Theoretical analysis of the DNA dynamics reveals that interaction between the single solitons and plane wave implies Smale-horseshoe chaos in the double helices. Solutions of the chaotic solitons are derived from a di...Theoretical analysis of the DNA dynamics reveals that interaction between the single solitons and plane wave implies Smale-horseshoe chaos in the double helices. Solutions of the chaotic solitons are derived from a direct perturbation technique. It is demonstrated that to produce the bounded chaotic solitons, velocities of the solit ons nust be the same and equal to propagation velocity of the plane wave in DNA. The result shows that the DNA structure may be destroyed by the long action of an electromagnetic wave. It also supplies a useful method for controlling the velocities and unboundedness of the DNA motion in a tumour cell by using a plane wave.展开更多
BACKGROUND Gastric cancer(GC) ranks as the third leading cause of cancer-related death worldwide. Epigenetic alterations contribute to tumor heterogeneity in early stages.AIM To identify the specific deoxyribonucleic ...BACKGROUND Gastric cancer(GC) ranks as the third leading cause of cancer-related death worldwide. Epigenetic alterations contribute to tumor heterogeneity in early stages.AIM To identify the specific deoxyribonucleic acid(DNA) methylation sites that influence the prognosis of GC patients and explore the prognostic value of a model based on subtypes of DNA methylation.METHODS Patients were randomly classified into training and test sets. Prognostic DNA methylation sites were identified by integrating DNA methylation profiles and clinical data from The Cancer Genome Atlas GC cohort. In the training set, unsupervised consensus clustering was performed to identify distinct subgroups based on methylation status. A risk score model was built based on Kaplan-Meier, least absolute shrinkage and selector operation, and multivariate Cox regression analyses. A test set was used to validate this model.RESULTS Three subgroups based on DNA methylation profiles in the training set were identified using 1061 methylation sites that were significantly associated with survival. These methylation subtypes reflected differences in T, N, and M category, age, stage, and prognosis. Forty-one methylation sites were screened as specific hyper-or hypomethylation sites for each specific subgroup. Enrichment analysis revealed that they were mainly involved in pathways related to carcinogenesis, tumor growth, and progression. Finally, two methylation sites were chosen to generate a prognostic model. The high-risk group showed a markedly poor prognosis compared to the low-risk group in both the training [hazard ratio(HR) = 2.24, 95% confidence interval(CI): 1.28-3.92, P < 0.001] and test(HR = 2.12, 95%CI: 1.19-3.78, P = 0.002) datasets.CONCLUSION DNA methylation-based classification reflects the epigenetic heterogeneity of GC and may contribute to predicting prognosis and offer novel insights for individualized treatment of patients with GC.展开更多
A retrospective study of flow cytometric measurements on paraffin-embedded tumor specimens from 188 patients with bladder tumor was conducted. The results were analyzed in combination with the morphological variation ...A retrospective study of flow cytometric measurements on paraffin-embedded tumor specimens from 188 patients with bladder tumor was conducted. The results were analyzed in combination with the morphological variation of bladder tumors. It was found that the DNA ploid pottern, degree of infiltration and the multiplicity of bladder tumor were closely related with tumor recurrence, among which the DNA ploid pattern was most significant. In aneuploid bladder tumors the recurrent rate and mean annual recurrence frequency were 76.7% and 1.46, and those in the diploid bladder tumors were 18.7% and 0.33 respectively. Aneuploid was the most indicative parameter of the recurrence in bladder tumors. In addition, according to the DNA ploid pattern and DNA index (DI), the aneuploid tumors in our group were divided into 4 types, namely, tetraploid tumors, npn-euploid with DI(?)1.5, non-euploid tumors with DI>1.5 and two-aneuploid tumors. The results showed that the recurrent rate of tetraploid tumors was relatively lower and it became higher and higher in the following order: non-euploid tumors with DI(?)1.5, non-euploid tumors with DI>1.5, and two-aneuploid tumors. This indicates that there are different biological behaviors in tumors with different ploid pattern. Finally, the correlation between DNA ploid pattern and tumor metastasis was also discussed.展开更多
