Concentración preoperatoria de fibrinógeno plasmático como predictor de sangrado en artroplastía total de cadera / Preoperative concentration of plasma fibrinogen as a predictor of bleeding in total hip arthroplasty

Resumen: Introducción: La artroplastía total de cadera tiene popularidad debido al éxito en el tratamiento de coxartrosis; son procedimientos asociados a la pérdida de sangre. Un sangrado importante provoca complicaciones como aumento en días de estancia intrahospitalaria, mayor costo de la enfermedad, exponiendo al paciente a complicaciones asociadas a transfusión sanguínea. El objetivo del estudio es investigar asociación entre concentración de fibrinógeno plasmático preoperatorio con sagrado transquirúrgico y determinar el nivel de corte de fibrinógeno para presentar mayor sangrado transquirúrgico. Material y métodos: Estudio retrospectivo, observacional, analítico, de Junio a Diciembre de 2020, incluyendo 227 pacientes con coxartrosis IV de la escala de Kellgren y Lawrence sometidos a artroplastía total primaria de cadera, derechohabientes, mayores de 18 años, en ausencia de enfermedades hepáticas o hematológicas y antecedente de sangrado quirúrgico importante. Resultados: El valor promedio de hemoglobina preoperatoria fue 14.6 ± 1.3 g/dl, posterior a cirugía (48 horas) 10.5 ± 1.4 g/dl; observando descenso de 4.1 ± 1.2 g/dl (p ≤ 0.0001). Valor promedio del hematocrito prequirúrgico 43% [41-45], posterior al procedimiento 32% [29-35]; se observó descenso de 11% [8-14] (p ≤ 0.0001); 98 pacientes presentaron sangrado transquirúrgico ≥ 300 ml; 129 tuvieron sangrado ≤ 300 ml; 61.2% de pacientes con sangrado mayor de 300 ml mostraron valores de fibrinógeno debajo del punto de corte (388 mg/dl). Conclusión: En pacientes postoperados los niveles preoperatorios de fibrinógeno ≤ 388 mg/dl y edad ≥ 58 años se asociaron al aumento en el riesgo del OR = 0.18 (IC 95% 0.10-0.32) de presentar sangrado transquirúrgico ≥ 300 ml, con descenso de la Hb de 4.1 ± 1.2 g/dl (p = 0.0001) y Hto de 11% [8-14] (p = 0.0001) entre el preoperatorio y el postoperatorio en 48 horas.

Abstract: Introduction: Total hip arthroplasty is popular for its success in treating coxarthrosis, its associated with substantial blood loss. Significant bleeding causes complications such as increase in hospitalization days, higher costs, exposing the patient to complications associated with blood transfusion. The aim of the study is to investigate the association between preoperative plasma fibrinogen concentration and trans-surgical bleeding and determine fibrinogen level cut-off to present greater trans-surgical bleeding. Material and methods: Retrospective, observational, analytical study, from June to December 2020, including 227 patients with Kellgren and Lawrence scale IV coxarthrosis undergoing primary total hip arthroplasty, beneficiaries, older than 18 years, without liver or hematological diseases, and history of significant surgical bleeding. Results: Mean preoperative hemoglobin value was 14.6 ± 1.3 g/dl, after surgery (48 hours) 10.5 ± 1.4 g/dl; decrease of 4.1 ± 1.2 g/dl (p ≤ 0.0001). Mean preoperative hematocrit value 43% [41-45], after the procedure; 32% [29-35]; decrease of 11% [8-14] (p ≤ 0.0001). 98 patients had intraoperative bleeding ≥ 300 ml, 129 had ≤ 300 ml; 61.2% of patients with bleeding greater than 300 ml had fibrinogen values below the cut-off point (388 mg/dl). Conclusion: In postoperative patients, preoperative fibrinogen levels ≤ 388 mg/dl and age ≥ 58 years were associated with an increased risk of OR = 0.18 (95% CI 0.10-0.32) of presenting trans-surgical bleeding ≥ 300 ml, with a decrease in Hb of 4.1 ± 1.2 g/dl (p = 0.0001) and Hto of 11% [8-14] (p = 0.0001) between the pre and postoperative period in 48 hours.

