Identification of the myodural bridge in a venomous snake, the gloydius shedaoensis: what is the functional significance? / Identificación del puente miodural en una serpiente venenosa, gloydius shedaoensis: ¿cuál es el significado funcional?

SUMMARY: Myodural bridges (MDB) are anatomical connections between the suboccipital muscles and the cervical dura mater which pass through both the atlanto-occipital and the atlanto-axial interspaces in mammals. In our previous studies, we found that the MDB exists in seven terrestrial mammal species, two marine mammal species, two reptilian species, and one bird species. A recent study suggested that given the "ubiquity" of myodural bridges in terrestrial vertebrates, the MDB may also exist in snakes. Specifically, we focused on the Gloydius shedaoensis, a species of Agkistrodon (pit viper snake) that is only found on Shedao Island, which is in the southeastern sea of Dalian City in China. Six head and neck cadaveric specimens of Gloydius shedaoensis were examined. Three specimens were used for anatomical dissection and the remaining three cadaveric specimens were utilized for histological analysis. The present study confirmed the existence of the MDB in the Gloydius shedaoensis. The snake's spinalis muscles originated from the posterior edge of the supraoccipital bones and the dorsal facet of the exocciput, and then extended on both sides of the spinous processes of the spine, merging with the semispinalis muscles. On the ventral aspect of this muscular complex, it gave off fibers of the MDB. These MDB fibers twisted around the posterior margin of the exocciput and then passed through the atlanto-occipital interspace, finally terminating on the dura mater. We observed that the MDB also existed in all of the snakes' intervertebral joints. These same histological findings were also observed in the Gloydius brevicaudus, which was used as a control specimen for the Gloydius shedaoensis. In snakes the spinal canal is longer than that observed in most other animals. Considering the unique locomotive style of snakes, our findings contribute to support the hypothesis that the MDB could modulate cerebrospinal fluid (CSF) pulsations.

RESUMEN: Los puentes miodurales (MDB) son conexiones anatómicas entre los músculos suboccipitales y la duramadre cervical que pasan a través de los espacios intermedios atlanto-occipital y atlanto-axial en los mamíferos. En nuestros estudios anteriores, encontramos que el MDB existe en siete especies de mamíferos terrestres, dos especies de mamíferos marinos, dos especies de reptiles y una especie de ave. Un estudio reciente sugirió que dada la "ubicuidad" de los puentes miodurales en los vertebrados terrestres, el MDB también puede existir en las serpientes. Específicamente, nos enfocamos en Gloydius shedaoensis, una especie de Agkistrodon (serpiente víbora) que solo se encuentra en la isla Shedao, en el mar sureste de la ciudad de Dalian en China. Se examinaron seis especímenes cadavéricos de cabeza y cuello de Gloydius shedaoensis. Se utilizaron tres especímenes para la disección anatómica y los tres especímenes cadavéricos restantes se utilizaron para el análisis histológico. El presente estudio confirmó la existencia del MDB en Gloydius shedaoensis. Los músculos espinosos de la serpiente se originaron en el margen posterior de los huesos supraoccipital y la cara dorsal del exoccipucio, y luego se extendieron a ambos lados de los procesos espinosas de la columna vertebral, fusionándose con los músculos semiespinosos. En la cara ventral de este complejo muscular se desprendían fibras del MDB. Estas fibras MDB se ubican alrededor del margen posterior del exoccipucio y luego atraviesan el interespacio atlanto-occipital, terminando finalmente en la duramadre. Observamos que el MDB también existía en todas las articulaciones intervertebrales de las serpientes. Estos mismos hallazgos histológicos también se observaron en Gloydius brevicaudus, que se utilizó como muestra de control para Gloydius shedaoensis. En las serpientes, el canal espinal es más largo que el observado en la mayoría de los otros animales. Teniendo en cuenta el estilo único locomotor de las serpientes, nuestros hallazgos contribuyen a respaldar la hipótesis de que el MDB podría modular las pulsaciones del líquido cerebroespinal.

