Evaluation of the reproducibility of the Tronzo classification for intertrochanteric fractures of the femur in an orthopedic service of a Hospital in Ibagué, Colombia / Evaluación de la reproducibilidad de la clasificación de Tronzo para fracturas intertrocantéricas de fémur en un servicio de ortopedia de un Hospital de Ibague, Colombia

Introduction: Hip fractures are a pathology of traumatic origin that generates a high impact on public health. The objective is to evaluate the interobserver reproducibility of the Tronzo classification for intertrochanteric fractures. Methods: Observational, analytical and retrospective study carried out in Ibagué - Colombia, 48 hip radiographs were analyzed, classified by 10 observed among specialists and training personnel, using the Tronzo classification. Interobserver reproducibility is assessed using the kappa concordance coefficient. Results: Among all those observed in the study, there is greater agreement in the identification of intertrochanteric fractures of lesser and greater severity (Tronzo I and V), the main exponents of this agreement are the most experienced staff, the staff in training, with intermediate experience they agree when identifying those of intermediate severity and for those with less experience the concordance becomes evident when evaluating the intermediate grades. Conclusion: The concordance increases with the experience for the identification of the types with high complexity. This classification is not suitable for clinical practice, another system is necessary for this type of fracture in clinical conduct.

Introducción: Las fracturas de cadera son una patología de origen traumático que genera un alto impacto en la salud pública. El objetivo es evaluar la reproducibilidad interobservador de la clasificación de Tronzo para fracturas intertrocantéricas. Métodos: Estudio observacional, analítico y retrospectivo realizado en Ibagué ­ Colombia, se analizaron 48 radiografías de cadera, clasificadas por 10 observado entre especialistas y personal en formación, utilizando la clasificación de Tronzo. La reproducibilidad interobservador se evalúa mediante el coeficiente de concordancia kappa. Resultados: Entre todos los observados del estudio existe mayor acuerdo en la identificación de fracturas intertrocantéricas de menor y mayor gravedad (Tronzo I y V), los principales exponentes de este acuerdo son el personal de mayor experiencia, el personal en formación, con experiencia intermedia están de acuerdo al identificar a los de gravedad intermedia y para los que tienen menos experiencia la concordancia se hace evidente a la hora de evaluar los grados intermedios. Conclusión: La concordancia aumenta con la experiencia para la identificación de los tipos con alta complejidad. No es adecuado para la práctica clínica esta clasificación, es necesario otro sistema para este tipo de fracturas en las conductas clínicas.

Prevalencia de sarcopenia en adultos mayores de dos hogares geriátricos de Pereira, Colombia Prevalence of sarcopenia in older adults in t / Prevalence of sarcopenia in older adults in two retirement homes in Pereira, Colombia

Introducción: La sarcopenia es un factor de riesgo para morbilidad, mortalidad y discapacidad en adultos mayores, por lo que su manejo es prioridad en geriatría. El objetivo de este artículo, consiste en caracterizar una población de adultos mayores de dos hogares geriátricos y establecer la prevalencia de sarcopenia y el grado de dependencia. Métodos: Estudio de corte transversal desarrollado en la ciudad de Pereira-Colombia. Se incluyó a una población de 72 adultos desde los 65 hasta los 98 años, usando muestreo probabilístico. Se determinó la sarcopenia por medio de los Criterios del Consenso Europeo sobre Definición y Diagnóstico de Sarcopenia; evaluándose la fuerza de prensión, índice de masa muscular esquelética, en caso de presentarse sarcopenia, la severidad de esta junto a la velocidad de marcha, y el grado de dependencia según la escala de Barthel. Resultados: Participaron finalmente 57 personas. El 68,4% (n=39) eran mujeres. La mediana de la edad fue de 83 años. El 2% no presentó sarcopenia, 9% presentaban sospecha de sarcopenia, 28% tenían sarcopenia confirmada y 61% sarcopenia grave. Según la escala de Barthel, el 31,5% eran independientes, 45,6% tenían dependencia leve, 15,8% moderada, 5,3% severa y 1,8% total. Conclusiones: La prevalencia de sarcopenia en los hogares geriátricos de Pereira es mayor en comparación a la reportada en la literatura. Del mismo modo, encontrarse en un hogar geriátrico privado no garantiza una mejor condición física y/o calidad de vida.