Incidence and risk factors for acute kidney injury: a prospective, randomized, single-blind clinical trial comparing total knee arthroplasty with and without tourniquet.

PURPOSE: Identify the incidence and risk factors for acute kidney injury (AKI) following total knee arthroplasty (TKA) with and without tourniquet. MATERIAL AND METHODS: 100 patients were randomized into two groups. Postoperative AKI was defined as the postoperative creatinine level 0.3 mg/dl compared with baseline. Potential variables associated with AKI were analyzed by multivariate logistic regression model to identify the AKI risk factors in TKA patients with and without tourniquet. RESULTS: AKI rate was 22%, tourniquet use (OR = 2.66, p = 0.014), blood loss > 500 cm3 (OR = 3.99, p = 0.001), postoperative Hb < 10 g/dl (OR = 2.68, p = 0.008), blood transfusions (OR = 2.86, p = 0.012) and diabetes (OR = 2.80, p = 0.006) were associated with increased risk of postoperative AKI. CONCLUSIONS: The use of tourniquet should be indicated with caution and should not be used routinely in patients with other risk factors for the development of acute kidney dysfunction, other measures to achieve trans-surgical hemostasis should be implemented in our environment to reduce the incidence of acute kidney dysfunction related to the use of the tourniquet.

PROPÓSITO: Identificar la incidencia y factores de riesgo para lesión renal aguda (LRA) después de la artroplastia total de rodilla (ATR) con y sin uso de torniquete. MATERIAL Y MÉTODOS: Se dividieron 100 pacientes en dos grupos. Se definió la LRA como una elevación postoperatoria de la creatinina 0.3 mg/dl comparada con el nivel basal preoperatorio. Las potenciales variables asociadas con la DRA fueron analizadas con un modelo de regresión logística multivariada para identificar los factores de riesgo de DRA en pacientes sometidos a ATR con y sin torniquete. RESULTADOS: La incidencia de LRA fue de 22%. El uso de torniquete (OR = 2.66, p = 0.014), pérdida sanguínea > 500 cm3 (OR = 3.99, p = 0.001), Hb postoperatoria < 10 g/dl (OR = 2.68, p = 0.008), transfusión sanguínea (OR = 2.86, p = 0.012) y la diabetes (OR = 2.80, p = 0.006) fueron asociados a un mayor riesgo postoperatorio de LRA. CONCLUSIONES: El uso de torniquete debe estar indicado con precaución y no debe utilizarse de forma rutinaria en pacientes con otros factores de riesgo para el desarrollo de disfunción renal aguda, otras medidas para lograr la hemostasia transquirúrgica deben implementarse en nuestro entorno para reducir la incidencia de disfunción renal aguda relacionada con el uso del torniquete.

Incidence and risk factors for acute kidney injury: a prospective, randomized, single-blind clinical trial comparing total knee arthroplasty with and without tourniquet / Incidencia y factores de riesgo para lesión renal aguda: Un ensayo clínico ciego, prospectivo y aleatorizado comparando la artroplastía total de rodilla con y sin torniquete

Abstract: Purpose: Identify the incidence and risk factors for acute kidney injury (AKI) following total knee arthroplasty (TKA) with and without tourniquet. Material and methods: 100 patients were randomized into two groups. Postoperative AKI was defined as the postoperative creatinine level ≥ 0.3 mg/dl compared with baseline. Potential variables associated with AKI were analyzed by multivariate logistic regression model to identify the AKI risk factors in TKA patients with and without tourniquet. Results: AKI rate was 22%, tourniquet use (OR = 2.66, p = 0.014), blood loss > 500 cm3 (OR = 3.99, p = 0.001), postoperative Hb < 10 g/dl (OR = 2.68, p = 0.008), blood transfusions (OR = 2.86, p = 0.012) and diabetes (OR = 2.80, p = 0.006) were associated with increased risk of postoperative AKI. Conclusions: The use of tourniquet should be indicated with caution and should not be used routinely in patients with other risk factors for the development of acute kidney dysfunction, other measures to achieve trans-surgical hemostasis should be implemented in our environment to reduce the incidence of acute kidney dysfunction related to the use of the tourniquet.