MASP-2 saturation curve in cerebrospinal fluid indicates local synthesis and its equilibrium with soluble and associated forms / La curva de saturación de MASP-2 en líquido cefalorraquídeo indica síntesis local y su equilibrio con formas solubles y asociadas

Introduction: MASP-2 is a mannose blinding lectin associate to serine protease in cerebrospinal fluid and its dynamics through the blood brain barrier is unknown. Objective: To describe MASP-2 diffusion pattern from blood to cerebrospinal fluid. Methods: A transversal observational prospective study was performed 56 control samples of cerebrospinal fluid and serum were employed. ELISA measured MASP-2. Two groups were made: control patients without organic brain disease with normal cerebrospinal fluid and normal barrier function and patients without inflammatory diseases with a blood cerebrospinal fluid barrier dysfunction. Results: MASP-2 concentration in cerebrospinal fluid increase with augment the Q Albumin. QMASP-2 vs. Q Albumin saturation curve indicates that MASP-2 is interacting with other molecules in the subarachnoid environment. The higher inter-individual variation of cerebrospinal fluid MASP-2 of the control compared to the serum MASP-2 indicates that MASP-2 is a protein derived from blood. Conclusions: MASP-2 in CSF is predominantly blood-derived. The saturation curve demonstrates that MASP-2 interacts with the starters of the lectin pathway like mannose binding lectin, ficolins and collectin LK(AU)

Introducción: MASP2 es una proteína de unión a manosa asociada a una proteasa de serina encontrada en la periferia, pero puede pasar a líquido cefalorraquídeo. Sin embargo, su dinámica a través de la barrera sangre-líquido cefalorraquídeo es aún desconocida. Objetivo: Describir la difusión del MASP-2 desde la sangre al líquido cefalorraquídeo. Métodos: Se realiza estudio observacional prospectivo de corte transversal donde se emplearon 56 muestras de suero y líquido cefalorraquídeo. Fue seleccionado un grupo control con pacientes sin enfermedad orgánica del cerebro, con líquido cefalorraquídeo y función de barrera normal y otro grupo de pacientes sin enfermedades inflamatorias del cerebro con disfunción de barrera sangre-líquido cefalorraquídeo. Resultados: La concentración de MASP-2 en líquido cefalorraquídeo aumentó con el incremento de la Q Albúmina. La curva de saturación de Q MASP-2 contra la Q Albúmina indicó que el MASP-2 se encuentra interactuando con otras moléculas en el espacio subaracnoideo. El aumento del coeficiente de variación individual de MASP-2 en líquido cefalorraquídeo de los controles comparado con el MASP-2 en suero indicó que el MASP-2 es una proteína derivada de la sangre. Conclusiones: La producción de MASP-2 en líquido cefalorraquídeo es predominantemente derivada de la sangre. La curva de saturación demostró que el MASP-2 interactúa con los iniciadores de la vía de las lectinas como lectina unida a manosa, las ficolinas y la colectina LK(AU)

Kinetics-like equation for cerebrospinal fluid-blood diffusion models

Introduction: The diffusion of proteins from the blood to the cerebrospinal fluid is influenced by its molecular weight and by the intrinsic properties and biological properties of the protein. Methods: Paired samples of serum and cerebrospinal fluid were taken from normal subjects to quantify albumin and proteins of the lectin pathway of the complement system. The distribution of these with regard to the value of QAlbúmin = (Albumin in serum / albumin in cerebrospinal fluid) was evaluated because this protein is used as a marker of the passage of the barrier. Results: It was observed that some of these describe a saturation pattern which resembles the curves that describe the Michaelis-Menten reaction of enzymatic activity. This led to the consideration of two constants that will help to characterize the behavior of these proteins by spreading to the cerebrospinal fluid: the maximum Q of the protein, which is the maximum proportion found empirically between the concentrations in blood and cerebrospinal fluid and the value Kcdw which is the value of the average diffusion speed of Q albumin when the semi-maximal value of the Q of the protein under study is obtained. Conclusions: Empirically obtained constants will help the characterization and differentiation of the diffusion of these new proteins as they pass from the blood to the cerebrospinal fluid(AU)

