RESUMO
A case study into the preparation and physiological responses of competing in the Marathon des Sables (MDS) was conducted by preparing a male competitor for, and monitoring him during, his first attempt at the race. The aims of this case report were to (a) prepare and monitor an ex-Olympic, male rower (S1) during the 2010 race and; (b) compare his physiological responses and race performance to that of the current MDS record holder (S2). S1 (age 37 y; body mass 94.0 kg; height 1.92 m; VO(2peak) 66.0 ml·kg⻹·min⻹) and S2 (age 37 y; body mass 60.8 kg; height 1.68 m; VO(2peak) 65.9 ml·kg⻹·min⻹) completed a heat test and S1 subsequently underwent 7 d of heat acclimation prior to the MDS. Gastro-intestinal temperature (Tgi) and heart rate (HR) were measured for S1 during Stages 2, 4, and 5 of the MDS and pre- and post-stage body mass, and urine specific gravity were measured for all stages. Race time and average speeds were collected for S1 and S2. Total race times for S1 and S2 were 25:29:35 and 19:45:08 h:min:s. S1's mean (± 1 SD) percentage HR range (%HRR=[HR-HRmin]/[HRmax-HRmin]x100) was 66.1 ± 13.4% and Tgi ranged between 36.63-39.65°C. The results provide a case report on the physiological responses of a highly aerobically-trained, but novice ultra-endurance runner competing in the MDS, and allow for a comparison with an elite performer.
Assuntos
Condicionamento Físico Humano , Corrida/fisiologia , Adulto , Desempenho Atlético/fisiologia , Temperatura Corporal/fisiologia , Frequência Cardíaca/fisiologia , Temperatura Alta , Humanos , Masculino , Resistência Física/fisiologia , Aptidão Física/fisiologiaRESUMO
Mutations of the genes encoding APC or beta-catenin in colon carcinoma induce the constitutive formation of nuclear beta-catenin/Tcf-4 complexes, resulting in activated transcription of Tcf target genes. To study the physiological role of Tcf-4 (which is encoded by the Tcf7/2 gene), we disrupted Tcf7/2 by homologous recombination. Tcf7/2-/- mice die shortly after birth. A single histopathological abnormality was observed. An apparently normal transition of intestinal endoderm into epithelium occurred at approximately embryonic day (E) 14.5. However, no proliferative compartments were maintained in the prospective crypt regions between the villi. As a consequence, the neonatal epithelium was composed entirely of differentiated, non-dividing villus cells. We conclude that the genetic program controlled by Tcf-4 maintains the crypt stem cells of the small intestine. The constitutive activity of Tcf-4 in APC-deficient human epithelial cells may contribute to their malignant transformation by maintaining stem-cell characteristics.
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Intestino Delgado/citologia , Células-Tronco/citologia , Fatores de Transcrição/fisiologia , Animais , Endoderma/patologia , Células Epiteliais/citologia , Intestino Delgado/embriologia , Camundongos , Camundongos Knockout , Microvilosidades/ultraestrutura , Fatores de Transcrição TCF , Proteína 2 Semelhante ao Fator 7 de Transcrição , Fatores de Transcrição/análise , Fatores de Transcrição/genéticaRESUMO
The taxonomic status of two southern African coastal pipefish species, Syngnathus temminckii and Syngnathus watermeyeri, was investigated using a combination of morphological and genetic data. Morphological data showed that S. temminckii is distinct from the broadly distributed European pipefish Syngnathus acus, and a molecular phylogeny reconstructed using mitochondrial DNA recovered S. temminckii and S. watermeyeri as sister taxa. The southern African species share an evolutionary origin with north-eastern Atlantic Ocean and Mediterranean Sea species, including S. acus. These data support the existence of a distinct southern African clade of Syngnathus pipefishes that has diverged in situ to form the two species present in the region today.
