Yasuhiro Sato

Bio: Yasuhiro Sato is an academic researcher from Tohoku University. The author has contributed to research in topics: Capsule endoscopy & Prefrontal cortex. The author has an hindex of 5, co-authored 14 publications receiving 330 citations.

Neural basis of impaired cognitive flexibility in patients with anorexia nervosa.

Abstract: Background Impaired cognitive flexibility in anorexia nervosa (AN) causes clinical problems and makes the disease hard to treat, but its neural basis has yet to be fully elucidated. The purpose of this study was to evaluate the brain activity of individuals with AN while performing a task requiring cognitive flexibility on the Wisconsin Card Sorting Test (WCST), which is one of the most frequently used neurocognitive measures of cognitive flexibility and problem-solving ability. Methods Participants were 15 female AN patients and 15 age- and intelligence quotient-matched healthy control women. Participants completed the WCST while their brain activity was measured by functional magnetic resonance imaging during the task. Brain activation in response to set shifting error feedback and the correlation between such brain activity and set shifting performance were analyzed. Results The correct rate on the WCST was significantly poorer for AN patients than for controls. Patients showed poorer activity in the right ventrolateral prefrontal cortex and bilateral parahippocampal cortex on set shifting than controls. Controls showed a positive correlation between correct rate and ventrolateral prefrontal activity in response to set shifting whereas patients did not. Conclusion These findings suggest dysfunction of the ventrolateral prefrontal cortex and parahippocampal cortex as a cause of impaired cognitive flexibility in AN patients.

Gastrointestinal symptoms and disorders in patients with eating disorders

Abstract: The two most clinically serious eating disorders are anorexia nervosa and bulimia nervosa. A drive for thinness and fear of fatness lead patients with anorexia nervosa either to restrict their food intake or binge-eat then purge (through self-induced vomiting and/or laxative abuse) to reduce their body weight to much less than the normal range. A drive for thinness leads patients with bulimia nervosa to binge-eat then purge but fail to reduce their body weight. Patients with eating disorders present with various gastrointestinal disturbances such as postprandial fullness, abdominal distention, abdominal pain, gastric distension, and early satiety, with altered esophageal motility sometimes seen in patients with anorexia nervosa. Other common conditions noted in patients with eating disorders are postprandial distress syndrome, superior mesenteric artery syndrome, irritable bowel syndrome, and functional constipation. Binge eating may cause acute gastric dilatation and gastric perforation, while self-induced vomiting can lead to dental caries, salivary gland enlargement, gastroesophageal reflux disease, and electrolyte imbalance. Laxative abuse can cause dehydration and electrolyte imbalance. Vomiting and/or laxative abuse can cause hypokalemia, which carries a risk of fatal arrhythmia. Careful assessment and intensive treatment of patients with eating disorders is needed because gastrointestinal symptoms/disorders can progress to a critical condition.

A randomized, double-blinded, placebo-controlled, multicenter trial, healing effect of rebamipide in patients with low-dose aspirin and/or non-steroidal anti-inflammatory drug induced small bowel injury

Abstract: Background It is not clear what kind of drug is appropriate to heal NSAID-induced enteropathy. Several reports showed the preventive effect of prostaglandin analogue or inducer using healthy subjects who took NSAIDs. However there was no report for healing effect and for patients. The aim of this study was to evaluate the healing effect of rebamipide in patients with NSAIDs-induced enteropathy. In addition, we evaluated for nutritional parameter.

