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Licht P, McCreery BR, Barnes R, Pang R. Seasonal and stress related changes in plasma gonadotropins, sex steroids, and corticosterone in the bullfrog, Rana catesbeiana. Gen Comp Endocrinol 1983; 50:124-45. [PMID: 6406295 DOI: 10.1016/0016-6480(83)90249-6] [Citation(s) in RCA: 256] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Studies of seasonal gonadal cycles combined with direct measurements of plasma levels of the two gonadotropins (FSH and LH), several gonadal steroids (estrogen, E; progesterone, P; testosterone, T; and 5 alpha-dihydrotestosterone, DHT), and the interrenal steroid corticosterone (B) were made in male and female bullfrogs in central California over a 5-year period (between 1976 and 1981). During the course of these studies, we discovered that levels of plasma gonadotropins and steroids are highly labile and particularly sensitive to the effects of captivity, especially in males. In animals captured and sampled repeatedly in the field over a 3-day period, hormone levels remained constant, but if held in collecting sacks, gonadotropin and gonadal steroids began to drop within 2--4 hr and usually reached "baseline" levels within 20 hr. This effect was apparent in all seasons, except occasionally in early spring when hormone levels dropped by only about half. Hormone levels were also generally depressed by the time commercially collected frogs reached local supply houses. Plasma B increased within 30 min of capture and remained high for days in captive animals. Blood samples taken from several hundred animals at the time of capture reveal pronounced seasonal cycles in all hormones measured. These changes are discussed in connection with other gross changes in gonadal condition and with regard to possible interactions among gonadotropins and steroids. Both sexes show a general elevation of hormone levels in spring and early summer, but the sexes differ somewhat both in timing and in magnitude of the changes, as well as in the nature of the dominant steroids. Pronounced "surges" in gonadotropins are evident around the time of gamate release in bot sexes, but the temporal pattern of these surges is not the same for ovulation and spermiation; an elevation in plasma P is associated with the periovulatory surge in gonadotropins. Results were not entirely consistent with expectation of pituitary--gonadal relationships. Levels of plasma gonadotropins and steroids did not show the reciprocal relationship expected from a simple negative feed-back between gonadal and pituitary secretion, nor did changes in gonadotropins and gonadal activities show the consistent positive correlation expected from a direct dependence of gonadal function on circulating gonadotropins. In females, plasma T, but not E, correlated with ovarian growth. Plasma T in females reached much higher levels than in males, but DHT was higher in males. Androgens were generally elevated during the period of sexual activity in males, but absolute levels did not correlate well with individual differences in sexual behavior. Thus, seasonal changes in testicular and ovarian activities cannot be accounted for solely by seasonal cycles in circulating gonadotropin levels.
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Comparative Study |
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Papageorghiou AT, Kennedy SH, Salomon LJ, Ohuma EO, Cheikh Ismail L, Barros FC, Lambert A, Carvalho M, Jaffer YA, Bertino E, Gravett MG, Altman DG, Purwar M, Noble JA, Pang R, Victora CG, Bhutta ZA, Villar J. International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2014; 44:641-8. [PMID: 25044000 PMCID: PMC4286014 DOI: 10.1002/uog.13448] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
OBJECTIVES There are no international standards for relating fetal crown-rump length (CRL) to gestational age (GA), and most existing charts have considerable methodological limitations. The INTERGROWTH-21(st) Project aimed to produce the first international standards for early fetal size and ultrasound dating of pregnancy based on CRL measurement. METHODS Urban areas in eight geographically diverse countries that met strict eligibility criteria were selected for the prospective, population-based recruitment, between 9 + 0 and 13 + 6 weeks' gestation, of healthy well-nourished women with singleton pregnancies at low risk of fetal growth impairment. GA was calculated on the basis of a certain last menstrual period, regular menstrual cycle and lack of hormonal medication or breastfeeding in the preceding 2 months. CRL was measured using strict protocols and quality-control measures. All women were followed up throughout pregnancy until delivery and hospital discharge. Cases of neonatal and fetal death, severe pregnancy complications and congenital abnormalities were excluded from the study. RESULTS A total of 4607 women were enrolled in the Fetal Growth Longitudinal Study, one of the three main components of the INTERGROWTH-21(st) Project, of whom 4321 had a live singleton birth in the absence of severe maternal conditions or congenital abnormalities detected by ultrasound or at birth. The CRL was measured in 56 women at < 9 + 0 weeks' gestation; these were excluded, resulting in 4265 women who contributed data to the final analysis. The mean CRL and SD increased with GA almost linearly, and their relationship to GA is given by the following two equations (in which GA is in days and CRL in mm): mean CRL = -50.6562 + (0.815118 × GA) + (0.00535302 × GA(2) ); and SD of CRL = -2.21626 + (0.0984894 × GA). GA estimation is carried out according to the two equations: GA = 40.9041 + (3.21585 × CRL(0.5) ) + (0.348956 × CRL); and SD of GA = 2.39102 + (0.0193474 × CRL). CONCLUSIONS We have produced international prescriptive standards for early fetal linear size and ultrasound dating of pregnancy in the first trimester that can be used throughout the world.
