Toxoplasma gondii and Neospora caninum infections and factors associated in goats in the Parana state, Southern Brazil.

The aim of this study was to determine the occurrence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies and their associated factors among goats in farms from the Paraná state, South Brazil. The serological analysis was performed by indirect ELISA on 629 goat serum samples collected from 32 farms distributed in five mesorregions from the state. Seropositivity was observed in 30.7% of the animals for T. gondii, 6.3% for N. caninum, and 3.0% for both agents. Final multiple regression models showed that the use of assisted reproduction decreased the chance of seropositivity for T. gondii (PR=0.70) and the slaughtering site on the farm (PR=2.03) increased it. To N. caninum, the supplying concentrated feed to animals (OR=4.80) and animal pre-weaning death (OR=9.96) increased the chance of seropositivity. The variables associated with these seropositivities suggest deficiencies in sanitation and reproductive management. In addition, it recognizes critical points of infection for animal production management.

Toxoplasma gondii and Neospora caninum infections and factors associated in goats in the Parana state, Southern Brazil / Infecções por Toxoplasma gondii e Neospora caninum e fatores associados em caprinos no estado do Paraná, Sul do Brasil

Abstract The aim of this study was to determine the occurrence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies and their associated factors among goats in farms from the Paraná state, South Brazil. The serological analysis was performed by indirect ELISA on 629 goat serum samples collected from 32 farms distributed in five mesorregions from the state. Seropositivity was observed in 30.7% of the animals for T. gondii, 6.3% for N. caninum, and 3.0% for both agents. Final multiple regression models showed that the use of assisted reproduction decreased the chance of seropositivity for T. gondii (PR=0.70) and the slaughtering site on the farm (PR=2.03) increased it. To N. caninum, the supplying concentrated feed to animals (OR=4.80) and animal pre-weaning death (OR=9.96) increased the chance of seropositivity. The variables associated with these seropositivities suggest deficiencies in sanitation and reproductive management. In addition, it recognizes critical points of infection for animal production management.

Resumo O objetivo desse estudo foi avaliar a ocorrência de anticorpos anti-Toxoplasma gondii e anti-Neospora caninum e seus fatores associados em caprinos de propriedades do Estado do Paraná, Sul do Brasil. A análise sorológica foi realizada, utilizando-se ELISA indireto em 629 amostras de soro caprino, coletadas em 32 propriedades distribuídas em cinco mesorregiões do Estado. A soropositividade foi observada em 30,7% dos animais para T. gondii, 6,3% para N. caninum e 3,0% para ambos. Os modelos finais de regressão múltipla mostraram que o uso de reprodução assistida reduziu a chance de soropositividade para T. gondii (PR=0,70), enquanto a presença no local de abate na fazenda (PR=2,03) aumentou. Para N. caninum, o fornecimento de ração concentrada (OR=4,80) e a morte dos animais no pré-desmame (OR=9,96) aumentaram a chance de soropositividade. O estudo das variáveis associadas às soropositividades sugere deficiências no saneamento e no manejo reprodutivo dos Animais. Além disso, reconhece pontos críticos para a infecção no manejo da produção animal.

A theoretical study of the confinement effects on the energetics and vibrational properties of 4,4'-bipyridine adsorption on H-ZSM-5 zeolite.

The confinement effects of a zeolite framework on the adsorption of a bidentate 4,4'-bipyridine (44BPY) ligand on the straight channel of H-ZSM-5 have been investigated by density functional theory calculations using B3LYP, B3LYP-D3, M06-2X, M06-2X-D3 functionals, and the MP2 method with two basis sets 6-31+G* and 6-31++G(2d,2p). The straight channel is simulated by a realistic cluster model of 32 tetrahedra (T), having two aluminum atoms located in the straight and intersection regions, respectively. The potential energy surface of the double proton transfer reaction from the Brønsted acid sites of H-ZSM-5 to 44BPY is characterized by three minima corresponding to two monodentate ion pair complexes 44BPYH+/32T- and one bidentate ion pair complex 44BPYH22+/32T2- formed consecutively via two distinct pathways. No energy minimum is found for a neutral hydrogen bonding structure. The relative stabilities of these 44BPY adsorption complexes and the transition states connecting them do not exceed 4.9 and 4.2 kcal mol-1, respectively. Consequently equilibrium between the mono and bidentate complexes could be established. Our results clearly show that the adsorption energy for all complexes is substantially governed by the confinement effects executed through steric constraints and dispersive van der Waals interactions. The calculated vibrational frequencies and frequency shifts of 44BPY adsorbed as mono or diprotonated species are in good agreement with our Raman spectra of 44BPY occluded in H-ZSM-5 of different Si/Al ratios.

