Effects of chemicals on delayed matching behavior in pigeons I: acute effects of drugs

Pigeons were trained to peck a red or green center key 15 times to turn it off. After a delay, two side keys, one red and one green were illuminated. Pecks on the side key whose color matched the color that the center key had been produced food. Pecks on the other side key produced a timeout. The effects of various drugs were studied as the delay between extinguishing of the center key light and illumination of side keys was varied from 1 to 8 sec. Pentobarbital and phencyclidine consistently decreased matching, but morphine, d-amphetamine and delta 9-tetrahydrocannabinol had little effect on matching even at doses that increased latency to respond and decreased the rate of responding. Pentobarbital frequently decreased matching at doses below those that increased response latency and decreased response rate, but phencyclidine decreased matching only at doses that increased latencies and decreased rates. The effects of pentobarbital on matching did not depend on the delay duration.     

Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography

The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.     

Resting and total energy expenditure in patients with ischemic heart disease.

Total energy expenditure (TEE) was measured by doubly labeled water in 13 preoperative patients undergoing elective coronary artery surgery and compared to resting energy expenditure (REE) measured by indirect calorimetry (IC) calculated from the Harris-Benedict (HB) formula or from formulas based on midarm circumference and arm muscle circumference. Mean REE measured by IC and calculated from the HB, midarm circumference, arm muscle circumference formulas were 62, 75, 62, and 69%, respectively, of TEE measured by doubly labeled water. REE measured by IC correlated significantly with that predicted by the HB (p = 0.006) but not the anthropometric formulas. The relationship between REE derived from anthropometric predictive formulas and REE measured by IC is altered in ischemic heart disease.     

Clinical and Actuarial Prediction of Physical Violence in a Forensic Intellectual Disability Hospital: A Longitudinal Study

Background There is a high rate of physical violence in populations with intellectual disabilities, and this has been linked to problems for the victim, the assailant, members of staff and services. Despite the clinical significance of this behaviour, few studies have assessed methods of predicting its occurrence. The present study examined clinical and actuarial methods of predicting violence in a forensic intellectual disability hospital. Methods The sample for the study consisted of people resident in the hospital during a 1‐year period (n = 124). Clinical prediction used a risk rating made by members of the person's clinical team, whereas actuarial prediction used the number of violent incidents in the 6‐months before the date of the clinical risk assessment. Computerized hospital records of violence in the 6 months after the assessment were used to examine the predictive accuracy of the two methods. Results The clinical method produced an area under the curve of 0.74 (95% CI: 0.65–0.83) in a receiver–operating characteristic curve analysis. The value for the actuarial method was 0.77 (95% CI: 0.69–0.86). Both methods performed at levels significantly above chance, but no one method was found to be superior to the other. Conclusions These findings suggest that it is possible to predict who is at risk of violence in forensic populations with intellectual disabilities. Here, the authors discuss the clinical implications of these findings and the clinical application of risk prediction within clinical services.     

Pulmonary clearance of UICC amosite fibres inhaled by rats during chronic exposure at low concentration.

Clearance of UICC amosite asbestos from the lungs during chronic--that is, repeated--exposure was investigated by using the scanning electron microscope to measure lung burdens from rats which had inhaled amosite asbestos at an approximately constant concentration of 0.1 mg/m3 or, equivalently, 20 fibres/ml for seven hours a day, five days a week for up to 18 months. The lung burdens were compared with previous results for higher exposure concentrations of 1 and 10 mg/m3. Those previous lung burdens had been measured using other analytical methods (infrared spectrophotometry) that were not suitable for the new lower lung burdens. Taken together, these results showed lung burdens rising pro rata with exposure concentration and exposure time. This accumulation of lung burden has been described by a kinetic model that takes account of the sequestration of material at locations in the lung from where it cannot be cleared. Unlike some earlier models in which lung burdens eventually reach a plateau with equilibrium between deposition and clearance during chronic exposure, this sequestration model shows lung burdens continuing to rise with exposure time. The latest results reported here support the application of such a model to lower exposure concentrations closer to those of asbestos in workplaces.     