Curcumin is a member of the polyphenol family with various functionalities.Its application as a functional food,however,is currently limited by the low stability,bioaccessibility,redispersibility,and solubilization.Th...Curcumin is a member of the polyphenol family with various functionalities.Its application as a functional food,however,is currently limited by the low stability,bioaccessibility,redispersibility,and solubilization.The purpose of the study is to explore the fish sperm deoxyribonucleic acid encapsulation to solve these challenges of curcumin.Curcumin was encapsulated by fish sperm deoxyribonucleic acid using a pH cycle method.The fish sperm deoxyribonucleic acid-to-curcumin mass ratio was inversely proportional to the mean size and positively related to the encapsulation efficiency,the highlight of which is the high loading capacity.Fish sperm deoxyribonucleic acid/curcumin,that amorphous,presented sphere mainly driven by hydrogen bonding and hydrophobic effects.It was stable at pH 2.5-8.0 due to its high surface charges,stable after heating at 80,115,and 120◦C respectively,and slow the curcumin degradation during storage.NaCl had basically no effect on its stability.It improved bioaccessibility to 58.07μg/ml due to its structural integrity in the stomach.Furthermore,it exhibited excellent redispersibility and solubilization after freeze-drying.Based on the obtained results,pH cycle fish sperm deoxyribonucleic acid encapsulation is an effective strategy to improve the stability,bioaccessibility,redispersibility,and solubilization of curcumin.This study provides new ideas for the wide application of functional food ingredients assisted by biopolymers.展开更多
Gallium nitride- （GaN） based high electron mobility transistors （HEMTs） provide a good platform for biological detection. In this work, both Au-gated AlInN/GaN HEMT and AlGaN/GaN HEMT biosensors are fabricated for...Gallium nitride- （GaN） based high electron mobility transistors （HEMTs） provide a good platform for biological detection. In this work, both Au-gated AlInN/GaN HEMT and AlGaN/GaN HEMT biosensors are fabricated for the detection of deoxyribonucleic acid （DNA） hybridization. The Au-gated AIInN/GaN HEMT biosensor exhibits higher sensitivity in comparison with the AlGaN/GaN HEMT biosensor. For the former, the drain-source current （VDS = 0.5 V） shows a clear decrease of 69μA upon the introduction of 1μmolL^-1 （μM） complimentary DNA to the probe DNA at the sensor area, while for the latter it is only 38 μA. This current reduction is a notable indication of the hybridization. The high sensitivity can be attributed to the thinner barrier of the AlInN/GaN heterostructure, which makes the two-dimensional electron gas channel more susceptible to a slight change of the surface charge.展开更多
Introduction: Transitioning to more efficacious Antiretrovirals for HIV infected pregnant women and infant prophylaxis has reduced Mother to child transmission of HIV significantly. This study aimed to determine HIV i...Introduction: Transitioning to more efficacious Antiretrovirals for HIV infected pregnant women and infant prophylaxis has reduced Mother to child transmission of HIV significantly. This study aimed to determine HIV infection status in HIVexposed infants who had their first DNA polymerase chain reaction test in our molecular Laboratory. Subjects, Materials and Methods: Dried Blood Spots for HIV DNA results from 5 states between 2009 and 2020 were analyzed in the PCR laboratory of the Federal Teaching Hospital, Gombe. Results: Nine thousand eight hundred and twenty-three Human Immunodeficiency Virus Deoxyribonucleic acid polymerase Chain Reaction results were analysed;4937 (50.2%) were males. During the study period, there was an overall declining trend in the mother-to-child transmission rate from 3.8% in 2009 to 1.0% in 2020. 6120 (62.3%) of HIV + mothers received Highly active antiretroviral therapy HAART before pregnancy. 7845 (76.2%) of the infants received Nevirapine prophylaxis. Dried blood spot samples were collected from 4077 (41.5%) at 6 - 8 weeks. 8438 (85.9%) received cotrimoxazole. 9469 (96.4%) were ever breastfed. Of the 9823 HIV DNA PCR results, 255 (2.6%) were positive while 69/4077 (1.7%) and 109/2662 (4.1%) were positive for HIV DNA at 6 - 8 weeks and > 12 weeks respectively. (p = 0.001). 86/747 (11.5%) of infants whose HIV-positive mothers received no ARVS were HIV DNA positive. (p = 0.001). 106/884 (12.0%) of infants who had no Antiretroviral prophylaxis had positive HIV DNA results;7/413 (1.7%) with Zidovudine/Nevirapine prophylaxis had positive results. (p = 0.001). 246/9469 (2.6%) of infants that were ever breastfed were positive for HIV DNA;11/354 (3.0%) that never breastfed had positive HIV DNA. Conclusion: Lack of maternal/infant ARVs and prolonged breastfeeding increased the risk of infant HIV infection.展开更多
Two new copper complexes based on 2-naphthoxyacetic acid ligand, namely [Cu(L)2(CH3CN)]2(1) and [Cu(L)(1,10-phen)2](2), where L = 2-naphthoxyacetic acid and 1,10-phen = 1,10-phenanthroline, were obtained by hydrotherm...Two new copper complexes based on 2-naphthoxyacetic acid ligand, namely [Cu(L)2(CH3CN)]2(1) and [Cu(L)(1,10-phen)2](2), where L = 2-naphthoxyacetic acid and 1,10-phen = 1,10-phenanthroline, were obtained by hydrothermal reaction and characterized by single-crystal X-ray diffraction. The binuclear complex 1 and mononuclear complex 2 belong to space group C2/c and P■, respectively. The binding properties of the two compounds with ct-DNA were investigated by UV-Vis and fluorescence spectra. The two compounds could bind with ct-DNA through interactions. Compound 2 displays stronger binding ability in the reaction with ct-DNA.展开更多
