A 2D ferroelectric vortex pattern in twisted BaTiO3 freestanding layers.

The wealth of complex polar topologies1-10 recently found in nanoscale ferroelectrics results from a delicate balance between the intrinsic tendency of the materials to develop a homogeneous polarization and the electric and mechanical boundary conditions imposed on them. Ferroelectric-dielectric interfaces are model systems in which polarization curling originates from open circuit-like electric boundary conditions, to avoid the build-up of polarization charges through the formation of flux-closure11-14 domains that evolve into vortex-like structures at the nanoscale15-17 level. Although ferroelectricity is known to couple strongly with strain (both homogeneous18 and inhomogeneous19,20), the effect of mechanical constraints21 on thin-film nanoscale ferroelectrics has been comparatively less explored because of the relative paucity of strain patterns that can be implemented experimentally. Here we show that the stacking of freestanding ferroelectric perovskite layers with controlled twist angles provides an opportunity to tailor these topological nanostructures in a way determined by the lateral strain modulation associated with the twisting. Furthermore, we find that a peculiar pattern of polarization vortices and antivortices emerges from the flexoelectric coupling of polarization to strain gradients. This finding provides opportunities to create two-dimensional high-density vortex crystals that would enable us to explore previously unknown physical effects and functionalities.

Observation of room-temperature polar skyrmions.

Complex topological configurations are fertile ground for exploring emergent phenomena and exotic phases in condensed-matter physics. For example, the recent discovery of polarization vortices and their associated complex-phase coexistence and response under applied electric fields in superlattices of (PbTiO3)n/(SrTiO3)n suggests the presence of a complex, multi-dimensional system capable of interesting physical responses, such as chirality, negative capacitance and large piezo-electric responses1-3. Here, by varying epitaxial constraints, we discover room-temperature polar-skyrmion bubbles in a lead titanate layer confined by strontium titanate layers, which are imaged by atomic-resolution scanning transmission electron microscopy. Phase-field modelling and second-principles calculations reveal that the polar-skyrmion bubbles have a skyrmion number of +1, and resonant soft-X-ray diffraction experiments show circular dichroism, confirming chirality. Such nanometre-scale polar-skyrmion bubbles are the electric analogues of magnetic skyrmions, and could contribute to the advancement of ferroelectrics towards functionalities incorporating emergent chirality and electrically controllable negative capacitance.

Local negative permittivity and topological phase transition in polar skyrmions.

Topological solitons such as magnetic skyrmions have drawn attention as stable quasi-particle-like objects. The recent discovery of polar vortices and skyrmions in ferroelectric oxide superlattices has opened up new vistas to explore topology, emergent phenomena and approaches for manipulating such features with electric fields. Using macroscopic dielectric measurements, coupled with direct scanning convergent beam electron diffraction imaging on the atomic scale, theoretical phase-field simulations and second-principles calculations, we demonstrate that polar skyrmions in (PbTiO3)n/(SrTiO3)n superlattices are distinguished by a sheath of negative permittivity at the periphery of each skyrmion. This enhances the effective dielectric permittivity compared with the individual SrTiO3 and PbTiO3 layers. Moreover, the response of these topologically protected structures to electric field and temperature shows a reversible phase transition from the skyrmion state to a trivial uniform ferroelectric state, accompanied by large tunability of the dielectric permittivity. Pulsed switching measurements show a time-dependent evolution and recovery of the skyrmion state (and macroscopic dielectric response). The interrelationship between topological and dielectric properties presents an opportunity to simultaneously manipulate both by a single, and easily controlled, stimulus, the applied electric field.

Artificial chemical and magnetic structure at the domain walls of an epitaxial oxide.

Progress in nanotechnology requires new approaches to materials synthesis that make it possible to control material functionality down to the smallest scales. An objective of materials research is to achieve enhanced control over the physical properties of materials such as ferromagnets, ferroelectrics and superconductors. In this context, complex oxides and inorganic perovskites are attractive because slight adjustments of their atomic structures can produce large physical responses and result in multiple functionalities. In addition, these materials often contain ferroelastic domains. The intrinsic symmetry breaking that takes place at the domain walls can induce properties absent from the domains themselves, such as magnetic or ferroelectric order and other functionalities, as well as coupling between them. Moreover, large domain wall densities create intense strain gradients, which can also affect the material's properties. Here we show that, owing to large local stresses, domain walls can promote the formation of unusual phases. In this sense, the domain walls can function as nanoscale chemical reactors. We synthesize a two-dimensional ferromagnetic phase at the domain walls of the orthorhombic perovskite terbium manganite (TbMnO3), which was grown in thin layers under epitaxial strain on strontium titanate (SrTiO3) substrates. This phase is yet to be created by standard chemical routes. The density of the two-dimensional sheets can be tuned by changing the film thickness or the substrate lattice parameter (that is, the epitaxial strain), and the distance between sheets can be made as small as 5 nanometres in ultrathin films, such that the new phase at domain walls represents up to 25 per cent of the film volume. The general concept of using domain walls of epitaxial oxides to promote the formation of unusual phases may be applicable to other materials systems, thus giving access to new classes of nanoscale materials for applications in nanoelectronics and spintronics.

