Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 365
Filtrar
1.
Int J Obes (Lond) ; 45(1): 45-55, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32884101

RESUMO

BACKGROUND/OBJECTIVES: In Samoa, where 80% of the adult population is living with obesity, understanding the determinants of adiposity and growth during infancy may inform prevention efforts. We examined the association of a missense variant, rs373863828, in the CREBRF gene with body composition in Samoan infants. Adults with one or more copies of the rs373863828 minor allele (A) have higher odds of obesity, based on body-mass index (BMI), but paradoxically decreased odds of diabetes compared to those without the allele. Our study may offer novel insight into the natural history and pathogenesis of this unexpected relationship. SUBJECTS/METHODS: In a prospective study, we measured body composition in early infancy, and at 2- and 4-months of age using anthropometry and dual-energy x-ray absorptiometry (DXA). We genotyped subjects at the CREBRF rs373863828 locus and compared infants with (AA/AG) and without (GG) the variant. In longitudinal analyses, we calculated the absolute change in each outcome from the early infant to the 4-month assessment, adjusting for baseline and other covariates. RESULTS: In cross-sectional analyses, there was no significant difference in infant BMI or fat mass by genotype. After adjusting for covariates, infants with the variant had 4.0 ± 1.8 g more bone mass (p = 0.026) and 210.9 ± 79.6 g more lean mass (p = 0.009) at 4-months and accumulated 176.9 ± 73.0 g more lean mass between the early infant and 4-month assessment (p = 0.017). CONCLUSIONS: The CREBRF rs373863828 minor allele (A) was not associated with increased BMI or adiposity in Samoan infants, but instead with increased lean and bone mass. Our findings suggest that lean (i.e., muscle) and bone mass accretion should be explored as pathways to explain the "protective" effect of the CREBRF variant against diabetes.


Assuntos
Composição Corporal/genética , Mutação de Sentido Incorreto/genética , Havaiano Nativo ou Outro Ilhéu do Pacífico , Proteínas Supressoras de Tumor/genética , Adulto , Estudos Transversais , Feminino , Genótipo , Humanos , Lactente , Recém-Nascido , Masculino , Havaiano Nativo ou Outro Ilhéu do Pacífico/genética , Havaiano Nativo ou Outro Ilhéu do Pacífico/estatística & dados numéricos , Polimorfismo de Nucleotídeo Único/genética , Estudos Prospectivos , Samoa/epidemiologia , Adulto Jovem
2.
Opt Express ; 27(24): 35689-35699, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31878736

RESUMO

Optically pumped rare gas laser performance is analyzed as a function of the Ar(3p54p; 2p) + M → Ar(3p54s; 1s) + M branching ratios. Due to the uncertainty in the branching ratios, a sensitivity study is performed to determine the effect on output and absorbed pump laser intensities. The analysis is performed using a radio frequency dielectric barrier discharge as the source of metastable production for a variety of Argon in Helium mixtures over pressures ranging from 200 to 500 Torr. Peak output laser intensities show a factor of 7 increase as the branching ratio is increased from 0.25 to 1.00. The collection of Ar* in Ar(1s4) is inversely proportional to the branching ratio and decreases output laser intensity by reducing the density of species directly involved with lasing.

3.
Am J Transplant ; 16(2): 497-508, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26663361

RESUMO

T cell suppression prevents acute cellular rejection but causes life-threatening infections and malignancies. Previously, liver transplant (LTx) rejection in children was associated with the single-nucleotide polymorphism (SNP) rs9296068 upstream of the HLA-DOA gene. HLA-DOA inhibits B cell presentation of antigen, a potentially novel antirejection drug target. Using archived samples from 122 white pediatric LTx patients (including 77 described previously), we confirmed the association between rs9296068 and LTx rejection (p = 0.001, odds ratio [OR] 2.55). Next-generation sequencing revealed that the putative transcription factor (CCCTC binding factor [CTCF]) binding SNP locus rs2395304, in linkage disequilibrium with rs9296068 (D' 0.578, r(2) = 0.4), is also associated with LTx rejection (p = 0.008, OR 2.34). Furthermore, LTx rejection is associated with enhanced B cell presentation of donor antigen relative to HLA-nonidentical antigen in a novel cell-based assay and with a downregulated HLA-DOA gene in a subset of these children. In lymphoblastoid B (Raji) cells, rs2395304 coimmunoprecipitates with CTCF, and CTCF knockdown with morpholino antisense oligonucleotides enhances alloantigen presentation and downregulates the HLA-DOA gene, reproducing observations made with HLA-DOA knockdown and clinical rejection. Alloantigen presentation is suppressed by inhibitors of methylation and histone deacetylation, reproducing observations made during resolution of rejection. Enhanced donor antigen presentation by B cells and its epigenetic dysregulation via the HLA-DOA gene represent novel opportunities for surveillance and treatment of transplant rejection.


