RESUMEN
The aim of this study was to investigate the effect of Roux-en-Y gastric bypass (RYGB) on the peripheral blood microRNAs (miRNAs) of patients with type 2 diabetes mellitus (T2DM). miRNAs are small 20- to 22-nucleotide (nt) noncoding RNAs. They constitute a novel class of gene regulators that negatively regulate gene expression at the post-transcriptional level. miRNAs play an important role in several biological processes. Twelve patients with T2DM who were scheduled to undergo laparoscopic RYGB surgery were separated into two groups, using a body mass index of 30 kg/m2 as a cut-off point. Venous blood was collected before operation and 12 months after operation. A significant change was observed in the peripheral blood miRNA expression profile of both groups after RYGB surgery compared with those before operation. The expression levels of hsa-miR-29a-3p, hsa-miR-122-5p, hsa-miR-124-3p, and hsa-miR-320a were downregulated. The methylation state of the CpG sites within an approximately 400-bp genomic DNA fragment of each of the four miRNA genes, including about 200 bp upstream and 100 bp downstream of the pre-miRNA, did not vary after RYGB surgery. With remission of T2DM in both groups, RYGB could modulate the expression level of many peripheral blood miRNAs associated with lipid metabolism, insulin secretion, beta-cell function, and insulin resistance. The expression level of peripheral blood diabetes-related miRNA varied in patients with T2DM after receiving RYGB surgery, laying a strong foundation for future studies on this subject. The molecular mechanisms underlying RYGB surgery that can cause aberrant expression of miRNA remains to be determined.
Asunto(s)
Humanos , Adulto , Diabetes Mellitus Tipo 2/sangre , MicroARNs/sangre , Obesidad Mórbida/cirugía , Diabetes Mellitus Tipo 2/complicaciones , Metilación de ADN , Derivación Gástrica , Obesidad Mórbida/sangre , Obesidad Mórbida/complicaciones , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Human cytomegalovirus (HCMV) genetic determinants of endothelial cell tropism, leukocytes and dendritic cells have been identified in the genes UL131A, UL130, and UL128. We examined the structure of these three genes in HCMV. Eighteen low-passage clinical isolates and five non-passage strains from congenitally HCMV-infected infants in China were used to assess the structures of the UL131A, UL130, and UL128 genes and to find possible relationships between sequence polymorphism and different signs of HCMV disease. Comparisons were made between the UL131A, UL130, and UL128 genes of clinical strains and published sequences of Towne and Merlin strains. The UL131A coding region in the clinical strains was similar to that of Towne and Merlin strains, while UL130, and UL128 coding regions in the clinical strains were parallel with those of Towne and Merlin, respectively. Sequence comparison indicated that the UL130, and UL128 genes encode chemokine-like proteins in the clinical strain; the transmembrane regions of UL131A, and UL130 were conserved in all clinical and reference strains. The three genes of clinical strains from infants with different signs of HCMV disease had similar structure characterization. We conclude that the UL131A, UL130, and UL128 genes are highly conserved in these clinical strains. No correlation was found between the structure of the three genes and variations in HCMV disease. The finding of chemokine-like domains in UL130, and UL128 putative proteins suggests that the predicted products play a role in HCMV infectivity.
Asunto(s)
Infecciones por Citomegalovirus/genética , Infecciones por Citomegalovirus/virología , Citomegalovirus/genética , Glicoproteínas de Membrana/genética , Proteínas del Envoltorio Viral/genética , Proteínas Virales/genética , Secuencia de Aminoácidos , Secuencia de Bases , China , Secuencia Conservada , Infecciones por Citomegalovirus/epidemiología , Humanos , Lactante , Modelos Genéticos , Datos de Secuencia Molecular , Estructura Terciaria de Proteína , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido NucleicoRESUMEN
The electronic structure of Sr2RuO4 is investigated by high angular resolution ARPES at several incident photon energies. We address the controversial issues of the Fermi surface (FS) topology and the van Hove singularity at the M point, showing that a surface state and the replica of the primary FS due to sqrt[2]xsqrt[2] surface reconstruction are responsible for previous conflicting interpretations. The FS thus determined by ARPES is consistent with the de Haas-van Alphen results, and it provides additional information on the detailed shape of the alpha, beta, and gamma sheets.
RESUMEN
We report measurements of the magnetic penetration depth in single crystals of Sr2RuO4 down to 0.04 K using a tunnel-diode based, self-inductive technique. We observe a power law temperature dependence below 0.8 K, with no sign of a second phase transition nor of a crossover predicted for a multiband superconductor. A power law dependence suggests that the gap function has nodes, inconsistent with candidate p-wave states. We argue that nonlocal effects, rather than impurity scattering, can explain the observed T2 dependence instead of the T-linear behavior expected for line nodes.
RESUMEN
We have observed cyclotron resonance in the layered perovskite superconductor Sr2RuO4. We obtain cyclotron masses for the alpha, beta, and gamma Fermi surfaces of (4.33+/-0.05)m(e), (5.81+/-0. 05)m(e), and (9.71+/-0.2)m(e), respectively. The appreciable differences between these results and those obtained from de Haas-van Alphen measurements are attributable to strong electron-electron interactions in this system. Our findings appear to be consistent with predictions for an interacting Fermi liquid; indeed, semiquantitative agreement is obtained for the electron pockets beta and gamma.
RESUMEN
We investigated the behavior of the spin-triplet superconductor Sr2RuO4 ( T(c) approximately 1.5 K) under the magnetic fields parallel to the quasi-two-dimensional plane. The upper critical field H(c2) exhibits a clear fourfold anisotropy of about 3% at 0.35 K. Furthermore, we detected an additional transition feature below H(c2) in both the ac susceptibility and the specific heat. These second-transition features as well as the pronounced in-plane H(c2) anisotropy disappear above 0.8 K or under intentional field misalignment of less than 1 degrees. Most of these characteristics are consistent with the predicted emergence of the second superconducting phase with a line-node gap.
RESUMEN
We have investigated a gap structure in the spin-triplet superconductor Sr2RuO4 through the measurement of the 101Ru nuclear spin-lattice relaxation rate (101)(1/T1) down to 0.09 K at zero magnetic field. In the superconducting state, 1/T1 in a high-quality sample with T(c) approximately 1.5 K exhibits a sharp decrease without the coherence peak, followed by a T3 behavior down to 0.15 K. This result is in marked contrast to the behavior observed below approximately 0.4 K in samples with lower T(c), where T1T is a constant. This behavior is demonstrated to be not intrinsic. We conclude that the gap structure in Sr2RuO4 is significantly anisotropic, consistent with line-node-like models.
