Diagnosing dementia and normal aging: clinical relevance of brain ratios and cognitive performance in a Brazilian sample

The main objective of the present study was to evaluate the diagnostic value (clinical application) of brain measures and cognitive function. Alzheimer and multiinfarct patients (N = 30) and normal subjects over the age of 50 (N = 40) were submitted to a medical, neurological and cognitive investigation. The cognitive tests applied were Mini-Mental, word span, digit span, logical memory, spatial recognition span, Boston naming test, praxis, and calculation tests. The brain ratios calculated were the ventricle-brain, bifrontal, bicaudate, third ventricle, and suprasellar cistern measures. These data were obtained from a brain computer tomography scan, and the cutoff values from receiver operating characteristic curves. We analyzed the diagnostic parameters provided by these ratios and compared them to those obtained by cognitive evaluation. The sensitivity and specificity of cognitive tests were higher than brain measures, although dementia patients presented higher ratios, showing poorer cognitive performances than normal individuals. Normal controls over the age of 70 presented higher measures than younger groups, but similar cognitive performance. We found diffuse losses of tissue from the central nervous system related to distribution of cerebrospinal fluid in dementia patients. The likelihood of case identification by functional impairment was higher than when changes of the structure of the central nervous system were used. Cognitive evaluation still seems to be the best method to screen individuals from the community, especially for developing countries, where the cost of brain imaging precludes its use for screening and initial assessment of dementia.

Fluid dynamic modelling and simulation of circulating fluidized bed reactors: importance of the interface turbulence transfer

The main objective of this work is to analyze the importance of the gas-solid interface transfer of the kinetic energy of the turbulent motion on the accuracy of prediction of the fluid dynamic of Circulating Fluidized Bed (CFB) reactors. CFB reactors are used in a variety of industrial applications related to combustion, incineration and catalytic cracking. In this work a two-dimensional fluid dynamic model for gas-particle flow has been used to compute the porosity, the pressure, and the velocity fields of both phases in 2-D axisymmetrical cylindrical co-ordinates. The fluid dynamic model is based on the two fluid model approach in which both phases are considered to be continuous and fully interpenetrating. CFB processes are essentially turbulent. The model of effective stress on each phase is that of a Newtonian fluid, where the effective gas viscosity was calculated from the standard k-epsilon turbulence model and the transport coefficients of the particulate phase were calculated from the kinetic theory of granular flow (KTGF). This work shows that the turbulence transfer between the phases is very important for a better representation of the fluid dynamics of CFB reactors, especially for systems with internal recirculation and high gradients of particle concentration. Two systems with different characteristics were analyzed. The results were compared with experimental data available in the literature. The results were obtained by using a computer code developed by the authors. The finite volume method with collocated grid, the hybrid interpolation scheme, the false time step strategy and SIMPLEC (Semi-Implicit Method for Pressure Linked Equations - Consistent) algorithm were used to obtain the numerical solution.

Validation of a simple and inexpensive method for the quantitation of infarct in the rat brain

A gravimetric method was evaluated as a simple, sensitive, reproducible, low-cost alternative to quantify the extent of brain infarct after occlusion of the medial cerebral artery in rats. In ether-anesthetized rats, the left medial cerebral artery was occluded for 1, 1.5 or 2 h by inserting a 4-0 nylon monofilament suture into the internal carotid artery. Twenty-four hours later, the brains were processed for histochemical triphenyltetrazolium chloride (TTC) staining and quantitation of the schemic infarct. In each TTC-stained brain section, the ischemic tissue was dissected with a scalpel and fixed in 10% formalin at 0ºC until its total mass could be estimated. The mass (mg) of the ischemic tissue was weighed on an analytical balance and compared to its volume (mm³), estimated either by plethysmometry using platinum electrodes or by computer-assisted image analysis. Infarct size as measured by the weighing method (mg), and reported as a percent (%) of the affected (left) hemisphere, correlated closely with volume (mm³, also reported as %) estimated by computerized image analysis (r = 0.88; P < 0.001; N = 10) or by plethysmography (r = 0.97-0.98; P < 0.0001; N = 41). This degree of correlation was maintained between different experimenters. The method was also sensitive for detecting the effect of different ischemia durations on infarct size (P < 0.005; N = 23), and the effect of drug treatments in reducing the extent of brain damage (P < 0.005; N = 24). The data suggest that, in addition to being simple and low cost, the weighing method is a reliable alternative for quantifying brain infarct in animal models of stroke.

