ABCG2 polymorphism and rivaroxaban pharmacokinetics in healthy individuals after a single dose

Rivaroxaban is a direct factor Xa inhibitor. Its interindividual variability is large and may be connected to the occurrence of adverse drug reactions or drug inefficacy. Pharmacogenetics studies concentrating on the reasons underlying rivaroxaban's inadequate response could help explain the differences in treatment results and medication safety profiles. Against this background, this study evaluated whether polymorphisms in the gene encoding the ABCG2 transporter modify the pharmacokinetic characteristics of rivaroxaban. A total of 117 healthy volunteers participated in two bioequivalence experiments with a single oral dose of 20 mg rivaroxaban, with one group fasting and the other being fed. Ultra-high-performance liquid chromatography coupled with mass spectrometry was employed to determine the plasma concentrations of rivaroxaban, and the WinNonlin program was used to calculate the pharmacokinetics parameters. In the fasting group, the rivaroxaban pharmacokinetic parameters of Vd (508.27 vs 334.45 vs 275.59 L) and t1/2 (41.04 vs 16.43 vs 15.47 h) were significantly higher in ABCG2 421 A/A genotype carriers than in ABCG2 421 C/C and 421 C/A genotype carriers (P<0.05). The mean values of Cmax (145.81 vs 176.27 vs 190.19 ng/mL), AUC0-t (1193.81 vs 1374.69 vs 1570.77 ng/mL·h), and Cl (11.82 vs 14.50 vs 13.01 mL/h) for these groups were lower, but this difference was not statistically significant (P>0.05). These findings suggested that the ABCG2 421 A/A genotype may impact rivaroxaban parameters after a single dose in healthy subjects. This finding must be validated before it is applied in clinical practice.

Biobancos en otorrinolaringología / Biobanks in otolaryngology

Resumen Los biobancos son una innovadora herramienta biotecnológica y un recurso fundamental para el continuo avance en la investigación científica biomédica, y para el advenimiento de la medicina de precisión. Se han desarrollado de forma exponencial durante los últimos 20 años en el mundo, como también a nivel de nuestro país, con la creación de 10 biobancos desde el año 2004. En ellos se almacenan y organizan distintos tipos de muestras biológicas, asociadas a datos epidemiológicos y genéticos de donantes voluntarios. Todos los especímenes almacenados deben ser preservados con estándares de calidad garantizados, a modo de asegurar trazabilidad, integridad y calidad de las muestras. A pesar de que la mantención de un biobanco puede significar altos costos, a fin de cuentas, abaratan costos de los estudios clínicos, dado que es precisamente el biobanco quien se encarga de la obtención de datos y muestras clínicas confiables, permitiendo realizar múltiples estudios a partir de las mismas muestras. A través de este proceso, los biobancos permiten mantener una fuente confiable de recur-sos para la investigación en diversas áreas de la medicina, dentro de ellas la otorrinolaringología. En otorrinolaringología, los biobancos han significado un gran avance, facilitando la investigación en relación con hipoacusia, presbiacusia y tinnitus, así como en el área oncológica. En un futuro, se espera que la comunidad científica haga uso de este recurso, pudiendo expandir su utilidad no solo en el área médica, sino también en otras profesiones de la salud, maximizando así su gigantesco potencial.

Abstract Biobanks are novel biotechnological tools and a fundamental resource for the constant development of biomedical research, as much as for the growing practice of precision medicine. They have proliferated worldwide over the past 20 years and Chile has not been left behind with the creation of 10 bio-banks since 2004. Biobanks store and organize different types of biological samples associated with epidemiological and genetic data from volunteer donors. These samples are stored and preserved under guaranteed quality standards to ensure their traceability, integrity, and quality. Even though the price of maintaining a biobank may seem high, after all, they reduce the costs of research, since biobanks are responsible of the acquisition and storage of data and samples, allowing the performance of multiple studies from the same collection of specimens. In this direction, biobanks grant a constant source of well-founded scientific material for investigation in a wide range of medical fields, such as otolaryngology among them. In otolaryngology, the biobanks have meant a great improvement, facilitating investigations related to deafness, presbycusis, tinnitus and oncology. In the future we hope the scientific community will expand the use this innovative tool over a broader medical field and towards other health-related professions, making the most of its enormous potential.

