Less pronounced response to exercise in healthy relatives to type 2 diabetic subjects compared with controls

Healthy first-degree relatives with heredity of type 2 diabetes (FH+) are known to have metabolic inflexibility compared with subjects without heredity for diabetes (FH-). In this study, we aimed to test the hypothesis that FH+ individuals have an impaired response to exercise compared with FH-. Sixteen FH+ and 19 FH- insulin-sensitive men similar in age, peak oxygen consumption (V̇o2 peak), and body mass index completed an exercise intervention with heart rate monitored during exercise for 7 mo. Before and after the exercise intervention, the participants underwent a physical examination and tests for glucose tolerance and exercise capacity, and muscle biopsies were taken for expression analysis. The participants attended, on average, 39 training sessions during the intervention and spent 18.8 MJ on exercise. V̇o2 peak/kg increased by 14%, and the participants lost 1.2 kg of weight and 3 cm waist circumference. Given that the FH+ group expended 61% more energy during the intervention, we used regression analysis to analyze the response in the FH+ and FH- groups separately. Exercise volume had a significant effect on V̇o2 peak, weight, and waist circumference in the FH- group, but not in the FH+ group. After exercise, expression of genes involved in metabolism, oxidative phosphorylation, and cellular respiration increased more in the FH- compared with the FH+ group. This suggests that healthy, insulin-sensitive FH+ and FH- participants with similar age, V̇o2 peak, and body mass index may respond differently to an exercise intervention. The FH+ background might limit muscle adaptation to exercise, which may contribute to the increased susceptibility to type 2 diabetes in FH+ individuals.

First-degree relatives of type 2 diabetic patients have reduced expression of genes involved in fatty acid metabolism in skeletal muscle

CONTEXT

First-degree relatives of patients with type 2 diabetes (FH+) have been shown to have decreased energy expenditure and decreased expression of mitochondrial genes in skeletal muscle. In previous studies, it has been difficult to distinguish whether mitochondrial dysfunction and differential regulation of genes are primary (genetic) or due to reduced physical activity, obesity, or other correlated factors.

OBJECTIVE

The aim of this study was to investigate whether mitochondrial dysfunction is a primary defect or results from an altered metabolic state.

DESIGN

We compared gene expression in skeletal muscle from 24 male subjects with FH and 26 without FH matched for age, glucose tolerance, VO(2peak) (peak oxygen uptake), and body mass index using microarrays. Additionally, type fiber composition, mitochondrial DNA content, and citrate synthase activity were measured. The results were followed up in an additional cohort with measurements of in vivo metabolism.

RESULTS

FH+ vs. FH- subjects showed reduced expression of mitochondrial genes (P = 2.75 × 10(-6)), particularly genes involved in fatty acid metabolism (P = 4.08 × 10(-7)), despite similar mitochondrial DNA content. Strikingly, a 70% reduced expression of the monoamine oxidase A (MAOA) gene was found in FH+ vs. FH- individuals (P = 0.0009). Down-regulation of the genes involved in fat metabolism was associated with decreased in vivo fat oxidation and increased glucose oxidation examined in an additional cohort of elderly men.

CONCLUSIONS

These results suggest that genetically altered fatty acid metabolism predisposes to type 2 diabetes and propose a role for catecholamine-metabolizing enzymes like MAOA in the regulation of energy metabolism.

Estimation of electrode location in a rat motor cortex by laminar analysis of electrophysiology and intracortical electrical stimulation

