Biliary atresia in neonates and infants: triangular area of high signal intensity in the porta hepatis at T2-weighted MR cholangiography with US and histopathologic correlation

PURPOSE

To correlate a triangular area of high signal intensity in the porta hepatis on T2-weighted magnetic resonance (MR) cholangiograms of biliary atresia with ultrasonographic (US) and histopathologic findings in a portal mass observed during a Kasai procedure.

MATERIALS AND METHODS

Twenty-one consecutive neonates and infants (age range, 13-88 days; mean age, 59 days) with cholestasis underwent US and single-shot MR cholangiography. In 12 patients with biliary atresia diagnosed at histopathologic examination, MR cholangiographic findings in the porta hepatis were correlated with US and histopathologic findings in the portal mass.

RESULTS

At US, eight of the 12 patients had round, linear, or tubular hypoechoic portions within a triangular cord; MR cholangiography revealed a triangular area of high signal intensity confined to the porta hepatis. Histopathologic examination of the portal mass revealed a cystic or cleftlike lesion surrounded by loose myxoid mesenchyme and platelike fetal bile ducts. Neither the large cystic lesion without ductal epithelium nor the small cleftlike lesion with scanty epithelium demonstrated bile staining. Similar areas of high signal intensity were not seen on T2-weighted images in the remaining patients (four with biliary atresia and nine with neonatal hepatitis).

CONCLUSION

In biliary atresia, T2-weighted single-shot MR cholangiography can show a triangular area of high signal intensity in the porta hepatis that may represent cystic dilatation of the fetal bile duct.

Differentiation of Salmonella enterica serotype gallinarum biotype pullorum from biotype gallinarum by analysis of phase 1 flagellin C gene (fliC)

Salmonella enterica serotype gallinarum biotype gallinarum and biotype pullorum are non-motile and pathogenic avian strains. Biotype gallinarum causes fowl typhoid and biotype pullorum is the cause of pullorum disease in chickens. The two biotypes could be differentiated based on biochemical characteristics. However, conventional culture and biochemical assays are time-consuming, laborious and need sterile laboratory practices. Although the two biotypes, gallinarum and pullorum are non-motile, they possess the phase 1 flagellin C gene. The variable regions of the flagellin C gene from 41 biotype pullorum and 52 biotype gallinarum were amplified by colony-PCR and analyzed by single strand conformational polymorphism (SSCP) method. Differences in SSCP electrophoretic patterns were confirmed by nucleotide sequencing. In addition, PCR-RFLP with Hinp1I was also successfully applied to differentiate the two biotypes. These results suggested that the variable regions of fliC could be used as a genetic marker to differentiate biotype gallinarum from biotype pullorum.

Studies on the antithrombotic and antiplatelet activities of NQ304, a newly synthesized naphthoquinone derivative

The effect of p6304 (2-chloro-3-(4-hexylphenyl)-amino-1,4-naphthoquinone) as a novel antithrombotic agent was investigated. NQ304 was found to inhibit platelet aggregation in human platelets in vitro and in rat ex vivo, and murine pulmonary thrombosis in vivo. NQ304 potently inhibited adenosine diphosphate (ADP), collagen, epinephrine and calcium ionophore-induced human platelet aggregation in vitro dose-dependently. In the ex vivo study, oral administration of NQ304 significantly inhibited platelet aggregation in rats. However, NQ304 was found not to affect the coagulation system, since it did not change the prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT). The agent prevented death due to pulmonary thrombosis by the platelet aggregates in mice in vivo. In the mouse tail bleeding time test, NQ304 showed a significant prolongation of the tail bleeding time in conscious mice. These results suggest that a principal antithrombotic effect of NQ304 may be due to the antiplatelet aggregation activity but not to anticoagulation activity.

Radiologic findings of Mirizzi syndrome with emphasis on MRI

We have reported a case of Mirizzi syndrome preoperatively diagnosed using MR cholangiopancreatography. MRCP and T2-weighted image using a single-shot fast spin-echo sequence accurately depicted all components of Mirizzi syndrome, including impacted stone in the neck of the gallbladder compressing the common hepatic duct and wall-thickening of the gallbladder without any evidence of malignancy. The combination of MRCP and T2-weighted image can be counted on to replace conventional modalities of diagnosing Mirizzi syndrome without any loss of diagnostic accuracy.

