Electroencephalographic studies in workers exposed to solvents or pesticides.

The qEEG was studied in groups of young and old workers exposed to solvents (house and industrial painters) and in a group of workers exposed to pesticides. Three methods were used: a quantified visual scoring system, the neurometrics method and a multivariate analysis of mean frequencies. Using the visual assessment as well as the neurometrics method, the older painters showed more abnormalities than the younger painters and the pesticide exposed workers. The "profile" of abnormalities differed in all 3 groups. Changes of the mean spectral frequencies were mainly found in the subjects exposed to pesticides. In this study we concluded that the neurometrics method can be useful in neurotoxicological studies. With this technique minor changes in electrocortical function can be detected in seemingly normal workers. However, frequency parameters should be added to the power measures which are usually studied.     

Prevalence of hereditary ataxias and spastic paraplegias in Molise,a region of Italy

Summary An epidemiological survey of hereditary ataxias and paraplegias was conducted in Molise, a region of Italy (335, 211 inhabitants on 1 January 1989). Total prevalence was 7.5 x 10^–5 inhabitants (95% confidence limits 4.8–11.1). There were 7 patients with Friedreich's disease, 5 with early onset cerebellar ataxia with retained tendon reflexes, 4 with ataxia-telangiectasia, 9 with hereditary spastic paraplegias (2 autosomal dominant and 7 autosomal recessive cases). There was no patient with autosomal dominant cerebellar ataxia.     

The AIDS Pandemic: A Nursing Model

The pandemic of acquired immunodeficiency syndrome (AIDS) calls for global cooperation to develop strategies for interventions both to prevent the disease and to care for persons with it. The conceptual framework "Health for all: A model for nursing's contributions" provides guidance for the processes of assessment, diagnosis, planning, implementation of care, and evaluation of mortality and morbidity related to AIDS. The disease challenges the biologic, sociologic, medical-technical, and environmental determinants as they affect health. Specific recommendations for health care interventions are relevant to each determinate, with community health status as the focus.     

The regional distribution of adenosine-regulating enzymes in the left and right ventricle walls of control and hypertrophic heart

Summary The transmural distribution of the adenosine-generating enzyme 5-nucleotidase (5N) and of the adenosine-degrading enzymes adenosine deaminase (ADA), AMP deaminase (AMP-D) and adenosine kinase (Ado-K) were determined across the walls of left and right ventricles of control and hypertrophic rat hearts.The enzyme distribution across the left ventricle wall (but not across the right wall) of normal hearts was not uniform: 5N activity shows its highest levels in the subepicardial and in the subendocardial regions, whereas all the other enzyme activities show their lowest levels. A similar pattern of transmural distribution was also detected in other mammalian species (ox and pig).In the experimental cardiac hypertrophy, caused by two different types of chronic cardiac overload, the levels and the profiles of transmural distribution of 5N and ADA enzyme activities may significantly change across the rat left ventricle wall.     

Memory performances after anterior communicating artery aneurysm surgery

10 patients operated on for anterior communicating artery aneurysm (ACoA) underwent to neuropsychological examination one year after surgery, in order to detect eventual behavioural and/or amnestic disorders, already described by others in a wide percentage of such patients. Even if after accurate neurological examination the therapeutic results were defined as "good", 60% circa of our patients present amnestic and/or behavioural disturbances. Possible correlations between neuropsychological tests finding and intraoperative occurrences (early aneurysm rupture, gyrectomy etc.) are considered and discussed.     

Marked locomotor stimulation in monoamine-depleted mice following treatment with atropine in combination with clonidine

Summary The present study demonstrates that the muscarinic antagonist atropine and the -adrenergic agonist clonidine, though ineffective when administered separately, produced a pronounced locomotor stimulation in monoamine-depleted mice when combined. The atropine + clonidine-induced locomotor stimulation was counteracted by both the ₂-adrenoceptor antagonist idazoxan and the acetylcholinesterase inhibitor physostigmine. Thus, it is clear that simultaneous manipulations with cholinergic and adrenergic systems are as effective in restoring locomotion in monoamine-depleted mice as increasing central dopaminergic tone. This finding may have implications for the treatment of a movement disorder like Parkinson's disease.     

Involvement of D1 and D2 Dopamine Receptors in the Control of Horizontal Cell Electrical Coupling in the Turtle Retina

We studied the actions of D1 and D2 dopamine agonists and antagonists on the coupling of horizontal cell axons in the turtle retina by a combination of pharmacological and electrophysiological methods. Both D1 and D2 receptors were identified in membrane fractions by radioligand binding using [3H]-SCH 23390 and [3H]-spiperone, respectively. The KD of both receptor classes were identical (0.21 nM) but D1 receptor density exceeded that of D2 receptors by more than four-fold. D1 agonists increased the activity of adenylate cyclase in a dose-dependent manner, whereas D2 agonists were without significant effect by themselves, nor did D2 antagonists block the D1-mediated increase in adenylate cyclase activity. Intracellular recordings and Lucifer Yellow dye injections were used to characterize the modifications of the receptive field profile of horizontal cell axons (H1AT) exposed to different pharmacological agents. Dopamine or D1 agonists (0.05 - 10 microM) induced a marked constriction of the H1AT receptive field, whereas D2 agonists elicited a small expansion of the receptive field. However, in the presence of a D1 antagonist, as well as IBMX to inhibit phosphodiesterase, D2 agonists (10 - 70 microM) induced a marked increase in the receptive field profile. These results indicate that both D1 and D2 dopamine receptors play a role in shaping the receptive field profile of the horizontal cell axon terminal in the turtle retina.     

