Dose assesment with fast Monte Carlo codes in interventional radiology.

This study presents the performance of two fast Monte Carlo codes, PENELOPE/penEasyIR and MCGPU-IR in order to assess operator doses in interventional radiology. In particular, it aims to validate the calculations when workers are protected with shielding located between the patient and the operator. The experiments are performed in a calibration laboratory and measurements are gathered using Thermo EPD and Mirion DMC personal active dosemeters. Calculation efficiency of the fast Monte Carlo codes is approximately four orders of magnitude greater than for a standard Monte Carlo code. Satisfactory agreement between measurements and calculations is shown.

Analysis of marginal bone loss and implant stability quotient by resonance frequency analysis in different osteointegrated implant systems. Randomized prospective clinical trial.

BACKGROUND: The aim of the present prospective clinical study is to compare the stability of the implant-bone interface by the ISQ quotient and marginal bone loss (MBL) rate during one year of follow-up in four system implants with the same surface and different design. MATERIAL AND METHODS: Prospective randomized clinical trial of 21 patients in which four implant systems with the same surface and different design were placed. Patients were treated by the same operator following a similar surgical protocol with submerged technique. The second surgery to perform the prosthesis was performed at 3 months. All patients went to their review at 6 months and a year. A periapical radiograph for crestal bone analysis and an Implant stability quotient by resonance frequency analysis (ISQ) analysis were taken at baseline and the reviews. RESULTS: No statistically significant differences were found in the Implant stability quotient by resonance frequency analysis and Marginal Bone Loss in the four types of implants. The ISQ increased from the moment of insertion of the implant until the revision to the year, showing an increase of the stability implant, being this increasing less between the 6 months and the year. CONCLUSIONS: Differences in the design of the four implants tested in this study did not show statistically significant differences in any of the variables studied, so the implant design does not influence implant stability and marginal bone loss in the first year after placement.

Botulinum toxin A for patients with orofacial dystonia: prospective, observational, single-centre study.

The objective of this study was to demonstrate the efficacy of intramuscular botulinum toxin type A (BTX-A) as a method of controlling the symptoms of focal facial dystonia. A prospective, longitudinal, observational, pre-post (case-series) single-centre study was conducted over a period of 3 months, involving 30 patients with focal dystonia. The patients were enrolled on a first-come, first-served basis. For all patients, the abnormal movements were evaluated using the Abnormal Involuntary Movement Scale (AIMS). The AIMS results were recorded immediately before BTX-A injection (primary predictor variable) and after 3 months (the toxin reaches its maximum effect 2 weeks after injection, and the effect is maintained for 3 months). An improvement in AIMS score was the primary outcome variable. Treatment efficacy was evaluated using the Pearson correlation index with a level of significance of P<0.05. The average age of the study subjects was 70.9±12.7years (20 female, 10 male). The mean dose of BTX-A used was 27.4±20.5U. The mean improvement in AIMS score after treatment was 5.2±4.2. A significant correlation was found between the dose applied and the reduction in AIMS score (P<0.05). BTX-A can be used in the treatment of focal dystonia and provides reproducible results.

A Prospective, Double-Blind, Randomized, Controlled Clinical Trial in the Gingivitis Prevention with an Oligomeric Proanthocyanidin Nutritional Supplement.

AIM: To evaluate the effectiveness on tissue response of the new nutritional supplement made of oligomeric proanthocyanidins in induced gingivitis after 21 days of use. MATERIAL AND METHODS: A prospective, double-blind, randomized, controlled clinical trial was carried out on 20 patients; it is divided into an experimental group and a control group after fulfilling the selection criteria. Patients had to come 4 times during the study to register the Silness and Löe index, the gingival bleeding index, the plaque index, the inflammatory crevicular fluid study (IL6), and the changes in the brightness of the gingiva. No complementary hygiene methods were allowed during the 21 days. RESULTS: The Silness and Löe index was higher in the control group than in the experimental group, reaching a twofold difference between the groups (p < 0.0001). The gingival bleeding index also supports this fact, since the bleeding was lower in the experimental group (p < 0.005). However, the dental plaque on the tooth surface according to the plaque index was 33% higher in the experimental group (p < 0.006). Some differences in the IL-6 were found in the crevicular fluid (p < 0.0001). CONCLUSION: Oligomeric proanthocyanidins have an effect on the periodontal tissue's health. No effects on the accumulation of plaque on the tooth surface were found, so further studies are needed to determine the nature of the plaque.

