Hypoglycemia after Mitral Valve Repair in Dogs.

Hypoglycemia has not been previously reported as a postoperative complication of mitral valve repair (MVR) in dogs; however, the authors have encountered cases of hypoglycemia after MVR. This study aimed to determine the incidence of hypoglycemia in dogs after MVR and investigate its causes. Blood glucose levels were measured at multiple timepoints in dogs undergoing MVR. Simultaneously, insulin and glucagon blood concentrations in dogs with hypoglycemia preoperatively and postoperatively were compared to verify the physiological responses to hypoglycemia. Furthermore, risk factors for hypoglycemia, using variables selected based on the characteristics of MVR and dogs undergoing MVR, were examined prospectively. The incidence of hypoglycemia after MVR was 14.2%, and plasma glucagon concentrations increased in these dogs (mean: 260 pg/mL and 644 pg/mL pre- and postoperatively, p < 0.001), whereas serum insulin concentrations decreased (median: 0.50 ng/mL and 0.29 ng/mL pre- and postoperatively, p = 0.002). Therefore, hyperinsulinemia or hypoglucagonemia is unlikely to be the cause of postoperative hypoglycemia. The identified risk factors for hypoglycemia included low body weight and asymptomatic myxomatous mitral valve disease. Monitoring blood glucose levels after MVR should be included in the standard hospitalization plan to prevent hypoglycemic emergencies in dogs.

Preoperative and postoperative high angular resolution diffusion imaging tractography of cerebellar pathways in posterior fossa tumors.

This study aimed to utilize high angular resolution diffusion magnetic resonance imaging (HARDI) tractography in the mapping of the pathways of the cerebellum associated with posterior fossa tumors (infratentorial neoplasms) and to determine whether it is useful for preoperative and postoperative evaluation. Retrospective data from 30 patients (age 2-16 yr) with posterior fossa tumor (17 low grade, 13 high grade) and 30 age-sex-matched healthy controls were used. Structural and diffusion-weighted images were collected at a 3-tesla scanner. Tractography was performed using Diffusion Toolkit software, Q-ball model, FACT algorithm, and angle threshold of 45 degrees. Manually assessed regions of interest were placed to identify reconstructed fiber pathways passing through the superior, medial, and inferior cerebellar peduncles for the preoperative, postoperative, and healthy control groups. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), and track volume measures were obtained and analyzed. Statistically significant differences were found between the preop/postop, preop/control, and postop/control comparisons for the volume of the tracts in both groups. Displacement and disruption of the pathways seemed to differ in relation to the severity of the tumor. The loss of pathways after the operation was associated with selective resection during surgery due to tumor infiltration. There were no FA differences but significantly higher ADC in low-grade tumors, and no difference in both FA and ADC in high-grade tumors. The effects of posterior fossa tumors on cerebellar peduncles and reconstructed pathways were successfully evaluated by HARDI tractography. The technique appears to be useful not only for preoperative but also for postoperative evaluation.

Brain morphological analysis in PTEN hamartoma tumor syndrome.

PTEN hamartoma tumor syndrome (PHTS) is a spectrum of hereditary cancer syndromes caused by germline mutations in PTEN. PHTS is of high interest, because of its high rate of neurological comorbidities including macrocephaly, autism spectrum disorder, and intellectual dysfunction. Since detailed brain morphology and connectivity of PHTS remain unclear, we quantitatively evaluated brain magnetic resonance imaging (MRI) in PHTS. Sixteen structural T1-weighted and 9 diffusion-weighted MR images from 12 PHTS patients and neurotypical controls were used for structural and high-angular resolution diffusion MRI (HARDI) tractography analyses. Mega-corpus callosum was observed in 75%, polymicrogyria in 33%, periventricular white matter lesions in 83%, and heterotopia in 17% of the PHTS participants. While gyrification index and hemispheric cortical thickness showed no significant differences between the two groups, significantly increased global and regional brain volumes, and regionally thicker cortices in PHTS participants were observed. HARDI tractography showed increased volume and length of callosal pathways, increased volume of the arcuate fasciculi (AF), and increased length of the bilateral inferior longitudinal fasciculi (ILF), bilateral inferior fronto-occipital fasciculi (IFOF), and bilateral uncinate fasciculus. A decrease in fractional anisotropy and an increased in apparent diffusion coefficient values of the AF, left ILF, and left IFOF in PHTS.

Evolution of Brain Connections: Integrating Diffusion MR Tractography With Gene Expression Highlights Increased Corticocortical Projections in Primates.