Lectin pathway components and its transfer from blood to cerebrospinal fluid

Introduction: Defining mechanisms governing the diffusion from blood to cerebrospinal fluid is central to understanding immune function in the central nervous system. Objective: To describe the dynamics of diffusion of the lectin pathway components from blood to cerebrospinal fluid. Methods: It was organized the information available in PubMed database and of papers from journals, and abstract books from international congresses belongs mainly to Cuban authors all about the lectin pathway of complement including manan-binding lectin (MBL) and ficolins complexed with the MBL-associated serine proteases (MASP2), and of other components like MASP3, Map44 as regulatory components and the different starters like MBL, ficolins and CLLK. Results: All the lectin pathways component are blood derived proteins but at the same time it could be synthesized intrathecally. Most of the protein can be transferred from blood to cerebrospinal fluid in different aggregation forms and some of them can be described as a consuming curve. The control mechanism of regulation the lectin pathway can be followed by molecules as MASP3 and Map44. Conclusions: The under- constructed lectin pathway of the complement system required not only the available information in different journals. It had to be completed by reviewing the congress abstract book and congress website of the last years(AU)

Método de aglutinación en látex para el diagnóstico rápido del síndrome de Guillain-Barré / Latex agglutination method for fast Guillain-Barré syndromes diagnosis

El síndrome de Guillain-Barré es una polirradiculoneuropatía aguda, en la cual está involucrado un componente autoinmunitario, posterior a un proceso infeccioso en pacientes no vacunados o vacunados. A partir de la aparición del virus del dengue y del Zika en el continente americano es de esperar que exista una mayor probabilidad de encontrar pacientes con este síndrome post-infeccioso. Por tanto, poder contar con un método diagnóstico rápido pudiera ser de utilidad en los centros de asistencia que reciben casos de urgencias. Se procede a modificar un método para cuantificar albuminuria por aglutinación con partículas de látex sensibilizados, para la detección de este analito en el líquido cefalorraquídeo de aquellos pacientes con sospecha de esta enfermedad. Se comprueba que el método puede ser utilizado como método de diagnóstico rápido del síndrome de Guillain-Barré(AU)

Guillain-Barré Syndrome is an acute poliradiculoneuropathy with an autoimmune component, subsequent to an infectious process in vaccinated or non-vaccinated patients. From the spreading of dengue and Zika infections in the American continent it is expected a greater probability of finding patients with this post-infectious syndrome. Therefore, a rapid diagnostic test could be useful in emergency assistance centers. A quantitative latex agglutination test to detect albuminuria was modified to be used in cerebrospinal fluid of patients with presumptive diagnosis of this disease. It has been proved that the developed test can be used for diagnostic rapid of Guillain-Barré syndrome(AU)

Categorías de riesgo de meningitis bacteriana y tratamiento con antibióticos en neonatos con pleocitosis del líquido cefalorraquídeo / Categories of bacterial meningitis risk and antibiotic treatment for neonates with cerebrospinal fluid pleocytosis

Introducción: recientemente se desarrolló y validó el Modelo de Predicción de Meningitis Bacteriana Neonatal, lo cual provee de una herramienta efectiva en la toma de decisiones médicas para la indicación de tratamiento antibiótico ante un neonato con pleocitosis del líquido cefalorraquídeo. Objetivo: conocer cómo se procedió retrospectivamente con la indicación de tratamiento antibiótico en neonatos con pleocitosis del líquido cefalorraquídeo, antes de desarrollar el modelo mencionado, y fortalecer y fundamentar una estrategia del tratamiento antibiótico, basados en nuestro Modelo de Predicción de Meningitis Bacteriana Neonatal, ante un neonato con pleocitosis del líquido cefalorraquídeo. Métodos: estudio retrospectivo y aplicado, que incluyó 290 neonatos evaluados por probable infección, 44 con meningitis bacteriana y 246 con meningitis aséptica, ingresados en el Servicio de Neonatología del Hospital Pediátrico Juan Manuel Márquez, entre febrero/1992 y diciembre/2009. Se verificó la efectividad del Modelo de Predicción de Meningitis Bacteriana Neonatal, lo que permitió clasificar los pacientes en alto o bajo riesgo de meningitis bacteriana. Se determinó retrospectivamente la indicación y los motivos de tratamiento antibiótico ante un neonato con pleocitosis del líquido cefalorraquídeo, así como análisis de asociación para distintas circunstancias clínicas, entre ellas, la clasificación de riesgo de infección bacteriana severa. Resultados: se precisó que el Modelo de Predicción de Meningitis Bacteriana Neonatal tuvo una sensibilidad y valor predictivo negativo de 100 por ciento para meningitis bacteriana

