Relative biological efficiency for the induction of various gene mutations in normal and enriched with 10B Tradescantia cells by neutrons from 252Cf source

The effectiveness of neutrons from a Californium-252 source in the induction of various abnormalities in the Tradescantia clone 4430 stamen hair cells (Trad-SH assay) were studied. A special attention was paid to check whether any enhancement in effects is visible in the cells enriched with boron ions. Inflorescences, normal or pretreated with chemicals containing boron, were irradiated in the air with neutrons from a 252Cf source at KAERI, Taejon, Korea. To estimate the relative biological effectiveness (RBE) of the beam under the study, numbers of Tradescantia inflorescence without chemical pretreatment were irradiated with various doses of X-rays. The ranges of radiation doses used for neutrons were 0-1.0Gy and for X-rays 0-0.5Gy. Following the culturing according to standard procedures screening of gene and lethal mutations in somatic cells of stamen hairs was done in the extended period, between days 7 and 19 after exposures. Maximal RBE values for the induction of pink, colorless and lethal mutations were evaluated from comparison of the slopes in linear parts of the dose response curves obtained after irradiation with X-rays and californium source. The RBE(max) value or the induction of gene mutation was estimated as 7.2 comparing the value 5.6 in the studies reported earlier. The comparison of dose-response curves and its alteration, due to changes in the cells and plants environment during and after irradiation, explains the observed differences. Inflorescence pretreated with borax responded to neutrons differently depending on the biological end points. Although, for the induction of pink mutations no significant difference was observed, though, in the case of cell lethality, pretreated with boron ion plants have shoved a statistically significant increase of the RBE value from 5.5 to 34.7, and in the case of colorless mutations from 1.6 to 5.6.

Adipose-selective targeting of the GLUT4 gene impairs insulin action in muscle and liver

The earliest defect in developing type 2 diabetes is insulin resistance, characterized by decreased glucose transport and metabolism in muscle and adipocytes. The glucose transporter GLUT4 mediates insulin-stimulated glucose uptake in adipocytes and muscle by rapidly moving from intracellular storage sites to the plasma membrane. In insulin-resistant states such as obesity and type 2 diabetes, GLUT4 expression is decreased in adipose tissue but preserved in muscle. Because skeletal muscle is the main site of insulin-stimulated glucose uptake, the role of adipose tissue GLUT4 downregulation in the pathogenesis of insulin resistance and diabetes is unclear. To determine the role of adipose GLUT4 in glucose homeostasis, we used Cre/loxP DNA recombination to generate mice with adipose-selective reduction of GLUT4 (G4A-/-). Here we show that these mice have normal growth and adipose mass despite markedly impaired insulin-stimulated glucose uptake in adipocytes. Although GLUT4 expression is preserved in muscle, these mice develop insulin resistance in muscle and liver, manifested by decreased biological responses and impaired activation of phosphoinositide-3-OH kinase. G4A-/- mice develop glucose intolerance and hyperinsulinaemia. Thus, downregulation of GLUT4 and glucose transport selectively in adipose tissue can cause insulin resistance and thereby increase the risk of developing diabetes.

2,2-Dimethyl-4,5-diaryl-3(2H)furanone derivatives as selective cyclo-oxygenase-2 inhibitors

A series of 2,2-dimethyl-5-[4-(methylsulfonyl)phenyl]-4-phenyl-3(2H)furanones was prepared and evaluated for their ability to inhibit cyclo-oxygenase-2 (COX-2).

