High prevalence of non-alcoholic fatty liver disease and metabolic risk factors in Guatemala: A population-based study.

BACKGROUND: There are no data on the prevalence of non-alcoholic fatty liver disease (NAFLD) in general population samples in Guatemala or in other Central American countries. The prevalence and distribution of NAFLD and its associated risk factors were evaluated in a population-based sample of adults in Guatemala. METHODS: Cross-sectional study of 411 men and women 40 years of age or older residing in urban and rural areas of Guatemala. Metabolic outcomes included obesity, central obesity, hypercholesterolemia, diabetes, and metabolic syndrome (MetS). Liver disease outcomes included elevated liver enzymes, elevated Fatty Liver Index (FLI), and elevated FIB-4 score. RESULTS: The overall prevalence of obesity, central obesity, diabetes, and MetS were 30.9, 74.3, 21.6, and 64.2%, respectively. The fully-adjusted prevalence ratios (95% CI) for obesity, central obesity, diabetes, and MetS comparing women to men were 2.83 (1.86-4.30), 1.72 (1.46-2.02), 1.18 (1.03-1.34), and 1.87 (1.53-2.29), respectively. The overall prevalence of elevated liver enzymes (ALT or AST), elevated FLI, and elevated FIB-4 scores were 38.4, 60.1, and 4.1%, respectively. The fully-adjusted prevalence ratios (95% CI) for elevated liver enzymes (either ALT or AST) and elevated FLI score comparing women to men were 2.99 (1.84-4.86) and 1.47 (1.18-1.84), respectively. CONCLUSIONS: The prevalence of metabolic abnormalities and liver outcomes in this general population study was very high. The prevalence of metabolic and liver abnormalities was particularly high among women, an observation that could explain the atypical 1:1 male to female ratio of liver cancer in Guatemala.

Diffusion-Weighted Magnetic Resonance Imaging in Liver Graft Rejection.

OBJECTIVE: The purpose of this study is to evaluate the use of diffusion-weighted magnetic resonance imaging (DWMRI) in the assessment of graft rejection after liver transplantation (LT). METHODS: From June 2017 to January 2018, 32 patients were included in the study with a mean age of 52.3 years. All patients underwent LT. The DWMRI was performed using the apparent diffusion coefficient map and measuring the different b-values (b-400, b-600, b-800, and b-1000). These measurements were compared with the histopathology results. Statistical analysis included t test, analysis of variance, and area under the curve for receiver operating characteristic (ROC). RESULTS: There were 17 patients without rejection and 15 patients with liver graft rejection diagnosed by histopathology. The mean (SD) results between the nonrejection and rejection groups were as follows: b-400 = 1.568 (0.265) vs 1.519 (0.119) (P = .089), b-600 = 1.380 (0.181) vs 1.284 (0.106) (P = .039), b-800 = 1.262 (0.170) vs 1.170 (0.086) (P = .035), b-1000 = 1.109 (0.129) vs 1.098 (0.078) (P = .095); B-values × 10-3 mm2/s. Only b-600 (P = .04) and b-800 (P = .04) values have significant differences between the 2 groups. B-600 showed 90.48% sensitivity and 83.33% specificity (ROC area under the curve = 0.784; P < .001), and b-800 showed 90.38% sensitivity and 83.03% specificity (ROC area under the curve = 0.816; P < .001). The values obtained with the apparent diffusion coefficient in b-800 were clearly differentiated between the mild, moderate, and severe degrees of rejection (P < .001). CONCLUSION: Measurement of b-600 and b-800 values using DWMRI may be used for the diagnosis of graft rejection after LT.

Analysis of the average photon path length between two consecutive reflections from the cavity walls.

In this paper a general theoretical analysis of the average photon path length between two consecutive photon reflections from the cavity walls has been presented. The presented analysis relies only on the energy conservation law and the assumption of the uniform photon distribution within the cavity volume. The obtained general result coincides with the solution previously obtained but under more stringent conditions.

Magnetic Resonance Spectroscopy in Living-Donor Liver Transplantation.

