The Effects of Fetal Gender on Maternal and Fetal Insulin Resistance

Objective

Gender plays a role in the development of a number of cardiovascular and metabolic diseases and it has been suggested that females may be more insulin resistant in utero. We sought to assess the relationship between infant gender and insulin resistance in a large pregnancy cohort.

Study Design

This is a secondary analysis of a cohort from the ROLO randomized control trial of low GI diet in pregnancy. Serum insulin, glucose and leptin were measured in early pregnancy and at 28 weeks. At delivery cord blood C-peptide and leptin were measured. A comparison of maternal factors, fetal biometry, insulin resistance and leptin was made between male and female offspring. A multivariate regression model was built to account for the possible effects of maternal BMI, birthweight and original study group assignment on findings.

Results

A total of 582 women were included in this secondary analysis, of whom 304 (52.2%) gave birth to male and 278 (47.8%) gave birth to female infants. Compared to male infants at birth, female infants were significantly lighter, (3945 ± 436 vs. 4081± 549g, p<0.001), shorter in length (52.36 ± 2.3 vs. 53.05 ± 2.4cm, p<0.001) and with smaller head circumferences (35.36 ± 1.5 vs. 36.10 ± 1.1cm, p<0.001) than males. On multiple regression analysis, women pregnant with female fetuses were less insulin resistant in early pregnancy, i.e. had lower HOMA indices (B = -0.19, p = 0.01). Additionally female fetuses had higher concentrations of both cord blood leptin and C-peptide at birth when compared to male offspring (B = 0.38, p<0.001 and B = 0.31, p = 0.03 respectively).

Conclusion

These findings suggest gender is a risk factor for insulin resistance in–utero. Additionally, carrying a female fetus decreases the risk of insulin resistance in the mother, from as early as the first trimester.     

Efficacy of biocides used in the modern food industry to control salmonella enterica, and links between biocide tolerance and resistance to clinically relevant antimicrobial compounds

Biocides play an essential role in limiting the spread of infectious disease. The food industry is dependent on these agents, and their increasing use is a matter for concern. Specifically, the emergence of bacteria demonstrating increased tolerance to biocides, coupled with the potential for the development of a phenotype of cross-resistance to clinically important antimicrobial compounds, needs to be assessed. In this study, we investigated the tolerance of a collection of susceptible and multidrug-resistant (MDR) Salmonella enterica strains to a panel of seven commercially available food-grade biocide formulations. We explored their abilities to adapt to these formulations and their active biocidal agents, i.e., triclosan, chlorhexidine, hydrogen peroxide, and benzalkonium chloride, after sequential rounds of in vitro selection. Finally, cross-tolerance of different categories of biocidal formulations, their active agents, and the potential for coselection of resistance to clinically important antibiotics were investigated. Six of seven food-grade biocide formulations were bactericidal at their recommended working concentrations. All showed a reduced activity against both surface-dried and biofilm cultures. A stable phenotype of tolerance to biocide formulations could not be selected. Upon exposure of Salmonella strains to an active biocidal compound, a high-level of tolerance was selected for a number of Salmonella serotypes. No cross-tolerance to the different biocidal agents or food-grade biocide formulations was observed. Most tolerant isolates displayed changes in their patterns of susceptibility to antimicrobial compounds. Food industry biocides are effective against planktonic Salmonella. When exposed to sublethal concentrations of individual active biocidal agents, tolerant isolates may emerge. This emergence was associated with changes in antimicrobial susceptibilities.     

Extensive hybridization reveals multiple coloration genes underlying a complex plumage phenotype

Coloration is an important target of both natural and sexual selection. Discovering the genetic basis of colour differences can help us to understand how this visually striking phenotype evolves. Hybridizing taxa with both clear colour differences and shallow genomic divergences are unusually tractable for associating coloration phenotypes with their causal genotypes. Here, we leverage the extensive admixture between two common North American woodpeckers—yellow-shafted and red-shafted flickers—to identify the genomic bases of six distinct plumage patches involving both melanin and carotenoid pigments. Comparisons between flickers across approximately 7.25 million genome-wide SNPs show that these two forms differ at only a small proportion of the genome (mean F_ST = 0.008). Within the few highly differentiated genomic regions, we identify 368 SNPs significantly associated with four of the six plumage patches. These SNPs are linked to multiple genes known to be involved in melanin and carotenoid pigmentation. For example, a gene (CYP2J19) known to cause yellow to red colour transitions in other birds is strongly associated with the yellow versus red differences in the wing and tail feathers of these flickers. Additionally, our analyses suggest novel links between known melanin genes and carotenoid coloration. Our finding of patch-specific control of plumage coloration adds to the growing body of literature suggesting colour diversity in animals could be created through selection acting on novel combinations of coloration genes.     

