Somatostatin Receptor 2 Expression in Canine Meningioma.

The neuropeptide somatostatin (SST) plays an important regulatory role in the proliferation of normal and neoplastic cells. Five subtypes of somatostatin receptors (SSTRs), SSTR1-SSTR5, have been identified in human tumours. The SSTR2 subtype is identified most commonly in meningiomas. Long half-life SST analogues are now recommended for the systemic treatment of unresectable or radiation-refractory recurrent human meningiomas. In this study, SSTR2 expression was evaluated in 46 canine meningiomas; in 21 cases this was by immunohistochemistry and in 25 cases by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). In addition, SSTR2 expression was evaluated by immunocytochemistry, western blotting and RT-qPCR on primary cell cultures prepared from two canine meningiomas. SSTR2 immunohistochemical expression was observed in 17/21 cases (81%), and SSTR2 mRNA expression was detected in 14/25 cases (56%). SSTR2 protein and gene expression were not significantly correlated with the tumour histological subtype or grade. Overall, meningothelial meningiomas showed constant and diffuse SSTR2 immunohistochemical expression and the highest SSTR2 gene expression level compared with other subtypes. A tendency for loss of SSTR2 in high-grade meningiomas was observed in both immunohistochemical and RT-qPCR studies. About 90% of cultured canine meningioma cells showed SSTR2 expression. In both of the meningioma cell cultures, SSTR2 expression was also detected by western blotting and RT-qPCR. This study demonstrates for the first time that canine meningioma expresses SSTR2 and that this expression is maintained in vitro. Our results, while preliminary, provide encouragement for further studies aimed at finding novel medical treatment strategies for canine meningioma, especially for tumours that are not surgically accessible.

Dissociation between recency and span: neuropsychological and experimental evidence.

This article reports dissociations between verbal span and the recency portion of the serial position curve in immediate free recall, in 2 neuropsychological case studies and in 3 experiments with normal participants. Patient A. N. presented with an impaired serial verbal span while showing an intact recency effect. The opposite pattern was observed in patient G. C., who despite a poor recency showed normal span in verbal serial recall tasks. Experiments 1 and 2 showed a recency effect with visually and auditory presented lists and written recall was resistant to the effects of articulatory suppression and of irrelevant speech, but was disrupted by the suffix effect. Experiment 3 showed that in contrast with recency, memory span was affected by articulatory suppression and irrelevant speech during presentation but not by a suffix. These findings are not consistent with the idea that span and recency measure aspects of the same memory system. Moreover, in clinical practice, they should not be used as equivalent alternatives.

Frontal lobe functioning in man: the riddle revisited.

Forty-eight patients, each with a single frontal lobe lesion, were tested with a battery of 10 of the most widely used neuropsychological tests, comprising five traditional "frontal" tests and five others, for which that claim is not generally made. All correlations among the tests in the group were positive and significant. Moreover, the average correlation between each frontal test and the other tests in the frontal group was found to be higher than the average correlation of the same frontal test with the tests in the other group. A factor analysis of the scores on the five frontal tests yielded a single factor accounting for 53% of the variance. A factor analysis on the entire battery of tests (frontal plus nonfrontal) also yielded a strong general factor; although this accounted for a smaller portion (43%) of the shared variance, and one test (Verbal Span) failed to show a substantial loading on the factor. Neither the results of the present study nor the findings of other researchers argue for the abandonment of the concept of "executive" functioning, mediated by the functioning of the frontal lobes, in favor of a variant of fractionation.

Recovery of object recognition in a case of simultanagnosia.

A case of visual agnosia is described. The patient, V C, complained of difficulties in identifying visual stimuli, after a stroke in the left occipital lobe. A neuropsychological examination demonstrated a range of symptoms consistent with (ventral) simultanagnosia, and a reaching disorder--suggesting Balint's syndrome. The patient's object recognition ability improved considerably over time.

Poppelreuter-Ghent's Overlapping Figures Test: its sensitivity to age, and its clinical use.

This study aims to identify the cognitive variables involved in a task of visual recognition of meaningful and meaningless two-dimensional line-drawings of shapes; the Poppelreuter-Ghent Overlapping Figures Test. It was found that the performance of healthy controls was influenced by age and education, but not sex. Age and education adjusted norms are set forth. Meaningful patterns were better recognised than meaningless ones. Number of overlapping patterns, direction, and degree of rotation were among the other variables considered. Only the latter variable significantly influenced the difficulty of the task. The clinical use of this test was verified on clinical populations of patients affected by Alzheimer's disease and right or left hemisphere damage. Left hemisphere damaged patients did not show deficits. Alzheimer and right hemisphere damaged patients were impaired and the degree of rotation significantly influenced their performance. In conclusion, the Poppelreuter-Ghent's Test is a multicomponential task, the visuo-spatial components of which were shown to be the most important.

Living and non-living categories. Is there a "normal" asymmetry?

A picture naming task and a semantic memory verbal questionnaire were given to normal subjects to assess the possible asymmetry between knowledge for non-living and living things. We first examined 60 elderly subjects with low education. Asymmetry between non-living and living things was found in the semantic knowledge questionnaire and living things fared worse. This difference was not explained by discrepancy in item frequency, familiarity or prototypicality. Using the same questionnaire, we analysed difficulty judgements given by younger, better-educated subjects: questions about living things were slightly, but significantly more difficult than questions regarding non-living things. In order to check for a possible sample bias, we submitted another verbal questionnaire with an analogous structure to different judges and replicated the previous results. These findings are discussed with regard to the selective semantic memory deficit for living things observed in patients. We suggest that the cognitive pattern presented by these cases may be linked to, but not fully explained by the greater difficulty living things present for normal subjects.

Autobiographical recollection and frontal damage.

A neuropsychological experiment on autobiographical retrieval of incidental past events, checked by means of a standardized enquiry, was carried out on a series of 16 patients with CT-assessed frontal lobe lesions. Of 16 patients, six were impaired on autobiographical retrieval. Moreover, eight were impaired on supraspan verbal learning. Impairment on both resulted in three patients, whereas in five there was no impairment on either test. Concordance between autobiographical and learning impairment was far from significant. Poor autobiographical retrieval correlated significantly with "executive" test performances and with the CT-verified bilaterality of the frontal damage. Poor learning of new information did not correlate significantly with "executive" performances, nor did it appear to be related to the hemispheric side or to the bilaterality of the frontal lesion. We propose that the relationship between the attentional system of retrieving from remote memory and of learning new information is qualitatively different.