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1.
Br J Cancer ; 129(7): 1142-1151, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37596405

RESUMEN

BACKGROUND: The TNM system is used to assess prognosis after colorectal cancer (CRC) diagnosis. Other prognostic factors reported include histopathological assessments of the tumour, tumour mutations and proteins in the blood. As some of these factors are strongly correlated, it is important to evaluate the independent effects they may have on survival. METHODS: Tumour samples from 2162 CRC patients were visually assessed for amount of tumour stroma, severity of lymphocytic infiltrate at the tumour margins and the presence of lymphoid follicles. Somatic mutations in the tumour were assessed for 2134 individuals. Pre-surgical levels of 4963 plasma proteins were measured in 128 individuals. The associations between these features and prognosis were inspected by a Cox Proportional Hazards Model (CPH). RESULTS: Levels of stroma, lymphocytic infiltration and presence of lymphoid follicles all associate with prognosis, along with high tumour mutation burden, high microsatellite instability and TP53 and BRAF mutations. The somatic mutations are correlated with the histopathology and none of the somatic mutations associate with survival in a multivariate analysis. Amount of stroma and lymphocytic infiltration associate with local invasion of tumours. Elevated levels of two plasma proteins, CA-125 and PPP1R1A, associate with a worse prognosis. CONCLUSIONS: Tumour stroma and lymphocytic infiltration variables are strongly associated with prognosis of CRC and capture the prognostic effects of tumour mutation status. CA-125 and PPP1R1A may be useful prognostic biomarkers in CRC.


Asunto(s)
Neoplasias Colorrectales , Humanos , Neoplasias Colorrectales/diagnóstico , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Pronóstico , Modelos de Riesgos Proporcionales , Inestabilidad de Microsatélites , Proteínas Proto-Oncogénicas B-raf/genética , Mutación
2.
Conserv Biol ; 33(2): 456-468, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30465331

RESUMEN

Although evidence-based approaches have become commonplace for determining the success of conservation measures for the management of threatened taxa, there are no standard metrics for assessing progress in research or management. We developed 5 metrics to meet this need for threatened taxa and to quantify the need for further action and effective alleviation of threats. These metrics (research need, research achievement, management need, management achievement, and percent threat reduction) can be aggregated to examine trends for an individual taxon or for threats across multiple taxa. We tested the utility of these metrics by applying them to Australian threatened birds, which appears to be the first time that progress in research and management of threats has been assessed for all threatened taxa in a faunal group at a continental scale. Some research has been conducted on nearly three-quarters of known threats to taxa, and there is a clear understanding of how to alleviate nearly half of the threats with the highest impact. Some management has been attempted on nearly half the threats. Management outcomes ranged from successful trials to complete mitigation of the threat, including for one-third of high-impact threats. Progress in both research and management tended to be greater for taxa that were monitored or occurred on oceanic islands. Predation by cats had the highest potential threat score. However, there has been some success reducing the impact of cat predation, so climate change (particularly drought), now poses the greatest threat to Australian threatened birds. Our results demonstrate the potential for the proposed metrics to encapsulate the major trends in research and management of both threats and threatened taxa and provide a basis for international comparisons of evidence-based conservation science.


