The effect of lorazepam on memory and event-related potentials in heavy and light social drinkers

To investigate the effects of heavy social drinking on sober cognitive processing, event-related potentials were recorded from 13 heavy social drinkers and 13 light social drinkers in the presence and absence of a pharmacological challenge (i.e., lorazepam). Event-related potentials were elicited by a task reuqiring continuous recognition memory for visually presented words. The heavy social drinkers exhibited shorter P2 latencies than the light in the task) versus “new” words. Lorazepam increased motor reaction time to correctly identified old words and produced a deficit in recognition memory only in the light social drinkers. Light social drinkers had an increased P300 latency anda larger P300 amplitude to new words in the lorazepam treatment. The differences in cognitive functioning evident between heavy and light social drinkers were reflected in event-related potential deviations and appear to indicate a tolerance in heavy social drinkers to the effects of lorazepam.     

Dermatoses in five related female carriers of X-linked chronic granulomatous disease

Eight female members of a family with X-linked chronic granulomatous disease were identified. Five were shown to be carriers of the disease gene. Each of these female carriers of the gene had a history of skin eruptions. The identification of the carrier state is important as genetic counselling should be offered and the prenatal diagnosis of this disorder is possible.     

A possible role for mono(ADP-ribosyl)transferase in the signalling pathway mediating neutrophil chemotaxis

1 Mono(ADP-ribosyl)transferase activity has been identified on the external surface of human polymorphonuclear neutrophil leucocytes (PMNs). The enzyme is released from the plasma membrane by phosphoinositide-specific phospholipase C, suggesting a glycosylphosphatidylinositol (GPI) linkage of the enzyme to the plasma membrane. Partial sequence of cDNA encoding the enzyme suggests that it is identical to the GPI-linked mono(ADP-ribosyl)transferase identified previously on human skeletal muscle.
2 A panel of inhibitors of mono(ADP-ribosyl)transferase (including vitamins K₁ and K₃, novobiocin and nicotinamide) showed a rank order of inhibitory potency similar to that described for other mono(ADP-ribosyl)transferases. Furthermore, the mono(ADP-ribosyl)ation of agmatine was inhibited also by diethylamino(benzylidineamino)guanidine (DEA-BAG), another substrate of the enzyme related structurally to arginine.
3 There was a close linear correlation between the I C ₅₀ values for inhibition of mono(ADP-ribosyl)ation of agmatine by DEA-BAG or the enzyme inhibitors and their I C ₅₀ values for inhibition of receptor-dependent polymerization of cytoskeletal actin and chemotaxis.
4 These results suggest a role for mono(ADP-ribosyl)transferase in the transduction pathway involved in receptor-dependent re-alignment of the cytoskeleton during neutrophil chemotaxis.     

Patient management problems Issues of validity

Patient management problems (PMP) are being used in medical examinations with increasing frequency despite evidence which throws doubt on their validity as measures of clinical competence. This study investigated the construct validity of a PMP constructed in both written and interview formats. Each test was administered to groups of students of different seniorities and to two groups of Docotor, interns and post-interns. The pattern of scores for the different groups was not that expected of a valid test of competence. The most competent groups (the postinterns) generally scored less well on the calculated indices than the senior students and interns. These findings were similar for both formats of the test so cueing was not thought to be the major factor. It appears that the scoring system is at fault.
A comparison of performance on the written and interview (uncued) formats showed that many more options were chosen by all groups tested on the written PMP.
It was concluded that written PMPs cannot yet be regarded as a valid simulation of clinical performance. Although content validity is high this does not appear to be so for construct validity or concurrent validity.     

Sweet potato revisited

In Britain, the sweet potato is a new and exotic addition to the variety of vegetables on offer in retail outlets. However, elsewhere, especially in tropical developing countries, it has been a safeguard against hunger for centuries. The good nutritional qualities and range of sensory characteristics of the sweet potato are now being re-explored on an international level with a view to development and promotion of the crop and its processed food products in both developed and developing countries.     

Human enolase isozymes: electrophoretic and biochemical evidence for three loci

1. Four major enolase isozymes have been identified in human tissues and are referred to as L, M, 'intermediate' and 'fast'. The M isozyme is the major form found in skeletal muscle and heart extracts and the L isozyme the major form found in extracts of liver and most other tissues. The 'intermediate' and 'fast' isozymes are most active in brain but are observed as weak components in most other tissues including heart but are not seen in skeletal muscle. It was observed that during fetal development of heart and skeletal muscle the L form declines in activity while the M form increases in activity. 2. The kinetic properties, heat stabilities and molecular sizes of the main enolase isozymes have been compared. Although the isozymes share many features in common, the 'fast' isozyme is more stable when subjected to heat treatment than either the L or M isozymes. Further, the 'fast' isozyme retains its dimeric structure and activity in the absence of magnesium ions while the L and M isozymes dissociate and lose activity. The 'intermediate' isozyme has properties which are intermediate to those of the L and 'fast' isozymes. 3. The 'intermediate' isozyme can be partially dissociated to equal quantities of L and 'fast' isozymes by storage at room temperature or by freezing and thawing in the presence of 2 M-NaCl. Conversely, mixtures of L with 'fast' and M with 'fast' give rise to an 'intermediate' isozyme after freezing and thawing. 4. Evidence derived from this study has led to the suggestion that three separate gene loci are involved in the determination of human enolase. It is proposed that one of these, ENO1, determines the L isozyme which is the homodimer alphaalpha; another locus, ENO2, determines the 'fast' isozyme which is the homodiner betabeta; and the third locus, ENO3, determines the M isozyme which is the homodimer gammagamma. The 'intermediate' isozyme seen as a strong component in brain and as a weak component in most other tissues is thought to be the heterodimer alphabeta. In heart however it is probably mainly betagamma.