Maxillary sinusitis in adults: an evaluation of placebo-controlled double-blind trials

BACKGROUND: In general practice, acute sinusitis is frequently diagnosed and treated with antibiotics. OBJECTIVE: This study aimed to determine the evidence for the effectiveness of antibiotic treatment in acute maxillary sinusitis in adults by assessing the methodological quality of placebo-controlled double-blind randomized trials. METHOD: An evaluation by four raters through a 35-item scoring-scale for internal and external validity of all placebo-controlled double-blind randomized trials on acute sinusitis found between January 1966 and July 1996. RESULTS: Eighty-five trials were excluded because they were not placebo-controlled, double-blind, randomized, or were carried out in patients with chronic sinusitis or in children. The three remaining trials were performed in different populations (one in general practice) between 1973 and 1978. Only one study claimed superiority of antibiotic treatment. Different inclusion criteria and major outcome measures were used by the authors. The reliability of major outcome events was reported poorly or not at all and in two studies outcome measures were clinically inappropriate. The studies scored 30-62% of the maximum attainable score for internal validity and 10-20% for external validity. CONCLUSION: The effectiveness of antibiotic treatment in acute maxillary sinusitis in a general practice population is not based sufficiently on evidence.      

Detection of undiagnosed coeliac disease with atypical features using antireticulin and antigliadin antibodies.

Eighteen patients with a variety of non-gastrointestinal symptoms were incidentally found to have circulating antireticulin antibody and on subsequent testing were also positive for antigliadin antibody. They prospectively underwent jejunal biopsy to determine whether or not they had coeliac disease. Their age range was 21-79 years (mean 42 years). Enteropathy was present in 13 (72 per cent) and was always associated with circulating IgA antigliadin antibody. Enteropathy was not present in the five cases who had only IgG antibody. Clinical improvement occurred in eight of 11 patients who complied with a gluten-free diet and was paralleled by an improvement in the mucosal histology in seven of eight who were re-biopsied. The most remarkable cases were two patients who presented with severe debility and no apparent haematological or biochemical abnormalities, and who subsequently made a dramatic recovery on a gluten-free diet. It is concluded that antireticulin antibody detected by routine autoantibody screening and confirmed to have IgA antigliadin antibody specificity is a useful indicator of an otherwise undiagnosed enteropathy. This serves to emphasize that the condition can sometimes be associated with atypical features and significant morbidity.     

Changes in plasma atrial natriuretic factor during sequential fluid removal and biochemical correction in end-stage chronic renal failure patients

Plasma immunoreactive atrial natriuretic factor (ANF) levels, their chromatographic profiles (high-performance liquid chromatography; HPLC) and changes during sequential ultrafiltration (UF; 1 litre/h) and biochemical correction without fluid removal (BC; 3 h) were studied in 8 end-stage chronic renal failure patients on intermittent haemodialysis (greater than 1 year). Patients entered randomly the UF-BC or BC-UF protocols that were reversed after 1 week. HPLC showed a single peak of ANF immunoreactivity in plasma of end-stage chronic renal failure patients before dialysis sessions. ANF at the end of fluid removal fell by 31 +/- 2% (p less than 0.01) during UF-BC and by 30 +/- 2% (p less than 0.01) at the end of BC during BC-UF. In both sequences a further slight reduction in plasma ANF was observed during the second phase: it was 8.5 +/- 5% (n.s.) during BC of the BC-UF and 12.5 +/- 2% (p less than 0.05) during fluid removal of BC-UF. Plasma ANF was not significantly removed by the machinery. BC did not modify the microhaematocrit in the BC-UF sequence while the microhaematocrit was significantly increased by UF (13 +/- 1 and 14 +/- 1%, p less than 0.005 vs. basal, respectively), and decreased by BC in the UF-BC sequence (-5 +/- 2% vs. end UF, p less than 0.05). Serum creatinine and urea decreased significantly during BC in both protocols while they were unmodified during UF. No significant changes were seen in PRC during either protocol.(ABSTRACT TRUNCATED AT 250 WORDS)