A collagen network formation effector from leaves of Premna subscandens

As a part of the search for biologically active plant products, M cells, which form a collagen fiber network in vitro after a prolonged culture period, were used. The n-BuOH-soluble fraction of a methanol extract of leaves of Premna subscandens exhibited promotion of collagen network formation by M cells. Extensive isolation work guided by a bioassay afforded a phenylethanoid, acteoside, as an active compound.

Mitochondrial electron transport complex I is a potential source of oxygen free radicals in the failing myocardium

Oxidative stress in the myocardium may play an important role in the pathogenesis of congestive heart failure (HF). However, the cellular sources and mechanisms for the enhanced generation of reactive oxygen species (ROS) in the failing myocardium remain unknown. The amount of thiobarbituric acid reactive substances increased in the canine HF hearts subjected to rapid ventricular pacing for 4 weeks, and immunohistochemical staining of 4-hydroxy-2-nonenal ROS-induced lipid peroxides was detected in cardiac myocytes but not in interstitial cells of HF animals. The generation of superoxide anion was directly assessed in the submitochondrial fractions by use of electron spin resonance spectroscopy with spin trapping agent, 5, 5'-dimethyl-1-pyrroline-N-oxide, in the presence of NADH and succinate as a substrate for NADH-ubiquinone oxidoreductase (complex I) and succinate-ubiquinone oxidoreductase (complex II), respectively. Superoxide production was increased 2.8-fold (P<0.01) in HF, which was due to the functional block of electron transport at complex I. The enzymatic activity of complex I decreased in HF (274+/-13 versus 136+/-9 nmol. min(-1). mg(-1) protein, P<0.01), which may thus have caused the functional uncoupling of the respiratory chain and the deleterious ROS production in HF mitochondria. The present study provided direct evidence for the involvement of ROS in the mitochondrial origin of HF myocytes, which might be responsible for both contractile dysfunction and structural damage to the myocardium.

Amiodarone protects cardiac myocytes against oxidative injury by its free radical scavenging action

BACKGROUND

Oxidative stress plays an important role in the pathophysiology of ischemic heart disease and heart failure, and antioxidants might be beneficial in the treatment of these patients. This study was performed to determine the scavenging effects of amiodarone on oxygen free radicals and its protective effects against oxygen radical-mediated injury in cardiac myocytes.

METHODS AND RESULTS

The formation of the radical spin adduct with hydroxy radical (.OH) in the presence of H(2)O(2) (10 mmol/L) and Fe(3+)-nitrilotriacetate (20 micromol/L) was monitored by electron paramagnetic resonance spectroscopy combined with a spin trapping agent, 5,5-dimethyl pyrroline-N-oxide (DMPO). Amiodarone decreased the intensity of the DMPO-OH signals in a dose-dependent manner (0.1 to 100 micromol/L), whereas other antiarrhythmia drugs such as disopyramide and atenolol had no such effects. Furthermore, amiodarone (10 micromol/L) protected intact adult canine cardiac myocytes against.OH-mediated myocyte injury, as assessed by the degree of morphological change from rod shape to the irreversible hypercontracture state during the exposure of cells to H(2)O(2) and Fe(3+) in vitro.

CONCLUSIONS

Amiodarone can protect cardiac myocytes against oxidative stress-mediated injury by directly scavenging oxygen free radicals. Antioxidant action of amiodarone might potentially contribute to the beneficial effects of this drug in the treatment of patients with ischemic heart disease and congestive heart failure.

Preparation of recombinant rat interleukin-5 by baculovirus expression system and analysis of its biological activities

