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1.
Opt Express ; 31(4): 5767-5776, 2023 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-36823849

RESUMO

The temporal modulation of an electron bunch train accelerated from a foil target irradiated by an intense laser pulse is studied by measuring the coherent transition radiation (CTR) from the rear surface of a target. We experimentally obtained CTR spectra from a 1 µm thick foil target irradiated at a maximum intensity of 6.5 × 1019 W/cm2. Spectral redshifts of the emitted radiation corresponding to increases in laser intensity were observed. These measurements were compared with the theoretical calculation of CTR spectra considering ultrafast surface dynamics, such as plasma surface oscillation and relativistically induced transparency. Plasma surface oscillations induce a spectral redshift, while relativistic transparency causes a spectral blueshift. Both effects are required to find reasonable agreement with the experiment over the entire range of laser intensities.

2.
Am J Transplant ; 18(2): 492-503, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28992380

RESUMO

Organ shortage continues to challenge the field of transplantation. One potential group of donors are those who have been transplant recipients themselves, or Organ Donation After Transplant (ODAT) donors. We conducted a retrospective cohort study to describe ODAT donors and to compare outcomes of ODAT grafts versus conventional grafts. From October 1, 1987 to June 30, 2015, 517 former recipients successfully donated 803 organs for transplant. Former kidney recipients generally survived a median of approximately 4 years before becoming an ODAT donor whereas liver, lung, and heart recipients generally survived less than a month prior to donation. In the period June 1, 2005 to December 31, 2014, liver grafts from ODAT donors had a significantly higher risk of graft failure compared to non-ODAT liver transplants (P = .008). Kidney grafts donated by ODAT donors whose initial transplant occurred >1 year prior were associated with significantly increased graft failure (P = .012). Despite increased risk of graft failure amongst certain ODAT grafts, 5-year survival was still high. ODAT donors should be considered another form of expanded criteria donor under these circumstances.


Assuntos
Sobrevivência de Enxerto , Doadores Vivos , Transplante de Órgãos/mortalidade , Complicações Pós-Operatórias , Obtenção de Tecidos e Órgãos/estatística & dados numéricos , Transplantados/estatística & dados numéricos , Adolescente , Adulto , Feminino , Seguimentos , Rejeição de Enxerto , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Prognóstico , Sistema de Registros , Reoperação , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida , Obtenção de Tecidos e Órgãos/métodos , Adulto Jovem
3.
Osteoporos Int ; 25(10): 2383-8, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24927689

RESUMO

SUMMARY: We compared circulating levels of Wnt inhibitors among patients with high bone mass mutations in LRP5, unaffected kindred, and unrelated normal controls. Inhibitors were unchanged in affected and unaffected kindred. We saw no meaningful differences between controls and affected individuals. LRP5 signaling may not influence circulating levels of these inhibitors. INTRODUCTION: It is thought that gain-of-function mutations in LRP5 result in high bone mass syndromes because these allelic variants confer resistance to the actions of endogenous inhibitors of Wnt signaling. We therefore attempted to determine if circulating levels of Wnt inhibitors are altered in patients with gain-of-function mutations in LRP5. METHODS: This is a cross-sectional study in a university research center. Serum was collected from consented volunteers known to have either the G171V or N198S gain-of-function mutations in LRP5, kindred members affected with either mutation, unrelated kindred, and unrelated normal age-matched controls. BMD was provided or measured on site. RESULTS: There were no significant differences found in the serum levels of sclerostin (SOST), Dickkopf-1 (Dkk-1), or secreted frizzled-related protein-4 (SFRP-4) in affected vs. unaffected individuals from different kindreds or when compared to age-matched unrelated normal individuals. Mean serum SOST values in affected and unaffected kindred members and unrelated normal controls were 52.7 ± 6.1, 36.5 ± 9.6, and 54.8 ± 5.4, respectively. For Dkk-1, the values were 25.9 ± 3.4, 25.7 ± 3.0, and 17.3 ± 2.3 and for SFRP-4, 38.1 ± 2.3, 39.8 ± 3.6, and 28.5 ± 1.7. Serum levels of RANKL and osteoprotegerin (OPG) were not different in the three groups. CONCLUSIONS: Circulating levels of endogenous Wnt inhibitors do not change in patients with gain-of-function mutations in LRP5 including Dkk1, which is suppressed by Wnt signaling. It may be that circulating levels of Wnt inhibitors do not reflect changes in target tissues. It is also possible that other mechanisms besides or in addition to resistance in Wnt inhibitors explains the skeletal effects of these mutations.


