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.     

Behavior of horizontal semicircular canal afferents in alert monkey during vestibular and optokinetic stimulation

Summary The behavior of single vestibular nerve fibers from the lateral semicircular canal was recorded during sinusoidal oscillations of the head, during optokinetic stimulation with the head stationary, and during spontaneous oculomotor behavior in the alert monkey. The response of similar fibers to adequate vestibular stimulation was also studied in some of the animals under deeply anesthetized conditions. In the alert animals all units were spontaneously active and their discharge was modulated only by adequate vestibular stimulation. Ipsilateral horizontal rotations of the head were excitatory for all units. No modification of this basic vestibular response by visual stimulation including full-field striped drum rotation was observed. Furthermore no correlation of unit activity with oculomotor function including voluntary saccadic and pursuit eye movements was found in any of the units. The regularity of spontaneous discharge was the most consistent characteristic that differentiated the unit response into types. Most units were very regular in discharge, but a few were very irregular. The averaging of unit discharge over several cycles of oscillatory head rotation showed that the irregular type units were also consistently modulated by adequate vestibular stimulation. Both regular and irregular type units were found in the anesthetized animals. Unimodal distributions of the quantitative values for unit resting discharge rate, sensitivity, and phase relationship were found. The distributions for these three parameters were similar in the units recorded in the anesthetized animals. Thus at least these characteristics of semicircular canal response seem not to be affected by the vestibular efferent system which should be altered or eliminated in the case of the anesthetized animals.Research supported by NIH Grant EY0995-04.     

Safety of injectable autologous human fibroblasts

Autologous dermal fibroblasts after propagation in cell culture were used for face soft tissue augmentation. Twenty patients aged 37–61 years with facial rhytides and atrophic scars were treated with autologous fibroblasts from cell culture. Significant sustained clinical improvement was observed. Cells of early passages (4, 5, 6) were used for injection. The study showed that cultured fibroblasts were functionally active and produced large quantities of type I collagen.In vitro studies of scar formation potency of injectable fibroblasts showed that these cells possessed normal collagen gel contraction capacity.In vivo experiments showed that cultured fibroblasts exhibited no oncogenic properties and induced no tumors in nude mice. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 130, No. 8, pp. 203–206, August, 2000     

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.     

Effects of methylphenidate (Ritalin) on auditory performance in children with attention and auditory processing disorders.

A double-blind, placebo-controlled study was used to investigate the effects of methylphenidate (Ritalin) on tests of auditory processing in children diagnosed with both Attention Deficit Hyperactivity Disorder (ADHD) and Central Auditory Processing Disorder (CAPD). Thirty-two subjects received three Central Auditory Processing (CAP) tests and the Auditory Continuous Performance Test (ACPT), a measure of attention/impulsivity, at two separate test sessions: once when medicated with Ritalin and once when nonmedicated (placebo). Sixteen subjects were assigned randomly to receive their medication first and 16 to receive the placebo first. A counterbalanced 2 x 2 mixed factorial analysis of variance was conducted for each of the four dependent variables: Staggered Spondaic Word (SSW), Phonemic Synthesis (PS), Speech-in-Noise (SN), and ACPT measures. Analyses revealed that Ritalin did not have a significant effect on any of the three CAP measures. However, ACPT performance was significantly better (p < .000) for the Ritalin versus placebo condition.