MAGNETIC RESONANCE IMAGING OF THE CANINE BRAIN AT 7 T

The purpose of this study was to describe relevant canine brain structures as seen on T2-weighted images following magnetic resonance (MR) imaging at 7 T and to compare the results with imaging at 1.5 T. Imaging was performed on five healthy laboratory beagle dogs using 1.5 and 7 T clinical scanners. At 1.5 T, spin echo images were acquired, while gradient echo images were acquired at 3 T. Image quality and conspicuity of anatomic structures were evaluated qualitatively by direct comparison of the images obtained from the two different magnetic fields. The signal-to-nose ratio (SNR) and contrast-to-noise ratio (CNR) were calculated and compared between 1.5 and 7 T. The T2-weighted images at 7 T provided good spatial and contrast resolution for the identification of clinically relevant brain anatomy; these images provided better delineation and conspicuity of the brain stem and cerebellar structures, which were difficult to unequivocally identify at 1.5 T. However, frontal and parietal lobe and the trigeminal nerve were difficult to identify at 7 T due to susceptibility artifact. The SNR and CNR of the images at 7 T were significantly increased up to 318% and 715% compared with the 1.5 T images. If some disadvantages of 7 T imaging, such as susceptibility artifacts, technical difficulties, and high cost, can be improved, 7 T clinical MR imaging could provide a good experimental and diagnostic tool for the evaluation of canine brain disorders.     

Intestinal antiinflammatory activity of a lyophilized infusion of Turnera ulmifolia in TNBS rat colitis

Turnera ulmifolia is a plant popularly known in Brazil and South America as chanana. Some species of Turnera are widely used in folk medicine for different types of inflammatory diseases. In this study, the preventive intestinal antiinflammatory activity of a lyophilized infusion obtained from the aerial parts of T. ulmifolia was tested in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis. The results obtained revealed that pretreatment to colitic rats with the extract, at 250 and 500 mg/kg, significantly attenuated the colonic damage induced by TNBS. This beneficial effect was associated with an improvement in the colonic oxidative status, since the infusion prevented the glutathione depletion that occurred as a consequence of the colonic inflammation. On the other hand, this antioxidant activity was confirmed in in vitro studies. In conclusion, the preventive effect exerted by the lyophilized infusion of T. ulmifolia in the TNBS model of rat colitis is probably related to its antioxidant properties, due to its flavonoids content.     

Amelioration of Hexachlorocyclohexane-Induced Oxidative Stress by Amaranth Leaves in Rats

The effect of prefeeding dehydrated amaranth leaves (AL), at 10 and 20% levels on hexachlorocyclohexane (HCH)-induced free radical stress in rat liver was evaluated. The HCH-induced raise in malonadialdehyde (MDA), conjugated dienes and hydroperoxides was diminished by AL. The effect of AL was highly effective with respect to reduction in these cytotoxic products, especially at 20% level. AL intake resulted in a significant increase in hepatic vitamin A and glutathione (GSH). However, the AL consumption reduced hepatic tocopherols. Feeding of AL at 10%level increased the hepatic glucose-6-phosphate dehydrogenase (G-6-PDH) activity while that at 20% level increased the hepatic glutathione reductase (GSSGR) as well, in addition to G-6-PDH. Amaranth leaves at 10 and 20% levels of feeding reduced the hepatic superoxide dismutase and glutathione peroxidase (GSH-Px) activities. The pre-feeding of AL resulted in the reversal of HCH-induced alteration in GSH-Px and G-6-PDH activities. The significant reduction in the level of glutathione S-transferase brought about by HCH was restored to control level by feeding 20% AL. It is concluded that the consumption of AL at 20% level produces reduction in the HCH-induced impairment of antioxidant status in rat liver.     

RP-HPLC法检测大鼠海马中4种氨基酸类神经递质含量的研究

建立了RP-HPLC测定大鼠海马中4种氨基酸类神经递质含量的方法。以2,4-二硝基氟苯(DNFB)为衍生化试剂进行柱前衍生,色谱条件为Diamonsil C18(4.6mm×200mm,5μm)色谱柱,乙腈和醋酸钠缓冲液为流动相,采用二元梯度洗脱,UV350nm检测。结果显示:在18min内,4种氨基酸分离完全,在0.01~100μg/mL范围内线性关系良好,天冬氨酸(Asp)、谷氨酸(Glu)、甘氨酸(Gly)、γ-氨基丁酸(GABA)相关系数分别为0.9985、0.9976、0.9943、0.9924;日内变异系数分别为2.4%、3.8%、3.2%和3.5%;标准加入平均回收率分别为94.80%、93.93%、92.69%和96.74%。     

桐子叶水提物对小鼠的抗敏作用研究

[目的]研究桐子叶水提物对小鼠的抗敏作用。[方法]用卵清蛋白作为致敏抗原,制作小鼠致敏模型,豌察桐子叶水提物对小鼠过敏反应的作用。[结果]高、中浓度组桐子叶水提物对卵清蛋白引起的小鼠过敏反应均有明显的抑制作用。[结论]桐子叶水提物对卵清蛋白致敏的小鼠有明显的抗敏作用。     

RETROSPECTIVE COMPARISON OF THREE‐DIMENSIONAL CONFORMAL RADIATION THERAPY VS. PREDNISOLONE ALONE IN 30 CASES OF CANINE INFRATENTORIAL BRAIN TUMORS

