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1.
Benef Microbes ; 13(3): 243-252, 2022 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-35866597

RESUMEN

We have previously shown that the probiotic Bifidobacterium breve strain Bif195 alleviates mucosal injury including ulcer formation in the upper intestine induced by non-steroid anti-inflammatory drugs (NSAIDs). Here, we report additional safety use of Bif195 in 126 healthy humans undergoing an exercise-induced intestinal permeability challenge in a double-blinded, placebo-controlled randomised 6-week intervention trial. Intestinal permeability was assessed by urinary lactulose/rhamnose (L/R) ratio. L/R ratio, plasma intestinal fatty acid binding protein (I-FABP) and gastrointestinal symptom rating scale (GSRS) questionnaire were measured resting and after a 1 h treadmill challenge, prior to and at the end of the intervention. To be able to compare the equivalence of resting state at baseline, of this cohort of well-trained subjects, to non-trained subjects, a cohort of 63 healthy and non-trained subjects (<2 h/week of endurance sports) was included. Study subjects (well-trained) were 35.7% women with a mean age and body mass index (in kg/m2) of 35.0 years and 24.8, respectively. There were no differences between the Bif195 and placebo groups in effects on L/R ratio, I-FABP and GSRS questionnaire score. In addition, there were no differences between Bif195 and placebo in number of adverse events and change in cytokines, liver or kidney biomarkers. The exercise model successfully induced intestinal permeability by statistically significantly increasing L/R ratio by ~100% (P<0.0001) and cytokines after the exercise challenge. No significant difference was found between well-trained and non-trained subjects in baseline resting L/R ratio. In conclusion, the reported cytoprotective effects of Bif195 are unlikely to be primarily related to small bowel permeability, and the safety of Bif195 in individuals with increased permeability is supported by the present data. ClinicalTrials.gov: NCT03027583.


Asunto(s)
Bifidobacterium breve , Probióticos , Adulto , Citocinas , Método Doble Ciego , Femenino , Humanos , Intestinos , Lactulosa , Masculino , Permeabilidad
3.
Nat Commun ; 11(1): 6036, 2020 11 27.
Artículo en Inglés | MEDLINE | ID: mdl-33247130

RESUMEN

Human activities are transforming grassland biomass via changing climate, elemental nutrients, and herbivory. Theory predicts that food-limited herbivores will consume any additional biomass stimulated by nutrient inputs ('consumer-controlled'). Alternatively, nutrient supply is predicted to increase biomass where herbivores alter community composition or are limited by factors other than food ('resource-controlled'). Using an experiment replicated in 58 grasslands spanning six continents, we show that nutrient addition and vertebrate herbivore exclusion each caused sustained increases in aboveground live biomass over a decade, but consumer control was weak. However, at sites with high vertebrate grazing intensity or domestic livestock, herbivores consumed the additional fertilization-induced biomass, supporting the consumer-controlled prediction. Herbivores most effectively reduced the additional live biomass at sites with low precipitation or high ambient soil nitrogen. Overall, these experimental results suggest that grassland biomass will outstrip wild herbivore control as human activities increase elemental nutrient supply, with widespread consequences for grazing and fire risk.


Asunto(s)
Biomasa , Pradera , Herbivoria/fisiología , Nitrógeno/análisis , Fósforo/análisis , Intervalos de Confianza , Fertilizantes , Factores de Tiempo
4.
J Therm Biol ; 60: 186-94, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27503732