Assuntos
Apresentação de Antígeno/imunologia , Linfócitos B/imunologia , Epigenômica , Rejeição de Enxerto/etiologia , Antígenos HLA/genética , Isoantígenos/imunologia , Transplante de Fígado/efeitos adversos , Western Blotting , Células Cultivadas , Criança , Imunoprecipitação da Cromatina , Feminino , Seguimentos , Genótipo , Rejeição de Enxerto/patologia , Sobrevivência de Enxerto , Humanos , Técnicas Imunoenzimáticas , Hepatopatias/cirurgia , Masculino , Polimorfismo de Nucleotídeo Único/genética , Complicações Pós-Operatórias , Prognóstico , Estudos Prospectivos , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Risco , Doadores de Tecidos
4.
N Z Vet J ; 64(5): 282-7, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27256490

RESUMO

AIM: To assess the effect of sedation and local anaesthesia (LA) at disbudding, and the addition of meloxicam or ketoprofen treatment, on weight gain in dairy calves following disbudding. METHODS: Friesian-Jersey cross calves, from four dairy farms, were enrolled when 3-6 weeks old. All calves (n=271) were disbudded by veterinary personnel and randomly assigned to six groups: 136 were disbudded without sedation or LA, of which 31 received 20 mg meloxicam S/C and 75 received 150 mg ketoprofen I/M. A further 135 were disbudded with sedation (0.25 mg/kg xylazine I/M) and LA, of which 30 also received meloxicam and 75 received ketoprofen. Calves were weighed 3 days before, and 15 and 30 days after, disbudding (Day 0). Daily weight gain was analysed using mixed models and ANOVA. RESULTS: Complete results were obtained from 263 calves. From Day -3 to Day 15, the growth rate of calves disbudded without pain relief (0.53 (95% CI=0.47-0.60) kg/day) was less that of calves disbudded with some form of pain relief (0.65 (95% CI=0.62-0.68) kg/d; p=0.004). There was no difference between the effect of meloxicam or ketoprofen (p=1.00). An interaction between use of sedation and LA and additional non-steroidal anti-inflammatory drugs (NSAID) meant that NSAID treatment did not increase growth rates in calves disbudded with sedation and LA but did increase growth rates for calves disbudded without pain relief (p<0.05). From Day 16 to Day 30 there was no effect of NSAID treatment on growth rate, but calves receiving LA and sedation grew faster (0.74 (95% CI=0.69-0.80) kg/day) than calves disbudded without LA and sedation (0.66 (95% CI=0.61-0.71) kg/day; p=0.018). From Day -3 to Day 30, calves disbudded with sedation and LA grew faster (0.71 (95%CI=0.64-0.77) kg/day) than calves disbudded without sedation and LA (0.60 (95% CI=0.55-0.65) kg/day; p=0.011). However, addition of NSAID to sedation and LA made no further difference to growth rates (p=0.69). CONCLUSIONS: Dairy calves disbudded with no pain relief had slower growth rates than calves receiving pain relief. From Day 15 to 30 calves given no pain relief, or NSAID alone, grew more slowly than those receiving sedation and LA at disbudding. The addition of NSAID treatment to sedation and LA did not further increase growth rates. CLINICAL RELEVANCE: This study adds to the evidence that pain management when disbudding is beneficial for calf productivity as well as calf welfare.


