Repeated loss of the ability of a wild pepper disease resistance gene to function at high temperatures suggests that thermoresistance is a costly trait.

Specificity in plant-pathogen gene-for-gene (GFG) interactions is determined by the recognition of pathogen proteins by the products of plant resistance (R) genes. The evolutionary dynamics of R genes in plant-virus systems is poorly understood. We analyse the evolution of the L resistance locus to tobamoviruses in the wild pepper Capsicum annuum var. glabriusculum (chiltepin), a crop relative undergoing incipient domestication. The frequency, and the genetic and phenotypic diversity, of the L locus was analysed in 41 chiltepin populations under different levels of human management over its distribution range in Mexico. The frequency of resistance was lower in Cultivated than in Wild populations. L-locus genetic diversity showed a strong spatial structure with no isolation-by-distance pattern, suggesting environment-specific selection, possibly associated with infection by the highly virulent tobamoviruses found in the surveyed regions. L alleles differed in recognition specificity and in the expression of resistance at different temperatures, broad-spectrum recognition of P0 + P1 pathotypes and expression above 32°C being ancestral traits that were repeatedly lost along L-locus evolution. Overall, loss of resistance co-occurs with incipient domestication and broad-spectrum resistance expressed at high temperatures has apparent fitness costs. These findings contribute to understand the role of fitness trade-offs in plant-virus coevolution.

Tobacco Mild Green Mosaic Virus (TMGMV) Isolates from Different Plant Families Show No Evidence of Differential Adaptation to Their Host of Origin.

The relevance of tobamoviruses to crop production is increasing due to new emergences, which cannot be understood without knowledge of the tobamovirus host range and host specificity. Recent analyses of tobamovirus occurrence in different plant communities have shown unsuspectedly large host ranges. This was the case of the tobacco mild green mosaic virus (TMGMV), which previously was most associated with solanaceous hosts. We addressed two hypotheses concerning TMGMV host range evolution: (i) ecological fitting, rather than genome evolution, determines TMGMV host range, and (ii) isolates are adapted to the host of origin. We obtained TMGMV isolates from non-solanaceous hosts and we tested the capacity of genetically closely related TMGMV isolates from three host families to infect and multiply in 10 hosts of six families. All isolates systemically infected all hosts, with clear disease symptoms apparent only in solanaceous hosts. TMGMV multiplication depended on the assayed host but not on the isolate's host of origin, with all isolates accumulating to the highest levels in Nicotiana tabacum. Thus, results support that TMGMV isolates are adapted to hosts in the genus Nicotiana, consistent with a well-known old virus-host association. In addition, phenotypic plasticity allows Nicotiana-adapted TMGMV genotypes to infect a large range of hosts, as encountered according to plant community composition and transmission dynamics.

Environment and host genotype determine the outcome of a plant-virus interaction: from antagonism to mutualism.

It has been hypothesized that plant-virus interactions vary between antagonism and conditional mutualism according to environmental conditions. This hypothesis is based on scant experimental evidence, and to test it we examined the effect of abiotic factors on the Arabidopsis thaliana-Cucumber mosaic virus (CMV) interaction. Four Arabidopsis genotypes clustering into two allometric groups were grown under six environments defined by three temperature and two light-intensity conditions. Plants were either CMV-infected or mock-inoculated, and the effects of environment and infection on temporal and resource allocation life-history traits were quantified. Life-history traits significantly differed between allometric groups over all environments, with group 1 plants tolerating abiotic stress better than those of group 2. The effect of CMV infection on host fitness (virulence) differed between genotypes, being lower in group 1 genotypes. Tolerance to abiotic stress and to infection was similarly achieved through life-history trait responses, which resulted in resource reallocation from growth to reproduction. Effects of infection varied according to plant genotype and environment from detrimental to beneficial for host fitness. These results are highly relevant and demonstrate that plant viruses can be pleiotropic parasites along the antagonism-mutualism continuum, which should be considered in analyses of the evolution of plant-virus interactions.

Glycolytic activity with 18F-FDG PET/CT predicts final neoadjuvant chemotherapy response in breast cancer.

