Effect of Sibutramine on Weight Loss and Blood Pressure: A Meta‐analysis of Controlled Trials

Objective: Sibutramine causes weight loss by suppressing the appetite and by promoting energy expenditure, but it can also increase blood pressure through a norepinephrine effect. The aim of this study was to provide a comprehensive meta‐analysis of randomized, controlled trials on the effects of sibutramine on blood pressure and weight loss. Research Methods and Procedures: Twenty‐one placebo‐controlled, double‐blind, randomized trials of sibutramine were identified using MEDLINE, EMBASE, and a manual search. The effect sizes of sibutramine on weight and systolic (SBP) and diastolic (DBP) blood pressure changes were estimated. Subgroup analyses were undertaken to explore the relationship between effect sizes and the study characteristics. Results: The effect size of sibutramine on weight change was ?1.00 (?1.17 to ?0.84), whereas the effect sizes on SBP and DBP changes were 0.16 (0.08 to 0.24) and 0.26 (0.18 to 0.33), respectively. By subgroup analysis, the effect sizes on weight loss were significantly larger when the dosage was ≥15 mg. The effect sizes on increased SBP were significantly larger when the initial body weight was ≥92 kg and the age was <44 years; similarly, the effect sizes on increased DBP were significantly larger when the initial weight was ≥92 kg. Discussion: Sibutramine showed a large effect on weight loss. Because blood pressure was found to be increased slightly, but significantly, sibutramine should be used cautiously in patients with borderline or high blood pressure. Additional studies on its effect on blood pressure are needed.     

Evidence that TGFA influences risk to cleft lip with/without cleft palate through unconventional genetic mechanisms

This study examined the association between markers in transforming growth factor alpha (TGFA) and isolated, non-syndromic cleft lip with/without palate (CL/P) using a case–parent trio design, considering parent-of-origin effects. We also tested for gene–environmental interaction with common maternal exposures, and for gene–gene interaction using markers in TGFA and another recognized causal gene, IRF6. CL/P case–parent trios from four populations (76 from Maryland, 146 from Taiwan, 35 from Singapore, and 40 from Korea) were genotyped for 17 single nucleotide polymorphisms (SNPs) in TGFA. The transmission disequilibrium test was used to test individual SNPs, and the parent-of-origin likelihood ratio test (PO-LRT) was used to assess parent-of-origin effects. We also screened for possible gene–environment interaction using PBAT, and tested for gene–gene interaction using conditional logistic regression models. When all trios were combined, four SNPs showed significant excess maternal transmission, two of which gave significant PO-LRT values [rs3821261: P = 0.004 and OR(imprinting) = 4.17; and rs3771475: P = 0.027 and OR(imprinting) = 2.44]. Haplotype analysis of these two SNPS also supported excess maternal transmission. We saw intriguing but suggestive evidence of G × E interaction for several SNPs in TGFA when either individual SNPs or haplotypes of adjacent SNPs were considered. Thus, TGFA appears to influence risk of CL/P through unconventional means with an apparent parent-of-origin effect (excess maternal transmission) and possible interaction with maternal exposures.     

Obesity and genetics regulate microRNAs in islets, liver, and adipose of diabetic mice

Type 2 diabetes results from severe insulin resistance coupled with a failure of β cells to compensate by secreting sufficient insulin. Multiple genetic loci are involved in the development of diabetes, although the effect of each gene on diabetes susceptibility is thought to be small. MicroRNAs (miRNAs) are noncoding 19–22-nucleotide RNA molecules that potentially regulate the expression of thousands of genes. To understand the relationship between miRNA regulation and obesity-induced diabetes, we quantitatively profiled approximately 220 miRNAs in pancreatic islets, adipose tissue, and liver from diabetes-resistant (B6) and diabetes-susceptible (BTBR) mice. More than half of the miRNAs profiled were expressed in all three tissues, with many miRNAs in each tissue showing significant changes in response to genetic obesity. Furthermore, several miRNAs in each tissue were differentially responsive to obesity in B6 versus BTBR mice, suggesting that they may be involved in the pathogenesis of diabetes. In liver there were approximately 40 miRNAs that were downregulated in response to obesity in B6 but not BTBR mice, indicating that genetic differences between the mouse strains play a critical role in miRNA regulation. In order to elucidate the genetic architecture of hepatic miRNA expression, we measured the expression of miRNAs in genetically obese F2 mice. Approximately 10% of the miRNAs measured showed significant linkage (miR-eQTLs), identifying loci that control miRNA abundance. Understanding the influence that obesity and genetics exert on the regulation of miRNA expression will reveal the role miRNAs play in the context of obesity-induced type 2 diabetes.     

