Clinical correlates of olfactory dysfunction in spinocerebellar ataxia type 3

Olfactory dysfunction is a very common and early sign in neurodegenerative disorders, but few data are already available in hereditary ataxias. Our aim was to evaluate the sense of smell in patients with molecular-proven spinocerebellar ataxia type 3 (SCA3). Forty-one patients with SCA3 and 46 control subjects were studied. The sense of smell was tested using the Sniffin's Sticks (SS-16). We also evaluated Mini-Mental State Examination (MMSE) and non-cerebellar symptoms, such as parkinsonism, dystonia, and restless legs syndrome (RLS). The SCA3 group had significantly lower SS-16 scores than controls (11.5 ± 2.4 vs 12.8 ± 1.5, p = 0.003). Multiple linear regression analyses, controlling for age, sex, education, cigarette smoking, and MMSE scores, showed that SCA3 (p = 0.021), sex (p = 0.003) and MMSE scores (p = 0.002) had significant regression coefficients. All the variables taken together were significantly associated with the SS-16 scores (p ≤ 0.001). Although MMSE scores and female sex were stronger predictors of the SS-16 scores than SCA3, subjects with SCA3 had lower scores on the SS-16, regardless of sex or MMSE scores. Additionally, MMSE scores, sex and presence of RLS were the best predictors of SS-16 scores. Overall, our results strengthen that the sense of smell is significantly reduced in patients with SCA3 and that sex, MMSE scores and RLS also influence the SS-16 scores.     

Use of parasitological culture to detect Leishmania (Leishmania) chagasi in naturally infected dogs

In Brazil, although the domestic dog is a major target for the control actions for visceral leishmaniasis, knowledge gaps of the Leishmania species present in those animals still exist in many endemic areas. The objective of this study was the use of parasitological culture as a diagnosis tool and identification of species of Leishmania and other trypanosomatids in the canine population in the city of Cuiaba/Mato Grosso. Biological samples such as blood, intact skin fragments, cutaneous ulcers, and bone marrow were collected during a cross-sectional study and cultured on biphasic medium (Novy-MacNeil-Nicolle [NNN]/Schneider's). Leishmania isolates were characterized through isoenzyme electrophoresis. Isolates were obtained from 11.2% (n=54) of the 482 animals studied considering the different anatomical sites investigated. Leishmania chagasi was confirmed in 8.3% (n=40) dogs and Trypanosoma caninum in 2.9% (n=14). The sample of intact skin presented a higher chance of isolation of L. chagasi in symptomatic dogs and bone marrow in asymptomatic dogs (p<0.05). The results presented in this study emphasize the value of culture and confirm, for the first time, the circulation of L. chagasi in the canine population in different neighborhoods of the city of Cuiaba and broaden the knowledge of the geographical distribution of T. caninum in Brazil.     

Treadmill training induces plasticity in spinal motoneurons and sciatic nerve after sensorimotor restriction during early postnatal period: new insights into the clinical approach for children with cerebral palsy

The aim of the present study was to investigate whether locomotor stimulation training could have beneficial effects on the morphometric alterations of spinal cord and sciatic nerve consequent to sensorimotor restriction (SR). Male Wistar rats were exposed to SR from postnatal day 2 (P2) to P28. Control and experimental rats underwent locomotor stimulation training in a treadmill for three weeks (from P31 to P52). The cross-sectional area (CSA) of spinal motoneurons innervating hind limb muscles was determined. Both fiber and axonal CSA of myelinated fibers were also assessed. The growth-related increase in CSA of motoneurons in the SR group was less than controls. After SR, the mean motoneuron soma size was reduced with an increase in the proportion of motoneurons with a soma size of between 0 and 800 μm(2). The changes in soma size of motoneurons were accompanied by a reduction in the mean fiber and axon CSA of sciatic nerve. The soma size of motoneurons was reestablished at the end of the training period reaching controls level. Our results suggest that SR during early postnatal life retards the growth-related increase in the cell body size of motoneurons in spinal cord and the development of sciatic nerve. Additionally, three weeks of locomotor stimulation using a treadmill seems to have a beneficial effect on motoneurons' soma size.     