Medidas de Progreso en el Entendimiento y el Manejo de las Amenazas que Enfrentan las Aves Australianas Resumen Aunque los métodos basados en evidencias se han vuelto muy comunes para la determinación del éxito de las medidas de conservación del manejo de los taxones amenazados, hoy en día no existen medidas estandarizadas para la evaluación del progreso de la investigación o el manejo. Desarrollamos cinco medidas para cumplir con esta necesidad que tienen los taxones amenazados y para cuantificar la necesidad de una mayor acción y un alivio efectivo de las amenazas. Estas medidas (falta de investigación, éxito de la investigación, falta de manejo, éxito del manejo y porcentaje de reducción de amenazas) pueden agregarse para examinar las tendencias de un taxón individual o las tendencias de las amenazas para múltiples taxones. Probamos la utilidad de estas medidas por medio de su aplicación en aves australianas amenazadas, que parece ser la primera vez que se evalúa el progreso en la investigación y en el manejo de amenazas para el caso de varios taxones amenazados dentro de un grupo faunístico a escala continental. Se ha realizado algún tipo de investigación sobre casi tres cuartas partes de las amenazas conocidas para los taxones, y hay un claro entendimiento de cómo aliviar casi la mitad de las amenazas con el impacto más alto. Se ha intentado algún tipo de manejo con casi la mitad de las amenazas. Los resultados del manejo variaron desde ensayos exitosos hasta la mitigación completa de la amenaza, incluso para un tercio de las amenazas de alto impacto. Tanto el progreso en la investigación como en el manejo tendió a ser mayor para los taxones que estaban siendo monitoreados, o que ocurrían en islas oceánicas. La depredación por gatos tuvo el puntaje más como amenaza potencial. Sin embargo, ha habido poco de éxito en la reducción del impacto de la depredación por gatos, así que ahora el cambio climático (particularmente la sequía) es la mayor amenaza para las aves amenazadas en Australia. Nuestros resultados demuestran el potencial que tienen las medidas propuestas de encapsular las tendencias más importantes en la investigación y en el manejo tanto de las amenazas como de los taxones amenazados y de proporcionar una base para comparaciones internacionales de la ciencia de la conservación basada en evidencias.


Asunto(s)
Conservación de los Recursos Naturales , Especies en Peligro de Extinción , Animales , Australia , Biodiversidad , Aves , Gatos , Islas
3.
J Environ Qual ; 42(5): 1460-5, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24216423

RESUMEN

The antibiotic lincomycin is commonly found in treated municipal waste water and in waste from swine and poultry production. Environmental disposal of these wastes has the potential to introduce a significant mass of lincomycin into the ecosystem. In the present study, a series of sorption and desorption experiments were conducted to determine the potential mobility of lincomycin in soils from arid environments. Sorption and desorption isotherms were obtained for lincomycin using three different soils. Isotherms were fit to the Freundlich equation. Adsorption of lincomycin was found to have a of 11.98 for a biosolid-treated soil (1.58% OC) and a of 210.15 for a similar unamended soil (1.42% OC). It was also found that for a low-organic-content soil the was 5.09. The differences in adsorption can be related to the soil pH and the pKa of lincomycin (7.5-7.8). When the soil solution pH is below the pKa, the cationic species of lincomycin dominates, resulting in increased water solubility. Interaction with the cation exchange complex is minimal due to a high solution cation concentration (Ca and Na). Desorption isotherms also indicate that when the solution pH is lower than the pKa, retention of lincomycin is reduced. Our results indicate that the mobility of lincomycin in these arid region soils is dependent on soil pH.


Asunto(s)
Lincomicina , Suelo , Adsorción , Contaminantes del Suelo/química
4.
J Exp Med ; 220(6)2023 06 05.
Artículo en Inglés | MEDLINE | ID: mdl-36995340

RESUMEN

Phagocytosis is a key macrophage function, but how phagocytosis shapes tumor-associated macrophage (TAM) phenotypes and heterogeneity in solid tumors remains unclear. Here, we utilized both syngeneic and novel autochthonous lung tumor models in which neoplastic cells express the fluorophore tdTomato (tdTom) to identify TAMs that have phagocytosed neoplastic cells in vivo. Phagocytic tdTompos TAMs upregulated antigen presentation and anti-inflammatory proteins, but downregulated classic proinflammatory effectors compared to tdTomneg TAMs. Single-cell transcriptomic profiling identified TAM subset-specific and common gene expression changes associated with phagocytosis. We uncover a phagocytic signature that is predominated by oxidative phosphorylation (OXPHOS), ribosomal, and metabolic genes, and this signature correlates with worse clinical outcome in human lung cancer. Expression of OXPHOS proteins, mitochondrial content, and functional utilization of OXPHOS were increased in tdTompos TAMs. tdTompos tumor dendritic cells also display similar metabolic changes. Our identification of phagocytic TAMs as a distinct myeloid cell state links phagocytosis of neoplastic cells in vivo with OXPHOS and tumor-promoting phenotypes.


