RESUMO
BACKGROUND: Prenatal alcohol exposure (PAE) affects embryonic development, causing a variable fetal alcohol spectrum disorder (FASD) phenotype with neuronal disorders and birth defects. We hypothesize that early alcohol-induced epigenetic changes disrupt the accurate developmental programming of embryo and consequently cause the complex phenotype of developmental disorders. To explore the etiology of FASD, we collected unique biological samples of 80 severely alcohol-exposed and 100 control newborns at birth. METHODS: We performed genome-wide DNA methylation (DNAm) and gene expression analyses of placentas by using microarrays (EPIC, Illumina) and mRNA sequencing, respectively. To test the manifestation of observed PAE-associated DNAm changes in embryonic tissues as well as potential biomarkers for PAE, we examined if the changes can be detected also in white blood cells or buccal epithelial cells of the same newborns by EpiTYPER. To explore the early effects of alcohol on extraembryonic placental tissue, we selected 27 newborns whose mothers had consumed alcohol up to gestational week 7 at maximum to the separate analyses. Furthermore, to explore the effects of early alcohol exposure on embryonic cells, human embryonic stem cells (hESCs) as well as hESCs during differentiation into endodermal, mesodermal, and ectodermal cells were exposed to alcohol in vitro. RESULTS: DPPA4, FOXP2, and TACR3 with significantly decreased DNAm were discovered-particularly the regulatory region of DPPA4 in the early alcohol-exposed placentas. When hESCs were exposed to alcohol in vitro, significantly altered regulation of DPPA2, a closely linked heterodimer of DPPA4, was observed. While the regulatory region of DPPA4 was unmethylated in both control and alcohol-exposed hESCs, alcohol-induced decreased DNAm similar to placenta was seen in in vitro differentiated mesodermal and ectodermal cells. Furthermore, common genes with alcohol-associated DNAm changes in placenta and hESCs were linked exclusively to the neurodevelopmental pathways in the enrichment analysis, which emphasizes the value of placental tissue when analyzing the effects of prenatal environment on human development. CONCLUSIONS: Our study shows the effects of early alcohol exposure on human embryonic and extraembryonic cells, introduces candidate genes for alcohol-induced developmental disorders, and reveals potential biomarkers for prenatal alcohol exposure.
Assuntos
Transtornos do Espectro Alcoólico Fetal , Proteínas Nucleares , Efeitos Tardios da Exposição Pré-Natal , Feminino , Humanos , Recém-Nascido , Gravidez , Biomarcadores/metabolismo , Cromatina , Deficiências do Desenvolvimento , Etanol/toxicidade , Transtornos do Espectro Alcoólico Fetal/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Placenta/metabolismoRESUMO
BACKGROUND: Specific medical guidelines for health surveillance exist for people with Down syndrome (DS) since 25 years but knowledge of adherence to the guidelines is lacking. The guidelines were developed to avoid unnecessary suffering from preventable conditions. The aims of the study were to investigate 1) planned health care visits in relation to the co-morbidities described in specific medical guidelines as a measure of adherence, 2) unplanned health care visits as a measure of potentially unmet health care needs and 3) gender differences in health care utilisation among older people with DS. METHODS: This register-based study includes people with DS (n = 472) from a Swedish national cohort of people with intellectual disability (n = 7936), aged 55 years or more, and with at least one support according to the disability law, in 2012. Data on inpatient and outpatient specialist health care utilisation were collected from the National Patient Register for 2002-2012. RESULTS: A total of 3854 inpatient and outpatient specialist health care visits were recorded during the 11 years, of which 54.6% (n = 2103) were planned, 44.0% (n = 1695) unplanned and 1.4% (n = 56) lacked information. More than half of the visits, 67.0% (n = 2582) were outpatient health care thus inpatient 33% (n = 1272). Most planned visits (29.4%, n = 618) were to an ophthalmology clinic, and most unplanned visits to an internal medicine clinic (36.6%, n = 621). The most common cause for planned visits was cataract, found at least once for 32.8% in this cohort, followed by arthrosis (8.9%), epilepsy (8.9%) and dementia (6.6%). Pneumonia, pain, fractures and epilepsy each accounted for at least one unplanned visit for approximately one-fourth of the population (27.1, 26.9, 26.3 and 19.7% respectively). Men and women had similar numbers of unplanned visits. However, women were more likely to have visits for epilepsy or fractures, and men more likely for pneumonia. CONCLUSIONS: Increased awareness of existing specific medical guidelines for people with DS is vital for preventive measures. The relatively few planned health care visits according to the medical guidelines together with a high number of unplanned visits caused by conditions which potentially can be prevented suggest a need of improved adherence to medical guidelines.
