Effects of information and reward on stimulus-preceding negativity prior to feedback stimuli

The purpose of the present study was to investigate the effects of informational and motivational level of feedback stimuli on the stimulus-preceding negativity (SPN). In the time estimation task, in which a visual stimulus was presented 3 s after a voluntary movement, (a) the information level (high information and low information) and (b) the motivation level (reward and no-reward) for feedback stimuli were manipulated. Under the high-information condition, subjects received feedback information about (1) correctness (correct or incorrect), (2) direction of error (under- or overestimate), and (3) degree of accuracy (accurate or less accurate) of their time estimation. In the low-information condition, however, they received information about the correctness only. In the reward condition, they received a monetary reward for accurate time estimations but received nothing in the no-reward condition. The results demonstrated a significant interaction of information by motivation level, showing that the SPN amplitude under the reward/high-information was larger than that in the no-reward/high-information condition. The results are discussed in terms of emotional anticipation, taking into consideration the result of self-report that subjects felt to be more motivated when they received precise information.     

α2-Macroglobulin secretion enhanced in rat hepatocytes by partially characterized factor from Kupffer cells

Isolated rat Kupffer cells produced a factor which stimulated the synthesis of ₂-macroglobulin (2M) in primary cultured rat hepatocytes. Although Kupffer cells placed in culture produced the factor without stimulation by lipopolysaccharide (LPS), the LPS-stimulated cells produced larger amounts of the factor. On the other hand, the production of the factor was inhibited by addition of actinomycin D. The induction of2M synthesis by cultured hepatocytes was enhanced in the presence of dexamethasone (Dex), in that hepatic synthesis of2M increased by addition of the factor alone and with Dex 1.5 and three- to four-fold, respectively. The factor was nondialyzable and stable at 60°C for 30 min. When the factor was fractionated using the molecular sieve method, the activity recovered in the fraction had a molecular weight of over 30,000.     

Giant inflammatory polyposis of the descending colon associated with a Crohn's disease-like colitis

A case of giant inflammatory polyposis associated with a localized inflammatory bowel disease of the descending colon in a 49-year-old man is presented. Lower abdominal distension rapidly appeared without any previous history of gastrointestinal disease. Two months later, he underwent a left hemicolectomy. Postoperative recovery was complete and he remains in good health more than 2 years later. The resected colon showed a giant and bizarre polyposis measuring up to 12 cm in length and 2 cm in height and covering the entire circumference of the colon. The polyposis consisted of narrow worm- or noodle-like polyps that bridged over the irregularly shaped ulcers, which sometimes extended into muscularis propria. Although longitudinal ulcers or scars, stricture, and a cobble-stone appearance were not observed, transmural inflammation and deep fissures were found in the interpolypoid area. From these findings, this case seems to be more similar to Crohn's disease than other inflammatory bowel diseases.     

Cytomegalovirus infections following umbilical cord blood transplantation using reduced intensity conditioning regimens for adult patients.

Cytomegalovirus (CMV) infection is a major complication after allogeneic hematopoietic stem cell transplantation (Allo-HSCT); however, we have little information on the clinical features of CMV reactivation after cord blood transplantation using reduced-intensity regimens (RI-CBT) for adults. We reviewed medical records of 140 patients who underwent RI-CBT at Toranomon Hospital between January 2002 and March 2005. All the patients were monitored for CMV-antigenemia weekly, and, if turned positive, received preemptive foscarnet or ganciclovir. Seventy-seven patients developed positive antigenemia at a median onset of day 35 (range, 4-92) after transplant. Median of the maximal number of CMV pp65-positive cells per 50,000 cells was 22 (range, 1-1806). CMV disease developed in 22 patients on a median of day 35 (range, 15-106); 21 had enterocolitis and 1 had adrenalitis. CMV antigenemia had not been detected in 2 patients, when CMV disease was diagnosed. CMV disease was successfully treated using ganciclovir or foscarnet in 14 patients. The other 8 patients died without improvement of CMV disease. In multivariate analysis, grade II-IV acute graft-versus-host disease was a risk factor of CMV disease (relative risk 3.48, 95% confidential interval 1.47-8.23). CMV reactivation and disease develop early after RI-CBT. CMV enterocolitis may be a common complication after RI-CBT.     