Rat interleukin-5 (IL-5) cDNA was subcloned from peritoneal cells collected 4 h after intraperitoneal injection of Ascaris suum antigen solution into the immunized rats. Cysteine proteinase-deleted (CPd) rat IL-5 recombinant virus was constructed by inserting rat IL-5 cDNA into CPd virus having a deletion in the cysteine proteinase gene of the silkworm Bombyx mori nuclear polyhedrosis virus. On infection with the CPd rat IL-5 recombinant virus, the silkworm B. mori larvae produced rat IL-5 as a dimeric form in hemolymph. Recombinant rat IL-5 was purified more than 95.5% by anion-exchange chromatography and hydrophobic chromatography. The purified recombinant rat IL-5 promoted the proliferation of T88-M cells in a concentration-dependent manner, and its effect was inhibited by an anti-murine IL-5 neutralizing polyclonal antibody. When bone marrow cells from normal rats were incubated with recombinant rat IL-5 in medium containing methylcellulose, the colony formation by eosinophilic cells was induced. Furthermore, when rat peritoneal eosinophils were incubated with recombinant rat IL-5, the spontaneous decrease in the eosinophil viability was inhibited in time- and concentration-dependent manners. In addition, the recombinant rat IL-5-induced eosinophil survival was inhibited by an anti-murine IL-5 neutralizing polyclonal antibody. These findings suggest that rat IL-5 acts as B-cell growth factor II (BCGF-II), eosinophil differentiation factor (EDF), and eosinophil survival-enhancing factor.

Effect of dietary fats differing in degree of unsaturation on gene expression in rat adipose tissue

To test the possibility that the type of dietary fat affects the expression of proteins involved in adipose tissue metabolism, levels of mRNA for lipoprotein lipase, leptin, glucose transporter 4, and uncoupling protein in adipose tissues were compared among rats fed a low-fat diet (2% safflower oil), and high-fat diets containing 20% saturated fat (palm oil) or unsaturated fat rich in linoleic acid (safflower oil) for 3 weeks. High-fat diets decreased the lipoprotein lipase mRNA level in epididymal but not in perirenal white adipose tissue, but increased it in brown adipose tissue. Leptin gene expression in perirenal white adipose tissue was significantly higher in rats fed high-fat diets than in those fed a low-fat diet. High-fat diets failed, however, to alter this parameter in epididymal white adipose tissue and interscapular brown adipose tissue. mRNA levels of glucose transporter 4, both in epididymal and perirenal white adipose tissues, were lower in rats fed high-fat diets than in those fed a low-fat diet. Uncoupling protein gene expression in interscapular brown adipose tissue was 2-3 times higher in rats fed high-fat diets than in those fed a low-fat diet. The abundance of mRNAs for lipoprotein lipase, leptin, glucose transporter 4 and uncoupling protein was, however, comparable between rats fed diets high in safflower and palm oil. We concluded that the high-fat diet influences gene expression of adipose tissue in a site-specific manner. The difference in the degree of unsaturation of dietary fats is rather irrelevant in modifying the level of mRNAs for proteins related to energy metabolism and expenditure in adipose tissue.

Interferon therapy reduces the risk for hepatocellular carcinoma: national surveillance program of cirrhotic and noncirrhotic patients with chronic hepatitis C in Japan. IHIT Study Group. Inhibition of Hepatocarcinogenesis by Interferon Therapy

BACKGROUND

Previous studies on the effect of interferon therapy on the incidence of hepatocellular carcinoma have not sufficiently assessed degree of liver fibrosis, a major risk factor for hepatocellular carcinoma.

OBJECTIVE

To evaluate the effect of interferon therapy on incidence of hepatocellular carcinoma, adjusting for risk factors, including the degree of liver fibrosis.

DESIGN

Retrospective cohort study.

SETTING

Seven university hospitals and one regional core hospital in Japan.

PATIENTS

2890 patients with chronic hepatitis C who had undergone liver biopsy since 1986. Of these patients, 2400 received interferon and 490 were untreated.

MEASUREMENTS

The degree of liver fibrosis was assessed from stage F0 (no fibrosis) to stage F4 (cirrhosis). Response to interferon was determined virologically and biochemically. Screening for development of hepatocellular carcinoma was performed periodically during an average follow-up of 4.3 years. Effect of interferon therapy on the risk for hepatocellular carcinoma was analyzed by using Cox proportional hazards regression.

RESULTS

Hepatocellular carcinoma developed in 89 interferon-treated patients and in 59 untreated patients. Among untreated patients, the annual incidence of hepatocellular carcinoma increased with the degree of liver fibrosis, from 0.5% among patients with stage F0 or F1 fibrosis to 7.9% among patients with stage F4 fibrosis. The cumulative incidence in treated and untreated patients differed significantly for patients with stage F2 fibrosis (P = 0.0128) and for those with stage F3 fibrosis (P = 0.0011). In multivariate analysis, interferon therapy was associated with a reduced risk for hepatocellular carcinoma (adjusted risk ratio, 0.516 [95% CI, 0.358 to 0.742]; P < 0.001), especially among patients with sustained virologic response (risk ratio, 0.197 [CI, 0.099 to 0.392]), among those with persistently normal serum alanine aminotransferase levels (risk ratio, 0.197 [CI, 0.104 to 0.375]), and among those with alanine aminotransferase levels less than two times the upper limit of normal (risk ratio, 0.358 [CI, 0.206 to 0.622]).