Assuntos
Filogenia , Smegmamorpha/genética , África , Animais , Tamanho Corporal , DNA Mitocondrial/química , Funções Verossimilhança , Análise Multivariada , Análise de Sequência de DNA , Smegmamorpha/anatomia & histologia , Smegmamorpha/fisiologiaRESUMO
Combining DNA and superparamagnetic beads in a rotating magnetic field produces multiparticle aggregates that are visually striking, enabling label-free optical detection and quantification of DNA at levels in the picogram per microliter range. DNA in biological samples can be quantified directly by simple analysis of optical images of microfluidic wells placed on a magnetic stirrer without prior DNA purification. Aggregation results from DNA/bead interactions driven either by the presence of a chaotrope (a nonspecific trigger for aggregation) or by hybridization with oligonucleotides on functionalized beads (sequence-specific). This paper demonstrates quantification of DNA with sensitivity comparable to that of the best currently available fluorometric assays. The robustness and sensitivity of the method enable a wide range of applications, illustrated here by counting eukaryotic cells. Using widely available and inexpensive benchtop hardware, the approach provides a highly accessible low-tech microscale alternative to more expensive DNA detection and cell counting techniques.
Assuntos
DNA/sangue , Magnetismo/métodos , Imãs/química , Hibridização de Ácido Nucleico/métodos , DNA/análise , Humanos , Sensibilidade e EspecificidadeRESUMO
In this work, an mm-wave/THz MEMS switch design process is presented. The challenges and solutions associated with the switch electrical design, modeling, fabrication, and test are explored and discussed. To investigate the feasibility of this design process, the switches are designed on both silicon and fused quartz substrate and then tested in the 140-750 GHz frequency range. The measurement fits design expectations and simulation well. At 750 GHz the measurement results from switches on both substrates have an ON state insertion loss of less than 3 dB and an OFF state isolation larger than 12 dB.
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Gastric cancer is among the most prevalent and deadliest of cancers globally. To derive mechanistic insight into the pathways governing this disease, we generated a Claudin18-IRES-CreERT2 allele to selectively drive conditional dysregulation of the Wnt, Receptor Tyrosine Kinase and Trp53 pathways within the gastric epithelium. This resulted in highly reproducible metastatic, chromosomal-instable-type gastric cancer. In parallel, we developed orthotopic cancer organoid transplantation models to evaluate tumour-resident Lgr5+ populations as functional cancer stem cells via in vivo ablation. We show that Cldn18 tumours accurately recapitulate advanced human gastric cancer in terms of disease morphology, aberrant gene expression, molecular markers and sites of distant metastases. Importantly, we establish that tumour-resident Lgr5+ stem-like cells are critical to the initiation and maintenance of tumour burden and are obligatory for the establishment of metastases. These models will be invaluable for deriving clinically relevant mechanistic insights into cancer progression and as preclinical models for evaluating therapeutic targets.
Assuntos
Claudinas/genética , Células-Tronco Neoplásicas/patologia , Receptores Acoplados a Proteínas G/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Animais , Biomarcadores/metabolismo , Modelos Animais de Doenças , Mucosa Gástrica/patologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Organoides/transplante , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Proteínas Wnt/metabolismoRESUMO
Historical biogeography studies have at their disposal a small suite of vicariance models to explain genetic differentiation within and between species. One of these processes involves the role of river catchments and their associated watersheds, in driving diversification and is applicable to both aquatic and terrestrial organisms. Although the idea of catchments structuring the genetic history of aquatic organisms is reasonably well understood, their effect on terrestrial organisms has largely been overlooked, with relevant studies being limited in scope. South Africa presents a perfect test-bed for elucidating this mechanism of diversification due to its rich biodiversity, range of climatic environments and many large river catchments. Here we use the cicadas of the Platypleura plumosa complex to highlight the importance of catchments and their associated watersheds in driving diversification of terrestrial invertebrates that lack an aquatic life-stage. Population structure was found to correspond to primary and in some cases secondary catchments; highlighting the need to include information on catchment structure when formulating hypotheses of population diversification. Recognizing that climate change in the near future is likely to alter the environment, and particularly precipitation patterns, insight into recent patterns of population change related to catchments may be useful in a conservation context.
Assuntos
Ecossistema , Variação Genética , Hemípteros/genética , Filogenia , Animais , Teorema de Bayes , DNA Mitocondrial/genética , Hemípteros/classificação , Modelos Genéticos , Dinâmica Populacional , Análise de Sequência de DNA , África do Sul , Especificidade da EspécieRESUMO
The adenomatous polyposis coli (APC) tumor suppressor protein binds to beta-catenin, a protein recently shown to interact with Tcf and Lef transcription factors. The gene encoding hTcf-4, a Tcf family member that is expressed in colonic epithelium, was cloned and characterized. hTcf-4 transactivates transcription only when associated with beta-catenin. Nuclei of APC-/- colon carcinoma cells were found to contain a stable beta-catenin-hTcf-4 complex that was constitutively active, as measured by transcription of a Tcf reporter gene. Reintroduction of APC removed beta-catenin from hTcf-4 and abrogated the transcriptional transactivation. Constitutive transcription of Tcf target genes, caused by loss of APC function, may be a crucial event in the early transformation of colonic epithelium.
