Possible biomarkers for ionizing radiation exposure in human peripheral blood lymphocytes

Biomarkers to indicate past exposure to radiation have not been entirely satisfactory. Using cDNA microarray hybridization to find new potential biomarkers, we identified highly expressed genes in human peripheral blood lymphocytes (PBLs) after irradiation 1 Gy ex vivo. The present set of radiation markers in PBLs was identified 12 h after radiation. A total of 44 genes were identified. However, when RT-PCR was performed with mRNA from the PBLs of five individuals, only four genes, including TRAIL receptor 2, DRAL (now known as FHL2), cyclin G, and cyclin protein gene, showed greater than 50% agreement between gene induction as detected by microarray analysis and by RT-PCR. When more than 32 donors were tested for the above four genes, greater than 85% agreement was obtained between gene induction measured by microarray analysis and by RT-PCR. There was a linear dose-response relationship between 0.5 and 4 Gy 12 h after irradiation; however, there was less linearity at later times. These results suggested that the relative expression levels of genes such as TRAIL receptor 2, FHL2, cyclin G, and cyclin protein gene in PBLs may provide estimates of radiation exposures.     

Rapid molecular authentication of three medicinal plant species, Cynanchum wilfordii, Cynanchum auriculatum, and Polygonum multiflorum (Fallopia multiflorum), by the development of RAPD-derived SCAR markers and multiplex-PCR

Definitive identification of original plant species is important for standardizing herbal medicine. The herbal medicines Cynanchi Wilfordii Radix (Baekshuoh in Korean and Beishuwu in Chinese) and Polygoni Multiflori Radix (Hashuoh in Korean and Heshuwu in Chinese) are often misidentified in the Korean herbal market due to morphological similarities and similar names. Therefore, we developed a reliable molecular marker for the identification of Cynanchi Wilfordii Radix and Polygoni Multiflori Radix. We used random amplified polymorphic DNA (RAPD) analysis of three plant species, Polygoni multiflorum, Cynanchum wilfordii, and Cynanchum auriculatum, to obtain several species-specific RAPD amplicons. From nucleotide sequences of these RAPD amplicons, we developed six sequence characterized amplification region (SCAR) markers for distinguishing Polygoni Multiflori Radix and Cynanchi Wilfordii Radix. Furthermore, we established SCAR markers for the simultaneous discrimination of the three species within a single reaction by using multiplex-PCR. These SCAR markers can be used for efficient and rapid authentication of these closely related species, and will be useful for preventing the distribution of adulterants.     

Direct activation of Transient Receptor Potential Vanilloid 1(TRPV1) by Diacylglycerol (DAG)

Voltage-gated sodium channels play important roles in modulating dorsal root ganglion (DRG) neuron hyperexcitability and hyperalgesia after peripheral nerve injury or inflammation. We report that chronic compression of DRG (CCD) produces profound effect on tetrodotoxin-resistant (TTX-R) and tetrodotoxin-sensitive (TTX-S) sodium currents, which are different from that by chronic constriction injury (CCI) of the sciatic nerve in small DRG neurons. Whole cell patch-clamp recordings were obtained in vitro from L₄ and/or L₅ dissociated, small DRG neurons following in vivo DRG compression or nerve injury. The small DRG neurons were classified into slow and fast subtype neurons based on expression of the slow-inactivating TTX-R and fast-inactivating TTX-S Na⁺ currents. CCD treatment significantly reduced TTX-R and TTX-S current densities in the slow and fast neurons, but CCI selectively reduced the TTX-R and TTX-S current densities in the slow neurons. Changes in half-maximal potential (V_1/2) and curve slope (k) of steady-state inactivation of Na⁺ currents were different in the slow and fast neurons after CCD and CCI treatment. The window current of TTX-R and TTX-S currents in fast neurons were enlarged by CCD and CCI, while only that of TTX-S currents in slow neurons was increased by CCI. The decay rate of TTX-S and both TTX-R and TTX-S currents in fast neurons were reduced by CCD and CCI, respectively. These findings provide a possible sodium channel mechanism underlying CCD-induced DRG neuron hyperexcitability and hyperalgesia and demonstrate a differential effect in the Na⁺ currents of small DRG neurons after somata compression and peripheral nerve injury. This study also points to a complexity of hyperexcitability mechanisms contributing to CCD and CCI hyperexcitability in small DRG neurons.     