Occupational dose reduction in cardiac catheterisation laboratory: a randomised trial using a shield drape placed on the patient.

The aim of this study was to evaluate the occupational radiation dose in interventional cardiology by using a shielding drape on the patient. A random study with and without the protective material was conducted. The following control parameters were registered: demographic data, number of stents, contrast media volume, fluoroscopy time, number of cine images, kerma-area product and cumulative air kerma. Occupational dose data were obtained by electronic active dosemeters. No statistically significant differences in the analysed control parameters were registered. The median dose value received by the interventional cardiologist was 50% lower in the group with a shielding drape with a statistically significant p-value <0.001. In addition, the median value of the maximum scatter radiation dose was 31% lower in this group with a statistically significant p-value <0.001. This study showed that a shielding drape is a useful tool for reducing the occupational radiation dose in a cardiac catheterisation laboratory.

Occupational eye lens doses in interventional cardiology. A multicentric study.

New European regulation regarding radiological protection of workers and more specifically the new occupational dose limit for the eye lens recently reduced to 20 mSv yr(-1) may affect interventional cardiologists. This paper presents a set of measurements of occupational doses performed in five interventional cardiology centres and then compared with the new dose limit. The measurement of occupational doses was performed over the apron at chest level using electronic dosemeters recording H p(10). In one of the centres, scatter dose at goggles was also measured with optically stimulated luminescence dosemeters calibrated in terms of H p(0.07). An average H p(10) over the apron of 46 µSv/procedure was measured for cardiologists. Lower doses were noted in other professionals like second cardiologists, nurses or anaesthetists. Procedures for valvular and other structural heart diseases involved the highest occupational doses, averaging over 100 µSv/procedure. Important differences in occupational doses among centres may be indicative of different radiation protection habits. The new occupational dose limit for the eye lens is likely to be exceeded by those among the interventionalists who do not use protection tools (ceiling suspended screen and/or goggles) even with standard workloads.

Radiation Doses in Patient Eye Lenses during Interventional Neuroradiology Procedures.

BACKGROUND AND PURPOSE: Eye lenses are among the most sensitive organs to x-ray radiation and may be considered at risk during neurointerventional radiology procedures. The threshold dose to produce eye lens opacities has been recently reduced to 500 mGy by the International Commission on Radiologic Protection. In this article, the authors investigated the radiation doses delivered to patients' eyes during interventional neuroradiology procedures at a university hospital. MATERIALS AND METHODS: Small optically stimulated luminescence dosimeters were located over patients' eyes during 5 diagnostic and 31 therapeutic procedures performed in a biplane x-ray system. Phantom measurements were also made to determine the level of radiation to the eye during imaging runs with conebeam CT. RESULTS: The left eye (located toward the lateral C-arm x-ray source) received a 4.5 times greater dose than the right one. The average dose during embolization in the left eye was 300 mGy, with a maximum of 2000 mGy in a single procedure. The patient who received this maximum eye dose needed 6 embolization procedures to treat his high-volume AVM. If one took into account those 6 embolizations, the eye dose could be 2-fold. Sixteen percent of the embolizations resulted in eye doses of >500 mGy. CONCLUSIONS: A relevant fraction of patients received eye doses exceeding the threshold of 500 mGy. A careful optimization of the procedures and follow-up of these patients to evaluate potential lens opacities should be considered.

Staff lens doses in interventional urology. A comparison with interventional radiology, cardiology and vascular surgery values.

The purpose of this work is to evaluate radiation doses to the lens of urologists during interventional procedures and to compare them with values measured during interventional radiology, cardiology and vascular surgery. The measurements were carried out in a surgical theatre using a mobile C-arm system and electronic occupational dosimeters (worn over the lead apron). Patient and staff dose measurements were collected in a sample of 34 urology interventions (nephrolithotomies). The same dosimetry system was used in other medical specialties for comparison purposes. Median and 3rd quartile values for urology procedures were: patient doses 30 and 40 Gy cm(2); personal dose equivalent Hp(10) over the apron (µSv/procedure): 393 and 848 (for urologists); 21 and 39 (for nurses). Median values of over apron dose per procedure for urologists resulted 18.7 times higher than those measured for radiologists and cardiologists working with proper protection (using ceiling suspended screens) in catheterisation laboratories, and 4.2 times higher than the values measured for vascular surgeons at the same hospital. Comparison with passive dosimeters worn near the eyes suggests that dosimeters worn over the apron could be a reasonable conservative estimate for ocular doses for interventional urology. Authors recommend that at least the main surgeon uses protective eyewear during interventional urology procedures.

