Molecular cloning of mouse glycolate oxidase. High evolutionary conservation and presence of an iron-responsive element-like sequence in the mRNA

Iron regulatory proteins (IRPs) control the synthesis of several proteins in iron metabolism by binding to iron-responsive elements (IREs), a hairpin structure in the untranslated region (UTR) of corresponding mRNAs. Binding of IRPs to IREs in the 5' UTR inhibits translation of ferritin heavy and light chain, erythroid aminolevulinic acid synthase, mitochondrial aconitase, and Drosophila succinate dehydrogenase b, whereas IRP binding to IREs in the 3' UTR of transferrin receptor mRNA prolongs mRNA half-life. To identify new targets of IRPs, we devised a method to enrich IRE-containing mRNAs by using recombinant IRP-1 as an affinity matrix. A cDNA library established from enriched mRNA was screened by an RNA-protein band shift assay. This revealed a novel IRE-like sequence in the 3' UTR of a liver-specific mouse mRNA. The newly identified cDNA codes for a protein with high homology to plant glycolate oxidase (GOX). Recombinant protein expressed in bacteria displayed enzymatic GOX activity. Therefore, this cDNA represents the first vertebrate GOX homologue. The IRE-like sequence in mouse GOX exhibited strong binding to IRPs at room temperature. However, it differs from functional IREs by a mismatch in the middle of its upper stem and did not confer iron-dependent regulation in cells.     

The venotonic drug hydroxyethylrutosiden does not prevent or reduce docetaxel-induced fluid retention: results of a comparative study

PURPOSE: Fluid retention, which includes peripheral edema, ascites, pleural or pericardial effusion, or a combination of these that is sometimes associated with significant weight gain, is one of the most troublesome cumulative side effects of docetaxel. A suggestive observation from the data base available at the manufacturer (Rhone-Poulenc Rorer) was that patients who received venotonic drugs appeared to tolerate more courses of docetaxel. This prompted a comparative study to investigate whether the venotonic drug hydroxyethylrutosiden could reduce or delay docetaxel-related fluid retention. METHODS: A total of 85 patients with metastatic breast cancer who were treated with docetaxel at a dose of 100 mg/m2 with corticoid comedication were allocated to receive either 300 mg hydroxyethylrutosiden given orally four times daily (group A) or no hydroxyethylrutosiden (group B). The end point for analysis was the development of fluid retention of > or = grade 2. RESULTS: Fluid retention of > or = grade 2 was reported in 14 of 42 patients (33%) in group A and in 15 of 43 patients (35%) in group B and occurred after a median of 4 cycles of docetaxel in both groups. Weight gain was similar in groups A and B. CONCLUSION: We conclude that hydroxyethylrutosiden does not reduce or delay the incidence and severity of docetaxel-related fluid retention.     

Interaction of kunjin virus with octyl-D-glucoside extracted Vero cell plasma membrane

Initial experiments using whole cells have shown that there were specific and saturable interactions between kunjin (KUN) virus and receptor molecules on the Vero cell surfaces. Solubilisation of Vero cell plasma membranes with octyl-D-glucoside (OG) yielded an extract which also interacted specifically with KUN virus. This was proven using electron microscopy. When the virus-OG-extract complex was exposed onto Vero cell monolayers, no KUN virus was observed to enter into the whole cells. This would imply that there was virus-receptor interaction with the OG-extract leaving no free virus to attach to the whole cells. The attachment kinetics of KUN virus was studied further using the Scatchard analysis which indicated the involvement of more than one interactive macromolecule in the attachment event.     

Involvement of sphingosine 1-phosphate in nerve growth factor-mediated neuronal survival and differentiation

Sphingolipid metabolites, such as ceramide and sphingosine-1-phosphate (SPP), are emerging as a new class of second messengers involved in cellular proliferation, differentiation, and apoptosis. Nerve growth factor (NGF), a neurotrophic factor for pheochromocytoma PC12 cells, induced a biphasic increase in the activity of sphingosine kinase, the enzyme that catalyzes the formation of SPP. This activation was blocked by K252a, an inhibitor of tyrosine kinase A (trkA). A rapid 1.7-fold increase was followed by a marked prolonged increase reaching a maximum of fourfold to fivefold stimulation with a concomitant increase in SPP levels and a corresponding decrease in endogenous sphingosine levels. Levels of ceramide, the precursor of sphingosine, were only slightly decreased by NGF in serum-containing medium. However, NGF decreased the elevation of ceramide induced by serum withdrawal. Treatment of PC12 cells with SPP did not induce neurite outgrowth or neurofilament expression, yet it enhanced neurofilament expression elicited by suboptimal doses of NGF. Moreover, SPP also protected PC12 cells from apoptosis induced by serum withdrawal. To further substantiate a role for SPP in the cytoprotective actions of NGF, we found that N, N-dimethylsphingosine, a competitive inhibitor of sphingosine kinase, also induced apoptosis and interfered with the survival effect of NGF. These effects were counteracted by exogenous SPP. Moreover, other structurally related compounds, such as dihydrosphingosine 1-phosphate and lysophosphatidic acid, had no significant protective effects. Our results suggest that activation of sphingosine kinase and subsequent formation of SPP may play an important role in the differentiation and survival effects induced by NGF.     

Bax- and Bak-induced cell death in the fission yeast Schizosaccharomyces pombe

The dental profession faces educational, scientific, and ethical challenges in orofacial pain and headache. Past educational deficiencies are being addressed with guidance and recommendations from the AADS, the ADA, and the AAOP. With education and further research, many dental ethical questions in TMD will be resolved. The educational process must continue with a solid foundation in scientific basis provided in university settings. The appropriate use of TMD diagnostic machines, treatment modalities, and management of perpetuating factors such as sleep will evolve with the new knowledge of scientific discovery. These are some of the many challenges of orofacial pain and headache disorders that warrant special consideration.     

Prognostic significance of tumour markers in endometrial cancer

BACKGROUND: Steroid 5 alpha-reductase is implicated in the pathogenesis of benign prostatic hyperplasia (BPH). We studied the in vitro and in vivo effects of FR146687, a new inhibitor of 5 alpha-reductase. METHODS: Two isozymes of rat and human 5 alpha-reductases were expressed in 293 cells. In vivo effects of drugs were evaluated on rat and dog prostates. Castrated immature rats were injected with testosterone propionate (TP) or 5 alpha-dihydrotestosterone propionate (DHTP) to induce growth of the ventral prostates. Testosterone and 5 alpha-dihydrotestosterone (DHT) contents in rat and dog prostates were measured by gas chromatography-mass spectrophotometry (GC-MS). RESULTS: FR146687 showed noncompetitive inhibition in both isozymes and no inhibitory effects on other steroid oxidoreductases. In mature rats and castrated immature rats treated with TP, FR146687 dose-dependently reduced ventral prostate and seminal vesicle weight at doses above 0.1 mg/kg, while castrated immature rats treated with DHTP were not affected by FR146687. FR146687 showed more potent reduction of rat prostates than finasteride. DHT concentration in the prostates was significantly reduced when FR146687 was administered to rats and beagles. CONCLUSIONS: FR146687 is a dual inhibitor for 5 alpha-reductase isozymes and significantly reduced the growth and DHT content in the prostate.