Nanostructured gadolinium(III) micelles: Synthesis, characterization, cytotoxic activities, and MRI applications in vivo.

Gadolinium-based contrast agents (GBCAs) are used in around 40 % of MRI procedures. Despite initial perceptions of minimal risk, their long-term use has emphasized the need to reduce toxicity and develop more efficient GBCAs with extended blood retention. Advancements in nanomaterials have led to improved GBCAs, enhancing MRI diagnostics. This study synthesizes and characterizes nanostructured gadolinium(III) micelles as superior MRI contrast agents. The complexes, [Gd(L)2], where L is a ligand of the N-alkyl-N-methylglucamine surfactant series (L8, L10 or L12, L10), form nanostructured micelles in aqueous solution. Gd(L8)2 and Gd(L10)2 relaxivities remained stable across concentrations. Compared to Gd-DTPA, Gd(III) micelles showed enhanced T1-weighted MRI contrast. Gd(L12)2 micelles exhibited cytotoxicity against B16F10 melanoma cells (IC50 42.5 ± 2.2 µM) and L292L929 fibroblasts (IC50 52.0 ± 2.5 µM), with a selectivity index of 1.2. In vivo application in mice brain T2-weighted images suggests nanostructured Gd(III) micelles are promising MRI contrast agents for targeting healthy organs or tumors.

Adult brain activation in response to pain is changed by neonatal painful stimulation according to sex: A manganese-enhanced MRI study.

Although it is known that nociceptive stimulation in the first postnatal week in rats is useful to model preterm pain, resulting in activation of specific brain areas, as assessed in vivo using manganese-enhanced magnetic resonance imaging (MEMRI), little is known about its long-term effects and sex specificity. Here we aimed to investigate whether inflammatory pain induced in male and female adult rats modify the pattern of brain activation between animals subjected or not to neonatal pain. For this, Complete Freund's adjuvant (CFA) was injected into the left hind paw of rat pups on postnatal day 1 (P1) or P8 to induce inflammatory response. During adulthood, CFA-treated and control animals were injected with CFA 1 hr prior MRI. MEMRI has the ability to enhance the contrast of selective brain structures in response to a specific stimulus, as the pain. MEMRI responses were consistent with activation of nociceptive pathways and these responses were reduced in animals treated with CFA on P1, but increased in animals treated on P8, mainly in the female group. In agreement, P8 female group showed exacerbated responses in the thermal nociceptive test. Using MEMRI, we conclude that the natural ability of adult rats to recognize and react to pain exposition is modified by neonatal painful exposition, mainly among females.

Contrast optimization in arterial spin labeling with multiple post-labeling delays for cerebrovascular assessment.

OBJECTIVE: Improving the readout for arterial spin labeling with multiple post-labeling delays (multi-PLD ASL) through a flip angle (FA) sweep towards increasing contrast-to-noise ratio for long PLD images. METHODS: Images were acquired from 20 healthy subjects and 14 patients with severe, asymptomatic carotid artery stenosis (ACAS) in a 3T MRI scanner. Multi-PLD ASL images with conventional and proposed (FA sweep) readouts were acquired. For patients, magnetic resonance angiography was used to validate the multi-PLD ASL results. Perfusion values were calculated for brain regions irrigated by the main cerebral arteries and compared by analysis of variance. RESULTS: For healthy subjects, better contrast was obtained for long PLDs when using the proposed multi-PLD method compared to the conventional. For both methods, no hemispheric difference of perfusion was observed. For patients, the proposed method facilitated the observation of delayed tissue perfusion, which was not visible for long PLD using the conventional multi-PLD ASL. CONCLUSION: We successfully assessed brain perfusion of patients with asymptomatic CAS using multi-PLD ASL with FA sweep. We were able to show subtle individual differences. Moreover, prolonged arterial transit time in patients was observed, although they were considered asymptomatic, suggesting that it may not be an adequate term to characterize them.

Dracunculiasis in a domestic dog in Brazil.