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Clinical Trial |
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Chim CS, Pang R, Fung TK, Choi CL, Liang R. Epigenetic dysregulation of Wnt signaling pathway in multiple myeloma. Leukemia 2007; 21:2527-36. [PMID: 17882284 DOI: 10.1038/sj.leu.2404939] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Wnt signaling has recently been implicated in carcinogenesis. We studied the activity of Wnt signaling and the methylation status of WIF1, DKK3, APC, SFRP1, SFRP2, SFRP4 and SFRP5 by methylation-specific PCR in myeloma cell lines and primary myeloma samples. Of the four cell lines, Wnt signaling was constitutively activated in LP1 and WL2, correlating with hypermethylation and hence silencing. Moreover, 5-aza-2'-deoxycytidine treatment of these two cell lines showed progressive demethylation of methylated Wnt inhibitors, re-expression of transcripts and downregulation of Wnt signaling. In both LP1 and WL2 cells, multiple Wnts and Fzs were simultaneously expressed. Treatment of WL2, in which SFRP1 was completely methylated, with recombinant secreted Frizzled-related protein 1 (SFRP1) induced downregulation of Wnt signaling and inhibition of proliferation. In primary myeloma samples, 42% patients had methylation of at least one of these seven genes, of which 61.9% had > or = 2 genes methylated. In conclusion, Wnt signaling is constitutively activated in myeloma, associated with methylation silencing of one or multiple soluble Wnt antagonists. An autocrine loop regulating Wnt signaling was demonstrated in the myeloma plasma cells, in which cellular proliferation was efficiently inhibited by recombinant SFRP1. Methylation study of a panel of genes, regulating a cellular pathway instead of isolated genes, is important.
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Journal Article |
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Hirst JE, Villar J, Victora CG, Papageorghiou AT, Finkton D, Barros FC, Gravett MG, Giuliani F, Purwar M, Frederick IO, Pang R, Cheikh Ismail L, Lambert A, Stones W, Jaffer YA, Altman DG, Noble JA, Ohuma EO, Kennedy SH, Bhutta ZA. The antepartum stillbirth syndrome: risk factors and pregnancy conditions identified from the INTERGROWTH-21 st Project. BJOG 2016; 125:1145-1153. [PMID: 28029221 PMCID: PMC6055673 DOI: 10.1111/1471-0528.14463] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2016] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To identify risk factors for antepartum stillbirth, including fetal growth restriction, among women with well-dated pregnancies and access to antenatal care. DESIGN Population-based, prospective, observational study. SETTING Eight international urban populations. POPULATION Pregnant women and their babies enrolled in the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. METHODS Cox proportional hazard models were used to compare risks among antepartum stillborn and liveborn babies. MAIN OUTCOME MEASURES Antepartum stillbirth was defined as any fetal death after 16 weeks' gestation before the onset of labour. RESULTS Of 60 121 babies, 553 were stillborn (9.2 per 1000 births), of which 445 were antepartum deaths (7.4 per 1000 births). After adjustment for site, risk factors were low socio-economic status, hazard ratio (HR): 1.6 (95% CI, 1.2-2.1); single marital status, HR 2.0 (95% CI, 1.4-2.8); age ≥40 years, HR 2.2 (95% CI, 1.4-3.7); essential hypertension, HR 4.0 (95% CI, 2.7-5.9); HIV/AIDS, HR 4.3 (95% CI, 2.0-9.1); pre-eclampsia, HR 1.6 (95% CI, 1.1-3.8); multiple pregnancy, HR 3.3 (95% CI, 2.0-5.6); and antepartum haemorrhage, HR 3.3 (95% CI, 2.5-4.5). Birth weight <3rd centile was associated with antepartum stillbirth [HR, 4.6 (95% CI, 3.4-6.2)]. The greatest risk was seen in babies not suspected to have been growth restricted antenatally, with an HR of 5.0 (95% CI, 3.6-7.0). The population-attributable risk of antepartum death associated with small-for-gestational-age neonates diagnosed at birth was 11%. CONCLUSIONS Antepartum stillbirth is a complex syndrome associated with several risk factors. Although small babies are at higher risk, current growth restriction detection strategies only modestly reduced the rate of stillbirth. TWEETABLE ABSTRACT International stillbirth study finds individual risks poor predictors of death but combinations promising.
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Observational Study |
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Yau T, Wong H, Chan P, Yao TJ, Pang R, Cheung TT, Fan ST, Poon RT. Phase II study of bevacizumab and erlotinib in the treatment of advanced hepatocellular carcinoma patients with sorafenib-refractory disease. Invest New Drugs 2012; 30:2384-90. [PMID: 22402942 PMCID: PMC3484314 DOI: 10.1007/s10637-012-9808-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Accepted: 02/26/2012] [Indexed: 12/14/2022]
Abstract
Background The combination of bevacizumab (B) and erlotinib (E) has shown promising clinical outcomes as the first-line treatment of advanced HCC patients. We aimed to evaluate the efficacy and safety of using combination of B + E in treating advanced HCC patients who had failed prior sorafenib treatment. Methods Eligible advanced HCC patients with documented radiological evidence of disease progression with sorafenib treatment were recruited. All patients received bevacizumab(B) at 10 mg/kg every 2 weeks with erlotinib(E) at 150 mg daily for a maximum of 6 cycles. Response assessments using both RECIST and modified RECIST criteria were performed after every 6 weeks. The primary endpoint was clinical benefit (CB) rate and a Simon two-stage design was employed. Results The trial was halted in the first stage according to the pre-set statistical criteria with 10 patients recruited. The median age was 47 years (range, 28–61) and all patients were in ECOG performance status 1. Eighty percent of patients were chronic hepatitis B carriers and all patients had Child A cirrhosis. Among these 10 patients, none of the enrolled patients achieved response or stable disease. The median time-to-progression was 1.81 months (95 % confidence interval [C.I.], 1.08–1.74 months) and overall survival was 4.37 months (95 % C.I., 1.08–11.66 months). Rash (70 %), diarrhea (50 %) and malaise (40 %) were the most commonly encountered toxicities. Conclusion The combination of B + E was well tolerated but had no activity in an unselected sorafenib-refractory advanced HCC population. Condensed abstract The combination of bevacizumab and erlotinib had no clinical activity in sorafenib-refractory HCC population.
