Water- and fat-suppressed proton projection MRI (WASPI) of rat femur bone.

Investigators often study rats by microCT to investigate the pathogenesis and treatment of skeletal disorders in humans. However, microCT measurements provide information only on bone mineral content and not the solid matrix. CT scans are often carried out on cancellous bone, which contains a significant volume of marrow cells, stroma, water, and fat, and thus the apparent bone mineral density (BMD) does not reflect the mineral density within the matrix, where the mineral crystals are localized. Water- and fat-suppressed solid-state proton projection imaging (WASPI) was utilized in this study to image the solid matrix content (collagen, tightly bound water, and other immobile molecules) of rat femur specimens, and meet the challenges of small sample size and demanding submillimeter resolution. A method is introduced to recover the central region of k-space, which is always lost in the receiver dead time when free induction decays (FIDs) are acquired. With this approach, points near the k-space origin are sampled under a small number of radial projections at reduced gradient strength. The typical scan time for the current WASPI experiments was 2 hr. Proton solid-matrix images of rat femurs with 0.4-mm resolution and 12-mm field of view (FOV) were obtained. This method provides a noninvasive means of studying bone matrix in small animals.     

Sub-acute intoxication by Senna occidentalis seeds in rats.

Senna occidentalis (So) is a weed that grows in pastures along fences and in fields cultivated with cereals such as corn and soybean, and many reports have been showing intoxication with this plant in different animal species. It is also used in many medicinal purposes. The objective of the present study was to better evaluate the toxic effects of prolonged administration of So seeds to rats. Forty male Wistar rats were divided into four groups of 10 animals each, three of them respectively fed rations containing 1%, 2% and 4% So seeds, and the last one (control) fed commercial ration for a period of 2 weeks. Fourteen rats were also used in a pair-feeding (PF) experiment. The rats of the experimental groups showed lethargy, weakness, recumbency, depression and emaciation. Two rats of the 4% group and two of the PF group died during the experiment. Histopathological study showed fiber degenerations in the skeletal (Tibial, pectoral and diaphragm) and cardiac muscles. In the liver parenchyma, was observed vacuolar degeneration and, in the kidney, mild nefrosis in the proximal convoluted tubules. All of these alterations occurred in a dose-dependent fashion. Moderate to severe degeneration and spongiosis in the central nervous system, especially in cerebellum. Electron microscopy revealed mitochondrial lesions in all analyzed tissues.     

Users' awareness of factors associated with complications during pill use

This study compared the frequency of factors and diseases that contribute to the risks of oral contraceptive use among current users and non-users of oral contraception in order to evaluate the users' awareness of factors associated with complications during oral contraceptive use. Data from 5317 current users and 8863 non-users in the state of São Paulo, Brazil, were collected using questionnaires requesting information on the following variables: use of oral contraceptives, age, weight, smoking status, and the presence or history of hypertension, diabetes, cardiopathies, painful varicose veins, and epilepsy. Half of the users had some risk factors, and 17.4% were at high risk of complications from oral contraceptive use. Risk factors and diseases which appeared to be poorly known by the population as increasing the risk of oral contraceptive use were smoking, hypertension and painful varicose veins. Only a small percentage of the population appeared to know that these diseases and factors could increase the risk of health problems during oral contraceptive use. The results suggest a lack of information among users and providers on factors which are associated with an increased risk of health problems during use of oral contraceptives.

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Resumen Este estudio comparó la frecuencia de factores y enfermedades que contribuyen al riesgo de los anticonceptivos orales (AO) entre usuarias y no usuarias corrientes de anticonceptivos orales a fin de evaluar el grado de conocimiento entre las usuarias de los factores asociados con complicaciones durante el uso de AO. Se recopilaron datos de 5317 usuarias y 8863 no usuarias corrientes del Estado de S@o Paulo, Brasil, utilizando cuestionarios en los que se solicitabe información acerca de las siguientes variables: uso de AO, edad, peso, fumadora/no fumadora y la presencia o historia de hipertensión, diabetes, cardiopatías, várices dolorosas y epilepsia. La mitad de las usuarias tenían algunos factores de riesgo y el 17,4% de ellas corrían un alto riesgo de complicaciones por el uso de anticonceptivos orales. Los factores de riesgo y enfermedades que parecían ser poco conocidos por la población como tendientes a aumentar el riesgo del uso de anticonceptivos orales eran el fumar, la hipertensión y las várices dolorosas. Sólo un pequeño porcentaje de la población parecía saber que estas enfermedades y factores podían aumentar el riesgo de problemas de salud durante el uso de anticonceptivos orales. Los resultados sugieren una falta de información de las usuarias y proveedores con respecto a factores que están asociados con un riesgo mayor de problemas de salud durante el uso de anticonceptivos orales.