Assuntos
Densidade Óssea/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Mutação , Proteínas Adaptadoras de Transdução de Sinal , Adulto , Idoso , Proteínas Morfogenéticas Ósseas/sangue , Estudos de Casos e Controles , Feminino , Marcadores Genéticos , Genótipo , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/sangue , Masculino , Pessoa de Meia-Idade , Osteoprotegerina/sangue , Proteínas Proto-Oncogênicas/sangue , Ligante RANK/sangue , Caracteres Sexuais , Via de Sinalização Wnt/genética , Via de Sinalização Wnt/fisiologia
4.
Phys Rev Lett ; 112(24): 242501, 2014 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-24996084

RESUMO

Cross sections of 1n-removal reactions from the neutron-rich nucleus (37)Mg on C and Pb targets and the parallel momentum distributions of the (37)Mg residues from the C target have been measured at 240 MeV/nucleon. A combined analysis of these distinct nuclear- and Coulomb-dominated reaction data shows that the (37)Mg ground state has a small 1n separation energy of 0.22(-0.09)(+0.12) MeV and an appreciable p-wave neutron single-particle strength. These results confirm that (37)Mg lies near the edge of the "island of inversion" and has a sizable p-wave neutron halo component, the heaviest such system identified to date.

5.
Clin Nephrol ; 74(5): 372-83, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20979946

RESUMO

This review of 2,586 renal biopsies over the past 3 decades in Singapore documents the changing pattern of glomerulonephritis (GN) from that of a third world country to that of a developed nation. In the 1st decade, mesangial proliferative glomerulonephritis was the most common form of primary GN, just as it was in the surrounding Asian countries. In the 2nd decade, the prevalence of mesangial proliferative GN decreased with a rise in membranous, GN which is also seen in China and Thailand. In the 3rd decade, there was a dramatic increase in focal sclerosing glomerulosclerosis. This increase reflects aging and obesity in keeping with more developed countries like Australia, India, Thailand and the United States of America. IgA nephritis remains the most common GN. Apart from the geographical influence, other socioeconomic factors play a significant role in the evolution of the renal biopsy pattern. Mesangial proliferative GN remains prevalent in many Asian countries, but in Singapore the prevalence is decreasing just as it is in Japan, Korea and Malaysia. Worldwide, the prevalence of focal sclerosing glomerulosclerosis continues to increase in many countries.


Assuntos
Glomerulonefrite/epidemiologia , Rim/patologia , Adolescente , Adulto , Idoso , Biópsia , Distribuição de Qui-Quadrado , Países Desenvolvidos/estatística & dados numéricos , Países em Desenvolvimento/estatística & dados numéricos , Feminino , Mesângio Glomerular/patologia , Glomerulonefrite/patologia , Glomerulonefrite por IGA/epidemiologia , Glomerulonefrite por IGA/patologia , Glomerulonefrite Membranoproliferativa/epidemiologia , Glomerulonefrite Membranoproliferativa/patologia , Glomerulonefrite Membranosa/epidemiologia , Glomerulonefrite Membranosa/patologia , Glomerulosclerose Segmentar e Focal/epidemiologia , Glomerulosclerose Segmentar e Focal/patologia , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Prevalência , Medição de Risco , Fatores de Risco , Singapura/epidemiologia , Fatores de Tempo , Adulto Jovem
6.
Clin Nephrol ; 71(6): 617-24, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19473629