Asunto(s)
Neoplasias Pulmonares , Macrófagos , Humanos , Macrófagos/metabolismo , Fagocitosis/genética , Neoplasias Pulmonares/patología , Células Mieloides/metabolismo , Estrés Oxidativo , Microambiente Tumoral
5.
Nat Commun ; 11(1): 5978, 2020 12 08.
Artículo en Inglés | MEDLINE | ID: mdl-33293507

RESUMEN

Many global environmental agendas, including halting biodiversity loss, reversing land degradation, and limiting climate change, depend upon retaining forests with high ecological integrity, yet the scale and degree of forest modification remain poorly quantified and mapped. By integrating data on observed and inferred human pressures and an index of lost connectivity, we generate a globally consistent, continuous index of forest condition as determined by the degree of anthropogenic modification. Globally, only 17.4 million km2 of forest (40.5%) has high landscape-level integrity (mostly found in Canada, Russia, the Amazon, Central Africa, and New Guinea) and only 27% of this area is found in nationally designated protected areas. Of the forest inside protected areas, only 56% has high landscape-level integrity. Ambitious policies that prioritize the retention of forest integrity, especially in the most intact areas, are now urgently needed alongside current efforts aimed at halting deforestation and restoring the integrity of forests globally.


Asunto(s)
Biodiversidad , Conservación de los Recursos Naturales/estadística & datos numéricos , Política Ambiental , Bosques , África Central , Canadá , Cambio Climático , Conservación de los Recursos Naturales/legislación & jurisprudencia , Nueva Guinea , Federación de Rusia
6.
Diabetologia ; 52(5): 901-11, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19252893

RESUMEN

AIMS/HYPOTHESIS: Insulin stimulates phosphorylation cascades, including phosphatidylinositol-3-kinase (PI3K), phosphatidylinositol-dependent kinase (PDK1), Akt, and protein kinase C (PKC). Myristoylated alanine-rich C-kinase substrate (MARCKS), a PKCbetaII substrate, could link the effects of insulin to insulin-stimulated glucose transport (ISGT) via phosphorylation of its effector domain since MARCKS has a role in cytoskeletal rearrangements. METHODS: We examined phosphoPKCbetaII after insulin treatment of L6 myocytes, and cytosolic and membrane phosphoMARCKS, MARCKS and phospholipase D1 in cells pretreated with LY294002 (PI3K inhibitor), CG53353 (PKCbetaII inhibitor) or W13 (calmodulin inhibitor), PI3K, PKCbetaII and calmodulin inhibitors, respectively, before insulin treatment, using western blots. ISGT was examined after cells had been treated with inhibitors, small inhibitory RNA (siRNA) for MARCKS, or transfection with MARCKS mutated at a PKC site. MARCKS, PKCbetaII, GLUT4 and insulin receptor were immunoblotted in subcellular fractions with F-actin antibody immunoprecipitates to demonstrate changes following insulin treatment. GLUT4 membrane insertion was followed after insulin with or without CG53353. RESULTS: Insulin increased phosphoPKCbetaII(Ser660 and Thr641); LY294002 blocked this, indicating its activation by PI3K. Insulin treatment increased cytosolic phosphoMARCKS, decreased membrane MARCKS and increased membrane phospholipase D1 (PLD1), a protein regulating glucose transporter vesicle fusion resulted. PhosphoMARCKS was attenuated by CG53353 or MARCKS siRNA. MARCKS siRNA blocked ISGT. Association of PKCbetaII and GLUT4 with membrane F-actin was enhanced by insulin, as was that of cytosolic and membrane MARCKS. ISGT was attenuated in myocytes transfected with mutated MARCKS (Ser152Ala), whereas overproduction of wild-type MARCKS enhanced ISGT. CG53353 blocked insertion of GLUT4 into membranes of insulin treated cells. CONCLUSIONS/INTERPRETATION: The results suggest that PKCbetaII is involved in mediating downstream steps of ISGT through MARCKS phosphorylation and cytoskeletal remodelling.


