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2.
Clin Nucl Med ; 46(2): e80-e83, 2021 Feb 01.
Article in English | MEDLINE | ID: mdl-33234935

ABSTRACT

ABSTRACT: A 68-year-old man with history of treated prostate cancer was referred to 68Ga-prostate-specific membrane antigen (PSMA)-11 PET/CT imaging. Moderate bone involvement was observed, with a normal liver tracer uptake. Bone biopsy confirmed metastases of prostate cancer. After therapy adjustment, a follow-up 18F-PSMA-1007 PET/CT revealed good response in bone lesions, although it showed 3 new rounded liver intense uptake foci. Concurrent PSA was 0.6 ng/mL. Liver function tests were normal. PET/CT-guided hepatic biopsy demonstrated no malignant cells, focal inflammation, and steatosis, being possibly the inflammation the cause of false-positive multifocal uptake of 18F-PSMA-1007. Following PET/CT, controls showed a normal liver.


Subject(s)
Fluorine Radioisotopes , Liver/diagnostic imaging , Liver/pathology , Niacinamide/analogs & derivatives , Oligopeptides , Positron Emission Tomography Computed Tomography , Aged , Biopsy , Bone Neoplasms/pathology , Bone Neoplasms/secondary , False Positive Reactions , Humans , Inflammation/diagnostic imaging , Male , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/pathology
3.
Rev. méd. Chile ; 148(11)nov. 2020.
Article in Spanish | LILACS | ID: biblio-1389247

ABSTRACT

Background: The prognosis of Non-Hodgkin Lymphoma (NHL) depends on the type of lymphoma, the extension of the disease and the response to therapy. Aim: To evaluate the prognostic value of pretreatment and interim PET/CT compared to classic prognosis factors and body composition measurement (sarcopenia, adipopenia) in patients with recently diagnosed NHL. Material and Methods: Patients with recently diagnosed NHL who had staging 18F-FDG PET/CT performed between December 2008 and August 2018 were selected. Age, gender, weight, height, B symptoms, laboratory tests, pathology, staging PET/CT findings (Ann Arbor, number of nodal groups and extranodal sites involved, Bulky, maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis), Computed Tomography findings (psoas muscle mass index, psoas area, psoas density, subcutaneous fat index (all of them at L3 level), and Deauville score (Lugano Criteria) were recorded. The prognostic value of each of these factors was assessed using Cox multivariable regressions. Results: Of 138 NHL studied patients (median 61 y, 15-87 y, 60.4% men), 31 of them died due to the disease. The median follow-up was 39 months (1-115 months). The strongest prognostic factors were: B symptoms (p < 0.01), anemia (p < 0.01), hypoalbuminemia (p: 0.01), sarcopenia (p < 0.01), adipopenia (p < 0.01), number of node groups involved (p < 0.01), MTV (p < 0.01), and a bad response in interim PET/CT (p < 0.01). In a comparative Cox multivariable analysis, interim PET/CT was the independent variable with the highest significance (p < 0.01). Conclusions: Early treatment response assessed by interim PET/CT is the strongest prognostic factor in NHL patients.


Subject(s)
Female , Humans , Male , Lymphoma, Non-Hodgkin , Positron Emission Tomography Computed Tomography , Prognosis , Lymphoma, Non-Hodgkin/diagnostic imaging , Tomography, X-Ray Computed , Retrospective Studies , Fluorodeoxyglucose F18 , Positron-Emission Tomography
4.
Rev. Méd. Clín. Condes ; 31(2): 150-162, mar.-abr. 2020. ilus, tab
Article in Spanish | LILACS | ID: biblio-1223256

ABSTRACT

Los trastornos del ánimo en el adulto mayor, especialmente aquellos de inicio tardío son difíciles de diferenciar de la demencia en su etapa inicial, dado que existe un traslape sintomático. Esto puede llevar a errar o a retrasar el diagnóstico e impedir la entrega de un tratamiento adecuado. Para el diagnóstico diferencial es fundamental obtener una historia rigurosa tanto del paciente como de la familia, un examen mental y neurológico. Se complementa con un estudio neuropsicológico y con biomarcadores de demencia. Hoy en día se dispone de nuevas técnicas de diagnóstico precoz en la demencia como la volumetría de hipocampos, el PET/CT F18-FDG y PET de amiloide, beta-amiloide y proteína Tau en el LCR, entre otras, que ayudan en casos complejos de diagnóstico diferencial. Este artículo de revisión reúne elementos clínicos y estudios complementarios, con el objetivo de ayudar al psiquiatra en la tarea de diferenciar ambos cuadros.


