269 EXPRESSION OF TANDEM-PORE DOMAIN K+ CHANNELS IN BOVINE OOCYTES AND PRE-IMPLANTATION EMBRYOS

Tandem-pore domain K+ (K2P) channels that contribute to setting the resting membrane potential of excitable and nonexcitable cells are expressed in many kinds of cells and tissues. Recent studies have shown that TASK [TWIK (Tandem of P domains in Weak Inward rectifying K+ channels)-related acid-sensitive K+ channels] and TREK (TWIK-Related K+ channels), members of K2P channel family that are involved in a variety of cellular functions, are expressed in human myometrium, placenta, and cytotrophoblast cells. However, their expression in bovine oocytes and embryos has not yet been reported. In this study, we examined whether TASK and TREK channels are expressed in bovine immature (germinal vesicle-stage) and mature (metaphase II-stage) oocytes and in pre-implantation (2-cell- and 16-cell-stage) embryos using RT-PCR and immunocytochemistry. RT-PCR data showed that TASK-1, TASK-3, TREK-1, TREK-2, and TRAAK channels were expressed in bovine immature and mature oocytes. Interestingly, the expression levels of TREK channels were 2-fold higher than those of TASK channels as judged by semiquantitative RT-PCR and real-time PCR with cDNA synthesized from 50 individual immature and mature oocytes (P < 0.05, n = 4). Intensity of genes was normalized with respect to that of GAPDH. Consistent with RT-PCR data, immunocytochemical data showed that TASK-1, TASK-3, TREK-1, TREK-2, and TRAAK channels were expressed in bovine immature and mature oocytes. The fluorescence intensity of TREK channels was higher than that of TASK channels (P < 0.05, n = 5). TASK and TREK channels were also expressed in pre-implantation embryos. Of TREK channels, the TREK-2 channel was strongly expressed in immature and mature oocytes and in pre-implantation embryos (P < 0.05, n = 5). For statistics, Student's t-test was used, with P < 0.05 as the criterion for significance. Our results show that TASK-1, TASK-3, TREK-1, TREK-2, and TRAAK channels were expressed in bovine immature and mature oocytes and pre-implantation embryos. These results suggest that TASK and TREK channels could be involved in various physiological processes in mammalian oocytes and embryos.

237 POTASSIUM CONCENTRATION AND mRNA LEVELS OF POTASSIUM CHANNELS DECREASED IN CYSTIC OVARIAN FOLLICLE FLUID

Cystic ovarian follicle (COF) is one of the most frequently diagnosed ovarian diseases and a major cause of reproductive failure in cattle. Despite an abundance of reports on this subject, the exact pathogenesis of COF still remains unclear. It is generally accepted that disruption of the hypothalmo-pituitary-gonadal axis, by endogenous and/or exogenous factors, causes cystic formation. We here examined whether ion concentration and expression of ion channels are altered in the follicle fluid derived from a Korean native cow with COF. In an ovary with a cystic follicle, granulosa cell layers were exfoliated; the theca interna was thinner than that in an ovary without cystic follicle, based on histological examination. Concentrations of K+, Na+, and Cl- in COF fluid (COFF) were 10.4 � 3.5 mM, 138 � 12 mM, and 104.9 � 7.0 mM, respectively. In COFF, K+ concentration showed a significant difference from the value observed in normal follicle fluid (NFF) (P < 0.05; NFF: 10.4 � 3.5 mM vs. COFF: 6.2 � 0.8 mM). The total numbers of follicles observed (normal, 3–5 mm in diameter vs. COF, 20–30 mm in diameter) were 200 and 20 in normal and COF, respectively. To compare mRNA expression of K+ channels, we performed semiquantitative RT-PCR using follicle fluid and ovaries with or without cystic follicles. RT-PCR showed that mRNA levels of TASK channels (TASK-1, TASK-3, and TASK-5) decreased by 50% in COFF and an ovary with cystic follicles compared to NFF and a normal ovary. TASK channels are involved in apoptosis of mammalian cells. Our results suggest that potassium may play an important role in the pathogenesis of COF.

334 DNA SYNTHESIS DURING THE FIRST CELL CYCLE OF PORCINE OOCYTES FOLLOWING DIFFERENT ACTIVATION TREATMENTS

Inhibitors of protein synthesis and phosphorylation have been widely used for oocyte activation and have been reported to induce abnormalities in nuclear ploidy due to aberrant DNA synthesis (DNAS). The present experiment was designed to compare the DNAS during the first cell cycle of porcine parthenotes following different activation treatments. Cumulus–oocyte complexes were cultured in TCM-199 supplemented with 0.5 �g mL-1 LH and FSH, 10 ng mL-1 EGF, and 0.1% PVA for 22 h, and additionally cultured in media without LH and FSH for 22 h. MII oocytes were then electrically pulsed twice in 0.28 M mannitol containing 0.05 mM CaCl2 and 0.1 mM MgSO4 at 1.8 kV cm-1 for 30 �s (group 1), followed by 7.5 �g mL-1 cytochalasin B (CCB, group 2), 10 �g mL-1 cycloheximide (CHX, group 3), or 1.9 mM 6-dimethylaminopurine (6-DMAP, group 4) for 3 h. Eggs were incubated with 100 �M 5-bromo-222-deoxyuridine (BrdU) for 1 h at 0, 2, 4, 6, 8, 10, and 12 h after activation to evaluate DNAS (Adenot et al. 1997 Development 124, 4615–4625) by determining the BrdU signal under a fluorescence microscope. Experiments were replicated 4 times; results were expressed as mean � SD and analyzed using one-way ANOVA by SPSS 10.0. The percentage of DNAS was calculated by dividing the number of BrdU-positive eggs by the total number of eggs used. DNAS in groups 1, 3, and 4 initiated at 2–3 h post-activation (hpa) but at 4–5 hpa in group 2. In group 1, DNAS was faint until 3 hpa, gradually increasing thereafter until 11 hpa (20.7 � 19.6, 29.4 � 17.0, 41.3 � 16.7, and 64.4 � 6.2, at 4–5, 6–7, 8–9, and 10–11 hpa, respectively). There was a significant (P < 0.05) increase in DNAS at 10–11 h, but a significant (P < 0.05) decrease (34.3 � 6.4) at 12–13 hpa. In groups 2 and 3, after 4–5 hpa, DNAS gradually increased until 7 h (6.2 � 1.4 and 29.8 � 16.6 at 4–5 hpa, and 21.1 � 13.7 and 40.0 � 18.7 at 6–7 hpa, respectively), but a DNAS peak was observed at 8–9 h (44.6 � 9.0) in group 2 and at 10–11 h (40.5 � 22.1) in group 3. Interestingly, group 4 parthenotes showed a different DNAS pattern compared with other groups, as it started at 2–3 hpa (24.8 � 11.7), reached a significantly (P < 0.05) high level at 4–5 hpa (56.3 � 9.0), and gradually decreased at 6–7 hpa (42.7 � 10.3) until 12–13 hpa (29.5 � 14.9). In conclusion, CCB, CHX, and 6-DMAP used for oocyte activation exhibited different patterns of DNA synthesis during the first cell cycle of porcine parthenotes. Therefore, further experiments are required to evaluate the molecular signaling that regulates DNAS, embryonic developmental velocity, and ploidy of 2-cell parthenotes.