Marrow stromal fibroblastic cell cultivation in vitro on decellularized bone marrow extracellular matrix

The in vitro biocompatibility of decellularized bone marrow extracellular matrix was evaluated. Following a freeze-thaw cycle, sectioned discs of fresh frozen rat metaphyseal bone were sequentially incubated in solutions of hypertonic, then hypotonic Ringer's solution, followed by deoxycholic acid, then DNAase I. The adequacy of decellularization of marrow stroma was examined by light microscopy. Marrow stromal fibroblastic cells were harvested by dispersion of rat long bone marrow, followed by concentration by discontinuous Ficoll-Paque gradient centrifugation. The fibroblastic cells were expanded by in vitro cultivation, and second passage cells were cryopreserved until needed. Cryopreserved marrow stromal cells were applied dropwise to sections of decellularized bone marrow extracellular matrix, and cultured in BJGb medium with 20% fetal bovine serum for ten days. Mature cultures were formalin fixed, decalcified, and embedded in paraffin. Light microscopy of hematoxylin and eosin stained sections showed individual spindle cells invading the upper portion of the decellularized extracellular matrix, and also a monolayer of spindle cells on the upper surfaces of exposed trabecular and cortical bone. This experiment showed that decellularized marrow extracellular matrix is a biocompatible three dimensional in vitro substrate for marrow stromal fibroblastic cells.     

Trypanosoma cruzi-Induced Activation of Functionally Distinct αβ and γδ CD4? CD8? T Cells in Individuals with Polar Forms of Chagas' Disease