Performance of a real time PCR for leishmaniasis dignosis using a L. (L.) infantum hypothetical protein as target in canine samples

Visceral leishmaniasis represents an important public health issue in different parts of the world, requiring that measures be put in place to control the spread of the disease worldwide. The canine leishmaniasis diagnosis is not easy based on clinical signs, since dogs may not develop the infection with recognizable signs. Thus, the laboratorial diagnosis is essential to ascertain the incidence and prevalence of canine leishmaniasis especially in areas with major control efforts. Although, the diagnosis can be performed by the use of different approaches, the molecular methods such as PCR have become an indispensable tool for leishmaniases diagnosis. A TaqMan assay for real-time PCR (Linj31-qPCR) was developed to determine the parasite occurrence in clinical cases of leishmaniasis. The assay targets an L. (L.) infantum hypothetical protein region. The specificity of the assay was verified by using Leishmania World Health Organization reference strains including parasites belonging to subgenus L. (Leishmania), subgenus L. (Viannia), other Leishmania species and Trypanosoma cruzi. The sensitivity was verified by using isolates of L. (L.) amazonensis and L. (L.) infantum. The usefulness of the assay for diagnosis was ascertained by testing 277 samples from dogs in regions endemic for visceral and/or cutaneous leishmaniasis and from regions in which leishmaniasis was not endemic in São Paulo State, Brazil. Diagnosis of canine visceral leishmaniasis (CVL) was determined on these animals by conventional PCR and three serological tests. The dog samples were divided into four groups. I, dogs with CVL (n = 101); II, dogs with other diseases and without CVL (n = 97); III, dogs with American cutaneous leishmaniasis (n = 7), and, IV, dogs without CVL (n = 72) from areas where leishmaniasis was not endemic as control group. Results indicated that Linj31-qPCR was able to identify parasites belonging to subgenus L. (Leishmania) with no cross-amplification with other parasite subgenera. The Linj31-qPCR detected Leishmania parasites DNA in 98% of samples from Group I. In conclusion this methodology can be used as routine diagnostic tools to detect parasites from subgenus Leishmania.

Critical analysis of autoregressive and fast Fourier transform markers of cardiovascular variability in rats and humans

The autonomic nervous system plays an important role in physiological and pathological conditions, and has been extensively evaluated by parametric and non-parametric spectral analysis. To compare the results obtained with fast Fourier transform (FFT) and the autoregressive (AR) method, we performed a comprehensive comparative study using data from humans and rats during pharmacological blockade (in rats), a postural test (in humans), and in the hypertensive state (in both humans and rats). Although postural hypotension in humans induced an increase in normalized low-frequency (LFnu) of systolic blood pressure, the increase in the ratio was detected only by AR. In rats, AR and FFT analysis did not agree for LFnu and high frequency (HFnu) under basal conditions and after vagal blockade. The increase in the LF/HF ratio of the pulse interval, induced by methylatropine, was detected only by FFT. In hypertensive patients, changes in LF and HF for systolic blood pressure were observed only by AR; FFT was able to detect the reduction in both blood pressure variance and total power. In hypertensive rats, AR presented different values of variance and total power for systolic blood pressure. Moreover, AR and FFT presented discordant results for LF, LFnu, HF, LF/HF ratio, and total power for pulse interval. We provide evidence for disagreement in 23 percent of the indices of blood pressure and heart rate variability in humans and 67 percent discordance in rats when these variables are evaluated by AR and FFT under physiological and pathological conditions. The overall disagreement between AR and FFT in this study was 43 percent.

Increased sympathetic activity in normotensive offspring of malignant hypertensive parents compared to offspring of normotensive parents