Meta- and pooled analysis of GSTT1 and lung cancer: a HuGE-GSEC review

Lung cancer is the most common malignancy in the Western world, and the main risk factor is tobacco smoking. Polymorphisms in metabolic genes may modulate the risk associated with environmental factors. The glutathione S-transferase theta 1 gene (GSTT1) is a particularly attractive candidate for lung cancer susceptibility because of its involvement in the metabolism of polycyclic aromatic hydrocarbons found in tobacco smoke and of other chemicals, pesticides, and industrial solvents. The frequency of the GSTT1 null genotype is lower among Caucasians (10-20%) than among Asians (50-60%). The authors present a meta- and a pooled analysis of case-control, genotype-based studies that examined the association between GSTT1 and lung cancer (34 studies, 7,629 cases and 10,087 controls for the meta-analysis; 34 studies, 7,044 cases and 10,000 controls for the pooled analysis). No association was observed between GSTT1 deletion and lung cancer for Caucasians (odds ratio (OR) = 0.99, 95% confidence interval (CI): 0.87, 1.12); for Asians, a positive association was found (OR = 1.28, 95% CI: 1.10, 1.49). In the pooled analysis, the odds ratios were not significant for either Asians (OR = 0.97, 95% CI: 0.83, 1.13) or Caucasians (OR = 1.09, 95% CI: 0.99, 1.21). No significant interaction was observed between GSTT1 and smoking on lung cancer, whereas GSTT1 appeared to modulate occupational-related lung cancer.

SULT1E1 genetic polymorphisms modified the association between phytoestrogen consumption and bone mineral density in healthy Korean women

Sulfotransferase 1E1 (SULT1E1) catalyze estrogen into sulfate conjugation and is involved in the metabolism of phytoestrogen. A community-based cross-sectional study was conducted on 397 Korean women, to evaluate the association between genetic polymorphisms of SULT1E1 and bone mineral density (BMD) and the combined effect of the genetic polymorphism and phytoestrogen intake for BMD in Korean women. BMDs of the distal radius and the calcaneus were measured by dual-energy X-ray absorptiometry. Genotypes of SULT1E1 IVS1-447 C>A, IVS4-1653 T>C, and *959 G>A were determined by the 5'-nuclease assay (TaqMan). Phytoestrogen intake was estimated by a food-frequency questionnaire validated against multiple 24-hour recalls. Women with the SULT1E1 *959 GG genotype had a 4.5% lower BMD at the distal radius (P (trend )= 0.05) and a 7.9% lower BMD at the calcaneus compared to those with AA genotype (P (trend) < 0.01), whereas the SULT1E1 IVS1-447 CC genotype and IVS4-1653 TT genotype were not associated with BMD. There was no significant trend of BMD with the numbers of CTG-containing haplotypes, but calcaneal BMDs significantly differed between SULT1E1 CTA-CTA haplotype and CTG-CCA haplotype (P < 0.05). When stratified by SULT1E1 genotype, the correlation between phytoestrogen consumption and BMD at the calcaneus was noteworthy in women with SULT1E1 *959 GG genotype (r = 0.25, P = 0.01) or SULT1E1 IVS 4-1653 TT genotype (r = 0.15, P = 0.02). This trend remained significant only in postmenopausal women (r = 0.36, P = 0.01) after multiple testing was corrected by the false discovery rate method. In conclusion, the genetic polymorphism of SULT1E1 *959 G > A was associated with BMD at the distal radius and calcaneus, and the association between phytoestrogen consumption and calcaneal BMD might be modified by this genetic polymorphism.

A novel acid-sensitive K+ channel in rat dorsal root ganglia neurons

Recent studies have suggested that acid-sensitive background K+ channels such as TASK-1 and TASK-3, members of two-pore domain K+ (K2P) channel family, express and contribute to extracellular acidification-induced responses in dorsal root ganglia (DRG) neurons. However, it has remained to address whether other acid-sensitive background K+ channels are functionally expressed in DRG neurons. Here we characterized biophysical and pharmacological properties of a novel acid-sensitive background K+ channel in DRG neurons isolated from neonatal rats. We recorded an 80-pS K+ channel with a weak inward rectification current-voltage relationship in cell-attached patches in 150mM KCl bath solution. The 80-pS K+ channel was inhibited by extracellular low pH (pHo 6.3). Interestingly, the channel was similar to TASK-2 cloned from mouse and rat in biophysical and pharmacological properties. However, extracellular alkaline condition which activates TASK-2 channel, failed to activate the 80-pS K+ channel. Lidocaine and quinine more inhibited the channel activity of 80-pS K+ channel than that of TASK-2 channel. Our results suggest that the acid-sensitive 80-pS K+ channels may regulate resting membrane potential and may play a critical role in various processes such as cell metabolism, pH, and pain sensation in DRG neurons.

CagA-producing Helicobacter pylori and increased risk of gastric cancer: a nested case-control study in Korea

In a nested-case control study of 100 cases of gastric cancer and 400 matched controls in relation to virulence factors of Helicobacter pylori in a Korean cohort, CagA seropositivity was significantly associated with a higher risk of gastric cancer among H. pylori-infected subjects (OR=3.57, 95% CI 1.05–12.14).

TREK-2 (K2P10.1) and TRESK (K2P18.1) are major background K+ channels in dorsal root ganglion neurons

Dorsal root ganglion (DRG) neurons express mRNAs for many two-pore domain K+ (K2P) channels that behave as background K+ channels. To identify functional background K+ channels in DRG neurons, we examined the properties of single-channel openings from cell-attached and inside-out patches from the cell bodies of DRG neurons. We found seven types of K+ channels, with single-channel conductance ranging from 14 to 120 pS in 150 mM KCl bath solution. Four of these K+ channels showed biophysical and pharmacological properties similar to TRESK (14 pS), TREK-1 (112 pS), TREK-2 (50 pS), and TRAAK (73 pS), which are members of the K2P channel family. The molecular identity of the three other K+ channels could not be determined, as they showed low channel activity and were observed infrequently. Of the four K2P channels, the TRESK-like (14 pS) K+ channel was most active at 24°C. At 37°C, the 50-pS (TREK-2 like) channel was the most active and contributed the most (69%) to the resting K+ current, followed by the TRESK-like 14-pS (16%), TREK-1-like 112-pS (12%), and TRAAK-like 73-pS (3%) channels. In DRG neurons, mRNAs of all four K2P channels, as well as those of TASK-1 and TASK-3, were expressed, as judged by RT-PCR analysis. Our results show that TREKs and TRESK together contribute >95% of the background K+ conductance of DRG neurons at 37°C. As TREKs and TRESK are targets of modulation by receptor agonists, they are likely to play an active role in the regulation of excitability in DRG neurons.