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Research Support, Non-U.S. Gov't |
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53 |
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Cavallaro A, Ash ST, Napolitano R, Wanyonyi S, Ohuma EO, Molloholli M, Sande J, Sarris I, Ioannou C, Norris T, Donadono V, Carvalho M, Purwar M, Barros FC, Jaffer YA, Bertino E, Pang R, Gravett MG, Salomon LJ, Noble JA, Altman DG, Papageorghiou AT. Quality control of ultrasound for fetal biometry: results from the INTERGROWTH-21 st Project. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2018; 52:332-339. [PMID: 28718938 DOI: 10.1002/uog.18811] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 07/01/2017] [Accepted: 07/05/2017] [Indexed: 06/07/2023]
Abstract
OBJECTIVE To assess a comprehensive package of ultrasound quality control in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project, a large multicenter study of fetal growth. METHODS Quality control (QC) measures were performed for 20 313 ultrasound scan images obtained prospectively from 4321 fetuses at 14-41 weeks' gestation in eight geographical locations. At the time of each ultrasound examination, three fetal biometric variables (head circumference (HC), abdominal circumference (AC) and femur length (FL)) were measured in triplicate on separately generated images. All measurements were taken in a blinded fashion. QC had two elements: (1) qualitative QC: visual assessment by sonographers at each study site of their images based on specific criteria, with 10% of images being re-assessed at the Oxford-based Ultrasound Quality Unit (compared using an adjusted kappa statistic); and (2) quantitative QC: assessment of measurement data by comparing the first, second and third measurements (intraobserver variability), remeasurement of caliper replacement in 10% (interobserver variability), both by Bland-Altman plots and plotting frequency histograms of the SD of triplicate measurements and assessing how many were above or below 2 SD of the expected distribution. The system allowed the sonographers' performances to be monitored regularly. RESULTS A high level of agreement between self- and external scoring was demonstrated for all measurements (κ = 0.99 (95% CI, 0.98-0.99) for HC, 0.98 (95% CI, 0.97-0.99) for AC and 0.96 (95% CI, 0.95-0.98) for FL). Intraobserver 95% limits of agreement (LoA) of ultrasound measures for HC, AC and FL were ± 3.3%, ± 5.6% and ± 6.2%, respectively; the corresponding values for interobserver LoA were ± 4.4%, ± 6.0% and ± 5.6%. The SD distribution of triplicate measurements for all biometric variables showed excessive variability for three of 31 sonographers, allowing prompt identification and retraining. CONCLUSIONS Qualitative and quantitative QC monitoring was feasible and highly reproducible in a large multicenter research study, which facilitated the production of high-quality ultrasound images. We recommend that the QC system we developed is implemented in future research studies and clinical practice. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.
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Multicenter Study |
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42 |
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Chim CS, Pang R, Liang R. Epigenetic dysregulation of the Wnt signalling pathway in chronic lymphocytic leukaemia. J Clin Pathol 2008; 61:1214-9. [DOI: 10.1136/jcp.2008.060152] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background:Wnt signalling has recently been implicated in the pathogenesis of cancer.Methods:This study investigated the activity of Wnt signalling in peripheral blood chronic lymphocytic leukaemia (CLL) lymphocytes, and the methylation status of seven soluble Wnt antagonist genes, including WIF1, DKK3, APC, SFRP1, SFRP2, SFRP4 and SFRP5, by using methylation-specific PCR in the peripheral blood CLL lymphocytes and bone marrow samples of patients with CLL at diagnosis.Results:In the peripheral blood CLL lymphocytes, constitutive activation of Wnt signalling was detected, associated with hypermethylation of the soluble Wnt inhibitor genes. In the diagnostic CLL marrow samples, methylation of the seven genes was detected in up to 36.4% of samples. Moreover, 23 (52.3%) patients had methylation of at least one of the seven genes, of whom 14 (60.8%) had methylation of two or more Wnt inhibitor genes. Apart from an association of advanced age with DKK3 methylation, there was no association of gene hypermethylation with either clinical characteristics (including age, gender, lymphocyte count at diagnosis, Rai stage and poor-risk karyotype) or survival.Conclusion:Wnt signalling is constitutively activated in CLL B lymphocytes in association with methylation of multiple soluble Wnt antagonist genes. Methylation of these soluble Wnt antagonist genes, occasionally multiple genes, in primary CLL marrow samples suggests an important role in CLL pathogenesis. Moreover, this study underscored the importance of studying methylation of a panel of, but not individual, genes regulating a cellular pathway.