Insulin/IGF-1 and TNF-alpha stimulate phosphorylation of IRS-1 at inhibitory Ser307 via distinct pathways

Serine/threonine phosphorylation of IRS-1 might inhibit insulin signaling, but the relevant phosphorylation sites are difficult to identify in cultured cells and to validate in isolated tissues. Recently, we discovered that recombinant NH2-terminal Jun kinase phosphorylates IRS-1 at Ser307, which inhibits insulin-stimulated tyrosine phosphorylation of IRS-1. To monitor phosphorylation of Ser307 in various cell and tissue backgrounds, we prepared a phosphospecific polyclonal antibody designated alphapSer307. This antibody revealed that TNF-alpha, IGF-1, or insulin stimulated phosphorylation of IRS-1 at Ser307 in 3T3-L1 preadipocytes and adipocytes. Insulin injected into mice or rats also stimulated phosphorylation of Ser307 on IRS-1 immunoprecipitated from muscle; moreover, Ser307 was phosphorylated in human muscle during the hyperinsulinemic euglycemic clamp. Experiments in 3T3-L1 preadipocytes and adipocytes revealed that insulin-stimulated phosphorylation of Ser307 was inhibited by LY294002 or wortmannin, whereas TNF-alpha-stimulated phosphorylation was inhibited by PD98059. Thus, distinct kinase pathways might converge at Ser307 to mediate feedback or heterologous inhibition of IRS-1 signaling to counterregulate the insulin response.

Mechanism of refractory ceramic fiber- and rock wool-induced cytotoxicity in alveolar macrophages

OBJECTIVES

Man-made vitreous fibers (MMVFs) can induce cytotoxicity in a way similar to that of other particles, including silica and asbestos fibers. However, as yet the mechanism of MMVF-induced cytotoxicity is still not clear. This report aims to clarify the mechanism of MMVF-induced cytotoxicity in the alveolar macrophage (AM). In this mechanism, an attempt to prove the involvement of the adenosine triphosphate (ATP) generation system and the polyinosinic acid-inhibitable scavenger receptors was made.

METHODS

Several parameters were observed for cytotoxicity, such as cell viability, the release of lactic dehydrogenase (LDH) and ATP levels in rat AM's that were treated with refractory ceramic fibers (RF2) and rock wool (RW1). A specially designed ATP generation system was used to determine the effect of MMVF on ATP generation. A scavenger receptor ligand was applied to evaluate the relationship between scavenger receptors and MMVF-induced ATP depletion.

RESULTS

A 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium bromide (MTT) assay indicated that both RF2 and RW1 caused a decrease in cell viability and this decrease was concentration-dependent. RF2 and RW1 increased the release of LDH with increasing fiber concentration. From these parameters, RF2 was shown to exhibit greater cytotoxicity than did RW1. Both fibers decreased the intracellular ATP content and this decrease was concentration-dependent. The decrease was more pronounced in RW1 than in RF2 at all fiber concentrations. These fibers suppressed succinate-triggered oxygen consumption. Polyinosinic acid, a ligand of the scavenger receptor, inhibited the MMVF-induced decrease in ATP concentration.

CONCLUSION

These results suggest that RF2 and RW1 can induce cytotoxicity and ATP depletion in the AM through the polyinosinic acid-inhibitable scavenger receptor. ATP depletion was the important factor in MMVF cytotoxicity, especially by RW1.

Clinical features and prognosis of acute aortic intramural hemorrhage compared with those of acute aortic dissection: a single center experience

The clinical manifestations and natural history of acute aortic intramural hemorrhage are not well characterized. Therefore, we have evaluated the differences in the clinical features and prognosis between acute intramural hemorrhage and acute classic aortic dissection. One hundred two consecutive patients with acute aortic syndrome were diagnosed between November 1994 and May 1999. The clinical features, treatment modalities and survival of these patients were analyzed. Thirty one of the 102 patients (30%) had intramural hemorrhage and 71 (70%) had aortic dissection. Patients with intramural hemorrhage were older than those with aortic dissection (mean ages 67 and 55 years, respectively) (p < 0.001), and intramural hemorrhage showed a lower proportion of type A than did aortic dissection (32% and 58%, respectively) (p = 0.018). The incidence of severe complications was significantly lower in patients with intramural hemorrhage than in those with aortic dissection (19% and 27%, respectively) (p < 0.001). Mean follow-up duration was 23.1+/-16.0 months. The overall death rate for patients with intramural hemorrhage (2 / 31; 6%) tended to be lower than those with aortic dissection (14 / 71; 20%) (p = 0.104). The Stanford classification and treatment modalities were not correlated with death. Late follow-up imaging studies in intramural hemorrhage showed partial to complete resolution of intramural hematoma (9 / 15; 60%). In this study, intramural hemorrhage was fairly common, more frequent among older patients, had a lower proportion of type A, and showed a lower incidence of severe complications and a more favorable prognosis in terms of mortality, than aortic dissection.

