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1.
Med Vet Entomol ; 28 Suppl 1: 60-7, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24898348

RESUMEN

Dirofilaria immitis Leidy (Spirurida: Onchocercidae), or heartworm, is a mosquito-borne nematode that causes a fatal disease in carnivores. Although infection is preventable through prophylactic drugs, compliance and the spectre of resistance suggest vector control is a viable alternative. There were two main objectives in this study: (a) to evaluate the relationships between landscape and social factors and the number and species of heartworm-positive mosquitoes, with a specific focus on the importance of the invasive Asian tiger mosquito, Aedes albopictus (Skuse) (Stegomyia albopicta) (Diptera: Culicidae), and (b) to test the hypothesis that dog heartworm is more prevalent in suburban than in rural areas. To achieve these objectives, mosquitoes were collected from May to November 2010 at 16 rural and 16 urban locations in Payne County, Oklahoma, U.S.A. using three trapping methods that utilized, respectively, resting boxes, carbon dioxide traps and BG Sentinel traps. Urban areas showed greater numbers of Ae. albopictus and a higher overall likelihood of infection with D. immitis. Because many species of mosquito are responsible for heartworm transmission, current prophylactic treatment remains the best method of controlling this parasite.


Asunto(s)
Culicidae/parasitología , Dirofilaria immitis/fisiología , Dirofilariasis/transmisión , Enfermedades de los Perros/transmisión , Insectos Vectores/parasitología , Aedes/parasitología , Animales , Dirofilariasis/parasitología , Enfermedades de los Perros/parasitología , Perros , Ambiente , Oklahoma , Estaciones del Año , Factores Socioeconómicos , Especificidad de la Especie
2.
mBio ; 14(1): e0311622, 2023 02 28.
Artículo en Inglés | MEDLINE | ID: mdl-36598261

RESUMEN

Chronic gastric infection with Helicobacter pylori can lead to progressive tissue changes that culminate in cancer, but how H. pylori adapts to the changing tissue environment during disease development is not fully understood. In a transgenic mouse gastric metaplasia model, we found that strains from unrelated individuals differed in their ability to infect the stomach, to colonize metaplastic glands, and to alter the expression of the metaplasia-associated protein TFF3. H. pylori isolates from different stages of disease from a single individual had differential ability to colonize healthy and metaplastic gastric glands. Exposure to the metaplastic environment selected for high gastric colonization by one of these strains. Complete genome sequencing revealed a unique alteration in the frequency of a variant allele of the putative adhesin sabB, arising from a recombination event with the related sialic acid binding adhesin (SabA) gene. Mutation of sabB in multiple H. pylori strain backgrounds strongly reduced adherence to both normal and metaplastic gastric tissue, and highly attenuated stomach colonization in mice. Thus, the changing gastric environment during disease development promotes bacterial adhesin gene variation associated with enhanced gastric colonization. IMPORTANCE Chronic infection with Helicobacter pylori is the primary risk factor for developing stomach cancer. As disease progresses H. pylori must adapt to a changing host tissue environment that includes induction of new cell fates in the cells that line the stomach. We tested representative H. pylori isolates collected from the same patient during early and later stages of disease in a mouse model where we can rapidly induce disease-associated tissue changes. Only the later-stage H. pylori strains could robustly colonize the diseased stomach environment. We also found that the ability to colonize the diseased stomach was associated with genetic variation in a putative cell surface adhesin gene called sabB. Additional experiments revealed that SabB promotes binding to stomach tissue and is critical for stomach colonization by the late-stage strains. Thus, H. pylori diversifies its genome during disease progression and these genomic changes highlight critical factors for bacterial persistence.


Asunto(s)
Infecciones por Helicobacter , Helicobacter pylori , Neoplasias Gástricas , Ratones , Animales , Helicobacter pylori/genética , Helicobacter pylori/metabolismo , Infección Persistente , Adhesinas Bacterianas/genética , Adhesinas Bacterianas/metabolismo , Infecciones por Helicobacter/microbiología , Mucosa Gástrica/microbiología , Ratones Transgénicos , Neoplasias Gástricas/microbiología , Metaplasia/complicaciones , Metaplasia/metabolismo
3.
AIDS Care ; 22(6): 751-8, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20467942

