Search for Antideuterons of Cosmic Origin Using the BESS-Polar II Magnetic-Rigidity Spectrometer

We searched for antideuterons (d[over ¯]'s) in the 4.7×10^{9} cosmic-ray events observed during the BESS-Polar II flight at solar minimum in 2007-2008 but found no candidates. The resulting 95% C.L. upper limit on the d[over ¯] flux is 6.7×10^{-5}  (m^{2} s sr GeV/n)^{-1} in an energy range from 0.163 to 1.100  GeV/n. The result has improved by more than a factor of 14 from the upper limit of BESS97, which had a potential comparable to that of BESS-Polar II in the search for cosmic-origin d[over ¯]'s and was conducted during the former solar minimum. The upper limit of d[over ¯] flux from BESS-Polar II is the first result achieving the sensitivity to constrain the latest theoretical predictions.

Selective Dissolution-Derived Nanoporous Design of Impurity-Free Bi2 Te3 Alloys with High Thermoelectric Performance

Thermoelectric technology, which has been receiving attention as a sustainable energy source, has limited applications because of its relatively low conversion efficiency. To broaden their application scope, thermoelectric materials require a high dimensionless figure of merit (ZT). Porous structuring of a thermoelectric material is a promising approach to enhance ZT by reducing its thermal conductivity. However, nanopores do not form in thermoelectric materials in a straightforward manner; impurities are also likely to be present in thermoelectric materials. Here, a simple but effective way to synthesize impurity-free nanoporous Bi_0.4 Sb_1.6 Te₃ via the use of nanoporous raw powder, which is scalably formed by the selective dissolution of KCl after collision between Bi_0.4 Sb_1.6 Te₃ and KCl powders, is proposed. This approach creates abundant nanopores, which effectively scatter phonons, thereby reducing the lattice thermal conductivity by 33% from 0.55 to 0.37 W m^-1 K^-1 . Benefitting from the optimized porous structure, porous Bi_0.4 Sb_1.6 Te₃ achieves a high ZT of 1.41 in the temperature range of 333-373 K, and an excellent average ZT of 1.34 over a wide temperature range of 298-473 K. This study provides a facile and scalable method for developing high thermoelectric performance Bi₂ Te₃ -based alloys that can be further applied to other thermoelectric materials.

Precision Interface Engineering of an Atomic Layer in Bulk Bi2Te3 Alloys for High Thermoelectric Performance

Grafting nanotechnology on thermoelectric materials leads to significant advances in their performance. Creation of structural defects including nano-inclusion and interfaces via nanostructuring achieves higher thermoelectric efficiencies. However, it is still challenging to optimize the nanostructure via conventional fabrication techniques. The thermal instability of nanostructures remains an issue in the reproducibility of fabrication processes and long-term stability during operation. This work presents a versatile strategy to create numerous interfaces in a thermoelectric material via an atomic-layer deposition (ALD) technique. An extremely thin ZnO layer was conformally formed via ALD over the Bi_0.4Sb_1.6Te₃ powders, and numerous heterogeneous interfaces were generated from the formation of Bi_0.4Sb_1.6Te₃-ZnO core-shell structures even after high-temperature sintering. The incorporation of ALD-grown ZnO into the Bi_0.4Sb_1.6Te₃ matrix blocks phonon propagation and also provides tunability in electronic carrier density via impurity doping at the heterogeneous grain boundaries. The exquisite control in the ALD cycles provides a high thermoelectric performance of zT = 1.50 ± 0.15 (at 329-360 K). Specifically, ALD is an industry compatible technique that allows uniform and conformal coating over large quantities of powders. The study is promising in terms of the mass production of nanostructured thermoelectric materials with considerable improvements in performance via an industry compatible and reproducible route.

