Relation between the alternating monomer unit sequence and the cis and trans linkage configurations at the cyclic maleic anhydride units in the copolymers of styrene and maleic anhydride prepared in carbon tetrachloride

The monomer unit triad sequence distribution and the cis/trans linkage configurations at the cyclic maleic anhydride (MA) units in the copolymers of styrene (ST) and MA prepared in CCl₄ with AIBN at 50°C were quantitatively determined by ¹³C DEPT NMR spectroscopy. So much as 61 % of the linkages at the MA units were found to be in cis configuration, which was considered to be formed by a participation of the 1:1 electron donor-acceptor complex formed between ST and MA in the propagation step. The mole fraction of the cis configuration was found to be proportional to the mole fraction of alternating triad sequences when the monomer unit sequences approach to be completely alternating. This supported the proposal that, in alternating and semi-alternating copolymerizations, the alternating sequences were formed mainly by the addition of the complex. The equilibrium constant of the complexation in CCl₄ at 23°C was determined to be 0,21 L/mol.     

FLAGELLUM OF THE MICROORGANISM OF RAT-BITE FEVER

The work of previous investigators was confirmed in that the microorganism of rat-bite fever was found to have flagella which are clearly visible by dark-field illumination and which can be stained. The best staining is obtained with alkalinized Akashi solution, which is a modification of Giemsa''s solution; the vapor of osmic acid gives the best fixation. The number of demonstrable flagella seems to vary with the technique. Sometimes many slender flagella unite into one large one or one large flagellum divides into several smaller ones. It may be concluded that commonly many slender flagella occur at the ends and that these may unite into one or several large flagella. In the living microorganism the flagella appear to be spiral. Their form in fixed preparations depends upon the method employed. Some long forms have flagella arising at the middle of the body; this seems to indicate that division is transverse and not longitudinal as generally believed. The rigid body, the signs of transverse division, and multiple flagella seem to distinguish the forms reported here from spirochetes and indicate that they are spirilla.     

The prevention of experimental cholesterol gallstones by ileectomy in mice

After a lithogenic diet containing 0.5 per cent cholesterol and 0.25 per cent sodium cholate was fed to a group of normal Crj-ICR male mice for 10 days, cholesterol gallstones developed. No formation of gallstones occurred, however, in a group of mice from which 20 cms of terminal ileum had been removed prior to the feeding of the lithogenic diet. The biliary concentrations of cholesterol, phospholipids and bile acids were markedly lower in the ileectomized mice, with the decrease in cholesterol concentration being most significant. On the other hand, fecal excretion of sterols and bile acids increased in the ileectomized mice. The pool size of bile acids increased after the feeding of the lithogenic diet, but ileectomy decreased the pool size in mice fed the ordinary or lithogenic diets. The biliary concentration of cholic acid increased after the feeding of the lithogenic diet, but decreased with ileectomy. The biliary concentration and fecal excretion of deoxycholic acid markedly increased, while those of β-muricholic acid and its secondary bile acids, ω-muricholic acid and hyodeoxycholic acid, decreased. The increase in plasma and liver cholesterol levels after the feeding of the lithogenic diet was prevented by ileectomy. These data suggest that ileectomy prevents the formation of cholesterol gallstones after the feeding of a lithogenic diet due to a decrease in cholic acid absorption.     

Osteoarthritis in shoulders with traumatic anterior instability: preoperative survey using radiography and computed tomography

The purposes of this report are to determine the incidence of preoperative osteoarthritis in shoulders with traumatic anterior instability and to detect the factors leading to its development. The radiographs and computed tomograms of shoulders in 282 patients with unilateral instability and without previous surgery, whose age was younger than 40 years and who had no possibility of nontraumatic secondary osteoarthritis, were examined by use of a simplified modification of Samilson and Prieto's criteria. Osteoarthritis was found in 32 joints (11.3%) (mild in 30 and moderate in 2) on the radiographs. Computed tomography (CT) revealed arthritic changes in 88 shoulders (31.2%), including all 32 radiographically osteoarthritic joints. The marginal spur of the humeral head initially occurred in the anteroinferior aspect and mainly extended downward. The total number of dislocations and/or subluxations and frequency of dislocation and/or subluxation of 32 radiologically osteoarthritic joints were significantly larger and higher, respectively, than those of 194 non-osteoarthritic joints (P < .02). The total number of dislocations and/or subluxations (P < .01) and the number of subluxations (P < .05) were significantly different between osteoarthritic joints and nonarthritic joints classified by CT findings. The rate detected by CT was higher than those of any other previous radiographic survey that may have underestimated the incidence rate. Most postoperative osteoarthritis cases recognized on radiographs in short-term or midterm follow-up studies are assumed to be preoperatively generated.     

Diurnal fluctuation of time perception under 30-h sustained wakefulness

Previous studies have reported that time perception in humans fluctuates over a 24-h period. Behavioral changes seem to affect human time perception, so that the fluctuation in human time perception may be the result of such changes due to self-determined activities. Recently, we carried out a study in which a healthy human cohort was asked to perform simultaneously loaded cognitive tasks under controlled conditions, and found that time perception decreased linearly from morning to evening. In addition, the variations in time perception were not a consequence of behavioral changes. It remains to be elucidated whether diurnal variations in time perception are a consequence of circadian rhythm or of some homeostatic changes that are attributable to accumulated wake time. The effects of circadian rhythm on time perception were investigated in eight healthy young male volunteers by conducting 10-s time production tasks under 30-h constant-routine conditions. Core body temperature and serum melatonin and cortisol levels were measured during the course of the study. Produced time exhibited a diurnal variation and was strongly correlated with circadian variations in core body temperature and serum melatonin levels. These results suggest that human short-term time perception is under the influence of the circadian pacemaker.     

Prospective study of fever and pneumonia after flexible fiberoptic bronchoscopy in older people

OBJECTIVES: To assess the frequency of fever and pneumonia after fiberoptic bronchoscopy (FOB) in older people and to evaluate increased risk for these two adverse events with increasing age. DESIGN: Prospective study. SETTING: University hospital system. PARTICIPANTS: Three hundred fifty-eight patients, with 165 (46.1%) patients aged 70 and older, undergoing bronchoscopy. MEASUREMENTS: Indications, abnormal bronchoscopic findings, sampling procedures, final diagnosis, and fever and pneumonia after bronchoscopy. RESULTS: With regard to the indication for bronchoscopy and abnormal bronchoscopic findings, there was no statistical difference between elderly patients (> or =70) and younger patients (<70). Procedures such as forceps biopsy, brushing, and curetting were not performed more often in elderly patients, although final diagnosis of lung cancer was significantly more common in the elderly group (P=.002). The overall incidence of fever after FOB was 6.7%, and that of pneumonia after FOB was 5.6%. The patients aged 70 and older had an incidence of fever after FOB of 3.6% and an incidence of pneumonia of 4.2%, which were not higher than those in patients younger than 70. CONCLUSION: Increasing age is not associated with increasing fever and pneumonia after FOB, and chronological age should not be considered a limiting factor in the decision of whether to perform FOB when it is clinically indicated.