Antiplatelet and antithrombotic activities of NQ301, 2-chloro-3-(4-acetophenyl)-amino-1,4-naphthoquinone

The antiplatelet and antithrombotic activities of a newly synthesized NQ301, 2-chloro-3-(4-acetophenyl)-amino-1,4-naphthoquinone, were investigated on human platelet aggregation in vitro and rats ex vivo, and murine pulmonary thrombosis in vivo. NQ301 potently inhibited ADP-, collagen-, epinephrine- and calcium ionophore A23187-induced human platelet aggregation in a concentration-dependent manner in vitro. NQ301 significantly inhibited platelet aggregation in orally administered rats ex vivo. NQ301 prevented death due to pulmonary thrombosis in mice dose-dependently in vivo. NQ301 also showed significant prolongation of tail bleeding time in conscious mice. However, NQ301 did not alter such coagulation parameters as activated partial thromboplastin time, prothrombin time, and thrombin time in human plasma. These results suggest that NQ301 may be a promising antithrombotic agent, and the antithrombotic activity of NQ301 may be due to antiplatelet aggregation activity but not to in vitro anticoagulation.

Antithrombotic activities of green tea catechins and (-)-epigallocatechin gallate

The antithrombotic activities and mode of action of green tea catechins (GTC) and (-)-epigallocatechin gallate (EGCG), a major compound of GTC, were investigated. Effects of GTC and EGCG on the murine pulmonary thrombosis in vivo, human platelet aggregation in vitro, and ex vivo, and coagulation parameters were examined. GTC and EGCG prevented death caused by pulmonary thrombosis in mice in vivo in a dose-dependent manner. They significantly prolonged the mouse tail bleeding time of conscious mice. They inhibited adenosine diphosphate- and collagen-induced rat platelet aggregation ex vivo in a dose-dependent manner. GTC and EGCG inhibited ADP-, collagen-, epinephrine-, and calcium ionophore A23187-induced human platelet aggregation in vitro dose dependently. However, they did not change the coagulation parameters such as activated partial thromboplastin time, prothrombin time, and thrombin time using human citrated plasma. These results suggest that GTC and EGCG have the antithrombotic activities and the modes of antithrombotic action may be due to the antiplatelet activities, but not to anticoagulation activities.

p53 negatively regulates cdc2 transcription via the CCAAT-binding NF-Y transcription factor

The p53 tumor suppressor protein regulates the transcription of regulatory genes involved in cell cycle arrest and apoptosis. We have reported previously that inducible expression of the p53 gene leads to the cell cycle arrest both at G(1) and G(2)/M in association with induction of p21 and reduction of mitotic cyclins (cyclin A and B) and cdc2 mRNA. In this study, we investigated the mechanism by which p53 regulates transcription of the cdc2 gene. Transient transfection analysis showed that wild type p53 represses whereas various dominant negative mutants of p53 increase cdc2 transcription. The cdc2 promoter activity is not repressed in cells transfected with a transactivation mutant, p53(22/23). An adenovirus oncoprotein, E1B-55K inhibits the p53-mediated repression of the cdc2 promoter, while E1B-19K does not. Since the cdc2 promoter does not contain a TATA sequence, we performed deletion and point mutation analyses and identified the inverted CCAAT sequence located at -76 as a cis-acting element for the p53-mediated regulation. We found that a specific DNA-protein complex is formed at the CCAAT sequence and that this complex contains the NF-Y transcription factor. Consistently, a dominant negative mutant of the NF-YA subunit, NF-YAm29, decreases the cdc2 promoter, and p53 does not further decrease the promoter activity in the presence of NF-YAm29. These results suggest that p53 negatively regulates cdc2 transcription and that the NF-Y transcription factor is required for the p53-mediated regulation.

Immunogenicity of alpha-toxin, capsular polysaccharide (CPS) and recombinant fibronectin-binding protein (r-FnBP) of Staphylococcus aureus in rabbit

This study was conducted to evaluate the antibody levels of alpha-toxin, capsular polysaccharides (CPS) and fibronectin-binding protein (FnBP) in rabbits immunized with an experimental vaccine against Staphylococcus aureus and to develop the bovine mastitis subunit vaccine in the future. Enzyme immunoassay was used for detection of IgG antibodies against staphylococcal CPS, alpha-toxin and FnBP. The levels of specific antibodies against CPS, alpha-toxin and FnBP in immunized rabbits were significantly increased after first immunization compared with control animals (p<0.05). Of three antigen used in vaccine, immunogenicity of CPS was relatively lower, compared with those of alpha toxin and fibronectin binding protein. Numbers of S. aureus in blood of immunized groups were lower than those of control group after bacterial challenge. But the bacterial numbers among immunized groups were not significantly different. S. aureus counts in excised organs were significantly lower in all immunized rabbits than in PBS-control group (p<0.05). The present study showed that alpha-toxin, capsular polysaccharide and fibronectin binding protein included in a subunit vaccine were protective.

