1.Enhancement of the mechanical and biological properties of a biomembrane for tissue engineering the ocular surface.
Xiao ZHU ; Roger W BEUERMAN ; Mary B E CHAN-PARK ; Zhiyuan CHENG ; Leonard P K ANG ; Donald T H TAN
Annals of the Academy of Medicine, Singapore 2006;35(3):210-214
<b>INTRODUCTIONb>In this study, we have developed and optimised a novel gelatin-chitosan (GC) substrate for use as a cellular carrier for tissue-engineered conjunctival epithelium.
<b>MATERIALS AND METHODSb>The substrate was fabricated by casting and the mechanical properties of the substrate, including tensile strength and elongation, were measured. Using the MTT, cell proliferation assay with rabbit conjunctival fibroblasts, we optimised the G:C ratio to enhance cytocompatibility. Rabbit conjunctival epithelial cells were immunostained using monoclonal antibodies for keratin 4 and pancytokeratin to investigate the biological effects of the GC substrate on the proliferation and differentiation of epithelial cells.
<b>RESULTSb>We found that increasing the amount of gelatin resulted in an increase in elasticity (from 1:9 to 1:1 ratio), reaching a maximum (101.89% +/- 7.13%) at a ratio of 1:1. The MTT assay showed that the proliferation of conjunctival fibroblasts significantly increased from 0.068 +/- 0.017 to 0.177 +/- 0.011 (P = 0.014) as the gelatin was increased from 20% (1:4) to 50% (1:1). Additional studies using tissue-cultured conjunctiva explants showed that these explants grew well on the substrate, forming a multilayered epithelium. Cell morphology on this substrate was similar to that of cells grown on culture dishes alone. Positive staining of keratin 4 and pancytokeratin indicated that the substrate supported normal differentiation of conjunctival epithelial cells.
<b>CONCLUSIONb>By enhancing the proportion of gelatin, both the mechanical and biological properties of the chitosan substrate were improved. The results also suggest that this GC biomembrane may be a useful candidate for reconstructive tissue engineering of the conjunctiva.
Animals ; Biocompatible Materials ; Cell Proliferation ; Cells, Cultured ; Chitosan ; Conjunctiva ; cytology ; metabolism ; physiology ; Elasticity ; Epithelium ; physiology ; Gelatin ; Keratins ; metabolism ; Rabbits ; Tensile Strength ; Tissue Engineering
2.Intermuscular Adipose Tissue Content and Intramyocellular Lipid Fatty Acid Saturation Are Associated with Glucose Homeostasis in Middle-Aged and Older Adults.
Jung Eun KIM ; Keagan DUNVILLE ; Junjie LI ; Ji Xin CHENG ; Travis B CONLEY ; Cortni S COUTURE ; Wayne W CAMPBELL
Endocrinology and Metabolism 2017;32(2):257-264
BACKGROUND: Insulin resistance is associated with the higher content of intermuscular adipose tissue (IMAT) and the saturation of intramyocellular lipid (IMCL), but a paucity of data exist in humans. This study examined associations among IMAT content, IMCL saturation, and fasting glucose concentration in middle-aged and older adults with overweight or obesity. METHODS: Seventy-five subjects (26 males, 49 females) were recruited and thigh muscle and IMAT were assessed using magnetic resonance imaging. Vastus lateralis tissue was acquired from a subset of nine subjects and IMCL content and saturation were assessed using nonlinear dual complex microscopy. RESULTS: The characteristics of the 75 subjects were as follows: age 59±11 years, body mass index 30±5 kg/m², fasting glucose concentration 5.2±0.5 mmol/L, fasting insulin concentration 12.2±7.3 µU/mL, fasting homeostatic model assessment of insulin resistance (HOMA-IR) 2.9±2.0 (mean±SD). IMAT to muscle tissue (MT) volume ratio was positively associated with the saturated fatty acid to unsaturated fatty acid ratio in IMCL. IMAT:MT was positively associated with fasting glucose concentration and HOMA-IR. IMCL saturation was positively associated with fasting glucose concentration while muscle cell area, IMCL area, and % IMCL in muscle cell were not associated with fasting glucose concentration. CONCLUSION: These results indicate that higher intermuscular fat content and IMCL saturation may impact fasting glucose concentration in middle-aged and older adults with overweight or obesity. The centralization of adipose tissue in the appendicular region of the body may promote insulin resistance.
