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1.
J Orthop Res ; 32(3): 413-22, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24249665

RESUMEN

We assessed the variation in proximal femoral canal shape and its association with geometric and demographic parameters in primary hip OA. In a retrospective cohort study, the joint geometry of the proximal femur was evaluated on radiographs and corresponding CT scans of 345 consecutive patients with end-stage hip OA. Active shape modeling (ASM) was performed to assess the variation in endosteal shape of the proximal femur. To identify natural groupings of patients, hierarchical cluster analysis of the shape modes was used. ASM identified 10 independent shape modes accounting for >96% of the variation in proximal femoral canal shape within the dataset. Cluster analysis revealed 10 specific shape clusters. Significant differences in geometric and demographic parameters between the clusters were observed. ASM and subsequent cluster analysis have the potential to identify specific morphological patterns of the proximal femur despite the variability in proximal femoral anatomy. The study identified patterns of proximal femoral canal shape in hip OA that allow a comprehensive classification of variation in shape and its association with joint geometry. Our data may improve future stem designs that will optimize stem fit and simultaneously allow individual restoration of hip biomechanics.


Asunto(s)
Fémur/patología , Osteoartritis de la Cadera/patología , Adulto , Anciano , Variación Anatómica , Análisis por Conglomerados , Femenino , Fémur/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Modelos Teóricos , Osteoartritis de la Cadera/clasificación , Osteoartritis de la Cadera/diagnóstico por imagen , Estudios Retrospectivos , Tomografía Computarizada por Rayos X
2.
Bone ; 53(1): 188-93, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23220597

RESUMEN

PURPOSE: There is a continuing need to improve the prediction of hip fractures to identify those at highest risk, enabling cost-effective use of preventative therapies. METHODS: The aim of this work was to validate an innovative imaging biomarker for hip fracture by modelling the shape and texture of the proximal femur assessed from dual energy X-ray absorptiometry (DXA) scans. Scans used were acquired at baseline from elderly patients participating in a prospective, placebo-controlled fracture prevention study of the bisphosphonate, clodronate. 182 subjects who subsequently suffered a hip fracture were age, weight and height matched with two controls who did not suffer a fracture during a median 4-year follow-up period. Logistic regression was used to test if variables were good predictors of fracture and adjust for bone mineral density (BMD). RESULTS: Shape mode 2, reflecting variability in neck-shaft angle, neck width and the size of both trochanters (0.81 (OR), 0.68-0.97 (CI), 0.024 (P)), and appearance mode 6, recording grey-level contrast (1.33, 1.11-1.59, 0.002), were significant predictors of hip fracture and remained so after adjustment for BMD (shape mode 2 (0.77, 0.64-0.93, 0.006), appearance mode 6 (1.32, 1.10-1.59, 0.003)). Receiver Operating Curve analysis showed the combination of shape mode 2, appearance mode 6 and BMD was 3% better than any single predictor. CONCLUSION: Variables derived from shape and appearance models gave a prediction of fracture comparable to BMD and in combination with BMD gave an improvement in the prediction of hip fracture that could predict an additional 2000 hip fracture cases per year in the UK, potentially saving more than £20 million per year and 10,000 cases in the US.


Asunto(s)
Fracturas de Cadera/patología , Modelos Biológicos , Anciano , Densidad Ósea , Estudios de Cohortes , Humanos , Placebos
3.
Mol Biol Rep ; 39(12): 9989-94, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22744429