RESUMEN

With the increasing availability of highly active antiretroviral therapy, vertically infected children have a better chance of surviving into adolescence and adulthood. Additionally, sexual transmission of human immunodeficiency virus (HIV) remains a problem, and incidence and prevalence among youth remain high. Therefore, HIV-infected adolescents are becoming a more prominent sub-group in the HIV/AIDS epidemic. Experience from the developed world indicates that providing effective care and treatment for adolescents poses unique challenges. This study aimed to identify the experiences and needs of adolescents growing up in care or on treatment for HIV in Cape Town, South Africa. Four focus groups interviews were conducted with a total of 26 young people attending an adolescent infectious diseases clinic at a tertiary hospital. Questions explored participant's perceptions on their present and future lives, and their self-identified needs. Focus groups revealed that adolescents viewed their illness negatively, but that social issues such as violence and poverty were also concerns. Despite these stressors, most respondents remained positive about the present and future, and wanted support for achieving their goals. As increasing numbers of HIV-infected children enter adolescence, healthcare providers and communities must find ways to support these young people to transition into adulthood.


Asunto(s)
Terapia Antirretroviral Altamente Activa , Infecciones por VIH/psicología , Problemas Sociales , Adolescente , Servicios de Salud del Adolescente , Actitud Frente a la Salud , Niño , Femenino , Grupos Focales , Infecciones por VIH/tratamiento farmacológico , Humanos , Masculino , Evaluación de Necesidades , Investigación Cualitativa , Sudáfrica , Violencia
4.
Br J Cancer ; 101(3): 410-7, 2009 Aug 04.
Artículo en Inglés | MEDLINE | ID: mdl-19603019

RESUMEN

BACKGROUND: Plasma biomarkers may be particularly useful as a predictor or early marker of clinical response to treatment in addition to radiological imaging. Cytokeratin 18 (CK18) is an epithelial-specific cytokeratin that undergoes cleavage by caspases during apoptosis. Measurement of caspase-cleaved (CK18-Asp396) or total cytokeratin 18 (CK18) from epithelial-derived tumours could be a simple, non-invasive way to monitor or predict responses to treatment. METHODS: Soluble plasma CK18-Asp396 and CK18 were measured by ELISA from 73 patients with advanced gastrointestinal adenocarcinomas before treatment and during chemotherapy, as well as 100 healthy volunteers. RESULTS: Both CK18-Asp396 and total CK18 plasma levels were significantly higher in patients compared with the healthy volunteers (P=0.015, P<0.001). The total CK18 baseline plasma levels before treatment were significantly higher (P=0.009) in patients who develop progressive disease than those who achieve partial response or stable disease and this correlation was confirmed in an independent validation set. The peak plasma levels of CK18 occurring in any cycle following treatment were also found to be associated with tumour response, but peak levels of CK18-Asp396 did not reach significance (P=0.01, and P=0.07, respectively). CONCLUSION: Plasma levels CK18 are a potential marker of tumour response in patients with advanced gastrointestinal malignancy.


Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Biomarcadores de Tumor/sangre , Neoplasias Gastrointestinales/tratamiento farmacológico , Queratina-18/sangre , Adenocarcinoma/sangre , Adulto , Anciano , Anciano de 80 o más Años , Ensayo de Inmunoadsorción Enzimática , Femenino , Neoplasias Gastrointestinales/sangre , Humanos , Masculino , Persona de Mediana Edad
6.
J Infect Prev ; 17(2): 53-62, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28989455

RESUMEN

INTRODUCTION: A variety of methods are in use for decontaminating breast pump milk collection kits and related items associated with infant feeding. This paper aims to provide best practice guidance for decontamination of this equipment at home and in hospital. It has been compiled by a joint Working Group of the Healthcare Infection Society and the Infection Prevention Society. METHODS: The guidance has been informed by a search of the literature in Medline, the British Nursing Index, the Cumulative Index to Nursing & Allied Health Literature, Midwifery & Infant Care and the results of two surveys of UK neonatal units in 2002/3 and 2006, and of members of the Infection Prevention Society in 2014. Since limited good quality evidence was available from these sources much of the guidance represents good practice based on the consensus view of the Working Group. KEY RECOMMENDATIONS: Breast pump milk collection kits should not be reused by different mothers unless they have been sterilized in a Sterile Services Department between these different users.When used by the same mother, a detergent wash followed by thorough rinsing and drying after each use gives acceptable decontamination for most circumstances, as long as it is performed correctly.Additional decontamination precautions to washing, rinsing and drying may be used if indicated by local risk assessments and on advice from the departmental clinicians and Infection Prevention and Control Teams. The microbiological quality of the rinse water is an important consideration, particularly for infants on neonatal units.If bottle brushes or breast/nipple shields are used, they should be for use by one mother only. Decontamination should be by the processes used for breast pump milk collection kits.Dummies (soothers, pacifiers or comforters) needed for non-nutritive sucking by infants on neonatal units, should be for single infant use. Manufacturers should provide these dummies ready-to-use and individually packaged. They must be discarded at least every 24 hours or immediately if soiled with anything other than the baby's saliva. No attempt should be made to decontaminate the dummies, either before or during use. CONCLUSION: This guidance provides practical recommendations to support the safe decontamination of breast pump milk collection kits for healthcare professionals to use and communicate to other groups such as parents and carers.