Mood disorders in the elderly, especially those with late onset are difficult to differentiate from Dementia in its initial stage, given that there is a symptomatic overlap. This can lead to miss or delay the diagnosis and subsequently prevent an appropriate treatment. For the differential diagnosis it is essential to obtain a rigorous history of both the patient and the family, a mental and neurological examination. It is complemented with a neuropsychological assessment and with biomarkers of Dementia. Nowadays, new early diagnosis techniques are available in Dementia such as hippocampal volumetry, PET/CT F18-FDG and PET of amyloid, beta-amyloid and Tau protein in the CSF, among others, which help in complex cases of differential diagnosis. This article reviews clinical elements and complementary studies that help the psychiatrist in the task of differentiating both disorders.


Subject(s)
Humans , Mood Disorders/diagnosis , Dementia/diagnosis , Bipolar Disorder/diagnosis , Mood Disorders/diagnostic imaging , Dementia/diagnostic imaging , Depression/diagnosis , Diagnosis, Differential
5.
Rev Med Chil ; 148(11): 1558-1567, 2020 Nov.
Article in Spanish | MEDLINE | ID: mdl-33844761

ABSTRACT

BACKGROUND: The prognosis of Non-Hodgkin Lymphoma (NHL) depends on the type of lymphoma, the extension of the disease and the response to therapy. AIM: To evaluate the prognostic value of pretreatment and interim PET/CT compared to classic prognosis factors and body composition measurement (sarcopenia, adipopenia) in patients with recently diagnosed NHL. MATERIAL AND METHODS: Patients with recently diagnosed NHL who had staging 18F-FDG PET/CT performed between December 2008 and August 2018 were selected. Age, gender, weight, height, B symptoms, laboratory tests, pathology, staging PET/CT findings (Ann Arbor, number of nodal groups and extranodal sites involved, Bulky, maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis), Computed Tomography findings (psoas muscle mass index, psoas area, psoas density, subcutaneous fat index (all of them at L3 level), and Deauville score (Lugano Criteria) were recorded. The prognostic value of each of these factors was assessed using Cox multivariable regressions. RESULTS: Of 138 NHL studied patients (median 61 y, 15-87 y, 60.4% men), 31 of them died due to the disease. The median follow-up was 39 months (1-115 months). The strongest prognostic factors were: B symptoms (p < 0.01), anemia (p < 0.01), hypoalbuminemia (p: 0.01), sarcopenia (p < 0.01), adipopenia (p < 0.01), number of node groups involved (p < 0.01), MTV (p < 0.01), and a bad response in interim PET/CT (p < 0.01). In a comparative Cox multivariable analysis, interim PET/CT was the independent variable with the highest significance (p < 0.01). CONCLUSIONS: Early treatment response assessed by interim PET/CT is the strongest prognostic factor in NHL patients.


Subject(s)
Lymphoma, Non-Hodgkin , Positron Emission Tomography Computed Tomography , Female , Fluorodeoxyglucose F18 , Humans , Lymphoma, Non-Hodgkin/diagnostic imaging , Male , Positron-Emission Tomography , Prognosis , Retrospective Studies , Tomography, X-Ray Computed
6.
Rev Med Chil ; 147(7): 828-835, 2019 Jul.
Article in Spanish | MEDLINE | ID: mdl-31859980

ABSTRACT

BACKGROUND: Colorectal cancer (CRC) is the third most prevalent cancer in the world and is the second cause of cancer death. Positron emission tomography/computed tomography (PET/CT) using 18F-FDG is used for its staging and follow up. AIM: To assess the occurrence of synchronous colonic and extracolonic tumors detected with contrast-enhanced F18-FDG PET/CT (PET/CTc) in patients with a recently diagnosed CRC. MATERIAL AND METHODS: PET/CTc of 210patients aged 16-91, years (63% men) with a recently diagnosed CRC were reviewed. PET/CTc with incidental findings, not expected to be due to CRC, were followed (laboratory, imaging and pathology) searching for synchronous tumors. RESULTS: Ten patients (4,7%) had a second synchronous CRC. Only 70% of synchronous CRC were accessible to colonoscopy, due mainly to incomplete procedures for stenotic tumors. Extracolonic synchronous neoplasms were detected in 12 patients (5,7%), namely lung cancer in three, renal cell carcinoma in two, non-Hodgkin lymphoma in two, pancreatic cancer in one, breast cancer in one, hepatocellular carcinoma in one, bladder cancer in one and thyroid cancer in one. CONCLUSIONS: Ten percent of patients with a recently diagnosed CRC had a synchronic neoplasm detected at staging using PET/CTc.


