Biochemical characteristics and modulation by external and internal factors of aminopeptidase-N activity in the hepatopancreas of a euryhaline burrowing crab.

Strikingly, in spite of its physiological importance, information about occurrence, biochemical characteristics and mechanisms of regulation of aminopeptidase-N (APN) in the hepatopancreas of intertidal euryhaline crabs is still lacking. In this work, we determined the occurrence, biochemical characteristics, response to environmental salinity and dopamine of APN in the hepatopancreas of the euryhaline crab Neohelice granulata (Dana 1851) from the open mudflat of Mar Chiquita coastal lagoon (Buenos Aires province, Argentina). APN activity was maximal at pH and temperature range of 7.6-9.0 and 37-45 °C, respectively. APN activity exhibited Michaelis-Menten kinetics (apparent Km = 0.19 ± 0.10 mM) (pH 7.6, 37 °C) and appeared to be sensitive to bestatin (I 50 = 15 mM) and EDTA (I 50 = 9 mM). In crabs acclimated to 10 psu (hyper-regulation conditions) and 37 psu (hypo-regulation conditions), APN activity was about 45 and 160% higher, respectively, than in 35 psu (osmoconformation). APN activity in the hepatopancreas was stimulated in vitro (about 137%) by 10(-4) M dopamine. Higher dopamine concentrations produced a similar extent of increase. The responses of APN activity to salinity and dopamine in vitro suggest the role of APN in digestive adjustments upon hyper and hypo-regulatory conditions and its modulation via direct mechanisms on hepatopancreas by dopamine.

What do we know about Q fever in Mexico?

In Mexico, Q fever is considered a rare disease among humans and animals. From March to May of 2008, three patients were referred, from the state of Hidalgo to a tertiary-care center in Mexico City, with an acute febrile illness that was diagnosed as Q fever. We decided to undertake a cross sectional pilot study to identify cases of acute disease in this particular region and to determine the seroprevalence of Coxiella burnetii among healthy individuals with known risk factors for infection with this bacteria. Q fever was defined according to the Centers for Disease Control and Prevention criteria. All subjects were interviewed for signs and symptoms of the disease, demographic and household characteristics and occupational exposure to cattle. Blood samples were taken from hospitalized and outpatients with symptoms suggestive of Q fever, as well as from asymptomatic individuals with direct and daily exposure to cattle (slaughterers, butchers, farmers, shepherds and veterinarians) in the five municipalities. We report the occurrence of 17 cases with positive antibodies against C. burnetii in a rural area of central Mexico; eight cases had clinical criteria of acute Q fever disease. Results from this pilot study underscore the need for active surveillance programs and comprehensive studies to further define the prevalence and risk factors associated with the disease in Mexico, to know more about its clinical presentation and to characterize bacterial factors involved in its pathogenesis.

[Active tuberculosis in a cohort of HIV-infected inmates in a prison in Mexico City: clinical and epidemiological characteristics]. / Tuberculosis activa en una cohorte de reclusos infectados por VIH en una cárcel de la Ciudad de México: características clínicas y epidemiológicas.

OBJECTIVE: To determine the clinical and epidemiological characteristics of prison inmates with active tuberculosis in HIV-positive prison populations. MATERIALS AND METHODS: We conducted a cohort study in HIV-infected subjects in a prison in Mexico City, with the aim of determining clinical and epidemiological characteristics of cases with active TB. RESULTS: We detected 172 HIV infected inmates and TB in 28 of them (16.3%) - 21 (12.2) with pulmonary TB--with an incidence rate of 7.7/100 persons/year for active TB and 4.7/100 persons/year for pulmonary TB. No drug resistance was found. Two clusters (4 and 2 subjects) were observed after RFLP-typing of 18 isolates, with a transmission rate of 11% by molecular and clinical analysis. CONCLUSIONS: The prevalence of active TB was found to be a thousand times greater than in the general population. Evidence of transmission inside the prison was also found.

Corrosion inhibition of powder metallurgy Mg by fluoride treatments.