Assuntos
Neoplasias do Colo/genética , Proteínas do Citoesqueleto/metabolismo , Genes APC , Transativadores , Fatores de Transcrição/metabolismo , Ativação Transcricional , Proteína da Polipose Adenomatosa do Colo , Sequência de Aminoácidos , Animais , Linhagem Celular , Transformação Celular Neoplásica , Clonagem Molecular , Colo/metabolismo , Neoplasias do Colo/metabolismo , Proteínas do Citoesqueleto/genética , Regulação Neoplásica da Expressão Gênica , Genes Reporter , Humanos , Mucosa Intestinal/metabolismo , Camundongos , Dados de Sequência Molecular , Transdução de Sinais , Fatores de Transcrição TCF , Proteína 2 Semelhante ao Fator 7 de Transcrição , Fatores de Transcrição/química , Fatores de Transcrição/genética , Transfecção , Células Tumorais Cultivadas , beta CateninaRESUMO
Inactivation of the adenomatous polyposis coli (APC) tumor suppressor gene initiates colorectal neoplasia. One of the biochemical activities associated with the APC protein is down-regulation of transcriptional activation mediated by beta-catenin and T cell transcription factor 4 (Tcf-4). The protein products of mutant APC genes present in colorectal tumors were found to be defective in this activity. Furthermore, colorectal tumors with intact APC genes were found to contain activating mutations of beta-catenin that altered functionally significant phosphorylation sites. These results indicate that regulation of beta-catenin is critical to APC's tumor suppressive effect and that this regulation can be circumvented by mutations in either APC or beta-catenin.
Assuntos
Neoplasias do Colo/genética , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Genes APC , Transativadores , Fatores de Transcrição/metabolismo , Transcrição Gênica , Proteína da Polipose Adenomatosa do Colo , Neoplasias do Colo/metabolismo , Regulação Neoplásica da Expressão Gênica , Genes Reporter , Mutação em Linhagem Germinativa , Humanos , Mutação , Fosforilação , Transdução de Sinais , Fatores de Transcrição TCF , Proteína 2 Semelhante ao Fator 7 de Transcrição , Transfecção , Células Tumorais Cultivadas , beta CateninaRESUMO
Tcf transcription factors interact with beta-catenin and Armadillo to mediate Wnt/Wingless signaling. We now report the characterization of genes encoding two murine members of the Tcf family, mTcf-3 and mTcf-4. mTcf-3 mRNA is ubiquitously present in embryonic day 6.5 (E6.5) mouse embryos but gradually disappears over the next 3 to 4 days. mTcf-4 expression occurs first at E10.5 and is restricted to di- and mesencephalon and the intestinal epithelium during embryogenesis. The mTcf-3 and mTcf-4 proteins bind a canonical Tcf DNA motif and can complex with the transcriptional coactivator beta-catenin. Overexpression of Wnt-1 in a mammary epithelial cell line leads to the formation of a nuclear complex between beta-catenin and Tcf proteins and to Tcf reporter gene transcription. These data demonstrate a direct link between Wnt stimulation and beta-catenin/Tcf transcriptional activation and imply a role for mTcf-3 and -4 in early Wnt-driven developmental decisions in the mouse embryo.