We report and discuss the surprising encounter of a dog naturally infected by Dracunculus sp. in Brazil, a brief clinical history of the animal and a procedure for removing the nematode. We also present details on the morphology of the fragments collected from the nematode and a phylogenetic comparison of the partial sequences of the mitochondrial 18S rRNA and cytochrome c oxidase subunit I (COI) genes, deposited with others in GenBank. The samples were an independent lineage forming a well-supported monophyletic assemblage with D. medinensis. We thus conclude that this species has not yet been sequenced or even described and will only be elucidated by more information because only two species of Dracunculus have been reported in Brazil, D. fuelleborni and D. brasiliensis.

Three new species of Anacanthorus Mizelle & Price, 1965 (Monogenea: Dactylogyridae) from Markiana nigripinnis Perugia (Actinopterygii: Characidae) in Pantanal wetlands, Brazil.

Three monogenean species, Anacanthorus luquei n. sp., A. scholzi n. sp. and A. cohenae n. sp. are described from the gills of the tetra fish Markiana nigripinnis (Perugia) (Characidae), collected in the Pantanal wetlands, State of Mato Grosso do Sul, Brazil. Among other differences, Anacanthorus luquei n. sp. differs from the most morphologically similar species, based on the structure of the accessory piece as follows: branches with smooth margins (vs with irregular margins in A. cuticulovaginus), without pointed projections at distal end (vs with projections in A. dipelecinus) and with 2 branches (vs 3 in A. quinqueramus). Anacanthorus scholzi n. sp. is most morphologically similar to A. luquei n. sp., differing from it because one of the branches of the accessory piece is bifurcated at the distal portion. Anacanthorus cohenae n. sp. can be differentiated from the congeners based on the combination of the following features: MCO cylindrical and robust with sclerotised flanges on the extremities, accessory piece V-shaped, bearing two branches similar in length and with blunt distal ends, and hooks with a proximal bulb. This is the first parasitological study on M. nigripinnis and, currently, Anacanthorus allocates 88 species infesting characiform fishes in the Neotropical region, including the three new species described here.

Preperitoneal fat as a non-invasive marker of increased risk of severe non-alcoholic fatty liver disease in patients with type 2 diabetes.

BACKGROUND AND AIM: Fat distribution may have prognostic value in the evaluation of non-alcoholic fatty liver disease. This study was conducted to evaluate associations of magnetic resonance imaging-measured abdominal fat areas with steatosis, steatohepatitis, and fibrosis, assessed histopathologically, in patients with type 2 diabetes. METHODS: This prospective study included 66 patients with type 2 diabetes (12 males, 54 females, age 26-68 years), without chronic liver disease of other causes. Axial dual-echo magnetic resonance images were acquired. Visceral, subcutaneous, and preperitoneal fat areas were measured using Osirix software. Liver biopsy specimens were obtained from all patients and examined histopathologically to evaluate steatosis, steatohepatitis, and fibrosis. Linear (for steatosis) and logistic (for steatohepatitis and fibrosis) regression models were fitted for the outcomes. R2 was used as a measure of how much model variance the predictors explained and to compare different predictors of the same outcome. RESULTS: Visceral and preperitoneal fat areas correlated well with histopathologically determined liver steatosis grade (both P = 0.004) and liver fibrosis (P = 0.008 and P = 0.037, respectively). All fat areas correlated well with steatohepatitis (P ≤ 0.002). Preperitoneal and visceral fat areas were the best predictors of steatohepatitis (R2 = 0.379) and fibrosis (R2 = 0.181), respectively. CONCLUSIONS: Visceral fat area was the best predictor of fibrosis in patients with type 2 diabetes. Preperitoneal fat area was the best predictor of steatohepatitis and is a potential new non-invasive marker for use in the screening of these patients to detect more aggressive forms of non-alcoholic fatty liver disease.

Midfemoral Bone Volume of Walking Subjects with Chronic Hemiparesis Post Stroke.