Introduction: recently, the neonatal bacterial meningitis predicting model was developed and validated, which provides an effective tool in medical decision-making to prescribe antibiotic treatment to neonates with cerebrospinal fluid pleocytosis. Objective: to find out retrospectively the procedure to indicate the antibiotic treatment for neonates with cerebrospinal fluid pleocytosis prior to the development of the stated model, and to strengthen and substantiate an antibiotic treatment strategy, based on our neonatal bacterial meningitis prediction model of a newborn with cerebrospinal fluid pleocytosis. Methods: retrospective and implemented study of 290 neonates with probable infection; 44 had bacterial meningitis and 246 aseptic meningitis. They were all admitted to the neonatology service of Juan Manuel Marquez pediatric hospital from February 1992 to December 2009. The effectiveness of the neonatal bacterial meningitis prediction model was verified, which allowed classifying the patients into high or low bacterial meningitis risk. The indication and the reasons for antibiotic treatment of a neonate with cerebrospinal fluid pleocytosis were retrospectively determined, as well as the analysis of the association of different clinical circumstances such as the classification of severe bacterial infection risk was made. Results: the neonatal bacterial meningitis prediction model showed negative sensitivity and predictive value of 100 percent for the bacterial meningitis

Focal Anterior Displacement of the Thoracic Spinal Cord without Evidence of Spinal Cord Herniation or an Intradural Mass

OBJECTIVE: We report magnetic resonance imaging (MRI) findings on focal anterior displacement of the thoracic spinal cord in asymptomatic patients without a spinal cord herniation or intradural mass. MATERIALS AND METHODS: We identified 12 patients (male:female = 6:6; mean age, 51.7; range, 15-83 years) between 2007 and 2011, with focal anterior displacement of the spinal cord and without evidence of an intradural mass or spinal cord herniation. Two radiologists retrospectively reviewed the MRI findings in consensus. RESULTS: An asymmetric spinal cord deformity with a focal dented appearance was seen on the posterior surface of the spinal cord in all patients, and it involved a length of 1 or 2 vertebral segments in the upper thoracic spine (thoracic vertebrae 1-6). Moreover, a focal widening of the posterior subarachnoid space was also observed in all cases. None of the patients had myelopathy symptoms, and they showed no focal T2-hyperintensity in the spinal cord with the exception of one patient. In addition, cerebrospinal fluid (CSF) flow artifacts were seen in the posterior subarachnoid space of the affected spinal cord level. Computed tomography myelography revealed preserved CSF flow in the two available patients. CONCLUSION: Focal anterior spinal cord indentation can be found in the upper thoracic level of asymptomatic patients without a spinal cord herniation or intradural mass.

Neuroendoscopic surgery in children: an analysis of 200 consecutive procedures / Neuroendoscopia em crianças: uma análise de 200 procedimentos consecutivos

Neuroendoscopic surgery in children has particular features and is associated with different success rates (SR). The aim of this study was to identify putative factors that could influence the outcome in pediatric patients.

Clinical data of 177 patients under 18 years of age submitted to 200 consecutive neuroendoscopic procedures from January 2000 to January 2010 were reviewed. The overall success rate was 77%. Out of the patients with successful outcomes, 46% were under six months, 68% were between six months and one year of age, and 85% older than one year. Neuroendoscopic techniques provide very good results for a wide number of indications in children. Tumor-related cerebrospinal fluid (CSF) circulation problems and aqueductal stenosis seem to be particularly well suited to neuroendoscopic treatment regardless of the patient's age. Patients' age and etiology of hydrocephalus were associated with a different outcome. In all cases, surgical experience is extremely important to reduce complications. .