While the development of microelectrode arrays has enabled access to disparate regions of a cortex for neurorehabilitation, neuroprosthetic and basic neuroscience research, accurate interpretation of the signals and manipulation of the cortical neurons depend upon the anatomical placement of the electrode arrays in a layered cortex. Toward this end, this report compares two in vivo methods for identifying the placement of electrodes in a linear array spaced 100 µm apart based on in situ laminar analysis of (1) ketamine-xylazine-induced field potential oscillations in a rat motor cortex and (2) an intracortical electrical stimulation-induced movement threshold. The first method is based on finding the polarity reversal in laminar oscillations which is reported to appear at the transition between layers IV and V in laminar 'high voltage spindles' of the rat cortical column. Analysis of histological images in our dataset indicates that polarity reversal is detected 150.1 ± 104.2 µm below the start of layer V. The second method compares the intracortical microstimulation currents that elicit a physical movement for anodic versus cathodic stimulation. It is based on the hypothesis that neural elements perpendicular to the electrode surface are preferentially excited by anodic stimulation while cathodic stimulation excites those with a direction component parallel to its surface. With this method, we expect to see a change in the stimulation currents that elicits a movement at the beginning of layer V when comparing anodic versus cathodic stimulation as the upper cortical layers contain neuronal structures that are primarily parallel to the cortical surface and lower layers contain structures that are primarily perpendicular. Using this method, there was a 78.7 ± 68 µm offset in the estimate of the depth of the start of layer V. The polarity reversal method estimates the beginning of layer V within ±90 µm with 95% confidence and the intracortical stimulation method estimates it within ±69.3 µm. We propose that these methods can be used to estimate the in situ location of laminar electrodes implanted in the rat motor cortex.

A phase 1 study of the selective cyclin dependent kinase inhibitor P276–00 in patients with advanced refractory neoplasms

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Background: In human cancers, genetic and epigenetic events result in over-expression of cyclins or absence or diminished levels of Cdk inhibitors, providing tumor cells with selective growth advantage. This has prompted the development of pharmacological Cdk inhibitors that could potentially produce anti-tumor effect. P276–00 is a selective Cdk4-D1 and Cdk1-B inhibitor. This study was designed to determine the maximum tolerated dose (MTD), toxicity profile, pharmacokinetics, and antitumour activity of P276–00 given intravenously to patients with advanced refractory solid tumours. Methods: P276–00 was administered in escalating doses to cohorts of eligible patients (pts), starting with a dose of 9 mg/m2 as a 30 minute iv infusion day 1 to 5, and day 8 to 12, q 3 weekly. To date 22 pts have been entered on the study (cohort 1 - 4 pts at 9 mg/m2, cohort 2 - 4 pts at 12.6 mg/m2, cohort 3 - 6 pts at 17.6 mg/m2, cohort 4 - 8 pts at 24.6 mg/m2) with PS 0–2, and mean age of 56 years. Pharmacokinetic profiles were obtained on cycle 1 days 1 and 5. Skin biopsies were obtained immediately prior to starting study treatment and on day 21 of cycle 2 and will be analyzed for Ki67, cleaved caspase 3, phospho-Rb, cyclin D1 and cdk4, and microarray. Results: To date dose limiting toxicity has occurred in one pt. Grade 3 fatigue occurred in 1 pt at 17.6 mg/m2. The most common drug-related adverse events, which were all grade 1 or 2, were fatigue, nausea, hypotension, sweating, and dry mouth. No Grade 3 biochemical toxicities have been reported so far. There have been no responses noted to date. 4 pts have stable disease after 2 cycles. Pharmacokinetic results: The Cmax, t1/2, and AUC0–8 on day 1 were as follows: 9 mg/m2- 315 ng/mL, 6.6 hr, 883 ng.h/mL; 12.6 mg/m2- 402 ng/mL, 5.5 hr, 848 ng.h/mL; 17.6 mg/m2- 589 ng/mL, 5.3 hr, 1289 ng.h/mL; 24.6 mg/m2- 621 ng/mL, 5.6 hr, 1286 ng.h/mL. Conclusions: P276–00 is well tolerated, but grade 3 fatigue has been noted in 1 pt at 17.6 mg/m2 dose level. We have observed confirmed stable disease in one patient. PK results indicate that at 9 mg/m2,12.6 mg/m2, 17.6 mg/m2 and 24.6 mg/m2 we are able to cross the cdk4 enzyme IC50 approximately 10, 13, 19 and 20 times and cross the anti-proliferative IC50 1.1, 1.4, 2.1 and 2.2 times respectively. Accrual continues at the 34.4 mg/m2 dose level.