Assuntos
Síndrome de Down/terapia , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Idoso , Estudos de Coortes , Síndrome de Down/epidemiologia , Feminino , Fidelidade a Diretrizes/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Sistema de Registros , Suécia/epidemiologiaRESUMO
AIM: To identify combined positron-emission tomography (PET)/magnetic resonance imaging (MRI)-based radiomics as a surrogate biomarker of intratumour disease risk for molecular subtype ccA and ccB in patients with primary clear cell renal cell carcinoma (ccRCC). MATERIALS AND METHODS: PET/MRI data were analysed retrospectively from eight patients. One hundred and sixty-eight radiomics features for each tumour sampling based on the regionally sampled tumours with 23 specimens were extracted. Sparse partial least squares discriminant analysis (SPLS-DA) was applied to feature screening on high-throughput radiomics features and project the selected features to low-dimensional intrinsic latent components as radiomics signatures. In addition, multilevel omics datasets were leveraged to explore the complementing information and elevate the discriminative ability. RESULTS: The correct classification rate (CCR) for molecular subtype classification by SPLS-DA using only radiomics features was 86.96% with permutation test p=7×10-4. When multi-omics datasets including mRNA, microvascular density, and clinical parameters from each specimen were combined with radiomics features to refine the model of SPLS-DA, the best CCR was 95.65% with permutation test, p<10-4; however, even in the case of generating the classification based on transcription features, which is the reference standard, there is roughly 10% classification ambiguity. Thus, this classification level (86.96-95.65%) of the proposed method represents the discriminating level that is consistent with reality. CONCLUSION: Featured with high accuracy, an integrated multi-omics model of PET/MRI-based radiomics could be the first non-invasive investigation for disease risk stratification and guidance of treatment in patients with primary ccRCC.
Assuntos
Carcinoma de Células Renais/diagnóstico por imagem , Carcinoma de Células Renais/patologia , Neoplasias Renais/diagnóstico por imagem , Neoplasias Renais/patologia , Imagem Multimodal , Biomarcadores Tumorais , Meios de Contraste , Humanos , Imageamento Tridimensional , Imageamento por Ressonância Magnética , Gradação de Tumores , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons , Estudos RetrospectivosRESUMO
BACKGROUND: Obesity and lack of physical activity are frequently reported in persons with intellectual disability (ID) or autism spectrum disorder (ASD). We hypothesised a higher prevalence of diabetes and hypertension in this population. METHOD: We used administrative data for all primary and specialist outpatient and inpatient healthcare consultations for people with at least one recorded diagnosis of diabetes mellitus, hypertension or obesity from 1998 to 2015. Data were drawn from the central administrative database for Stockholm County, Sweden. It was not possible to separate data for type 1 and type 2 diabetes. We stratified 26 988 individuals with IDs or ASD into three groups, with Down syndrome treated separately, and compared these groups with 1 996 140 people from the general population. RESULTS: Compared with the general population, men and women with ID/ASD had 1.6-3.4-fold higher age-adjusted odds of having a registered diagnosis of obesity or diabetes mellitus, with the exception of diabetes among men with Down syndrome. A registered diagnosis of hypertension was only more common among men with ID/ASD than in the general population. CONCLUSIONS: Diabetes and blood pressure health screening, along with efforts to prevent development of obesity already in childhood, are necessary for individuals with IDs and ASD. We believe that there is a need for adapted community-based health promotion programmes to ensure more equitable health for these populations.