OBJECTIVE: The purpose of this study is to evaluate the accuracy rate of the one breath-hold single voxel hydrogen-1 magnetic resonance spectroscopy (MRS) in comparison with intraoperative biopsy for liver fat quantification in living-donor liver transplantation. MATERIALS AND METHODS: A total of 80 living liver donors participated in this study. Each patient underwent both MRS and intraoperative biopsy for evaluation of liver fatty content. MRS was performed using 1.5-T magnetic resonance imaging and placed in segments 2-4, 5-8, and left lateral segment for each donor. Accuracy was assessed through receiver operating characteristic curve analysis. Sensitivity and specificity of MRS fat fractions were also calculated. RESULTS: Eighty living-donor liver transplantation donors were enrolled in this study. There was no fatty liver in 59 subjects (73.8%), 5% to 10% fatty liver in 17 subjects, 11% to 15% fatty liver in 3 subjects, and >16% fatty liver in 1 subject. MRS fat fraction showed excellent parameters to predict between normal liver and fatty liver groups (1.85% ± 0.98, 8.13% ± 3.52, respectively; P < .0001). Linear regression between MRS fat fraction and pathology grading showed high correlation (R(2) = 0.7092). Pearson correlation revealed high correlation between MRS and pathology results (r = 0.936), poor correlation between body mass index and pathology results (r = 0.390). The sensitivity and specificity for detection of liver steatosis in MRS fat fraction were 95.2% and 98.3%, respectively. CONCLUSION: (1)H MRS fat fraction is a highly precise and accurate method in quantification of hepatic steatosis for the living donor and can be finished in a single breath-hold.

Pharmacokinetic Analysis of Dynamic Contrast-Enhanced Magnetic Resonance Imaging for Distinguishing Hepatocellular Carcinoma From Cholangiocarcinoma in Pre-Liver Transplantation Evaluation.

OBJECTIVE: Liver transplantation for intrahepatic cholangiocarcinoma is notorious for rapid recurrence with poor survival rate postoperatively and has therefore been discontinued in most centers. The purpose of this study is to distinguish hepatocellular carcinoma (HCC) from cholangiocarcinoma in pretransplantation imaging evaluation by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). MATERIALS AND METHODS: From January 2014 to September 2015, 19 patients were included in the study, with a mean age of 62.8 years. All subjects underwent pretransplantation DCE-MRI and surgical excision or core biopsy. The DCE-MRI parameters were measured using the Tofts model 1999. Statistical analysis included nonparametric tests and area under the curve for the receiver operating characteristic. RESULTS: Fourteen HCCs and 5 cholangiocarcinomas were diagnosed by surgical pathology. The mean size of tumor was 6.4 cm (range, 1.5 cm to 13.7 cm). All DCE-MRI parameters were calculated as the ratio between the tumor and normal liver parenchyma and K(trans) (1/min) was used as a distinguishing parameter between the two tumors. K(trans) was higher in the cholangiocarcinoma group (1.89 ± 1.13) than in the HCC group (0.46 ± 0.35). Univariate analysis revealed that K(trans) has a high significant difference (P = .001). The optimal K(trans) value cutoffs were 1 or more (area under the curve = 0.971) for detection of HCCs or cholangiocarcinomas. CONCLUSION: The analysis of DCE-MRI with the kinetic model (Tofts, 1999) presents a new and practical approach indiscrimination of HCC from cholangiocarcinoma for pretransplantation imaging evaluation.

Noncontrast Magnetic Resonance Angiography Using Inflow Sensitive Inversion Recovery Technique for Vascular Evaluation in Pre-liver Transplantation Recipients.