Resumen: Propósito: Identificar la incidencia y factores de riesgo para lesión renal aguda (LRA) después de la artroplastia total de rodilla (ATR) con y sin uso de torniquete. Material y métodos: Se dividieron 100 pacientes en dos grupos. Se definió la LRA como una elevación postoperatoria de la creatinina ≥ 0.3 mg/dl comparada con el nivel basal preoperatorio. Las potenciales variables asociadas con la DRA fueron analizadas con un modelo de regresión logística multivariada para identificar los factores de riesgo de DRA en pacientes sometidos a ATR con y sin torniquete. Resultados: La incidencia de LRA fue de 22%. El uso de torniquete (OR = 2.66, p = 0.014), pérdida sanguínea > 500 cm3 (OR = 3.99, p = 0.001), Hb postoperatoria < 10 g/dl (OR = 2.68, p = 0.008), transfusión sanguínea (OR = 2.86, p = 0.012) y la diabetes (OR = 2.80, p = 0.006) fueron asociados a un mayor riesgo postoperatorio de LRA. Conclusiones: El uso de torniquete debe estar indicado con precaución y no debe utilizarse de forma rutinaria en pacientes con otros factores de riesgo para el desarrollo de disfunción renal aguda, otras medidas para lograr la hemostasia transquirúrgica deben implementarse en nuestro entorno para reducir la incidencia de disfunción renal aguda relacionada con el uso del torniquete.

[Preoperative concentration of plasma fibrinogen as a predictor of bleeding in total hip arthroplasty]. / Concentración preoperatoria de fibrinógeno plasmático como predictor de sangrado en artroplastía total de cadera.

INTRODUCTION: Total hip arthroplasty is popular for its success in treating coxarthrosis, its associated with substantial blood loss. Significant bleeding causes complications such as increase in hospitalization days, higher costs, exposing the patient to complications associated with blood transfusion. The aim of the study is to investigate the association between preoperative plasma fibrinogen concentration and trans-surgical bleeding and determine fibrinogen level cut-off to present greater trans-surgical bleeding. MATERIAL AND METHODS: Retrospective, observational, analytical study, from June to December 2020, including 227 patients with Kellgren and Lawrence scale IV coxarthrosis undergoing primary total hip arthroplasty, beneficiaries, older than 18 years, without liver or hematological diseases, and history of significant surgical bleeding. RESULTS: Mean preoperative hemoglobin value was 14.6 ± 1.3 g/dl, after surgery (48 hours) 10.5 ± 1.4 g/dl; decrease of 4.1 ± 1.2 g/dl (p 0.0001). Mean preoperative hematocrit value 43% [41-45], after the procedure; 32% [29-35]; decrease of 11% [8-14] (p 0.0001). 98 patients had intraoperative bleeding 300 ml, 129 had 300 ml; 61.2% of patients with bleeding greater than 300 ml had fibrinogen values below the cut-off point (388 mg/dl). CONCLUSION: In postoperative patients, preoperative fibrinogen levels 388 mg/dl and age 58 years were associated with an increased risk of OR = 0.18 (95% CI 0.10-0.32) of presenting trans-surgical bleeding 300 ml, with a decrease in Hb of 4.1 ± 1.2 g/dl (p = 0.0001) and Hto of 11% [8-14] (p = 0.0001) between the pre and postoperative period in 48 hours.

