First Report of Stewart's Wilt of Maize in Argentina Caused by Pantoea stewartii.

Stewart's wilt is a serious disease of corn (Zea mays L.) caused by the bacterium Pantoea stewartii subsp. stewartii (Pss). Typical symptoms of infected fields and dent corn are longitudinal streaks with irregular or wavy margins, which are parallel to the veins and may extend the length of the leaf. These pale to green yellow lesions become dry and brown as the disease progresses producing a leaf blight (4). During the growing seasons 2010 to 2011 and 2011 to 2012, symptoms of bacterial leaf blight of corn were observed in central Argentina maize fields, with an incidence of 54% in Córdoba province. To identify the pathogen, leaves from 10 symptomatic maize plants per field were collected from 15 fields covering a representative geographical area. High populations of morphologically uniform bacteria were isolated from leaf tissues by conventional methods using King's medium B agar (2). Ten representative facultatively anaerobic gram-negative, non-fluorescing, non-motile, catalase positive and oxidase negative rod-shaped and yellow-pigmented bacterial isolates were evaluated further. The biochemical profile obtained was: fermentative metabolism, negative indol, acetoin and hydrogen sulfide production, negative gelatin hydrolysis (22°C), positive acid production from D-glucose and lactose, negative gas production from D-glucose, and negative nitrate reduction (1). All the isolates produced a 300-bp band with PCR using the species specific primer pair PST3581/PST3909c (3). The Pss ATCC 8199 and Pseudomonas fluorescens ATCC 13525 strains were used as positive and negative controls for the PCR assays, respectively. The pathogenicity test was performed by stem inoculation of five to ten P2069 YR maize plants (one to two leaf growth stage) grown in growth chamber. Plants were inoculated by syringe with a 107 to 108 cell/ml bacterial suspension and kept in a humid chamber at 25 to 27°C. Plants inoculated with Pss ATCC 8199 or with sterile water were used as positive and negative control treatments, respectively. The development of symptoms similar to those originally found in the field was observed on all the plants inoculated with the different isolates at 7 to 10 days post inoculation. In addition, symptoms on inoculated plants were similar to those observed for the positive control treatment. No symptoms were found on negative controls. Koch's postulates were fulfilled since bacteria isolated from symptomatic tissue had identical characteristics to isolates used to inoculate plants and to the reference Pss strain for biochemical tests and PCR reaction mentioned above. To our knowledge, this is the first report of P. stewartii subsp. stewartii isolated from diseased maize in Argentina. References: (1) J. G. Holt et al. Page 179 in: Bergey's manual of determinative bacteriology. Williams and Wilkins, Baltimore, MD, 1994. (2) OEPP/EPPO. Bulletin OEPP/EPPO Bulletin, 36: 111, 2006. Pantoea stewartii subsp. stewartii diagnostic. (3) A. Wensing et al. Appl. Environ. Microbiol. 76:6248, 2010. (4) D. G. White Page 4 in: Compendium of corn disease. The American Phytopathology Society, 1999.

Perineal analgesic actions of epidural clonidine in cattle.

OBJECTIVE: To determine the analgesic, sedative, motor, cardiac and respiratory effects of epidural clonidine in cattle. STUDY DESIGN: Prospective randomized study. ANIMAL POPULATION: Six healthy male cattle weighing between 236 and 365 kg. METHODS: To investigate the effect of epidural clonidine, the animals received 2 and 3 micro g kg(-1) of clonidine diluted to 8 mL with 0.9% saline. Two treatments were utilized as controls. The animals from the first control treatment received 2% lidocaine (0.4 mg kg(-1)) and those from the second received an equal volume of 0.9% saline. Each animal received each treatment in random order. Evaluations of analgesia, sedation, muscle relaxation, heart rate, respiratory rate and rectal temperature were obtained at 0 (basal), 2, 5, 10, 15 and 30 minutes after epidural injection, and then at 30-minute intervals until loss of analgesia occurred. All the animals received a standard noxious stimulus consisting of needle insertion into the skin and deep muscle; a 4-point scale was used to score the response. A second scale was used to score sedation and a third for muscle relaxation. RESULTS: Both doses of clonidine were effective in producing analgesia of the tail, perineum, and upper hindlimb. Complete analgesia was present before (mean +/- SE = 9 +/- 4 vs. 19 +/- 9 minutes) and lasted longer (311 +/- 33 vs. 192 +/- 27 minutes) for the 3 microg kg(-1) versus the 2 microg kg(-1) dose, respectively. A dose-dependent sedative effect of clonidine was also observed, with a peak effect between 60 and 180 minutes. No effects on heart or respiratory rates were observed with either dose of clonidine. CONCLUSIONS: Epidural administration of 2 and 3 micro g kg(-1) of clonidine in cattle in this study provided bilateral perineal analgesia/anesthesia with a dose-dependent onset and duration of action. CLINICAL RELEVANCE: Further studies are required to determine whether the analgesia is sufficient for surgery.