Pure Mg has been proposed as a potential degradable biomaterial to avoid both the disadvantages of non-degradable internal fixation implants and the use of alloying elements that may be toxic. However, it shows excessively high corrosion rate and insufficient yield strength. The effects of reinforcing Mg by a powder metallurgy (PM) route and the application of biocompatible corrosion inhibitors (immersion in 0.1 and 1M KF solution treatments, 0.1M FST and 1M FST, respectively) were analyzed in order to improve Mg mechanical and corrosion resistance, respectively. Open circuit potential measurements, polarization techniques (PT), scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS) were performed to evaluate its corrosion behavior. SECM showed that the local current of attacked areas decreased during the F(-) treatments. The corrosion inhibitory action of 0.1M FST and 1M FST in phosphate buffered solution was assessed by PT and EIS. Under the experimental conditions assayed, 0.1M FST revealed better performance. X-ray photoelectron spectroscopy, energy dispersive X-ray and X-ray diffraction analyses of Mg(PM) with 0.1M FST showed the presence of KMgF(3) crystals on the surface while a MgF(2) film was detected for 1M FST. After fluoride inhibition treatments, promising results were observed for Mg(PM) as degradable metallic biomaterial due to its higher yield strength and lower initial corrosion rate than untreated Mg, as well as a progressive loss of the protective characteristics of the F(-)-containing film which ensures the gradual degradation process.

Molecular epidemiology and risk factors of bloodstream infections caused by extended-spectrum beta-lactamase-producing Klebsiella pneumoniae A case-control study.

OBJECTIVES: To study the prevalence, risk factors, outcome, and molecular epidemiology in patients with bacteremia caused by extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae (Kp) (cases), in comparison with patients with bacteremia caused by a susceptible Kp (controls). METHODS: This was a retrospective case-control study including all episodes of Kp bacteremia for the period 1993 to 2002 at a referral hospital for adults in Mexico. ESBL production was tested for by E-test. All isolates were typed by pulsed field gel electrophoresis (PFGE). A subset of isolates underwent plasmid analysis, conjugal transfer of cefotaxime resistance to Escherichia coli J53-2, isoelectric focusing bioassay, colony-blot hybridization, PCR, and sequencing. RESULTS: Of the 121 patients with bacteremia due to Kp included in the study, 17 (14.0%) had an ESBL-Kp isolate (cases). Multivariate analysis identified prior use of cephalosporins (OR 7.6, 95% CI 1.1-53.5; p=0.039) and stay in the intensive care unit (ICU; OR 5.6, 95% CI 1.1-27.9; p=0.033) as significant risk factors. No differences were observed in hospital stay or mortality after the event. Multi-drug resistance was more frequent in ESBL-Kp. There was no clonal predominance. A distinct beta-lactamase profile was identified, which included a combination of TEM-1 (pI 5.4) and SHV-5 (pI 8.2) in 13/17 ESBL-Kp isolates. Cefotaxime resistance was transferred by conjugation in 14/17 isolates with a >120-kb plasmid encoding ESBL. CONCLUSIONS: The prevalence of ESBL-Kp was found to be lower than that previously reported in Latin America. ESBL-Kp bacteremia was not associated with a worse clinical outcome. We were able to identify a plasmid-mediated horizontal dissemination over the 10-year period.

Solid mining residues from ni extraction applied as nutrients supplier to anaerobic process: optimal dose approach through Taguchi's methodology.

The use of solid mining residues (Cola) which contain a certain amount of Ni, Fe and Co, to stimulate anaerobic processes was evaluated. The effect over methane production and chemical oxygen demand (COD) removal efficiency was analysed. The studies were carried out in discontinuous reactors at lab scale under mesophilic conditions until exhausted. 0, 3, 5 and 7 mg Cola l(-1) doses were applied to synthetic wastewater. Volatile fatty acids (VFA) and sucrose were used as substrate, sulphur and nitrogen concentration, being the noise variable. Cola addition at dose around 5 mg I(-1), turned out to be stimulating for the anaerobic process. It was the factor that most influenced on methane production rate together with VFA and high content of volatile suspended solids. In the case of methane yield, pH was the control factor of strongest influence. Higher values of COD removal efficiency were obtained when the reactors were operated with sucrose at relatively low pH and at the smallest concentration of nitrogen and sulphur. Solid residues dose and the type of substrate were the factors that had most influence on COD removal efficiency.

Consumption costs of inappropriate medicines estimated from bulk purchase data: The example of NSAids in Guatemala.