INTRODUCCIÓN: La artroplastía total de cadera tiene popularidad debido al éxito en el tratamiento de coxartrosis; son procedimientos asociados a la pérdida de sangre. Un sangrado importante provoca complicaciones como aumento en días de estancia intrahospitalaria, mayor costo de la enfermedad, exponiendo al paciente a complicaciones asociadas a transfusión sanguínea. El objetivo del estudio es investigar asociación entre concentración de fibrinógeno plasmático preoperatorio con sagrado transquirúrgico y determinar el nivel de corte de fibrinógeno para presentar mayor sangrado transquirúrgico. MATERIAL Y MÉTODOS: Estudio retrospectivo, observacional, analítico, de Junio a Diciembre de 2020, incluyendo 227 pacientes con coxartrosis IV de la escala de Kellgren y Lawrence sometidos a artroplastía total primaria de cadera, derechohabientes, mayores de 18 años, en ausencia de enfermedades hepáticas o hematológicas y antecedente de sangrado quirúrgico importante. RESULTADOS: El valor promedio de hemoglobina preoperatoria fue 14.6 ± 1.3 g/dl, posterior a cirugía (48 horas) 10.5 ± 1.4 g/dl; observando descenso de 4.1 ± 1.2 g/dl (p 0.0001). Valor promedio del hematocrito prequirúrgico 43% [41-45], posterior al procedimiento 32% [29-35]; se observó descenso de 11% [8-14] (p 0.0001); 98 pacientes presentaron sangrado transquirúrgico 300 ml; 129 tuvieron sangrado 300 ml; 61.2% de pacientes con sangrado mayor de 300 ml mostraron valores de fibrinógeno debajo del punto de corte (388 mg/dl). CONCLUSIÓN: En pacientes postoperados los niveles preoperatorios de fibrinógeno 388 mg/dl y edad 58 años se asociaron al aumento en el riesgo del OR = 0.18 (IC 95% 0.10-0.32) de presentar sangrado transquirúrgico 300 ml, con descenso de la Hb de 4.1 ± 1.2 g/dl (p = 0.0001) y Hto de 11% [8-14] (p = 0.0001) entre el preoperatorio y el postoperatorio en 48 horas.

Psicoestimulantes menores consumidos por estudiantes de la Universidad San Francisco Xavier de Chuquisaca, 2019 / Minor psychostimulants consumed by students of San Francisco Xavier de Chuquisaca University, 2019

El objetivo del estudio fue determinar el consumo de psicoestimulantes en estudiante de la Universidad San Francisco Xavier de Chuquisaca. Se recolectaron los datos mediante encuestas aplicadas a 331 estudiantes. El estudio reveló el psicoestimulante de mayor consumo con 31,88% el café y la coca cola con 26,65%, en su mayoría fueron consumidos con fines académicos. En los efectos secundarios, la sed se estableció como el más frecuente en estudiantes con 30,74%, seguido por cefalea con 27,56% y el cansancio en 14,84%. Se concluye que el café se determina como psicoestimulante menor más consumido en épocas de actividad académica y la sed como el efecto secundario más frecuente.

The objective of the study was to determine the consumption of psychostimulants in a student at the San Francisco Xavier de Chuquisaca University. The data were collected through surveys applied to 331 students. The study revealed the psychostimulant with the highest consumption with 31.88%, coffee and coca cola with 26.65%, most of which were consumed for academic purposes. Regarding side effects, thirst was established as the most frequent in students with 30.74%, followed by headache with 27.56% and fatigue in 14.84%. It is concluded that coffee is determined as the minor psychostimulant most consumed in times of academic activity and thirst as the most frequent side effect.

Novel application of magnetic nano-carbon composite as redox mediator in the reductive biodegradation of iopromide in anaerobic continuous systems.

The redox-mediating capacity of magnetic reduced graphene oxide nanosacks (MNS) to promote the reductive biodegradation of the halogenated pollutant, iopromide (IOP), was tested. Experiments were performed using glucose as electron donor in an upflow anaerobic sludge blanket (UASB) reactor under methanogenic conditions. Higher removal efficiency of IOP in the UASB reactor supplied with MNS as redox mediator was observed as compared with the control reactor lacking MNS. Results showed 82% of IOP removal efficiency under steady state conditions in the UASB reactor enriched with MNS, while the reactor control showed IOP removal efficiency of 51%. The precise microbial transformation pathway of IOP was elucidated by high-performance liquid chromatography coupled to mass spectroscopy (HPLC-MS) analysis. Biotransformation by-products with lower molecular weight than IOP molecule were identified in the reactor supplied with MNS, which were not detected in the reactor control, indicating the contribution of these magnetic nano-carbon composites in the redox conversion of this halogenated pollutant. Reductive reactions of IOP favored by MNS led to complete dehalogenation of the benzene ring and partial rupture of side chains of this pollutant, which is the first step towards its complete biodegradation. Possible reductive mechanisms that took place in the biodegradation of IOP were stated. Finally, the novel and successful application of magnetic graphene composites in a continuous bioreactor to enhance the microbial transformation of IOP was demonstrated.

