Molecular Spectrum of α- and β-Thalassemia among Young Individuals of Marriageable Age in Guangdong Province, China / 生物医学与环境科学（英文）

Thalassemia is a group of genetically heterogeneous diseases characterized by hemolytic anemia. To investigate molecular characteristics of α- and β-thalassemia among young individuals of marriageable age in Guangdong Province, 24,788 subjects with suspected thalassemia were genetically tested for α- and β-thalassemia by Gap-PCR and reverse dot blot during 2018-2019. For suspected rare thalassemia cases, DNA sequencing was performed to identify rare and unknown thalassemia gene mutations. A total of 14,346 thalassemia carriers were detected, including 7,556 cases of α-thalassemia with 25 genotypes and 8 α-gene mutations identified, 5,860 cases of β-thalassemia with 18 genotypes and 18 β-gene mutations identified, and 930 cases of compound α/β-thalassemia. Among them, the frequency of --

Effectiveness of Using Mean Corpuscular Volume and Mean Corpuscular Hemoglobin for Beta-thalassemia Carrier Screening in the Guangdong Population of China / 生物医学与环境科学（英文）

Beta (β)-thalassemia is one of the most common hemoglobinopathies worldwide, creating major public health problems and social burdens in many regions. Screening for β-thalassemia carriers is crucial for controlling this condition. To investigate the effectiveness of mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) for screening β-thalassemia, retrospective data were analyzed for 6,779 β-thalassemia carriers subjected to genetic testing following thalassemia screening in Guangdong province between January 2018 and December 2019. Prevalent mutations observed included CD41/42 (-TTCT) (38.43%), IVS-II-654 (C > T) (25.71%), -28 (A > G) (15.78%), CD17 (AAG > TAG) (10.03%), and β

Chromosome abnormalities and Y chromosome microdeletions in patients with the azoospermia and cryptozoospermia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the incidence of the chromosome abnormalities and Y chromosome microdeletions in Chinese patients with azoospermia and cryptozoospermia.</p><p><b>METHODS</b>Conventional chromosomal karyotyping was used to analyze the chromosome abnormalities. Genomic DNA was extracted from peripheral blood samples and multiplex polymerase chain reactions (PCR) analyses were performed using specific primers to confirm the presence or absence of Y chromosome microdeletions. A total of 997 patients with azoospermia and cryptozoospermia were enrolled in the study.</p><p><b>RESULTS</b>The incidence of chromosome abnormalities in the patient with azoospermia and cryptozoospermia was 28.4%. The major abnormal karyotypes included 47,XXY, 46,XY (Y>G), 46,XX, chimera and translocations. The incidence of the Y chromosome microdeletions was 17.4%. They were mainly found in the karyotypes of 46,XY and 46,XY (Y>G).</p><p><b>CONCLUSION</b>Chromosome abnormalities were the most common hereditary causes of the patients with azoospermia and cryptozoospermia. The incidence of Y chromosome microdeletion was higher in the patients with karyotype of 46,XY and 46,XY (Y>G). Therefore, detection of the AZF microdeletion in these patients is helpful to determine the etiology and avoid the unnecessary treatment and vertical transmission of the genetic defects.</p>