Mechanism of inhibition of TREK-2 (K2P10.1) by the Gq-coupled M3 muscarinic receptor

TREK-2 is a member of the two-pore domain K(+) channel family and provides part of the background K(+) current in many types of cells. Neurotransmitters that act on receptors coupled to G(q) strongly inhibit TREK-2 and thus enhance cell excitability. The molecular basis for the inhibition of TREK-2 was studied. In COS-7 cells expressing TREK-2 and M(3) receptor, acetylcholine (ACh) applied to the bath solution strongly inhibited the whole cell current, and this was markedly reduced in the presence of U-73122, an inhibitor of PLC. The inhibition was also observed in cell-attached patches when ACh was applied to the bath solution. In inside-out patches, direct application of guanosine 5'-O-(3-thiotriphosphate) (10 microM), Ca(2+) (5 microM), or diacylglycerol (DAG; 10 microM) produced no inhibition of TREK-2 in >75% of patches tested. Phosphatidic acid, a product of DAG kinase, had no effect on TREK-2. Pretreatment of cells with 20 microM wortmannin, an inhibitor of phosphatidylinositol kinases, did not affect the inhibition or the recovery from inhibition of TREK-2, suggesting that phosphatidylinositol 4,5-bisphosphate depletion did not mediate the inhibition. Pretreatment of cells with a protein kinase C inhibitor (bisindolylmaleimide, 10 microM) markedly inhibited ACh-induced inhibition of TREK-2. Mutation of two putative PKC sites (S326A, S359C) abolished inhibition by ACh. Mutation of these amino acids to aspartate to mimic the phosphorylated state resulted in diminished TREK-2 current and no inhibition by ACh. These results suggest that the agonist-induced inhibition of TREK-2 via M(3) receptor occurs primarily via PKC-mediated phosphorylation.

Single-nucleotide polymorphisms and haplotypes of bone morphogenetic protein genes and peripheral bone mineral density in young Korean men and women

Bone morphogenetic proteins (BMPs) play critical roles in osteoblast differentiation. To investigate the association between common single-nucleotide polymorphisms (SNPs) of BMPs and bone mineral density (BMD), a cross-sectional study was conducted in healthy Korean men (n = 237) and women (n = 276) aged 20-39 years. Calcaneus and distal radius BMD were measured by dual energy X-ray absorptiometry. SNPs of BMP2 (-1103C > A, c.584G > A, IVS1-2744A > G, c.893T > A), BMP4 (c.712T > C, IVS1-160C > T), and BMP6 (c.1283C > G, IVS4-6838A > G, IVS5 + 24C > T) were determined using the 5'-nuclease assay. Significant associations were observed between BMP2 c.584G > A, c.893T > A genotypes and male calcaneus as well as female distal radius BMD. Men with the BMP2 c.893 AA genotype had a 16% higher BMD at the calcaneus (P for trend = 0.014), whereas women with this genotype had a 7% lower BMD at the distal radius than the other genotypes (P for trend = 0.010). A significant association was also observed between BMP4 IVS1-160C > T and male calcaneus BMD (P for trend = 0.024). When the association between haplotypes and BMD was investigated, the AAGA haplotype of BMP2 was significantly associated with low bone mass in female distal radius (P for trend = 0.013). These results suggested that one or more SNPs of BMP2 and BMP4 are associated with peripheral BMD in Korean men and women. However, this association is dependent on anatomical sites and gender. Thus, larger studies with complete coverage of SNPs are needed in the future.

An endogenous acid-sensitive K+ channel expressed in COS-7 cells

COS-7 cells originally isolated from monkey kidney and used in many transfection studies were found to express a background K+ channel and therefore, its biophysical and pharmacological properties were examined. In cell-attached patches, a 32-pS K+ channel with a linear current-voltage relationship could be recorded. The open probability was highly voltage-dependent, with greater channel activity at depolarized potentials. The channel was markedly sensitive to changes in extracellular pH (pH(o)), showing a 70+/-10% inhibition by changing the pH(o) from 7.3 to 6.3. Arachidonic acid (5 microM) augmented channel activity 12-fold. Applying negative pressure (-40 mmHg) to the membrane patch also increased channel activity by 4-fold. These results show that COS-7 cells express a K+ channel with unique properties that must be considered when using these cells as transfection system.

MTH1, an oxidized purine nucleoside triphosphatase, protects the dopamine neurons from oxidative damage in nucleic acids caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

We previously reported that 8-oxoguanine (8-oxoG) accumulates in the cytoplasm of dopamine neurons in the substantia nigra of patients with Parkinson's disease and the expression of MTH1 carrying an oxidized purine nucleoside triphosphatase activity increases in these neurons, thus suggesting that oxidative damage in nucleic acids is involved in dopamine neuron loss. In the present study, we found that levels of 8-oxoG in cellular DNA and RNA increased in the mouse nigrostriatal system during the tyrosine hydroxylase (TH)-positive dopamine neuron loss induced by the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MTH1-null mice exhibited a greater accumulation of 8-oxoG in mitochondrial DNA accompanied by a more significant decrease in TH and dopamine transporter immunoreactivities in the striatum after MPTP administration, than in wild-type mice. We thus demonstrated that MTH1 protects the dopamine neurons from oxidative damage in the nucleic acids, especially in the mitochondrial DNA of striatal nerve terminals of dopamine neurons.

Genetic polymorphisms of OPG, RANK, and ESR1 and bone mineral density in Korean postmenopausal women

To evaluate the effects of genetic polymorphisms of OPG, RANK, and ESR1, which regulate osteoclastogenesis, on bone mineral density (BMD), a cross-sectional study was conducted in 650 Korean postmenopausal women. BMDs of the distal radius and the calcaneus were measured by dual energy X-ray absorptiometry (DXA). Genetic polymorphisms of OPG 163 A > G, 1181 G > C; RANK 421 C > T, 575 T > C; and ESR1 1335 C > T, 2142 G > A were determined by matrix-assisted laser desorption/ionization-time of flight (MALDI-ToF) mass spectrometry. The differences between the BMDs of the genotypes of OPG, RANK, and ESR1 were analyzed by multiple linear regression model adjusted for age and body mass index. Women with the OPG 1181 CC genotype had higher BMDs at the distal radius (7%) and calcaneus (10%) than those with the GG genotype; and these differences were statistically significant (P = 0.001 and P = 0.007, respectively). A significant association was also observed between RANK 575 T > C and calcaneus BMD (P for trend = 0.017). No significant association was observed between BMDs and the polymorphisms of ESR1. The association between OPG 1181 G > C and BMD was profound in subjects with the RANK 575 TT or ESR1 2142 GG genotypes; women with OPG 1181 CC had higher BMDs at the distal radius (11%) and calcaneus (11%) than those with OPG 1181 GG only in women with RANK 575 TT genotype (P = 0.002 and P = 0.021, respectively). These results suggest that OPG genetic polymorphisms, especially with the RANK 575 TT or ESR1 2142 GG genotypes, are related to low BMD in postmenopausal Korean women.

First measurement of the transverse spin asymmetries of the deuteron in semi-inclusive deep inelastic scattering

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.

A nested case-control study of the association of Helicobacter pylori infection with gastric adenocarcinoma in Korea

In a nested case–control study of 86 cases of gastric adenocarcinoma in relation to Helicobactor pylori infection in the Korean Multi-center Cancer Cohort, the H. pylori IgG seropositivity was 83.7% and that of the 344 matched controls was 80.8%, with a matched odds ratio for H. pylori infection of 1.06 (95% CI, 0.80–1.40).