Removal of unburned carbon from coal fly ash using a pneumatic triboelectrostatic separator

A pneumatic triboelectrostatic beneficiation system of fly ash was studied using a continuous, bench-scale electroseparator composed of two vertical electrode plates and an ejector-tribocharger. Tests were conducted to evaluate the charge density and the separation efficiency at various operating conditions. It was found that the higher charge densities were obtained at (1) the air flow rate of 1.75 m3/min. (2) the feed rate of less than 50 kg/h. and (3) the relative humidity of less than 30% with use of a stainless ejector tribocharger. With these optimum conditions, the clean ash of less than LOI 3% was recovered with a yield over 75% when operated at the diffuser slit gap of 4mm, the diffuser outlet velocity of 16.1-18.6 m/s, and the distance of 15 cm between diffuser slit and splitter. The optimum feed rate was found to be 740 kg/h per m2 of electrode surface area, which can be used as a scale-up factor of electroseparator.

Double-logarithmic finite-size scaling behavior of the specific heat does not necessarily imply its divergence

In a recent paper [Phys. Rev. E 60, 3823 (1999)] Mazzeo and Kuhn presented very careful analyses of the finite-size scaling (FSS) data obtained from the numerical transfer matrix technique. In this report, as a complement to that paper, a critical argument based on numerical evidence is given against the conventional interpretation of the FSS behavior of the specific heat. The argument is likely to cast doubt on previous claims for numerical evidence for the scenario of a logarithmic correction.

Clinical results of the transjugular intrahepatic portosystemic shunt (TIPS) for the treatment of variceal bleeding

BACKGROUND

Transjugular intrahepatic portosystemic shunt (TIPS) has been popularized for the treatment of refractory variceal bleeding. The aim of this study was to assess the safety and long-term effect of TIPS in the treatment of variceal bleeding that is not controlled with pharmacological and endoscopic treatment.

METHODS

Thirty-six patients who underwent transjugular intrahepatic portosystemic shunt (TIPS) due to refractory variceal bleeding were included in the study. The effectiveness of portal decompression and bleeding control was evaluated. Upper gastrointestinal endoscopy was performed to analyse the degree of varices and portal hypertensive gastropathy (PHG) before TIPS procedure and one to three weeks after TIPS. Angiography was performed in surviving patients, if bleeding recurred, or if ultrasonography or endoscopy suggested stent dysfunction.

RESULTS

TIPS were successfully placed in 36 of 38 patients (94.6%). TIPS achieved hemostasis of variceal bleeding in 34 patients (94.4%). Portal venous pressure decreased from an initial average of 28.7 +/- 7.9 to 23.2 +/- 9.4 mmHg after TIPS (p < 0.05). The portosystemic pressure gradient was significantly decreased from 15.5 +/- 6.3 to 7.8 +/- 4.1 mmHg (p < 0.01). The degree of esophagogastric varices and PHG was significantly improved after TIPS. The total length of follow-up was from one day to 54 months (mean: 355 days). The actuarial probability of survival was 83% at one year and 74% at two years. Overall, 16 episodes of stent dysfunction were diagnosed during follow-up. Stent revision by means of angioplasty was successfully performed in 14 of these episodes.

CONCLUSION

TIPS is an effective and reliable nonoperative means of lowering portal pressure. This procedure has proved useful in the management of acute variceal bleeding refractory to endoscopic treatment. Surveillance by ultrasonography, endoscopy, and angiographic intervention is useful for the maintenance of shunt patency.

