Biomedical subjects

I Appollonio

Publications and source records attributed to I Appollonio.

39 records · Page 3Linked to original sources

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↗

PubMedDate not supplied

Functional MRI: primary motor cortex localization in patients with brain tumors.

PURPOSE: Our goal was (a) to test the ability of functional MRI (fMRI) to localize the hand primary motor cortex in patients with brain neoplasms using a conventional scanner and (b) to compare within the same subject the location and morphology of the activated motor areas in the affected hemisphere with the contralateral ones. METHOD: Seventeen right-handed patients with frontoparietal intra- and extraaxial tumors were studied. Hand motor performance ranged from normal to slight impairment of finger dexterity. The fMRI study was based on a series of FLASH images. Two or three contiguous slices parallel to the bicommissural plane were acquired through the level of frontoparietal cortex. Each patient was requested to perform with each hand a finger-tapping task or a simpler repetitive flexion-extension of the last four fingers. Pseudo-color activation maps were then calculated by a Z-score method and superimposed on high resolution images. RESULTS: Five patients were excluded because of gross motion artifacts. In all other patients, areas of significant signal increase were detected on the precentral gyrus. They had a spot-like appearance, and no substantial side-to-side differences in shape or extension could be observed. In the presence of severe compression of the gyri, a displacement of the activated areas in the affected hemisphere with respect to the contralateral ones was noticeable. CONCLUSION: fMRI localization of the primary motor area using a conventional scanner can be obtained also in patients with brain tumors, although with a lower success rate than in normal volunteer studies, mainly because of subject compliance problems. Areas of significantly increased signal are detectable even in cortex where normal anatomical patterns are lost.

Adolescent↗