key: cord-0033583-9pt58e1y authors: nan title: Biomedical vignette date: 2004-01-03 journal: J Biomed Sci DOI: 10.1007/bf02256542 sha: 80485e40787d8d40a88b005c57beecbcad47f601 doc_id: 33583 cord_uid: 9pt58e1y nan Sympathetic stimulation, similar to norepinephrine, induces cardiac hypertrophy [ 14] . Of the diverse stimuli that lead to cardiac hypertrophy, a prototypical final molecular response of cardiomyocytes to hypertrophic signals involves an increase in protein synthesis and expression of the [3myosin heavy chain ([3-MyHC) gene [23] . Liu et al. [13] studied the intracellular mechanism that underlies the cardiac protective effect of tritinolein, using primary culture of rat ventricular myocytes. Their results indicate that trilinolein inhibits norepinephrine-induced protein synthesis, [3-MyHC gene promoter activity and intraeeIlular oxygen radicals, and suggest that inhibition of norepinephrine-induced protein synthesis by trilionlein may be mediated through the attenuation of oxygen radical generation. Intravascular thrombosis is one of the generators of a wide variety of cardiovascular diseases. At the same time, magnesium sulfate has been shown to reduce platelet aggregation both in vitro and ex vivo [8, 20] . Hsiao et al. [6] showed that magnesium sulfate inhibits aggregation of human platelets in a concentration-dependent manner, along with reduced phosphoinositide breakdown, intracellular Ca 2+ mobiIization, protein kinase C activation or thrombin-evoked increase in pHi. They conclude that these changes may be associated with the antiplatelet activity of magnesimn sulfate. The risk of cardiovascular diseases in postmenopausal women on hormone replacement therapy is halved [1], possibly because of the protection provided by estrogens to the cardiovascular system. One possible underlying mechanism is that estrogens inhibit the proliferation and migration of vascular smooth muscle cells, partly by suppressing endothelin-1 gene expression induced by angiotensin II [28] . Hong et al. [5] propose a signal transduction cascade between angiotensin II treatment and cell proliferation that includes sequentially reactive oxygen species, ERK kinase, AP-1 and endothelin-1. This signaling mechanism provides an explanation for estradiol inhibition of vascular smooth muscle cell proliferation via downregulation of angiotensin II-induced endothelin-1 gene expression. Retinitis pigmentosa is characterized by progressive degeneration of the photoreceptors, leading to a combination of constricted visual field, night blindness and loss of central vision [25] . Huang et al. [7] investigated the effects of ciliary neurotrophic factor (CNTF), a powerful inducer of nerve fiber formation in retinal development [10] , using Royal College of Surgeons rats, which exhibit recessive hereditary retinal dystrophy. They observed that both recombinant CNTF and adenovirus CNTF gene transfer exert a potent delaying effect on the process of photoreceptor degeneration, although the latter is more efficacious. These results suggest that adenoviral CNTF may be beneficial in diseases such as retinitis pigmentosa. The large number of neutrophils consequent on exposure to potent neutrophil mediators, including neutrophiI elastase, places the airspace in great jeopardy [24] . In addition, neutrophil-derived elastase, protein 3 or defensins induce IL-8 in lung epithelial cells [26] . Chen et al. [2] used cultured A549 epithelial cells to study the signal transduction pathway of neutrophit elastase-induced IL-8 expression. They report that neutrophiI elastase activates p38 MAPK to upregulate NF-KB and AP-I activities, leading to the induction of IL-8 expression. Furthermore, tyrosine kinase and protein kinase C are implicated in neu-trophiI elastase activation of the MAPK pathway. Myeloperoxidase (MPO) is an oxidative enzyme that is able to form proatheroscterotic particles by its oxidative intermediates. An elevated MPO Ievel in the blood is associated with coronary artery disease (CAD), and persons with MPO deficiency have a reduced risk of cardiovascular damage [30] . A sequence polymorphism affects the Sp 1 binding site of the MPO transcriptional promoter, and leads to high (GIG genotype) and low expressers (A/A and A/G). The low expression genotype was recently correlated with protection against CAD [16] . The study by M~ikel~i et al, [i5] presents evidence for the involvement of the MPO genotype in early steps of CAD development, as measured by endothelial changes that affect the coronary flow reserve, Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract [17] . Current criteria for the diagnosis of malignant GISTs do not always reliably predict patient outcomes. Except for a small rectal tumor, Chen et al. [3] identified the presence of chromosomal imbalance aberrations (CIAs) in all 28 patients with GIST they examined. Among these CIAs, losses of 13q, i0q (with minimal overlapping on qI1-q22) and 22q are most likely the chromosomal loci potentially harboring the tumor suppressor gene(s) which may be related to early recurrence and/or metastasis during malignant transformation of GISTs. Chronic infection with hepatitis C virus (HCV) is often associated with the development of severe liver diseases, including cirrhosis and hepatocellular carcinoma [22] . Kao et aI. [9] investigated the implication that HCV core protein may be involved in the transregulation of RNA polymerase (Pol) I-dependent genes [27] . They report that the core protein is the only viral product that has the potential to activate RNA