectric.

Fitness and Competitive Ability of an Azoxystrobin-Resistant G143A Mutant of Magnaporthe oryzae from Perennial Ryegrass

Development of azoxystrobin resistance in Magnaporthe oryzae from perennial ryegrass has been reported in certain locations in the United States, and possible development of resistance in additional areas is a major concern in the golf course industry. The study was undertaken to evaluate the relative fitness and competitive ability of a field-collected azoxystrobin-resistant G143A mutant by comparing it with a wild-type strain using detached perennial ryegrass blades. A fitness comparison experiment indicated that the disease severity of the wild-type strain was significantly higher than that of the mutant; however, the mutant produced greater secondary inoculum. When inoculated with three mixed populations of resistant and wild-type strains at different ratios, the production of conidia by the wild-type strain increased and that of the mutant decreased after infection occurred in all three populations tested. In an experiment on the effect of various fungicides on the population initially containing 5% of the mutant, preventive application of azoxystrobin allowed 5% of the mutant to dominate the population after the infection. However, other non-quinone outside inhibitor fungicides and mixtures of azoxystrobin with contact fungicides eliminated the entire mutant. This study demonstrates that the wild-type strain of M. oryzae has a competitive advantage over the mutant within the environment tested. Mixtures and alternations of fungicides with different modes of actions may prevent rapid build-up of resistance in the gray leaf spot pathosystem.

Pazopanib and lapatinib in patients with relapsed malignant glioma: Results of a phase I/II study

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Background: Pazopanib (paz) is an oral angiogenesis inhibitor targeting VEGFR, PDGFR, and c-kit; and lapatinib (lap) is an oral tyrosine kinase inhibitor of EGFR (ErbB1) and HER-2 (ErbB2). Combination of VEGFR, PDGFR, and ErbB1 inhibitors may provide synergistic antitumor activity in malignant glioma. Phase I determined the optimally tolerated regimen (OTR) of paz and lap when given with enzyme-inducing anticonvulsants (EIACs). Phase II, which evaluated the efficacy of daily paz/lap (400 mg/1000mg) in relapsed grade 4 glioma without EIACs, was previously reported. Methods: Patients (pts) with grade 3 or 4 glioma, on EIACs, and with adequate organ function were eligible. Doses of paz and lap were escalated in a 3 + 3 design. OTR was defined as the highest dose of paz/lap at which no more than 1 of 6 pts had dose limiting toxicity (DLT) and target concentrations were achieved. Results: 32 pts have been enrolled at doses of paz/lap (mg, daily unless specified) of 200/1500 (N = 4), 800/1500 (N = 6), 800/500 bid (N = 5), 800/750 bid (N = 7), 800/1000 bid (N = 6), and 600 bid/1000 bid (N = 4). Data on 28 pts: the most common adverse events (AEs) were: fatigue (25%); diarrhea (25%); headache (21%); ALT increase (18%); nausea (18%); and insomnia (14%). Hepatobiliary lab abnormalities were reversible, uncomplicated, and included: AST elevation (11%), hyperbilirubinemia (7%), ALT elevation (36%; 7% Gr 3), and Alk phos elevation (14%). DLTs were elevated liver enzymes (800/1500; 1 pt), elevated lipase (800/750 bid; 1 pt) and thrombocytopenia, fatigue, diarrhea, confusion (800/1000 bid; 1 pt). 2 pts dose reduced and 3 pts had a dose interruption. At 600 bid/1000 bid, the target paz Cmin of 17.5 μg/mL was achieved; median lap Cmin of 0.447 μg/mL approached the target of 0.5 μg/mL. Phase I best response (MacDonald criteria) was PR in 3 pts (11%) and SD ≥ 8 weeks in 5 pts (18%). Two pts remain on the phase II, at 21 months (PR) and 23 months (CR) of therapy. Conclusions: The paz/lap combination has a manageable safety profile with a preliminary OTR with EIACs of paz 600 mg bid/ lap 1000 mg bid. EIACs decreased plasma paz and lap concentrations. Responses and lengthy periods without disease progression were seen in some pts in phase I and II.