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Xu FX, Zhou X, Shen F, Pang R, Liu SM. Decreased peripheral blood mitochondrial DNA content is related to HbA1c, fasting plasma glucose level and age of onset in type 2 diabetes mellitus. Diabet Med 2012; 29:e47-54. [PMID: 22211946 DOI: 10.1111/j.1464-5491.2011.03565.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS Mitochondrial DNA (mtDNA) content is essential for maintaining normal mitochondrial function, and the mitochondrial function is critical for the production and the release of insulin in Type 2 diabetes mellitus. We investigated whether peripheral blood mtDNA content was reduced in Type 2 diabetes, and what were the major factors? METHODS The mtDNA content of peripheral blood in a sample of 147 Type 2 diabetes and 170 normal Chinese subjects was determined by amplification of the mitochondrial gene CYT-B and normalized by a nuclear DNA β-globin gene. Fasting plasma glucose, HbA(1c) , fasting plasma insulin and lipid profile (HDL-cholesterol, LDL-cholesterol, total cholesterol, triglyceride) were analysed with commercial kits on an automatic analyser. RESULTS In Type 2 diabetes group, the mean HbA(1c) was 62 mmol/mol (7.8%). Moreover, BMI, systolic blood pressure, diastolic blood pressure, fasting plasma glucose, LDL-cholesterol, triglyceride, fasting plasma insulin and homeostasis model assessment for insulin resistance were significantly higher in Type 2 diabetes group than that in control group. Peripheral blood mtDNA content was 24% lower than that in the controls (1.4 ± 0.5 vs. 1.8 ± 0.7, P < 0.001). The mtDNA content was negatively correlated with BMI, fasting plasma glucose, fasting plasma insulin, homeostasis model assessment for insulin resistance (P < 0.01), and age, triglyceride and LDL-cholesterol levels (P < 0.05); while positively correlated with HDL-cholesterol level (P < 0.05) in both groups. Stepwise regression analysis indicated that HbA(1c), fasting plasma glucose and age of onset were the major factors affecting the mtDNA content in the Type 2 diabetes group; however, BMI was the only variable associated with lower mtDNA content in control group. CONCLUSION Our results demonstrate that lower peripheral blood mtDNA content is associated with Type 2 diabetes in Chinese individuals, and HbA(1c), fasting plasma glucose and age of onset are the major factors affecting the mtDNA content.
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Abstract
The amnestic effects of the intravenous hypnotic anesthetic agent 2,6-diisopropylphenol (propofol; Diprivan) were studied in a single-trial passive avoidance task. Mice were injected with propofol 10 min before or immediately after training. Memory was impaired in a dose-dependent fashion when the anesthetic was administered before learning, but no amnesia was apparent with posttraining injections. Examination of the acquisition of passive avoidance using a multitrial task showed that propofol-treated mice learned the response normally but forgot the learning significantly faster than vehicle-treated controls. The anterograde amnesia was not the result of state-dependent learning. Propofol also disrupted extinction of fear conditioning when the anesthetic was given during the extinction session. Propofol-induced amnesia could be attenuated by amphetamine (1 mg/kg) injected 30 min before the retention test.
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Eskenazi B, Bradman A, Finkton D, Purwar M, Noble JA, Pang R, Burnham O, Cheikh Ismail L, Farhi F, Barros FC, Lambert A, Papageorghiou AT, Carvalho M, Jaffer YA, Bertino E, Gravett MG, Altman DG, Ohuma EO, Kennedy SH, Bhutta ZA, Villar J. A rapid questionnaire assessment of environmental exposures to pregnant women in the INTERGROWTH-21st Project. BJOG 2013; 120 Suppl 2:129-38, v. [PMID: 24028080 DOI: 10.1111/1471-0528.12430] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2013] [Indexed: 11/28/2022]
Abstract
Impaired fetal growth and preterm birth are the leading causes of neonatal and infant mortality worldwide and there is a growing scientific literature suggesting that environmental exposures during pregnancy may play a causal role in these outcomes. Our purpose was to assess the environmental exposure of the Fetal Growth Longitudinal Study (FGLS) participants in the multinational INTERGROWTH-21(st) Project. First, we developed a tool that could be used internationally to screen pregnant women for such exposures and administered it in eight countries on a subsample (n = 987) of the FGLS participants. The FGLS is a study of fetal growth among healthy pregnant women living in relatively affluent areas, at low risk of adverse pregnancy outcomes and environmental exposures. We confirmed that most women were not exposed to major environmental hazards that could affect pregnancy outcomes according to the protocol's entry criteria. However, the instrument was able to identify some women that reported various environmental concerns in their homes such as peeling paint, high residential density (>1 person per room), presence of rodents or cockroaches (hence the use of pesticides), noise pollution and safety concerns. This screening tool was therefore useful for the purposes of the project and can be used to ascertain environmental exposures in studies in which the primary aim is not focused on environmental exposures. The instrument can be used to identify subpopulations for more in-depth assessment, (e.g. environmental and biological laboratory markers) to pinpoint areas requiring education, intervention or policy change.
