Perseverative neural processes and consolidation of the memory trace.

Perseveration theory as a behavioral theory of retroactive inhibition has generally lost favor and has been replaced with the concepts of associative interference. Various experimental approaches to inducing retrograde amnesia and recent evidence to support the existence of a system within the brain responsible for the permanent fixation of memory traces indicates that the application of available physiological procedures offers a promising approach to defining the structures involved in the fixation of memory traces. From Psyc Abstracts 36:02:2CL18G. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dopamine-dependent frontostriatal planning deficits in early Parkinson's disease.

Three groups of medicated and nonmedicated patients at different stages of Parkinson's disease and a group of neurosurgical patients with localized frontal lobe excisions were assessed on 2 novel tests of planning and spatial working memory. Results demonstrate that, like other tests of frontal lobe dysfunction, planning and spatial working memory are vulnerable in nonmedicated patients with mild Parkinson's disease and suggest that certain aspects of the planning impairment in these patients may be ameliorated by dopaminergic therapy. Specifically, with medication there was an improvement in accuracy of planning, but not in latency, in a series of problems based on the Tower of London test of planning. The results in terms of the frontostriatal, dopamine-dependent nature of some of the cognitive deficits found in early Parkinson's disease versus the apparent dopamine-independent nature of deficits in other cognitive processes are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dopamine-dependent cyclic AMP generating system in chick retina and its relation to melatonin biosynthesis

Stimulation of a D4-like dopamine (DA) receptors inhibits a cAMP-dependent increase in serotonin N-acetyltransferase activity and melatonin biosynthesis in the chick retina. In order to gain more insight into the molecular mechanisms underlying this suppressive action of DA, the effects of selective stimulation of the D2-family of DA receptors (including the D4-subtype) on cAMP formation were examined in chick retina using two experimental approaches: measurements of adenylyl cyclase activity in retinal homogenates, and cAMP accumulation in eye cup preparation prelabeled with [3H]adenine. The DA-sensitive adenylyl cyclase system is well expressed in chick retina. DA increased both basal and forskolin-stimulated adenylyl cyclase activity. This effect of DA was antagonized by SCH 23390 (a blocker of D1-family of DA receptors) and not affected by sulpiride (a D20-family blocker). Incubation of retinal homogenates with quinpirole (a predominant agonist of D3/D4 DA receptor subtypes) did not produce any major changes in adenylyl cyclase activity. On the other hand, activation of D4-like DA receptor subtype by quinpirole decreased forskolin-stimulated cAMP formation in intact chick retina maintained in "eye-cup" preparations. It is suggested that D4-like DA receptors regulating melatonin biosynthesis in chick retina may be indirectly linked to the cAMP generating system.     

Think before you speak: Pauses, memory search, and trace redintegration processes in verbal memory span.

Immediate memory span and speed of memory search were assessed for words and nonwords of short and long spoken duration. Memory span was substantially greater for words than for nonwords and for short than for long items, though speed of memory search was unaffected by either length or lexicality. An analysis of the temporal pattern of responses in the memory span task indicated that inter-item pauses were longer between nonwords than words but that these pause durations were unaffected by item length. A model of verbal short-term memory span is described in which trace selection from a short-term store and the redintegration (restoration) of degraded phonological traces both occur in the pauses between saying successive items. Both trace selection and trace redintegration appear to play important roles in accounting for individual differences in memory span. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of the somatic region of the cortex on trace inhibitory processes in the posterior lateral nucleus of the thalamus

Acute experiments were conducted on cats under nembutal anesthesia. A study was made of the dynamics of the changes occurring in the curve of restoration of the test response amplitude in the thalamo-cortical fibers to the pared stimulation of the medial lemniscus with various actions on the somatosensory ared. The curve under study served as an indicator of the corticofugal influences on the inhibitory after process in the transmission nucleus of the thalamus. The influences on one somatosensory area of the cortex blocked the transmission of the afferent signals in 70% of the neurons of the transmission nucleus of the thalamus. A correlation between the number of the neurons participating in the reaction and the character of the initial phase of the inhibitory afterprocess was noted.     

Health economics and clinical pathology

A 3-y-old child ingested SUCCIMER capsules to receive a dose of 185 mg dimercaptosuccinic acid/kg body weight. No adverse effects occurred.     

Atmospheric trace chemicals

This paper deals with the important trace-materials in the natural and anthropogenetic influenced atmosphere. They exist as gases as well as solid and solid-fluid particles. They are significant for numerous physical processes in the atmosphere and have also a direct influence on our biological environment.     

Liver allograft pathology

Complications following orthotopic liver transplantation are often difficult to differentiate from each other. Based on their experience with more than 1,800 transplantations, the authors strive to describe the varied histologic appearances of allograft injuries and how they differ.     

Biology and pathology of the mitochondrion

The mitochondrion is a highly efficient organelle that is essential for the function of cells. It is currently accepted that mitochondria originated from primitive nonphotosynthetic bacteria that were engulfed by early eucharyotic cells. Most of the normal and pathologic interactions between mitochondria and the cells that contain them can be viewed as symbiotic processes. The main features of mitochondrial structure and function and some of the pathological disorders that involve this organelle are reviewed.     

Occupational pathology: present and future

Formed 75 years ago, occupational pathology has defined structure of occupational morbidity, determined principles of occupational diseases' pathogenesis and pathomorphosis, demonstrated dependence of occupational entities on acting occupational hazards, described clinical manifestations of occupational diseases, emphasized informative diagnostic complexes. Diagnosis in occupational pathology now is established on basis of etiology. Manifold activities helped to form a system preventing health disorders caused by occupational hazards. Topical problem is to elaborate and put into practice some criteria for compensation of occupational damage with differential expert assessment of functional disorders caused either by occupational disease or by general one. Prospective trend could be to create a system organizing and managing workers' health on workplace and to put "protection by time" principle into practice with forecasting risk of occupational diseases and dose-effect dependence. Another prospect is to elaborate and put into practice a training in social and psychologic adaptation for occupational managers and industrial workers.