Assuntos
Transtorno do Espectro Autista/epidemiologia , Diabetes Mellitus/epidemiologia , Hipertensão/epidemiologia , Deficiência Intelectual/epidemiologia , Obesidade/epidemiologia , Adolescente , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Comorbidade , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Distribuição por Sexo , Suécia/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Computer based methods are increasingly being used for training workers, although our understanding of how to structure this training has not kept pace with the changing abilities of computers. Information on a computer can be presented in many different ways and the style of presentation can greatly affect learning outcomes and the effectiveness of the learning intervention. Many questions about how adults learn from different types of presentations and which methods best support learning remain unanswered. AIMS: To determine if computer based methods, which have been shown to be effective on younger students, can also be an effective method for older workers in occupational health and safety training. METHODS: Three versions of a computer based respirator training module were developed and presented to manufacturing workers: one consisting of text only; one with text, pictures, and animation; and one with narration, pictures, and animation. After instruction, participants were given two tests: a multiple choice test measuring low level, rote learning; and a transfer test measuring higher level learning. RESULTS: Participants receiving the concurrent narration with pictures and animation scored significantly higher on the transfer test than did workers receiving the other two types of instruction. There were no significant differences between groups on the multiple choice test. CONCLUSIONS: Narration with pictures and text may be a more effective method for training workers about respirator safety than other popular methods of computer based training. Further study is needed to determine the conditions for the effective use of this technology.
Assuntos
Instrução por Computador/métodos , Saúde Ocupacional , Adulto , Recursos Audiovisuais , Avaliação Educacional , Tecnologia Educacional , Feminino , Humanos , Aprendizagem , Masculino , Microcomputadores , Pessoa de Meia-Idade , Segurança , Ventiladores MecânicosRESUMO
Beginning dental students normally receive their first exposure to the study of tooth forms (morphology) through a dental anatomy laboratory course in which they are required to reproduce tooth morphology, usually with wax. The fabrication of a tooth in wax requires proper visual recognition skills and fine eye-hand coordination. Many students struggle with one or both of these. A computer program, designed to teach recognition concepts, was delivered to three groups of beginning freshman dental students in conjunction with their dental anatomy laboratory course while a group of their classmates served as the controls. This study investigated (1) instructional design and interface improvement and (2) the best method to implement the computer program. Experimental and control groups all received normal daily critiques of their course project work. After completion of the computer program, all groups were tested with a recognition-based examination as well as with a practical examination, requiring the reproduction of a tooth in wax. All experimental groups scored better than the control group on both examinations. Results indicated that computer-based instruction may be a useful means to foster visual concept development. An expanded program, using better graphics, animation and movies is currently under development.
Assuntos
Anatomia/educação , Instrução por Computador , Educação em Odontologia , Software , Dente/anatomia & histologia , Recursos Audiovisuais , Gráficos por Computador , Estudos de Avaliação como Assunto , Humanos , Modelos Anatômicos , Materiais de Ensino , Interface Usuário-ComputadorAssuntos
Ritmo Circadiano , Estro , Metiltransferases/metabolismo , Glândula Pineal/enzimologia , Animais , Radioisótopos de Carbono , Colo do Útero/fisiologia , Copulação , Escuridão , Feminino , Indóis , Matemática , Melatonina/biossíntese , Modelos Biológicos , Ovário/fisiologia , Gravidez , Ratos , Fatores de Tempo , Vagina/fisiologiaAssuntos
Carcinoma de Células Renais/imunologia , Citotoxicidade Imunológica , Proteínas de Choque Térmico/fisiologia , Interleucina-2/imunologia , Neoplasias Renais/imunologia , Células Matadoras Naturais/imunologia , Membrana Celular/imunologia , Membrana Celular/fisiologia , Regulação Neoplásica da Expressão Gênica , Proteínas de Choque Térmico HSP72 , Proteínas de Choque Térmico/genética , Antígenos de Histocompatibilidade Classe I/análise , Antígenos de Histocompatibilidade Classe I/genética , Temperatura Alta , Humanos , Hipertermia Induzida , Interleucina-2/farmacologia , Masculino , Neoplasias da Próstata , Fatores de Tempo , Células Tumorais CultivadasRESUMO
Inappropriate kinase expression and subsequent promiscuous activity defines the transformation of many solid tumors including renal cell carcinoma (RCC). Thus, the expression of novel tumor-associated kinases has the potential to dramatically shape tumor cell behavior. Further, identifying tumor-associated kinases can lend insight into patterns of tumor growth and characteristics. Here, we report the identification of the RTK-like orphan receptor 2 (Ror2), a new tumor-associated kinase in RCC cell lines and primary tumors. Ror2 is an orphan receptor tyrosine kinase with physiological expression normally seen in the embryonic kidney. However, in RCC, Ror2 expression correlated with expression of genes involved at the extracellular matrix, including Twist and matrix metalloprotease-2 (MMP2). Expression of MMP2 in RCC cells was suppressed by Ror2 knockdown, placing Ror2 as a mediator of MMP2 regulation in RCC and a potential regulator of extracellular matrix remodeling. The suppression of Ror2 not only inhibited cell migration, but also inhibited anchorage-independent growth in soft agar and growth in an orthotopic xenograft model. These findings suggest a novel pathway of tumor-promoting activity by Ror2 within a subset of renal carcinomas, with significant implications for unraveling the tumorigenesis of RCC.
