Motor disorders of the oesophagus in gastro-oesophageal reflux.

Mechanisms of gastro-oesophageal reflux were studied by oesophageal manometry and pH monitoring in 33 children: nine controls, 15 with gastro-oesophageal reflux alone, and nine with reflux oesophagitis. A total of 122 episodes of reflux were analysed in detail: 82 (67%) were synchronous with swallowing and 40 (33%) asynchronous. Infants with trivial symptoms had gastro-oesophageal reflux synchronous with swallowing, whereas those with serious symptoms had slower acid clearance and asynchronous reflux. There were significant differences in lower oesophageal sphincter pressure and amplitude of oesophageal contractions between controls and patients with both gastro-oesophageal reflux and reflux oesophagitis. In reflux oesophagitis there was a decrease in lower oesophageal sphincter pressure and the contractions had a bizarre waveform suggesting a neuropathic process.     

Studies of enuresis VIII. Detrusor and sphincter instability caused by overactivity of integral voiding reflexes

Ninety-one children with nocturnal enuresis or enuresis plus daytime urgency incontinence were studied by cystometry. Seventy-two per cent of the girls and 62 per cent of the boys had evidence of bladder instability. Sixty-eight children in whom abnormalities were found on preliminary voiding urodynamics or voiding cystourethrography also underwent calibration and endoscopic examination under anesthesia. An atropine-suppression test was also performed preoperatively in some children with a markedly unstable bladder demonstrated on preoperative cystometry. In the majority of children tested suppression of bladder instability with atropine was demonstrable. Voluntary detrusor sphincter dyssynergia was demonstrated in a majority of the children with daytime urgency incontinence. Sixty-five per cent of the boys and 81 per cent of the girls were treated for urethral obstructive lesions suspected to be of functional urodynamic significance. Postoperative cystometry showed marked improvement in bladder stability in 57 per cent of the girls and 63 per cent of the boys treated for suspected urethral obstructive pathology. The anticholinergic suppression test was found to have no significant predictive value relative to the cause or surgical curability of bladder instability. The pathophysiologic significance of overactivity of integral voiding reflexes 6 through 11 is described.     

Experimental and modeling investigation of metal release from metal-spiked sediments

In sediments that contain iron monosulfide, cadmium, nickel, lead, zinc, and silver(I) form insoluble metal sulfides that lower the metal ion activity in the sediment-pore water system, thereby reducing toxicity. However, metal sulfides are susceptible to oxidation by molecular oxygen resulting in metal solubilization. To better understand the sources and sinks of metal sulfides in sediments, iron monsulfide-rich freshwater sediments were spiked with cadmium, nickel, lead, zinc, or silver(I) and placed into cylindrical cores with an overlying layer of oxygen-saturated water. Measurements of the dissolved metal concentration in the overlying water were made as a function of time and the vertical profiles of acid-volatile sulfide (AVS) and simultaneously extracted metal (SEM) were measured after 150 d. A one-dimensional reactive and transport model has been employed to help elucidate processes controlling the fate of metals in sediments. The model incorporates metal-sulfide formation, metal-sulfide oxidation, and metal partitioning onto sediment organic carbon and iron oxyhydroxide to simulate the vertical transport of metals throughout the sediment core.     

Induction of Bacteriocins from Clostridium perfringens by Treatment with Mitomycin C

Six of ten bacteriocinogenic strains of Clostridium perfringens were inducible by treating the cultures with mitomycin C. Induction did not occur in the continued presence of mitomycin C but only when excess mitomycin C was removed. Cell death was associated with induction of bacteriocin.     

Comparative Study of Ten Bacteriocins of Clostridium perfringens

Bacteriocins of Clostridium perfringens were prepared by ammonium sulfate precipitation of supernatant broth from 10 bacteriocinogenic strains. These bacteriocins were compared with respect to their ability to produce spheroplasts in a sensitive indicator strain; their inducibility; sensitivity to pH, proteolytic enzymes, and boiling; and their effect on macromolecular synthesis. Two bacteriocins were stable over a wide range of pH values and resisted boiling, and three bacteriocins were resistant to trypsin. Five bacteriocins shut down DNA, RNA, and protein synthesis; three bacteriocins had varying effects on DNA and RNA synthesis; and two bacteriocins had little effect on macromolecular synthesis. Antiserum prepared against one bacteriocin highly neutralized three bacteriocins with partial neutralization of five others; two bacteriocins were unaffected. Mutant strains selected for resistance to bacteriocin 28 also demonstrated coresistance to two other closely related bacteriocins and partial resistance to five others.     

Incontinence of urine due to instability of micturition reflexes: Part I. Detrusor reflex instability

Micturition reflex instability may result from malfunction of the detrusor reflex or instability of the pudendal nucleus which innervates the pelvic floor muscles and external sphincter. Detrusor instability is the result of sacral micturition reflex center (SMRC) hyperexcitability. This may be caused by underinhibition or overfacilitation of the SMRC, and there are both central and peripheral causes of each. Detrusor hypertrophy may invoke chronic overactivity of the detrusodetrusor facilitative reflex causing SMRC overfacilitation. Similarly, distal urethral stricture and/or chronic urethritis causing chronic overactivity of the urethrodetrusor facilitative reflex is a common cause of SMRC overfacilitation. Pathologic relaxation and weakness of the striated muscles of the pelvic floor and perineum resulting in underactivity of the perineodetrusor inhibitory reflex, is a common cause of SMRC underinhibition. In adult women these factors often coexist. Each may predispose to stress-induced detrusor instability and are often seen in association with, or are confused with, true stress incontinence. The distinguishing characteristics of detrusor hypertonicity and detrusor hyperreflexia are reviewed, and the various mechanisms of pseudostress incontinence and of urgency incontinence are discussed in detail.