No significant financial relationships to disclose.

A variant in the transcription factor 7-like 2 (TCF7L2) gene is associated with an increased risk of gestational diabetes mellitus

AIMS/HYPOTHESIS

Genetic and epidemiological studies suggest an association between gestational diabetes mellitus and type 2 diabetes. Both are polygenic multifactorial disorders characterised by beta cell dysfunction and insulin resistance. Our aim was to investigate whether common genetic variants that have previously been associated with type 2 diabetes or related phenotypes would also confer risk for gestational diabetes mellitus.

MATERIALS AND METHODS

In 1,881 unrelated pregnant Scandinavian women (649 women with gestational diabetes mellitus, 1,232 non-diabetic control subjects) we genotyped the transcription factor 7-like 2 (TCF7L2 rs7903146), adiponectin (ADIPOQ +276G > T), peroxisome-proliferator activated receptor, gamma 2 (PPARG Pro12Ala), PPARG-coactivator, 1 alpha (PPARGC1A Gly482Ser), forkhead box C2 (FOXC2 -512C > T) and beta3-adrenergic receptor (ADRB3 Trp64Arg) polymorphisms using TaqMan allelic discrimination assay or RFLP.

RESULTS

The CC, CT and TT genotype frequencies of the TCF7L2 rs7903146 variant differed significantly between women with gestational diabetes mellitus and control women (46.3, 43.6 and 10.1% vs 58.5, 35.3 and 6.2%, p = 3.7 x 10(-6), corrected p value [Pc] for multiple testing Pc = 2.2 x 10(-5)). The T-allele was associated with an increased risk of gestational diabetes mellitus (odds ratio 1.49 [95% CI 1.28-1.75], p = 4.9 x 10(-7) [Pc = 2.8 x 10(-6)]). Compared with wild-type CC-genotype carriers, heterozygous (CT-genotype) and homozygous (TT-genotype) carriers had a 1.6-fold (95% CI 1.26-1.93, p = 3.7 x 10(-5) [Pc = 0.0002]) and a 2.1-fold (95% CI 1.41-2.99, p = 0.0001 [Pc = 0.0008]) increased risk of gestational diabetes mellitus, respectively. The other polymorphisms studied were not significantly associated with gestational diabetes mellitus (ADIPOQ +276G > T: 1.17 [1.01-1.36], p = 0.039 [Pc = 0.23]; PPARG Pro12Ala: 1.06 [0.87-1.29], p = 0.53; PPARGC1A Gly482Ser: 0.96 [0.83-1.10], p = 0.54; FOXC2 -512C > T: 1.01 [0.87-1.16], p = 0.94; and ADRB3 Trp64Arg: 1.22 [0.95-1.56], p = 0.12).

CONCLUSIONS/INTERPRETATION

The TCF7L2 rs7903146 variant is associated with an increased risk of gestational diabetes mellitus in Scandinavian women.

Common variants in MODY genes increase the risk of gestational diabetes mellitus

AIMS/HYPOTHESIS

Impaired beta cell function is the hallmark of gestational diabetes mellitus (GDM) and MODY. In addition, women with MODY gene mutations often present with GDM, but it is not known whether common variants in MODY genes contribute to GDM.

SUBJECTS AND METHODS

We genotyped five common variants in the glucokinase (GCK, commonly known as MODY2), hepatocyte nuclear factor 1-alpha (HNF1A, commonly known as MODY3) and 4-alpha (HNF4A commonly known as MODY1) genes in 1,880 Scandinavian women (648 women with GDM and 1,232 pregnant non-diabetic control women).