RESUMEN

Delayed gastric emptying symptoms are often reported after chemotherapy. This study aims to characterise the effects of chemotherapy on gastric neuro-muscular function. Patients undergoing elective surgery for oesophago-gastric cancer were recruited. Acetylcholinesterase, nNOS, ghrelin receptor and motilin expressions were studied in gastric sections from patients receiving no chemotherapy (n = 3) or oesophageal (n = 2) or gastric (n = 2) chemotherapy. A scoring system quantified staining intensity (0-3; no staining to strong). Stomach sections were separately suspended in tissue baths for electrical field stimulation (EFS) and exposure to erythromycin or carbachol; three patients had no chemotherapy; four completed cisplatin-based chemotherapy within 6 weeks prior to surgery. AChE expression was markedly decreased after chemotherapy (scores 2.3 ± 0.7, 0.5 ± 0.2 and 0 ± 0 in non-chemotherapy, oesophageal- and gastric-chemotherapy groups (p < 0.03 each) respectively. Ghrelin receptor and motilin expression tended to increase (ghrelin: 0.7 ± 0.4 vs 2.0 ± 0.4 and 1.2 ± 0.2 respectively; p = 0.04 and p = 0.2; motilin: 0.7 ± 0.5 vs 2.2 ± 0.5 and 2.0 ± 0.7; p = 0.06 and p = 0.16). Maximal contraction to carbachol was 3.7 ± 0.7 g and 1.9 ± 0.8 g (longitudinal muscle) and 3.4 ± 0.4 g and 1.6 ± 0.6 (circular) in non-chemotherapy and chemotherapy tissues respectively (p < 0.05 each). There were loss of AChE and reduction in contractility to carbachol. The tendency for ghrelin receptors to increase suggests an attempt to upregulate compensating systems. Our study offers a mechanism by which chemotherapy markedly alters neuro-muscular gastric function.


Asunto(s)
Adenocarcinoma/fisiopatología , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Neoplasias Esofágicas/fisiopatología , Músculo Liso/inervación , Neoplasias Gástricas/fisiopatología , Estómago/fisiopatología , Acetilcolinesterasa/metabolismo , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/metabolismo , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Capecitabina , Carbacol/farmacología , Quimioterapia Adyuvante , Agonistas Colinérgicos/farmacología , Cisplatino/administración & dosificación , Desoxicitidina/administración & dosificación , Desoxicitidina/análogos & derivados , Epirrubicina/administración & dosificación , Neoplasias Esofágicas/tratamiento farmacológico , Neoplasias Esofágicas/metabolismo , Femenino , Fluorouracilo/administración & dosificación , Fluorouracilo/análogos & derivados , Ganglios Autónomos/patología , Vaciamiento Gástrico/efectos de los fármacos , Mucosa Gástrica/metabolismo , Humanos , Técnicas In Vitro , Masculino , Persona de Mediana Edad , Contracción Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/patología , Terapia Neoadyuvante , Estómago/efectos de los fármacos , Estómago/patología , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/metabolismo
4.
Mol Biol Rep ; 38(8): 4833-8, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21132531

RESUMEN

Ghrelin, an orexigenic hormone of gastric origin that stimulates growth hormone secretion, may modulate inflammation. This experimental study examines the effect of ghrelin on NFκB (p65 subunit), a transcriptional factor involved in inflammation on a human B-lymphocyte cell (WILCL). After confirming the expression of ghrelin receptor protein using western blotting the cells were transferred to wells maintaining a density of 1 × 10(6) cells per ml and a proportion activated with phytohaemagluttinin. Activated and resting cells were exposed to octanoyl-, desoctanoyl ghrelin and a non-peptide ghrelin agonist (Pfizer CP-464709) in increasing concentrations for 6 h. Cell protein extracts were analyzed for NFκB activation using Trans AM NFκB p65 assay. IL-6, IL-8, IL-10, IL-13 and TNFα were measured in the media using Lincoplex human cytokine assay. In octanoyl ghrelin treated resting cells, NFκB activity (Optical Density OD(450 nm)) (mean ± SEM) in control cells was 0.42 ± 0.10 and increased to 0.61 ± 0.20 (P = 0.044), 0.54 ± 0.10 (P = 0.043), 0.52 ± 0.08 at 1, 10 and 100 nM concentrations respectively. No effect was detected with desoctanoyl ghrelin or ghrelin agonist and no specific change in cytokine production. In conclusion, Octanoyl ghrelin increased NFκB activation by up to 50% in a B-lymphocyte cell line suggesting an effect on the inflammatory process.


Asunto(s)
Linfocitos B/efectos de los fármacos , Linfocitos B/metabolismo , Ghrelina/farmacología , FN-kappa B/metabolismo , Western Blotting , Línea Celular , Medios de Cultivo/farmacología , Citocinas/metabolismo , Humanos , Activación de Linfocitos/efectos de los fármacos , Receptores de Ghrelina/agonistas , Receptores de Ghrelina/metabolismo
5.
BMJ Case Rep ; 20112011 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-22707549

RESUMEN

A 71-year-old female presented with recurrent sigmoid volvulus. In the current admission, her symptoms were not settling on conservative measures and subsequently went on to have laparotomy. During laparotomy, along with the sigmoid volvulus, there was associated gallbladder torsion. About 500 cases of gallbladder volvulus have been published in literature, however, in our literature search, the authors did not find any similar published case presenting with volvulus involving the gallbladder and the sigmoid colon at the same time. This patient went onto have cholecystectomy and sigmoid colectomy and had a good postoperative recovery and was discharged on the tenth postoperative day. At 6-week postoperative follow-up, she was doing well with no specific concerns.