ITS2 ribosomal DNA sequence variation of the bumblebee,Bombus ardens (hymenoptera: Apidae)

The bumblebee species,Bombus, is an invaluable natural resource for greenhouse pollination. Low levels of genetic variation ofBombus ardens have been reported in a previous mitochondrial (mt) gene study. In this study, we sequenced the complete internal transcribed spacer 2 (ITS2) of the nuclear rDNA obtained from 100B. ardens individuals collected from several Korean localities, in an effort to assess its usefulness in characterizing the genetic diversity and relationships among populations of B. ardens. The ITS2 sequences ofB. ardens were shown to be longest among known insects, ranging in size from 1,971–1,984 bp. The sequences harbor four duplicated repeats-≈27 bp repeats, ≈20 bp repeats, ≈33 bp repeats, and ≈34 bp repeats-which have never before been reported in other insect ITS2 rDNA. The maximum sequence divergence of 1.01% among 96 sequence types confirmed the applicability of this molecule to the study of intraspecific variation, revealing higher sequence variation as compared to the previously studied mt COI gene. Overall, a very high per generation migration ratio (Nm = 5.83 ≈ infinite) and a very low level of genetic fixation (FST =0 –0.08) were noted to exist among populations ofB. ardens. The high estimation of gene flow among most populations-in particular, between the remote island Ulleungdo and several inland populations-suggest that historical events may be more responsible for the contemporary population structure of B. ardens. The finding of the lowest genetic diversity (π) in the population on Ulleungdo Island (π = 0.007434) may be reflective of a relatively small population size and the geographical isolation of the population as compared with other inland populations.     

Experimental autoimmune encephalomyelitis: Association with mutual regulation of RelA (p65)/NF-κB and phospho-IκB in the CNS

Recently emerging evidence that the NF-κB family plays an important role in autoimmune disease has produced very broad and sometimes paradoxical conclusions. In the present study, we elucidated that the activation of RelA (p65) of NF-κB and IκB dissociation assumes a distinct role in experimental autoimmune encephalomyelitis (EAE) progression by altering IκB phosphorylation and/or degradation. In the present study of factors that govern EAE, the presence and immunoreactivity of nuclear RelA and phospho-IκB were recorded at the initiation and peak stage, and degradation of IκBα progressed rapidly at an early stage then stabilized during recovery. The immunoreactivity to RelA and phospho-IκB occurred mainly in inflammatory cells and microglial cells but only slightly in astrocytes. Subsequently, the blockade of IκB dissociation from NF-κB reduced the severity of disease by decreasing antigen-specific T cell response and production of IL-17 in EAE. Thus, blocking the dissociation of IκB from NF-κB can be utilized as a strategy to inhibit the NF-κB signal pathway thereby to reduce the initiation, progression, and severity of EAE.     

Glucose deprivation is associated with Chk1 degradation through the ubiquitin-proteasome pathway and effective checkpoint response to replication blocks

Chk1 plays a key role in the DNA replication checkpoint and in preserving genomic integrity. Previous studies have shown that reduced Chk1 function leads to defects in the checkpoint response and is closely associated with tumorigenesis. Here, we report that glucose deprivation caused the degradation of Chk1 protein without perturbing cell cycle progression. The induction of Chk1 degradation in response to glucose deprivation was observed in various cancer cell lines and in normal human fibroblasts. Therefore, it appears to be a universal phenomenon in mammalian cells. A specific proteasome inhibitor blocked glucose deprivation-induced Chk1 degradation. Ubiquitination of Chk1 was detected, indicating that the proteasome-ubiquitin pathway mediates Chk1 degradation upon glucose deprivation. Mechanistic studies have demonstrated that ATR-dependent phosphorylation of Chk1 at the Ser317 and Ser345 sites is not required, suggesting that the molecular mechanism for Chk1 degradation upon glucose deprivation is distinct from genotoxic stress-induced degradation. Under conditions of glucose deprivation, the cells manifested a defective checkpoint response to replication stress, camptothecin or hydroxyurea. The forced expression of Myc-Chk1 partially rescued the defective response to the replication block upon glucose deprivation. Taken together, our results indicate that glucose deprivation induces ubiquitin-mediated Chk1 degradation and defective checkpoint responses, implying its potential role in genomic instability and tumor development.     