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Research Support, U.S. Gov't, Non-P.H.S. |
12 |
23 |
11
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Napolitano R, Molloholli M, Donadono V, Ohuma EO, Wanyonyi SZ, Kemp B, Yaqub MK, Ash S, Barros FC, Carvalho M, Jaffer YA, Noble JA, Oberto M, Purwar M, Pang R, Cheikh Ismail L, Lambert A, Gravett MG, Salomon LJ, Bhutta ZA, Kennedy SH, Villar J, Papageorghiou AT. International standards for fetal brain structures based on serial ultrasound measurements from Fetal Growth Longitudinal Study of INTERGROWTH-21 st Project. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2020; 56:359-370. [PMID: 32048426 DOI: 10.1002/uog.21990] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 01/27/2020] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
OBJECTIVE To create prescriptive growth standards for five fetal brain structures, measured using ultrasound, in healthy, well-nourished women at low risk of impaired fetal growth and poor perinatal outcome, taking part in the Fetal Growth Longitudinal Study (FGLS) of the INTERGROWTH-21st Project. METHODS This was a complementary analysis of a large, population-based, multicenter, longitudinal study. The sample analyzed was selected randomly from the overall FGLS population, ensuring an equal distribution among the eight diverse participating sites and of three-dimensional (3D) ultrasound volumes across pregnancy (range: 15-36 weeks' gestation). We measured, in planes reconstructed from 3D ultrasound volumes of the fetal head at different timepoints in pregnancy, the size of the parieto-occipital fissure (POF), Sylvian fissure (SF), anterior horn of the lateral ventricle, atrium of the posterior horn of the lateral ventricle (PV) and cisterna magna (CM). Fractional polynomials were used to construct the standards. Growth and development of the infants were assessed at 1 and 2 years of age to confirm their adequacy for constructing international standards. RESULTS From the entire FGLS cohort of 4321 women, 451 (10.4%) were selected at random. After exclusions, 3D ultrasound volumes from 442 fetuses born without a congenital malformation were used to create the charts. The fetal brain structures of interest were identified in 90% of cases. All structures, except the PV, showed increasing size with gestational age, and the size of the POF, SF, PV and CM showed increasing variability. The 3rd , 5th , 50th , 95th and 97th smoothed centiles are presented. The 5th centiles for the POF and SF were 3.1 mm and 4.7 mm at 22 weeks' gestation and 4.6 mm and 9.9 mm at 32 weeks, respectively. The 95th centiles for the PV and CM were 8.5 mm and 7.5 mm at 22 weeks and 8.6 mm and 9.5 mm at 32 weeks, respectively. CONCLUSIONS We have produced prescriptive size standards for fetal brain structures based on prospectively enrolled pregnancies at low risk of abnormal outcome. We recommend these as international standards for the assessment of measurements obtained using ultrasound from fetal brain structures. © 2020 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
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Pang R, Teh LB, Rajan VS, Sng EH. Gonoccocal ophthalmia neonatorum caused by beta-lactamase-producing Neisseria gonorrhoeae. BRITISH MEDICAL JOURNAL 1979; 1:380. [PMID: 761020 PMCID: PMC1597936 DOI: 10.1136/bmj.1.6160.380] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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research-article |
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Abstract
Pavlovian fear conditioning was employed to investigate learning during general anesthesia. Mice were given three CS-UCS presentations while anesthetized with halothane. The CS was a 10-s tone and the UCS a 0.4-mA shock delivered intramuscularly to the hindlimbs via needle electrodes. Anesthetized control groups received either CS only, UCS only, or CS followed by a 3-min delayed UCS. Strength of fear conditioning was assessed by measuring duration of suppression of drinking induced by tone presentation in a test session conducted 24 h after training. Results showed that mice trained under anesthesia exhibited a significant amount of conditioned suppression relative to the anesthetized control groups. These results show that Pavlovian fear conditioning can occur under halothane anesthesia.
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Geng J, Liu G, Peng F, Yang L, Cao J, Li Q, Chen F, Kong J, Pang R, Zhang C. Decorin promotes myogenic differentiation and mdx mice therapeutic effects after transplantation of rat adipose-derived stem cells. Cytotherapy 2012; 14:877-86. [PMID: 22663383 DOI: 10.3109/14653249.2012.688944] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND AIMS Adipose-derived stem cells (ADSC) have been considered as attractive candidates for the treatment of Duchenne muscular dystrophy (DMD), but the rate of ADSC myogenesis is very low. Myostatin (Mstn), a negative regulator of myogenesis, is known to be responsible for limiting skeletal muscle regeneration. Decorin could bind Mstn and deactivate it. Decorin has been shown to improve myogenic differentiation in mdx mice. We hypothesized that inhibition of Mstn by using decorin may ameliorate myogenic differentiation of ADSC. METHODS Rat ADSC were transfected with the lentivirus-containing green fluorescence protein (GFP) and human decorin gene. The transfected ADSC were induced by 5-azacytidine (5-AzaC). The rates of myogenic differentiation and adipogenesis were detected. The transfected ADSC were injected into mdx mice and the expression of Mstn and decorin detected by Western blot. Dystrophin was detected after transfected ADSC transplantation by immunofluorescence staining and Western blot. Serum creatine kinase (CK) and histologic changes were also evaluated. RESULTS The optimal multiplicity of infection of ADSC was 10. Decorin improved muscle mass. In accordance with the increased muscle mass, dystrophin expression increased. Following the level of decorin increase, the Mstn expression decreased. Furthermore, serum CK and histologic changes in centrally nucleated fiber (CNF) decreased. CONCLUSIONS Improved myogenic differentiation of ADSC was observed by using decorin. This process was probably the result of decorin inhibiting Mstn. A new method of DMD therapy combining Mstn inhibition (using decorin) and ADSC transplantation is probably feasible.
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Research Support, Non-U.S. Gov't |
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Chen J, Li T, Pang R. miR-2703 regulates the chitin biosynthesis pathway by targeting chitin synthase 1a in Nilaparvata lugens. INSECT MOLECULAR BIOLOGY 2020; 29:38-47. [PMID: 31260146 DOI: 10.1111/imb.12606] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/25/2019] [Accepted: 06/26/2019] [Indexed: 06/09/2023]
Abstract
The chitin biosynthesis pathway is an important physiology process in arthropods. However, few microRNAs (miRNAs) involved in the regulation of the chitin biosynthesis pathway in insects have been reported until now. In this study, four groups of samples that either upregulated or downregulated the chitin biosynthesis pathway were collected for deep sequencing, and a total of 15 unique mature miRNAs with significantly different expression levels were found, including 11 known miRNAs and four novel miRNAs. Subsequently, we showed that miR-2703 and its new target gene chitin synthase 1a are important for ecdysone-induced chitin biosynthesis in Nilaparvata lugens, a serious insect pest of rice. The nymphs showed an obvious moulting defect phenotype, lower survival rate and significantly reduced chitin content after miR-2703 feeding or injection. Furthermore, we found that the transcription level of miR-2703 was not repressed by 20-hydroxyecdysone signalling after Broad-Complex (BR-C) double-stranded RNA (dsRNA) injection compared with the repressed levels after green fluorescent protein dsRNA injection, suggesting that the involvement of miR-2703 in the 20-hydroxyecdysone pathway contributes to BR-C activity. miR-2703 regulates the chitin biosynthesis pathway by targeting chitin synthase 1a in response to 20-hydroxyecdysone signalling.
