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Hao YH, Tang XB, Wang DZ. [Atypical teratoid/rhabdoid tumors in adult patients: report of two cases]. Zhonghua Bing Li Xue Za Zhi 2022; 51:1171-1173. [PMID: 36323552 DOI: 10.3760/cma.j.cn112151-20220424-00326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Affiliation(s)
- Y H Hao
- Department of Pathology, Taihe Hospital, Hubei University of Medicine, Shiyan 442000, China
| | - X B Tang
- Department of Pathology, Taihe Hospital, Hubei University of Medicine, Shiyan 442000, China
| | - D Z Wang
- Department of Pathology, Taihe Hospital, Hubei University of Medicine, Shiyan 442000, China
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Wang L, Hao YH, Bai Y. [Public health and clinical care integration to improve immunization of children with special health care needs]. Zhonghua Yu Fang Yi Xue Za Zhi 2022; 56:673-678. [PMID: 35785850 DOI: 10.3760/cma.j.cn112150-20220104-00010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Immunization of children with special health care needs has always been one of the difficulties in community-level public health. In recent years the relevant consensus opinions on vaccination have been issued in China, but for a long time there is a lack of effective communication channels between disease prevention and clinical medical systems in China. Pediatricians play an unoccupied role in immunization, and community-level vaccinators face the difficulties including dilemma of disease identification, evidence-based evaluation and upward referral. These lead to the vaccination hesitancy, thus the multi-disciplinary management and three-level referral model of children with special health care needs should be improved urgently. It should strengthen the integration of public health and clinical care, with the active participation of pediatricians, to promote the immunization of children with special health care needs effectively.
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Affiliation(s)
- L Wang
- Department of Child Health Care, Children's Hospital, Capital Institute of Pediatrics, Beijing 100020, China
| | - Y H Hao
- Division of Immunization Programme, Chinese Center for Disease Control and Prevention, Beijing 100050, China
| | - Yunhua Bai
- Chaoyang District Center for Disease Control and Prevention,Beijing 100021, China
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Bi X, Zhang Q, Fan K, Tang S, Guan H, Gao X, Cui Y, Ma Y, Wu Q, Hao Y, Ning N, Liu C. Risk Culture and COVID-19 Protective Behaviors: A Cross-Sectional Survey of Residents in China. Front Public Health 2021; 9:686705. [PMID: 34790640 PMCID: PMC8592257 DOI: 10.3389/fpubh.2021.686705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 10/07/2021] [Indexed: 12/23/2022] Open
Abstract
The COVID-19 outbreak caused by the Severe Acute Respiratory Syndrome CoronaVirus type 2 (SARS-CoV-2) has spread across the world. However, our understanding of the public responses, in particular in adopting protective behaviors, has been limited. The current study aimed to determine the level of protective behaviors adopted by the residents in China and its association with their cultural attributes. A national cross-sectional online survey was conducted in mainland China from 4th to 13th August 2020. Protective behaviors were assessed as a summed score (ranging from 0 to 40) measured by ten items. The self-report tendency of study participants toward the four cultural attributes (individualism, egalitarianism, fatalism, hierarchy) was rated on a seven-point Likert scale. A total of 17651 respondents returned a valid questionnaire, representing 47.9% of those who accessed the online survey. Most (89.8%) respondents aged between 18 and 45 years in the age range of and 47.7% were male. High levels of protective behaviors (34.04 ± 5.78) were reported. The respondents had high scores in the cultural attributes of hierarchy (Median = 5) and egalitarianism (Median = 5), compared with low scores in individualism (Median = 1) and fatalism (Median = 1). High levels of protective behaviors were associated a higher tendency toward egalitarianism (AOR = 2.90, 95% CI 2.67–3.15) and hierarchy (AOR = 1.66, 95% CI 1.53–1.81) and a low tendency toward fatalism (AOR = 1.79, 95% CI 1.63–1.97) and individualism (AOR = 2.62, 95% CI 2.41–2.85). The cultural attributes explained 17.3% of the variations in the protective behavioral scores. In conclusion, the adoption of protective behaviors is associated a risk culture characterized by high levels of hierarchy and egalitarianism and low levels of individualism and fatalism. Government actions and communication strategies need to adapt to the cultural characteristics of their target audience.
