Objectives-To assess the frequency of hyperthermia in a population of acute neurosurgical patients; to assess the relation between brain temperature (ICT) and core temperature (Tc); to investigate the eVect of changes in brain temperature on intracranial pressure (ICP). Methods-The study involved 20 patients (10 severe head injury, eight subarachnoid haemorrhage, two neoplasms) with median Glasgow coma score (GCS) 6. ICP and ICT were monitored by an intraventricular catheter coupled with a thermistor. Internal Tc was measured in the pulmonary artery by a Swan-Ganz catheter. Conclusions-Fever is extremely frequent during acute cerebral damage and ICT is significantly higher than Tc. Moreover, Tc may underestimate ICT during the phases when temperature has the most impact on the intracranial system because of the close association between increases in ICT and ICP. (J Neurol Neurosurg Psychiatry 2001;71:448-454) Results-Mean

We used yeast "two-hybrid" screening to isolate cDNA-encoding proteins interacting with the N-terminal domain of the Ras nucleotide exchange factor CDC25 Mm . Three independent overlapping clones were isolated from a mouse embryo cDNA library. The fulllength cDNA was cloned by RACE-polymerase chain reaction. It encodes a large protein (1080 amino acids) highly homologous to the human deubiquitinating enzyme hUBPy and contains a well conserved domain typical of ubiquitin isopeptidases. Therefore we called this new protein mouse UBPy (mUBPy). Northern blot analysis revealed a 4-kilobase mRNA present in several mouse tissues and highly expressed in testis; a good level of expression was also found in brain, where CDC25 Mm is exclusively expressed. Using a glutathione S-transferase fusion protein, we demonstrated an "in vitro" interaction between mUBPy and the N-terminal half (amino acids 1-625) of CDC25Mm . In addition "in vivo" interaction was demonstrated after cotransfection in mammalian cells. We also showed that CDC25 Mm , expressed in HEK293 cells, is ubiquitinated and that the coexpression of mUBPy decreases its ubiquitination. In addition the half-life of CDC25Mm protein was considerably increased in the presence of mUBPy. The specific function of the human homolog hUBPy is not defined, although its expression was correlated with cell proliferation. Our results suggest that mUBPy may play a role in controlling degradation of CDC25 Mm , thus regulating the level of this Ras-guanine nucleotide exchange factor. Ras-guanine nucleotide exchange factors (GEFs)1 are proteins that stimulate the exchange of guanine nucleotides (GDP/ GTP) on Ras proteins. We have previously cloned a mouse brain-specific Ras-GEF, called CDC25Mm (1-2) or Ras-GRF1. CDC25Mm is a large protein (140 kDa) that contains a Rasexchange domain in the C-terminal region and several different domains in the large N-terminal region, namely two PH (pleckstrin homology) domains, one DH (Dbl homology) domain, and an illimaquinone (IQ) domain (2-3). In addition a coiled-coil region and a PEST sequence were identified (4).Several evidences indicate that the large N-terminal region of CDC25Mm has a regulatory function and may interact with other cellular components. We have previously shown that the expression in mouse fibroblasts of a truncated form of CDC25 Mm , lacking the Ras exchange domain, behaves as a dominant negative protein (5). In addition PH domains could interact with phospholipids (6) and with the ␤␥ subunits of heterotrimeric G proteins (7), whereas the IQ domain binds calmodulin (3,8) and is thought to be responsible for the activation of GEF activity by calcium (3). Further evidence that the N-terminal region of CDC25Mm protein is involved in specific protein interaction(s) also comes from the work of Kiyono et al. (9) in which it was shown that CDC25 Mm /Ras-GRF1 was able to activate Rac1 and that for this activity a functional DH domain is required. Moreover the DH domain was required for homodimerization of Ras-GRF1 or for heterodi...

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The aim of this research was to determine whether the structural homology between the O2 gene, a maize transcriptional activator, and the GCN4 gene, a yeast transcriptional factor, is reflected at the level of function. The O2 cDNA was cloned in the yeast expression vector pEMBLyex4 under the control of a hybrid inducible promoter, and used to transform the yeast Saccharomyces cerevisiae. Transformed yeast cells produced O2 mRNA and a polypeptide immunoreactive with anti-O2 antibodies during growth in galactose. The heterologous protein was correctly translocated into the yeast nuclei, as demonstrated by immunofluorescence, indicating that the nuclear targeting sequences of maize are recognized by yeast cells. Further experiments demonstrated the ability of O2 to rescue a gcn4 mutant grown in the presence of aminotriazole, an inhibitor of the HIS3 gene product, suggesting that O2 activates the HIS3 gene, gene normally under control of GCN4. It was shown that the O2 protein is able to trans-activate the HIS4 promoter in yeast cells and binds to it in vitro. The sequence protected by O2, TGACTC, is also the binding site for GCN4. Finally, the expression of O2 protein in yeast did not produce alterations during batch growth at 30 degrees C, while transformants expressing O2 protein showed a conditionally lethal phenotype when grown in galactose at 36 degrees C; this phenotype mimics the behaviour of gcd mutants. The results support the idea that basic mechanisms of transcription control have been highly conserved in eukaryotes.

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