Detection of the steroidogenic acute regulatory protein, StAR, in human liver cells

Overexpressing StAR (a mitochondrial cholesterol transporter) increases (>5-fold) the rate of 27-hydroxylation of cholesterol and the rates of bile acid synthesis in primary rat hepatocytes; suggesting that the transport of cholesterol into mitochondria is rate-limiting for bile acid biosynthesis via the CYP27A1 initiated 'acidic' pathway. Our objective was to determine the level of StAR expression in human liver and whether changes in StAR would correlate with changes in CYP27A1 activity/bile acid synthesis rates in human liver tissues. StAR mRNA and protein were detected in primary human hepatocytes and HepG2 cells by RT-PCR/Northern analysis and by Western analysis, respectively. In immunocompetition assays, liver StAR was competed away with the addition of purified human adrenal StAR. Overexpressing CYP27A1 in both cell types led to >2-fold increases in liver StAR concentration. StAR protein levels also increased approximately 2-fold with the addition of 27-hydroxycholesterol to HepG2 cell culture medium. Overexpressing StAR increased the rates of 27-hydroxylation of cholesterol/bile acid synthesis in both cell lines and increased intracellular levels of 27-hydroxycholesterol. In conclusion, human liver cells contain regulable StAR protein whose level of expression appears capable of regulating cellular cholesterol homeostasis, representing a potential therapeutic target in the management of hyperlipidemia.

First results from the CERN axion solar telescope

Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)<1.16x10(-10) GeV-1 at 95% C.L. for m(a) less, similar 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses.

Trigemino-cervical response in patients with amyotrophic lateral sclerosis

PURPOSE

The trigemino-cervical response (TCR) was investigated in the patients with amyotrophic lateral sclerosis (ALS) to evaluate its effect for disclosing the bulbar involvement in this disorder.

METHODS

We studied 100 normal subjects and 45 patients with ALS. In all normal subjects, stimulation of the infraorbital nerve on one side produced bilateral short latency waves, which consisted of a positive/negative wave described with the mean peak latency (P20/N30). The mean square root of the ratio between the amplitude of P20/N30 and the mean rectified surface EMG activity preceding the stimulus was described by A value.

RESULTS

The latency of P20 in controls was 18.5 +/- 1.4 ms, N30 was 28.8 +/- 2.8 ms, and the A value was 1.6 +/- 0.5, respectively. In ALS patients, twelve showed absent, seventeen were delayed in the latencies, six were above normal asymmetry on two sides, and ten showed normal. The latency of P20 in ALS patients was 22.9 +/- 9.4 ms, N30 was 33.7 +/- 11.2 ms, and the A value was 1.5 +/- 0.8, respectively. The parameters of the latencies of TCR between ALS patients and the normal controls were statistically different (P < 0.05).

CONCLUSIONS

TCR can be reliably measured in all normal subjects and help in disclosing lower brainstem lesions in ALS patients, even without bulbar symptoms.

Thermosensitivity of the two-pore domain K+ channels TREK-2 and TRAAK

TREK-1, TREK-2 and TRAAK are members of the two-pore domain K+ (K2P) channel family and are activated by membrane stretch and free fatty acids. TREK-1 has been shown to be sensitive to temperature in expression systems. We studied the temperature-sensitivity of TREK-2 and TRAAK in COS-7 cells and in neuronal cells. In transfected COS-7 cells, TREK-2 and TRAAK whole-cell currents increased approximately 20-fold as the bath temperature was raised from 24 degrees C to 42 degrees C. Similarly, in cell-attached patches of COS-7 cells, channel activity was very low, but increased progressively as the bath temperature was raised from 24 degrees C to 42 degrees C. The thresholds for activation of TREK-2 and TRAAK were approximately 25 degrees C and approximately 31 degrees C, respectively. Other K2P channels such as TASK-3 and TRESK-2 were not significantly affected by an increase in temperature from 24 degrees C to 37 degrees C. When the C-terminus of TREK-2 was replaced with that of TASK-3, its sensitivity to free fatty acids and protons was abolished, but the mutant could still be activated by heat. At 37 degrees C, TREK-1, TREK-2 and TRAAK were sensitive to arachidonic acid, pH and membrane stretch in both cell-attached and inside-out patches. In cerebellar granule and dorsal root ganglion neurones, TREK-1, TREK-2 and TRAAK were generally inactive in the cell-attached state at 24 degrees C, but became very active at 37 degrees C. In cell-attached patches of ventricular myocytes, TREK-1 was also normally closed at 24 degrees C, but was active at 37 degrees C. These results show that TREK-2 and TRAAK are also temperature-sensitive channels, are active at physiological body temperature, and therefore would contribute to the background K+ conductance and regulate cell excitability in response to various physical and chemical stimuli.

Physical and functional interaction between BH3-only protein Hrk and mitochondrial pore-forming protein p32

Bcl-2 homology domain (BH) 3-only proteins of the proapoptotic Bcl-2 subfamily play a key role as initiators of mitochondria-dependent apoptosis. To date, at least 10 mammalian BH3-only proteins have been identified, and it is now being realized that they have different roles and mechanisms of regulation in the transduction of apoptotic signals to mitochondria. Hrk/DP5 is one of the mammalian BH3-only proteins implicated in a variety of physiological and pathological apoptosis, yet the molecular mechanism involved in Hrk-mediated apoptosis remains poorly understood. In an attempt to identify cellular proteins participating in Hrk-mediated apoptosis, we have conducted yeast two-hybrid screening for Hrk-interacting proteins and isolated p32, a mitochondrial protein that has been shown to form a channel consisting of its homotrimer. In vitro binding, co-immunoprecipitation, as well as immunocytochemical analyses verified specific interaction and colocalization of Hrk and p32, both of which depended on the presence of the highly conserved C-terminal region of p32. Importantly, Hrk-induced apoptosis was suppressed by the expression of p32 mutants lacking the N-terminal mitochondrial signal sequence (p32(74-282)) and the conserved C-terminal region (p32 (1-221)), which are expected to inhibit binding of Hrk competitively to the endogenous p32 protein and to disrupt the channel function of p32, respectively. Furthermore, small interfering RNA-mediated knockdown of p32 conferred protection against Hrk-induced apoptosis. Altogether, these results suggest that p32 may be a key molecule that links Hrk to mitochondria and is critically involved in the regulation of Hrk-mediated apoptosis.

Inheritance of resistance to zucchini yellow mosaic virus and watermelon mosaic virus in watermelon

High resistance to zucchini yellow mosaic virus-China strain (ZYMV-CH) and moderate resistance to watermelon mosaic virus (WMV) were found in a selection of PI 595203 (Citrullus lanatus var. lanatus), an Egusi type originally collected in Nigeria. Mixed inoculations showed primarily that these two viruses have no cross-protection. This fact may explain the high frequency of mixed infection often observed in commercial fields. When plants were inoculated with a mixture of the two viruses, the frequency of plants resistant to ZYMV was lower than expected, indicating that WMV infection may reduce the ability of a plant to resist ZYMV. We studied inheritance of resistance to ZYMV-CH and WMV, using crosses between a single-plant selection of PI 595203 and the ZYMV-susceptible watermelon inbreds 9811 and 98R. According to virus ratings of the susceptible parents, the resistant parent, and the F1, F2, and BC1 generations, resistance to ZYMV-CH was conferred by a single recessive gene, for which the symbol zym-CH is suggested. The high tolerance to WMV was controlled by at least two recessive genes.