Estimation of staff lens doses during interventional procedures. Comparing cardiology, neuroradiology and interventional radiology.

The purpose of this article is to estimate lens doses using over apron active personal dosemeters in interventional catheterisation laboratories (cardiology IC, neuroradiology IN and radiology IR) and to investigate correlations between occupational lens doses and patient doses. Active electronic personal dosemeters placed over the lead apron were used on a sample of 204 IC procedures, 274 IN and 220 IR (all performed at the same university hospital). Patient dose values (kerma area product) were also recorded to evaluate correlations with occupational doses. Operators used the ceiling-suspended screen in most cases. The median and third quartile values of equivalent dose Hp(10) per procedure measured over the apron for IC, IN and IR resulted, respectively, in 21/67, 19/44 and 24/54 µSv. Patient dose values (median/third quartile) were 75/128, 83/176 and 61/159 Gy cm(2), respectively. The median ratios for dosemeters worn over the apron by operators (protected by the ceiling-suspended screen) and patient doses were 0.36; 0.21 and 0.46 µSv Gy(-1) cm(-2), respectively. With the conservative approach used (lens doses estimated from the over apron chest dosemeter) we came to the conclusion that more than 800 procedures y(-1) and per operator were necessary to reach the new lens dose limit for the three interventional specialties.

A set of patient and staff dose data for validation of Monte Carlo calculations in interventional cardiology.

The purpose of this paper is to report a set of experimental values of patient and staff doses in a cardiac catheterisation laboratory using the range of radiographic and geometric parameters from routine clinical practice. The data obtained will be available for validation of Monte Carlo calculations and for training purposes. They will also help optimise radiation protection for patients and staff. Experimental measurements were made with an anthropomorphic phantom, and a monoplane flat detector-based X-ray system was used for interventional cardiology procedures. Standard operational protocols used in clinical practice were applied. Around 1000 patient dose and 5000 staff dose values were measured for different operational conditions (angulations, distances, collimation and wedge filter, magnification, phantom thicknesses, using Copper absorber, etc.). Uncertainties were also estimated. Increase factors of 3-10 for patients and staff doses were measured for the different C-arm angulations.

Benefits of an automatic patient dose registry system for interventional radiology and cardiology at five hospitals of the Madrid area.

The purpose of this article is to present the results of connecting the interventional radiology and cardiology laboratories of five university hospitals to a unique server using an automatic patient dose registry system (Dose On Line for Interventional Radiology, DOLIR) developed in-house, and to evaluate its feasibility more than a year after its introduction. The system receives and stores demographic and dosimetric parameters included in the MPPS DICOM objects sent by the modalities to a database. A web service provides a graphical interface to analyse the information received. During 2013, the system processed 10 788 procedures (6874 cardiac, 2906 vascular and 1008 neuro interventional). The percentages of patients requiring clinical follow-up due to potential tissue reactions before and after the use of DOLIR are presented. The system allowed users to verify in real-time, if diagnostic (or interventional) reference levels are fulfilled.

Práctica de la nutrición enteral en pediatría / Enteral nutrition support in pediatrics

Introducción: La nutrición enteral es la forma de soporte nutricional más utilizada. Su empleo en el paciente ingresado y en el domicilio ha aumentado en los últimos años. Sin embargo, pese a tratarse de la misma técnica de soporte nutricional, se trata de dos escenarios completamente distintos. El objetivo del presente estudio consiste en describir sus características y diferencias, así como su influencia en el estado nutricional. Pacientes y métodos: Se analizaron retrospectivamente las historias de 124 pacientes con nutrición enteral domiciliaria entre 1995 y 2013, y prospectivamente las de 50 pacientes con nutrición enteral hospitalaria. Se utilizó una estadística descriptiva para el estudio de las dos poblaciones y un análisis de inferencias para la comparación entre ambas (t de Student o ji al cuadrado, en función de las variables) y comparación de medidas repetidas para el estudio de la situación nutricional a lo largo del tiempo, mediante el programa estadístico SPSS 15.0. Se consideró significación estadística a partir de valores de p <0,05. Resultados: En la población domiciliaria, la media de edad de inicio era de 2,48 años. Las enfermedades principales fueron enfermedades del aparato digestivo o enfermedades neurológicas. La duración media fue de 33,29 meses, mientras que el tipo de acceso y el producto más usados fueron la sonda nasogástrica y la fórmula polimérica, respectivamente. Se observó mejoría del estado nutricional en esta población, al menos en cuanto al peso. En la población hospitalaria la media de edad de inicio fue de 1,29 años. La patología principal fue la respiratoria. La duración media fue de 1,12 meses, la mayoría de pacientes emplearon una sonda nasogástrica y los productos más usados fueron la leche materna y la fórmula polimérica pediátrica. No se apreció mejoría de la situación nutricional en esta población. Conclusiones: 1) A pesar de utilizar los mismos accesos enterales y productos, las características de los pacientes, la edad de inicio y los resultados desde el punto de vista nutricional fueron diferentes en las dos poblaciones comparadas. 2) La nutrición enteral domiciliaria contribuyó a la mejoría del estado nutricional, mientras que la hospitalaria no lo consiguió (AU)

