Lesion of the subthalamic nucleus reverses motor deficits but not death of nigrostriatal dopaminergic neurons in a rat 6-hydroxydopamine-lesion model of Parkinson's disease

The objective of the present study was to determine whether lesion of the subthalamic nucleus (STN) promoted by N-methyl-D-aspartate (NMDA) would rescue nigrostriatal dopaminergic neurons after unilateral 6-hydroxydopamine (6-OHDA) injection into the medial forebrain bundle (MFB). Initially, 16 mg 6-OHDA (6-OHDA group) or vehicle (artificial cerebrospinal fluid - aCSF; Sham group) was infused into the right MFB of adult male Wistar rats. Fifteen days after surgery, the 6-OHDA and SHAM groups were randomly subdivided and received ipsilateral injection of either 60 mM NMDA or aCSF in the right STN. Additionally, a control group was not submitted to stereotaxic surgery. Five groups of rats were studied: 6-OHDA/NMDA, 6-OHDA/Sham, Sham/NMDA, Sham/Sham, and Control. Fourteen days after injection of 6-OHDA, rats were submitted to the rotational test induced by apomorphine (0.1 mg/kg, ip) and to the open-field test. The same tests were performed again 14 days after NMDA-induced lesion of the STN. The STN lesion reduced the contralateral turns induced by apomorphine and blocked the progression of motor impairment in the open-field test in 6-OHDA-treated rats. However, lesion of the STN did not prevent the reduction of striatal concentrations of dopamine and metabolites or the number of nigrostriatal dopaminergic neurons after 6-OHDA lesion. Therefore, STN lesion is able to reverse motor deficits after severe 6-OHDA-induced lesion of the nigrostriatal pathway, but does not protect or rescue dopaminergic neurons in the substantia nigra pars compacta.

Selective destruction of nigrostriatal dopaminergic neurons does not alter [3H]-ryanodine binding in rat striatum

Dopamine nigrostriatal neurons are important for motor control and may contain a particularly dense population of ryanodine receptors involved in the control of dopamine release. To test this hypothesis, we used a classical model of unilateral selective lesion of these neurons in rats based on 6-hydroxydopamine (6-OHDA) injection into the substantia nigra. Binding of [3H]-GBR 12935, used as a presynaptic marker since it labels specifically the dopamine uptake complex, was dramatically decreased by 83-100% in striatum homogenates after 6-OHDA lesion. On the contrary, no reduction of [3H]-ryanodine binding was observed. The present data indicate that [3H]-ryanodine binding sites present in rat striatum are not preferentially localized in dopaminergic terminals.

Neuroprotective effect of ketamine/xylazine on two rat models of Parkinson's disease

There is a great concern in the literature for the development of neuroprotectant drugs to treat Parkinson's disease. Since anesthetic drugs have hyperpolarizing properties, they can possibly act as neuroprotectants. In the present study, we have investigated the neuroprotective effect of a mixture of ketamine (85 mg/kg) and xylazine (3 mg/kg) (K/X) on the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or 6-hydroxydopamine (6-OHDA) rat models of Parkinson's disease. The bilateral infusion of MPTP (100 µg/side) or 6-OHDA (10 µg/side) into the substantia nigra pars compacta of adult male Wistar rats under thiopental anesthesia caused a modest (~67%) or severe (~91%) loss of tyrosine hydroxylase-immunostained cells, respectively. On the other hand, an apparent neuroprotective effect was observed when the rats were anesthetized with K/X, infused 5 min before surgery. This treatment caused loss of only 33% of the nigral tyrosine hydroxylase-immunostained cells due to the MPTP infusion and 51% due to the 6-OHDA infusion. This neuroprotective effect of K/X was also suggested by a less severe reduction of striatal dopamine levels in animals treated with these neurotoxins. In the working memory version of the Morris water maze task, both MPTP- and 6-OHDA-lesioned animals spent nearly 10 s longer to find the hidden platform in the groups where the neurotoxins were infused under thiopental anesthesia, compared to control animals. This amnestic effect was not observed in rats infused with the neurotoxins under K/X anesthesia. These results suggest that drugs with a pharmacological profile similar to that of K/X may be useful to delay the progression of Parkinson's disease.

