Pancreatic enzyme activity in the bile of healthy cats and its association with biliary morphology.

BACKGROUND: In human medicine, congenital maljunction of the common bile duct (CBD) and main pancreatic duct (MPD), or pancreatobiliary maljunction (PBM), is a known cause of cholecystitis. OBJECTIVE: Pancreatic enzyme activity in the bile (a diagnostic marker for PBM) of healthy cats was measured to determine normal values and evaluate its relationship with biliary morphology. ANIMALS: Fifty-two healthy cats. METHODS: Cross-sectional study of the biliary tracts of healthy cats during laparoscopic ovariohysterectomy and measurement of pancreatic enzyme activity in bile. The cats were divided into groups A and B based on the ratio of the diameter of the cystic duct (CD) to the CBD. The normal ratio was 3.4. Pancreatic enzyme activity in bile was compared between the groups. RESULTS: The CBDs were straight in all cases, whereas the CDs were variably tortuous or dilated. Amylase activity in the bile (median, <100 U/L; range, <100-591 U/L) was lower than in serum in all cases, and group B, which had a CD/CBD ratio >3.4, had significantly higher amylase activity (median, 109 U/L; range, <100-591 U/L) in the bile than did group A (median, <100 U/L; range, <100-238 U/L), which had a CD/CBD ratio <3.4 (P = .0009). CONCLUSIONS AND CLINICAL IMPORTANCE: The results suggest that a dilated CD is associated with reflux of pancreatic juice. In the future, it will be necessary to examine the clinical usefulness of these findings by measuring pancreatic enzyme activity in the bile of cats with cholangitis.

Retrospective analysis of canine gallbladder contents in biliary sludge and gallbladder mucoceles.

The pathophysiology of canine gallbladder diseases, including biliary sludge, gallbladder mucoceles and gallstones, is poorly understood. This study aimed to evaluate the component of gallbladder contents and bacterial infection of the gallbladder in order to elucidate the pathophysiology of biliary sludge and gallbladder mucoceles. A total of 43 samples of canine gallbladder contents (biliary sludge, 21 and gallbladder mucoceles, 22) were subjected to component analysis by infrared spectroscopy, and the resultant infrared spectra were compared with that of swine mucin. Of the 43 samples, 41 were also evaluated by aerobic and anaerobic bacterial culture. The contents of 20 (95.2%) biliary sludge and 22 (100%) gallbladder mucocele samples exhibited similar infrared spectra as swine mucin. Although biliary sludge and gallbladder mucocele contents exhibited similar infrared spectra, one sample of biliary sludge (4.8%) was determined to be composed of proteins. The rate of bacterial infection of the gallbladder was 10.0% for biliary sludge and 14.3% for gallbladder mucoceles. Almost all of the identified bacterial species were intestinal flora. These results indicate that the principal components of gallbladder contents in both gallbladder mucoceles and biliary sludge are mucins and that both pathophysiologies exhibit low rates of bacterial infection of the gallbladder. Therefore, it is possible that gallbladder mucoceles and biliary sludge have the same pathophysiology, and, rather than being independent diseases, they could possibly represent a continuous disease. Thus, biliary sludge could be considered as the stage preceding the appearance of gallbladder mucoceles.

Neural mechanisms and personality correlates of the sunk cost effect.

The sunk cost effect, an interesting and well-known maladaptive behavior, is pervasive in real life, and thus has been studied in various disciplines, including economics, psychology, organizational behavior, politics, and biology. However, the neural mechanisms underlying the sunk cost effect have not been clearly established, nor have their association with differences in individual susceptibility to the effect. Using functional magnetic resonance imaging, we investigated neural responses induced by sunk costs along with measures of core human personality. We found that individuals who tend to adhere to social rules and regulations (who are high in measured agreeableness and conscientiousness) are more susceptible to the sunk cost effect. Furthermore, this behavioral observation was strongly mediated by insula activity during sunk cost decision-making. Tight coupling between the insula and lateral prefrontal cortex was also observed during decision-making under sunk costs. Our findings reveal how individual differences can affect decision-making under sunk costs, thereby contributing to a better understanding of the psychological and neural mechanisms of the sunk cost effect.

Global association between cortical thinning and white matter integrity reduction in schizophrenia.