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Pang R, Guo R, Wu X, Hu F, Liu M, Zhang L, Wang Z, Li K. Altered Regional Homogeneity in Chronic Insomnia Disorder with or without Cognitive Impairment. AJNR Am J Neuroradiol 2018; 39:742-747. [PMID: 29496724 DOI: 10.3174/ajnr.a5587] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/29/2017] [Indexed: 01/05/2023]
Abstract
BACKGROUND AND PURPOSE Many studies have shown that insomnia is an independent factor in cognitive impairment, but the involved neurobiological mechanisms remain unclear. We used regional homogeneity to explore the specific neurobiologic indicators of chronic insomnia disorder with mild cognitive impairment. MATERIALS AND METHODS Thirty-nine patients with insomnia were divided into a group with and without cognitive impairment; we also included a control group (n = 28). Abnormalities in brain functional activity were identified by comparing the regional homogeneity values for each brain region among the groups. RESULTS Subjective insomnia scores were negatively correlated with cognitive impairment after controlling for age, sex, and educational effects. Regions with significant differences in regional homogeneity values in the 3 groups were concentrated in the right medial prefrontal cortex, the right superior frontal gyrus, and the left superior occipital gyrus. Meanwhile, subjective insomnia scores were negatively correlated with the strength of the decreased regional homogeneity in the right medial prefrontal cortex. The increased regional homogeneity value in the right superior frontal gyrus was positively correlated with the Montreal Cognitive Assessment score in patients. CONCLUSIONS Our results indicate that decreased regional homogeneity values in the medial prefrontal cortex and increased regional homogeneity values in the cuneus may be important neurobiologic indicators of chronic insomnia disorder and accompanying cognitive impairment. Overall, our study described the regional homogeneity of the whole brain in chronic insomnia disorder with mild cognitive impairment and could be the basis for future studies.
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Research Support, Non-U.S. Gov't |
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Rajan VS, Sng EH, Pang R, Tan NJ, Thirumoorthy T, Yeo KL. HR 756--a new cephalosporin in the treatment of gonorrhoea caused by ordinary and penicillinase-producing strains of Neisseria gonorrhoeae. Br J Vener Dis 1980; 56:255-8. [PMID: 6253023 PMCID: PMC1045791 DOI: 10.1136/sti.56.4.255] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
HR 756, a new cephalosporin, was used in single intramuscular doses of 500 mg to treat 108 men and women with gonorrhoea caused by penicillinase-producing Neisseria gonorrhoeae (PPNG) and non-PPNG. Of 102 patients followed up, 99 (97.05%) were cured. Cure rates for PPNG infections and non-PPNG infections were 98.18% and 95.74% respectively. Few adverse side effects were recorded but possible cross-sensitisation with penicillin was observed. Clinical and laboratory antibiotic susceptibility results correlated well. It is concluded that this drug is safe and effective in treating both PPNG and non-PPNG infectons.
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Pan XH, Song QQ, Dai JJ, Yao X, Wang JX, Pang RQ, He J, Li ZA, Sun XM, Ruan GP. Transplantation of bone marrow mesenchymal stem cells for the treatment of type 2 diabetes in a macaque model. Cells Tissues Organs 2014; 198:414-27. [PMID: 24686078 DOI: 10.1159/000358383] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2014] [Indexed: 12/22/2022] Open
Abstract
Bone marrow mesenchymal stem cells (BMSCs) are self-renewing, multipotent cells that can migrate to pathological sites and thereby provide a new treatment in diabetic animals. Superparamagnetic iron oxide/4',6-diamidino-2-phenylindole (DAPI) double-labeled BMSCs were transplanted into the pancreatic artery of macaques to treat type 2 diabetes mellitus (T2DM). The treatment efficiency of BMSCs was also evaluated. After successful induction of the T2DM model, the treatment group received double-labeled BMSCs via the pancreatic artery. Six weeks after BMSC transplantation, the fasting blood glucose and blood lipid levels measured in the treatment group were significantly lower (p < 0.05) than in the model group, although they were not reduced to normal levels (p < 0.05). Additionally, the serum C-peptide levels were significantly increased (p < 0.05). An intravenous glucose tolerance test and C-peptide release test had significant changes to the area under the curve. Within 14 days of the transplantation of labeled cells, the pancreatic and kidney tissue of the treatment group emitted a negative signal that was visible on magnetic resonance imaging (MRI). Six weeks after transplantation, DAPI signals appeared in the pancreatic and kidney tissue, which indicates that the BMSCs were mainly distributed in damaged tissue. Labeled stem cells can be used to track migration and distribution in vivo by MRI. In conclusion, the transplantation of BMSCs for the treatment of T2DM is safe and effective.