RESULTS

The A allele of the GCK -30G-->A polymorphism was more common in GDM women than in control subjects (odds ratio [OR] 1.28 [95% CI 1.06-1.53], p=0.008, corrected p value, p=0.035). Under a recessive model [AA vs GA+GG], the OR increased further to 2.12 (95% CI 1.21-3.72, p=0.009). The frequency of the L allele of the HNF1A I27L polymorphism was slightly higher in GDM than in controls (1.16 [95% CI 1.001-1.34], p=0.048, corrected p value, p=0.17). However, the OR increased under a dominant model (LL+IL vs II; 1.31 [95% CI 1.08-1.60], p=0.007). The rs2144908, rs2425637 and rs1885088 variants, which are located downstream of the primary beta cell promoter (P2) of HNF4A, were not associated with GDM.

CONCLUSIONS/INTERPRETATION

The -30G-->A polymorphism of the beta-cell-specific promoter of GCK and the I27L polymorphism of HNF1A seem to increase the risk of GDM in Scandinavian women.

Magnitude of interference after diphtheria-tetanus toxoids-acellular pertussis/Haemophilus influenzae type b capsular polysaccharide-tetanus vaccination is related to the number of doses administered

We compared the antibody response to Haemophilus influenzae type b capsular polysaccharide (PRP) after 1, 2, or 3 doses of a diphtheria-tetanus toxoids-acellular pertussis (DTaP) vaccine combined with a PRP-tetanus conjugate (PRP-T) vaccine, followed by separate injections of DTaP and PRP-T vaccines for the last 1 or 2 doses. Healthy infants were recruited from pediatric practices and were immunized according to recommended schedules. A significant decrease in the mean anti-PRP (from 5.25 to 2.68 microg/mL) and anti-tetanus toxoid antibody responses (from 0.13 to 0.09 Eq/mL) was observed as the number of doses of the DTaP/PRP-T combination vaccine increased (P<.02 and P=.01, respectively). In contrast, the mean anti-diphtheria toxoid antibody response increased with increasing numbers of DTaP/PRP-T doses (P=.0001). The effects of interference were not eliminated by the completion of the primary series with 1 or 2 doses of the DTaP and PRP-T vaccines given separately.

Differential effects of IH636 grape seed proanthocyanidin extract and a DNA repair modulator 4-aminobenzamide on liver microsomal cytochrome 4502E1-dependent aniline hydroxylation

Previous studies from our laboratories have linked the protective abilities of IH636 grape seed proanthocyanidin extract (GSPE) with inactivation of anti-apoptotic gene bcl-XL, and modification of several other critical molecular targets such as DNA-damage/DNA-repair, lipid peroxidation and intracellular Ca2+ homeostasis. Especially, GSPE provided dramatic protection against acetaminophen (APAP)-induced hepatotoxicity, significantly increased bcl-XL expression in the liver, and antagonized both necrotic and apoptotic deaths of liver cells in vivo. However, it was not clear from this study whether anti-apoptogenic and anti-necrotic effects of GSPE were: (i) due to its interference with endonuclease activity, (ii) due to its antioxidant effect, or, (iii) due to its ability to inhibit microsomal drug metabolizing enzyme(s), such as CYP-4502E1. Since CYP-4502E1 primarily metabolizes acetaminophen in mice and rats, this study specifically focused on CYP-4502E1's catalytic activity in vitro. Overall this investigation compared the in vitro aniline hydroxylation patterns of: (i) in vivo GSPE-exposed and unexposed (control) mouse liver microsomes, (ii) induced (1% acetone in drinking water for 3 days) and uninduced rat liver microsomes in the presence and absence of GSPE in vitro, and (iii) control rat liver microsomes in the presence of an anti-APAP agent 4-aminobenzamide (4-AB) in vitro. For the in vivo assessment, male B6C3F1 mice were fed GSPE diet (ADI 100 mg/kg body wt) for 4 weeks, and liver microsomes were isolated from both control and GSPE-fed mice for aniline hydroxylation, a specific marker of CYP-4502E1 activity. Data show that hydroxylation was 40% less in microsomes from GSPE-exposed livers compared to control microsomes. Similarly, when rat liver microsomes were incubated with various concentrations of GSPE in vitro (100 and 250 microg/ml), aniline hydroxylation was inhibited to various degrees (uninduced: 40 and 60% and induced: 25 and 50%, respectively with 100 and 250 microg/ml). Influence of GSPE on hydroxylation patterns were compared with another hepatoprotective agent 4-aminobenzamide (4-AB), a well-known modulator of nuclear enzyme poly(ADP-ribose) polymerase, and the data shows that 4-AB did not alter aniline hydroxylation at all. Collectively, these results may suggest that GSPE has the ability to inhibit CYP-4502E1, and this is an additional cytoprotective attribute, in conjunction with its novel antioxidant and/or antiendonucleolytic potential.