RESUMEN

The tidal cycle around New Zealand results in spring low tides consistently occurring during the hottest part of the day (mid-afternoon) in north-eastern New Zealand, and during the cooler dawn/dusk periods in the north-west of the country. We hypothesised that due to mid-afternoon spring low tides, intertidal populations residing at north-eastern sites would show greater thermotolerance than their north-west conspecifics. To test this we used the marine gastropod, Lunella smaragda, which were collected from sites on both the East and West coasts of the Auckland region and exposed to an acute heat shock. Thermotolerance was measured as survivorship (LT50), drop down time (time to heat coma) and thermal stability of the anaerobic energy producing enzyme Tauropine dehydrogenase. Furthermore, temperature loggers were deployed at each site so as to record and compare thermal regimes among sites. A strong temperature spike associated with spring low tide was found at all sites, and maximal temperatures of all East coast sites were higher than West coast sites (in some case by up to 10°C). In terms of thermotolerance, mortality of L. smaragda occurred at 42°C leading to 100% mortality at 45°C. However, comparison of LT50 showed snails were equally thermotolerant regardless of site of collection. Similar results were found in TDH thermal stability with animals from all sites showing an approximately 80% decrease in enzyme activity after 10min exposure to 42°C. Whilst drop down times were different among sites these were correlated with animal size as opposed to site of collection. Thus, East coast populations of L. smaragda appear no more thermotolerant than their West coast counterparts. Such a result is concerning as maximal temperatures at East coast sites already exceed the LT50 values of L. smaragda recorded in the lab suggesting these populations have less of a thermal safety margin.


Asunto(s)
Aclimatación , Respuesta al Choque Térmico , Caracoles/fisiología , Animales , Estabilidad de Enzimas , Calor , Nueva Zelanda , Estaciones del Año , Caracoles/enzimología , Temperatura
6.
Diabet Med ; 31(11): 1460-7, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24766227

RESUMEN

AIMS: To investigate the prevalence of symptomatic obstructive sleep apnoea in unselected patients with Type 2 diabetes referred to a tertiary diabetes clinic. METHODS: In a cross-sectional design, all newly referred patients were offered a stepwise screening for obstructive sleep apnoea with: (1) The Berlin questionnaire; then, if indicative: (2) overnight home monitoring with the ApneaLink™ device. Patients with an apnoea-hypopnoea index ≥ 5/h were offered referral for diagnostic polygraphy and treatment initiation. RESULTS: A total of 200 patients participated (61% men; age 59.6 ± 10.5 years, diabetes duration 8.3 ± 6.3 years and BMI 31.7 ± 6.7 kg/m²). According to the questionnaire, 106 patients showed 'high risk' of obstructive sleep apnoea, and 72 of these were referred to polygraphy based on ApneaLink screening corresponding to a prevalence of symptomatic obstructive sleep apnoea of 39%. Patients with symptomatic obstructive sleep apnoea had significantly higher BMI, poorer glycaemic control and lower plasma HDL cholesterol levels as compared with patients unlikely to have obstructive sleep apnoea. The groups were not different with respect to sex, age, diabetes duration, blood pressure, diabetic complications or medication use. In multiple regression analyses, age, BMI and HDL cholesterol levels were all significant, independent predictors of obstructive sleep apnoea. CONCLUSIONS: At least one third of people with Type 2 diabetes referred to a diabetes clinic in Denmark has symptomatic obstructive sleep apnoea. Our data suggest higher age, a compromised plasma lipid profile and a more obese phenotype in patients with Type 2 diabetes who have obstructive sleep apnoea, highlighting the need to focus on screening and treatment of obstructive sleep apnoea in these patients.


Asunto(s)
Diabetes Mellitus Tipo 2/complicaciones , Apnea Obstructiva del Sueño/complicaciones , Factores de Edad , Anciano , Índice de Masa Corporal , Estudios de Cohortes , Estudios Transversales , Dinamarca/epidemiología , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/terapia , Dislipidemias/complicaciones , Estudios de Factibilidad , Femenino , Hemoglobina Glucada/análisis , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico , Sobrepeso/complicaciones , Prevalencia , Factores de Riesgo , Índice de Severidad de la Enfermedad , Factores Sexuales , Apnea Obstructiva del Sueño/diagnóstico , Apnea Obstructiva del Sueño/epidemiología , Apnea Obstructiva del Sueño/fisiopatología , Ronquido/complicaciones , Centros de Atención Terciaria
7.
BJOG ; 120(9): 1123-32, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23682628