Deterministic switching of ferromagnetism at room temperature using an electric field.

The technological appeal of multiferroics is the ability to control magnetism with electric field. For devices to be useful, such control must be achieved at room temperature. The only single-phase multiferroic material exhibiting unambiguous magnetoelectric coupling at room temperature is BiFeO3 (refs 4 and 5). Its weak ferromagnetism arises from the canting of the antiferromagnetically aligned spins by the Dzyaloshinskii-Moriya (DM) interaction. Prior theory considered the symmetry of the thermodynamic ground state and concluded that direct 180-degree switching of the DM vector by the ferroelectric polarization was forbidden. Instead, we examined the kinetics of the switching process, something not considered previously in theoretical work. Here we show a deterministic reversal of the DM vector and canted moment using an electric field at room temperature. First-principles calculations reveal that the switching kinetics favours a two-step switching process. In each step the DM vector and polarization are coupled and 180-degree deterministic switching of magnetization hence becomes possible, in agreement with experimental observation. We exploit this switching to demonstrate energy-efficient control of a spin-valve device at room temperature. The energy per unit area required is approximately an order of magnitude less than that needed for spin-transfer torque switching. Given that the DM interaction is fundamental to single-phase multiferroics and magnetoelectrics, our results suggest ways to engineer magnetoelectric switching and tailor technologically pertinent functionality for nanometre-scale, low-energy-consumption, non-volatile magnetoelectronics.

Rare-earth nickelates RNiO3: thin films and heterostructures.

This review stands in the larger framework of functional materials by focussing on heterostructures of rare-earth nickelates, described by the chemical formula RNiO3 where R is a trivalent rare-earth R = La, Pr, Nd, Sm, …, Lu. Nickelates are characterized by a rich phase diagram of structural and physical properties and serve as a benchmark for the physics of phase transitions in correlated oxides where electron-lattice coupling plays a key role. Much of the recent interest in nickelates concerns heterostructures, that is single layers of thin film, multilayers or superlattices, with the general objective of modulating their physical properties through strain control, confinement or interface effects. We will discuss the extensive studies on nickelate heterostructures as well as outline different approaches to tuning and controlling their physical properties and, finally, review application concepts for future devices.

Phase coexistence and electric-field control of toroidal order in oxide superlattices.

Systems that exhibit phase competition, order parameter coexistence, and emergent order parameter topologies constitute a major part of modern condensed-matter physics. Here, by applying a range of characterization techniques, and simulations, we observe that in PbTiO3/SrTiO3 superlattices all of these effects can be found. By exploring superlattice period-, temperature- and field-dependent evolution of these structures, we observe several new features. First, it is possible to engineer phase coexistence mediated by a first-order phase transition between an emergent, low-temperature vortex phase with electric toroidal order and a high-temperature ferroelectric a1/a2 phase. At room temperature, the coexisting vortex and ferroelectric phases form a mesoscale, fibre-textured hierarchical superstructure. The vortex phase possesses an axial polarization, set by the net polarization of the surrounding ferroelectric domains, such that it possesses a multi-order-parameter state and belongs to a class of gyrotropic electrotoroidal compounds. Finally, application of electric fields to this mixed-phase system permits interconversion between the vortex and the ferroelectric phases concomitant with order-of-magnitude changes in piezoelectric and nonlinear optical responses. Our findings suggest new cross-coupled functionalities.

Phenotype in patients with intellectual disability and pathological results in array CGH. / Fenotipo en pacientes con discapacidad intelectual y array-CGH patológico.

