Hyaluronic acid turnover controls the severity of cerebral cavernous malformations in bioengineered human micro-vessels.

Cerebral cavernous malformations (CCMs) are vascular lesions that predominantly form in blood vessels of the central nervous system upon loss of the CCM multimeric protein complex. The endothelial cells within CCM lesions are characterized by overactive MEKK3 kinase and KLF2/4 transcription factor signaling, leading to pathological changes such as increased endothelial cell spreading and reduced junctional integrity. Concomitant to aberrant endothelial cell signaling, non-autonomous signals from the extracellular matrix (ECM) have also been implicated in CCM lesion growth and these factors might explain why CCM lesions mainly develop in the central nervous system. Here, we adapted a three-dimensional microfluidic system to examine CCM1 deficient human micro-vessels in distinctive extracellular matrices. We validate that pathological hallmarks are maintained in this model. We further show that key genes responsible for homeostasis of hyaluronic acid, a major extracellular matrix component of the central nervous system, are dysregulated in CCM. Supplementing the matrix in our model with distinct forms of hyaluronic acid inhibits pathological cell spreading and rescues barrier function. Hyaluronic acid acts by dampening cell-matrix adhesion signaling in CCM, either downstream or in parallel of KLF2/4. This study provides a proof-of-principle that ECM embedded 3D microfluidic models are ideally suited to identify how changes in ECM structure and signaling impact vascular malformations.

The Role of a Loop in the Non-catalytic Domain B on the Hydrolysis/Transglycosylation Specificity of the 4-α-Glucanotransferase from Thermotoga maritima.

The mechanism by which glycoside hydrolases control the reaction specificity through hydrolysis or transglycosylation is a key element embedded in their chemical structures. The determinants of reaction specificity seem to be complex. We looked for structural differences in domain B between the 4-α-glucanotransferase from Thermotoga maritima (TmGTase) and the α-amylase from Thermotoga petrophila (TpAmylase) and found a longer loop in the former that extends towards the active site carrying a W residue at its tip. Based on these differences we constructed the variants W131G and the partial deletion of the loop at residues 120-124/128-131, which showed a 11.6 and 11.4-fold increased hydrolysis/transglycosylation (H/T) ratio relative to WT protein, respectively. These variants had a reduction in the maximum velocity of the transglycosylation reaction, while their affinity for maltose as the acceptor was not substantially affected. Molecular dynamics simulations allow us to rationalize the increase in H/T ratio in terms of the flexibility near the active site and the conformations of the catalytic acid residues and their associated pKas.

Definición de la presión arterial normal a las 11-14 semanas de gestación según riesgo / Definition of normal blood pressure at 11 to 14 weeks' gestation according to risk

Resumen Objetivo: Definir la presión arterial normal en el primer trimestre de la gestación según el desempeño para predecir preeclampsia. Método: Estudio de cohorte en embarazos de feto único, según el modelo de riesgos en competencia para preeclampsia. La presión arterial se midió de manera estandarizada entre las 11 y 14 semanas de gestación. Resultados: En 797 embarazos incluidos hubo 40 (5.0%, intervalo de confianza del 95% [IC 95%]: 3.6-6.4) partos con preeclampsia. Las presiones arteriales sistólica, diastólica y media fueron respectivamente de 101 (9), 68 (8) y 79 (8) mmHg en las embarazadas que no desarrollaron preeclampsia, frente a 109 (10), 75 (8) y 86 (8) mmHg en las que sí (p < 0.001, prueba t de Student). Las áreas bajo la curva fueron 0.707 (0.637-0.777), 0.728 (0.661-0.795) y 0.738 (0.673-0.803). A 3% de falsos positivos, los puntos de corte fueron 119, 83 y 94 mmHg con valores predictivos negativos del 95.6%. Conclusiones: Es factible definir normalidad para la presión arterial en el embarazo con base bioestadística y clínica.