Assuntos
Carcinoma de Células Renais/patologia , Proliferação de Células , Neoplasias Renais/patologia , Receptores de Superfície Celular/metabolismo , Animais , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Immunoblotting , Imuno-Histoquímica , Neoplasias Renais/genética , Neoplasias Renais/metabolismo , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 2 da Matriz/metabolismo , Camundongos , Camundongos Nus , Transplante de Neoplasias , Neoplasias Experimentais/genética , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Fosforilação , Interferência de RNA , Receptores Proteína Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases/metabolismo , Receptores Órfãos Semelhantes a Receptor Tirosina Quinase , Receptores de Superfície Celular/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transplante Heterólogo , Carga Tumoral , Proteína 1 Relacionada a Twist/genética , Proteína 1 Relacionada a Twist/metabolismoRESUMO
A review of the literature suggests that surgical treatment of transchondral talar dome fractures affords superior results over lengthy conservative therapy. Medial lesions have been reported most often. The authors perform stress views in acute and chronic ankle injuries, as there are often associated ligament ruptures with suspected talar dome fractures, and routinely use an air-contrast radiographic technique for visualization of the continuity of the articular cartilage. An arthrogram is performed for definitive diagnosis of ligamentous injury. A new osseous surgical approach to the medial talar dome has been presented, entailing a crescentic osteotomy of the medial malleolus. The distinct advantage has proven to be enhanced exposure to the middle and posterior aspects of the medial margin of the talus. The configuration of the crescentic osteotomy is also amenable to internal fixation and tension band wiring has been recommended. Unrestricted access to the site of a medial transchondral talar dome fracture through this osteotomy is the benefit of a technically well-performed procedure.
Assuntos
Osteocondrite Dissecante/cirurgia , Osteocondrite/cirurgia , Osteotomia/métodos , Tálus , Artrografia , Parafusos Ósseos , Fios Ortopédicos , Fixação Interna de Fraturas , Humanos , Osteocondrite Dissecante/classificação , Osteocondrite Dissecante/diagnóstico por imagem , Tomografia por Raios XRESUMO
Animals inhabiting areas where there are drastic changes in the environment often reproduce only during limited time periods to ensure that young are raised in optimal environmental conditions. The lack of a well defined breeding season in many domesticated animals, presumably because the selective pressures for seasonal breeding have been minimized, suggests that the neuroendocrine events controlling seasonal cyclicity have been bred out of these animals. Little is known about the underlying neuroendocrine changes which may occur during the evolution of a species from a seasonal to a nonseasonal breeder. Whereas the changing photoperiod is the primary environmental cue which initiates and/or terminates the reproductive season in many animals, this is not so in the albino rat Rattus norvegicus, a model nonseasonal breeder. Nevertheless, daylength can influence various reproductive parameters in laboratory rats, suggesting that some of the neuroendocrine components that controlled seasonal breeding previously are still extant in this species. To test this hypothesis, we investigated the effect of daylength on the responsiveness of the neuroendocrine--gonadal axis to the negative-feedback effects of testosterone. This paradigm was chosen because of the important role played by photic-induced changes in steroid feedback sensitivity in the control of seasonal reproduction. We report here that although daylength has very little effect on neuroendocrine--gonadal function in the intact male laboratory rat, it seems that some component(s) of a photoperiodic system involving the pineal gland has been preserved.
