Electrical stimulation of the dorsal raphe nucleus as a discriminative stimulus: generalization to (+/-)-DOI

Electrical stimulation of the dorsal raphe nucleus of Sprague-Dawley rats was used as the cue for discrimination using a taste aversion paradigm. Rats were trained to associate saccharin drinking during electrical stimulation of the dorsal raphe nucleus with LiCl injection after the session as the aversive unconditioned stimulus. In sessions without stimulation, rats were allowed to consume saccharin and received a saline injection after the session. Suppression of saccharin consumption during electrical stimulation was learned within 12 trials. Rats trained in the reverse discrimination, i.e., sessions with no electrical stimulation paired with LiCl injection, showed a similar learning curve. Animals injected prior to the session with the hallucinogenic 5-HT2 agonist (+/-)-DOI associated DOI with electrical stimulation of the dorsal raphe nucleus. Thus, animals may be trained to discriminate electrical stimulation of the dorsal raphe nucleus. Furthermore, animals generalize from activation of 5-HT2 receptors to electrical stimulation of the dorsal raphe nucleus.

Observer variation and discriminatory value of biopsy features in inflammatory bowel disease

If skilled histopathologists disagree over the same biopsy specimen, at least one must have an incorrect interpretation. Thus, disagreement is associated with, although not the cause of, diagnostic error. The present study aimed to determine the magnitude of variation among 10 observers with a special interest in gastrointestinal histopathology. They independently interpreted the same biopsy specimens for morphological features which may discriminate between patients with Crohn's disease and ulcerative colitis and normal subjects. Thirty of 41 features had agreement measures significantly better than expected by chance (p < 0.05). The range of agreement in the 45 observer pairs over the final diagnosis was 65-76%. There was good agreement in discriminating between normal slides and those showing confirmed inflammatory bowel disease. For normal slides, however, the term nonspecific inflammation was often applied and without any consistency. In addition, true Crohn's disease slides were often and consistently thought to be ulcerative colitis. Having identified 11 important discriminatory morphological features, two multiple regression analyses were then carried out to produce a scoring system for inflammatory bowel disease. These results suggest there is considerable room for improvement in the reliability of colonic biopsy specimen interpretation and that this could probably be achieved using more exact definitions of morphological features and diseases.

Health visitors' use of health education material

An Oxford study reveals wide variations in health visitors' use of printed health education materials with clients. Their choice appears dictated largely by personal preference and judgement, and by lack of availability of suitable materials. MARY DIXON and RALPH JOHNSON argue that standards and guidelines are needed on which, how and why such leaflets are used.

Psychometric assessment of the Allen Barriers to Treatment Instrument

The purpose of this study was to determine the psychometric properties of the Allen Barriers to Treatment Instrument (ABTI). Internal consistency reliability was assessed as well as five types of validity: face, content, criterion-related, convergent, and construct. A panel of experts was used to assess face and content validity of the ABTI; a two-group comparison method was used to evaluate criterion-related validity; qualitative analysis of responses to open-ended questions on the ABTI provided information about convergence; and item-to-total correlations of scores along with factor analysis was used to evaluate construct validity. Results showed strong evidence of the reliability and validity of the ABTI.

Injuries to elite gymnasts over 10 yr

This retrospective study of 42 male and 74 female elite (artistic) gymnasts at the Australian Institute of Sport (AIS) reviews all the injuries reported between 1982 and 1991 (inclusive). The injuries were categorized according to type of injury and their specific anatomical distribution. The study also analyzes the incidence of stress fractures in the gymnasts and the prevalence of spondylolysis. Although it is noted from the literature that gymnastics can be a hazardous sport, this study demonstrates an absence of catastrophic injuries and a low number of severe injuries.

