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Biomedical subjects

G de Rossi

Publications and source records attributed to G de Rossi.

At least 19 recordsLinked to original sources
PubMed1996

SPET monitoring of perfusion changes in auditory cortex following mono- and multi-frequency stimuli.

AIM: In order to assess the relationship between auditory cortex perfusion and the frequency of acoustic stimuli, twenty normally-hearing subjects underwent cerebral SPET. METHODS: In 10 patients a multi-frequency stimulus (250-4000 Hz at 40 dB SL) was delivered, while 10 subjects were stimulated with a 500 Hz pure tone at 40 dB SL. The prestimulation SPET was subtracted from poststimulation study and auditory cortex activation was expressed as percent increments. RESULTS: Contralateral cortex was the most active area with multi-frequency and monofrequency stimuli as well. A clear demonstration of a tonotopic distribution of acoustic stimuli in the auditory cortex was achieved. In addition, the accessory role played by homolateral acoustic areas was confirmed. CONCLUSION: The results of the present research support the hypothesis that brain SPET may be useful to obtain semi-quantitative reliable information on low frequency auditory level in profoundly deaf patients. This may be achieved comparing the extension of the cortical areas activated by high-intensity multifrequency stimuli.

Acoustic Stimulation↗
PubMed1984

Heterogeneous expression of dipeptidyl-amino-peptidase (DAP IV) in T-cell chronic lymphocytic leukemia.

The reactivity for the enzyme dipeptidyl-amino-peptidase IV (DAP IV) has been correlated, in 8 cases of T-cell chronic lymphocytic leukemia (T-CLL), with the cellular phenotype as well as the morphological and clinical behaviour of disease. A highly reproducible correspondence between the 'helper' phenotype (OKT4+/Fc mu-R+) and DAP IV expression was observed in cases with aggressive disease, whereas the cases with OKT8+/Fc mu-R+ phenotype was characterized by a favorable prognosis, LGL (large granular lymphocyte) morphology, and were virtually negative for DAP IV.

Adult↗
PubMed1983

HNK-1 monoclonal antibody (Leu-7) in the identification of abnormal expansions of large granular lymphocytes.

Among 12 cases of chronic T lymphoproliferative disorders we observed, six patients showed an expansion of mononuclear cells with azurophilic granules usually referred to as large granular lymphocytes or LGL. Cells obtained from five patients with these abnormal LGL proliferations were studied with several surface markers including their reactivity with the HNK-1 monoclonal antibody reported to be specific for LGL. Cells in four out of five cases were HNK-1 positive. Whereas normal LGL have been reported to be unreactive with several T cell markers, three cases showed the co-existence of HNK-1 and surface markers expressed by T cells. Two cases were characterized by the proliferation of OKT8 cells. Cells from one patient were HNK-1 positive but did not express T or monocytic antigens. These cells were apparently not completely mature since alpha-naphthyl acetate acid esterase activity was negative. Cells from the remaining case were HNK-1 negative and positive for T and monocytic antigens. An increase of OKT-10 cells was observed in only one patient. Our data indicate that proliferations of LGL represent a remarkable proportion of the rare cases of sheep erythrocyte rosetting chronic lymphocytic leukaemias or lymphomas. Besides the morphology of LGL, the rosetting ability and the negativity for peroxidase, cells from these cases showed a vast heterogeneity of other structural and functional markers, possibly reflecting different stages in the maturation of these cells. The HNK-1 monoclonal antibody proved to be an important marker in the identification of these cases.

Adult↗