Measurement of cerebral blood volume using near-infrared spectroscopy and indocyanine green elimination.

Methods for measuring cerebral blood volume (CBV) have traditionally used radioisotopes. More recently, near-infrared spectroscopy (NIRS) has been used to measure CBV by using a technique involving O(2) desaturation of cerebral tissue, where the observed change in the concentration of oxygenated hemoglobin is a marker of the volume of blood contained within the brain. A new integration method employing NIRS is described by using indocyanine green (ICG) as the intravascular marker. After bolus injection, concentration-time integrals of cerebral tissue ICG concentration ([ICG](tissue)) measured by NIRS are compared with corresponding integrals of the cerebral blood ICG concentrations ([ICG](blood)) estimated by high-performance liquid chromatography of peripheral blood samples with allowance for cerebral-to-large-vessel hematocrit ratio. It is shown that CBV = integral [ICG]tissue/[ICG]blood. Measurements in 10 adult volunteers gave a mean value of 1.1 +/- 0.39 (SD) ml/100 g illuminated tissue. This result, although lower than previous NIRS estimations, is consistent with the long extracerebral path of light in the adult head. Scaling of results is required to take into account this component of the optical pathlength.     

Protein kinase inhibitor-(6-22)-amide peptide analogs with standard and nonstandard amino acid substitutions for phenylalanine 10. Inhibition of cAMP-dependent protein kinase

The minimal structure in the heat-stable inhibitor protein of cAMP-dependent protein kinase required for a low nanomolar potency of inhibition is the peptide Thr6-Tyr-Ala-Asp-Phe-Ile-Ala-Ser-Gly-Arg-Thr-Gly-Arg-Arg-Asn-Ala-+ ++Ile22-NH2 (PKI-(6-22)-amide). While primary structural determinants for interaction with the protein kinase are distributed throughout the 17 residues of this peptide, we have previously shown that phenylalanine 10 in the NH2-terminal portion is a particularly important determinant for high affinity binding (Glass, D. B., Cheng, H.-C., Mende-Mueller, L., Reed, J., and Walsh, D. A. (1989) J. Biol. Chem. 264, 8802-8810). To investigate this requirement further, peptide analogs of PKI-(6-22)-amide in which various natural and nonstandard amino acids are substituted for phenylalanine 10 have been synthesized and tested for inhibitory potency against the catalytic subunit of the protein kinase. Consistent with the importance of the hydrophobicity of phenylalanine, an alanine 10 substitution analog exhibited a 270-fold decrease in inhibitory potency, whereas the leucine 10 analog lost only 33-fold in activity as compared to the parent peptide PKI-(6-22)-amide. Peptides containing the spatial conformation analogs D-phenylalanine, homophenylalanine, or phenylglycine were 60-120-fold less potent than the parent peptide. Peptides containing various para-substituted phenylalanines at position 10 were only 5-11-fold less potent. One exception to this was (4'-azidophenylalanine 10)PKI-(6-22)-amide, which was nearly equipotent with the parent inhibitor. The most potent analogs were those peptides containing highly aromatic residues at position 10. The 2'-thienylalanine 10, tryptophan (formyl) 10, tryptophan 10, and the 1'-naphthylalanine 10 analogs were 3-fold less potent, equipotent, slightly more potent, and 4-fold more potent than the parent peptide inhibitor, respectively. We conclude that phenylalanine 10 in PKI-(6-22)-amide, and presumably in the native protein inhibitor, interacts through specific hydrophobic and/or aromatic binding to a hydrophobic pocket or cleft near the active site of the protein kinase.     

Task-specific impairments and enhancements induced by magnetic stimulation of human visual area V5.

Transcranial magnetic stimulation (TMS) can be used to simulate the effects of highly circumscribed brain damage permanently present in some neuropsychological patients, by reversibly disrupting the normal functioning of the cortical area to which it is applied. By using TMS we attempted to recreate deficits similar to those reported in a motion-blind patient and to assess the specificity of deficits when TMS is applied over human area V5. We used six visual search tasks and showed that subjects were impaired in a motion but not a form ''pop-out'' task when TMS was applied over V5. When motion was present, but irrelevant, or when attention to colour and form were required, TMS applied to V5 enhanced performance. When attention to motion was required in a motion-form conjunction search task, irrespective of whether the target was moving or stationary, TMS disrupted performance. These data suggest that attention to different visual attributes involves mutual inhibition between different extrastriate visual areas.     