CONCLUSIONS

Interferon therapy significantly reducesthe risk for hepatocellular carcinoma, especially among virologic or biochemical responders.

Effect of dietary sesamin on metabolic fate of an exogenous linolelaidic acid in perfused rat liver

To estimate the relative significance of exogenous and endogenous fatty acid substrates in decreasing hepatic triacylglycerol secretion after sesamin feeding, livers from rats fed diets supplemented with and without sesamin (sesamin: episesamin, 1:1, w/w) were perfused in the presence and absence of an exogenous di-trans isomer of linoleic acid (linolelaidic acid, trans,trans-9,12-octadecadienoic acid). Both exogenous trans fatty acid and dietary sesamin, as compared with respective controls, resulted in a marked increase in hepatic ketogenesis; however, the beta-hydroxybutyrate to acetoacetate ratio was elevated by exogenous fatty acid and decreased by dietary sesamin. On the other hand, hepatic secretions of triacylglycerol, phospholipid and cholesterol were markedly lowered in rats fed sesamin, especially when exogenous fatty acid substrate was provided. The relative significance of the exogenous fatty acid was observed in the dietary sesamin-induced decrease in hepatic secretion of triacylglycerol. These results suggest that increased fatty acid oxidation by dietary sesamin, as reflected by enhanced ketone body production, leads to decreased partition of fatty acid substrates to the esterification pathways, and this in turn reduces the synthesis and secretion of triacylglycerol. The altered metabolism of exogenous fatty acids in the liver was therefore a major determinant for the synthesis and secretion of triacylglycerol.

Interferon therapy reduces the risk for hepatocellular carcinoma: national surveillance program of cirrhotic and noncirrhotic patients with chronic hepatitis C in Japan. IHIT Study Group. Inhibition of Hepatocarcinogenesis by Interferon Therapy

Background

No study has compared the long-term prognoses of hepatitis C patients with hepatitis C virus (HCV) antibody-negative individuals and investigated the effects of interferon (IFN) treatment. To clarify the long-term prognosis of HCV-positive residents of an isolated Japanese island and prospectively investigate the effects of IFN treatment in comparison with the HCV-negative general population.

Methods

HCV antibody was positive in 1,343 (7.6%) of the 17,712 individuals screened. 792 HCV RNA-positive, HBsAg-negative subjects were enrolled. 1,584 HCV antibody-negative, HBsAg-negative general residents were sex- and age-matched to the 792 subjects. A total of 154 <70-year-old patients without liver cirrhosis (LC) or hepatocellular carcinoma (HCC) underwent IFN treatment. The survival rate with all-cause death as the endpoint was determined and causes of death were compared.

Results

The 10- and 20-year survival rates of the hepatitis C and general resident groups were 65.4% and 87.8%, and 40.8% and 62.5%, respectively (p < 0.001; hazard risk ratio, 0.444; 95% confidence interval (CI): 0.389–0.507). There were 167 liver disease-related deaths and 223 deaths from other causes in the hepatitis C group, and 7 and 451, respectively, in the general resident group. Liver disease-related death accounted for 43.8% and 1.5% of deaths in the hepatitis C and general resident groups (p < 0.0001). The cumulative survival rate of the hepatitis C patients without IFN (n = 328) was significantly lower than the gender- and age-matched general resident group (n = 656) (p < 0.0001) but there was no significant difference between the IFN-treated (n = 154) and general resident groups (n = 308).

Conclusions

In the hepatitis C group, the proportion of liver disease-related death was markedly higher, and the survival rate lower, than the general resident group. Introduction of IFN treatment in <70-year-old patients with hepatitis C without LC or HCC improved the survival rate to a level comparable to that of the general residents.