RESUMO

AIM: Several short-term studies have reported the efficacy of high-dose ARB in reducing proteinuria in patients with diabetic nephropathy. The benefits of long-term high-dose ARB losartan in IgA nephritis have not been explored. METHOD: This was a 6-year randomized trial in 207 patients with IgA nephritis comparing high-dose ARB (losartan 200 mg/day) with normal dose ARB (losartan 100 mg/day), normal dose ACEI (20 mg/day) and low-dose ACEI (10 mg/day). Multivariate ANOVA was used to test the effect of drug treatment on both eGFR and total urinary protein (TUP). RESULTS: Comparing patients on high-dose ARB (n = 63) with those on normal dose ARB (n = 43), normal dose ACEI (n = 61) and low-dose ACEI (n = 40), patients on high Dose ARB had significantly higher eGFR (p < 0.0005) and lower proteinuria (p < 0.005) at the end of the study. The loss in eGFR was 0.7 ml/min/year for high-dose ARB compared to 3.2 - 3.5 ml/ min/year for the other 3 groups (p = 0.0005). There were more patients on high-dose ARB with improvement in eGFR compared to other 3 groups (p < 0.001). CONCLUSION: Data from this study suggest that high-dose ARB therapy is more efficacious in reducing proteinuria and preserving renal function when compared with normal dose ARB and ACEI. In Year 5, patients on high-dose ARB had a gain in eGFR suggesting that there is possibility of recovery of renal function in these patients on long-term high-dose therapy.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/administração & dosagem , Inibidores da Enzima Conversora de Angiotensina/administração & dosagem , Enalapril/administração & dosagem , Glomerulonefrite por IGA/tratamento farmacológico , Losartan/administração & dosagem , Adulto , Relação Dose-Resposta a Droga , Feminino , Taxa de Filtração Glomerular/efeitos dos fármacos , Humanos , Masculino , Resultado do Tratamento
7.
Reprod Domest Anim ; 44(5): 797-804, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19032437

RESUMO

To stably maintain pregnancy, several genes are expressed in the uterus. In particular, the endometrial expression of genes encoding growth factors appears to play a key role in maternal-foetal communication. The previous studies characterized the endometrial expression kinetics of the genes encoding epidermal growth factor (EGF), its receptor (EGFR), transforming growth factor-alpha (TGF-alpha), amphiregulin (Areg), heparin-binding (Hb) EGF and calbindin-D9k (CaBP-9k) in pigs during implantation. Here, we further characterized the expression patterns of these molecules during the entire porcine pregnancy. Porcine uteri were collected at pregnancy days (PD) 12, 15, 30, 60, 90 and 110 and subjected to RT-PCR. EGF and EGFR showed similar expression patterns, being highly expressed around implantation and then disappearing. TGF-alpha and Areg expression levels rose steadily until they peaked at PD30, after which they gradually decreased to PD12 levels. This Areg mRNA expression pattern was confirmed by real-time PCR and similar Areg protein expression patterns were observed. Immunohistochemical analysis of PD60 uteri revealed Areg in the glandular and luminal epithelial cells. Hb EGF was steadily expressed throughout the entire pregnancy, while CaBP-9k was expressed strongly on PD12, and then declined sharply on PD15 before recovering slightly for the remainder of the pregnancy. Thus, the EGF family may play a key role during implantation in pigs. In addition, CaBP-9k may help to maintain uterine quiescence during pregnancy by sequestering cytoplasmic Ca(2+).


Assuntos
Endométrio/química , Fator de Crescimento Epidérmico/genética , Expressão Gênica , Suínos , Anfirregulina , Animais , Calbindinas , Implantação do Embrião/fisiologia , Receptores ErbB/genética , Feminino , Idade Gestacional , Glicoproteínas/análise , Glicoproteínas/genética , Fator de Crescimento Semelhante a EGF de Ligação à Heparina , Peptídeos e Proteínas de Sinalização Intercelular/análise , Peptídeos e Proteínas de Sinalização Intercelular/genética , Reação em Cadeia da Polimerase/veterinária , Gravidez , RNA Mensageiro/análise , Proteína G de Ligação ao Cálcio S100/genética , Fator de Crescimento Transformador alfa/genética
8.
Artigo em Inglês | MEDLINE | ID: mdl-30507529