The purpose of the present study is to explore the relation between glycolytic metabolism assessed by (18)F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) and final neoadjuvant chemotherapy (NC) response in locally advanced breast tumors. Of women with breast cancer, 126 were prospectively evaluated. All patients underwent (18)F-FDG PET/CT previous to NC. Standard uptake value (SUV) max was calculated in the primary tumor. After NC, residual primary tumor specimen was histopathologically classified according to Miller and Payne tumor regression grades (TRG), from G1 to G5 and in response groups as good responders (G4 or G5), partial responders (G2 or G3), and non-responders (G1). Furthermore, residual lesions were classified following a binary assessment as responders (G4 or G5) and non-responders (the rest of cases). The relationship between SUV max with TRG and response groups was evaluated. Of tumors, 127 were assessed (a patient had bilateral breast lesions). TRG were as follows: G1 (27), G2 (27), G3 (32), G4 (11), and G5 (30). Forty-one were classified as good responders, 59 as partial responders, and 27 as non-responders. For the binary assessment, 41 lesions were classified as responders and 86 as non-responders. We found statistical differences (p=0.02) between the mean SUV max and TRG with greater SUV values for G5 compared to the other TRG. Good responders showed greater mean SUV max ± SD compared to partial responders and non-responders (10.51 ± 6.64 for good responders, 6.94 ± 5.81 for partial responders, and 5.23 ± 2.76 for non-responders; p=0.001). Baseline tumor metabolism assessing by FDG PET/CT was associated with the final histopathologic status after neoadjuvant chemotherapy, with greater SUV max values for good responders compared to the less responder cancers.

Early and delayed prediction of axillary lymph node neoadjuvant response by (18)F-FDG PET/CT in patients with locally advanced breast cancer.

PURPOSE: To determine the utility of (18)F-FDG (FDG) PET/CT performed in an early and delayed phase during neoadjuvant chemotherapy in the prediction of lymph node histopathological response in patients with locally advanced breast cancer. METHODS: FDG PET/CT studies performed in 76 patients (mean age 53 years) at baseline (PET-1), after the second course of chemotherapy (PET-2) and after the last course of chemotherapy (PET-3) were prospectively analysed. Inclusion criteria were lymph node involvement detected by PET/CT and non-sentinel node biopsy before or after the baseline PET/CT scan. Following the recommendations of the 12th International Breast Conference (St. Gallen), the patients were divided into five subgroups in relation to biological prognostic factors by immunohistochemistry. For diagnosis visual and semiquantitative analyses was performed. Absence of detectable lymph node uptake on the PET-2 or PET-3 scan with respect to the PET-1 scan was considered metabolic complete response (mCR). Lymph nodes were histopathologically classified according the lymph node regression grade and in response groups as pathological complete response (pCR) or not pCR (type A/D or B/C of the Smith grading system, respectively). ROC analysis was performed to determine a cut-off value of Δ% SUV1-2 and SUV1-3 for prediction of nodal status after chemotherapy. An association between mCR and pCR was found (Cohen's kappa analysis), and associations between phenotypes and metabolic behaviour and the final histopathological status were also found. RESULTS: Lymph node pCR was seen in 34 patients. The sensitivity, specificity, and positive and negative predictive values of PET-2 and PET-3 in establishing the final status of the axilla after chemotherapy were 52 %, 45 %, 50 % and 47 %, and 33 %, 84 %, 67 % and 56 %, respectively. No significant relationship was observed between mCR on PET-2 and PET-3 and pCR (p = 0.31 and 0.99, respectively). Lymph node metabolism on PET-1 was not able to predict the final histopathological status, whereas basal carcinomas showed a higher rate of pCR (70.6 %) than the other groups (p = 0.03). CONCLUSION: FDG PET/CT seems to have limitations in both the early and delayed evaluation of lymph node status after chemotherapy, with reduced predictive values.

Semi-quantitative lymph node assessment of (18)F-FDG PET/CT in locally advanced breast cancer: correlation with biological prognostic factors.

PURPOSE: The aim of this study was to analyse the correlation between dual-time-point (18)F-2-deoxy-2-fluoro-D-glucose (FDG) uptakes in lymph nodes assessed by positron emission tomography (PET)/CT and histopathological and immunohistochemical prognostic factors. METHODS: Seventy-five women with locally advanced breast cancer were prospectively evaluated. PET/CT was requested in the initial staging previous to adjuvant chemotherapy (multicentre study). All of the patients underwent (18)F-FDG PET/CT with a dual-time-point acquisition. Both examinations were evaluated qualitatively and semi-quantitatively with calculation of maximum standardized uptake values (SUV(max)) in PET-1 (SUV-1) and in PET-2 (SUV-2) and the percentage variation of the SUV or retention index (RI) between PET-1 and PET-2 in lymph nodes with the greater (18)F-FDG uptake. The biological prognostic parameters such as the steroid receptor status, p53 and HER2 expression, proliferation rate (Ki-67) and grading were determined from tissue of the primary tumour. Metabolic and biological parameters were correlated using Spearman's rank-order correlation coefficient and Mann-Whitney U and Kruskal-Wallis tests. RESULTS: Negative receptor status was correlated with higher SUV-1, SUV-2 and RI in lymph nodes. The results were significant for progesterone receptor status. p53 over-expression and triple-negative status were associated with greater semi-quantitative parameters in lymph nodes. Higher tumoural grades were related with greater semi-quantitative parameters (p > 0.05). CONCLUSION: Biological factors of bad prognosis were correlated with higher semi-quantitative metabolic values in lymph nodes. Therefore these results appear to reveal biological significance of lymph node (18)F-FDG accumulation.

