Organization of the human transferrin gene: direct evidence that it originated by gene duplication.

We present the characterization of two overlapping human transferrin genomic clones isolated from a liver DNA library. The two clones represent a total length of 24 kilobase pairs and code for 70% of the protein. The organization of this gene region was elucidated by restriction mapping and DNA sequencing. It contains 12 exons, ranging from 33 to 181 base pairs, separated by introns of 0.7-4.9 kilobase pairs. This gene can be divided into two unequal parts corresponding to the known domains of the protein. Each part is essentially composed of an equal number of exons; introns interrupt the coding sequences, creating homologous exons of similar size in each moiety. Moreover, the pattern of intron interruption of the codon sequence is identical for all the analyzed homologous exon pairs. Comparison with the organization of the ovotransferrin gene shows an identical exon size distribution. These data confirm, at the gene level, the hypothesis that transferrins originated by a gene-duplication event. A model accounting for the origin of the human transferrin gene is presented.     

General 2.5 power law of metallic glasses

Metallic glass (MG) is an important new category of materials, but very few rigorous laws are currently known for defining its “disordered” structure. Recently we found that under compression, the volume (V) of an MG changes precisely to the 2.5 power of its principal diffraction peak position (1/q₁). In the present study, we find that this 2.5 power law holds even through the first-order polyamorphic transition of a Ce₆₈Al₁₀Cu₂₀Co₂ MG. This transition is, in effect, the equivalent of a continuous “composition” change of 4f-localized “big Ce” to 4f-itinerant “small Ce,” indicating the 2.5 power law is general for tuning with composition. The exactness and universality imply that the 2.5 power law may be a general rule defining the structure of MGs.Metallic glasses (MGs) possess many unique and superior properties, such as extremely high strength, hardness, and corrosion resistance, etc., making them promising metallic materials with widespread applications (1, 2). Thousands of MGs with a wide range of compositions and properties have been synthesized over the past decades. However, so far the development of MGs is mainly based on tedious composition mapping in multicomponent space to pinpoint the combination of elements with optimized glass-forming ability (GFA). This method for development of MGs is a time- and resource-intensive strategy of trial and error which highlights the need for the guidance of a general theory (2, 3). Intensive research effort has been devoted to finding general rules in various MGs to understand the fundamentals and to guide the development of new MGs (4, 5). Quantitative correlations between their properties have been observed. For instance, compressive yield strength and elastic moduli of MGs are found to be intimately connected with their glass transition temperature T_g (6–10), and the ductility, fragility (11, 12), and Poisson’s ratio of MGs are closely related (13–16). The extensive correlations in properties suggest that the disordered MGs may share general rules in their structure. To clarify this scenario, detailed and accurate structural information spanning short range to long range is required. However, the current experimental probes and theories are limited to local structure in MGs (17). Therefore, understanding how the atoms efficiently fill up the 3D space and how this controls the bulk properties of MGs remains a long-standing theoretical challenge (18–23). To date, few general and exact rules regarding structure–property relationships have been established in MGs (23).Encouraging progress on understanding structure–property relationships in MGs has recently been made through the discoveries of the noncubic (2.3 or 2.5) power laws that correlate the principal diffraction peak (PDP) position q₁ with the bulk density ρ or average atomic volume, V_a, i.e., ρ∝(q₁)^D or V_a∝(1/q₁)^D, where D equals ∼2.3 with varying the composition of MGs at ambient pressure (19) or ∼2.5 for tuning the density of MGs with pressure (22, 24). Whereas composition and pressure show similar exponents in the power laws in MGs, composition and pressure are two independent variables for controlling the density (volume) of materials; they usually have dramatically different effects on MGs. For example, pressure is thought to cause only elastic densification in MGs without obvious structural change because of their already densely packed structure; the structure and properties of MGs are very sensitive to even minor compositional variations (25, 26). In addition, to achieve composition change, different samples usually have to be synthesized. And, many other variables are thought to be inevitably involved, making the compositional change complex (23). Therefore, some basic questions have been perplexing to the glass community: Why do “complex” compositional and “simple” pressure power laws show similar exponents? Is there any connection between them? These questions remain unanswered and have been the major obstacle in understanding the nature of these noncubic power laws.To address these questions, a systematic study in the 2D pressure-composition space seems to be required. However, the consistency of the data in this kind of study will be questionable. Alternatively, in the present study, we choose the polyamorphous Ce₆₈Al₁₀Cu₂₀Co₂ MG as a model system. It is well known that Ce-based MG systems show a polyamorphic transition between ∼2 GPa and ∼5 GPa caused by the pressure-induced 4f electron localized-to-itinerant transition (27, 28). During this polyamorphic transition, both the atomic size and the electronegativity of Ce are significantly changed (29). Composition tuning in MGs mainly means the variation of atomic size and electronegativity of components, which controls the formation of MGs (30). Therefore, although nothing changes in the nucleus, for MGs this pressure-induced polyamorphic transition is equivalent to a continuous “composition” change with the 4f-localized “big Ce” gradually substituted by 4f-itinerant “small Ce.” As a result, we are able to vary both pressure and composition of a MG in a well-controlled way for the first time, to our knowledge.     