Assuntos
Anestesia Local/veterinária , Anti-Inflamatórios não Esteroides/uso terapêutico , Bovinos/crescimento & desenvolvimento , Cornos/cirurgia , Hipnóticos e Sedativos/uso terapêutico , Anestesia Local/métodos , Animais , Bovinos/cirurgia , Sedação Consciente/métodos , Sedação Consciente/veterinária , Indústria de Laticínios/métodos , Feminino , Cetoprofeno/uso terapêutico , Meloxicam , Tiazinas/uso terapêutico , Tiazóis/uso terapêutico , Aumento de Peso , Xilazina/uso terapêutico
5.
Caries Res ; 48(4): 330-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24556642

RESUMO

Dental caries continues to be the most common chronic disease in children today. Despite the substantial involvement of genetics in the process of caries development, the specific genes contributing to dental caries remain largely unknown. We performed separate genome-wide association studies of smooth and pit-and-fissure tooth surface caries experience in the primary dentitions of self-reported white children in two samples from Iowa and rural Appalachia. In total, 1,006 children (ages 3-12 years) were included for smooth surface analysis, and 979 children (ages 4-14 years) for pit-and-fissure surface analysis. Associations were tested for more than 1.2 million single nucleotide polymorphisms, either genotyped or imputed. We detected genome-wide significant signals in KPNA4 (p value = 2.0E-9), and suggestive signals in ITGAL (p value = 2.1E-7) and PLUNC family genes (p value = 2.0E-6), thus nominating these novel loci as putative caries susceptibility genes. We also replicated associations observed in previous studies for MPPED2 (p value = 6.9E-6), AJAP1 (p value = 1.6E-6) and RPS6KA2 (p value = 7.3E-6). Replication of these associations in additional samples, as well as experimental studies to determine the biological functions of associated genetic variants, are warranted. Ultimately, efforts such as this may lead to a better understanding of caries etiology, and could eventually facilitate the development of new interventions and preventive measures.


Assuntos
Cárie Dentária/genética , Fissuras Dentárias/genética , Dente Decíduo/patologia , Adolescente , Região dos Apalaches , Antígeno CD11a/genética , Moléculas de Adesão Celular/genética , Criança , Pré-Escolar , Mapeamento Cromossômico , Cromossomos Humanos Par 18/genética , Cromossomos Humanos Par 3/genética , Cromossomos Humanos X/genética , Índice CPO , Feminino , Predisposição Genética para Doença/genética , Variação Genética/genética , Estudo de Associação Genômica Ampla , Genótipo , Glicoproteínas/genética , Humanos , Iowa , Zíper de Leucina/genética , Sistema de Sinalização das MAP Quinases/genética , Masculino , Fosfoproteínas/genética , Diester Fosfórico Hidrolases/genética , Polimorfismo de Nucleotídeo Único/genética , Proteínas Quinases S6 Ribossômicas 90-kDa/genética , alfa Carioferinas/genética
6.
Heliyon ; 10(6): e27783, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38524528

RESUMO

Degradation of insulation paper is a key contributor to the failure of power transformers. Insulation degradation accelerates at elevated temperatures, which highlights the potential for better thermal management to prolong life. While several studies have analyzed the benefits of high thermal conductivity oil for reducing temperatures inside a transformer, this study is an initial assessment of the benefits of high thermal conductivity paper on transformer life. Blending particulates with cellulosic fibers offers a pathway for high thermal conductivity paper (with good dielectric properties), which can reduce internal temperatures. Presently, life extensions that can be achieved by the use of such thermally conducting papers were estimated, with the thermal conductivity of the paper being the key parameter under study. The analytical-numerical thermal model used in this study was validated against experimental measurements in a distribution transformer, adding confidence to the utility of the model. This model was then used to provide estimates of hot-spot temperature reduction resulting from the use of papers with higher thermal conductivity than baseline. Transformer life was predicted conventionally by tracking the degree of polymerization of paper over time, based on an Arrhenius model. Results indicate that increasing the thermal conductivity of paper from 0.2 W/mK (baseline) to 1 W/mK reduces the hot spot temperature by 10 °C. While degradation significantly depends on the moisture and oxygen content, the model shows that such a temperature reduction can increase life for all conditions, by as much as a factor of three.

7.
Nat Genet ; 11(4): 402-8, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7493020

RESUMO

As genetic marker maps have improved, multipoint linkage analysis has become a crucial part of all disease mapping studies. Paradoxically, multipoint lod scores become increasingly difficult to compute, particularly as the numbers of markers, marker alleles and untyped people increase. We have solved this problem by using a novel set-recording scheme to recode each person's genotype and 'fuzzy inheritance' to infer transmission probabilities. Our approach is implemented in a memory-efficient computer program, VITESSE, for extremely rapid computation of exact multipoint likelihoods. VITESSE enables fast and precise multipoint mapping of disease loci with highly polymorphic markers.