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Affiliation(s)
- Xuejing Bi
- School of Health Management, Harbin Medical University, Harbin, China
| | - Qiao Zhang
- School of Health Management, Harbin Medical University, Harbin, China
| | - Kaisheng Fan
- School of Health Management, Harbin Medical University, Harbin, China
| | - SiYu Tang
- School of Health Management, Harbin Medical University, Harbin, China
| | - HanWen Guan
- School of Health Management, Harbin Medical University, Harbin, China
| | - XueQin Gao
- School of Health Management, Harbin Medical University, Harbin, China
| | - Yu Cui
- School of Health Management, Harbin Medical University, Harbin, China
| | - Yi Ma
- School of Health Management, Harbin Medical University, Harbin, China
| | - QunHong Wu
- School of Health Management, Harbin Medical University, Harbin, China
| | - YanHua Hao
- School of Health Management, Harbin Medical University, Harbin, China
| | - Ning Ning
- School of Health Management, Harbin Medical University, Harbin, China
| | - Chaojie Liu
- School of Psychology & Public Health, La Trobe University, Melbourne, VIC, Australia
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Hao YH, Luo SY, Tang XB. [The diagnosis value of real time fluorescence quantitative PCR for tuberculosis in paraffin embedded tissue]. Zhonghua Bing Li Xue Za Zhi 2020; 49:1068-1070. [PMID: 32992427 DOI: 10.3760/cma.j.cn112151-20200327-00263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Y H Hao
- Department of Pathology, Taihe Hospital, Hubei University of Medicine, Shiyan 442000, Hubei Province, China
| | - S Y Luo
- Department of Pathology, Taihe Hospital, Hubei University of Medicine, Shiyan 442000, Hubei Province, China
| | - X B Tang
- Department of Pathology, Taihe Hospital, Hubei University of Medicine, Shiyan 442000, Hubei Province, China
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Hao YH, Liu P, Tang XB. [Nodular fasciitis with USP6 gene rupture and deletion: report of a case]. Zhonghua Bing Li Xue Za Zhi 2020; 49:957-959. [PMID: 32892570 DOI: 10.3760/cma.j.cn112151-20191211-00794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Y H Hao
- Department of Pathology, Taihe Hospital, Hubei University of Medicine, Shiyan 442000, China
| | - P Liu
- Department of Pathology, Taihe Hospital, Hubei University of Medicine, Shiyan 442000, China
| | - X B Tang
- Department of Pathology, Taihe Hospital, Hubei University of Medicine, Shiyan 442000, China
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Tang XB, Hao YH, Yao L, Li D, Yuan LL, Shen X, Wang DZ, Liu P, Wang TY, Luo SY, Zhou ML. [Clinicopathological features of invasive micropapillary salivary duct carcinoma]. Zhonghua Bing Li Xue Za Zhi 2020; 49:479-481. [PMID: 32392934 DOI: 10.3760/cma.j.cn112151-20190925-00528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- X B Tang
- Department of Pathology, Taihe Hospital, Hubei University of Medicine,Shiyan 442000, China
| | - Y H Hao
- Department of Pathology, Taihe Hospital, Hubei University of Medicine,Shiyan 442000, China
| | - L Yao
- Department of Pathology, Taihe Hospital, Hubei University of Medicine,Shiyan 442000, China
| | - D Li
- Department of Pathology, Taihe Hospital, Hubei University of Medicine,Shiyan 442000, China
| | - L L Yuan
- Department of Pathology, Taihe Hospital, Hubei University of Medicine,Shiyan 442000, China
| | - X Shen
- Department of Pathology, Danjiangkou People's Hospital of Hubei Province, Danjiangkou 442700, China
| | - D Z Wang
- Department of Pathology, Taihe Hospital, Hubei University of Medicine,Shiyan 442000, China
| | - P Liu
- Department of Pathology, Taihe Hospital, Hubei University of Medicine,Shiyan 442000, China
| | - T Y Wang