Observations of the Interaction and Transport of Fine Mode Aerosols with Cloud and/or Fog in Northeast Asia from Aerosol Robotic Network (AERONET) and Satellite Remote Sensing

Analysis of sun photometer measured and satellite retrieved aerosol optical depth (AOD) data has shown that major aerosol pollution events with very high fine mode AOD (>1.0 in mid-visible) in the China/Korea/Japan region are often observed to be associated with significant cloud cover. This makes remote sensing of these events difficult even for high temporal resolution sun photometer measurements. Possible physical mechanisms for these events that have high AOD include a combination of aerosol humidification, cloud processing, and meteorological co-variation with atmospheric stability and convergence. The new development of Aerosol Robotic network (AERONET) Version 3 Level 2 AOD with improved cloud screening algorithms now allow for unprecedented ability to monitor these extreme fine mode pollution events. Further, the Spectral Deconvolution Algorithm (SDA) applied to Level 1 data (L1; no cloud screening) provides an even more comprehensive assessment of fine mode AOD than L2 in current and previous data versions. Studying the 2012 winter-summer period, comparisons of AERONET L1 SDA daily average fine mode AOD data showed that Moderate Resolution Imaging Spectroradiometer (MODIS) satellite remote sensing of AOD often did not retrieve and/or identify some of the highest fine mode AOD events in this region. Also, compared to models that include data assimilation of satellite retrieved AOD, the L1 SDA fine mode AOD was significantly higher in magnitude, particularly for the highest AOD events that were often associated with significant cloudiness.

Free-electron creation at the 60° twin boundary in Bi2Te3

Interfaces, such as grain boundaries in a solid material, are excellent regions to explore novel properties that emerge as the result of local symmetry-breaking. For instance, at the interface of a layered-chalcogenide material, the potential reconfiguration of the atoms at the boundaries can lead to a significant modification of the electronic properties because of their complex atomic bonding structure. Here, we report the experimental observation of an electron source at 60° twin boundaries in Bi₂Te₃, a representative layered-chalcogenide material. First-principles calculations reveal that the modification of the interatomic distance at the 60° twin boundary to accommodate structural misfits can alter the electronic structure of Bi₂Te₃. The change in the electronic structure generates occupied states within the original bandgap in a favourable condition to create carriers and enlarges the density-of-states near the conduction band minimum. The present work provides insight into the various transport behaviours of thermoelectrics and topological insulators.

Grain boundaries in polycrystalline materials may offer the opportunity to explore physical phenomena that do not normally occur within the crystal grains. Here, the authors show that twin boundaries in Bi₂Te₃ works as an electron supply for the whole bulk material.

High mobility, large linear magnetoresistance, and quantum transport phenomena in Bi2Te3 films grown by metallo-organic chemical vapor deposition (MOCVD)

We investigated the magnetotransport properties of Bi2Te3 films grown on GaAs (001) substrate by a cost-effective metallo-organic chemical vapor deposition (MOCVD). We observed the remarkably high carrier mobility and the giant linear magnetoresistance (carrier mobility ∼ 22 000 cm(2) V(-1) s(-1), magnetoresistance ∼ 750% at 1.8 K and 9 T for a 100 nm thick film) that depends on the film thickness. In addition, the Shubnikov-de Haas oscillation was observed, from which the effective mass was calculated to be consistent with the known value. From the thickness dependence of the Shubnikov-de Haas oscillation, it was found that a two dimensional electron gas with the conventional electron nature coexists with the topological Dirac fermion states and dominates the carrier transport in the Bi2Te3 film with thickness higher than 300 nm. These results are attributed to the intrinsic nature of Bi2Te3 in the high-mobility transport regime obtained by a deliberate choice of the substrate and the growth conditions.

Extensive curettage using a high-speed burr versus dehydrated alcohol instillation for the treatment of enchondroma of the hand

The purpose of this retrospective study was to compare the clinical and radiological outcomes of patients treated with different adjuvant methods after curettage for enchondromas of the hand. Sixty-two patients with enchondroma were treated with high-speed burring (29 patients) or alcohol instillation (33 patients) after curettage. The mean follow-up was 40.8 months. No significant differences in the visual analogue scale, Disabilities of the Arm, Shoulder, and Hand scores, total range of active motion, grip strength, and complete healing time were observed between the groups. The distribution of the results of the formula by Wilhelm and Feldmeier were not significantly different between the groups. No surgery-related complications, postoperative pathological fractures, or recurrence was found in either group. For the treatment of enchondroma in the metacarpal and proximal phalanx, alcohol instillation immediately after curettage was as effective as extensive curettage using a high-speed burr.