Assuntos
Algoritmos , Mapeamento Cromossômico/métodos , Genótipo , Software , Feminino , Ligação Genética , Marcadores Genéticos , Humanos , Funções Verossimilhança , Masculino , Linhagem
8.
Nat Genet ; 5(4): 386-91, 1993 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8298648

RESUMO

Dopa-responsive dystonia (DRD) is an autosomal-dominant neurological disorder which appears to result from a genetically determined deficiency of striatal dopamine. Pathological evidence suggests that this may be due to the establishment of a reduced number of dopaminergic nerve terminals in the striatum, or to an excessive reduction (pruning) of these terminals in early development. We have mapped the DRD gene to chromosome 14 by linkage analysis in 3 families with a maximum 2-point lod score of 4.67 at 8.6 centiMorgans from D14S63; maximum multipoint lod scores > 6 were obtained for the intervals D14S47-D14S52 and D14S52-D14S63. The flanking loci D14S47 and D14S63 define a region of about 22 cM as containing the DRD gene.


Assuntos
Cromossomos Humanos Par 14 , Di-Hidroxifenilalanina/deficiência , Distonia/genética , Escore Lod , Mapeamento Cromossômico , Distonia/patologia , Família , Feminino , Ligação Genética , Genótipo , Humanos , Masculino , Linhagem
9.
Nat Genet ; 13(1): 70-7, 1996 May.
Artigo em Inglês | MEDLINE | ID: mdl-8673107

RESUMO

Terminal keratinocyte differentiation involves coordinated expression of several functionally interdependent genes, many of which have been mapped to the epidermal differentiation complex (EDC) on chromosome 1q21. We have identified linkage of Vohwinkel's syndrome in an extended pedigree to markers flanking the EDC region with a maximum multipoint lod score of 14.3. Sequencing of the loricrin gene revealed an insertion that shifts the translation frame of the C-terminal Gly- and Gln/Lys-rich domains, and is likely to impair cornification. Our findings provide the first evidence for a defect in an EDC gene in human disease, and disclose novel insights into perturbations of cornified cell envelope formation.


Assuntos
Cromossomos Humanos Par 1 , Ceratodermia Palmar e Plantar/genética , Proteínas de Membrana/genética , Mutação , Sequência de Aminoácidos , Sequência de Bases , Membrana Celular/metabolismo , Mapeamento Cromossômico , Primers do DNA , Elementos de DNA Transponíveis , Feminino , Ligação Genética , Marcadores Genéticos , Humanos , Queratinócitos/metabolismo , Ceratodermia Palmar e Plantar/patologia , Escore Lod , Masculino , Dados de Sequência Molecular , Linhagem , Reação em Cadeia da Polimerase , Biossíntese de Proteínas , Pele/patologia , Pele/ultraestrutura , Síndrome
10.
Nat Genet ; 4(4): 351-6, 1993 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8401581

RESUMO

Hirschsprung disease (HSCR) is characterized by a congenital absence of enteric ganglia along a variable length of the intestine. Although long considered to be a multifactorial disease, we have identified linkage in a subset of five HSCR families to the pericentromeric region of chromosome 10, thereby providing monogenic inheritance in some families. A maximum two-point lod score of 3.37 (theta = 0.045) was observed between HSCR and D10S176, under an incompletely penetrant dominant model. Multipoint, affecteds-only and non-parametric analyses supported this finding and localize this gene to a region of approximately 7 centiMorgans, in close proximity to the locus for multiple endocrine neoplasia type 2 (MEN2). The co-occurrence of these two entities in some families might be attributable to shared pathogenetic origins.


Assuntos
Centrômero , Cromossomos Humanos Par 10 , Doença de Hirschsprung/genética , Alelos , Mapeamento Cromossômico , Família , Feminino , Ligação Genética , Marcadores Genéticos , Genótipo , Humanos , Masculino , Linhagem
11.
Science ; 202(4366): 440-2, 1978 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-568309

RESUMO

Amiprophos methyl (APM) is a strong, readily reversible and highly selective inhibitor of tubulin synthesis in Chlamydomonas reinhardi. The extensive induction of tubulin synthesis that accompanies flagellar regeneration in this organism is prevented by 3 to 10 micrometerAPM. When applied after induction has begun, APM causes a rapid cessation of tubulin synthesis. Translation studies in vitro indicate that the lack of tubulin production in APM-treated cells is not due to a direct inhibition of tubulin messenger RNA translation but rather to a selective depletion of tubulin messenger RNA.


