Involvement of RFX1 protein in the regulation of the human proliferating cell nuclear antigen promoter

The proliferating cell nuclear antigen (PCNA) is an essential eukaryotic DNA replication factor that is transcriptionally regulated by the adenovirus oncoprotein E1A 243R. Inducibility of the human PCNA promoter by E1A 243R is conferred by the cis-acting PCNA E1A-responsive element (PERE), which associates with the ATF-1, cAMP response element-binding protein (CREB), and RFX1 transcription factors and is modulated by cellular proteins such as the coactivator CREB-binding protein (CBP) and tumor suppressor p107 (Labrie, C., Lee, B. H., and Mathews, M. B. (1995) Nucleic Acids Res. 23, 3732-3741; Lee, B. H., and Mathews, M. B. (1997) Proc. Natl. Acad. Sci. U. S. A. 94, 4481-4486; Lee, B. H., Liu, M., and Mathews, M. B. (1998) J. Virol. 72, 1138-1145). RFX1 also forms a complex with sequences in the PCNA promoter of mouse and rat that share homology with the RFX1 consensus site. To explore the role of RFX1 in regulating the PCNA promoter, we examined the effects of mutations in the human PERE on RFX1 binding and gene expression. Mutations within the RFX1 consensus binding site reduced RFX1 binding, whereas mutations upstream of the site, or on its border, increased RFX1 binding. These mutations also affected the transcriptional activity of PCNA-chloramphenicol acetyltransferase reporter constructs in transient expression assays. The relative transcriptional activity of mutant PCNA promoters, both in the presence and absence of E1A 243R, was inversely related to their ability to complex with RFX1. These findings suggest that the binding of RFX1 is influenced by sequences outside its consensus binding site and that this transcription factor plays an inhibitory role in the regulation of PCNA gene expression.

In vivo pharmacologic profile of SK-1080, an orally active nonpeptide AT1-receptor antagonist

The pharmacologic profile of SK-1080, a newly synthesized AT1-receptor antagonist, was evaluated in conscious normotensive rats, conscious renally (RHRs) and spontaneously (SHRs) hypertensive rats, and conscious furosemide-treated beagle dogs. In angiotensin II-challenged normotensive rats, orally administered SK-1080 had no agonistic effect and dose-dependently inhibited the pressor response to angiotensin II with a slightly weaker potency (ID50: 1.12 and 0.47 mg/kg, respectively), but with a more rapid onset of action than losartan (time to Emax, 30 min and 6 h, respectively). In RHRs, orally given SK-1080 produced a dose-dependent and long-lasting (>24 h) antihypertensive effect with a potency similar to that of losartan (ED20, 5.06 and 3.36 mg/kg, respectively). Intravenously administered SK-1080 exerted a very highly potent antihypertensive effect (ED20, 0.06 mg/kg), thus indicating a poor oral bioavailability in rats. On repeated dosing for 21 days in SHRs, SK-1080 significantly reduced blood pressure without inducing tachycardia and tolerance throughout the dosing period. On repeated dosing, the antihypertensive effect gradually increased from days 1 to 7 (Emax on day 7, 15.0 and 19.7% at 10 and 30 mg/kg, respectively) and remained at a significant level on days 14 and 21. In furosemide-treated dogs, orally given SK-1080 produced a dose-dependent and long-lasting (>8 h) antihypertensive effect with a rapid onset of action (time to Emax, 1-1.5 h) and 10-fold greater potency than losartan (ED20, 0.72 and 8.13 mg/kg, respectively). In furosemide-treated dogs, SK-1080 showed a good oral bioavailability, unlike that in RHRs. These results suggest that SK-1080 is a potent, orally active AT1-receptor antagonist useful for the treatment of hypertension.