OBJECTIVE: Vascular anatomy is essential in pretransplantation survey. The purpose of this study is to investigate the feasibility and diagnostic performance of inflow sensitive inversion recovery (IFIR) magnetic resonance angiography (MRA) to evaluate the recipient's hepatic vasculature before liver transplantation. MATERIALS AND METHODS: Thirty-one pre-liver transplantation patients underwent both IFIR and conventional contrast-enhanced MRA using a 1.5T MR scanner from December 2012 to December 2014. The contrast-to-noise ratios (CNRs) between liver parenchyma and hepatic vasculature were calculated. The image sets of IFIR and contrast-enhanced MRA were assessed for subjective image quality and depiction of hepatic vasculature on vessel-to-vessel basis by two independent radiologists. RESULTS: The quantitative results of CNR for hepatic arteries on IFIR were significantly lower than contrast-enhanced MRA, whereas CNR for portal veins and inferior vena cava on IFIR were significantly higher than contrast-enhanced MRA. For subjective assessment of image quality, the overall agreement of scores of IFIR and contrast-enhanced MRA was substantial (kappa values ranged from 0.650 to 0.767). There was no significant difference in the image quality for portal veins between IFIR and contrast-enhanced MRA. The quality scores of IFIR were significantly lower than contrast-enhanced MRA for hepatic arteries. For inferior vena cava evaluation, the scores of IFIR were significantly higher than contrast-enhanced MRA. CONCLUSION: IFIR MRA is a reproducible and noninvasive tool to assess the hepatic vasculature that can provide adequate to good image quality. In pre-liver transplantation patients, IFIR MRA becomes even more useful if contrast medium is a contraindication due to impaired renal and liver functions.

Combined Hepatocellular Carcinoma and Cholangiocarcinoma: Diagnosis and Prognosis After Resection or Transplantation.

BACKGROUND: Primary liver malignancy is the leading cause of cancer death worldwide, with hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) representing the majority. Combined HCC-CC, in contrast, accounts for less than 5% of these liver cancers and has not been clearly characterized by imaging, making diagnosis and management difficult. MATERIALS AND METHODS: This retrospective study investigated 32 patients with early-stage combined HCC-CC tumor who underwent hepatectomy (n = 24) or liver transplantation (n = 8). Preoperative imaging and pathologic reports were retrospectively reviewed and correlated. Survival and recurrence rates were then analyzed. RESULTS: Twelve patients with more than 50% CC component showed typical CC enhancement, whereas 17 patients with less than 50% CC component exhibited typical HCC enhancement. Those with equivocal imaging findings resulted near equal tumor component. The majority demonstrated either heterogeneous or peripheral enhancement. Considering the major tumor component, 66% of the images were consistent with histopathology. The over-all 3-year recurrent rate was 59%, with a mean time to recurrence of about 7 months. The 3-year survival rate of combined tumor after hepatectomy was 76% and after transplant was 75%, regardless of major tumor component. However, patients with more than 50% CC component showed a decrease in 3-year survival rate to 50% when transplantation was performed. CONCLUSION: The overall survival rate for combined tumor after either hepatectomy or transplantation seems to be satisfactory but carries a high risk of recurrent when compared to pure HCC. On the other hand, a major CC component tumor after transplantation is associated with poor survival outcome; thus, liver transplantation has no role and is not a good management option.

Photometry-based estimation of the total number of stars in the Universe.

A novel photometry-based estimation of the total number of stars in the Universe is presented. The estimation method is based on the energy conservation law and actual measurements of the extragalactic background light levels. By assuming that every radiated photon is kept within the Universe volume, i.e., by approximating the Universe as an integrating cavity without losses, the total number of stars in the Universe of about 6×1022 has been obtained.

Paciente con síndrome cardiorrenal terminal que no acepta una limitación de esfuerzo terapéutico. Análisis del problema ético-clínico / Terminal cardiorenal syndrome patient not willing to accept a limitation of therapeutic effort. Ethical and clinical problem's analisys

La indicación de limitación de esfuerzo terapéutico en un caso de síndrome cardiorrenal planteó un problema ético en un paciente que solicita ultrafiltración, medida considerada fútil por sus médicos. La consulta al comité de ética asistencial, el análisis ético-clínico y el proceso de comunicación ayudaron a tomar las mejores decisiones

The limitation of therapeutic effort in a cardiorenal syndrome patient asking for ultrafiltration led to an ethical problem. An ethical care committee consultation and communication process helped in making the correct decisions

High-resolution wide-dynamic range electronically scanned white-light interferometry.