Abstract Objective: To define normal blood pressure at first trimester of pregnancy by performance for pre-eclampsia prediction. Method: A cohort study in singleton pregnancies, according to the competing risks model for pre-eclampsia. Blood pressure was measured according to a standardized method at 11 to 14 weeks' gestation. Results: Among 797 pregnancies included, there were 40 (5.0%, IC95 3.6; 6.4) deliveries with pre-eclampsia. The systolic, diastolic, and mean arterial blood pressures were respectively of 101(9), 68(8) and 79(8) mmHg in pregnant women who did not develop pre-eclampsia, against 109(10), 75(8) and 86(8) in those who did (p < 0.001, t-test). The areas under the curves were 0.707 (0.637; 0.777), 0.728 (0.661; 0.795), and 0.738 (0.673; 0.803). At a 3% of false positive rate, the cut-off points were 119, 83 and 94 mmHg with predictive values of negative of 95.6%. Conclusions: It is feasible to define the normal values for blood pressure in pregnancy on biostatistic and clinical basis.

Definition of normal blood pressure at 11 to 14 weeks' gestation according to risk.

OBJECTIVE: To define normal blood pressure at first trimester of pregnancy by performance for pre-eclampsia prediction. METHOD: A cohort study in singleton pregnancies, according to the competing risks model for pre-eclampsia. Blood pressure was measured according to a standardized method at 11 to 14 weeks' gestation. RESULTS: Among 797 pregnancies included, there were 40 (5.0%, IC95 3.6; 6.4) deliveries with pre-eclampsia. The systolic, diastolic, and mean arterial blood pressures were respectively of 101(9), 68(8) and 79(8) mmHg in pregnant women who did not develop pre-eclampsia, against 109(10), 75(8) and 86(8) in those who did (p < 0.001, t-test). The areas under the curves were 0.707 (0.637; 0.777), 0.728 (0.661; 0.795), and 0.738 (0.673; 0.803). At a 3% of false positive rate, the cut-off points were 119, 83 and 94 mmHg with predictive values of negative of 95.6%. CONCLUSIONS: It is feasible to define the normal values for blood pressure in pregnancy on biostatistic and clinical basis.

OBJETIVO: Definir la presión arterial normal en el primer trimestre de la gestación según el desempeño para predecir preeclampsia. MÉTODO: Estudio de cohorte en embarazos de feto único, según el modelo de riesgos en competencia para preeclampsia. La presión arterial se midió de manera estandarizada entre las 11 y 14 semanas de gestación. RESULTADOS: En 797 embarazos incluidos hubo 40 (5.0%, intervalo de confianza del 95% [IC 95%]: 3.6-6.4) partos con preeclampsia. Las presiones arteriales sistólica, diastólica y media fueron respectivamente de 101 (9), 68 (8) y 79 (8) mmHg en las embarazadas que no desarrollaron preeclampsia, frente a 109 (10), 75 (8) y 86 (8) mmHg en las que sí (p < 0.001, prueba t de Student). Las áreas bajo la curva fueron 0.707 (0.637-0.777), 0.728 (0.661-0.795) y 0.738 (0.673-0.803). A 3% de falsos positivos, los puntos de corte fueron 119, 83 y 94 mmHg con valores predictivos negativos del 95.6%. CONCLUSIONES: Es factible definir normalidad para la presión arterial en el embarazo con base bioestadística y clínica.

Reference values for uterine artery mean pulsatility index throughout pregnancy customized by parity, transvaginal measurement and blood pressure.

INTRODUCTION: Population-specific reference ranges for uterine artery (UtA) mean pulsatility index (PI) throughout pregnancy have been shown to be of value in antenatal care. OBJECTIVE: To construct reference values for UtA mean PI throughout pregnancy, customized by maternal characteristics, transvaginal measurement and blood pressure in a Mexican population. METHODS: Cross-sectional study in 2286 normal singleton pregnancies in Mexico City. Blood pressure and UtA mean PI were measured using standardized methodology. Reference ranges by gestation were constructed. The effects of independent variables were tested by multiple linear regression. RESULTS: UtA mean PI median value between 11 and 41 weeks decreased from 1.714 to 0.523. The 95th percentile decreased from 2.600 to 0.653. Previous parity without preeclampsia had the main effect on UtA mean PI. Mean blood pressure had an effect on UtA mean PI by interaction with parity. Previous preeclampsia had an effect on UtA mean PI by interaction with maternal characteristics. A correction factor was obtained for transvaginal measurement. CONCLUSIONS: UtA mean PI usually decreases according to placentation and maternal adaptation to pregnancy. The effects of parity on blood pressure and UtA mean PI might reflect cardiovascular remodeling after gestation.

