Expression of myosin heavy chain isoforms in the human supraspinatus muscle: variations related to age and sex.

The contractile function of skeletal muscles is primarily regulated by the expression of myosin heavy chain (MHC) isoforms. Adult human skeletal muscles express three MHC isoforms (MHC-I, MHC-IIa and MHC-IIx). The muscles mainly expressing MHC-I are slow but resistant to fatigue, while those with major expression of MHC-IIa and MHC-IIx are fast and powerful but less resistant to fatigue. In this study, mRNA levels of the MHC isoforms were assessed in 24 human supraspinatus muscles by reverse-transcription polymerase chain reaction. The average expression of the MHC-I isoform was 36.72%, that of the MHC-IIa isoform was 33.52%, and the average expression of the MHC-IIx isoform was 29.76%. The higher average expression of the two MHC-II isoforms taken together (63.28%) indicates that the human supraspinatus muscle is a powerful, fast muscle with relatively low resistance to fatigue, in accordance with its role in the elevation of the upper extremity. In women, and more markedly in older women, the trend towards upregulation of the fast MHC-II isoforms and downregulation of the slow MHC-I isoform, which is absent in males, may improve our understanding of possible causes of the subacromial impingement syndrome.

Regulation of α2-adrenoceptor gene expression by chronic lithium treatment in rat brain.

One of the approaches for the treatment of bipolar disorder involves the coadministration of lithium, a mood stabilizer, with α2-adrenoceptor antagonists possessing an antidepressant effect. Since lithium accelerates the recovery of α2(D)-adrenoceptors following their irreversible inactivation with N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ), our aim was to examine if it could be to some changes in Adra2A gene expression which codifies these adrenoceptors. Animals were treated with lithium chloride (120 mg/kg i.p.) or saline once a day for 10 days. A group of lithium- or saline-treated rats was killed 48 h after the last injection. The remaining animals were treated with EEDQ and were killed at 0.25, 4 and 14 days following this administration. Total RNA was extracted from cerebral cortex and Adra2A gene expression was measured by RT-QPCR. The results show that chronic lithium raised the Adra2A gene expression (P < 0.05), and after EEDQ administration this expression decreased to the basal level. No change in Adra2A gene expression was detected in the saline-treated group. However, EEDQ administration produced an insignificant increase in α2-adrenoceptors mRNA levels followed by a progressive decrease until basal levels. Lithium produced an overexpression of the Adra2A gene after chronic treatment that made the neuron ready to produce α2-adrenoceptors to deal with their inactivation.

Tumour CD133 mRNA expression and clinical outcome in surgically resected colorectal cancer patients.

BACKGROUND: Human prominin-1 (CD133) is a novel pentaspan membrane protein which was originally classified as a marker of primitive haematopoietic and neural stem cells. Cancer stem cells have been isolated and expanded from leukaemia and several solid tumours, and have been associated with metastasis, chemoresistance and relapse. CD133 is recognised as a stem cell marker and is capable of identifying a tumour-initiating subpopulation in brain, colon, melanoma and other solid tumours. METHODS: We assessed CD133 mRNA expression levels by RT-QPCR in tumour and matched normal tissue from 64 stages I-III colorectal cancer (CRC) patients and correlated tumour CD133 levels with clinicopathological characteristics and clinical outcome. RESULTS: In four patients, CD133 mRNA was not expressed in tumour or in normal tissue. In the remaining 60 patients, expression levels were higher in tumour than in normal tissue (p=0.001). Higher levels of CD133 expression were associated with shorter relapse-free interval (RFI) (p=0.004) and overall survival (OS) (p<0.0001). In the multivariate analyses, CD133 levels emerged as a prognostic marker for RFI and OS. CONCLUSIONS: We have observed longer RFI and OS in patients with lower levels of CD133, regardless of adjuvant treatment and other clinical characteristics. If these findings are confirmed in larger prospective studies, CD133 assessment may prove useful for new diagnostic and therapeutic procedures for CRC patients.

Pharmacogenomics: a tool for improving cancer chemotherapy

When an anticancer drug is captured and transported to the interior of a cell, many biochemical processes intervene in the metabolism of the drug. First, the Phase I and Phase II enzymes produce metabolites, which are then excreted via the ABC-transporter enzymes. Finally, the remaining drug binds to its molecular target. Genetic alterations known as polymorphisms in any of the proteins that intervene in these processes can affect the efficacy of treatment. Interestingly, these polymorphisms can be detected in both normal and tumour cells. In this article, we will review the most effective method of detecting single-nucleotide polymorphisms (SNPs) and describe the principal SNPs in enzymes involved in drug metabolism and in DNA repair. Finally, we will briefly describe promising lines of future research in this field (AU)

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