Deficit of state-dependent risk attitude modulation in gambling disorder.

Gambling disorder (GD) is often considered as a problem of trait-like risk preference. However, the symptoms of GD cannot be fully understood by this trait view. In the present study, we hypothesized that GD patients also had problem with a flexible control of risk attitude (state-dependent strategy optimization), and aimed to investigate the mechanisms underlying abnormal risk-taking of GD. To address this issue, we tested GD patients without comorbidity (GD group: n=21) and age-matched healthy control participants (HC group: n=29) in a multi-step gambling task, in which participants needed to clear 'block quota' (required units to clear a block, 1000-7000 units) in 20 choices, and conducted a task-functional magnetic resonance imaging (fMRI) experiment. Behavioral analysis indeed revealed a less flexible risk-attitude change in the GD group; the GD group failed to avoid risky choice in a specific quota range (low-quota condition), in which risky strategy was not optimal to solve the quota. Accordingly, fMRI analysis highlighted diminished functioning of the dorsolateral prefrontal cortex (dlPFC), which has been heavily implicated in cognitive flexibility. To our knowledge, the present study provided the first empirical evidence of a deficit of state-dependent strategy optimization in GD. Focusing on flexible control of risk attitude under quota may contribute to a better understanding of the psychopathology of GDs.

Free radicals and superoxide dismutase in blood of patients with Alzheimer's disease and vascular dementia.

We measured hydroxyl radical (.OH) levels in blood, superoxide dismutase (SOD) activity in red blood cells (RBC) relative to both total protein (RBC-SOD/P) and Cu,Zn-SOD protein (RBC-SOD/SOD), SOD activity in plasma (plasma-SOD), and Cu,Zn-SOD protein relative to total RBC protein (Cu,Zn-SOD/P) in 22 patients with probable dementia of the Alzheimer type (DAT group, mean age 74.8+/-9.4 years), 16 with probable vascular dementia (VAD group, mean age 76.9+/-6.7 years) and 19 non-demented controls (control group, mean age 73.5+/-6.2 years). Levels of .OH in the DAT and VAD groups were significantly (P<0.01 and P<0.001, respectively) higher, whereas the values of RBC-SOD/P and RBC-SOD/SOD in these two groups (both P<0.001) and Cu,Zn-SOD/P in the DAT group (P<0.001) were significantly lower than the corresponding control values. Members of the VAD group with risk factors for stroke (RF+ group) showed significantly higher .OH levels than members of the VAD group without risk factors (RF- group; P<0.01) and the control group (P<0.001). RBC-SOD/P and RBC-SOD/SOD values in the RF+ group were significantly (both P<0.01) lower than the corresponding control values. There were no significant differences among the VAD, RF+ and control groups with respect to Cu,Zn-SOD/P values, or between the RF- and control groups for any measured parameter. We conclude that oxidative stress plays a role in the brain damage seen in both DAT and VAD, and that the causes of decreased SOD activity in RBC differ between DAT and VAD patients.

Cloning and sequence analysis of a gene (aly PG) encoding poly(alpha-L-guluronate)lyase from Corynebacterium sp. strain ALY-1.

The aly PG gene, coding for a poly alpha-l-guluronate lyase (PG lyase) of Corynebacterium strain ALY-1, was cloned and sequenced. The gene consists of 768 bp encoding a signal peptide of 32 amino acids and a mature protein of 224 amino acids. Two disulfide bond cross-linkages were found to be formed between Cys-4 and Cys-51 and between Cys-200 and Cys-206 in the native PG lyase molecule. The deduced amino acid sequence of the Corynebacterium sp. aly PG gene exhibited 29% homology toward that of the Klebsiella pneumoniae, subsp. aerogenes aly A gene, with two conserved regions (the amino acid sequences from Y-102 to M-110 and from Y-221 to Q-229).

Delirium in elderly patients admitted to a psychiatric hospital: causative factors and treatment.