Asunto(s)
Enfermedades de la Vesícula Biliar/complicaciones , Vólvulo Intestinal/complicaciones , Enfermedades del Sigmoide/complicaciones , Anomalía Torsional/complicaciones , Anciano , Femenino , Humanos
6.
Mol Biol Rep ; 37(8): 3697-701, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20195769

RESUMEN

Octanoylation of the gastric peptide ghrelin produces an active isoform that regulates appetite and other metabolic functions. Acylated ghrelin is present in the gastrointestinal tract suggesting that octanoylation may occur in these tissues and thereby affect the acylated ghrelin in the systemic circulation. In this study blood samples were collected simultaneously from portal, arterial, peripheral venous and central venous compartments from patients undergoing laparotomy. ELISA and high sensitivity Bioplex was used to measure the concentration of acylated and des acyl ghrelin. We found median (95% confidence interval (CI)) plasma acylated ghrelin (pg/ml) was 35.8 (30.0-59.6) in the portal compartment compared to 51.5 (37.6-74.8; P < 0.05, n = 11) in the arterial, 39.3 (33.3-56.3) in the portal compartment compared to 55.0 (48.5-77.0; P < 0.001, n = 12) in the peripheral venous and 36.0 (33.1-57.4) in the portal compartment compared to 48.9 (43.3-65.6; P < 0.01, n = 15) in the central venous compartment. Median (95% CI) plasma des acyl ghrelin levels (pg/ml) was 173 (125-220) in the portal compartment compared to 136 (99.3-125; P < 0.001, n = 14)in the arterial, 186 (136-233) in the portal compartment compared to 149 (111-190; P < 0.01, n = 15) in the peripheral venous and 171 (140-208) in the portal compartment compared to 152 (119-175; P < 0.01, n = 15) the central venous compartment. We conclude that plasma acylated ghrelin concentration was significantly lower in portal compared with the systemic compartments whilst plasma des acyl ghrelin was significantly higher in portal compared with systemic compartments. These findings suggest that the liver could be involved in the regulation of circulating ghrelin.


Asunto(s)
Circulación Sanguínea/fisiología , Ghrelina/sangre , Sistema Porta/metabolismo , Demografía , Femenino , Humanos , Masculino , Persona de Mediana Edad
7.
Colorectal Dis ; 12(5): 416-9, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-19220377

RESUMEN

OBJECTIVE: Colorectal cancer (CRC) screening aims to detect asymptomatic disease and thus provide the opportunity for early diagnosis and treatment. This study assesses the prevalence of significant symptoms in patients found to have CRC detected through the NHS National Bowel Cancer Screening Programme (NHS NBCSP) pilots. METHOD: All patients in the NHS NBCSP pilots with a positive faecal occult blood completed a standardized symptomatology questionnaire before colonoscopy. This data was entered into the NHS BCS pilot database, data from the English arm has been analysed retrospectively. RESULTS: There were 200 patients diagnosed with colorectal cancer. Of these, 28.5% were Dukes A, 35% Dukes B, 31% Dukes C1 and 5.5% Dukes C2. Some 81.5% reported experiencing GI symptoms. Symptoms considered significant included rectal bleeding, change in bowel habit, tenesmus and peri-anal discomfort, reported in 47.7%, 24%%, 36.5% and 15.5% of patients respectively. In addition to this, 27% reported urgency, 20.5% reported abdominal pain and 29% reported upper GI symptoms. DISCUSSION: This data suggests a high prevalence of significant symptoms amongst patients with screening-detected CRC. It is possible that these patients would have presented via routine colorectal services if the awareness of symptoms of colorectal cancer were increased.