Introduction: Is a risk factor for morbidity, mortality and disability in older adults, so its management is a priority in geriatrics. The aim of this article is to characterize a population of older adults from two geriatric homes and to establish the prevalence of sarcopenia and the degree of dependence. Methods: Cross-sectional study developed in the city of Pereira-Colombia. A population of 72 adults from 65 to 98 years of age was included, using probability sampling. Sarcopenia was determined by means of the Criteria of the European Consensus on Definition and Diagnosis of Sarcopenia, evaluating grip strength, skeletal muscle mass index, in case of sarcopenia, the severity of sarcopenia together with walking speed, and the degree of dependence according to the Barthel scale. Results: 57 people participated. A total of 68.4% (n=39) were women. The median age was 83 years. Two percent had no sarcopenia, 9% had suspected sarcopenia, 28% had confirmed sarcopenia and 61% had severe sarcopenia. According to the Barthel scale, 31.5% were independent, 45.6% had mild, 15.8% moderate, 5.3% severe and 1.8% total dependence. Conclusions: The prevalence of sarcopenia in nursing homes in Pereira is higher compared to that reported in the literature. Similarly, being in a private nursing home does not guarantee a better physical condition and/or quality of life

Validación de los criterios predictivos de alto riesgo para coledocolitiasis de la Sociedad Americana de Endoscopia Gastrointestinal, 2010: Experiencia de un centro del caribe colombiano / Validation of the predictive criteria of high risk for choledocholithiasis of the american society for Gastrointestinal Endoscopy, 2010: experience of a Colombian Caribbean Center

Introducción: La colangiopancreatografía retrógrada endoscópica (CPRE) se ha convertido en el estándar de oro para el diagnóstico y tratamiento de la coledocolitiasis. La Sociedad Americana de Endoscopia Gastrointestinal (ASGE) propuso en 2010 estratificar a los pacientes en 3 niveles de riesgo; sin embargo, los estudios han encontrado resultados controvertidos sobre los parámetros predictivos de estos criterios diagnósticos. El objetivo de este estudio consiste en determinar el desempeño de los criterios predictivos de alto riesgo de la ASGE 2010 en el diagnóstico de coledocolitiasis en una población del Caribe colombiano. Métodos: Estudio transversal retrospectivo, en el que se incluyeron pacientes con sospecha de coledocolitiasis, y que fueron llevados a evaluación por CPRE, cumpliendo los criterios propuestos por la ASGE de alta probabilidad. El resultado obtenido se comparó con la presencia de coledocolitiasis en la CPRE, a partir de la cual se estimaron los valores y los intervalos de confianza del 95% para la sensibilidad, la especificidad, el valor predictivo positivo y negativo, y la razón de probabilidad positiva y negativa. Resultados: En este estudio se incluyeron los datos de 118 pacientes. La edad media de los pacientes era de 46 años (RIQ= 31; 17- 89); el 78% (n= 92) eran mujeres. El 65,3% (n= 77) eran mayores de 55 años. El resultado de la CPRE fue positivo en el 81,4% (n= 96) de los pacientes. La presencia de un perfil hepático alterado (90%) resultó ser la prueba más sensible, la colangitis clínica (86%) la más específica, la presencia de litiasis ductal por US (85%) fue la prueba con mayor valor predictivo positivo, y la presencia de litiasis ductal por US (35%) fue la prueba con mayor valor predictivo negativo. Conclusión: Los parámetros predictivos de los criterios de la ASGE 2010 para el diagnóstico de coledocolitiasis muestran variabilidad con respecto al rendimiento propuesto en las guías.

