ABSTRACT
Methamphetamine (METH) is a powerful stimulant drug that can cause addiction and serious health problems. It is one of the most widely abused drugs in the world. However, the mechanisms of how METH affects the brain and leads to addiction are still unclear, and there are no effective treatments for METH addiction in clinical practice. Therefore, it is important to explore the new addiction mechanisms and treatment strategies of METH. METH addiction is a complex and chronic brain disorder that involves multiple brain regions and neurotransmitter systems. Neurotransmitters are chemical messengers that transmit signals between neurons (nerve cells) in the brain. Some of the main neurotransmitters involved in METH addiction are dopamine (DA), glutamate (Glu), norepinephrine (NE), and serotonin (SNRIS). These neurotransmitters regulate various aspects of brain function, such as reward, reinforcement, motivation, cognition, emotion, and behavior. When a person takes METH, it causes a surge of these neurotransmitters in the brain, especially in the prefrontal cortex (mPFC), ventral tegmental area (VTA), and nucleus accumbens (NAc). These brain regions form a circuit called the mesocorticolimbic system, which is responsible for mediating the rewarding and reinforcing effects of drugs and natural stimuli. The increased levels of neurotransmitters in this circuit make the person feel euphoric, alert, confident, and energetic. However, repeated or chronic use of METH can also cause negative effects, such as anxiety, paranoia, psychosis, depression, and cognitive impairment. The effects of METH on the brain are not only due to the changes in neurotransmitter levels, but also to the changes in gene expression. Gene expression is the process by which genes are turned on or off to produce proteins that perform various functions in the cells. Gene expression can be influenced by environmental factors, such as drugs, stress, diet, etc. One way that environmental factors can affect gene expression is through epigenetic mechanisms. Epigenetics is a branch of genetics that studies the heritable changes in gene expression that are not caused by changes in DNA sequence. Epigenetic mechanisms include histone modifications, DNA methylation, and non-coding RNA regulation. These mechanisms can modulate the chromatin structure and accessibility, thereby affecting the transcriptional activity of genes. Chromatin is a complex of DNA and proteins that forms the chromosomes in the nucleus of the cell. The chromatin structure can be altered by adding or removing chemical groups to histones (proteins that wrap around DNA) or DNA itself. These chemical groups can either activate or repress gene expression by changing the affinity of transcription factors (proteins that bind to DNA and initiate transcription) or other regulatory molecules. Non-coding RNAs are RNA molecules that do not code for proteins but can regulate gene expression by interacting with DNA, RNA, or proteins. Epigenetic mechanisms provide a link between environmental stimuli and gene expression, and play an important role in various physiological and pathological processes, including drug addiction. Recent studies have shown that epigenetic mechanisms are involved in the regulation of neurotransmitter systems and neural plasticity in response to METH exposure. Neural plasticity is the ability of neurons to change their structure and function in response to experience or injury. Neural plasticity is essential for learning, memory, adaptation, and recovery. The expression of some genes related to METH addiction is altered by epigenetic modifications, such as histone acetylation, methylation, ubiquitination, and non-coding RNA regulation. These epigenetic changes may affect the synaptic function and morphology, neuronal connectivity, and circuitry formation in the brain regions implicated in METH addiction. Moreover, some epigenetic modifications may persist for a long time after METH withdrawal, suggesting that they may contribute to the development and maintenance of METH addiction. In this article, we review the current literature on the epigenetic mechanisms of METH addiction. We will first introduce METH and its pharmacological effects, and then discuss the epigenetic regulation of neurotransmitter systems and neural plasticity by METH. We will focus on the changes of histone, DNA, and RNA during METH addiction, and the possible causes and consequences of their relationship with METH addiction. We will also provide some perspectives on the potential applications of epigenetic interventions for METH addiction treatment.
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Clinical pathway is an important quality management tool for regulating medical behavior both at home and abroad, and an important means of controlling medical costs in the reform of medical insurance payment methods.The author reviewed the current development status of clinical pathways both at home and abroad, focusing on summarizing the development experience of foreign countries, and analyzing the shortcomings in the development of clinical pathways in China from the perspectives of formulation, implementation, and evaluation. It is proposed that China should establish and improve the regulatory and incentive mechanisms for clinical pathways, accelerate the construction of supporting medical security systems, explore new incentive transmission models, attach importance to the role of patient participation in the formulation and implementation of clinical pathways, and so on, in order to provide reference for promoting the efficient development of clinical pathways in China.