INTRODUCCIÓN: Los rangos de referencia de población específica para el índice de pulsatilidad medio de la arteria uterina (IPmAUt) durante el embarazo han demostrado valor en el cuidado prenatal. OBJETIVO: Construir valores de referencia para el IPmAUt durante el embarazo, personalizados por características maternas, medición transvaginal y presión arterial en una población mexicana. MÉTODOS: Estudio transversal de 2286 embarazos normales de feto único en la Ciudad de México. La presión arterial y el IPmAUt se midieron mediante metodología estandarizada. Se construyeron rangos de referencia por gestación. Los efectos de las variables independientes se probaron mediante regresión lineal múltiple. RESULTADOS: La mediana del IPmAUt entre las 11 y 41 semanas disminuyó de 1.714 a 0.523. El percentil 95 disminuyó de 2.600 a 0.653. La paridad sin preeclampsia previa representó el principal efecto sobre el IPmAUt. La presión arterial media tuvo efecto sobre el IPmAUt por interacción con la paridad. La preeclampsia previa tuvo efecto sobre el IPmAUt por interacción con las características maternas. Se obtuvo un factor de corrección para medición transvaginal. CONCLUSIONES: El IPmAUt disminuye normalmente según la placentación y adaptación materna al embarazo. Los efectos de la paridad sobre la presión arterial y el IPmAUt podrían reflejar remodelación cardiovascular posterior a la gestación.

Valores de referencia personalizados para el índice de pulsatilidad medio de la arteria uterina durante el embarazo según paridad, medición transvaginal y presión arterial / Reference values for uterine artery mean pulsatility index throughout pregnancy customized by parity, transvaginal measurement and blood pressure

Resumen Introducción: Los rangos de referencia de población específica para el índice de pulsatilidad medio de la arteria uterina (IPmAUt) durante el embarazo han demostrado valor en el cuidado prenatal. Objetivo: Construir valores de referencia para el IPmAUt durante el embarazo, personalizados por características maternas, medición transvaginal y presión arterial en una población mexicana. Métodos: Estudio transversal de 2286 embarazos normales de feto único en la Ciudad de México. La presión arterial y el IPmAUt se midieron mediante metodología estandarizada. Se construyeron rangos de referencia por gestación. Los efectos de las variables independientes se probaron mediante regresión lineal múltiple. Resultados: La mediana del IPmAUt entre las 11 y 41 semanas disminuyó de 1.714 a 0.523. El percentil 95 disminuyó de 2.600 a 0.653. La paridad sin preeclampsia previa representó el principal efecto sobre el IPmAUt. La presión arterial media tuvo efecto sobre el IPmAUt por interacción con la paridad. La preeclampsia previa tuvo efecto sobre el IPmAUt por interacción con las características maternas. Se obtuvo un factor de corrección para medición transvaginal. Conclusiones: El IPmAUt disminuye normalmente según la placentación y adaptación materna al embarazo. Los efectos de la paridad sobre la presión arterial y el IPmAUt podrían reflejar remodelación cardiovascular posterior a la gestación.

