Munchausen's syndrome by telemetry.
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Biomedical subjects
Publications and source records attributed to K Hart.
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We have devised a test for cell autonomy of a gene that is switched on ectopically in a clone of cells, allowing us to ask whether the wild-type activity of this gene can influence neighbouring cells. To switch on the test gene, we used the yeast FRT system, and marked the FRT-generated cell clone by co-expressing beta-galactosidase. Co-expression is achieved by a stretch of 5' untranslated mRNA from the homeotic gene Ultrabithorax (Ubx), which is inserted between the two coding sequences. We show that this Ubx sequence mediates efficient and reliable di-cistronic mRNA translation in wing imaginal discs of Drosophila. Applying our test to Ubx, we find that ectopic Ubx in wing discs strictly coincides with beta-galactosidase expression. Consequently, wing cells are transformed into cells that appear to be intermediates between wing and haltere cells, contesting the view that homeotic genes act as binary switches.
OBJECTIVE: The changing profiles of spinal cord injuries in South Africa are addressed in this study. DESIGN: A retrospective analysis of 551 patients with spinal cord injury. MATERIALS AND METHODS: The cause of injury was motor vehicle crashes in 30%, stab wounds in 26%, gunshot wounds in 35%, and miscellaneous causes 9%. MEASUREMENTS AND MAIN RESULTS: There was a significant shift from stab wounds towards bullet wounds over the last five years. Bullet spinal cord injuries increased from 30 cases in 1988 to 55 cases in 1992, while stab spinal cord injuries decreased from 39 cases in 1988 to 20 cases in 1992. The incidence of spinal cord injuries following a motor vehicle crash showed a declining tendency after a transient increase (28 cases in 1988, 40 in 1990, 31 in 1992). Moreover, the problem of severe septic complications has been investigated and various risk factors for sepsis that might impair the rehabilitation process have been examined. The risk of developing septic complications was higher in gunshot spine injuries (21 cases out of 193) than in knife injuries (5 cases out of 143). The presence of a retained bullet did not seem to increase the chances for sepsis. In seven patients the sepsis was the direct consequence of the retained bullet while in 14 patients sepsis developed with no bullet in situ. Furthermore, the site of the injury (cervical, thoracic, lumbar spine) did not correlate with the abovementioned risks. CONCLUSIONS: Gunshots carry a heavier prognosis. Only 32% of our gunshot cases underwent a significant recovery as opposed to 61% of stab cases and 44% of the motor vehicle crash victims.
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The human cell surface transmembrane protein CD36 has important roles in cell adhesion and signal transduction. There is a related rat protein, LIMP II (also known as rLGP85), which is a well-characterized lysosomal membrane protein. The two proteins define a distinct family of receptor molecules with two membrane-spanning domains. We have identified a new member of this family, encoded by a Drosophila gene called emp (epithelial membrane protein). The emp protein, as predicted from the nucleotide sequence, is 519 amino acid residues long. It shows striking similarity throughout most of its sequence to both CD36 and LIMP II. Drosophila emp transcripts are expressed during embryogenesis in various epithelial cell types derived from the ectoderm. During larval development, we detect emp transcripts in the epithelial cells of wing imaginal discs, in the precursor cells for adult epidermal structures. These expression patterns suggest a role of emp protein in the development or cellular function of epithelial cells.
E(Dl)KP135 has been isolated previously as a recessive lethal Drosophila P element insertion line with a dominant enhancing effect on the phenotype of Delta, a gene encoding a surface membrane protein. We show here that this P insertion also enhances the wing phenotype of nd1, an allele of Notch encoding another transmembrane protein, the putative receptor of Delta, as well as that of if3, an allele of the integrin gene PS2 alpha. Moreover, we noticed that this P insertion causes a severe Minute phenotype. Molecular characterisation revealed that the P element disrupts the putative mRNA leader sequence of the ribosomal protein L19 gene. We tested further Minute genes and found that two of them, similarly to E(Dl)KP135, strongly enhance the nd1 wing phenotype. Our results suggest that the pleiotropic Minute syndrome can affect, probably indirectly, one or more steps of wing morphogenesis that involve surface adhesion of epithelial cells.
