Seasonal variation of mixed and pure episodes of bipolar disorder

BACKGROUND: Although seasonal patterns of manic episodes have been reported, the seasonal variation of mixed states of bipolar disorder has received little attention. In the current report we address that concern as well as the overall seasonality of manic episodes. METHODS: The seasonal pattern of 304 psychiatric hospital admissions for treatment of mixed or manic bipolar episodes over a 3-year period were analyzed employing two definitions of mixed manic states: DSM-III-R and an ROC derived definition. RESULTS: The frequency of all manic episodes combined peaked in early spring, with a nadir in late fall. Pure manic admissions showed a similar pattern. Mixed manic admissions had a significantly different pattern, with a peak in late summer and a nadir in November. The differences between pure and mixed manic admissions were demonstrated with the use of the ROC definition for mixed states. LIMITATIONS: Effects of medications and medication non-compliance may dampen natural seasonal patterns of episodes. CONCLUSIONS: The different seasonal pattern of mixed and pure manic episodes support the separation of mixed episodes as a distinct clinical subtype.     

Expression of a novel combination of fast and slow troponin T isoforms in rabbit extraocular muscles

Summary The properties of extraocular muscles (EOMs) are quite different from those of the trunk and limb. Here we show that there is a novel pattern of troponin T (TnT) expression in EOMs which most likely contributes to the fine control of ocular movement and may reflect their innervation by cranial motoneurons. Three regions of the muscle were analysed to distinguish the TnT isoforms present in the fast singly-innervated fibres from those in the multiply-innervated fibres. More than 95% of the TnT in the singly-innervated fibres is TnT_3f, which exhibits the most graded response to changes in calcium concentration during activation (Schachatet al., J. molec. Biol. 198, 551–4). In multiply-innervated fibres, which exhibit tonic contractures, the slow troponin T TnT_2s is expressed. While neither TnT_3f nor TnT_2s is unique to EOM, this pattern is unusual in two respects: first, both TnT_3f and TnT_2s are minor components of the trunk and limb musculature, and second, most muscles express several fast and both slow TnT species. Although EOM occupies a highly specialized physiological niche, its unusual physiology is not reflected in the presence of new TnT isoforms but in the expression of a different ratio of the known species of TnT.     

Impedance plethysmography in the diagnosis of arterial and venous disease

The objective of this paper is to review the theoretical basis and clinical application of electrical impedance plethysmography in the noninvasive evaluation of peripheral arterial and venous disease. Theoretical, experimental and clinical studies have now demonstrated a direct relationship between electrical impedance changes and limb volume changes. Potential sources of error have also been identified. This has led to the development of clinical tests based on impedance plethysmography for the detection of peripheral arterial disease, venous insufficiency and venous outflow obstruction. Impedance plethysmography, using the method of venous occlusion, is presently the most commonly employed noninvasive method for the detection of deep venous thrombosis.     

Familial renal carcinoma

Renal carcinoma developed in two or more members of nine families. Multiple generations were affected in five kindreds, and siblings in four. The median age at cancer diagnosis was a decade earlier than usual, and individual patients had bilateral or multifocal lesions; these are features of hereditary forms of diverse cancers. No patient had von Hippel-Lindau disease or other predisposing genetic syndromes. Karyotypes of the peripheral blood of nine persons showed no instance of a 3;8 chromosome translocation as recently reported in association with renal carcinoma in ten members of one family. The findings show that familial renal cancer is more common than previously reported in the literature.     

The use of computer-assisted diagnosis in cardiac perfusion nuclear medicine studies: A review (part 3)

Computer-assisted diagnosis (CAID) is commonly used to evaluate cardiac nuclear medicine studies such as thallium perfusion scans. Part 1 of this series (Journal of Digital Imaging, 5:209–222, 1992) reviewed the basic theory underlying CAID in nuclear medicine and its use in planar thallium imaging. Part 2 discussed the application of CAID to SPECT perfusion studies (Journal of Digital Imaging, 6:1–15, 1993). This article reviews new variations of CAID programs for SPECT imaging and the application of expert systems and neural networks to CAID of nuclear medicine perfusion studies.     

Repeated measurement of nasal lavage fluid chemokines in school-age children with asthma.