Asunto(s)
Neoplasias Colorrectales/diagnóstico , Tamizaje Masivo , Humanos , Sangre Oculta , Sensibilidad y Especificidad , Medicina Estatal , Reino Unido
9.
Prostate ; 69(9): 982-90, 2009 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-19301310

RESUMEN

BACKGROUND: Reports indicate that vascular endothelial growth factor receptor type 3 (VEGFR3) regulates cellular functions such as invasion, proliferation, and chemo-resistance. However, the exact function of the VEGFR3 signaling axis in prostate epithelial cells is poorly characterized. METHODS: The goal of this study was to evaluate whether TGFbeta1 in combination with VEGFD can promote pre-malignant invasive activities of intermediate basal cells (IBC-10a) isolated from human prostate cancer (Gleason score 6). RESULTS: hTERT immortalized IBC-10a cells normally grew as confluent "cobblestoned" monolayers, but treatment with TGFbeta1 (10 ng/ml for 2-6 hr) dissociated the cell-cell junctions and induced VEGFR3 translocation to the cell surface. This event was not inhibited by 10 microM cycloheximide or puromycin, indicating transcription and protein synthesis were not required. We further discovered that TGFbeta1 in combination with VEGFD induced a significant increase in the invasive activity of IBC-10a cells (>26% and 53% after 24 and 48 hr, respectively) in modified Boyden Chamber assays. TGFbetaRII receptor antibodies specifically blocked TGFbeta1 induction of VEGFR3 translocation to the cell surface and blocked VEGFD-induced invasion. Zymograms revealed that TGFbeta1 (and not VEGFR3) stimulated the secretion of MMP-2 and MMP-9, presumably to promote cell invasion. The cell invasion assays confirmed that antibodies specific for TGFbetaII receptor, MMP-2 and MMP-9 and VEGFR3, independently blocked TGFbeta1-induced invasion. CONCLUSIONS: For the first time, we have demonstrated the mechanism by which TGFbeta1 stimulates VEGFD/VEGFR3 receptor axis activation leading to increased cell migration and invasion by primary intermediate basal cell cultures.


Asunto(s)
Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Factor de Crecimiento Transformador beta1/metabolismo , Factor D de Crecimiento Endotelial Vascular/metabolismo , Receptor 3 de Factores de Crecimiento Endotelial Vascular/metabolismo , Línea Celular Transformada , Quimiotaxis/efectos de los fármacos , Quimiotaxis/fisiología , Humanos , Uniones Intercelulares/metabolismo , Masculino , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 9 de la Matriz/metabolismo , Próstata/metabolismo , Próstata/patología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Factor de Crecimiento Transformador beta1/farmacología , Células Tumorales Cultivadas , Factor D de Crecimiento Endotelial Vascular/farmacología
10.
Prostate ; 69(7): 689-98, 2009 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-19143028

RESUMEN

BACKGROUND: The CD133(hi) sub-population of prostate epithelial cells has been demonstrated to possess tumor-initiating capacity consistent with that of the cancer stem cell theory. However, the involvement of oncogenes such as c-myc has not been fully elucidated in the CD133(hi) sub-population. METHODS: We have isolated primary prostate cell strains (IBC-10a) and immortalized them by transfection with hTERT. The in vitro and in vivo tumorigenic capacity of isolated CD133(hi) and CD133(lo) cells was evaluated with respect to c-myc expression using specific sense and anti-sense oligonucleotides. RESULTS: Freshly immortalized cells consisted of <3.3% CD133(hi)/CD24(hi) sub-population (SP). "Prostaspheres" generated from single CD133(hi) cells in the presence of EGF consisted of approximately 10% CD133(hi) SPs in 12-21 day cultures. A single Prostasphere generated from single CD133(hi) cells (6-10 cell stage at day 6 injected i.t.) produced dysplastic lesions in NOD-SCID mice (n = 4/5). Treatment of Prostaspheres from CD133(hi) SPs in vitro with c-myc or cyclin D1 anti-sense oligonucleotides totally blocked colony forming ability and growth. Furthermore, treatment of fully formed, 6-day Prostaspheres for 48 hr with c-myc anti-sense significantly reduced c-myc expression and their ability to generate lesions in NOD-SCIDs (n = 10 Prostaspheres injected i.t./mouse). CONCLUSIONS: These data demonstrate for the first time that a single CD133(hi) cell is competent to generate Prostaspheres in vitro and that CD133(hi) Prostaspheres require c-myc to grow and form dysplastic lesions in vivo.


