RESUMEN

Maize tortilla is the best-recognized food product of Mexican gastronomy. Artisanal maize tortillas (AMT) are prepared with native maize varieties and a traditional process. The aims of this study were to identify sensory attributes, texture, and color in AMT that allow them to be differentiated from commercial tortillas, and to determine the chemical and mineral composition of both types of tortillas. Six landraces related to four Mexican maize races were used. Two commercial tortillas were included as references (tortillería and supermarket). Tortillas were subjected to sensory analysis by the modified Flash technique, texture and color were measured objectively and chemical and mineral analysis of all tortillas were evaluated. Lime taste and lime smell attributes were relevant to differentiate AMT from commercial tortillas; aftertaste and fracturability attributes were highly associated to supermarket tortillas. The fracturability attribute of tortillas is consider undesirable for taco preparation. Five of the six AMT were characterized by the presence of a layer, a characteristic that is associated with traditional tortilla made by Mexican consumer. Regarding chemical composition, supermarket tortillas exhibited the highest dietary fiber content (17.09%), but showed 30% more Na than AMT, with the exception of tortillas from Purepecha native variety. Besides, supermarket tortilla had 48.9% less Ca than AMT. The sensory attributes relevant to differentiate native maize tortillas from the commercial maize tortilla references were appearance, smell, and taste, while textural and color attributes played a lesser role.

RESUMEN

Zea mays and Sorghum bicolor are important crops for animal and human nutrition worldwide. In the Central Highland Valley of Mexico, both crops are extremely important, and research is aimed toward increasing yield, disease resistance, and crop adaptation from 1,900- to 2,700-m elevation. In a 3-year field breeding experiment (2004 to 2006), leaf blight and vascular wilt symptoms were frequently observed in contiguous plots of maize and sorghum crops in Montecillo, Mexico and maize plots in Tecamac, Mexico. To identify and characterize the causal agent of these symptoms, isolations were conducted on leaves from areas where healthy and diseased tissues converged. Leaf sections of 1 cm2 from both crops were disinfested, placed on casamino acid-peptone-glucose (CPG) medium, and incubated at 28°C. After 48 h, only yellow colonies were observed and 12 isolates were selected for further characterization. Physiological and biochemical tests indicated that the isolates were nonfluorescent on King's B medium, and API 50 CHE (bioMérieux, Marcy l'Etoile, France) revealed that they were negative for gelatin hydrolysis, indole production, acid production from raffinose and positive for utilization of glycerol, D-glucose, mannitol, arbutine, esculine, salicine, cellobiose, maltose, melibiose, D-fucose, and D-arabitol; all characteristics of Pantoea agglomerans. Further identification of these isolates was accomplished by DNA analysis. For DNA analysis, 1.4-kbp fragments of the 16S rRNA gene were amplified with primer set 8F/1492R (3) and sequenced with U514F/800R universal primers (2). Five sequences were obtained and deposited in GenBank (Accession Nos. EF050806 to EF050810). A phylogenetic tree was constructed using the UPGMA method (mega version 3.1). Results of the phylogenetic analysis grouped the species P. ananatis, P. stewartti, and P. agglomerans into three clusters. The five unknown sequences were grouped into the P. agglomerans cluster. There was a 98 to 99% similarity of the five 16S rRNA gene sequences with P. agglomerans strain type ATCC 27155. Pathogenicity of the 12 isolates was confirmed by injecting 108 CFU mL-1 of inoculum into stems of 3-week-old maize cv. Triunfo and sorghum cold tolerant hybrid (A1×B5)×R1 seedlings in the greenhouse at 28°C and 80% relative humidity. Also, seedlings were inoculated with water, nonpathogenic isolates of P. agglomerans from maize (GM13, and HLA1), and not inoculated as negative controls. Three replications were included for each isolate and control. All test strains developed water-soaked lesions on juvenile leaves at 8 days postinoculation and were followed by chlorotic to straw-colored leaf streaks and then leaf blight symptoms at 3 weeks postinoculation. All negative control seedlings did not develop symptoms. In addition, the 12 isolates were infiltrated at 107 CFU mL-1 into tobacco leaves that displayed a hypersensitive response at 4 days, indicating the presence of the type III secretion system (1). Isolates were reisolated, and the 16S rRNA gene fragments were 100% similar to their original isolate sequences. P. agglomerans has been reported to affect other crops, including chinese taro in Brazil (2007), onion in the United States (2006) and South Africa (1981), and pearl millet in Zimbabwe (1997); however, to our knowledge, this is the first report of P. agglomerans associated with leaf blight and vascular wilt symptoms in maize and sorghum in the Central Highland Valley of Mexico. References: (1) J. Alfano and A. Collmer. Annu. Rev. Phytopathol 42:385, 2004. (2) Y. Anzai et al. Int. J. Syst. Evol. Microbiol. 50:1563, 2000. (3) M. Sasoh et al. Appl. Environ. Microbiol. 72:1825, 2006.

