Analysis of the denitrification pathway and greenhouse gases emissions in Bradyrhizobium sp. strains used as biofertilizers in South America.

AIMS: Greenhouse gases are considered as potential atmospheric pollutants, with agriculture being one of the main emission sources. The practice of inoculating soybean seeds with Bradyrhizobium sp. might contribute to nitrous oxide (N2 O) emissions. We analysed this capacity in five of the most used strains of Bradyrhizobium sp. in South America. METHODS AND RESULTS: We analysed the denitrification pathway and N2 O production by Bradyrhizobium japonicum E109 and CPAC15, Bradyrhizobium diazoefficiens CPAC7 and B. elkanii SEMIA 587 and SEMIA 5019, both in free-living conditions and in symbiosis with soybean. The in silico analysis indicated the absence of nosZ genes in B. japonicum and the presence of all denitrification genes in B. diazoefficiens strains, as well as the absence of nirK, norC and nosZ genes in B. elkanii. The in planta analysis confirmed N2 O production under saprophytic conditions or symbiosis with soybean root nodules. In the case of symbiosis, up to 26.1 and 18.4 times higher in plants inoculated with SEMIA5019 and E109, respectively, than in those inoculated with USDA110. CONCLUSIONS: The strains E109, SEMIA 5019, CPAC15 and SEMIA 587 showed the highest N2 O production both as free-living cells and in symbiotic conditions in comparison with USDA110 and CPAC7, which do have the nosZ gene. Although norC and nosZ could not be identified in silico or in vitro in SEMIA 587 and SEMIA 5019, these strains showed the capacity to produce N2 O in our experimental conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report to analyse and confirm the incomplete denitrification capacity and N2 O production in four of the five most used strains of Bradyrhizobium sp. for soybean inoculation in South America.

Bacteriemia por Ochrobactrum anthropi en paciente en hemodiálisis por catéter tunelizado permanente: Caso clínico / Catheter associated bacteremia caused by Ochrobactrum anthropi in a patient on hemodialysis: Report of one case

Ochrobactrum anthropi is a rare pathogen in humans that is usually related to infections in inmunocompromised patients or people with indwelling medical devices. There are very few reported cases of O. anthropi bacteremia in patients on hemodialysis. We report a 19-year-old female on hemodialysis through a jugular catheter, with fever and malaise lasting one month. The catheter was withdrawn and Ochrobactrum anthropi was isolated from it and from blood cultures. The patient was successfully treated with levofloxacin.

Estudio histológico del tracto digestivo del neón cardenal paracheirodon axelrodi (Characidae) / Histological study of digestive tract of the neón cardenal paracheirodon axelrodi (Characidae)

Paracheirodon axelrodi es el pez ornamental que más se exporta en Colombia. Sin embargo, se desconocen varios aspectos de su biología básica. Se estudió la histología del tracto digestivo. Se sacrificaron 15 ejemplares (MS 222, 0,5 g/L), fijados en formaldehído al 4 por ciento y decalcificados con ácido nítrico 7 por ciento. Se siguió el procedimiento para H&E. El tracto digestivo de P. axelrodi presentó cuatro capas constitutivas: mucosa, submucosa, muscular y serosa. La mucosa de la boca presentó un epitelio escamoso estratificado no queratinizado con células caliciformes y sin botones gustativos, una submucosa de tejido conectivo laxo y una capa de músculo estriado esquelético. Los dientes son cónicos y abundantes. La capa serosa a lo largo del tracto digestivo es delgada compuesta de tejido conectivo laxo. La capa mucosa, submucosa y muscular del esófago posee la misma conformación tisular de la boca, sin embargo, la capa muscular presenta dos orientaciones. La mucosa del estómago está compuesta por epitelio cilíndrico simple con glándulas gástricas, submucosa de tejido conectivo laxo y una capa de músculo liso en dos orientaciones. Las capas del intestino exhi-bieron una composición tisular similar a la del estómago, sin glándulas gástricas. La mucosa presentó células caliciformes especialmente hacia la región posterior y un aumento en la longitud de los pliegues intestinales. La conformación tisular y morfológica del tracto digestivo de P. axelrodi lo ubica como un pez de hábitos alimenticios carnívoros pero de pequeñas presas.

Cardinal neon, Paracheirodon axelrodi is the most exported ornamental fish in Colombia. However, many aspects of its biology are unknown. A histological study of the digestive tract was carried out and 15 specimens were sacrificed with MS 222, 0.5 g/L, fixed in 4 percent formaldehyde and decalcified with 7 percent nitric acid. H&E technique was followed. P. axelrodi digestive tract showed four constitutive layers: mucosae, submucosae, muscular, and serosa. Mouth mucosae presents a stratified nonkeratinized squamous epithelium with many goblet cells, and no taste buds, submucosae with areolar connective tissue, and skeletal muscular layer. Teeth were conical and abundant. Along the whole intestinal tract the serous was a very thin connective tissue layer. Esophagus mucosae, submucosae, and muscular layer were similar to those of the mouth. However, muscular layer presented two layers in different orientations. Stomach mucosae were made of simple cylindrical epithelium with gastric glands. Submucosa did present areolar connective tissue, and muscular layer exhibited smooth muscle in two different orientations. The intestinal layers were similar to those of the stomach, but without gastric glands. Mucosae presented goblet cells especially at the posterior region. Intestinal folds were also observed. Tisular and morphological structure of P. axelrodi digestive tract suggests a small prey carnivorous fish.