OBJECTIVE: In contexts where access to medicines is limited or troublesome, it may be important to identify the cases in which there exists access to medicines, but where this access is "inefficient" because it results in non-healing, avoidable toxicity or excessive cost in conditions of similar efficacy. Despite obvious limitations, bulk medicines purchase data of public institutions used to be the only available approximation on what is consumed in some countries. The aim of this study was to describe the results of a qualitative analysis of bulk consumption data, focusing on nonsteroidal anti-inflammatory drugs (NSAIDs) as an example. METHOD: The list of all drugs purchased by the Health Ministry of Guatemala in 2004 was quantitatively and qualitatively analyzed both according to the number of units and value. All NSAIDs bought during that period were analyzed in order to find potential intervention areas which could be addressed to improve drug selection. RESULTS: The studied list included 693 products with a value of 102 million US dollars. Among the top-20 purchased medicines by defined daily doses (DDDs) were several NSAIDs (including aceclofenac, meloxicam and piroxicam). Ranitidine, ciprofibrate and dimethicone were also among these top-20 drugs. In addition, aceclofenac was among the top-20 drugs according to value. The cost of "second-line" NSAIDs was several times higher than the "first-line" diclofenac or ibuprofen. Providing equal efficacy and similar toxicity exists, a theoretical switch from second- to first-line NSAIDs could save up to 2,377 million US dollars/year. CONCLUSIONS: Although it is an old and well-known method, the analysis of bulk consumption data continues to provide information that may help to identify areas of potential improvement in settings without many resources. In the present theoretical example, educative interventions addressed to rational selection of NSAIDs could save more than 2% of the annual drug expenditure of the country. Co-ordinated actions addressed to other drugs could decrease inefficient drug expenditure and improve the quality of health-care.

Pieloplastía no desmembrada tipo by pass / By pass type non-demembrated pyeloplasty

Presentamos una técnica no desmembrada de plastía pielo ureteral, que utilizamos en casos complejos de estenosis pielo ureteral (EPU) con severo daño funcional, infección y fibrosis local. Se trata de efectuar un puente entre pelvis y uréter sin mayor disección. Presentamos 14 casos intervenidos con más de un año de observación y evaluación, 9 de ellos pacientes adultos y 6 pediátricos. De ellos 12 recuperan función renal deteriorada y 8 mejoran el aspecto morfológico. Uno no se modifica y otro debe efectuarse una nefrectomía por sepsis

Resistencia de Mycobacterium tuberculosis en pacientes mexicanos. I. Características clínicas y factores de riesgo / Drug resistence of M. tuberculosis in Mexican patients: I. clinical manifestations and risk factors

Objetivo. Determinar las manifestaciones asociadas con la infección por M. tuberculosis resistente y la susceptibilidad antimicrobiana de aislados de pacientes mexicanos. Diseño. Vigilancia epidemiológica. Sitio. Centro de tercer nivel. Pacientes. Casos de tuberculosis confirmada. Mediciones. Resistencia primaria: cuando no hubo antecedente de tratamiento, y secundaria cuando lo hubo. Se emplearon las siguientes concentraciones críticas (µg/mL): son isoniacida 0.2 y 1; rifampicina 1 y 5; etambutol 5 y 10; estreptomicina 2 y 10; etionamida 5; kanamicina 6; y ácido paraaminosalicílio (PAS) 2 y 10. Resultados. Se incluyeron 84 pacientes con edad promedio de 44.7 años (6-80 años); 54 hombres (64 por ciento) y 30 mujeres (36 por ciento). La mayoría (35/62) del Distrito Federal y del Estado de México. Sólo en 34 pacientes se obtuvo información clínica: 26 presentaron fiebre y pérdida de peso, y ocho síntomas respiratorios. Se encontraron 59 pacientes (70 por ciento) con M. tuberculosis sensible y 25 resistente (30 por ciento). En 17 (68 por ciento) hubo resistencia a dos drogas y 16 (64 por ciento) de ellos a isoniacida y rifampicina. La tasa de resistencia global fue: isoniacida 24 por ciento, rifampicina 19 por ciento, estreptomicina 12 por ciento, etambutol 10 por ciento, PAS 9 por ciento, etianamida 7 por ciento y kanamicina 6 por ciento. En 47 pacientes sin tratamiento previo, ocho tuvieron infección por organismos resistentes (17 por ciento), y la tasa de resistencia primaria fue: isoniacida 9 por ciento, rifampicina 6 por ciento, estreptomicina 2 por ciento, etambutol 2 por ciento, PAS 6 por ciento y multirresistencia 6 por ciento. De 37 pacientes con tratamiento previo, 17 (46 por ciento) tuvieron un organismo resistente, y la tasa de resistencia secundaria fue: isoniacida 44 por ciento, rifampicina 35 por ciento, estreptomicina 24 por ciento, etambutol 19 por ciento, PAS 12 por ciento y multirresistencia 35 por ciento. Incluimos cuatro médicos con M. tuberculosis mono o multirresistente y siete pacientes con SIDA, uno de ellos con multirresistencia y otro con resistenia a isoniacida. Conclusión. Los resultados muestran tasas elevadas de resistencia a isoniacida y rifampicina, y de multirresistencia en M. tuberculosis aislado de pacientes mexicanos