Association between shortened cervical length at 34-36 weeks' gestation and term labour in Asian women

Cervical length was measured at 34-36 weeks' gestation by transvaginal ultrasound. The purpose of measurement of cervical length before term was to reveal the association with the onset of term labour. This was a retrospective study of 362 women who were delivered at term at Mizmedi hospital, between August 2006 and November 2011. There was significant linear correlation between cervical length and the scan-to-labour interval in women with labour before 41 weeks. The measurement of cervical length at 34-36 weeks' gestation might be helpful in predicting the onset of term labour before 41 weeks.

Suitability of endoscopic submucosal dissection for treatment of submucosal gastric cancers

BACKGROUND

Endoscopic submucosal dissection (ESD) is not considered appropriate for all submucosal cancers owing to the risk of lymph node metastasis and difficulty estimating the deep margin status. This study aimed to determine predictive factors for lymph node metastases in submucosal cancer and to explore in which patients ESD might be feasible.

METHODS

Details of patients who had curative gastrectomy for submucosal gastric cancer at Asan Medical Centre from 2007 to 2011 were reviewed retrospectively to determine the relationship between lymph node metastasis and clinicopathological characteristics, including age, sex, tumour location, size, gross appearance, depth of invasion, histological type/differentiation, presence of lymphovascular/perineural invasion, and immunohistochemical staining results for p53, human epidermal growth factor receptor (HER) 1 and HER2.

RESULTS

A total of 1773 patients were analysed. The presence of lymphovascular invasion was related most strongly to lymph node metastasis. Multivariable analysis revealed that depth of invasion, tumour size, differentiation, gross appearance and perineural invasion were also related. Metastatic lymph nodes were found in four of 105 patients who met the classical criteria for ESD; all showed a moderately differentiated histological appearance. No lymph node metastases were observed in well differentiated SM1 tumours of any size (infiltration into upper third of submucosa), or in well differentiated SM2 (infiltration into middle third of submucosa) tumours of 2 cm or less without lymphovascular invasion.

CONCLUSION

Patients with well differentiated SM1 cancer of any size and those with well differentiated SM2 cancer of 2 cm or less without lymphovascular invasion may be suitable candidates for ESD.

Thermoelectric properties of Bi2Te3-In2Se3 composite thin films prepared by co-sputtering

Bi2Te3-In2Se3 films were prepared by co-sputtering followed by annealing, and their structural and thermoelectric properties were investigated. The immiscible nature of the two alloys results in precipitation of the second phase, thus leading to structures with self-assembled dots that are a few nanometers in scale. HAADF-STEM and HRTEM were used to confirm that In2Se3 nanodots that were a few nanometers in size did indeed form in the Bi2Te3 thin film. It was found that the incorporation of these nanodots can reduce the thermal conductivity of the thin film.

Growth and thermoelectric properties of multilayer thin film of bismuth telluride and indium selenide via rf magnetron sputtering

A bismuth telluride (BT)/indium selenide (IS) multilayer film was deposited at room temperature by rf magnetron sputtering on a sapphire substrate in order to investigate how the multilayered structure affects the microstructure and thermoelectric properties. The effect of annealing at different temperatures was also studied. The results were compared with those from a BT film with the same thickness. A TEM study showed that the interface between the BT and IS layers became vague as the annealing temperature increased, and the BT layer crystallized while the IS layer did not. The presence of thin IS layers can help to limit the evaporation of Te from the BT/IS multilayer film, thus increasing the amount of Bi2Te3 phase in the multilayer film as compared with that of the BT film. An abrupt increase in the Seebeck coefficient of the multilayer film was observed when annealed at 300 degrees C, and the resistivity of the annealed multilayer film was high compared to that of the BT film. This result can also be explained by the proposed role of the IS layer, which limits the evaporation of Te at high temperature. The highest power factor of -3.9 x 10(-6) W/K2 cm was obtained at room temperature from the multilayer film annealed at 300 degrees C.

Search for antihelium with the BESS-Polar spectrometer

In two long-duration balloon flights over Antarctica, the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) collaboration has searched for antihelium in the cosmic radiation with the highest sensitivity reported. BESS-Polar I flew in 2004, observing for 8.5 days. BESS-Polar II flew in 2007-2008, observing for 24.5 days. No antihelium candidate was found in BESS-Polar I data among 8.4×10(6) |Z|=2 nuclei from 1.0 to 20 GV or in BESS-Polar II data among 4.0×10(7) |Z|=2 nuclei from 1.0 to 14 GV. Assuming antihelium to have the same spectral shape as helium, a 95% confidence upper limit to the possible abundance of antihelium relative to helium of 6.9×10(-8)} was determined combining all BESS data, including the two BESS-Polar flights. With no assumed antihelium spectrum and a weighted average of the lowest antihelium efficiencies for each flight, an upper limit of 1.0×10(-7) from 1.6 to 14 GV was determined for the combined BESS-Polar data. Under both antihelium spectral assumptions, these are the lowest limits obtained to date.