Asunto(s)
Glucosa/metabolismo , Insulina/farmacología , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas de la Membrana/metabolismo , Músculo Esquelético/metabolismo , Proteína Quinasa C/metabolismo , Animales , Diferenciación Celular , Cromonas/farmacología , ADN Complementario/genética , Desoxiglucosa/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética , Proteínas de la Membrana/genética , Morfolinas/farmacología , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/enzimología , Mioblastos/citología , Mioblastos/efectos de los fármacos , Mioblastos/enzimología , Mioblastos/metabolismo , Sustrato de la Proteína Quinasa C Rico en Alanina Miristoilada , Fosfoserina/metabolismo , Fosfotreonina/metabolismo , Proteína Quinasa C/genética , Proteína Quinasa C beta , ARN Interferente Pequeño/genética , Ratas
7.
Science ; 189(4200): 381-2, 1975 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-1170639

RESUMEN

Magadina cumingi inhabits an environment of high current energy and mobile sediments by using its pedicle in Pogo-stick fashion as an elevating device. This type of progression is associated with pedicle musculature different from that of attached and other free-lying forms, and some diagnostic differences in muscle attachment areas are evident in preservable hard parts.


Asunto(s)
Invertebrados/fisiología , Locomoción , Animales , Invertebrados/anatomía & histología , Músculos/fisiología
8.
Conserv Biol ; 23(4): 834-40, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19627315

RESUMEN

Oceania is a diverse region encompassing Australia, Melanesia, Micronesia, New Zealand, and Polynesia, and it contains six of the world's 39 hotspots of diversity. It has a poor record for extinctions, particularly for birds on islands and mammals. Major causes include habitat loss and degradation, invasive species, and overexploitation. We identified six major threatening processes (habitat loss and degradation, invasive species, climate change, overexploitation, pollution, and disease) based on a comprehensive review of the literature and for each developed a set of conservation policies. Many policies reflect the urgent need to deal with the effects of burgeoning human populations (expected to increase significantly in the region) on biodiversity. There is considerable difference in resources for conservation, including people and available scientific information, which are heavily biased toward more developed countries in Oceania. Most scientific publications analyzed for four threats (habitat loss, invasive species, overexploitation, and pollution) are from developed countries: 88.6% of Web of Science publications were from Australia (53.7%), New Zealand (24.3%), and Hawaiian Islands (10.5%). Many island states have limited resources or expertise. Even countries that do (e.g., Australia, New Zealand) have ongoing and emerging significant challenges, particularly with the interactive effects of climate change. Oceania will require the implementation of effective policies for conservation if the region's poor record on extinctions is not to continue.


Asunto(s)
Biodiversidad , Conservación de los Recursos Naturales , Ambiente , Animales , Contaminación Ambiental , Humanos , Oceanía
9.
Oncogene ; 25(49): 6544-53, 2006 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-16702952

RESUMEN

We analysed chromosome 16q in 106 breast cancers using tiling-path array-comparative genomic hybridization (aCGH). About 80% of ductal cancers (IDCs) and all lobular cancers (ILCs) lost at least part of 16q. Grade I (GI) IDCs and ILCs often lost the whole chromosome arm. Grade II (GII) and grade III (GIII) IDCs showed less frequent whole-arm loss, but often had complex changes, typically small regions of gain together with larger regions of loss. The boundaries of gains/losses tended to cluster, common sites being 54.5-55.5 Mb and 57.4-58.8 Mb. Overall, the peak frequency of loss (83% cancers) occurred at 61.9-62.9 Mb. We also found several 'minimal' regions of loss/gain. However, no mutations in candidate genes (TRADD, CDH5, CDH8 and CDH11) were detected. Cluster analysis based on copy number changes identified a large group of cancers that had lost most of 16q, and two smaller groups (one with few changes, one with a tendency to show copy number gain). Although all morphological types occurred in each cluster group, IDCs (especially GII/GIII) were relatively overrepresented in the smaller groups. Cluster groups were not independently associated with survival. Use of tiling-path aCGH prompted re-evaluation of the hypothetical pathways of breast carcinogenesis. ILCs have the simplest changes on 16q and probably diverge from the IDC lineage close to the stage of 16q loss. Higher-grade IDCs probably develop from low-grade lesions in most cases, but there remains evidence that some GII/GIII IDCs arise without a GI precursor.