Functional expression of TREK-2 in insulin-secreting MIN6 cells

Insulin secretion from pancreatic beta cells is partly regulated by cell membrane potential. Background K+ channels that stabilize the resting membrane potential would suppress excitability and insulin secretion. Recent studies show that members of the two-pore domain K+ (K2P) channel family behave as background K+ channels in many excitable cells. Therefore, the expression of K2P channels was studied in insulin-secreting MIN6 cells. Reverse transcriptase PCR showed that, among nine K2P channels tested, TASK-1, TASK-2, TASK-3, TREK-2, and TRESK-2 were expressed in MIN6 cells. Cell-attached recordings on MIN6 cells revealed five types of K+ channels that were open at rest. Two were ATP-sensitive and Ca2+-activated K+ channels, as judged by their sensitivity to ATP and Ca2+, respectively, and single-channel conductance. Among five K2P channels, only TREK-2 could be clearly identified in MIN6 cells. The molecular identity of two other K+ channels is not yet known. TREK-2 in MIN6 cells was activated by arachidonic acid, membrane stretch, and low pH solution (pH 5.8). Arachidonic acid increased Ba2+-sensitive whole-cell current in MIN6 cell. These results suggest that TREK-2 contributes to the background K+ conductance in MIN6 cells, and may regulate depolarization-induced secretion of insulin.

Risk behaviours and benign prostatic hyperplasia

OBJECTIVE

To identify risk factors for benign prostatic hyperplasia (BPH).

SUBJECTS AND METHODS

Medical history data, including reported urological conditions and treatments, and risk factor data were collected from 34 694 participants in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, a randomized controlled trial designed to evaluate methods for the early detection of cancer.

RESULTS

Asian men had the lowest risks (odds ratio, 95% confidence interval) for nocturia (0.7, 0.5-0.9), physician-diagnosed BPH (0.3, 0.2-0.5) and transurethral prostatectomy (TURP, 0.2, 0.1-0.6), while risks for Whites and Blacks were similar for most measures of BPH. Greater alcohol intake was associated with decreased nocturia (P trend = 0.002), BPH (P trend < 0.001) and TURP (P trend < 0.001). Current tobacco use was associated with decreased nocturia (0.8, 0.7-0.9), BPH (0.7, 0.6-0.8) and TURP (0.6, 0.4-0.8) but dose-response patterns were weak.

CONCLUSION

Asian-Americans have the lowest risk of clinical BPH. Alcohol and possibly cigarettes are related to a lower risk for BPH.

Functional expression of TRESK-2, a new member of the tandem-pore K+ channel family

A new member of the tandem-pore K+ (K(2P)) channel family has been isolated from mouse testis complementary DNA. The new K(2P) channel was named TRESK-2, as its amino acid sequence shares 65% identity with that of TRESK-1. Mouse TRESK-2 is a 394-amino acid protein and possesses four putative transmembrane segments and two pore-forming domains. TRESK-2 has a long cytoplasmic domain joining the second and third transmembrane segments and a short carboxyl terminus. In the rat, TRESK-2 mRNA transcripts were expressed abundantly in the thymus and spleen and at low levels in many other tissues, including heart, small intestine, skeletal muscle, uterus, testis, and placenta, as judged by Northern blot analysis. TRESK-2 mRNA was also expressed in mouse and human tissues. In COS-7 cells transfected with TRESK-2 DNA, a time-independent and noninactivating K+-selective current was recorded. TRESK-2 was insensitive to 1 mm tetraethylammonium, 100 nm apamin, 1 mm 4-aminopyridine, and 10 microm glybenclamide. TRESK-2 was inhibited by 10 microm quinidine, 20 microm arachidonate and acid (pH 6.3) at 49, 43, and 23%, respectively. Single channel openings of TRESK-2 showed marked open channel noise. In symmetrical 150 mm KCl, the current-voltage relationship of TRESK-2 was slightly inwardly rectifying, with the single channel conductance 13 picosiemens (pS) at +60 mV and 16 pS at -60 mV. In inside-out patches, TRESK-2 was unaffected by the intracellular application of 10 microm guanosine 5'-O-(thiotriphosphate). These results show that TRESK-2 is a functional member of the K(2P) channel family and contributes to the background K+ conductance in many types of cells.

Single-channel properties and pH sensitivity of two-pore domain K+ channels of the TALK family

The two-pore K2P channel family comprises TASK, TREK, TWIK, TRESK, TALK, and THIK subfamilies, and TALK-1, TALK-2, and TASK-2 are functional members of the TALK subfamily. Here we report for the first time the single-channel properties of TALK-2 and its pHo sensitivity, and compare them to those of TALK-1 and TASK-2. In transfected COS-7 cells, the three TALK K2P channels could be identified easily by their differences in single-channel conductance and gating kinetics. The single-channel conductances of TALK-1, TALK-2, and TASK-2 in symmetrical 150 mM KCl were 21, 33, and 70 pS (-60 mV), respectively. TALK-2 was sensitive mainly to the alkaline range (pH 7-10), whereas TALK-1 and TASK-2 were sensitive to a wider pHo range (6-10). The effect of pH changes was mainly on the opening frequency. Thus, members of the TALK family expressed in native tissues may be identified based on their single-channel kinetics and pHo sensitivity.

Functional expression of TASK-1/TASK-3 heteromers in cerebellar granule cells

TASK-1 and TASK-3 are functional members of the tandem-pore K+ (K2P) channel family, and mRNAs for both channels are expressed together in many brain regions. Although TASK-1 and TASK-3 subunits are able to form heteromers when their complementary RNAs are injected into oocytes, whether functional heteromers are present in the native tissue is not known. Using cultured cerebellar granule (CG) neurones that express mRNAs of both TASK-1 and TASK-3, we studied the presence of heteromers by comparing the sensitivities of cloned and native K+ channels to extracellular pH (pHo) and ruthenium red. The single-channel conductance of TASK-1, TASK-3 and a tandem construct (TASK-1/TASK-3) expressed in COS-7 cells were 14.2 +/- 0.4, 37.8 +/- 0.7 and 38.1 +/- 0.7 pS (-60 mV), respectively. TASK-3 and TASK-1/TASK-3 (and TASK-3/TASK-1) displayed nearly identical single-channel kinetics. TASK-3 and TASK-1/TASK-3 expressed in COS-7 cells were inhibited by 26 +/- 4 and 36 +/- 2 %, respectively, when pHo was changed from 8.3 to 7.3. In outside-out patches from CG neurones, the K+ channel with single channel properties similar to those of TASK-3 was inhibited by 31 +/- 7 % by the same reduction in pHo. TASK-3 and TASK-1/TASK-3 expressed in COS-7 cells were inhibited by 78 +/- 7 and 3 +/- 4 %, respectively, when 5 microm ruthenium red was applied to outside-out patches. In outside-out patches from CG neurones containing a 38 pS channel, two types of responses to ruthenium red were observed. Ruthenium red inhibited the channel activity by 77 +/- 5 % in 42 % of patches (range: 72-82 %) and by 5 +/- 4 % (range: 0-9 %) in 58 % of patches. When patches contained more than three 38 pS channels, the average response to ruthenium red was 47 +/- 6 % inhibition (n= 5). These electrophysiological studies show that native 38 pS K+ channels of the TASK family in cultured CG neurones consist of both homomeric TASK-3 and heteromeric TASK-1/TASK-3.