Attenuation of myocardial apoptosis by alpha-lipoic acid through suppression of mitochondrial oxidative stress to reduce diabetic cardiomyopathy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Cardiac failure is a leading cause of the mortality of diabetic patients. In part this is due to a specific cardiomyopathy, referred to as diabetic cardiomyopathy. Oxidative stress is widely considered to be one of the major factors underlying the pathogenesis of the disease. This study aimed to test whether the antioxidant alpha-lipoic acid (alpha-LA) could attenuate mitochondrion-dependent myocardial apoptosis through suppression of mitochondrial oxidative stress to reduce diabetic cardiomyopathy.</p><p><b>METHODS</b>A rat model of diabetes was induced by a single tail intravenous injection of streptozotocin (STZ) 45 mg/kg. Experimental animals were randomly assigned to 3 groups: normal control (NC), diabetes (DM) and DM treated with alpha-LA (alpha-LA). The latter group was administered with alpha-LA (100 mg/kg ip per day), the remainder received the same volume vehicle. At weeks 4, 8, and 12 after the onset of diabetes, cardiac apoptosis was examined by TUNEL assay. Cardiomyopathy was evaluated by assessment of cardiac structure and function. Oxidative damage was evaluated by the content of malondialdehyde (MDA), reduced glutathione (GSH) and the activity of manganese superoxide diamutase (Mn-SOD) in the myocardial mitochondria. Expression of caspase-9 and caspase-3 proteins was determined by immunohistochemistry and mitochondrial cytochrome c release was detected by Western blotting.</p><p><b>RESULTS</b>At 4, 8, and 12 weeks after the onset of diabetes, significant reductions in TUNEL-positive cells, caspase-9,-3 expression, and mitochondrial cytochrome c release were observed in the alpha-LA group compared to the DM group. In the DM group, the content of MDA in the myocardial mitochondria was significantly increased, and there was a decrease in both the mitochondrial GSH content and the activities of Mn-SOD. They were significantly improved by alpha-LA treatment. HE staining displayed structural abnormalities in diabetic hearts, while alpha-LA reversed this structural derangement. The index of cardiac function (+/-dp/dtmax) in the diabetes group was aggravated progressively from 4 weeks to 12 weeks, but alpha-LA delayed deterioration of cardiac function (P < 0.05).</p><p><b>CONCLUSIONS</b>Our findings indicate that the antioxidant alpha-LA can effectively attenuate mitochondria-dependent cardiac apoptosis and exert a protective role against the development of diabetic cardiomyopathy. The ability of alpha-LA to suppress mitochondrial oxidative damage is concomitant with an enhancement of Mn-SOD activity and an increase in the GSH content of myocardial mitochondria.</p>

Mitochondrial gene mutations and type 2 diabetes in Chinese families / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Numerous mitochondrial DNA mutations are significantly correlated with development of diabetes. This study investigated mitochondrial gene, point mutations in patients with type 2 diabetes and their families.</p><p><b>METHODS</b>Unrelated patients with type 2 diabetes (n = 826) were randomly recruited; unrelated and nondiabetic subjects (n = 637) served as controls. The clinical and biochemical data of the participants were collected. Total genome was extracted from peripheral leucocytes. Polymerase chain reaction, restriction fragment length polymorphism (PCR-RFLP) and cloning techniques were used to screen mitochondrial genes including np3316, np3394 and np3426 in the ND1 region and np3243 in the tRNA(Leu(UUR)).</p><p><b>RESULTS</b>In 39 diabetics with one or more mitochondrial gene point mutations, the prevalence (4.7%, 39/826) of mtDNA mutations was higher than that (0.7%, 5/637) in the controls. The identical mutation was found in 23 of 43 tested members from three pedigrees. Affected family members presented with variable clinical features ranging from normal glucose tolerance to impaired glucose tolerance (IGT) (n = 2), impaired fasting glucose (IFG) (n = 1) to type 2 diabetes (n = 13) with 3 family members suffering from hearing loss.</p><p><b>CONCLUSIONS</b>Type 2 diabetes in China is associated with several mitochondrial gene mutations. Aged patients with diabetic family history had a higher prevalence of mutation and various clinical pictures. Mitochondrial gene mutation might be one of the genetic factors contributing to diabetic familial clustering.</p>