Introduction: Endoscopic retrograde cholangiopancreatography (ERCP) has become the gold standard for diagnosis and treatment of choledocholithiasis. The American Society for Gastrointestinal Endoscopy (ASGE) in 2010 proposed stratifying patients into 3 risk levels; however, studies have found controversial results about the predictive parameters of these diagnostic criteria. The objective of this study is to determine the performance of the high-risk predictive criteria of the ASGE 2010 in the diagnosis of choledocholithiasis in a Colombian Caribbean population. Methods: Retrospective cross-sectional study, which included patients with suspected choledocholithiasis, and who were taken for evaluation by ERCP, meeting the criteria proposed by the ASGE of high probability. The result obtained was compared with the presence of choledocholithiasis on ERCP, from which values and 95% confidence intervals were estimated for sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ratio. Results: A total of 118 patient data were included in this study. The median age of the patients was 46 years (IQR= 31; 17- 89); 78% (n= 92) were female. 65.3% (n= 77) were older than 55 years. The ERCP result was positive in 81.4% (n= 96) of the patients. The presence of an altered liver profile (90%) was found to be the most sensitive test, clinical cholangitis (86%) the most specific, the presence of duct lithiasis by US (85%) was the test with the highest positive predictive value, and the presence of duct lithiasis by US (35%) was the test with the highest negative predictive value. Conclusions: The predictive parameters of the ASGE 2010 criteria for the diagnosis of choledocholithiasis show variability with respect to the performance proposed in the guidelines.

Determinantes del peso al nacer en hijos de mujeres venezolanas migrantes irregulares en Barranquilla y Riohacha / Determinants of birth weight among children of irregular migrant Venezuelan women in Barranquilla and Riohacha

RESUMEN Objetivo Describir los factores determinantes del peso al nacer en los hijos de mujeres venezolanas en condición migratoria irregular durante la gestación, en Barranquilla y Riohacha, en el periodo 2018-2019. Materiales y Métodos Se realizó un estudio descriptivo longitudinal de fuente secundaria, con base hospitalaria y comunitaria. Se incluyeron los binomios madre-hijo de mujeres venezolanas en condición irregular cuyo parto se presentó en Barranquilla y Riohacha entre julio de 2018 y diciembre de 2019 (n=563). Resultados Se encontró asociación estadísticamente significativa entre el número de controles prenatales y el bajo peso al nacer. Las odds de nacer con bajo peso entre quienes no tuvieron controles fueron de 4,0 veces en relación con quienes cumplieron con al menos 4 controles durante el embarazo (OR=4,0; IC 95% 1,5 - 10,4). Conclusiones Se encontró que la probabilidad de bajo peso al nacer en los recién nacidos de aquellas madres que no se realizaron controles prenatales es superior en un 82,7% a la de los hijos de las madres que tuvieron cuatro controles prenatales o más.(AU)

ABSTRACT Objective To describe the determinants of birth weight in the children of Venezuelan women in irregular migration status during pregnancy, in Barranquilla and Riohacha, between 2018 and 2019. Materials and Methods We carried out a longitudinal and descriptive study of secondary source, with a hospital and community basis. We included mother-child pairs of Venezuelan women in an irregular condition whose delivery occurred in Barranquilla and Riohacha between July 2018 and December 2019 (n=563). Results: We found a significative association between the number of prenatal care and low birth weight. The odds of being born with low birth weight among those who had no controls was 4.0 times in relation to those who met at least 4 controls during pregnancy (OR = 4.0, 95% CI 1.5 - 10.4). Conclusions The probability of low birth weight in the newborns of those mothers who did not have prenatal controls was 82.7% higher compared to the children of mothers who had four or more prenatal cares.(AU)

[Determinants of birth weight among children of irregular migrant Venezuelan women in Barranquilla and Riohacha]. / Determinantes del peso al nacer en hijos de mujeres venezolanas migrantes irregulares en Barranquilla y Riohacha.

