Assuntos
Parto Obstétrico , Sangue Fetal/química , Trabalho de Parto Prematuro/sangue , Proteínas S100/sangue , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Masculino , Fatores de Crescimento Neural , Gravidez , Terceiro Trimestre da Gravidez , Subunidade beta da Proteína Ligante de Cálcio S100RESUMO
The aim of this study was to assess the use of S100 protein in blood as a means of identifying preterm infants at risk of intraventricular hemorrhage. In 25 preterm newborns, S100 blood concentrations were measured by an immunoradiometric assay during the first 48 h. Cerebral Doppler velocimetry waveform patterns were also tested at the time the blood sample was taken, when clinical and cerebral ultrasound scanning were still normal. Of the 25 newborns studied, 14 were controls and 11 developed intraventricular hemorrhage as revealed by ultrasound scanning more than 72 h after birth, and clinically confirmed by neurological examination on the seventh day of follow-up. S100 blood concentrations were significantly higher (P<0.002) in infants with intraventricular hemorrhage than in control infants and also correlated significantly (r=0.81, P<0.003) with the grade of hemorrhage. A significant correlation (r=0.70, P<0.05) between the S100 blood concentration and the middle cerebral artery pulsatility index was also observed. The present data show that S100 blood concentrations offer a measurable parameter of brain lesion in preterm infants before a radiological assessment of hemorrhage can be performed, when clinical symptoms may be silent and preventive/therapeutic action could be especially useful.
Assuntos
Hemorragia Cerebral/sangue , Hemorragia Cerebral/diagnóstico por imagem , Circulação Cerebrovascular , Recém-Nascido Prematuro , Proteínas S100/sangue , Velocidade do Fluxo Sanguíneo , Artérias Cerebrais/fisiopatologia , Hemorragia Cerebral/mortalidade , Hemorragia Cerebral/fisiopatologia , Humanos , Recém-Nascido , Exame Neurológico , Concentração Osmolar , Fluxo Pulsátil , UltrassonografiaRESUMO
The present study investigates, by immunocytochemistry, the behavior of different neuronal subpopulations of the developing rat hippocampus, selectively labeled by the calcium-binding proteins calbindin D28-k (CB), parvalbumin (PV), and calretinin (CR), in neurodegenerative processes induced by the neurotoxicant trimethyltin (TMT). Previous studies on adult rats indicated that CB-immunoreactive (IR) neurons were affected by TMT, while PV- and CR-IR neurons were selectively spared. The present findings show that only CR-IR neurons are spared in developing rats, and in addition the number of CR-IR neurons are significantly higher in the DG of treated animals. On the contrary, PV-IR neurons, spared in adult rats, were affected by TMT during development. CB-IR neurons were affected also in developing rats, as in adults. The different postnatal time-courses of calcium-binding protein expression in relationship to the time of TMT administration (presence of CR but absence of PV) could have a role in the different behavior of CR- and PV-IR cells in developing rats.
Assuntos
Hipocampo/citologia , Degeneração Neural/metabolismo , Neurônios/citologia , Parvalbuminas/análise , Proteína G de Ligação ao Cálcio S100/análise , Animais , Animais Recém-Nascidos , Química Encefálica/fisiologia , Calbindina 2 , Calbindinas , Hipocampo/crescimento & desenvolvimento , Degeneração Neural/induzido quimicamente , Proteínas do Tecido Nervoso/análise , Neurônios/química , Neurônios/metabolismo , Ratos , Compostos de TrimetilestanhoRESUMO
The present study uses immunocytochemistry to investigate the behavior of the calretinin (CR)-containing neuronal subpopulation (interneurons) of the rat hippocampus in neurodegenerative processes induced by the neurotoxicant trimethyltin. Cell counts of CR-immunolabeled interneurons indicated that these cells are spared by the neurotoxicant-induced degeneration, characterized by a generalized neuronal loss, as shown by quantitative analysis after cresyl violet staining.