Contrast enhancement of small hepatocellular carcinoma: usefulness of three successive early image acquisitions during multiphase dynamic MR imaging

OBJECTIVE

The purpose of this study was to document the usefulness of early triphasic image acquisition during gadolinium-enhanced multiphase dynamic MR imaging for the detection of contrast enhancement in small hepatocellular carcinoma.

SUBJECTS AND METHODS

Dynamic MR imaging was performed in 332 patients at 1.5 T using a T1-weighted fast low-angle shot sequence (TR range/TE, 113-130/4.1; flip angle, 80 degrees). With the start of bolus injection of gadolinium dimeglumine (0.1 mmol/kg) into the antecubital vein, three sets of contrast-enhanced images of the entire liver were obtained serially at 10, 35, and 60 sec. Contrast enhancement of the tumor detected on each phase was evaluated in conjunction with the unenhanced T1-weighted images for 52 patients with small hepatocellular carcinomas up to 2 cm in diameter (n = 79).

RESULTS

The first phase images depicted a larger number (n = 57) of contrast enhancement of small hepatocellular carcinoma tumors than the second (n = 44) or third phase images (n = 14). Twenty-six lesions were enhanced only during the first phase, and nine, during the second phase. The detection rate of contrast enhancement in the combination of first and second phases was the same as the overall detection rate for all three phases (70/79, 89%) and significantly higher than those of each phase.

CONCLUSION

Early multiple image acquisition is helpful for the assessment of small hepatocellular carcinoma and is enabled by the high detection rate of contrast enhancement regardless of individual variations in the timing of enhancement.

Use of TUNEL staining to detect apoptotic cells in the lungs of cattle experimentally infected with Pasteurella haemolytica

Lung sections taken from calves with experimental Pasteurella haemolytica respiratory infection exhibited increased numbers of TUNEL positive cells with time after challenge. This finding suggests that P. haemolytica, or toxins and other components released by the organism, induces apoptosis in bovine leukocytes in vivo. By so doing this might impair host defense and contribute in part to the severe pneumonia that characterizes bovine pasteurellosis.

DNA-induced conformational change of Gaf1, a novel GATA factor in Schizosaccharomyces pombe

A novel GATA factor in Schizosaccharomyces pombe, Gaf1, containing one zinc-finger motif was studied for conformational change that was induced by DNA-binding. Gaf1 was shown to bind to the upstream activation sequence of a gene in Saccharomyces cerevisiae containing GATA element by gel mobility shift assay. Circular dichroism spectra of Gaf1 indicated an increase of alpha-helix content of Gaf1 occurred upon binding to the upstream activation sequence. These results suggest that the binding of Gaf1 to the GATA element is required for the conformational change that may precede transactivation of the target gene(s).

Biodegradable nanoparticles containing doxorubicin-PLGA conjugate for sustained release

PURPOSE

Doxorubicin was chemically conjugated to a terminal end group of poly(D,L-lactic-co-glycolic acid) [PLGA] and the doxorubicin-PLGA conjugate was formulated into nanoparticles to sustain the release of doxorubicin.

METHODS

A hydroxyl terminal group of PLGA was activated by p-nitrophenyl chloroformate and reacted with a primary amine group of doxorubicin for conjugation. The conjugates were fabricated into ca. 300 nm size nanoparticles by a spontaneous emulsion-solvent diffusion method. The amount of released doxorubicin and its PLGA oligomer conjugates was quantitated as a function of time. The cytotoxicity of the released species was determined using a HepG2 cell line.