Introduction: Enteral nutrition is the most used form of nutritional support. In the last years there has been an increased use of enteral nutrition both in the inpatients as well as in the outpatient scenario. Nevertheless they are quite different clinical conditions, despite the fact of using the same technique and products. The aim of the study was to describe the characteristics, the differences and the influence in the nutritional status. Subjects and methods: 124 pediatric patients with home enteral nutrition from 1995 to 2013 were analyzed retrospectively and 50 patients with enteral nutrition while in hospital in a 4-month-period were analyzed prospectively. Descriptive statistics for the study of the two populations and inference analysis for comparison between the two (Student-t test or x2, depending on variables) and a comparison of repeated measures for the study of the nutritional status along time was used, through the SPSS 15.0 statistical program. Statistical significance was based on p-values <0.05. Results: In the home enteral nutrition population the mean age at the start of treatment was 2.48 years. The main diseases were the gastrointestinal and neurological diseases. The average duration was 33.29 months, while the type of access and the most used product were e nasogastric tube and a polymeric formula respectively. An improvement of the nutritional status was observed, at least in weight. In the hospitalized patients the mean age at the start was 1.29 years, the main indication was a respiratory disease. The average duration was 1.12 months; most patients used a nasogastric tube and the most used products were breastmilk and a polymeric formula. An improvement of the nutritional status was not obtained in this population. Conclusions: 1) In spite of using the same type of enteral access and products, patients' characteristics, mean age at start and outcomes from a nutritional status point of view, were very different between both populations. 2) Home enteral nutrition contributed to the improvement of the nutritional status, whereas the enteral nutrition in hospital did not (AU)

Brain radiation doses to patients in an interventional neuroradiology laboratory.

BACKGROUND AND PURPOSE: In 2011, the International Commission on Radiologic Protection established an absorbed-dose threshold to the brain of 0.5 Gy as likely to produce cerebrovascular disease. In this paper, the authors investigated the brain doses delivered to patients during clinical neuroradiology procedures in a university hospital. MATERIALS AND METHODS: The radiation dose delivered to the brain was investigated in 99 diagnostic and therapeutic interventional neuroradiology procedures. Brain doses were calculated in a mathematic model of an adult standard anthropomorphic phantom by using the technical and radiation dose data of an x-ray biplane system submitted to regular quality controls and calibration programs. RESULTS: For cerebral embolizations, brain doses resulted in a maximum value of 1.7 Gy, with an average value of 500 mGy. Median and third quartile resulted in 400 and 856 mGy, respectively. For cerebral angiography, the average dose in the brain was 100 mGy. CONCLUSIONS: This work supports the International Commission on Radiologic Protection recommendation on enhancing optimization when doses to the brain could be higher than 0.5 Gy. Radiation doses should be recorded for all patients and kept as low as reasonably achievable. For pediatric patients and young adults, an individual evaluation of brain doses could be appropriate.

Measurements of eye lens doses in interventional cardiology using OSL and electronic dosemeters†.

The purpose of this paper is to test the appropriateness of OSL and electronic dosemeters to estimate eye lens doses at interventional cardiology environment. Using TLD as reference detectors, personal dose equivalent was measured in phantoms and during clinical procedures. For phantom measurements, OSL dose values resulted in an average difference of -15 % vs. TLD. Tests carried out with other electronic dosemeters revealed differences up to ±20 % versus TLD. With dosemeters positioned outside the goggles and when TLD doses were >20 µSv, the average difference OSL vs. TLD was -9 %. Eye lens doses of almost 700 µSv per procedure were measured in two cases out of a sample of 33 measurements in individual clinical procedures, thus showing the risk of high exposure to the lenses of the eye when protection rules are not followed. The differences found between OSL and TLD are acceptable for the purpose and range of doses measured in the survey.