RESUMO

This work presents fabrication of thermal-piezoresistive nanoelectromechanical silicon disk resonators and their characterization as highly sensitive mass sensors. Forest of multiwall carbon nanotubes (MWCNTs) has been grown on the top surface of the fabricated devices, increasing the resonator effective surface area, which, in turn, increases the adsorption capacity and, therefore, the frequency shift of the sensor in molecular or particulate detection applications. To investigate the effect of the enhanced surface area on frequency shift, devices with and without MWCNTs were exposed to an aqueous solution of manganese sulfate for different deposition times and the resonance frequency shift was recorded accordingly. The measured frequency shift for the devices covered with MWCNTs was 14× higher than similar bare silicon devices. Furthermore, mass loading experiments were performed using gold nanoparticles as the loading mass. A novel way to attach gold nanoparticles on the carbon nanotubes (CNTs) wall was developed here. Oxygen plasma treatment introduced dangling bonds on the MWCNTs walls to facilitate the bonding between them and trimethoxysilane aldehyde molecules, forming the self-assembled monolayer (SAM). After functionalization of the device with SAM and antiinfluenza H1N1 viruses (AB), the device was exposed to a solution of Antimouse IgG (whole molecule)-gold antibody produced in goat products. The results showed more than three times response enhancement for the resonators with MWCNTs.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Nanotecnologia/instrumentação , Nanotubos de Carbono/química , Animais , Anticorpos Antivirais , Técnicas Biossensoriais/instrumentação , Desenho de Equipamento , Vírus da Influenza A Subtipo H1N1 , Compostos de Manganês/química , Camundongos , Óxidos/química , Propriedades de Superfície
9.
Meat Sci ; 144: 186-192, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29735356

RESUMO

The Australian pork industry is strongly committed to assuring the integrity of its product, with substantial research investment made over the past ten years to develop and implement systems to assure the consistency and quality of fresh pork and to enable accurate tracing of unpackaged fresh pork back to property of origin using trace elemental profiling. These initiatives are pivotal to allow Australian pork of guaranteed eating quality to be successfully positioned as higher value products, across a range of international and domestic markets, whilst managing any threats of product substitution. This paper describes the current status of the development of a predictive eating quality model for Australian pork, utilizing eating quality datasets generated from recent Australian studies. The implementation of trace elemental profiling, by Physi-Trace™, to verify and defend provenance claims and support the supply of consistently high eating quality Australian pork to its customers, is also discussed.


Assuntos
Carne Vermelha/normas , Animais , Austrália , Comportamento do Consumidor , Análise de Alimentos , Humanos , Suínos
10.
Nat Commun ; 9(1): 3287, 2018 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-30120234

RESUMO

Leukocytes are coated with a layer of heterogeneous carbohydrates (glycans) that modulate immune function, in part by governing specific interactions with glycan-binding proteins (lectins). Although nearly all membrane proteins bear glycans, the identity and function of most of these sugars on leukocytes remain unexplored. Here, we characterize the N-glycan repertoire (N-glycome) of human tonsillar B cells. We observe that naive and memory B cells express an N-glycan repertoire conferring strong binding to the immunoregulatory lectin galectin-9 (Gal-9). Germinal center B cells, by contrast, show sharply diminished binding to Gal-9 due to upregulation of I-branched N-glycans, catalyzed by the ß1,6-N-acetylglucosaminyltransferase GCNT2. Functionally, we find that Gal-9 is autologously produced by naive B cells, binds CD45, suppresses calcium signaling via a Lyn-CD22-SHP-1 dependent mechanism, and blunts B cell activation. Thus, our findings suggest Gal-9 intrinsically regulates B cell activation and may differentially modulate BCR signaling at steady state and within germinal centers.


Assuntos
Linfócitos B/metabolismo , Galectinas/metabolismo , Polissacarídeos/química , Polissacarídeos/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Transdução de Sinais , Amino Açúcares/química , Sinalização do Cálcio , Linhagem Celular , Núcleo Celular/metabolismo , Proliferação de Células , Endocitose , Galectinas/sangue , Centro Germinativo/metabolismo , Humanos , Fatores Imunológicos/metabolismo , Memória Imunológica , Antígenos Comuns de Leucócito/metabolismo , Ativação Linfocitária/imunologia , Tecido Linfoide/metabolismo , Modelos Biológicos , N-Acetilexosaminiltransferases/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Fosforilação , Ligação Proteica , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismo , Quinases da Família src/metabolismo
11.
Mol Cell Biol ; 21(13): 4302-10, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11390658