Diffusion MR tractography permits investigating the 3D structure of cortical pathways as interwoven paths across the entire brain. We use high-resolution scans from diffusion spectrum imaging and high angular resolution diffusion imaging to investigate the evolution of cortical pathways within the euarchontoglire (i.e., primates, rodents) lineage. More specifically, we compare cortical fiber pathways between macaques (Macaca mulatta), marmosets (Callithrix jachus), and rodents (mice, Mus musculus). We integrate these observations with comparative analyses of Neurofilament heavy polypeptide (NEFH) expression across the cortex of mice and primates. We chose these species because their phylogenetic position serves to trace the early evolutionary history of the human brain. Our comparative analysis from diffusion MR tractography, cortical white matter scaling, and NEFH expression demonstrates that the examined primates deviate from mice in possessing increased long-range cross-cortical projections, many of which course across the anterior to posterior axis of the cortex. Our study shows that integrating gene expression data with diffusion MR data is an effective approach in identifying variation in connectivity patterns between species. The expansion of corticocortical pathways and increased anterior to posterior cortical integration can be traced back to an extension of neurogenetic schedules during development in primates.

Bilateral thalamocortical abnormalities in focal cortical dysplasia.

BACKGROUND AND PURPOSE: Focal cortical dysplasia (FCD), a congenital malformation of the neocortex and one of the most common causes of medication resistant epilepsy in pediatric populations, can be studied noninvasively by diffusion tensor imaging (DTI). The present study aimed to quantify changes in the thalamus and thalamocortical pathways with respect to fractional anisotropy (FA), apparent diffusion coefficient (ADC), volume, and other common measures. MATERIALS AND METHODS: The study quantified data collected from pediatric patients with a prior diagnosis of FCD; 75 patients (35 females, 10.1 ±â€¯6.5 years) for analysis of thalamic volume and 68 patients (32 females, 10.2 ±â€¯6.4 years) for DTI analysis. DTI scans were taken at 3 Tesla MRI scanners (30 diffusion gradient directions; b = 1000 s/mm2 and 5 non diffusion-weighted measurements). DTI tractography was performed using the FACT algorithm with an angle threshold of 45 degrees. Manually delineated ROIs were used to compare the hemisphere containing the dysplasia to the contralateral hemisphere and controls. RESULTS: A significant decrease in the volume of the FCD hemisphere thalamus was detected as compared to the contralateral hemisphere. In comparison to controls, there was an observed reduction in tract volume, length, count, FA of thalami, and FA of thalamocortical pathways in FCD patients. FCD patients had higher odds of exhibiting high ADC in both the thalamus and thalamocortical pathways. CONCLUSION: The data implied a widespread reduction in structural connectivity of the thalamocortical network. MRI analysis suggests a potential influence of FCD on thalamic volume.

Pre-Adult MRI of Brain Cancer and Neurological Injury: Multivariate Analyses.

Brain cancer and neurological injuries, such as stroke, are life-threatening conditions for which further research is needed to overcome the many challenges associated with providing optimal patient care. Multivariate analysis (MVA) is a class of pattern recognition technique involving the processing of data that contains multiple measurements per sample. MVA can be used to address a wide variety of neuroimaging challenges, including identifying variables associated with patient outcomes; understanding an injury's etiology, development, and progression; creating diagnostic tests; assisting in treatment monitoring; and more. Compared to adults, imaging of the developing brain has attracted less attention from MVA researchers, however, remarkable MVA growth has occurred in recent years. This paper presents the results of a systematic review of the literature focusing on MVA technologies applied to brain injury and cancer in neurological fetal, neonatal, and pediatric magnetic resonance imaging (MRI). With a wide variety of MRI modalities providing physiologically meaningful biomarkers and new biomarker measurements constantly under development, MVA techniques hold enormous potential toward combining available measurements toward improving basic research and the creation of technologies that contribute to improving patient care.

Efficient generation of vesicular stomatitis virus (VSV)-pseudotypes bearing morbilliviral glycoproteins and their use in quantifying virus neutralising antibodies.

Morbillivirus neutralising antibodies are traditionally measured using either plaque reduction neutralisation tests (PRNTs) or live virus microneutralisation tests (micro-NTs). While both test formats provide a reliable assessment of the strength and specificity of the humoral response, they are restricted by the limited number of viral strains that can be studied and often present significant biological safety concerns to the operator. In this study, we describe the adaptation of a replication-defective vesicular stomatitis virus (VSVΔG) based pseudotyping system for the measurement of morbillivirus neutralising antibodies. By expressing the haemagglutinin (H) and fusion (F) proteins of canine distemper virus (CDV) on VSVΔG pseudotypes bearing a luciferase marker gene, neutralising antibody titres could be measured rapidly and with high sensitivity. Further, by exchanging the glycoprotein expression construct, responses against distinct viral strains or species may be measured. Using this technique, we demonstrate cross neutralisation between CDV and peste des petits ruminants virus (PPRV). As an example of the value of the technique, we demonstrate that UK dogs vary in the breadth of immunity induced by CDV vaccination; in some dogs the neutralising response is CDV-specific while, in others, the neutralising response extends to the ruminant morbillivirus PPRV. This technique will facilitate a comprehensive comparison of cross-neutralisation to be conducted across the morbilliviruses.