Characterization of angiotensin II antagonism displayed by SK-1080, a novel nonpeptide AT1-receptor antagonist

The pharmacologic profile of SK-1080, a nonpeptide AT1-selective angiotensin-receptor antagonist, was investigated by receptor-binding studies, functional in vitro assays with rabbit and rat aorta, and in vivo experiments in pithed rats. SK-1080 inhibited the specific binding of [125I]-[Sar1, Ile8]-angiotensin II to human recombinant AT1 receptor with a 12-fold greater potency than losartan [median inhibitory concentration (IC50): 1.01 and 12.3 nM, respectively], but it did not inhibit the binding of [125I]-CGP 42112A to human recombinant AT2 receptor (IC50: >10 microM for both). The Hill coefficient for the competition curve of SK-1080 against AT1 receptor was not significantly different from unity (0.96). Scatchard analysis showed that SK-1080 interacted with human recombinant AT1 receptor in a competitive manner, as with losartan. In functional studies with rat and rabbit aorta, SK-1080 competitively inhibited the contractile response to angiotensin II (pKB values: 9.97 and 9.51, respectively) with 15-25% decrease in the maximal contractile responses, unlike losartan, which showed competitive antagonism without any change in the maximal contractile responses to angiotensin II (pA2 values, 8.02 and 7.59, respectively). In pithed rats, SK-1080 (i.v.) induced a nonparallel right shift in the dose-pressor response curve to angiotensin II (ID50, 0.07 mg/kg) with a dose-dependent reduction in the maximal responses; this antagonistic effect was approximately 25 times more potent than losartan (ID50, 1.74 mg/kg), which showed competitive antagonism. SK-1080 did not alter the responses induced by other agonists such as norepinephrine, KCI, and vasopressin in isolated rabbit aorta and pithed rats. These results suggest that SK-1080 is a highly potent AT1-selective angiotensin II-receptor antagonist with a mode of insurmountable antagonism.

Proposing sequences for peptides derived from whey fermentation with potential bioactive sites

In fed-batch fermentation by Kluyveromyces marxianus var. marxianus, whey-soluble proteins were converted into oligopeptides. To assess whether bioactive peptides could be produced during whey fermentation, K. marxianus was cultured in batch in deproteinized media containing 5 or 15% (wt/vol) dehydrated whey for 20 h and then was in fed-batch mode for 50 h. After harvesting the biomass (25,000 x g, 15 min), at 6-h intervals, the wort was analyzed to determine protein consumption and oligopeptide production by HPLC. The proteins in the wort showed an oscillatory degradation with a constant increase in the production of oligopeptides. Four major peaks were collected and were analyzed by API mass spectroscopy. Sequences of fermented peptides were compared with sequences of known bioactive peptides. On the basis of their molecular weights, two amino acid sequences were proposed. The presence of sites containing the peptide sequence of beta-lactorphin (YLLF) suggests that these oligopeptides may have antihypertensive properties.

The nuclei innervating digastric muscle do not project to the hypoglossal nucleus in the rat

We employed the retrograde neural tracing method using the pseudorabies virus bartha strain (PRV-Ba) to investigate the projection from accessory trigeminal nucleus (Acc5) or accessary facial nucleus (Acc7) to hypoglossal nucleus (HP). After injection of PRV-Ba into the bellies of the digastric muscle, the PRV-Ba containing neurones were observed in Acc5 of the cranial belly injected rats and Acc7 of caudal belly injected rats ipsilaterally, but not in HP. These results suggest that Acc5 and Acc7 may not project to HP and that movements of the digastric muscle are not related to cooperation with tongue movements during mastication.

Manganese-containing superoxide dismutase and its gene from Candida albicans

Mitochondrial manganese-containing superoxide dismutase was purified around 112-fold with an overall yield of 1.1% to apparent electrophoretic homogeneity from the dimorphic pathogenic fungus, Candida albicans. The molecular mass of the native enzyme was 106 kDa and the enzyme was composed of four identical subunits with a molecular mass of 26 kDa. The enzyme was not sensitive to either cyanide or hydrogen peroxide. The N-terminal amino acid sequence alignments (up to the 18th residue) showed that the enzyme has high similarity to the other eukaryotic manganese-containing superoxide dismutases. The gene sod2 encoding manganese-containing superoxide dismutase has been cloned using a product obtained from polymerase chain reaction. Sequence analysis of the sod2 predicted a manganese-containing superoxide dismutase that contains 234 amino acid residues with a molecular mass of 26173 Da, and displayed 57% sequence identity to the homologue of Saccharomyces cerevisiae. The deduced N-terminal 34 amino acid residues may serve as a signal peptide for mitochondrial translocation. Several regulatory elements such as stress responsive element and haem activator protein 2/3/4/5 complex binding sites were identified in the promoter region of sod2. Northern analysis with a probe derived from the cloned sod2 revealed a 0.94-kb band, which corresponds approximately to the expected size of mRNA deduced from sod2.