Assuntos
Glicoproteínas/biossíntese , Compostos Organotiofosforados/farmacologia , Tubulina (Proteína)/biossíntese , Chlamydomonas/ultraestrutura , Depressão Química , Feminino , Flagelos/fisiologia , Flagelos/ultraestrutura , Biossíntese de Proteínas , Regeneração/efeitos dos fármacos , Zigoto/metabolismo
12.
Science ; 167(3926): 1735-6, 1970 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-5416539

RESUMO

In extracts of wheat embryo, aurintricarboxylic acid inhibits attachment of ribosomes to messenger RNA and has little effect on aminoacyl transfer to peptide. This specificity of inhibition allows (i) the demonstration that the initial phase of amino acid incorporation dependent on RNA of tobacco mosaic virus involves an "initiation" reaction between ribosome and messenger RNA which requires two soluble factors, (ii) an assay facilitating purification of the initiation factors, and (iii) the demonstration that these factors are distinct from aminoacyl transfer enzymes.


Assuntos
Ácidos Cicloexanocarboxílicos/farmacologia , RNA Mensageiro/metabolismo , Ribossomos/metabolismo , Triticum/metabolismo , Aminoácidos/metabolismo , Isótopos de Carbono , Depressão Química , Biossíntese Peptídica , RNA Viral/metabolismo , Ribossomos/efeitos dos fármacos , Vírus do Mosaico do Tabaco , Transferases , Triticum/citologia , Triticum/efeitos dos fármacos
13.
Science ; 290(5500): 2312-5, 2000 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-11125147

RESUMO

The TATA-binding protein (TBP) is believed to function as a key component of the general transcription machinery. We tested the role of TBP during the onset of embryonic transcription by antisense oligonucleotide-mediated turnover of maternal TBP messenger RNA. Embryos without detectable TBP initiated gastrulation but died before completing gastrulation. The expression of many genes transcribed by RNA polymerase II and III was reduced; however, some genes were transcribed with an efficiency identical to that of TBP-containing embryos. Using a similar antisense strategy, we found that the TBP-like factor TLF/TRF2 is essential for development past the mid-blastula stage. Because TBP and a TLF factor play complementary roles in embryonic development, our results indicate that although similar mechanistic roles exist in common, TBP and TLF function differentially to control transcription of specific genes.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Embrião não Mamífero/metabolismo , Desenvolvimento Embrionário , Regulação da Expressão Gênica no Desenvolvimento , Fatores de Transcrição/metabolismo , Transcrição Gênica , Animais , Blastocisto/metabolismo , Proteínas de Ligação a DNA/genética , Gástrula/metabolismo , Oligonucleotídeos Antissenso/metabolismo , Oligonucleotídeos Antissenso/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteína de Ligação a TATA-Box , Proteína 2 de Ligação a Repetições Teloméricas , Fatores de Transcrição/genética , Xenopus/embriologia
14.
Science ; 287(5452): 482-5, 2000 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-10642549

RESUMO

Acidic media trigger cytoplasmic urease activity of the unique human gastric pathogen Helicobacter pylori. Deletion of ureI prevents this activation of cytoplasmic urease that is essential for bacterial acid resistance. UreI is an inner membrane protein with six transmembrane segments as shown by in vitro transcription/translation and membrane separation. Expression of UreI in Xenopus oocytes results in acid-stimulated urea uptake, with a pH profile similar to activation of cytoplasmic urease. Mutation of periplasmic histidine 123 abolishes stimulation. UreI-mediated transport is urea specific, passive, nonsaturable, nonelectrogenic, and temperature independent. UreI functions as a H+-gated urea channel regulating cytoplasmic urease that is essential for gastric survival and colonization.


Assuntos
Proteínas de Bactérias/metabolismo , Helicobacter pylori/metabolismo , Proteínas de Membrana Transportadoras , Estômago/microbiologia , Ureia/metabolismo , Urease/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Transporte Biológico , Membrana Celular/química , Permeabilidade da Membrana Celular , Citoplasma/enzimologia , Citoplasma/metabolismo , Ativação Enzimática , Ácido Gástrico , Glicosilação , Helicobacter pylori/enzimologia , Helicobacter pylori/crescimento & desenvolvimento , Histidina/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Oócitos/enzimologia , Proteínas Recombinantes/metabolismo , Temperatura , Xenopus
15.
Ann Hum Genet ; 72(Pt 6): 780-92, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18616661