7.
J Hosp Infect ; 92(3): 213-21, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26679726

RESUMEN

INTRODUCTION: A variety of methods are in use for decontaminating breast pump milk collection kits and related items associated with infant feeding. This paper aims to provide best practice guidance for decontamination of this equipment at home and in hospital. It has been compiled by a Joint Working Group of the Healthcare Infection Society and the Infection Prevention Society. METHODS: The guidance has been informed by a search of the literature in Medline, the British Nursing Index, the Cumulative Index to Nursing and Allied Health Literature, Midwifery and Infant Care, and the results of two surveys of UK neonatal units in 2002/3 and 2006, and of members of the Infection Prevention Society in 2014. Since limited good quality evidence was available from these sources, much of the guidance represents good practice based on the consensus view of the Working Group. CONCLUSION: This guidance provides practical recommendations to support the safe decontamination of breast pump milk collection kits for healthcare professionals to use and communicate to other groups such as parents and carers.


Asunto(s)
Descontaminación/métodos , Desinfección/métodos , Equipos y Suministros/microbiología , Mastitis/prevención & control , Leche Humana , Animales , Composición Familiar , Femenino , Hospitales , Humanos , Reino Unido
8.
Oncogene ; 17(3): 293-301, 1998 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-9690511

RESUMEN

The E8 open reading frame of Bovine papillomavirus type 4 (BPV-4) encodes a small (42 amino acid) hydrophobic polypeptide localized to cellular membranes and capable of conferring an anchorage-independent (AI) growth phenotype on primary bovine cells co-transfected with BPV-4 E7 ORF and an activated ras gene. To further study the function of E8 independently of other viral gene products, we have expressed it in the murine fibroblast cell line, NIH3T3. Cells expressing E8 are capable of AI growth and escape growth arrest after serum withdrawal. E8 deregulates cyclin A expression, induces transactivation of the human cyclin A gene promoter and increases endogenous protein levels in cells maintained in short-term suspension culture and in low-serum (LS). Both these culture conditions promote downregulation of cyclin A in control cells. In LS growth conditions E8 permits sustained cyclin A-associated kinase activity but not cyclin E-cdk2 activity. Cyclin A-cdk2 activity and, in part, cyclin A gene expression are regulated by the cdk inhibitor p27Kip1. Expression of this cdk inhibitor is also de-regulated in E8 cells, with high levels being detected under all culture conditions tested. These data suggest that the ability of BPV-4 E8 to transform NIH3T3 cells is associated with upregulation of cyclin A-associated kinase activity and de-regulated expression of the cdk inhibitor p27Kip1 and does not rely on down-regulation of p27Kip1 expression. Analysis of E8 mutants indicate that the hydrophilic 'tail' of the molecule (residues 31-42) is required for cell transformation, as assessed by anchorage-independent growth, while a form of E8 with expression restricted to the Endoplasmic Reticulum/cis-Golgi membranes by addition of a 'KDEL' retention signal revealed that the sub-cellular localization is an important determinant of E8 biological activity.


Asunto(s)
Papillomavirus Bovino 1/genética , Proteínas de Ciclo Celular , Ciclina A/biosíntesis , Proteínas Asociadas a Microtúbulos/biosíntesis , Proteínas Supresoras de Tumor , Células 3T3 , Animales , Papillomavirus Bovino 4 , Bovinos , Adhesión Celular , División Celular , Línea Celular Transformada , Ciclina A/genética , Inhibidor p27 de las Quinasas Dependientes de la Ciclina , Quinasas Ciclina-Dependientes/antagonistas & inhibidores , Quinasas Ciclina-Dependientes/biosíntesis , Inhibidores Enzimáticos/metabolismo , Regulación Viral de la Expresión Génica , Genes Reporteros , Genes ras , Humanos , Luciferasas/biosíntesis , Ratones , Sistemas de Lectura Abierta , Regiones Promotoras Genéticas , Proteínas Recombinantes de Fusión/biosíntesis , Activación Transcripcional , Transfección
9.
Biochim Biophys Acta ; 1242(1): 77-98, 1995 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-7542926

