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Biomedical subjects

I Appollonio

Publications and source records attributed to I Appollonio.

16 recordsLinked to original sources
PubMed1995

Sensory impairments and mortality in an elderly community population: a six-year follow-up study.

Previous studies have shown that sensory impairments adversely affect the quality of life of elderly people, but have failed to demonstrate consistent results on mortality. We examined the predictive value of hearing and visual impairments on mortality in an urban population of 1140 non-institutionalized elderly subjects, aged 70-75 years. Baseline information was collected in 1986 through a door-to-door interview with a standardized questionnaire and the sensory assessment was performed using bedside tasks: the whispered voice test for hearing and the Snellen chart for vision. Overall mortality rate at 6 years was 25.5%, with a significant sex difference (males = 37.5%; females = 19.8%) and a significant interaction between sex and sensory impairment. Bivariate logistic regression showed that hearing deficit was associated with a significant increase in mortality risk only in the men. This increase remained significant even after control for the demographic variables and the global physical health status. Multivariate logistic regression showed that the effect of hearing deficit on mortality was mediated by psychosocial parameters (mood and social relationships level). Sensory assessment through simple bedside tests should become part of the routine clinical evaluation of elderly people.

Activities of Daily Living↗
PubMed1994

Implicit and explicit memory in patients with Parkinson's disease with and without dementia.

OBJECTIVE: To study explicit and implicit memory processes in patients with Parkinson's disease. DESIGN: Case-control design. All subjects were given a neuropsychological test battery, and the test scores were compared among the groups. SETTING: Government-funded research facility. All subjects were examined as outpatients. PATIENTS: We tested nondemented (n = 13) and demented (n = 5) patients with Parkinson's disease and normal controls (n = 12) matched for age, gender, and educational level. MAIN OUTCOME MEASURES: Memory for verbal and pictorial stimuli under both explicit and implicit retrieval conditions. RESULTS: Both nondemented and demented patients with Parkinson's disease exhibited impairment on tests of explicit memory. Their impairment could be graded based on the level of effort required by the task: impaired free recall in nondemented patients and impaired free recall, cued recall, and recognition in demented patients. By contrast, neither group showed evidence of impairment on automatic (modality monitoring and word frequency estimation) or implicit (word and picture fragment identification) memory tasks. Correlation analyses did not support any association between the effortful memory deficits and neurologic variables, mood, or performance on executive function tests. CONCLUSIONS: Memory deficits in patients with Parkinson's disease primarily involve the conscious, effortful strategic aspects of searching long-term memory.

Aged↗
PubMed1994

Magnetic resonance imaging functional activation of left frontal cortex during covert word production.

Six normal volunteers underwent 4-T functional magnetic resonance imaging while performing a covert letter fluency task. An echo planar imaging sequence was utilized to detect activation based on deoxyhemoglobin contrast. All 6 subjects showed consistent activation in the frontal operculum and premotor and primary motor cortices. Activation was also detected in the supramarginal gyrus and the posterior part of the superior temporal gyrus. These results show that magnetic resonance functional neuroimaging can be used to investigate cerebral activity noninvasively during performance of complex cognitive tasks.

Adult↗
PubMed1994

No specific effects of caloric stimulation on the visual-imagery processes of normal subjects.

Recent research indicates that neglect can be temporarily, but only partially, ameliorated by activating the contralateral hemisphere via caloric stimulation and other techniques. In this study, we evaluated whether caloric stimulation could be used to manipulate visual-imagery processes in normal subjects. 11 normal subjects participated in a quantitative visual-imagery task while undergoing caloric stimulation. Neither side of report nor ear of caloric stimulation affected performance. Possible reasons for this negative result are reviewed.

Adult↗
PubMed1993

Assessment of reliability and biological significance of glutamate levels in cerebrospinal fluid.

The published information on glutamate levels in cerebrospinal fluid (CSF) and modifications in neurological disorders is controversial. In the present study, we demonstrated a metabolic instability of glutamate in untreated CSF and a spurious elevation of its levels by the current methods of CSF acidification. These findings may explain the discrepancies observed with different methods of CSF processing and analysis. We suggest a method of inactivating CSF enzymes that yields stable glutamate levels under different storage conditions. Use of such a method may be necessary for clinical studies.

Acids↗
PubMed1991

Acute noise stress in rats increases the levels of diazepam binding inhibitor (DBI) in hippocampus and adrenal gland.

We investigated the effect of acute noise-induced stress on the concentrations of diazepam binding inhibitor (DBI) and its processing products in brain regions and adrenal glands of rats. DBI levels in hippocampus began to increase at 15 and 30 min and became significantly higher (+100%) at 90 and 120 min after stress; they returned to normal values at 360 min. While basal DBI levels were similar in the left and right hippocampus, the stress-induced increase of DBI levels was significantly higher in the left compared to the right side. A significant increase was also detected in the adrenals; here, the time course of DBI increase paralleled that of previously reported plasma corticosterone in stressed rats, being significantly higher 30 min after stress, and recovering to normal values at 60 and 90 min. After acute noise-induced stress, no significant change of DBI levels was detectable in cerebral cortex, striatum, hypothalamus and cerebellum. The present study reports for the first time the occurrence of a modification of DBI and its processing products (ODN-like immunoreactivity) in an experimental model of stress, and suggests a role for these neuropeptides in emotional responses.

Adrenal Glands↗
PubMed1990

Characterization of peripheral benzodiazepine receptors in human blood mononuclear cells.