Preventive effects of a mixed disulphide from dithiocarbamate and N-acetylcysteine on the genotoxicity of N-nitrosodiethylamine

A mixed disulphide model compound, S-(N,N-diethyldithiocarbamoyl)-N-acetylcysteine (AC-DDTC), prepared from diethyldithiocarbamate and N-acetylcysteine, was investigated for protective effects against the genotoxicity of the environmental carcinogen N-nitrosodiethylamine (NDEA). AC-DDTC was found to be a potent inhibitor of genotoxicity induced by NDEA. The mutagenicity of NDEA to Salmonella typhimurium was inhibited by 70% at 3.2 micromol AC-DDTC per plate and the effect was dose-dependent. In the chromosome aberration assay, NDEA elicited a significant increase in the number of aberrant cells. Pretreatment with AC-DDTC suppressed the chromosome-damaging effect of NDEA. The micronucleus-inducing capacity of NDEA was reduced by 32% by treatment with AC-DDTC at 1.5 mmol kg(-1). These results suggest that AC-DDTC might have a role to play in reducing the risk of cancer induced by NDEA.

Investigation of Coordinational Properties of Europium(III) Complexes with Picolinic Acid Using Eu(III) Excitation Spectroscopy

The 7F0 --> 5D0 excitation spectra of Eu(III) complexed with picolinic acid were investigated using Eu(III) excitation spectroscopy. Six overlapping peaks are seen in the excitation spectra, indicating the formation of six species. The structures of the six species are proposed here and described in terms of both coordination by carboxylate and N-chelation. Copyright 1999 Academic Press.

Regulation of fibronectin gene expression by cyclic AMP and phorbol myristate acetate in HT-1080 human fibrosarcoma cells

We studied the regulation of fibronectin (FN) gene expression by cAMP and phorbol-12-myristate-13-acetate (PMA) in HT-1080 human fibrosarcoma cells. Dibutyryl cAMP increased FN synthesis and mRNA levels, while PMA inhibited the cAMP-induced FN synthesis. In transient transfection assays, cAMP increased FN promoter activity, while PMA paradoxically enhanced the cAMP-induced promoter activity. Stable transfection experiments, however, showed that neither cAMP or PMA alone nor together affected FN promoter activity. These results suggest that PMA antagonizes the cAMP-induced FN gene expression and that both the action of cAMP and the inhibition of its action by PMA may occur at the posttranscriptional level in HT-1080 cells.

D-arabinose dehydrogenase and its gene from Saccharomyces cerevisiae

D-Arabinose dehydrogenase was purified 843-fold from the cytosolic fraction of Saccharomyces cerevisiae with a recovery of 9%. The purified enzyme gave two bands with a molecular mass of 40 and 39 kDa on SDS-PAGE. The native enzyme had a molecular mass of 74 kDa as estimated by Sephacryl S-200 chromatography. Therefore, this enzyme was considered to be a heterodimer. The purified enzyme exhibited maximum activity at pH 10.0 and around 30 degrees C. The enzyme catalysed the oxidation of D-arabinose, L-xylose, L-fucose and L-galactose in the presence of NADP+. The apparent Km values at pH 10.0 with 50 microM NADP+ for D-arabinose, L-xylose, L-fucose, and L-galactose were 161, 24, 98 and 180 mM, respectively. The pH profile of Vmax and kcat/Km showed one ionisable groups around pH 8.3. D-Erythroascorbic acid was formed in vitro from D-arabinose by D-arabinose dehydrogenase and D-arabinono-1,4-lactone oxidase. The N-terminal amino acid sequence of the heavy subunit was Ser-Thr-Glu-Asn-Ile-Val-Glu-Asn-Met-Leu-His-Pro-Lys-Thr-. The N-terminus of the light subunit was blocked. The obtained peptide sequence was identical to the translational product of an unknown open reading frame, YBR149W, in chromosome II of S. cerevisiae. When compared with the translational product of this open reading frame, the peptide sequence was identical to the amino acid sequences of residues 7 to 20. The first six amino acids of this open reading frame were lost in protein sequence, which may be modified post-translationally. The heavy subunit was composed of 344 amino acid residues and its deduced amino acid sequence contained the motifs I, II, and III of aldo-keto reductase and also leucine zipper motif. This enzyme is the first heterodimeric protein of aldo-keto reductase family. In the deletion mutant of this gene, D-arabinose dehydrogenase activity and D-erythroascorbic acid were not detected.