Interface between Intellectual Disability and Mental Health: hermeneutic review

A literature review was conducted aiming to understand the interface between the Intellectual Disability and Mental Health fields and to contribute to mitigating the path of institutionalizing individuals with intellectual deficiencies. The so-called dual diagnosis phenomenon remains underestimated in Brazil but is the object of research and specific public policy internationally. This phenomenon alerts us to the prevalence of mental health problems in those with intellectual disabilities, limiting their social inclusion. The findings reinforce the importance of this theme and indicate possible diagnostic invisibility of the development of mental illness in those with intellectual disabilities in Brazil, which may contribute to sustaining psychiatric institutionalization of this population. 

Studies on human anti-rabies immunization in Brazil: II - Preliminary evaluation of the 2-1-1 schedule for human pre-exposure anti-rabies immunization, employing suckling mouse brain vaccine

This study reports preliminary results of virus neutralizing antibody (VNA) titers obtained on different days in the course of human anti-rabies immunization with the 2-1-1 schedule (one dose is given in the right arm and one dose in the left arm at day 0, and one dose is apllied on days 7 and 21), recommended by WHO for post-exposure treatment with cell culture vaccines. A variant schedule (double dose on day zero and another on day 14) was also tested, both employing suckling mouse brain vaccine. A complete seroconversion rate was obtained after only 3 vaccine doses, and almost all patients (11 of 12) presented titers higher than 1.0 IU/ml. Both neutralizing response and seroconversion rates were lower in the group receiving only 3 doses, regardless of the sample collecting day. Although our results are lower than those found with cell culture vaccines, the geometry mean of VNA is fully satisfactory, overcoming the lower limit recommended by WHO of 0.5 IU/ml. The 2-1-1 schedule could be an alternative one for pre exposure immunization, shorter than the classical 3+1 regimen (one dose on days 0, 2, 4 and 30) with only three visits to the doctor, instead of four.

AN ELISA SUITABLE FOR THE DETECTION OF RABIES VIRUS ANTIBODIES IN SERUM SAMPLES FROM HUMAN VACCINATED WITH EITHER CELL-CULTURE VACCINE OR SUCKLING-MOUSE-BRAIN VACCINE

An indirect ELISA for determination of post-vaccination rabies antibody was applied. Purified rabies virus was used as antigen to coat plates, and staphylococcal protein A linked with horseradish peroxidase was used for detecting IgG antibody in human sera. Sera from humans, vaccinated with cell-culture vaccine or suckling-mouse-brain vaccine, were examined. ELISA results were compared to those obtained from the virus neutralization test. The mean and standard deviation of OD were determined for 126 negative sera (pre-vaccination) and for 73 sera from vaccinated persons showing antibody titers lower than 0.5 IU/ml. Results were defined as ELISA -positive, -negative or -doubtful. Establishment of a doubtful region reduced the number of sera otherwise classified as positive (false-positive sera). In this way, the sensitivity, specificity and agreement values were respectively 87.5%, 92.4% and 88.5%. No significant differences were observed in these values when the group vaccinated with cell-culture vaccine and the group vaccinated with suckling-mouse-brain vaccine were compared. It was shown that much of the disagreement between the values obtained by neutralization test and ELISA occurred in sera obtained at the beginning of the immunization process, and was probably due to the presence of IgM in the serum samples, detected only by the former test. This ELISA method can be used as a screening test in rabies laboratories regardless of the kind of vaccine used for immunization.

Tuberculous brain abscess in a patient with AIDS: case report and literature review

Tuberculous brain abscesses in AIDS patients are considered rare with only eight cases reported in the literature. We describe the case of a 34-year-old woman with AIDS and previous toxoplasmic encephalitis who was admitted due to headache and seizures. A brain computed tomography scan disclosed a frontal hypodense lesion with a contrast ring enhancement. Brain abscess was suspected and she underwent a lesion puncture through a trepanation. The material extracted was purulent and the acid-fast smear was markedly positive. Timely medical and surgical approaches allowed a good outcome. Tuberculous abscesses should be considered in the differential diagnosis of focal brain lesions in AIDS patients. Surgical excision or stereotactic aspiration, and antituberculous treatment are the mainstay in the management of these uncommon lesions.