A rural environment does not protect against asthma or other allergic diseases amongst Mexican children.

INTRODUCTION: The commonly held notion that a rural environment decreases the frequency of allergic diseases has proven to be inconsistent amongst children. OBJECTIVE: Our objective was to contrast the prevalence of bronchial asthma (BA), allergic rhinitis (AR), and atopic dermatitis (AD) between children that live in a rural environment and those that live in urban areas. METHODS: We carried out a cross-sectional study amongst children aged six to seven; they were selected through probabilistic, stratified and conglomerated sampling. The prevalence of BA, AR, and AD was identified with the use of the questionnaire provided by The International Study of Asthma and Allergies in Childhood, additionally, we inquired about each child's family history of atopy, their exposure to farm animals, the intake of unpasteurised cow's milk, and the number of siblings related to every child. We used logistic regression and multivariate analysis to determine the correlation between asthma, allergic diseases, and rural environment. RESULTS: We included 189/1003 (18.8%) children from a rural environment, and 814/1003 (81.2%) from an urban area. BA and AR were associated to a family history of atopy (OR=2.15, p=0.001; OR=2.58, p=0.002, respectively). BA was more prevalent in males (OR=1.92, p=0.007). Notably, a higher number of siblings seems to protect against AR (OR=0.45, p=0.008). A paternal history of allergies was associated to AD. CONCLUSIONS: In our study, we were unable to find protective factors in a rural environment that might decrease the prevalence of asthma or allergic diseases.

Concurrence of Anaerobic Ammonium Oxidation and Organotrophic Denitrification in Presence of p-Cresol.

This study was carried out to evaluate the capacity of anaerobic granular sludge for oxidizing ammonium and p-cresol with nitrate as terminal electron acceptor. Kinetics for the anaerobic oxidation of ammonium and p-cresol is described in this paper. The phenolic compound was very efficiently consumed, achieving 65 % of mineralization. Ammonium and nitrate were also consumed at 83 and 92 %, respectively, being the main product N2. Anaerobic ammonium oxidation was promoted owing to accumulation of nitrite, and it allowed the synergy of anaerobic ammonium oxidation and organotrophic denitrification for the simultaneous removal of ammonium, nitrate, and p-cresol. A carbonaceous intermediate partially identified was transiently accumulated, and it transitorily truncated the respiratory process of denitrification. These experimental results might be considered for defining strategies in order to remove nitrate, ammonium, and phenolic compounds from wastewaters.

Simultaneous oxidation of ammonium and p-cresol linked to nitrite reduction by denitrifying sludge.

The metabolic capability of denitrifying sludge to oxidize ammonium and p-cresol was evaluated in batch cultures. Ammonium oxidation was studied in presence of nitrite and/or p-cresol by 55 h. At 50 mg/L NH4+-N and 76 mg/L NO2--N, the substrates were consumed at 100% and 95%, respectively, being N2 the product. At 50 mg/L NH4+-N and 133 mg/L NO2--N, the consumption efficiencies decreased to 96% and 70%, respectively. The increase in nitrite concentration affected the ammonium oxidation rate. Nonetheless, the N2 production rate did not change. In organotrophic denitrification, the p-cresol oxidation rate was slower than ammonium oxidation. In litho-organotrophic cultures, the p-cresol and ammonium oxidation rates were affected at 133 mg/L NO2--N. Nonetheless, at 76 mg/L NO2--N the denitrifying sludge oxidized ammonium and p-cresol, but at different rate. Finally, this is the first work reporting the simultaneous oxidation of ammonium and p-cresol with the production of N2 from denitrifying sludge.