We studied the causes and treatments of delirium in 43 patients admitted to the geriatric-psychiatric ward of a hospital in Japan. Patients studied were divided into three groups according to the type of factor responsible for their delirium. We termed these causal factors precipitating, facilitating and predisposing factors. Twenty-one patients exhibited precipitating factors, the most common of which were overmedication and poisoning. Almost all these cases were treated with psychotropic drugs. Facilitating factors were judged responsible in nine cases. In six of these, admission to a hospital was thought to be the facilitating factor. Thirteen patients who had only predisposing factors were treated with psychotropic drugs while 27% of patients without precipitating factors were successfully treated for delirium without the use of such drugs.

Can we predict burnout severity from empathy-related brain activity?

Empathy cultivates deeper interpersonal relationships and is important for socialization. However, frequent exposure to emotionally-demanding situations may put people at risk for burnout. Burnout has become a pervasive problem among medical professionals because occupational burnout may be highly sensitive to empathy levels. To better understand empathy-induced burnout among medical professionals, exploring the relationship between burnout severity and strength of empathy-related brain activity may be key. However, to our knowledge, this relationship has not yet been explored. We studied the relationship between self-reported burnout severity scores and psychological measures of empathic disposition, emotional dissonance and alexithymia in medical professionals to test two contradictory hypotheses: Burnout is explained by (1) 'compassion fatigue'; that is, individuals become emotionally over involved; and (2) 'emotional dissonance'; that is, a gap between felt and expressed emotion, together with reduced emotional regulation. Then, we tested whether increased or decreased empathy-related brain activity measured by fMRI was associated with burnout severity scores and psychological measures. The results showed that burnout severity of medical professionals is explained by 'reduced' empathy-related brain activity. Moreover, this reduced brain activity is correlated with stronger emotional dissonance and alexithymia scores and also greater empathic disposition. We speculate that reduced emotion recognition (that is, alexithymia) might potentially link with stronger emotional dissonance and greater burnout severity alongside empathy-related brain activity. In this view, greater empathic disposition in individuals with higher burnout levels might be due to greater difficulty identifying their own emotional reactions. Our study sheds new light on the ability to predict empathy-induced burnout.

Relationship between oxidative stress and apoE phenotype in Alzheimer's disease.

OBJECTIVE: To investigate the relationship between oxidative stress and apoE phenotype in dementia of Alzheimer type (DAT). MATERIAL AND METHODS: Hydroxyl radical content in blood, superoxide dismutase (SOD) activity in red blood cells (RBC) and plasma, Cu,Zn-SOD protein content in RBC, and apoE phenotype were determined in 24 DAT patients and 25 controls. RESULTS: DAT patients with the apoE4 phenotype showed higher hydroxyl radical levels than DAT patients without the apoE4 phenotype or controls. SOD activities and Cu,Zn-SOD protein levels in RBC of DAT patients with and without the apoE4 phenotype showed no significant differences, but values in both patient groups were lower than in controls. The apoE4 phenotype was more prevalent in DAT patients than in controls. DAT patients with the apoE4 phenotype were younger at disease onset than DAT patients without the apoE4 phenotype. CONCLUSION: Our findings suggest that apoE4 and SOD individually influence oxidative stress in DAT.

Effect of Intralipid-infusion on erythrocyte membrane in rabbits.

Through Intralipid infusion in rabbits, the phospholipids derived from Intralipid were incorporated into erythrocytes, although Intralipid is mainly composed of triglycerides. This is supported by the increase in oleic acid and the compensatory decrease in linoleic acid of the phospholipids in the erythrocyte membrane, corresponding to the content of linoleic acid in the phospholipids from Intralipid. The excess phospholipid rendered the membrane more fluid, probably by overwhelming the rigidifying effect of the increased cholesterol content. Furthermore, the shape of erythrocytes was changed from biconcave to spur, dose dependently. The morphological alterations in erythrocyte membranes could not be completely elucidated by the changes in lipid. These results suggested that the alteration in lipid metabolism in Intralipid-infused rabbits caused various effects on the erythrocyte membrane, through the elevation of triglyceride, cholesterol, and phospholipid contents in plasma.