Subject(s)
Colorectal Neoplasms/diagnostic imaging , Neoplasms, Multiple Primary/diagnostic imaging , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Neoplasm Staging , Positron Emission Tomography Computed Tomography , Tomography, X-Ray Computed , Young Adult
7.
Rev. méd. Chile ; 147(7): 828-835, jul. 2019. tab, graf
Article in Spanish | LILACS | ID: biblio-1058611

ABSTRACT

Background: Colorectal cancer (CRC) is the third most prevalent cancer in the world and is the second cause of cancer death. Positron emission tomography/computed tomography (PET/CT) using 18F-FDG is used for its staging and follow up. Aim: To assess the occurrence of synchronous colonic and extracolonic tumors detected with contrast-enhanced F18-FDG PET/CT (PET/CTc) in patients with a recently diagnosed CRC. Material and Methods: PET/CTc of 210patients aged 16-91, years (63% men) with a recently diagnosed CRC were reviewed. PET/CTc with incidental findings, not expected to be due to CRC, were followed (laboratory, imaging and pathology) searching for synchronous tumors. Results: Ten patients (4,7%) had a second synchronous CRC. Only 70% of synchronous CRC were accessible to colonoscopy, due mainly to incomplete procedures for stenotic tumors. Extracolonic synchronous neoplasms were detected in 12 patients (5,7%), namely lung cancer in three, renal cell carcinoma in two, non-Hodgkin lymphoma in two, pancreatic cancer in one, breast cancer in one, hepatocellular carcinoma in one, bladder cancer in one and thyroid cancer in one. Conclusions: Ten percent of patients with a recently diagnosed CRC had a synchronic neoplasm detected at staging using PET/CTc.


Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Aged , Aged, 80 and over , Young Adult , Colorectal Neoplasms/diagnostic imaging , Neoplasms, Multiple Primary/diagnostic imaging , Tomography, X-Ray Computed , Positron Emission Tomography Computed Tomography , Neoplasm Staging
8.
Rev. chil. radiol ; 25(1): 26-34, mar. 2019. tab, ilus
Article in Spanish | LILACS | ID: biblio-1003747

ABSTRACT

Resumen:La granulomatosis con poliangeítis (GPA) es una vasculitis sistémica de pequeño vaso, que afecta más frecuentemente el tracto respiratorio y el riñón. Sus criterios diagnósticos se basan en la clínica, exámenes de laboratorio, imágenes e histología. El 90% son ANCA (anticuerpos anticitoplasma de neutrófilos) positivos. La histología muestra inflamación granulomatosa, necrosis y vasculitis. Los exámenes de imagen son de vital importancia en su estudio inicial y seguimiento, correspondiendo principalmente a técnicas tomográficas. La tomografía Computada (TC) es el método de elección para la evaluación de vía aérea superior y pulmón, con alta sensibilidad en afectación de cavidades nasal/paranasales, árbol bronquial y pulmón. La Resonancia Magnética está indicada en compromiso del sistema nervioso central y corazón. El PET/CT presenta alta sensibilidad en enfermedad tóraco-abdominal, es de utilidad en detectar lesiones no visibles con otras técnicas, y en control de tratamiento. El compromiso renal, de alta ocurrencia en GPA, presenta escasa traducción en las imágenes y es frecuentemente indetectable con imágenes, aunque el PET/CT puede ser positivo en casos de glomerulonefritis acentuada. La radiología simple no debe ser utilizada en el estudio de GPA dado su bajo rendimiento diagnóstico. El tratamiento se basa en terapia corticoidea e inmunosupresora. Las recaídas son frecuentes, por lo que estos pacientes requieren seguimiento a largo plazo.