Previous neuroimaging studies have revealed that both gray matter (GM) and white matter (WM) are altered in several morphological aspects in schizophrenia patients. Although several studies reported associations between GM and WM alterations in restricted regions, the existence of a global association between GM and WM pathologies is unknown. Considering the wide distribution of GM morphological changes and the profound genetic background of WM abnormalities, it would be natural to postulate a global association between pathologies of GM and WM in schizophrenia. In this investigation, we studied 35 schizophrenia patients and 35 healthy control subjects using T1-weighted magnetic resonance imaging and diffusion tensor imaging (DTI) and investigated the association between GM thickness and WM fractional anisotropy (FA) as a proxy of pathology in each tissue. To investigate cortical thickness, surface-based analysis was used. The mean cortical thickness for the whole brain was computed for each hemisphere, and group comparisons were performed. For DTI data, mean FA for the whole brain was calculated, and group comparisons were performed. Subsequently, the correlation between mean cortical thickness and mean FA was investigated. Results showed that the mean cortical thickness was significantly thinner, and the mean FA was significantly lower in schizophrenia patients. Only in the patient group the mean cortical thickness and mean FA showed significant positive correlations in both hemispheres. This correlation remained significant even after controlling for demographic and clinical variables. Thus, our results indicate that the GM and WM pathologies of schizophrenia are intertwined at the global level.

Are ambiguity aversion and ambiguity intolerance identical? A neuroeconomics investigation.

In recent years, there has been growing interest in understanding a person's reaction to ambiguous situations, and two similar constructs related to ambiguity, "ambiguity aversion" and "ambiguity intolerance," are defined in different disciplines. In the field of economic decision-making research, "ambiguity aversion" represents a preference for known risks relative to unknown risks. On the other hand, in clinical psychology, "ambiguity intolerance" describes the tendency to perceive ambiguous situations as undesirable. However, it remains unclear whether these two notions derived from different disciplines are identical or not. To clarify this issue, we combined an economic task, psychological questionnaires, and voxel-based morphometry (VBM) of structural brain magnetic resonance imaging (MRI) in a sample of healthy volunteers. The individual ambiguity aversion tendency parameter, as measured by our economic task, was negatively correlated with agreeableness scores on the self-reported version of the Revised NEO Personality Inventory. However, it was not correlated with scores of discomfort with ambiguity, one of the subscales of the Need for Closure Scale. Furthermore, the ambiguity aversion tendency parameter was negatively correlated with gray matter (GM) volume of areas in the lateral prefrontal cortex and parietal cortex, whereas ambiguity intolerance was not correlated with GM volume in any region. Our results suggest that ambiguity aversion, described in decision theory, may not necessarily be identical to ambiguity intolerance, referred to in clinical psychology. Cautious applications of decision theory to clinical neuropsychiatry are recommended.

Regional gray matter reduction correlates with subjective quality of life in schizophrenia.

Subjective quality of life (QOL) has been recognized as an important consideration in schizophrenia. Several symptoms and neurocognitive functions were shown to be correlated with subjective QOL; however its determinants are not well understood. In this study, we investigated the association between brain structural abnormalities and subjective QOL in patients with schizophrenia. Forty-five schizophrenia patients and 48 age, sex, and education-matched healthy participants underwent magnetic resonance imaging (MRI), and the Schizophrenia Quality of Life Scale (SQLS) was used to rate subjective QOL. We performed voxel-based morphometry (VBM) to investigate regional brain alterations. Relative to normal controls, schizophrenia patients exhibited gray matter reductions mainly in the frontal and temporal regions. Worse psychosocial subscale of SQLS was associated with gray matter (GM) reduction in the right dorsolateral prefrontal cortex (DLPFC), and worse motivation/energy subscale was associated with gray matter reduction in the left superior frontal sulcus, left parahippocampal gyrus, and the left inferior temporal gyrus. The correlation between DLPFC GM volume and psychosocial subscale of SQLS disappeared after controlling for severity of psychopathology, while the other correlations remained significant when controlled by demographic and clinical variables. Combining imaging techniques with psychosocial methods would help to elucidate those factors that are associated with QOL.

Thalamocortical disconnection in the orbitofrontal region associated with cortical thinning in schizophrenia.

CONTEXT: Dysfunction of the thalamocortical pathway has been proposed as a putative underlying pathology of schizophrenia. Although the mechanisms involved remain unclear, postmortem studies suggest the involvement of altered neural projections from the thalamus to layers within the prefrontal cortex. OBJECTIVES: To investigate thalamocortical connectivity in schizophrenia and to examine its possible association with cortical thinning in vivo. DESIGN: Case-control cross-sectional study. SETTING: Department of Psychiatry at Kyoto University Hospital, Japan. PATIENTS AND OTHER PARTICIPANTS: A total of 37 patients with schizophrenia and 36 age-, sex-, and education-matched healthy controls recruited from the local community underwent diffusion-weighted imaging and T1-weighted 3-dimensional magnetic resonance imaging. MAIN OUTCOME MEASURES: Probabilistic tractography was performed to investigate thalamocortical pathways. Group differences in mean fractional anisotropy (FA) values were examined in the entire thalamocortical pathway, the thalamolateral prefrontal pathway, the thalamomedial prefrontal pathway, and the thalamo-orbitofrontal pathway. Surface-based analysis was performed to investigate cortical thickness, and the correlation between FA values and cortical thickness was examined. RESULTS: The patient group exhibited reduced FA values within the right thalamo-orbitofrontal pathway (P < .05 for the 8 group comparisons of FA, Bonferroni correction). In the patient group only, the mean FA value for this pathway was positively correlated with thickness of the right frontal polar and lateral orbitofrontal cortices (P < .05, clusterwise correction). CONCLUSIONS: These results suggest that, in schizophrenia, regional thalamocortical white matter pathology is specifically associated with cortical pathology in regions where fibers connect.