RESUMEN

OBJECTIVES: To investigate whether elective caesarean section before 39 completed weeks of gestation increases the risk of adverse neonatal or maternal outcomes. DESIGN: Randomised controlled multicentre open-label trial. SETTING: Seven Danish tertiary hospitals from March 2009 to June 2011. POPULATION: Women with uncomplicated pregnancies, a single fetus, and a date of delivery estimated by ultrasound scheduled for delivery by elective caesarean section. METHODS: Perinatal outcomes after elective caesarean section scheduled at a gestational age of 38 weeks and 3 days versus 39 weeks and 3 days (in both groups ±2 days). MAIN OUTCOME MEASURES: The primary outcome was neonatal intensive care unit (NICU) admission within 48 hours of birth. Secondary outcomes were neonatal depression, NICU admission within 7 days, NICU length of stay, neonatal treatment, and maternal surgical or postpartum adverse events. RESULTS: Among women scheduled for elective caesarean section at 38⁺³ weeks 88/635 neonates (13.9%) were admitted to the NICU, whereas in the 39⁺³ weeks group 76/637 neonates (11.9%) were admitted (relative risk [RR] 0.86, 95% confidence interval [95% CI] 0.65-1.15). Neonatal treatment with continuous oxygen for more than 1 day (RR 0.31; 95% CI 0.10-0.94) and maternal bleeding of more than 500 ml (RR 0.79; 95% CI 0.63-0.99) were less frequent in the 39 weeks group, but these findings were insignificant after adjustment for multiple comparisons. The risk of adverse neonatal or maternal outcomes, or a maternal composite outcome (RR 1.1; 95% CI 0.79-1.53) was similar in the two intervention groups. CONCLUSIONS: This study found no significant reduction in neonatal admission rate after ECS scheduled at 39 weeks compared with 38 weeks of gestation.


Asunto(s)
Cesárea/estadística & datos numéricos , Depresión Posparto/epidemiología , Procedimientos Quirúrgicos Electivos/estadística & datos numéricos , Edad Gestacional , Unidades de Cuidado Intensivo Neonatal/estadística & datos numéricos , Tiempo de Internación/estadística & datos numéricos , Adulto , Cesárea/efectos adversos , Dinamarca/epidemiología , Procedimientos Quirúrgicos Electivos/efectos adversos , Femenino , Humanos , Recién Nacido , Embarazo , Resultado del Embarazo , Medición de Riesgo , Factores de Tiempo
8.
Bone Marrow Transplant ; 48(9): 1185-91, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23524638

RESUMEN

We report the results of non-myeloablative (NM) and myeloablative (MA) conditioning for haematopoietic cell transplantation in 207 consecutive AML patients at a single institution. A total of 122 patients were transplanted in first CR (CR1) and 67 in second CR (CR2). MA conditioning was given to 60 patients in CR1 and 50 in CR2. NM conditioning was given to 62 patients in CR1 and 17 patients in CR2. MA patients in CR1 experienced more acute GVHD than NM patients, 60.5% versus 22.9%, but the 5-year post transplant cumulative TRM was not different. Relapse incidence at 5 years in CR1 patients was 23.7% which is not statistically different from 28.5% in NM patients. Leukaemia-free survival at 5 years in CR1 patients was 57.7% after MA conditioning and 58.3% after NM conditioning. No statistical difference in overall 5-year survival after MA or NM conditioning was observed in CR1 patients (63.9 versus 64%) and CR2 patients (51.2 versus 64.7%). Durable remission can be obtained in older patients with AML in remission after NM conditioning, which may also be applicable to younger patients.


Asunto(s)
Trasplante de Células Madre Hematopoyéticas/métodos , Leucemia Mieloide Aguda/terapia , Acondicionamiento Pretrasplante/métodos , Adolescente , Adulto , Terapia Combinada , Ciclofosfamida/administración & dosificación , Femenino , Humanos , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/radioterapia , Leucemia Mieloide Aguda/cirugía , Donadores Vivos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/patología , Estudios Retrospectivos , Sobrevivientes , Trasplante Homólogo , Irradiación Corporal Total , Adulto Joven
9.
Scand J Immunol ; 76(2): 141-50, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22536994