Complete mitochondrial genome sequence of Pyropia yezoensis (Bangiales,Rhodophyta) from Korea

Species of the genera Porphyra and Pyropia are the major seaweed cultivars in Korea, Japan, and China. Genomic data from Porphyra/Pyropia species is now being used for molecular breeding and bioengineering. We determined the complete mitochondrial genome (mtDNA) sequence of Pyropia yezoensis (Bangiales, Rhodophyta) from Korea. Pyropia yezoensis mtDNA was 35,596 bp in size and exhibited high sequence similarity to Py. yezoensis mtDNA reported from China (NC_017837; 41,688 bp). However, the Korean Py. yezoensis differed from the Chinese strain in the presence/absence of introns and intronic open reading frames of the ribosomal RNA large subunit gene (rnl) and cytochrome c oxidase subunit 1 gene (cox1). These differences result in large variations between the mtDNA of the two strains of Py. yezoensis. Moreover, the Korean strain had a single copy of the trnfM–trnQ region, as compared to a duplicate copy of Py. yezoensis (NC_017837). Pyropia mtDNA exhibited unique genetic features at the intra- and interspecies levels. Therefore, mtDNA genomics can provide novel knowledge for red algal molecular systematics and help to differentiate between cultivars of Pyropia species with new molecular markers.     

Constitutive expression of abiotic stress-inducible hot pepper CaXTH3, which encodes a xyloglucan endotransglucosylase/hydrolase homolog, improves drought and salt tolerance in transgenic Arabidopsis plants

Xyloglucan endotransglucosylase/hydrolase (XTH) has been recognized as a cell wall-modifying enzyme, participating in the diverse physiological roles. From water-stressed hot pepper plants, we isolated three different cDNA clones (pCaXTH1, pCaXTH2, and pCaXTH3) that encode XTH homologs. RT-PCR analysis showed that three CaXTH mRNAs were concomitantly induced by a broad spectrum of abiotic stresses, including drought, high salinity and cold temperature, and in response to stress hormone ethylene, suggesting their role in the early events in the abiotic-related defense response. Transgenic Arabidopsis plants that constitutively expressed the CaXTH3 gene under the control of the CaMV 35S promoter exhibited abnormal leaf morphology; the transgenic leaves showed variable degrees of twisting and bending along the edges, resulting in a severely wrinkled leaf shape. Microscopic analysis showed that 35S-CaXTH3 leaves had increased numbers of small-sized cells, resulting in disordered, highly populated mesophyll cells in each dorsoventral layer, and appeared to contain a limited amount of starch. In addition, the 35S-CaXTH3 transgenic plants displayed markedly improved tolerance to severe water deficit, and to lesser extent to high salinity in comparison with the wild-type plants. These results indicate that CaXTH3 is functional in heterologous Arabidopsis cells, thereby effectively altering cell growth and also the response to abiotic stresses. Although the physiological function of CaXTHs is not yet clear, there are several possibilities for their involvement in a subset of physiological responses to counteract dehydration and high salinity stresses in transgenic Arabidopsis plants.     

Genotype–phenotype correlation of Charcot-Marie-Tooth type 1E patients with <Emphasis Type="Italic">PMP22</Emphasis> mutations

Charcot-Marie-Tooth disease type 1E (CMT1E) is a demyelinating motor and sensory neuropathy with peripheral myelin protein 22 (PMP22) point mutations. The objective of this study was to identify genetic causes and determine genotype–phenotype correlation in two Korean demyelinating CMT patients based on whole exome sequencing (WES), histological examination of distal sural nerve, and magnetic resonance imaging (MRI) of leg. WES revealed two de novo PMP22 mutations in the two demyelinating CMT patients, including one novel p.Leu82Pro (c.245T>A) mutation in one patient and one previously reported p.Ser72Leu (c.215C>T) mutation in the other patient. Both mutation sites were located in the well conserved second transmembrane domain. No control had the same mutations. The affected individual with the novel p.Leu82Pro mutation showed early onset, scoliosis, and sensory ataxia with ability to walk without assistance. Histopathological examination showed severe damage of myelin and axons. No compound muscle action potentials (CMAPs) were evoked in the upper or lower limb nerves. Leg MRIs revealed mild fatty infiltration of the bilateral peronei muscles consistent with clinical manifestations. The patient with the p.Ser72Leu mutation showed developmental delay in infancy. No CMAPs were elicited. However, she was also able to walk without assistance. In spite of markedly severe electrophysiological defects, leg MRIs showed almost normal findings except slight muscle atrophies of the lower legs. Both patients presented similar clinical features including no CMAPs in electrophysiological tests and mild fatty replacement in the lower leg MRI. Therefore, there was a good genotype–phenotype correlation in both cases.