Asociación de trastuzumab con mayor incidencia de metástasis cerebrales en pacientes con cáncer de mama HER2 positivo / Trastuzumab’s association with cerebral metastases and meningeal carcinomatosis in a patient with HER2-positive breast cancer

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Efecto del adenoma hipofisario sobre la función tiroidea y su evolución después de la microcirugia transesfenoidal / Effect of pituitary adenomas on thyroid function and its evolotion after surgery

Se estudió la función tiroidea en 38 pacientes, 20 mujeres y 18 hombres, quienes tenían el diagnóstico de tumor hipofisario, antes y después de adenomectomía transesfenoidal. Veinte pacientes presentaban acromegalia, 7 prolactinoma y 11 adenoma "no funcionante". Por tomografía craneal computada se demostró la presencia de tumor dentro de la silla turca en 15 pacientes y con extensión extraselarr en los otros 23. Se hicieron determinaciones en suero de T3, T4, T4L y TSH, por medio de radioinmunoanálisis. Se consideró como hipotiroidismo bioquímico a la asociación de T4L < 1.2 ug/ml y TSH < 5uU/ml. Con base en los resultados de las pruebas de funcionamiento tiroideo (PFT) y el tamaño del adenoma. Se formaron cuatro grupos de pacientes: el grupo I con adenoma intraselar y PFT normales (n = 12), el II con adenoma intraselar y PFT anormales (n = 3), el III con extensión extraselarr y PFT normales (n = 15) y el IV extensión extraselarr y PFT anormales (n = 8). A los tres meses de la cirugía se encontró déficit de la función tiroidea en un paciente del grupo I, en ninguno del II, en cinco del III y en tres del IV. Los pacientes con tumor intraselar presentaron una menor frecuencia de hipotiroidismo bioquímico en comparación con los pacientes con extensión extraselar (p < 0,5). Estos resultados indican: 1) el adenoma hipofisario se puede encontrar asociado con una alteración bioquímica de la función tiroidea, en ausencia de datos clínicos. 2) la adenomectomía puede conservar o normalizar la función tiroidea en la mayor parte de los pacientes con tumor intraselar y 3) el tumor hipofisario de gran tamaño tiene un mal pronóstico en cuanto a la conservación o recuperación de la función tiroidea después de la cirugía

La reacción paradójica a la TRH en la enfermedad de Cushing no es una prueba diagnóstica cinfiable / The paradoxical response to TRH in Cushing's disease is not a reliable diagnostic test

En sólo uno de seis pacientes con enfermedad de Cushing dependiente de un tumor de la hipófisis se obtuvo un incremento paradójico de ACTH y cortisol plasmáticos despúes de la administración de TRH. Por lo contrario, todos los pacientes mostraron un incremento normal de los niveles séricos de TSH y prolactina como reacción a la aplicación de TRH. Se presentan las características clínicas y bioquímicas de cada caso. Los datos obtenidos confirman la impresión general acerca de la inutilidad de la prueba de TRH para el diagnóstico de la enfermedad de Cushingg

Acromegalia y apoplejía hipofisaria: informe de un caso / Acromegaly and pituitary apoplexy

Se describe el cuadro clínico y hormonal de un paciente de 38 años con tumor hipofisario causante de acromegalia, quien en forma súbita desarrolló apoplejía hipofisaria de la que se recuperó sin requerir operación inmediata. Posteriormente se decidió evacuar quirúrgicamente el contenido de la silla turca para prevenir la recurrencia o descartar la presencia de tumoración intracraneal

La diabetes insípida como complicación de la cirugía de hipófisis / Diabetes insipidus as a complication of pituitary surgery

Se presenta una revisión de 52 pacientes a quienes se diagnosticó un tumor hipofisario y fueron sometidos a cirugía de la hipófisis por abordaje transesfenoidal (n=42) y por vía cranial (n=10). Se investigó la frecuencia de diabetes insípida que resultó ser de 42.3% en la variedad "transitoria" y de 3.8% en la "permanente". Tal diagnóstico se hizo con base en los índices: volumen urinario > 150 ml/hora, osmolaridad sérica 286 + ou - 4 m Osm.Kg H20 y la relación osmolaridad urinaria/osmolaridad sérica. No se encontró relación con la vía de abordaje quirúrgico, extensión del tumor o tipo de secreción endocrina. En el 80% de los casos la poliuria se presentó en las primeras 16 horas poscirugía y en el 20% en las siguientes 40. El manejo se hizo con reposición de volumen y hormona antidiurética acuosa (Pitressin) en las primeras 48 horas después de la cirugía. En los casos en que persistió la poliuria se usó clorpropamida. La diabetes insípida se presenta frecuentemente como complicación temprana de la cirugía de hipófisis pero su evolución es benigna y el tratamiento sencillo