A cirurgia neuroendoscópica em crianças apresenta particularidades e está associada a diferentes taxas de sucesso (TS). O objetivo deste estudo consistiu em identificar fatores que pudessem influir no resultado do tratamento em pacientes pediátricos. Dados clínicos de 177 pacientes com idade inferior a 18 anos submetidos a 200 procedimentos neuroendoscópicos consecutivos entre janeiro de 2000 e janeiro de 2010 foram revisados. A taxa de sucesso global foi de 77%. Os pacientes com idade inferior a seis meses apresentaram taxa de sucesso de 46%; pacientes entre seis meses e um ano de vida obtiveram êxito em 68% dos casos; dentre os maiores de um ano, 85% dos procedimentos foram bem-sucedidos. Técnicas neuroendoscópicas proporcionam muito bons resultados para uma grande variedade de indicações em crianças. Independentemente da faixa etária, o tratamento endoscópico apresenta-se particularmente adequado para problemas da circulação liquórica relacionados a tumores e à estenose aquedutal. A faixa etária dos pacientes e a etiologia da hidrocefalia estão associadas a diferentes resultados. Em todos os casos, experiência neurocirúrgica é extremamente importante para a redução das complicações. .

Angiogenic potential of the cerebrospinal fluid (CSF) of patients with high-grade gliomas measured with the chick embryo chorioallantoic membrane assay (CAM)

High-grade gliomas are highly vascularized tumors. Neo-angiogenesis plays a key role in tumor growth and resistance to therapy. A cerebrospinal fluid (CSF) sample could be a useful way to obtain pro-angiogenic predictive or prognostic markers at different stages of the disease. As a first step we looked for pro-angiogenic activity in the CSF of patients with high-grade gliomas. We performed the chicken embryo chorio-allantoic membrane (CAM) assay to study the angiogenic potential of the cerebrospinal fluid (CSF), obtained either by lumbar puncture (LP) or craniotomy from six patients with high-grade brain tumors (three glioblastoma (WHO grade IV), one anaplastic oligodendroglioma (WHO grade III), two anaplastic ganglioglioma (WHO grade III)), and four healthy controls. Significantly increased neo-angiogenesis was observed on the surface of the growing CAM in the 6 patients with high-grade gliomas compared to controls (3.69 ± 1.23 versus 2.16 ± 0.97 capillaries per area (mean ± SD), p<0.005). There was no statistical difference related to the hystological grade of the tumor (WHO grade III or IV), previous treatment (radio-chemotherapy plus temozolomide, temozolomide alone or no treatment), or the site of CSF sample (surgery or lumbar puncture). Our results suggest a pro-angiogenic potential in the CSF of patients with high-grade gliomas.

Incidencia del virus herpes simplex en pacientes con infecciones agudas del sistema nervioso central / Incidence of herpes simplex virus infection in patients with acute central nervous system infections

Los Virus Herpes Simple son responsables de una variedad de infecciones a nivel de mucosas bucal y genital, son neurotrópicos, capaces de alojarse en células nerviosas y permanecer latentes con subsecuentes reactivaciones, en algunos casos pueden provocar meningitis y encefalitis. tienen una morbilidad significativa y una mortalidad elevada. El presente estudio tiene como objetivo determinar la incidencia de VHS en la etiología de los síndromes agudos del SNC mediante la detección en suero y LCR de anticuerpos específicos. Se estudiaron 93 muestras pareadas de pacientes con afecciones neurológicas que mostraron resultados negativos en el estudio bacteriológico de LCR y cuya relación Alb-LCR/Alb-suero fue <0,0075. Los anticuerpos fueron detectados por el método de inmunoensayo enzimático Elisa: Enzygnost® anti virus VHS/IgM-IgG (Behring, 1994), donde 1,2% (1/93) de las muestras de suero resultaron positivas para IgM; 89,24% (83/93)de los sueros resultaron positivos para IgG; y 27,39% (20/93) de las muestras de LCR presentaron anti-IgG positivo. La presencia de IgG en LCR sugiere la producción intratecal de estos anticuerpos en el SNC, lo que muestra una participación importante de este agente viral en las infecciones y enfermedades asociadas al SNC