Alexithymia and reduced white matter integrity in schizophrenia: a diffusion tensor imaging study on impaired emotional self-awareness.

Alexithymia is characterized by deficits in emotional self-awareness. A number of previous studies have revealed impaired emotional self-awareness in schizophrenia. Although the pathology of schizophrenia is thought to involve disrupted white matter integrity, its relationship with alexithymia remains unclear. The present study investigated associations between alexithymia and white matter integrity, to seek the neural basis of impaired emotional self-awareness in schizophrenia. Forty-four patients with schizophrenia and 44 age-, gender- and predicted IQ level-matched healthy controls underwent diffusion-weighted imaging. Alexithymia was assessed using the 20-item Toronto Alexithymia Scale (TAS-20). We applied tract-based spatial statistics to investigate the correlation between the TAS-20 total score and white matter fractional anisotropy (FA). TAS-20 scores were significantly higher in patients than in controls. In the patient group only, FA was negatively correlated with the TAS-20 total score in the corpus callosum, mostly the left part of the superior and inferior longitudinal fasciculi, the inferior occipito-frontal fasciculus, the anterior and posterior thalamic radiation, and the precuneus white matter. These results suggest that schizophrenia is associated with alexithymia, and that reduced white matter integrity within these regions constitutes an important pathology underlying impaired self-emotional awareness in schizophrenia.

Abnormal asymmetry of white matter integrity in schizophrenia revealed by voxelwise diffusion tensor imaging.

A number of magnetic resonance imaging (MRI) studies have revealed morphological cortical asymmetry in the normal human brain, and reduction or inversion of such hemispheric asymmetry has been reported in schizophrenia. On the other hand, diffusion tensor imaging (DTI) studies have reported inconsistent findings concerning abnormal asymmetry of white matter integrity in schizophrenia. Our aim was to confirm whether there is reduced or inverted asymmetry of white matter integrity in the whole brain in schizophrenia. For this study, 26 right-handed schizophrenia patients, and 32 matched healthy control subjects were investigated. Voxelwise analysis of DTI data was performed using the tract-based spatial statistics. The fractional anisotropy (FA) images were normalized and projected onto the symmetrical white matter skeleton, and the laterality index (LI) of FA, determined by 2 × (left - right)/(left + right), was calculated. The results reveal that schizophrenia patients and healthy controls showed similar patterns of overall FA asymmetries. In the group comparison, patients showed significant reduction of LI in the external capsule (EC), and posterior limb of the internal capsule (PLIC). The EC cluster revealed increased rightward asymmetry, and the PLIC cluster showed reduced leftward asymmetry. Rightward-shift of FA in the EC cluster correlated with negative symptom severity. Considering that the EC cluster includes the uncinate and inferior occipitofrontal fasciculi, which have connections to the orbitofrontal cortex, abnormal asymmetry of white matter integrity in schizophrenia may play a crucial role in the pathogenesis of schizophrenia, through the altered connectivity to the orbitofrontal cortex.

Social impairment in schizophrenia revealed by Autism-Spectrum Quotient correlated with gray matter reduction.

One of the difficulties facing schizophrenia patients is a failure to construct appropriate relationships with others in social situations. This impairment of social cognition is also found in autism-spectrum disorder (ASD). Considering such commonality between the two disorders, in this study we adopted the Autism-Spectrum Quotient (AQ) score to assess autistic traits, and explored the association between such traits and gray matter (GM) alterations of the brain in schizophrenia. Twenty schizophrenia patients and 25 healthy controls underwent structural magnetic resonance imaging (MRI), and AQ was assessed, comprising five subscales measuring different facets of autistic traits. Voxel-based morphometry (VBM) was applied to investigate the correlation between these AQ scores and regional GM alterations. Schizophrenia patients showed significantly higher scores in total AQ, and in four of the five subscales, compared to healthy controls. The total AQ score in schizophrenia showed significant negative correlation with GM volume reduction in the cortical area surrounding the left superior temporal sulcus (STS), which is considered to be important in social perception. Our findings suggest a possible neuroanatomical basis of autistic tendencies in schizophrenia.

