A novel nucleolar G-protein conserved in eukaryotes

We describe here a novel, evolutionarily conserved set of predicted G-proteins. The founding member of this family, TbNOG1, was identified in a two-hybrid screen as a protein that interacts with NOPP44/46, a nucleolar phosphoprotein of Trypanosoma brucei. The biological relevance of the interaction was verified by co-localization and co-immunoprecipitation. TbNOG1 localized to the trypanosome nucleolus and interacted with domains of NOPP44/46 that are found in several other nucleolar proteins. Genes encoding proteins highly related to TbNOG1 are present in yeast and metazoa, and related G domains are found in bacteria. We show that NOG1 proteins in humans and Saccharomyces cerevisae are also nucleolar. The S. cerevisae NOG1 gene is essential for cell viability, and mutations in the predicted G motifs abrogate function. Together these data suggest that NOG1 may play an important role in nucleolar functions. The GTP-binding region of TbNOG1 is similar to those of Obg and DRG proteins, which, together with NOG, form a newly recognized family of G-proteins, herein named ODN. The ODN family differs significantly from other G-protein families, and shows several diagnostic sequence characteristics. All organisms appear to possess an ODN gene, pointing to the biological significance of this family of G-proteins.

Identification, expression, and nuclear location of murine Mage-b2 protein, a tumor-associated antigen

MAGE-1, which was originally identified by reacting with cytolytic T lymphocytes derived from the blood of melanoma patients, is a member of a gene family consisting of 17 structurally related genes. The MAGE genes are expressed only in the testis among normal tissues and in a number of human tumors of various histological types. Murine MAGE (also called SMAGE or Mage) genes were found in a study aimed at detecting mouse genes homologous to human MAGE genes. However, the biological functions of MAGE and Mage are currently unknown. To understand the biological functions of Mage, in the present study a recombinant SMAGE2 (Mage-b2) protein of 43 kDa was produced and monoclonal antibodies reactive with Mage-b2 protein were generated. One monoclonal antibody, smpG4A, specifically recognized a 43 kDa protein in lysates of Mage-b2 mRNA-positive sarcoma cells and of the testis. Immunohistochemistry showed that Mage-b2 is located in the nucleus of Mage-b2 mRNA-positive sarcoma cells. These results should contribute to understanding the biological functions of Mage.

Downregulation of MHC class II expression by oxidant-induced apoptosis in EBV-transformed B-cells

The expression of MHC class II molecules is actively regulated upon various cellular stimuli. Since apoptosis is an inducible cellular process, it was asked whether cells undergoing apoptosis would also modulate their expression of class II molecules. Using an EBV-transformed B-cell line, the cell surface expression of HLA-DR molecules was analyzed by fluorescence-activated flow cytometry on normal and oxidant-treated apoptotic cells. A rapid and continuous decrease in HLA-DR expression was observed in apoptotic cells. RNA analysis and semiquantitative RT-PCR of cytoplasmic beta-actin mRNA showed that apoptotic cells contain partially degraded RNA and much lower amounts of beta-actin mRNA. Nevertheless, when compared after normalization of intact mRNA amounts, the HLA-DRB mRNA signals were of similar strength in normal and apoptotic cells as determined by semiquantitative RT-PCR. Thus, the decrease in the number of class II molecules during apoptosis underlies no specific program for downregulation of HLA-DRB mRNA transcription but is due to a nonspecific degradation of RNA molecules accompanied by cell death.

Dammarane derivatives protect cultured rat cortical cells from glutamate-induced neurotoxicity

We previously reported that ginsenosides Rb1 and Rg3, dammarane glycosides, of Panax ginseng C. A. Meyer (Araliaceae), significantly attenuated glutamate-induced neurotoxicity in primary cultures of rat cortical cells. To seek more potent neuroprotective compounds, we attempted to modify the chemical structure of dammarane glycosides and obtained six derivatives, MA-11, PT-11, PT-111, POA-101, POA-111 and N-001. The neuroprotective activity of these dammarane derivatives were evaluated employing primary cultures of rat corticoid cells. The glutamate-induced neuronal cell damage was significantly reduced by a pre-treatment with protopanaxadiol, MA-11 or PT-11 at concentrations ranging from 100 nM to 10 microM. Both MA-11 and PT-11, preserved the levels of catalase and inhibited decreases in glutathione reductase in glutamate-injured cells. Furthermore, the dammarane derivatives reduced the content of intracellular peroxide in glutamate-intoxicated cells. Finally, they inhibited the formation of malondialdehyde, a compound produced during lipid peroxidation, in glutamate-insulted cells. These results show that the dammarane derivatives, MA-11 and PT-11, exert significant neuroprotective effects on cultured cortical cells by a mechanism seemingly distinct from that afforded by ginsenosides Rb1 and Rg3. As such, the dammarane derivatives may be efficacious in protecting neurons from oxidative damage caused by exposure to excess glutamate.