Aspects of three dimensional reconstruction for a multi ring positron tomography

An important feature of multi ring positron tomographs is the inter plane septa, the purpose of which is to reduce random and scattered coincidences. In general, such septa also eliminate the coincidence lines of response between pairs of detectors more than one ring apart. The operation of a camera without septa must result in an increase not only in the true coincidence rate, but also in the singles, and therefore in the dead time and randoms rate, and in the scattered coincidences. A configuration option in the coincidence hardware of the 8 ring, 15 slice ECAT 931/08-12 enables a full set of 64 sinograms to be acquired when the septa are removed. The detector normalisation and transmission data for studies with the septa out can be obtained using a rotating pin source. To take maximum advantage of the additional signal, the emission data must be reconstructed using a fully three dimensional reconstruction algorithm. This paper presents an analysis of some phantom studies acquired without septa and reconstructed in three dimensions. The results are compared with data acquired with septa for the same phantoms imaged under similar conditions. It is found that, with the septa removed, the signal to noise for a uniform, 20 cm diameter cylinder improves by a factor of 2.8 in the centre of the field of view, whereas in regions distant from the centre in the axial direction, the signal to noise decreases due to the increase in scatter and randoms. An improvement in signal to noise is observed in 6 cm of the 10 cm axial length of the tomograph.This article was presented at the 1st EEC workshop on accuracy determination in PET, January 19–20th. 1989 Pisa, Italy (COMAC-BME Concerted Project Characterization and Standardization of PET Instrumentation)     

Interaction between clonidine and physostigmine in normal rats and in rats after sinoaortic denervation

Summary Clonidine (3–30 g · kg^–1, i.v.) induced a fall in mean arterial pressure in rats after sinoaortic denervation but not in sham-operated animals. Moreover, sinoaortic denervation reduced the bradycardic action of this antihypertensive drug. Pressor and tachycardic response to physostigmine (60 g · kg^–1, i.v.) were greater in denervated than in sham-operated rats. The increase of mean arterial pressure was 26.2 ± 2.2 mm Hg in sham-operated rats (n = 12) and 53.8 ± 2.0 mm Hg in denervated rats (n = 12, P < 0.005).Pretreatment with 3 g · kg^–1 (i. v.) of clonidine did not alter the pressor response to physostigmine (60 g · kg^–1) in either of the two groups; 10 and 30 g · kg^–1 of clonidine reduced the physostigmine-induced increase of mean arterial pressure in sham-operated rats but enhanced the pressor response in denervated animals. Furthermore, an ineffective dose of physostigmine (30 g - kg^–1 i.v.) induced a pressor response after pretreatment with clonidine (10 gg · kg^–1) in denervated rats.Clonidine (10 g · kg^–1) did not affect the pressor effect of 1,1 dimethyl-4-phenylpiperazinium iodide (DMPP: 50 g · kg^–1 i.v.) or phenylephrine (4 g · kg ^–1, i.v.) in either group.The anticholinergic effect of clonidine in sham-operated rats may be explained by an inhibitory action on the release of acetylcholine in several brain structures but the facilitatory effect of clonidine observed in denervated animals is not clear. The results did not suggest a peripheral involvement in this facilitatory effect. Send offprint requests to M. A. Enero at the above address     

Enhanced metabolic activation of chemical hepatocarcinogens in woodchucks infected with hepatitis B virus

The metabolism of chemical carcinogens was investigated in liverpreparations from 28 captive woodchucks (Marmotamonax). Of these,23 were naturally infected with the wood-chuck hepatitis virus(WHV), and eight also had primary hepatocellular carcinoma (PHC).Twenty-nine parameters were investigated in liver subcelhilarfractions, including cross-reactivity with HBsAg, and biochemicalparameters, such as -glutamyl transpeptidase, cytochrome P-450and mirosomal monooxygenases (aryl hydrocarbon hydroxylase,ethodycoumarin and ethoxyresorufin deethylases, amino-pyrineand dimethylnitrosamine demethylases, and testosterone 7-and16ß- and 6ß-hydroxylases), uridine 5'-diphos-phoglucuronosyltransferase, GSH and related enzymes (peroxidase, reductaseand S-transferase), as well as other cytosolic enzyme activities(glucose 6-phosphate and 6-phosphogluconate dehydrogenases,NADPH- and NADH-dependent diaphorases, and DT diaphorase). Inaddition, liver preparations were used in order to quantifythe metabolic activation into bacterial mutagens of five procarcinogens(aflatoxin B¹, the pyrolysis products Trp-P-2 and MelQ, 2-aminofluoreneand dimethylnitrosamine) and the decrease of potency of threedirect-acting mutagens (sodium di-chromate, ICR 191 and 4-nitroquinoline1-oxide). WHV infection produced a significant stimulation ofcarcinogen metabolism, as shown by the simultaneous change indetoxification parameters (GSH depletion) and activation indices(enhancement of microsomal monooxygenases and of pro-carcinogenactivation into mutagenic metabolites). There were no significantdifferences between WHV-positive samples from animals, withoutPHC and the noncancerous tissue of PHC-bearing animals, whereasa decrease of both activation and detoxification indices wasrecorded in the turmorous tissue. There was a considerable interindividualvariability among WHV carriers, which was tentatively ascribedto genetic factors. Pregnancy was the only known factor influencingthe results in WHV carriers. However, even by excluding pregnantanimals, the effects on carcinogen metabolism produced by WHVinfection were still statistically significant. These results,together with previous data obtained in humans, revealed thatmetabolic factors may play a role in the synergism between viralhepatitis and chemical hepato-carcinogens in the etiopathogenesisof PHC.