Prognóstico de pacientes com tumor de Wilms unilateral no Rio de Janeiro, 1990-2000

OBJETIVO: Analisar a sobrevida e os principais fatores prognósticos entre os pacientes com tumor de Wilms unilateral. MÉTODOS: A coorte de estudo incluiu 132 casos de tumor de Wilms unilateral em menores de 15 anos de idade matriculados em serviço de oncologia pediátrica, de janeiro de 1990 a dezembro de 2000. Curvas de sobrevida foram confeccionadas utilizando-se o método de Kaplan-Meier e fatores prognósticos foram analisados pelo modelo de riscos proporcionais de Cox. RESULTADOS: A estimativa de sobrevida global em cinco anos foi 84,6%. As probabilidades de sobrevida para os estádios I, II, III e IV foram de 100%; 94,2%; 83,2% e 31,3%, respectivamente. A taxa de sobrevida para os pacientes com: histologia favorável foi de 89,4%, para aqueles com anaplasia focal 66,7 % e com anaplasia difusa 40%. Todos os pacientes com doença em estádio IV e anaplasia difusa foram a óbito (n=4). Todos os pacientes com doença em estádio I, independente da histologia, permaneceram vivos até o final do período de seguimento. CONCLUSÕES: Entre as variáveis escolhidas para o modelo final apenas o estadiamento e a histologia permaneceram associados ao elevado risco de óbito enquanto que os casos na faixa etária entre 24 e 47 meses apresentaram melhor prognóstico que os demais. Esses resultados mostram a importância do diagnóstico em fases iniciais da doença e que a histologia é fundamental para orientar a terapia adequada.

Paralisia diafragmática unilateral reversível associada a envenenamento loxoscélico sistêmico

Relata-se o caso de um paciente vítima de envenenamento loxoscélico associado a paralisia diafragmática direita reversível. O diagnóstico de envenenamento loxoscélico baseou-se nas informações prestadas pelo paciente de que havia encontrado uma aranha marrom em sua cama no dia seguinte à picada e no quadro clínico típico deste tipo de envenenamento: lesão cutânea necrótica acompanhada de erupção escarlatiniforme e comprometimento sistêmico sob a forma de insuficiência renal aguda, distúrbios da coagulação sangüínea, hemólise intravascular e hemoglobinúria. Estas alterações regrediram completamente com o tratamento conservador. O diagnóstico da paralisia diafragmática baseou-se na elevação da hemicúpula diafragmática direita na radiografia de tórax em inspiração forçada e em sua completa imobilidade no exame radioscópico. A paralisia frênica não existia na radiografia realizada previamente ao acidente e desapareceu completamente trinta dias após o mesmo, o que permitiu associá-la à toxocidade do veneno loxoscélico ou a outras manifestações sistêmicas produzidas por ele.

Cerebral mass lesion due to cytomegalovirus in a patient with AIDS: case report and literature review

Cytomegalovirus (CMV) disease in acquired immunodeficiency syndrome (AIDS) patients most commonly presents as chorioretinitis and gastro-intestinal infection. Neurological involvement due to CMV may cause several clinical presentations: polyradiculitis, myelitis, encephalitis, ventriculo-encephalitis, and mononeuritis multiplex. Rarely, cerebral mass lesion is described. We report a 39 year-old woman with AIDS and previous cerebral toxoplasmosis. She presented with fever, seizures, and vulval ulcers. Her chest X-ray showed multiple lung nodules, and a large frontal lobe lesion was seen in a brain computed tomography scan. She underwent a brain biopsy through a frontal craniotomy, but her condition deteriorated and she died in the first postoperative day. Histopathological studies and immunohistochemistry disclosed CMV disease, and there was no evidence of cerebral toxoplasmosis, bacterial, mycobacterial or fungal infection. CMV disease should be considered in the differential diagnosis of cerebral mass lesion in AIDS patients. High suspicion index, timely diagnostic procedures (surgical or minimally invasive), and proper utilization of prophylactic and therapeutic medication could improve outcome of these patients.

Assessment of Thromboembolism After the Cox-Maze Procedure for Chronic Atrial Fibrillation Secondary to Mitral Valve Lesion