CD4⁻ CD8⁻ (double-negative [DN]) T cells have recently been shown to display important immunological functions in human diseases. They express γδ or αβ T-cell receptors that recognize lipid/glycolipid antigens presented via the nonclassical major histocompatibility complex molecules of the CD1 family. We recently demonstrated that while αβ DN T cells serve primarily to express inflammatory cytokines, γδ DN T cells express mainly interleukin-10 (IL-10) in patients with cutaneous leishmaniasis. We also demonstrated a correlation between DN T cells and the expression of gamma interferon in the acute phase of Trypanosoma cruzi experimental infection. In this work, we sought to investigate whether αβ or γδ DN T cells display distinct immunoregulatory potentials in patients with polar forms of human Chagas'' disease. Our data showed that in vitro infection with T. cruzi leads to expansion of DN T cells in patients with the indeterminate and severe cardiac clinical forms of the disease. However, while αβ DN T cells primarily produce inflammatory cytokines in both forms of the disease, γδ DN T cells display a marked, significant increase in antigen-specific IL-10 expression in indeterminate patients relative to cardiac patients. Finally, higher frequencies of the IL-10-producing γδ DN T cells were correlated with improved clinical measures of cardiac function in the patients, suggesting a protective role for these cells in Chagas'' disease. Taken together, these data show distinct functional characteristics for αβ and γδ DN T cells associated with distinct morbidity rates and clinical forms in human Chagas'' disease.T-cell activation is a key event in the establishment of immune responses directed toward intracellular pathogens. Depending on the functional capacity of the activated T cells, the fate of the infection may take different paths either toward a protective or a pathogenic outcome. While it is important that a strong, activated immune response is elicited early on in the infection in order to eliminate (or control) the pathogen, the further control of this activation is necessary to reestablish homeostasis, avoiding tissue damage (17, 25).One hallmark of most parasitic infections is that the great majority of individuals are able to trigger innate immunity and elicit an activated T-cell response during the acute infection, leading to the control of the parasite and establishment of a chronic infection. Interestingly, while many individuals develop severe forms of parasitic diseases once infection progresses to the chronic phase, most patients develop relatively mild forms, allowing for a host-parasite coexistence. One such example is observed upon human infection with the protozoan parasite Trypanosoma cruzi, which leads to Chagas'' disease. As a result of thousands of years of coevolution between human host and the parasite (6), most infected individuals develop an asymptomatic, or “indeterminate” (I), form of Chagas'' disease. This form is characterized by a lack of clinical signs and symptoms and has been associated predominantly with a modulatory cellular immune response based on cytokine profiles and downregulatory molecule expression (5, 20, 48, 49, 51). Chronic patients may also develop symptomatic clinical forms, mainly with digestive or cardiac alterations. Differential geographical prevalence of Chagas'' disease clinical forms has been reported. In Brazil, 15 to 30% of Chagas'' patients display the cardiac form, which is present in 20 states, while the digestive cases, observed in about 10% of infected individuals, have been reported in four states in the central region of the country (53). The digestive form is frequently found in Chile but is practically absent in Central America (42). These geographical differences might be related, in part, to host genetics and immune responses of local human populations, but it is believed that they are also related to the genetic diversity of T. cruzi strains (11). Different strains of parasite display tropism for different tissues, and, thus, an important factor determining the clinical course of disease might be the specific pool of infecting clones and their specific tropisms (29). However, a possible role for environmental, nutritional, and immunological aspects of the host cannot be discounted. While digestive and cardiac forms present significant morbidity, the cardiac form is the one associated with highest mortality. It is caused by neuronal and cardiomyocyte damage, ultimately resulting in ventricular dilation and subsequent functional heart failure, which can lead to death (44). Cardiac patients display a T-cell-mediated inflammatory response in situ (13, 24, 41), which is responsible for the pathology; this inflammatory profile is also observed in circulating activated T cells found at high frequencies in these patients (2, 16, 19, 32). Although it is clear that a plethora of parasite and host factors influences the clinical outcome of Chagas'' disease, recent studies have suggested that activation of functionally distinct T-cell populations in T. cruzi-infected individuals may be responsible for the establishment of different clinical forms (17, 20). Thus, identifying these populations and the factors responsible for their activation will be critical for driving immune-based interventions to prevent pathology.While the great majority of T cells express either the CD4 or the CD8 molecules, which are important for stabilizing the peptide-major histocompatibility complex (MHC) complex and which favor T-cell activation, a minority population of T cells that do not express CD4 or CD8 molecules has been identified in humans (8, 10, 27, 37). These double-negative (DN) T cells have been shown to be important sources of immunoregulatory cytokines in human leishmaniasis (4), to display modulatory functions (38), but also, under different circumstances, to display cytolytic activity (10, 36). A subpopulation of DN T cells is activated through the engagement of αβ or γδ T-cell receptors (TCRs) in the recognition of nonclassical MHC molecules of the CD1 family, presenting lipid or glycolipid antigens (36). This particular lipid/glycolipid antigenic recognition, as well as the immunoregulatory potential and susceptibility to chronic stimulation of these cells, highlights the important role these cells play in parasitic infections.In our work with Bottrel et al., we determined that DN lymphocytes were the second most prevalent cell type producing gamma interferon (IFN-γ) in human cutaneous leishmaniasis and that this IFN-γ production was seen after short-term cultures with medium alone, as well as after stimulation with soluble Leishmania antigen (SLA) (9). The novel work of Antonelli et al. went on to demonstrate that DN T cells composed of two different cell populations are present in the blood of individuals infected with Leishmania braziliensis and that DN T cells expressing the αβ TCR displayed a profile consistent with activation of leishmanicidal and inflammatory activities (higher IFN-γ and tumor necrosis factor alpha [TNF-α]) while the DN subpopulation expressing γδ TCR had a modulatory potential via higher production of interleukin-10 (IL-10) (4). Interestingly, IFN-γ production has been associated with pathogenic responses in human leishmaniasis in more than one clinical form (3, 7, 22). We recently demonstrated that rats infected with the CL-Brenner clone of T. cruzi displayed a marked increase in the frequency of circulating DN T cells during the acute phase of infection (33). Taken together, these data led to the question of the role that DN T-cell subpopulations play in the clinical dichotomy of chronic human Chagas'' disease.To answer these questions, we investigated the immunoregulatory potential of DN T cells in patients with the two polar forms of Chagas'' disease: indeterminate (I) and dilated cardiac (DC). Our data demonstrated that although no quantitative differences were seen with regard to the nonstimulated frequency of DN αβ and γδ T-cell subpopulations between patients and nonchagasic individuals, in vitro infection with trypomastigote forms of T. cruzi induced a marked increase in the frequency of these cells from chagasic patients. Moreover, the expanded αβ DN T cells displayed a greater inflammatory potential from cardiac patients than from indeterminate patients. This was accompanied by a greater down-modulatory ratio of IL-10 to inflammatory cytokine frequencies by γδ DN T cells from individuals with indeterminate disease, suggesting distinct roles for these cells in modulating the response in chronic Chagas'' disease. Finally, we observed a correlation between higher frequencies of IL-10-producing γδ DN T cells and improved clinical measures of cardiac function, suggesting a protective role for these cells in human Chagas'' disease. These data indicate that functionally distinct DN T cells are present in Chagas'' disease patients and that they are associated with the resulting morbidity of the disease.     