RESUMO

The discovery that the V(D)J recombinase functions as a transposase in vitro suggests that transposition by this system might be a potent source of genomic instability. To gain insight into the mechanisms that regulate transposition, we investigated a phenomenon termed target commitment that reflects a functional association between the RAG transposase and the target DNA. We found that the V(D)J recombinase is quite promiscuous, forming productive complexes with target DNA both before and after donor cleavage, and our data indicate that the rate-limiting step for transposition occurs after target capture. Formation of stable target capture complexes depends upon the presence of active-site metal binding residues (the DDE motif), suggesting that active-site amino acids in RAG-1 are critical for target capture. The ability of the RAG transposase to commit to target prior to cleavage may result in a preference for transposition into nearby targets, such as immunoglobulin and T-cell receptor loci. This could bias transposition toward relatively "safe" regions of the genome. A preference for localized transposition may also have influenced the evolution of the antigen receptor loci.


Assuntos
DNA Nucleotidiltransferases/metabolismo , Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Genes RAG-1 , Recombinação Genética , Animais , Células CHO , Cálcio/metabolismo , Cricetinae , DNA Nucleotidiltransferases/genética , Proteínas de Ligação a DNA/genética , Cinética , Magnésio/metabolismo , Ligação Proteica , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , VDJ Recombinases
12.
J Nanosci Nanotechnol ; 6(11): 3608-13, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17252821

RESUMO

An electrochemical sensor is built using vertically grown multi-walled carbon nanotubes (MWNTs) micro-array to detect methanol concentration in water. This study is done for the potential use of the array as methanol sensor for portable units of direct methanol fuel cells (DMFCs). Platinum (Pt) nanoparticles electro-deposited CNTs (Pt/CNTs) electrode shows high sensitivity in the measurement of methanol concentration in water with cyclic voltammetry (CV) measurement at room temperature. Further investigation has also been undertaken to measure the concentration by changing the amount of the mixture of methanol and formic acid in water. We compared the performance of our micro array sensor built with Pt/CNTs electrodes versus that of Pt wire electrode using CV measurement. We found that our Pt/CNTs array sensor shows high sensitivity and detects methanol concentrations in the range of 0.04 M to 0.10 M. In addition, we found that co-use of formic acid as electrolyte enables us to measure up to 1.0 M methanol concentration.


Assuntos
Eletroquímica/métodos , Nanotecnologia/métodos , Nanotubos de Carbono/química , Relação Dose-Resposta a Droga , Fontes de Energia Elétrica , Eletrodos , Formiatos/química , Nanopartículas Metálicas/química , Metanol/química , Microeletrodos , Microscopia Eletrônica de Varredura , Nanopartículas/química , Platina/química , Propriedades de Superfície
13.
Nurse Educ Today ; 26(2): 139-50, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16213063

RESUMO

AIM: Nurses' spiritual care perceptions and practices are explored by identifying profiles of nurses studying in a part-time baccalaureate course in a local Hong Kong university. Relationships between nurses' spiritual care perceptions and their practices are explored. RESEARCH METHOD: Hundred and ninety three nurses completed a structured questionnaire. OUTCOME MEASURES: Spiritual care perceptions and practices. RESULTS: Two-step cluster analysis yielded three clusters. Clusters A, B, and C consisted of 15.0% (n = 29), 44.6% (n = 86), and 40.4% (n = 78), respectively. Cluster A nurses were characterized by relatively negative spiritual care perceptions and practices. Cluster C nurses reported positive perceptions, but negative practices; they mainly chose 'uncertain' for most items on both scales. Cluster B was a large group of nurses holding both positive spiritual care perceptions and practices. Significant differences towards spiritual care were found among clusters. Nurses' perceptions were significant positively correlated with practices (r = 0.62). High positive correlations were found between the two scales (r = 0.83) for nurses in Cluster A, for nurses in Clusters B and C, low positive correlations (r = 0.37) were found. CONCLUSION: Three clusters of Hong Kong nurses were differentiated. They showed differences in the level of their spiritual care perceptions and practices. Despite their level of spiritual care perceptions, nurses seldom incorporated spiritual care practices into their daily nursing care, and the level of spiritual care awareness of some nurses was low. Findings may be used to improve support of nurses, to ensure sensitive spiritual care in their daily practices, and to enhance nursing curricula.