OBJECTIVE: To assess the occurrence of late thromboembolism after surgical repair of chronic atrial fibrillation (AF) simultaneously with repair of mitral valve using the Cox-Maze procedure. METHODS: 69 patients underwent Cox 3 procedure, with no cryoablation simultaneously with mitral valvuloplasty or prosthesis. Mean age was 49.9±13.2 years. Mean follow-up was of 31.7±19 months. Types of lesion were as follows: 33 (48%) stenoses, 23 (33%) insufficiencies, and 13 (19%) double lesions. Procedures were: 64 (93%) valvuloplasties, 3 (4%) biological and 2 (3%) mechanical prosthesis placement. There were 9 (13%) patients with previous systemic embolism and 2 (3%) had left atrial thrombi. RESULTS: Early mortality was 7% and late 1%. 2 patients (3%) were reoperated for mitral placement. At last evaluation, 10 patients (15%), were in AF. The remaining 59 (85%) were either in sinus / atrial rythm (74%) or under pacing (12%). There were no occurrence of early or late, systemic or pulmonary embolism. Permanent anticoagulation was employed in 16 cases, 10 in regular rythm and 6 in AF. The remaining 47 (75%), 2 in AF and 45 in regular rythm, did not receive anticoagulants. CONCLUSIONS: These results are in accordance with others series, where the occurrence of embolism was rare after maze procedure. Permanent systemic anticoagulation seems to be unnecessary in those cases.

Polymerase chain reaction with lesion scrapping for the diagnosis of human American tegumentary leishmaniasis

The objective of this work was to compare the polymerase chain reaction (PCR) using lesion scrapping with other conventional techniques for the diagnosis of the American tegumentary leishmaniasis (ATL). For this, patients with cutaneous lesions suspected to be ATL were studied. The DNA was amplified with the MP1L/MP3H primers. From the 156 studied patients, 79 (50.6%) presented positive parasite direct search (PD), 81 (51.9%) had positive Montenegro skin test (MST), and 90 (57.7%) presented PD and/or MST positive. The PCR was positive in all of the positive-PD patients (100% sensitivity), in 91.1% of the positive PD and/or MST patients, and in 27.3% of the patients that presented negative PD and positive MST. The PCR positivity was similar to the PD (P = 0.2482) and inferior to the MST (P = 0.0455), and to the PD/MST association (P = 0.0133). The high PCR sensitivity, and positivity in those cases where the PD was negative, highlights the importance of this technique as an auxiliary tool for the diagnosis of ATL.

Interferon-gamma is required for the late but not early control of Leishmania amazonensis infection in C57Bl/6 mice

The critical role of interferon-gamma (IFN-g) in the resistance of C57Bl/6 mice to Leishmania major is widely established but its role in the relative resistance of these animals to L. amazonensis infection is still not clear. In this work we use C57Bl/6 mice congenitally deficient in the IFN-g gene (IFN-g KO) to address this issue. We found that IFN-g KO mice were as resistant as their wild-type (WT) counterparts at least during the first two months of infection. Afterwards, whereas WT mice maintained lesion growth under control, IFN-g KO mice developed devastating lesions. At day 97 of infection, their lesions were 9-fold larger than WT controls, concomitant with an increased parasite burden. At this stage, lesion-draining cells from IFN-g KO mice had impaired capacity to produce interleukin-12 (IL-12) and tumour necrosis factor-a in response to parasite antigens whereas IL-4 was slightly increased in comparison to infected WT mice. Together, these results show that IFN-g is not critical for the initial control of L. amazonensis infection in C57Bl/6 mice, but is essencial for the developmente of a protective Th1 type immune response in the later stages.

Unilateral pulmonary veins atresia: evaluation by computed tomography

Unilateral pulmonary vein atresia is a rare congenital condition. In addition to cardiac malformations or pulmonary hypertension, patients may present with recurrent pulmonary infections or hemoptysis in childhood or adolescence. The authors report a case where the typical findings of such condition were observed at computed tomography in an adult patient.

Tireoidectomia unilateral no carcinoma diferenciado da tireóide de baixo risco: uma cirurgia inadequada