Acetylcholine induces Ca 2+ oscillations via m3/m4 muscarinic receptors in the mouse oocyte

Changes in intracellular Ca2+ concentration are required for the activation of mammalian oocytes. They are caused mainly by Ca2+ release from the endoplasmic reticulum (ER) via Ins P3 receptors (Ins P3R). Several studies have reported that acetylcholine (ACh) is capable of triggering early activation events in mouse oocytes over-expressed with the m1 muscarinic ACh receptor (m1AChR). Here we examined which subtypes of the mAChR (m1 to m4) are involved in the generation of Ca2+ oscillations in native mouse oocytes. ACh (10 microM) elicited regular Ca2+ oscillations similar to those induced by sperm in their temporal characteristics. The Ca2+ oscillations were abolished by application with atropine, the mAChR inhibitor. Within 1 min after treatment of ACh, intracellular Fluo-3 fluorescence intensity increased from 794+/-119 to 2023+/-755 (increase to 250% of original value), indicating a strong rise of cytosolic Ca2+ concentration. 4-DAMP mustard and Tropicamide, specific antagonists of m3AChR and m4AChR, completely abolished ACh-induced Ca2+ oscillations. In the ovulated oocytes, the expression of m3/m4 AChR was clearly detected by RT-PCR analysis. Furthermore, ACh-induced Ca2+ oscillations were also abolished or decreased by PLC inhibitors (U73122 or D609) and an Ins P3-receptor antagonist (xestospongin C), confirming that ACh generates Ca2+ oscillations via the PLC-Ins P3 (PI) pathway. These results strongly suggest that m3/m4AChR is coupled to the generation of Ca2+ oscillations mainly via the PI pathway in mouse oocytes.

Functional properties of four splice variants of a human pancreatic tandem-pore K+ channel, TALK-1

TALK-1a, originally isolated from human pancreas, is a member of the tandem-pore K+ channel family. We identified and characterized three novel splice variants of TALK-1 from human pancreas. The cDNAs of TALK-1b, TALK-1c, and TALK-1d encode putative proteins of 294, 322, and 262 amino acids, respectively. TALK-1a and TALK-1b possessed all four transmembrane segments, whereas TALK-1c and TALK-1d lacked the fourth transmembrane domain because of deletion of exon 5. Northern blot analysis showed that among the 15 tissues examined, TALK-1 was expressed mainly in the pancreas. TALK-1a and TALK-1b, but not TALK-1c and TALK-1d, could be functionally expressed in COS-7 cells. Like TALK-1a, TALK-1b was a K+-selective channel that was active at rest. Single-channel openings of TALK-1a and TALK-1b were extremely brief such that the mean open time was <0.2 ms. In symmetrical 150 mM KCl, the apparent single-channel conductances of TALK-1a and TALK-1b were 23 +/- 3 and 21 +/- 2 pS at -60 mV and 11 +/- 2 and 10 +/- 2 pS at +60 mV, respectively. TALK-1b whole cell current was inhibited 31% by 1 mM Ba2+ and 71% by 1 mM quinidine but was not affected by 1 mM tetraethylammonium, 1 mM Cs+, and 100 microM 4-aminopyridine. Similar to TALK-1a, TALK-1b was sensitive to changes in external pH. Acid conditions inhibited and alkaline conditions activated TALK-1a and TALK-1b, with a K1/2 at pH 7.16 and 7.21, respectively. These results indicate that at least two functional TALK-1 variants are present and may serve as background K+ currents in certain cells of the human pancreas.

Properties and modulation of the G protein-coupled K+ channel in rat cerebellar granule neurons: ATP versus phosphatidylinositol 4,5-bisphosphate

Cerebellar granule (CG) neurons express a G protein-gated K+ current (GIRK) that is involved in the neurotransmitter regulation of the excitatory input to the Purkinje fibres of the cerebellum. Here, we characterized the single-channel behaviour of GIRK in CG neurons, and examined the effects of several known modulators of GIRK and their putative physiological roles. Whole-cell GIRKs were activated by baclofen, a GABAB receptor agonist. In cell-attached patches, baclofen activated GIRK with a single-channel conductance of 34 pS and a mean open time of 0.5 ms. In inside-out patches, application of GTPgammaS to the cytoplasmic side activated GIRK with similar kinetic properties. Addition of 2 mM ATP resulted in a marked increase in GIRK activity and induced longer-lived openings with a mean open time of 2.3 ms (ATP-dependent gating). Brain cytosolic fraction or free fatty acids inhibited this effect of ATP, and this was reversed by addition of purified recombinant brain fatty acid binding protein. Applying phosphatidylinositol 4,5-bisphosphate (PIP2) to inside-out patches in place of ATP also increased GIRK activity; however, only an increase in the frequency of opening was observed. The stimulatory effect of PIP2 on GIRK activity was not inhibited by the cytosolic fraction. Following maximal activation by PIP2, ATP caused an additional 2.2-fold increase in GIRK activity. These results show that GIRKs in CG neurons are regulated by positive and negative modulators that affect frequency as well as open time duration. The net effect is that the ligand-activated GIRK is in the 'low activity' state associated with short-lived openings, mainly due to strong action of the cytosolic inhibitor of ATP-dependent gating. Our results also show that intracellular ATP modulates GIRK via pathways different from that of PIP2 in CG neurons.

Genetic polymorphisms of cytochrome P450 19 and 1B1, alcohol use, and breast cancer risk in Korean women

A case-control study was performed to assess the potential influence of CYP19 Arg(264)Cys and CYP1B1 Leu(432)Val polymorphisms on breast cancer risk in a series of Korean breast cancer patients and controls. The results suggest that the CYP19 Arg(264)Cys polymorphism modifies breast cancer risk (OR=1.5, 95% CI=1.1-2.2), especially in association with alcohol consumption (P for interaction=0.04), whereas the CYP1B1 Leu(432)Val polymorphism appears to play no role here.

A protein from the cabbage looper, Trichoplusia ni, regulated by a bacterial infection is homologous to 3-dehydroecdysone 3beta-reductase

During the screening of immune-regulated genes from the cabbage looper, Trichoplusia ni, a 3-dehydroecdysone 3beta-reductase homologue (DERH) was cloned. In the course of development, 3-dehydroecdysone 3beta-reductase mediates the conversion of 3-dehydroecdysone (3dE) secreted from the prothoracic glands to ecdysone (E), which is subsequently converted to 20-hydroxyecdysone (20E), the major insect molting hormone. The cloned gene is upregulated in fat body during development and is strongly induced after the larva is challenged with bacteria. The gene codes for a 308 amino acid residue protein which shows 42.5% identity to Spodoptera littoralis 3-dehydroecdysone 3beta-reductase. Using the baculovirus expression system, the recombinant DERH was expressed. The purified protein mediates the reduction of 3-dehydromakisterone A to makisterone A, and requires NADPH as a cofactor. Western blots using an antiserum to T. ni DERH revealed the presence of the protein in larval hemolymph and integument. The data indicate that the protein is regulated developmentally and is induced after a challenge with bacteria. Immunohistochemical studies localized the enzyme exclusively in the epidermis and the cuticle.