In the present study, peripheral-type benzodiazepine receptors in human circulating mononuclear cells were characterized, using [3H]PK 11195 as specific ligand. The specific binding was saturable, with a Bmax of 14 pmol/mg protein and a Kd of 7 nM. The pharmacological characterization, using different displacing drugs, indicated a mitochondrial type of peripheral benzodiazepine receptor since it was not coupled to the GABA receptor and was displaced by protoporphyrin IX. These data indicate that human circulating mononuclear cells possess benzodiazepine recognition sites, similar to non-neuronal receptors. The role of these receptors and possible modifications in different diseases need to be investigated.

Adult↗
PubMed1990

Decreased density of benzodiazepine receptors in lymphocytes of anxious patients: reversal after chronic diazepam treatment.

Peripheral-type benzodiazepine receptors were measured in human circulating lymphocytes using 3H-PK 11195 as specific ligand. In a group of outpatients with anxiety disorders a significant decrease of receptor density (-37%) was found compared with age-matched controls. In these patients long-term diazepam treatment restored binding density to normal levels: the effect persisted after drug withdrawal. Acute i.v. diazepam administration did not change receptor density. The observed receptor changes could reflect a down-regulation phenomenon and indicate that lymphocyte function reflect central nervous events.

Anxiety Disorders↗
PubMed1990

Decrease in phorbol ester receptors in human brain tumors.

We have characterized the specific binding of [3H]-phorbol-12,13-dibutyrate in the white and gray matter of normal human brain and in cerebral tumors as an index of the availability of protein kinase C enzyme molecules. White matter has less than 50% phorbol-ester-binding capacity in comparison to gray matter. The binding is lower in tumors of glial origin when compared with normal white matter. Tumors of nonglial origin such as neurinoma and meningioma have a lower binding capacity than glial tumors. Metastatic tissues have the lowest binding capacity. The analysis of binding parameters in tumors and in the corresponding normal peritumoral tissues confirms the decreased binding capacity of neoplastic tissues in comparison to tissues not undergoing malignant transformation. These data suggest that brain glial tumors have a low availability of protein kinase C enzyme molecules and point to the potential involvement of this system in malignant transformation of human brain cells.

Adult↗
PubMed1990

Cerebrospinal fluid levels of diazepam-binding inhibitor in neurodegenerative disorders with dementia.

We investigated CSF levels of diazepam-binding inhibitor (DBI), a recently discovered neuropeptide that allosterically modulates GABAergic transmission, in various neurodegenerative disorders with dementia (28 patients with Parkinson's disease, 10 with Alzheimer's disease, 7 with Huntington's chorea). We applied a battery of neuropsychological tests to determine the degree of dementia and to exclude the presence of mood alterations. CSF DBI levels were elevated in parkinsonian subjects with dementia and in patients with Alzheimer's disease, but decreased in Huntington's chorea patients. We hypothesize that modifications of CSF DBI levels may be related to a functional or structural alteration of the GABAergic system.

Adult↗
PubMed1989

Benzodiazepine receptors and diazepam-binding inhibitor in human cerebral tumors.

Benzodiazepines can regulate neoplastic growth and immune response through specific peripheral benzodiazepine receptors. We investigated the presence of peripheral and classic central benzodiazepine receptors as well as diazepam-binding inhibitor, an endogenous ligand of both types of receptors, in different human cerebral tumors. Peripheral benzodiazepine receptors were present in all the tumor types studied, whereas central benzodiazepine receptors and diazepam-binding inhibitor were detectable in astrocytomas and glioblastomas and undetectable in meningiomas, neurinomas, and metastases. The role of diazepam-binding inhibitor and of the different benzodiazepine receptors in neoplastic cells is still to be defined.

Adolescent↗
PubMed1989

Distribution of a putative endogenous modulator of the GABAergic system in human brain.

Diazepam binding inhibitor (DBI) is a novel neuropeptide purified from rat, cow, and human brain that allosterically modulates GABAergic transmission by binding to benzodiazepine (BDZ)-recognition sites. Using a specific radioimmunoassay for human DBI, we investigated the distribution of this peptide in different brain areas. We characterized with high-pressure liquid chromatography the DBI immunoreactivity in brain tissue obtained by biopsy and autopsy; we detected one molecular species of DBI in both instances. The regional distribution of DBI in the human brain is similar to that observed in rat brain: high concentrations in cortical and limbic areas, cerebellum, and brainstem, and low concentrations in the basal ganglia. These data suggest a modulatory role for DBI in human brain.

Brain↗
PubMed1987

Calmodulin content in human brain tumors.

Using a radioimmunoassay method, the particulate and soluble calmodulin levels were determined in biopsied specimens from normal human brain and from various human brain tumors. Both in normal and pathological tissues the major portion of calmodulin was revealed in the cytosol. The chromatographic elution profiles of calmodulin obtained from soluble and particulate fractions of the same specimen were identical, thus suggesting an identity of the supernatant and particulate form of calmodulin. In all the examined oncotypes, the calmodulin content was lower than in normal extracts and this biochemical feature could not have been correlated with the degree of malignancy of the neoplasia. Furthermore, the translocation of calmodulin from the particles to the cytoplasm, reported in other rapidly growing tumors, lacks in human cerebral ones. Our findings indicate that in human brain oncotypes the calmodulin distribution is quite different from that found in tumors taken from other tissues, where its level is increased and a positive correlation between calmodulin concentration and growth rate of neoplastic tissue has been revealed.

Adult↗