RESULTS

Loading efficiency and loading percentage of doxorubicin-PLGA conjugate within the nanoparticles were 96.6% and 3.45 (w/w) %, respectively while those for unconjugated doxorubicin were 6.7% and 0.26 (w/w) %, respectively. Both formulation parameters increased dramatically due to the hydrophobically modified doxorubicin by the conjugation of PLGA. The nanoparticles consisting of the conjugate exhibited sustained release over 25 days, whereas those containing unconjugated free doxorubicin showed rapid doxorubicin release in 5 days. A mixture of doxorubicin and its PLGA oligomer conjugates released from the nanoparticles had comparable IC50 value in a HepG2 cell line compared to that of free doxorubicin. Sustained drug release was attributed to the chemical degradation of conjugated PLGA backbone, which permitted water solubilization and subsequent release of doxorubicin conjugated PLGA oligomers into the medium.

CONCLUSIONS

The conjugation approach of doxorubicin to PLGA was potentially useful for nanoparticle formulations that require high drug loading and sustained release. The doxorubicin-PLGA oligomer conjugate released in the medium demonstrated a slightly lower cytotoxic activity than free doxorubicin in a HepG2 cell line.

Focal eosinophilic infiltration of the liver: a mimick of hepatic metastasis

We present three cases of focal eosinophilic infiltration in the liver that mimicked hepatic malignancy on computed tomography during hepatic arteriography (CTHA) and computed tomography during arterial portography (CTAP). In all patients, focal eosinophilic liver infiltration appeared as a solitary nodule or as two nodules without hepatosplenomegaly and showed homogeneous hyperattenuation on CTHA and hypoattenuation on CTAP.

Improved fluorescent determination method of cellular sphingoid bases in high-performance liquid chromatography

Precolumn orthophthaldehyde (OPA) labeling method of sphingoid bases, sphingosine and sphinganine, was investigated to obtain high fluorescent detectability. In order to improve the fluorescent yield, we investigated the optimal solubility of sphingoid bases for five pre-incubation solvents by incorporating the heating procedure before OPA derivatization. The pre-incubation in ethanol prominently increased the fluorescent peak height of OPA derivative for each sphingoid bases in high performance liquid chromatography. About ten-fold increase of detectability was archived by pre-incubating lipid extracts pellets in ethanol at 60 degrees C for 30 min. Optimal derivatization was performed in 30 min at ambient temperature and the fluorescent intensity of OPA derivative was stable for two weeks at 4 degrees C. The detection limit of sphingosine was 0.1 pmol as injected amount. This method was applied to the determination of cellular sphingosine and sphinganine in various human lung cancer cells. This OPA procedure was prospective to be useful for quantitating the amount of sphingoid bases in other cancer cells.

T2-weighted fast spin-echo MR findings of adenocarcinoma of the uterine cervix: comparison with squamous cell carcinoma

The purpose of this study was to investigate the differences in MR findings of adenocarcinoma (AC) and squamous cell carcinoma (SCC) of the uterine cervix and to compare MR findings with pathologic findings. MR images of 17 patients with pathologically proven AC, using a fast spin-echo (FSE) T2-weighted image (T2WI) with pelvic phased-array coil on a 1.5-T unit, were retrospectively evaluated. After measurement of the signal intensity (SI) ratios of the region of interest between tumors and gluteus maximus muscle, we compared the ratios of AC with those of 16 patients with SCC. AC showed relatively high SI on FSE T2WI with multiseptated lesions in four cases and hydrometrocolpos in three cases. The mean SI ratio was 3.82 +/- 1.68 in AC and 2.35 +/- 0.42 in SCC (p < 0.0001, t-test). Multiple tumorous glands with cytoplasmic and intraglandular mucin or serous fluid were pathologically found in AC, but SCC revealed the compact cellularity of stratified squamous tumor cells. The cervical AC showed higher SI than SCC on FSE T2WI with occasional multiseptated lesions and hydrometrocolpos. If the SI ratio of the tumor was more than 3.0, AC could be diagnosed with a sensitivity of 68.8% and a specificity of 100%.

Structural elements of ADP-ribosylation factor 1 required for functional interaction with cytohesin-1