Anthelmintic beta-hydroxyketoamides (BKAs)

We have prepared several anthelmintic coumarins based on the beta-hydroxyketoamide (BKA) template and have shown that this template remains valid over a wide range of changes to the coumarin moiety allowing for the inclusion of carbocyclic, bicyclic, and heterocyclic rings.

C24 and C25 substituted marcfortine A derivatives

The dioxepinoindole ring found in marcfortine A (1) is unique among natural products. In order to determine the importance of the substitution pattern of the C24-C25 olefin, we synthesized a variety of analogs at these positions. With the exception of compound 5, none of these compounds exhibited any anthelmintic activity.

Upregulation of a histone-like protein in dormant Mycobacterium smegmatis

The aerobic saprophyte Mycobacterium smegmatis, like its pathogenic counterpart M. tuberculosis, has the ability to adapt to anaerobiosis by shifting down to a dormant state. Here, we report the identification and molecular genetic characterisation of the first dormancy-induced protein in M. smegmatis. Comparative SDS-polyacrylamide gel electrophoresis of protein extracts of aerobically growing and dormant anaerobic M. smegmatis cultures revealed the upregulation of a 27-kDa protein in the dormant state. Peptide sequencing showed that the induced protein is a homologue of the histone-like protein H1p, predicted by the M. tuberculosis genome project. The corresponding hlp gene was cloned from M. smegmatis and sequenced. Disruption of the hlp gene eliminated the histone-like protein but did not affect the viability of the dormant culture.

In vitro chromosome aberration assay using human bronchial epithelial cells

The determination of chromosome aberrations (CA) in Chinese hamster lung fibroblast (CHL) cells was compared with that in normal human bronchial epithelial (BEAS-2B) cells, which upon adenovirus infection were reported to possess carcinogen metabolizing capacities similar to polycyclic aromatic hydrocarbons. CHL and BEAS-2B cells were treated with increasing concentrations of benzo[a]pyrene (BaP) or N-nitrosodiethylamine (NDEA). In BEAS-2B cells, BaP, at a concentration of 50 microg/ml, produced a significant increase in the CA frequency, while NDEA did not markedly alter the number of aberrations in the absence of S9 mixture. The CHL cells exposed to BaP and NDEA in the presence of S9 mixture responded as anticipated with a 30% and 14% frequency of CA observed in the BaP (50 microg/ml) and NDEA (1000 microg/ml) treated cells, respectively. The results of this study show that the CA assay using human cell line with intrinsic metabolic activation system, such as BEAS-2B cells, may be a useful model for predicting human clastogens and carcinogens.