Herpes simplex viruses are agents responsible for a variety of infections on buccal and genital mucosa; they are neurotropic, capable of lodging in the nerve cells and remaining latent with subsequent reactivations; in some cases, they can provoke meningitis and encephalitis; and they have a significant morbidity and are associated with a high mortality. The present project aims to determine HSV’s effect on the etiology of acute central nervous system (CNS) syndromes using the detection of specific antibodies in serum and cerebrospinal fluid. The 93 paired samples from patients with neurological affectations studied demonstrated negative results in the LCR bacteriological study and their Alb-LCR/Alb-serum relation was < 0.0075. Antibodies were detected by the enzymatic immunoassay ELISA method, where 1.2% (1/93) of the serum samples turned out positive for IgM; 89.24% (83/93) of the serum samples resulted positive for IgG; and 27.39% (20/93) of LCR samples were positive for anti-IgG. IgG presence in LCR suggested the intrathecal production of these antibodies inside the CNS, which demonstrates a significant participation by this viral agent in infections and diseases associated with the CNS

Evaluation of electrophoretic profile and albumin quota in the cerebrospinal fluid of dogs with distemper showing or not neurvous signs

The electrophoretic profile of cerebrospinal fluid proteins and albumin quota was studied in healthy dogs and dogs with distemper in either nervous or non-nervous phases. Cerebrospinal fluid (CSF) samples from 30 dogs were collected by puncture of the cisterna magna. The total protein content, the albumin quota, and the electrophoretic fraction of CSF proteins in agarose gel plates were evaluated. Results were similar in healthy dogs and dogs with distemper and no nervous signs, but were significantly increased in the group of dogs with distemper showing nervous signs. The study of CSF protein profile proved useful and contributed significantly on the detection of central nervous system disorders and damages to the blood-brain barrier during the nervous phase of distemper.

Estudaram-se o perfil eletroforético das proteínas liquóricas e a cota de albumina em cães sem e com cinomose na fase neurológica e não-neurológica. A punção da cisterna magna para a obtenção de amostras de liquor realizou-se em 30 cães. Analisaram-se teores de proteínas totais, cota de albumina e fracionamento eletroforético das proteínas liquóricas em gel de agarose. Os resultados foram semelhantes nos cães normais e nos cães com cinomose sem sinais neurológicos e significativamente elevados no grupo de cães com cinomose apresentando sinais neurológicos. O estudo do quadro protéico do líquido cérebroespinhal foi útil e contribuiu significativamente na detecção de lesões ao sistema nervoso central e de danos à barreira hematoencefálica durante a fase neurológica da cinomose.

Localização da lesão e achados do líquido cefalorraqueano na meningite tuberculosa: diferenças nos compartimentos lombar, cisternal e ventricular / Location of the lesion and the cerebrospinal fluid findings in tuberculous meningitis: differences in the lumbar, cisternal and ventricular compartiments

A tuberculose permanece como uma das doenças infecciosas mais freqüentes no mundo. No presente estudo, relatamos um caso de meningite tuberculosa, que evoluiu com bloqueio do fluxo do líquido cefalorraqueano (LCR), causando dificuldade diagnóstica. Discute-se a importância da localização da lesão e sua influência no exame do LCR como apoio ao diagnóstico da meningite tuberculosa. No caso relatado, a pesquisa do bacilo álcool-ácido resistente foi positiva no LCR cisternal e negativa no LCR lombar e ventricular, demonstrando que a maior acurácia do teste esteve relacionada a maior proximidade da lesão inflamatória.

Estudio del flujo del líquido cefalorraquídeo (LCR) con cine resonancia magnética (CINE RM) / Cerebrospinal fluid flow Study (LCR) with Cine Magnetic Resonance Imaging (CINE RM)

En el presente trabajo se analiza la experiencia preliminar en la Clínica Las Condes, referida a 69 pacientes. En su indicación predominó la evaluación del tipo de circulación de LCR en quistes aracnoidales, hidrocefalia y malformación de Chiari I con o sin siringomielia. Fue extremadamente útil en los quistes aracnoidales, siendo no comunicantes diez y comunicantes cuatro. En hidrocefalia, ayudó al diagnóstico gracias al flujo hiperdinámico de los ventrículos laterales, producido en esta patología. En la malformación de Chiari I ilustró en forma elegante el efecto pistón, su correción por la descompresiva occipitocervical y la duroplastía de expansión con aponeurosis de pericráneo. Demostró una gran utilidad en el control de funcionalidad de las tercerventrículocisternostomías.

