Interaction between α- and β-adrenoceptors in rat pineal adenosine cyclic 3′,5′-monophosphate phosphodiesterase activation

Summary The adrenergic regulation of the low-Km pineal cAMP phosphodiesterase (PDE) activity was studied in adult female rats. PDE activity showed a transient enhancement (up to 42%) during the process of degeneration of pineal sympathetic nerve terminals that followed superior cervical ganglionectomy (SCGx), thus confirming the neural modulation of the enzyme. Treatment with isoproterenol (0.3–5.0 mg/Kg) increased significantly PDE activity within 2 hours. Phenylephrine induced a significant increase of pineal PDE only at a 10 mg/Kg dose, while at a lower dose (1 mg/Kg) it potenciated the stimulatory effect of isoproterenol. Treatment of pineal organ cultures with 100 M propranolol inhibited norepinephrine (NE)-induced PDE activity while 100 M phentolamine had no significant effect. Propranolol at doses unable to alter thein vitro NE-induced stimulation of pineal PDE activity (1 M), antagonized such NE effect when used in combination with 1 uM phentolamine. At equimolecular concentrations (1 M) the mixed --adrenergic agonist NE was more effective than the -adrenergic agonist isoproterenol to increase pineal PDEin vitro. These resultsSupported by grant no. 6638, Consejo Nacional de Investigaciones Cientificas y Técnicas de la RepÚblica Argentina (CONICET), Argentina.Established Investigator, CONICET.     

Selective kainic acid lesions in cultured explants of rat hippocampus

Summary The influence of the excitotoxin kainic acid (KA) on cultivated explants of rat hippocampus was investigated. Addition of 3 M KA to the culture medium over 24–48 h induced a destruction of the pyramidal cells in the CA3 region, whereas the CA1 pyramidal cells and the granule cells were left undamaged. Higher concentrations (10–100 M) of KA destroyed also the latter cell groups. The selectivity of the KA lesion at 3 M was further indicated by the fact that the acetylcholinesterase-positive neurons in the hippocampus were not destroyed through KA administration and that the stereoisomer dihydrokainic acid was ineffective in inducing lesions. Application of tetrodotoxin did not protect the CA3 pyramidal cells from KA lesion, whereas -glutamylaminomethylsulphonic acid (GAMS) only offered a very small, statistically not significant, protection. Baclofen protected the cultures slightly from KA lesions but not when added together with GAMS. Possible mechanisms responsible for the KA lesions in these cultures are discussed.Supported in part by a grant from the Swiss National Foundation for Scientific Research (No. 3.528.-0.83)     

Computers in radiology. Interfacing with peripheral devices

A fundamental part of building a computer system is control of and communication with peripheral devices. With use of graphics display terminals, video image digitizers, and array processors as examples, the basics of peripherals are discussed as they affect radiologic applications.     

A Healthy Life for African American Women Caregivers: A Concept Mapping Study

ObjectiveAfrican American women experience a higher burden of caregiving, but they are often underrepresented in studies on caregiver health. This study used a participatory process to elucidate how African American women caring for older adults view health and factors that influence health.MethodsWe invited African American women ages 24–64 years old who reported caring for an older adult for group concept mapping, a process consisting of five steps: 1) preparation, 2) idea generation, 3) sorting and rating, 4) creating maps, and 5) interpreting maps. Participants (n = 29) first completed idea generation by responding to the focus prompt “A healthy life for a caregiver includes _____.” Participants then sorted ideas into clusters based on conceptual similarity and rated each idea on desirability and importance. Data were managed via The Concept System Global MAX Software.ResultsIdea generation identified 512 ideas that reduced to 99 unique ideas. Using the 99 ideas, a cluster map with 12 outcome domains best fit the data. Identified clusters included spirituality, maintaining relationships, good character, taking action to cope, preserving oneself, support, personal empowerment, resources, striving for peace, handling emotions, wellness, and taking care of self and place. Forty-three ideas representing 10 of the 12 domains were rated high for desirability and importance.ConclusionA participatory research method was used to integrate the voices of African American women caregivers and provide a rich set of elements necessary for their health and well-being. We also identified potential focus areas for interventions aimed at promoting the health of these caregivers.     