Methylprednisolone and vitamin E therapy in perinatal hypoxic-ischemic brain damage in rats

To study the efficacy of methylprednisolone/vitamin E in reducing cerebral edema and improving the ultimate neuropathological outcome in perinatal cerebral hypoxia-ischemia, 40 seven-day postnatal rats were subjected to right common carotid artery ligation followed by exposure to 8% oxygen at 37 degrees C for 3 h. The animals were divided into groups. Twenty rat pups received an intraperitoneal injection of 30 mg/kg body weight methylprednisolone and vitamin E (100 U/kg) immediately following cerebral hypoxia-ischemia. Control animals received either no therapy (n = 10) or an equivalent volume of normal saline (n = 10). After 72 h of recovery from hypoxia-ischemia, the animals were killed and their brains were examined to measure the water contents in the right and left hemispheres (29 rat pups), whereas the others were killed at 21 days for neuropathological examination. Methylprednisolone/vitamin E-treated rats had significantly less water content in the right hemisphere (87.08 +/- 0.28%, mean +/- S.E.M.) than saline-treated animals (89.07 +/- 0.37%, mean +/- S.E.M., P < 0.0001). Methylprednisolone/vitamin E significantly reduced water content in the right hemisphere of the brain. Neuropathological study was performed on nine rat pups. The brains of four methylprednisolone/vitamin E- and five saline-treated pups were examined at the end of the 21-day recovery period. Two groups of the right cerebral cortex included thinning of the cortex. Significantly less damage was seen in the methylprednisolone/vitamin E-treated pups. Our study suggests that trials of methylprednisolone/vitamin E might be effective if they are given to the mother at risk of fetal hypoxia during labor or to the hypoxic infant right after delivery in preventing hypoxic brain damage.

Evidence for direct binding of fatty acids and eicosanoids to human peroxisome proliferators-activated receptor alpha

The alpha isoform of peroxisome proliferators-activated receptor (PPAR) is activated by fatty acids, their metabolites, and the fibrate class of lipid-lowering agents. To test the ability of these activators to directly bind the ligand-binding domain of human PPARalpha, we performed a competitive binding assay using radiolabeled [(3)H]KRP-297, a known ligand for human PPARalpha. Long-chain fatty acids and eicosanoids were even more potent ligands for human PPARalpha than the hitherto most potent PPARalpha ligand WY-14,643. Moreover, these natural ligands avidly activated this receptor in a transient transcriptional assay. This study provides the direct evidence that human PPARalpha is activated through the direct binding of fatty acids and eicosanoids, as well as of a fibrate, to its ligand-binding domain.

Energy conservation by the H2:heterodisulfide oxidoreductase from Methanosarcina mazei Gö1: identification of two proton-translocating segments

The membrane-bound H2:heterodisulfide oxidoreductase system of the methanogenic archaeon Methanosarcina mazei Gö1 catalyzed the H2-dependent reduction of 2-hydroxyphenazine and the dihydro-2-hydroxyphenazine-dependent reduction of the heterodisulfide of HS-CoM and HS-CoB (CoM-S-S-CoB). Washed inverted vesicles of this organism were found to couple both processes with the transfer of protons across the cytoplasmic membrane. The maximal H+/2e- ratio was 0.9 for each reaction. The electrochemical proton gradient (DeltamicroH+) thereby generated was shown to drive ATP synthesis from ADP plus Pi, exhibiting stoichiometries of 0.25 ATP synthesized per two electrons transported for both partial reactions. ATP synthesis and the generation of DeltamicroH+ were abolished by the uncoupler 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile (SF 6847). The ATP synthase inhibitor N,N'-dicyclohexylcarbodiimide did not affect H+ translocation but led to an almost complete inhibition of ATP synthesis and decreased the electron transport rates. The latter effect was relieved by the addition of SF 6847. Thus, the energy-conserving systems showed a stringent coupling which resembles the phenomenon of respiratory control. The results indicate that two different proton-translocating segments are present in the H2:heterodisulfide oxidoreductase system; the first involves the 2-hydroxyphenazine-dependent hydrogenase, and the second involves the heterodisulfide reductase.