Pol I transcription. In particular, the fragment containing the N-terminal 1-156 residues and the integrity of the Ser ~x6 and Arg ~7 residues of HCV core protein are critical for this transregulatory function. The proposed mechanisms that underlie the actions of the HCV core protein include recruitment of the upstream binding factor (UBF) and RNA Pol I to the rRNA promoter, hyperphosphorylation of UBF on serine residues, association with the selecIivity zon81 o~ Biornedical Science factor via direct contact with TATA binding protein, and additional activation of RNA Pol II-and Pol III-mediated transcription. These results provide new insights into the role of HCV core in promoting cell growth and proliferation, and tile progression of liver carcinogenesis. Triton WR-1339, a cross-linked form of Triton X-100, has been shown to suppress the dissemination and metastasis of certain tumors [21 ] . Contrary to these results, others have reported that WR-t339 actually increases the chance that certain tumor cells will metastasize [19] . Picache et al. [18] report that Triton X-100 blocks cell proliferation through inhibition of cyclindependent Mnase. This finding is of interest since it provides a molecular insight into the effect of Triton X-100 on tumor cell growth. How hematopoietic stem cells choose between fates of proliferation and differentiation is not welt understood. Using a complexity reduction approach, Liu et al. [12] identified a gene called negative differentiation regulator (NDR), which is highly expressed in the human erythroleukemia K562 cell line and in CD34+ umbilical cord blood cells. They found that NDR is downregulated in response to 12-O-tetradecanoylphorbol-13-acetate (TPA) and that overexpression of NDR partially blocks TPA-induced megakaryocytic differentiation in a protein kinase C-dependent man-net. NDR therefore appears to be a novel regulator of hematopoietic ceil differentiation. Severe acute respiratory syndrome (SARS), a newly emerged viral infectious disease, has recently raised a worldwide alert [4] . Analysis of the profile of IgM and IgG antibody responses to SARS-coronavirus (CoV) [11] indicated that all patients tested negative 1 week after the onset of symptoms. In order to identify specific antibodies to different viral proteins in SARS patients, Wu et al. [29] purified different recombinant viral proteins in Escherichia coli and detected various immunoglobulin classes in serum samples from SARS patients. Of note is that N protein of SARS-CoV was recognized in most of the sera, and IgA antibodies against SARS-CoV could be detected within 1 week after the onset of ilhress in a few SARS patients. Combining Western blot with RT-PCR greatly enhances the confirmation of SARS-CoV infection. These results provide clues to the development of a rapid and accurate laboratory test for SARS viral infection. Hormonal treatment of postmenopausal women t3-Estradiol down regulates angiotensin-H-induced endothelin-1 gene expression in rat aortic smooth muscle ceils Involvement of the antiplatelet activity of magnesium sulfate in suppression of protein kinase C and the Na÷tH + exchanger Intraocular gene transfer of ciliary neurotrophic factor rescues photoreceptor degeneration in RCS rats Effect of intracellular magnesium on platelet activation and intraeellular calcium mobilization Activation of RNA polymerase I transcription by hepatitis C virus core protein Evidence for multiple, local functions of ciliary neurotrophic factor (CNTF) in retinal development: Expression of CNTF and its receptors and in vitro effects on target cells Profile of specific antibodies to the SARS-associated coronavirus Down-regulation of human NDR gene in megakaryocytic differentiation of erythroleukemia K562 cells The inhibitory effect of trilinolein on norepinephfineinduced 13-myosin heavy chain promoter activity, reactive oxygen species generation, and extracellular signal-regulated kinase phosphorylation in neonatal rat cardiomyocytes Simvastatin inhibits noradrenaline-induced hypertrophy of cultured neonatal rat cardiomyocytes Myeloperoxidase gene variation and coronary flow reserve in young healthy men A functional myeloperoxidase polymorphic variant is associated with coronary artery disease in French-Canadians Clinicopathotogical features of gastric stromal tumors Inhibition of tumor cell gro~h by Triton X-100 through specific effects on celI-cycle-regulatory components InIluence of ICRE 159 and triton WR 1339 on metastases of a rat epithelioma Magnesium inhibits platelet activity -an infusion study in healthy volunteers Effect of Triton WR 1339 on cancer dissemination and metastases HHepatitis C virus infection is associated with the development of hepatocellular carcinoma Various hypertrophic stimuli induce distinct phenotypes in cardiomyocytes Macrophages and polymorphonuclear neutrophils in lung defense and injury Rhodopsin and retinitis pigmentosa: Shedding light on structure and function Effect of neutrophil serine proteinase and defensins on lung epithelial cells: Modulation of cytotoxicity and IL-8 production Regulation of RNA polymerase I-dependent promoters by the hepatitis B virus X protein via activated Ras and TATA-binding protein Collins R 17beta-estradiol decreases endothelin-1 levels in the coronary circulation of postmenopausal women with coronary artery disease Early detection of antibodies against various structural proteins of the SARS-associated coronavirus in SARS patients Association between myeloperoxidase levels and risk of coronary artery disease