INTRODUCTION: Global developmental delay (GDD) and intellectual disability (ID) are frequent reasons for consultation in paediatric neurology departments. Nowadays, array comparative genomic hybridisation (array-CGH) is one of the most widely used techniques for diagnosing these disorders. Our purpose was to determine the phenotypic features associated with pathological results in this genetic test. METHODS: We conducted a blind study of the epidemiological, clinical, anthropometric, and morphological features of 80 patients with unexplained ID to determine which features were associated with pathological results in array-CGH. RESULTS: Pathological results were found in 27.5% of the patients. Factors associated with pathological results in array-CGH were a family history of GDD/ID (OR = 12.1), congenital malformations (OR = 5.33), having more than 3 facial dysmorphic features (OR = 20.9), and hypotonia (OR = 3.25). CONCLUSIONS: Our findings are consistent with those reported by other published series. We therefore conclude that the probability of having pathological results in array-CGH increases with the presence of any of the features mentioned above in patients with ID/GDD.

[Peripartum cardiomyopathy with biventricular failure plus pulmonary thromboembolism and atrial septal defect]. / Miocardiopatía periparto con fallo biventricular más tromboembolismo pulmonar y comunicación interauricular.

This case report examines peripartum cardiomyopathy (PPCM), a rare variant of heart failure with reduced ejection fraction, which manifests at the end of labor or puerperium. The frequency of this pathology varies globally, and its association with risk factors such as genetic disorders, autoimmune diseases, viral infections, suggests a multifactorial etiology. Diagnostic criteria include: Heart failure secondary to left ventricular systolic dysfunction, manifested in the puerperium or at the end of pregnancy and lack of other identifiable causes of heart failure. The case presents a patient with no significant personal pathological history, who, 17 days post cesarean section developed acute symptoms, including abdominal pain, dry cough and dyspnea. Clinical findings revealed hypoxemia, alterations in blood tests and an echocardiogram that confirmed an atrial septal defect. Multidisciplinary management resulted in successful treatment and the patient was discharged without complications. This case highlights the importance of MCPP, a disease with high maternal mortality. The connection between atrial septal defect and PPCM, as well as the involvement of pulmonary thromboembolism.

[Atlantoid assimilation: malformation, compensation or deformity. Is it part of basilar invagination?] / Asimilación atlantoidea: malformación, compensación o deformidad. ¿Es parte de la invaginación basilar?

INTRODUCTION: atlas assimilation can occur alone or in association with other craniocervical junction malformations and deformities. The etiological and pathological mechanisms are not clear. CASE PRESENTATION: patient in her sixth decade of life, who was treated at the "Eugenio Espejo" Hospital, with asymmetric pyramidal symptoms after a low-energy kinetic fall. The condition completely reverted with conservative management. The patient is currently under periodic observation. CONCLUSION: the atlas assimilation, a congenital malformation, often asymptomatic; it is part of an embryological compensation when it is associated with other malformations. The appearance of deformity is necessary to reach atlantoaxial instability that it is not early. The knowledge of the concepts and distinction of the craniocervical junction abnormalities allows to indicate the best treatment in order to obtain the most suitable results with the individualization of each case.

INTRODUCCIÓN: la asimilación atlantoidea puede presentarse sola o asociada a otras malformaciones y deformidades de la unión craneocervical, los mecanismos etiológicos y patológicos no están esclarecidos. PRESENTACIÓN DE CASO: paciente de la sexta década de vida, quien fue atendida en el Hospital de Especialidades "Eugenio Espejo", con datos clínicos piramidales asimétricos, posteriores a mecanismo de lesión de caída con cinética de baja energía. La sintomatología revirtió con manejo conservador. En la actualidad, la paciente está bajo observación periódica. CONCLUSIÓN: la asimilación atlantoidea es una malformación congénita muchas veces asintomática y parte de una compensación embriológica cuando está asociada a otras malformaciones. Es necesaria la aparición de deformidad para llegar a la inestabilidad atlantoaxoidea que no es temprana. El conocimiento y poder diferenciar los conceptos de las anormalidades de la unión craneocervical permiten indicar el mejor tratamiento y así obtener los resultados más adecuados con la individualización de cada caso.

[Abusive head trauma. A review of our experience]. / Traumatismo craneal por maltrato. Revisión de nuestra experiencia.