OBJECTIVE: To describe the determinants of birth weight in the children of Venezuelan women in irregular migration status during pregnancy, in Barranquilla and Riohacha, between 2018 and 2019. MATERIALS AND METHODS: We carried out a longitudinal and descriptive study of secondary source, with a hospital and community basis. We included mother-child pairs of Venezuelan women in an irregular condition whose delivery occurred in Barranquilla and Riohacha between July 2018 and December 2019 (n=563). Results: We found a significative association between the number of prenatal care and low birth weight. The odds of being born with low birth weight among those who had no controls was 4.0 times in relation to those who met at least 4 controls during pregnancy (OR = 4.0, 95% CI 1.5 - 10.4). CONCLUSIONS: The probability of low birth weight in the newborns of those mothers who did not have prenatal controls was 82.7% higher compared to the children of mothers who had four or more prenatal cares.

OBJETIVO: Describir los factores determinantes del peso al nacer en los hijos de mujeres venezolanas en condición migratoria irregular durante la gestación, en Barranquilla y Riohacha, en el periodo 2018-2019. MATERIALES Y MÉTODOS: Se realizó un estudio descriptivo longitudinal de fuente secundaria, con base hospitalaria y comunitaria. Se incluyeron los binomios madre-hijo de mujeres venezolanas en condición irregular cuyo parto se presentó en Barranquilla y Riohacha entre julio de 2018 y diciembre de 2019 (n=563). RESULTADOS: Se encontró asociación estadísticamente significativa entre el número de controles prenatales y el bajo peso al nacer. Las odds de nacer con bajo peso entre quienes no tuvieron controles fueron de 4,0 veces en relación con quienes cumplieron con al menos 4 controles durante el embarazo (OR=4,0; IC 95% 1,5 - 10,4). CONCLUSIONES: Se encontró que la probabilidad de bajo peso al nacer en los recién nacidos de aquellas madres que no se realizaron controles prenatales es superior en un 82,7% a la de los hijos de las madres que tuvieron cuatro controles prenatales o más.

[Thrombotic thrombocytopenic purpura and tuberculosis. A rare association]. / Púrpura trombótica trombocitopénica y tuberculosis. Una rara asociación.

Thrombocytopenic thrombotic purpura (TTP) is a thrombotic microangiopathy associated with hematopoietic stem cells transplantation, pregnancy, puerperium, drugs, bloody diarrhea, a heterogeneous group of illnesses, such as malignant hypertension, autoimmune and neoplastic diseases, infections, and an idiopathic group that includes the pathologies that don't apply for the preceding clinical categories. Tuberculosis is an illness of intermediate incidence in Argentina, with increased frequency in high-risk groups. In this article, we present the case of a 60 years old male patient, with abdominal pain, cough and nocturnal sweating. He was diagnosed as having thrombocytopenia, and a few days later, microangiopathic anemia and TTP. Further examinations led TBC diagnosis based on: 1) acid fast bacillus (+++) for Ziehl Neelsen stain in bronco alveolar lavage, 2) laryngeal lesion and 3) ileocecal valve lesion. We report this case, because TBC has rarely been associated with TTP in medical literature.

Púrpura trombótica trombocitopénica y tuberculosis: Una rara asociación / Thrombotic thrombocytopenic purpura and tuberculosis. A rare association