Assuntos
Proteínas do Citoesqueleto/metabolismo , Proteínas HMGB , Proteínas Proto-Oncogênicas/metabolismo , Transdução de Sinais , Transativadores , Fatores de Transcrição/metabolismo , Proteínas de Peixe-Zebra , Células 3T3 , Sequência de Aminoácidos , Animais , Linhagem Celular , Núcleo Celular/metabolismo , Galinhas , Clonagem Molecular , Desenvolvimento Embrionário e Fetal , Expressão Gênica , Genes Reporter , Humanos , Luciferases/genética , Camundongos , Dados de Sequência Molecular , Células PC12 , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/genética , Ratos , Fatores de Transcrição TCF , Proteína 1 Semelhante ao Fator 7 de Transcrição , Proteína 2 Semelhante ao Fator 7 de Transcrição , Fatores de Transcrição/biossíntese , Ativação Transcricional , Proteínas Wnt , Proteína Wnt1 , beta CateninaRESUMO
BACKGROUND: Recurrent corneal erosion is a common cause of disabling ocular symptoms and predisposes the cornea to infection. It may follow corneal trauma. Measures to prevent the development of recurrent corneal erosion following corneal trauma have not been firmly established. Once recurrent corneal erosion develops simple medical therapy (standard treatment) may lead to resolution of the episode. However some patients continue to suffer when such therapy fails and once resolved further episodes of recurrent erosion may occur. A number of treatment and prophylactic options are then available but there is no agreement as to the best option. OBJECTIVES: To assess the effectiveness and safety of prophylactic and treatment regimens for recurrent corneal erosion. SEARCH STRATEGY: We searched CENTRAL, MEDLINE, EMBASE and LILACS in June 2007. The NRR was searched in April 2005. We also contacted researchers in the field. SELECTION CRITERIA: We included randomised and quasi-randomised trials that compared a prophylactic or treatment regimen with another prophylaxis/ treatment or no prophylaxis/ treatment for patients with recurrent corneal erosion. DATA COLLECTION AND ANALYSIS: Both authors independently extracted data and assessed trial quality. We contacted study authors for additional information. MAIN RESULTS: Five randomised and one quasi-randomised controlled trial were included in the review. The trials were heterogenous and of poor quality. Safety data presented were incomplete. For the treatment of recurrent corneal erosion there was limited evidence that oral tetracycline 250 mg twice daily for 12 weeks or topical prednisolone 0.5% four times daily for one week or both in addition to standard treatment; and excimer laser ablation in addition to mechanical debridement may be effective. Therapeutic contact lens wear was inferior to lubricant drops and ointment in abolishing the symptoms of recurrent corneal erosion and had a high complication rate. For prophylaxis of further episodes of recurrent corneal erosion there was no difference in the occurrence of objective signs of recurrent erosion between hypertonic saline ointment versus tetracycline ointment or lubricating ointment. Lubricating ointment at night in addition to standard treatment following traumatic corneal abrasion (erosion) caused by fingernail injury to prevent recurrence led to increased symptoms of recurrent corneal erosion compared to standard therapy alone. AUTHORS' CONCLUSIONS: Well-designed masked randomised controlled trials using standardised methods are needed to establish the benefits of new and existing prophylactic and treatment regimes for recurrent corneal erosion.
Assuntos
Doenças da Córnea/terapia , Lesões da Córnea , Antibacterianos/uso terapêutico , Lentes de Contato , Doenças da Córnea/prevenção & controle , Desbridamento/métodos , Glucocorticoides/uso terapêutico , Humanos , Prednisolona/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como Assunto , Prevenção Secundária , Tetraciclina/uso terapêuticoRESUMO
We propose Graphene Klein tunnel transistors (GKTFET) as a way to enforce current saturation while maintaining large mobility for high speed radio frequency (RF) applications. The GKTFET consists of a sequence of angled graphene p-n junctions (GPNJs). Klein tunneling creates a collimation of electrons across each GPNJ, so that the lack of substantial overlap between transmission lobes across successive junctions creates a gate-tunable transport gap without significantly compromising the on-current. Electron scattering at the device edge tends to bleed parasitic states into the gap, but the resulting pseudogap is still sufficient to create a saturated output (I D -V D ) characteristic and a high output resistance. The modulated density of states generates a higher transconductance (g m ) and unity current gain cut-off frequency (f T ) than GFETs. More significantly the high output resistance makes the unity power gain cut-off frequency (f max ) of GKTFETs considerably larger than GFETs, making analog GKTFET potentially useful for RF electronics. Our estimation shows the f T /f max of a GKTFET with 1 µm channel reaches 33 GHz/17 GHz, and scale up to 350 GHz/53 GHz for 100 nm channel (assuming a single, scalable trapezoidal gate). The f max of a GKTFET is 10 times higher than a GFET with the same channel length.