Adipose Tissue*
;
Adult*
;
Body Mass Index
;
Fasting
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Glucose*
;
Homeostasis*
;
Humans
;
Insulin
;
Insulin Resistance
;
Magnetic Resonance Imaging
;
Male
;
Microscopy
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Muscle Cells
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Obesity
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Overweight
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Quadriceps Muscle
;
Thigh
3.The use of n-butyl-2 cyanoacrylate as an embolic agent in the minimally invasive treatment of renal arteriovenous malformations.
Pei Ghim POH ; Bien Soo TAN ; Seng Choe THAM ; Kiang Hiong TAY ; Austin M M HTOO ; Michael B K LIN ; Christopher W S CHENG ; Tsung Wen CHONG ; Keong Tat FOO ; Winston E H LIM
Annals of the Academy of Medicine, Singapore 2013;42(4):207-209
Adult
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Arteriovenous Malformations
;
therapy
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Embolization, Therapeutic
;
methods
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Enbucrilate
;
therapeutic use
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Female
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Humans
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Kidney
;
blood supply
;
Male
;
Middle Aged
5.Percutaneous transluminal angioplasty of transplant renal artery stenosis.
Lee Lian CHEW ; Bien Soo TAN ; Krishna KUMAR ; Maung Myint HTOO ; Kok Seng WONG ; Christopher W S CHENG ; Terence K B TEO ; Farah Gillani IRANI ; Hui Lin CHOONG ; Kiang Hiong TAY
Annals of the Academy of Medicine, Singapore 2014;43(1):39-43
<b>INTRODUCTIONb>This study aimed to assess the outcome of percutaneous transluminal angioplasty (PTA) as the primary treatment for transplant renal artery stenosis (TxRAS).
<b>MATERIALS AND METHODSb>A retrospective review of PTA of TxRAS from April 1999 to December 2008 was performed. Twenty-seven patients (17 males (M):10 females (F)) with the mean age of 49.5 years underwent PTA of TxRAS in the review period. Indications for PTA were suboptimal control of hypertension (n=12), impaired renal function (n=6) and both suboptimal control of hypertension and impaired renal function (n=9). All patients had doppler ultrasound scans prior to their PTA. In addition, 5 of these patients had computed tomography angiography (CTA) and another 7 had magnetic resonance angiography (MRA) evaluation. Mean follow-up period was 57.0 months (range, 7 to 108 months).
<b>RESULTSb>The stenotic lesions were located proximal to the anastomosis (n=2), at the anastomosis (n=15), and distal to the anastomosis (n=14). Technical success rate was 96.3%. One case was complicated by extensive dissection during PTA, resulting in subsequent graft failure. The overall clinical success rate was 76.9%. Seven out of 26 patients had restenoses (26.9% of cases). These were detected at a mean of 14.3 months post angioplasty (range, 5 to 38 months). All 7 patients underwent a second PTA successfully. Three of these patients required more than 1 repeat PTA.
<b>CONCLUSIONb>PTA is safe and effective in the management of symptomatic TxRAS and should be the primary treatment of choice. Close surveillance for restenosis is required and when diagnosed, re-angioplasty can be performed.
Adult ; Angioplasty ; Female ; Humans ; Kidney Transplantation ; Male ; Middle Aged ; Postoperative Complications ; surgery ; Renal Artery Obstruction ; surgery ; Retrospective Studies ; Time Factors
6.Understanding XDP through imaging,pathology,and genetics.
Pasco Paul Matthew D ; Ison Claro V ; Pasco Paul Matthew D ; Muñoz Edwin L ; Magpusao Nelma S ; Cheng Anthony E ; Tan Kenneth T ; Lo Raymundo W ; Teleg Rosalia A ; Dantes Marita B ; Borres Ruth ; Maranon Elma ; Demaisip Cynthia ; Reyes Marita V.T. ; Lee Lillian V
Philippine Journal of Neurology 2012;16(1):73-78
The X-linked dystonia-parkinsonism (XDP) is a severe progressive, adult-onset X-linked endemic disorder in Filipinos, which is characterized by dystonic movements that start in the third of fourth decade, and replaced by parkinsonism beyond the 10th year of illness. Understanding the pathophysiology of XDP and development of rational therapies will depend on observations from imaging pathological and genetic studies. In this paper we summarize the results of these studies on patients with XDP. The cranial magnetic resonance imaging shows hy-perintense putaminal rim in both dystonic and parkinsonian stages, and atrophy of the caudate head or putamen in the parkinsonian stage. Neuropathological findings show atrophy of the caudate nucleus and putamen, with mild to severe neuronal loss and gliosis. In the neostriatum, the dystonic phase of XDP shows the involvement of striosomes and matrix sparing, while the later, i.e., p[arkinsonian phase, shows matrix involvement as well. In the dystonic phase, the loss of striosomal inhibitory projections lead to disinhibition of nigral dopaminergic neurons, perhaps resulting in a hyperkinetic state; while in the parkinsonian phase, severe and critical reduction of matrix-based projection may result in extranigral parkinsonism. Genetic sequencing of the XDP critical region in Xq13.1 has revealed an SVA retronsposon insertion in an intron of TAF1. This may reduce neuron-specific expression of the TAF1 isoform in the caudade nucleus, and subsequently interfere with the transcription of many neuronal genes, including DRD2. Findings from imaging, pahtology, and genetics studies are gradually shedding light on the pathophysiology of XDP, which hopefully will lead to mare rational and directed therapies.