Differential validity of the Defense Mechanism Manual for the TAT between Asian Americans and Whites. Thematic Apperception Test

Thematic Apperception Test (Murray, 1943) responses of 69 Asian American (hereafter, Asian) and 83 White students were coded for defenses according to the Defense Mechanism Manual (Cramer, 1991b) and studied for differential validity in predicting paper-and-pencil measures of relevant constructs. Three tests for differential validity were used: (a) differences between validity coefficients, (b) interactions between predictor and ethnicity in criterion prediction, and (c) differences between groups in mean prediction errors using a common regression equation. Modest differential validity was found. It was surprising that the DMM scales were slightly stronger predictors of their criteria among Asians than among Whites and when a common predictor was used, desirable criteria were overpredicted for Asians, whereas undesirable ones were overpredicted for Whites. The results were not affected by acculturation level or English vocabulary among the Asians.

Efficiency of promoter and cell line in high-level expression of erythropoietin

Efficiency of viral promoters and various cell lines in directing high-level expression of human erythropoietin (Epo) was investigated. To investigate the effects of various viral promoters and cell lines on the Epo expression level, genomic Epo with the 5' and 3' untranslated regions (UTRs) deleted was cloned next to the simian virus 40 early promoter, cytomegalovirus early promoter or SRalpha promoter. These expression vectors were transfected into COS-7, BHK-21 and Chinese hamster ovary (CHO)/dhfr(-) cells, respectively. The COS-7 cells transfected with the vector containing the SRalpha promoter showed the highest expression level ( approximately 103 IU/ml) at 72 h post-transfection. For the development of Epo-producing stable cell lines, BHK-21 and CHO/dhfr(-) cells transfected with the 5',3'-UTR-deleted genomic Epo under the control of the SRalpha promoter were cultured with media containing zeocin. Several clones of zeocin-resistant BHK-21 and CHO/dhfr(-) cells were cultured in the presence of methotrexate (MTX). A BHK-21 clone selected in the presence of 500 nM MTX expressed and secreted approximately 490 IU/ml Epo into the medium. A CHO/dhfr(-) clone selected in the presence of 20 nM MTX expressed and secreted approximately 45 IU/ml Epo into the medium. Southern-blot analysis indicated that enhancement of Epo expression in the MTX-resistant stable cells might be related to the amplification of gene copy number.

In vitro binding analysis of hepatitis B virus preS-derived putative helper T-cell epitopes to MHC class II molecules using stable HLA-DRB1*0405/DRA*0101 transfected cells

In designing epitope-based vaccines, the inclusion of a helper T-lymphocyte (HTL) epitope is necessary to elicit both humoral and cellular immune responses. Whereas the preS region of the hepatitis B virus (HBV) surface antigen is well-known to raise protective immunity, the epitopes for activating HTLs are poorly characterized. In an attempt to identify such epitopes, the HBV-preS region was screened for peptide sequences with HLA-DR4 binding motifs, and putative HTL candidate peptides were synthesized in a biotinylated form. Using L929 mouse fibroblasts stably transfected with HLA-DRB1*0405 and HLA-DRA*0101 cDNA, specific binding of the peptides was then detected using fluorescence-conjugated streptavidin. The cell-surface expression of HLA-DR molecules on transfectants was confirmed by confocal microscopy, and quantitative analysis of candidate peptide binding was performed by fluorescence activated cell sorting. Among eight preS-derived peptides, three candidate peptides-namely preS1(23-33), preS1(62-72), and preS1(76-86)-showed good binding characteristics to HLA-DR4 molecules, among which the preS1(23-33) epitope was regarded as the most promising HTL epitope. Further studies with these candidate HTL stimulatory peptides will show their ability to activate the human immune system against HBV.

Steaming of ginseng at high temperature enhances biological activity

The present study was performed to evaluate the effect of steaming ginseng at a temperature over 100 degrees C on its chemical constituents and biological activities. Raw ginseng was steamed at 100, 110, and 120 degrees C for 2 h using an autoclave. The ginseng steamed at 120 degrees C was more potent in its ability to induce endothelium-dependent relaxation. Steaming the raw ginseng at 120 degrees C also remarkably increased the radical-scavenging activity. Ginsenosides F(4), Rg(3), and Rg(5), which were not present in raw ginseng, were produced after steaming. Ginsenosides Rg(3) and Rg(5) were the most abundant ginsenosides in the ginseng steamed at 120 degrees C, accounting for 39% and 19% of all ginsenosides, respectively.