Spirotetramat induce cambios histológicos y bioquímicos en rata Wistar / Spirotetramat induces histological and biochemical changes in Wistar rats

Spirotetramat, comercialmente conocido como Movento®, es derivado del ácido tetrámico, empleado en el cultivo de la vid y de algunos vegetales para el control de parásitos chupadores. Los estudios toxicológicos in vivo solo publican una descripción general de su metabolismo. El objetivo de este estudio fue conocer los cambios en el comportamiento, en indicadores bioquímicos séricos e histológicos en ratas Wistar macho. Se realizó los siguientes tratamientos: a) intoxicación aguda con Spirotetramat (BY108330, 15.3%) vía oral con 1⁄4 DL50 (625 mg kg-1) y 1⁄2 DL50 (1250 mg kg-1), y b) control. Se obtuvieron muestras de sangre mediante punción cardíaca los días 1, 3 y 7; las muestras se evaluaron por cambios en indicadores bioquímicos (triglicéridos, colesterol, albúmina, proteína total, actividad de transaminasas, urea y creatinina), y cambios histológicos en hígado, riñón y páncreas. Se presentó la muerte en el 35% de los animales tratados. Se observaron signos de toxicidad como: salivación, ataxia, convulsiones, sangrado nasal y diarrea. El peso corporal y el peso relativo del hígado en promedio fueron constantes, sin diferencias entre tratamientos, ni entre días. El perfil lipídico y las transaminasas presentaron una tendencia al incremento en relación al control. En la evaluación histológica los hepatocitos mostraron degeneración balonoide en el 25% (8 de 32) y colestasis en el 72% (23 de 32) de las ratas intoxicadas, sin embargo en bazo y riñón no se observaron cambios visibles en relación al control (AU)

Spirotetramat, derived from tetramic acid, and commercially known as Movento®, is applied in grapevine orchards and other vegetable for the control of sucking pests. Published in vivo toxicological studies report only a general description of its metabolism. The objective of this study was to detect changes in the behavior, in blood biochemical markers, and in histological liver cells on male Wistar rats treated with spirotetramat. The following treatments were applied: a) acute poisoning with spirotetramat (BY108330, 15.3%) oral route with 1⁄4 DL50 (625 mg kg- 1) and 1⁄2 DL50 (1250 mg kg-1), and b) control. Blood samples were obtained by heart punction on days 1, 3 and 7; the samples were evaluated for changes of biochemical indicators (triglycerides, cholesterol, albumin, total protein, transaminase activity, urea and creatinine), and by histological changes in liver, kidney and pancreas. Death occurred in 35% of the treated animals. Some signs of toxicity were observed: nasal running, diarrhea, salivation, ataxia, convulsions, and bleeding. The average body weight and the liver relative weight were stable during the experiment, without differences between treatments, nor between days. The lipid profile and transaminases showed a clear tendency to increase in relation to the control. In the histological evaluation the hepatocytes showed balloonoide degeneration in 25% (8 of 32) and cholestasis in 72% (23 of 32) of the exposed rats; however, there were not visible changes in spleen and kidney in relation to the control (AU)

Patient radiation dose management in the follow-up of potential skin injuries in neuroradiology.

BACKGROUND AND PURPOSE: Radiation exposure from neurointerventional procedures can be substantial, with risk of radiation injuries. We present the results of a follow-up program applied to potential skin injuries in interventional neuroradiology based on North American and European guidelines. MATERIALS AND METHODS: The following guidelines approved in 2009 by SIR and CIRSE have been used over the last 2 years to identify patients with potential skin injuries requiring clinical follow-up: peak skin dose >3 Gy, air kerma at the patient entrance reference point >5 Gy, kerma area product >500 Gy · cm(2), or fluoroscopy time >60 minutes. RESULTS: A total of 708 procedures (325 in 2009 and 383 in 2010) were included in the study. After analyzing each dose report, 19 patients (5.9%) were included in a follow-up program for potential skin injuries in 2009, while in 2010, after introducing several optimizing actions and refining the selection criteria, only 4 patients (1.0%) needed follow-up. Over the last 2 years, only 3 patients required referral to a dermatology service. CONCLUSIONS: The application of the guidelines to patient radiation dose management helped standardize the selection criteria for including patients in the clinical follow-up program of potential skin radiation injuries. The peak skin dose resulted in the most relevant parameter. The refinement of selection criteria and the introduction of a low-dose protocol in the x-ray system, combined with a training program focused on radiation protection, reduced the number of patients requiring clinical follow-up.