[Catheter associated bacteremia caused by Ochrobactrum anthropi in a patient on hemodialysis: report of one case]. / Bacteriemia por Ochrobactrum anthropi en paciente en hemodiálisis por catéter tunelizado permanente: caso clínico.

Ochrobactrum anthropi is a rare pathogen in humans that is usually related to infections in immunocompromised patients or people with indwelling medical devices. There are very few reported cases of O. anthropi bacteremia in patients on hemodialysis. We report a 19-year-old female on hemodialysis through a jugular catheter, with fever and malaise lasting one month. The catheter was withdrawn and Ochrobactrum anthropi was isolated from it and from blood cultures. The patient was successfully treated with levofloxacin.

Determination of cocaine and benzoylecgonine by direct injection of human urine into a column-switching liquid chromatography system with diode-array detection.

A method for the determination of cocaine (COC) and benzoylecgonine (BZE) in human urine using a column-switching liquid chromatography system is reported. A homemade precolumn (20 mm x 4.6 mm i.d.) dry-packed with Alltech ODS-C18 (35-750 microm) was employed as an extraction precolumn in order to extract and concentrate the COC and BZE from the human urine sample. The analytes were continuously transferred to the analytical column (Spherisorb-C8, 250 mm x 4.6 mm i.d.; dp = 5 microm) by means of the switching arrangement in the backflush mode. Detection was carried out at 235 nm in a UV-diode array detector. The validation of the method revealed analytes quantitative recoveries (96-102%) at three concentrations in the range from 0.25 to 4.00 and from 0.5 to 12.0 microg/mL for COC and BZE, respectively. These values demonstrate the excellent extraction efficiency of the precolumn. The detection limits for COC and BZE at a signal-to-noise ratio of 3 were 0.08 and 0.15 microg/mL when a sample volume of 50 microL was injected. The overlap of sample preparation, analysis and recondition of the precolumn increases the sample throughput to four samples per hour. The proposed method has been applied to the determination of COC and BZE in human urine samples from 73 suspecting drug addicts. Urine concentrations of 1.0-118.10 microg of BZE/mL and 0.1-41.0 microg of COC/mL were found.

HPLC determination of Vitamin D(3) and its metabolite in human plasma with on-line sample cleanup.

A HPLC method with automated column switching and UV-diode array detection is described for the simultaneous determination of Vitamin D(3) and 25-hydroxyvitamin D(3) (25-OH-D(3)) in a sample of human plasma. The system uses a BioTrap precolumn for the on-line sample cleanup. A sample of 1ml of human plasma was treated with 2ml of a mixture of ethanol-acetonitrile (2:1 (v/v)). Following centrifugation, the supernatant was evaporated to dryness under a stream of dry and pure nitrogen. The residue was reconstituted in 250muL of a solution of methanol 5mmoll(-1) phosphate buffer, pH 6.5 (4:1 (v/v)), and a 200mul aliquot of this solution was injected onto the BioTrap precolumn. After washing during 5min with a mobile phase constituted by a solution of 6% acetonitrile in 5mmoll(-1) phosphate buffer, pH 6.5 (extraction mobile phase), the retained analytes were then transferred to the analytical column in the backflush mode. The analytical separation was then performed by reverse-phase chromatography in the gradient elution mode with the solvents A and B (Solvent A: acetonitrile-phosphate buffer 5mmoll(-1), pH 6.5; 20:80 (v/v); solvent B: methanol-acetonitrile-tetrahydrofuran, 65:20:15 (v/v)). The compounds of interest were detected at 265nm. The method was linear in the range 3.0-32.0ngml(-1) with a limit of quantification of 3.0ngml(-1). Quantitative recoveries from spiked plasma samples were between 91.0 and 98.0%. In all cases, the coefficient of variation (CV) of the intra-day and inter-day-assay precision was

Column-switching high-performance liquid chromatographic analysis of carbamazepine and its principal metabolite in human plasma with direct sample injection using an alkyl-diol silica (ADS) precolumn.

