FREE RADICALS FORMED IN HYDROTREATED COAL LIQUID AND INFLUENCE OF OXYGEN

The behavior of radicals formed in hydrotreated coal liquid with heat treatment and the influence of oxygen have been investigated by electron spin resonance (e.s.r.) spectroscopy. A set of e.s.r. spectral lines identified as phenalenyl radical appears from 50^°C as the oil is heated in argon atmosphere. The radical concentration is enhanced with temperature, reaches a maximum between 130 and 150^°C and then decreases at higher temperatures. The radical is very stable even at 200^°C for the sample hydrotreated under mild condition, whereas the radical in the sample treated under severe conditions disappears drastically from 150^°C. When oxygen is introduced in the oil, the radical is converted into semiquinone and/or aryloxy radicals and stable molecules. The treatment in the presence of oxygen at higher temperatures is considered to accompany the formation of other aryloxy radicals by the reaction of aromatic hydrocarbons and oxygen.     

Synthesis of (+/-)-cassumunins A and B, new curcuminoid antioxidants having protective activity of the living cell against oxidative damage

A chemical synthesis of cassumunins A (1) and B (2), natural curcuminoid antioxidants, was developed. The synthesis was started from o-vanillin and after nine reaction steps resulted in 20% and 26% overall yields of 1 and 2, respectively. The synthetic cassumunins showed stronger protective activity than curcumin against oxidative cell death induced by hydrogen peroxide in a rat thymocyte system.     

Triazolam-induced modulation of muscarinic acetylcholine receptor in living brain slices as revealed by a new positron-based imaging technique

The effect of triazolam, a potent benzodiazepine (BZ) agonist, on muscarinic acetylcholinergic receptor (mAChR) binding was investigated in living brain slices by use of a novel positron-based imaging technique. Fresh rat brain slices were incubated with [11C]N-methyl-4-piperidylbenzilate ([11C]NMPB), a mAChR antagonist, in oxygenated Krebs-Ringer solution at 37 degrees C. During incubation, time-resolved imaging of [11C]NMPB binding in the slices was constructed on the storage phosphor screens. Addition of triazolam (1 microM) plus muscimol (30 microM), a GABA(A) receptor agonist, to the incubation mixture decreased the specific binding of [11C]NMPB. Ro15-1788, a BZ receptor antagonist, prevented this effect, indicating that the effect was exerted through the GABA(A)/BZ receptor complex. These results demonstrated that stimulation of the GABA(A)/BZ receptor lowers the affinity of the mAChR for its ligand, which may underlie the BZ-induced amnesia, a serious clinical side effect of BZ. No such effect in the P2-fraction instead implies that the integrity of the neuronal cells and/or their environment is prerequisite for the modulation of mAChR by GABA(A)/BZ stimulation.     

Increased plasma levels of substance P and disturbed water excretion in patients with liver cirrhosis

We describe a surgical technique for replacing the hip joint capsule using synthetic mesh after oncological resections of the proximal femur that resulted in gross intraoperative instability of the prosthetic reconstruction. The results of its use in 13 patients, 6 of whom also had pelvic resections, are described. These patients were selected from a total group of 88 patients undergoing proximal femoral replacement, 75 of whom did not require capsular replacement (none of these 75 patients have experienced dislocation). In the group requiring capsular reconstruction, 1 of 4 patients with bipolar hemiarthroplasty and 4 of 9 patients with total hip replacements experienced dislocation after operation. Of the dislocated total hip replacements, 1 remains chronically dislocated, and 3 were successfully stabilized by open reduction with further capsular augmentation. Given that the resections involved removal of most of the soft tissues stabilizing the hip joint, we believe that the technique of capsular reconstruction is useful in this difficult group of patients.     

The significance of the morphology of the dorsal pancreatic artery in determining the presence of the accessory right hepatic artery passing behind the portal vein

The dorsal pancreatic artery (DP) and an accessory right hepatic artery (AcRH) passing behind the portal vein were investigated in 98 Japanese specimens. The dorsal pancreatic artery was identified in 87 specimens (88.8%). This artery has been found to yield the following 6 branches: (1) an inferior pancreatic artery (left branch, 83.9%); (2) a right branch-1 that serves as the prepancreatic arcade in front of the pancreas (77.0%); (3) an uncinate branch that distributes to the uncinate process (60.9%); (4) a head branch that distributes from the dorsal side of the pancreas to the head of the pancreas (newly defined in the present study, 60.9%); (5) a right branch-4 that distributes superior to the dorsal part of the pancreatic neck (39.1%); and (6) a right branch-5 that communicates with the posterior pancreaticoduodenal arcade (21.8%). In some cases, the above six branches are formed separately, i.e., two (18.4%) or three (5.7%) dorsal pancreatic arteries are present. The parent artery of the DP was the superior mesenteric artery (SM; 55.0%), accounting for 45.0% of the entire celiac trunk. An accessory right hepatic artery was identified in 18 specimens (18.4%). In cases where the AcRH originated from the entire celiac trunk (5 specimens, 27.8%), it always formed a common trunk with the DP. On the other hand, when the AcRH derived from the SM (13 specimens, 72.2%), it formed a common trunk with the DP 6 of the specimens (33.3%), independent branching was observed in 6 specimens (33.3%). And a common trunk with the inferior pancreaticoduodenal artery was observed in one specimen (5.6%). The dorsal pancreatic artery was considered to supply not only the AcRH but also other pathways that form more complicated variations such as an accessory middle colic artery.     

Regio- and stereoselective synthesis of carbocyclic 2'',3''-dideoxy-3''-fluoro nucleosides as potential antiviral agents

OBJECTIVE: To determine the prevalence of the symptom of urinary incontinence during athletic endeavors among a group of nulliparous, elite college varsity female athletes. METHODS: All women currently participating in varsity athletics at a large state university were asked to fill out a questionnaire about the occurrence of urinary incontinence while participating in their sport and during activities of daily life. One hundred forty-four of 156 eligible women (92%) responded. RESULTS: The mean age was 19.9 years, and all women were nulliparous. Overall, 40 athletes (28%) reported urine loss while participating in their sport. The proportions in different sports were: gymnastics 67%, basketball 66%, tennis 50%, field hockey 42%, track 29%, swimming 10%, volleyball 9%, softball 6%, and golf 0%. Two-thirds of the women who noted urine loss during athletics were incontinent more often than rarely. There were no statistically significant relations between incontinence and amenorrhea, weight, hormonal therapy, or duration of athletic activity. Activities most likely to provoke incontinence included jumping, high-impact landings, and running. Forty percent and 17% of the women first noted incontinence during their sport while in high school and junior high school, respectively. CONCLUSIONS: Incontinence during physical stresses is common in young, highly fit, nulliparous women. This suggests that there is a continence threshold which, when exceeded, can result in urine loss, even in the absence of known risk factors for incontinence.     

Modes in curved step-index optical fibres

By using parabolic, instead of circular, cylindrical co-ordinates the field distributions of the natural modes of curved step-index fibres can be described completely, yet simply. The mode caustics corresponding to the geometrical guiding limit of the equivalent rays of curved fibre can be clearly demonstrated. Near-field mode patterns and caustics obtained experimentally are in excellent agreement with the theory.