Platanionosides A-C, megastigmane diglycosides from the leaves of Alangium platanifolium

From the leaves of Alangium platanifolium var. platanifolium collected in Fukuoka Prefecture, Japan, three megastigmane diglycosides (1-3) were isolated, along with two known compounds, benzyl alcohol 7-O-beta-D-(6'-O-beta-D-xylopyranosyl)glucopyranoside and Z-hex-3-en-1-ol 1-O-beta-D-glucopyranoside. The structures of the new compounds, named platanionosides A (1), B (2), and C (3) were elucidated by spectroscopic evidence to be 3S,5R,6R,9R, 7E-megastigma-3,9-diol 3,9-di-O-beta-D-glucopyranoside, 3R,9R, 7E-megastigma-5,7-diene-3,9-diol 3,9-di-O-beta-D-glucopyranoside, and 5R,6S,7E-megastigma-3-on-7-en-9-ol 9-O-beta-D-(6'-O-beta-D-xylopyranosyl)glucopyranoside, respectively.

Ubiquitin stress response in postischemic hippocampal neurons under nontolerant and tolerant conditions

Ubiquitin, an essential protein in nonlysosomal proteolytic system, is expressed after metabolic stress to the cell. The authors investigated stress response of ubiquitin in the hippocampus of the Mongolian gerbil after forebrain ischemia. The level of hippocampal ubiquitin was compared with that under ischemic tolerance induced by ischemic preconditioning. The authors also studied ubiquitin gene expression using in situ hybridization method. Transient ischemia resulted in consumption of free ubiquitin and an increase of multiubiquitin chains. These changes were transient in the hippocampus outside of the CA1 region where neurons survived, whereas it was persistent in the CA1 region where neurons were destined to die after ischemia. Under tolerant condition, subsequent ischemia provoked rapid recovery and further increase of free ubiquitin. The signal of ubiquitin messenger ribonucleic acid was continuously detected after ischemia, not only under tolerant conditions, but without tolerance induced by preconditioning. Thus, ubiquitin stress response takes place, at least at a transcriptional level, in dying CA1 neurons. Under tolerant conditions, however, subsequent ischemia in the CA1 region induces the stress response of ubiquitin up to the translational level, leading to the rapid restoration of protein synthesis and to eventual neuronal survival.

Positive inotropic effect of insulin-like growth factor-1 on normal and failing cardiac myocytes

OBJECTIVE

The acute administration of growth hormone (GH) or insulin-like growth factor-1 (IGF-1) improves cardiac performance, possibly contributing to the beneficial effects of GH therapy on heart failure (HF). GH can induce the production of IGF-1 and thus the actions of GH may be mediated through its IGF-1 induction. However, these effects have not yet been demonstrated in failing hearts and the cellular basis of GH or IGF-1-induced inotropic effects remains unknown. We examined the direct effects of GH and IGF-1 on the contractile function and intracellular calcium ([Ca2+]i) homeostasis in normal and failing myocytes.

METHODS

To determine whether GH and IGF-1 have a direct effect on myocardial contractility and whether the GH/IGF-1-induced effect was the results of changes in Ca2+ activation, cell shortening and [Ca2+]i transient were simultaneously measured in the left ventricular myocyte preparations, isolated from normal and rapid pacing-induced HF dogs.

RESULTS

Basal shortening of HF myocytes was reduced by 64% (p < 0.01). In normal and HF myocytes, GH (0.4-40 x 10(-3) IU/ml) had no effect on either cell shortening or [Ca2+]i transients. In normal myocytes, IGF-1 exerted a positive inotropic effect in a time- and dose-dependent manner (25-500 ng/ml), associated with a parallel increase of [Ca2+]i transient amplitude. IGF-1 increased the shortening magnitude in normal (121 +/- 5% increase from baseline, p < 0.05) and HF (118 +/- 4% increase from baseline, p < 0.05) myocytes. It also increased [Ca2+]i transient amplitude in normal and HF cells by 124 +/- 4 and 125 +/- 7%, respectively. The percent increase of cell shortening and [Ca2+]i transient amplitude was comparable between normal and HF myocytes. Furthermore, IGF-1 did not shift the trajectory of the relaxation phase in the phase-plane plots of cell length vs. [Ca2+]i, indicating that it did not change myofilament Ca2+ sensitivity.

CONCLUSIONS

In both normal and HF conditions, IGF-1 exerted an acute direct positive inotropic effect in adult cardiac myocytes by increasing the availability of [Ca2+]i to the myofilaments, possibly explaining the beneficial effect of GH on HF.