INTRODUCTION: Abusive head trauma (AHT) is defined as an injury to the skull or intracranial contents due to inflicted blunt impact and/or shaking. It is characterized by the triad: encephalopathy, retinal haemorrhages and subdural hematoma. The main objective is to know the epidemiological, clinical and radiological characteristics; as well as the short and long term outcomes of patients diagnosed with AHT. PATIENTS AND METHODS: It is a descriptive, observational and retrospective study of the 19 patients diagnosed with AHT at a tertiary hospital from 1990 to 2018, both included. RESULTS: The mean age of the patients was 5,5 months with parity between both sexes. The principal medical histories reported were: absence of trauma (n = 9), history of a short fall (n = 6) and shaking (n = 4). The most frequent initial presentation was severe, and seizures was the main symptom (n = 8). Retinal haemorrhages were present in fifteen patients and subdural hematoma or hygroma in fifteen patients. Two patients died, seven presented short-term outcomes, and ten of the twelve patients who were performed a follow-up presented long-term outcomes. These outcomes were manifested as cognitive or behavioural disorders (n = 5) or as neurological disorders (n = 6). CONCLUSIONS: The epidemiological, clinical and radiological characteristics found are very similar to those reported in the literature. The prevalence of outcomes is high and they appear as cognitive or behavioural disorders.

TITLE: Traumatismo craneal por maltrato. Revisión de nuestra experiencia.Introducción. El traumatismo craneal por maltrato (TCM) se define como todo traumatismo que ocasiona lesiones intracraneales debido a un impacto directo infligido y/o zarandeo, y se caracteriza por la tríada de encefalopatía, hemorragias retinianas y hematoma subdural. El objetivo de este estudio es conocer las características epidemiológicas, clínicas y radiológicas, así como las secuelas de los pacientes diagnosticados de TCM. Pacientes y métodos. Estudio descriptivo observacional retrospectivo de los 19 pacientes diagnosticados de TCM en un hospital terciario entre 1990 y 2018, ambos inclusive. Resultados. La edad media de los afectados fue de 5,5 meses y existe paridad entre ambos sexos. Las anamnesis aportadas por los cuidadores fueron: ausencia de traumatismo (n = 9), antecedente de caída (n = 6) y zarandeo (n = 4). La clínica inicial más prevalente fueron los síntomas graves, y las convulsiones fueron el síntoma más frecuente (n = 8). Quince pacientes presentaron hemorragias retinianas y otros 15, hematoma subdural o higroma. Dos pacientes fallecieron, siete presentaron secuelas en el alta y 10 de los 12 pacientes en los que se realizó seguimiento presentaron secuelas tardías manifestadas como secuelas cognitivas/comportamiento (n = 5) o como secuelas neurológicas (n = 6). Conclusiones. Las características epidemiológicas, clínicas y radiológicas son muy similares a las publicadas en la bibliografía. La presencia de secuelas es prevalente y éstas se manifiestan tanto como problemas cognitivos y de comportamiento como por secuelas neurológicas.

Multiferroic phase transition near room temperature in BiFeO3 films.

In multiferroic BiFeO(3) thin films grown on highly mismatched LaAlO(3) substrates, we reveal the coexistence of two differently distorted polymorphs that leads to striking features in the temperature dependence of the structural and multiferroic properties. Notably, the highly distorted phase quasiconcomitantly presents an abrupt structural change, transforms from a standard to a nonconventional ferroelectric, and transitions from antiferromagnetic to paramagnetic at 360±20 K. These coupled ferroic transitions just above room temperature hold promises of giant piezoelectric, magnetoelectric, and piezomagnetic responses, with potential in many applications fields.

Point-of-care ultrasound after attempted suicidal hanging.

Focused cardiac ultrasound (FoCUS) can provide critical information quickly to determine the etiology after cardiac arrest and may expedite a diagnosis in order to identify underlying treatable causes. We present a case of reversible acute left ventricular dysfunction after cardiopulmonary resuscitation following attempted suicide by hanging presenting with severe hypoxemia. FoCUS revealed findings consistent with severe left ventricular dysfunction, and point-of-care ultrasound (PoCUS) ruled out pneumothorax. These findings, in conjunction with the clinical presentation, facilitated an early identification and rapid evaluation of cardiogenic shock; furthermore, they led to the use of FoCUS, which can provide critical information quickly on site for a patient who is suddenly symptomatic after severe mechanical asphyxia in the pediatric emergency department, pediatric intensive care unit, or the prehospital setting.

Optic neuritis in paediatric patients: Experience over 27 years and a management protocol. / Neuritis óptica en pediatría: experiencia en 27 años y protocolo de actuación.