Trehalose synthesis by sequential reactions of recombinant maltooligosyltrehalose synthase and maltooligosyltrehalose trehalohydrolase from Brevibacterium helvolum

A DNA fragment encoding two enzymes leading to trehalose biosynthesis, maltooligosyltrehalose synthase (BvMTS) and maltooligosyltrehalose trehalohydrolase (BvMTH), was cloned from the nonpathogenic bacterium Brevibacterium helvolum. The open reading frames for the two proteins are 2,331 and 1,770 bp long, respectively, and overlap by four nucleotides. Recombinant BvMTS, BvMTH, and fusion gene BvMTSH, constructed by insertion of an adenylate in the overlapping region, were expressed in Escherichia coli. Purified BvMTS protein catalyzed conversion of maltopentaose to maltotriosyltrehalose, which was further hydrolyzed by BvMTH protein to produce trehalose and maltotriose. The enzymes shortened maltooligosaccharides by two glucose units per cycle of sequential reactions and released trehalose. Maltotriose and maltose were not catalyzed further and thus remained in the reaction mixtures depending on whether the substrates had an odd or even number of glucose units. The bifunctional in-frame fusion enzyme, BvMTSH, catalyzed the sequential reactions more efficiently than an equimolar mixture of the two individual enzymes did, presumably due to a proximity effect on the catalytic sites of the enzymes. The recombinant enzymes produced trehalose from soluble starch, an abundant natural source for trehalose production. Addition of alpha-amylase to the enzyme reaction mixture dramatically increased trehalose production by partial hydrolysis of the starch to provide more reducing ends accessible to the BvMTS catalytic sites.

Identification of cDNAs encoding two novel nuclear proteins, IMUP-1 and IMUP-2, upregulated in SV40-immortalized human fibroblasts

Using a model system of young, senescent and SV40-immortalized WI-38 fibroblasts, we identified two mRNAs upregulated in immortalized cells (imup-1, immortalization-upregulated protein 1, and imup-2). Compared to normal tissues, both genes were more frequently expressed in cancer cells. The open reading frame of imup-1 spans 321bp, coding for a 10.9 kDa protein of 106 amino acids, while an insertion of 59bp in the otherwise identical mRNA of imup-2 leads to a frameshift, resulting in an 8.5 kDa protein of 85 amino acids. Database searches identified these genes on chromosome 19, which could account for the cloned imup-1 and imup-2 transcripts by alternative splicing. Southern blot analysis of digested genomic DNA confirmed that both transcripts are derived from a single locus. The expressed proteins IMUP-1 and IMUP-2 share 46 identical N-terminal amino acids, whereas the C-termini are unrelated. Green fluorescent protein-fusions of both IMUP-1 and IMUP-2 accumulated in the nucleus of HeLa cells. The C-terminus of IMUP-1 contains a bipartite nuclear localization signal, the deletion of which impaired nuclear translocation. In-vitro translated proteins bound to poly(rG), but did not interact with single-stranded DNA or double-stranded DNA. The nuclear localization of IMUP-1 and IMUP-2 as well as the upregulation of both underlying mRNAs in immortalized cells suggest a function in immortalization.

Characterization of geranium (Pelargonium graveolens) chloroplast EF-Tu cDNA

A geranium (Pelargonium graveolens) chloroplast translational elongation factor EF-Tu (tufA) cDNA was isolated. The geranium tufA cDNA is 1,584 bp long with 20 bp of 5' untranslated region (UTR) and 139 bp of 3' UTR. It encodes 474 amino acids including a putative chloroplast transit peptide of 65 amino acids. The deduced polypeptides of the geranium tufA cDNA contains four GTP binding sequences in its N-terminal region and two chloroplast EF-Tu signature regions in the C-terminal region. The predicted molecular weight of the mature geranium chloroplast EF-Tu protein was about 45,000 and its amino acid sequence identity with the chloroplast EF-Tu proteins of tobacco, pea, Arabidopsis, rice, and soybean ranges from 85% to 91%. The geranium tufA appears to exist as a single copy gene like Arabidopsis and rice, whereas other known dicot plants have more than one copy in their nuclear genomes.