RESUMO

We conducted a genome-wide scan in 46 pedigrees, with 671 phenotyped adults, from the independent nation of Samoa to map quantitative trait loci (QTLs) for adiposity-related phenotypes, including body mass index (BMI), abdominal circumference (ABDCIR), percent body fat (%BFAT), and fasting serum leptin and adiponectin. A set of 378 autosomal and 14 X chromosomal microsatellite markers were genotyped in 572 of the adults. Significant genetic correlations (0.82-0.96) were detected between pairs of BMI, ABDCIR, %BFAT and leptin. Suggestive linkages were found on 13q31 (LOD = 2.30 for leptin, LOD = 2.48 for %BFAT, LOD = 2.04 for ABDCIR, and LOD = 2.09 for BMI) and on 9p22 (LOD = 3.08 for ABDCIR and LOD = 2.53 for %BFAT). Furthermore, bivariate linkage analyses indicated that the genetic regions on 9p22 (bivariate LOD 2.35-3.10, LOD(eq) (1df) 1.88-2.59) and 13q31 (bivariate LOD 1.96-2.64, LOD(eq) 1.52-2.21) might harbor common major genes with pleiotropic effects. Other regions showing suggestive linkage included 4q22 (LOD = 2.95) and 7p14 (LOD = 2.64) for %BFAT, 2q13 for adiponectin (LOD = 2.05) and 19q12 for BMI-adjusted leptin (LOD = 2.03). Further fine mapping of these regions may help identify the genetic variants contributing to the development of obesity in Samoan adults.


Assuntos
Adiposidade/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Predisposição Genética para Doença , Genoma Humano , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/genética , Linhagem , Samoa
16.
Int J Hyperthermia ; 24(4): 337-45, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18465418

RESUMO

In magnetic nanoparticle hyperthermia for cancer treatment, controlling the heat distribution and temperature elevations is an immense challenge in clinical applications. In this study we evaluate magnetic nanofluid transport and heat distribution induced by commercially available magnetic nanoparticles injected into the extracellular space of biological tissue using agarose gel with porous structures similar to human tissue. The nanofluid distribution in the gel is examined via digital images of the nanofluid spreading in the gel. A radio-frequency electromagnetic field is applied to the gel following the nanofluid injection and the initial rates of temperature rise at various locations are measured to obtain the specific absorption rate (SAR) distribution. By adjusting the gel concentration and injection flow rate, the results have demonstrated that a relatively low injection rate leads to a spherically shaped nanofluid distribution in the gels which is desirable for controlling temperature elevations. The SAR distribution shows that the nanoparticle distribution in the gel is not uniform with a high concentration of the nanoparticles close to the injection site. We believe that the experimental study is the first step towards providing guidance for designing better treatment protocol for future clinical applications.


Assuntos
Magnetismo , Nanopartículas , Neoplasias/terapia , Humanos , Sefarose
17.
Trends Genet ; 11(12): 513-9, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8533170

RESUMO

Improved genotyping technology has made it feasible to use a genetic approach to map genes involved in the etiology of common human diseases. We discuss here recent developments in several different statistical approaches to linkage analysis of these traits, including affected-sib-pair methods, the affected-pedigree-member method, regressive models and linkage-disequilibrium-based approaches. We discuss advantages and disadvantages of the various approaches, as well as factors influencing study design and the ability to detect loci. Statistical methodology in this area is advancing rapidly and will help enable the mapping and cloning of loci involved in susceptibility to common multifactorial diseases.


Assuntos
Cromossomos Humanos , Doenças Genéticas Inatas/genética , Ligação Genética , Modelos Genéticos , Transtorno Autístico/epidemiologia , Transtorno Autístico/genética , Mapeamento Cromossômico , Feminino , Humanos , Desequilíbrio de Ligação , Masculino , Núcleo Familiar , Linhagem
18.
Mol Cell Biol ; 3(7): 1222-34, 1983 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-6888379