La púrpura trombótica trombocitopénica (PTT) es una microangiopatía trombótica asociada a cuadros de trasplante de células madre hematopoyéticas, embarazo y posparto, al uso de ciertas drogas, diarrea sanguinolenta, a un grupo heterogéneo de trastornos como enfermedades autoinmunes, hipertensión maligna, enfermedades neoplásicas, diversas infecciones y un grupo llamado idiopático, donde se incluyen aquellos en quienes no se cumplieron los criterios de las categorías clínicas anteriores. La tuberculosis (TBC) es una enfermedad de incidencia intermedia en Argentina, más frecuente en determinados grupos poblacionales. Presentamos el caso de un varón de 60 años que consulta por dolor abdominal, tos y sudoración nocturna; se detectó primero trombocitopenia y luego de algunos días anemia microangiopática, lo que llevó al diagnóstico de PTT. Posteriormente, al continuar con la evaluación, se diagnosticó TBC por: 1) baciloscopia positiva para bacilos ácido-alcohol resistentes (+++) por técnica de Ziehl Neelsen en lavado broncoalveolar, 2) lesiones en laringe y 3) lesiones en válvula ileocecal. La TBC ha sido pocas veces asociada con la PTT en la literatura, razón por la cual presentamos este caso.

Thrombocytopenic thrombotic purpura (TTP) is a thrombotic microangiopathy associated with hematopoietic stem cells transplantation, pregnancy, puerperium, drugs, bloody diarrhea, a heterogeneous group of illnesses, such as malignant hypertension, autoimmune and neoplastic diseases, infections, and an idiopathic group that includes the pathologies that don’t apply for the preceding clinical categories. Tuberculosis is an illness of intermediate incidence in Argentina, with increased frequency in high-risk groups. In this article, we present the case of a 60 years old male patient, with abdominal pain, cough and nocturnal sweating. He was diagnosed as having thrombocytopenia, and a few days later, microangiopathic anemia and TTP. Further examinations led TBC diagnosis based on: 1) acid fast bacillus (+++) for Ziehl Neelsen stain in bronco alveolar lavage, 2) laryngeal lesion and 3) ileocecal valve lesion. We report this case, because TBC has rarely been associated with TTP in medical literature.

Disproportionation of O-methylhydroxylamine catalyzed by aquapentacyanoferrate(II).

The aquapentacyanoferrate(II) ion, [Fe(II)(CN)(5)H(2)O](3-), catalyzes the disproportionation reaction of O-methylhydroxylamine, NH(2)OCH(3), with stoichiometry 3NH(2)OCH(3) → NH(3) + N(2) + 3CH(3)OH. Kinetic and spectroscopic evidence support an initial N coordination of NH(2)OCH(3) to [Fe(II)(CN)(5)H(2)O](3-) followed by a homolytic scission leading to radicals [Fe(II)(CN)(5)(•)NH(2)](3-) (a precursor of Fe(III) centers and bound NH(3)) and free methoxyl, CH(3)O(•), thus establishing a radical path leading to N-methoxyamino ((•)NHOCH(3)) and 1,2-dimethoxyhydrazine, (NHOCH(3))(2). The latter species is moderately stable and proposed to be the precursor of N(2) and most of the generated CH(3)OH. Intermediate [Fe(III)(CN)(5)L](2-) complexes (L = NH(3), H(2)O) form dinuclear cyano-bridged mixed-valent species, affording a catalytic substitution of the L ligands promoted by [Fe(II)(CN)(5)L](3-). Free or bound NH(2)OCH(3) may act as reductants of [Fe(III)(CN)(5)L](2-), thus regenerating active sites. At increasing concentrations of NH(2)OCH(3) a coordinated diazene species emerges, [Fe(II)(CN)(5)N(2)H(2)](3-), which is consumed by the oxidizing CH(3)O(•), giving N(2) and CH(3)OH. Another side reaction forms [Fe(II)(CN)(5)N(O)CH(3)](3-), an intermediate containing the nitrosomethane ligand, which is further oxidized to the nitroprusside ion, [Fe(II)(CN)(5)NO](2-). The latter is a final oxidation product with a significant conversion of the initial [Fe(II)(CN)(5)H(2)O](3-) complex. The side reaction partially blocks the Fe(II)-aqua active site, though complete inhibition is not achieved because the radical path evolves faster than the formation rates of the Fe(II)-NO(+) bonds.