Assuntos
Atitude do Pessoal de Saúde , Conhecimentos, Atitudes e Prática em Saúde , Papel do Profissional de Enfermagem/psicologia , Recursos Humanos de Enfermagem/psicologia , Espiritualidade , Estudantes de Enfermagem/psicologia , Adulto , Análise de Variância , Competência Clínica/normas , Análise por Conglomerados , Currículo , Bacharelado em Enfermagem , Reeducação Profissional , Análise Fatorial , Feminino , Necessidades e Demandas de Serviços de Saúde , Saúde Holística , Hong Kong , Humanos , Masculino , Pesquisa em Avaliação de Enfermagem , Pesquisa Metodológica em Enfermagem , Recursos Humanos de Enfermagem/educação , Autoeficácia , Inquéritos e Questionários
14.
J Mol Biol ; 223(3): 617-26, 1992 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-1542109

RESUMO

The base alterations induced by four alkylating agents, methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS), N-nitroso-N-methylurea (MNU), and N-nitroso-N-ethylurea (ENU), have been determined at the URA3 locus in the yeast Saccharomyces cerevisiae. The mutagen treatment was carried out on yeast cells in the logarithmic phase of growth. The mutants were selected by their resistance to 7.3 mM-5-fluoroorotic acid at pH 3.8. DNA sequence analysis was carried out by the dideoxy chain termination method. The alkylating agents were selected for their widely differing Swain-Scott substrate constants (s values), which are as follows: MMS, s = 0.83; EMS, s = 0.67; MNU, s = 0.42; ENU, s = 0.26. A higher s value is correlated with a higher ratio of 7-alkylguanine to O6-alkylguanine in native DNA in vitro. 125 forward mutations from URA3----ura3 were sequenced with marked differences in the mutational spectra being observed as the s value changed. Five hotspots were recorded for the four alkylating agents. They were all G.C----A.T transition mutations. There was one common hotspot for all of them; there were two additional ones for the two ethylating agents (ENU and EMS) and two different ones for MNU. Four of the five hotspots have the 5'-GG-3' sequence with the 3'-guanine mutated. It was seen that MMS, which has the highest Swain-Scott substrate constant, yielded the widest array of mutational types. As the substrate constants decreased, the types of mutations became more and more restricted to the G.C----A.T transitions and the A.T----T.A transversions. The transitions are consistent with the concept that mutations arise from O6-alkylation of guanine and alkylation of thymine. The transversions are consistent with the notion of N1-alkylation of adenosine or adenylic acid.


Assuntos
Alquilantes/farmacologia , DNA Fúngico/efeitos dos fármacos , Mutagênicos/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Sequência de Bases , Análise Mutacional de DNA , Metanossulfonato de Etila/farmacologia , Etilnitrosoureia/farmacologia , Amplificação de Genes , Metanossulfonato de Metila/farmacologia , Metilnitrosoureia/farmacologia , Saccharomyces cerevisiae/genética
15.
Genetics ; 148(4): 1647-54, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9560384

RESUMO

Mutants of the HIS1 locus of the yeast Saccharomyces cerevisiae are suitable reporters for spontaneous reversion events because most reversions are topical, that is, within the locus itself. Thirteen mutations of his1-1 now have been identified with respect to base sequence. Revertants of three mutants and their spontaneous reversion rates are presented: (1) a chain termination mutation (his1-208, née his1-1) that does not revert by mutations of tRNA loci and reverts only by intracodonic suppression; (2) a missense mutation (his1-798, née his1-7) that can revert by intragenic suppression by base substitutions of any sort, including a back mutation as well as one three-base deletion; and (3) a -1 frameshift mutation (his1-434, née his1-19) that only reverts topically by +1 back mutation, +1 intragenic suppression, or a -2 deletion. Often the +1 insertion is accompanied by base substitution events at one or both ends of a run of A's. Missense suppressors of his1-798 are either feeders or nonfeeders, and at four different locations within the locus, a single base substitution encoding an amino acid alteration will suffice to turn the nonfeeder phenotype into a feeder phenotype. Late-appearing revertants of his1-798 were found to be slowly growing leaky mutants rather than a manifestation of adaptive mutagenesis. Spontaneous revertants of his1-208 and his1-434 produced no late-arising colonies.