Immobilized redox mediator on metal-oxides nanoparticles and its catalytic effect in a reductive decolorization process.

Different metal-oxides nanoparticles (MONP) including α-Al(2)O(3), ZnO and Al(OH)(3), were utilized as adsorbents to immobilize anthraquinone-2,6-disulfonate (AQDS). Immobilized AQDS was subsequently tested as a solid-phase redox mediator (RMs) for the reductive decolorization of the azo dye, reactive red 2 (RR2), by anaerobic sludge. The highest adsorption capacity of AQDS was achieved on Al(OH)(3) nanoparticles, which was ∼0.16 mmol g(-1) at pH 4. Immobilized AQDS increased up to 7.5-fold the rate of decolorization of RR2 by anaerobic sludge as compared with sludge incubations lacking AQDS. Sterile controls including immobilized AQDS did not show significant (<3.5%) RR2 decolorization, suggesting that physical-chemical processes (e.g. adsorption or chemical reduction) were not responsible for the enhanced decolorization achieved. Immobilization of AQDS on MONP was very stable under the applied experimental conditions and spectrophotometric screening did not detect any detachment of AQDS during the reductive decolorization of RR2, confirming that immobilized AQDS served as an effective RMs. The present study constitutes the first demonstration that immobilized quinones on MONP can serve as effective RMs in the reductive decolorization of an azo dye. The immobilizing technique developed could be applied in anaerobic wastewater treatment systems to accelerate the redox biotransformation of recalcitrant pollutants.

Induction of tolerance in renal transplantation using splenic transplantation: experimental study in a canine model.

OBJECTIVE: To evaluate in a canine model the induction of tolerance to renal transplantation after splenectomy and splenosis. MATERIALS AND METHODS: This prospective, experimental, comparative, longitudinal study included 4 experimental groups, each comprising 4 dogs. Group 1 (control group) underwent renal transplantation only; group 2 underwent renal transplantation and splenectomy; group 3 underwent renal transplantation and splenosis; and group 4 underwent renal transplantation, splenectomy, and splenosis. Survival and degree of rejection were compared between the 4 groups. RESULTS: Splenosis improved renal function after transplantation, as indicated by increased serum creatinine concentration (group 3, 6.2 mg/dL vs group 1, 12.9 mg/dL). Comparison of weighted survival curves (corrected for degree of rejection) demonstrated a significant difference between group 2 (66.0 days) and group 4 (66.2 days) vs group 1 (52.7 days) and group 3 (41.2 days) (P = .05, Wilcoxon rank sum test). CONCLUSION: These results suggest that in this experimental model of renal transplantation, splenosis and splenectomy induce clinical tolerance, as indicated by improved renal function and prolonged recipient survival.

Effect of nitrate on the reduction of Reactive Red 2 by mesophilic anaerobic sludge.

This research aimed to evaluate the effect of nitrate on anaerobic azo dye reduction by using mesophilic bioreactors, in the absence (reactor R2) and in the presence (reactor R1) of redox mediators. The azo dye Reactive Red 2 (RR2) and the redox mediator anthraquinone-2,6-disulphonate (AQDS) were selected as model compounds. The results showed that the bioreactors were efficient on RR2 reduction, in which ethanol showed to be a good electron donor to sustain dye reduction under anaerobic conditions. The redox mediator AQDS increased the rates of reductive decolourisation, but its effect was not so remarkable compared to the previous experiments conducted. Contrary to the raised hypothesis that the nitrate addition could decrease decolourisation rates and catalytic properties of the redox mediators, no effect of nitrate was observed in the bioreactors, suggesting that the presence of nitrate in textile wastewaters will not decrease the capacity of anaerobic reactors supplemented or not with redox mediators to decolourize azo dyes.

Mortality due to lung cancer in Mexico.