Age-dependent change in activities of lysosomal enzymes in rat brain

The age-dependent change in activities of seven lysosomal enzymes (cathepsin D, β-glucuronidase, acid phosphatase, acid/alkaline DNases and acid/alkaline RNases) was studied in four brain regions (cerebrum, hippocampus, pons and cerebellum) of Wistar rats. The activity of cathepsin D was significantly increased with aging in the four regions. The age-dependent change in activities of acid and alkaline DNases showed the characteristic regional difference, and the ratio of acid to alkaline DNases was increased with aging in all regions. Acid RNase showed the lowest activity in 18-month-old rats, and alkaline RNase activity was decreased with aging. The activity of β-glucuronidase was higher in 2-month-old rats in all of the regions studied. Acid phophatase showed no significant age-dependent change except in pons. The study demonstrated that all of the lysosomal enzyme activities do not change in parallel with aging, and that the age-dependent change showed the characteristic regional difference.     

Cyclic AMP-dependent Cl− secretion induced by thromboxane A2 in isolated human colon

Increased release of thromboxane A₂ (TXA₂) has been shown to be involved in inflammatory bowel diseases. In the present study, we have investigated the effect of a stable TXA₂ analogue (STA₂) on the electrical parameters in isolated human colonic mucosa. In the human mucosa set between Ussing chambers, STA₂ stimulated Cl⁻ secretion in a concentration-dependent manner with an EC₅₀ of 0.06 μ m . The STA₂-induced Cl⁻ secretion was significantly inhibited by ONO-3708 (10 μ m ), a specific TXA₂ receptor antagonist. The effect of STA₂ (0.3 μ m ) was independent of the colonic segment from which the tissue was obtained, from caecum to rectum. Chromanol 293B, an inhibitor of the cAMP-dependent KvLQT1 channel, attenuated the STA₂-induced Cl⁻ secretion in the human colonic mucosa (IC₅₀ value 1.18 μ m ). We found that KvLQT1 mRNA and protein were expressed in all the tested segments of the human colon. The STA₂-induced Cl⁻ secretion was significantly inhibited by 8-bromo-2'-monobutyryladenosine-3',5'-cyclic monophosphorothioate (50 μ m ), a membrane-permeant cAMP antagonist. STA₂ (0.3 μ m ) significantly increased the intracellular cAMP levels and the short-circuit current via TXA₂ receptor in a human colonic cell line. These results suggest that the TXA₂-induced Cl⁻ secretion in the colon is mediated via the cAMP pathway in addition to the Ca²⁺–calmodulin pathway which was previously reported.     

Structural basis for distinct roles of Lys63- and Lys48-linked polyubiquitin chains

Ubiquitination, a modification in which single or multiple ubiquitin molecules are attached to a protein, serves as a signalling function that controls a wide variety of cellular processes. To date, two major forms of polyubiquitin chain have been functionally characterized, in which the isopeptide bond linkages involve Lys48 or Lys63. Lys48-linked polyubiquitin tagging is mostly used to target proteins for degradation by the proteasome, whereas Lys63-linked polyubiquitination has been linked to numerous cellular events that do not rely on degradative signalling via the proteasome. Apparently linkage-specific conformations of polyubiquitin chains are important for these cellular functions, but the structural bases distinguishing Lys48- and Lys63-linked chains remain elusive. Here, we report NMR and small-angle X-ray scattering (SAXS) studies on the intersubunit interfaces and conformations of Lys63- and Lys48-linked di- and tetraubiquitin chains. Our results indicate that, in marked contrast to Lys48-linked chains, Lys63-linked chains are elongated molecules with no stable non-covalent intersubunit interfaces and thus adopt a radically different conformation from that of Lys48-linked chains.     

Polymerization of 2-vinyl-1,3-dioxolane

When 2-vinyl-1,3-dioxolane was treated at low temperature (?78 or ?130°C.) with cationic catalysts, oily or semi-solid polymer was produced. The result of alkaline hydrolysis showed that the polymeric product contained ester units whose amount was about 2 to 15 mole-% of the total units. The remaining part of the polymer consisted of units containing the dioxolane ring. In the alkaline alcoholysis of the polymer with ethanol ethyl δ-hydroxyvalerate was formed. These findings indicate that in the low temperature cationic polymerization of 2-vinyl-1,3-dioxolane the ester unit, ? O(CH₂)₄CO? , is formed in addition to the unit of vinyl polymerization. A mechanism for the formation of the ester unit has been proposed, in which the process of hydride-shift is followed by ring-opening of the resulting carbonium ion species of dioxolane.