[Resistance of Mycobacterium tuberculosis in Mexican patients. I. Clinical features and risk factors]. / Resistencia de Mycobacterium tuberculosis en pacientes mexicanos. I. Características clínicas y factores de riesgo.

OBJECTIVE: To determine the clinical manifestations associated with resistant M. tuberculosis infection and the antimicrobial resistance in isolates from Mexican patients. STUDY DESIGN: Epidemiological surveillance. PATIENTS: Tuberculosis confirmed cases. METHODS: Primary resistance: no history of treatment prior to diagnosis. The following critical concentrations (micrograms/mL) were used for susceptibility: isoniazid 0.2 and 1; rifampin 1 and 5; ethambutol 5 and 10; streptomycin 2 and 10; ethionamide 5; kanamycin 6; and para-aminosalicylic acid (PAS) 2 and 10. RESULTS: Eighty-four patients with a mean age of 44.7 years were included; 54 men (64%) and 30 women (36%); most patients were from the Mexico City metropolitan area. In 34 patients there was clinical information available, 26 presented fever and weight loss and 8 respiratory symptoms. Fifty-nine patients (70%) were infected by pan-susceptible M. tuberculosis, and 25 (30%) by a resistant isolate; 17 (68%) of them were resistant to at least two drugs, 16 (64%) to isoniazid and rifampin. The proportion of resistance was: isoniazid 24%, rifampin 19%, streptomycin 12%, ethambutol 10%, PAS 9%, etionamide 7%, and kanamycin 6%. Of 47 patients without previous treatment, eight had a resistant microorganism (17%): 9% resistant to isoniazid, 6% to rifampin, 2% to streptomycin, 6% to PAS and 6% multiresistant. Of 37 patients with history of previous treatment for tuberculosis, 17 (46%) had a resistant isolate; 44% were resistant to isoniazid, 35% to rifampin, 24% to streptomycin, 19% to ethambutol, 12% to PAS and 35% multiresistant. Of the 84 patients, four were physicians infected by a resistant isolate, and seven HIV-infected patients, one with a multiresistant isolate, and another with isoniazid resistance. CONCLUSIONS: Antimicrobial resistance among M. tuberculosis is alarmingly high in Mexico City; these results emphasize the importance of case detection and early isolation of patients.

Human monoclonal antibodies against an epitope on the class 5c outer membrane protein common to many pathogenic strains of Neisseria meningitidis.

Neisseria meningitidis is a causative agent of meningitis. Despite vaccination programs, it still causes a large number of deaths in young children. Early diagnosis followed by passive immunization with human monoclonal antibodies could be an approach to effective therapy. Peripheral blood lymphocytes from normal, healthy blood donors and from vaccinated individuals were immunized in vitro, using outer membrane proteins purified from N. meningitidis B:4:P1.15. The immunized human B cells were Epstein-Barr virus transformed and fused to a heteromyeloma. Several stable human hybridoma cell lines were established and two, secreting antibodies against the 31-kDa class 5c outer membrane protein, were characterized further. The human antibodies were of IgG1 and IgG3 isotypes, with kappa light chains. The recognized epitope was commonly found among pathogenic strains of N. meningitidis; thus, these human monoclonal antibodies may be important in the evaluation of N. meningitidis infections.

Timing of permanent tooth emergence in a Southeastern Dominican schoolchildren population sample.

The purpose of this study was to establish the mean timing of permanent tooth emergence in a low to middle socioeconomic level schoolchildren population sample from the Southeastern part of the Dominican Republic. A total of 900 children (15.6% of the 5-14-year-old schoolchildren from this city) were studied. Girls were relatively advanced in their emergence times except for the canine and second premolar in the maxilla and the first premolar in the mandible. The mean emergence times were, in general, relatively advanced when compared with those of United States whites and blacks, Danish, Canadian Eskimos, French-Canadians, Greenland Eskimos, Icelandics, Southern Chinese and South Africans.