The Characterization of Oxotremorine-Induced Hypothermic Response in the Rat

Abstract: Oxotremorine is a muscarinic receptor agonist that induces a variety of physiological and behavioural effects including hypothermia in mice. These effects are antagonized dose-dependently by classical anticholinergic compounds such as atropine. Although the oxotremorine-induced hypothermic response has been demonstrated in mice, few studies of the effects of this muscarinic agonist have been made in the rat. The following studies were made in male Sprague Dawley rats: 1. an investigation of the dose-response relationship between oxotremorine and hypothermia; 2. an examination of the effect of housing on the oxotremorine-induced hypothermic response, and 3. an investigation of the acute administration of various doses of atropine sulphate on the hypothermia caused by oxotremorine. The results indicate that the dose-response relationship between oxotremorine and the antagonism of hypothermia is similar in rat as it is in mice. The results also showed that this effect did not occur in group-housed animals.     

Degree of Somatoform and Psychological Dissociation in Dissociative Disorder Is Correlated with Reported Trauma

In this study, the prevalence and severity of traumatic experiences as reported by patients with dissociative disorders and with other DSM-IV psychiatric diagnoses were compared. Furthermore, the predictive value of emotional, physical, and sexual trauma with respect to somatoform and psychological dissociation was analyzed. In contrast with comparison patients, dissociative disorder patients reported severe and multifaceted traumatization. Physical and sexual trauma predicted somatoform dissociation, sexual trauma predicted psychological dissociation as well. According to the memories of the dissociative disorder patients, this abuse occurred in an emotionally neglectful and abusive social context. Pathological dissociation was best predicted by early onset of reported intense, chronic and multiple traumatization. Methodological limitations restricting causal inferences between reported trauma and dissociation are discussed.     

Experimental models of colorectal cancer

PURPOSE: A review ofin vivo andin vitro models of colorectal cancer is presented. METHODS: A retrospective literature review was performed with reference to CD-ROM Medline and Index Medicus. RESULTS: A comparison of the advantages and disadvantages of the models is presented in addition to a summary of individual model methodology and applications. CONCLUSIONS: Such models are a useful adjunct for surgical research in colorectal oncology.Mr. Banerjee is in receipt of support from the Yorkshire Cancer Research Organization.     

Visual and psychomotor performance of elite,intermediate and novice table tennis competitors

The purpose of this cross-sectional study was to determine whether measures on a selected groups of visual and psychomotor variables distinguished between groups of elite, intermediate and novice table tennis players. The variables included commonly of Melbourne measured clinical functions such as static visual acuity, extent of visual field and oculomotor balance and more experimental visual tasks such as recognition of, peripheral targets, saccadic latency and dynamic visual acuity. Psychomotor performance was assessed by measures of simple reaction time, choice response time and hand movement time. Although elite level competitors had significantly better dynamic visual acuity, a wider visual field and superior recognition of peripheral targets compared to less skilled competitors, the magnitude, or practical significance of these differences was not great and individually accounted for less than 5 per cent of population variance. Elite competitors had significantly faster psychomotor responses than novice players with die skill variables individually accounting for between 21 per cent and 62 per cent of population variance in psychomotor performance. These results indicate that the psychomotor parameters could be a useful part of a test battery for talent identification amongst table tennis players.     

Petit Mal-Grand Mal ECT: A Method to Induce Seizures Without Barbiturate Anesthesia

Petit mal-grand mal (PM-GM) electroconvulsive therapy (ECT) is a technique developed by Impastato to elicit unconsciousness with a subconvulsive electrical stimulus, rather than with barbiturate anesthesia. Muscle relaxation is produced with succinylcholine chloride before stimulus is applied. The cases reported here illustrate applications of the technique to depressed patients with severe cardiac and pulmonary disease, and the use of PM-GM ECT in a patient in whom seizures could not be elicited by the usual ECT technique is described.     