A new species of Acanthostigma (Tubeufiaceae, Dothideomycetes) from the southern hemisphere.

A new species belonging to the Dothideomycete genus Acanthostigma is described from bark of two Nothofagus species from Argentina. Its identity as a new species is based on both morphology and molecular sequence data. Acanthostigma patagonica differs from other species in the genus by having larger ascomata and setae and wider, asymmetrical ascospores. An amended key to Acanthostigma species is provided along with a discussion of other species previously described from South America.

Quality index, consumer acceptability, bioactive compounds, and antioxidant activity of fresh-cut "ataulfo" mangoes (mangifera indica L.) as affected by low-temperature storage.

To measure bioactive compound losses due to minimal processing, mature green fresh-cut mangoes (Mangifera indica L.) cv. "Ataulfo" were subjected to an antioxidant treatment and stored at 5 degrees C during 15 d. Quality index, total phenols, flavonoids, beta-carotene, ascorbic acid, vitamin E, and antioxidant activity were measured during the storage period of fruits. Antioxidant capacity was estimated using ORAC(FL), TEAC, and DPPH assays. The dipping treatments with ascorbic acid (AA) + citric acid (CA) + CaCl2 affected positively quality delaying deterioration of fresh-cut mango as compared with whole fruit. However, dipping treatment affected the consumer preferences of fresh-cut mangoes. The highest vitamin C, beta-carotene, and vitamin E losses were observed after 10 d, being similar in whole and fresh-cut mangoes. The antioxidant activity was not significantly affected by storage time. We conclude that fresh-cut mangoes retained their bioactive compound content during storage and their antioxidant and nutritional properties make them a good source of these compounds.

Involvement of the Rho/Rac family member RhoG in caveolar endocytosis.

We show here that the GTPase RhoG is involved in caveolar trafficking. Wild-type RhoG moves sequentially to the plasma membrane, intracellular vesicles, and the Golgi apparatus along markers of this endocytic pathway. Such translocation is associated with changes in RhoG GDP/GTP levels and is highly dependent on lipid raft integrity and on the function of the GTPase dynamin2. In addition, the constitutively active RhoG(Q61L) mutant is preferentially located in endocytic vesicles that can be decorated with markers of the caveola-derived endocytic pathway. RhoG(Q61L), but not the analogous Rac1 mutant protein, affects caveola internalization and the subsequent delivery of endocytic vesicles to the Golgi apparatus. The expression of RhoG/Rac1 chimeric proteins and RhoG(Q61L) effector mutants in cells induces alterations in the internalization of caveolae and severe changes in vesicle structure, respectively. However, the knockdown of endogenous rhoG transcripts using small interfering RNAs does not affect significantly the trafficking of caveola-derived vesicles, suggesting that RhoG function is dispensable for this endocytic process or, alternatively, that its function is compensated by other molecules. Taken together, these observations assign a novel function to RhoG and suggest that caveolar trafficking, as previously shown for other endocytic routes, is modulated by GTPases of the Ras superfamily.

Sexual dimorphism in lipid metabolic phenotype associated with old age in Sprague-Dawley rats.

PURPOSE: Aged male rats show a decrease in liver PPARalpha. We aimed to determine if the sexual dimorphism in lipid metabolism observed in the PPARalpha-/- mouse is also present in senescent rats. RESULTS: Eighteen-month old rats were obese and presented high plasma NEFA concentrations. Old male rats were more hypercholesterolemic and hyperleptinemic than females, presenting a higher content in hepatic triglycerides and cholesteryl esters, while 18-month old females were more hypertriglyceridemic than males. Although PPARalpha expression and binding activity was reduced in liver from old male and female rats, the mRNA for a PPARalpha target gene, such as CPT-I, was reduced in old males (-56%), while increased by 286% in old females. LXRalpha protein was increased, and its binding activity was decreased in livers of old males, while livers of old females showed an increase in DGAT1 (2.6-fold) and DGAT2 (4.9-fold) mRNA, with respect to 3-month old animals. The increases in DGAT1 and DGAT2 mRNAs matched in old females those of plasma (3.1-fold) and liver triglycerides (5.0-fold). CONCLUSIONS: These features disclose a marked sexual dimorphism in lipid metabolism associated to old age in rats that can be partially attributed not only to an age-related decrease in liver PPARalpha expression, but also to changes in other hepatic transcription factors and enzymes, such as liver X receptor alpha (LXRalpha) and diacylglycerol acyltransferases (DGAT).