RESUMO

A product of the adenovirus E1A gene is a positive regulator of early viral gene expression. In this report we show that E1A regulates at the transcriptional level and that sequences located 5' to the early viral regions contain sites which confer regulation by the E1A gene product. We constructed chimeric genes in which the sequences at the 5' end of the E2A, E3, and E4 regions were fused to the structural sequences of either the herpes simplex virus thymidine kinase gene, the bacterial gene encoding the enzyme neomycin phosphotransferase, or the chloramphenicol acetyltransferase gene. In all cases, expression of the chimeric genes was induced by a product of the E1A region. It was also found that the insertion of a fragment from the left-hand end of the adenovirus type 5 genome into a plasmid harboring the thymidine kinase gene resulted in elevated frequencies of transformation of TK- cells to TK+. The elevated transformation frequencies were only detected when the insert and tk gene were covalently joined. This effect occurred even when the insert was several kilobase upstream from, and regardless of its orientation to, the transcriptional initiation site of the tk gene. We propose that this region of the adenovirus type 5 genome harbors a cis-acting enhancer of transcription.


Assuntos
Adenoviridae/genética , Regulação da Expressão Gênica , Genes Virais , Transcrição Gênica , Sequência de Bases , Quimera , DNA Recombinante , DNA Viral/genética , Genes , Humanos , Óperon , Plasmídeos , Timidina Quinase/genética
19.
Mol Cell Biol ; 3(12): 2131-42, 1983 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-6318084

RESUMO

The regulation of adenovirus type 5 gene expression by the E1a gene product was examined in microinjected Xenopus laevis oocytes. Chimeric genes were constructed which included the promoter region of early adenovirus type 5 gene 3 and the structural sequence which codes for the bacterial enzyme chloramphenicol-3-O-acetyltransferase (CAT). A plasmid containing this chimeric gene as well as plasmids containing the E1a gene were coinjected into oocyte nuclei. The presence of the E1a gene was shown to increase CAT activity by up to 8.5-fold over basal levels. Synthesis of the functional product from the E1a gene requires the removal of intron sequences by RNA splicing. The E1a gene and a derivative that precisely lacks the intron were equally effective in increasing CAT activity, suggesting that splicing of the primary E1a transcript is efficiently accomplished in the oocyte nucleus. This was confirmed by directly examining the E1a mRNAs by the S1 mapping procedure. A protein extract from adenovirus type 5-infected HeLa cells enriched for the E1a protein may supplant the E1a plasmid in enhancing CAT activity. Synthesis of the CAT enzyme after gene injection is invariant in oocytes from the same frog, but oocytes from different frogs show a high degree of variability in their ability to synthesize the CAT enzyme. Microinjected X. laevis oocytes appear to be an extremely useful system to study the effects of protein elements on transcription.


Assuntos
Acetiltransferases/genética , Adenovírus Humanos/genética , Genes Virais , Genes , Oócitos/metabolismo , Transcrição Gênica , Adenovírus Humanos/enzimologia , Animais , Sequência de Bases , Cloranfenicol O-Acetiltransferase , Enzimas de Restrição do DNA , Feminino , Cinética , Microinjeções , Plasmídeos , Xenopus
20.
Mol Cell Biol ; 4(6): 1115-24, 1984 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-6738533

RESUMO

The 5' coding and promoter regions of the four coordinately regulated tubulin genes of Chlamydomonas reinhardi have been mapped and sequenced. DNA sequencing data shows that the predicted N-terminal amino acid sequences of Chlamydomonas alpha- and beta-tubulins closely match that of tubulins of other eucaryotes. Within the alpha 1- and alpha 2-tubulin gene set and the beta 1- and beta 2-tubulin gene set, both nucleotide sequence and intron placement are highly conserved. Transcription initiation sites have been located by primer extension analysis at 140, 141, 159, and 132 base pairs upstream of the translation initiator codon for the alpha 1-, alpha 2-, beta 1-, and beta 2-tubulin genes, respectively. Among the structures with potential regulatory significance, the most striking is a 16-base-pair consensus sequence [GCTC(G/C)AAGGC(G/T)(G/C)--(C/A)(C/A)G] which is found in multiple copies immediately upstream of the TATA box in each of the four genes. An unexpected discovery is the presence of pseudopromoter regions in two of the transcribed tubulin genes. One pseudopromoter region is located 400 base pairs upstream of the authentic alpha 2-tubulin gene promoter, whereas the other is located within the transcribed 5' noncoding region of the beta 1-tubulin gene.


Assuntos
Chlamydomonas/genética , Genes Reguladores , Genes , Óperon , Tubulina (Proteína)/genética , Sequência de Aminoácidos , Sequência de Bases , Chlamydomonas/metabolismo , Sequências Repetitivas de Ácido Nucleico , Transcrição Gênica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA