Genetic testing in focal segmental glomerulosclerosis: in whom and when?

Background: Genetic causes are increasingly recognized in patients with focal segmental glomerulosclerosis (FSGS), but it remains unclear which patients should undergo genetic study. Our objective was to determine the frequency and distribution of genetic variants in steroid-resistant nephrotic syndrome FSGS (SRNS-FSGS) and in FSGS of undetermined cause (FSGS-UC). Methods: We performed targeted exome sequencing of 84 genes associated with glomerulopathy in patients with adult-onset SRNS-FSGS or FSGS-UC after ruling out secondary causes. Results: Seventy-six patients met the study criteria; 24 presented with SRNS-FSGS and 52 with FSGS-UC. We detected FSGS-related disease-causing variants in 27/76 patients (35.5%). There were no differences between genetic and non-genetic causes in age, proteinuria, glomerular filtration rate, serum albumin, body mass index, hypertension, diabetes or family history. Hematuria was more prevalent among patients with genetic causes. We found 19 pathogenic variants in COL4A3-5 genes in 16 (29.3%) patients. NPHS2 mutations were identified in 6 (16.2%) patients. The remaining cases had variants affecting INF2, OCRL, ACTN4 genes or APOL1 high-risk alleles. FSGS-related genetic variants were more common in SRNS-FSGS than in FSGS-UC (41.7% vs 32.7%). Four SRNS-FSGS patients presented with NPHS2 disease-causing variants. COL4A variants were the most prevalent finding in FSGS-UC patients, with 12 patients carrying disease-causing variants in these genes. Conclusions: FSGS-related variants were detected in a substantial number of patients with SRNS-FSGS or FSGS-UC, regardless of age of onset of disease or the patient's family history. In our experience, genetic testing should be performed in routine clinical practice for the diagnosis of this group of patients.

Combining pharmacokinetic and electrophysiological models for early prediction of drug-induced arrhythmogenicity.

BACKGROUND AND OBJECTIVE: In silico methods are gaining attention for predicting drug-induced Torsade de Pointes (TdP) in different stages of drug development. However, many computational models tended not to account for inter-individual response variability due to demographic covariates, such as sex, or physiologic covariates, such as renal function, which may be crucial when predicting TdP. This study aims to compare the effects of drugs in male and female populations with normal and impaired renal function using in silico methods. METHODS: Pharmacokinetic models considering sex and renal function as covariates were implemented from data published in pharmacokinetic studies. Drug effects were simulated using an electrophysiologically calibrated population of cellular models of 300 males and 300 females. The population of models was built by modifying the endocardial action potential model published by O'Hara et al. (2011) according to the experimentally measured gene expression levels of 12 ion channels. RESULTS: Fifteen pharmacokinetic models for CiPA drugs were implemented and validated in this study. Eight pharmacokinetic models included the effect of renal function and four the effect of sex. The mean difference in action potential duration (APD) between male and female populations was 24.9 ms (p<0.05). Our simulations indicated that women with impaired renal function were particularly susceptible to drug-induced arrhythmias, whereas healthy men were less prone to TdP. Differences between patient groups were more pronounced for high TdP-risk drugs. The proposed in silico tool also revealed that individuals with impaired renal function, electrophysiologically simulated with hyperkalemia (extracellular potassium concentration [K+]o = 7 mM) exhibited less pronounced APD prolongation than individuals with normal potassium levels. The pharmacokinetic/electrophysiological framework was used to determine the maximum safe dose of dofetilide in different patient groups. As a proof of concept, 3D simulations were also run for dofetilide obtaining QT prolongation in accordance with previously reported clinical values. CONCLUSIONS: This study presents a novel methodology that combines pharmacokinetic and electrophysiological models to incorporate the effects of sex and renal function into in silico drug simulations and highlights their impact on TdP-risk assessment. Furthermore, it may also help inform maximum dose regimens that ensure TdP-related safety in a specific sub-population of patients.

Insights from an electro-mechanical heart failure cell model: Role of SERCA enhancement on arrhythmogenesis and myocyte contraction.

BACKGROUND AND OBJECTIVE: Structural and electrical remodeling in heart failure predisposes the heart to ventricular arrhythmias. Computer modeling approaches, used to complement experimental results, can provide a more mechanistic knowledge of the biophysical phenomena underlying cardiac pathologies. Indeed, previous in-silico studies have improved the understanding of the electrical correlates of heart failure involved in arrhythmogenesis; however, information on the crosstalk between electrical activity, intracellular Ca2+ and contraction is still incomplete. This study aims to investigate the electro-mechanical behavior of virtual failing human ventricular myocytes to help in the development of therapies, which should ideally target pump failure and arrhythmias at the same time. METHODS: We implemented characteristic remodeling of heart failure with reduced ejection fraction by including reported changes in ionic conductances, sarcomere function and cell structure (e.g. T-tubules disarray). Model parametrization was based on published experimental data and the outcome of simulations was validated against experimentally observed patterns. We focused on two aspects of myocardial dysfunction central in heart failure: altered force-frequency relationship and susceptibility to arrhythmogenic early afterdepolarizations. Because biological variability is a major problem in the generalization of in-silico findings based on a unique set of model parameters, we generated and evaluated a population of models. RESULTS: The population-based approach is crucial in robust identification of parameters at the core of abnormalities and in generalizing the outcome of their correction. As compared to non-failing ones, failing myocytes had prolonged repolarization, a higher incidence of early afterdepolarizations, reduced contraction and a shallower force-frequency relationship, all features peculiar of heart failure. Component analysis applied to the model population identified reduced SERCA function as a relevant contributor to most of these derangements, which were largely reverted or diminished by restoration of SERCA function alone. CONCLUSIONS: These simulated results encourage the development of strategies comprising SERCA stimulation and highlight the need to evaluate both electrical and mechanical outcomes.

Efectos del ultrasonido externo sobre el panículo adiposo. Modelo porcino experimental / Effects of external ultrasound on the adipose panicle. Experimental pig model

INTRODUCCIÓN Y OBJETIVO: El ultrasonido (US) externo o percutáneo, ampliamente utilizado, ocasiona diferentes efectos histológicos dependiendo de la frecuencia, intensidad, amplitud de onda, tiempo de aplicación y de los tejidos a través de los cuales curse. Se ha utilizado con diferentes propósitos, entre otros para facilitar la liposucción y mejorar sus resultados; sin embargo, hasta donde hemos podido revisar, no hay reportes que relacionen las frecuencias del US percutáneo y el lapso de su aplicación con los cambios descritos en el panículo adiposo. El objetivo del presente estudio es establecer parámetros de frecuencia y tiempos de aplicación del US externo para uniformar criterios en base al análisis histológico de los cambios que ocasiona al panículo adiposo y a los adipocitos. MATERIAL Y MÉTODO: Estudio descriptivo, comparativo, abierto, experimental, prospectivo y longitudinal, en 59 fragmentos de tejido adiposo tomados de cerdos adultos. Cinco fragmentos fueron preservados como control; los 54 restantes fueron sometidos a US directo sobre cada fragmento, con diferentes parámetros de tiempo (5, 10 y 15 minutos) y diferentes frecuencias (baja- 1.1 Hz, media- 2.4 Hz y alta- 3.9 Hz). Fueron procesados en 2 formas (parafina y congelación) y teñidos con 2 técnicas (hematoxilina/eosina y rojo oleoso). En cada laminilla se observaron 10 campos. RESULTADOS: En los fragmentos de control observamos tejido adiposo maduro normal. En los sometidos a US, dependiendo de la frecuencia y el tiempo aplicado, observamos edema intersticial, desarreglo de su arquitectura, lisis de la membrana de los adipocitos e infiltrado inflamatorio, en diversos porcentajes, que calificamos en grados. Así en los fragmentos expuestos durante 5 minutos a frecuencia media hubo lisis leve (10%), igual que en los expuestos 10 minutos a frecuencia baja. En los expuestos 10 minutos a frecuencia media la lisis fue de leve a moderada (10-20%), semejante a la observada con frecuencia baja durante 15 minutos. Aplicando US durante 15 minutos con frecuencia baja la respuesta fue de leve a moderada (10-20%), con frecuencia media fue de moderada a severa (20-30%) y con frecuencia alta fue francamente severa (30%). CONCLUSIONES: La aplicación de US externo ocasiona lisis de los adipocitos y evidentes desarreglos en la arquitectura del tejido adiposo. Aplicarlo con frecuencias menores requiere periodos más largos para lograr los mismos efectos. Con frecuencias mayores se logran los cambios en menos tiempo. El empleo de frecuencias de 2.4 a 3.9 Hz ocasiona cambios evidentes, con amplio margen de seguridad

BACKGROUND AND OBJECTIVE: External or percutaneous ultrasound (US) widely used, causes different histological effects depending on the frequency, intensity, wave amplitude, application time and the tissues through which it passes. It has been used for different purposes, among others, to facilitate liposuction and improve its results; however, as far as we have been able to review, there are no reports that relate the frequencies of the percutaneous US and the period of its application with the changes described in the adipose tissue. Our aim is to establish frequency parameters and application times of the external US to standardize criteria, based on the histological analysis of the changes it causes to the adipose panniculus and to the adipocytes. METHODS: A descriptive, comparative, open, experimental, prospective and longitudinal study was carried out in 59 fragments of adipose tissue taken from adult pigs. Fifty-four were subjected to US applied directly to each fragment, with different time parameters (5, 10 and 15 minutes) and different frequencies (low-1.1 Hz, medium-2.4 Hz and high-3.9 Hz). Five fragments were preserved as a control. Processed in 2 ways (paraffin and freezing) and stained with 2 techniques (hematoxylin/eosin and oil red). In each lamella 10 fields were observed. RESULTS: Normal mature adipose tissue was observed in the control fragments. In those undergoing US, depending on the frequency and time applied, interstitial edema, disordered architecture, presence of inflammatory infiltrate and lysis of adipocyte membranes were observed, in various percentages that we qualified in degrees. Thus, in the fragments exposed for 5 minutes at medium frequency, mild lysis was observed (10%), In those exposed for 10 minutes at medium frequency, lysis was mild to moderate ( 10-20%), similar to that observed with low frequency for 15 minutes. Applying US for 15 minutes with low frequency, the response was mild to moderate (10-20%) with medium frequency of moderate to severe (20-30%) and with high frequency it was frankly severe (30%). CONCLUSIONS: The application of external US causes lysis of the adipocytes and evident disorders in the adipose tissue architecture. Applying it with lower frequencies requires longer periods to achieve the same effects. With higher frequencies the same changes are achieved in less time. The use of frequencies from 2.4 to 3.9 Hz causes obvious changes, with a wide margin of safety

Colestasis por deficiencia de 3β-Δ5-C27-hidroxiesteroide deshidrogenasa en un paciente con alteración en la síntesis de ácidos biliares / Cholestasis due to deficiency of 3β-Δ5-C27-hydroxysteroid dehydrogenase in a patient with altered bile acid synthesis

Resumen: Introducción: Los errores innatos en la síntesis de ácidos biliares son un grupo de defectos genéticos que representan del 1 al 2% de las enfermedades colestásicas crónicas en lactantes, niños y adolescentes. La deficiencia de 3β-Δ5-C27-hidroxiesteroide oxidoreductasa (3β-HSDH) es el defecto más comúnmente reportado. El cuadro clínico característico consiste en hepatitis neonatal, hepatomegalia, esplenomegalia, malabsorción, desnutrición y enfermedad hepática de aparición tardía. Caso clínico: Lactante masculino con antecedente de ictericia en escleras a los 4 meses que se resolvió espontáneamente; posteriormente, a los 18 meses, presentó enfermedad colestásica. Durante su abordaje se documentó gamma-glutamil transpeptidasa normal, hallazgo que es altamente sugestivo de alteración en la síntesis de ácidos biliares. El diagnóstico se realizó con espectrometría de masas en orina. Se inició tratamiento con ácido cólico oral, y presentó mejoría inmediata. Conclusiones: El resultado en los ácidos biliares urinarios es definitivo para el defecto genético y consistente con mutaciones homocigotas en el gen HSD3B7. Este padecimiento constituye un diagnóstico de exclusión en las enfermedades colestásicas de la infancia, particularmente el hallazgo de gamma-glutamil transpeptidasa normal o levemente aumentada, y responde adecuadamente al tratamiento oral, por lo que debe identificarse de forma temprana.

Abstract: Background: Inborn errors in bile acid synthesis are a group of genetic defects accounting for 1 to 2% of chronic cholestatic diseases in infants, children and adolescents. Deficiency of 3β-Δ5-C27-hydroxysteroid dehydrogenase (3β-HSDH) is the most common defect in this disease. Clinical features consist of neonatal hepatitis, hepatomegaly, splenomegaly, malabsorption, malnutrition, and late-onset liver disease. Case report: A male infant who presented jaundice in sclera at 4 months that resolved spontaneously, later presented cholestatic disease at 18 months. During his approach, normal gamma-glutamyl transpeptidase was documented, a finding that is highly suggestive of alteration in the synthesis of bile acids. The diagnosis was made using urine mass spectrometry. Oral colic acid treatment was started, presenting immediate improvement. Conclusions: The result in urinary bile acids is definitive for the genetic defect and consistent with homozygous mutations in the HSD3B7 gene. This condition is a diagnosis of exclusion in childhood cholestatic diseases, particularly in the presence of normal or mildly enlarged gamma-glutamyl transpeptidase, and responds adequately to oral treatment; it should be identified early.

Exoftalmos e hiperparatiroidismo / Exophthalmos and hyperparathyroidism

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Correction: Stability of thin film glasses of toluene and ethylbenzene formed by vapor deposition: an in situ nanocalorimetric study.

Correction for 'Stability of thin film glasses of toluene and ethylbenzene formed by vapor deposition: an in situ nanocalorimetric study' by Edgar Leon-Gutierrez et al., Phys. Chem. Chem. Phys., 2010, 12, 14693-14698.

Evaluation of growth front velocity in ultrastable glasses of indomethacin over a wide temperature interval.

Ultrastable thin film glasses transform into supercooled liquid via propagating fronts starting from the surface and/or interfaces. In this paper, we analyze the consequences of this mechanism in the interpretation of specific heat curves of ultrastable glasses of indomethacin for samples with varying thickness from 20 nm up to several microns. We demonstrate that ultrastable films above 20 nm have identical fictive temperatures and that the apparent change of onset temperature in the specific heat curves originates from the mechanism of transformation and the normalization procedure. An ad hoc surface normalization of the heat capacity yields curves which collapse into a single one irrespective of their thickness. Furthermore, we fit the surface-normalized specific heat curves with a heterogeneous transformation model to evaluate the velocity of the growth front over a much wider temperature interval than previously reported. Our data expands previous values up to Tg + 75 K, covering 12 orders of magnitude in relaxation times. The results are consistent with preceding experimental and theoretical studies. Interestingly, the mobility of the supercooled liquid in the region behind the transformation front remains constant throughout the thickness of the layers.

Electromagnetic fields at 2.45†GHz trigger changes in heat shock proteins 90 and 70 without altering apoptotic activity in rat thyroid gland.

Non-ionizing radiation at 2.45 GHz may modify the expression of genes that codify heat shock proteins (HSP) in the thyroid gland. Using the enzyme-linked immunosorbent assay (ELISA) technique, we studied levels of HSP-90 and HSP-70. We also used hematoxilin eosin to look for evidence of lesions in the gland and applied the DAPI technique of fluorescence to search for evidence of chromatin condensation and nuclear fragmentation in the thyroid cells of adult female Sprague-Dawley rats. Fifty-four rats were individually exposed for 30 min to 2.45 GHz radiation in a Gigahertz transverse electromagnetic (GTEM) cell at different levels of non-thermal specific absorption rate (SAR), which was calculated using the finite difference time domain (FDTD) technique. Ninety minutes after radiation, HSP-90 and HSP-70 had decreased significantly (P<0.01) after applying a SAR of 0.046±1.10 W/Kg or 0.104±5.10(-3) W/Kg. Twenty-four hours after radiation, HSP-90 had partially recovered and HSP-70 had recovered completely. There were few indications of lesions in the glandular structure and signs of apoptosis were negative in all radiated animals. The results suggest that acute sub-thermal radiation at 2.45 GHz may alter levels of cellular stress in rat thyroid gland without initially altering their anti-apoptotic capacity.

Stability of thin film glasses of toluene and ethylbenzene formed by vapor deposition: an in situ nanocalorimetric study.