Human ; Adult ; Atrophy ; Caudate Nucleus ; Dopaminergic Neurons ; Dystonic Disorders ; Genetic Diseases, X-linked ; Gliosis ; Introns ; Parkinsonian Disorders ; Protein Isoforms ; Putamen
8.Characteristic and dynamic of HIV-1 subtype distribution in men who have sex with men in Guangzhou, 2008-2015.
Z G HAN ; Y L ZHANG ; H WU ; W B CHENG ; C Y LIANG ; F ZHONG ; K GAO ; H F XU
Chinese Journal of Epidemiology 2018;39(1):67-71
<b>Objective:b> To understand the characteristics and dynamic of HIV-1 subtype distribution in men who have sex with men (MSM) in Guangzhou between 2008 and 2015. <b>Methods:b> HIV-1 RNAs were extracted from serum samples of the individuals newly diagnosed with HIV-1 infection among MSM living in Guangzhou between 2008 and 2015. The pol gene segments of HIV-1 genome from these RNA samples were amplified by nested reverse transcription polymerase chain reaction (nested-PCR) and were sequenced. Subsequently, the phylogenetic tree was reconstructed using pol sequences of samples and references together and the subtype of HIV-1 was determined. The distributions of HIV-1 subtypes detected in MSM with different demographic characteristics in different years were compared. <b>Results:b> A total of 2 210 pol gene segments were successfully obtained from 2 473 serum samples of the MSM. The average age of 2 210 MSM was 30.19 years with standard deviation of 8.22 years, the unmarried MSM and those in Han ethnic group accounted for 73.39% and 90.81%, respectively. The proportion of subtype CRF07_BC (38.10%) was highest, followed by CRF01_AE (34.84%), CRF55_01B (14.62%), B (6.06%), URFs (3.58%), CRF59_01B (2.17%) and other subtypes (0.63%). The annual proportions of subtype B (P=0.000, 99%CI:0.000-0.000), CRF07_BC (χ(2)=14.965, P=0.036), CRF55_01B (χ(2)=18.161, P=0.011) and URFs (P=0.001, 99% CI: 0.000-0.001) were significantly different. The proportion of subtype B showed a gradual decrease from 14.08% to 4.33% (P=0.000, 99%CI: 0.000-0.000), while the proportion of URFs rapidly increased from 0% to 6.40% (P=0.000, 99% CI: 0.000-0.000). The rate of URFs was significantly higher in farmers and migrant workers than in other groups (P=0.017, 99%CI: 0.014- 0.020) and the rate of URFs was higher in individuals who had multi sexual partners (χ(2)=5.733, P=0.017). <b>Conclusions:b> CRF07_BC and CRF01_AE were the predominant HIV-1 subtypes and multiple subtypes co-circulated among MSM in Guangzhou between 2008 and 2015. The recombinations of HIV-1 continue to occur in MSM. Strengthening behavioral intervention for farmers, migrant workers and individuals who have multi sexual partners has the important epidemiological significance against the emerging and circulating of the novel recombinant virus among MSM in Guangzhou.
China/epidemiology*
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Genes, pol
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Genotype
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HIV Infections/virology*
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HIV Seropositivity/genetics*
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HIV-1/isolation & purification*
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Homosexuality, Male
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Humans
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Male
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Phylogeny
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Polymerase Chain Reaction
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RNA, Viral/blood*
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Sexual Behavior
9.Characteristics and influencing factors regarding social relations among men who have sex with men.