RESUMEN

Over the last few years, it has become clear that cell adhesion receptors function in signal transduction processes leading to the regulation of cell growth and differentiation. Signal transduction by both integrins and CAMs has been shown to involve activation of tyrosine kinases, while CAM signaling in neural cells involves G proteins as well. In the case of integrins, some of the downstream signaling events intersect with the Ras pathway, particularly the activation of MAP kinases. In fibroblasts, integrin mediated anchorage to the substratum regulates cell cycle traverse, while in epithelial cells, loss of anchorage can trigger programmed cell death. In many cell types, but particularly monocytic cells, integrin ligation has a profound impact on gene expression. Preliminary evidence also implicates CAMs and selectins in gene regulation. A consistent theme in signal transduction mediated by adhesion receptors concerns the role of the cytoskeleton. Integrin mediated signaling processes are interrupted by cytoskeletal disassembly. Identification of the APC and neurofibromatosis type 2 tumor suppressors suggest that cytoskeletal complexes also play a key role in signaling by cadherins and CD44, respectively. Thus, signaling by cell adhesion receptors may involve aspects that impinge on previously known signaling pathways including the RTK/Ras pathway and serpentine receptor/G protein pathways. However, novel aspects of signal transduction involving cytoskeletal assemblies may also be critical.


Asunto(s)
Cadherinas/fisiología , Moléculas de Adhesión Celular/fisiología , Integrinas/fisiología , Transducción de Señal , Animales , Proteínas Portadoras/fisiología , Citoesqueleto/fisiología , Regulación de la Expresión Génica , Humanos , Receptores de Hialuranos , Selectina L , Proteínas Tirosina Quinasas Receptoras/fisiología , Receptores de Superficie Celular/fisiología , Receptores Mensajeros de Linfocitos/fisiología
10.
Eur J Clin Nutr ; 43(3): 161-8, 1989 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-2731499

RESUMEN

Comparative studies of body weight, height, intracellular water representing cell mass, and age, and plasma concentrations of albumin, vitamins, trace elements and iron stores in Aboriginal children aged 6 to 13.5 years, from two rural Aboriginal settlements and one rural Caucasian school (Hawker) provided evidence of significant deficits in one of the Aboriginal settlements (Yalata). Yalata Aboriginal children had lower body weights and heights for age and lower intracellular water values. Plasma albumin, zinc, iron, alpha-tocopherol, beta-carotene and retinol concentrations were lower relative to the normally grown Aboriginal children at Nepabunna. The latter children did not differ from rural Caucasian children for the parameters studied. The reasons for this poorer growth at Yalata may reside in poor nutrition, or repeated bowel infection in postnatal life leading to malabsorption, or both. Limited observational evidence suggests that Giardiasis has a high prevalence at Yalata, and it has been shown elsewhere that Giardiasis is capable of inducing malabsorption with resulting nutritional deficiencies.


Asunto(s)
Trastornos de la Nutrición del Niño/epidemiología , Adolescente , Australia , Estatura , Agua Corporal/análisis , Peso Corporal , Niño , Trastornos de la Nutrición del Niño/etiología , Giardiasis/complicaciones , Giardiasis/epidemiología , Crecimiento , Humanos , Hierro/sangre , Síndromes de Malabsorción/etiología , Albúmina Sérica/análisis , Oligoelementos/sangre , Vitaminas/sangre
11.
J Biomech ; 18(2): 117-27, 1985.
Artículo en Inglés | MEDLINE | ID: mdl-3988781

RESUMEN

A smooth isolated, axisymmetric occlusion in a straight vascular tube is a tractable problem for pulsatile flow calculations via finite-difference approximations to the Navier-Stokes equation. Steady flow depends on the Reynolds number and two geometric parameters which describe the stenosis. The mere addition of a simple harmonic to the mean flow adds two more parameters. One is the reduced frequency, or Strokes number, and the other epsilon, the ratio of unsteady to steady flux. After describing steady stenosis flow examples, the dynamic patterns of pulsatile flow are illustrated indicating the inadequacy of basing hypotheses of atherosclerosis on mean (steady) flow.