RESUMO
Participation of E-cadherin in the Wnt signaling pathway was suggested because of the dual role of beta-catenin in cell adhesion and the Wnt signaling cascade. Whereas beta-catenin interacts at the cell membrane with the cell adhesion protein E-cadherin, in the nucleus it activates Wnt target genes through formation of transcriptionally active complexes with members of the Tcf/Lef family of transcription factors. Here, we analyzed by PCR and direct cycle sequencing 26 human breast cancer cell lines for alterations in the E-cadherin gene. Genetic alterations were identified in eight cell lines. Five cell lines had truncating mutations, whereas three cell lines had in-frame deletions in the gene transcript and expressed mutant E-cadherin proteins at the cell membrane. Involvement of E-cadherin in the Wnt pathway was evaluated through determination of the activity of a Tcf reporter gene, which had been transiently transfected into 15 breast cancer cell lines. None of six E-cadherin mutant cell lines and four cell lines that exhibit transcriptional silencing of the E-cadherin gene showed Tcf-mediated transcriptional activation. E-cadherin wild-type cell line DU4475 exhibited constitutive Tcf-beta-catenin signaling activity and was found to express truncated APC proteins. These results indicate that if cellular transformation occurred through mutation of E-cadherin, it is not mediated via constitutive activation of the Wnt signaling pathway.
Assuntos
Neoplasias da Mama/genética , Caderinas/genética , Proteínas Proto-Oncogênicas/fisiologia , Transdução de Sinais/fisiologia , Proteínas de Peixe-Zebra , Neoplasias da Mama/metabolismo , Caderinas/biossíntese , Análise Mutacional de DNA , Proteínas de Ligação a DNA/genética , Expressão Gênica , Inativação Gênica , Genes Reporter , Humanos , Luciferases/genética , Fator 1 de Ligação ao Facilitador Linfoide , Mutação , Fatores de Transcrição/genética , Ativação Transcricional/fisiologia , Células Tumorais Cultivadas , Proteínas WntRESUMO
Wingless/Wnt signaling directs cell-fate choices during embryonic development. In Drosophila, Wingless signaling mediates endoderm induction and the establishment of segment polarity in the developing embryo. The fly Wingless cascade is strikingly similar to the vertebrate Wnt signaling pathway, which controls a number of key developmental decisions such as dorsal-ventral patterning in Xenopus. Factors of the TCF/LEF HMG domain family (Tcfs) have recently been established as the downstream effectors of the Wingless/Wnt signal transduction pathways. Upon Wingless/Wnt signaling, a cascade is initiated that results in the accumulation of cytoplasmic beta-catenin (or its fly homolog, Armadillo). There is also a concomitant translocation of beta-catenin/Armadillo to the nucleus, where it interacts with a specific sequence motif at the N terminus of Tcfs to generate a transcriptionally active complex. This bipartite transcription factor is targeted to the upstream regulatory regions of Tcf target genes including Siamois and Nodal related gene-3 in Xenopus, engrailed and Ultrabithorax in Drosophila via the sequence-specific HMG box, and mediates their transcriptional activation by virtue of transactivation domains contributed by beta-catenin/Armadillo. In the absence of Wingless/Wnt signals, a key negative regulator of the pathway, GSK3 beta, is activated, which mediates the downregulation of cytoplasmic beta-catenin/Armadillo via the ubiquitin-proteasome pathway. In the absence of nuclear beta-catenin, the Tcfs recruit the corepressor protein Groucho to the target gene enhancers and actively repress their transcription. An additional corepressor protein, CREB-binding protein (CBP), may also be involved in this repression of Tcf target gene activity. Several other proteins, including adenomatous polyposis coli (APC), GSK3 beta, and Axin/Conductin, are instrumental in the regulation of beta-catenin/Armadillo. In APC-deficient colon carcinoma cell lines, beta-catenin accumulates and is constitutively complexed with nuclear Tcf-4. A proportion of APC wild-type colon carcinomas and melanomas also contains constitutive nuclear Tcf-4/beta-catenin complexes as a result of dominant mutations in the N terminus of beta-catenin that render it insensitive to downregulation by APC, GSK3 beta, and Axin/Conductin. This results in the unregulated expression of Tcf-4 target genes such as c-myc. Based on the established role for Tcf-4 in maintaining intestinal stem cells it is likely that deregulation of c-myc expression as a result of constitutive Tcf-4/beta-catenin activity promotes uncontrolled intestinal cell proliferation. This would readily explain the formation of intestinal polyps during colon carcinogenesis. Similar mechanisms leading to deregulation of Tcf target gene activity are likely to be involved in melanoma and other forms of cancer.