[Table: see text]

Does severity of underlying chronic liver disease (CLD) affect treatment outcome of hepatocellular carcinoma (HCC) patients undergoing systemic chemotherapy (CT)?

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Background: HCC is a common cause of morbidity and mortality. CT has been one of the treatments offered to patients (pts) who are not candidate of curative surgery. Treatment of HCC could be complicated by underlying CLD. In this study, we aimed to assess pre-CT severity of CLD on treatment outcome of HCC pts who were entered into our previously reported phase III prospective randomized CT study (J Natl Cancer Inst 2005). Methods: The severity of CLD for each pt was arbitrary assessed by adopting the Child-Pugh's classification. Patients’ characteristics were compared. Treatment outcomes in terms of responses, survival and treatment-related toxicities (NCI CTC) were compared. Results: 160 were Child's A; 28 were Child's B. Proportion of pts with cirrhosis (45% vs 71%, P=0.01) and pre-CT bilirubin level (11 vs. 15 umol/l, p=0.02) were significantly higher, while age (52 vs 45 yrs, p=0.05) and albumin level (35 vs 30 g/l, p<0.0001) were significantly lower among Child's B pts. For Child's A and B pts: the median no. of CT cycles received were 4.0 vs 2.5 (p=0.01), the response rates were 17% vs 8.3% (p=0.28), the median survival were 21 vs 10.7 months (p= 0.002). When toxicity during CT were compared, Child's B pts had significantly higher rate of grade 3/4 neutropenia (0.6% vs. 7.1%, p=0.05), hyperbilirubinaemia (11.9% vs. 28.6%, p=0.02), hyponatremia (3.1% vs. 3.6%, p=0.001) and gastrointestinal bleeding (3.1% vs. 17.9%, p=0.001). Conclusions: Child's B HCC pts experienced increased treatment-related toxicities during CT. This has probably led to a shorter duration of CT and a lower response rate to CT. Their shorter survival could also be attributed to the severity of underlying CLD. Future trials on systemic therapy in HCC patients may need to consider stratifying patients according to severity of CLD.

No significant financial relationships to disclose.

Troglitazone suppresses transforming growth factor-beta1-induced collagen type I expression in keloid fibroblasts

BACKGROUND

Peroxisome proliferator-activated receptor (PPAR)-gamma agonists are increasingly used in patients with diabetes and some studies have suggested a beneficial effect on organ fibrosis. However their effects on dermal fibrosis in keloids are unknown.

OBJECTIVE

To investigate the effect of the PPAR-gamma agonist troglitazone on transforming growth factor (TGF)-beta1-induced collagen type I expression in keloid fibroblasts.

METHODS

Keloid fibroblasts were cultured and exposed to different concentrations of troglitazone in the presence of TGF-beta1. The mRNA expression of PPAR-gamma was determined by semiquantitative reverse transcriptase-polymerase chain reaction. The protein of PPAR-gamma, Smad2, Smad3, phoshpo-Smad2/3 and collagen type I was determined by Western blotting and collagen synthesis was evaluated by measuring (3)H-proline incorporation. The effect of troglitazone on cell viability was evaluated by the colorimetric conversion of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide.

RESULTS

PPAR-gamma was expressed at a moderate level in keloid fibroblasts. Troglitazone depressed TGF-beta1-stimulated collagen type I expression and collagen synthesis in keloid fibroblasts in a concentration-dependent manner. Moreover, troglitazone inhibited expression and phosphorylation of TGF-beta1-induced Smad2/3. Cell viability was unaffected. These inhibitory effects of troglitazone were reversed by the PPAR-gamma-specific antagonist GW9662.

CONCLUSIONS

Our data suggest that PPAR-gamma is present in keloid fibroblasts and PPAR-gamma activation inhibits TGF-beta1-induced collagen type I expression at least in part by decreasing collagen synthesis. PPAR-gamma may be a promising therapeutic target for keloids.