A new complex Mn(Htpc)2(H2O)2(1, Htpc = 5-(trifluoromethyl)pyridine-2-carboxylic acid) has been synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. 1 belongs to triclinic ...A new complex Mn(Htpc)2(H2O)2(1, Htpc = 5-(trifluoromethyl)pyridine-2-carboxylic acid) has been synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. 1 belongs to triclinic system, space group P■ with a = 5.0885(10), b = 6.5574(13), c = 14.016(3) ?, β = 90.67(3)o, V = 436.34(17) ?3, Z = 1, Dc = 1.793 g·cm-3, μ = 0.855 mm-1, Mr = 471.18, F(000) = 235, the final R = 0.0454 and wR = 0.1134 for 1998 observed reflections with I > 2σ(I). The Mn(Ⅱ) ion is coordinated by two N and two O atoms from two Htpc as well as two O atoms from two coordinated water molecules, forming a 0D motif with distorted octahedral coordinate geometry. The adjacent 0D units are linked into 1D chains through hydrogen bond O(1W)–H(1 WB)···O(2), and via the O(1 W)–H(1 WA)···O(1) hydrogen bond the neighboring 1D chains are connected into a 2D supramolecular layer. Moreover, the interactions between the ligand and its complex with CT-DNA were studied by EtBr fluorescence probe, which suggested that these compounds bind to CT-DNA through an intercalation mode. The binding constants were 0.41 and 0.64 for Htpc and complex 1, respectively. It indicates that the interaction between complex 1 and CT-DNA is stronger than Htpc.展开更多
The protective roles of α-lipoic acid in the rat model of mitochondrial DNA (mtDNA) 4834bp deletion in inner ear were investigated. Forty female Wistar rats at 4 weeks of age were divided into four groups: group A (D...The protective roles of α-lipoic acid in the rat model of mitochondrial DNA (mtDNA) 4834bp deletion in inner ear were investigated. Forty female Wistar rats at 4 weeks of age were divided into four groups: group A (D-galactose group, n=10), group B (D-galactose+α-lipoic acid group, n=10), group C (α-lipoic acid group, n=10), and group D (control group, n=10). Auditory brainstem response (ABR) was used to detect the hearing threshold. Colorimetry was used to analyze activity of superoxide dismutase (SOD) and concentration of malondialdehyde (MDA). The percentage of mtDNA4834bp deletion in inner ear was identified by real-time PCR. There was no significant difference in ABR threshold shift among all groups. The percentage of mtDNA4834bp deletion in group A was higher than that in other groups, but there was no significant difference in percentage of mtDNA4834bp deletion among groups B, C, and D. The activity of SOD in group A was lower than that in other groups. The concentration of MDA in group A was higher than that in other groups. It was concluded that there was no significant hearing loss when the percentage of mtDNA4834bp deletion was lower than 12.5%. α-Lipoic acid could prevent the reactive oxygen species (ROS)-induced mtDNA4834bp deletion in inner ear of rats.展开更多
O6-methylguanine DNA methyltransferase(MGMT), a DNA repair enzyme, has been reported in some congenital malformations, but it is less frequently reported in neural tube defects. This study investigated MGMT mRNA expre...O6-methylguanine DNA methyltransferase(MGMT), a DNA repair enzyme, has been reported in some congenital malformations, but it is less frequently reported in neural tube defects. This study investigated MGMT mRNA expression and methylation levels in the early embryo and in different embryonic stages, as well as the relationship between MGMT and neural tube defects. Spina bifida aperta was induced in rats by a single intragastric administration of all-trans retinoic acid on embryonic day(E) 10, whereas normal control rats received the same amount of olive oil on the same embryonic day. DNA damage was assessed by detecting γ-H2 A.X in spina bifida aperta rats. Real time-polymerase chain reaction was used to examine mRNA expression of MGMT in normal control and spina bifida aperta rats. In normal controls, the MGMT mRNA expression decreased with increasing embryonic days, and was remarkably reduced from E11 to E14, reaching a minimum at E18. In the spina bifida aperta model, γ-H2 A.X protein expression was increased, and mRNA expression of MGMT was markedly decreased on E14, E16, and E18. Bisulfite sequencing polymerase chain reaction for MGMT promoter methylation demonstrated that almost all CpG sites in the MGMT promoter remained unmethylated in both spina bifida aperta rats and normal controls, and there was no significant difference in methylation level between the two groups on either E14 or E18. Our results show that DNA damage occurs in spina bifida aperta rats. The mRNA expression of MGMT is downregulated, and this downregulation is independent of promoter DNA methylation.展开更多
Colorectal cancer(CRC) has been designated a major global problem, especially due to its high prevalence in developed countries. CRC mostly occurs sporadically(75%-80%), and only 20%-25% of patients have a family hist...Colorectal cancer(CRC) has been designated a major global problem, especially due to its high prevalence in developed countries. CRC mostly occurs sporadically(75%-80%), and only 20%-25% of patients have a family history.Several processes are involved in the development of CRC such as a combination of genetic and epigenetic alterations. Epigenetic changes, including DNA methylation play a vital role in the progression of CRC. Complex interactions between susceptibility genes and environmental factors, such as a diet and sedentary lifestyle, lead to the development of CRC. Clinical and experimental studies have confirmed the beneficial effects of dietary polyunsaturated fatty acids(PUFAs) in preventing CRC. From a mechanistic viewpoint, it has been suggested that PUFAs are pleiotropic agents that alter chromatin remodeling,membrane structure and downstream cell signaling. Moreover, PUFAs can alter the epigenome via modulation of DNA methylation. In this review, we summarize recent investigations linking PUFAs and DNA methylationassociated CRC risk.展开更多