- Department of Pathology, Taihe Hospital, Hubei University of Medicine,Shiyan 442000, China
| | - S Y Luo
- Department of Pathology, Taihe Hospital, Hubei University of Medicine,Shiyan 442000, China
| | - M L Zhou
- Department of Pathology, Taihe Hospital, Hubei University of Medicine,Shiyan 442000, China
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Zhang YS, Weng WY, Xie BC, Meng Y, Hao YH, Liang YM, Zhou ZK. Glucagon-like peptide-1 receptor agonists and fracture risk: a network meta-analysis of randomized clinical trials. Osteoporos Int 2018; 29:2639-2644. [PMID: 30083774 DOI: 10.1007/s00198-018-4649-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/19/2018] [Indexed: 02/08/2023]
Abstract
UNLABELLED Our network meta-analysis analyzed the effects of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) on fracture risk. By combining data from randomized controlled trials, we found that GLP-1 RAs were associated with a decreased bone fracture risk, and exenatide is the best option agent with regard to the risk of fracture. This study is registered with PROSPERO (CRD42018094433). INTRODUCTION Data on the effects of GLP-1 RAs on fracture risk are conflicted. This study aimed to analyze the available evidence on the effects of GLP-1 RAs on fracture risk in type 2 diabetes mellitus patients. METHODS Electronic databases were searched for relevant published articles, and unpublished studies presented at ClinicalTrials.gov were searched for relevant clinical data. All analyses were performed with STATA 12.0 and R software (Version 3.4.4). We estimated the risk ratio (RR) and 95% confidence interval (CI) by combining RRs for fracture effects of included trials. RESULTS There were 54 eligible random control trials (RCTs) with 49,602 participants, including 28,353 patients treated with GLP-1 RAs. Relative to placebo, exenatide (RR, 0.17; 95% CI 0.03-0.67) was associated with lowest risk of fracture among other GLP-1 RAs. Exenatide had the highest probability to be the safest option with regard to the risk of fracture (0.07 ‰), followed by dulaglutide (1.04%), liraglutide (1.39%), albiglutide (5.61%), lixisenatide (8.07%), and semaglutide (18.72%). A statistically significant inconsistency was observed in some comparisons. CONCLUSION The Bayesian network meta-analysis suggests that GLP-1 RAs were associated with a decreased bone fracture risk compared to users of placebo or other anti-hyperglycemic drugs in type 2 diabetes mellitus patients, and exenatide is the best option agent with regard to the risk of fracture.
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Affiliation(s)
- Y S Zhang
- Department of Pharmacy, Guangdong Medical University, No. 1, Xincheng Dadao, Songshan Lake Science and Technology Industry Park, Dongguan, 523808, China
| | - W Y Weng
- Department of Pharmacy, Guangdong Medical University, No. 1, Xincheng Dadao, Songshan Lake Science and Technology Industry Park, Dongguan, 523808, China
| | - B C Xie
- Department of Pharmacy, Guangdong Medical University, No. 1, Xincheng Dadao, Songshan Lake Science and Technology Industry Park, Dongguan, 523808, China
| | - Y Meng
- Department of Pharmacy, Guangdong Medical University, No. 1, Xincheng Dadao, Songshan Lake Science and Technology Industry Park, Dongguan, 523808, China
| | - Y H Hao
- Department of Pharmacy, Guangdong Medical University, No. 1, Xincheng Dadao, Songshan Lake Science and Technology Industry Park, Dongguan, 523808, China
| | - Y M Liang
- Department of Pharmacy, Guangdong Medical University, No. 1, Xincheng Dadao, Songshan Lake Science and Technology Industry Park, Dongguan, 523808, China
| | - Z K Zhou
- Department of Pharmacy, Guangdong Medical University, No. 1, Xincheng Dadao, Songshan Lake Science and Technology Industry Park, Dongguan, 523808, China.