The present study examined the relationship among psychiatric diagnosis, depression, attributional style, and hopelessness among 69 adolescent suicide attempters and 40 psychiatrically hospitalized adolescent controls. Contrary to predictions, the suicide attempters were more likely than the nonsuicidal group to attribute good events to global causes. No differences in attributional style were found across the depressed versus nondepressed subjects. However, there was a modest relationship between depression and attributional style. Results suggest that maladaptive cognitive characteristics are present in adolescent clinical samples but may be less specific to suicide attempters than is often suggested.
A kindred with a familial hemoglobinopathy and familial primary pulmonary hypertension with autosomal dominant transmission has been identified. Affected family members were obvious from their cyanosis due to a reduced affinity for oxygen by the hemoglobin variant. The mother and one child had clinical pulmonary hypertension, whereas two siblings had cyanosis and preclinical pulmonary vascular disease as evidenced by abnormal perfusion lung scans and elevated levels of fibrinopeptide A in the face of normal pulmonary hemodynamics. In one, pulmonary hypertension could be induced with exercise. The studies on this family support the hypothesis that primary pulmonary hypertension may be initiated by abnormalities of the pulmonary vascular bed that predispose to in situ thrombosis. The possible common genetic transmission of the two diseases offers the speculation that the gene that confers predisposition to pulmonary hypertension may be located near the gene responsible for beta globulin.
Pulmonary hypertension causes right ventricular ischemia and failure as a result of increased afterload combined with reduced coronary blood flow. Increasing coronary driving pressure by raising aortic pressure with phenylephrine has been shown to reverse right ventricular ischemia from pulmonary hypertension in animals. Since vasodilators often fail to reduce afterload, we tested whether raising the coronary driving pressure would improve right ventricular function in man. Ten patients with pulmonary hypertension had hemodynamics and right ventricular coronary driving pressure measured before and 10 minutes after a steady state was reached with a phenylephrine infusion titrated to raise aortic pressure by 25 percent. Phenylephrine caused a significant (p less than .01) increase in mean aortic pressure (84 to 108 mm Hg) and right ventricular coronary driving pressure (46 to 69 mm Hg). In response, there was a significant (p less than .01) rise in mean pulmonary artery pressure (58 to 67 mm Hg), right ventricular end-diastolic pressure (10 to 16 mm Hg) and wedge pressure (5 to 9 mm Hg), and an insignificant fall in cardiac output (3.26 to 3.09 L/min) and pulmonary artery O2 saturation (57 to 49 percent). Although phenylephrine increased right ventricular coronary driving pressure, it worsened right ventricular function as manifest by a rise in end-diastolic pressure and fall in cardiac output. Any benefit of raising right ventricular coronary driving pressure may have been offset by alpha vasoconstriction of right ventricular coronary blood flow and/or pulmonary arterial vasoconstriction. Phenylephrine does not appear to be a useful therapy of right ventricular failure from pulmonary hypertension in patients who fail vasodilators.
We conducted a national survey of psychologists who offer neuropsychological services to determine levels of training, current practices, and views on professional issues. All subjects were listed in the National Register of Health Service Providers in Psychology and/or the American Psychological Association Directory as having some affiliation with neuropsychology. Results suggest marked diversity within the field, with the modal practitioner being minimally involved in neuropsychological activities. We also compare clinicians with varying involvement and experience in neuropsychology and analyze the concentration of practitioners by geographic regions. We compare our results to those obtained in prior surveys and discuss implications of the findings.
The relationship among depression, social skills, and suicidal behavior was examined in a sample of 41 adolescents hospitalized in a general medical setting following a suicide attempt. These subjects were compared to 40 nonsuicidal psychiatrically hospitalized adolescents. Level of depression, assessed using the Children's Depression Inventory (CDI), and social skills, assessed via the Matson Evaluation of Social Skills with Youngsters (MESSY), were evaluated for all subjects. The suicide attempters and psychiatrically hospitalized patients were not found to differ on either the CDI or MESSY. However, multiple regression analyses revealed the factor scores of the MESSY to be related to depression in both patient groups. The data provide support for the relationship between social skills and depression. Results are also discussed in terms of the similarities between adolescent suicide attempters and nonsuicidal psychiatrically disturbed adolescents.