In this study, we compared conventional sperm selection with high-magnification morphology based on the motile sperm organellar morphology examination （MSOME） criteria, and hyaluronic acid （HA） binding for sperm c...In this study, we compared conventional sperm selection with high-magnification morphology based on the motile sperm organellar morphology examination （MSOME） criteria, and hyaluronic acid （HA） binding for sperm chromosome aneuploidy and DNA fragmentation rates. Semen from 50 severe male factor cases was processed through density gradient centrifugation, and subjected to sperm selection by using the conventional method （control）, high magnification at x6650 or HA binding. Aneuploidy was detected by fluorescence in situ hybridization with probes for chromosomes 13, 18, 21, X and Y, and DNA fragmentation by the terminal deoxynucleotidyl transferase dUTP nick end labelling （TUNEL） method. Spermatozoa selected under high-magnification had a lower DNA fragmentation rate （2.6% vs. 1.7%; P=0.032）, with no significant difference in aneuploidy rate （0.8% vs0.7%; P=0.583）, than those selected by the HA binding method. Spermatozoa selected by both methods had much lower aneuploidy and DNA fragmentation rate than the controls （7% aneuploidy and 26.8% DNA fragmentation rates, respectively）. In the high-magnification group, the aneuploidy rate was lower when the best spermatozoa were selected than when only the second-best spermatozoa were available for selection, but the DNA fragmentation rate was not different. In conclusion, sperm selection under high magnification was more effective than under HA binding in selecting spermatozoa with low DNA fragmentation rate, but the small difference （0.9%） might not be clinically meaningful. Both methods were better than the conventional method of sperm selection.展开更多
The aim of this study was to evaluate the effect of naringin on experimentally induced inflammatory bowel dis- ease in rats. Naringin （20, 40 and 80 mg/kg） was given orally for 7 days to Wistar rats before induction...The aim of this study was to evaluate the effect of naringin on experimentally induced inflammatory bowel dis- ease in rats. Naringin （20, 40 and 80 mg/kg） was given orally for 7 days to Wistar rats before induction of colitis by intrarectal instillation of 2 mL of 4% （v/v） acetic acid solution. The degree of colonic mucosal damage was analyzed by examining mucosal damage, ulcer area, ulcer index and stool consistency. Intrarectal administration of 4% acetic acid resulted in significant modulation of serum alkaline phosphatase, lactate dehydrogenase, superoxide dismutase （SOD）, glutathione （GSH）, malondialdehyde （MDA） and myeloperoxidase （MPO） content along with colonic nitric oxide （NO）, xanthine oxidase （XO） level and protein carbonyl content in the colonic tissue as well as in blood. Naringin （40 and 80 mg/kg） exerted a dose dependent （P 〈 0.05） ameliorative effect, as it significantly increased hematological parameter as well as colonic SOD and GSH. There was a significant （P 〈 0.05） and dose dependant inhibition of macroscopical score, ulcer area along with colonic MDA, MPO activity by the 7 days of pretreatment of naringin （40 and 80 mg/kg）. Biochemical studies revealed a significant （P 〈 0.05） dose dependant inhibition in serum alkaline phosphatase （ALP） and lactate dehydrogenase （LDH） levels by pretreatment of naringin. Increased levels of colonic NO, XO, protein carbonyl content and DNA damage were also sig- nificantly decreased by naringin pretreatment. The findings of the present investigation propose that naringin has an anti-inflammatory, anti-oxidant and anti-apoptotic potential effect at colorectal sites as it modulates the production and expression of oxidative mediators such as MDA, MPO, NO and XO, thus reducing DNA damage.展开更多
Glyeyrrhetinic acid (GA) is an active component of Glycyrrhiza uraleusis fisch,In this study,GA was found to inhibit ear edema and ornithine decarboxylase (ODC)activity induced by croton oil in mice. GA could also pro...Glyeyrrhetinic acid (GA) is an active component of Glycyrrhiza uraleusis fisch,In this study,GA was found to inhibit ear edema and ornithine decarboxylase (ODC)activity induced by croton oil in mice. GA could also protect rapid DNA damage and decrease the unscheduled DNA synthesis induced by benzo(α)pyrene. The results demonstrate that GA has a potential cancer chemopreventive activity.展开更多
文摘Theoretical analysis of the DNA dynamics reveals that interaction between the single solitons and plane wave implies Smale-horseshoe chaos in the double helices. Solutions of the chaotic solitons are derived from a direct perturbation technique. It is demonstrated that to produce the bounded chaotic solitons, velocities of the solit ons nust be the same and equal to propagation velocity of the plane wave in DNA. The result shows that the DNA structure may be destroyed by the long action of an electromagnetic wave. It also supplies a useful method for controlling the velocities and unboundedness of the DNA motion in a tumour cell by using a plane wave.