In this paper, the on-line coupling of solid-phase extraction, based on a restricted-access support with high-performance reverse phase chromatography for the analysis of carbamazepine (CBZ) and carbamazepine-10,11-epoxide (CBZ-E) in human plasma samples is described. A precolumn packed with 25 mum C(18) alkyl-diol support is used for direct plasma injection. Using column-switching techniques, the analytes were enriched on the precolumn by a 5 mM phosphate buffer (pH 7) with 2% of methanol solution at a flow-rate of 0.8 ml min(-1), while proteins and endogenous hydrophilic substances in plasma were washed off to waste. The enriched analytes were then back-flushed onto the analytical C(18) column, separated by a mixture of 10 mM phosphate buffer (pH 7) acetonitrile (70:30 v/v) solution at a flow-rate of 1.0 ml min(-1) and detected by the ultraviolet absorbance set at 212 and 285 nm and without transfer loss. Linear calibration graphs were obtained for sample injection volumes of 50 (0.2-4.0 of mug of CBZ ml(-1) and 0.1-5.0 mug of CBZ-E ml(-1), respectively), and 20 mul (5.0-20.0 mug of CBZ ml(-1)); in either case the r-value was >0.9963. Recoveries from spiked plasma samples were quantitative for both analytes and the coefficients of variation were below 3.83%. The lowest samples concentrations that can be quantified with acceptable accuracy and precision was 0.2 mug CBZ ml(-1) and 0.1 mug CBZ-E ml(-1) when a sample volume of 50 mul was injected. Concentrations of 0.08 and 0.05 mug ml(-1) of CBZ and CBZ-E were considered the limit of detection for a signal-to-noise ratio of 3. Furthermore, the developed column-switching method was successfully applied to the determination of CBZ and CBZ-E in plasma samples of patients submitted to CBZ therapy.

[Myoclonic epilepsies in pediatrics]. / Epilepsias mioclónicas en pediatría.

INTRODUCTION: In our environment the frequency of epilepsy is 1.9% and in the central anti-epilepsy league (LICCE) of Santafé de Bogotá, Colombia, some 1,500 patients are attended each month (approximately 75 daily), of which an average of 7.2 consulted for the first time. DEVELOPMENT: This article about myoclonic epilepsy in paediatrics allows the clinician to have a general view of the patient who consults for the first time, facilitating his subsequent treatment. We emphasize the etiological classification of the first crises, seeking specifically to discover whether it is a disorder, a sequela, a syndrome or an isolated crisis. We present the basic definitions: classification according to physiology, anatomy, symptomatology (epileptic or nonepileptic), cryptogenetics (intermediate or polymorphic) and benign, severe or progressive. CONCLUSION: Finally we draw attention to the description of fifteen syndromes in which the clinical picture of progressive, myoclonic epilepsy is variable and the aetiology complicated.

[Juvenile myoclonic epilepsy]. / Epilepsia mioclónica juvenil.

Since juvenile myoclonic epilepsy (EMJ) and/or Janz syndrome is a primary syndrome which persists throughout life, there should be permanent behavioural hygiene and treatment to keep it under control. Suspension of treatment is nearly always followed by recurrence. Although some researchers report relapses of 75% on suspension of treatment, Janz (1995), cited by Dreifuss points out that this rises to 91% in patients who suspend treatment after two years with no crises. This is, to date, the highest documented level of relapses in epilepsy (5,6,12).

High sodium diet and Na+-stimulated ATPase activities in basolateral plasma membranes from rat kidney proximal tubular cells.

The ouabain-insensitive, Na+-stimulated ATPase activity of kidney proximal tubular cells from rats fed a high Na+ diet for 4 months was increased approximately 70% when compared with control (normal diet) rats. The higher ATPase activity was not due to a change in the affinity of the system toward ATP, Mg2+ or Na+. This increase in Na+-ATPase activity may be due to either a higher number of pumps or to a higher turnover rate of the enzyme or both. The ouabain-sensitive, Na+, K+-stimulated ATPase activity, on the other hand, did not change with the high sodium diet. These results can be taken as evidence that the Na+,K+-ATPase and the Na+-ATPase of basolateral plasma membranes of proximal tubular cells from rat kidney are two different entities.

Effect of a high NaCl diet on the active mechanisms of Na+ extrusion in rat kidney.

Healthy male rats were exposed to a chronic ingesta of an isotonic NaCl solution during a period of four months. Two different preparations were utilized to study the effect of this treatment on the active mechanisms of Na+ reabsorption of kidney proximal tubular cells: outermost kidney cortex slices (rich in proximal tubules) and inside-out basolateral plasma membrane vesicles prepared from the same tissue. It was found that the activity of the ouabain-insensitive, Na-pump of basolateral plasma membranes of kidney proximal tubular cells was increased in about 70%, whereas the ouabain-sensitive, Na,K-pump activity did not change with the experimental treatment. These results represent a strong support to the two Na-pump's hypothesis since the treatment affected the Na-pump differentially without affecting the Na,K-pump.

Fate of experimental allogeneically transplanted fetal adrenal glands in nonimmunosuppressed adrenalectomized adult rats.

Long-term survival of allogeneic vascularized fetal adrenal transplants has been demonstrated in adrenalectomized rats. Significant less mortality occurred after adrenalectomy in animals receiving multiple allogeneic fetal transplants compared to nontransplanted rats.