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Hao YH, Chen XW, Wang L, Tang XB. [Detection of fusion gene transcript in formalin-fixed paraffin-embedded myxoid/round cell liposarcoma tissues by improved reverse transcription polymerase chain reaction]. Zhonghua Bing Li Xue Za Zhi 2017; 46:723-725. [PMID: 29050077 DOI: 10.3760/cma.j.issn.0529-5807.2017.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Han LY, Wu QH, Jiao ML, Hao YH, Liang LB, Gao LJ, Legge DG, Quan H, Zhao MM, Ning N, Kang Z, Sun H. Associations between single-nucleotide polymorphisms (+45T>G, +276G>T, -11377C>G, -11391G>A) of adiponectin gene and type 2 diabetes mellitus: a systematic review and meta-analysis. Diabetologia 2011; 54:2303-14. [PMID: 21638131 DOI: 10.1007/s00125-011-2202-9] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 04/27/2011] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS The associations between adiponectin polymorphisms and type 2 diabetes have been studied widely; however, results are inconsistent. METHODS We searched electronic literature databases and reference lists of relevant articles. A fixed or random effects model was used on the basis of heterogeneity. Sub-group and meta-regression analyses were conducted to explore the sources of heterogeneity. RESULTS There were no statistically significant associations between +45T>G (rs2241766), +276G>T (rs1501299), -11391G>A (rs17300539) and type 2 diabetes risk. However, for -11377C>G (rs266729), the pooled OR (95% CI) for G vs C allele was 1.07 (1.03-1.11, p = 0.001). Subgroup analysis by study design revealed that -11377C>G (rs266729) dominant model (CG+GG vs CC, p = 0.0008) and G vs C allele (p = 0.0004) might be associated with type 2 diabetes risk in population-based case-control studies. After stratification by ethnicity, we found that -11377C>G (rs266729) dominant model (CG+GG vs CC, p = 0.004) and G vs C allele (p = 0.001) might be associated with type 2 diabetes risk in white individuals. In individuals with a family history of diabetes, the presence of -11391G>A (rs17300539) dominant model (GA+AA vs GG) and A vs G allele might be associated with increased risk of type 2 diabetes. CONCLUSIONS/INTERPRETATION The presence of +45T>G (rs2241766), +276G>T (rs1501299) and -11391G>A (rs17300539) do not appear to influence the development of type 2 diabetes. However, G vs C allele of -11377C>G (rs266729) might be a risk factor for type 2 diabetes.
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Affiliation(s)
- L Y Han
- Department of Social Medicine, School of Public Health, Harbin Medical University, 157 Baojian Road, Harbin, Heilongjiang 150081, People's Republic of China
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Cheng MG, Hao YH, Cao JH, Liang T, Zhou KY, Ling GX. [Determination of the trace levels of urinary fibrinopeptides by high-performance capillary electrophoresis]. Nan Fang Yi Ke Da Xue Xue Bao 2008; 28:1005-1007. [PMID: 18583249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
OBJECTIVE To establish a high-performance capillary electrophoresis (HPCE)-based method for detection of trace amount of urinary fibrinopeptide A and B (FPA and FPB, respectively) as the specific molecular markers of thrombus formation in vivo. METHODS The HPCE system consisted of a 25 cm x 50 microm (inner diameter) coated capillary column, 0.1 mol/L phosphoric acid buffer (pH 2.5) and a UV-detector (wavelength at 190 nm). To improve the sensitivity and reproducibility, solid-phase extraction of FPA and FPB in the urine was performed using a Sep-pak C18 column, with a synthetical fibrinopeptide B-Tyr (FPB-Tyr) as the internal standard. RESULTS With this HPCE method, optimal separations of FPA, FPB and FPB-Tyr was achieved within 16 min, with the migration time of 7.28 min, 14.31 min and 15.22 min, respectively. The adjusted peak area ratios of FPA or FPB and the internal standard showed good linearity with the corresponding concentrations of FPA or FPB spiked in the urine(R>0.99). Under the above chromatography conditions, the minimum detection concentration of FPA and FPB in untreated urine was 30 microg/L and 40 microg/L, respectively, and the assay precision and recovery of FPA and FPB were acceptable. CONCLUSION The method we established is reliable and specific for separation and identification of fibrinopeptides and other bioactive peptides.
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Affiliation(s)
- Ming-Gang Cheng
- Shenzhen Baoan Hospital of Affiliated to Southern Medical University, Shenzhen 518101, China.