Measurement of the cosmic-ray antiproton spectrum at solar minimum with a long-duration balloon flight over antarctica

The energy spectrum of cosmic-ray antiprotons (p's) from 0.17 to 3.5 GeV has been measured using 7886 p's detected by BESS-Polar II during a long-duration flight over Antarctica near solar minimum in December 2007 and January 2008. This shows good consistency with secondary p calculations. Cosmologically primary p's have been investigated by comparing measured and calculated p spectra. BESS-Polar II data show no evidence of primary p's from the evaporation of primordial black holes.

MtDNA haplogroups and elite Korean athlete status

Mitochondrial DNA (mtDNA) variation has recently been suggested to have an association with athletic performance or physical endurance. Since mtDNA is haploid and lacks recombination, specific mutations in the mtDNA genome associated with human exercise tolerance or intolerance arise and remain in particular genetic backgrounds referred to as haplogroups. To assess the possible contribution of mtDNA haplogroup-specific variants to differences in elite athletic performance, we performed a population-based study of 152 Korean elite athletes [77 sprint/power athletes (SPA) and 75 endurance/middle-power athletes (EMA)] and 265 non-athletic controls (CON). The overall haplogroup distribution of EMA differed significantly from CON (p<0.01), but that of SPA did not. The EMA have an excess of haplogroups M* (OR 4.38, 95% CI 1.63-11.79, p=0.003) and N9 (OR 2.32, 95% CI 0.92-5.81, p=0.042), but a dearth of haplogroup B (OR 0.26, 95% CI 0.09-0.75, p=0.003) compared with the CON. Thus, our data imply that specific mtDNA lineages may provide a significant effect on elite Korean endurance status, although functional studies with larger sample sizes are necessary to further substantiate these findings.

Time-resolved measurements of PM2.5 carbonaceous aerosols at Gosan, Korea

In order to better understand the characteristics of atmospheric carbonaceous aerosol at a background site in Northeast Asia, semicontinuous organic carbon (OC) and elemental carbon (EC), and time-resolved water-soluble organic carbon (WSOC) were measured by a Sunset OC/ EC and a PILS-TOC (particle-into-liquid sampler coupled with an online total organic carbon) analyzer, respectively, at the Gosan supersite on Jeju Island, Korea, in the summer (May 28-June 17) and fall (August 24-September 30) of 2009. Hourly average OC concentration varied in the range of approximately 0.87-28.38 microgC m-3, with a mean of 4.07+/- 2.60 microgC m-3, while the hourly average EC concentration ranged approximately from 0.04 to 8.19 .microgC m-3, with a mean of 1.35 +/- 0.71 microgC m-3, from May 28 to June 17, 2009. During the fall season, OC varied in the approximate range 0.9-9.6 microgC m-3, with a mean of 2.30 +/-0.80 microgC m-3, whereas EC ranged approximately from 0.01 to 5.40 microgC m-3, with a mean of 0.66 +/- 0.38 microgC m-3. Average contributions of EC to TC and WSOC to OC were 26.0% +/- 9.7% and 20.6% +/-7.4%, and 37.6% +/- 23.5% and 57.2% +/- 22.2% during summer and fall seasons, respectively. As expected, clear diurnal variation of WSOC/OC was found in summer, varying from 0.22 during the nighttime up to 0.72 during the daytime, mainly due to the photo-oxidation process. In order to investigate the effect of air mass pathway on the characteristics of carbonaceous aerosol, 5-day back-trajectory analysis was conducted using the HYSPLIT model. The air mass pathways were classified into four types: Continental (CC), Marine (M), East Sea (ES) and Korean Peninsula (KP). The highest OC/EC ratio of 3.63 was observed when air mass originated from the Continental area (CC). The lowest OC/EC ratio of 0.79 was measured when air mass originated from the Marine area (M). A high OC concentration was occasionally observed at Gosan due to local biomass burning activities. The contribution of secondary OC to total OC varied approximately between 8.4% and 32.2% and depended on air mass type.

