Effects of Growth Hormone Treatment on Lipid Profiles

OBJECTIVES

To assess the effects of growth hormone (GH) on lipid profiles in children and whether the effect is pharmacological.

METHODS

The authors determined serum levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), and low-density lipoprotein cholesterol (LDL-C) every year during 3-y GH treatment in 48 GH deficient (GHD) short children and 22 children with short stature born small for gestational age (SGA).

RESULTS

The abnormally high levels of TC, non-HDL-C, and LDL-C showed a high frequency in GHD short children compared with epidemiological studies in Japan. The high prevalence of high level of TC was also shown in SGA short children. Three-year GH treatment decreased serum TC, non-HDL-C, and LDL-C levels in both patient groups.

CONCLUSIONS

GH treatment is clearly a pharmacological therapy in SGA short children and so may also be in GHD short children at the Japanese standard therapeutic dose. Taken together, GH improves lipid profiles, and its effect has the possibility of medical properties.

Publisher Correction: An adaptive supramolecular hydrogel comprising self-sorting double nanofibre networks

In the version of this Article originally published online, in Fig. 4b, in the lower-right image, the value of r was incorrect; it should have read 'r = 0.72'. This has now been corrected in all versions of the Article.

Viscoelasticity of dense suspensions of thermosensitive microgel mixtures undergoing colloidal gelation

Dense suspensions of temperature (T)-sensitive poly(N-isopropyl acrylamide) (N) and poly(N-isopropyl methacrylamide) (NM) microgel mixtures with different volume transition temperatures (T and T, respectively; T < T) exhibit a characteristic T-dependent viscoelasticity due to T-induced changes in the type of interparticle interaction as well as the volume fraction of each gel. In the range of T < T, where the swollen microgels with repulsive interparticle interactions are densely packed, the equilibrium modulus (G) decreases upon heating due entirely to the packing effect, i.e., a reduction in the total volume fraction of the microgels (φ). At T > T where the attractive interparticle interactions between dehydrated and hydrophobic microgels emerge, the suspensions show solid-like elastic properties due to the network-like flocculation of the shrunken microgels (colloidal gelation), even when φ becomes considerably lower than the threshold for randomly close packing. The T-dependence of G shows a minimum at a characteristic temperature (T_B; T_B > T) due to the competition between the repulsive interparticle interactions from the packing effect and electrostatic force, and the attractive interactions from the hydrophobicity. The T_B in N/NM mixture suspensions shifts to a higher value with a decrease in N content in the mixtures (X_N), accompanied by a discontinuous-like change at a specific value of X_N (X_N*). The T_B at every value of X_N agrees approximately with the temperature where the total volume fraction of the attractive hydrophobic microgels is 0.3 regardless of microgel type (N or NM). The discontinuous-like variation in T_B at X_N* reflects the change in the network-like flocculation particles, from only attractive N microgels in the high X_N regime, to the attractive N and NM microgel mixtures in the moderate X_N regime. The requirement of the repulsive electrostatic force with an appropriate strength for the stability of the network-like flocculation is also demonstrated using the PNIPAM-co-fumaric acid (NF) microgel suspensions at various pH.

An adaptive supramolecular hydrogel comprising self-sorting double nanofibre networks

Novel soft materials should comprise multiple supramolecular nanostructures whose responses (for example, assembly and disassembly) to external stimuli can be controlled independently. Such multicomponent systems are present in living cells and control the formation and break-up of a variety of supramolecular assemblies made of proteins, lipids, DNA and RNA in response to external stimuli; however, artificial counterparts are challenging to make. Here, we present a hybrid hydrogel consisting of a self-sorting double network of nanofibres in which each network responds to an applied external stimulus independent of the other. The hydrogel can be made to change its mechanical properties and rates of release of encapsulated proteins by adding Na₂S₂O₄ or bacterial alkaline phosphatase. Notably, the properties of the gel depend on the order in which the external stimuli are applied. Multicomponent hydrogels comprising orthogonal stimulus-responsive supramolecular assemblies would be suitable for designing novel adaptive materials.