RESUMEN

Minor histocompatibility antigens (mHags) encoded by the Y-chromosome (H-Y-mHags) are known to play a pivotal role in allogeneic haematopoietic cell transplantation (HCT) involving female donors and male recipients. We present a new H-Y-mHag, YYNAFHWAI (UTY(139-147)), encoded by the UTY gene and presented by HLA-A*24:02. Briefly, short peptide stretches encompassing multiple putative H-Y-mHags were designed using a bioinformatics predictor of peptide-HLA binding, NetMHCpan. These peptides were used to screen for peptide-specific HLA-restricted T cell responses in peripheral blood mononuclear cells obtained post-HCT from male recipients of female donor grafts. In one of these recipients, a CD8+ T cell response was observed against a peptide stretch encoded by the UTY gene. Another bioinformatics tool, HLArestrictor, was used to identify the optimal peptide and HLA-restriction element. Using peptide/HLA tetramers, the specificity of the CD8+ T cell response was successfully validated as being HLA-A*24:02-restricted and directed against the male UTY(139-147) peptide. Functional analysis of these T cells demonstrated male UTY(139-147) peptide-specific cytokine secretion (IFNγ, TNFα and MIP-1ß) and cytotoxic degranulation (CD107a). In contrast, no responses were seen when the T cells were stimulated with patient tumour cells alone. CD8+ T cells specific for this new H-Y-mHag were found in three of five HLA-A*24:02-positive male recipients of female donor HCT grafts available for this study.


Asunto(s)
Antígenos de Histocompatibilidad Menor/inmunología , Proteínas Nucleares/inmunología , Secuencia de Aminoácidos , Células Sanguíneas/trasplante , Linfocitos T CD8-positivos/inmunología , Epítopos/inmunología , Femenino , Antígeno HLA-A24/inmunología , Humanos , Masculino , Proteínas Nucleares/química , Trasplante Homólogo
10.
J Appl Microbiol ; 111(2): 338-49, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21624021

RESUMEN

AIMS: To gain an understanding of the environmental factors that affect the growth of the bacterium Sporosarcina pasteurii, the metabolism of the bacterium and the calcium carbonate precipitation induced by this bacterium to optimally implement the biological treatment process, microbial induced calcium carbonate precipitation (MICP), in situ. METHODS AND RESULTS: Soil column and batch tests were used to assess the effect of likely subsurface environmental factors on the MICP treatment process. Microbial growth and mineral precipitation were evaluated in freshwater and seawater. Environmental conditions that may influence the ureolytic activity of the bacteria, such as ammonium concentration and oxygen availability, as well as the ureolytic activities of viable and lysed cells were assessed. Treatment formulation and injection rate, as well as soil particle characteristics are other factors that were evaluated for impact on uniform induction of cementation within the soils. CONCLUSIONS: The results of the study presented herein indicate that the biological treatment process is equally robust over a wide range of soil types, concentrations of ammonium chloride and salinities ranging from distilled water to full seawater; on the time scale of an hour, it is not diminished by the absence of oxygen or lysis of cells containing the urease enzyme. SIGNIFICANCE AND IMPACT OF STUDY: This study advances the biological treatment process MICP towards field implementation by addressing key environmental hurdles faced with during the upscaling process.


Asunto(s)
Carbonato de Calcio/química , Microbiología del Suelo , Sporosarcina/crecimiento & desarrollo , Precipitación Química , Medios de Cultivo/química , Agua Dulce/química , Agua Dulce/microbiología , Agua de Mar/química , Agua de Mar/microbiología , Suelo/química , Sporosarcina/metabolismo , Urea/análisis , Ureasa/metabolismo
11.
Am J Physiol Endocrinol Metab ; 299(5): E752-63, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20739510

RESUMEN

Physical inactivity is a risk factor for insulin resistance. We examined the effect of 9 days of bed rest on basal and insulin-stimulated expression of genes potentially involved in insulin action by applying hypothesis-generating microarray in parallel with candidate gene real-time PCR approaches in 20 healthy young men. Furthermore, we investigated whether bed rest affected DNA methylation in the promoter region of the peroxisome proliferator-activated receptor-γ coactivator-1α (PPARGC1A) gene. Subjects were reexamined after 4 wk of retraining. We found that bed rest induced insulin resistance and altered the expression of more than 4,500 genes. These changes were only partly normalized after 4 wk of retraining. Pathway analyses revealed significant downregulation of 34 pathways, predominantly those of genes associated with mitochondrial function, including PPARGC1A. Despite induction of insulin resistance, bed rest resulted in a paradoxically increased response to acute insulin stimulation in the general expression of genes, particularly those involved in inflammation and endoplasmatic reticulum (ER) stress. Furthermore, bed rest changed gene expressions of several insulin resistance and diabetes candidate genes. We also observed a trend toward increased PPARGC1A DNA methylation after bed rest. We conclude that impaired expression of PPARGC1A and other genes involved in mitochondrial function as well as a paradoxically increased response to insulin of genes involved in inflammation and ER stress may contribute to the development of insulin resistance induced by bed rest. Lack of complete normalization of changes after 4 wk of retraining underscores the importance of maintaining a minimum of daily physical activity.