Acute respiratory distress syndrome caused by miliary tuberculosis: a multicentre survey in South Korea

BACKGROUND

Miliary tuberculosis (TB) is an unusual cause of acute respiratory distress syndrome (ARDS).

OBJECTIVE

To evaluate the clinical characteristics and outcomes of patients with ARDS caused by miliary TB admitted to the intensive care unit (ICU).

DESIGN

A total of 67 patients were enrolled during the period 1999-2008.

RESULTS

The median age of the patients was 56 years (range 17-81), 19 (28.4%) were aged >71 years, and 38 (56.7%) were male. All-cause mortality in the ICU and hospital were respectively 58.2% and 61.2%. Of the total number of enrolled patients, 49 (73.1%) were prescribed anti-tuberculosis medication within 3 days of hospital admission. On the day of ARDS diagnosis (10.0 ± 3.7 vs. 7.4 ± 3.5, P = 0.005), non-survivors had a significantly higher Sequential Organ Failure Assessment (SOFA) score than survivors. Multivariate analysis showed that SOFA score on the day of ARDS diagnosis was a significant predictor of survival (OR 0.809, 95%CI 0.691-0.946, P = 0.008). It was difficult to determine the efficacy of systemic corticosteroids on patient survival.

CONCLUSION

ARDS caused by miliary TB was associated with a high in-hospital mortality rate, with SOFA score on the day of ARDS diagnosis being a valuable prognostic indicator.

Incomplete discoid glenoid labrum combined with a ganglion cyst of the spinoglenoid notch

In a 41-year-old man, right-sided infraspinatus muscle weakness was associated with compression of the suprascapular nerve caused by a spinoglenoid ganglion cyst. The lesion was confirmed using electromyography and MRI. In addition, arthroscopy showed an incomplete discoid labrum. The free inner edge of the labrum was removed as in a meniscectomy of a discoid meniscus in the knee joint. Arthroscopic decompression of the cyst was performed through a juxtaglenoid capsulotomy which was left open. Neurological function recovered completely.

Salvage of the lower extremity free flap using cross-leg venous repair

This retrospective study was designed to evaluate a salvage technique for free flaps suffering venous congestion by using a cross-leg vein repair in patients with venous-impaired lower extremities. Four free flap reconstructions were performed using the latissimus dorsi muscle to reconstruct soft tissue defects in the lower extremity. The recipient artery was confined to the ipsilateral leg and the venous anastomosis was performed with a long saphenous vein from the contralateral side. The legs were immobilised together by means of an external fixator. All patients were males with a mean age of 31 years. The mean time of pedicle division was 8.8 days (7-10). The mean size of the free flap was 186.5 cm(2). All flaps survived after pedicle division without venous congestion. There were no complications such as joint stiffness or donor site morbidity except for a linear scar. The cross-leg venous repair is a refinement of a salvage procedure for compromised free flaps used in the reconstruction of severe soft tissue defects in vascularly compromised lower extremities.

MUC1 cytoplasmic tail detection using CT33 polyclonal and CT2 monoclonal antibodies in breast and colorectal tissue

The immunohistochemical detection (IHC) of MUC1-CT employing a polyclonal antibody (CT33) in relation to CT2 monoclonal antibody (MAb) was analyzed. Western blot (WB) was used to determine the molecular mass of CT.

MATERIALS AND METHODS

We studied 163 breast and 89 colorectal cancer specimens, 10 breast and 14 colorectal benign conditions, and 12 breast and 20 colorectal normal samples. From each tumor sample, subcellular fractions were obtained and analyzed by SDS-PAGE and WB. A nonparametric statistical analysis was employed; data were standardized and a Kendall-Tau correlation was applied.