Study on the mitochondrial DNA mutations in patients with early-onset diabetes mellitus / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the prevalence of mitochondrial DNA (mtDNA) mutations in patients with early-onset diabetes in Tianjin, and to explore the relationship between mtDNA mutations and diabetes.</p><p><b>METHODS</b>348 non-related patients whose age at onset of diabetes was less than 45 years were randomly recruited, and 207 non-related and non-diabetic subjects were enrolled as controls. All their clinical and biochemical data were collected. Total genome was extracted conventionally from the participants' peripheral leucocytes, and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and cloning techniques were applied to the screening of mtDNA mutations (including the 3316, 3394 and 3426 in ND1 region, 12026 in ND4 region, and tRNA [Leu(UUR)] 3243 A-->G mutation).</p><p><b>RESULTS</b>The authors found 17 diabetics harboring the 12026 A-->G mutation in ND4 region (4.9%), 10 diabetics with mutations in ND1 region (including 5 diabetics with the 3394 T-->C mutation, 4 diabetics with 3316 G-->A mutation, one with 3426 A-->G mutation), and only two with the known 3243 A-->G mutation (0.6%). On the contrary, one control subject with the 3316 G-->A mutation, two with 3394 T-->C mutation and four with 12026 A-->G mutation were found. The prevalence of mtDNA mutations in the patient group is significantly higher than that in the control group (3.3%) (P<0.05).</p><p><b>CONCLUSION</b>The above findings suggest that mtDNA mutation may be implicated in the pathogenesis of the examined diabetes.</p>

Dexamethasone-induced differentiation of pancreatic AR42J cell involves p21(waf1/cip1)and MAP kinase pathway

Dexamethasone converts pluripotent pancreatic AR42J cells into exocrine cells expressing digestive enzymes. In order to address molecular mechanism of this differentiation, we have investigated the role of mitogen-activated protein (MAP) kinase pathway and gene expressions of p21(waf1/cip1)and nuclear oncogenes (c-fos and c-myc) during AR42J cell differentiation. Dexamethasone markedly increased the intracellular and secreted amylase contents as well as its mRNA level. However, cell growth and DNA content were significantly decreased. With these phenotypic changes, AR42J cells induced transient mRNA expression of p21(waf1/cip1)gene, which reached maximal level by 6 h and then declined gradually toward basal state. In contrast to p21(waf1/cip1), c-fos gene expression was transiently inhibited by 6 h and then recovered to basal level by 24 h. Increased c-myc expression detected after 3 h, peaked by 12 h, and remained elevated during the rest of observation. Dexamethasone inhibited epidermal growth factor-induced phosphorylation of extracellular signal regulated kinase. Inhibition of MAP kinase pathway by PD98059 resulted in further elevation of the dexamethasone-induced amylase mRNA and p21(waf1/cip1)gene expression. These results suggest that p21(waf1/cip1)and nuclear oncogenes are involved in dexamethasone-induced differentiation and inhibition of MAP kinase pathway accelerates the conversion of undifferentiated AR42J cells into amylase-secreting exocrine cells.

Transduction of Tat-Superoxide Dismutase into Insulin-producing MIN6N Cells Reduces Streptozotocin-induced Cytotoxicity

The reactive oxygen species (ROS) are considered to be an important mediator in pancreatic beta cell destruction, thereby triggering the development of insulin-dependent diabetes mellitus. In the present study, HIV-1 Tat-mediated transduction of Cu, Zn-superoxide dismutase (SOD) was investigated to evaluate its protective potential against streptozotocin (STZ) -induced cytotoxicity in insulin-producing MIN6N cells. Tat-SOD fusion protein was successfully delivered into MIN6N cells in a dose-dependent manner and the transduced fusion protein was enzymatically active for 48 h. The STZ induced-cell destruction, superoxide anion radical production, and DNA fragmentation of MIN6N cells were significantly decreased in the cells pretreated with Tat-SOD for 1 h. Furthermore, the transduction of Tat-SOD increased Bcl-2 and heat shock protein 70 (hsp70) expressions in cells exposed to STZ, which might be partly responsible for the effect of Tat-SOD. These results suggest that an increased of free radical scavenging activity by transduction of Tat-SOD enhanced the tolerance of the cell against oxidative stress in STZ-treated MIN6N cells. Therefore, this Tat-SOD transduction technique may provide a new strategy to protect the pancreatic beta cell destruction in ROS-mediated diabetes.