D-Erythroascorbic acid is an important antioxidant molecule in Saccharomyces cerevisiae

D-Arabinono-1,4-lactone oxidase catalysing the final step of D-erythroascorbic acid biosynthesis was purified from the mitochondrial fraction of Saccharomyces cerevisiae. Based on the amino acid sequence analysis of the enzyme, an unknown open reading frame (ORF), YML086C, was identified as the ALO1 gene encoding the enzyme. The ORF of ALO1 encoded a polypeptide consisting of 526 amino acids with a calculated molecular mass of 59493Da. The deduced amino acid sequence of the enzyme shared 32% and 21% identity with that of L-gulono-1,4-lactone oxidase from rat and L-galactono-1,4-lactone dehydrogenase from cauliflower, respectively, and contained a putative transmembrane segment and a covalent FAD binding site. Blot hybridization analyses showed that a single copy of the gene was present in the yeast genome and that mRNA of the ALO1 gene was 1.8kb in size. In the alo1 mutants, D-erythroascorbic acid and the activity of D-arabinono-1,4-lactone oxidase could not be detected. The intracellular concentration of D-erythroascorbic acid and the enzyme activity increased up to 6.9-fold and 7.3-fold, respectively, in the transformant cells carrying ALO1 in multicopy plasmid. The alo1 mutants showed increased sensitivity towards oxidative stress, but overexpression of ALO1 made the cells more resistant to oxidative stress.

Distribution of tachykinin-related neuropeptide in the developing central nervous system of the moth spodoptera litura

Neuropeptides with similarities to vertebrate tachykinins, designated tachykinin-related peptides (TRPs), have been identified in several insect species. In this investigation we have utilized an antiserum raised to one of the locust TRPs, locustatachykinin-I (LomTK-I), to determine the distribution pattern of LomTK-like immunoreactive (LTKLI) neurons in the developing nervous system of the moth Spodoptera litura. A number of LTKLI neurons could be followed from the larval to the adult nervous system: a set of median neurosecretory cells (MNCs) in the brain, a pair of brain descending neurons and a few sets on neurons in the ventral nerve cord. The distribution of LTKLI neurons in the adult brain is very similar to that seen in other insect species with prominent arborizations in the central body, antennal lobes, mushroom body calyces, optic lobe neuropils and other distinct neuropil areas in the protocerebrum and tritocerebrum. A new finding is the presence of LTKLI neurosecretory cells with axon terminals in the anterior aorta and corpora cardiaca, suggesting for the first time a neurohormonal role of tachykinin-related peptide(s) in insects. During postembryonic development the number of LTKLI neurons in the ventral nerve cord decreases somewhat, whereas the number increases in the brain. Thus the functional roles of TRPs may change to some extent during development.

Bending sensitivity of in-series long-period fiber gratings

The interference fringes formed in a long-period fiber grating pair are sensitive to the loss in the cladding mode, which can be induced by bending or by coating on the fiber. Assuming that there is no loss and that both gratings are identical, the interference fringes are shown to have 100% contrast when each grating has 50% transmissivity. By contrast, if the cladding mode is absorbed or scattered the fringe contrast is shown to be degraded. The spectral behaviors of a long-period fiber grating pair with loss is analyzed by the coupled-mode theory and is compared with experimental results.

Expression of gonadotropin-releasing hormone (GnRH) and GnRH receptor mRNA in prostate cancer cells and effect of GnRH on the proliferation of prostate cancer cells

The purpose of this study was to determine the production of gonadotropin-releasing hormone (GnRH), the co-occurrence of GnRH receptors in prostate cancer cells, and the effect of GnRH on prostate cancer cell proliferation. Four human prostate cancer cell lines were studied. LNCaP is an androgen sensitive prostate cancer cell line, DU-145 and PC-3 are androgen resistant, and TSU-Pr1 is uncharacterized. The expression of GnRH and GnRH receptor mRNAs were assessed by in situ hybridization and the effect of exogenous GnRH on proliferation of prostate cancer cells was measured by thymidine incorporation assay. GnRH mRNA expression, determined by in situ hybridization, was found in 83.48% of the LNCaP, 89.7% of the TSU-Pr1, 86.2% of the PC-3 and 95.3% of the DU-145. Signals of GnRH receptor mRNA were detected in more than 95% of the cells of all four cell lines. The proliferation of the prostate cancer cells grown in media supplemented with peptide hormone lacking charcoal-stripped serum was significantly (P < 0.05) suppressed. No significant effect of GnRH on the proliferation of all four prostate cancer cells was observed. In summary, prostate cancer cells produced GnRH and its receptors, and exogenous GnRH treatment did not affect the prostate cancer cell proliferation. The existence of GnRH and GnRH receptor mRNA in the same cell suggests that the role of GnRH produced by prostate cancer cells would be autocrine.