RESULTS

By IHC, 146/163 (90%) and 151/163 (93%) of breast cancer were positive with CT33 and CT2, respectively; a statistically significant correlation was obtained (t=0.5199). Seven out of ten (70%) benign breast specimens were positive with CT33 while all samples stained with CT2; in normal breast sample tissues, all were positive with both Abs. In colorectal cancer samples, both antibodies stained 47/89 (53%) samples; CT2 reacted in 13/14 (93%) of benign samples while CT33 showed a positive reaction in 9/14 (64%) of benign specimens. In normal samples, CT2 showed staining in 17/20 (85%) of samples and CT33 was reactive in 12/20 (60%). By WB, in breast and colorectal cancer samples, similar results were obtained with both antibodies: a main band at about 30kDa which represents the smaller subunit.

CONCLUSION

CT33 polyclonal antibody has demonstrated its efficacy to detect MUC1 in breast and colorectal cancer tissues with similar reactivity to CT2. It is worthwhile to affirm that CT33 is a good indicator of MUC1 expression.

9p subtelomere deletion: pathogenic mutation or normal variant?

We report an apparently benign familial 9p subtelomere deletion identified using chromosome-arm-specific subtelomere probes in a patient with multiple congenital anomalies. Our experience demonstrated that the discovery of a subtelomeric deletion and/or duplication does not always guarantee the identification of the etiology for the patients phenotype and a positive finding with subtelomere probes should always be followed by parental study with the same probe in order to distinguish a disease causing alteration from a benign familial polymorphism.

Disruption of DMD and deletion of ACSL4 causing developmental delay, hypotonia, and multiple congenital anomalies

We have studied a male patient with significant developmental delay, growth failure, hypotonia, girdle weakness, microcephaly, and multiple congenital anomalies including atrial (ASD) and ventricular (VSD) septal defects. Detailed cytogenetic and molecular analyses revealed three de novo X chromosome aberrations and a karyotype 46,Y,der(X)inv(X) (p11.4q11.2)inv(X)(q11.2q21.32 approximately q22.2)del(X)(q22.3q22.3) was determined. The three X chromosome aberrations in the patient include: a pericentric inversion (inv 1) that disrupted the Duchenne muscular dystrophy (DMD) gene, dystrophin, at Xp11.4; an Xq11.2q21.32 approximately q22.2 paracentric inversion (inv 2) putatively affecting no genes; and an interstitial deletion at Xq22.3 that results in functional nullisomy of several known genes, including a gene previously associated with X-linked nonsyndromic mental retardation, acyl-CoA synthetase long chain family member 4 (ACSL4). These findings suggest that the disruption of DMD and the absence of ACSL4 in the patient are responsible for neuromuscular disease and cognitive impairment.

Effects of activation of polymorphonuclear leukocytes on airway goblet cell mucin release in a co-culture system

OBJECTIVE AND DESIGN

Effects of activated PMN on airway goblet cell mucin release were investigated using a co-culture system in which both tracheal surface epithelial (TSE) cells and PMN from hamsters were present.

MATERIALS AND METHODS

TSE cells were metabolically labeled using (3)H-glucosamine and chased in the presence of PMN under various experimental designs. PMN were obtained from the bronchoalveolar lavage fluid of hamsters following intratracheal instillation of E. coli endotoxin. The amount of (3)H-mucin was measured by Sepharose CL-4B gel-filtration column chromatography.

RESULTS

(i). activation of 10(6) PMN by fMLP (0.1 microM) and cytochalasin B (0.1 microM) resulted in production of both the estrolytic ("elastolytic") activity and superoxide, (ii). activation of PMN in the co-culture stimulated mucin release from TSE cells followed by a significant degradation of the released mucins, both of which were blocked in a dose-dependent fashion by pretreatment with alpha1-protease inhibitor, and (iii). generation of varying concentrations of superoxide in the TSE cell culture did not affect mucin release from TSE cells.

CONCLUSION

In the co-culture system, activation of PMN results in release and degradation of mucins, both of which are almost entirely accounted for by serine proteases but not other cellular products such as superoxide.