J YANG ; H F XU ; W B CHENG ; Y Z GU ; P XU ; Q Y YU ; P LYU
Chinese Journal of Epidemiology 2018;39(4):478-482
<b>Objective:b> To study the characteristics of social relations and relative factors among MSM in Guangzhou. <b>Methods:b> Data was collected through a cross-sectional study in Guangzhou from November 2016 to May 2017. Sample size was estimated and participants were recruited from the voluntary counseling and testing services (VCT) which were set for MSM population, by nongovernmental organizations (NGOs) and the Centers for Disease Control and Prevention (CDC). Social ties and demographic characteristics of the respondents and their sexual partners were analyzed through both Chi square test and generalized estimating equations (GEE). <b>Results:b> A total of 1 073 MSM, together with their nominated 4 301 partners were successfully recruited and involved in this study. Age (OR=1.2, P=0.01) and non-internet based intercourse (OR=1.65, P<0.01) were easy to form close relation with strong ties. Compared with MSM traditional venues (chess and cards room, tea room bathhouse, club), general public venue (bars, KTV, parks, shopping malls, schools, restaurants) (OR=1.46-3.12, P<0.01) showed close relation with strong ties. Our finding showed that MSM at the age of 18-25 preferred to build weak ties with the older MSM, while the 26-30-year-olds and 31-40-year-olds prefer to establish weak ties with younger partners but the 41-50-year-olds preferred to develop weak ties with one that were ten years younger. <b>Conclusions:b> Clusters were noticed in the MSM populations when grouping and making friends with ones at different age. Characteristics regarding the relationship between sexual partners in choosing venues and ways of dating were different. Targeted intervention programs need to be explored innovatively.
Coitus
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Cross-Sectional Studies
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Homosexuality, Male/psychology*
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Humans
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Interpersonal Relations
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Male
;
Middle Aged
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Recreation
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Risk-Taking
;
Schools
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Sexual Behavior
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Sexual Partners
;
Social Behavior
;
Surveys and Questionnaires
10.New psychoactive substances abuse among patients with access to methadone maintenance treatment in Jiangsu province: a case-control study.
Z CHENG ; G H CHEN ; M M DAI ; W LUO ; P LYU ; X B CAO
Chinese Journal of Epidemiology 2018;39(5):625-630
<b>Objective:b> To explore the reasons and factors associated with new psychoactive substances abuse among patients with access to methadone maintenance treatment (MMT). <b>Methods:b> A well-developed questionnaire and urine tests were used to collect information about demographic characteristics, condition of MMT and drug abuse, family and social support of MMT clients. A 1∶1 matched case-control study was conducted, and conditional logistic regression model was used to identify factors associated with new psychoactive substances abuse. <b>Results:b> A total of 212 (106 pairs) clients receiving MMT were recruited, and most of them were males (78.3%, 166/212), married or cohabitant (48.6%, 103/212) and unemployed (63.2%, 134/212). The average age of the clients was (45.1±7.2) years. The main types of abused new psychoactive substances were benzodiazepine (62.3%, 66/106) and methamphetamine (39.6%, 42/106). The proportion of abusing multi new psychoactive substances was 8.5% (9/106). Results from multivariate conditional logistic regression analysis indicated that using opioid drug during the past 6 months of MMT treatment might increase the risk of abusing new psychoactive substances (OR=3.25, 95%CI: 1.35-7.79), benzodiazepine (OR=3.25, 95%CI: 1.11- 9.47) and methamphetamine (OR=13.31, 95%CI: 1.12-158.01). Moreover, MMT for more than9 years reduced the risk of abuse of new psychoactive substances (OR=0.03, 95%CI: 0.01-0.21), benzodiazepine (OR=0.02, 95%CI: 0.00-0.36) and methamphetamine (OR=0.02, 95%CI: 0.00-0.69). <b>Conclusion:b> Less new psychoactive substances abuse might be associated with longer duration of MMT treatment. And inappropriate support from family and friends might increase the risk of abusing new psychoactive substances in MMT clients, especially in clients who used opioid.
Adult
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Case-Control Studies
;
China/epidemiology*
;
Drug Users/statistics & numerical data*
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Humans
;
Logistic Models
;
Male
;
Methadone/therapeutic use*
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Methamphetamine
;
Middle Aged
;
Opiate Substitution Treatment
;
Prevalence
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Psychotropic Drugs/adverse effects*
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Substance Abuse Detection/statistics & numerical data*
;
Substance Abuse Treatment Centers
;
Substance-Related Disorders/epidemiology*
;
Surveys and Questionnaires