Infratentorial tumors are relatively infrequent in dogs and a lack of data makes it difficult to offer prognostic information. Untreated, dogs with these neoplasms have shorter survival times than those with supratentorial tumors. The role of radiation therapy (RT) in the management of infratentorial tumors is poorly defined and tumoral/peritumoral swelling in this site is a potential cause of serious acute side effects. The aim of this retrospective, cohort study was to describe cases of infratentorial tumors treated with fractionated three‐dimensional conformal RT (3D CRT) and glucocorticoids (GC), and compare outcomes and survival with dogs affected by tumors in the same location that received GC alone. Thirty patients with a MRI diagnosis of infratentorial tumors were recruited (15 received RT and GC and 15 GC alone). None had mentation changes at presentation. For both groups, MRI and medical records were reviewed; and factors associated with survival were evaluated with Kaplan–Meier product limit survival and Cox regression analysis. Overall median survival time (MST) was 294 days (95% CI 42–545). The MST in the RT group was 756 days (95% CI 209–1302) vs. 89 days (95% CI 34.7–143.3 days) for those dogs treated palliatively with GC alone. This difference was statistically significant (P = 0.001). No other factors (including neurological signs, MRI features, tumor volume and total RT dose) were statistically associated with survival in the RT group. This study suggests that 3D CRT offers a survival advantage for dogs with infratentorial tumors compared to GC alone, and significant complications are uncommon.     

Molecular signalling pathways in canine gliomas

In this study, we determined the expression of key signalling pathway proteins TP53, MDM2, P21, AKT, PTEN, RB1, P16, MTOR and MAPK in canine gliomas using western blotting. Protein expression was defined in three canine astrocytic glioma cell lines treated with CCNU, temozolamide or CPT‐11 and was further evaluated in 22 spontaneous gliomas including high and low grade astrocytomas, high grade oligodendrogliomas and mixed oligoastrocytomas. Response to chemotherapeutic agents and cell survival were similar to that reported in human glioma cell lines. Alterations in expression of key human gliomagenesis pathway proteins were common in canine glioma tumour samples and segregated between oligodendroglial and astrocytic tumour types for some pathways. Both similarities and differences in protein expression were defined for canine gliomas compared to those reported in human tumour counterparts. The findings may inform more defined assessment of specific signalling pathways for targeted therapy of canine gliomas.     

A complication probability planning study to predict the safety of a new protocol for intracranial tumour radiotherapy in dogs

Technical advances make it possible to deliver radiation therapy for canine intracranial tumours in fewer fractions, under the assumption of equivalent tumour control. With the aim of estimating the late toxicity risk profile for various tumour sizes and locations, the present paper evaluates the normal tissue complication probability (NTCP) values for the intracranial organs at risk. By making isoeffect calculations, a new 10‐fraction radiation protocol was developed with the same tumour control probability (TCP) as a currently used 20‐fraction standard protocol, and complication risk profiles for brain, brainstem and optic chiasm were modelled using a representative population of 64 dogs with brain tumours. For >59% of cases, the new 10‐fraction protocol yielded an acceptable, low risk estimate of late toxicity (<10%). Our calculations suggest that it may be safe to treat small to intermediate‐sized tumours that are neither located near the optic chiasm nor at the brainstem with 10 daily fractions of 4.35 Gy.     

国医大师张学文辨治脑萎缩经验

国医大师张学文认为脑萎缩的中医病机主要是肾虚血瘀、气虚血瘀、颅脑水瘀导致脑髓失于精血濡养,脑髓不健。髓海不足和脑髓不健是本,脑络痹阻、清阳不升、浊气不降是标,本病往往虚实夹杂,纯虚者少,虚中夹实者多。宜滋肾荣脑,治当补气和血、祛瘀利水、解郁化痰、益肾活血。     

The effects of Saw palmetto on flumethrin-induced lipid peroxidation in rats

In the present study, 40 male Wistar albino rats were used and divided into 4 groups. The first group served as the control group; the second group was administered Saw palmetto extract at the dose of 20 mg/kg/bw; the third group was administered flumethrin at the dose of 15 mg/kg/bw; and the fourth group was administered a combination of 20 mg/kg/bw Saw palmetto extract and 15 mg/kg/bw flumethrin, for 21 days, orally. After the trial period, blood and tissue (liver, kidney and brain) samples were taken from the rats. Saw palmetto extract did not cause significant alterations in plasma and tissue malondialdehyde (MDA) levels, serum and tissue nitric oxide (NO) levels, erythrocyte and tissue superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities when compared to the controls (p > 0.05). Flumethrin led to increased plasma and tissue MDA levels, serum and tissue NO levels, tissue GSH-Px activities and decreased erythrocyte and tissue SOD and CAT activities, and erythrocyte GSH-Px activity, compared to the controls (p < 0.05). The flumethrin and Saw palmetto extract combination increased erythrocyte SOD activity and decreased brain GSH-Px activity as compared to flumethrin (p < 0.05). In conclusion, it was determined that Saw palmetto extract did not cause any negative effect on the prooxidant-antioxidant balance. While flumethrin stimulated lipid peroxidation; Saw palmetto extract at the dose of 20 mg/kg/bw did not exhibit enough antioxidant effect in rats.