Asunto(s)
Reposo en Cama , Resistencia a la Insulina/fisiología , Músculo Esquelético/fisiología , Adulto , Metilación de ADN , Epigénesis Genética , Perfilación de la Expresión Génica/métodos , Regulación de la Expresión Génica , Técnica de Clampeo de la Glucosa , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/fisiología , Humanos , Resistencia a la Insulina/genética , Masculino , Análisis de Secuencia por Matrices de Oligonucleótidos , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , ARN/química , ARN/genética , Estadísticas no Paramétricas , Factores de Transcripción/genética , Factores de Transcripción/fisiología , Adulto Joven
12.
Rev Stomatol Chir Maxillofac ; 110(1): e1-4, 2009 Feb.
Artículo en Francés | MEDLINE | ID: mdl-19108856

RESUMEN

INTRODUCTION: Sialendoscopy and sialo-MRI enable diagnosis of salivary gland obstructive pathologies, such as lithiasis, stenosis and dilatations. Therefore, a classification of these pathologies is needed, allowing large series comparisons, for better diagnosis and treatment of salivary pathologies. MATERIAL AND METHODS: With help from people from the European Sialendoscopy Training Center (ESTC), the results of sialographies, sialoMRI and sialendoscopies, a comprehensive classification of obstructive salivary pathologies is described, based on the absence or presence of lithiasis (L), stenosis (S) and dilatation (D) ("LSD" classification). DISCUSSION: It appears that a classification of salivary gland obstructive pathologies should be described. We hope it will be widely used and of course criticized to be improved and to compare the results of salivary gland diagnostic methods, such as sialography and sialendoscopy and also the results and indications for salivary gland therapeutic methods, such as lithotripsy, sialendoscopy and/or open surgery.


Asunto(s)
Cálculos del Conducto Salival/clasificación , Cálculos de las Glándulas Salivales/clasificación , Enfermedades de las Glándulas Salivales/clasificación , Constricción Patológica/clasificación , Dilatación Patológica/clasificación , Endoscopía , Humanos , Imagen por Resonancia Magnética , Conductos Salivales/patología , Sialografía
13.
Rev Stomatol Chir Maxillofac ; 109(4): 233-6, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18774150

RESUMEN

INTRODUCTION: Sialendoscopy and sialoMRI enables diagnosis of salivary gland obstructive pathologies, such as lithiasis, stenosis, and dilatations. Therefore, a classification of these pathologies is needed, allowing large series comparisons, for better diagnosis and treatment of salivary pathologies. MATERIAL AND METHODS: With help from people from the European Sialendoscopy Training Center (ESTC), the results of sialographies, sialoMRI and sialendoscopies, a comprehensive classification of obstructive salivary pathologies is described, based on the absence or presence of lithiasis (L), stenosis (S), and dilatation (D) ("LSD" classification). DISCUSSION: It appears that a classification of salivary gland obstructive pathologies should be described. We hope it will be widely used and of course criticized to be improved and to compare the results of salivary gland diagnostic methods, such as sialography and sialendoscopy, and also the results and indications for salivary gland therapeutic methods, such as lithotripsy, sialendoscopy, and/or open surgery.