Asunto(s)
Arteriopatías Oclusivas/fisiopatología , Hemodinámica , Arterias/fisiopatología , Arteriosclerosis/etiología , Humanos , Modelos Cardiovasculares , Reología
12.
Am J Occup Ther ; 42(6): 359-63, 1988 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-3394786

RESUMEN

One visual-perceptual test, four visual-motor tests, and a test of motor impairment were administered to 22 children with learning disabilities and 22 children without learning disabilities, aged 5 to 8 years. The children with learning disabilities were divided into two groups--"clumsy" and "nonclumsy"--based on their scores on the motor impairment test. It was hypothesized that the clumsy children with learning disabilities would score significantly lower on visual-perceptual and visual-motor tests than the nonclumsy children with learning disabilities who, in turn, would score significantly lower than the children without learning disabilities. It was further hypothesized that there would be a significant correlation between the degree of clumsiness and the degree of visual-perceptual and visual-motor deficit. Analysis of the data indicated that, as expected, the clumsy children with learning disabilities scored significantly lower than the children without learning disabilities (the control group). There was no significant difference between the clumsy and nonclumsy children with learning disabilities or between the nonclumsy children with learning disabilities and the control group. Degree of clumsiness significantly correlated with scores on four of five tests. Results are discussed in terms of subtypes of learning disabilities and sample size.


Asunto(s)
Discapacidades para el Aprendizaje/psicología , Destreza Motora , Percepción Visual , Análisis de Varianza , Niño , Preescolar , Femenino , Humanos , Discapacidades para el Aprendizaje/clasificación , Discapacidades para el Aprendizaje/rehabilitación , Masculino , Terapia Ocupacional
13.
Am J Occup Ther ; 44(7): 623-8, 1990 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-1696783

RESUMEN

The Sensory Integration and Praxis Tests (SIPT) (Ayres, 1989) were administered to 21 children with learning disabilities and 18 children without learning disabilities, aged 5 to 8 years. The children with learning disabilities were divided into two groups, clumsy and nonclumsy, on the basis of their scores on the Test of Motor Impairment (Stott, Moyes, & Henderson, 1984). It was hypothesized that the learning-disabled children in the clumsy group would score significantly lower than the learning-disabled children in the nonclumsy group on the six SIPT subtests that measure form and space perception and visual construction and that the nonclumsy learning-disabled children, in turn, would score significantly lower than the non-learning-disabled children. It was further hypothesized that there would be a significant correlation between the degree of clumsiness and the degree of visual-perceptual and constructional deficits. An analysis of the data indicated that both groups of learning-disabled children scored lower than the non-learning-disabled children on four of the six SIPT subtests. The clumsy and nonclumsy children with learning disabilities, however, differed from each other on only two subtests. The degree of clumsiness correlated significantly with three of the six subtests. The results are discussed in terms of variations in perceptual and motor skills related to subtypes of learning disabilities.


Asunto(s)
Discapacidades del Desarrollo/diagnóstico , Percepción de Forma/fisiología , Discapacidades para el Aprendizaje/diagnóstico , Pruebas Neuropsicológicas/instrumentación , Desempeño Psicomotor/fisiología , Percepción Espacial/fisiología , Niño , Preescolar , Discapacidades del Desarrollo/fisiopatología , Humanos , Discapacidades para el Aprendizaje/fisiopatología
14.
Health Care Strateg Manage ; 3(5): 14-9, 1985 May.
Artículo en Inglés | MEDLINE | ID: mdl-10271404

RESUMEN

A systematic approach to evaluating, planning and implementing new consumer services is necessary to ensure a successful program. Presented here are the three phases of the new service development process for hospitals--assessment, development, and execution--and the evolution and interaction among the health care delivery system, service, and market dimensions. Before, during, and after development, the need for hospital communications and effective marketing is also stressed.


Asunto(s)
Necesidades y Demandas de Servicios de Salud , Investigación sobre Servicios de Salud , Hospitales , Comercialización de los Servicios de Salud/métodos , Análisis de Sistemas
15.
Clin Hemorheol Microcirc ; 53(3): 267-79, 2013 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-22810050