Gene expression profile and identification of differentially expressed transcripts during human intrathymic T-cell development by cDNA sequencing analysis

The development of immature thymocytes to mature T-lymphocytes is a central process for establishing a functional immune system. The gene regulatory events involved in this process are of outstanding interest in understanding the generation of the T-cell repertoire as well as the differentiation of lineage-specific cells, such as CD4(+) helper T-cells or CD8(+) cytotoxic T-lymphocytes. While some essential genes involved in lineage decision and thymocyte differentiation have been already identified, the exact regulatory mechanisms and differential gene expressions are still unknown. The present study was performed to analyze the gene expression profile during T-cell development, in particular, during the differentiation of immature thymocytes into CD4(+) mature T-cells by analyses of expressed sequence tags (ESTs), and to elucidate novel human genes involved in this process. Based on distinct developmental stages, three PCR-based cDNA libraries from immature CD3(-),4(-),8(-) triple-negative, CD4(+),8(+) double-positive, and mature CD4(+),8(-) single-positive thymocytes were constructed. A total of 1477 randomly selected clones were analyzed by automated single-pass sequencing, and the assembly of ESTs resulted in 1027 different species of contig sequences. Among them, 392 contig sequences were matched to known genes, and several novel transcripts were discovered. The matched clones were classified into seven categories according to their functional aspects, and the gene expression profiles of the three thymocyte subsets were compared. The information obtained in current study will serve as a valuable resource for elucidating the molecular mechanism of intrathymic T-cell development.

Longitudinal study of dust and airborne endotoxin in the home

To characterize the seasonal variability of endotoxin levels, we measured endotoxin in dust from the bed, bedroom floor, and kitchen floor in 20 homes, and in air from the bedroom in 15 of the homes. All homes were located in the greater Boston, Massachusetts, area and were sampled each month from April 1995 to June 1996. Outdoor air was collected at two locations. We found greater within-home than between-home variance for bedroom floor, kitchen floor, and airborne endotoxin. However, the reverse was true for bed dust endotoxin. Thus, studies using single measurements of dust endotoxin are most likely to reliably distinguish between homes if bed dust is sampled. Dust endotoxin levels were not significantly associated with airborne endotoxin. Airborne endotoxin was significantly (p = 0. 04) and positively associated with absolute humidity in a mixed-effect model adjusting for a random home effect and fixed effect of sampling month and home characteristics. This finding implies that indoor humidity may be an important factor controlling endotoxin exposure. We found a significant (p < 0.05) seasonal effect in kitchen floor dust (spring > fall) and bedroom airborne endotoxin (spring > winter), but not in the other indoor samples. We found significant seasonal pattern in outdoor airborne endotoxin (summer > winter).

Microsatellite alteration in histologically normal lung tissue of patients with non-small cell lung cancer

Microsatellite alteration (MSA) has been observed in a fraction of non-small cell lung cancer (NSCLC). Most prior studies regarding MSA in lung cancer have usually used adjacent non-malignant lung tissues as a source of constitutional DNA. However, these normal tissues might have genetic alterations because the entire field of bronchial tree is exposed to the same carcinogenic insult. The aim of this study was to search if MSA is present in the histologically normal lung tissue of patients with NSCLC. Tumor and corresponding normal lung tissue specimens were obtained from 20 patients with NSCLC. Normal lung tissue specimens were obtained from either the opposite end of resected surgical samples or as distant from the tumor as possible. They were examined histopathologically and confirmed as normal by H-E stain. Patients' peripheral lymphocytes were used as the source for the normal DNA. Sixteen markers on 3p and 9p (nine and seven markers, respectively) were used. MSA was detected in seven of 20 (35%) histologically normal lung tissue specimens at a frequency similar to that observed in tumor tissue (eight of 20, 40%). Five cases showed MSA in both normal lung tissue and the corresponding tumor. In these five cases, MSA in normal lung tissue was detected at the same microsatellite markers which MSA was detected in the corresponding tumor. The number and size of novel bands in normal lung tissue was identical to that in tumor tissue except in one case. In which case, the same pattern of MSA was found in both normal lung tissue and corresponding tumor tissue at two markers. However, at one marker, while one identical novel band was detected in normal lung tissue and corresponding tumor tissue, another novel band was found only in tumor tissue. In two of 12 patients whose tumor was negative for the presence of MSA, MSA was detected in normal lung tissue. These results indicate that genetic alterations are widely distributed in the lung tissue of patients with lung cancer and provide considerable support for the field cancerization theory. Screening for MSA in resected normal lung tissue might be a new method to identify patients at high risk for developing second primary lung cancers.