BACKGROUND AND PURPOSE: Muscle and bone form a functional unit. Residual physical poststroke impairments such as muscle weakness, spasticity, and decrease in function can promote metabolic bone changes. Moreover, muscle strength can influence this process. Thus, the purpose of the present study was to investigate bone volume and mobility performance in subjects with chronic hemiparesis post stroke. METHODS: A cross-sectional study was performed on 14 subjects post stroke who were paired with healthy controls. Bone volume, isometric muscle performance, and mobility levels were measured. Midfemoral bone volumes were determined using magnetic resonance imaging, and muscular performance was measured by dynamometry. Mobility was measured using the Timed Up and Go Test and the 10-Meter Walk Test. RESULTS: Regarding bone volume total, there was no difference in the medullary and cortical groups (P ≥ .05). During torque peak isometric flexion, the paretic group was significantly different compared with the other groups (P = .001). However, the control presented no difference compared with the nonparetic limb (P = .40). With regard to the extension isometric torque peak, the paretic limb was significantly different compared with the nonparetic (P = .033) and the control (P = .001) limbs, and the control was different from the nonparetic limb (P = .045). Bone volume variables correlated with the isometric torque peak. CONCLUSIONS: Chronic hemiparetic subjects maintain bone geometry compared with healthy volunteers matched by age, body mass index, and gender. The correlation between bone volume midfemoral structures and knee isometric torque was possible.

Hepatozoon caimani Carini, 1909 (Adeleina: Hepatozoidae) in wild population of Caiman yacare Daudin, 1801 (Crocodylia: Alligatoridae), Pantanal, Brazil.

Previous studies showed infections of Hepatozoon caimani in wild populations of caimans in wide regions from Brazil; some of those demonstrated that trophic chain are linked to natural infections through paratenic hosts or by the direct ingestion of vectors. These studies life cycle of H. caimani contributed inestimably to the knowledge of transmission routes, yet but lack enhancement tools for better detail of parasite. This study reports the forms in the blood and tissues, and also partial molecular characterization of the H. caimani following part of the 18S rRNA region. In the southern Pantanal, there were sampling 39 adult caimans (Caiman yacare), where 31 (79.5%) were parasitized by H. caimani. Free gametocytes had an average intensity of 19.6% and intraerythrocytic forms 7.42%, in the blood smears. In stained smears of the liver and lungs of naturally infected caimans which were examined, monozoic and dizoic cysts were found in these tissues, generally next to the vessels. In the histopathology, meronts were observed in the wall of vessels from liver and kidney ducts. Blood samples were forwarded to PCR process and produced amplicons with about 600 and 900 bp, respectively, for the primers HEPF300/HEP900 and HEMO1/HEMO2. This was the first report of molecular confirmation of Hepatozoon in populations of naturally infected caimans of morphological detail of the gametocytes in scanning electron microscopy and histology of merogony in livers and kidneys of C. yacare.

Functional dissociation of ventral frontal and dorsomedial default mode network components during resting state and emotional autobiographical recall.

Humans spend a substantial share of their lives mind-wandering. This spontaneous thinking activity usually comprises autobiographical recall, emotional, and self-referential components. While neuroimaging studies have demonstrated that a specific brain "default mode network" (DMN) is consistently engaged by the "resting state" of the mind, the relative contribution of key cognitive components to DMN activity is still poorly understood. Here we used fMRI to investigate whether activity in neural components of the DMN can be differentially explained by active recall of relevant emotional autobiographical memories as compared with the resting state. Our study design combined emotional autobiographical memory, neutral memory and resting state conditions, separated by a serial subtraction control task. Shared patterns of activation in the DMN were observed in both emotional autobiographical and resting conditions, when compared with serial subtraction. Directly contrasting autobiographical and resting conditions demonstrated a striking dissociation within the DMN in that emotional autobiographical retrieval led to stronger activation of the dorsomedial core regions (medial prefrontal cortex, posterior cingulate cortex), whereas the resting state condition engaged a ventral frontal network (ventral striatum, subgenual and ventral anterior cingulate cortices) in addition to the IPL. Our results reveal an as yet unreported dissociation within the DMN. Whereas the dorsomedial component can be explained by emotional autobiographical memory, the ventral frontal one is predominantly associated with the resting state proper, possibly underlying fundamental motivational mechanisms engaged during spontaneous unconstrained ideation.

Haemogregarina spp. in a wild population from Podocnemis unifilis Troschel, 1848 in the Brazilian Amazonia.