Abstract Introduction: Population-specific reference ranges for uterine artery (UtA) mean pulsatility index (PI) throughout pregnancy have been shown to be of value in antenatal care. Objective: To construct reference values for UtA mean PI throughout pregnancy, customized by maternal characteristics, transvaginal measurement and blood pressure in a Mexican population. Methods: Cross-sectional study in 2286 normal singleton pregnancies in Mexico City. Blood pressure and UtA mean PI were measured using standardized methodology. Reference ranges by gestation were constructed. The effects of independent variables were tested by multiple linear regression. Results: UtA mean PI median value between 11 and 41 weeks decreased from 1.714 to 0.523. The 95th percentile decreased from 2.600 to 0.653. Previous parity without preeclampsia had the main effect on UtA mean PI. Mean blood pressure had an effect on UtA mean PI by interaction with parity. Previous preeclampsia had an effect on UtA mean PI by interaction with maternal characteristics. A correction factor was obtained for transvaginal measurement. Conclusions: UtA mean PI usually decreases according to placentation and maternal adaptation to pregnancy. The effects of parity on blood pressure and UtA mean PI might reflect cardiovascular remodeling after gestation.

Presión arterial en embarazos normales de la Ciudad de México / Blood pressure in normal pregnancies from Mexico City

Resumen Objetivo: Determinar la presión arterial (PA) normal en embarazadas en la Ciudad de México. Método: Estudio transversal descriptivo de la PA en embarazos normales de feto único en la Ciudad de México. Las mediciones siguieron un método estandarizado con uso de dispositivos electrónicos automatizados. Se construyeron valores de referencia de las presiones sistólica (PS), diastólica (PD) y arterial media (PAM). Se probaron los efectos de las características maternas y de la gestación sobre la PA. Los intervalos de referencia de la PA se ajustaron para las variables significativas. Resultados: En 1,056 mujeres con edad media de 33 años y 160 cm medios de estatura se realizaron 1,915 mediciones entre las 5 y 41 semanas de edad gestacional (EG) con peso medio de 65 kg. La PA durante el embarazo fue de 102.7/67.2 ± 9.3/7.4 DE mmHg y 79.0 ± 7.4 DE mmHg la PAM. La PA tuvo una relación cuadrática con la EG, la más baja en el segundo trimestre. La PS y la PD mostraron una correlación lineal (r = 0.71). El peso materno tuvo el efecto más significativo sobre PS y PAM; la estatura sobre la PD. La edad, etnia, paridad, consumo de tabaco y antecedente familiar ejercieron efectos diferentes en cada PA. La gestación no tuvo efecto significativo en el modelo multivariado de la PS. Conclusiones: La PA se halló por debajo de la norma convencional en embarazadas. Los criterios diagnósticos para hipertensión en el embarazo deben revisarse; los valores de referencia pueden ajustarse a características maternas y gestacionales.

Abstract Objective: To determine the normal blood pressure (BP) in pregnancy, Mexico City. Methods: A cross-sectional observational study was carried out of BP on singleton normal pregnancies in Mexico City. Measurements followed a standardised methodology using automated electronic devices. Reference values of systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP) were constructed. Maternal and gestation characteristics effects on BP were tested. The reference ranges of BP were adjusted for significant variables. Results: On 1,056 women of 33 years old mean age and 160.0 cm mean height, 1,915 measurements were made between 5 and 41 weeks of gestational age (GA) with 65.0 kg of mean weight. The median BP throughout pregnancy was 102.7/67.2 ± 9.3/7.4 SD mmHg, and 79.0 ± 7.4 SD mmHg the MAP. BP had a quadratic relationship with GA, being the lowest in 2nd trimester. SBP and DBP had a r = 0.71 linear correlation. Maternal weight had the most significant effect on SBP and MAP; height, on DBP. Maternal age, ethnic origin, parity, tobacco habit and family history had differential effects on BP. Gestation had no significant effect on SBP multivariate model. Conclusions: BP resulted lower than conventional standard for pregnant women. Diagnostic criteria for hypertension in pregnancy must be revised; reference values can be adjusted by maternal and gestation characteristics.

Presión arterial en embarazos normales de la Ciudad de México.

