Transient bilateral blindness associated with presumptive idiopathic pachymeningitis in a 22-year-old Irish Sport Horse

A 22-year-old Irish Sport Horse presented following a period of bilateral blindness with subsequent spontaneous resolution. Brain magnetic resonance imaging (MRI) demonstrated features consistent with pachymeningitis. Cerebrospinal fluid (CSF) analysis revealed increased numbers of basophils, suggestive of an immunologic or neoplastic aetiology. It was suspected that the enlarged meninges led to compression of the optic nerves in the optic canals, causing bilateral blindness. Initial spontaneous remission, as seen in this case, has been reported in human patients with this condition. Pachymeningitis should be considered as a possible cause of cranial nerve deficits, including bilateral and unilateral blindness, in horses.     

Resveratrol protects cortical neurons in infant rats with bacterial meningitis through miR-223-3p/NLRP3 pathway

AIM To investigate the protective effect of resveratrol (Res) on cortical neurons in rat bacterial meningitis (BM) model. METHODS Group B hemolytic Streptococcus was injected via the posterior cistern to establish a BM model. Resveratrol was administered intranasally and microRNA-223-3p (miR-223-3p) antagomir was administered by intracerebroventricular injection. HE staining was used to observe the pathological changes of the brain tissue. Loeffler scoring method was used to evaluate the neurobehavioral functions. TUNEL staining was used to detect neuronal apoptosis. The expression of interleukin-1β (IL-1β), IL-18, glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule 1 (Iba1) was detected by immunofluorescence staining. The protein levels of nucleotide-binding oligomerization domain-like receptor protein 3 （NLRP3）, cleaved caspase-1, IL-1β and IL-18 were determined by Western blot. The expression level of miR-223-3p was detected by RT-qPCR. Online software TargetScan was used to search for the complementary nucleotide sequences between miR-223-3p and NLRP3 mRNA. RESULTS Compared with sham group, the thickness of meninges in BM model was increased, the neurological score was decreased (P<0.05), and the number of TUNEL positive neurons was increased significantly (P<0.05). Astrocytes and microglia were activated, the fluorescence intensity of IL-1β and IL-18 was increased (P<0.05), and the expression levels of NLRP3, cleaved caspase-1, IL-1β, IL-18 and miR-223-3p were increased (P<0.05). Compared with BM group, after treatment with resveratrol, the neurological score was increased (P<0.05), the number of TUNEL positive neurons was decreased significantly (P<0.05), and the inflammatory response of astrocytes and microglia was suppressed. The fluorescence intensity of IL-1β and IL-18 was decreased (P<0.05), the protein levels of NLRP3, cleaved caspase-1, IL-1β and IL-18 were decreased (P<0.05), and the expression level of miR-223-3p was increased (P<0.05). A nucleotide sequence in the 3'-UTR of NLRP3 mRNA might be targeted by miR-223-3p. In the brain of rat BM model, compared with antagomir control group, the expression of NLRP3 was increased in miR-223-3p antagomir group with resveratrol treatment (P<0.05). CONCLUSION Resveratrol may reduce the inflammatory death of cortical neurons in BM model of infant rats through miR-223-3p/NLRP3 pathway, thus playing a protective role for the neurons.     

Research Advances in Escherichia coli K1 Penetration Across Blood-brain Barrier

E.coli K1 strain is a representative strain of neonatal sepsis and meningitis, which causes disease by blood circulation to the brain. The molecular mechanism of E.coli K1 that adhering and invading the brain microvascular endothelial cells (BMECs) and cross the blood brain barrier (BBB) has been focused on by many scholars. In this review, we focused on the gene regulation mechanisms and signaling pathway of E.coli K1 crossing the blood brain barrier to understand the molecular mechanism of the infection caused by E.coli and provide reference for prevention and treatment programs.     