Alexithymia and regional gray matter alterations in schizophrenia.

Alexithymia is characterized by deficits in emotional self-awareness. Although alexithymia refers to a deficit in recognizing one's own emotions, some studies have focused on the relation between alexithymia and impaired social cognition. An association between alexithymia and schizophrenia has been previously reported, but the brain structures involved remain unclear. The present study investigated associations between alexithymia and specific brain structures to determine whether these regions overlapped with key structures underlying social cognition. Twenty-one patients with schizophrenia and 24 age-, gender- and education level-matched healthy controls underwent structural magnetic resonance imaging. Alexithymia was assessed using the 20-item Toronto Alexithymia Scale (TAS-20). We applied voxel-based morphometry to investigate the correlation between TAS-20 scores and regional brain alterations. TAS-20 scores were significantly higher in patients than controls. Bilateral ventral striatum and left ventral premotor cortex volumes were negatively correlated with TAS-20 total scores in controls, while left supramarginal gyrus (SMG) volume was negatively correlated with TAS-20 total scores in patients. These results suggest that schizophrenia is associated with alexithymia, and that gray matter alterations of the left SMG constitute a key pathology underlying alexithymia in schizophrenia. This association may be related to deficits in self-other distinction, self-disturbance, and language processing in schizophrenia.

Age-related cortical thinning in schizophrenia.

Although the effects of aging on the neural correlates of schizophrenia have been researched for many years, no clear conclusion has been reached. While some studies have demonstrated progressive age-related gray matter reductions in schizophrenia, other studies have not found evidence of progression. Moreover, it remains unclear whether the influence of aging on global or regional cortical thickness differs between schizophrenia patients and healthy controls. This study aimed to confirm previous reports of reduced cortical thickness in schizophrenia, and to investigate the effects of age on global and regional cortical thickness. Eighty-three patients with schizophrenia (six first-episode patients and 77 chronic patients; age range=18-55 years) and 90 age-, gender- and education-matched healthy controls (age range=19-56 years) underwent structural magnetic resonance imaging (MRI) using a 3-Tesla scanner. Surface-based analysis was applied to assess cortical thickness in the whole brain. The patient group exhibited both global and regional cortical thinning in regions including the prefrontal and temporal cortices. The correlation between age and cortical thickness showed a similar pattern in patients and controls, both globally and regionally. These results suggest that the reduction of cortical thickness in schizophrenia might not be progressive over the course of the illness, indicating that pathological processes occur in a relatively limited period of time around the onset of illness.

Investigating association of brain volumes with intracranial capacity in schizophrenia.

Intracranial volume (ICV) is usually treated as a global or nuisance covariate in almost all volumetric studies of schizophrenia. However, validation for this analytic method has seldom been accomplished. In this study, we aimed to determine the effects of ICV on gray matter (GM) and white matter (WM) volumes. Sixty-three patients with schizophrenia and sixty normal controls were recruited; and high resolution T1 weighted images were obtained by 3T-MRI. After segmentation and normalization of the images into GM, WM, and cerebrospinal fluid (CSF), multiple regression analyses of global GM and WM volumes were performed using explanatory variables such as diagnosis, ICV, and diagnosis-ICV interaction. In addition, associations between regional GM and WM volumes with ICV were also investigated using voxel-based morphometry (VBM). No significant interaction between diagnosis and ICV was found for global GM volume, whereas interactions were detected in restricted GM areas using VBM. On the other hand, an interaction between ICV and diagnosis was found in WM not only for regional volumes, but also for global WM volume. The regression slope of global WM volumes against ICV was steeper in patients with schizophrenia than in healthy controls. These results imply that ICV should be carefully evaluated in the analyses of volumetric studies of schizophrenia, especially when analyzing WM volumes.

Rapid cycling bipolar disorder after left temporal polar damage.

The case of a 48-year-old woman with rapid cycling bipolar disorder subsequent to a traumatic brain injury is reported. Both depressive and manic episodes had an average duration of approximately 1 month, alternating without stable euthymic periods. Neuroradiological examinations revealed a circumscribed lesion in the left temporal pole. After 1 year without treatment, psychiatric intervention and pharmacotherapy was initiated. Her mood swings were successfully treated with the co-administration of valproate and lithium. Case reports of rapid cycling bipolar disorder after traumatic brain injury are very rare and this case supports the idea that temporal polar dysfunction is a candidate for the neurobiological basis of rapid cycling bipolar disorder.