Niche-specificity and the variable fraction of the Pectobacterium pan-genome

We compare genome sequences of three closely related soft-rot pathogens that vary in host range and geographical distribution to identify genetic differences that could account for lifestyle differences. The isolates compared, Pectobacterium atrosepticum SCRI1043, P. carotovorum WPP14, and P. brasiliensis 1692, represent diverse lineages of the genus. P. carotovorum and P. brasiliensis genome contigs, generated by 454 pyrosequencing ordered by reference to the previously published complete circular chromosome of P. atrosepticum genome and each other, account for 96% of the predicted genome size. Orthologous proteins encoded by P. carotovorum and P. brasiliensis are approximately 95% identical to each other and 92% identical to P. atrosepticum. Multiple alignment using Mauve identified a core genome of 3.9 Mb conserved among these Pectobacterium spp. Each core genome is interrupted at many points by species-specific insertions or deletions (indels) that account for approximately 0.9 to 1.1 Mb. We demonstrate that the presence of a hrpK-like type III secretion system-dependent effector protein in P. carotovorum and P. brasiliensis and its absence from P. atrosepticum is insufficient to explain variability in their response to infection in a plant. Additional genes that vary among these species include those encoding peptide toxin production, enzyme production, secretion proteins, and antibiotic production, as well as differences in more general aspects of gene regulation and metabolism that may be relevant to pathogenicity.

Quark-hadron duality in neutron (3He) spin structure

We present experimental results of the first high-precision test of quark-hadron duality in the spin-structure function g_{1} of the neutron and 3He using a polarized 3He target in the four-momentum-transfer-squared range from 0.7 to 4.0 (GeV/c);{2}. Global duality is observed for the spin-structure function g_{1} down to at least Q;{2}=1.8 (GeV/c);{2} in both targets. We have also formed the photon-nucleon asymmetry A1 in the resonance region for 3He and found no strong Q2 dependence above 2.2 (GeV/c);{2}.

Renal elimination of a novel and potent αvβ3integrin antagonist in animals

Compound A (3-{2-oxo-3-[3-(5,6,7,8-tetrahydro-[1,8]napthyridin-2-yl)propyl]-imidazolidin-1-yl}-3(S)-(6-methoxy-pyridin-3-yl)propionic acid), a hydrophilic zwitter-ion, is a potent and selective alphavbeta3 integrin antagonist currently under clinical development for the treatment of osteoporosis. The mechanism of renal excretion of compound A was investigated using a combination of in vivo and in vitro approaches. In rats, renal excretion of compound A involved tubular secretion; ratios between renal clearance, corrected for unbound fraction in plasma (CLr,u) and glomerular filtration rate (GFR) were greater than unity (2-5). The tubular secretion of compound A was saturable at high plasma levels (> 26 microM), and was inhibited significantly, although modestly (about twofold) by relatively high plasma concentrations of the organic anion PAH (160 microM) and the cation cimetidine (about 400 microM), but not by the P-gp inhibitor quinidine (about 50 microM). However, compound A (about 100 microM) had a minimal effect on CLr/GFRs for cimetidine and PAH. In rhesus monkeys, renal elimination of compound A also involved tubular secretion, with a CLr,u/GFR ratio of about 30. The renal secretion of compound A was not affected by either cimetidine (about 120 microM) or PAH (about 80 microM). Similarly, compound A (about 40 microM) had a minimal effect on the renal tubular secretion of both cimetidine and PAH. At the doses studied, neither rat nor monkey plasma protein binding of compound A, cimetidine or PAH was affected in the presence of each other. In vitro transport studies showed that compound A was not a substrate for P-gp in the Caco-2, human MDR1 and mouse mdr1a transfected LLC-PK1 cell lines. In an uptake study using rOAT1 and rOAT3 transfected HEK cell lines, compound A was shown to be a substrate for rat OAT3 (Km= 15 microM), but not rat OAT1. The results suggest that the tubular secretion of compound A is not mediated by P-gp, but rather is mediated, at least in part, via the organic anion transporter OAT3, the renal transporter shown to be capable of transporting both the organic anion PAH and the organic cation cimetidine. Although there is a possibility for pharmacokinetic interactions between compound A and substrates or inhibitors of OAT3, at the renal excretion level, the magnitude of interaction would likely be modest in humans at clinically relevant doses.