Intestinal 5-Fluorouracil Absorption: Use of Ussing Chambers to Assess Transport and Metabolism

We have employed an in vitro system to study transport and metabolism of organic molecules by gastrointestinal tissues. Such a system would aid in the evaluation of the potential for oral delivery of organic molecules. Transport and metabolism of 5-fluorouracil (5-FU) were studied using rabbit intestinal preparations. Unidirectional fluxes and metabolism were measured in vitro in Ussing chambers under short-circuit conditions. Results from these studies reveal that in ileum, proximal, and distal colon, steady-state fluxes of 5-FU (10 µM added to both bathing solutions) are established after 30 min and remain constant for at least 110 min. Transport of 5-FU under sink conditions with 10 µM 5-FU present in the mucosal or serosal bathing solution alone demonstrated similar rates of transport as under nonsink conditions. The concentration dependence of 5-FU fluxes indicates that the mucosal (m)-to-serosal (s) flux is composed of both a saturable and a linear component over the range of 1–100 µM in the ileum, whereas the s-to-m flux in the ileum and both fluxes in the colon are linear functions of concentration. Over the concentration range employed and the time course of these studies, 5-FU had no effect on the electrical properties of the ileum or colon. In the ileum, the m-to-s but not the s-to-m flux of 5-FU was reduced by (1) serosal ouabain (0.1 mM); (2) reduction of the bathing solution Na concentration; and (3) addition of uracil, thy mine, thymidine, uridine, 2-deoxyuridine, or uridine-5-monophosphate. These results indicate that 5-FU absorption in the ileum occurs by a Na-dependent mechanism that is inhibited by uracil and structurally related compounds. In distal colon, no evidence for an active transport mechanism was obtained. High-performance liquid chromatography (HPLC) analysis reveals that both ileum and distal colon metabolize 5-FU to more polar compounds. Metabolism in ileum is quantitatively greater than in distal colon. Metabolites are found predominantly on the side to which transport has occurred, suggesting that metabolism occurs concomitantly with transport. Since the intestinal cells metabolize 5-FU to more polar compounds and active absorption is inhibited in a competitive manner by related compounds, these results may provide an explanation for the variable oral activity reported for 5-FU.     

Factors influencing the likelihood of successful decisions to treat dentin caries from bitewing radiographs

The purpose of this study was to describe the role played by the ability to estimate caries depth in successfully deciding to treat dentin caries when making use of bitewing radiographs as a diagnostic test. A 10% random sample (n = 444) of Dutch dental practitioners was sent a two-wave questionnaire concerning radiographic caries diagnosis and restorative treatment decision making. The second wave consisted of simulated bitewing radiographs of 105 tooth surfaces with and without dentin caries according to two measuring standards: (a) a micro-radiographic "gold" standard and (b) a norm of expert observers. The dentists were asked to diagnose caries at 4 depths of penetration using a 5-point certainty scoring system to measure diagnostic ability; and to make a treatment decision for each surface. The overall response was 61% (273). A regression analysis was carried out using the chance per dentist of correctly deciding to treat dentin caries as the dependent variable. The degree of agreement with the experts' diagnosis of radiographic caries depth was used to create variables measuring diagnostic ability. Five significant (P less than 0.05) variables explained 60% (R2 = 0.60) of the variation in decision making. The best diagnostic ability variable explained 47% of the variation while the treatment criterion reportedly used explained 3%. We conclude that the ability of practitioners to interpret radiographs plays a major role in treatment decision making and that their reported treatment decision making criteria should not be taken at face value.     

Efficacy of ECT in Psychotic and Nonpsychotic Depression

The authors examined reports addressing the question of whether electroconvulsive therapy (ECT) is more effective in psychotic or nonpsychotic depressive disorders. Most ECT studies did not consider the issue directly, and those that did had varying methodologies and results. The authors then analyzed the data of 33 depressed patients to clarify the differential response to ECT in 13 psychotic and 20 nonpsychotic patients. The subjects were also examined as to type of electrode placement. ECT produced a greater reduction in Hamilton Depression Rating Scale scores in the psychotic depressives as compared to the nonpsychotics after an average of 9.2 treatments. The two patients who were nonresponders to ECT were both nonpsychotic.