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Hao YH, Yong HY, Murphy CN, Wax D, Samuel M, Rieke A, Lai L, Liu Z, Durtschi DC, Welbern VR, Price EM, McAllister RM, Turk JR, Laughlin MH, Prather RS, Rucker EB. Production of endothelial nitric oxide synthase (eNOS) over-expressing piglets. Transgenic Res 2006; 15:739-50. [PMID: 17080303 DOI: 10.1007/s11248-006-9020-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2006] [Accepted: 06/20/2006] [Indexed: 10/24/2022]
Abstract
Vascular function, vascular structure, and homeostasis are thought to be regulated in part by nitric oxide (NO) released by endothelial cell nitric oxide synthase (eNOS), and NO released by eNOS plays an important role in modulating metabolism of skeletal and cardiac muscle in health and disease. The pig is an optimal model for human diseases because of the large number of important similarities between the genomic, metabolic and cardiovascular systems of pigs and humans. To gain a better understanding of cardiovascular regulation by eNOS we produced pigs carrying an endogenous eNOS gene driven by a Tie-2 promoter and tagged with a V5 His tag. Nuclear transfer was conducted to create these animals and the effects of two different oocyte activation treatments and two different culture systems were examined. Donor cells were electrically fused to the recipient oocytes. Electrical fusion/activation (1 mM calcium in mannitol: Treatment 1) and electrical fusion (0.1 mM calcium in mannitol)/chemical activation (200 microM Thimerosal for 10 min followed by 8 mM DTT for 30 min: Treatment 2) were used. Embryos were surgically transferred to the oviducts of gilts that exhibited estrus on the day of fusion or the day of transfer. Two cloned transgenic piglets were born from Treatment 1 and low oxygen, and another two from Treatment 2 and normal oxygen. PCR, RT-PCR, Western blotting and immunohistochemistry confirmed that the pigs were transgenic, made message, made the fusion protein and that the fusion protein localized to the endothelial cells of placental vasculature from the conceptuses as did the endogenous eNOS. Thus both activation conditions and culture systems are compatible with development to term. These pigs will serve as the founders for a colony of miniature pigs that will help to elucidate the function of eNOS in regulating muscle metabolism and the cardiorespiratory system.
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Affiliation(s)
- Y H Hao
- Division of Animal Sciences, University of Missouri-Columbia, Columbia, MO, USA
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Abstract
In vitro-hatched oncospheres of Taenia solium, prepared by the sodium hypochlorite method and adjusted to approximately 5 x 10(2)/2ml phosphate buffer saline, were injected intramuscularly or intravenously into normal Balb/c mice. When these mice were sacrificed 2 months later, all cysticerci were exclusively recovered in the lungs from the mice with intravenous inoculation, but not with intramuscular injection. A high infection rate of 76% was obtained and a total of 45 cysticerci were collected from 50 mice. Thirty-five cysticerci were mature and with normal appearance but the rest were either with abnormal appearance (4) or degenerated (6). These findings give strong evidence that T. solium oncospheres may migrate to the normal mouse lung through venous circulation and develop in this organ.
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Affiliation(s)
- Y J Liu
- College of Veterinary Medicine, Nanjing Agricultural University, Peoples Republic of China.
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Abstract
Normal human somatic cells can only divide for a limited number of times. This phenomenon has been regarded as a reflection of individual aging at the cellular level. Experimental evidences suggest that a cell's division potential is limited by the physical length of telomeres that gradually shorten through successive cell divisions. At present, it is not clear whether such a limit is imposed by the overall shortening of all telomeres or the shortening of certain critical ones. Computer simulations have suggested that among the 92 telomeres in human cells, two specific telomeres might be preferentially involved in such process. Recent experiment has shown that in a culture of male human cells, the length of the telomeres at the chromosome X(p) is reserved over the later passages during clonal proliferation. This unique feature, if can be further confirmed in other cells, implies a critical role of the telomeres at X(p) in limiting the proliferation capacity of human cells.
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Affiliation(s)
- Y H Hao
- College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China
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Abstract
The influence of cholesterol on the sphingomyelin (SM)/dioleoylphosphatidylcholine (DOPC) binary system was investigated in various respects. Electron spin resonance (ESR) measurements reveal that the order parameter of 5DS (5-doxyl stearic acid) in SM/DOPC bilayers increases notably when the concentration of cholesterol is over 30 mol%. Membrane potential measurements indicate that the K+ permeability of the SM/DOPC bilayer decreases steeply at 40 mol% cholesterol concentration. Both these experiments suggest that cholesterol reduces the motion amplitude of hydrocarbon chains abruptly above 30 mol%. In contrast to the ordering effects on the hydrocarbon chains, (31)P-NMR results indicate that cholesterol slightly increases the motion of phosphate groups of the lipids. (31)P-NMR also raises the possibility of domain formation in the presence of cholesterol. Fluorescence-quenching experiments verified that solid domains appear in the binary system when cholesterol is present, and percolation threshold occurs at 50 mol% cholesterol concentration. The solid domains bear the properties of liquid ordered phase, which is the basic structure of caveolae and functional rafts. So this work provides an artificial model for the study of rafts and caveolae on biological membranes.