The study objectives were to characterize the morphology of the parasitic forms and describe the prevalence and intensity of Haemogregarina spp. in a population of the turtle Podocnemis unifilis as well as to examine the relationships between parasitism and turtle variables such as gender, size, and weight. Samples were taken in the Tapajós and Jamanxim rivers, Itaituba, Pará state, Brazil. Blood was collected from the tail vein of 72 P. unifilis specimens, including 35 males, 36 females, and one unsexed juvenile. The prevalence of Haemogregarina spp. was 98% (n = 71). The mean parasite intensity of Haemogregarina spp. was 118 (1-582) parasites/2000 blood cells (6%). There was no significant difference in the mean parasite intensity between male (137.68 ± 121.8, n = 35) and female turtles (101.42 ± 123.59, n = 35). There was no relationship between parasite intensity and carapace length. Although the relationship between parasite intensity and host body weight was significant, the relationship was weak. This is the first study on Haemogregarina parasitism with a relatively high number of turtles in Brazil.

Are fish paratenic natural hosts of the caiman haemoparasite Hepatozoon caimani?

The susceptibility of two fish and four mosquito species to the Caiman yacare haemoparasite Hepatozoon caimani was experimentally investigated. Mosquitoes belonging to four species (Aedes fluviatilis, Aedes albopictus, Aedes aegypti and Culex quinquefasciatus) were blood-fed on two naturally infected C. yacare from the Central-West Region of Brazil that exhibited distinct levels of parasitaemia: caimans A (11.05%) and B (1.25%). None of the engorged A. fluviatilis, A. albopictus or A. aegypti mosquitoes fed on caiman A survived for the duration of the sporogonic cycle; the great majority of the engorged mosquitoes died within 48 h of the blood meal. All A. aegypti fed on caiman B were negative, whereas 91.3% of dissected C. quinquefasciatus fed on the same caiman contained oocysts. Characid fish-Metynnis sp. and Astyanax sp.-were individually fed with C. quinquefasciatus females previously engorged (21-23 days) on caiman B. No parasite was found in the Astyanax fish. By contrast, 100% of the Metynnis fish depicted numerous cysts harbouring cystozoites identical to those of H. caimani, even more than 8 months after the ingestion of the infected mosquitoes. The cysts were located near the veins of the liver and, in some cases, close to the tunica intima of these vessels. No inflammatory reaction was observed. Gametocytes were observed in the blood smears of juvenile caimans that had ingested infected fish 9-12 weeks earlier. The potential role of fish as paratenic vertebrate hosts of H. caimani in nature is discussed.

New insights into a poorly known parasite, Dero lutzi (Oligochaeta: Naididae), associated with tree frogs of the genus Scinax: morphological evaluation and genotypic data.

The oligochaete Dero lutzi follows a life strategy that alternates between free-living periods in aquatic environments and endoparasitic phases. Most occurrences of D. lutzi in anurans are reported in species with arboreal habits, with studies limited to the recording of the oligochaete's presence in the host. Our study recovered specimens of D. lutzi from the tree frogs Scinax fuscovarius and Scinax. nasicus. We performed a morphological assessment of the parasite using light microscopy, for the first time, scanning electron microscopy. Molecular characterization of D. lutzi was carried out using the mitochondrial gene 16S rRNA and the nuclear gene 28S rRNA. Additionally, a phylogenetic tree was constructed to assess the species´position in relation to other group members. In our results, we confirmed the phenotypic morphological characteristics of the endoparasitic phase of D. lutzi. We also presented its phylogenetic position with other oligochaetes in the group, demonstrating the proximity between the endoparasite D. lutzi and the free-living oligochaete D. superterrenus.

Phylogenetic position inferred on SSU rDNA sequence gene and description of a new parasitic cnidarian (Endocnidozoa: Myxobolidae) infecting Markiana nigripinnis (Teleostei: Stevardiinae) from a small marginal lake floodplain, Brazil.