RESUMEN

Hypertension is asymptomatic until late stages of pathogenesis, rendering an effective means of detection for early diagnosis essential. The current method of diagnosing hypertension requires two or more sphygmomanometric readings over two or more office visits, which potentially hinders early detection. Though retinopathy is an indicator of vascular damage, it generally presents in later stages of hypertension. Previous and related studies have suggested that the microvasculature in the bulbar conjunctiva may be a sensitive site to assess vasculopathy. Conjunctival microangiopathy was assessed using CAIM and reported on a severity index (SI). Images of the retinal fundus were taken via non-mydriatic fundus photography and graded using the Scheie scale in the same subjects to compare with CAIM. Conjunctival microangiopathy was significantly elevated in hypertensive subjects (SI = 5.35 ± 1.04, n = 20) compared to control subjects (SI = 1.75 ± 1.39, n = 8; p ≤ 0.05), and correlated with time since disease diagnosis (R² = 0.33). Hypertensive subjects with Grade 1 retinopathy displayed increased conjunctival microangiopathy (SI = 5.85 ± 0.90, n = 13) compared to those without retinopathy (SI = 4.43 ± 0.53, n = 7; p ≤ 0.05). These data indicate a possible pre-retinopathy time window during which conjunctival microangiopathy may indicate the risk of organ damage, supporting the hypothesis that the conjunctival microcirculation may serve as a platform for early detection and monitoring disease progression.


Asunto(s)
Conjuntiva/irrigación sanguínea , Angiopatías Diabéticas/diagnóstico , Retinopatía Diabética/diagnóstico , Fondo de Ojo , Hipertensión/diagnóstico , Adulto , Anciano , Angiopatías Diabéticas/patología , Retinopatía Diabética/patología , Femenino , Humanos , Hipertensión/fisiopatología , Masculino , Microcirculación , Microscopía por Video/métodos , Persona de Mediana Edad , Fotograbar
18.
J Heart Transplant ; 4(2): 229-31, 1985 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-3916491

RESUMEN

During the past three years, some 180 patients were assessed as potential candidates for a heart transplantation at Papworth Hospital. One hundred of them underwent the operation. This report presents the views of a social worker about the psychological and social aspects of heart transplantation based on personal experience with these patients. The different stages through which a heart transplant patient progresses, from the onset of his illness until resumption of a normal life will be considered, focusing on what this author believes to be some of the important aspects of these stages.


Asunto(s)
Trasplante de Corazón , Trasplante Homólogo/psicología , Adaptación Psicológica , Humanos , Ajuste Social , Servicio de Asistencia Social en Hospital
19.
Circ Res ; 36(2): 277-85, 1975 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-1116238

RESUMEN

Numerical simulations of pulsatile blood flow through a symmetrical branch modeling the aortic bifurcation were carried out to assess several hemodynamic theories of atherogenesis by comparing the distribution of hemodynamic variables with that of early lesions in arterial branches. Considerable spatial and temporal variations in wall shear were found when the flow was pulsatile; the highest values occurred at the convex corner on the outer wall of the branch and in the neighborhood of the flow divider tip, and the lowest shears were experienced by the outer wall of the daughter vessel a short distance distal to the corner. Transient flow reversal occurred almost everywhere in the branch, and a transient separated region was found corresponding to the low-shear region in the daughter vessel. The shear profiles and the calculated separated region were influenced to some degree by the extent of flow development at the branch inlet and markedly by the branch area ratio. All of the proposed hemodynamic promoters of atherosclerosis that were examined--high shear, low shear, and separation--were found at sites in the branch where lesions commonly develop. Comparisons with a steady-flow calculation at the same mean flow rate showed that the severity of all of these proposed hemodynamic determinants was increased by pulsatility.


Asunto(s)
Arteriosclerosis/fisiopatología , Velocidad del Flujo Sanguíneo , Hemodinámica , Modelos Biológicos , Pulso Arterial , Arterias , Matemática , Reología
20.
Exp Cell Res ; 224(1): 208-13, 1996 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-8612688

RESUMEN

It is clear that certain integrins can regulate the growth of tumors, probably by contributing to signal transduction processes. In the present study we have used HT29 human colon carcinoma cells stably transfected with human cDNA for the integrin alpha 5 subunit and studied the effects of alpha 5 expression on the induction of apoptosis. We observe that apoptosis can be triggered in HT29 cells by removal of serum and that this process can be suppressed by the stable expression of full-length integrin alpha 5 subunits. While the mechanism underlying this effect is still unclear, these observations suggest that the alpha 5 beta 1 integrin plays an important role in modulating tumor cell responses to growth factors and nutrients.


Asunto(s)
Antígenos CD/biosíntesis , Apoptosis , Neoplasias del Colon/metabolismo , Regulación Neoplásica de la Expresión Génica , Antígenos CD/genética , Ciclo Celular , Neoplasias del Colon/genética , Medio de Cultivo Libre de Suero , Células HT29 , Humanos , Integrina alfa5 , Transfección
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