Abstract:Granulomatosis with polyangiitis (GPA) is a systemic type of vasculitis that affects small vessels, most commonly involving the respiratory tract and kidneys. Diagnosis is based on clinical criteria, laboratory tests, imaging and histology. Ninety percent are ANCA (anti-neutrophilic cytoplasmic antibodies) positive. Histology demonstrates granulomatous inflammation, necrosis and vasculitis. Imaging studies are vital for the initial work-up and follow-up. Computed Tomography (CT) is the method of choice for evaluation of the upper airway and lungs, because of its high sensitivity detecting anomalies of paranasal sinuses, bronchial tree and lungs. Magnetic Resonance is indicated for evaluation of the central nervous system and heart. PET/CT has high sensitivity for thoracic and abdominal disease, is useful at detecting lesions not seen with other imaging techniques, and for follow-up. Renal involvement, very frequent on GPA, is usually undetectable at imaging, but may be seen at PET/CT in cases of marked glomerulonephritis. Plain X-rays should not be used for evaluation of GPA because of their low diagnostic performance. Treatment is based on corticosteroid and immunosuppressive therapy. Relapses are frequent, so these patients require long-term follow-up.


Subject(s)
Humans , Tomography, X-Ray Computed , Granulomatosis with Polyangiitis/diagnostic imaging , Positron-Emission Tomography , Granulomatosis with Polyangiitis/complications , Granulomatosis with Polyangiitis/pathology , Kidney Diseases/etiology , Lung Diseases/etiology
10.
Rev. méd. Chile ; 146(4): 413-421, abr. 2018. tab, graf
Article in Spanish | LILACS | ID: biblio-961411

ABSTRACT

Background: Pancreatic cancer is the tenth most prevalent cancer in world, and represents the fourth cause of cancer death. It has a five year-survival of 5%. Aim: To assess the prognostic value of PET/CT in pancreatic cancer. Material and Methods: Sixty-nine patients with pancreatic adenocarcinoma who underwent staging 18F-fluorodeoxyglucose (FDG) PET/CT between December 2008 and July 2016 were selected. Gender, age, body-mass index, laboratory tests (Ca 19-9, hemoglobin, erythrocyte sedimentation rate, liver enzymes, lactate dehydrogenase), histological differentiation of tumor, American Joint Committee on Cancer (AJCC) stage, size and 18F-FDG uptake (maximal stan-dardized uptake value [SUVmax]) of the primary tumor, nodal involvement and distant metastasis detected by PET/CT were registered. Survival was assessed using Kaplan-Meier curves, Log Rank test and Cox multivariable analysis. Results: Mortality was 66.7%, during a mean observation time of 18 months (range 20 days-66 months). Curative surgery, lack of metastases detected by PET/CT, histologically well differentiated tumors, and SUVmax ≤ 4.3 were significantly associated with a better specific survival, determined by the Log Rank test. Histological differentiation was the only variable that had a statistically significant prognostic value in the multivariable analysis. Conclusions: The detection of distant metastases and the intensity of primary tumor 18F-FDG uptake during PET/CT provide useful prognostic information in pancreatic cancer patients.


Subject(s)
Humans , Male , Female , Middle Aged , Aged , Pancreatic Neoplasms/diagnostic imaging , Adenocarcinoma/diagnostic imaging , Pancreatic Neoplasms/mortality , Pancreatic Neoplasms/pathology , Prognosis , Time Factors , Adenocarcinoma/mortality , Adenocarcinoma/pathology , Survival Analysis , Retrospective Studies , Follow-Up Studies , Radiopharmaceuticals/administration & dosage , Radiopharmaceuticals/pharmacokinetics , Fluorodeoxyglucose F18/administration & dosage , Fluorodeoxyglucose F18/pharmacokinetics , Tumor Burden , Neoplasm Grading , Positron Emission Tomography Computed Tomography/methods
11.
Rev. méd. Chile ; 145(11): 1421-1428, nov. 2017. tab, graf
Article in Spanish | LILACS | ID: biblio-902462

ABSTRACT

Background Imaging with F18-fluorodeoxyglucose PET/CT is used to determine sites of abnormal glucose metabolism and can be used to characterize and localize many types of tumors. Aim To assess the prevalence of multiple primary malignant neoplasms (MPMN) detected by PET/CT in cancer patients. Material and Methods F18-fluorodeoxyglucose PET/CT scans performed to 800 patients with a newly diagnosed cancer or with already treated tumors were retrospectively reviewed. In patients whose examination described incidental findings not related to the primary tumor, a research was done about further laboratory, imaging or pathological studies. Results In 188 PET/CT scans (23%) an incidental finding was found. Of these, 66 (35%) were considered as MPMN, 12 as atypical metastases of a known primary tumor, 14 as false positive images (inflammatory or physiologic uptake) and 29 as benign or low grade tumors. In 67 cases (36% of all incidental tumors), the finding was not confirmed. Seven percent of patients with a newly diagnosed tumor had a synchronic MPMN detected by PET/CT. Nine percent of patients with treated tumors developed a metachronous MPMN during their follow up. The most common incidental tumors were thyroid cancer in 15 cases, kidney cancer in 13, lung cancer in 10, colorectal carcinoma in 9, breast cancer in 6, prostate cancer in 4, non-Hodgkin lymphoma in 3 and pancreatic cancer in 2. Conclusions A MPMN is detected by PET/CT in a significant number of cancer patients.