Herein, a detailed molecular phylogeny analysis was developed to determine the phylogenetic position of a new freshwater histozoic myxosporean cnidarian, Henneguya markiana sp. nov. from the world's largest tropical wetland area, Pantanal, Brazil. The new species is described using an integrative taxonomy approach including morphology, biological traits and molecular data. Phylogenetic analysis inferred by Maximum Likehood method showed the new Henneguya species in a well-supported clade of myxosporean gill parasites of South American characids fishes. In this same clade, the new Henneguya described appeared in a sub-clade clustering with H. lacustris and H. chydadea. Nevertheless, the sequences of the new species and H. lacustris and H. chydadea have a large genetic divergence of 10.4% (148 nucleotides-nt) and 10.5% (147 nt) respectively. To the best of our knowledge, this is the first report of a cnidarian myxosporean species parasitizing a fish from Stevardiinae from South America. In the light of the differences observed from the integrative taxonomy, we are confident that this isolate is a new species of Henneguya, increasing the knowledge of diversity of this enigmatic group of cnidarians.

Survey the Occurrence of Globocephalus urosubulatus (Nematoda: Ancylostomatidae) in Wild Boars (Sus scrofa) in the State of São Paulo, Brazil.

Although previous studies have characterized the helminth fauna of wild boars kept in captivity in Brazil, records on these helminths in free-ranging animals are still scarce. In view of this, we aimed in our work to investigate the occurrence and morphological and morphometric characteristics of gastrointestinal helminths in wild Sus scrofa from the northwest region of the State of São Paulo, Brazil. The digestive systems of 10 animals (5 males and 5 females of different ages) were used in this study. Each anatomical segment was washed and sieved under running water, and the helminths were separated and identified using light and scanning electron microscopy, according to their morphological characteristics. A total of 2750 (1152 males and 1598 females) nematode specimens were collected from the small intestine of these wild boars, and all of them presented the morphological characteristics of Globocephalus urosubulatus. However, one characteristic is of particular interest because it has not yet been reported in the literature: a marked asymmetry between the lobes and their respective rays of the copulatory bursa, with the left one being larger than the right one. In this research, we identified the presence of G. urosubulatus in all the examined free-ranging wild boars and reported for the first time in the literature the asymmetry in the copulatory bursa.

A neural signature of affiliative emotion in the human septohypothalamic area.

Comparative studies have established that a number of structures within the rostromedial basal forebrain are critical for affiliative behaviors and social attachment. Lesion and neuroimaging studies concur with the importance of these regions for attachment and the experience of affiliation in humans as well. Yet it remains obscure whether the neural bases of affiliative experiences can be differentiated from the emotional valence with which they are inextricably associated at the experiential level. Here we show, using functional MRI, that kinship-related social scenarios evocative of affiliative emotion induce septal-preoptic-anterior hypothalamic activity that cannot be explained by positive or negative emotional valence alone. Our findings suggest that a phylogenetically conserved ensemble of basal forebrain structures, especially the septohypothalamic area, may play a key role in enabling human affiliative emotion. Our finding of a neural signature of human affiliative experience bears direct implications for the neurobiological mechanisms underpinning impaired affiliative experiences and behaviors in neuropsychiatric conditions.

[A methodology to implement preventive actions against harmful drug use in the context of primary health care in Latin America]. / Metodologia de implementação de práticas preventivas ao uso de drogas na atenção primária latino-americana.

OBJECTIVE: To develop a methodology to implement practices of prevention against the use of alcohol and other drugs in the context of primary health care (PHC) that will contribute to the debate about policies and actions in Latin American countries. METHODS: This intervention research project was carried out in a small/medium-sized Brazilian city. The development process was assessed through participant observation with the aim of adapting the methodology to local needs and identifying existing weaknesses and strengths with impact on implementation. RESULTS: A model was developed with six stages: initial contact and planning, diagnosis and mapping, sensitization, training, follow-up, and communication of results to participants. The following weaknesses were identified: limitation of resources (human, financial, infrastructural), limitations in the coverage and comprehensiveness of the assistance network, poor participation from physicians, training based on medicalized care, insufficient participation of health care management, insufficient involvement and participation of civil society, and few opportunities for participation of the population in the planning and execution of public policies. Strengths included the participation of community health agents and nurses in applying, organizing, and planning initiatives, in addition to the organization of educative and preventive actions in schools and communities by health care teams, suggesting that it is possible to implement screening, brief intervention, and referral to treatment (SBIRT) initiatives in the context of PHC in Latin America. CONCLUSIONS: The methodology developed in this study can be useful for Latin American countries if local needs are taken into consideration. It should be noted, however, that results will only be observed in the mid- to long term, rather than strictly in the short term.