Asunto(s)
Neoplasias de la Mama/genética , Carcinoma Ductal de Mama/genética , Carcinoma Lobular/genética , Cromosomas Humanos Par 16 , Invasividad Neoplásica/genética , Hibridación de Ácido Nucleico/métodos , Análisis de Matrices Tisulares/métodos , Aberraciones Cromosómicas , Rotura Cromosómica , Análisis por Conglomerados , ADN de Neoplasias , Amplificación de Genes , Eliminación de Gen , Ligamiento Genético , Humanos , Pérdida de Heterocigocidad , Modelos Estadísticos , Estadificación de Neoplasias
10.
Cancer Res ; 60(6): 1690-7, 2000 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-10749141

RESUMEN

We have identified a >600-kb region at 16q23.2 that is homozygously deleted from malignant ovarian ascites using representational difference analysis. Overlapping homozygous deletions were also observed in the colon carcinoma cell line HCT116 and a xenograft established from the small cell lung cancer cell line WX330. This region coincides with that described previously by others as showing loss of heterozygosity in prostate and breast cancers (C. Li et al., Genes Chromosomes Cancer, 24: 175-182, 1999; A. Latil et al., Cancer Res., 57: 1058-1062, 1997; K. Driouch et al., Genes Chromosomes Cancer, 19: 185-191, 1997; A. Iida et al., Br. J. Cancer, 75: 264-267, 1997). In addition, the minimally deleted region spans the common fragile site FRA16D. We have constructed a 700-kb physical map encompassing the deleted region. By fluorescence in situ hybridization of aphidicolin-induced metaphase chromosomes, we have preliminary data to suggest that P1-derived bacterial artificial chromosome clones from the contig lie on both sides of FRA16D. This is confirmed by extensive fluorescence in situ hybridization analysis of the region reported in the accompanying article (M. Mangelsdorf et al., Cancer Res., 60: 1683-1689, 2000) and is consistent with an involvement of this common fragile site in the loss of 16q23.2 material in various cancer types. The minimally deleted region of approximately 210 kb has been characterized using our own markers and public domain markers. Eleven distinct expressed sequences mapped to the region, providing a basis for identifying the predicted tumor suppressor gene in this region.


Asunto(s)
Deleción Cromosómica , Fragilidad Cromosómica , Cromosomas Humanos Par 16/genética , Neoplasias/genética , Bacteriófago P1 , Bandeo Cromosómico , Sitios Frágiles del Cromosoma , Cromosomas Artificiales de Levadura , Clonación Molecular , Mapeo Contig , ADN de Neoplasias/genética , Predisposición Genética a la Enfermedad/genética , Homocigoto , Humanos , Hibridación Fluorescente in Situ , Mapeo Físico de Cromosoma , Células Tumorales Cultivadas
11.
Cancer Res ; 59(12): 2806-9, 1999 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-10383136

RESUMEN

Loss of heterozygosity (LOH) at 11q23-qter occurs frequently in ovarian and other cancers, but for colorectal cancer, the evidence is conflicting. Seven polymorphic loci were analyzed between D11S897 and D11S969 in 50 colorectal tumors. Two distinct LOH regions were detected, suggesting possible sites for tumor-suppressor genes involved in colorectal neoplasia: a large centromeric region between D11S897 and D11S925, and a telomeric 4.9-Mb region between D11S912 and D11S969. There was no correlation with clinicopathological features. This analysis describes a region of LOH in the region 11q23.3-24.3 for the first time in colorectal cancer and provides complementary evidence for the ongoing effort to identify the gene(s) involved.


Asunto(s)
Cromosomas Humanos Par 11 , Neoplasias Colorrectales/genética , Pérdida de Heterocigocidad , Anciano , Cartilla de ADN , Femenino , Humanos , Masculino
12.
Cancer Res ; 56(5): 950-4, 1996 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-8640783

RESUMEN

Previous cytogenetic and loss of heterozygosity (LOH) data suggest that disruption of chromosome 11q23-qter occurs frequently in epithelial ovarian cancer and is associated with an adverse clinicopathological phenotype. Ten polymorphic microsatellite repeat loci were analyzed by PCR from the 11q22-q25 region between D11S35 and D11S968 in 40 ovarian tumors (including 31 epithelial ovarian cancers). Two distinct regions of loss were detected, suggesting possible sites for genes involved in epithelial ovarian neoplasia: a large centromeric region between D11S35 and D11S933 (11q22-q23.3) and a telomeric 8.5-Mb region lying between D11S934 and D11S1320 (11q23.3-24.3) not previously defined. LOH of the latter region but not the former one was significantly associated with poor survival, despite all tumors in this study having LOH somewhere on chromosome 11. This analysis provides a starting point for positional cloning.