Mutations in the NS5A gene predict response to interferon therapy in Japanese patients with chronic hepatitis C and cirrhosis

The virus genotype, serum HCV-RNA level and liver histology are reported to be important factors in the response to interferon therapy. Recent studies have revealed that HCV NS5A 2209-2248 amino acid changes affect the response to interferon therapy of genotype 1b chronic hepatitis C. In contrast, some studies done in western countries have reported no such correlation. In the present study, interferon therapy was given to 58 Japanese patients, including 15 liver cirrhosis patients. NS5A 2209-2248 changes, the serum HCV level, ALT level, age and histology were examined in relation to the interferon effect. Twenty-four of the 58 patients (41%) showed a sustained virological response to the therapy. The responses to interferon therapy were significantly correlated with NS5A 2209-2248 changes (p < 0.0001), the HCV-RNA level (p < 0.0001) and histology (p < 0.0060). Among 15 liver cirrhosis patients, 3 of 6 mutant type patients showed a sustained virological response; 5 intermediate and 4 with wild type virus infected patients showed no responses. In conclusion, NS5A 2209-2248 changes may be a useful predictive marker of response to interferon therapy in addition to the serum HCV RNA level even in histologically advanced patients.

Immunohistochemical detection of human telomerase reverse transcriptase in normal mucosa and precancerous lesions of the stomach

Telomerase activity confers cell immortality through stabilization of the chromosome, participating in the development of a majority of human cancers. Human telomerase reverse transcriptase (TERT) has been identified as a catalytic subunit of telomerase, and is overexpressed in most gastric carcinomas. We immunohistochemically examined the expression of TERT in normal gastric mucosa and candidate precancerous lesions such as intestinal metaplasia and adenoma. In non-neoplastic gastric mucosa including intestinal metaplasia and normal fundic mucosa, weak but significant expression of TERT was detected in nuclei of epithelial cells located in the lower two-thirds of the glands (wider than the proliferative zone). The telomerase activity was found in a half of gastric adenomas, whose levels of the activity were about 10% of those in gastric carcinomas. TERT protein was expressed in the nuclei of the adenoma cells at moderate levels, that were not necessarily comparable with the telomerase activities. These findings overall suggest that TERT expression may be one of the prerequisites for telomerase activation in an early stage of stomach carcinogenesis.

IgE reactivity and cross-reactivity of Japanese monkeys (Macaca fuscata) to Japanese cedar (Cryptomeria japonica) and cypress (Chamaecyparis obtusa) pollen allergens

BACKGROUND

The natural occurrence of Japanese cedar (Cryptomeria japonica, CJ) pollinosis has been reported in Japanese monkeys (Macaca fuscata). However, the reactivity to Japanese cypress (Chamaecyparis obtusa, CO) pollen allergens in these monkeys has not yet been reported.

OBJECTIVES

The present study was designed to investigate the reactivity to CO pollen allergens in monkeys sensitized to CJ pollen allergens.

METHODS

Serum samples from 40 monkeys naturally sensitized to CJ pollen allergens were collected from four troops. We measured the specific IgE to CO pollen allergens and examined the reactivity to the allergens by intradermal test. Cross-reactivity between CJ and CO pollen allergens was examined by ELISA inhibition method. Furthermore, we examined the sensitivity to the allergens by histamine release assay from leucocytes.

RESULTS

All 40 monkeys had specific IgE to crude and purified major allergens (Cha o 1) of CO pollen. The monkeys showed a positive reaction to CO pollen allergens in the intradermal test. Allergenic cross-reactivity between Cha o 1 and Cry j 1 (a major allergen in CJ pollen) was also observed. Specific histamine release to both the major allergens was noted in two monkeys with CJ pollinosis.

CONCLUSION

Japanese monkeys sensitized to Japanese cedar pollen allergens also demonstrate reactivity to Japanese cypress pollen allergens.