Pentobarbital and ketamine suppress serum concentrations of sex hormones in the female rat

PURPOSE

To investigate the potential effects of pentobarbital and ketamine on serum concentrations of sex hormones, the present study was performed using pregnant mare serum gonadotropin (PMSG)-primed cyclic female Sprague-Dawley rats.

METHODS

Pentobarbital sodium (37 mg.kg(-1), i. p.) or ketamine-hydrochloride (229 mg.kg(-1), i. m.) was injected 2 and 3 days after PMSG treatment. At 0, 1, 2, 3, 4, and 5 days after PMSG treatment, sera were collected by cardiac puncture. The serum concentrations of progesterone (P(4)), testosterone (T), and estradiol-17 beta (E(2)) were determined by radioimmunoassay.

RESULTS

The serum concentrations of P(4) tended to be lower in both the pentobarbital- and the ketamine-treated groups compared with the control group. Significant differences were found on days 3 and 4 after pentobarbital and on days, 1, 4, and 5 after ketamine administration. Serum concentrations of T were also suppressed in both the pentobarbital and the ketamine-treated groups, whereas E(2) concentrations decreased only in the ketamine-treated group.

CONCLUSION

Pentobarbital and ketamine decrease serum sex hormone concentrations in PMSG-primed female rats.

Effects of a hexameric deoxyriboguanosine run conjugation into CpG oligodeoxynucleotides on their immunostimulatory potentials

CpG oligodeoxynucleotides (ODNs) are promising immunomodulatory agents for treating human diseases and vaccine development. Phosphodiester CpG ODNs were demonstrated to have poor immunostimulatory potentials for cytokine production. However, the conjugation of consecutive deoxyriboguanosine residues, called a dG run, at the 3' terminus of phosphodiester CpG ODNs significantly enhanced TNF-alpha and IL-12 production from mouse splenic dendritic cells (DCs). The optimal induction of cytokine production was achieved by the addition of a hexameric dG (dG6) run. In contrast, the existence of a dG6 run either at the 5' terminus of phosphodiester CpG ODNs or at the 3' terminus of phosphorothioate CpG ODNs diminished CpG-mediated cytokine induction, suggesting that the effects of a dG run depend on its location and the chemical property of the ODN backbone, respectively. In addition, we provided the evidence that the conjugation of a dG6 run caused the structural transformation of CpG ODNs, which facilitates their targeting into mouse APCs such as splenic DCs, B cells, and peritoneal macrophages with a scavenger receptor type A ligand specificity. Among primary APCs, DCs were the most potent for CpG ODN-mediated IL-12 production. Furthermore, we demonstrated that the conjugation of a dG6 run into the 3' terminus of phosphodiester CpG ODNs was crucial for their ability to generate Th1 immunity in vivo. Thus, the conjugation of a dG6 run into phosphodiester CpG ODNs would be an alternative way to optimize their immunostimulatory potentials in vitro and in vivo.

Development of a modified three-stage methane production process using food wastes

A modified three-stage system was developed for the rapid production of methane from food wastes. The primary stage was a semianaerobic hydrolysis/acidogenic system, in which approx 4100 mg/L of volatile fatty acids (VFAs) was produced at a hydraulic retention time (HRT) of 2 d. The operation temperature and pH were 30 degrees C and 5.0-5.5, respectively. The non-degraded materials were removed through a hole at the bottom of the reactor. The secondary stage was an anaerobic acidogenic system equipped with an upflow anaerobic sludge blanket (UASB) type of fermentor. VFA was accumulated up to 6100 mg/L by the addition of Clostridium butyricum to the reactor at an HRT of 2 d. The optimum temperature and pH range were 35 degrees C and 5.0-5.5, respectively. The tertiary methanogenic stage produced CH4 and CO2 from the VFA in the UASB reactor. Methane content was 72% of the total gas volume, and the yield was 0.45-0.50 m3/kg of volatile solids at an HRT of 12 d. The operation temperature and pH were 41 degrees C and 7.6-7.9, respectively. The three-stage process exhibited an unusually high total chemical oxygen demand reduction rate up to 95%. Total nitrogen decreased to 96% and < 10 mg/L of total phosphorus remained in the final effluent.