Assuntos
Caderinas/fisiologia , Proteínas do Citoesqueleto/fisiologia , Proteínas de Grupo de Alta Mobilidade/metabolismo , Proteínas Proto-Oncogênicas/fisiologia , Transdução de Sinais , Transativadores , Fatores de Transcrição/metabolismo , Proteínas de Peixe-Zebra , Animais , Padronização Corporal , Neoplasias do Colo/genética , Neoplasias do Colo/fisiopatologia , Drosophila/embriologia , Humanos , Mitógenos/fisiologia , Células Tumorais Cultivadas , Proteínas Wnt , Xenopus/embriologia , Proteínas de Xenopus , beta CateninaRESUMO
The peroxisome proliferator-activated receptor gamma (PPAR gamma), a member of the nuclear receptor superfamily, is expressed at highest levels in adipose tissue and functions as a central regulator in the process of adipocyte differentiation. In the present study, we showed that human leukemic cell lines, not only myeloid but also lymphoid, express PPAR gamma and its activation by natural ligand (15-deoxy-Delta(12,14) - prostaglandin J(2)) and synthetic ligand (troglitazone) profoundly inhibited their proliferation by induction of apoptosis preferentially in the serum-free culture. We pursued its mechanism using the representative cell lines, and found that induction of apoptosis was accompanied by caspase-3 activation and specifically blocked by its inhibitor. While status of several apoptosis-related molecules remained unchanged, the c-Myc expression was markedly down-regulated within 24 h after troglitazone treatment. The c-myc mRNA levels were dramatically reduced at 1 h and became undetectable at 12 h after troglitazone treatment, which proved to be accompanied by complete blockade of the Tcf-4 activity in the electrophoretic mobility shift assay. We succeeded in establishing HL-60 cell lines growing well in the presence of troglitazone in the long-term serum-free culture. They showed neither induction of apoptosis nor down-regulation of the c-Myc expression via blockade of the Tcf-4 activity after troglitazone treatment. This is the first identification of the linkage between PPAR gamma-mediated apoptosis and down-regulation of the c-myc gene expression.
Assuntos
Apoptose/fisiologia , Caspases/metabolismo , Proteínas Proto-Oncogênicas c-myc/biossíntese , Receptores Citoplasmáticos e Nucleares/metabolismo , Tiazolidinedionas , Fatores de Transcrição/metabolismo , Antineoplásicos/farmacologia , Caspase 3 , Cromanos/farmacologia , Proteínas de Ligação a DNA/metabolismo , Regulação para Baixo , Resistencia a Medicamentos Antineoplásicos/fisiologia , Ativação Enzimática/efeitos dos fármacos , Expressão Gênica/fisiologia , Células HL-60 , Humanos , NF-kappa B/metabolismo , Inibidores da Síntese de Ácido Nucleico/farmacologia , Proteínas Proto-Oncogênicas c-myc/genética , RNA Mensageiro/biossíntese , Receptores Citoplasmáticos e Nucleares/fisiologia , Fatores de Transcrição TCF , Tiazóis/farmacologia , Proteína 2 Semelhante ao Fator 7 de Transcrição , Fatores de Transcrição/fisiologia , Troglitazona , Células Tumorais CultivadasRESUMO
Skin permeability to drugs was assessed in the newborn infant using an in vitro method. Excised skin samples were studied in a Franz-type cell, and permeability to 0.1 M sodium salicylate was measured. Fourteen samples were studied, from infants of 25-41 weeks gestation and up to 8 days old. Gestation markedly affected skin permeability to salicylate, absorption being 10(2)-10(3) times greater in infants of 30 weeks gestation or less than in term infants. There are important implications for the high permeability of the preterm infant's skin; accidental poisoning from absorption of topically applied agents can easily occur, and the percutaneous route offers an alternative method of therapeutic drug administration.