Vascular complications in diabetes and their prevention.

Diabetes mellitus is increasing throughout the world. Cardiovascular disease (CVD) accounts for up to 80% of excess mortality in this high-risk population. Patients with diabetes have the same CVD risk factors as those people without diabetes. However, these risk factors are much more powerful in diabetic patients. CVD risk is especially high for diabetic women, and premenopausal diabetic women lose all the protection normally afforded to them by female sex hormones. Controlled clinical trials have clearly demonstrated that rigorous treatment of blood pressure, dyslipidemia and platelet hyperaggrebility strikingly reduces CVD risk in diabetic patients. Strategies directed at interrupting the renin-angiotensin system (both tissue and systemic systems) and the use of 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors have proven to be especially beneficial for this high-risk population.

Wallerian degeneration and inflammation in rat peripheral nerve detected by in vivo MR imaging.

To investigate the role of MR imaging in wallerian degeneration, a series of animal models of increasingly complex peripheral nerve injury were studied by in vivo MR. Proximal tibial nerves in brown Norway rats were either crushed, transected (neurotomy), or transected and grafted with Lewis rat (allograft) or brown Norway (isograft) donor nerves. The nerves distal to the site of injury were imaged at intervals of 0-54 days after surgery. Subsequent histologic analysis was obtained and correlated with MR findings. Crush injury, neurotomy, and nerve grafting all resulted in high signal intensity along the course of the nerve observed on long TR/TE sequences, corresponding to edema and myelin breakdown from wallerian degeneration. The abnormal signal intensity resolved by 30 days after crush injury and by 45-54 days after neurotomy, when the active changes of wallerian degeneration had subsided. These changes were not seen in sham-operated rats. Our findings suggest that MR is capable of identifying traumatic neuropathy in a peripheral nerve undergoing active wallerian degeneration. The severity of injury may be reflected by the corresponding duration of signal abnormality. With the present methods, MR did not distinguish inflammatory from simple posttraumatic neuropathy.

Use of Gd-DTPA and fast gradient-echo and spin-echo MR imaging to demonstrate renal function in the rabbit.

The paramagnetic magnetic resonance (MR) imaging contrast agent gadolinium diethylenetriaminepentaacetic acid (DTPA) is freely filtered at the glomerulus and is neither secreted nor reabsorbed by the renal tubules. Fast MR imaging techniques, either gradient-echo or spin-echo, can be used to document the passage of Gd-DTPA through the renal tubules, as reflected by alteration in the MR signal intensity within the different anatomic regions of the kidney. Gradient-echo (repetition time of 35 msec, echo time of 7 msec, flip angles of 10 degrees-100 degrees) and spin-echo (repetition time of 35 msec, echo time of 8 msec) pulse sequences were used to acquire 20 consecutive images, one every 12 seconds, of the rabbit kidney. Both pulse sequences depicted the time course of Gd-DTPA distribution through the kidney but with distinctly different patterns of MR signal change. These dynamic MR images provide an MR nephrogram that directly demonstrates renal morphology and indirectly reflects the functional status of the renal vasculature, renal perfusion, and tubular concentrating ability.

High-resolution MR of the spinal cord in humans and rats.