Pulmonary vasculitis: the spectrum of radiological findings

Pulmonary vasculitis includes various disease entities with a wide range of clinical presentations and overlapping imaging features. Radiological findings of vasculitis in the angiitis-granulomatosis group are nodular and patchy opacities, whereas the principal feature of those diseases causing widespread capillaritis is diffuse air space consolidation. Aneurysms or stenoses of pulmonary arteries are seen in patients with Takayasu arteritis or Behçet's disease.

Detection of cellular receptors specific for the hepatitis B virus preS surface protein on cell lines of extrahepatic origin

Hepatitis B virus infection is primarily mediated by the interaction of the preS region of the viral envelope protein with its still unknown cellular receptor. Using recombinantly expressed preS proteins, the distribution of preS-binding receptors on cell lines from extrahepatic origins was determined by immunofluorescence and flow cytometry. In contrast to human liver cell lines, most cell lines from extrahepatic origins did not bind preS proteins. Nevertheless, exceptions were found in the bone marrow-derived cell line, KG-1, and the osteogenic sarcoma cell line SaOS-2, as well as in the previously reported EBV-transformed B-cell line, Wa. To determine the biochemical nature of these receptors, Wa-cells were cell surface biotinylated and the preS-binding receptors were isolated by immunoprecipitation. A specific band with a molecular weight of approximately 30 kDa was identified in a SDS-polyacrylamide gel, which further characterization is expected to provide clues regarding the infection mechanism of HBV in hepatic- and extra-hepatic cells.

Influence of the sequence variations of the HLA-DR promoters derived from human melanoma cell lines on nuclear protein binding and promoter activity

In previous studies we reported that the expression of HLA-DR on melanoma cell lines was differentially modulated by IFN- gamma and that the transcription rate was responsible for this differential modulation. We have also reported the nucleotide sequence variations in the promoter region of HLA-DR genes, and proposed that differences in the promoter activity by the sequence variations of the HLA-DR promoters might contribute to such a differential transcriptional regulation at the promoter level. In this study, in order to assess whether the sequence variations of the HLA-DR promoters affect the factor binding and exert influence on the promoter activity, nuclear factor binding to our previous six HLA-DRA and fourteen HLA-DRB promoter clones was evaluated with the nuclear protein extracted from a B-lymphoblastoid cell line (BLCL), BH, together with the chloramphenicol acetyltransferase (CAT) reporter assay. In the HLA-DRA promoters, clone #35 containing one bp nucleotide sequence variation at the octamer binding site (OCT) (GATTTGC to GATCTGC) showed relatively weak factor binding. In the HLA-DRB promoters, clusters I, III, and IV of our previous HLA-DRB promoter homologues, containing one bp nucleotide sequence variation (GATTCG) in their Y boxes exhibited weak factor binding and CAT activity compared to other clusters (GATTGG) that showed strong factor binding and CAT activity. This data suggests chat the binding patterns of transcription factors influenced by the nucleotide sequence variations of the HLA-DR promoter could affect the promoter activity and the DNA sequence elements in the HLA-DR promoter could mediate transcriptional regulation.

Determinants of plasma total homocysteine levels in Korean chronic renal transplant recipients

OBJECTIVE

Study the determinants of plasma total homocysteine (tHcy) levels, such as fasting levels of serum creatinine (SCr), albumin, plasma tHcy, folate, B(12), and pyridoxal-5'-phosphate (PLP) in chronic Korean renal transplant recipients (RTR).

DESIGN

Cross-sectional study.

SETTING

Nephrology & Transplant Service in Catholic University Kangnam St. Mary's Hospital, Seoul, Korea.

PARTICIPANTS

Ninety-one chronic Korean RTR with stable renal function who were > or =6 months post-transplant.

MEASURES

Used medical record review and anthropometric measurements, and overnight (10 to 14 hours) fasting blood samples were measured for plasma tHcy, PLP, folate, B(12), SCr, and albumin.