Assuntos
Pele/metabolismo , Permeabilidade da Membrana Celular , Idade Gestacional , Humanos , Recém-Nascido , Salicilato de Sódio/metabolismoRESUMO
PURPOSE: To assess risk factors for hepatitis A infection among homosexual and bisexual men during a community-wide outbreak of hepatitis A in New York City. PATIENTS AND METHODS: Twenty-five homosexual and bisexual men, 20 to 49 years of age with hepatitis A identified from health department surveillance data (cases) were compared with 42 homosexual and bisexual men of similar age distribution who were seronegative for hepatitis A virus and identified from private physician offices (controls). Odds ratio (OR) were determined for acute hepatitis A infection according to demographics, numbers of sexual partners, frequency of specific sexual behaviors, and self-reported human immunodeficiency virus status. RESULTS: Cases had more anonymous sex partners (0 to 1 partner versus > 1 partner) than controls during the 6 weeks before illness onset (OR = 4.4, 95% confidence interval [CI] 1.4 to 14.4). Cases were more likely than controls to have engaged in group sex (OR = 3.8, 95% CI 1.1 to 12.6). Among specific sexual behaviors examined, oral-anal intercourse (oral role) and digital-rectal intercourse (digital role) with anonymous sex partners were more commonly reported by cases than controls (OR = 9.7, 95% CI 1.2 to 78.7 and OR = 2.6, 95% CI 1.0 to 7.4, respectively). Multivariate analysis showed that > 1 anonymous sex partner, group sex, oral-anal intercourse, and digital-rectal intercourse were associated with illness in models controlling for duration of sexual activity. Because these variables were highly correlated, independent risk could not be evaluated in a single model. CONCLUSIONS: Hepatitis A infection among homosexual and bisexual men is associated with oral-anal and digital-rectal intercourse, as well as with increasing numbers of anonymous sex partners and group sex. These findings reinforce the importance of developing educational activities for homosexual and bisexual men that focus on risk reduction for hepatitis A as well as other sexually transmitted disease spread via the fecal-oral route.
Assuntos
Bissexualidade , Surtos de Doenças/estatística & dados numéricos , Hepatite A/epidemiologia , Homossexualidade Masculina , Comportamento Sexual , Adulto , Bissexualidade/estatística & dados numéricos , Estudos de Casos e Controles , Hepatite A/etiologia , Homossexualidade Masculina/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Cidade de Nova Iorque/epidemiologia , Fatores de Risco , Comportamento Sexual/estatística & dados numéricos , Inquéritos e QuestionáriosRESUMO
The publication of black and white photomicrographs has a long tradition in pathology. High-resolution film and quality objectives have been the backbone of generating quality photomicrographs suitable for publication. However, the digital imaging revolution has changed the way we view and capture images. As the quality of image capture devices increases and as their price decreases, more and more investigators are using digital imaging, and the use of color digital imaging for teleconferencing, telediagnosis, and reproduction is now well established. The purpose of this study was to determine the file sizes needed to obtain publication-quality black and white images using digital imaging technology. In this study, four experts in renal pathology reviewed 70 black and white images of various file sizes obtained from specimens representing a variety of renal histopathology. Without knowledge of the file size, the four renal pathologists graded the degree of pixelation, and the overall diagnostic and publication quality of the images. In all cases, digital imaging was capable of obtaining publication quality images equal to those achieved using film. The file size needed to achieve publication quality black and white images depended on magnification, with lower magnification images requiring larger file sizes.
Assuntos
Diagnóstico por Imagem/métodos , Processamento de Imagem Assistida por Computador/métodos , Fotomicrografia/métodos , Redes de Comunicação de Computadores , Humanos , Nefropatias/patologia , Variações Dependentes do Observador , EditoraçãoRESUMO
From January to April, 1990, 695 measles cases were reported to the Puerto Rico Health Department; there were 12 measles-associated deaths (case fatality ratio, 17/1000), more than in any year since 1967. We conducted a case-control study of risk factors for severe measles. We identified 16 children (ages 5 to 34 months) with severe measles and selected children with nonsevere measles as controls (39 hospitalized and 38 nonhospitalized). Controls were frequency matched to severe measles cases by region of residence. One case and two controls had been vaccinated. An underlying illness was present in 50% of cases and 16% of nonhospitalized controls (Mantel-Haenszel weighted odds ratio 5.3; 95% confidence interval 1.4, 20.2). In a multivariate analysis cases were significantly more likely than hospitalized controls to be from families with an annual income of < $5000 (odds ratio (OR), 26.9), to have a mother without a high school degree (OR 11.1), to be anemic (hemoglobin < 10 g/dl) (OR 15.9) and have an underlying illness (OR 18.3). During measles outbreaks preventing severe illness requires aggressive control measures and strategies to increase vaccine coverage of children with underlying illnesses and of low socioeconomic status.