OBJECTIVE: To determine the normal blood pressure (BP) in pregnancy, Mexico City. METHODS: A cross-sectional observational study was carried out of BP on singleton normal pregnancies in Mexico City. Measurements followed a standardised methodology using automated electronic devices. Reference values of systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP) were constructed. Maternal and gestation characteristics effects on BP were tested. The reference ranges of BP were adjusted for significant variables. RESULTS: On 1,056 women of 33 years old mean age and 160.0 cm mean height, 1,915 measurements were made between 5 and 41 weeks of gestational age (GA) with 65.0 kg of mean weight. The median BP throughout pregnancy was 102.7/67.2 ± 9.3/7.4 SD mmHg, and 79.0 ± 7.4 SD mmHg the MAP. BP had a quadratic relationship with GA, being the lowest in 2nd trimester. SBP and DBP had a r = 0.71 linear correlation. Maternal weight had the most significant effect on SBP and MAP; height, on DBP. Maternal age, ethnic origin, parity, tobacco habit and family history had differential effects on BP. Gestation had no significant effect on SBP multivariate model. CONCLUSIONS: BP resulted lower than conventional standard for pregnant women. Diagnostic criteria for hypertension in pregnancy must be revised; reference values can be adjusted by maternal and gestation characteristics.

OBJETIVO: Determinar la presión arterial (PA) normal en embarazadas en la Ciudad de México. MÉTODO: Estudio transversal descriptivo de la PA en embarazos normales de feto único en la Ciudad de México. Las mediciones siguieron un método estandarizado con uso de dispositivos electrónicos automatizados. Se construyeron valores de referencia de las presiones sistólica (PS), diastólica (PD) y arterial media (PAM). Se probaron los efectos de las características maternas y de la gestación sobre la PA. Los intervalos de referencia de la PA se ajustaron para las variables significativas. RESULTADOS: En 1,056 mujeres con edad media de 33 años y 160 cm medios de estatura se realizaron 1,915 mediciones entre las 5 y 41 semanas de edad gestacional (EG) con peso medio de 65 kg. La PA durante el embarazo fue de 102.7/67.2 ± 9.3/7.4 DE mmHg y 79.0 ± 7.4 DE mmHg la PAM. La PA tuvo una relación cuadrática con la EG, la más baja en el segundo trimestre. La PS y la PD mostraron una correlación lineal (r = 0.71). El peso materno tuvo el efecto más significativo sobre PS y PAM; la estatura sobre la PD. La edad, etnia, paridad, consumo de tabaco y antecedente familiar ejercieron efectos diferentes en cada PA. La gestación no tuvo efecto significativo en el modelo multivariado de la PS. CONCLUSIONES: La PA se halló por debajo de la norma convencional en embarazadas. Los criterios diagnósticos para hipertensión en el embarazo deben revisarse; los valores de referencia pueden ajustarse a características maternas y gestacionales.

A Drastic Shift in Lipid Adducts in Colon Cancer Detected by MALDI-IMS Exposes Alterations in Specific K+ Channels.

Even though colorectal cancer (CRC) is one of the most preventable cancers, it is one of the deadliest, and recent data show that the incidence in people <50 years has unexpectedly increased. While new techniques for CRC molecular classification are emerging, no molecular feature is as yet firmly associated with prognosis. Imaging mass spectrometry (IMS) lipidomic analyses have demonstrated the specificity of the lipid fingerprint in differentiating pathological from healthy tissues. During IMS lipidomic analysis, the formation of ionic adducts is common. Of particular interest is the [Na+]/[K+] adduct ratio, which already functions as a biomarker for homeostatic alterations. Herein, we show a drastic shift of the [Na+]/[K+] adduct ratio in adenomatous colon mucosa compared to healthy mucosa, suggesting a robust increase in K+ levels. Interrogating public databases, a strong association was found between poor diagnosis and voltage-gated potassium channel subunit beta-2 (KCNAB2) overexpression. We found this overexpression in three CRC molecular subtypes defined by the CRC Subtyping Consortium, making KCNAB2 an interesting pharmacological target. Consistently, its pharmacological inhibition resulted in a dramatic halt in commercial CRC cell proliferation. Identification of potential pharmacologic targets using lipid adduct information emphasizes the great potential of IMS lipidomic techniques in the clinical field.