基金Supported by the International Science and Technology Cooperation Projects,No. 2016YFE0107100Capital Special Research Project for Health Development,No. 2014-2-4012+3 种基金Beijing Natural Science Foundation,No. L172055 and No. 7192158National Ten-thousand Talent Programthe Fundamental Research Funds for the Central Universities,No. 3332018032CAMS Innovation Fund for Medical Science (CIFMS),No. 2017-I2M-4-003 and No. 2018-I2M-3-001。
文摘BACKGROUND Gastric cancer(GC) ranks as the third leading cause of cancer-related death worldwide. Epigenetic alterations contribute to tumor heterogeneity in early stages.AIM To identify the specific deoxyribonucleic acid(DNA) methylation sites that influence the prognosis of GC patients and explore the prognostic value of a model based on subtypes of DNA methylation.METHODS Patients were randomly classified into training and test sets. Prognostic DNA methylation sites were identified by integrating DNA methylation profiles and clinical data from The Cancer Genome Atlas GC cohort. In the training set, unsupervised consensus clustering was performed to identify distinct subgroups based on methylation status. A risk score model was built based on Kaplan-Meier, least absolute shrinkage and selector operation, and multivariate Cox regression analyses. A test set was used to validate this model.RESULTS Three subgroups based on DNA methylation profiles in the training set were identified using 1061 methylation sites that were significantly associated with survival. These methylation subtypes reflected differences in T, N, and M category, age, stage, and prognosis. Forty-one methylation sites were screened as specific hyper-or hypomethylation sites for each specific subgroup. Enrichment analysis revealed that they were mainly involved in pathways related to carcinogenesis, tumor growth, and progression. Finally, two methylation sites were chosen to generate a prognostic model. The high-risk group showed a markedly poor prognosis compared to the low-risk group in both the training [hazard ratio(HR) = 2.24, 95% confidence interval(CI): 1.28-3.92, P < 0.001] and test(HR = 2.12, 95%CI: 1.19-3.78, P = 0.002) datasets.CONCLUSION DNA methylation-based classification reflects the epigenetic heterogeneity of GC and may contribute to predicting prognosis and offer novel insights for individualized treatment of patients with GC.
文摘A retrospective study of flow cytometric measurements on paraffin-embedded tumor specimens from 188 patients with bladder tumor was conducted. The results were analyzed in combination with the morphological variation of bladder tumors. It was found that the DNA ploid pottern, degree of infiltration and the multiplicity of bladder tumor were closely related with tumor recurrence, among which the DNA ploid pattern was most significant. In aneuploid bladder tumors the recurrent rate and mean annual recurrence frequency were 76.7% and 1.46, and those in the diploid bladder tumors were 18.7% and 0.33 respectively. Aneuploid was the most indicative parameter of the recurrence in bladder tumors. In addition, according to the DNA ploid pattern and DNA index (DI), the aneuploid tumors in our group were divided into 4 types, namely, tetraploid tumors, npn-euploid with DI(?)1.5, non-euploid tumors with DI>1.5 and two-aneuploid tumors. The results showed that the recurrent rate of tetraploid tumors was relatively lower and it became higher and higher in the following order: non-euploid tumors with DI(?)1.5, non-euploid tumors with DI>1.5, and two-aneuploid tumors. This indicates that there are different biological behaviors in tumors with different ploid pattern. Finally, the correlation between DNA ploid pattern and tumor metastasis was also discussed.
基金supported by the National Natural Science Foundation of China(Grant No.31871786).