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Resumé Pour évaluer dans quelle mesure les utilisatrices et non utilisatrices de contraceptifs oraux sont sensibilisées aux facteurs associés à des complications, cette étude a comparé la fréquence des facteurs et des maladies qui contribuent au risque que présente l'utilisation de ces contraceptifs. Dans l'Etat de Sao Paulo (Brésil), des données ont été recueillies auprès de 5317 utilisatrices et 8863 non utilisatrices, au moyen de questionnaires demandant des renseignements concernant les variables suivantes: utilisation de contraceptifs oraux, âge, poids, tabagisme, présence ou antécédents d'hypertension, diabète, cardiopathies, varices douloureuses et épilepsie. La moitié des utilisatrices présentaient certains facteurs de risque et 17,4% des facteurs de risque élevé de complications résultant de l'utilisation de contraceptifs oraux. Les facteurs de risque et les maladies dont la population semblait mal connaître l'effet d'augmentation des risques qu'entrîne l'ingestion de contraceptifs oraux étaient le tabagisme, l'hypertension et les varices douloureuses. Un faible pourcentage seulement de la population paraissait savoir que ces maladies et facteurs pouvaient accroître les risques de problèmes de santé durant l'utilisation des contraceptifs oraux. Les résultats suggèrent que les utilisatrices et les pourvoyeurs des services de contraception ne sont pas suffisamment informés des facteurs associés à un risque accru de problèmes de santé durant l'utilisation des contraceptifs oraux.

     

Catheter ablation by low energy DC shocks for successful management of atrial flutter.

OBJECTIVE--To assess the effects of low energy ablation of the substrate for atrial flutter. DESIGN--Initial retrospective analysis of patients undergoing low energy ablation of the atrioventricular node for refractory atrial flutter (group 1) was followed by a prospective assessment of low energy ablation in the posterio-inferior right atrium for the same condition (group 2). SETTING--Tertiary referral centre for management of cardiac arrhythmias. PATIENTS--Seven men (aged 50-67 years) with refractory atrial flutter. INTERVENTIONS--Multiple (3-10) low energy DC shocks with a cumulative energy of 100-245 J in the region of the atrioventricular node in group 1 and 12-15 low energy DC shocks (cumulative energy 110-235 J) guided by the anatomical landmarks of the triangle of Koch and applied directly to the atrial wall. MAIN OUTCOME MEASURE--Freedom from recurrence of atrial flutter. RESULTS--In group 1 despite initial complete atrioventricular block in three patients, atrioventricular conduction had resumed in all by one month. All four, however, were in sinus rhythm at follow up six to 13 months later. Two of the three patients in group 2 were free of atrial flutter at follow up three to four months after ablation. CONCLUSION--Ablation of the atrial flutter substrate with low energy DC shocks is feasible. Precise electrophysiological mapping is not necessary.     

Anti-Trypanosoma-cruzi-proteinase antibodies and immunoprotection in experimental Chagas' disease.

To verify whether anti-Trypanosoma-cruzi-proteinase antibodies are able to play a role in the development of Chagas' disease, CBA/J and C57BL/6 mice were immunized with purified proteinase fractions: antibody production was studied and passive immunization experiments were carried out. No significant differences were observed in the titre, isotype composition and specificity of the antibodies produced by the mouse strains. Immune sera produced in one strain was able to protect mice of both strains, provided that the challenge did not exceed the number of parasites corresponding to 30-fold the LD50. The data presented suggest that anti-proteinase antibodies may play a role in immunoprotection.     

Cognitive consequences of early phase of literacy.

The effect of the degree of illiteracy (complete or incomplete) on phonological skills, verbal and visual memory and visuospatial skills is examined in 97 normal Brazilian adults who considered themselves illiterate, and 41 Brazilian school children aged 7 to 8 years, either nonreaders or beginning readers. Similar literacy effects were observed in children and in adults. Tasks involving phonological awareness and visual recognition memory of nonsense figures distinguish the best nonreaders and beginning readers. Children performed better than adults at oral repetition of short items and figure recall, and adults better than children at semantic verbal fluency, digit span, and word list recall. A principal component analysis of the correlations between tasks showed that phonological awareness/reading, phonological memory/oral repetition, and semantic verbal memory/fluency tasks, generated different components. The respective role of culturally based preschool activities and literacy on the cognitive functions that are explored in this study is discussed.