Genetic analysis and gene mapping of a rice few-tillering mutant in early backcross populations (Oryza sativa L.)

A rice mutant, G069, characteristic of few tiller numbers, was found in anther culture progeny from the F(1) hybrid between an indica-japonica cross, Gui630x02428. The mutant has another two major features: delayed tillering development and yellowing apex and margin on the mature leaves. As a donor parent, G069 was further backcrossed with the recurrent parent,02428, for two turns to develop aBC (2)F(2) population. Genetic analysis in the BC (2)F(2) population showed that the traits of few-tillering and yellowing apex and margin on the mature leaves were controlled by one recessive gene. A pool of equally mixed genomic DNA, from few-tillering individual plants in BC (2)F(2), was constructed to screen polymorphism with simple sequence repeat (SSR) markers in comparison with the 02428 genome. One SSR marker and three restriction fragment length polymorphism (RFLP) markers were found possibly linked with the recessive gene. By using these markers, the gene of few-tillering was mapped on chromosome 2 between RFLP marker C424 and S13984 with a genetic distance of 2.4 cM and 0.6 cM, respectively. The gene is designated ft1.

Development of methods for detection and quantification of avian influenza and Newcastle disease viruses in compost by real-time reverse transcription polymerase chain reaction and virus isolation

Composting has been used for disposal of poultry carcasses and manure following outbreaks caused by avian influenza virus (AIV) and Newcastle disease virus (NDV), but methods are needed to test for survival of the viruses in compost to ensure biosecurity. Methods developed in the present study include extracting viruses from compost and purifying viral RNA. The extracted viruses were detected by virus isolation using embryonated chicken eggs, and the purified RNA was detected by real-time reverse transcription PCR (RRT-PCR). The virus isolation and the RRT-PCR methods were evaluated with 3 compost preparations that were produced from chicken manure mixed with corn silage, wood shavings, or wheat straw. The detection limits of both methods were 1,700 and 1,000 embryo lethal doses of AIV and NDV per gram of compost, respectively. The copy number of viral RNA quantified by RRT-PCR was highly correlated with the amount of virus in compost. The results suggested that the RRT-PCR method may be used as an alternative to the virus isolation method for rapid detection and accurate quantification of AIV and NDV in compost.

Plasma and dietary vitamin E in relation to insulin secretion and sensitivity

AIM

In the Insulin Resistance and Atherosclerosis Study (IRAS), we have previously shown a protective effect of plasma alpha-tocopherol concentration against diabetes incidence among persons not taking vitamin E supplements. The biologic mechanism for such a protective effect could involve improvement in either insulin sensitivity (S(I)), insulin secretion or both. Thus, we examined vitamin E in relation to insulin secretion and S(I) among persons not taking vitamin E supplements.

METHODS

This analysis included 457 adults aged 40-69 years without a previous diabetes diagnosis or vitamin E supplement use at baseline and seen at the 5-year follow-up examination. Baseline nutrient intake was estimated from a validated 1-year food frequency questionnaire; plasma levels of alpha-tocopherol were also assessed. At follow up, a frequently sampled intravenous glucose tolerance test determined S(I), acute insulin response to glucose (AIR), and the disposition index (DI) was calculated as the sum of the log-transformed AIR and S(I) to reflect pancreatic compensation for insulin resistance.

RESULTS

In multivariable regression analyses, no relationship was observed for vitamin E intake and either S(I), AIR or DI. However, plasma alpha-tocopherol concentration was positively associated with log-transformed S(I) (beta= 0.27 +/- 0.09, p < 0.01) and DI (beta= 0.41 +/- 0.14, p < 0.01), but not with log-transformed AIR.

CONCLUSIONS

Plasma concentration of alpha-tocopherol may improve S(I) and pancreatic compensation for insulin resistance, although it does not seem to be related to acute insulin response.