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Aim To establish a batch of endotoxin standard for baeterial endotoxin detection of insoluble samples.Methods Candidate A and candidate B were prepared by freeze -drying bacterial endotoxin without excipient.The two batches of candidates were calibrated by three methods, including 13 laboratories for gel method, 9 laboratories for kinetic-turbidimetric assay and 5 laboratories for kinetic chromogenic assay.Results After statistical analysis, the geometric mean values of gel method, kinetic-turbidimetric assay and kinetic chromogenic assay calibration of candidate A were 680.1 EU, 827.0 EU and 800.8 EU, with RSD of 22.4%, 16.2% and 16.7%, respectively.The P value of variance analysis of calibration results of the three methods was 0.067, showing no significant difference.The weighted mean of potency was 774.0 EU (95% confidence interval 721.0 - 831.0, FL% 7.10).The geometric mean values of the calibration of candidate B by gel method, kinetic-turbidimetric assay and kinetic chromogenic assay method were 1 640.6 EU, 1 828.6 EU and 3 224.8 EU, with RSD of 33.9% , 47.0% and 54.4% , respectively.The P val¬ue of variance analysis of the calibration results of the three methods was 0.030, showing significant differ¬ence.Chi-square test was used to correct the weight of each method , and weighted average of the results of the three methods was used to obtain a corrected weighted average efficiency value of 1 822.7 EU (95% confi¬dence interval 1 548.7 -2 145.2, FL% 16.4).Can¬didate B was eliminated based on the results.Conclu¬sion Candidate A has become the first batch of na¬tional standard bacterial endotoxin (for insoluble sam¬ples only) approved by National Standard Substance Committee of China, and the potency is 700 EU.
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Insulin is a commonly used measure of pancreatic β-cell function but exhibits a short half-life in the human body. During biosynthesis, insulin release is accompanied by C-peptide at an equimolar concentration which has a much higher plasma half-life and is therefore projected as a precise measure of β-cell activity than insulin. Despite this, genetic studies of metabolic traits haveneglected the regulatory potential of C-peptide for therapeutic intervention of type-2 diabetes. The present study is aimed to search genomewide variants governing C-peptide levels in genetically diverse and high risk population for metabolic diseases—Indians. We performed whole genome genotyping in 877 healthy Indians of Indo-European origin followed by replication of variants with P ≤ 1 × 10−3 in an independent sample-set of 1829 Indians. Lead-associated signals were also tested in-silico in 773 Hispanics. To secure biological rationale for observed association, we further carried out DNA methylation quantitative trait loci analysis in 233 Indians and publicly available regulatory data was mined. We discovered novel lncRNA gene AC073333.8 with the strongest association with C-peptide levels in Indians that however missed genomewide significance. Also, noncoding genes, RP1-209A6.1 and RPS3AP5; protein gene regulators, ZNF831 and ETS2; and solute carrier protein gene SLC15A5 retained robust association with C-peptide after meta-analysis. Integration of methylation data revealed ETS2 and ZNF831 single-nucleotide polymorphisms as significant meth-QTLs in Indians. All genes showed reasonable expression in the human lung, signifying alternate important organs for C-peptide biology. Our findings mirror polygenic nature of C-peptide where multiple small-effect size variants in the regulatory genome principally govern the trait biology.
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Objective To investigate the process of autophagy in myocardial cells induced by methamphetamine (METH).Methods In vivo study:sixty 6-week-old male C57B1/6 J mice were randomly(random number) divided into three groups evenly,control group,three-day METH treated group and seven-day METH treated group.Mice in control group was given physiological saline through intraperitoneal injection 2 times per day and lasted 7 days.Mice in three days group and seven days group intake methamphetamine at a dose of 15 mg/kg every time through intraperitoneal injection 2 times a day,lasted 3 days and 7 days respectively.The hearts of the mice were then obtained by anatomical method 24 hours after the last intraperitoneal injection of METH,then autophagy related proteins were detected by western blotting.In vitro study:the model was established by H9C2 cells.The cells were divided into two groups,control group (cells were cultured by normal medium) and METH group (cells were cultured by medium includes 900 mmol/mL METH for 24 hours).The expressions change of autophagy related proteins in cells were tested by Western blotting.Additionally,LC3-Ⅱ was tagged by red fluorescent and then the stained cells were visualized under a Zeiss LSM710 confocal microscope.Furthermore,the numbers of autophagosomes in cells were visualized by transmission electron microscopy.Results The expression of p62,Beclin-land LC3 were significantly increased in METH group when compared with control group (P＜0.05).The level of LC3 was significantly increased in METH treated group compared with control group visualized under a Zeiss LSM710 confocal microscope.The numbers of autophagosomes in METH group are more than control group visualized by transmission electron microscopy.Conclusions Autophagy can be induced by METH in myocardial cells.