A novel high-resolution wide-dynamic range electronically scanned white-light interferometry-based interrogation technique is presented. By using off-the-shelf optical components, this technique is capable of reaching a subnanometer resolution. The technique relies on a simple optical setup in which the wedge and camera axes are mutually inclined for a very small angle in the horizontal plane and two-dimensional fringe pattern analysis. Resolution below 0.3 nm and dynamic range of 106 dB have been achieved with a signal-to-noise ratio lower than 25 dB.

Spin-1 Hopfield model under a random field.

The goal of the present work is to investigate the role of trivial disorder and nontrivial disorder in the three-state Hopfield model under a Gaussian random field. In order to control the nontrivial disorder, the Hebb interaction is used. This provides a way to control the system frustration by means of the parameter a=p/N, varying from trivial randomness to a highly frustrated regime, in the thermodynamic limit. We performed the thermodynamic analysis using the one-step replica-symmetry-breaking mean field theory to obtain the order parameters and phase diagrams for several strengths of a, the anisotropy constant, and the random field.

Robust white-light interferometric sensing system for fast displacement measurement.

A robust white-light interferometric sensing system for fast displacement measurement is presented. In order to increase the speed of the sensing system in comparison with the standard realization based on the postprocessing of the captured interferometric signal, a real-time algorithm based on the modified centroid algorithm has been implemented. The modified centroid algorithm generates the error signal that is proportional to the interferometer optical path difference (OPD) during every scan of the used white-light source coherence zone. In order to keep zero OPD, an amplified version of the error signal has been brought to the input of the piezo bimorph actuator (PBA) that on the other side serves for the fast coherence zone scan. In this way the PBA tracks the position of the object whose displacement is to be measured. Therefore, the voltage signal at the PBA input is proportional to the measured displacement. The realized sensing system has an overall bandwidth of almost 10 Hz, where the sensor full scale range of 200 µm has been measured with a resolution of 3 nm.

Meta-analysis: vitamin D and non-alcoholic fatty liver disease.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent condition. Emerging evidence suggests that vitamin D may play a role in the pathogenesis of NAFLD. AIM: To review systematically the association between vitamin D levels, measured as serum 25-hydroxy vitamin D [25(OH)D], and NAFLD. METHODS: We used PubMed and EMBASE databases to identify all studies that assessed the association between vitamin D and NAFLD up until 22 April 2013, without language restrictions. We included studies that compared vitamin D levels between NAFLD cases and controls and also those that compared the odds of vitamin D deficiency by NAFLD status. Pooled standardised differences and odds ratios were calculated using an inverse variance method. RESULTS: Seventeen cross-sectional and case-control studies have evaluated the association between vitamin D and NAFLD. NAFLD was diagnosed using biopsy (4 studies), ultrasound or CT (10 studies) and liver enzymes (3 studies). Nine studies provided data for a quantitative meta-analysis. Compared to controls, NAFLD patients had 0.36 ng/mL (95% CI: 0.32, 0.40 ng/mL) lower levels of 25(OH)D and were 1.26 times more likely to be vitamin D deficient (OR 1.26, 95% CI: 1.17, 1.35). CONCLUSIONS: NAFLD patients have decreased serum 25(OH)D concentrations, suggesting that vitamin D may play a role in the development of NAFLD. The directionality of this association cannot be determined from cross-sectional studies. Demonstration of a causal role of hypovitaminosis D in NAFLD development in future studies could have important therapeutic implications.

Liver enzymes, race, gender and diabetes risk: the Atherosclerosis Risk in Communities (ARIC) Study.