A simple program to calculate codon bias index

A computer program (PCBI) was developed to quickly calculate codon bias index (CBI). PCBI can analyze a gene containing introns. The 22 preferred codons defined from Saccharomyces cerevisiae were used in PCBI as the standard to measure the CBI values. However, users can modify the preferred codons to suit each organism. The data PCBI provides include DNA sequence of open reading frame without introns, amino acid sequence of gene product, a table of amino acid composition, a table of codon usage and (G + C) content, parameters for calculating CBI, and the value of CBI. PCBI runs on a DOS or Windows environment, but results can be saved in ASCII text format.

Antihypertensive effects of the novel potassium channel activator SKP-450 and its major metabolites in rats

Antihypertensive effects of SKP-450 (KR-30450, CAS 172489-10-0, (-)-(2R)-2"-(1",3"-dioxolan-2-yl)-2-2methyl-4-(2'-oxopyrr olidin-1-yl)-6- nitro-2H-1-benzopyran), a newly synthesized potassium channel activator, and its major metabolites SKP-818 ((-)-(2R)-2"-hydroxymethyl-2-methyl-4-(2'-oxopyrrolidin-1-yl)-6-ni tro- 2H-1-benzopyran) and SKP-310 ((-)-(2R)-2"-carboxy-2-methyl-4-(2'-oxopyrrolidin-1-yl)-6-nitro-2H -1- benzopyran) were evaluated in freely moving spontaneously hypertensive (SHR), renally hypertenisve (RHR), DOCA/salt-induced hypertensive (DHR) and normotensive rats (NR). The effects of long-term treatment with SKP-450 on blood pressure and arterial reactivity were also studied in SHR. SKP-450 (3-300 micrograms/kg, p.o.) and SKP-818 (3-100 micrograms/kg, i.v.) dose-dependently decreased mean arterial pressure (MAP) (potency order: SKP-450, RHR > SHR = DHR > NR; SKP-818, DHR = SHR = RHR > NR); however, SKP-310 did not influence MAP. Compared with lemakalim, SKP-450 was 2 to 5 fold more potent in SHR and NR, and equipotent in RHR and DHR. Repeatedly administration of SKP-450 to SHR over 21 days (10 and 30 micrograms/kg, p.o., once a day), had no significant effect on the degree and pattern of its antihypertensive effects and on the reactivity of isolated aorta to various vasoconstrictors and vasodilators. These results suggest that SKP-450 is a potent peripheral vasodilator acting without the development of tolerance and the alteration in vascular reactivity. SKP-818 and SKP-310 may play a role as an active metabolite and inactive intermediary, respectively.

The distribution of calcitonin gene-related peptide in gastric vagal circuit of rats

In the present study, we performed the retrograde tracing method using the neurotropic pseudorabies virus bartha strain (PRV-Ba) and immunohistochemistry against CGRP, to identify whether CGRP exists in the gastric monosynaptic vagal circuit between dorsal motor nucleus of vagus nerve (DMV) and nucleus tractus solitarius (NTS). At the results, PRV immunoreactive neurons were found in both DMV and NTS. However, CGRP-immunoreactive cells were present only in NTS, which contained no double-labeled neurons for PRV and CGRP. These results suggest that CGRP may not have a neuronal function in gastric vagal circuit of rat.

Production of bioingredients from Kluyveromyces marxianus grown on whey: an alternative

Whey waste is a major problem for the dairy industry. Finding alternative means to reduce its pollution potential and produce high value-added bioingredients has been attempted by many researchers. Kluyveromyces marxianus var. marxianus is a dairy yeast that produces beta-galactosidase, allowing for whey fermentation. Also, K. marxianus has been proposed as a source of: (1) oligonucleotides, used as flavor enhancers in food products; (2) oligosaccharides, used as prebiotics to stimulate the growth of Bifidobacterium sp. in the animal and human intestines; and (3) oligopeptides, immunostimulators added to dairy products that are released in the wort after whey protein proteolysis. Fed-batch fermentation can be used as an alternative process to avoid increases in lactose concentration and prevent the catabolite repression of the respiratory enzyme synthesis during aerobic fermentation, thus allowing for high biomass yields. The relevance of these factors on yeast fermentation of whey is summarized in this critical review.