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Aim To evaluate the influence of METH on MMP, mitochondrial ultrastructure, and the expression levels of mitochondrial proteins, Mfnland Fisl, in human neuroblastoma SH-SY5Y cells in vitro. Methods A stable and feasible culture method of SH-SY5Y cells in vitro was established with different concentrations of METH(0. 0, 1. 0, 1. 5 and 2. 0 mmol L-1), and for various periods of exposure for 3, 6, 12, 24 h, the MMP of SH-SY5Y cells was stained by MMP assay kit (JC-1) , the mitochondrial ultrastructure of SH-SY5Y cells exposed to METH was observed by transmission electron microscope, and the expression levels of Mfnl and Fisl proteins were detected by Western blot. Results Compared with control group for various periods of exposure(3,6,12,24 h), the red/green fluorescence ratios of MMP and the expression levels of Mfn1 protein decreased significantly in METH groups (P<0. 05) , while the expression levels of Fisl pro-tein increased significantly (P <0.05). SH-SY5Y cells were treated with METH for 24 h prior to observation under transmission electron microscope ( TEM ). The mitochondria of SH-SY5Y cells in unprocessed group showed the oval, rodlike and double-layer membrane structure, along with clear normal mitochondrial cristae. However, the oval and rodlike structure of mitochondria in SH-SY5Y cells of METH treatment groups had been split into small ball structures. Moreover , mitochondrial autophagosome and autophagic iyso-some could also be found. Conclusions METH could induce a decrease in MMP, mitochondrial ultrastruc-tural changes, and changes in the expression levels of Mfnl and Fisl in SH-SY5Y cells, which might be associated with nerve cell damage caused by METH.
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Behavioral adjustment plays an important role in the treatment and relapse of drug addiction. Nonetheless, few studies have examined behavioral adjustment and its plasticity following error commission in methamphetamine (METH) dependence, which is detrimental to human health. Thus, we investigated the behavioral adjustment performance following error commission in long-term METH addicts and how it varied with the application of repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex (DLPFC). Twenty-nine male long-term METH addicts (for > 3 years) were randomly assigned to high-frequency (10 Hz, n = 15) or sham (n = 14) rTMS of the left DLPFC during a two-choice oddball task. Twenty-six age-matched, healthy male adults participated in the two-choice oddball task pretest to establish normal performance for comparison. The results showed that 10 Hz rTMS over the left DLPFC significantly decreased the post-error slowing effect in response times of METH addicts. In addition, the 10 Hz rTMS intervention remarkably reduced the reaction times during post-error trials but not post-correct trials. While the 10 Hz rTMS group showed a more pronounced post-error slowing effect than the healthy participants during the pretest, the post-error slowing effect in the posttest of this sample was similar to that in the healthy participants. These results suggest that high-frequency rTMS over the left DLPFC is a useful protocol for the improvement of behavioral adjustment after error commission in long-term METH addicts.