Kinetic study of the hydrolysis of phthalic anhydride and aryl hydrogen phthalates.

The kinetics of the hydrolysis of phthalic anhydride and X-phenyl hydrogen phthalate (X = H, p-Me, m-Cl, and p-Cl) were studied. Several bases accelerate the reaction of phthalic anhydride: acetate, phosphate, N-methyl imidazole, 1,4-diazabicyclo[2,2,2]octane (DABCO), and carbonate. Phosphate, DABCO, and N-methyl imidazole react as nucleophiles, whereas the data do not allow the determination of whether the other bases react in the same way or as general bases catalyzing the water reaction. The rate constants for all of them including water and HO- define a Brönsted plot with beta = 0.46. The kinetics of the hydrolysis of the esters were studied below pH 6.20, and the mechanism involves the formation of phthalic anhydride, which then is hydrolyzed to the phthalic acid. Phenoxide ion has a very high rate constant for the reaction with phthalic anhydride, so above pH 6.20 it competes significantly with the hydrolysis of the anhydride. The reactions of the esters as a function of pH allow the determination of the kinetic pK(a) which are 3.06, 3.02, 2.95, and 2.93 for X = H, p-Me, m-Cl, and p-Cl, respectively. The data also show that the catalysis by the neighboring carboxy group takes place only when it is ionized (i.e., as carboxylate).

Effect of cyclodextrin on the intramolecular catalysis of amide hydrolysis.

The hydrolysis reaction of phthalamic acids (HOOCArCONHR, R = p-NO(2)Ph 1a, Ph 1b, adamantyl 1c) and N-phenyl maleamic acid 2b was studied in the presence of hydroxypropyl-beta-cyclodextrin (HPCD) in acid solution. The reactions of 1a and 1b were studied also in the presence of beta-cyclodextrin (beta-CD). All the compounds formed inclusion complexes with HPCD, and the association constant was determined from the change in absorption of the substrate when the host is added in the case of 1a (90 M(-)(1)) and 2b (49 M(-)(1)). For 1c ( 4 x 10(4) M(-)(1)) a competition method was used, and for 1b the association equilibrium constant was obtained from the kinetic data (37 M(-)(1)) because it is too reactive for the spectrophotometric method. Both cyclodextrins strongly inhibited the reactions, and analysis of the kinetic data for HPCD indicated that the reactions of complexed 1a, 1b, and 2b are at least 10-30 times slower than in the bulk solution whereas 1c reacts only 4.6 times slower when it is complexed. The inhibition is attributed to changes in the geometry of the substrate due to interaction of the carboxylic group and/or the amide with the OH at the rim of the cyclodextrin. The differences in the relative effect observed for 1c are attributed to the formation of a tighter complex with this substrate.

Hydroxypropyl-beta-cyclodextrin enhanced fluorimetric method for the determination of melatonin and 5-methoxytryptamine.

The effects of native cyclodextrins (alpha, beta or gamma), hydroxypropyl-beta-cyclodextrin, beta-cyclodextrin solubilized in urea, soluble starch and glucose in water solution on the fluorescence behaviour of melatonin (N-acetyl-5-methoxytryptamine) (M) and 5-methoxytryptamine [5-methoxy-3-(2-aminoethyl)indole] (5M) were determined. In addition, the effect of methanol and propanol with and without beta-cyclodextrin or hydroxypropyl-beta-cyclodextrin was assessed. From the fluorescence changes with pH, the values of the pKa for the ground (9.9 +/- 0.2) and the excited state (7.7 +/- 0.2) for 5M were determined. From the fluorescence changes with beta-cyclodextrin or hydroxypropyl-beta-cyclodextrin, the association constants of M, 5MH [5-methoxy-3-(2-ammoniumethyl)indole] and 5M with the two hosts were determined. The values with beta-cyclodextrin were KAssoc5MH = (1.4 +/- 0.4) x 10(2) mol-1 dm3, KAssoc5M = (1.6 +/- 0.1) x 10(2) mol-1 dm3 and KAssocM = (1.1 +/- 0.2) x 10(2) mol-1 dm3, and with hydroxypropyl-beta-cyclodextrin KAssoc5MH = (1.1 +/- 0.3) x 10(2) mol-1 dm3, KAssoc5M = (2.5 +/- 0.1) x 10(2) mol-1 dm3 and KAssocM = (1.51 +/- 0.07) x 10(2) mol-1 dm3. The ratios of the fluorescence quantum yields for the bound and free substrate (phi b/phi f) were in the range 1.15-1.48. The detection limits under the optimum conditions were 0.381 +/- 0.001 ng cm-3 for the complex 5MH-hydroxypropyl-beta-cyclodextrin in water and 0.290 +/- 0.001 ng cm-3 for the complex M-hydroxypropyl-beta-cyclodextrin in water with 5% of methanol. The recovery of melatonin from pharmaceutical preparations was 98-103% with an RSD of 2%. The recovery from rat pineals was also good. The method is direct, simple and accurate.