Association of NOD2 Mutations with Aggressive Periodontitis

Aggressive periodontitis (AgP) is characterized by rapid alveolar bone destruction and tooth loss early in life, and its etiology remains unclear. To explore the genetic risk factors of AgP, we performed genome-wide single-nucleotide polymorphism genotyping for identity-by-descent mapping and identified 32 distinct candidate loci, followed by whole exome sequencing with 2 pedigrees of AgP consisting of 3 cases and 1 control in 1 family and 2 sibling cases in the other. After variant filtering procedures and validation by targeted Sanger sequencing, we identified 2 missense mutations at 16q12 in NOD2 (p.Ala110Thr and p.Arg311Trp), which encodes nucleotide-binding oligomerization domain protein 2. We further examined 94 genetically unrelated AgP patients by targeted sequencing of NOD2 and found that 2 patients among them also carried the p.Arg311Trp variant. Furthermore, we found 3 additional missense mutations in this gene (p.His370Tyr, p.Arg459Cys, and p.Ala868Thr). These mutations either had not been previously observed or are extremely rare (frequency <0.001) in Asian populations. NOD2 plays a crucial role in innate immunity as an intracellular receptor initiating nuclear factor κB-dependent and mitogen-activated protein kinase-dependent gene transcription. These results demonstrated NOD2 as a novel gene involved in AgP.

Thermal bending coupled with volume change in liquid crystal gels

We investigate the thermal bending behavior of liquid crystal gels with hybrid alignment (H-LCGs) accompanied by volume change in isotropic and nematic solvents. The curvature (r^-1) of H-LCGs in each solvent markedly depends on the temperature (T) in the nematic state including the reversal of the bending direction, as in the case of the corresponding elastomers in the dry state (H-LCE). The thermal bending of three systems-H-LCGs in isotropic and nematic solvents and H-LCE-differs significantly in several aspects including the T range where r^-1 depends on T and the total variation of r^-1. The differences in these features among the three systems result from the differences in the magnitude as well as the T-dependence of the nematic order (S), which is correlated with the T-induced volume change. We demonstrate that the T-dependence of the reduced curvature in each system is satisfactorily described by a combination of linear bending theory and the anisotropic Gaussian network model using the corresponding S-T data.

Novel features of the Mullins effect in filled elastomers revealed by stretching measurements in various geometries

Stretching experiments with various geometries are performed using a custom-built tensile tester to reveal the intriguing features of the mechanical softening phenomena of filled elastomers in loading-unloading cycles, commonly known as the Mullins effect. The dissipated energy (D), residual strain (ε^r), and dissipation factor (Δ; the ratio of D to input strain energy) in the loading-unloading cycles are evaluated as a function of the maximum stretch in cyclic loading (λ_m) using three types of extension, i.e., uniaxial, planar, and equibiaxial extension, for silica-filled elastomers with various filler contents, and with or without a silane coupling agent. The dissipated energy D and ε^r increase with an increase in λ_m, and they depend on the type of extension when compared at the same λ_m: D and ε^r increase in the order of equibiaxial, planar, and uniaxial extension. In contrast, the values of Δ obtained for various degrees and types of extension are collapsed into a single curve when the first invariant of the deformation tensor (I_1,m) corresponding to λ_m is employed as a variable: Δ steeply increases with an increase in I_1,m in the small deformation regime of I_1,m < 3.2, while Δ levels off in the large deformation regime of I_1,m > 3.5. The plateau values of Δ increase with an increase in filler content. The characteristic dependence of Δ on I_1,m in each of the small and large deformation regimes is expected to reflect the destruction process of the inherent structures, including filler networks and the filler-polymer interface, and the friction between the fillers and the rubber matrix, respectively.

Usefulness of non-fasting lipid parameters in children

BACKGROUND

This study assessed whether non-fasting lipid markers could be substituted for fasting markers in screening for dyslipidemia, whether direct measurement of non-fasting low-density lipoprotein cholesterol [LDL-C (D)] could be substituted for the calculation of fasting LDL-C [LDL-C (F)], and the utility of measuring non-high-density lipoprotein cholesterol (non-HDL-C).

METHODS

In 33 children, the lipid profile was measured in the non-fasting and fasting states within 24 h. Correlations were examined between non-fasting LDL-C (D) or non-HDL-C levels and fasting LDL-C (F) levels.

RESULTS

Non-fasting triglyceride (TG), total cholesterol (TC), HDL-C, LDL-C (D), and non-HDL-C levels were all significantly higher than the fasting levels, but the mean difference was within 10% (except for TG). Non-fasting LDL-C (D) and non-HDL-C levels were strongly correlated with the fasting LDL-C (F) levels.

CONCLUSIONS

In conclusion, except for TG, non-fasting lipid parameters are useful when screening children for dyslipidemia. Direct measurement of non-fasting LDL-C and calculation of non-fasting non-HDL-C could replace the calculation of fasting LDL-C because of convenience.