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Qiao L, Li GHY, Dai Y, Wang J, Li Z, Zou B, Gu Q, Ma J, Pang R, Lan HY, Wong BCY. Gene expression profile in colon cancer cells with respect to XIAP expression status. Int J Colorectal Dis 2009; 24:245-60. [PMID: 18704457 DOI: 10.1007/s00384-008-0566-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/29/2008] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND AIMS We observed a marked synergism between peroxisome proliferator-activated receptor gamma (PPARgamma) ligands and X-linked inhibitor of apoptosis (XIAP) down-regulation in colon cancer. In the current study, we detected the gene expression profile in HCT116 cells treated with or without PPARgamma ligand troglitazone. MATERIALS AND METHODS HCT116-XIAP(+/+) and HCT116-XIAP(-/-) cells were treated with or without 50 microM troglitazone for 48 h. Gene expressions were detected by microarray, and selected genes were validated by reverse-transcriptase polymerase chain reaction (PCR), real-time PCR, and Western blot. RESULTS Relative to HCT116-XIAP(+/+) cells, 58 genes were up-regulated and 33 genes down-regulated in HCT116-XIAP(-/-) cells, all by > or =4-fold. These genes could be classified into a wide variety of functional classes, but we focused on those related to angiogenesis, apoptosis, and proliferation. Thus, two pro-apoptotic genes and one pro-proliferation gene were up-regulated in HCT116-XIAP(-/-) cells. Two pro-proliferation genes, one pro-angiogenesis gene, one anti-angiogenesis gene, and one anti-apoptosis gene were down-regulated in HCT116-XIAP(-/-) cells. Relative to HCT116-XIAP(+/+) cells treated with troglitazone, 137 genes were up-regulated, and 31 genes were down-regulated in troglitazone-treated HCT116-XIAP(-/-) cells, all by > or =4-fold. Among the up-regulated genes were two anti-angiogenesis genes, seven pro-apoptosis genes, and six anti-proliferation genes. Among the down-regulated genes were one anti-angiogenesis gene, one pro-angiogenesis gene, one anti-apoptosis gene, one anti-proliferation gene, and two pro-proliferation genes. CONCLUSION Down-regulation of XIAP in HCT116 cells with or without troglitazone treatment was associated with changes of gene expression that favor increased tendency of apoptosis, decreased cell proliferation, and angiogenesis potential.
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Pang R, Li Y, Dong Y, Liang Z, Zhang Y, Zhang W. Identification of promoter polymorphisms in the cytochrome P450 CYP6AY1 linked with insecticide resistance in the brown planthopper, Nilaparvata lugens. INSECT MOLECULAR BIOLOGY 2014; 23:768-778. [PMID: 25124988 DOI: 10.1111/imb.12121] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Imidacloprid resistance in the brown planthopper, Nilaparvata lugens, is primarily the result of the over-expression of cytochrome P450 monooxygenases. Here, a field-collected strain of N. lugens was shown to be highly resistant to both imidacloprid and buprofezin. Insecticide exposure and quantitative real-time PCR revealed that its resistance was mainly associated with a cytochrome P450 gene, CYP6AY1. CYP6AY1 is known to metabolize imidacloprid but its effect on buprofezin is unclear. In the 5'-untranslated region of CYP6AY1, a novel alternative splicing was detected. After a 1990-bp promoter region was cloned, its basal luciferase activity was assessed. Furthermore, genotyping studies identified 12 variations in the promoter region that discriminated between the field-collected and control strain. Finally, survival bioassays revealed a single nucleotide polymorphism and an insertion-deletion polymorphism linked to buprofezin and imidacloprid resistance. Mutagenesis of these sites enhanced the promoter activity of CYP6AY1. These results suggest that promoter polymorphisms may affect P450-mediated multiple insecticide resistance of pests.
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Rodriguez-Sibaja MJ, Villar J, Ohuma EO, Napolitano R, Heyl S, Carvalho M, Jaffer YA, Noble JA, Oberto M, Purwar M, Pang R, Cheikh Ismail L, Lambert A, Gravett MG, Salomon LJ, Drukker L, Barros FC, Kennedy SH, Bhutta ZA, Papageorghiou AT. Fetal cerebellar growth and Sylvian fissure maturation: international standards from Fetal Growth Longitudinal Study of INTERGROWTH-21 st Project. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2021; 57:614-623. [PMID: 32196791 DOI: 10.1002/uog.22017] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/26/2020] [Accepted: 03/07/2020] [Indexed: 06/10/2023]
Abstract
OBJECTIVE To construct international ultrasound-based standards for fetal cerebellar growth and Sylvian fissure maturation. METHODS Healthy, well nourished pregnant women, enrolled at < 14 weeks' gestation in the Fetal Growth Longitudinal Study (FGLS) of INTERGROWTH-21st , an international multicenter, population-based project, underwent serial three-dimensional (3D) fetal ultrasound scans every 5 ± 1 weeks until delivery in study sites located in Brazil, India, Italy, Kenya and the UK. In the present analysis, only those fetuses that underwent developmental assessment at 2 years of age were included. We measured the transcerebellar diameter and assessed Sylvian fissure maturation using two-dimensional ultrasound images extracted from available 3D fetal head volumes. The appropriateness of pooling data from the five sites was assessed using variance component analysis and standardized site differences. For each Sylvian fissure maturation score (left or right side), mean gestational age and 95% CI were calculated. Transcerebellar diameter was modeled using fractional polynomial regression, and goodness of fit was assessed. RESULTS Of those children in the original FGLS cohort who had developmental assessment at 2 years of age, 1130 also had an available 3D ultrasound fetal head volume. The sociodemographic characteristics and pregnancy/perinatal outcomes of the study sample confirmed the health and low-risk status of the population studied. In addition, the fetuses had low morbidity and adequate growth and development at 2 years of age. In total, 3016 and 2359 individual volumes were available for transcerebellar-diameter and