Dietary phospholipid-dependent reductions in gene expression and activity of liver enzymes in fatty acid synthesis in fasted-refed rats

The effects of dietary soybean phospholipid, its hydrogenation product and safflower phospholipid on gene expression and the activity of hepatic enzymes in fatty acid biosynthesis were examined in fasted-refed rats. Phospholipid composition of soybean phospholipid and its hydrogenation product were the same, but the hydrogenation product contained negligible amounts of unsaturated fatty acids. Among phospholipid classes, lysophosphatidylcholine and phosphatidylinositol proportions were slightly higher in safflower phospholipid than in soybean phospholipid or its hydrogenation product. Rats were fasted for 2 d and refed a fat-free diet or a diet containing 4% fatty acids either as soybean oil or various phospholipid preparations for 3 d. Compared to the fat-free diet, the soybean oil diet only slightly decreased specific, but not total hepatic fatty acid synthetase and malic enzyme activity, and it was totally ineffective in modulating glucose 6-phosphate dehydrogenase and pyruvate kinase activity under our experimental conditions. The diets containing phospholipids, however, markedly decreased the activity of these enzymes. The extent of reduction was somewhat attenuated with hydrogenated soybean phospholipid as compared with soybean and safflower phospholipids. Dot and Northern blot hybridization using specific cDNA probes showed that, compared to a fat-free diet, diets containing phospholipids profoundly decreased the hepatic mRNA levels of enzymes in fatty acid synthesis. Soybean oil, however, only marginally affected these parameters. Hepatic mRNA levels for enzymes correlated well with enzyme activity. Dietary phospholipids therefore appear to have decreased enzyme activity in fatty acid synthesis primarily by suppressing the mRNA levels of these enzymes. Compared to soybean oil, hydrogenated soybean phospholipid is still effective in decreasing the activity and mRNA level of enzymes in fatty acid synthesis. Therefore, it is difficult to ascribe the potent physiological activity of phospholipid in reducing fatty acid synthesis entirely to polyunsaturated fatty acid moiety.

Intraspousal transmission of GB virus C/hepatitis G virus in an hepatitis C virus hyperendemic area in Japan

OBJECTIVE

An immunoassay for antibodies against an hepatitis G virus (HGV) protein (anti-E2) was recently developed that might serve as a useful marker for diagnosing recovery from HGV infection.

METHODS

We investigated the intraspousal transmission of GB virus C/hepatitis G virus (GBV-C/HGV) using both reverse transcription hemipolymerase chain reaction (RT-hemi-PCR for the 5' untranslated region) and a recently developed anti-E2.

RESULTS

Thirty-two GBV-C/HGV-infected index subjects were selected from an hepatitis C virus hyperendemic area in Japan. Of the 32 subjects, seven (6.4%) were GBV-C/HGV RNA-positive, 24 (21.8%) were anti-E2-positive, and one (0.9%) was both GBV-C/HGV RNA- and anti-E2-positive. Among the 32 spouses of these subjects, GBV-C/HGV RNA, anti-E2, and both GBV-C/HGV RNA and anti-E2 positivity were detected in 0, 6, (18.8%), and one (3.1%) spouses, respectively (the total prevalence of GBV-C/HGV was 7 spouses [21.9%]). Thus, the intraspousal transmission of GBV-C/HGV was undeniable in these seven couples. The respective positive rates of 175 sex- and age-matched controls were 7 (4.0%), 26 (14.9%), and 0 (the total prevalence of GBV-C/HGV was 34 [19.4%]). No significant difference in positive rates was observed between the subjects/spouses and the controls. Five spouses among the seven couples who were positive for any of GBV-C/HGV markers had parenteral risk factors such as blood transfusion, acupuncture, and major surgery.

CONCLUSION

Based on these observations, we cannot draw a definitive conclusion that intraspousal transmission of GBV-C/HGV had occurred among these seven couples.

Noninvasive evaluation of in vivo free radical reactions catalyzed by iron using in vivo ESR spectroscopy

The noninvasive, real time technique of in vivo electron spin resonance (ESR) spectroscopy was used to evaluate free radical reactions catalyzed by iron in living mice. The spectra and signal decay of a nitroxyl probe, carbamoyl-PROXYL, were observed in the upper abdomen of mice. The signal decay was significantly enhanced in mice subcutaneously loaded with ferric citrate (0.2 micromol/g body wt) and the enhancement was suppressed by pre-treatment with either desferrioxamine (DF) or the chain breaking antioxidant Trolox, but only slightly suppressed by the hydroxyl radical scavenger DMSO. To determine the catalytic form of iron, DF was administered at different times with respect to iron loading: before, simultaneously, and after 20 and 50 min. The effect of DF on signal decay, liver iron content, iron excretion, and lipid peroxidation (TBARs) depended on the time of the treatment. There was a good correlation between the signal decay, iron content, and lipid peroxidation, indicating that "chelatable iron" contributed to the enhanced signal decay. The nitroxyl probe also exhibited in vivo antioxidant activity, implying that the process responsible for the signal decay of the nitroxyl probe is involved in free radical oxidative stress reactions catalyzed by iron.

