Evaluation of an enzymic procedure for the measurement of acetaminophen.

We evaluated a new method for measurement of acetaminophen. From acetaminophen, acetate and p-aminophenol are enzymically produced, and the latter product is determined colorimetrically by reaction with o-cresol and ammoniacal copper sulfate. The method is rapid and precise, and results compare well with those by spectrophotometric and liquid-chromatographic techniques.

Simultaneous recording of myoelectrical activity and resistance from the human colon.

A system used to record myoelectrical activity from the rectosigmoid colon has been modified so that a continuous recording of electrical resistance is obtained simultaneously. Normal subjects, patients with diverticular disease and patients with the irritable colon syndrome have been studied by this method. There were variations in resistance in the form of waves for 74.

Effects of luminance gradient reversal on complex cells in cat striate cortex.

We have examined the responsiveness of various classes of complex cells in the cat's striate cortex to stimuli comprising bars aligned with segments of opposite luminance contrast. In all cases, a short segment of opposite polarity depressed, without abolishing, the bar response; within the length summation zone, the response to the bar in the presence of longer segments matched the length summation characteristics of each cell, depressed by a constant amount. The results could not be accounted for purely on the basis of convergent input from simple cells, whose behaviour to comparable stimuli has previously been reported (Hammond and MacKay 1981a).

Activation of monocytes by portal serum and its relationship to immunoglobulin, immune complex and endotoxin content.

To investigate the possibility that a "spillover effect" of substances from the portal vein into the systemic circulation accounts for the abnormal monocyte function in patients with liver disease, we have incubated human peripheral blood monocytes with paired specimens of portal and systemic serum from humans and rabbits. Monocytes incubated with portal serum released more of a lysosomal enzyme, N-acetyl-B-glucosaminidase, than those incubated with systemic serum (p less than 0.05).

Dependence of apparent blood lead half-life on the length of previous lead exposure in humans.

The expected relationship between the apparent half-life of blood lead (PbB) and the length of previous exposure is compared with the observed relationship in a group of workers on strike from a primary smelter where they had been employed for from a few months to ten years. Within this group, the apparent PbB half-life was positively correlated both with pre-strike PbB and with length of exposure to lead. It is likely that the dependence of apparent half-life on pre-strike PbB is primarily a reflection of interindividual differences in lead kinetics in these men.

Social skills training and cognitive restructuring with sexual unassertiveness in women.

From those responding to a newspaper advertisement, 29 female subjects were placed in one of four treatment groups aimed at overcoming sexual unassertiveness. The four groups were: Social Skills Training (SST); Cognitive Restructuring (CR); a combined SST and CR group; and a nondirective placebo discussion group. All treatment groups received four two-hour treatment sessions over four weeks.

On the sensitivity of complex cells in feline striate cortex to relative motion.

Responses of superficial-layer, texture-sensitive complex cells in cat striate cortex to relative motion between an oriented bar stimulus and its textured background were recorded. Some cells responded best to motion in one particular direction across the receptive field of the cell, irrespective of whether the bar and background moved simultaneously in the same (in-phase) or opposite (antiphase) directions. Others showed a clear preference for either in-phase or antiphase relative motion, irrespective of direction of motion across the receptive field.

Effects of bile acids on human colonic motor function in vitro.

The effect of bile acid perfusion on colonic motor function in vitro has been studied. It was found that bile acid perfusion and carbachol perfusion had no effect on the frequency or incidence of slow wave activity. However, the secondary bile acid deoxycholic acid (15 mmol/l) was shown to cause a statistically significant increase in percentage motility of the isolated colon (control 24.

Identification of Bacteroides gingivalis by fluorescent antibody staining.

Reactivity with the conjugates to the 4 serogroups A, B, C and C-1 of the former taxon Bacteroides melaninogenicus and with antisera to B. gingivalis and to oral strains of B. melaninogenicus subsp.

Measurement of the 5-hydroxyindoleacetic acid/creatinine ration in the urine of patients with coeliac disease.

Urinary excretion of 5-hydroxyindoleacetic acid and creatinine has been measured in 8-hour collections from adult patients with coeliac disease, and results have been compared with a group of healthy adult controls. Results were expressed as 5-HIAA/creatinine and significantly higher values of this ratio were found in patients with coeliac disease. Measurement of this ratio is a non-invasive technique which is useful in selecting patients with suspected coeliac disease for further investigation.

Renal reabsorption and secretion of delta-aminolevulinic acid in the rat.