Ultrastructural and phenotypic analysis of in vitro erythropoiesis from human cord blood CD34<Superscript>+</Superscript> cells

Erythropoietin (EPO) induces erythropoiesis in vitro as well as in vivo, and the process of erythroid differentiation has been explored phenotypically and morphologically. However, morphological analysis of in vitro erythropoiesis of human hematopoietic progenitor cells at the ultrastructural level has not been reported before. In the present study, we have traced the ultrastructural changes of erythroid differentiation during ex vivo expansion of human cord blood (CB) CD34(+) cells in the presence of EPO by electron microscopy (EM), along with concurrent phenotypic analysis. CD34(+) cells purified from ten CBs by immunomagnetic selection were cultured in serum-free essential media in the presence of a combination of the several cytokines including EPO, thrombopoietin, flt3-ligand (FL), stem cell factor (SCF), granulocyte colony-stimulating factor, interleukin (IL)-3 and/or IL-11. Phenotypic analysis was performed by flow cytometric analysis for erythroid markers, including glycophorin C (GPC), Kell-related, glycophorin A (GPA), band 3, Lu(b), and RhD. Ultrastructural analysis was performed by electron-microscopic examination of the cultured cells stained with uranyl acetate and lead citrate. Phenotypic analysis revealed that in the absence of EPO, genuine erythroid fraction expressing the typical pattern of erythroid markers did not appear. The order of the above markers expressed in the cultured cells in the presence of EPO was GPC, Kell-related, GPA, band 3, Lu(b), and RhD, irrespective of the type of cytokine added. Of the cytokines used in combination with EPO, FL + IL-3 was the most efficient in inducing erythroid differentiation, which was followed by SCF + IL-3. EM examination demonstrated complete process of erythroid development from pronormoblasts to reticulocytes with nuclei having been extruded and mature erythrocytes. These results suggest that morphologically intact erythrocytes could be produced by ex vivo expansion of CB CD34(+) cells using EPO.     

Up-regulation and co-expression of fibroblast growth factor receptors in human gastric cancer

Fibroblast growth factor (FGF), a key regulatory factor of cell growth and differentiation, is involved in embryonic development, angiogenesis, and tumorigenesis. To date, four different FGF receptors (FGFRs) have been cloned and characterized. We examined the expression of four FGFRs in human gastric cancer tissues and cell lines using Northern analysis, ribonuclease protection assay, and immunohistochemistry. The mRNAs of FGFR-1 (10/14), FGFR-2 (9/14), and FGFR-4 (9/14) were up-regulated in cancer compared with normal tissues. FGFR-3 mRNAs were barely detectable in both normal and cancer tissues. These FGFR mRNAs were co-expressed in various combinations of two or three in the same tissue. Immunohistochemistry confirmed specific staining of multiple FGFRs, except FGFR-3, in the cancer specimens. To investigate the functional significance of FGFR co-expression we examined the invasive property of SNU-16 cells, which exhibited gene amplification of FGFR-2, -3, and -4 as well as over-expression of keratinocyte growth factor receptor (KGFR), a splice variant of FGFR-2, and FGFR-4 mRNA. KGF plus acidic FGF (aFGF), KGF, and aFGF treatment enhanced the invasive potential of SNU-16 cells over the control by 100%, 107%, and 47%, respectively, indicating that neither additive nor synergistic effect was induced by stimulation with aFGF plus KGF. These results suggest that co-expression of FGFRs in various combinations may cause subtle changes in the progression of gastric cancer. Received: 16 February 1999 / Accepted: 6 March 2000     