Assuntos
Hipocampo/efeitos dos fármacos , Interneurônios/efeitos dos fármacos , Degeneração Neural/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurotoxinas/toxicidade , Proteína G de Ligação ao Cálcio S100/análise , Compostos de Trimetilestanho/toxicidade , Animais , Benzoxazinas , Calbindina 2 , Corantes , Feminino , Hipocampo/citologia , Hipocampo/patologia , Imuno-Histoquímica , Interneurônios/citologia , Interneurônios/patologia , Proteínas do Tecido Nervoso/análise , Neurônios/citologia , Neurônios/patologia , Oxazinas , Ratos , Ratos WistarRESUMO
After acute trimethyltin (TMT) intoxication (21 d after a single i.p. injection at a dose of 8 mg/kg) the histological, immunohistochemical, and immunochemical investigation of adult rat hippocampus showed a distinct pattern of neuronal loss, and an increase in both glial fibrillary acidic protein- (GFAP) immunoreactive cells and GFAP concentration, as expected. S-100-immunoreactive cells also increased markedly, whereas the concentration of S-100 increased even more than that of GFAP. The data show that S-100 is an index of glial reaction to damage after TMT intoxication and suggest the potential usefulness of exploring the possibility that it may play a role in induced neurodegenerative processes.
Assuntos
Hipocampo/metabolismo , Degeneração Neural/metabolismo , Degeneração Neural/prevenção & controle , Proteínas S100/metabolismo , Compostos de Trimetilestanho/toxicidade , Animais , Western Blotting , Ensaio de Imunoadsorção Enzimática , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Hipocampo/efeitos dos fármacos , Imuno-Histoquímica , Neuroglia/efeitos dos fármacos , Neuroglia/fisiologia , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Ratos , Ratos WistarRESUMO
The present study investigates, by immunocytochemistry, the behavior of different neuronal subpopulations of the rat hippocampus in neurodegenerative processes induced by the neurotoxicant trimethyltin. The calcium-binding proteins calbindin and parvalbumin are used as selective markers of different neuronal subpopulations. The effects of the neurotoxicant were apparent 21 days after a single i.p. administration with severe neuronal loss, which was significant in CAI and CA3, as revealed by cell counts after cresyl violet staining. Immunolabeling with calbindin D28-k (CB) and parvalbumin (PV) indicated severe cell loss of CB-containing neurons, essentially reflecting the generalized neuronal loss, while PV-containing neurons appeared to be selectively spared by the neurotoxicant-induced degeneration.
Assuntos
Hipocampo/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Parvalbuminas/análise , Compostos de Trimetilestanho/farmacologia , Animais , Feminino , Hipocampo/ultraestrutura , Imuno-Histoquímica , Degeneração Neural/efeitos dos fármacos , Neurônios/imunologia , Ratos , Ratos WistarRESUMO
The brown adipose tissue (BAT) is responsible for nonshivering thermogenesis, exhibiting changes in cell morphology related to the functional conditions. In stimulated BAT (neonatal period, cold acclimation) the large majority of adipocytes become multilocular and active, while in inactive BAT (warm acclimation) most cells are pauci- or unilocular and inactive, very similar to white adipocytes. It is well known that white adipocytes are sites of concentration of S-100, a calcium-binding protein originally isolated from the nervous system and later detected also in nonneural cell types, whereas data on the possible presence of this protein in BAT are lacking. The present study used morphological, immunocytochemical, and immunochemical methods to investigate the presence of S-100 protein in BAT under different functional conditions. We found that S-100 was present in both stimulated and inactive BAT and that is was expressed in significantly higher quantities in the latter than in the former. The multilocular cells were always negative (in both active and inactive tissue), whereas the pauci- and unilocular cells were always S-100-positive under both functional conditions. These data suggest that only pauci- and unilocular brown adipocytes express S-100 protein, thus manifesting a possible relationship between S-100 and cell morphology.