ADP-ribosylation factor 1 (ARF1) is a 20-kDa guanine nucleotide-binding protein involved in vesicular trafficking. Conversion of inactive ARF-GDP to active ARF-GTP is catalyzed by guanine nucleotide exchange proteins such as cytohesin-1. Cytohesin-1 and its Sec7 domain (C-1Sec7) exhibit guanine nucleotide exchange protein activity with ARF1 but not ARF-like protein 1 (ARL1), which is 57% identical in amino acid sequence. With chimeric proteins composed of ARF1 (F) and ARL1 (L) sequences we identified three structural elements responsible for this specificity. Cytohesin-1 increased [35S]guanosine 5'-(gamma-thio)triphosphate binding to L28/F (first 28 residues of L, remainder F) and to a much lesser extent F139/L, and mut13F139/L (F139/L with random sequence in the first 13 positions) but not Delta13ARF1 that lacks the first 13 amino acids; therefore, a nonspecific ARF N terminus was required for cytohesin-1 action. The N terminus was not, however, required for that of C-1Sec7. Both C-1Sec7 and cytohesin-1 effectively released guanosine 5'-(gamma-thio)triphosphate from ARF1, but only C-1Sec7 displaced the nonhydrolyzable GTP analog bound to mut13F139/L, again indicating that structure in addition to the Sec7 domain is involved in cytohesin-1 interaction. Some element(s) of the C-terminal region is also involved, because replacement of the last 42 amino acids with ARL sequence in F139L decreased markedly the interaction with cytohesin-1. Participation of both termini is consistent with the crystallographic structure of ARF in which the two terminal alpha-helices are in close proximity. ARF1 residues 28-50 are also important in the interaction with cytohesin-1; replacement of Lys-38 with Gln, the corresponding residue in ARL1, abolished the ability to serve as substrate for cytohesin-1 or C-1Sec7. These studies have defined multiple structural elements in ARF1, including switch 1 and the N and C termini, that participate in functional interactions with cytohesin-1 (or its catalytic domain C-1Sec7), which were not apparent from crystallographic analysis.

Molecular cloning and functional expression of a phospholipase D from cabbage (Brassica oleracea var. capitata)

We cloned and expressed a full-length cDNA encoding a phospholipase D of type alpha (PLDalpha) from cabbage. Analysis of the cDNA predicted an 812-amino-acid protein of 92.0 kDa. The deduced amino acid sequence of cabbage PLD has 83% and 80% identity with Arabidopsis PLDalpha and castor bean PLD, respectively. Expression of this cDNA clone in E. coli shows a functional PLD activity similar to that of the natural PLD.

Colorectal mucinous carcinoma: findings on MRI

PURPOSE

The purpose of this work was to define the characteristic MR features of colorectal mucinous carcinomas and to correlate the mucin pool with the signal intensity of this tumor.

METHOD

MRI of 12 cases of pathologically proven colorectal carcinoma containing mucin was evaluated. We analyzed the signal intensity of tumor on T1- and T2-weighted MR images and correlated the area of intratumoral high signal intensity on T2-weighted images with the mucinous pool on the pathologic specimens. Two radiologists independently estimated the area of high signal intensity in the tumor on T2-weighted images and one pathologist estimated the amount of mucinous pool in the pathologic specimen.

RESULTS

In 9 (75%) of 12 cases, focal or diffuse high signal intensity areas were detected on T2-weighted fast spin echo images. In seven cases in which mucin pools were seen macroscopically, partial (n = 3) or diffuse high signal intensity areas were noted on the T2-weighted images. Among the five cases in which microscopic mucinous pools were detected on the pathologic slides, three cases showed no high signal foci on MR images, and in the remaining two cases, high signal intensity areas were noted as small foci.

CONCLUSION

Intratumoral high signal intensity on T2-weighted fast spin echo MR images occurs in mucinous carcinomas and correlates with the mucin pools on pathologic specimens.

Hepatic cavernous hemangioma: sonographic patterns and speed of contrast enhancement on multiphase dynamic MR imaging

OBJECTIVE

Our purpose was to investigate a correlation between the speed of contrast enhancement in patients with hepatic cavernous hemangioma revealed by dynamic MR imaging and the internal echo pattern revealed by sonography.

MATERIALS AND METHODS

Forty-five patients underwent multiphase IV contrast-enhanced dynamic MR imaging that revealed 71 hepatic cavernous hemangiomas less than 4 cm in diameter; the MR findings were compared with the sonographic findings in these patients. On MR imaging, the hemangiomas were classified as rapid-, intermediate-, and slow-enhancing. We classified sonographic features as hypoechoic, iso- or mixed-echoic, and hyperechoic according to the relative echogenicity seen between lesions and the surrounding hepatic parenchyma. Sonographic patterns and MR imaging findings of individual lesions were then compared.