Malignant hypertension seems to be the consequence of very high blood pressure. Furthermore, an increase in sympathetic and renin-angiotensin system activity is considered to be the main mechanisms producing malignant hypertension. In the present study, 10 offspring of malignant hypertensive (OMH) parents (age 28 ± 5 years, 7 males, 3 females, 2 white and 8 non-white) and 10 offspring of normotensive (ONT) parents (age 28 ± 6 years, 2 males, 8 females, 3 white and 7 non-white) were evaluated. The OMH group had significantly higher (P < 0.05) casual blood pressure (125 ± 10/81 ± 5 mmHg) compared with ONT (99 ± 13/67 ± 5 mmHg). The increase in blood pressure was greater in OMH (Ä SBP = 17 ± 2 vs Ä SBP = 9 ± 1 mmHg in ONT) during cold pressor testing, but they had a lower increase in heart rate (Ä HR = 13 ± 2 vs Ä HR = 20 ± 3 bpm in ONT) during isometric exercise (handgrip test). Sympathetic activity, measured by microneurography, was significantly higher (P < 0.05) before exercise in OMH (17 ± 6 vs 11 ± 4 burst/min in ONT) and exhibited a greater increase (Ä = 18 ± 10 vs Ä = 8 ± 3 burst/min in ONT) during isometric exercise. This study showed increased sympathetic activity in OMH before exercise and a greater response during isometric exercise, suggesting an autonomic abnormality before exercise and a greater sympathetic response to physical stress in OMH compared to ONT.

Efectos preventivos de la inmunoterapia sublingual en niños: un estudio abierto, aleatorizado y controlado / Preventive effects of sublingual immunotherapy in childhood: an open randomized controlled study

Objetivos. Evaluar los efectos clínicos y preventivos de la inmunoterapia sublingual (SLIT) con respecto a la aparición de asma persistente, nuevas sensibilizaciones, síntomas clínicos e hiperreactividad bronquial (HRB). Los objetivos secundarios fueron: evaluar la magnitud del efecto clínico y el efecto sobre la HRB; ver la seguridad y adhesión a la SLIT. Material y métodos: Participaron 216 niños, de ambos sexos, entre 5 y 17 años, pacientes del Hospital Cuasso al Monte, Varese, Italia, con rinitis alérgica de al menos 2 años de evolución, con o sin síntomas de asma intermitente, y con diagnóstico de etiología alérgica confirmado para ácaros, gramíneas, árboles y malezas. Se excluyeron pacientes con asma persistente o VEF1 <80%, uso previo de inmunoterapia, anormalidades anatómicas de las vías aéreas superiores, enfermedades sistémicas crónicas (malignas o autoinmunes) y sensibilizaciones a epitelios y hongos anemófilos. Para los diagnósticos de rinitis y asma se emplearon las guías actuales (ARIA, GINA). Se realizaron prick test con panel estándar de alérgenos relevantes (ALK Abelló), histamina 1% y control negativo al principio y al final del estudio. Las pruebas de función pulmonar consistieron en espirometría computarizada con cabina pletismográfica y prueba de provocación no específica con metacolina con dosis progresivas desde 30 a 1.290 µg, durante el período de máxima exposición alérgenica según sensibilidad de cada paciente, al inicio y al final del estudio. A los pacientes con prueba negativa (descenso del VEFI <20%) se los consederaba con diagnóstico de rinitis exclusivamente. El estudi tuvo un período basal de 1 año de observación y luego una fase de aleatorización de 3 años de tratamiento abierto con dos ramas. Un grupo de pacientes utilizó drogas exclusivamente, y otro grupo drogas más SLIT (con una distribución 1/2).

Pressure and time dependence of the cardiopulmonary reflex response in patients with hypertensive cardiomyopathy

The first minutes of the time course of cardiopulmonary reflex control evoked by lower body negative pressure (LBNP) in patients with hypertensive cardiomyopathy have not been investigated in detail. We studied 15 hypertensive patients with left ventricular dysfunction (LVD) and 15 matched normal controls to observe the time course response of the forearm vascular resistance (FVR) during 3 min of LBNP at -10, -15, and -40 mmHg in unloading the cardiopulmonary receptors. Analysis of the average of 3-min intervals of FVR showed a blunted response of the LVD patients at -10 mmHg (P = 0.03), but a similar response in both groups at -15 and -40 mmHg. However, using a minute-to-minute analysis of the FVR at -15 and -40 mmHg, we observed a similar response in both groups at the 1st min, but a marked decrease of FVR in the LVD group at the 3rd min of LBNP at -15 mmHg (P = 0.017), and -40 mmHg (P = 0.004). Plasma norepinephrine levels were analyzed as another neurohumoral measurement of cardiopulmonary receptor response to LBNP, and showed a blunted response in the LVD group at -10 (P = 0.013), -15 (P = 0.032) and -40 mmHg (P = 0.004). We concluded that the cardiopulmonary reflex response in patients with hypertensive cardiomyopathy is blunted at lower levels of LBNP. However, at higher levels, the cardiopulmonary reflex has a normal initial response that decreases progressively with time. As a consequence of the time-dependent response, the cardiopulmonary reflex response should be measured over small intervals of time in clinical studies.