Sylvian-fissure analysis, respectively. Variance component analysis and standardized site differences showed that the five study populations were sufficiently similar on the basis of predefined criteria for the data to be pooled to produce international standards. A second-degree fractional polynomial provided the best fit for modeling transcerebellar diameter; we then estimated gestational-age-specific 3rd , 50th and 97th smoothed centiles. Goodness-of-fit analysis comparing empirical centiles with smoothed centile curves showed good agreement. The Sylvian fissure increased in maturation with advancing gestation, with complete overlap of the mean gestational age and 95% CIs between the sexes for each development score. No differences in Sylvian fissure maturation between the right and left hemispheres were observed. CONCLUSION We present, for the first time, international standards for fetal cerebellar growth and Sylvian fissure maturation throughout pregnancy based on a healthy fetal population that exhibited adequate growth and development at 2 years of age. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
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Multicenter Study |
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Sng EH, Rajan VS, Pang R, Yeo KL. Susceptibility of Neisseria gonorrhoeae to cefotaxime and ceftizoxime. Br J Vener Dis 1981; 57:162-4. [PMID: 6263403 PMCID: PMC1045906 DOI: 10.1136/sti.57.3.162] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Two hundred and thirty-nine penicillinase-positive and 240 penicillinase-negative strains of Neisseria gonorrhoeae were tested for their susceptibility to cefotaxime. All were susceptible to cefotaxime at a concentration of 0.062 micrograms/ml. Penicillinase-negative strains were less susceptible than penicillinase-positive strains. This is attributed to the use of prophylactic antibiotics by prostitutes, which has led to the selection of less susceptible penicillinase-negative strains but has not affected the susceptibility of penicillinase-positive strains. The minimum inhibitory concentrations of cefotaxime showed significant positive correlations with those of penicillin, ampicillin, tetracycline, and kanamycin but had a negative correlation with spectinomycin. The related cephalosporin, ceftizoxime, was found to be as effective as cefotaxime against penicillinase-positive and penicillinase-negative gonococci.
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Pan XH, Chen YH, Yang YK, Zhang XJ, Lin QK, Li ZA, Cai XM, Pang RQ, Zhu XQ, Ruan GP. Relationship between senescence in macaques and bone marrow mesenchymal stem cells and the molecular mechanism. Aging (Albany NY) 2019; 11:590-614. [PMID: 30673631 PMCID: PMC6366955 DOI: 10.18632/aging.101762] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 01/05/2019] [Indexed: 04/18/2023]
Abstract
The relationship between bone marrow mesenchymal stem cells (BMSCs) and aging, as well as the antiaging effects of BMSCs, was observed. An aging macaque BMSC model was established. We isolated BMSCs from young and aged macaques and used RT-PCR and Western blot to confirm the aging-related mRNAs and their expression, revealing that TERT, SIRT1 and SIRT6 expression was decreased in the aged BMSCs. The morphology, immunophenotype, differentiation potential, proliferation potential, and antiaging effects of aged and young BMSCs on 293T cells were compared. The expression of aging-related genes and the difference between the secreted cytokines in natural aging and induced aging BMSCs were observed. The transcriptome of peripheral blood mononuclear cells from macaques was analyzed by high-throughput sequencing. Finally, the transcriptional characteristics and regulatory mechanisms of gene transcription in aging macaques were investigated.
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Jiang LH, Zhang YL, Gong XM, Pang R, Zhang S, Li CY, Su Q. LiSr4(BO3)3:Ce3+ phosphor as a new material for ESR dosimetry. Appl Radiat Isot 2013; 84:66-9. [PMID: 24321766 DOI: 10.1016/j.apradiso.2013.11.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 09/09/2013] [Accepted: 10/31/2013] [Indexed: 11/28/2022]
Abstract
LiSr4(BO3)3:0.01Ce(3+) phosphor was investigated to assess its potential as a material for measurements of radiotherapeutic doses with electron spin resonance (ESR). The ESR spectrum of the phosphor irradiated with (60)Co features five ESR signals. An isochronal annealing experiment has shown that the strongest of these signals is associated with the same trap center as the 473 K peak on the TL glow curve of this material. The dose-response is linear in the studied range from 0.89 to 90.30 Gy. Fading of the signal was also investigated.
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Rosman E, Quartermain D, Pang R, Turndorf H. Halothane anesthesia causes state-dependent retrieval failure in mice. Physiol Behav 1992; 52:449-53. [PMID: 1409904 DOI: 10.1016/0031-9384(92)90330-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Effects of exposure to halothane on memory processing was studied using single-trial inhibitory avoidance learning to measure retention. Mice were anesthetized with halothane either before training, immediately after training, or both before training and before testing. Results showed that memory was not impaired by posttraining halothane exposure, indicating that the anesthetic does not cause retrograde amnesia. Mice trained after recovery from halothane showed a robust memory loss 24 h later. This deficit could be alleviated by reexposure to the anesthetic before the retention test. Mice given multiple training trials following recovery from the anesthetic showed a normal rate of learning when compared with controls, but deficient retention. This indicates that the performance deficit was the result of impaired retention (anterograde amnesia) rather than disrupted acquisition. Anterograde amnesia occurred when training was delayed up to 2 h after recovery from anesthesia. These findings indicate that the memory impairment following halothane anesthesia is the result of a state-dependent retrieval failure.
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