文摘Curcumin is a member of the polyphenol family with various functionalities.Its application as a functional food,however,is currently limited by the low stability,bioaccessibility,redispersibility,and solubilization.The purpose of the study is to explore the fish sperm deoxyribonucleic acid encapsulation to solve these challenges of curcumin.Curcumin was encapsulated by fish sperm deoxyribonucleic acid using a pH cycle method.The fish sperm deoxyribonucleic acid-to-curcumin mass ratio was inversely proportional to the mean size and positively related to the encapsulation efficiency,the highlight of which is the high loading capacity.Fish sperm deoxyribonucleic acid/curcumin,that amorphous,presented sphere mainly driven by hydrogen bonding and hydrophobic effects.It was stable at pH 2.5-8.0 due to its high surface charges,stable after heating at 80,115,and 120◦C respectively,and slow the curcumin degradation during storage.NaCl had basically no effect on its stability.It improved bioaccessibility to 58.07μg/ml due to its structural integrity in the stomach.Furthermore,it exhibited excellent redispersibility and solubilization after freeze-drying.Based on the obtained results,pH cycle fish sperm deoxyribonucleic acid encapsulation is an effective strategy to improve the stability,bioaccessibility,redispersibility,and solubilization of curcumin.This study provides new ideas for the wide application of functional food ingredients assisted by biopolymers.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFB0400104 and2016YFB0400301the National Natural Sciences Foundation of China under Grant No 61334002the National Science and Technology Major Project
文摘Gallium nitride- （GaN） based high electron mobility transistors （HEMTs） provide a good platform for biological detection. In this work, both Au-gated AlInN/GaN HEMT and AlGaN/GaN HEMT biosensors are fabricated for the detection of deoxyribonucleic acid （DNA） hybridization. The Au-gated AIInN/GaN HEMT biosensor exhibits higher sensitivity in comparison with the AlGaN/GaN HEMT biosensor. For the former, the drain-source current （VDS = 0.5 V） shows a clear decrease of 69μA upon the introduction of 1μmolL^-1 （μM） complimentary DNA to the probe DNA at the sensor area, while for the latter it is only 38 μA. This current reduction is a notable indication of the hybridization. The high sensitivity can be attributed to the thinner barrier of the AlInN/GaN heterostructure, which makes the two-dimensional electron gas channel more susceptible to a slight change of the surface charge.
文摘Introduction: Transitioning to more efficacious Antiretrovirals for HIV infected pregnant women and infant prophylaxis has reduced Mother to child transmission of HIV significantly. This study aimed to determine HIV infection status in HIVexposed infants who had their first DNA polymerase chain reaction test in our molecular Laboratory. Subjects, Materials and Methods: Dried Blood Spots for HIV DNA results from 5 states between 2009 and 2020 were analyzed in the PCR laboratory of the Federal Teaching Hospital, Gombe. Results: Nine thousand eight hundred and twenty-three Human Immunodeficiency Virus Deoxyribonucleic acid polymerase Chain Reaction results were analysed;4937 (50.2%) were males. During the study period, there was an overall declining trend in the mother-to-child transmission rate from 3.8% in 2009 to 1.0% in 2020. 6120 (62.3%) of HIV + mothers received Highly active antiretroviral therapy HAART before pregnancy. 7845 (76.2%) of the infants received Nevirapine prophylaxis. Dried blood spot samples were collected from 4077 (41.5%) at 6 - 8 weeks. 8438 (85.9%) received cotrimoxazole. 9469 (96.4%) were ever breastfed. Of the 9823 HIV DNA PCR results, 255 (2.6%) were positive while 69/4077 (1.7%) and 109/2662 (4.1%) were positive for HIV DNA at 6 - 8 weeks and > 12 weeks respectively. (p = 0.001). 86/747 (11.5%) of infants whose HIV-positive mothers received no ARVS were HIV DNA positive. (p = 0.001). 106/884 (12.0%) of infants who had no Antiretroviral prophylaxis had positive HIV DNA results;7/413 (1.7%) with Zidovudine/Nevirapine prophylaxis had positive results. (p = 0.001). 246/9469 (2.6%) of infants that were ever breastfed were positive for HIV DNA;11/354 (3.0%) that never breastfed had positive HIV DNA. Conclusion: Lack of maternal/infant ARVs and prolonged breastfeeding increased the risk of infant HIV infection.
基金supported by the National Natural Science Foundation of China(21101090 and 21561021)
文摘Two new copper complexes based on 2-naphthoxyacetic acid ligand, namely [Cu(L)2(CH3CN)]2(1) and [Cu(L)(1,10-phen)2](2), where L = 2-naphthoxyacetic acid and 1,10-phen = 1,10-phenanthroline, were obtained by hydrothermal reaction and characterized by single-crystal X-ray diffraction. The binuclear complex 1 and mononuclear complex 2 belong to space group C2/c and P■, respectively. The binding properties of the two compounds with ct-DNA were investigated by UV-Vis and fluorescence spectra. The two compounds could bind with ct-DNA through interactions. Compound 2 displays stronger binding ability in the reaction with ct-DNA.