RESUMEN

INTRODUCTION: Several reports of new cases of CNS demyelination or reactivation of MS after hepatitis B vaccination have raised the possibility of a causal relationship. Conversely, some authors have concluded that the risk of developing a demyelinating CNS event after a hepatitis B vaccination is unknown. PATIENTS AND METHODS: We have observed a 40 year old man, with diabetes mellitus (DM) type 1 and a previous history of recurrent acute demyelinating encephalomyelitis (rADEM). The patient had experienced three episodes of neurological dysfunction and he fulfilled the criteria for definite clinical MS but MRI showed demyelinating lesions in the pons and cerebellum without MRI criteria of MS. CSF analysis showed oligoclonal banding. The patient had been clinically stable during the last 6 years. Yearly MRI during this period had not shown any new disease activity. He was admitted in our MS Clinic due to dizziness, nausea, vomiting and diplopia, 6 weeks after the first of the two injections for hepatitis B vaccine after participating in the national programme of vaccination in DM type 1 patients. Clinical examination showed intranuclear ophtalmoplegia, visual loss in the left eye and worsening of the previous cerebellar and pyramidal signs. MRI showed an increase in the old lesions with high intensity signals on T2 weighted sequences with post gadolinium enhancement on T1 weighted sequences located in the brainstem and mesencephalon. The patient s diabetes mellitus deteriorated with ketoacidosis that needed increased doses of insulin. His condition worsened and he developed partial motor seizures. He improved 15 days later but he still had involvement of the cerebellar and pyramidal systems and occasional dizziness. CONCLUSIONS: As pointed out by some authors and in view of this observation, it would seem reasonable, as a precautionary measure, to avoid hepatitis B vaccination in patients with a personal or family history of symptoms suggestive of a demyelinating disease of the CNS.

Asunto(s)

RESUMEN

La neumonitis por radiación es un síndrome acompañado de cambios radiológicos bien definidos a nivel pulmonar. Su presentación e intensidad están ralacionadas con diferentes factores. La frecuencia con que se presenta por irradiación a la mama y sus zonas linfoportadoras es variable. Para conocer la frecuencia y relación que guarda con el antecedente de patología pulmonar previa y asociación a tratamiento secuencial de radioterapia y quimioterapia se estudiaron 62 pacientes con cáncer de mama que recibieron radioterapia al tórax, con seguimiento radiológico mínimo de 52 semanas. En el 29 por ciento de las pacientes (18/62) se presentó el síndrome de neumonitis por radiacipon y el 45 por ciento (28/62) evolucionó a fibrosis pulmonar, con todas las pacientes asintomáticas al cierre del estudio. La patología pulmonar previa fue un factor de riesgo estadísticamente significativo (p=0.04) para el desarrollo de neumonitis y fibrosis pulmonar. Esto no se demostró con la asociación de radioterapia y quimioterapia.

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)