微创全髋关节置换术前外侧肌间隙入路的解剖学研究及临床应用

目的 为在国内更好地开展前外侧肌间隙入路髋关节微创置换术,研究国人相关解剖结构,探讨手术技术并观察临床效果. 方法 解剖3具(6髋)新鲜成年尸体标本,观察国人前外侧肌间隙入路周围解剖结构.对16例患者实施前外侧肌间隙入路微创全髋关节置换术,总结临床结果 和手术操作技术. 结果 尸体解剖见手术入路为长三角形间隙,其上内角处臀中肌前缘与阔筋膜张肌后缘有部分肌纤维连接,是臀上神经下支经臀中肌进入阔筋膜张肌的关键部位,手术切口上缘不应超出此范围.临床手术切口长7～10 cm(平均8.8 cm),术中出血250～550 ml(平均350 ml).术后3～5 d下床活动.7例术中发现臀中肌前缘肌纤维部分挫裂伤,予以修剪.随访18～39个月(平均27.7个月).术后X线片显示多数假体位置良好,1例髋臼前倾角偏大,2例髋臼外展角偏大,但均无并发症和明显功能障碍.髋关节Harris评分术前为(39.1±6.7)分,术后6个月为(80.6±11.3)分,术后12个月为(88.7±9.6)分,术后24个月(11例)为(91.4±13.5)分.所有患者未发现臀中肌无力现象. 结论 前外侧肌间隙入路髋关节微创置换术具有解剖层次简单、手术创伤小、不剥离或损伤肌肉、术后康复快等优点,有实用价值并适合在体形较小的国人中推广.但术中需避免因大转子撞击敏髋臼锉修的前倾角偏大及切口远端软组织限制致髋臼外展角增加.注意准确定位皮肤切口,并使用微创技术专用手术器械.     

Effects of vertical HIV infection on the persistence of anti-HBs after a schedule of three doses of recombinant hepatitis B vaccine

Anti-HBs persistence following HBV vaccination among HIV-positive children has never been systematically studied in central Brazil. An historical cohort study was performed aiming to evaluate persistence of anti-HBs in HIV-positive children in comparison with an HIV-negative child group. Fifty-eight HIV-positive and 116 HIV-negative individuals were enrolled. Birth weight, breast-feeding duration, and the time elapsed since the last hepatitis B vaccine doses were similar between the groups. Fourteen (24%) out of 58 HIV-positive participants were anti-HBs positive and 101 (87%) out of 116 were HIV-negative (p<0.001). Among anti-HBs-positive individuals, the geometric mean titres were 118 and 298 mIU/mL, respectively to HIV-positive and HIV-negative groups (p=0.04). These results disclose a worrying picture regarding the failure of standard HBV vaccination among Brazilian HIV-infected children.     