The highest mortality due to cancer worldwide for both genders corresponds to lung cancer (1,179,000 deaths). In Mexico, the crude mortality rate due to lung cancer was of 5.01 per 10(5) inhabitants in 1979. The most important risk factor is smoking. The present study was aimed at analyzing the mortality due to lung cancer in Mexico, assessing data from each of the states constituting the Mexican Republic during the 1998-2004 period. Data were obtained from the National Institute of Statistics, Geography and Informatics (INEGI, for its initials in Spanish) corresponding to deaths due to lung cancer (1998-2004). We estimated the mean annual mortality rate (MAMR) for each of the 32 states of Mexico. We used the "World Population Standard". The MAMR was standardized according to age (ARS) direct method, and the standard error was determined by Poisson's approximation at a 95% confidence interval. To know the excess risk due to mortality, we calculated the standardized mortality ratios (SMRs) of ARS for each federal state, using the national rate as reference. In this period, 397,400 deaths due to malignant neoplasms were recorded, corresponding 45,578 (11.5%) to lung cancer; for men, 31,025 (68.1%) with MAMR of 8.9 and the respective ARS of 13.2 both x10(5) inhabitants. For women, results were 4553 (31.9%) deaths with MAMR of 4.1 and ARS of 5.4 both x10(5) inhabitants. The highest mortality rates due to lung cancer in both genders were observed in the north of Mexico, whereas for women this was observed in the central states. Although smoking is the main risk for lung cancer, there are other factors such as environmental pollution or exposure to toxicants that could be associated to this cancer. The years potentially lost due to lung cancer were 258,550 for men and 133,315 for women, with a total of 391,865 according to histopathology registry neoplasm malignant RHNM (1985-1995). Studies focused on the characterization and measurement of polluting agents would be a good start to determine the level of participation of air pollution in the development of lung cancer.

Catalytic effects of different redox mediators on the reductive decolorization of azo dyes.

The catalytic effects of redox mediators, with distinct standard redox potentials (E'0), were evaluated on the first-order rate constant of decolorization (Kd) of recalcitrant azo dyes by an anaerobic granular sludge. The dyes studied included mono-azo (Reactive Orange 14, RO14), di-azo (Direct Blue 53, DB53), and tri-azo (Direct Blue 71, DB71) compounds. Toxicity and auto-catalytic aspects seemed to play a role in determining the rate of decolorization. Addition of riboflavin, anthraquinone-2,6-disulphonate (AQDS) or lawsone as a redox mediator, increased the Kd value for all dyes studied, although their impact varied in every case. Kd values were increased from 1.1-fold up to 3.8-fold depending on the redox mediator applied. Moreover, catalysts with moderately similar E'0 value caused distinct stimulation on the rate of decolorization. These results should be considered for selecting the proper redox mediator to be applied during the anaerobic treatment of textile wastewaters and effluents containing electron-withdrawing pollutants, such as nitro-aromatic and polychlorinated compounds.

The role of sulphate reduction on the reductive S decolorization of the azo dye reactive orange 14.

The aim of this study was to investigate the impact of a broad range of sulphate concentrations (0-10g SO4(-2) L(-1)) on the reduction of an azo dye (reactive orange 14 (RO14)) by an anaerobic sludge. An increase in the sulphate concentration generally stimulated the reduction of RO14 by sludge incubations supplemented with glucose, acetate or propionate as electron donor. Sulphate and azo dye reductions took place simultaneously in all incubations. However, there was a decrease on the rate of decolorization when sulphate was supplied at 10g SO4(-2) L(-1). Abiotic incubations at different sulphide concentrations (0-2.5 g sulphide L(-1)) promoted very poor reduction of RO14. However, addition of riboflavin (20 microM), as a redox mediator, accelerated the reduction of RO14 up to 44-fold compared to a control lacking the catalyst. Our results indicate that sulphate-reduction may significantly contribute to the reduction of azo dyes both by biological mechanisms and by abiotic reductions implicating sulphide as an electron donor. The contribution of abiotic decolorization by sulphide, however, was only significant when a proper redox mediator was included. Our results also revealed that sulphate-reduction can out-compete with azo reduction at high sulphate concentrations leading to a poor decolorising performance when no sufficient reducing capacity is available.