Correlation between hMLH1/hMSH2 and p53 protein expression in sporadic colorectal cancer

BACKGROUND/AIMS: The aim of this study was to analyze expression of hMLH1 and hMSH2 mismatch repair proteins in terms of p53 protein expression and clinicopathological parameters in sporadic colorectal cancer. METHODOLOGY: Four hundred and two cases of curative colorectal surgery for primary colorectal cancer were included in this study (patients with a familial history of colorectal cancer and familial adenomatous polyposis were not included). Clinicopathological parameters were reviewed retrospectively. HMLH1, hMSH2 and p53 protein expression in tumor tissue sections was determined using immunohistochemical staining with specific monoclonal antibodies. RESULTS: Of the 402 cases, immunohistochemical analysis showed 35 (8.7%) had loss of expression of hMLH1, 19 (4.7%) had loss of expression of hMSH2, and three cases (0.7%) had loss of expression of both proteins. Multivariate analysis showed that early age of onset (p=0.023), right side dominance (p<0.001) and poorly differentiated or mucinous cell type (p<0.001) were associated with loss of expression of hMLH1 or hMSH2. Loss of expression of hMLH1 or hMSH2 correlated with low p53 expression (p<0.001). In terms of clinicopathological parameters, p53 expression was associated only with hMLH1 or hMSH2 expression. CONCLUSIONS: Colorectal cancers not expressing hMLH1 or hMSH2 may have distinct features from those expressing these mismatch repair proteins. p53 expression appears to be implicated in a compensatory pathway with mismatch repair proteins.     

Pilot study of interferon gamma for chronic hepatitis C

BACKGROUND/AIMS: Currently, there are no effective therapies available for patients with chronic hepatitis C who have failed to respond to optimal interferon alfa-based regimens. The aims of this pilot study were to assess the antiviral activity and safety of interferon gamma in chronic hepatitis C. METHODS: Patients with chronic hepatitis C, genotype 1, who had not responded to or who had relapsed after therapy with interferon alfa and ribavirin were enrolled in a trial of interferon gamma 1b given in doses of 100, 200 or 400 microg subcutaneously three times weekly for 4 weeks. Frequent blood samples were obtained for HCV RNA levels. RESULTS: Fourteen patients were enrolled. Geometric mean HCV RNA levels remained unchanged. Serum aminotransferase levels also did not change, while there were significant decreases in neutrophil counts (-41% from baseline) and hematocrit (-5%). Low grade fever and malaise were common with the first injection of interferon gamma, but no serious side effects were encountered. CONCLUSIONS: Although relatively well tolerated, interferon gamma in doses of 100-400 microg thrice weekly had no effect on HCV RNA levels in patients with chronic hepatitis C who had failed to achieve a sustained response to interferon alfa-based therapies.     

Prognostic significance of p53 overexpression after hepatic resection of hepatocellular carcinoma.