RESULTS

The prevalence of hyperhomocysteinemia (tHcy > 12 micromol/L) was 56%, and 47% had low plasma folate levels (<3 ng/mL). Linear modeling with analysis of covariance adjusted for age, sex, albumin, SCr, and plasma B-vitamin status revealed that only SCr (standard regression coefficient R = +0.663, P<.001), plasma folate (R = -0.276, P =.001), and B(12) (R = -0.149, marginal, P =.08) were independent determinants of fasting tHcy levels in this patient population.

CONCLUSION

Renal function is the major independent determinant of the fasting tHcy levels among chronic, stable Korean RTR, and that B-vitamin status plays a secondary role among such patients.

Direct competitive enzyme-linked immunosorbent assay for sulfamethazine

A direct competitive enzyme-linked immunosorbent assay (ELISA) for screening sulfamethazine (SMZ) in pork tissues was developed. The assay was made with the affinity-purified polyclonal antibody-coated microtiter plate. A cross reactivity of IgG was observed at 3.5 microg/g of sulfamerazine among nine kinds of sulfonamide tested. Pork tissues fortified with SMZ was mixed with octadecyl silica (C18), and extracted with dichloromethane. The extracted SMZ was measured by homemade ELISA, commercial ELISA, and HPLC. The results were correlated (r=0.993, p<0.01). The homemade ELISA was sensitive to determine SMZ at the maximum residue level (MRL) as commercial one. During stability test of the IgG coated microtiter plate performed at 40 degrees C for 14 days, no difference in sensitivity was observed. We developed homemade ELISA with a detection limit of 10 ng of SMZ per g of pork tissues, and it could be used to screen SMZ in pork tissues.

Restoration of P-glycoprotein function is involved in the increase of natural killer activity with exogenous interleukin-15 in human immunodeficiency virus-infected individuals

A depressed level of natural killer (NK) activity is one of the various immunologic abnormalities in human immunodeficiency virus (HIV) infection. Interleukin-15 (IL-15), an immunotherapeutic candidate in HIV infection, increases NK activity and induces the excretion of CC-chemokines from divergent immune cells, but the mechanisms of NK activity enhancement by IL-15 stimulation is not clearly established in HIV infection. This study examined whether CC-chemokines, which are known to increase NK activity, are secreted adequately in HIV-infected individuals, and also investigated whether P-glycoprotein is involved in NK activity enhancement after IL-15 administration. NK activity increased with IL-15 stimulation in NK cells of HIV-infected individuals, as it does in normal NK cells. IL-15 stimulates NK cells to secrete CC-chemokines, such as, macrophage inflammatory protein-1alpha (MIP-1alpha), macrophage chemotactic protein-1alpha (MCP-1alpha) and regulated upon activation, normal T cells expressed and secreted (RANTES) in both HIV-infected individuals and controls with no significant difference. P-glycoprotein expression and function is decreased in HIV-infected individuals and restored only in NK cells of HIV-infected individuals after IL-15 stimulation. P-glycoprotein may play a role in the mechanism of increased NK cell activity in HIV-infected individuals after IL-15 stimulation.

Muscle abnormalities in juvenile dermatomyositis patients: P-31 magnetic resonance spectroscopy studies

OBJECTIVE

To characterize metabolic abnormalities in the muscles of children with the juvenile variant of dermatomyositis (JDM) by the use of noninvasive P-31 magnetic resonance spectroscopy (MRS).

METHODS

Thirteen patients with JDM (ages 4-16 years) were studied. Biochemical status was evaluated with P-31 MRS by determining the concentrations of the high-energy phosphate compounds, ATP and phosphocreatine (PCr), ratios of inorganic phosphate (Pi) to PCr (Pi:PCr ratio), levels of free cytosolic ADP, and phosphorylation potentials (PPs) during rest, exercise, and recovery.

RESULTS

Significant metabolic abnormalities were observed in the thigh muscles of 10 severely affected patients during rest, 2 graded levels of exercise, and recovery. Mean ATP and PCr levels in the muscles of JDM patients were 35-40% below the normal control values (P < 0.003). These data, along with elevated Pi:PCr ratios, higher ADP levels, and abnormal values for PPs, indicated defective oxidative phosphorylation in the mitochondria of diseased JDM muscles. MRS findings were normal in 2 additional patients who had improved with prednisone treatment and in 1 patient who had no muscle weakness (amyopathic variant of JDM).

CONCLUSION

JDM patients can be monitored with noninvasive P-31 MRS without sedation. Biochemical defects in energy metabolism are concordant with the weakness and fatigue reported by JDM patients. Quantitative MRS data are useful for evaluating patients and optimizing drug treatment regimens.