Assuntos
Genes Fúngicos , Mutação , Saccharomyces cerevisiae/genética , Adenina , Guanina , Timina
16.
Gait Posture ; 22(2): 96-106, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16139744

RESUMO

We studied the reliability of different measures of the visual contribution to postural steadiness by recording the postural sway during standing with eyes open (EO) or eyes closed (EC). The COP trajectory was recorded in 21 subjects aged 42-61 standing on a firm or foam support. The improvement of postural steadiness due to vision was measured with a higher reliability (i.e. lower intra- and inter-subject variabilities) with the sway velocity V, than with the position RMS. Due to the increase of the variability of V and RMS with their own mean values, we quantified the visual contribution to posture by the stabilization ratio (SR), based on a logarithm transform of V or RMS. As compared to the Romberg quotient (EC/EO), SR improved the reliability of the measurement of the visual contribution to posture within individuals, across subjects, and even across different studies in the literature. Our method led to decrease the inter-subject coefficient of variation of this measurement to about 25%, using a foam support. It leads to a similar accuracy in binocular and monocular vision, and it also applies to the quantification of other non-visual sensory contributions to posture.


Assuntos
Movimento/fisiologia , Postura/fisiologia , Percepção Visual/fisiologia , Adulto , Humanos , Matemática , Pessoa de Meia-Idade , Modelos Teóricos
17.
Ann Acad Med Singap ; 34(1): 24-30, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15726216

RESUMO

INTRODUCTION: There is a worldwide pandemic of type 2 diabetes mellitus and approximately one-third of these individuals will develop diabetic nephropathy. Coupled with their increased risk for cardiovascular disease, these individuals pose an enormous economic and social burden to all countries. This review will discuss therapeutic strategies, aimed at control of blood pressure and proteinuria, to prevent or retard the development of diabetic nephropathy. METHODS: Studies that involved patients with type 2 diabetes with albuminuria (microalbuminuria or proteinuria) and/or hypertension and/or renal impairment were included in this review. The PubMed Medline database was used as the source of data. RESULTS: Blood pressure control is paramount in reducing cardiovascular risk and the development of diabetic nephropathy. The target blood pressure is <130/80 mm Hg in all patients with type 2 diabetes. Angiotensin receptor blockers (ARBs) are the preferred first-line agents while angiotensin-converting enzyme (ACE) inhibitors can be considered in those with microalbuminuria and normoalbuminuria. Reduction in proteinuria retards the progression of nephropathy and should be considered as a goal on its own. Dual therapy with an ACE inhibitor and ARB can be considered in patients with severe proteinuria or uncontrolled hypertension. CONCLUSION: Important strategies to prevent or retard the progression of diabetic nephropathy in type 2 diabetes include excellent blood pressure control with an aggressive approach to reduce microalbuminuria or proteinuria. The drugs of choice are the ARB and the ACE inhibitor.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Diabetes Mellitus Tipo 2/fisiopatologia , Nefropatias Diabéticas/prevenção & controle , Hipertensão/tratamento farmacológico , Proteinúria/tratamento farmacológico , Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Pressão Sanguínea/fisiologia , Monitorização Ambulatorial da Pressão Arterial , Diabetes Mellitus Tipo 2/urina , Nefropatias Diabéticas/fisiopatologia , Nefropatias Diabéticas/urina , Progressão da Doença , Quimioterapia Combinada , Humanos , Hipertensão/etiologia , Guias de Prática Clínica como Assunto , Proteinúria/etiologia
18.
Phytomedicine ; 22(6): 621-30, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-26055127