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Affiliation(s)
- Y H Hao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing 100101, China
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Lu JZ, Hao YH, Chen JW. Effect of cholesterol on the formation of an interdigitated gel phase in lysophosphatidylcholine and phosphatidylcholine binary mixtures. J Biochem 2001; 129:891-8. [PMID: 11388903 DOI: 10.1093/oxfordjournals.jbchem.a002934] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We previously reported that 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) forms an interdigitated gel phase in the presence of 1-palmitoyl-sn-glycero-3-phosphocholine (16:0LPC) at concentrations below 30 mol%. In the present investigation, fluorescent probe 1,6-diphenyl-1,3,5-hexatriene (DPH), X-ray diffraction, and differential scanning calorimetry (DSC) were used to investigate the effect of cholesterol on the phase behavior of 16:0LPC/DPPC binary mixtures. At 25 degrees C, 30 mol% 16:0LPC significantly decreases the DPH fluorescence intensity during the transition of DPPC from the L(beta') phase to the L(betaI) phase. However, the addition of cholesterol to 16:0LPC/DPPC mixtures results in a substantial increase in fluorescence intensity. The changes in DPH fluorescence intensity reflect the probe's redistribution from an orientation parallel to the acyl chain to the center of the bilayer, suggesting a bilayer structure transition from interdigitation to noninterdigitation. The normal repeat period of small angle X-ray diffraction patterns can be restored and a reflection appears at 0.42 nm with a broad shoulder around 0.41 nm in wide angle X-ray diffraction patterns when 10 mol% cholesterol is incorporated into 30 mol% 16:0LPC/DPPC vesicles, indicating that the mixtures are in the gel phase (L(beta')). Moreover, DSC results demonstrate that 10 mol% cholesterol is sufficient to significantly decrease the main enthalpy, cooperativity and lipid chain melting of 30 mol% 16:0LPC/DPPC binary mixtures, which are L(betaI), indicating that the transition of the interdigitated phase is more sensitive to cholesterol than that of the noninterdigitated phase. Our data imply that the interdigitated gel phase induced by 16:0LPC is prevented in the presence of 10 mol% cholesterol, but unlike ethanol, an increasing concentration of 16:0LPC is not able to restore the interdigitation structure of the lipid mixtures.
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Affiliation(s)
- J Z Lu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing 100101, China
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Abstract
The effects of phase transition from normal to interdigitated lipid bilayer on the function and structure of membrane proteins were studied using linear gramicidin (gramicidin A) as a model. Interdigitated bilayer structure of dipalmitoylphosphatidylglycerol (DPPG) liposomes that was induced by atropine could not be changed notably by intercalating of gramicidin. The K+ transportation of gramicidin in both normal and interdigitated bilayer was assayed by measuring the membrane potential. Results showed that gramicidin in interdigitated bilayer exhibited lower transport capability. Intrinsic fluorescence spectrum of gramicidin in interdigitated bilayer blue-shifted 2.8 nm from the spectrum in normal bilayer, which means that interdigitation provides a more hydrophobic environment for gramicidin. Circular dichroism measurement results indicated that the conformation of gramicidin in interdigitated bilayer is not the typical beta6.3 helix as in the normal bilayer. The results suggested that the interdigitated lipid bilayer might largely affect the structure and function of membrane proteins.
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Affiliation(s)
- Y H Hao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing, People's Republic of China
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Abstract
X-ray diffraction and fluorescence methods have been carried out to examine the effects of a drug, atropine, on the structure of model membranes: dipalmitoylphosphatidylglycerol(DPPG) multilamella vesicles(MLVs). A structural analysis by small angle x-ray diffraction shows that, with incorporation of atropine, the lamella repeating period of DPPG MLV is decreased from 5.89 nm to 4.52 nm. Using fluorescence probe 1,6-diphenyl-1,3,5-hexatriene(DPH) we find that the fluorescence intensity of DPH reduces largely at a narrow scope of atropine concentration. The experiments of fluorescence polarization of n-(9-anthroyloxyl)-stearic acid (nAS) and 16-(9-anthroyloxyl)-palmiticacid (16AP) discover that the normal polarization gradient almost disappears in DPPG/atropine system. By colligating the above results, we can draw a conclusion that atropine induces the transition from non-interdigitated to interdigitated stricture of DPPG vesicles in gel phase, which provides a sound model of drug-lipid interaction.
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Affiliation(s)
- Y H Hao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Academy Sinica, Beijing, China
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