Autonomic abnormalities demonstrable in young normotensive subjects who are children of hypertensive parents

Although a slightly elevated office blood pressure (BP) has been reported in several studies, little is known about the prolonged resting blood pressure, heart rate (HR) and baroreflex sensitivity (BRS) of prehypertensive subjects with a family history of hypertension. Office blood pressure, prolonged resting (1 h) BP and HR were measured in 25 young normotensives with a positive family history of hypertension (FH+) and 25 young normotensives with a negative family history of hypertension (FH-), matched for age, sex, and body mass index. After BP and HR measurements, blood samples were collected for the determination of norepinephrine, plasma renin activity and aldosterone levels, and baroreflex sensitivity was then tested. Casual BP, prolonged resting BP and heart rate were significantly higher in the FH+ group (119.9 + or - 11.7/78.5 + or - 8.6 mmHg, 137.3 + or - 12.3/74.4 + or - 7.9 mmHg, 68.5 + or - 8.4 bpm) compared to the FH- group (112.9 + or - 11.4/71.2 + or - 8.3 mmHg, 128.0 + or - 11.8/66.5 + or - 7.4 mmHg, 62.1 + or - 6.0 bpm). Plasma norepinephrine level was significantly higher in the FH+ group (220.1 + or - 104.5 pg/ml) than in the FH- group (169.1 + or - 63.3 pg/ml). Baroreflex sensitivity to tachycardia (0.7 + or - 0.3 vs 1.0 + or - 0.5 bpm/mmHg) was depressed in the FH+ group (P<0.05). The FH+ group exhibited higher casual blood pressure, prolonged resting blood pressure, heart rate and plasma norepinephrine levels than the FH- group (P<0.05), suggesting an increased sympathetic tone in these subjects. The reflex tachycardia was depressed in the FH+ group

Reconstrucción de la superficie conjuntival con membrana amniótica posterior a la excisión de pterigión / Amniotic membrane for surface reconstruction posterior at the ptergium excision

Se realiza un estudio prospectivo de cirugía de pterigión primario y recurrente con injerto de membrana amniótica, con el objeto de determinar la tasa de recurrencia y aspecto cosmético final con esta técnica. Se practicaron un total de 79 cirugías en 77 pacientes, 55 pterigión primario y 24 pterigión recurrente, pertenecientes a la consulta de oftalmología del Hospital Municipal "Francisco Antonio Rísquez". Los resultados obtenidos no mostraron diferencia estadísticamente significativa en cuanto a recurrencia según sexo, edad y lateralidad. Se observó una baja tasa de recurrencia, siendo para pterigión primario del 15 por ciento y 29 por ciento para pterigión recurrente, con una diferencia estadísticamente no significativa (x²=2,232.P>0,05). Para el estudio del aspecto postoperatorio final, se agruparon los pacientes en 4 grupos: Grado 1: apariencia normal. Grado 2: presencia de vasos epiesclerales finos en el área escindida que se extiende hasta, pero no más allá del limbo y sin tejido fibroso. Grado 3: presencia de tejido fibroso en el área escindida que no invade córnea. Grado 4: verdadera recurencia con tejido fibrovascular que invade córnea. Al comparar el aspecto final de los pterigión primarios y recurentes por grados, si se encontró diferencia estadísticamente significativa tanto al incluir los grados (x² = 7,99. P= 0,04607), como al comparar aisladamente los grados 3 y 4, (x² = 1,3967.P<0,05). Se comparó adicionalmente, nuestros resultados, con los obtenidos en otros estudios, donde se empleó una técnica similar, y no se encontró diferencia estadísticamente significativa. Nuestro trabajo muestra una técnica de uso reciente que además de presentar resultados excelentes en cuanto a la baja recurrencia y aspecto cosmético, nos permite preservar la conjuntiva ipsi y contralateral en aquellos casos donde se desea mantener su indemnidad. La membrana amniótica proporciona un tejido sustituto de la conjuntiva como injerto para recubrir defectos de la superficie del globo ocular posterior a la excisión de pterigión