Nitrogen removal from wastewaters at low C/N ratios with ammonium and acetate as electron donors.

A denitrifying upflow anaerobic sludge blanket (UASB) reactor was operated at different nitrate loading rates at a C/N ratio of 1.2, with acetate as an electron donor. This resulted in an increase in the accumulation of nitrite. After this, the UASB reactor was supplemented with 100 mg NH4+-Nl(-1) d(-1), while acetate was gradually limited in the medium. This prevented nitrite accumulation at a C/N ratio of 0.6 due to an enhanced nitrite reduction rate achieved in the reactor. An increasing amount of ammonium was consumed when the C/N ratio was lowered in the medium. This suggested that ammonium was used as an alternative electron donor during denitrification, which is supported by nitrogen balances. Nitrite was shown to be toxic for the nitrogen removal process at 200-400 mg NO2--N(l(-1) when the C/N ratio was decreased to 0.4 leading to formation of ammonium. The present study showed that addition of ammonium as an alternative electron donor for denitrification achieved a nitrogen removal process with negligible accumulation of undesirable intermediates.

Influence of ammonium on the performance of a denitrifying culture under heterotrophic conditions.

The effect of ammonium on a denitrifying reactor of the upflow anaerobic sludge blanket type was studied. At a constant nitrate loading rate (2500 mg NO3 --N/[L. d]), using acetate as organic electron donor and at a C/NO3 --N/ ratio of 1.23, an increase in the N2 production rate was observed when the ammonium loading rate was increased (25, 250, and 500 mg NH4 +-N/[L. d]). Dissimilatory nitrate reduction to ammonium (DNRA) was not observed, and the N2 production efficiency was increased from 84 to 100% or higher. Since NH4 + in the output was lower than in the input, it was suggested that it was used for nitrate reduction. At constant NH4 +-N/NO3 --N/ and C/NO3 --N/ ratios of 0.2 and 1.63, respectively, the molecular nitrogen production rate was increased at 300 and 500 mg NH4 +-N/(L. d), whereas at 200 mg NH4 +- N/(L. d) DNRA took place probably owing to culture conditions of low reductive power. Molecular nitrogen production was not observed under autotrophic conditions, and the addition of acetate to the culture recovered its high nitrogen removal rate. Experimental results and balances indicated that the consumed ammonium was used as an additional reductive source.

Evaluación del impacto intervenciones centradas en la promoción de la salud y prevención de la violencia en adolescentes del barrio La Paz en el suroccidente de Barranquilla, 2000-2001 / Impact evaluation on central interventions in the health promotion and violence prevention in adolescents from La Paz suburb in the southwest of Barranquilla, 2000-2001

La violencia en Colombia y en sus grandes ciudades ha venido incrementándose desde la década de 1980 por lo que la violencia tanto física como psíquica se ha constituído en este final de siglo, en un factor particular de los niños, los adolescentes y los adultos victimarios; generando una gran pérdida de años de vida saludables y una carga para el sistema de salud al recibir a los afectados. En la presente investigación se trabaja con la violencia relacionada con las personas y en contra de las personas, dado que el homicidio, los accidentes de tránsito y los suicidios, son las más serias manifestaciones de ella; el estudio de la violencia intrafamiliar, será tomado en cuenta como factor de riesgo y como unidad de intervención. Se efectúa una caracterización del problema, en el ámbito de su naturaleza y de su etiología; planteando además las intervenciones que a nivel de promoción de la salud y prevención de la violencia se realizarán en los grupos de adolescentes, para con ello intervenir los factores de riesgo y fomentar los factores protectores y así abordar el problema multifactorial en que se constituye la violencia. La violencia que se ha tomado el país, en todos los ámbitos de la vida cotidiana como una forma de resolver los conflictos, lo que implica igualmente la existencia de conflictos que llevan a actos violentos, también afecta al adolescente