Vapor deposited thin films (~100 nm thickness) of toluene and ethylbenzene grown by physical vapor deposition show enhanced stability with respect to samples slowly cooled from the liquid at a rate of 5 K min(-1). The heat capacity is measured in situ immediately after growth from the vapor or after re-freezing from the supercooled liquid at various heating rates using quasi-adiabatic nanocalorimetry. Glasses obtained from the vapor have low enthalpies and large heat capacity overshoots that are shifted to high temperatures. The stability is maximized at growth temperatures in the vicinity of 0.8 T(g) for both molecules, although glasses of ethylbenzene show superior stabilization. Our data is consistent with previous results of larger organic molecules suggesting a generalized behavior on the stability of organic glasses grown from the vapor. In addition, we find that for the small molecules analyzed here, slowing the growth rate below 0.1 nm s(-1) does not result in increased thermodynamic stability.

[Rosai-Dorfman's disease (sinus histiocytosis with massive lymphadenopathy): a report of a case and bibliographic review]. / Enfermedad de rosai-dorfman (histiocitosis sinusoidal con linfadenopatía masiva): comunicación de un caso y revisión de la bibliografía.

Rosai-Dorfman's illness, also denominated sinus histiocytosis with massive lymphadenopathy is considered benign entity of unknown etiology; although it is believed it may be due to alterations of immune system. It was described in 1969 by Rosai and Dorfman and there are nearly 500 cases worldwide reported. The most frequent clinical manifestation is massive lymph node enlargement, mainly cervical, but almost in the fifth percent of cases any lymph node may be affected. Diagnosis is pathological, without treatment of choice, evolution is often spontaneous resolution. In extraganglionar compromise, illness may be progressive and fatal. A45 year-old woman with cervical and nasal lymphadenopathy and fever is presented. Biopsy report: histiocytosis with emperipolesis phenomenon and immunohistochemical markers S-100, CD48, and CD45, positives. Encountering total T lymphopenia, mainly CD4+ diminished relationship CD4/CD8 and polyclonal gammopathy. Relevant in this case, clinical presentation multiple lymph nodes, distinct of other reported in our country whose presentation was mainly cutaneous plus association among Rosai-Dorfman with immunological changes and good clinical response to immunomodulator treatment, not previously seen, as in this patient.

Cephalometrics in children with Down's syndrome.

AIMS: To describe the craniofacial morphology of a group of patients with Down's syndrome using a cephalometric analysis of the lateral skull radiograph. MATERIALS AND METHODS: The studied sample consisted of 39 patients with Down's syndrome (24 boys, 15 girls) ranging from 7 to 18 years of age. The computerized cephalometric study of the lateral skull radiograph of each patient was carried out using the method described by Ricketts. RESULTS: Anterior cross-bite was observed in 38.4% of patients and diminished interincisal angle in 77%. Skeletal parameters matched the clinical norm, indicating mesofacial biotype, i.e., normal maxillomandibular growth. The lower incisors protruded in 84.6% of the individuals studied and were proinclined in 77%; upper incisors were protruded in 77% of the sample. The lower lip protruded in 84.6%. Analysis of craniofacial parameters showed average values within the clinical norm. Analysis of the inner cranium demonstrated normal inclination of the cranial base, while the length of the anterior skull base was diminished in 53.8%. CONCLUSIONS: From the skeletal perspective, patients with Down's syndrome who are in a period of growth demonstrate a reduction of the anterior skull base. From the dentoalveolar perspective, they show protrusion and proinclination of lower incisors, which is related to a tendency to anterior cross-bite and, to a lesser extent, to diminished overbite. Likewise, the lower lip protrusion observed in this study is related to the position of the lower incisor.

Nódulo y artritis erosiva: reporte de un caso / Nodules and erosive arthritis: a report of a case

Los síndromes histiocíticos son afecciones de difícil diagnóstico, que conciernen a los dermatólogos, a los médicos internistas, a los reumatólogos y a los patólogos. Las decisiones terapéuticas pueden ser de agresividad variable, produciendo una gran morbilidad. La reticulohistiocitosis multicéntrica es un padecimiento infrecuente cuya dificultad diagnóstica, así como los diagnósticos diferenciales, deben ser ampliamente conocidos.