BACKGROUND: Inflammatory processes at the mucosal surface may play a role in maintenance of asthma pathophysiology. Cross-sectional studies in asthmatic patients suggest that chemokines such as interleukin 8 (IL-8) are overproduced by respiratory epithelium. OBJECTIVE: To test the hypothesis that chemokine levels are persistently elevated in the respiratory secretions of asthmatic children at a stable baseline. METHODS: We measured nasal lavage fluid (NLF) levels of chemokines and other mediators at 3- to 4-month intervals in a longitudinal study of asthmatic children, with nonasthmatic siblings as controls. RESULTS: In a linear mixed-model analysis, both family and day of visit had significant effects on nasal mediators. Thus, data for 12 asthmatic-nonasthmatic sibling pairs who had 3 or more same-day visits were analyzed separately. For sibling pairs, median eosinophil cationic protein levels derived from serial measurements in NLF were elevated in asthmatic patients compared with nonasthmatic patients, with a near-significant tendency for elevation of total protein and eotaxin levels as well. However, no significant differences were found for IL-8 or several other chemokines. Ratios of IL-13 or IL-5 to interferon-gamma released by house dust mite antigen-stimulated peripheral blood mononuclear cells, tested on a single occasion, were significantly increased for asthmatic patients. CONCLUSIONS: Substantial temporal and family-related variability exists in nasal inflammation in asthmatic children. Although higher levels of eosinophil cationic protein are usually present in NLF of patients with stable asthma compared with patients without asthma, chemokines other than eotaxin are not consistently increased. Eosinophil activation at the mucosal surface is a more consistent predictor of asthmatic symptoms than nonspecific elevation of epithelium-derived inflammatory chemokine levels.     

Clerkship directors' perceptions of the effects of managed care on medical students' education.

PURPOSE: Little is known about the effect of managed care on medical students' education. Because clerkship directors (CDs) are especially well positioned to observe any changes, this study surveyed CDs from six medical specialties about their perceptions of the effects of managed care on medical students' education. METHOD: Anonymous questionnaires were mailed to 808 CDs from departments of six medical specialties at 125 U.S. allopathic medical schools between October 1997 and March 1998. Among other questions, respondents were asked whether they had observed changes in 19 different aspects of medical students' education, whether these changes were beneficial or detrimental, and whether they believed the changes were due to managed care and/or to other factors. Results were analyzed to determine perceptions of the overall magnitude and source(s) of changes, the perceived positive versus negative effect of managed care, and whether these outcomes were statistically associated with the perceived degree of managed care's market penetration. RESULTS: Five hundred questionnaires (61.9%) were returned. For full-time and voluntary faculty teaching, faculty availability for educational administration, directors' clinical responsibilities, and quality of professional life, the most common response was that managed care had an adverse effect. For faculty's enthusiasm for teaching, directors' administrative and educational duties, and clerkship training sites, the second most common response after "not changed" was that managed care had a negative effect. The majority of respondents held negative opinions of managed care and thought that medical students did not understand it. CONCLUSIONS: CDs in six medical specialties perceived that managed care has negatively affected medical students' education. These perceptions may influence medical students' education. Measures must be taken to ensure excellent education through adequate resources and training in the context of high-quality medical care.     

Comparison of DNA- and RNA-based methods for detection of truncating BRCA1 mutations

A number of methods are used for mutational analysis of BRCA1, a large multi-exon gene. A comparison was made of five methods to detect mutations generating premature stop codons that are predicted to result in synthesis of a truncated protein in BRCA1. These included four DNA-based methods: two-dimensional gene scanning (TDGS), denaturing high performance liquid chromatography (DHPLC), enzymatic mutation detection (EMD), and single strand conformation polymorphism analysis (SSCP) and an RNA/DNA-based protein truncation test (PTT) with and without complementary 5' sequencing. DNA and RNA samples isolated from 21 coded lymphoblastoid cell line samples were tested. These specimens had previously been analyzed by direct automated DNA sequencing, considered to be the optimum method for mutation detection. The set of 21 cell lines included 14 samples with 13 unique frameshift or nonsense mutations, three samples with two unique splice site mutations, and four samples without deleterious mutations. The present study focused on the detection of protein-truncating mutations, those that have been reported most often to be disease-causing alterations that segregate with cancer in families. PTT with complementary 5' sequencing correctly identified all 15 deleterious mutations. Not surprisingly, the DNA-based techniques did not detect a deletion of exon 22. EMD and DHPLC identified all of the mutations with the exception of the exon 22 deletion. Two mutations were initially missed by TDGS, but could be detected after slight changes in the test design, and five truncating mutations were missed by SSCP. It will continue to be important to use complementary methods for mutational analysis.