Effect of acquisition time and chemical fat suppression on meningeal enhancement on MR imaging in dogs

Our purpose was to characterize meningeal gadolinium enhancement on magnetic resonance (MR) imaging in dogs with inflammatory and neoplastic diseases, and to assess interobserver variability and the impact of delayed acquisition and chemical fat saturation on its conspicuity. Transverse T1-weighted FLAIR images were acquired prior to, and immediately following gadolinium injection (T0), and at 5 (T5) and 15-20 min delay (TD), with and without fat suppression, in 155 consecutive dogs imaged for suspected brain disease. The agreement on meningeal enhancement was globally substantial (kappa = 0.61) and the likelihood of obtaining a definite diagnosis was significantly increased with the use of fat suppression (P < or = 0.004). Meningeal enhancement was judged definitively present by consensus in 46 of 155 (30%) dogs. Of these, meningeal enhancement was characterized qualitatively and quantitatively in 30 dogs with a clinical diagnosis (18 inflammatory, 11 neoplastic, 1 infarct), and image sequences were compared. Meningeal enhancement was more often diffuse and leptomeningeal in animals with inflammation versus neoplasia (50% vs. 42%, and 69% vs. 48%, respectively), but significant associations were not found. Meningeal thickness and contrast ratio were higher with neoplasia (P < or = 0.02), but results did not vary significantly between series for either group. Yet, images with fat suppression were most useful 50% of the time for definite diagnosis and/or characterization of meningeal enhancement. While delayed image acquisition following gadolinium injection does not improve characterization of meningeal enhancement in dogs, fat suppression is beneficial qualitatively.     

CANINE MENINGEAL DISEASE: ASSOCIATIONS BETWEEN MAGNETIC RESONANCE IMAGING SIGNS AND HISTOLOGIC FINDINGS

In order to compare the accuracy of MR sequences for diagnosis of meningeal disease, MR images of the brain, and histopathologic specimens including the meninges of 60 dogs were reviewed retrospectively by independent observers in a cross‐sectional study. MR images included T1‐weighted pre‐ and postgadolinium images, subtraction images, T2‐weighted images, and T2‐weighted fluid‐attenuated inversion‐recovery (FLAIR) images. Pathologic changes affected the pachymeninges in 16 dogs, leptomeninges in 35 dogs, and brain in 38 dogs. The meninges were normal in 12 dogs. Meninges were classified histopathologically as normal (grade 0), slightly or inconsistently affected (grade 1), or markedly affected (grade 2). When applying relaxed pathologic criteria (grades 0 and 1 considered normal), the results of ROC analysis (area under curve, AUC) were: T1‐weighted postcontrast images 0.74; subtraction images 0.7; T2‐weighted images 0.68; FLAIR images 0.56. The difference in AUC between T1‐weighted postgadolinium images and FLAIR images was significant (P = 0.04). AUC for FLAIR images was not significantly different from 0.5. When applying strict pathologic criteria (only grade 0 considered normal), none of the MR sequences had AUC significantly different from 0.5. On the basis of T1‐weighted postgadolinium images and subtraction images, correct anatomic classification of lesions occurred more often for pachymeningeal than leptomeningeal lesions (P < 0.001). Overall, MR imaging had low sensitivity for diagnosis of meningeal pathology in dogs, particularly for changes affecting the leptomeninges. Subtraction images had similar accuracy to T1‐weighted postgadolinium images for meningeal lesions in dogs. T2‐weighted FLAIR images appear to have limited diagnostic utility for meningeal lesions.     