Extracellular poly(alpha-L-guluronate)lyase from Corynebacterium sp.: purification, characteristics, and conformational properties.

Extracellular alginate lyase was purified from the culture supernatant of Corynebacterium sp. isolated from the sewage of a sea tangle processing factory in order to elucidate the structure-function relationship of alginate lyase. The electrophoretically homogeneous enzyme was shown to have a molecular mass of 27 kDa by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and by gel filtration, with an isoelectric point of 7.3. The molecular mass from amino acid analysis was 28.644 kDa. The optimal pH and temperature for the enzyme reaction were around 7.0 and 55 degrees C, respectively. Metal compounds such as MnCl2 and NiCl2 increased the enzyme activity. The enzyme was identified as the endolytic poly(alpha-L-guluronate)lyase, which was active on poly(alpha-L-1,4-guluronate) and caused a rapid decrease in the viscosity of alginate solution. Measurement of the far-UV circular dichroic spectrum of the enzyme molecule gave a spectrum with a deep trough at 215 nm accompanied by a shallow one at around 237 nm, and with a high peak at 197 nm and a much lower one at 230 nm. This spectrum was most likely to be that of the beta-form of the enzyme molecule and resembled poly(beta-D-mannuronate)lyase from Turbo cornutus (wreath shell) and poly(alpha-L-guluronate)lyase from Vibrio sp. (marine bacterium). The near-UV circular dichroic spectrum was characteristic for aromatic amino acid residues. In the presence of 6 M urea, these spectra changed drastically in the near-UV and a little in the far-UV with the disappearance of the enzyme activity. Removal of the denaturant in the enzyme solution by dialysis restored both the activity and inherent circular dichroic spectra. The beta-sheets observed in alginate lyases as the major ordered structure seem to be a common conformation for the lyases.

Secondary tethered cord syndrome in spinal dysraphism.

Secondary tethered cord syndrome following initial repair for spinal dysraphism is an important area of interest. In this study, 32 cases with spinal dysraphism in the lumbosacral region were enrolled, in whom radical repair with autologous material had been carried out in the early stage soon after birth. During the follow-up period of up to 19 years 10 months, surgery was considered to be indicated in 2 of the 8 lipomeningocele cases and in 6 of the 24 meningocele and meningomyelocele cases, because of the presence of tethered cord syndrome 4-19 years after the primary operation. In all 8 of these cases, MR imaging demonstrated tethered spinal cord in the form of low conus medullaris. In 6 of the 8 operated cases surgery was followed by improvement of the spinal neurological deterioration. According to our experience, early untethering for secondary tethered cord syndrome is essential. In addition, since the complications of Silastic duraplasty at untethering were all minor and the operative outcome was satisfactory, the use of silicone rubber sheeting as a dural substitute might be recommended to prevent adhesion of the spinal cord.

Use of alpha-secondary isotope effects in nucleophile-promoted reactions of pyrimidine derivatives; evidence for transient 5,6-dihydropyrimidine intermediates.

alpha-Secondary isotope effect provides a useful tool for detection of transient 5,6-dihydropyrimidine intermediates which have been indirectly implicated in a number of chemical and enzymic conversions of pyrimidine heterocycles. The method involves the use of kinetic secondary alpha-hydrogen isotope effects which are expected to accompany sp2 to sp3 rehybridization of C-6 of the pyrimidine ring if they occur prior to or at the rate determining step. Thus, using 6-tritiated pyrimidines, and measurement of the isotopic ratio of reactant and products, kT/kH values of 1.15 or greater would be indicative of rehybridization. Using this method, we have studied the inhibition of thymidylate synthetase by 5-fluorodeoxyuridylate and 5-nitro-deoxyuridylate as well as the chemical and enzymic dehalogenation of 5-bromodeoxyuridine and 5-bromodeoxyuridylate. Large secondary isotope effects observed in all of these reactions provided strong evidence for the formation of 5,6-dihydropyrimidine intermediates.