Subject(s)
Humans , Adolescent , Adult , Middle Aged , Aged , Aged, 80 and over , Young Adult , Carcinoma/diagnostic imaging , Positron Emission Tomography Computed Tomography , Neoplasms, Multiple Primary/diagnostic imaging , Carcinoma/classification , Carcinoma/complications , Adenocarcinoma/classification , Adenocarcinoma/complications , Adenocarcinoma/diagnostic imaging , Cross-Sectional Studies , Radiopharmaceuticals , Fluorodeoxyglucose F18 , Early Detection of Cancer/methods , Neoplasms, Multiple Primary/classification , Neoplasms, Multiple Primary/complications
12.
Rev. méd. Chile ; 145(10): 1342-1348, oct. 2017. graf
Article in Spanish | LILACS | ID: biblio-902449

ABSTRACT

Primary colorectal lymphoma is a rare form of presentation of gastrointestinal tract lymphomas. Inflammatory bowel disease and its treatment are risk factors for its development. We report a 47-year-old male patient with Ulcerative Colitis of two years of evolution, treated initially with azathioprine and later on with infliximab. Due to a relapse in symptoms after the second dose of infliximab, a new coloncoscopy was performed showing a rectal ulcerative lesion, corresponding to a large cell Non-Hodgkin's Lymphoma. The patient was successfully treated with RCHOP chemotherapy (Rituximab cyclophosphamide doxorubicin vincristine prednisone). He is currently in disease remission.


Subject(s)
Humans , Male , Middle Aged , Rectal Neoplasms/etiology , Rectal Neoplasms/pathology , Colitis, Ulcerative/drug therapy , Lymphoma, Large B-Cell, Diffuse/etiology , Lymphoma, Large B-Cell, Diffuse/pathology , Immunosuppressive Agents/adverse effects , Rectal Neoplasms/diagnostic imaging , Azathioprine/adverse effects , Vincristine/administration & dosage , Biopsy , Gastrointestinal Agents/adverse effects , Prednisone/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Doxorubicin/administration & dosage , Lymphoma, Large B-Cell, Diffuse/diagnostic imaging , Cyclophosphamide/administration & dosage , Rituximab/administration & dosage , Infliximab/adverse effects , Positron Emission Tomography Computed Tomography
14.
Rev Med Chil ; 145(10): 1342-1348, 2017 Oct.
Article in Spanish | MEDLINE | ID: mdl-29488576

ABSTRACT

Primary colorectal lymphoma is a rare form of presentation of gastrointestinal tract lymphomas. Inflammatory bowel disease and its treatment are risk factors for its development. We report a 47-year-old male patient with Ulcerative Colitis of two years of evolution, treated initially with azathioprine and later on with infliximab. Due to a relapse in symptoms after the second dose of infliximab, a new coloncoscopy was performed showing a rectal ulcerative lesion, corresponding to a large cell Non-Hodgkin's Lymphoma. The patient was successfully treated with RCHOP chemotherapy (Rituximab cyclophosphamide doxorubicin vincristine prednisone). He is currently in disease remission.


Subject(s)
Colitis, Ulcerative/drug therapy , Immunosuppressive Agents/adverse effects , Lymphoma, Large B-Cell, Diffuse/etiology , Lymphoma, Large B-Cell, Diffuse/pathology , Rectal Neoplasms/etiology , Rectal Neoplasms/pathology , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Azathioprine/adverse effects , Biopsy , Cyclophosphamide/administration & dosage , Doxorubicin/administration & dosage , Gastrointestinal Agents/adverse effects , Humans , Infliximab/adverse effects , Lymphoma, Large B-Cell, Diffuse/diagnostic imaging , Male , Middle Aged , Positron Emission Tomography Computed Tomography , Prednisone/administration & dosage , Rectal Neoplasms/diagnostic imaging , Rituximab/administration & dosage , Vincristine/administration & dosage
15.
Rev. chil. radiol ; 22(1): 35-38, 2016. ilus
Article in Spanish | LILACS | ID: lil-782654

ABSTRACT

Brain F18-FDG Positron Emission Tomography (PET) has been used for studying focal epilepsy, with high sensitivity in detection of epileptogenic foci, even with normal magnetic resonance imaging (MRI). Some cases of Landau-Kleffner Syndrome (LKS) have shown PET abnormalities, mostly showing uni- or bilateral temporoparietal hypometabolism, although a heterogeneous group of alterations have been described. We report a case of LKS with a left hypermetabolic temporo-occipital area that responded to treatment, with clinical improvement and remission of PET hypermetabolic focus.