基金Supported by the Scientific Research Foundation of Higher Education Institutions of Ningxia(No.NGY2017004)the National Natural Science Foundation of China(Nos.21763022 and 50564043)the Major Innovation Projects for Building First-class Universities in China’s Western Region(No.ZKZD2017003)
文摘A new complex Mn(Htpc)2(H2O)2(1, Htpc = 5-(trifluoromethyl)pyridine-2-carboxylic acid) has been synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. 1 belongs to triclinic system, space group P■ with a = 5.0885(10), b = 6.5574(13), c = 14.016(3) ?, β = 90.67(3)o, V = 436.34(17) ?3, Z = 1, Dc = 1.793 g·cm-3, μ = 0.855 mm-1, Mr = 471.18, F(000) = 235, the final R = 0.0454 and wR = 0.1134 for 1998 observed reflections with I > 2σ(I). The Mn(Ⅱ) ion is coordinated by two N and two O atoms from two Htpc as well as two O atoms from two coordinated water molecules, forming a 0D motif with distorted octahedral coordinate geometry. The adjacent 0D units are linked into 1D chains through hydrogen bond O(1W)–H(1 WB)···O(2), and via the O(1 W)–H(1 WA)···O(1) hydrogen bond the neighboring 1D chains are connected into a 2D supramolecular layer. Moreover, the interactions between the ligand and its complex with CT-DNA were studied by EtBr fluorescence probe, which suggested that these compounds bind to CT-DNA through an intercalation mode. The binding constants were 0.41 and 0.64 for Htpc and complex 1, respectively. It indicates that the interaction between complex 1 and CT-DNA is stronger than Htpc.
基金supported by grants from the State Key Program of National Natural Science of China (No. 30730094)the National Science & Technology Pillar Program during the Eleventh Five-year Plan Period (No. 2007BAI18B13)
文摘The protective roles of α-lipoic acid in the rat model of mitochondrial DNA (mtDNA) 4834bp deletion in inner ear were investigated. Forty female Wistar rats at 4 weeks of age were divided into four groups: group A (D-galactose group, n=10), group B (D-galactose+α-lipoic acid group, n=10), group C (α-lipoic acid group, n=10), and group D (control group, n=10). Auditory brainstem response (ABR) was used to detect the hearing threshold. Colorimetry was used to analyze activity of superoxide dismutase (SOD) and concentration of malondialdehyde (MDA). The percentage of mtDNA4834bp deletion in inner ear was identified by real-time PCR. There was no significant difference in ABR threshold shift among all groups. The percentage of mtDNA4834bp deletion in group A was higher than that in other groups, but there was no significant difference in percentage of mtDNA4834bp deletion among groups B, C, and D. The activity of SOD in group A was lower than that in other groups. The concentration of MDA in group A was higher than that in other groups. It was concluded that there was no significant hearing loss when the percentage of mtDNA4834bp deletion was lower than 12.5%. α-Lipoic acid could prevent the reactive oxygen species (ROS)-induced mtDNA4834bp deletion in inner ear of rats.
基金supported by the National Natural Science Foundation of China,No.81671469,81171072(to ZWY)the National Basic Research Program of China(973 Program),No.2013CB945402(to ZWY)the Program for Liaoning Innovative Research Team in University of China,No.LT2013016(to ZWY)
文摘O6-methylguanine DNA methyltransferase(MGMT), a DNA repair enzyme, has been reported in some congenital malformations, but it is less frequently reported in neural tube defects. This study investigated MGMT mRNA expression and methylation levels in the early embryo and in different embryonic stages, as well as the relationship between MGMT and neural tube defects. Spina bifida aperta was induced in rats by a single intragastric administration of all-trans retinoic acid on embryonic day(E) 10, whereas normal control rats received the same amount of olive oil on the same embryonic day. DNA damage was assessed by detecting γ-H2 A.X in spina bifida aperta rats. Real time-polymerase chain reaction was used to examine mRNA expression of MGMT in normal control and spina bifida aperta rats. In normal controls, the MGMT mRNA expression decreased with increasing embryonic days, and was remarkably reduced from E11 to E14, reaching a minimum at E18. In the spina bifida aperta model, γ-H2 A.X protein expression was increased, and mRNA expression of MGMT was markedly decreased on E14, E16, and E18. Bisulfite sequencing polymerase chain reaction for MGMT promoter methylation demonstrated that almost all CpG sites in the MGMT promoter remained unmethylated in both spina bifida aperta rats and normal controls, and there was no significant difference in methylation level between the two groups on either E14 or E18. Our results show that DNA damage occurs in spina bifida aperta rats. The mRNA expression of MGMT is downregulated, and this downregulation is independent of promoter DNA methylation.