AIMS: To examine the associations of the liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase(AST), and gamma-glutamyl transferase (GGT) with diabetes risk and to determine whether associations differ by race and/or gender. We hypothesized that all liver enzymes would be associated with diabetes risk and that associations would differ by race and gender. METHODS: Prospective cohort of 7495 white and 1842 black participants without diabetes in the Atherosclerosis Risk in Communities Study. Poisson and Cox models adjusted for demographic, socio-behavioural, and metabolic and health-related factors were used. RESULTS: During a median of 12 years of follow-up, 2182 incident cases of diabetes occurred. Higher liver enzyme levels were independently associated with diabetes risk: adjusted hazard ratios (95% confidence intervals) were 1.68 (1.49-1.89), 1.16 (1.02-1.31) and 1.95 (1.70-2.24) comparing the highest with the lowest quartiles of ALT, AST, and GGT, respectively. Gamma-Glutamyl transferase was most strongly related to diabetes risk, even at levels considered within the normal range (≤ 60 U/l) in clinical practice. Adjusted incidence rates by quartiles of liver enzymes were similar by gender but higher in black versus white participants. Nonetheless, relative associations of ALT, AST, and GGT with diabetes were similar by race (P for interactions > 0.05). CONCLUSIONS: Compared with ALT and AST, GGT was more strongly associated with diabetes risk. Our findings suggest that abnormalities in liver enzymes precede the diagnosis of diabetes by many years and that individuals with elevated liver enzymes, even within the normal range as defined in clinical practice, are at high risk for diabetes.

High-speed and high-sensitivity displacement measurement with phase-locked low-coherence interferometry.

A novel high-speed and high-sensitivity displacement measurement sensing system, based on the phase-locked low-coherence interferometry, is presented. The sensing system is realized by comprising the Michelson fiber-optic interferometer. In order to obtain quadrature signals at the interferometer outputs, a 3×3 fused silica fiber-optic directional coupler is used. Therefore, the usage of the interferometer phase modulation as well as the usage of the lock-in amplification has been avoided. In this way, the speed of such a realized sensing system is significantly increased in comparison with the standard phase-locked interferometric systems that can be found elsewhere in the literature. The bandwidth of the realized sensing system is limited by the first resonance frequency of the used piezo actuator to 4.6 kHz. The estimated noise floor in the displacement measurement is approximately 180 pm/√Hz.

Inverse freezing in the Ghatak-Sherrington model with a random field.

The present work studies the Ghatak-Sherrington (GS) model in the presence of a magnetic random field (RF). Previous results obtained from the GS model without a RF suggest that disorder and frustration are the key ingredients to produce spontaneous inverse freezing (IF). However, in this model, the effects of disorder and frustration always appear combined. In that sense, the introduction of RF allows us to study the IF under the effects of a disorder which is not a source of frustration. The problem is solved within the one step replica symmetry approximation. The results show that the first order transition between the spin glass and the paramagnetic phases, which is related to the IF for a certain range of crystal field D, is gradually suppressed when the RF is increased.

Quadrant photodetector sensitivity.

A quantitative theoretical analysis of the quadrant photodetector (QPD) sensitivity in position measurement is presented. The Gaussian light spot irradiance distribution on the QPD surface was assumed to meet most of the real-life applications of this sensor. As the result of the mathematical treatment of the problem, we obtained, in a closed form, the sensitivity function versus the ratio of the light spot 1/e radius and the QPD radius. The obtained result is valid for the full range of the ratios. To check the influence of the finite light spot radius on the interaxis cross talk and linearity, we also performed a mathematical analysis to quantitatively measure these types of errors. An optimal range of the ratio of light spot radius and QPD radius has been found to simultaneously achieve low interaxis cross talk and high linearity of the sensor.

Morbilidad dermatológica en interconsultas de pacientes hospitalizados en el Complejo Asistencial Barros Luco / Dermatologic morbidity in consultations of patients at the Complejo Asistencial Barros Luco