Multiple brain abscesses due to Penicillium spp infection

We present a case of central nervous system (CNS) infection by a member of the Penicillium genera in a HIV-negative man in Brazil. The patient was admitted complaining of loss of visual fields and speech disturbances. CT scan revealed multiple brain abscesses. Stereothacic biopsies revealed fungal infection and amphotericin B treatment begun with initial improvement. The patient died few days later as a consequence of massive gastrointestinal bleeding due to ruptured esophageal varices. The necropsy and final microbiologic analyses disclosed infection by Penicillium sp. There are thousands of fungal species of the Penicillium genera. Systemic penicilliosis is caused by the P. marneffei and was formerly a rare disease, but now is one of the most common opportunistic infection of AIDS patients in Southeast Asia. The clinical presentation usually involves the respiratory system and the skin, besides general symptoms like fever and weight loss. Penicillium spp infection caused by species other than P. marneffei normally cause only superficial or allergic disease but rare cases of invasive disease do occur. We report the fourth case of Penicillium spp CNS infection.

Brain abscess secondary to frontal osteomyelitis

Frontal osteomyelitis is a rare complication of sinusitis. Common intracranial complications of the frontal osteomyelitis are meningitis, epidural empyema, subdural empyema and brain abscess. We described a case of frontal osteomyelitis with brain abscess caused by Staphylococcus aureus with improve after needle aspiration and antibiotics to brain abscess for eight weeks and for chronic osteomyelitis for four months.

Cryptococcus gattii fungemia: report of a case with lung and brain lesions mimicking radiological features of malignancy

A 64-year-old apparently immunocompetent white man developed lung and brain lesions of disseminated cryptococcosis. The radiologic features mimicked those of lung cancer metastatic to the central nervous system. C. gattii was recovered from cultures of bronchoalveolar lavage fluid, brain biopsy, and blood. The same fungus was recovered from pulmonary and brain specimens at autopsy. Serum and cerebrospinal fluid cryptococcal antigen tests were diagnostic in our case and should be included in the diagnostic evaluation of unexplained pulmonary and cerebral lesions. A literature search showed few reports of fungemia by this species of Cryptococcus, contrasting to C. neoformans.

Portal cd4+ and cd8+ t lymphocyte correlate to intensity of interface hepatitis in chronic hepatitis C

BACKGROUND: The pathogenesis of chronic hepatitis C is still a matter of debate. CD4+ and CD8+ T lymphocytes (TL) are typically observed within the portal and periportal spaces of affected livers, but their functional role in hepatitis C progression has not been fully elucidated. METHODS: CD4+ and CD8+ TL were quantified by immunohistochemistry in portal and periportal spaces of 39 liver biopsies from patients with chronic hepatitis C. They were associated to demographic data, histological parameters, laboratory findings of patients and hepatitis C genotypes. RESULTS: There was high numbers of CD4+ and CD8+ TL from which the density of CD4+ T was higher than CD8+ TL in portal and periportal spaces. CD4+ and CD8+ TL were directly correlated to intensity of interface hepatitis. CD8+ TL correlated to serum enzyme levels. CONCLUSION: The high numbers of CD4+ and CD8+ TL in portal and periportal spaces and their correlation to interface hepatitis suggest that hepatitis C evolution depends on the action of intrahepatic T lymphocytes, lending support to the notion of an immune-mediated mechanism in the pathogenesis of chronic hepatitis C.

Astrocytic and microglial response and histopathological changes in the brain of horses with experimental chronic Trypanosoma evansi infection

This study aimed to characterize astrocytic and microglial response in the central nervous system (CNS) of equines experimentally infected with T. evansi. The experimental group comprised males and females with various degrees of crossbreeding, ages between four and seven years. The animals were inoculated intravenously with 10(6) trypomastigotes of T. evansi originally isolated from a naturally infected dog. All equines inoculated with T. evansi were observed until they presented symptoms of CNS disturbance, characterized by motor incoordination of the pelvic limbs, which occurred 67 days after inoculation (DAI) and 124 DAI. The animals in the control group did not present any clinical symptom and were observed up to the 125th DAI. For this purpose the HE histochemical stain and the avidin biotin peroxidase method was used. Lesions in the CNS of experimentally infected horses were those of a wide spread non suppurative meningoencephalomyelitis.The severity of lesions varied in different parts of the nervous system, reflecting an irregular distribution of inflammatory vascular changes. The infiltration of mononuclear cells was associated with anisomorphic gliosis and reactive microglia was identified. The intensity of the astrocytic response in the CNS of the equines infected by T. evansi characterizes the importance of the performance of these cells in this trypanosomiasis. The characteristic gliosis observed in the animals in this experiment suggests the ability of these cells as mediators of immune response. The parasite, T. evansi, was not identified in the nervous tissues.