文摘Colorectal cancer(CRC) has been designated a major global problem, especially due to its high prevalence in developed countries. CRC mostly occurs sporadically(75%-80%), and only 20%-25% of patients have a family history.Several processes are involved in the development of CRC such as a combination of genetic and epigenetic alterations. Epigenetic changes, including DNA methylation play a vital role in the progression of CRC. Complex interactions between susceptibility genes and environmental factors, such as a diet and sedentary lifestyle, lead to the development of CRC. Clinical and experimental studies have confirmed the beneficial effects of dietary polyunsaturated fatty acids(PUFAs) in preventing CRC. From a mechanistic viewpoint, it has been suggested that PUFAs are pleiotropic agents that alter chromatin remodeling,membrane structure and downstream cell signaling. Moreover, PUFAs can alter the epigenome via modulation of DNA methylation. In this review, we summarize recent investigations linking PUFAs and DNA methylationassociated CRC risk.
文摘In this study, we compared conventional sperm selection with high-magnification morphology based on the motile sperm organellar morphology examination （MSOME） criteria, and hyaluronic acid （HA） binding for sperm chromosome aneuploidy and DNA fragmentation rates. Semen from 50 severe male factor cases was processed through density gradient centrifugation, and subjected to sperm selection by using the conventional method （control）, high magnification at x6650 or HA binding. Aneuploidy was detected by fluorescence in situ hybridization with probes for chromosomes 13, 18, 21, X and Y, and DNA fragmentation by the terminal deoxynucleotidyl transferase dUTP nick end labelling （TUNEL） method. Spermatozoa selected under high-magnification had a lower DNA fragmentation rate （2.6% vs. 1.7%; P=0.032）, with no significant difference in aneuploidy rate （0.8% vs0.7%; P=0.583）, than those selected by the HA binding method. Spermatozoa selected by both methods had much lower aneuploidy and DNA fragmentation rate than the controls （7% aneuploidy and 26.8% DNA fragmentation rates, respectively）. In the high-magnification group, the aneuploidy rate was lower when the best spermatozoa were selected than when only the second-best spermatozoa were available for selection, but the DNA fragmentation rate was not different. In conclusion, sperm selection under high magnification was more effective than under HA binding in selecting spermatozoa with low DNA fragmentation rate, but the small difference （0.9%） might not be clinically meaningful. Both methods were better than the conventional method of sperm selection.
文摘The aim of this study was to evaluate the effect of naringin on experimentally induced inflammatory bowel dis- ease in rats. Naringin （20, 40 and 80 mg/kg） was given orally for 7 days to Wistar rats before induction of colitis by intrarectal instillation of 2 mL of 4% （v/v） acetic acid solution. The degree of colonic mucosal damage was analyzed by examining mucosal damage, ulcer area, ulcer index and stool consistency. Intrarectal administration of 4% acetic acid resulted in significant modulation of serum alkaline phosphatase, lactate dehydrogenase, superoxide dismutase （SOD）, glutathione （GSH）, malondialdehyde （MDA） and myeloperoxidase （MPO） content along with colonic nitric oxide （NO）, xanthine oxidase （XO） level and protein carbonyl content in the colonic tissue as well as in blood. Naringin （40 and 80 mg/kg） exerted a dose dependent （P 〈 0.05） ameliorative effect, as it significantly increased hematological parameter as well as colonic SOD and GSH. There was a significant （P 〈 0.05） and dose dependant inhibition of macroscopical score, ulcer area along with colonic MDA, MPO activity by the 7 days of pretreatment of naringin （40 and 80 mg/kg）. Biochemical studies revealed a significant （P 〈 0.05） dose dependant inhibition in serum alkaline phosphatase （ALP） and lactate dehydrogenase （LDH） levels by pretreatment of naringin. Increased levels of colonic NO, XO, protein carbonyl content and DNA damage were also sig- nificantly decreased by naringin pretreatment. The findings of the present investigation propose that naringin has an anti-inflammatory, anti-oxidant and anti-apoptotic potential effect at colorectal sites as it modulates the production and expression of oxidative mediators such as MDA, MPO, NO and XO, thus reducing DNA damage.
文摘Glyeyrrhetinic acid (GA) is an active component of Glycyrrhiza uraleusis fisch,In this study,GA was found to inhibit ear edema and ornithine decarboxylase (ODC)activity induced by croton oil in mice. GA could also protect rapid DNA damage and decrease the unscheduled DNA synthesis induced by benzo(α)pyrene. The results demonstrate that GA has a potential cancer chemopreventive activity.