Las patologías dermatológicas comunes y los signos cutáneos de enfermedades sistémicas están habitualmente presentes en los pacientes hospitalizados. El objetivo de este estudio fue analizar las interconsultas derivadas al Servicio de Dermatología y evaluar el perfil del paciente, el patrón de referencia y la precisión diagnóstica de los médicos no dermatólogos. Se realizó un estudio retrospectivo, se revisaron todas las interconsultas de pacientes hospitalizados durante el período comprendido entre abril del 2006 y diciembre del 2009 en el Complejo Asistencial Barros Luco. En 1.009 interconsultas se analizaron las variables de edad, género, fecha de derivación, Servicios Clínicos y la concordancia diagnóstica. La edad media de los pacientes derivados fue de 53,73 años (+/- -19.24 SD) con un 45,39 por ciento de mujeres y 56,61 por ciento de hombres. Los Servicios Clínicos con mayor frecuencia de solicitudes de interconsultas fueros: Hospital Infecccioso (37,80 por ciento), Medicina Interna (27,50 por ciento), Neurología (6,90 por ciento) y UCI (6,30 por ciento). La concordancia diagnóstica general fue de 48,75 por ciento y varía por cada grupo de enfermedades dermatológicas (inflamatorias: 54,90 por ciento, infecciosas: 22,25 por ciento; neoplasias benignas y malignas: 13,8 por ciento y otros diagnósticos: 9,07 por ciento). El perfil de interconsultas es diferente al de los pacientes ambulatorios, el diagnóstico específico que presentó el mayor porcentaje de derivaciones fueron las reacciones adversas medicamentosas, lo que se explica por la gran cantidad de fármacos usados a nivel hospitalario a diferencia del nivel ambulatorio donde éstas no son un diagnóstico significante. La concordancia diagnóstica respecto al diagnóstico dermatológico no supera el 50 por ciento en forma global y la tumoral solo presenta un 42,99 por ciento de asertividad, por lo que sería importante mejorar la educación dermatológica de pregrado especialmente en patologías de mayor...

Common dermatologic conditions and skin signs of systemic diseases are routinely present in hospitalized patients. The objective of this study was to analize the patient profile and the referral pattern of the in - patient dermatology consultation and evaluate the diagnostic accuracy of non dermatologist. This was retrospective study reviewing all inpatient referrals during a period (April 2006. December 2009) at the Barros Luco Hospital. 1009 dermatological consultations were analized by age, sex, date, clinical service and diagnostic correlation. The average age of the patients was 53.73 years old (+/-19.24DS) with a 45.39 percent of female and 56.61 percent of males. The Clinical services that most require consultations were infetious diseases (37.80 percent), internal medicine (27.50 percent), Neurology (6.90 percent) and ICU (6.30 percent). The total correlation diagnosis was 48.75 percent and this percentage was analized per dermatological disease (inflammatory 54.90 percent, infectious diseases 22.25 percent, benign and malignant neoplasias 13.8 percent and other diagnosis 9.07 percent). The inpatients consultation profile is different from the outpatient, the specific diagnosis that had the highest percentage of referrals were "adverse drug reactions" which can be explained by the large number of drugs used the hospital level opposed to an outpatient setting where adverse drug reactions do not represent a significant diagnosis. The diagnostic correlation was less than 50 percent globally compared with the dermatologic diagnosis; in tumors a 42.99 percent of concordance was found. It would be important to improve undergraduate education, especially in the most important dermatological diseases.

XV-2c/KM19 haplotypes analysis of cystic fibrosis patients from western Mexico.

The analysis of polymorphic markers within or closely linked to the cystic fibrosis transmembrane regulator (CFTR) gene is useful as a molecular tool for carrier detection of known and unknown mutations. To establish the association between mutations in the CFTR gene in western Mexican cystic fibrosis (CF) patients, the distribution of XV2c/KM19 haplotypes was analyzed by PCR and restriction enzyme digestion in 384 chromosomes from 74 CF patients, their unaffected parents, and normal subjects. The haplotype analysis revealed that haplotype B was present in 71.9% of CF chromosomes compared to 0% of non-CF chromosomes. The F508del and G542X mutations were strongly associated with haplotype B (96.7% and 100% of chromosomes, respectively). The haplotype distribution of the CF chromosomes carrying other CFTR mutations had a more heterogeneous background. Our results show that haplotype B is associated with CFTR mutations. Therefore, haplotype analysis is a suitable alternate strategy for screening CF patients with a heterogeneous clinical picture from populations with a high molecular heterogeneity where carrier detection programs are not available. In addition, it may be a helpful diagnostic tool for genetic counseling and carrier detection in the relatives of CF patients and in couples who are planning to have children.