INTRODUCTION AND OBJECTIVE: In this article, we present our experience on optic neuritis (ON) and provide a diagnostic/therapeutic protocol, intended to rule out other aetiologies (particularly infection), and a fact sheet for parents. MATERIAL AND METHODS: We conducted a descriptive, retrospective study of patients with ON over a 27-year period (1990-2017). A review of the available scientific evidence was performed in order to draft the protocol and fact sheet. RESULTS: Our neuropaediatrics department has assessed 20,744 patients in the last 27 years, of whom 14 were diagnosed with ON: 8 had isolated ON, 1 had multiple sclerosis (MS), 1 had clinically isolated syndrome (CIS), 3 had acute disseminated encephalomyelitis, and 1 had isolated ON and a history of acute disseminated encephalomyelitis one year previously. Patients' age range was 4-13 years; 50% were boys. Eight patients were aged over 10: 7 had isolated ON and 1 had MS. Nine patients had bilateral ON, and 3 had retrobulbar ON. MRI results were normal in 7 patients and showed involvement of the optic nerve only in 2 patients and optic nerve involvement + central nervous system demyelination in 5. Thirteen patients received corticosteroids. One patient had been vaccinated against meningococcus-C the previous month. Progression was favourable, except in the patient with MS. A management protocol and fact sheet are provided. CONCLUSIONS: ON usually has a favourable clinical course. In children aged older than 10 years with risk factors for MS or optic neuromyelitis (hyperintensity on brain MRI, oligoclonal bands, anti-NMO antibody positivity, ON recurrence), the initiation of immunomodulatory treatment should be agreed with the neurology department. The protocol is useful for diagnostic decision-making, follow-up, and treatment of this rare disease with potentially major repercussions. The use of protocols and fact sheets is important.

Adrenomedullin as a potential biomarker involved in patients with hereditary hemorrhagic telangiectasia.

BACKGROUND: Adrenomedullin (AM) is a vasoactive peptide mostly secreted by endothelial cells with an important role in preserving endothelial integrity.  The relationship between AM and hereditary hemorrhagic telangiectasia (HHT) is unknown. We aimed to compare the serum levels and tissue expression of AM between HHT patients and controls. METHODS: Serum AM levels were measured by radioimmunoassay and compared between control and HHT groups. AM levels were also compared among HHT subgroups according to clinical characteristics. The single nucleotide polymorphism (SNP) rs4910118 was assessed by restriction analysis and sequencing. AM immunohistochemistry was performed on biopsies of cutaneous telangiectasia from eight HHT patients and on the healthy skin from five patients in the control group. RESULTS: Forty-five HHT patients and 50 healthy controls were included, mean age (SD) was 50.7 (14.9) years and 46.4 (9.9) years (p = 0.102), respectively. HHT patients were mostly female (60% vs 38%, p = 0.032). Median [Q1-Q3] serum AM levels were 68.3 [58.1-80.6] pg/mL in the HHT group and 47.7 [43.2-53.8] pg/mL in controls (p<0.001), with an optimal AM cut-off according to Youden's J statistic of 55.32 pg/mL (J:0.729). Serum AM levels were similar in the HHT subgroups. No patient with HHT had the SNP rs4910118. AM immunoreactivity was found with high intensity in the abnormal blood vessels of HHT biopsies. CONCLUSIONS: We detected higher AM serum levels and tissue expression in patients with HHT than in healthy controls. The role of AM in HHT, and whether AM may constitute a novel biomarker and therapeutic target, needs further investigation.

Functional progression of patients with neurological diseases in a tertiary paediatric intensive care unit: Our experience. / Patología neurológica en una unidad de cuidados intensivos pediátricos de tercer nivel. Evolución funcional. Nuestra experiencia.