Absence of a significant interaction between a Haemophilus influenzae conjugate vaccine combined with a diphtheria toxoid, tetanus toxoid and acellular pertussis vaccine in the same syringe and inactivated polio vaccine

BACKGROUND

We compared the antibody response to Haemophilus influenzae type b capsular polysaccharide (PRP) after three doses of a diphtheria toxoid, tetanus toxoid and acellular pertussis vaccine (DTaP) combined with a PRP-tetanus conjugate (PRP-T) in infants randomized to receive oral polio vaccine (OPV) or inactivated polio vaccine (IPV). The polio vaccine was given separately at the same visit.

METHODS

Three hundred fifty-six infants from pediatric practices in suburban Chicago and New Orleans were randomized into two groups. Group A received OPV at 2 and 4 months of age; Group B received IPV at 2 and 4 months of age. Both groups received DTaP/PRP-T at 2, 4 and 6 months of age and hepatitis B vaccine at 2 and 4 months of age. A serum sample was obtained before immunization (age 2 months) and 1 month after 3 doses of DTaP/PRP-T (age 7 months). Sera were assayed for antibody responses to all relevant vaccine antigens.

RESULTS

No significant vaccine antigen interference was found when polio immunization was provided by IPV or OPV for anti-PRP, diphtheria, tetanus or pertussis antibodies. OPV recipients had a significantly higher mean antibody response to serotype 1 (P = 0.03) and 2 (P = 0.0001) poliovirus.

CONCLUSION

Whether polio immunization was accomplished with IPV or OPV did not significantly influence the antibody responses in sera obtained at 7 months of age for anti-PRP, anti-diphtheria and anti-tetanus toxoid antibodies and antibodies to pertussis antigens, when DTaP/PRP-T was given in the primary series.

Organization, sequence and regulation of expression of the murine Hoxa-7 gene

The genomic sequence of Hoxa-7 (encoding the HOXa-7 homeobox protein), including the coding region (0.7 kb), flanked by a 5'-upstream region (2.8 kb), a 3'-downstream region (1 kb) and interrupted by an intron (995 bp), was determined. Northern blot analysis indicated the transcript size of Hoxa-7 to be 2.1-2.4 kb. Reverse transcription-PCR and primer extension analysis established the 5'-boundary of the mRNA to be in the region 1166 nt upstream from the start codon. Transient transfection of various Hoxa-7::cat constructs in NIH 3T3 cells was used to characterize the transcriptional activity of the 5'-flanking region of the gene. Constructs containing 544, 274 and 71 bp of the region upstream from the transcription start point (tsp) exhibited 78, 203 and 407%, respectively, of the activity shown by a control construct containing 739 bp of the upstream region. These data suggested the presence of negative regulatory elements in the region from 544 to 71 bp upstream from the tsp.

Ring chromosome 20 and possible assignment of the structural gene encoding human carboxypeptidase-L to the distal segment of the long arm of chromosome 20

We report on a 14-year-old boy with ring chromosome 20. Clinical manifestations included postnatal growth retardation, epilepsy, microcephaly, behaviour disorder, minor facial anomalies, small sella turcica, possible partial growth hormone deficiency, and mental retardation. A decreased activity of enzyme carboxypeptidase-L/protective protein (CP/PP) in cultured fibroblasts was demonstrated in our patient and a patient with a karyotype 46,XY,-14, + der(14)t(14;20)(14pter----14q32.3::20q13.1----20qter)m at. This suggests possible assignment of the CP/PP gene to the distal segment of 20q.