Validation of a preeclampsia early screening test in a Mexican population.

BACKGROUND: No preeclampsia screening test has been validated in our country. OBJECTIVE: To assess the fit and performance of the FMF 4.0 Bayesian algorithm in a Mexican population. METHOD: Cohort study in singleton pregnancies, according to the competing risks model for preeclampsia. A priori risk was calculated based on medical history. Mean blood pressure (MBP), uterine artery mean pulsatility index (UtAmPI) and pregnancy-associated plasma protein A (PAPP-A) were measured at 11-14 weeks of gestation using standardized methodology. The value of each marker was transformed into multiples of the median (MoM) by the originala algorithm and by population-correctionb. Multivariate normal distribution and Bayes theorem were applied to obtain post-test probabilities. RESULTS: There was 5.0% (40/807) of preeclampsia. Distributions in women without preeclampsia were MBP = 0.927a vs. 0.991b, UtAmPI = 0.895a vs. 1.030b and PAPP-A = 0.815a vs. 0.963b (p < 0.001). The AUC was 0.821a vs. 0.823b. For a detection rate of 69 %, cutoff points were 1 in 240a and 1 in 120b, with false positive rates of 31 %a and 29 %b. CONCLUSIONS: The model has to be adjusted to the target population.

ANTECEDENTES: Ninguna prueba de tamiz de preeclampsia ha sido validada en nuestro país. OBJETIVO: Evaluar el ajuste y rendimiento del algoritmo bayesiano FMF 4.0 en una población mexicana. MÉTODO: Estudio de cohorte en embarazos de feto único, según el modelo de riesgos en competencia para preeclampsia. El riesgo a priori se calculó por historia clínica. La presión arterial media (PAM), el índice de pulsatilidad medio de la arteria uterina (IPmAUt) y la proteína plasmática A asociada al embarazo (PAPP-A) se midieron a las 11-14 semanas de gestación con metodología estandarizada. El valor de cada marcador se transformó en múltiplos de la mediana (MoM) por el algoritmo originala y el corregidob a la población. Se aplicaron la distribución normal multivariante y el teorema de Bayes para las probabilidades posprueba. RESULTADOS: Hubo un 5.0% (40/807) de preeclampsia. Las distribuciones sin preeclampsia fueron PAM 0.927a vs. 0.991b, UtAmPI 0.895a vs. 1.030b y PAPP-A 0.815a vs. 0.963b (p < 0.001). El área bajo la curva fue 0.821a vs. 0.823b. Para una detección del 69%, los puntos de corte fueron 1 en 240a y 1 en 120b, a falsos positivos del 31%a y 29%b. CONCLUSIONES: El modelo debe ajustarse a la población diana.

Review of Medical Management of Primary Biliary Cholangitis.

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease with presumed autoimmune etiology. Current treatment options include ursodeoxycholic acid, obeticholic acid, and fibrate, which target mainly cholestasis. There is no effective therapy against autoimmune or hepatic fibrosis components. We can still achieve adequate biochemical response with monotherapy or a combination of medications in non-cirrhotic and compensated cirrhotic PBC patients. Several criteria are available for risk stratification and assess treatment response. Liver stiffness measurement by transient elastography is also a useful tool for evaluating disease progression. Lack of treatment or inadequate response are predictors of poor outcome. There is a strong need for additional therapies for PBC.

Castleman's Disease and Posttransplant Lymphoproliferative Disorder after Liver Transplant: 3-Year Follow-Up.

A 59-year-old male with a history of hepatitis C cirrhosis and history of hepatitis B exposure presented 8 months after orthotopic liver transplant (LT) with fever, fatigue, myalgia, night sweats, nonproductive cough, and shortness of breath. Bone marrow biopsy for pancytopenia was positive for Epstein-Barr virus (EBV) DNA. Lymph node biopsy for lymphadenopathy on imaging showed human herpes virus 8 (HHV8) associated Castleman's disease. Treatment included valganciclovir, rituximab, and prednisone taper with eventual discontinuation. Quantitative HHV8 DNA was initially 611,000 DNA copies/mL and was later undetectable at 6 months following treatment and remained undetectable at 3-year follow-up.