INTRODUCTION: Neurological diseases explain a considerable proportion of admissions to paediatric intensive care units (PICU), and are a significant cause of morbidity and mortality. This study aims to analyse the functional progression of children with critical neurological conditions. MATERIAL AND METHODS: Retrospective descriptive study of children admitted to PICU with neurological diseases over a period of 3 years (2012-2014), assessing vital and functional prognosis at PICU discharge and at one year according to the Pediatric Cerebral and Overall Performance Category scales (PCPC-POPC) and the Functional Status Scale (FSS). The results are compared with our previous data (1990-1999), and those of the international multicentre PANGEA study. RESULTS: A total of 266 children were studied. The mortality rate was 3%; the PRISM-III and PIM2 models did not show predictive ability. Clinically significant worsening was observed in functional health at discharge in 30% of the sample, according to POPC, 15% according to PCPC, and 5% according to FSS. After one year, functional performance improved according to PCPC-POPC, but not according to FSS. Children with no underlying neurological disease had a higher degree of functional impairment; this was prolonged over time. We observed a decrease in overall and neurocritical mortality compared with our previous data (5.60 vs. 2.1%, P=.0003, and 8.44 vs. 2.63%, P=.0014, respectively). Compared with the PANGEA study, both mortality and cerebral functional impairment in neurocritical children were lower in our study (1.05 vs. 13.32%, P<.0001, and 10.47% vs. 23.79%, P<.0001, respectively). CONCLUSIONS: Nearly one-third of critically ill children have neurological diseases. A significant percentage, mainly children without underlying neurological diseases, had a clinically significant functional impact at PICU discharge and after a year. Neuromonitoring and neuroprotection measures and the evaluation of functional progression are necessary to improve critical child care.

Functional assessment of a series of paediatric patients receiving neurointensive treatment: New Functional status scale. / Valoración funcional tras tratamiento neurointensivo pediátrico. Nueva escala de estado funcional (FSS).

INTRODUCTION: Functional health, a reliable parameter of the impact of disease, should be used systematically to assess prognosis in paediatric intensive care units (PICU). Developing scales for the assessment of functional health is therefore essential. The Paediatric Overall and Cerebral Performance Category (POPC, PCPC) scales have traditionally been used in paediatric studies. The new Functional Status Scale (FSS) was designed to provide more objective results. This study aims to confirm the validity of the FSS compared to the classic POPC and PCPC scales, and to evaluate whether it may also be superior to the latter in assessing of neurological function. PATIENTS AND METHOD: We conducted a retrospective descriptive study of 266 children with neurological diseases admitted to intensive care between 2012 and 2014. Functional health at discharge and at one year after discharge was evaluated using the PCPC and POPC scales and the new FSS. RESULTS: Global FSS scores were found to be well correlated with all POPC scores (P<.001), except in category 5 (coma/vegetative state). Global FSS score dispersion increases with POPC category. The neurological versions of both scales show a similar correlation. DISCUSSION: Comparison with classic POPC and PCPC categories suggests that the new FSS scale is a useful method for evaluating functional health in our setting. The dispersion of FSS values underlines the poor accuracy of POPC-PCPC compared to the new FSS scale, which is more disaggregated and objective.

Effect of protamine in obesity induced by high-fat diets in rats.

OBJECTIVE: Protamine has been shown to have an inhibitory effect on protein lipase in vitro; the objective of this study was to evaluate the antiobesity activity effect of protamine in obese induced rats, and to evaluate the effect of protamine on postprandial hypertriacylglyceridemia in rats by intragastric administration of a lipid emulsion containing corn oil. DESIGN: Two experiments were carried out: (1) In a parallel study in rats, we administered a lipid emulsion containing corn oil plus 0, 200 or 500 mg kg(-1) of protamine intragastrically. (2) In a randomized parallel prospective rats experiment, rats were fed with a high-fat diet and 0, 200 or 500 mg of protamine per kg of animal weight during 5 weeks. SUBJECTS: Male Sprague-Dawley rats. MEASUREMENTS: In experiment 1, plasma triacylglycerol levels after oral administration of lipid emulsion were determined. In experiment 2, weight gain, concentrations of plasma triacylglycerol, plasma total cholesterol and albumin were determined, and the subcutaneous and visceral adipose tissues were weighed. RESULTS: Plasma triacylglycerol concentration in rats administered with 200 or 500 mg kg(-1) of protamine was significantly lower than that in rats in the control group (200 mg kg(-1) of protamine, P<0.05 at 1, 2, 3 and 4 h; 500 mg kg(-1) of protamine P<0.05 at 2, 3 and 4 h). In rats fed with a high-fat diet, and 200 and 500 mg kg(-1) of protamine, there was a decreased body weight gain by 52 and 66 g, respectively, reduced visceral fat by 5 and 8 g, respectively and subcutaneous tissue weights by 12 and 15 g, respectively. Plasma triacylglycerol was 17 and 45 mg per 100 ml lower in rats fed with high-fat diet plus 200 and 500 mg kg(-1) of protamine, respectively. And cholesterol concentrations were 18 and 22 mg per 100 ml lower in both protamine groups, respectively. CONCLUSION: Our study demonstrates that protamine reduce weight gain and body fat accumulation through the inhibition of dietary fat absorption.