Outcomes Research in Orthopaedics

A new agenda in outcomes research has developed in the past decade. The stimulus has come as the result of rapidly increasing health care costs, marked variations in utilization of health care services, and deficiencies in the research literature. Outcomes research includes methods such as analysis of large databases, small-area analysis, structured literature reviews (meta-analysis), prospective clinical trials, decision analysis, and guideline development. Clinical research should be prospective and should employ modern statistical and assessment methods. The focus of this research is on patient-oriented outcomes of care rather than on assessments of the process of care. To illustrate these applications in orthopaedics, lumbar spine fusion with internal fixation for "spinal instability" is presented as an example. Completed large-database analyses, small-area variation studies, and a meta-analysis indicate the need for clinical studies. An outline of the form and content of such a study is presented.     

Remission and relapse in subjects with panic disorder and panic with agoraphobia: a prospective short-interval naturalistic follow-up

This article reports on the course of uncomplicated panic disorder and panic with agoraphobia on 309 patients participating in the Harvard/Brown Anxiety Research Project, a prospective longitudinal study of patients with DSM-III-R-defined anxiety disorders. At 1 year, there was a .39 probability of full remission for uncomplicated panic disorder and a .17 probability of full remission for panic disorder with agoraphobia Similar differences in time to remission for these syndromes were still found when criteria for remission were made less stringent. However, even requiring less improvement for remission left a large percentage of subjects in an episode, and for those that remitted, relapse occurred quickly, indicating a chronic and recurrent course of illness. This is the first longitudinal, prospective, naturalistic study on a large cohort of subjects with anxiety disorders to have regular, structured, short-interval follow-up. Our results are consistent with the view that panic disorder has a chronic course with high rates of relapse after remission and longer episodes when agoraphobia is a part of the constellation of symptoms.     

Non-insulin-dependent diabetes mellitus and hypertriglyceridemia impair lipoprotein metabolism in chronic hemodialysis patients

Patients with diabetes mellitus undergoing chronic hemodialysis treatment have the worst outcome on dialysis due to an increased rate of cardiovascular complications. Nearly all patients present with dyslipidemia, a prominent vascular risk factor, probably responsible for the high rate of vascular injury. Since both uremia and diabetes predispose to hypertriglyceridemia, the present study was conducted to investigate the influence of diabetes mellitus and/or hypertriglyceridemia on lipoprotein metabolism in hemodialysis patients. LDL was isolated and characterized from hyper- and normotriglyceridemic diabetic and nondiabetic hemodialysis patients (n = 40; 10 in each group); also, LDL-receptor-dependent uptake and intracellular cholesterol metabolism were studied in HepG2 cells. In addition, scavenger-receptor-mediated uptake was examined in mouse peritoneal macrophages. LDL isolated from nondiabetic normotriglyceridemic hemodialysis patients exhibited impaired cellular uptake via the LDL receptor. Additionally, intracellular sterol synthesis was less inhibited and cholesterol esterification was reduced compared with LDL from healthy control subjects. Reduction of catabolic capacities was more marked in hemodialysis patients who were either diabetic or hypertriglyceridemic and even more pronounced in patients presenting with a combination of both diabetes and hypertriglyceridemia. Hypertriglyceridemic and diabetic patients showed reduced lipase activity and increased LDL oxidation. Furthermore, they accumulated a fraction of small, dense LDL, and LDL was predominantly taken up via the scavenger-receptor pathway in peritoneal macrophages. This study elucidates the distinct influence of diabetes and/or hypertriglyceridemia in hemodialysis patients on cellular LDL metabolism via specific and nonspecific metabolic pathways. Furthermore, it underscores the cumulative impact of these pathologic entities on impairment of lipoprotein metabolism and increase of cardiovascular risk.     

Why does postpsychotic IQ decline in childhood-onset schizophrenia?

OBJECTIVE: The authors' goal was to examine whether the postpsychotic decline in full scale IQ during adolescence for patients with childhood-onset schizophrenia is due to a dementing process or simply failure to acquire new information and skills. METHOD: Linear regression was used to determine the rate of change for scaled and raw scores on subtests of 31 patients with childhood-onset schizophrenia. The resulting slopes were examined and related to changes in the patients' brains determined by magnetic resonance imaging. RESULTS: Three postpsychotic subtest scaled scores declined significantly: picture arrangement, information, and block design. In contrast, there was no decline in the non-age-corrected (raw) scores for any subtest. A significant correlation was found between decrease in hippocampal volume and a smaller increase in raw score on the information subtest. CONCLUSIONS: The decline during adolescence in the full-scale IQ of patients with childhood-onset schizophrenia does not reflect dementia but, rather, an inability to acquire new information and abilities.