La positron emission tomography (PET) cerebral con F18-FDG ha sido utilizado para estudiar epilepsias focales con alta sensibilidad en la detección del área epileptógena, aun con resonancia magnética (RM) normal. La PET ha mostrado positividad en algunos casos de síndrome de Landau-Kleffner (SLK), la mayoría de las veces evidenciando hipometabolismo temporoparietal uni o bilateral, aunque un grupo heterogéneo de alteraciones asociadas ha sido descrito. Presentamos un caso de SLK con un área hipermetabólica temporooccipital izquierda, que respondió al tratamiento, con mejoría clínica y regresión del foco hipercaptante a la PET.


Subject(s)
Humans , Male , Child , Landau-Kleffner Syndrome/metabolism , Landau-Kleffner Syndrome/diagnostic imaging , Positron-Emission Tomography , Fluorodeoxyglucose F18 , Epilepsy/diagnostic imaging
16.
BMC Genomics ; 15: 1056, 2014 Dec 03.
Article in English | MEDLINE | ID: mdl-25471115

ABSTRACT

BACKGROUND: Understanding gene expression and metabolic re-programming that occur in response to limiting nitrogen (N) conditions in crop plants is crucial for the ongoing progress towards the development of varieties with improved nitrogen use efficiency (NUE). To unravel new details on the molecular and metabolic responses to N availability in a major food crop, we conducted analyses on a weighted gene co-expression network and metabolic profile data obtained from leaves and roots of rice plants adapted to sufficient and limiting N as well as after shifting them to limiting (reduction) and sufficient (induction) N conditions. RESULTS: A gene co-expression network representing clusters of rice genes with similar expression patterns across four nitrogen conditions and two tissue types was generated. The resulting 18 clusters were analyzed for enrichment of significant gene ontology (GO) terms. Four clusters exhibited significant correlation with limiting and reducing nitrate treatments. Among the identified enriched GO terms, those related to nucleoside/nucleotide, purine and ATP binding, defense response, sugar/carbohydrate binding, protein kinase activities, cell-death and cell wall enzymatic activity are enriched. Although a subset of functional categories are more broadly associated with the response of rice organs to limiting N and N reduction, our analyses suggest that N reduction elicits a response distinguishable from that to adaptation to limiting N, particularly in leaves. This observation is further supported by metabolic profiling which shows that several compounds in leaves change proportionally to the nitrate level (i.e. higher in sufficient N vs. limiting N) and respond with even higher levels when the nitrate level is reduced. Notably, these compounds are directly involved in N assimilation, transport, and storage (glutamine, asparagine, glutamate and allantoin) and extend to most amino acids. Based on these data, we hypothesize that plants respond by rapidly mobilizing stored vacuolar nitrate when N deficit is perceived, and that the response likely involves phosphorylation signal cascades and transcriptional regulation. CONCLUSIONS: The co-expression network analysis and metabolic profiling performed in rice pinpoint the relevance of signal transduction components and regulation of N mobilization in response to limiting N conditions and deepen our understanding of N responses and N use in crops.


Subject(s)
Gene Expression Regulation, Plant , Gene Regulatory Networks , Metabolic Networks and Pathways , Nitrates/metabolism , Oryza/genetics , Oryza/metabolism , Cluster Analysis , Computational Biology , Epigenesis, Genetic , Gene Expression Profiling , Metabolome , Metabolomics , Molecular Sequence Annotation , Multigene Family , Organ Specificity , Plant Leaves/genetics , Plant Leaves/metabolism , Plant Roots/genetics , Plant Roots/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism
17.
BMC Genomics ; 15: 681, 2014 Aug 13.
Article in English | MEDLINE | ID: mdl-25128291