Asunto(s)
Antígenos CD/biosíntesis , ADN sin Sentido/genética , Glicoproteínas/biosíntesis , Células Madre Neoplásicas/patología , Neoplasias de la Próstata/patología , Proteínas Proto-Oncogénicas c-myc/genética , Antígeno AC133 , Animales , Western Blotting , ADN sin Sentido/administración & dosificación , Citometría de Flujo , Humanos , Cariotipificación , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Persona de Mediana Edad , Péptidos , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/inmunología , Proteínas Proto-Oncogénicas c-myc/biosíntesis , Telomerasa/genética , Transfección
11.
Aliment Pharmacol Ther ; 29(1): 83-9, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18793341

RESUMEN

BACKGROUND: Ghrelin, a potent orexigenic peptide produced by the stomach, may be affected by circulating inflammatory mediators. AIM: To assess the effect of an anti-TNFα antibody on ghrelin in patients with Crohn's disease (CD). METHODS: Fifteen patients with Crohn's receiving infliximab were studied before and 1 week after infusion. Following an overnight fast, blood was sampled before a meal and then every 20 min for 2 h. Total ghrelin and CRP were measured using ELISA. Acylated ghrelin and TNFα, IFNγ, IL-1ß and IL-6 were measured with bioplex. Harvey Bradshaw Activity Index was assessed. RESULTS: Median (95% CI) 2-h integrated plasma total ghrelin increased from 162 (99-311) before infliximab to 200 (128-387) pg/mL h, (P = 0.02) after. Following infliximab, 20 min postmeal, median acylated ghrelin decreased from 50.3 (24-64) to 38.6 (26-82) pg/mL, (P = 0.04) thus reverting to a traditional meal related ghrelin curve. Median (range) disease activity decreased from 5 (2-28) before to 3 (0-22), (P = 0.0001) and Median (95% CI) TNFα decreased from 2.8 (1.89-4.48) to 1.31 (0.73-2.06) pg/mL (P = 0.002). CONCLUSIONS: Infliximab increases circulating total ghrelin by 25% in CD and restores the postprandial response of acylated ghrelin to food intake. Acylated and de-sacyl ghrelin remain unchanged, suggesting that an alternate isoform could be affected by infliximab.


Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Enfermedad de Crohn/tratamiento farmacológico , Fármacos Gastrointestinales/uso terapéutico , Ghrelina/sangre , Mediadores de Inflamación/uso terapéutico , Factor de Necrosis Tumoral alfa/uso terapéutico , Adulto , Anticuerpos Monoclonales/sangre , Enfermedad de Crohn/sangre , Ensayo de Inmunoadsorción Enzimática , Femenino , Fármacos Gastrointestinales/sangre , Humanos , Mediadores de Inflamación/sangre , Infliximab , Masculino , Persona de Mediana Edad , Factor de Necrosis Tumoral alfa/sangre , Adulto Joven
12.
Br J Surg ; 95(9): 1172-9, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18690636

RESUMEN

BACKGROUND: The English arm of the UK Bowel Cancer Screening Pilot study recently concluded its third round. The primary aim was to assess the impact of faecal occult blood test (FOBT) screening on the detection of symptomatic (non-screen-detected) cancers within the target age group (50-69 years). The secondary aim was to assess differences between screened and non-screened cohorts in Dukes' classification at diagnosis. METHODS: This population-based study utilized retrospective analysis of existing validated colorectal cancer (CRC) data over 5 years (April 2000 to March 2005), encompassing rounds one and two of screening. RESULTS: There was a 23 per cent (P = 0.011) reduction in the diagnosis of over the 5 years. Presentations with symptomatic cancer reduced by 49 per cent (P = 0.049), with a proportionate (2.6-fold) rise in the detection of screened (asymptomatic) malignancy. Cancers were diagnosed at an earlier stage in the screened population, with significantly more Dukes' A tumours than in the non-screen-detected cohort (P < 0.001) and an estimated odds ratio of 0.27 (95 per cent confidence interval 0.08 to 0.91) (P = 0.035) for Dukes' 'D' cancers. CONCLUSION: FOBT screening resulted in a significant reduction in the number of symptomatic cancers detected within the target age group. Tumours detected by screening were diagnosed at an earlier pathological stage.


