Mental Energy: Assessing the Cognition Dimension

The cognitive dimension of mental energy can be assessed by tests of vigilance and choice reaction time. These behaviors are relatively simple cognitive functions and can be measured with precision and reliability if carefully designed and implemented tests are used. Because the concept of mental energy is still evolving, the selection of appropriate tests to assess it must be tentative. However, vigilance and choice reaction time seem to have the necessary psychometric properties for assessing mental energy, including construct, predictive content, and face validity. Tests of reaction time and vigilance are correlated with questionnaires that measure mood states corresponding to mental energy—such as sleepiness, fatigue, and alertness—in the expected manner and are of approximately equivalent sensitivity.     

Retinal accumulation of the phosducin/T beta gamma and transducin complexes in developing normal mice and in mice and dogs with inherited retinal degeneration

Rod photoreceptors of mammalian retinas contain a 33-kDa phosphoprotein, phosducin, which complexes with the beta, gamma-subunits of transducin (T beta gamma). The level of phosducin phosphorylation is modulated by light, suggesting that the phosducin/T beta gamma complex has a pivotal role in light-regulated events that occur in photoreceptors. We have investigated, in developing mouse retinas, the age at which the complex is first detected and the subsequent accumulation of the phosducin/T beta gamma complex during postnatal life. Western blot analysis detected immunoreactivity both for phosducin and T beta in retinal homogenates of 3-day-old mice. Thereafter, the level of immunoreactivity for both proteins increased steadily, to reach adult levels in the next 2 postnatal weeks. Gel filtration analysis of extracts from immature mouse retina showed that phosducin and T beta co-eluted, like the phosducin/T beta gamma complex of adult retina, as a 77-kDa complex, indicating that the phosducin/T beta gamma complex is formed when photoreceptors first synthesize the components of the complex. While the levels of the phosducin/T beta gamma complex increased steadily during the first 2 postnatal weeks, the subunits of transducin complex, T alpha together with additional amounts of T beta gamma, only started to appear around the 7-9th postnatal day, and the level of transducin complex increased sharply at 11-14 days to reach adult levels that are similar to those of phosducin/T beta gamma complex.(ABSTRACT TRUNCATED AT 250 WORDS)     

Growth hormone therapy in the elderly: implications for the aging brain.

Growth hormone (GH) secretion declines during normal aging, resulting in lower serum insulin-like growth factor (IGF)-I levels. It has been proposed that many of the catabolic changes seen in normal aging, including osteoporosis and muscle atrophy, are in part caused by the decreased action of the GH-IGF-I axis. In addition, patients with GH deficiency have increased overall cardiovascular mortality. Several investigators have initiated GH treatment for elderly patients with relative hyposomatotropinemia. Initial reports suggest that GH can increase muscle mass, improve exercise tolerance, increase REM sleep and cause an enhanced sense of well-being. The basis for neuropsychiatric changes during GH therapy may be due to a direct CNS action of GH itself, to the increased IGF-I secretion which GH elicits, or to enhanced functioning of peripheral organ systems. Long-term studies will determine whether GH or IGF-I can exert a neurotrophic action in the aging brain.     

MR of thoracic cord compression caused by epidural extramedullary hematopoiesis in myelodysplastic syndrome.

Spinal cord compression caused by extramedullary hematopoiesis is a rare complication of chronic anemic states, most frequently occurring in patients with beta-thalassemia. We report the MR appearance of extramedullary hematopoiesis resulting in cord compression in a patient with a myelodysplastic syndrome, which was isointense with the spinal cord on T1-weighted images and markedly hypointense on fast spin-echo T2-weighted images, and that demonstrated enhancement.     

Development and validation of an instrument to measure occupational stress in speech-language pathologists

The Speech-Language Pathologist Stress Inventory (SLPSI) is a 48-item questionnaire adapted from the Teacher Stress Inventory (Fimian, 1988). Factor analyses of the responses of 626 speech-language pathologists revealed four stress source factors (Bureaucratic Restrictions, Time and Workload Management, Lack of Professional Supports, and Instructional Limitations) and two stress manifestation factors (Emotional-Fatigue Manifestations and Biobehavioral Manifestations). The internal consistency reliability of scales based on these factors ranged from .71 to .87, with .93 for the entire scale. Evidence for construct validity was found in moderate positive correlations between the scales of the SLPSI and the scales of the Maslach Burnout Inventory (MBI) (Maslach & Jackson, 1986). Stress and burnout subscale intercorrelations ranged from .10 to .82 (p less than .01), and the correlation between stress strength and burnout frequency was .66 (p less than .001).     

Catheter-related thrombosis in patients with refractory lymphoma undergoing autologous stem cell transplantation.

Long-term indwelling central venous catheters have eased the administration of drugs, blood products, and hyperalimentation to patients with cancer. However, their use is associated with thrombotic complications. We report here on the thrombotic complications prospectively observed in 46 patients with refractory lymphoma (22 Hodgkin's disease, 24 non-Hodgkin's lymphoma) who had placement of one or more catheters in preparation for autologous stem cell transplantation (ASCT). Thrombosis of 26 catheters in 19 patients was observed. Specific abnormalities of hemostasis were equally common in patients who developed thrombosis and in those who did not. Thrombotic complications were more common in patients with Hodgkin's disease (13/22) than in patients with non-Hodgkin's lymphoma (6/24, p = 0.04). Although more patients with Hodgkin's disease had received prior splenectomy and/or irradiation to the area involved by thrombosis than patients with non-Hodgkin's lymphoma, the incidence of splenectomy and irradiation was similar for patients with Hodgkin's disease who developed thrombosis and those who did not. Therefore, although the etiology remains unexplained, patients with Hodgkin's disease undergoing intensive chemotherapy and ASCT appear to have a higher incidence of catheter-related thrombosis than patients with non-Hodgkin's lymphoma undergoing similar therapy.