Human and rat cervical spinal cords were imaged with high-resolution spin-echo and inversion-recovery pulse sequences in an experimental 1.9-T MR system. The gross morphology of the cord was easily discernible in fresh and fixed specimens, including the white and gray commissures, dorsal and ventral horns, and lateral and posterior funiculi. The T1, T2, and spin-density values for gray and white matter were determined from these images and were found to be 914 msec, 114 msec, and 71% for white matter other than the dorsal columns, and 946 msec, 87 msec, and 80% for gray matter in human spinal cords. These values are reduced considerably after formalin fixation: T1 to 56% (white matter) and 54% (gray matter) of prefixation values, T2 to 52% (white matter) and 70% (gray matter) of fresh values, and spin density to 90% (white matter) and 96% (gray matter) of prefixation values. Interestingly, the central gray matter demonstrates higher signal intensity than the white matter on both short and long TR/TE images. This intensity difference was observed for both human and rat spinal cords, before and after fixation, and can be explained by the relatively small T1 differences between gray matter and white matter and the gray matter-white matter spin-density ratios: 1.127 for fresh and 1.203 for fixed specimens.

Sodium NMR imaging of lung water in rats.

Coronal proton and sodium images of control rats and rats with either increased permeability edema produced by intravenous alloxan (300 mg/kg) or increased pressure edema produced by saline infusion (2 ml/min) were obtained. Axial chest CT images were used to monitor the development of pulmonary edema. Immediately after the imaging session compartmental lung water was measured gravimetrically. The sodium and proton imagings were done sequentially in a 31-cm-bore 1.9-T magnet without moving the animal. The anatomical boundaries of the lung on the proton images were transferred to the sodium images for calculation of the average sodium signal intensity which was determined by extrapolating the mean values from five echoes to time zero. The sodium signal intensity was correlated (r = 0.7) with the total water fraction. There was poor correlation (r = 0.56) with the extravascular water due to confounding by the sodium vascular signal.

Acute tubular necrosis: use of gadolinium-DTPA and fast MR imaging to evaluate renal function in the rabbit.

Sequential fast magnetic resonance (MR) images (repetition time = 33 ms, echo time = 7 ms, alpha = 22 degrees, one image every 12 s) were acquired using gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) (10 or 100 mumol/kg) to study perfusion and concentrating ability in normal rabbit kidneys and in kidneys with HgCl2-induced acute tubular necrosis (ATN). In normal rabbits receiving 100 mumol Gd-DTPA/kg a concentric region of decreased MR signal was observed. In sequential images the dark ring pattern migrated centripetally through the kidney moving from the corticomedullary junction to the inner medulla. The decrease in MR signal intensity occurred as a consequence of T2 relaxation (magnetic susceptibility) due to high concentration of Gd-DTPA within the tubules. This suggests that the dark ring pattern may serve as a qualitative feature indicative of the ability of the kidneys to concentrate. With the onset of HgCl2-induced ATN the pattern of enhancement due to Gd-DTPA administration changed markedly. Although the kidneys with ATN did continue to be perfused, the concentric dark ring pattern seen in normal kidneys receiving 100 mumol Gd-DTPA/kg was not observed. These results suggest that Gd-DTPA and fast imaging MR may provide a method of assessing perfusion and concentrating ability within the healthy or diseased kidney.

Hemorrhage and edema in acute spinal cord compression: demonstration by MR imaging.

Until the development of magnetic resonance (MR) imaging there was no nondestructive technique for monitoring the pathologic response to acute spinal cord trauma. The characteristic findings of hemorrhage, necrosis, and edema have been well described in animal models. We used a 1.4-T, animal imaging system to study acute cord contusions in rats. Contusions were induced by means of extradural aneurysm clip compression, and imaging was performed 3-5 hours after injury with short and long spin-echo (SE) sequences. Animals were killed immediately after imaging, and the gross anatomic and histologic findings were correlated with image appearances. On long SE sequences edema appeared as an area of high signal intensity that extended proximal and distal to the site of contusion. At the contusion site there was focal intraparenchymal hemorrhage which had low signal intensity on T2-weighted images, presumably owing to deoxyhemoglobin. MR imaging can be used to assess pathologic changes resulting from acute cord contusion and to aid in differentiating irreversible damage (hemorrhage) from potentially reversible edema.