Human papillomavirus (HPV) type distribution in Korean women: a meta-analysis

The aim of the present study is to estimate the overall prevalence and type distribution of human papillomavirus (HPV) in Korean women, through literature review and meta-analysis. We searched published data for the period between 1995 and 2007 using the following inclusion criteria; (1) studies using type-specific HPV tests, (2) data from Korean female, (3) with cytologic or pathologic results, (4) having more than 20 cases for each subgroup classified by cytologic results, and (5) HPV detection including types 16, 18, and at least one other type. In total, 18 studies (13,842 cases) published up to April 2007 were identified and selected. Adjusted overall HPV prevalence was 23.9% (95% CI: 23.8-24.1%) in women with normal cytology and 95.8% (95% CI: 95.4-96.2%) in women with cervical cancer. Type 16 was predominant regardless of cervical disease status, and type 58 occupied a significantly larger proportion in high-grade cervical intraepithelial lesions and cervical cancer in Korean women. HPV types 58, 33, and 52 together accounted for about 20% of infections in cervical cancer and high-grade intraepithelial lesions. After introduction of HPV prophylactic vaccines, extended protection, especially against types 58, 33, and 52, will be an important issue for cervical cancer prevention in Korea. The future dominant genotypes will require follow-up epidemiological studies with a large-scale, multicentered, and prospective design.     

Theoretical analysis of the magnetocardiographic pattern for reentry wave propagation in a three-dimensional human heart model

We present a computational study of reentry wave propagation using electrophysiological models of human cardiac cells and the associated magnetic field map of a human heart. We examined the details of magnetic field variation and related physiological parameters for reentry waves in two-dimensional (2-D) human atrial tissue and a three-dimensional (3-D) human ventricle model. A 3-D mesh system representing the human ventricle was reconstructed from the surface geometry of a human heart. We used existing human cardiac cell models to simulate action potential (AP) propagation in atrial tissue and 3-D ventricular geometry, and a finite element method and the Galerkin approximation to discretize the 3-D domain spatially. The reentry wave was generated using an S1-S2 protocol. The calculations of the magnetic field pattern assumed a horizontally layered conductor for reentry wave propagation in the 3-D ventricle. We also compared the AP and magnetocardiograph (MCG) magnitudes during reentry wave propagation to those during normal wave propagation. The temporal changes in the reentry wave motion and magnetic field map patterns were also analyzed using two well-known MCG parameters: the current dipole direction and strength. The current vector in a reentry wave forms a rotating spiral. We delineated the magnetic field using the changes in the vector angle during a reentry wave, demonstrating that the MCG pattern can be helpful for theoretical analysis of reentry waves.     

The biphasic behavior of incoherent feed-forward loops in biomolecular regulatory networks

An incoherent feed-forward loop (FFL) is one of the most-frequently observed motifs in biomolecular regulatory networks. It has been thought that the incoherent FFL is designed simply to induce a transient response shaped by a 'fast activation and delayed inhibition'. We find that the dynamics of various incoherent FFLs can be further classified into two types: time-dependent biphasic responses and dose-dependent biphasic responses. Why do the structurally identical incoherent FFLs play such different dynamical roles? Through computational studies, we show that the dynamics of the two types of incoherent FFLs are mutually exclusive. Following from further computational results and experimental observations, we hypothesize that incoherent FFLs have been optimally designed to achieve distinct biological function arising from different cellular contexts. Additional Supporting Information may be found in the online version of the article.     

Dark quenched matrix metalloproteinase fluorogenic probe for imaging osteoarthritis development in vivo

The early detection of osteoarthritis (OA) is currently a key challenge in the field of rheumatology. Biochemical studies of OA have indicated that matrix metalloproteinase-13 (MMP-13) plays a central role in cartilage degradation. In this study, we describe the potential use of a dark-quenched fluorogenic MMP-13 probe to image MMP-13 in both in vitro and rat models. The imaging technique involved using a MMP-13 peptide substrate, near-infrared (NIR) dye, and a NIR dark quencher. The results from this study demonstrate that the use of a dark-quenched fluorogenic probe allows for the visual detection of MMP-13 in vitro and in OA-induced rat models. In particular, by targeting this OA biomarker, the symptoms of the early and late stages of OA can be readily monitored, imaged, and analyzed in a rapid and efficient fashion. We anticipate that this simple and highly efficient fluorogenic probe will assist in the clinical management of patients with OA, not only for early diagnosis but also to assess individual patient responses to new drug treatments.     

Traceless and Site-specific Attachment of Proteins onto Solid Supports

Many experimental approaches in biology and biophysics, as well as applications in diagnosis and drug discovery, require proteins to be immobilized on solid supports. Protein microarrays, for example, provide a high-throughput format to study biomolecular interactions. The technique employed for protein immobilization is a key to the success of these applications. Recent biochemical developments are allowing, for the first time, the selective and traceless immobilization of proteins generated by cell-free systems without the need for purification and/or reconcentration prior to the immobilization step.     

Transduced human PEP-1-heat shock protein 27 efficiently protects against brain ischemic insult

Reactive oxygen species contribute to the development of various human diseases. Ischemia is characterized by both significant oxidative stress and characteristic changes in the antioxidant defense mechanism. Heat shock protein 27 (HSP27) has a potent ability to increase cell survival in response to oxidative stress. In the present study, we have investigated the protective effects of PEP-1-HSP27 against cell death and ischemic insults. When PEP-1-HSP27 fusion protein was added to the culture medium of astrocyte and primary neuronal cells, it rapidly entered the cells and protected them against cell death induced by oxidative stress. Immunohistochemical analysis revealed that, when PEP-1-HSP27 fusion protein was intraperitoneally injected into gerbils, it prevented neuronal cell death in the CA1 region of the hippocampus in response to transient forebrain ischemia. Our results demonstrate that transduced PEP-1-HSP27 protects against cell death in vitro and in vivo, and suggest that transduction of PEP-1-HSP27 fusion protein provides a potential strategy for therapeutic delivery in various human diseases in which reactive oxygen species are implicated, including stroke.