Composition and biological activity of essential oils from Labiatae against Nezara viridula (Hemiptera: Pentatomidae) soybean pest.

BACKGROUND: Plant essential oils have been recognised as an important natural source of insecticide. This study analysed the chemical constituents and bioactivity of essential oils that were isolated via hydrodistillation from Origanum vulgare L. (oregano) and Thymus vulgaris L. (thyme) against eggs, second instar and adults of Nezara viridula (L.). RESULTS: The major component of oregano was p-cymene, and, for thyme, thymol. The ovicidal activity was tested by topical application; the essential oil from thyme was more effective. The fumigant activity was evaluated in an enclosed chamber; the LC50 values for oregano were 26.8 and 285.6 µg mL(-1) for nymphs and adults respectively; for thyme they were 8.9 µg mL(-1) for nymphs and 219.2 µg mL(-1) for adults. To evaluate contact activity, a glass vial bioassay was used; the LC50 values for oregano were 1.7 and 169.2 µg cm(-2) for nymphs and adults respectively; for thyme they were 3.5 and 48.8 µg cm(-2) respectively. The LT50 analyses for contact and fumigant bioassays indicated that thyme was more toxic for nymphs and adults than oregano. Both oils produced repellency on nymphs and adults. CONCLUSION: These results showed that the essential oils from O. vulgare and T. vulgaris could be applicable to the management of N. viridula.

Biological activity of essential oils from Aloysia polystachya and Aloysia citriodora (Verbenaceae) against the soybean pest Nezara viridula (Hemiptera: Pentatomidae).

The objective of the current study was to determine the chemical constituents, ovicidal activity, fumigant, contact toxicity and repellent effects of essential oils isolated by hydrodistillation from Aloysia polystachya and A. citriodora against eggs and second instar nymphs of Nezara viridula. The major components were carvone (83.5%) for A. polystachya, and citronellal (51.3%) and sabinene (22.9%) for A. citriodora. The ovicidal activity of both oils was tested by topical application at different concentrations ranging from 1.2 to 12.5 microg/egg; all concentrations had a toxic effect. Data probit analysis showed that the LC50 value for A. polystachya was 2.3 microg/egg and for A. citriodora 1.9 microg/egg. The fumigant activity was evaluated in an enclosed chamber. The toxicity increased with concentration from 11 to 176 microg/mL air, and with exposure times from 1 to 48 h. The LC50 values for A. polystachya and A. citriodora were 29.9 and 13.5 microg/mL air 24 h after treatment, respectively. To evaluate contact activity a glass-vial bioassay was used. The toxicity increased with concentration from 2.8 to 45 microg/cm2 and with exposure time from 1 to 48 h. The LC50 for A. polystachya was 3.4 microg/cm2 and for A. citriodora 8.1 microg/cm2. The repellency bioassay demonstrated that both oils were active at the highest concentration (2.6 and 5.3 microg/mL air) and neutral at 1.3 microg/mL air. These results show that the essential oils from Aloysia polystachya and A. citriodora could be applicable to the management of populations of Nezara viridula.

Disproportionation of hydroxylamine by water-soluble iron(III) porphyrinate compounds.