Evolutionary origin of two genes for chloroplast small heat shock protein of tobacco

Two different cDNA clones for the chloroplast small heat shock protein (smHSP) were isolated from tobacco (Nicotiana tabacum cv. Petit Havana SR1). One of the cDNAs (type I) has a full-length open reading frame (ORF) of the smHSP of 26.6 kDa. By contrast, the other one (type II) contains an additional nucleotide that causes the frame shift inside a putative ORF for the smHSP. If this nucleotide is neglected, type II cDNA encodes the smHSP that is 89% identical to that encoded by type I cDNA. Southern blot and polymerase chain reaction (PCR) analyses with genomic DNA indicated that tobacco has two different smHSP genes while two ancestors of tobacco, N. sylvestris and N. tomentosiformis, have a single gene that each corresponds to one of the two genes of tobacco. It was also found that one of the tobacco genes has an ORF for the smHSP disrupted by nucleotide insertion in the same way as type II cDNA, while both ancestor genes have a functional ORF. These results suggest that the two smHSP genes of tobacco had been derived from the two ancestor species, and that one of the two genes had been disrupted by nucleotide insertion during the course of the evolution of tobacco. Northern blot and reverse transcription (RT)-PCR analyses demonstrated that both the tobacco genes are expressed upon heat stress, exhibiting different dependences on temperature.

In vitro antigenotoxic activity of novel ginseng saponin metabolites formed by intestinal bacteria

Ginseng saponin metabolites produced by human intestinal bacteria were evaluated for antigenotoxic properties by testing their effects on benzo[a]pyrene (B[a]P)-induced mutagenicity and clastogenicity. They include 20-O-(beta-D-glucopyranosyl)-20(S)-protopanaxadiol (IH-901), 20-O-(alpha-D-arabinopyranosyl(1-->6)-beta-D-glucopyranosyl]- 20(S)-protopanaxadiol (IH-902) and 20-O-[alpha-D-arabinofuranosyl(1-->6)-beta-D-glucopyranosyl]-20(S)- protopanaxadiol (IH-903). IH-901, IH-902 and IH-903 inhibited the mutagenicity of B[a]P in a dose-dependent manner. In the chromosome aberration assay, IH-901 and IH-903 reduced the frequency of chromosome aberration induced by B[a]P. These results suggest that the ginseng saponin metabolites tested in the present study have potential as chemopreventive agents.

Obliteration of the pulmonary vein in lung cancer: significance in assessing local extent with CT

PURPOSE

The purpose of this study was to evaluate the significance of obliteration of the pulmonary vein in assessing local extent of lung cancer with CT, particularly in regard to intrapericardial extension of tumor through the vein.

METHOD

Preoperative CT scans of 325 patients, who underwent thoracotomy for primary lung cancer, were reviewed. Among them, CT scans of 19 patients showed obliteration of the pulmonary vein up to its entrance into the left atrium, without filling defect in the left atrium. Surgical records of these patients were then reviewed to investigate the extent of tumor growth through the pulmonary vein, with particular emphasis on intrapericardial extension.

RESULTS

The surgical records revealed extension of tumor through the pulmonary vein beyond the pericardial reflection in 14 or 19 patients. In 10 patients showing obliteration of either the left of the right superior pulmonary vein, all tumors extended beyond the pericardial reflection (100%). Intrapericardial extension occurred in four of nine patients showing obliteration of either the left or the right inferior pulmonary vein (44%). The difference was statistically significant (p < 0.05).

CONCLUSION

When assessing local extent of lung cancer with CT, obliteration of the superior pulmonary vein is a highly suggestive finding for intrapericardial extension of tumor through the pulmonary vein. On the contrary, obliteration of the inferior pulmonary vein is believed to be a less reliable finding for intrapericardial extension of lung cancer.