Current concepts of cell-cycle regulation and its relationship to oocyte maturation, fertilization and embryo development

Genetic and biochemical approaches have contributed to an explosion of literature on cell-cycle control. Regulation of the cell-cycle is controlled by a series of kinases and phosphatases. Key control points are during the G(1)-S and G(2)-M transitions. During both transitions, cyclins interact with a specific kinase to allow a cell to pass through that phase. The meiotic maturation of oocytes, fertilization and embryo development are all events influenced by cell-cycle regulation. Understanding cell-cycle control should provide new ways for gamete and embryo biologists to approach culture and development problems.     

An In Vivo C. elegans Model System for Screening EGFR-Inhibiting Anti-Cancer Drugs

The epidermal growth factor receptor (EGFR) is a well-established target for cancer treatment. EGFR tyrosine kinase (TK) inhibitors, such as gefinitib and erlotinib, have been developed as anti-cancer drugs. Although non-small cell lung carcinoma with an activating EGFR mutation, L858R, responds well to gefinitib and erlotinib, tumors with a doubly mutated EGFR, T790M-L858R, acquire resistance to these drugs. The C. elegans EGFR homolog LET-23 and its downstream signaling pathway have been studied extensively to provide insight into regulatory mechanisms conserved from C. elegans to humans. To develop an in vivo screening system for potential cancer drugs targeting specific EGFR mutants, we expressed three LET-23 chimeras in which the TK domain was replaced with either the human wild-type TK domain (LET-23::hEGFR-TK), a TK domain with the L858R mutation (LET-23::hEGFR-TK[L858R]), or a TK domain with the T790M-L858R mutations (LET-23::hEGFR-TK[T790M-L858R]) in C. elegans vulval cells using the let-23 promoter. The wild-type hEGFR-TK chimeric protein rescued the let-23 mutant phenotype, and the activating mutant hEGFR-TK chimeras induced a multivulva (Muv) phenotype in a wild-type C. elegans background. The anti-cancer drugs gefitinib and erlotinib suppressed the Muv phenotype in LET-23::hEGFR-TK[L858R]-expressing transgenic animals, but not in LET-23::hEGFR-TK[T790M-L858R] transgenic animals. As a pilot screen, 8,960 small chemicals were tested for Muv suppression, and AG1478 (an EGFR-TK inhibitor) and U0126 (a MEK inhibitor) were identified as potential inhibitors of EGFR-mediated biological function. In conclusion, transgenic C. elegans expressing chimeric LET-23::hEGFR-TK proteins are a model system that can be used in mutation-specific screens for new anti-cancer drugs.     

Proteoglycan isolated from Phellinus linteus inhibits tumor growth through mechanisms leading to an activation of CD11c+CD8+ DC and type I helper T cell-dominant immune state

Dendritic cells (DC) are known to not only induce the activation of T cells, but are also associated with the polarization of T cells. This study investigated whether or not proteoglycan (PG) isolated from Phellinus linteus induces the phenotypic and functional maturation of CD11c+ DC in vitro and in vivo. PG was found to induce the phenotypic and functional maturation of bone marrow-derived DC via Toll-like receptors (TLR) 2 and 4 in vitro. Administration of PG in vivo strongly inhibited the MCA-102 tumor growth and increase in vivo. The ratio of CD8+ DC to CD8- DC increased, and PG enhanced IL-12 and IFN-gamma production, and expression of surface molecules including major histocompatibility complexes (MHC) classes I, MHC II, CD80, and CD86 in MCA-102-challenged mice. PG also caused a marked increase in the production of Th (helper T cells)-1 cytokine (IFN-gamma) and a decrease in the production of Th-2 cytokine (IL-4) by splenic cells and inguinal lymph node cells in MCA-102 tumor-bearing mice. Furthermore, PG stimulated the proliferation of CD4+ and CD8+ T cells. In addition, a combination of PG and tumor lysate-pulsed DC inhibited completely the growth of MCA-102 cells in tumor-bearing mice. These results indicate that the administration of PG inhibited the tumor growth through a mechanism leading to a Th-1 dominant immune state and the activation of CD11cCD8+ DC.     