Cyclodextrin enhanced fluorimetric method for the determination of tryptamine.

The effect of native cyclodextrins (alpha-, beta- or gamma- with six, seven or eight glucose units, respectively), hydroxypropyl-beta-cyclodextrin, beta-cyclodextrin solubilized in urea, soluble starch and glucose in water solution on the fluorescence behaviour of tryptamine [3-(2-aminoethyl)indole] (T) was determined. In addition, the effect of methanol and propanol with and without beta-cyclodextrin or hydroxypropyl-beta-cyclodextrin was ascertained. From the fluorescence changes with pH and with beta-cyclodextrin or hydroxypropyl-beta-cyclodextrin, the values of the pKa of the ground and excited states and the association constants of T and TH [3-(2-ammoniumethyl)indole] with the two hosts were determined. The values are pKa = 9.5 +/- 0.2 and pKa* = 8.4 +/- 0.2; KAssocTH = (1.6 +/- 0.3) x 10(2) mol-1 dm3 and KAssocT = (2.8 +/- 0.3) x 10(2) mol-1 dm3 with beta-cyclodextrin, KAssocTH = (1.8 +/- 0.5) x 10(2) mol-1 dm3 and KAssocT = (4.9 +/- 0.9) x 10(2) mol-1 dm3 with hydroxypropyl-beta-cyclodextrin. The ratio of the fluorescence quantum yields for the bound and free substrate (phi b/phi f) were in the range 1.25-1.33. The detection limit for the better conditions where the host-guest interactions produce fluorescence enhancement was 0.454 +/- 0.002 ng ml-1 for the complex T-hydroxypropyl-beta-cyclodextrin in water. The method is simpler than others reported previously.

Pérdida plasmática en prótesis vasculares en cirugía cardiovascular pediátrica / Plasmatic fluid leakage through vascular grafts used lin pediatric cardiovascular surgery

Cinco niños con cardiopatías congénitas cianóticas (CCC) complejas fueron sometidos a cirugías paliativas con derivaciones sistémico-pulmonares del tipo Blalock-taussig, modificadas por el uso de prótesis vasculares de politetrafluoretilo (PTFE). Estas , una vez colocadas, comenzaron a perder líquido plasmático a través de su pared.En el cuarto . la pérdida cedió espontáneamente con el correr de las horas y en el quinto se adoptaron frente a cada situación. Se sugiere una serie de cuidados para las prótesis y se realizan advertencias sobre el manejo adecuado de esta peligrosa complicación

Pérdida plasmática en prótesis vasculares en cirugía cardiovascular pediátrica / Plasmatic fluid leakage through vascular grafts used lin pediatric cardiovascular surgery

Cinco niños con cardiopatías congénitas cianóticas (CCC) complejas fueron sometidos a cirugías paliativas con derivaciones sistémico-pulmonares del tipo Blalock-taussig, modificadas por el uso de prótesis vasculares de politetrafluoretilo (PTFE). Estas , una vez colocadas, comenzaron a perder líquido plasmático a través de su pared.En el cuarto . la pérdida cedió espontáneamente con el correr de las horas y en el quinto se adoptaron frente a cada situación. Se sugiere una serie de cuidados para las prótesis y se realizan advertencias sobre el manejo adecuado de esta peligrosa complicación

Plicatura diafragmática en la parálisis frénica unilateral luego de cirugía cardíaca / Diaphragmatic plication in phrenic nerve paralysis ter cardiac surgery

Presentamos cinco niños con parálisis unilateral permanente luego de operaciones por cardiopatías congénitas. Cuatro de ellos fueron tratados con plicatura diafragmática y uno con kinesioterapia. En dos niños menores de 3 meses la plicatura diafragmática precoz permitió acortar la asistencia ventilatoria. En dos niños mayores se realizó la plicatura del diafragma en el momento de la corrección de la cardiopatía, con desaparición posterior de los síntomas respiratorios. La plicatura diafragmática precoz en lactantes ofrece excelentes resultados. En niños mayores, aunque la parálisis frénica es bien tolerada, la plicatura hace desaparecer completamente los síntomas respiratorios

Plicatura diafragmática en la parálisis frénica unilateral luego de cirugía cardíaca / Diaphragmatic plication in phrenic nerve paralysis ter cardiac surgery

Presentamos cinco niños con parálisis unilateral permanente luego de operaciones por cardiopatías congénitas. Cuatro de ellos fueron tratados con plicatura diafragmática y uno con kinesioterapia. En dos niños menores de 3 meses la plicatura diafragmática precoz permitió acortar la asistencia ventilatoria. En dos niños mayores se realizó la plicatura del diafragma en el momento de la corrección de la cardiopatía, con desaparición posterior de los síntomas respiratorios. La plicatura diafragmática precoz en lactantes ofrece excelentes resultados. En niños mayores, aunque la parálisis frénica es bien tolerada, la plicatura hace desaparecer completamente los síntomas respiratorios