无乳链球菌感染尼罗罗非鱼的脑膜炎模型

目的：脑膜炎是罗非鱼无乳链球菌病的特征性临床症状,建立罗非鱼无乳链球菌脑膜炎模型,并制定相应的临床症状及组织病理学评分系统,对研究罗非鱼无乳链球菌病的致病机制具有十分重要的意义。方法：将健康罗非鱼43尾,随机分为4组：对照组(n=10)和试验组(n=33)。3组试验组根据不同感染剂量分为：10₆cfu组(n=11)、10₇cfu组(n=11)、10₈cfu组(n=11)。试验组分别将10₆、10₇、10₈CFU的无乳链球菌菌液腹腔注射罗非鱼复制脑膜炎模型。对感染罗非鱼的临床症状、剖检病变、脑组织(端脑、中脑、小脑、延脑)病理学进行判定,并结合细菌学检测,按照拟定的评分系统评价各组脑膜炎的造模效果,确定最佳造模方案。结果：各试验攻毒组罗非鱼感染后2天均出现不同程度死亡,未见明显神经症状。感染3天后鱼体开始出现异常活动的神经症状及突眼、角膜混浊等病理变化。病理组织学观察可见：蛛网膜下腔和脑软膜上有大量炎性渗出和染成蓝紫色微细颗粒的细菌团块,脑膜充血、水肿、疏松、增厚,有大量的中性白细胞等炎性细胞浸润;脑实质基质疏松水肿,呈海绵状;脑组织炎性细胞浸润,胶质细胞增生等软脑膜炎、脑膜脑炎症状。比较各组得分发现,10₇CFU组的无乳链球菌攻毒罗非鱼造模效果最好：临床症状显著而组内罗非鱼差异性最小,组织病理学观察患病罗非鱼病情和缓适中、利于观察研究。结论：使用10₇CFU无乳链球菌腹腔攻毒罗非鱼可在第3天成功构建脑膜炎模型,造模率为100%。     

Surgical management of a canine intracranial abscess due to a bite wound

Objective – To describe the successful surgical management of a brain abscess in a dog secondary to bite wound. Case Summary – A 10‐year‐old neutered female Welsh Corgi/Chihuahua, weighing 5.3 kg, was presented for evaluation of seizures, ataxia, and falling to the left 8 days after a presumptive fight with another dog. On examination at presentation, the dog was alert, responsive, and ambulatory with tetra‐ataxia, falling to the left, left‐sided postural deficits, and absent left menace response. Within 24 hours, the dog progressed to nonambulatory tetraparesis with minimal motor, absent postural reactions of all limbs, left nasal hypalgesia, reduced gag reflex, and depressed mentation. Computed tomographic images of the brain were suggestive of a bite wound fracture of the right parietal bone with secondary meningoencephalitis, right parietal lobe abscessation, and white matter edema adjacent to the bone fracture. A modified right rostrotentorial craniectomy was performed, the abscess was identified, contents of the abscess were removed, and the surgical site was flushed extensively before closing. Corynebacterium spp. was cultured from within the abscess. Within hours of surgery, the dog was quiet but alert, responsive, and sitting up in her cage. In addition to surgical intervention, intensive care, broad‐spectrum IV antimicrobials, and supportive therapy led to significant neurologic improvement with only occasional seizures and mild postural reaction deficits of the left hindlimb remaining. New or Unique Information Provided – Abscess formation within the CNS is uncommon in dogs and cats and is associated with a high mortality rate. In veterinary medicine the management of brain abscesses is controversial with limited information available regarding treatment. This is the first case report that demonstrates surgical intervention in combination with antimicrobial therapy can be used successfully in the treatment of a canine brain abscess.     

Pyogenic meningitis and trigeminal neuritis secondary to periodontogenic paranasal sinusitis in a red deer (Cervus elaphus)

An adult female red deer died of a severe seizure and dysbasia. Postmortem computed tomography (CT) and magnetic resonance imaging (MRI) were performed. On CT, deciduous right maxillary second and third premolar teeth were observed, and the right infraorbital canal was disrupted. MRI showed that the right trigeminal nerve was enlarged and the right subarachnoid cavity was occupied by fluid and gas. On gross examination, the right paranasal sinus, swollen muscles of the orbit and tonsils, right trigeminal nerve, and right cerebrum surface contained a yellowish-white, cheese-like pus. Based on these findings, the deer was believed to have developed pyogenic meningitis caused by a neuropathic infection secondary to periodontogenic paranasal sinusitis.