Methodological problems in the study of classical aversive conditioning of adrenocortical responses

The present studies were conducted to demonstrate classical aversive conditioning of a corticosterone stress response in male rats. In the first experiment animals exposed to an odor which had previously preceded tube restraint stress had significantly higher plasma corticosterone levels than animals which were probed with a novel odor, or animals in which stress was followed, rather than preceded, by the odor. Careful consideration of corticosterone responses obtained on different days during training made it impossible to conclude unequivocally that learning had occurred. A second experiment was designed specifically to deal with the problems raised by the first, but we were again unable to show rigorously that learning had taken place. However, with data and paradigms comparable to our own, other researchers have prematurely concluded that aversive visceral conditioning can occur. It is suggested that the methodological considerations raised in the present studies could also be important for interpreting other experiments. Given the classical importance ascribed to learning components in many psychosomatic pathologies, future experiments are necessary to determine if stress responses can be classically conditioned, but they must be more rigorously designed than in the past.     

Preliminary evidence for a role of apolipoprotein E alleles in identifying haemodialysis patients at high vascular risk

Conventional risk factors have very low predictive power in identifying haemodialysis patients at high risk of vascular accidents. A role for apolipoprotein E isotypes was looked for in a small, but rigorously defined, cohort of longterm haemodialysis patients. In individuals with high vascular risk, as identified by higher common carotid intima/media thickness, we found an excess of apolipoprotein E4 alleles. This preliminary result requires confirmation in large patient cohorts.      

Adrenocortical and behavioral responses to repeated stressors: toward an animal model of chronic stress and stress-related mental illness

Research in chronic stress has been hampered by the absence of an operational definition for that condition. To explore possible criteria for chronic stress, we repeatedly exposed rats to 2 hr of tail shock per day. After several days, we found elevated prestress corticosterone levels and abnormal behavior, including decreased food consumption, fear-like suppression of activity immediately before stress, greater hesitancy to drop from a suspended wire, and decreased exploratory behavior in a novel environment. A less intensely stressed group of rats also had elevated prestress corticosterone levels, but not the abnormal behaviors that persisted in shocked rats after the stress sessions were discontinued. We propose that abnormalities in both adrenocortical function and behavior are a better marker for chronic stress than abnormalities in either of these systems alone. The animal model we have described may be useful for studying factors that contribute to development of chronic stress or PTSD.     

Hodgkin disease: CT of the thymus

The computed tomography (CT) scans in two groups of patients with Hodgkin disease were reviewed to determine the frequency of thymic enlargement. In 50 CT scans from 50 patients with evidence of thoracic disease on CT scans who were examined for primary staging, the thymus was enlarged in 15 of 50 (30%). Fifty CT scans were obtained from 44 patients at the time of 50 separate episodes of known or suspected relapse. Relapse occurred in the mediastinum in 12 episodes, lung parenchyma in five, and both sites in one. Thymic enlargement thought to be due to involvement by disease was present in seven of 18 (38%). Mediastinal disease was associated with thymic enlargement in all but one patient in whom a thymic cyst developed after radiation therapy. Differentiation of thymic enlargement from enlarged superior mediastinal lymph nodes was easily made in all but two patients. Thymic enlargement in the absence of lymph node enlargement may indicate a different disease, since isolated Hodgkin disease of the thymus is uncommon. Primary thymic tumor should be considered initially, whereas after treatment, rebound hyperplasia of the thymus may be the cause of enlargement.     

Solitary bronchioloalveolar carcinoma: CT criteria

The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.     

A randomized controlled trial of electromagnetic therapy in the primary care management of venous leg ulceration

OBJECTIVE: The aim was to establish the potential efficacy, tolerabilityand side-effect profile of electromagnetic therapy as an adjunctto conventional dressings in the treatment of venous leg ulcers. METHOD: A prospective, randomized, double blind controlled clinicaltrial was carried out in a dedicated leg ulcer clinic basedin one urban general practice. Nineteen patients with leg ulcersof confirmed venous aetiology were assessed. The main outcomemeasures were rate and scale of venous leg ulcer healing, changesin patient-reported pain levels, quality of life, degree ofmobility, side effect profile and acceptability to patientsand staff. RESULTS: Sixty-eight per cent of patients attending this dedicated clinicachieved improvements in the size of their ulcer (4, 21%, healedfully) and in reduced pain levels (P < 0.05) during the trial,despite the chronicity of ulcer histories. Patients treatedwith electromagnetic therapy at 800 Hz were found at day 50to have significantly greater healing (P < 0.05) and paincontrol (P < 0.05) than placebo therapy or treatment with600 Hz. All patients reported improved mobility at the end ofthe study. The electromagnetic therapy was well tolerated bypatients, with no differences between groups in reporting adverseevents, and proved acceptable to staff. CONCLUSION: Despite the small numbers in this pilot study, electromagnetictherapy provided significant gains in the healing of venousleg ulcers and reduction in pain. Keywords. Electromagnetic therapy, RCT, leg ulcers, primary care.