Influence of Contact Plateaus Characteristics Formed on the Surface of Brake Friction Materials in Braking Performance through Experimental Tests

This work applies a procedure for analysis and characterization of the surface of brake friction materials, correlating them with the tribological and thermal properties achieved in different vehicle braking conditions. Experiments were performed in a vehicle under two real conditions of braking operation, simulated flat track descent and emergency braking. Characteristics of the plates formed on the surfaces of the friction materials were analyzed by scanning electron microscopy (SEM) and correlated with the performance during braking, as measured by the coefficient of friction at the interface of the friction pair and temperature. As a result, the formation of the primary and secondary plateaus in these two different braking operating conditions was observed, and the relationship between the characteristics of the plateaus formed on the surface and the surface roughness parameters and performance measurements during braking.     

In vivo influence of residual moisture on microtensile bond strengths of one-bottle adhesives

Purpose: This study evaluated the microtensile bond strengths of three dentin adhesives applied on clinically moist dentin or on dentin that was dried with air for 5 seconds. The null hypothesis to test was that the level of residual moisture does not influence bond strengths when restorations are placed in vivo.
Materials and Methods: Twenty-four premolars scheduled to be extracted for orthodontic reasons from patients between the ages of 15 and 23 years were restored with one of the following adhesive systems followed by a mini hybrid composite resin: Excite (Ivoclar/Vivadent), an ethanol-based dentin adhesive; Prime & Bond NT (Dentsply/Caulk), an acetone-based dentin adhesive; and Single Bond (3M ESPE), an ethanol and water-based dentin adhesive. After extraction, the specimens were sectioned with a slow-speed diamond saw in two perpendicular directions to obtain sticks with a cross-section of 0.7 ± 0.2 mm². The specimens were attached to a Geraldeli device and fractured using a universal testing machine at a crosshead speed of 1 mm per minute.
Results: For each dentin adhesive, there were no statistical differences between means for dry dentin versus moist dentin. Single Bond and Prime & Bond NT ranked in the same statistical subset regardless of the moisture condition of the substrate. Both Excite, dry, and Excite, moist, resulted in statistically lower bond strengths than Single Bond, moist, but similar to those of Single Bond, dry, Prime & Bond NT, moist, and Prime & Bond NT, dry.
CLINICAL SIGNIFICANCE
In this study, the level of residual moisture did not influence microtensile bond strengths. Clinically, the degree of moisture left on the dentin surface upon rinsing off the etching gel may not be as relevant as previously reported in laboratory studies.     

A functional interleukin-1 beta gene polymorphism is associated with chronic periodontitis in a sample of Brazilian individuals

BACKGROUND: Interleukin-1 beta (IL-1 beta) is a potent inflammatory mediator and an important polymorphism in the locus +3954 (C/T) of the human IL1 B gene has been shown to affect the levels of this cytokine. This functional polymorphism has been associated with the establishment of inflammatory diseases, including periodontal disease, in European, Asian and North American populations. OBJECTIVE: The aim of this study was to investigate the association between the IL1 B (+3954) gene polymorphism and the occurrence of different clinical forms of periodontitis in a sample of Brazilian individuals. METHODS: This study employed a cross-sectional design involving individuals from the State of Minas Gerais in the south-eastern region of Brazil. Genomic DNA was obtained from oral swabs of 129 individuals and amplified using the polymerase chain reaction (PCR) with specific primers flanking the locus +3954 of IL1 B. PCR products were submitted to restriction endonuclease digestion and analyzed by polyacrylamide gel electrophoresis, to distinguish alleles T and C of the IL1 B gene, allowing for the determination of the genotypes and detection of the polymorphism. RESULTS AND CONCLUSIONS: The chronic periodontitis group displayed a higher percentage of the T allele (28%) when compared to the aggressive periodontitis group (10.7%, chi(2)=5.24, p=0.02, OR=0.31, CI=0.11--0.88) and to control group (8.7%, chi(2)=7.11, p=0.007, OR=0.24, CI=0.08--0.73). Our data suggested that the polymorphism in the locus +3954 of IL1 B gene could be a risk factor for chronic periodontitis in a sample of Brazilian individuals.