Correlation between monocyte and T-lymphocyte activation markers in patients with acute coronary syndrome

Evidence suggesting the involvement of activated monocytes and T-lymphocytes in the acute phase of coronary artery disease (CAD) has been increasing. But a detailed analysis of a correlation between monocyte and T-lymphocyte activation markers in CAD has not yet been done. We analyzed plasma C-reactive protein (CRP) levels and the expression levels of CD14 and CD11b on monocytes and the percentage of HLA-DR T-lymphocytes in 25 patients with acute coronary syndrome (ACS), 12 stable angina (SA) patients, and 23 control subjects using flow-cytometry. The expression of CD14 by monocytes was increased significantly in ACS patients (activation index 38.7 +/- 2.5, mean +/- SEM) in comparison to the control subjects (8.0 +/- 1.9) and the SA patients (16.9 +/- 3.9) (p < 0.001 and p < 0.01, respectively). The expression of CD11b by monocytes of ACS patients (4.6 +/- 0.6) was also increased significantly in comparison to control subjects (2.2 +/- 0.1) and the SA patients (2.2 +/- 0.3) (p < 0.001 for both). Also, a significantly higher percentage of HLA-DR positive T-lymphocytes (19.2 +/- 1.8 vs 13.5 +/- 1.2%, p < 0.05) was observed among ACS patients in comparison to control subjects. Significant increases in plasma CRP levels were also detected in ACS patients. Furthermore, there were statistically significant correlations among these activation markers. These results indicate that activation of inflammatory cells may play a role in the pathogenesis of ACS. The correlation between the activation status of monocytes and T-lymphocytes indicates that the activation of these immune cells is linked in such a way that activation of one type of cell may lead to the activation of another type of cell.

Diagnosis of vertebral metastasis, epidural metastasis, and malignant spinal cord compression: are T(1)-weighted sagittal images sufficient?

The objective of this study was to determine whether T(1)-weighted sagittal images alone are adequate in the diagnosis of vertebral metastasis, epidural metastasis, and malignant spinal cord compression. Ninety-four complete magnetic resonance (MR) studies of the spinal column (a complete study consisting of T(1)-weighted sagittal images, T(2)-weighted sagittal images, and T(1)- and/or T(2)-weighted axial images) and 94 T(1)-weighted sagittal images alone (a subset of the complete studies) from 57 consecutive cancer patients over the last 2 years with clinically suspected cord compression were blindly and independently evaluated by four radiologists. The complete MR studies were used as the standard. Overall, the sensitivity of T(1)-weighted sagittal images alone to vertebral metastasis (87%) was statistically greater than cord compression (70%) (p = 0.05), and statistically greater than epidural metastasis (46%) (p </= 0.02). The specificity for cord compression (97%) was greater than the specificity for epidural metastasis (89%) (p = 0.03), and greater than the specificity for vertebral metastasis (83%) (p </= 0.02). There was a strong trend for better detection of cord compression overall and better detection of vertebral metastasis in the cervical spine by the most experienced radiologist. Complete studies of the spine are necessary in the diagnosis of vertebral metastasis, epidural metastasis, and cord compression, particularly with less experienced radiologists.