8-oxo-dGTPase, which prevents oxidative stress-induced DNA damage, increases in the mitochondria from failing hearts

BACKGROUND

Reactive oxygen species (ROS) can cause an oxidative modification of nucleotides, such as 8-oxo-7,8-dihydrodeoxyguanosine triphosphate (8-oxo-dGTP), which can lead to defects in DNA replication. The misincorporation of 8-oxo-dGTP into DNA is prevented by 8-oxo-dGTPase, which hydrolyzes 8-oxo-dGTP into 8-oxo-dGMP. The changes in this defensive system have not yet been examined in failing hearts, in which the generation of ROS increases.

METHODS AND RESULTS

Myocardial infarction (MI) was created in mice by ligating the left coronary artery. Four weeks later, the left ventricle was dilated and contractility was diminished on echocardiography. The generation of ROS, as measured by electron spin resonance spectroscopy with 4-hydroxy-2,2,6,6-tetramethyl-piperidine-N-oxyl, increased in the noninfarcted left ventricle from MI mice. The formation of thiobarbituric acid-reactive substances also increased in the mitochondria from MI mice. 8-Oxo-dGTPase was detected in the mitochondrial fractions isolated from MI mice using a Western blot analysis with an antibody to its human homologue (hMTH1). Immunohistochemistry showed positive staining for hMTH1 was localized in the cardiac myocytes.

CONCLUSIONS

The level of 8-oxo-dGTPase increased in the mitochondria isolated from post-MI hearts as oxidative stress increased, thus suggesting that a preventive mechanism is activated against ROS-induced DNA damage. As a result, 8-oxo-dGTPase is considered a useful marker of mitochondrial oxidative stress in heart failure.

Metabolic gene polymorphism frequencies in control populations

Using the International Project on Genetic Susceptibility to Environmental Carcinogens (GSEC) database containing information on over 15,000 control (noncancer) subjects, the allele and genotype frequencies for many of the more commonly studied metabolic genes (CYP1A1, CYP2E1, CYP2D6, GSTM1, GSTT1, NAT2, GSTP, and EPHX) in the human population were determined. Major and significant differences in these frequencies were observed between Caucasians (n = 12,525), Asians (n = 2,136), and Africans and African Americans (n = 996), and some, but much less, heterogeneity was observed within Caucasian populations from different countries. No differences in allele frequencies were seen by age, sex, or type of controls (hospital patients versus population controls). No examples of linkage disequilibrium between the different loci were detected based on comparison of observed and expected frequencies for combinations of specific alleles.

Adeno-associated virus vector-mediated triple gene transfer of dopamine synthetic enzymes

OBJECTIVE

To explore triple gene transfer of dopamine synthetic enzymes with separate adeno-associated virus (AAV) vectors.

METHODS

The genes for dopamine synthetic enzymes, tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC), and GTP cyclohydrolase I (GCH, an enzyme critical for tetrahydrobiopterin synthesis) were contransduced into 293 cells with separate AAV vectors. Expressions of TH, AADC and GCH were detected by Western blot analysis. Intracellular dopamine level was assayed by high-performance liquid chromatography.

RESULTS

TH, AADC and GCH were effectively coexpressed in transduced cells with three separate AAV vectors, AAV-TH, AAV-AADC and AAV-GCH. Furthermore, the coexpression resulted in an effectively spontaneous dopamine production in cotransduced cells.

CONCLUSION

The triple transduction of TH, AADC and GCH genes with separate AAV vectors is effective, which might be important to gene therapy for Parkinson's disease.

Pneumococcal aortic valve endocarditis causing aortopulmonary artery fistula

We report a case of an aortic-pulmonary artery fistula secondary to acute bacterial endocarditis and aortic root abscess formation. The patient presented with generalized symptoms and an initial pneumococcal pneumonia, then developed respiratory and cardiac failure necessitating ventilation and inotropic agents. An echocardiogram showed a vegetation in the aortic valve, an abscess involving the aortic root, and suggested a fistula between the aorta and main pulmonary artery, which was confirmed at emergent operation. Despite a complicated early postoperative course the patient has made a full recovery.

Genomic structure, chromosomal localization and expression profile of a novel melanoma differentiation associated (mda-7) gene with cancer specific growth suppressing and apoptosis inducing properties

Abnormalities in cellular differentiation are frequent occurrences in human cancers. Treatment of human melanoma cells with recombinant fibroblast interferon (IFN-beta) and the protein kinase C activator mezerein (MEZ) results in an irreversible loss in growth potential, suppression of tumorigenic properties and induction of terminal cell differentiation. Subtraction hybridization identified melanoma differentiation associated gene-7 (mda-7), as a gene induced during these physiological changes in human melanoma cells. Ectopic expression of mda-7 by means of a replication defective adenovirus results in growth suppression and induction of apoptosis in a broad spectrum of additional cancers, including melanoma, glioblastoma multiforme, osteosarcoma and carcinomas of the breast, cervix, colon, lung, nasopharynx and prostate. In contrast, no apparent harmful effects occur when mda-7 is expressed in normal epithelial or fibroblast cells. Human clones of mda-7 were isolated and its organization resolved in terms of intron/exon structure and chromosomal localization. Hu-mda-7 encompasses seven exons and six introns and encodes a protein with a predicted size of 23.8 kDa, consisting of 206 amino acids. Hu-mda-7 mRNA is stably expressed in the thymus, spleen and peripheral blood leukocytes. De novo mda-7 mRNA expression is also detected in human melanocytes and expression is inducible in cells of melanocyte/melanoma lineage and in certain normal and cancer cell types following treatment with a combination of IFN-beta plus MEZ. Mda-7 expression is also induced during megakaryocyte differentiation induced in human hematopoietic cells by treatment with TPA (12-O-tetradecanoyl phorbol-13-acetate). In contrast, de novo expression of mda-7 is not detected nor is it inducible by IFN-beta+MEZ in a spectrum of additional normal and cancer cells. No correlation was observed between induction of mda-7 mRNA expression and growth suppression following treatment with IFN-beta+MEZ and induction of endogenous mda-7 mRNA by combination treatment did not result in significant intracellular MDA-7 protein. Radiation hybrid mapping assigned the mda-7 gene to human chromosome 1q, at 1q 32.2 to 1q41, an area containing a cluster of genes associated with the IL-10 family of cytokines. Mda-7 represents a differentiation, growth and apoptosis associated gene with potential utility for the gene-based therapy of diverse human cancers.

Both heavy strand replication origins are active in partially duplicated human mitochondrial DNAs

The replication of human mitochondrial DNA (mtDNA) is initiated from a pair of displaced origins, one priming continuous synthesis of daughter-strand DNA from the heavy strand (OH) and the other priming continuous synthesis from the light strand (OL). In patients with sporadic large-scale rearrangements of mitochondrial DNA (i.e., partially-deleted [Delta-mtDNA] and partially-duplicated [dup-mtDNA] molecules), the dup-mtDNAs typically contain extra origins of replication, but it is unknown at present whether they are competent for initiation of replication. Using cybrids harboring each of two types of dup-mtDNAs-one containing two OHs and two OLs, and one containing two OHs and one OL-we used ligation-mediated polymerase chain reaction (LMPCR) to measure the presence and relative amounts of nascent heavy strands originating from each OH. We found that the nascent heavy strands originated almost equally from the two OHs in each cell line, indicating that the extra OH present on a partially duplicated mtDNA is competent for heavy strand synthesis. This extra OH could potentially confer a replicative advantage to dup-mtDNAs, as these molecules may have twice as many opportunities to initiate replication compared to wild-type (or partially deleted) molecules.

