An Improved Method for Collecting Breath for the Assay of Acetaldehyde

An improved method is described for the collection of breath for the subsequent assay of acetaldehyde and other volatile components. Breath is collected in a Pyrex gas-collecting tube sealed at both ends with Teflon taps. Prior to collection or assay of the samples, this tube is heated to 72 degrees C; breath is sampled for assay by piercing a rubber septum on a sideport with the needle of a similarly heated gas-tight syringe, and injected into a gas chromatograph (GC). The advantages of this system are: (1) Avoidance of the artefacts encountered in the assay of acetaldehyde in the blood; (2) suitability for sample collection at a site remote from the GC laboratory; (3) avoidance of sample loss by leakage, contamination, or partitioning into water condensed from breath; and (4) compatibility with a "nondedicated" GC lacking any special gas-collecting circuitry. A typical study of a normal human volunteer is described, demonstrating the rise and fall of the concentration of acetaldehyde and ethanol in the breath following the ingestion of an oral dose of ethanol.     

2,2',5,5'-Tetrachlorobiphenyl: isolation and identification of metabolites generated by rat liver microsomes

The in vitro metabolism of 2,2',5,5'-tetrachloro[3H]biphenyl (TCB) by control and phenobarbital-induced rat liver microsomes has been investigated. Phenobarbital induction was found to significantly increase (30-fold) the NADPH-dependent, microsomal metabolism of TCB above that observed with control microscomes. The metabolites generated by microsomes of phenobarbital-induced rats were separated by Sephadex LH-20 and gas-liquid chromatography (GLC) and were subsequently characterized by infrared and mass spectral (MS) analyses and techniques of catalytic dechlorination with GLC/MS comparison to biphenylol standards. The major metablite, representing 90% of all metabolic products, was identified as 3-hydroxy-TCB. 3,4-Dihydro-3,4-dihydroxy-TCB was identified as a minor metabolite (5%), and trace amounts of two chromatographically and spectrally distinct dihydroxy-TCB's (4% and 1%) were also found. This in vitro metabolic profile is consistent with that found in vivo and suggests a mechanism of TCB metabolism incorporating both direct hydroxylation and an arene oxide intermediate.     

The "air enema" in acute colitis

The plain abdominal radiograph is an important investigation in acute colitis, but may fail to demonstrate the state of the colon owing to a lack of intracolonic gas. The extent of the colitis can be demonstrated by introducing air directly into the large bowel; the air also provides sufficient contrast to distinguish a granular from an ulcerated mucosa. The "air enema" may be used as an alternative to an unprepared barium enema. Its accuracy has been established by comparison with an unprepared barium enema in 10 patients with acute colitis.     

The effects of scopolamine on retrieval from semantic memory

The effects of two doses of scopolamine (0.6 and 1.2 mg p.o.) on retrieval from semantic memory in normal young volunteers were examined using tests of verbal fluency and categorization latency. A visual contrast sensitivity test, which has previously shown a scopolamine-induced impairment at these doses (Broks et al., 1988), was also administered. In agreement with the work of Dunne (1990) and others, no evidence for a scopolamine deficit in semantic retrieval was found; in fact scopolamine improved letter fluency. However, scopolamine did produce the expected decrease in visual contrast sensitivity. The doses of scopolamine used here have also been shown to impair learning and attention (Broks et al., 1988). It is possible that earlier studies which found a scopolamine deficit on semantic retrieval, did so because they used elderly subjects and/or large drug doses.     

Energy expenditure and protein synthesis rates in an animal model of cancer cachexia

Food intake and energy expenditure of cachectic tumour bearing mice were measured during the course of weight loss. Four weeks after implantation of the MAC-16 tumour the body weight was reduced by 20%, there was no significant reduction in food intake, and body composition analysis revealed that both body fat and protein mass were decreased. Oxygen consumption and carbon dioxide production were measured over a 24h period both before and at weekly intervals after tumour implantation. There was a gradual increase in the rates of both oxygen consumption and carbon dioxide production per gram body weight. Similarly, energy expenditure per gram body weight was increased during the 3rd (11%) and 4th (23%) weeks. In contrast, the food intake per gram body weight was unchanged during the first three weeks and increased by only 8% during the 4th week. Despite the development of cachexia, rates of protein synthesis in the liver, heart, kidney and skeletal muscle were the same four weeks after tumour implantation as those in non-tumour bearing mice. Thus, in this murine model of cancer cachexia a negative energy balance resulted from failure of food intake to compensate for increased energy demands. These findings point to the unique pattern of metabolic alterations which occur in different models of cancer cachexia.     

Mathematical Ability and Lateral Asymmetry

The hypothesis that special ability in mathematics is associated with a reduction in bias to dextral preference and skill was examined in several samples of students and in 97 male and 27 female teachers of mathematics, mainly in Universities and Polytechnics. The maths students and maths teachers differed from controls, both general and academic, in the direction predicted and several comparisons were statistically significant. Differences were in most cases clearer for males than females.An analysis of the findings in relation to the right shift (RS) theory of handedness (Annett, 1972, Annett, 1978) suggests that the incidence of left preference and skill is slightly raised in mathematicians not because of any intrinsic advantage of left preference but rather because extreme bias to the right, as expected in those carrying a hypothesised rs++ genotype, is disadvantageous for mathematical thinking. If the role of mathematics can be regarded as one of developing languages to describe those aspects of human experience which otherwise could be understood only in visuo-spatial images, it can be seen to require a coordination of those aspects of human intelligence which have been distinguished as depending differentially on the left and right cerebral hemispheres. The present findings suggest that this process might be impeded by a double dose of a gene which promotes left hemisphere language specialisation.     

Chronic fluphenazine treatment modifies circadian rhythms of neurotransmitter receptor binding in rat brain

Summary Binding to rat brain- and-adrenergic, muscarinic cholinergic, dopamine and opiate receptors was measured at 4-hour intervals throughout a 24-hour period in animals, chronically treated with fluphenazine, and in controls. Drug treatment significantly changed characteristics of the circadian rhythms in all 5 receptors. In the presence of the drug the 24-hour mean binding to the dopamine receptor was decreased; to the other 4 receptors it was increased. Moreover, there were changes in the timing of the maximal receptor binding (phase-position) and in the amplitude of the rhythms. These results extend previous studies, showing that chronic neuroleptic treatment not only affects the dopamine receptors, but also other neurotransmitter receptors, profoundly modifying their temporal organisation.     

An attempt to objectify the therapeutic process: a working model.

On the basis of their observations in daily psychoanalytic work the authors developed five objective criteria for "bad" analytic hours. These criteria involve affect, intellectualization, isolation, lack of feedback, and dissatisfaction. The authors developed a formulation to help them preconsciously recognize the presence of these factors during therapeutic work and found that it was helpful in turning a potentially bad hour into a productive one.