ABSTRACT

BACKGROUND: High density stress, also known as intraspecies competition, causes significant yield losses in a wide variety of crop plants. At the same time, increases in density tolerance through selective breeding and the concomitant ability to plant crops at a higher population density has been one of the most important factors in the development of high yielding modern cultivars. RESULTS: Physiological changes underlying high density stress were examined in Oryza sativa plants over the course of a life cycle by assessing differences in gene expression and metabolism. Moreover, the nitrogen limitation was examined in parallel with high density stress to gain a better understanding of physiological responses specific to high density stress. While both nitrogen limitation and high density resulted in decreased shoot fresh weight, tiller number, plant height and chlorophyll content, high density stress alone had a greater impact on physiological factors. Decreases in aspartate and glutamate concentration were found in plants grown under both stress conditions; however, high density stress had a more significant effect on the concentration of these amino acids. Global transcriptome analysis revealed a large proportion of genes with altered expression in response to both stresses. The presence of ethylene-associated genes in a majority of density responsive genes was investigated further. Expression of ethylene biosynthesis genes ACC synthase 1, ACC synthase 2 and ACC oxidase 7 were found to be upregulated in plants under high density stress. Plants at high density were also found to up regulate ethylene-associated genes and senescence genes, while cytokinin response and biosynthesis genes were down regulated, consistent with higher ethylene production. CONCLUSIONS: High density stress has similar but greater impact on plant growth and development compared to nitrogen limitation. Global transcriptome changes implicate ethylene as a volatile signal used to communicate proximity in under dense population growth condition and suggest a role for phytohormones in high density stress response in rice plants.


Subject(s)
Ethylenes/metabolism , Gene Expression Profiling , Metabolomics , Nitrogen/metabolism , Oryza/genetics , Oryza/metabolism , Stress, Physiological , Aspartic Acid/metabolism , Genes, Plant/genetics , Glutamic Acid/metabolism , Oryza/growth & development , Oryza/physiology
18.
BMC Plant Biol ; 14: 127, 2014 May 09.
Article in English | MEDLINE | ID: mdl-24886417

ABSTRACT

BACKGROUND: Agrobacterium tumefaciens-based transient assays have become a common tool for answering questions related to protein localization and gene expression in a cellular context. The use of these assays assumes that the transiently transformed cells are observed under relatively authentic physiological conditions and maintain 'normal' sub-cellular behaviour. Although this premise is widely accepted, the question of whether cellular organization and organelle morphology is altered in Agrobacterium-infiltrated cells has not been examined in detail. The first indications of an altered sub-cellular environment came from our observation that a common laboratory strain, GV3101(pMP90), caused a drastic increase in stromule frequency. Stromules, or 'stroma-filled-tubules' emanate from the surface of plastids and are sensitive to a variety of biotic and abiotic stresses. Starting from this observation, the goal of our experiments was to further characterize the changes to the cell resulting from short-term bacterial infestation, and to identify the factor responsible for eliciting these changes. RESULTS: Using a protocol typical of transient assays we evaluated the impact of GV3101(pMP90) infiltration on chloroplast behaviour and morphology in Nicotiana benthamiana. Our experiments confirmed that GV3101(pMP90) consistently induces stromules and alters plastid position relative to the nucleus. These effects were found to be the result of strain-dependant secretion of cytokinin and its accumulation in the plant tissue. Bacterial production of the hormone was found to be dependant on the presence of a trans-zeatin synthase gene (tzs) located on the Ti plasmid of GV3101(pMP90). Bacteria-derived cytokinins were also correlated with changes to both soluble sugar level and starch accumulation. CONCLUSION: Although we have chosen to focus on how transient Agrobacterium infestation alters plastid based parameters, these changes to the morphology and position of a single organelle, combined with the measured increases in sugar and starch content, suggest global changes to cell physiology. This indicates that cells visualized during transient assays may not be as 'normal' as was previously assumed. Our results suggest that the impact of the bacteria can be minimized by choosing Agrobacterium strains devoid of the tzs gene, but that the alterations to sub-cellular organization and cell carbohydrate status cannot be completely avoided using this strategy.