Imatinib (ST1571) provides only limited selectivity for CML cells and treatment might be complicated by silent BCR-ABL genes

Very promising results have been obtained in clinical trials on chronic-phase chronic myeloid leukemia (CP-CML) patients treated with imatinib mesylate (IM; Gleevecr, STI571), a BCR-ABL tyrosine kinase inhibitor. However, we found that IM caused considerable inhibition of normal hematopoietic progenitor cells upon treating control bone marrow (BM) cultures. In vitro IM treatment gave a decrease in the yield and size of colonies from BM of untreated CP-CML patients that was only two to three times that from the normal samples. Moreover, about 30% of myeloid progenitors (CFU-GM) from CML BM still formed colonies in the presence of IM, most of which had BCR-ABL RNA. About half of these treated colonies also displayed methylation of the internal ABL Pa promoter, a CML-specific epigenetic alteration, which was used in this study as a marker for BCR-ABL translocation-containing cells. However, ~5-8% of the treated or the untreated CML BM-derived colonies had no detectable BCR-ABL RNA by two or three rounds of RT-PCR despite being positive for the internal standard RNA and displaying hallmarks of CML, either t(9;22)(q34;ql 1) or ABL Pa methylation. Our results indicate that IM is only partially specific for CML progenitor cells compared to normal hematopoietic progenitor cells and suggest that some CML cells may have a silent BCR-ABL oncogene that could interfere with therapy.

Intra-group differences in business participation: three Asian immigrant groups

This study investigates ethnic and nativity differentials in self-employment based on the small-business experiences of 3 Asian immigrant groups in the US: Korean, Chinese, and Asian Indians. In light of the 1980 Census data, the intra- and the inter-group differences in the business participation rates of these Asian immigrant groups are examined. Findings reveal that each group has substantial intra-group differences in the business participation rate, and the differences can best be explained by the interactive approach proposed by this study. Moreover, a comparative study (inter-group comparison) of these intra-group differences opens a new avenue to understanding the various patterns of business participation among recent immigrants from Asia.

Effects of polycationic peptides on mucin release from airway goblet cells: relationship between polymer size and activity

OBJECTIVES AND DESIGN

Various sizes of poly-L-lysine (PLL) and poly-L-arginine (PLA) were tested for their possible effects on airway goblet cell mucin release using primary hamster tracheal surface epithelial (HTSE) cells in an attempt to identify the smallest size of the polycationic peptide to suppress mucin release without cytotoxicity.

MATERIALS AND METHODS

HTSE cells were metabolically labeled using 3H-glucosamine and chased in the presence of varying concentrations of various sizes of the polycationic peptides. The amount of 3H-mucin in the spent media was measured by Sepharose CL-4B gel-filtration column chromatography. Possible cytotoxicity of the peptides was assessed by measuring the release of lactic dehydrogenase (LDH) during the treatment period.

RESULTS

(1) PLL (MW 78,000) inhibited whereas PLA (MW 92,000) stimulated mucin release. However, these peptides were cytotoxic at the effective concentrations; (2) Both PLL (MW 9,600) and PLA (MW 8,900) could inhibit mucin release in a dose dependent manner without cytotoxicity; (3) Both PLL and PLA were effective in suppressing mucin release in 20-mer but not in either 10-mer or 5-mer; (4) 14-mers of both PLL and PLA also inhibited mucin release without cytotoxicity; (5) PLL and poly-D-lysine (PDL) of 14-mer were equipotent in its ability to suppress mucin release.

CONCLUSION

Both PLL and PLA are cytotoxic at 'high' molecular weights, but have an ability to suppress mucin release without cytotoxicity at 'low' molecular weights. 14-mer seems to be the small, effective size, if not the smallest, for both PLL and PLA to suppress mucin release without cytotoxicity. The inhibitory effect of these polycationic peptides seems to be determined by the presence and the absolute number of positive charges and also to be independent of optical isomerism.

Amphiphysin IIb-1, a novel splicing variant of amphiphysin II, regulates p73beta function through protein-protein interactions

p73 is a nuclear protein that is similar in structure and function to p53. Notably, the C-terminal region of p73 has a regulatory function, through interactions with a positive or negative regulator. In this study, we use the yeast two-hybrid technique to identify a novel p73beta binding protein, designated amphiphysin IIb-1. Amphiphysin IIb-1 is one of the splicing variants of amphiphysin II, and has a shorter protein product than amphiphysin IIb, which has been previously reported. We confirmed that amphiphysin IIb-1 binds full-length p73beta, both in vitro and in vivo. This association is mediated via the SH3 domain of amphiphysin IIb-1 and C-terminal amino acids 321-376 of p73beta. Double immunofluorescence patterns revealed that p73beta is relocalized to the cytoplasm in the presence of amphiphysin IIb-1. Overexpression of amphiphysin IIb-1 was found to significantly inhibit the transcriptional activity of p73beta in a dose-dependent manner. In addition, the cell death function of p73beta was inhibited by amphiphysin IIb-1. These findings offer a new insight into the regulation mechanism of p73beta, and suggest that amphiphysin IIb-1 modulates p73beta function by direct binding.