Contribution of peripheral chemoreception to the depression of the hypoxic ventilatory response during halothane anesthesia in cats

BACKGROUND

The effects of inhalational anesthetics on the hypoxic ventilatory response are complex. This study was designed to determine the contribution of peripheral chemoreception to the depression of hypoxic ventilatory response seen with halothane anesthesia.

METHODS

Cats were anesthetized with pentobarbital sodium and alpha-chloralose and artificially ventilated. Respiratory output was evaluated by phasic inspiratory activity of the phrenic nerve. In 12 cats, this activity was measured during inhalation of an hypoxic gas mixture with halothane, 0, 0.1, and 0.8%, with intact or denervated carotid bodies. In 10 cats, a carotid body was isolated from the systemic circulation and perfused with hypoxic Krebs-Ringer solution equilibrated with halothane, 0, 0.1, and 0.8%.

RESULTS

The hypoxic ventilatory response was depressed in a dose-dependent manner during halothane anesthesia. In carotid body perfusion studies, the response was significantly depressed only with halothane, 0.80%.

CONCLUSION

The hypoxic ventilatory response is depressed by a high dose of halothane through a peripheral effect at the carotid body.

Immuno-histochemical detection of human telomerase catalytic component, hTERT, in human colorectal tumor and non-tumor tissue sections

Human telomerase is expressed in germ tissues and in the majority of primary tumors. Cell renewal tissues and some pre-cancerous tissues also have weak telomerase activity. Yet, neither the exact location and frequency of telomerase-positive cells nor the changes in telomerase expression during differentiation or carcinogenesis of individual cells are known. This paper reports on the expression of hTERT (telomerase reverse transcriptase) protein in tumor and non-tumor colorectal tissues by Western blotting and tissue sections by immunohistochemistry using antibodies raised against partial peptides of hTERT. Though telomerase activity and hTERT expression at both mRNA and protein levels were generally higher in tumor part than in non-tumor part, these two were not always correlated: expression of hTERT did not always give rise to high telomerase activity. Colonic carcinoma cell nuclei were stained with anti-hTERT antibodies but not with antigen-preabsorbed antibodies. In normal mucosa, hTERT protein was expressed, though weaker than in carcinoma, in all colonic crypt epithelial cells except those at the tip; the expressing-cell distribution was much wider than that of Ki-67 positive cells which were located at the bottom of the crypt. Isolated crypt contained a significant level of hTERT protein revealed by Western blotting, while having very weak telomerase activity. Telomerase activity was detected in epithelial cells only at the bottom half of the crypt. Specific hTERT-staining was positive in tissue lymphocytes but negative in almost all other stromal cells. It is of interest to see whether a significant level of hTERT expression with low telomerase activity is characteristic of physiologically regenerating tissues containing stem cells. In situ detection of the hTERT protein will permit further analysis of cancer diagnosis and stem cell differentiation.

Reconsideration of senescence, immortalization and telomere maintenance of Epstein-Barr virus-transformed human B-lymphoblastoid cell lines

We review recent data on senescence and immortalization of human B-lymphoblastoid cell lines (LCLs) transformed by the Epstein-Barr virus (EBV). Although EBV-transformed LCLs are generally believed to be immortalized, a series of recent studies, including ours, provided strong evidence that they are mostly mortal and have non-malignant properties, except for a small proportion of LCLs that are immortalized by developing a strong telomerase activity. A large proportion of mortal LCLs have exceptionally long lifespans. Some of them have a lifespan over 150 population-doubling levels, keeping a relatively constant telomere length in spite of the absence of a detectable telomerase activity, suggesting that they maintain telomeres by a pathway other than that using telomerase. Here we propose a model of an alternative pathway to maintain telomeres of such long-lived mortal LCLs by exploiting extra-chromosomal telomere repeat DNA, which was recently found by us.