Asunto(s)
Carcinoma/genética , Cromosomas Humanos Par 11 , Neoplasias Ováricas/genética , Carcinoma/fisiopatología , Mapeo Cromosómico , Femenino , Heterocigoto , Humanos , Neoplasias Ováricas/fisiopatología , Análisis de Supervivencia
14.
Oncogene ; 7(4): 763-8, 1992 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1314370

RESUMEN

A candidate gene (WT1) has recently been described for the 11p13 tumour-suppressor gene involved in the development of Wilms' tumour. This gene encodes a zinc finger protein which can bind to a specific DNA sequence. We have found a 226 base deletion in the mRNA from a unilateral Wilms' tumour, which would cause a frameshift that completely deletes the zinc finger domain. The tumour developed in a patient suffering from the WAGR syndrome, who had a constitutional 11p13 deletion, and so the 226 base deletion represents the inactivation of the remaining WT1 allele in the tumour. This provides further direct evidence that loss of function of WT1 is an essential step in the development of Wilms' tumour.


Asunto(s)
Anomalías Múltiples/genética , Aniridia/genética , Proteínas de Unión al ADN/genética , Anomalías Urogenitales , Tumor de Wilms/genética , Secuencia de Aminoácidos , Secuencia de Bases , Southern Blotting , Deleción Cromosómica , Cromosomas Humanos Par 11 , ADN de Neoplasias/genética , Genes Supresores de Tumor , Humanos , Datos de Secuencia Molecular , Oligodesoxirribonucleótidos/química , Reacción en Cadena de la Polimerasa , ARN Neoplásico/genética , Síndrome , Proteínas WT1 , Dedos de Zinc
15.
Oncogene ; 23(19): 3487-94, 2004 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-15007382

RESUMEN

We have constructed a high-resolution genomic microarray of human chromosome 16q, and used it for comparative genomic hybridization analysis of 16 prostate tumors. We demarcated 10 regions of genomic loss between 16q23.1 and 16qter that occurred in five or more samples. Mining expression array data from four independent studies allowed us to identify 11 genes that were frequently underexpressed in prostate cancer and that co-localized with a region of genomic loss. Quantitative expression analyses of these genes in matched tumor and benign tissue from 13 patients showed that six of these 11 (WWOX, WFDC1, MAF, FOXF1, MVD and the predicted novel transcript Q9H0B8 (NM_031476)) had significant and consistent downregulation in the tumors relative to normal prostate tissue expression making them candidate tumor suppressor genes.


Asunto(s)
Cromosomas Humanos Par 16 , Genes Supresores de Tumor , Hibridación de Ácido Nucleico , Neoplasias de la Próstata/genética , Humanos , Masculino
16.
Biochim Biophys Acta ; 497(1): 241-52, 1977 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-849481

RESUMEN

The uptake of an injected dose of [3H]folic acid and its metabolism to pteroylpoly-gamma-glutamate forms by the livers and kidneys of vitamin B-12- and methionine-deficient and -supplemented rats were investigated. The initial hepatic uptake of the labeled folate dose was the same in deficient and supplemented animals, demonstrating no involvement of vitamin B-12 or methionine in folate transport. At longer time periods, a decreased hepatic net uptake of labeled folate was observed in the deficient animals compared to supplemented animals, and this was directly correlated with the decreased ability of the deficient animals to synthesize pteroylpolyglutamates. The absolute rate of loss of labeled pteroylmonoglutamate from liver was the same in deficient and supplemented animals. These data are best explained by a modification of the 'methyl trap' hypothesis for the interrelationship of vitamin B-12 and folate metabolism. Vitamin B-12 deficiency can lead to lowered levels of 5-methyltetrahydrofolate:homocysteine methyltransferase, creating a functional folate deficiency by 'trapping' an increased proportion of folate as the methyl derivative. In addition, as methyltetrahydrofolate is a poor substrate for folylpoly-gamma-glutamate synthetase, there is a decreased synthesis of pteroylpolyglutamates, the forms of the vitamin that are preferentially retained by tissues. This results in decreased tissue folate levels under conditions of vitamin B-12 deficiency. Vitamin B-12 and methionine deficiency had no significant effect on the distribution of endogenous pteroylpolyglutamates in rat liver and kidney, although total endogenous folate in rat liver was reduced by about 60%. The distribution of labeled pteroylpolyglutamates in rat liver and kidney 48 h after the tracer dose of [3H]folate closely resembled the endogenous distribution in these tissues.