Biodegradable Polymer Releasing Antibiotic Developed for Drainage Catheter of Cerebrospinal Fluid:In Vitro Results

The authors developed a biodegradable polymer that releases an antibiotic (nalidixic acid) slowly and continuously, for prevention of catheter-induced infection during drainage of cerebrospinal fluid. We investigated the in vitro antibiotic releasing characteristics and bacterial killing effects of the new polymer against E. coli. The novel fluoroquinolone polymer was prepared using diisopropylcarbodiimide, poly (e-capro-lactone) diol, and nalidixic acid. FT-IR, mass spectrometry, and elemental analysis proved that the novel antibacterial polymer was prepared successfully without any side products. Negative MS showed that the released drug has a similar molecular weight (M.W.=232, 350) to pure drug (M.W.=232). In high pressure liquid chromatography, the released drug and drug-oligomer showed similar retention times (about 4.5-5 min) in comparison to pure drug (4.5 min). The released nalidixic acid and nalidixic acid derivatives have antibacterial characteristics against E. Coli, Staphylococcus aureus, and Salmonella typhi, of more than 3 months duration. This study suggests the possibility of applying this new polymer to manufacture drainage catheters that resist catheter-induced infection, by delivering antibiotics for a longer period of more than 1 month.

Repeated intracerebral microinjections: efficacy in studying brain functions.

Injection of chemicals into the brain has been considered as an important technique to study various functions of the brain. In these studies, as a rule, only one bilateral injection is given in one animal. This study was undertaken to evaluate the quality of the body temperature data obtained after first and second injections of methoxamine and artificial cerebrospinal fluid into the medial preoptic area. Though there was quantitative decrease in the effects produced after the second injection of the drug, there was no significant change in the effects produced by the second injections of artificial cerebrospinal fluid, which was used as a vehicle. Results of this study support the earlier recommendation to perform only one injection in any of the brain sites for evaluating the effect of any drug. But the vehicle can be administered as a second injection, without compromising on the quality of data.

Efeitos da drenagem do líquido cérebro-espinhal na prevenção da paraplegia após o clampeamento da aorta torácica em modelo canino / Effects of cerebrospinal fluid drainage in the prevention of paraplegia after thoracic aorta cross-claping in a canine model

Objetivos: Determinar se a drenagem do líquido cérebro-espinhal poderia aumentar a pressão de perfusão da medula espinhal e prevenir a ocorrência de paraplegia após o clampeamento da aorta torácica em cães, além de correlacionar a pressão de perfusão da medula espinhal ao estado neurológico dos animais e ao grau de injúria histológica de suas medulas. Métodos: Os animais do grupo I (n=6)foram submetidos a uma toracotomia lateral esquerda sem clampeamento da aorta torácica; os animais do Grupo II (n=6) foram submetidos a uma toracotomia lateral esquerda com clampeamento da aorta torácica, e os animais do Grupo III (n=6)foram submetidos a uma toracotomia lateral esquerda com drenagem do líquido cérebro-espinhal, seguida de clampeamento da aorta torácica. Resultados: Todos os animais do Grupo II apresentaram lesão na medula espinhal; os animais do Grupo I e III eram neurologicamente normais (P=0,00108), A pressão de perfusão da medula espinhal dos animais dos Grupos I e III foi maior que a dos animais do Grupo II (P=0,000). A histologia da medula espinhal dos Grupos I e III mostrou aspecto normal; no Grupo II havia infarto dos neurônios motores. Conclusões: A drenagem do líquido cérebro-espinhal foi eficiente em diminuir o índice de paraplegia após clampeamento da aorta torácica em cães. Deve-se esse efeito protetor à redução da pressão do líquido cérebro-espinhal, com o conseqüente aumento da pressão de perfusão da medula espinhal.