The Role in Ozone Phytotoxicity of the Evolution of Ethylene upon Induction of 1-Aminocydopropane-1-carboxylic Acid Synthase by Ozone Fumigation in Tomato Plants

The rate of evolution of ethylene by tomato plants was rapidlyincreased by O₃ fumigation. The time course of the increasein 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activitywas the same as that in the rate of evolution of ethylene, suggestingthat ACC synthase activity might be a rate-limiting step inthe evolution of ethylene that is caused by O₃ fumigation. Therate of the O₃-induced evolution of ethylene was increased bythe application of ACC to tomato plants, suggesting the involvementof ACC oxidase in the O₃-induced evolution of ethylene. Treatmentof plants with tiron inhibited the evolution of ethane, butnot of ethylene. These results indicated that evolution of ethylenein O₃-treated tomato plants might result from enzymatic reactionscatalyzed by both ACC synthase and ACC oxidase, but not fromstimulation by O₃ of the peroxidation of lipids mediated byfree radicals. Pretreatment of leaves with aminoethoxyvinylglycine (AVG), aninhibitor of ACC synthase, significantly inhibited the evolutionof ethylene that was induced by O₃ and concomitantly reducedthe extent of O₃-induced visible damage to leaves. Treatmentwith 2,5-norbonadiene, an inhibitor of the action of ethylene,strongly reduced the extent of visible damage caused by O₃,even though it did not suppress the evloution of ethylene. Theseresults indicate that ethylene acts on certain metabolic processesto cause visible damage. (Received September 7, 1995; Accepted December 18, 1995)     

Value of Computerized 3D Shape Analysis in Differentiating Encapsulated from Invasive Thymomas

ObjectivesTo retrospectively investigate the added value of quantitative 3D shape analysis in differentiating encapsulated from invasive thymomas.ResultsSignificant differences were observed between encapsulated and invasive thymomas, in terms of cystic changes (p=0.004), sphericity (p=0.016), and discrete compactness (p=0.001). Subsequent binary logistic regression analysis revealed that absence of cystic change (adjusted odds ratio (OR) = 6.636; p=0.015) and higher discrete compactness (OR = 77.775; p=0.012) were significant differentiators of encapsulated from invasive thymomas. ROC analyses revealed that the addition of 3D shape analysis to clinical and CT features (AUC, 0.955; 95% CI, 0.935–0.975) provided significantly higher performance in differentiating encapsulated from invasive thymomas than clinical and CT features (AUC, 0.666; 95% CI, 0.626–0.707) (p<0.001).ConclusionAddition of 3D shape analysis, particularly discrete compactness, can improve differentiation of encapsulated thymomas from invasive thymomas.     

Seroprevalence of toxoplasmosis in the residents of Cheju island, Korea

This study was performed to evaluate the epidemiological status of toxoplasmosis among the residents of Cheju island. The sera of local students from 18 high schools (boys 2110, girls 2460) and those of adults (474 admitted to Cheju Chungang General Hospital) were collected and checked for the IgG antibody titers against Toxoplasma gondii. Serum samples collected from both the students and adults showed sero-positive rate of 5.5% and 12.9%, respectively. Although the rates were not significantly different between the sexes (5.4% for the boys and 5.5% for the girls attending school), the geographical difference showed a significant difference between the urban (4.6-6.9%) and rural areas (5.6-8.8%) (p < 0.05). Based on the high positive rates, it should be necessary to control toxoplasmosis in Cheju island.