Amblyomma sculptum ticks on a giant otter from the Brazilian Pantanal.

The giant otter (Pteronura brasiliensis) is a semiaquatic carnivore and a top predator in the trophic chain, considered a sentinel of freshwater ecosystems. Ticks are common ectoparasites of worldwide distribution and potential vectors of diseases. In this study, we report the ectoparasitism by ticks on a giant otter carcass found during monitoring activity at the Negro River, that holds a viable population of this endangered species in the Brazilian Pantanal. A total of three tick specimens were collected: two adults were identified as Amblyomma sculptum and a nymph as Amblyomma spp. There is a lack of information about the health of free-ranging giant otters and this report contributes to elucidate some of the host-parasite relationships, although much more research is needed to expand the knowledge about which kinds of pathogens are circulating in the species, especially among those transmitted by ticks.

A Combination of Ex Vivo and In Vivo Strategies for Evaluating How Much New Oral Anticoagulants Exacerbate Experimental Intracerebral Bleeding.

Background Intracerebral hemorrhage is the most serious complication of anticoagulant therapy but the effects of different types of oral anticoagulants on the expansion of these hemorrhages are still unclear. Clinical studies have revealed controversial results; more robust and long-term clinical evaluations are necessary to define their outcomes. An alternative is to test the effect of these drugs in experimental models of intracerebral bleeding induced in animals. Aims To test new oral anticoagulants (dabigatran etexilate, rivaroxaban, and apixaban) in an experimental model of intracerebral hemorrhage induced by collagenase injection into the brain striatum of rats. Warfarin was used for comparison. Methods Ex vivo anticoagulant assays and an experimental model of venous thrombosis were employed to determine the doses and periods of time required for the anticoagulants to achieve their maximum effects. Subsequently, volumes of brain hematoma were evaluated after administration of the anticoagulants, using these same parameters. Volumes of brain hematoma were evaluated by magnetic resonance imaging, H&E (hematoxylin and eosin) staining, and Evans blue extravasation. Neuromotor function was assessed by the elevated body swing test. Results and Conclusions The new oral anticoagulants did not increase intracranial bleeding compared with control animals, while warfarin markedly favored expansion of the hematomas, as revealed by magnetic resonance imaging and H&E staining. Dabigatran etexilate caused a modest but statistically significant increase in Evans blue extravasation. We did not observe significant differences in elevated body swing tests among the experimental groups. The new oral anticoagulants may provide a better control over a brain hemorrhage than warfarin.

Manganese-enhanced magnetic resonance imaging detects mossy fiber sprouting in the pilocarpine model of epilepsy.

PURPOSE: Mossy fiber sprouting (MFS) is a frequent finding following status epilepticus (SE). The present study aimed to test the feasibility of using manganese-enhanced magnetic resonance imaging (MEMRI) to detect MFS in the chronic phase of the well-established pilocarpine (Pilo) rat model of temporal lobe epilepsy (TLE). METHODS: To modulate MFS, cycloheximide (CHX), a protein synthesis inhibitor, was coadministered with Pilo in a subgroup of animals. In vivo MEMRI was performed 3 months after induction of SE and compared to the neo-Timm histologic labeling of zinc mossy fiber terminals in the dentate gyrus (DG). KEY FINDINGS: Chronically epileptic rats displaying MFS as detected by neo-Timm histology had a hyperintense MEMRI signal in the DG, whereas chronically epileptic animals that did not display MFS had minimal MEMRI signal enhancement compared to nonepileptic control animals. A strong correlation (r = 0.81, p < 0.001) was found between MEMRI signal enhancement and MFS. SIGNIFICANCE: This study shows that MEMRI is an attractive noninvasive method for detection of mossy fiber sprouting in vivo and can be used as an evaluation tool in testing therapeutic approaches to manage chronic epilepsy.