Subject(s)
Adult , Humans , Male , Middle Aged , Young Adult , Adjustment Disorders , Therapeutics , Amphetamine-Related Disorders , Therapeutics , Case-Control Studies , Central Nervous System Stimulants , Choice Behavior , Physiology , Functional Laterality , Methamphetamine , Prefrontal Cortex , Physiology , Reaction Time , Physiology , Transcranial Magnetic Stimulation , MethodsABSTRACT
OBJECTIVE:To investigate the expression difference and its mechanism of miR-497 and miR-34a in platinum-sen-sitive and platinum-resistant epithelial ovarian carcinoma(EOC)patients. METHODS:A total of 72 EOC patients underwent ovari-an cancer staging surgery or cytoreductive surgery were selected from department of gynaecology and obstetriscs of our hospital dur-ing Jan. 2008-Jan. 2012. They received standardized platinum chemotherapy after surgery and were followed up (during Jul.2008-Jul.2016). According to the sensitivity to platinum,those patients were divided into platinum-sensitive group (42 cases) and platinum-resistant group (30 cases) . Real-time fluorescent quantitative PCR was adopted to detect the expression of miR-497 and miR-34a in tumor tissue,and the relationship of it with total survival period was investigated. The levels of DNA methylation of miR-497 and miR-34a promoter region were determined by nest type land type methylation specific PCR. Western blot assay was used to detect the H3K9 dimethylation(H3K9me2)levels. The H3K9me2 levels of miR-497 and miR-34a promoter region were de-termined by chromatin immunoprecipitation method. RESULTS:The expression levels of miR-497 and miR-34a in platinum-sensi-tive group were significantly higher than platinum-resistant group,with statistical significance (P0.05). CONCLUSIONS:The expression of miR-497 and miR-34a in tumor tissue of EOC patients are related to the sensitivity of platinum chemotherapy and the survival time of patients. DNA methylation and histone methylation of promoter region may be one of the mechanisms of their expression changes.
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Objective To make the chromosome karyotype analysis of 130 patients with leukemia by using the improved chromosome short-term culture method.Methods We optimized the main factors with a single factor gradient experiment in short-term culture of bone marrow chromosome, including colchicines concentration, duration of action of colchicines,and hypotonic time.On this basis,we conducted the three-factors and three-level orthogonal experiment to achieve improved bone marrow chromosome preparation system,which was later applied in 130 patients with leukemia in our hospital.Results The orthogonal experiment results showed that the optimum conditions were colchicines concentration of 0.07 μg/mL,colchicines action time of 80 min,and hypotonic time of 35 min during the preparation of the bone marrow chromosome.Using this method,the chromosome preparation success rate reached 97.69% and the detection rate of abnormal karyotype reached 82.3% in the chromosome karyotype analysis.Conclusion Bone marrow chromosome preparation system with colchicines concentration of 0.07 μg/mL and colchicines action time of 80 min,and hypotonic time of 35 min is worthy of clinical promotion.
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A dissolution method with robust high performance liquid chromatographic (HPLC) analysis for im-mediate release tablet formulation was developed and validated to meet the requirement as per Inter-national Conference on Harmonization (ICH) and United States Food and Drug Administration (USFDA) guidelines. The method involved the use of Agilent ZORBAX Eclipse XDB C18 column, and temperature was maintained at 30 °C. After optimization, the mobile phase was selected as phosphate buffer (KH2PO4, 30 mM):ACN (60:40, v/v) with pH 3.0, and retention time Rt was found as 3.24, 4.16, and 2.55 min for paracetamol (PCM), chlorpheniramine maleate (CPM) and phenylephrine hydrochloride (PH) respec-tively at 265 nm and at a flow rate of 1 mL/min. The relative standard deviation (%RSD) for 6 replicate measurements was found to be less than 2%. Furthermore net analyte signal standard addition method (NASSAM) with spectrophotometer was performed for standard and liquid oral suspension. On the basis of selectivity, sensitivity and accuracy analysis, it was confirmed that this novel method could be useful for simultaneous estimation of the given drug combinations. Two-way analysis of variance (ANOVA) was applied for evaluating the statistical difference between the assay results obtained via both NASSAM and RP-HPLC methods and ultimately no significant difference was found between both the methods. All the methods and results were acceptable and confirmed that the method was suitable for intended use.
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OBJECTIVE:To optimize the extraction technique for Sidiming capsules.METHODS:The technical conditions for the water decoction and the alcohol precipitation were optimized respectively by the orthogonal experiment design L9(34)with hydrosoluble extract used as the index for the water decoction and the catalpol extract for alcohol precipitation.The content of Catalpol was determined by HPLC.RESULTS:The optimum conditions were as follows:decocting the crude drugs twice with 8-fold water,1 h each time.The physic liquor extracted by water was filtered,mixed and concentrated to 1.0 g?mL-1(crude drug),and then precipitated by 75% concentration of alcohol for 24 h.Then the physic liquor was filtered,concentrated and dried by microwave vacuum concentration dryer to obtain the dry ointment.CONCLUSION:The optimum extraction procedure is stable and reliable,and it can be used as the optimal extraction procedure of Sidiming capsules.