Asunto(s)
Ácido Fólico/análogos & derivados , Ácido Fólico/metabolismo , Metionina/deficiencia , Deficiencia de Vitamina B 12/metabolismo , Animales , Riñón/metabolismo , Hígado/metabolismo , Masculino , Metionina/uso terapéutico , Ratas , Vitamina B 12/uso terapéutico , Deficiencia de Vitamina B 12/tratamiento farmacológico
17.
Biochim Biophys Acta ; 497(1): 234-40, 1977 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-849480

RESUMEN

A simplified procedure for the determination of the glutamate chain lengths of endogenous tissue folate is described. Natural pteroylpoly-gamma-glutamates in tissue extracts, irrespective of their one-carbon moiety, were converted by a reductive cleavage procedure to a homologous series of p-aminobenzoylpoly-gamma-glutamates, differing only in glutamate chain length. Desalting and concentration of the extracts were achieved by absorbing the derivatives on active charcoal followed by their elution with ethanol:ammonia. Aminobenzoylpolyglutamates were separated by DEAD-cellulose chromatography and quantitated by a colorimetric procedure for primary aromatic amines. The major endogenous folates in rat liver and kidney were pteroylpentaglutamate derivatives with smaller amounts of pteroyltetra- and hexaglutamate.


Asunto(s)
Ácido Fólico/análogos & derivados , Glutamatos/análisis , Animales , Fenómenos Químicos , Química , Riñón/análisis , Hígado/análisis , Masculino , Ratas
18.
Biochim Biophys Acta ; 1054(1): 95-102, 1990 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-2200530

RESUMEN

In BC3H-1 myocytes, insulin has been reported to (a) increase diacyglycerol (DAG) production and provoke increases in protein kinase C enzyme activity of crude or DEAE-Sephacel-purified cytosol and membrane fractions in BC3H-1 myocytes (Cooper et al. (1987) J. Biol. Chem. 262, 3633-3739), but (b) decrease cytosolic, and transiently increase membrane, immunoreactive protein kinase C (Acevedo-Duncan et al. (1989) FEBS Lett. 244, 174-176). Presently, we used a Mono-Q column to purify protein kinase C and found that, similar to immunoblot findings, enzyme activity decreased in the cytosol, and increased in the membrane during insulin treatment. Similar differences in protein kinase C activation patterns were observed in rat adipose tissue: insulin stimulated cytosolic protein kinase C enzyme activity as measured after DEAE-Sephacel chromatography, but decreased cytosolic enzyme activity when measured after Mono-Q chromatography or by immunoblotting. We presently evaluated the possibility that insulin-induced increases in endogenous DAG may influence protein kinase C during assay in vitro. Crude cytosol from BC3H-1 myocytes contained 25-35% of total and [3H]glycerol-labelled DAG and insulin increased this DAG. Considerable amounts of [3H]glycerol-labelled DAG were present in insulin-stimulated protein kinase C-containing column fractions following DEAE-Sephacel chromatography of cytosol fractions, whereas lesser amounts were recovered after Mono-Q column chromatography. This difference in recovery of DAG and activation of the enzyme by this endogenous DAG may explain why we were able to discern insulin-induced (presumably translocation 'provoked') decreases in cytosolic protein kinase C in the present Mono-Q column preparations of both BC3H-1 myocytes and rat adipose tissue.