Impact of anti-thymocyte globulin during immunosuppression induction in patients with hepatitis C after liver transplantation.

BACKGROUND: Induction immunosuppression with anti-thymocyte globulin (ATG) provides potential benefits after liver transplantation (LT). However, its use in patients with LT and hepatitis C (HCV) is controversial. AIM: To evaluate the 1- and 2-year patient survival and HCV recurrence rate in patients receiving ATG during the induction phase of immunosuppression (IPI) after LT. METHODS: A total of 49 patients undergoing their first LT for HCV were randomized to receive ATG during IPI. Patient survival and HCV recurrence were determined at 1 and 2 years. The frequency of acute cellular rejection (ACR), infections, and neoplasms was also evaluated. RESULTS: Twenty-six patients were randomized to receive ATG (Arm-1) and 23 to standard induction therapy (Arm-2). Those given ATG had lower HCV recurrence (26.9 vs 73.9 %, p = 0.001). The 1- and 2-year patient survival rates were similar for both arms (p = 0.33). Infections occurred in 46.1 % subjects in Arm-1 and 34.7 % in Arm-2 (p = 0.562). There was a greater proportion of fungal infections in Arm-1 (19.2 vs 0 %, p = 0.032). CONCLUSIONS: ATG during the IPI was associated with lower frequency of recurrence of HCV in patients undergoing LT. This, however, did not affect the 1- and 2-year survival and the frequency of ACR, infections, or neoplasms.

Chemical characterization and factor analysis of PM2.5 in two sites of Monterrey, Mexico.

The Monterrey Metropolitan Area (MMA) has shown a high concentration of PM2.5 in its atmosphere since 2003. The contribution of possible sources of primary PM2.5 and its precursors is not known. In this paper we present the results of analyzing the chemical composition of sixty 24-hr samples of PM2.5 to determine possible sources of PM2.5 in the MMA. The samples were collected at the northeast and southeast of the MMA between November 22 and December 12, 2007, using low-volume devices. Teflon and quartz filters were used to collect the samples. The concentrations of 16 airborne trace elements were determined using x-ray fluorescence (XRF). Anions and cations were determined using ion chromatography. Organic carbon (OC) and elemental carbon (EC) were determined by thermal optical analysis. The results show that Ca had the maximum mean concentration of all elements studied, followed by S. Enrichment factors above 50 were calculated for S, Cl, Cu, Zn, Br and Pb. This indicates that these elements may come from anthropogenic sources. Overall, the major average components of PM2.5 were OC (41.7%), SO4(2-) (22.9%), EC (7.4%), crustal material (11.4%), and NO3- (12.6%), which altogether accounted for 96% of the mass. Statistically, we did not find any difference in SO4(2-) concentrations between the two sites. The fraction of secondary organic carbon was between 24% and 34%. The results of the factor analysis performed over 10 metals and OC and EC show that there are three main sources of PM2.5: crustal material and vehicle exhaust; industrial activity; and fuel oil burning. The results show that SO4(2-), OC, and crustal material are important components of PM2.5 in MMA. Further work is necessary to evaluate the proportion of secondary inorganic and organic aerosol in order to have a better understanding of the sources and precursors of aerosols in the MMA.

Prevalence of antibodies to Theileria equi and Babesia caballi in horses from northeastern Mexico.

The objective of this study was to obtain an estimate for seroprevalences of Theileria equi (Babesia equi) and Babesia caballi in horses from northeastern Mexico. Sera were collected in spring of 2007 in 248 clinically healthy horses used for different purposes. Antibodies were detected by the indirect immunofluorecent technique. The overall seroprevalence was 61.7% and those for T. equi and B. caballi were 45.2% and 27.4%, respectively. Horse purpose, sex, and age group were not associated with infection with Theileria equi or Babesia caballi.