Expression of genes involved in the regulation of p16 in psoriatic involved skin

It has been suggested that the up-regulation of the tumour suppressor p16 gene and induction of senescence protect the phenotype of psoriatic involved skin from malignant transformation. On the other hand, Id1, which is inversely correlated with p16 has been shown to be up-regulated in psoriatic involved skin. To test the hypothesis that there may be an altered regulation of p16 in psoriatic involved skin, we have measured genes involved in the Igf-1 receptor signalling through the Ras/MAPK cascade. Igf-1R, IGFBP3, hRas, Ets2, JunB, Egr-1, Id1, MIDA1 and p16 gene expressions were measured using quantitative real-time PCR in total RNA isolated from punch biopsies from psoriatic involved (n=9) and uninvolved skin (n=9) and from cutaneous squamous cell cancer (SCC) involved (n=8) and uninvolved skin (n=8). The IGFBP3, hRas, JunB, Egr-1, Id1 and MIDA1 genes were up-regulated in psoriatic involved skin compared with uninvolved skin. The p16, JunB and MIDA1 genes were up-regulated in SCC involved skin compared with uninvolved skin. Our results indicate that there may be a balance between the proliferation and induction of senescence in psoriasis. This balance may vary and the psoriatic involved skin represented in this study appears to be in a proliferative state rather than senescence. Furthermore, we suggest that the noted up-regulation of JunB, which has been shown to up-regulate p16, in combination with the previously reported elevation of p16 expression in psoriatic involved skin, may indicate activation of a pathway by which JunB may protect the psoriatic plaque by inducing p16 in an event of malignant stress.     

Determinants of mortality in non-neutropenic ICU patients with candidaemia

Introduction  

Candidaemia in critically-ill intensive care unit (ICU) patients is associated with high crude mortality. Determinants of mortality – particularly those amenable to potential modification – are incompletely defined.     

Opioid Action on Respiratory Neuron Activity of the Isolated Respiratory Network in Newborn Rats

Background: Underlying mechanisms behind opioid-induced respiratory depression are not fully understood. The authors investigated changes in burst rate, intraburst firing frequency, membrane properties, as well as presynaptic and postsynaptic events of respiratory neurons in the isolated brainstem after administration of opioid receptor agonists.

Methods: Newborn rat brainstem-spinal cord preparations were used and superfused with [mu]-, [kappa]-, and [delta]-opioid receptor agonists. Whole cell recordings were performed from three major classes of respiratory neurons (inspiratory, preinspiratory, and expiratory).

Results: Mu- and [kappa]-opioid receptor agonists reduced the spontaneous burst activity of inspiratory neurons and the C4 nerve activity. Forty-two percent of the inspiratory neurons were hyperpolarized and decreased in membrane resistance during opioid-induced respiratory depression. Furthermore, under synaptic block by tetrodotoxin perfusion, similar changes of inspiratory neuronal membrane properties occurred after application of [mu]- and [kappa]-opioid receptor agonists. In contrast, resting membrane potential and membrane resistance of preinspiratory and majority of expiratory neurons were unchanged by opioid receptor agonists, even during tetrodotoxin perfusion. Simultaneous recordings of inspiratory and preinspiratory neuronal activities confirmed the selective inhibition of inspiratory neurons caused by [mu]- and [kappa]-opioid receptor agonists. Application of opioids reduced the slope of rising of excitatory postsynaptic potentials evoked by contralateral medulla stimulation, resulting in a prolongation of the latency of successive first action potential responses.     

Alterations in the regulatory pathway involving p16, pRb and cdk4 in human chondrosarcoma.

The G1 regulatory pathway involving p16, pRb and cdk4 in the cell cycle has been investigated in human chondrosarcoma. The protein expression of p16, pRb and cdk4 was analyzed by Western blot in cultured cells from eight chondrosarcomas and in two chondrosarcoma cell lines. Both cell lines and one other sample were negative for p16. Moreover, one of the cell lines was pRb-negative and showed a high expression of cdk4 as well. In the other cell line and in three other samples pRb of expected size were detected in addition to a shorter form of the protein. To further investigate the reasons for down-regulation of the p16 protein, the p16-coding gene CDKN2 was analyzed by polymerase chain reaction (PCR), methyl-specific PCR (MSP) and sequencing in all tumor samples as well as in corresponding tumor tissues from three of the samples. The p16-negative samples were all found to have homozygous deletion of CDKN2. Another sample showed partial gene methylation and a heterozygous position in codon 148 was detected in one sample. The same base substitution was also found in two of the tissue samples. Finally, cytogenetic analysis of the samples with homozygously deleted CDKN2 revealed multiple structural abnormalities in all three cases. In conclusion, the p16/pRb/cdk4 pathway may play an important role in the pathogenesis of some chondrosarcomas.