Induction of apoptosis in p53-deficient human hepatoma cell line by wild-type p53 gene transduction: inhibition by antioxidant

We investigated the role of wild-type (wt)-p53 as an inducer of apoptotic cell death in human hepatoma cell lines. Following the retrovirus-mediated transduction of the wt-p53 gene, Hep3B cells lacking the endogenous p53 expression began to die through apoptosis in 4 h. They showed a maximal apoptotic death at 12 h, whereas HepG2 cells expressing endogenous p53 did not. However, the transduction of the wt-p53 gene elicited growth suppression of both Hep3B and HepG2 cells. P21(WAF1/CIP1), a p53-inducible cell cycle inhibitor, was induced, not only in Hep3B cells undergoing apoptosis, but also in HepG2 cells. The kinetics of the p21(WAF1/CIP1) induction, DNA fragmentation, and growth suppression of the Hep3B cells showed that DNA fragmentation and growth suppression progressed rapidly following p21(WAF1/CIP1) accumulation. N-acetyl-cysteine or glutathione, potent antioxidants, strongly inhibited the DNA fragmentation, but did not reduce the elevated level of p21(WAF1/CIP1). These findings suggested that p21(WAF1/CIP1) was not a critical mediator for the execution of p53-mediated apoptosis, although it contributed to the growth inhibition of cells undergoing apoptosis. Furthermore, p53-mediated apoptosis could be repressed by antioxidants.

Reciprocal expressions of cyclin E and cyclin D1 in hepatocellular carcinoma

Deregulation of the cell cycle by overexpression of G1 cyclins, cyclin E and cyclin D1 genes, has been demonstrated to be a prerequisite for the development of human cancer. Recently, cyclin E is proposed to be sufficient for the progression of the G1 cell cycle without cyclin D1. Here we show that the proposed model system was specifically present in human hepatocellular carcinoma (HCC) unlike other human cancers. Of 31 HCC tissues analyzed, 21 (67.7%) exhibited an overexpression of cyclin E protein. In contrast to cyclin E gene expression, cyclin D1 expression was strongly downregulated in 19 (61.2%) HCCs. Interestingly, 65% of HCC tissues with overexpression of the cyclin E gene exhibited downregulation of cyclin D1, suggesting reciprocal deregulation of these cyclins in the G1 progression of the cell cycle. Southern blot analysis proved the amplification of cyclin E gene in HCC with a high level of overexpression. The present findings suggest that the reciprocal deregulation of cyclin E lacking cyclin D1 expression might play a role in G1 progression and the development of HCC.

Involvement of the MAP kinase ERK2 in MUC1 mucin signaling

MUC1 mucin is a receptor-like glycoprotein expressed abundantly in various cancer cell lines as well as in glandular secretory epithelial cells, including airway surface epithelial cells. The role of this cell surface mucin in the airway is not known. In an attempt to understand the signaling mechanism of MUC1 mucin, we established a stable cell line from COS-7 cells expressing a chimeric receptor consisting of the extracellular and transmembrane domains of CD8 and the cytoplasmic (CT) domain of MUC1 mucin (CD8/MUC1 cells). We previously observed that treatment of these cells with anti-CD8 antibody resulted in tyrosine phosphorylation of the CT domain of the chimera. Here we report that treatment of CD8/MUC1 cells with anti-CD8 resulted in activation of extracellular signal-regulated kinase (ERK) 2 as assessed by immunoblotting, kinase assay, and immunocytochemistry. The activation of ERK2 was completely blocked either by a dominant negative Ras mutant or in the presence of a mitogen-activated protein kinase kinase (MEK) inhibitor. We conclude that tyrosine phosphorylation of the CT domain of MUC1 mucin leads to activation of a mitogen-activated protein kinase pathway through the Ras-MEK-ERK2 pathway. Combined with the existing data by others, it is suggested that one of the roles of MUC1 mucin may be regulation of cell growth and differentiation via a common signaling pathway, namely the Grb2-Sos-Ras-MEK-ERK2 pathway.