Monoallelic expression of several genes has been observed in mice in which transcripts from parental homologues are distinguishable, but this phenomenon has not been demonstrated in humans. One monoallelically expressed murine gene, H19, encodes an abundant fetal RNA. We have found restriction site polymorphisms in the human H19 gene, located on chromosome 11p15, and examined the representation of these polymorphisms in cDNAs from fetal organs. Expression of H19 is largely or exclusively from a single allele; a similar analysis of the WT1 gene, on 11p13, shows biallelic expression. In the context of previous studies of 11p15 allelic losses in human embryonal tumours, our findings support the possibility of single-step inactivation of monoallelically expressed growth-regulating genes in human oncogenesis.
Background and Purpose
Recent reports have suggested that salidroside could protect cardiomyocytes from oxidative injury and stimulate glucose uptake in skeletal muscle cells by activating AMP‐activated protein kinase (AMPK). The aim of this study was to evaluate the therapeutic effects of salidroside on diabetic mice and to explore the underlying mechanisms.
Experimental Approach
The therapeutic effects of salidroside on type 2 diabetes were investigated. Increasing doses of salidroside (25, 50 and 100 mg·kg−1·day−1) were administered p.o. to db/db mice for 8 weeks. Biochemical analysis and histopathological examinations were conducted to evaluate the therapeutic effects of salidroside. Primary cultured mouse hepatocytes were used to further explore the underlying mechanisms in vitro.
Key Results
Salidroside dramatically reduced blood glucose and serum insulin levels and alleviated insulin resistance. Hypolipidaemic effects and amelioration of liver steatosis were observed after salidroside administration. In vitro, salidroside dose‐dependently induced an increase in the phosphorylations of AMPK and PI3K/Akt, as well as glycogen synthase kinase 3β (GSK3β) in hepatocytes. Furthermore, salidroside‐stimulated AMPK activation was found to suppress the expression of PEPCK and glucose‐6‐phosphatase. Salidroside‐induced AMPK activation also resulted in phosphorylation of acetyl CoA carboxylase, which can reduce lipid accumulation in peripheral tissues. In isolated mitochondria, salidroside inhibited respiratory chain complex I and disturbed oxidation/phosphorylation coupling and moderately depolarized the mitochondrial membrane potential, resulting in a transient increase in the AMP/ATP ratio.
Conclusions and Implications
Salidroside exerts an antidiabetic effect by improving the cellular metabolic flux through the activation of a mitochondria‐related AMPK/PI3K/Akt/GSK3β pathway
Nitrogen-containing bisphosphonates, drugs used to treat bone resorption diseases, also have activity against a broad range of protists, including blood-stage Plasmodium spp. Here, we show that newgeneration "lipophilic" bisphosphonates designed as anticancer agents that block protein prenylation also have potent activity against Plasmodium liver stages, with a high (>100) therapeutic index. Treatment of mice with the bisphosphonate BPH-715 and challenge with Plasmodium berghei sporozoites revealed complete protection (no blood-stage parasites after 28 days). There was also activity against blood-stage forms in vitro and a 4-day delay in the prepatent period in vivo. The lipophilic bisphosphonates have activity against a Plasmodium geranylgeranyl diphosphate synthase (GGPPS), as well as low nM activity against human farnesyl and geranylgeranyl diphosphate synthases. The most active inhibitor in vitro and in vivo had enzyme inhibitory activity similar to that of the other, less active compounds but was more lipophilic. Lipophilic bisphosphonates are thus promising leads for novel antimalarials that target liver-stage infection.
Salmonella is one of the most common foodborne pathogens in humans. Laboratory-based surveillance for non-typhoidal Salmonella infection was conducted in Guangdong Province, China to improve understanding about the disease burden and detection of dispersed outbreaks. Salmonella isolated from patients with diarrhea were sent from 16 sentinel hospitals to local public health laboratories for confirmation, serotyping, antimicrobial susceptibility testing, and pulsed-field gel electrophoresis (PFGE). PFGE patterns were analyzed to identify clusters representing potential outbreaks. Between September 2009 and October 2010, 352 (4%) Salmonella isolates were obtained from 9167 stool specimens. Salmonella enterica serotype Typhimurium (45%) and Salmonella enterica serotype Enteritidis (13%) were the most common serotypes, and multidrug resistance was high, especially in Salmonella Typhimurium isolates. PFGE patterns of obtained Salmonella isolates were found to be diverse, but a unique PFGE pattern comprising 53 Salmonella Typhimurium isolates were found to occur almost exclusively in infants. Epidemiologic studies are ongoing to determine whether a common exposure is the source of the Salmonella Typhimurium strain frequently isolated from infants.
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