Research Review: What we have learned about the causes of eating disorders – a synthesis of sociocultural, psychological, and biological research

Abstract: Background Eating disorders are severe psychiatric disorders with a complex etiology involving transactions among sociocultural, psychological, and biological influences. Most research and reviews, however, focus on only one level of analysis. To address this gap, we provide a qualitative review and summary using an integrative biopsychosocial approach. Methods We selected variables for which there were available data using integrative methodologies (e.g., twin studies, gene-environment interactions) and/or data at the biological and behavioral level (e.g., neuroimaging). Factors that met these inclusion criteria were idealization of thinness, negative emotionality, perfectionism, negative urgency, inhibitory control, cognitive inflexibility, serotonin, dopamine, ovarian hormones. Literature searches were conducted using PubMed. Variables were classified as risk factors or correlates of eating disorder diagnoses and disordered eating symptoms using Kraemer et al.'s (1997) criteria. Findings Sociocultural idealization of thinness variables (media exposure, pressures for thinness, thin-ideal internalization, thinness expectancies) and personality traits (negative emotionality, perfectionism, negative urgency) attained ‘risk status’ for eating disorders and/or disordered eating symptoms. Other factors were identified as correlates of eating pathology or were not classified given limited data. Effect sizes for risk factors and correlates were generally small-to-moderate in magnitude. Conclusions Multiple biopsychosocial influences are implicated in eating disorders and/or disordered eating symptoms and several can now be considered established risk factors. Data suggest that psychological and environmental factors interact with and influence the expression of genetic risk to cause eating pathology. Additional studies that examine risk variables across multiple levels of analysis and that consider specific transactional processes amongst variables are needed to further elucidate the intersection of sociocultural, psychological, and biological influences on eating disorders.

Eating Disorders in Children and Adolescents: State of the Art Review

Abstract: Despite their high prevalence, associated morbidity and mortality, and available treatment options, eating disorders (EDs) continue to be underdiagnosed by pediatric professionals. Many adolescents go untreated, do not recover, or reach only partial recovery. Higher rates of EDs are seen now in younger children, boys, and minority groups; EDs are increasingly recognized in patients with previous histories of obesity. Medical complications are common in both full and subthreshold EDs and affect every organ system. No single cause of EDs has emerged, although neurobiological and genetic predispositions are emerging as important. Recent treatment paradigms acknowledge that they are not caused by families or chosen by patients. EDs present differently in pediatric populations, and providers should have a high index of suspicion using new Diagnostic and Statistical Manual, 5th edition diagnostic criteria because early intervention can affect prognosis. Outpatient family-based treatment focused on weight restoration, reducing blame, and empowering caregivers has emerged as particularly effective; cognitive behavioral therapy, individual therapy, and higher levels of care may also be appropriate. Pharmacotherapy is useful in specific contexts. Full weight restoration is critical, often involves high-calorie diets, and must allow for continued growth and development; weight maintenance is typically inappropriate in pediatric populations. Physical, nutritional, behavioral, and psychological health are all metrics of a full recovery, and pediatric EDs have a good prognosis with appropriate care. ED prevention efforts should work toward aligning with families and understanding the impact of antiobesity efforts. Primary care providers can be key players in treatment success.

Irritable bowel syndrome: A microbiome-gut-brain axis disorder?

Abstract: Irritable bowel syndrome (IBS) is an extremely prevalent but poorly understood gastrointestinal disorder. Consequently, there are no clear diagnostic markers to help diagnose the disorder and treatment options are limited to management of the symptoms. The concept of a dysregulated gut-brain axis has been adopted as a suitable model for the disorder. The gut microbiome may play an important role in the onset and exacerbation of symptoms in the disorder and has been extensively studied in this context. Although a causal role cannot yet be inferred from the clinical studies which have attempted to characterise the gut microbiota in IBS, they do confirm alterations in both community stability and diversity. Moreover, it has been reliably demonstrated that manipulation of the microbiota can influence the key symptoms, including abdominal pain and bowel habit, and other prominent features of IBS. A variety of strategies have been taken to study these interactions, including probiotics, antibiotics, faecal transplantations and the use of germ-free animals. There are clear mechanisms through which the microbiota can produce these effects, both humoral and neural. Taken together, these findings firmly establish the microbiota as a critical node in the gut-brain axis and one which is amenable to therapeutic interventions.