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Zhanjiang, China

Guangdong Medical College is a medical school in Guangdong province, China. Wikipedia.


Liu G.,Guangdong Medical College | Cheresh P.,Northwestern University | Kamp D.W.,Northwestern University
Annual Review of Pathology: Mechanisms of Disease | Year: 2013

Asbestos causes asbestosis and malignancies by molecular mechanisms that are not fully understood. The modes of action underlying asbestosis, lung cancer, and mesothelioma appear to differ depending on the fiber type, lung clearance, and genetics. After reviewing the key pathologic changes following asbestos exposure, we examine recently identified pathogenic pathways, with a focus on oxidative stress. Alveolar epithelial cell apoptosis, which is an important early event in asbestosis, is mediated by mitochondria- and p53-regulated death pathways and may be modulated by the endoplasmic reticulum. We review mitochondrial DNA (mtDNA)-damage and -repair mechanisms, focusing on 8-oxoguanine DNA glycosylase, as well as cross talk between reactive oxygen species production, mtDNA damage, p53, OGG1, and mitochondrial aconitase. These new insights into the molecular basis of asbestos-induced lung diseases may foster the development of novel therapeutic targets for managing degenerative diseases (e.g., asbestosis and idiopathic pulmonary fibrosis), tumors, and aging, for which effective management is lacking. © 2013 by Annual Reviews. All rights reserved. Source


Liu X.,Guangdong Medical College
International journal of nanomedicine | Year: 2011

The purpose of this study was to develop a transdermal ligustrazine patch containing a stable formulation and with good entrapment efficiency, release rate, and transdermal absorption. Ligustrazine ethosomes were prepared by ethanol injection-sonication, with entrapment efficiency as an indicator. Using acrylic resin as the primary constituent, the ligustrazine ethosome patch was prepared by adding succinic acid as a crosslinking agent and triethyl citrate as a plasticizer. In vitro release and transdermal permeation studies were carried out. Finally, a pharmacokinetic study was carried out in rats to explore relative bioavailability. The formulations of ligustrazine ethosome were 1% (w/v) phospholipid, 0.4% (w/v) cholesterol, and 45% (v/v) ethanol. Ligustrazine ethosomes were obtained with an average particle size of 78.71 ± 1.23 nm and an average entrapment efficiency of 86.42% ± 1.50%. In vitro transdermal testing of the ligustrazine ethosome patches showed that the cumulative 24-hour amount of ligustrazine was up to 183 ± 18 μg/cm(2). The pharmacokinetic results revealed that the relative bioavailability was 209.45%. Compared with conventional ligustrazine administration, ligustrazine ethosome patches could promote better drug absorption and increase bioavailability. This study demonstrates that the transdermal action of the ligustrazine ethosome patch was comparatively good. Source


Schreiber K.H.,Buck Institute for Research on Aging | Kennedy B.K.,Buck Institute for Research on Aging | Kennedy B.K.,Guangdong Medical College
Cell | Year: 2013

Mutations in nuclear lamins or other proteins of the nuclear envelope are the root cause of a group of phenotypically diverse genetic disorders known as laminopathies, which have symptoms that range from muscular dystrophy to neuropathy to premature aging syndromes. Although precise disease mechanisms remain unclear, there has been substantial progress in our understanding of not only laminopathies, but also the biological roles of nuclear structure. Nuclear envelope dysfunction is associated with altered nuclear activity, impaired structural dynamics, and aberrant cell signaling. Building on these findings, small molecules are being discovered that may become effective therapeutic agents. © 2013 Elsevier Inc. Source


Vijg J.,Yeshiva University | Suh Y.,Yeshiva University | Suh Y.,Guangdong Medical College
Annual Review of Physiology | Year: 2013

Genome instability has long been implicated as the main causal factor in aging. Somatic cells are continuously exposed to various sources of DNA damage, from reactive oxygen species to UV radiation to environmental mutagens. To cope with the tens of thousands of chemical lesions introduced into the genome of a typical cell each day, a complex network of genome maintenance systems acts to remove damage and restore the correct base pair sequence. Occasionally, however, repair is erroneous, and such errors, as well as the occasional failure to correctly replicate the genome during cell division, are the basis for mutations and epimutations. There is now ample evidence that mutations accumulate in various organs and tissues of higher animals, including humans, mice, and flies. What is not known, however, is whether the frequency of these random changes is sufficient to cause the phenotypic effects generally associated with aging. The exception is cancer, an age-related disease caused by the accumulation of mutations and epimutations. Here, we first review current concepts regarding the relationship between DNA damage, repair, and mutation, as well as the data regarding genome alterations as a function of age. We then describe a model for how randomly induced DNA sequence and epigenomic variants in the somatic genomes of animals can result in functional decline and disease in old age. Finally, we discuss the genetics of genome instability in relation to longevity to address the importance of alterations in the somatic genome as a causal factor in aging and to underscore the opportunities provided by genetic approaches to develop interventions that attenuate genome instability, reduce disease risk, and increase life span. Copyright © 2013 by Annual Reviews. All rights reserved. Source


Liu X.,Guangdong Medical College
International journal of nanomedicine | Year: 2011

The objective of this study was to investigate the pharmacokinetics of the ligustrazine ethosome patch and antimyocardial ischemia and anti-ischemic reperfusion injury effect. Male Sprague Dawley rats were divided randomly into 3 groups: Group A (intragastric ligustrazine), Group B (transdermal ligustrazine ethosome patch), and Group C (conventional transdermal ligustrazine patch). After treatment, samples of blood and of various tissues such as heart, liver, spleen, lung, kidney, brain, and muscle samples were taken at different time points. Drug concentration was measured with HPLC, and the drug concentration-time curve was plotted. Pharmacokinetic software 3p97 was applied to calculate pharmacokinetic parameters and the area under the drug concentration-time curve (AUC) in various tissues. The rat model of acute myocardial ischemia was constructed with intravenous injection of pituitrin and the model of myocardial ischemia-perfusion injury was constructed by tying off the left anterior descending coronary artery of rats to observe the effect of ligustrazine ethosome patches on ischemic myocardium and ischemia-reperfusion injury. Results showed that AUC was highest in the transdermal drug delivery group of ligustrazine ethosome patch. There were significant differences in whole blood viscosity, plasma viscosity, hematocrit, red blood cell aggregation index, and deformation index between ligustrazine the ethosome patch group and ischemic control group (P < 0.01). Moreover, ligustrazine ethosome patches could reduce the scope of myocardial infarction induced by long-term ischemia. Ligustrazine ethosome patches have a sustained-release property. They can maintain stable and sustained blood drug concentration, increase bioavailability, and reduce administration times. The drug patch can decrease hemorheological indices of myocardial ischemia in rats, as well as protect acute ischemic myocardium and ischemia-reperfusion injured myocardium. Source

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