Influence of the blockade of D2 dopamine receptors of the cat neostriatum on the baseline activity and saccadic eye movement-associated reactions of neurons of the reticular portion of the substantia nigra

The activity of neurons of the reticular portion of the substantia nigra before and after the microinjection of haloperidol (25 μg/5 μl) into the head of the caudate nucleus on the ipsilateral side was investigated under chronic experimental conditions in cats, using the extracellular microelectrode pickup technique. A significant (p<0.05) increase, from 34 to 61%, of neurons with the burst type of spontaneous activity was established after the injection of haloperidol. A significant increase in the ratio of the number of excitatory responses to inhibitory responses, from 0.04 to 0.4, was identified among the reactions associated with saccadic eye movements following the microinjection of haloperidol. The number of orienting saccades in response to the visual stimulus decreased against this background from 58 to 37%. The identified changes are regarded as a result of the disinhibition of GABAergic neurons of the reticular portion of the substantia nigra under the influence of the blockade of D₂ dopamine receptors of the neostriatum. Department of the Physiology of the Cerebral Cortex and Subcortical Structures, A. A. Bogomolets Institute of Physiology, Academy of Sciences of Ukraine, Kiev. Translated from Fiziologicheskii Zhurnal irneni I. M. Sechenova, Vol. 80, No. 1, pp. 17–22, January, 1994.     

Progressive muscular atrophy variant of familial amyotrophic lateral sclerosis (PMA/ALS)

Twelve cases of adult-onset progressive muscular atrophy variant of amyotrophic lateral sclerosis (PMA/ALS) were studied in a small rural population of 1500 in the Republic of Belarus (former Soviet Union). The patients were members of three apparently related kindreds, each showing autosomal dominant pattern of disease inheritance. The average age at clinical onset ranged from 26 to 57 years (mean, 40 years). Each patient suffered from skeletal muscle weakness and wasting, starting in the limbs and spreading to the trunk and neck, with very limited bulbar and no upper motor neuron involvement. Death from respiratory failure occurred from 13 to 48 months (mean, 28 months) after first symptoms. Dramatically decreased number of spinal motor neurons was the most characteristic neuropathologic feature in two autopsied cases. Most of the remaining degenerating neurons contained intracytoplasmic hyaline inclusion bodies. A D101N mutation in exon 4 of the SOD1 gene was identified in a PMA/ALS patient and in one of her three unaffected children. Our data support the view that some subtypes of familial ALS associated with SOD1 mutations may present as PMA. Diagnostic criteria of ALS should be accordingly modified to include the PMA variant of familial ALS.     

Prognostic significance of pathological and biological factors in hepatocellular carcinoma

Prognostic factors in hepatocellular carcinoma (HCC) conventionally consist of staging with the tumour node metastasis system and grading by tumour cellular differentiation. There are also other factors useful in prognostication but most of them are clinical. With new discoveries in the pathobiology of cancers and introduction of new medical technology, pathological and biological factors of HCC in relation to prognosis have been studied quite extensively. Morphological features of the tumour, both gross and histological, have been found to be significantly related to tumour recurrence and patient survival. Recently, applications of new antibodies and techniques have enabled studies on cellular proliferation using different antibodies such as those for proliferating cell nuclear antigen and Ki-67 protein. These studies on cellular proliferation, as well as assessment of argyrophilic nucleolar organizing regions, have been shown to provide good prognostic significance. Flow cytometric studies on DNA ploidy and studies on expression of genes including the p53 gene, hormone receptors and others show less unanimous results in their prognostic significance. The influence of gender on survival is also reviewed. In conclusion, pathological and biological factors are useful and help to guide clinicians in the management of patients and in assessment of long-term prognosis.     

Participation of the visual projection and association cortical inputs in the formation of responses of neostriatal responses to visual stimuli in the alert cat

Extracellular responses of caudate neurons to local light stimuli and to electrical stimulation of specific (area 17) and associative (the Clare-Bishop area) cortical zones were studied in awake cats. Stimulation of the Clare-Bishop area was found to be more effective for caudate cell responses in comparison with stimulation of area 17; it influenced more caudate cells (47%), whereas responses to area 17 stimulation occurred only in 8% of investigated cells. The mean latency values also were lower in the first case. Only a few neurons responded to stimulation of the both areas. Responses to visual stimuli and to electrical stimulation of these cortical areas were compared in the same caudate cells. Neurons which responded to visual stimuli were also better activated by the Clare-Bishop stimulation than by stimulation of area 17. Such cells were distributed preferably in the body of caudate nucleus. The possible role of the Clare-Bishop area in transmission of visual information to neostriatum is discussed.