Postmenopausal obesity as a breast cancer risk factor according to estrogen and progesterone receptor status (Japan)

There have been inconsistent results on the association of postmenopausal obesity with breast cancer risk according to the estrogen (ER) and/or progesterone receptor (PR) status in the breast tissue, and this requires further evaluation. This study was designed to assess whether postmenopausal obesity differs according to receptor status. Information on risk factors was obtained from 1154 breast cancer cases and 21714 controls at Aichi Cancer Center Hospital, Nagoya, Japan between 1988 and 1992. The receptor status was known for 40% of cases. Obese postmenopausal women showed an increased risk of breast cancer (odds ratio (OR) for 5 kg of current weight=1.17, 95% confidence interval (CI)=1.10-1.25; OR for 1 kg/m(2) of body mass index (BMI)=1.07, 95% CI=1.04-1.10). The elevated OR was strongest for ER-positive, as well as with PR-positive, breast cancer among postmenopausal women who had a high BMI. The risk did not differ significantly according to ER status. However, obesity indices among postmenopausal women differed with borderline significance according to PR status. These results are consistent with the hypothesis that there is a gradient of risk for postmenopausal obesity according to hormonal receptor status, at least for PR status, although this was not statistically significant.

A Novel Pathway Regulating Lipopolysaccharide-Induced Shock by ST2/T1 Via Inhibition of Toll-Like Receptor 4 Expression

ST2/ST2L, a member of the IL-1R gene family, is expressed by fibroblasts, mast cells, and Th2, but not Th1, cells. It exists in both membrane-bound (ST2L) and soluble forms (ST2). Although ST2L has immunoregulatory properties, its ligand, cellular targets, and mode of action remain unclear. Using a soluble ST2-human IgG fusion protein, we demonstrated that ST2 bound to primary bone marrow-derived macrophages (BMM) and that this binding was enhanced by treatment with LPS. The sST2 treatment of BMMs inhibited production of the LPS-induced proinflammatory cytokines IL-6, IL-12, and TNF-alpha but did not alter IL-10 or NO production. Treatment of BMMs with sST2 down-regulated expression of Toll-like receptors-4 and -1 but induced nuclear translocation of NF-kappaB. Administration of sST2 in vivo after LPS challenge significantly reduced LPS-mediated mortality and serum levels of IL-6, IL-12, and TNF-alpha. Conversely, blockade of endogenous ST2 through administration of anti-ST2 Ab exacerbated the toxic effects of LPS. Thus, ST2 has anti-inflammatory properties that act directly on macrophages. We demonstrate here a novel regulatory pathway for LPS-induced shock via the ST2-Toll-like receptor 4 route. This may be of considerable therapeutic potential for reducing the severity and pathology of inflammatory diseases.

Uteroglobin gene polymorphisms affect the progression of immunoglobulin A nephropathy by modulating the level of uteroglobin expression

Uteroglobin (UG) is an anti-inflammatory/immunomodulatory protein. Targeted disruption of UG rendered mouse glomerulonephritis resembling immunoglobulin (Ig)A nephropathy (IgAN). Sequence analysis on exon 1 of UG showed several putative binding sites for transcription factors, and polymorphisms in this site might influence the expression level of UG as a competitive protein. We speculated that the single nucleotide polymorphism at the 38th nucleotide (A to G) from the transcription initiation site of UG exon 1 would impact the progression of IgA nephropathy (IgAN). Polymerase chain reaction-restriction fragment length polymorphism and single-strand conformation polymorphism were instituted to determine the genetic polymorphism. Luciferase assay was performed using the gene constructs containing a region 404-bp long located upstream of UG exon 1 initiation site to analyse whether this polymorphism would affect the expression level. UG polymorphism was distributed no differently in patients with IgAN (n = 111) compared to 60 healthy control subjects. An excess of A genotype was found in one patient having progressive disease (P = 0.03) and the risk for the disease progression increased as the number of A alleles increased (P for trend = 0.03) after follow-up for 116 months. The odds ratio for progression with the AA genotype was 4.9 (95% Cl = 1.0-23.9) compared to patients having the GG genotype. Significant interactive effects of hypertension and genetic polymorphisms of UG on the disease progression were observed (P for interaction = 0.001). In the luciferase assay, the gene construct with A at the 38th site showed a decreased activity of 74 +/- 8.4% compared to that showed by G gene construct. Our results suggest that polymorphism at the 5' UTR region of UG exon 1 is an important marker for the progression of IgAN and may modulate the level of protein expression.

Feasibility of electron beam tomography in diagnosis of congenital heart disease: comparison with echocardiography

OBJECTIVE

To evaluate the feasibility of electron beam tomography (EBT) for morphological assessment of congenital heart disease.

MATERIALS AND METHODS

Sixteen subjects were examined by EBT, transthoracic echocardiography, cardiac cine angiography and surgery. EBT scan was performed using single slice continuous volume mode to acquire high-resolution static image. Double dose contrast medium was injected by bolus technique after measuring scan delay time and calculation of proper injection rate. The results of EBT and echocardiography were compared based on the results of cardiac cine angiography and surgical findings. All anomalous components were evaluated in all subjects and grouped according to major cardiac structures. Statistical analysis was performed to compare two modalities' ability to evaluate the anomalies of major structures.

RESULTS

EBT was more sensitive to evaluate the anomalies of systemic vessels, pulmonary vessels and small systemic arteries such as coronary artery. EBT was less sensitive to identify the abnormality of cardiac valves such as valvular regurgitation. There was no difference of sensitivity in evaluation of cardiac chambers and septa between the two modalities.

CONCLUSION

EBT assisted by transthoracic echocardiography is excellent noninvasive modality to diagnose congenital heart disease.

Polymorphic catechol-O-methyltransferase gene and breast cancer risk

We examined 483 Finnish breast cancer cases and 482 population controls to determine the potential effect of catechol-O-methyltransferase (COMT) genotype in individual susceptibility to breast cancer. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by unconditional logistic regression after adjustment for known or suspected risk factors for breast cancer. When studied separately by menopausal status, the COMT-L allele-containing genotypes were inversely associated with premenopausal breast cancer, especially with advanced stage of the disease (OR, 0.44; 95% CI, 0.22-0.87). Among postmenopausal women a similar decreased risk was seen for local carcinoma associated with the COMT-LL genotype (OR, 0.55; 95% CI, 0.31-0.98). The lowest breast cancer risk was seen in the postmenopausal women with the COMT-LL genotype and low body-mass index (<or=25.4 kg/m(2); OR, 0.33; 95% CI, 0.13-0.83). Significantly increased risk, on the other hand, was seen for postmenopausal women with the COMT-LL genotype and long-term (>30 months) use of estrogen (OR, 4.02; 95% CI, 1.13-14.3), or with the COMT-L allele-containing genotypes and early age (<or=12 years) at menarche (OR, 8.59; 95% CI, 1.85-39.8). Our study, therefore, suggests that the COMT genotype may define a portion of the individual breast cancer susceptibility that is associated with reproductive events and hormone exposure even if it does not seem to be a major overall risk factor for this malignancy.