Velocity transition in the crack growth dynamics of filled elastomers: Contributions of nonlinear viscoelasticity

The crack growth dynamics of the carbon-black (CB) filled elastomers is studied experimentally and analyzed while focusing on both kinetics and crack tip profiles. The CB amounts are varied to change the mechanical properties of the elastomers. Static crack growth measurements simultaneously reveal the discontinuous-like transition of the crack growth rate v between the "slow mode" (v≈10^{-5}-10^{-3} m/s) and "fast mode" (v≈10^{-1}-10^{2} m/s) in a narrow range of the input tearing energy Γ and the accompanying changes in the crack tip profiles from blunt to sharp shapes. The crack tip profiles are characterized by two specific parameters, i.e., the deviation δ from the parabolic profile and the opening displacement a in the loading direction. The analysis based on the linear and weakly nonlinear elasticity theories of fracture dynamics demonstrates that the Γ dependence of δ and a is simply classified into three groups depending on the mode (slow or fast) and the magnitudes of δ, independent of CB volume fractions. The theories well explain the results in the slow and fast modes with small magnitudes of δ, while they fail to describe the data in the fast mode with large magnitudes of δ, where the contributions of the strong nonlinearity and/or energy dissipation become significant. The correlation between a power-law relationship Γ∼v^{α} observed in the fast mode and the linear viscoelasticity spectrum is also discussed. The correlation in elastomers with low CB volume fractions is quantitatively explained by the theory of Persson and Brener [Phys. Rev. E 71, 036123 (2005)PLEEE81539-375510.1103/PhysRevE.71.036123], whereas the deviation from the theory becomes appreciable for elastomers with higher CB volume fractions which exhibit strong nonlinear viscoelasticity.

Tunable lasing in cholesteric liquid crystal elastomers with accurate measurements of strain

We report wide range and reversible tuning of the selective reflection band of a single crystal cholesteric liquid crystal elastomer (CLCE). The tuning is the result of mechanical shortening of the helical pitch achieved by imposing a uniform uniaxial strain along the helical axis. On doping the CLCE sample with a laser dye, we observe lasing from the CLCE in both glassy and rubbery states. By changing the cholesteric pitch, mechanical compression provides tuning of the laser emission from the dye doped CLCE over a significant part of the fluorescence band of the laser dye. In this work we demonstrate for the first time that both the CLCE pitch and the lasing wavelength are linearly dependent on the strain imposed on the CLCE film.

Thermal response of cholesteric liquid crystal elastomers

The effects of temperature variation on photonic properties of cholesteric liquid crystal elastomers (CLCEs) are investigated in mechanically unconstrained and constrained geometries. In the unconstrained geometry, cooling in the cholesteric state induces both a considerable shift of the selective reflection band to shorter wavelengths and a finite degree of macroscopic expansion in the two directions normal to the axis of the helical director configuration. The thermal deformation is driven by a change in orientational order of the underlying nematic structure S and the relation between the macroscopic strain and S is explained on the basis of the anisotropic Gaussian chain network model. The helical pitch varies with the film thickness in an affine manner under temperature variation. The CLCEs under the constrained geometry where thermal deformation is strictly prohibited show no shift of the reflection bands when subjected to temperature variation. This also reveals the strong correlation between the macroscopic dimensions and the pitch of the helical director configuration.

A simple feature of yielding behavior of highly dense suspensions of soft micro-hydrogel particles

The highly dense suspensions of soft micro-hydrogels with a narrow size distribution (typically ϕeff > 0.9 where ϕeff is the apparent volume fraction of the particle), which form a regular lattice structure, exhibit a simple feature in the yielding behavior: the yield strain γc [ca. 2.5% and ca. 4.8% for poly(N-isopropylmethacrylamide) (PNIPMA) and poly(N-isopropylacrylamide) (PNIPA) hydrogel particles, respectively] is nearly insensitive to the cross-link concentration (cx), particle diameter (Dh), and particle concentration (c) in the limited c range examined here, and γc is almost constant in a wide range of equilibrium shear moduli over two orders of magnitude. In addition, no appreciable difference in γc is observed in the dense pastes with crystalline and glassy structures which are formed by mono- and bidisperse microgels, respectively. This is in contrast to a finite difference in γc for the crystal and glass formed by the hard sphere reported by Koumakis et al. [Soft Matter, 4, 2008 (2008)]. Furthermore, the highly dense suspensions of NIPA core-NIPMA shell microgels are similar in γc to those of NIPMA microgels. These results indicate that γc for the highly dense suspensions of soft micro-hydrogels depends primarily on the kind of constituent polymer near the particle surface. The yield strain γc is expected to be governed by short-range interactions such as adhesion and friction.