Mutation analysis of Korean patients with citrullinemia

Citrullinemia is an autosomal recessive disease due to the mutations in the argininosuccinate synthetase (ASS) gene. Mutation analysis was performed on three Korean patients with citrullinemia. All of the three patients had the splicing mutation previously reported as IVS6-2A>G mutation. Two had Gly324Ser mutation and the other patient had a 67-bp insertion mutation in exon 15. The IVS6-2A>G mutation was reported to be found frequently in Japanese patients with citrullinemia, but Caucasian patients showed the extreme mutational heterogeneity. Although a limited number of Korean patients were studied, the IVS6-2A>G mutation appears to be one of the most frequent mutant alleles in Korean patients with citrullinemia. The Gly324Ser mutation identified in two patients also suggests the possible high frequency of this mutation in Korean patients as well.

In Planta visual monitoring of green fluorescent protein in transgenic rice plants

The green fluorescent protein (GFP) from the jellyfish Aequorea victoria is a widely used reporter that can be directly visualized in the living cells in both animals and plants. We inserted a synthetic gene (sgfp) encoding a modified form of the GFP into expression vector, Act1-sgfp for the direct expression of GFP which is easily detectable in rice plants. Green fluorescence emitted from GFP could be visualized in calli, dry seeds, roots and seedlings with green shoots of transgenic rice plants. In our visualization system with a charge-coupled device camera, band-pass filters and a light source, the presence of red chlorophyll autofluorescence from chloroplasts did not alter the green fluorescence of GFP. These results demonstrate that GFP could be used as a non-destructive visual selection marker for examining gene expression in transformed calli, dry seeds and young plants.

Analysis of expressed sequence tags from Brassica rapa L. ssp. pekinensis

Non-redundant expressed sequence tags (ESTs) were generated from six different organs at various developmental stages of Chinese cabbage, Brassica rapa L. ssp. pekinensis. Of the 1,295 ESTs, 915 (71%) showed significantly high homology in nucleotide or deduced amino acid sequences with other sequences deposited in databases, while 380 did not show similarity to any sequences. Briefly, 598 ESTs matched with proteins of identified biological function, 177 with hypothetical proteins or non-annotated Arabidopsis genome sequences, and 140 with other ESTs. About 82% of the top-scored matching sequences were from Arabidopsis or Brassica, but overall 558 (43%) ESTs matched with Arabidopsis ESTs at the nucleotide sequence level. This observation strongly supports the idea that gene-expression profiles of Chinese cabbage differ from that of Arabidopsis, despite their genome structures being similar to each other. Moreover, sequence analyses of 21 Brassica ESTs revealed that their primary structure is different from those of corresponding annotated sequences of Arabidopsis genes. Our data suggest that direct prediction of Brassica gene expression pattern based on the information from Arabidopsis genome research has some limitations. Thus, information obtained from the Brassica EST study is useful not only for understanding of unique developmental processes of the plant, but also for the study of Arabidopsis genome structure.

Increased energy expenditure, decreased adiposity, and tissue-specific insulin sensitivity in protein-tyrosine phosphatase 1B-deficient mice

Protein-tyrosine phosphatase 1B (PTP-1B) is a major protein-tyrosine phosphatase that has been implicated in the regulation of insulin action, as well as in other signal transduction pathways. To investigate the role of PTP-1B in vivo, we generated homozygotic PTP-1B-null mice by targeted gene disruption. PTP-1B-deficient mice have remarkably low adiposity and are protected from diet-induced obesity. Decreased adiposity is due to a marked reduction in fat cell mass without a decrease in adipocyte number. Leanness in PTP-1B-deficient mice is accompanied by increased basal metabolic rate and total energy expenditure, without marked alteration of uncoupling protein mRNA expression. In addition, insulin-stimulated whole-body glucose disposal is enhanced significantly in PTP-1B-deficient animals, as shown by hyperinsulinemic-euglycemic clamp studies. Remarkably, increased insulin sensitivity in PTP-1B-deficient mice is tissue specific, as insulin-stimulated glucose uptake is elevated in skeletal muscle, whereas adipose tissue is unaffected. Our results identify PTP-1B as a major regulator of energy balance, insulin sensitivity, and body fat stores in vivo.