Subject(s)
Agrobacterium tumefaciens/metabolism , Biological Assay/methods , Cytokinins/pharmacology , Nicotiana/metabolism , Plastids/metabolism , Starch/metabolism , Agrobacterium tumefaciens/genetics , Gene Expression/drug effects , Genes, Bacterial , Genes, Reporter , Genetic Vectors/metabolism , Phenotype , Plastids/drug effects , Nicotiana/drug effects , Transformation, Genetic/drug effects
19.
PLoS One ; 9(5): e96158, 2014.
Article in English | MEDLINE | ID: mdl-24788752

ABSTRACT

Plants grown under inadequate mineralized nitrogen (N) levels undergo N and carbon (C) metabolic re-programming which leads to significant changes in both soluble and insoluble carbohydrate profiles. However, relatively little information is available on the genetic factors controlling carbohydrate partitioning during adaptation to N-limitation conditions in plants. A gene encoding a uridine-diphospho-(UDP)-glucose 4-epimerase (OsUGE-1) from rice (Oryza sativa) was found to be N-responsive. We developed transgenic rice plants to constitutively over-express the OsUGE-1 gene (OsUGE1-OX1-2). The transgenic rice lines were similar in size to wild-type plants at the vegetative stage and at maturity regardless of the N-level tested. However, OsUGE1-OX lines maintained 18-24% more sucrose and 12-22% less cellulose in shoots compared to wild-type when subjected to sub-optimal N-levels. Interestingly, OsUGE1-OX lines maintained proportionally more galactose and glucose in the hemicellulosic polysaccharide profile of plants compared to wild-type plants when grown under low N. The altered cell wall C-partitioning during N-limitation in the OsUGE1-OX lines appears to be mediated by OsUGE1 via the repression of the cellulose synthesis associated genes, OsSus1, OsCesA4, 7, and 9. This relationship may implicate a novel control point for the deposition of UDP-glucose to the complex polysaccharide profiles of rice cell walls. However, a direct relationship between OsUGE1 and cell wall C-partitioning during N-limitation requires further investigation.


Subject(s)
Cell Wall/metabolism , Nitrogen/metabolism , Oryza/enzymology , Plant Proteins/metabolism , UDPglucose 4-Epimerase/metabolism , Carbohydrate Metabolism , Cell Wall/enzymology , Cellulose/metabolism , Gene Expression Regulation, Plant , Oryza/cytology , Oryza/genetics , Plant Proteins/genetics , Plant Shoots/metabolism , Plants, Genetically Modified/enzymology , Plants, Genetically Modified/genetics , Sucrose/metabolism , UDPglucose 4-Epimerase/genetics , Uridine Diphosphate Glucose/metabolism
20.
Rev Med Chil ; 141(1): 41-8, 2013 Jan.
Article in Spanish | MEDLINE | ID: mdl-23732413

ABSTRACT

BACKGROUND: PET/CT (Positron emission tomography/computed tomography) is a hybrid image modality widely used in oncology, for staging, therapy evaluation or follow up. AIM: To evaluate the prognostic value of PET/CT in lung cancer. MATERIAL AND METHODS: Retrospective review of PET/CT records, selecting 51 patients with a lung malignancy, mass or nodule referred for PET/CT between December 2008 and December 2010. All had pathological confirmation of malignancy and had not been treated previously. Age, gender, body mass index, radiological features of lung tumor and metastases, and lung tumor 18F-fluoro-2-deoxy-d-glucose uptake using the SUV (Standardized uptake value) index were recorded. Survival was analyzed using Kaplan-Meier curves and a Cox proportional regression analysis. RESULTS: Pathology confirmed the presence of lung cancer in 47 patients aged 30 to 88 years. Four patients (7.8%) had other type of tumors such as carcinoid or lymphoma. Fifty percent of lung cancer patients died during a mean observation lapse of 18 months (range: 2-34 months). Patients with metastases, local lymph node involvement, a lung tumor size > 3 cm and high tumor uptake (SUVmax > 6) had significantly lower survival. Occurrence of metastases was the only independent prognostic factor in the Cox regression. A lung lesion with a SUVmax ≥ 12 was always associated to hilar/mediastinal lymph node involvement. CONCLUSIONS: PET/CT imaging gives important prognostic information in lung cancer patients.


Subject(s)
Adenocarcinoma/diagnostic imaging , Carcinoma, Squamous Cell/diagnostic imaging , Fluorodeoxyglucose F18 , Lung Neoplasms/diagnostic imaging , Lymph Nodes/diagnostic imaging , Multimodal Imaging/methods , Radiopharmaceuticals , Adenocarcinoma/secondary , Adult , Aged , Aged, 80 and over , Carcinoma, Squamous Cell/secondary , Epidemiologic Methods , Female , Humans , Lung Neoplasms/mortality , Lung Neoplasms/pathology , Lymphatic Metastasis , Male , Mediastinum/diagnostic imaging , Middle Aged , Positron-Emission Tomography , Prognosis , Risk Factors , Time Factors , Tomography, X-Ray Computed
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