High and intermediate affinity calmodulin binding domains of the alpha and beta subunits of phosphorylase kinase and their potential role in phosphorylation-dependent activation of the holoenzyme.

Phosphorylase kinase is a calcium-regulated multimeric enzyme of composition (alpha beta gamma delta)4, which contains calmodulin as the integral delta subunit and also is activated further by addition of extrinsic calmodulin. Previous studies by Dasgupta, M., Honeycutt, T., and Blumenthal, D.K. ((1989) J. Biol. Chem. 264, 17156-17163) have identified gamma 302-326 and gamma 342-366 as two calmodulin binding regions. Using peptides that were synthesized based on alpha and beta primary structure and that were predicted to contain the basic amphiphilic alpha-helix motif thought important for calmodulin binding, four additional potential calmodulin binding domains have now been identified: one of high affinity, beta 770-794; two of intermediate affinity, beta 5-28 and beta 920-946; and one with marginally low affinity, alpha 1070-1093. Peptide beta 770-794 was of higher calmodulin affinity than either gamma 302-326 or gamma 342-366; it was of higher affinity than the model synthetic peptide IV defined by O'Neil, K.T., and DeGrado, W.F. ((1990) Trends Biochem. Sci. 15, 59-64); and it is currently the most potent calmodulin-binding peptide so far described. Correlated with their affinity for calmodulin, all six phosphorylase kinase-derived peptides and several other established calmodulin-binding peptides inhibited phosphorylase kinase previously activated by cAMP-dependent phosphorylation, reducing its activity to the level of the nonactivated enzyme. However, these peptides did not inhibit (and some peptides slightly activated) the nonphosphorylated enzyme. Even in the presence of these peptides both activated and nonactivated enzyme remained fully Ca(2+)-dependent. The beta 770-794 peptide has at least a 5-fold greater calmodulin binding affinity than the holo-phosphorylase kinase. This, and its higher affinity for calmodulin than either of the sites on the gamma subunit, raises the possibility that in the native enzyme it may be involved in binding the intrinsic delta subunit. Further, inhibition of activated but not nonactivated enzyme by calmodulin-binding peptides would suggest that the phosphorylation-dependent activation of phosphorylase kinase may be mediated by changes in the binding interactions of the intrinsic calmodulin delta subunit.     

Monoclonal antibodies to respiratory syncytial virus proteins: identification of the fusion protein.

Six monoclonal antibodies directed against respiratory syncytial virus proteins were produced. Each was characterized by immunoprecipitation and indirect immunofluorescence. One was directed against the nucleocapsid protein. NP 44, two were directed against a 37,000-dalton protein, two were directed against the major envelope glycoprotein, GP 90, and one was directed against the 70,000-dalton envelope protein, VP 70. Indirect immunofluorescence stain patterns of infected HEp-2 cells defined GP 90 and VP 70 as viral proteins expressed on the cell surface, whereas NP 44 and the 37,000-dalton protein were detected as intracytoplasmic inclusions. One of the anti-GP 90 antibodies neutralized virus only in the presence of complement but did not inhibit cell-cell fusion. The anti-VP 70 antibody neutralized virus without complement and inhibited cell-cell fusion of previously infected HEp-2 cells, thus identifying VP 70 as the fusion protein.     

Sustained Expression of Human Cytomegalovirus Glycoprotein B (UL55) in the Seeds of Homozygous Rice Plants

Production of recombinant subunit vaccines in transgenic plants may be a means of reducing vaccine costs while increasing availability and safety. A plant-derived product found safe and effective for oral administration would provide additional advantages when used as a vaccine. Outstanding issues with the technology include transgene stability through successive generations and consistent bioproduction. We previously reported expression of glycoprotein B (gB) of human cytomegalovirus in seeds of transgenic tobacco. Here the goal was to determine if gB could be similarly expressed in rice, and if so, to examine expression over several plant generations. Results show that immunoreactive gB was successfully expressed in transgenic rice seeds, with sustained expression over three generations. The gB contained several neutralizing epitopes and was stable over 27 months.