Test-bolus injection for optimization of arterial phase imaging during contrast-enhanced hepatic MR imaging

Contrast enhancement during the dynamic MR imaging is important for the detection and characterization of focal liver lesions. The purpose of this study was to determine whether or not a timing examination with a injection of a 1.0-mL bolus of gadopentetate dimeglumine into the antecubital vein followed by rapid dynamic scanning and measurement of signal intensity of the aorta could help to obtain proper arterial-dominant phase images for the characterization of focal hepatic lesions during subsequent multiphase dynamic MR imaging. The imaging delay to acquisition of the first gadolinium-enhanced image for multiphase dynamic MR imaging was set to equal the time to peak aortic enhancement during the test examination. The first contrast-enhanced images of 80 patients with 160 focal liver lesions (hepatocellular carcinoma, n = 79; cavernous hemangioma, n = 51; metastatic tumor, n = 30) were then retrospectively reviewed. Peak aortic enhancement occurred between 10 and 28 seconds (mean, 16.5 seconds +/- 3.1) after starting the infusion of contrast material in 80 patients during the test-examination. Depending on the findings of intrahepatic vascular enhancement on the full-scale dynamic images, hepatic arterial phase (n = 11, 14%) or sinusoid phase (n = 65, 81%) imaging was obtained during the first gadolinium-enhanced acquisition in 76 (95%) of 80 patients. Three different lesions were well characterized and easily distinguished from each other (p < .0001) on the first-phase images depending on their enhancement pattern. In the majority of patients, timing examination with test-bolus injection was helpful in obtaining qualified images for the characterization of various focal lesions.

Cellular distribution of isozymes of protein kinase C in septal olfactory epithelium of mice

To determine the presence of protein kinase C (PKC) isozymes in the septal olfactory epithelium of mice (mSOE), western blotting and immunohistochemistry were performed using antibodies against PKC isozymes. With the exception of PKC-betaI, all of the PKC isozymes were detected in the whole lysate of septal tissue layer and apparent molecular weights for each isoform were found. PKC-alpha, PKC-gamma and PKC-epsilon were detected in the olfactory glandular cells of the lamina propria, and PKC-betaI and PKC-betaII were located in the microvillar cells. Neither novel PKC nor atypical PKC was detected in olfactory glandular cells or microvillar cells, except for PKC-epsilon. PKC-lambda was localized in the mucous layer of the mSOE. Meanwhile, PKC-delta and PKC-xi were distributed in the receptor cells in the mSOE. These data demonstrate the isoform-specific expression of PKC in mSOE and suggest a role for the novel and atypical types of PKC in olfactory transduction.

Cloning and characterization of the 5'-flanking region for the mouse phospholipase C-delta1 gene

To date, little is known about the molecular mechanisms controlling the regulation of phospholipase C-delta1 (PLC-delta1) gene expression. To understand the mechanisms responsible for the regulation of PLC-delta1 gene expression, the 5'-flanking region of the mouse PLC-delta1 gene was isolated from a mouse genomic DNA library. Primer extension analysis revealed that there is a single transcriptional start site located at 127 bases upstream from the translation start codon in the mouse PLC-delta1 gene. DNA sequence analysis showed that the sequence around the transcriptional start site is very GC-rich and has no TATA or CAAT boxes. Transient expression of a luciferase reporter gene under the control of serially deleted 5'-flanking sequences revealed that the 160-base-pair region from -622 to -462 upstream of the transcriptional start site includes a positive cis-acting element(s) for the efficient expression of the PLC-delta1 gene. Gel retardation analysis suggests that multiple transcription factors bind to separate sites on the promoter region. Based on these results, our study suggests that the minimal essential region located at -622 to +70 is fully sufficient to confer high-level transcriptional activity and contains high-affinity binding elements for multiple transcription factors.