Asunto(s)
Neoplasias Colorrectales/epidemiología , Tamizaje Masivo/métodos , Sangre Oculta , Anciano , Neoplasias Colorrectales/patología , Inglaterra/epidemiología , Métodos Epidemiológicos , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad
13.
Gut ; 57(2): 218-22, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18048571

RESUMEN

OBJECTIVE: The English arm of the UK Bowel Cancer Screening Pilot has recently concluded its third round. The primary aim of this study was to assess the effects of this programme on the emergency and elective cancer workload at University Hospitals Coventry and Warwickshire NHS Trust; the largest trust within the screened region. The secondary aim was to assess its effect upon Dukes staging, mortality and stoma formation for emergency colorectal cancer (CRC) admissions. DESIGN: A retrospective analysis of validated data for CRC admissions over a period of 6 years from 1999 to 2004 was performed. The first year, 1999, represented the pre-screening year (PSY) which was taken as a baseline. Data for the next 5 years, screening years 1-5 (SY1-SY5), were recorded for the mode of admission, occurrence of emergency surgery, 30-day mortality and Dukes staging. RESULTS: In the PSY (1999), 29.4% of CRCs were admitted as an emergency, decreasing to 15.8% by 2004 (p = 0.001). As a consequence, there was a significant decrease in the number of emergency CRC procedures performed over the same period (p<0.05). There was also a significant reduction in the 30-day mortality from 48% in 1999 to 13% in 2004 (p<0.05). Dukes stage C carcinomas, however, remained the predominant stage presenting as emergencies throughout the studied period (SY3, 53%; SY4, 38%; SY5, 50%). CONCLUSION: Following commencement of the UK Bowel Cancer Screening Pilot, there has been a significant decline in emergency CRC workload with a marked improvement in 30-day mortality and decreased stoma formation, in Coventry and North Warwickshire. It is postulated that the witnessed and notable positive impact over such a short time period is the result of increased detection of asymptomatic malignancies within the screening programme, increased public awareness of the symptoms of CRC, together with a change in attitudes and referral patterns of general practitioners within Coventry and North Warwickshire.


Asunto(s)
Neoplasias Colorrectales/prevención & control , Procedimientos Quirúrgicos Electivos/estadística & datos numéricos , Servicios Médicos de Urgencia/estadística & datos numéricos , Tamizaje Masivo/estadística & datos numéricos , Sangre Oculta , Anciano , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/cirugía , Colostomía/estadística & datos numéricos , Urgencias Médicas , Inglaterra , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias/métodos , Proyectos Piloto
15.
Environ Pollut ; 51(4): 315-26, 1988.
Artículo en Inglés | MEDLINE | ID: mdl-15092623

RESUMEN

In the ambient environment, concentrations of air pollutants vary on a diurnal cycle, resulting in various patterns of concurrent and sequential exposures of plants. The response of tomato plants to sequential and concurrent NO2 and O3 exposures was determined using pollutant levels equal to the maximum acceptable levels recommended by the National Ambient Air Quality Objectives of Environment Canada for a 1 h average. The concurrent treatment, 1 h of NO2 + O3, was compared to 1 h of NO20, O3 or control in plants at the 4 to 6 or the 9 to 11 leaf stage. At the 4 to 6 leaf stage, leaf and stem fresh weights were significantly reduced by the NO2 + O3 treatment relative to control, whereas these growth parameters were not reduced relative to control by the single pollutants indicating a coalitive response. Leaf area was significantly smaller as a result of the NO2 + O3 treatment relative to the NO2 treatment. A main effect of O3 was observed on leaf dry weight. The sequential treatments were: NO2 followed by O3 (NO2-O3); O3 followed by NO2 (O3-NO2); NO2 at night followed by O3 during the daytime (NO2(N)-O3(D)). Each gas exposure was 1 h; only plants at the 4 to 6 leaf stage were treated. Only the O3-NO2 treatment significantly reduced leaf area, leaf fresh weight and stem fresh and dry weights relative to control plants. Inconsistencies among treatments occurring at different time periods of the day suggest that time period of exposure should reflect ambient time periods. The coalitive action, and the sequential treatment response, of these pollutants indicated that criteria based on single pollutants may not be adequate to establish air quality objectives when these pollutants occur together.

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