The reactions of hydroxylamine (HA) with several water-soluble iron(III) porphyrinate compounds, namely iron(III) meso-tetrakis-(N-ethylpyridinium-2yl)-porphyrinate ([Fe(III)(TEPyP)](5+)), iron(III) meso-tetrakis-(4-sulphonatophenyl)-porphyrinate ([Fe(III)(TPPS)](3-)), and microperoxidase 11 ([Fe(III)(MP11)]) were studied for different [Fe(III)(Porph)]/[HA] ratios, under anaerobic conditions at neutral pH. Efficient catalytic processes leading to the disproportionation of HA by these iron(III) porphyrinates were evidenced for the first time. As a common feature, only N(2) and N(2)O were found as gaseous, nitrogen-containing oxidation products, while NH(3) was the unique reduced species detected. Different N(2)/N(2)O ratios obtained with these three porphyrinates strongly suggest distinctive mechanistic scenarios: while [Fe(III)(TEPyP)](5+) and [Fe(III)(MP11)] formed unknown steady-state porphyrinic intermediates in the presence of HA, [Fe(III)(TPPS)](3-) led to the well characterized soluble intermediate, [Fe(II)(TPPS)NO](4-). Free-radical formation was only evidenced for [Fe(III)(TEPyP)](5+), as a consequence of a metal centered reduction. We discuss the catalytic pathways of HA disproportionation on the basis of the distribution of gaseous products, free radicals formation, the nature of porphyrinic intermediates, the Fe(II)/Fe(III) redox potential, the coordinating capabilities of each complex, and the kinetic analysis. The absence of NO(2)(-) revealed either that no HAO-like activity was operative under our reaction conditions, or that NO(2)(-), if formed, was consumed in the reaction milieu.

Catalytic disproportionation of N-alkylhydroxylamines bound to pentacyanoferrates.

The substituted hydroxylamines, CH(3)N(H)OH (N-methylhydroxylamine) and (CH(3))(2)NOH (N,N-dimethylhydroxylamine), disproportionate catalytically to the corresponding alkylamines and oxidation products, only in the presence of [Fe(CN)(5)H(2)O](3-). Substitution kinetic measurements suggest an initial coordination step to Fe(ii). Two parallel N- and O-coordination modes are considered with the subsequent formation of Fe(iii), free aminyl (RNCH(3)) and nitroxide (RN(CH(3))O) radicals (R = H, CH(3)). With CH(3)N(H)OH, bound nitrosomethane, CH(3)NO, has been characterized by UV-visible and IR spectroscopies. The mechanism is discussed on the basis of common and differential features with respect to the disproportionation of hydroxylamine catalyzed by the same Fe-fragment.

The electrophilic reactions of pentacyanonitrosylferrate(II) with hydrazine and substituted derivatives. Catalytic reduction of nitrite and theoretical prediction of eta(1)-, eta(2)-N(2)O bound intermediates.

The electrophilic reactivity of the pentacyanonitrosylferrate(II) ion, [Fe(CN)(5)NO](2)(-), toward hydrazine (Hz) and substituted hydrazines (MeHz, 1,1-Me(2)Hz, and 1,2-Me(2)Hz) has been studied by means of stoichiometric and kinetic experiments (pH 6-10). The reaction of Hz led to N(2)O and NH(3), with similar paths for MeHz and 1,1-Me(2)Hz, which form the corresponding amines. A parallel path has been found for MeHz, leading to N(2)O, N(2), and MeOH. The reaction of 1,2-Me(2)Hz follows a different route, characterized by azomethane formation (MeNNMe), full reduction of nitrosyl to NH(3), and intermediate detection of [Fe(CN)(5)NO](3)(-). In the above reactions, [Fe(CN)(5)H(2)O](3)(-) was always a product, allowing the system to proceed catalytically for nitrite reduction, an issue relevant in relation to the behavior of the nitrite and nitric oxide reductase enzymes. The mechanism comprises initial reversible adduct formation through the binding of the nucleophile to the N-atom of nitrosyl. The adducts decompose through OH(-) attack giving the final products, without intermediate detection. Rate constants for the adduct-formation steps (k = 0.43 M(-)(1) s(-)(1), 25 degrees C for Hz) decrease with methylation by about an order of magnitude. Among the different systems studied, one-, two-, and multielectron reductions of bound NO(+) are analyzed comparatively, with consideration of the role of NO, HNO (nitroxyl), and hydroxylamine as bound intermediates. A DFT study (B3LYP) of the reaction profile allows one to characterize intermediates in the potential hypersurface. These are the initial adducts, as well as their decomposition products, the eta(1)- and eta(2)-linkage isomers of N(2)O.