Longitudinal changes in diffusion properties in white matter pathways of children with tuberous sclerosis complex.

BACKGROUND: Abnormal white matter development in patients with tuberous sclerosis complex, a multisystem hamartomatous disorder caused by aberrant neural proliferation and axonal maturation, may be associated with poorer neurocognitive outcomes. The purpose of this study is to identify predictors of longitudinal changes in diffusion properties of white matter tracts in patients with tuberous sclerosis complex. METHODS: Diffusion magnetic resonance imaging was carried out in 17 subjects with tuberous sclerosis complex (mean age, 7.2 ± 4.4 years) with at least two magnetic resonance imaging scans (mean number of days between scans, 419.4 ± 105.4). There were 10 males; 5 of 17 had autism spectrum disorder and 10 of 17 had epilepsy. Regions of interest were placed to delineate the internal capsule/corona radiata, cingulum, and corpus callosum. The outcomes were mean change in apparent diffusion coefficient and fractional anisotropy. Data were analyzed using Pearson's correlation and multiple linear regression analyses. RESULTS: Gender was a significant predictor of mean change in apparent diffusion coefficient in the left internal capsule, right and left cingulum bundles, and corpus callosum and a significant predictor of mean change in fractional anisotropy in the corpus callosum. Epilepsy was a significant predictor of mean change in apparent diffusion coefficient in the left internal capsule. Autism spectrum disorder was not predictive of diffusion changes in any of the studied pathways. CONCLUSION: Clinical variables, including gender and epilepsy, have an effect on the development of white matter pathways. These variables should be taken into consideration when counseling tuberous sclerosis complex patients and in future imaging studies in this population.

[Comparison of Tracheal Intubation Performance between Macintosh Direct Laryngoscope and McGRATH® MAC Video Laryngoscope among Anesthesia Trainees].

BACKGROUND: From April 2013, Macintosh direct laryngoscopes (DL) were replaced by McGRATH® MAC video laryngoscopes (VL), and VL were distributed in all of our operating rooms and used as routine first choice devices. Purpose of this study was to compare the success rate of the first attempt tracheal intubation by the trainees with VL and DL. Incidence of tracheal intubation related injuries were also assessed. MATERIALS AND METHODS: We reviewed anesthesia chart database in which tracheal intubations were provided by anesthesia trainees with experience of less than 3 months. Patient demographics, Mallampati classification and tracheal intubation profiles including type of the tracheal tube and devices were recorded. RESULTS AND DISCUSSION: The first attempt success rate was 78.6% with DL and 92.8% with VL (P < 0.001). More than 2 repeated trial incidence was 5.2% with DL and 1.3% with VL (P < 0.001). Incidence of mucosal injury was lower with DL than VL. CONCLUSIONS: VL notably improved the first success rate of tracheal intubation compared with DL among trainees.

[Metoclopramide Induced Acute Dystonia during Intravenous Patient-controlled Analgesia with Droperidol].

A patient developed acute dystonia following intravenous administration of metocroplamide 20 mg. A 34-year-old woman underwent right hepatectomy, under general anesthesia managed with desflurane, remifentanil, and rocuronium. At the start of surgery, droperidol 1.5 mg was given intravenously for anti-emetic prophylaxis. Operation was completed uneventfully. Intravenous patient-controlled analgesia (i.v.-PCA) with fentanyl, containing droperidol, was selected for postoperative pain management The patient showed a reasonable postoperative course; however, around 15 hours post-operatively, she complained of nausea, although droperidol 2.625 mg had been administrated (maximum dose). Nausea subsequently disappeared following intravenous metocroplamide 20 mg, and i.v.-PCA was terminated. The patient gradually complained of excessive sleepiness. Finally, she showed akinesis and bilateral oculomotor disturbance 140 minutes after metocroplamide administration. However, her vital signs remained stable. Examinations including magnetic resonance imaging, electroencephalogram, and blood test did not show abnormalities. She was diagnosed with acute dystonia. She recovered without medications 300 minutes after the onset of akinesis. She could communicate with her eyes, opening/closing, throughout this episode. The effects of antiemetics acting on different receptors are additive. However, we should remember that coadministration of metocroplamide and butyrophenone induces extrapyramidal signs like acute dystonia. Intraoperative management extending beyond postoperative antiemetic therapy is necessary.