We have used an irradiation and fusion technique to generate somatic cell hybrids that contain human chromosomal fragments. As a model system, a human-hamster hybrid containing a single human X chromosome was gamma-irradiated and fused with a rodent line. Hybrids were obtained without imposing direct selection for human material. Analysis of 29 clones by in situ hybridization and Southern blotting revealed that human fragments were incorporated into the hybrid cell genomes in most lines. Like chromosome-mediated gene transfer (CMGT)-generated hybrids, these hybrids contained multiple human fragments and retained alphoid centromeric sequences with a high frequency. However, unlike the CMGT, human fragments (apart from alphoid sequences) of less than 10(7) bp showed no evidence for rearrangements. This technique provides a method for constructing hybrids that contain a limited number of small human fragments derived exclusively from any chromosome of choice without the need to impose selection. Such hybrids provide a valuable resource for high-resolution mapping over short distances and for the isolation of disease and other loci mapped genetically.
Cloned cDNA sequences representing exons from the Duchenne/Becker muscular dystrophy (DMD/BMD) gene were used for deletion screening in a population of 287 males males affected with DMD or BMD. The clinical phenotypes of affected boys were classified into three clinical severity groups based on the age at which ambulation was lost. Boys in group 1 had DMD, losing ambulation before their 13th birthday; those in group 2 had disease of intermediate severity, losing ambulation between the ages of 13 and 16 years; and boys in group 3 had BMD, being ambulant beyond 16 years. A fourth group consisted of patients too young to be classified. Clinical group allocation was made without previous knowledge of the DNA results. A gene deletion was found in 124 cases where the clinical severity group of the affected boy was known. The extent of the deletions was delineated using cDNA probes. There were 74 different deletions. Fifty-five of these were unique to individual patients, but the other 19 were found in at least two unrelated patients. The different clinical groups showed generally similar distributions of deletions, and the number of exon bands deleted (that is, deletion size) was independent of phenotype. Some specific deletion types, however, correlated with the clinical severity of the disease. Deletion of exons containing HindIII fragments 33 and 34 and 33 to 35 were associated with BMD and were not found in patients with DMD. Deletions 3 to 7 occurred in four patients with the intermediate phenotype and one patient with BMD. Other shared deletions were associated with DMD, although in four cases patients with disease of intermediate severity apparently shared the same deletion with boys with DMD. The range of phenotypes observed, and the overlap at the genetic level between severe and intermediate and mild and intermediate forms of dystrophy, emphasizes the essential continuity of the clinical spectrum of DMD/BMD. There were no characteristic deletions found in boys with mental retardation or short stature which differed from deletions in affected boys without these features.
Because a definitive diagnosis of pulmonary hypertension requires cardiac catheterization, there have been no data on the prevalence of pulmonary hypertension in the general population. The diameter of the right descending pulmonary artery, as measured from chest roentgenograms, has been used by clinicians as a noninvasive indicator of pulmonary hypertension. Chest roentgenograms from the Second National Health and Nutrition Examination Survey, a sample survey of the US civilian noninstitutional population, were used in conjunction with estimates of sensitivity and specificity of this technique determined from patients who underwent right heart catheterization to estimate the prevalence of pulmonary hypertension (mean pulmonary artery pressure greater than 20 mm Hg at rest) in the US population aged 25 years and older. The prevalence is estimated to be very low in the population at large, primarily because of the low prevalence in women of all ages. The prevalence in men is 13.4 percent above age 34, and increases to 28.2 percent above age 64. Thus, in elderly men, pulmonary hypertension is relatively common and may have an important impact in the management of this age group.
We surveyed assumptions with regard to the relation between age and outcome of head injury (a.k.a. the "Kennard Principle"). Two groups (N = 120) of practicing clinicians were sent background information about a mild to moderate head injury in which only the age of the patient varied and were asked to predict likely outcome (degree of impairment). Predicted outcome differed significantly, with an adolescent case judged much more likely to have serious impairment than a child case. Implications of the (mis)application of the Kennard Principle are discussed.
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It is often assumed that judgment accuracy improves as clinical training and experience increase, but the few studies on this topic within neuropsychology have yielded negative findings. In an extension of prior research, we obtained information on background training and experience from a nationally representative sample of clinical neuropsychologists and had each practitioner appraise one from among a series of 10 cases. Except for a possible tendency among more experienced practitioners to overdiagnose abnormality, no systematic relations were obtained between training, experience, and accuracy across a series of neuropsychologic judgments. Comparable results were obtained when analysis was limited to the top versus bottom 20% of the sample. This and other studies raise doubt that clinical neuropsychologists train and practice under conditions conducive to experiential learning. The potential benefits of further research on experience and judgment accuracy are discussed.