Microsatellite polymorphisms for chromosome 5 bands q11.2-q13.3

The genes for spinal muscular atrophy (SMA) and a possible subtype of schizophrenia (SCZD1) have been mapped to chromosome 5q11.2-q13.3. DNA markers have been mapped to 5q11.2-q13.3 using a hybrid cell line deleted for this region [Gilliam et al., Genomics 1989;5:940-944]. Genomic lambda clones for these markers facilitated the identification of highly polymorphic microsatellites. A total of ten microsatellites were identified and sequenced. Of these, seven were found to be polymorphic. Four had polymorphism information content values > 0.7. New polymorphic microsatellites were sequenced for D5S76, D5S125, D5S39, D5S127 and HEX-B. Two-point and multipoint analysis in non-CEPH pedigrees confirmed that the microsatellites were in tight linkage with each other. These new microsatellites will increase the efficiency of linkage analysis for these disorders.

Physical localization of 70 polymorphic markers to human chromosome 5 by fluorescence in situ hybridization

We used fluorescence in situ hybridization (FISH) to prepare a cytogenetic framework map of 21 polymorphic markers that had been used previously to construct a genetic linkage anchor map of chromosome 5. In addition, we localized 49 other markers that have been genotyped on CEPH families. This study demonstrates that FISH can be used to confirm genetic linkage data, and that it can provide a means of determining the cytogenetic locations and relative order of markers whose order could not be assigned by genetic linkage analysis alone. The cytogenetic map prepared by FISH may help to identify probes of interest for regional mapping studies.

Hypnotic susceptibility and verbal automaticity: automatic and strategic processing differences in the Stroop color-naming task

The original hypothesis of Dixon, Brunet, and Laurence (1990) that highly hypnotizable (HH) subjects process words more automatically than do low hypnotizable (LH) subjects was retested in a paradigm that separated strategic from automatic processes in the Stroop color-naming task. The words red and blue preceded a color patch that was red or blue. Subjects were told that the word predicted the opposite color 75% of the time. Automatic and strategic processes were assessed by varying the interstimulus interval (ISI) between the word and the color patch. Both HH and LH subjects showed significant strategic effects (faster incongruent-trial, color-naming reaction times than congruent-trial reaction times at ISIs over 400 ms), but only HH subjects showed significant automaticity (significantly faster congruent-trial reaction times than incongruent-trial reaction times at 16.7 ms, the lowest ISI).

Hypnotic susceptibility and verbal automaticity: Automatic and strategic processing differences in the Stroop color-naming task

The original hypothesis of Dixon, Brunet, and Laurence (1990) that highly hypnotizable (HH) subjects process words more automatically than do low hypnotizable (LH) subjects was retested in a paradigm that separated strategic from automatic processes in the Stroop color-naming task. The words red and blue preceded a color patch that was red or blue. Subjects were told that the word predicted the opposite color 75% of the time. Automatic and strategic processes were assessed by varying the interstimulus interval (ISI) between the word and the color patch. Both HH and LH subjects showed significant strategic effects (faster incongruent-trial, color-naming reaction times than congruent-trial reaction times at ISIs over 400 ms), but only HH subjects showed significant automaticity (significantly faster congruent-trial reaction times than incongruent-trial reaction times at 16.7 ms, the lowest ISI).

Linkage disequilibrium between two highly polymorphic microsatellites

The PCR was used to amplify genomic DNA from two microsatellite (dC-dA)n.(dG-dT)n sequences found to be present in the same chromosome 5 genomic clone. Analysis of the haplotype frequencies of these two interspersed repeat sequences in individuals showed strong allelic association or linkage disequilibrium. Six alleles were found for p599 (CA)n with a PIC value of 0.71 and 8 alleles were seen for lambda 599 (CA)n with a PIC value of 0.74. The two microsatellites are separated by approximately 7 kb. Analysis of the length variations for the two microsatellites showed that they were positively correlated, a finding that has no obvious explanation. The strong linkage disequilibrium found demonstrates stability during evolution for these novel markers. Therefore they should be powerful new tools for studying genetic drift and admixture of populations. Furthermore, disequilibrium data from microsatellites can be used in the fine mapping and cloning of disease genes.

A PstI polymorphism in the human coagulation factor V (F5) gene

Images