Asunto(s)
Cálculos de las Glándulas Salivales/clasificación , Enfermedades de las Glándulas Salivales/clasificación , Constricción Patológica/clasificación , Dilatación Patológica/clasificación , Endoscopía , Humanos , Imagen por Resonancia Magnética , Cálculos del Conducto Salival/clasificación , Conductos Salivales/patología , Sialografía
14.
Dentomaxillofac Radiol ; 33(5): 351-3, 2004 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15585816

RESUMEN

Mylohyoid herniation of the sublingual gland has been a frequent finding at dissection of adult human cadavers and at retrospective studies of computed tomography (CT) and magnetic resonance imaging (MRI) of the floor of the mouth. Even so, very few clinical reports exist. The present report describes an adolescent boy with a suspected submental tumour, which at MRI was shown to be caused by a mylohyoid hernia of part of an enlarged, but otherwise normal sublingual gland.


Asunto(s)
Imagen por Resonancia Magnética , Enfermedades Musculares/diagnóstico , Músculos del Cuello/patología , Enfermedades de las Glándulas Salivales/diagnóstico , Glándula Sublingual/patología , Adolescente , Medios de Contraste , Diagnóstico Diferencial , Gadolinio DTPA , Hernia/diagnóstico , Humanos , Masculino
16.
Acta Paediatr ; 92(5): 569-73, 2003 May.
Artículo en Inglés | MEDLINE | ID: mdl-12839286

RESUMEN

AIM: To investigate whether inherited factors, other than those already known, influence the bilirubin concentration in neonates of northern European descent, by comparison of monozygotic and dizygotic twins with respect to differences in the plasma bilirubin concentrations between the twins. METHODS: 77 healthy pairs of twins of the same gender with a gestational age > or = 250 d and of northern European descent were included. Fourth postnatal day blood sampling was done. A multiple linear regression analysis was carried out with the difference in serum bilirubin concentration between the twins as the independent factor, and zygosity, gender, gestational age, postnatal age, maternal smoking, ABO blood-type incompatibility, and the differences between the twins in blood haemoglobin concentration, formula feeding and weight loss as dependent factors. RESULTS: 27 pairs of twins were monozygotic and 50 pairs dizygotic. The analysis showed that the difference in serum bilirubin concentration between the twins was dependent on whether the twins were monozygotic or dizygotic, i.e. the estimated difference in serum bilirubin concentration between the monozygotic twins was 17.8 micromol l(-1) [SE 6.6 micromol l(-1), p = 0.02, 95% confidence interval (95% CI) 3.4, 32.3 micromol l(-1)] less than the difference between the dizygotic twins, adjusted for the above-mentioned potential confounders. The difference in serum bilirubin concentration between the twins was positively correlated to the difference in weight loss (%) between the twins (adjusted estimate 5.2 micromol l(-1), SE 2.1 micromol l(-1) , p = 0.01, 95% CI 1.2, 9.3 micromol l(-1)). CONCLUSION: In a population of northern European descent, other genetic factors than gender and ABO blood type were significant for the plasma bilirubin concentration in healthy infants.


Asunto(s)
Bilirrubina/sangre , Bilirrubina/genética , Ictericia Neonatal/sangre , Ictericia Neonatal/genética , Gemelos Dicigóticos/genética , Gemelos Monocigóticos/genética , Sistema del Grupo Sanguíneo ABO/genética , Peso al Nacer/genética , Europa (Continente)/etnología , Femenino , Edad Gestacional , Humanos , Recién Nacido , Masculino , Factores Sexuales
17.
Cell Prolif ; 33(6): 381-95, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11101010

RESUMEN

The microenvironmental changes in the bone marrow, spleen and liver during progression of the transplantable promyelocytic leukaemia in the Brown Norwegian rat (BNML) have been studied. We used flow cytometry to estimate cellular hypoxia and proliferation based on in vivo pulse-labelling with a mixture of 2-nitroimidazole linked to theophylline (NITP) and bromodeoxyuridine (BrdUrd). The leukaemic cells were identified with the RM124 antibody. In rats inoculated with leukaemic cells the fraction of RM124+ cells was significantly increased from day 20 onwards in the spleen and from day 27 in the bone marrow and liver, reaching a level of 65-87% in these organs at day 32. At day 32, the NITP+ fraction of RM124+ cells had increased significantly in the bone marrow and spleen to 88% and 90%, respectively. The corresponding fractions of NITP+ normal cells reached 63% and 65%, respectively. From day 13 to day 32, the DNA-synthesizing (BrdUrd+) fraction of RM124+ cells in the bone marrow decreased significantly from 52% to 25%, and of normal cells from about 20% to 6%. In the bone marrow and spleen at day 27 and 32, the S-phase and G2/M-phase fractions according to DNA content were higher for the NITP+ than for the NITP- cells. This could partly be explained by an impaired cell cycle progression due to hypoxia. Nevertheless, we found indications of leukaemic cells that were simultaneously labelled with NITP and BrdUrd, in the bone marrow and spleen. These latter findings suggest that in contrast to normal cells some of the leukaemic cells can proliferate even during hypoxia, and this subpopulation may consequently renew and expand the leukaemic cell load.