Renal mechanisms for handling delta-aminolevulinic acid (ALA) were investigated in control and lead-exposed rats infused with ALA at a range of rates which produced plasma ALA as high as 2380 ng/mL. The presence of both reabsorption and secretion mechanisms was demonstrated. Reabsorption is the more efficient of the two mechanisms at low plasma ALA concentrations, and masks secretion in this range.

Modulatory influences of moving textured backgrounds on responsiveness of simple cells in feline striate cortex.

1. The modulatory influences of synchronously moving textured backgrounds on responsiveness to optimally oriented moving bar stimuli were investigated in 107 simple cells, with incidental observations on four complex cells, recorded in the lightly anaesthetized feline striate cortex.2.

Faecal bile acids and the irritable colon syndrome.

Faecal bile acid excretion and rectosigmoid myoelectrical activity were measured on three separate occasions over a 12-month period in 21 patients with the irritable colon syndrome. The results were compared with those of a group of normal subjects. Deoxycholic acid excretion was statistically significantly lower in patients with the irritable colon syndrome.

Non-stationarity of ocular dominance in cat striate cortex.

Interocular relationships, based on monocular directional tuning curves derived simultaneously for bar and for texture motion interleaved, are described for complex cells in the lightly-anaesthetised feline striate cortex. The results confirm earlier reports of stimulus-dependent differences in ocular dominance (Hammond 1979a, b) and demonstrate that "ocular-dominance" may be time-dependent and influenced by secondary stimulus characteristics including velocity of motion. Temporal and apparently spontaneous shifts in ocular dominance may take place other than in parallel for different classes of stimuli and may even occur simultaneously but in opposite directions.

Serum antibodies to oral Bacteroides asaccharolyticus (Bacteroides gingivalis): relationship to age and periondontal disease.

An enzyme-linked immunosorbent assay microplate method was used for measuring levels of antibody specific for the oral serotype of Bacteroides asaccharolyticus (Bacteroides gingivalis) in serum samples obtained from umbilical cords, infants, children, periodontally normal adults, and edentulous adults. Serum from patients with various periodontal diseases, including adult periodontitis, localized juvenile periodontitis, generalized juvenile periodontitis, post-localized juvenile periodontitis, and acute necrotizing ulcerative gingivitis, were also studied. A positive correlation between increase in age and increase in both prevalence and level of specific antibody in the G, A, and M classes of immunoglobulins was observed.

Simultaneous determination of directional tuning of complex cells in cat striate cortex for bar and for texture motion.

A method is described for the simultaneous determination of directional tuning of cat striate cortical complex cells for two dissimilar stimuli. Reliable pairs of tuning curves for typically four round-the-clock sequences of the two interleaved stimuli (direction stepped by 10 degrees) can be derived in approximately 10 min, including on-line plotting of data. Large numbers of comparisons are thus possible, including the evaluation of long-term fluctuations in cortical responsiveness.

Influence of velocity on directional tuning of complex cells in cat striate cortex for texture motion.

The influences of velocity on texture motion and bar motion were compared in complex cells from cat's striate cortex. Velocity preference and bandwidth were invariably higher for texture motion than for bar motion. Bar tuning profiles were essentially velocity-invariant; texture tuning profiles were unimodal at low velocity, increasingly bimodal at higher velocities, with depressed sensitivity in directions optimal for bar stimuli.

Effect of bile acid perfusion on colonic motor function in patients with the irritable colon syndrome.

A study was performed to determine the effect of bile acid perfusion on motility in the sigmoid colon of patients with the irritable colon syndrome compared with normal subjects. Deoxycholic acid (15 mM) statistically significantly increased motility in normal subjects (control 25.0 +/- 6.

An assessment of anorectal motility in the management of adult megacolon.

Anorectal motility measurements have been performed on 19 patients with adult megacolon and the results compared with 12 normal subjects. Adult Hirschsprung's disease (4 patients) was recognized by the absence of anal canal inhibition on rectal distension (normal mean inhibition 21.9 +/- 2.

Occupational exposure to lead: effects on renal function.

Although nephrotoxicity is common following exposure to lead, the dose-response relationship in adults with occupational exposure is not well understood because information is lacking on early nephrotoxic effects. By the time serum urea nitrogen and creatinine levels are elevated, renal damage may be advanced and not fully reversible. Detailed investigations of renal glomerular and tubular function were performed in six adults with occupational exposure to lead.