RESULTS

Rapid-enhancing hemangiomas revealed on dynamic MR imaging tended to be hypoechoic on sonography (18/24, 75%; p = .0143), and lesions that were slow-enhancing on MR imaging tended to be hyperechoic (26/29, 90%; p < .0001). Hypoechoic lesions on sonography tended to be rapid-enhancing on dynamic MR imaging (18/18, 100%). Likewise, hyperechoic lesions on sonography tended to be slow-enhancing on MR imaging (26/33, 79%; p = .0009).

CONCLUSION

In most patients with hepatic cavernous hemangiomas, we found that the speed of contrast enhancement on multiphase dynamic MR imaging enabled us to predict the echo pattern in sonography and vice versa.

Molecular cloning of gaf1, a Schizosaccharomyces pombe GATA factor, which can function as a transcriptional activator

As a first step to elucidate the functions of Schizosaccharomyces pombe (S. pombe) GATA factors, we have isolated the gaf1+ gene (GATA-factor like gene) in S. pombe. The predicted amino acid (aa) sequence of Gaf1 reveals a single zinc finger domain typical of fungal GATA factors, and the zinc finger exhibits 60% aa identity to that of human GATA-1. The open reading frame of Gaf1 predicts a protein of Mr 32 kDa consisting of 290 intronless amino acids. Disruption of this gene has no effect on cell viability and growth rate. The GST-Gaf1 fusion protein binds specifically to GATA motifs of its own promoter as well as DAL7 UAS, a canonical GATA motif of Saccharomyces cerevisiae (S. cerevisiae) The specific DNA-binding activity resides within the N-terminal half of Gaf1 (Gaf1N; aa 1-120) containing the zinc finger, whereas the C-terminal half (Gaf1C; aa 121-290) contains transactivation sequences that induce the expression of the lacZ reporter when fused to the GAL4 DNA binding domain. These results demonstrate that Gaf1 may function as a transcriptional activator consisting of DNA-binding and transactivation domains.

MR imaging during arterial portography for assessment of hepatocellular carcinoma: comparison with CT during arterial portography

OBJECTIVE

The purpose of this study was to document the usefulness of MR imaging during arterial portography (MRAP) versus CT during arterial portography (CTAP) in the diagnosis and assessment of hepatocellular carcinoma.

SUBJECTS AND METHODS

In addition to static T1- and T2-weighted MR imaging, MRAP was performed immediately after hepatic angiography through contrast material injection into intraarterially placed catheters (superior mesenteric or splenic artery) in 21 patients with nodular hepatocellular carcinoma. CTAP was performed afterward for each patient. The sensitivity and specificity of MRAP for lesion detection and the differential diagnosis of hepatocellular carcinoma were compared with the sensitivity and specificity of CTAP.

RESULTS

MRAP revealed more perfusion defects (n = 56) than did CTAP (n = 46). The sensitivity for detection of hepatocellular carcinoma was higher for MRAP (94%) than for CTAP (83%); however, the difference was not statistically significant (p > .05). More hepatocellular nodules with unknown malignant potential were revealed on MRAP (n = 7) than on CTAP (n = 2). For the differential diagnosis of perfusion defects commonly revealed by both techniques, more benign lesions and pseudolesions (n = 14) were shown on MRAP through the combined interpretation with static images than on unenhanced and contrast-enhanced CTAP (n = 11).

CONCLUSION

Because of its high sensitivity and its ability to enable radiologists to differentiate benign from malignant conditions, MRAP may have merit compared with CTAP in the assessment of hepatocellular carcinoma.

Formation of 8-oxodeoxyguanosine in liver DNA and hepatic injury by peroxisome proliferator clofibrate and perfluorodecanoic acid in rats

In this study, we examined whether the production of hydrogen peroxide by peroxisome proliferators causes oxidative DNA damage in the form of 8-oxodeoxyguanosine (8-oxodG) and hepatic injury, and whether it is related to their tumor-promoting or carcinogenic activities in female rats treated with the peroxisome proliferators clofibrate and perfluorodecanoic acid (PFDA). Clofibrate has tumor-promoting and carcinogenic activities, whereas PFDA does not. We also tested whether peroxisome proliferators directly induce mutagenic events in Salmonella typhimurium strains TA 98 and TA 1537. Rats were treated either by 5% clofibrate in diet or by an i.p. injection of corn oil containing 10 mg/kg body weight of PFDA every week for 2 or 8 weeks. 8-OxodG in liver DNA was analyzed by HPLC coupled with an electrochemical detector. Hepatic injury was evidenced by liver enlargement and by levels of serum enzymes, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and hepatic gamma-glutamylpeptidase (gamma-GT) activity. Clofibrate and PFDA increased the activity of catalase about or less than 2-fold, whereas FAO activity was increased about 6 to 7-fold by clofibrate and about 3 to 4-fold by PFDA. Neither clofibrate nor PFDA induced mutation at any dose tested. Clofibrate significantly increased the formation of 8-oxodG, but PFDA only slightly increased. Serum AST and ALT levels, and hepatic gamma-GT activity were not significantly changed at both time points, whereas the ratio of liver/body weight was significantly increased by clofibrate and PFDA at 8 weeks. These data imply that the magnitude of the production of hydrogen peroxide-generated FAO is related to the induction of oxidative DNA damage by peroxisome proliferators, and their tumor-promoting or carcinogenic activities. However, the effect of hydrogen peroxide in hepatic injury is not clear.