Asunto(s)
Leucemia Mieloide/fisiopatología , Oxígeno/metabolismo , Enfermedad Aguda , Animales , División Celular , Hipoxia de la Célula , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Leucemia Mieloide/metabolismo , Ratas , Ratas Endogámicas BN , Células Tumorales Cultivadas
18.
Int J Cancer ; 88(3): 464-8, 2000 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-11054677

RESUMEN

Glutathione plays an important role in drug resistance of tumor cells and in their ability to resist oxidative stress. Improved salvage of glutathione can be obtained through increased activity of gamma-glutamyltransferase (GGT), which is of importance in the maintenance of cellular glutathione homeostasis. We investigated the regulation of GGT in 2 cisplatin-resistant and 1 cisplatin-sensitive colon carcinoma cell lines. Enzyme activity was induced in all 3 cell lines after acute exposure to cisplatin. The elevation was significantly higher in sensitive cells (3.3-fold) than in resistant (1.6- to 1.7-fold) cells. Exposure of cells to oxidative stress generated by menadione also resulted in enzyme induction but only in cisplatin-sensitive cells. Addition of anti-oxidants had different effects on the 2 inductions: N-acetylcysteine blocked the induction of both cisplatin and menadione, whereas catalase and glutathione-ester blocked only the menadione induction. Glutathione depletion alone was not sufficient to induce GGT in these cells. The data show that GGT is regulated by multiple mechanisms during anti-tumor drug treatment and oxidative stress and that reactive oxygen species were involved in the menadione, but not cisplatin, induction of the enzyme.


Asunto(s)
Antineoplásicos/farmacología , Cisplatino/farmacología , Neoplasias del Colon/tratamiento farmacológico , Estrés Oxidativo , gamma-Glutamiltransferasa/metabolismo , Butionina Sulfoximina/farmacología , Neoplasias del Colon/metabolismo , Resistencia a Antineoplásicos , Glutatión/análisis , Humanos , Especies Reactivas de Oxígeno/metabolismo , Células Tumorales Cultivadas
19.
Arch Toxicol ; 74(6): 308-12, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11005676

RESUMEN

In vitro rates of metabolism and Michaelis-Menten constants were determined for 25 different C6 to C10 hydrocarbons using rat liver slices in a vial head-space equilibration system. The rates of metabolism were compared with steady-state levels obtained in vivo in the same strains of rats after inhalation. Aromates were metabolized at a higher rate than naphthenes n-alkanes, isoalkanes and 1-alkenes. The aromates showed, in contrast to the other hydrocarbons investigated, increased metabolism with increasing number of carbon atoms up to C8 (o-xylene, the most extensively metabolized compound). The in vivo steady-state concentrations of the aromates in blood were inversely related to the in vitro efficiency of their metabolism. This explains the pattern of blood levels observed for the C6 to C10 aromates in the rat after inhalation, with o-xylene demonstrating the lowest concentration. In general, the extent of tissue metabolism of the investigated hydrocarbons might be of greater importance for their body distribution than their lipophilicity, especially for the highly metabolized compounds. The high in vitro intrinsic liver clearances found for the aromates indicate a flow-dependent metabolism of these hydrocarbons in vivo. The head-space liver slice equilibration system seems to work adequately for metabolic studies of hydrocarbons with different volatility and water solubility.


Asunto(s)
Hidrocarburos/metabolismo , Hígado/metabolismo , Petróleo , Animales , Biotransformación , Cromatografía de Gases , Técnicas In Vitro , Masculino , Ratas , Ratas Sprague-Dawley
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