Assuntos
Animais de Laboratório/fisiologia , Luz , Periodicidade , Animais , Hormônio Foliculoestimulante/sangue , Hormônio Luteinizante/sangue , Masculino , Tamanho do Órgão , Glândula Pineal/fisiologia , Ratos , Reprodução , Testículo/anatomia & histologia , Testosterona/farmacologiaRESUMO
Previous studies indicate that steroid hormones alter pineal biochemistry, and it has been suggested that at least part of the negative feedback effect of steroid hormones on pituitary gonadotropin release may be mediated by the pineal gland. In this study, pinealectomy did not alter the inhibitory effect of testosterone on neuroendocine-gonadal activity in the male rat, suggesting that the pineal gland does not mediate the response of the rat hypothalamic-pituitary axis to testosterone.
Assuntos
Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Glândula Pineal/fisiologia , Testículo/efeitos dos fármacos , Testosterona/farmacologia , Animais , Castração , Hormônio Foliculoestimulante/sangue , Hormônio Luteinizante/sangue , Masculino , Tamanho do Órgão/efeitos dos fármacos , RatosRESUMO
PURPOSE: The objective of this study was to investigate growth-inhibitory and apoptotic activity of the experimental antitumor drug, brefeldin A (BFA), on primary cultures of human epithelial cells derived from prostatic adenocarcinomas. MATERIALS AND METHODS: Clonal assays were performed to evaluate the effects of BFA on growth of prostatic cancer cell strains. Loss of cell viability in response to BFA was assessed by trypan blue exclusion. Induction of apoptosis by BFA was evaluated by morphologic criteria, electrophoretic assay of DNA fragmentation, and a cell death ELISA. Immunoblots were used to monitor p53 and pRB expression in response to BFA. RESULTS: BFA was growth-inhibitory at a half-maximal concentration of 5 ng./ml. (18 nM). Morphological manifestations of apoptosis were evident by 24 hours of treatment. Cell viability declined and the cell death ELISA indicated an 18-fold increase in apoptosis in BFA-treated versus untreated cells at 48 hours. DNA fragmentation was also seen at 48 hours. Levels of p53 were not altered by BFA, but pRB was maintained in a hypophosphorylated state by BFA treatment. CONCLUSIONS: BFA is a potent inducer of apoptosis in prostatic cancer cells via a p53-independent mechanism. Cells derived from low-grade as well as high-grade cancers responded similarly to BFA. Since p53-mediated pathways of apoptosis may frequently be abrogated in prostatic cancer cells, agents such as BFA that induce p53-independent cell death may be promising candidates for chemotherapeutic agents.
Assuntos
Adenocarcinoma/tratamento farmacológico , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Brefeldina A/uso terapêutico , Genes p53/genética , Neoplasias da Próstata/tratamento farmacológico , Inibidores da Síntese de Proteínas/uso terapêutico , Adenocarcinoma/genética , Adenocarcinoma/patologia , Apoptose/genética , Morte Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Clonais/efeitos dos fármacos , Corantes , Fragmentação do DNA , Eletroforese em Gel de Ágar , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Células Epiteliais/efeitos dos fármacos , Humanos , Immunoblotting , Masculino , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Proteína do Retinoblastoma/efeitos dos fármacos , Azul Tripano , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/efeitos dos fármacosRESUMO
OBJECTIVE: Systematic sextant biopsies are a powerful tool in the diagnosis of prostate cancer. Interpretation of the histopathologic results of these biopsies plays a central role in treatment decisions. This biopsy approach was originally described as sampling the prostate in the mid-lobe, parasagittal plane at the apex, mid-gland, and base, bilaterally. Morphometric analysis of prostate specimens has revealed that most clinically significant cancers are mainly located in the posterolateral aspect of the gland, not the mid-lobe. We sought to determine if cancer detection could be improved by obtaining more laterally placed biopsies. MATERIALS AND METHODS: Forty-one patients underwent transrectal ultrasound with mid-lobe sextant as well as lateral sextant biopsies. Biopsy specimens were evaluated for Gleason grade and length of cancer present in each core. The mid-lobe and lateral biopsy results were then compared. RESULTS: Thirteen of 41 patients (31.7%) were found to have no cancer on either biopsy set. Cancer was detected by both the mid-lobe and the lateral biopsies in 19 patients (46.3%). In 6 patients (14.6%), only the lateral biopsies revealed cancer, and in 3 patients (7.3%), only the mid-lobe biopsies revealed cancer. CONCLUSIONS: Laterally-placed systematic sextant biopsies may yield an improved diagnosis rate in patients with palpable nodularity in the lateral aspect of the prostate, patients without any palpable abnormalities but with elevated PSA levels, and in those patients undergoing repeat biopsies.