Isolation of a novel heat shock protein 70-like gene, pss1+ of Schizosaccharomyces pombe homologous to hsp110/SSE subfamily

A novel heat shock protein 70 (HSP70) gene, pss1+, of fission yeast, Schizosaccharomyces pombe (S. pombe), has been isolated as a multicopy suppressor of a synthetic lethal mutant of ras1+, which shows severe retardation of growth and aggregation phenotype when the ras1 gene function is absent. The pss1+ gene functionally complements the growth defect of the mutant. Sequence analysis revealed that pss1+ encodes an open reading frame (ORF) of 730amino acids that is homologous to the HSP70 family proteins. The Pss1 has high homology to the Saccharomyces cerevisiae (S. cerevisiae) heat shock protein Sse1p/Msi3p (43% identity) that belongs to the HSP110/SSE subfamily of HSP70. The consensus nucleotide sequence of the heat shock element (HSE) was found in the upstream region of pss1+ gene. The transcript level of pss1+ was moderately abundant during steady-state growth at 25 degrees C and increased a few-fold upon shifting to 42 degrees C. Furthermore, transcription of pss1+ increased in nitrogen-starved conditions. Disruption of the pss1+ gene confers a temperature-sensitive growth phenotype and unexpectedly causes the increase in thermotolerance in S. pombe.

Isolation of a new member of DnaJ-like heat shock protein 40 (Hsp40) from human liver

A new member of Hsp40, HLJ1, consisting of 337 amino acids, was cloned from a human liver cDNA library. The deduced amino acid sequence of HLJ1 has an 84% homology (69% identity) with that of HDJ-1 isolated from human placenta. Northern analysis showed that expression of the HLJ1 gene is heat-inducible and its transcription shows some degree of preference in heart, skeletal muscle, and pancreas.

Activity wheel running blunts increased plasma adrenocorticotrophin (ACTH) after footshock and cage-switch stress

We examined whether chronic circadian physical activity attenuates hypothalamic-pituitary-adrenal hormone responses after footshock with or without cage-switch stress. Young (45 g) male Fischer 344 rats were randomly assigned to individual suspended home cages (HC) or cages with activity wheels (AW) (12 h:12 h light-dark photoperiod). After 6 weeks, each animal from a pair matched on mass (HC and AW) and average weekly running distance (AW) was randomly assigned to controllable or uncontrollable footshock on 2 days separated by 24 h. Half the animals were returned to the HC after the first day of shock, and half were switched to a new shoebox cage. One animal of each pair could end the shock for both rats by performing an FR-2 lever press. The yoked animal could not control the shock. After shock on Day 2, trunk blood was collected after decapitation. Plasma adrenocorticotrophin (ACTH), corticosterone, and prolactin were determined by radioimmunoassay. ANOVA for a 2 Group (AW vs. sedentary) x 2 Test (controllable vs. uncontrollable shock) x 2 Condition (HC vs. cage-switch) design indicated a Group x Test x Condition effect [F(1, 48) = 5.07, p = 0.03] and a Test main effect [F(1, 47) = 6.93, p = 0.01] for ACTH. ACTH was higher for sedentary animals after uncontrollable footshock under cage-switch conditions and higher after uncontrollable versus controllable footshock when averaged across groups and cage conditions. No effects were found for corticosterone or prolactin. Our results extend to activity wheel running prior findings of a cross-stressor attenuation in plasma [ACTH] in response to cage-switch after treadmill exercise training, though the cross-stressor effect was additive with footshock. Consistent with our prior reports, the cross-stressor effect of wheel running was not apparent after footshock administered under home-cage conditions.