BACKGROUND/AIMS: p53 mutation is the most common genetic abnormality in human cancers. However, although it has been reported that p53 overexpression in hepatocellular carcinoma (HCC) is associated with the aggressive behavior of tumor, the prognostic significance of p53 overexpression in HCC remains controversial. The aims of the present study were to examine the correlations between p53 overexpression and the clinicopathologic parameters of HCCs, and to determine the prognostic significance of p53 overexpression in HCC. METHODS: Immunohistochemical analysis of p53 overexpression was performed in 105 consecutive cases of HCC who underwent curative hepatic resection. Survival curves were calculated using the Kaplan-Meier method and multivariate analysis of outcome predictors for HCCs was assessed by logistic regression analysis. RESULTS: p53 overexpression was observed in 20 of 105 HCCs (19.0%). Multivariate analysis identified significant correlations between p53 overexpression and microvascular invasion (p=0.027), liver cirrhosis (p=0.035), 1-year survival rate (p=0.016), multiple tumors (p=0.014), and the presence of tumor capsule (p=0.010). The 2-year survival rate was poorer in patients without tumor capsule (p=0.043). CONCLUSIONS: Our results show a positive association between p53 overexpression and microvascular invasion in HCC, and indicate that p53 overexpression is a poor prognostic factor of survival, especially within 1 year after liver resection in HCC patients.     

Bone scintigraphy of skeletal metastasis in hepatoma patients treated by TAE

BACKGROUND/AIMS: Skeletal metastasis in hepatocellular carcinoma patients has become clinically important as a result of advances in treatment modalities. However, the diagnostic accuracy of bone scintigraphy in hepatocellular carcinoma has been questioned. METHODOLOGY: 99mTc-MDP bone scintigraphy was performed in 63 unresectable hepatocellular carcinoma patients treated by transcatheter arterial embolization who either developed musculoskeletal pain (n = 43) or elevated serum alpha-fetoprotein levels (n = 20) during follow-up. Results were categorized as positive or negative for metastases, and their accuracy was evaluated by radiological studies, biopsy, and clinical follow-up. RESULTS: Bone scintigraphy was positive in 22/43 (51.2%) subjects with pain and 2/20 with alpha-feto-protein elevation. Among 24 bone scintigraphy(+) patients, metastasis was confirmed in 17 and excluded in 6. Frequent sites for metastatic bone scintigraphy lesions were the spine, pelvic bone and ribs. Although 8 metastatic lesions had low or mixed uptake, most had increased uptake on bone scintigraphy. Among 39 bone scintigraphy(-) patients, metastasis was excluded in 32 and confirmed in 1. The sensitivity and specificity of bone scintigraphy in this subset of patients was 94.4% and 84.2%, respectively. CONCLUSIONS: Transcatheter arterial embolization treated hepatocellular carcinoma patients with musculoskeletal pain have a high likelihood of bone metastasis, and bone scintigraphy is a highly reliable method for its detection.     

High-performance thin H:SiON OLED encapsulation layer deposited by PECVD at low temperature

Highly moisture permeation resistive and transparent single layer thin films for the encapsulation of hydrogenated silicon oxynitrides (H:SiON) were deposited by plasma-enhanced chemical vapor deposition (PECVD) using silane (SiH₄), nitrous oxide (N₂O), ammonia (NH₃), and hydrogen (H₂) at 100 °C for applications to a top-emission organic light-emitting diode (TEOLED). Addition of H₂ into the PECVD process of SiON film deposition afforded the hydrogenated SiON film, which showed not only improved optical properties such as transmittance and reflectance but also better barrier property to water permeation than PECVD SiON and even SiN_x. The H:SiON film with thickness of only 80 nm exhibited water vapor transmission rate (WVTR) lower than 5 × 10⁻⁵ g per m² per day in the test conditions of 38 °C and 100% humidity, where this WVTR is the measurement limit of the MOCON equipment. An additional coating of UV curable polymer enabled the H:SiON films to be flexible and to have very stable barrier property lower than 5 × 10⁻⁵ g per m² per day even after a number of 10k times bending tests at a curvature radius of 1R. The mild H:SiON film process improved the electrical properties of top-emission OLEDs without generating any dark spots. Furthermore, single H:SiON films having high water vapor barrier could maintain the original illumination features of TEOLED longer than 720 hours. These excellent properties of the H:SiON thin films originated from the structural changes of the SiON material by the introduction of hydrogen.

High-performance H:SiON single layer thin film encapsulation (TFE) was deposited by plasma enhanced chemical vapor deposition (PECVD) method. To control the characteristics of the SiON thin films, hydrogen gas was introduced during PECVD process.