OBJETIVO: Caracterizar os doentes operados de carcinoma diferenciado da tireóide no Hospital Universitário Clementino Fraga Filho (HUCFF); avaliar a divisão destes doentes em alto e baixo riscos e a validade da cirurgia conservadora nos pacientes com carcinoma diferenciado de baixo risco. MÉTODO: Foram analisados 169 pacientes operados no HUCFF por carcinoma diferenciado da tireóide. Cento e cinqüenta e dois (90%) eram mulheres e 17 (10%) homens. A idade variou entre 13 e 85 anos com mediana de 39 anos. Cento e onze tumores (65,7%) eram papilíferos e 58 (34,3%) foliculares. RESULTADOS: Vinte e um por cento apresentaram metástases linfonodais cervicais quando vistos pela primeira vez e 1,7% metástases a distância. Houve 75 cirurgias unilaterais (lobectomia subtotal ou total) e 94 bilaterais (tireoidectomia subtotal, lobectomia total + lobectomia subtotal ou tireoidectomia total). 127 casos (75,2%) foram considerados pacientes de baixo risco e 42 casos (24,8%) de alto risco. O seguimento pós-operatório foi conseguido em 155 pacientes: 116 entre os de baixo risco, com seguimento médio de 8,4 anos (extremos: um ano a 21 anos) e 39 entre os de alto risco (seguimento médio cinco anos, extremos um ano e 17 anos). Foram encontrados 13 recidivas tumorais (8,3%) e cinco óbitos pelo tumor (3,2%) em toda a série: 10 (8,6% recidivas e nenhum óbito nos pacientes de baixo risco e três recidivas (7,5%) e cinco óbitos (12,5%) nos de alto risco. Nos pacientes de baixo risco submetidos à tireoidectomia parcial houve 7,5% de recidivas e nos pacientes com tireoidectomia total a ocorrência de recidivas foi de 10%. Não houve óbitos pelo tumor em nenhum dos grupos. CONCLUSÕES: Os pacientes com tumores de baixo risco apresentam evolução mais favorável: número igual de recidivas (relativamente aos tumores de alto risco), porém menos graves, e nenhum faleceu pelo tumor. Nos pacientes de baixo risco a cirurgia unilateral mostrou resultados idênticos aos da bilateral.

Experimental osteoarthritis in rabbits: lesion progression

The aim of this study was to evaluate the progression of lesions in different stages of osteoarthritis (OA) experimental by radiography (RX), computed tomography (CT), macroscopic and histopathology, linking these different diagnostic methods, helped to provide information that helps the best time for the therapeutic approach. Four experimental periods were delineated at 3, 6, 9 and 12 weeks after induction of OA, known as PI, PII, PIII and PIV, respectively, each with six animals. We evaluated the five compartments of the femorotibial joint: medial femoral condyle (MFC), lateral femoral condyle (LFC), medial tibial plateau (MTP), lateral tibial plateau (LTP) and femoral trochlea (FT). Therefore we established an index by compartment (IC) and by adding such an index was estimated joint femorotibial (IFT). It was observed that the CFM was the compartment with the highest IC also differed significantly (p<0.05) from other compartments. Compartments showed no significant difference (p>0.05) between the PI and PII, however contrary fact occurred between the PII and PIII (p<0.05), PIII and PIV (p<0.01) and between PI and PIV (p<0.001). Similarly the IFT, showed a significant difference in the animals of PIV compared to PI (p<0.001), PII (p<0.001) and PIII (p<0.01), and there was no statistical difference (p> 0.05) between the PI and PII. In the variation of the average interval between periods, there was a higher value between the PIII PIV and for the other intervals of time periods (PI, PII, and PIII-PII). However, these intervals showed no statistically significant difference (p>0.05). Through the RX, CT, macroscopic and histopathological findings, we found similar patterns among individuals within the same period demonstrating a gradual progression of the disease. These results show that between 3 and 6 weeks progression of the lesion is slower and probably also can be reversed in comparison to other ranges where proved further progression between 9 and 12 weeks after induction of trauma OA. These results may provide a better therapeutic approach aimed at reversing the lesions in early stages of OA. We conclude that the interconnection of the four diagnostic methods individually classified into scores, which were unified in both indices in the evaluation by the femorotibial joint compartment and may represent a diagnostic condition closer to the true condition of the injury and its progression.

Red eyes in the necropsy floor: twenty cases of hyphema in dogs and cats

Hyphema (hemorrhage within the anterior chamber of the eye) can be caused by several mechanisms and can easily be detected in routine ophthalmic or necroscopic examination as discolored red eye(s). The purpose of this study is to report the cause of hyphema diagnosed as a postmortem finding in dogs and cats. Twenty cases, 14 dogs and six cats of several ages and breeds and of both sexes were included in the study. Hyphema presented as a unilateral (14 cases out of 20) or bilateral (6/20) disorder in dogs and cats and extension of hemorrhage varied from minimal to diffuse. Hyphema was secondary to systemic disease (15/20) or occurred as a primary ocular lesion (5/20) in four dogs and one cat. Primary hyphema was always unilateral. In four of these cases, the cause of hyphema was trauma and remaining case was caused by phacoclastic uveitis in a dog with bilateral hypermature cataract. Various causes of bleeding disorders were found related to secondary hyphema: in decreasing order of frequency, they included vasculitis (8/15), systemic hypertension (5/15), and acquired coagulopathies (2/15). Vasculitis due to feline infectious peritonitis accounted for half of the cases (n=3) of systemic hyphema in cats. The various pathological aspects and pathogenesis of hyphema in dogs and cats are described and discussed.