Asunto(s)
Tejido Adiposo/metabolismo , Insulina/farmacología , Músculos/metabolismo , Proteína Quinasa C/metabolismo , Animales , Línea Celular , Cromatografía/métodos , Diglicéridos/metabolismo , Activación Enzimática/efectos de los fármacos , Masculino , Fosfolípidos/metabolismo , Ratas , Fracciones Subcelulares/metabolismo
19.
Diabetes ; 39(11): 1399-407, 1990 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-2121569

RESUMEN

The extrapancreatic effects of sulfonylurea drugs include increased glucose uptake by certain peripheral tissues. To study this effect, we used BC3H1 myocytes, which are reported to respond to these drugs. Within 30 min, tolbutamide and glyburide increased [3H]-2-deoxyglucose uptake in a dose-dependent manner. The inactive analogue carboxytolbutamide had no effect on glucose transport. Because increases in glucose transport may be mediated by activation of the diacylglycerol-protein kinase C signaling system, we examined the effects of these drugs on lipid metabolism and protein kinase C activity. Unlike insulin, tolbutamide and glyburide failed to increase [3H]glycerol labeling of diacylglycerol or labeling of phospholipids by 32P. After 30 min of treatment with tolbutamide or glyburide, however, membrane-associated and cytosolic protein kinase C activity were each increased. When cells were treated with 12-O-tetradecanoylphorbol-13-acetate (TPA) for 48 h to deplete certain isoforms of protein kinase C, glyburide, tolbutamide, and acute TPA treatment failed to increase glucose uptake, suggesting that TPA and sulfonylureas operate through activation of a common pathway. The effect of glyburide was additive to TPA in stimulating glucose uptake at low but not high TPA concentrations. As with insulin and TPA, extracellular Ca2+ was not essential for sulfonylurea-stimulated glucose uptake. Staurosporine, a protein kinase C inhibitor, blocked glyburide-, tolbutamide-, and insulin-stimulated glucose uptake. In intact cells, glyburide stimulated the phosphorylation of both 80,000-Mr and 40,000-Mr proteins, which are markers for protein kinase C activation. Addition of sulfonylureas directly to the protein kinase C assay system in vitro provoked dioleinlike effects, in that sensitivity of the enzyme to Ca2+ was increased.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Diglicéridos/farmacología , Glucosa/farmacocinética , Músculos/citología , Proteína Quinasa C/metabolismo , Compuestos de Sulfonilurea/farmacología , Alcaloides/farmacología , Animales , Transporte Biológico/efectos de los fármacos , Línea Celular , Células Cultivadas , Desoxiglucosa/farmacocinética , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Gliburida/farmacología , Insulina/farmacología , Músculos/efectos de los fármacos , Músculos/enzimología , Proteína Quinasa C/antagonistas & inhibidores , Estaurosporina , Acetato de Tetradecanoilforbol/farmacología , Tolbutamida/farmacología
20.
Clin Cancer Res ; 1(9): 945-53, 1995 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9816065

RESUMEN

Forty-seven epithelial ovarian cancers were analyzed for loss of heterozygosity (LOH) at D11S35 (11q22), close to the progesterone receptor (PR) gene, and for tumoral estrogen receptor (ER) and PR content. Thirty-eight of 47 tumors were informative, and, of these, 14 exhibited LOH. There was a significant association (P = 0.014) between D11S35 LOH and low tumoral PR content. For all informative tumors, there was no correlation between ER and PR; however, exclusion of tumors with LOH from the informative series revealed a linear correlation between tumoral ER and PR (P = 0.013), and established ER (P = 0.025) and PR (P = 0.05) content as significant factors in relation to patient survival. Patients with ER-rich tumors with D11S35 LOH had particularly poor survival compared with ER-rich, D11S35 heterozygous, no loss patients (P = 0.014). Analysis of the same tumors using two other microsatellites, D11S935 (11p13) and NM23 (17q22), showed no statistically significant relationships, although there were nonsignificant trends for the correlation of ER and PR expression in informative tumors without allele loss at these loci. We propose that genomic structural alteration at or close to the PR gene locus has biological and clinical sequelae in ovarian cancer.


Asunto(s)
Cromosomas Humanos Par 11/genética , Pérdida de Heterocigocidad , Proteínas de Neoplasias/análisis , Neoplasias Ováricas/química , Neoplasias Ováricas/genética , Receptores de Progesterona/análisis , Femenino , Humanos , Técnicas para Inmunoenzimas , Repeticiones de Microsatélite , Persona de Mediana Edad , Proteínas de Neoplasias/genética , Receptores de Estrógenos/análisis , Receptores de Estrógenos/genética , Receptores de Progesterona/genética , Análisis de Supervivencia
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