Assuntos
Biópsia por Agulha/métodos , Próstata/patologia , Neoplasias da Próstata/diagnóstico , Adenocarcinoma/diagnóstico , Adenocarcinoma/patologia , Humanos , Masculino , Palpação , Neoplasias da Próstata/patologiaRESUMO
Cells, animals, and humans respond to hyperthermia through the synthesis of a family of proteins termed heat shock proteins (HSPs). Because hyperthermic stress may also result in mitochondrial uncoupling and the generation of reactive oxygen species, we wondered whether oxidant stress was sufficient to increase cellular levels of HSP70. HSP70 was detected in cells heated or treated with menadione but not in those treated with hydrogen peroxide or xanthine/xanthine oxidase. We speculate that oxidant stress from menadione exposure is qualitatively different from exposure from hydrogen peroxide or xanthine/xanthine oxidase.
Assuntos
Proteínas de Choque Térmico/biossíntese , Hipertermia Induzida , Oxidantes/farmacologia , Estresse Oxidativo , Animais , Humanos , Células Tumorais Cultivadas , Vitamina K/farmacologiaRESUMO
Cells respond to a variety of stresses by synthesizing a family of proteins termed heat-shock proteins (HSP). Recently, the 3'-untranslated regions (UTRs) of some mRNAs have been shown to be important in the posttranscriptional regulation of protein production. Therefore, we hypothesized that heat could regulate HSP70 production through the HSP70 3'-UTR, in addition to its known effects on transcription. To test this hypothesis, cells were transfected with either a plasmid containing sequences encoding the human HSP70 or beta-globin 3'-untranslated region placed downstream of a chloramphenicol acetyltransferase (CAT) reporter gene. In both plasmids, the CAT gene was driven by an SV40 promoter. Following heat stress, cells transfected with the CAT construct containing the HSP70 3'-UTR showed increased CAT activity relative to the beta-globin 3'-UTR construct. This effect paralleled increases in HSP70 mRNA and levels of the inducible HSP70 protein by Western blot. These studies identify a heat-induced mechanism of posttranscriptional control of HSP70 synthesis utilizing the HSP70 3'-UTR, which may be important in the cells ability to regulate the heat-shock response.
Assuntos
Proteínas de Choque Térmico/genética , Temperatura Alta , Estresse Fisiológico/genética , Sequência de Bases , Linhagem Celular Transformada , Cloranfenicol O-Acetiltransferase/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Sondas Moleculares/genética , Dados de Sequência Molecular , Biossíntese de Proteínas , RNA Mensageiro/metabolismoRESUMO
The mechanisms by which heat injury results in multiorgan system failure are unknown, but the presence of endotoxemia and intestinal hemorrhage suggests that changes in gut epithelial permeability may be crucial to this process. To determine whether alterations in epithelial permeability occur at physiologically relevant temperatures, heat-induced changes on epithelial barrier integrity were studied using a high-resistance clone of Madin-Darby canine kidney epithelial cells. Transepithelial electrical conductance increased when monolayers were heated above 38.3 degrees C. Early changes in conductance were completely reversible with cooling. Increased conductance was due to increased paracellular permeability because heat also induced increased mannitol permeability across the monolayers. A conditioning heat stress (42 degrees C for 90 min) altered heat-induced permeability. When cell monolayers were exposed to this conditioning stress 48 h before measurement of conductance with increasing temperatures, the conductance increase did not occur until they were heated to 39.4 degrees C compared with 38.8 degrees C in naive control cells. This conditioning treatment also conferred thermotolerance as measured by cell survival after a lethal 45.0 degrees C heat stress. There was no difference in the temperature at which conductance increased between preheated and control cells 96 h after a preconditioning heat stress. The conditioning heat stress resulted in accumulation of heat-shock protein (HSP) 70 in cells at 48 h, but HSP 70 returned to control levels at 96 h. These studies demonstrate that small temperature elevations increase epithelial permeability and that prior heat stress which induces HSP 70 shifts the threshold temperature required to disrupt the epithelium.