RESUMO

BACKGROUND: 6-Shogaol, one of the main bioactive constituents of Zingiber officinale has been shown to possess various therapeutic properties. Interaction of a therapeutic compound with plasma proteins greatly affects its pharmacokinetic and pharmacodynamic properties. PURPOSE: The present investigation was undertaken to characterize the interaction between 6-shogaol and the main in vivo transporter, human serum albumin (HSA). METHODS: Various binding characteristics of 6-shogaol-HSA interaction were studied using fluorescence spectroscopy. Thermal stability of 6-shogaol-HSA system was determined by circular dichroism (CD) and differential scanning calorimetric (DSC) techniques. Identification of the 6-shogaol binding site on HSA was made by competitive drug displacement and molecular docking experiments. RESULTS: Fluorescence quench titration results revealed the association constant, Ka of 6-shogaol-HSA interaction as 6.29 ± 0.33 × 10(4) M(-1) at 25 ºC. Values of the enthalpy change (-11.76 kJ mol(-1)) and the entropy change (52.52 J mol(-1) K(-1)), obtained for the binding reaction suggested involvement of hydrophobic and van der Waals forces along with hydrogen bonds in the complex formation. Higher thermal stability of HSA was noticed in the presence of 6-shogaol, as revealed by DSC and thermal denaturation profiles. Competitive ligand displacement experiments along with molecular docking results suggested the binding preference of 6-shogaol for Sudlow's site I of HSA. CONCLUSION: All these results suggest that 6-shogaol binds to Sudlow's site I of HSA through moderate binding affinity and involves hydrophobic and van der Waals forces along with hydrogen bonds.


Assuntos
Catecóis/química , Albumina Sérica/química , Zingiber officinale/química , Sítios de Ligação , Varredura Diferencial de Calorimetria , Dicroísmo Circular , Temperatura Alta , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Espectrometria de Fluorescência , Termodinâmica
19.
Transplant Proc ; 47(3): 775-9, 2015 04.
Artigo em Inglês | MEDLINE | ID: mdl-25891729

RESUMO

Porcine embryonic stem cells (ES) are considered attractive preclinical research tools for human liver diseases. Although several studies previously reported generation of porcine ES, none of these studies has described hepatic differentiation from porcine ES. The aim of this study was to generate hepatocytes from porcine ES and analyze their characteristics. We optimized conditions for definitive endoderm induction and developed a 4-step hepatic differentiation protocol. A brief serum-free condition with activin A efficiently induced definitive endoderm differentiation from porcine ES. The porcine ES-derived hepatocyte-like cells highly expressed hepatic markers including albumin and α-fetoprotein, and displayed liver characteristics such as glycogen storage, lipid production, and low-density lipoprotein uptake. For the first time, we describe a highly efficient protocol for hepatic differentiation from porcine ES. Our findings provide valuable information for translational liver research using porcine models, including hepatic regeneration and transplant studies, drug screening, and toxicology.


Assuntos
Diferenciação Celular , Células-Tronco Embrionárias/fisiologia , Hepatócitos/fisiologia , Modelos Animais , Albuminas/metabolismo , Animais , Biomarcadores/metabolismo , Hepatócitos/transplante , Suínos , alfa-Fetoproteínas/metabolismo
20.
Int J Tuberc Lung Dis ; 19(9): 1102-8, i-ii, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26260833

RESUMO

SETTING: Conventional diagnostic methods for tuberculosis (TB) have limited sensitivity and specificity or are time-consuming. OBJECTIVE: 16S rDNA and 16S rRNA of Mycobacterium tuberculosis complex (MTC) were used as targets to develop sensitive and specific polymerase chain reactions (PCRs) to improve the diagnosis of MTC. DESIGN: We developed conventional and real-time PCRs targeting 16S rDNA and rRNA of MTC. RESULTS: PCRs targeting 16S rRNA had a 10-100 times lower limit of detection for M. tuberculosis than PCRs targeting 16S rDNA. The sensitivities of the 16S rDNA PCR, 16S rRNA reverse transcription PCR (RT-PCR), 16S rDNA real-time PCR and 16S rRNA real-time RT-PCR for sputum specimens were respectively 92%, 94.6%, 96% and 100%. Real-time PCR showed no cross-reactivity, but conventional PCR had cross-reactivity to M. avium, M. gastri and M. nonchromogenicum. CONCLUSION: PCRs targeting the 16S rRNA of MTC were more sensitive than those targeting 16S rDNA; 16S rRNA real-time RT-PCR showed the highest sensitivity and specificity for MTC.


Assuntos
Técnicas Bacteriológicas/métodos , Mycobacterium tuberculosis/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/métodos , Escarro/microbiologia , Tuberculose/diagnóstico , Humanos , Mycobacterium tuberculosis/genética , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Sensibilidade e Especificidade
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