Cry j 1 isoforms derived from Cryptomeria japonica trees have different binding properties to monoclonal antibodies

BACKGROUND

We identified five Cryptomeria japonica trees producing Cry j 1 isoforms that cannot be detected in a sandwich ELISA using two monoclonal antibodies, J1B01 and J1B07, suggesting that the binding affinity of these isoforms for both monoclonal antibodies is low.

OBJECTIVES

The binding properties of the Cry j 1 isoforms produced by five trees to J1B07 and J1B01 were examined. The complementary DNA (cDNA) sequences of the Cry j 1 isoforms were also determined.

METHODS

To clarify the binding properties of these Cry j 1 isoforms to J1B01 and J1B07, Cry j 1 was quantified in pollen samples collected from each of the five trees, by sandwich ELISAs using polyclonal antibodies and either J1B01 or J1B07. The cDNA sequences of isoforms with different binding properties were determined. To test the assumption that amino acid substitutions affect the binding affinities of Cry j 1 isoforms for monoclonal antibodies, cleaved amplified polymorphic sequences (CAPS) markers representing the putative polymorphisms were used to analyse additional trees.

RESULTS

Four of the five trees produced Cry j 1 isoforms with extremely low binding affinity for J1B07, whereas the other tree produced two different isoforms with low binding affinity for either J1B01 or J1B07. Cry j 1-encoding cDNA sequences for one of the four trees and for the exceptional fifth tree indicate that amino acid substitutions at positions 55 and 352 in mature Cry j 1 affect its binding to J1B01 and J1B07, respectively. This was supported by the results of CAPS analysis.

CONCLUSION

The existence of Cry j 1 isoforms with low binding affinity for either J1B01 or J1B07 was established. Furthermore, a single amino acid substitution is involved in this difference in binding affinity for each monoclonal antibody.

Effects of sodium benzoate on the complications of 1.5% glycine solution using two different intravesical pressures during bladder irrigation

BACKGROUND

In this experimental study we researched the effects of sodium benzoate on the complications of 1.5% glycine solution using with two different intravesical pressures during bladder irrigation.

METHODS

Thirty-six male adult New Zealand rabbits with body weight ranging from 1500 to 2800 g were used in the experiments. The rabbits were randomly allocated to four groups. In groups 1 and 2, 500 ml of 1.5% gylcine was used as irrigating fluid during 30 min, but only group 2 received 500 mg kg(-1) of sodium benzoate treatment by oral route immediately after irrigation. In groups 3 and 4, 500 ml of 1.5% glycine was used as irrigating fluid during 60 min, but only group 4 received the same treatment as group 2. Ammonia, urea, sodium, potassium, hemoglobin, hemotocrit and platelet levels were studied at preirrigation and postirrigation on the 4 h and 24 h. Also electrocardiographic (ECG) changes were monitored at the same time with blood parameters.

RESULTS

At 4 h postirrigation, Na+ levels were decreased significantly in group 1 and non-significantly in group 3 when compared with preirrigation levels. But these levels were not changed in groups 2 and 4. Both at 4 h and 24 h, ammonia and urea levels were significantly increased in groups 1 and 3. Ammonia level was decreased but the urea level was not changed in groups 2 and 4 at the same time points. K+ level was significantly changed only in group 1 at 4 h and 24 h. Hemoglobin and hemotocrit concentrations were decreased both at 4 h and 24 h compared with preirrigation levels in all groups. Also there were ECG changes between the treated and untreated groups.

CONCLUSION

Sodium benzoate was very effective against the complications of 1.5% glycine during bladder irrigation experimentally. But this needs further investigation, especially for the applicability of this new treatment model in human TURP syndrome.

Significantly enhanced stability of glucose dehydrogenase by directed evolution

An NaCl-independent stability-enhanced mutant of glucose dehydrogenase (GlcDH) was obtained by using in vitro directed evolution. The family shuffling method was applied for in vitro directed evolution to construct a mutant library of GlcDH genes. Three GlcDH-coding genes from Bacillus licheniformis IFO 12200, Bacillus megaterium IFO 15308 and Bacillus subtilis IFO 13719 were each cloned by direct PCR amplification into the p Trc99A expression vector and expressed in the host, Escherichia coli. In addition to these three GlcDH genes, a gene encoding a previously obtained GlcDH mutant, F20 (Q252L), derived from B. megaterium IWG3, was also subjected to directed evolution by the family shuffling method. A highly thermostable mutant, GlcDH DN-46, was isolated in the presence or absence of NaCl after the second round of family shuffling and filter-based screening of the mutant libraries. This mutant had only one novel additional amino acid residue exchange (E170K) compared to F20, even though DN-46 was obtained by family shuffling of four different GlcDH genes. The effect of temperature and pH on the stability of the GlcDH mutants F20 and DN46 was investigated with purified enzymes in the presence or absence of NaCl. In the absence of NaCl, F20 showed very poor thermostability (half-life =1.3 min at 66 degrees C), while the half-life of isolated mutant DN-46 was 540 min at 66 degrees C, i.e., 415-fold more thermostable than mutant F20. The activity of the wild-type and F20 enzymes dropped critically when the pH value was changed to the alkaline range in the absence of NaCl, but no such decrease was apparent with the DN-46 enzyme in the absence of NaCl.

Effects of inhaled furosemide on CO(2) ventilatory responsiveness in humans

We previously showed that inhaled furosemide improves experimentally induced dyspnea. In order to test the possibility that inhaled furosemide may alter the CO(2) chemosensitivity and thereby reduce the dyspneic sensation, the effect of inhaled furosemide on CO(2) chemosensitivity was evaluated with a double-blinded, randomized crossover design in 10 healthy subjects. The CO(2) chemosensitivity was measured by the steady-state and rebreathing methods before and after the inhalation of placebo (normal saline) and furosemide aerosols (40 mg). In addition, subjects were asked to rate their sensation of respiratory discomfort using a visual analog scale (dyspneic VAS) during the measurement of CO(2) chemosensitivity with the steady-state method. Our results showed that (1) inhaled furosemide does not affect the breathing patterns of resting breathing, (2) inhaled furosemide does not affect the slope and intercept of the CO(2) response curve, regardless of whether the CO(2) chemosensitivity is measured by the steady-state technique or rebreathing technique and (3) inhaled furosemide improves the dyspneic sensation produced during hypercapnic hyperpnea. These results suggest that the mechanism of the improvement of dyspnea by inhaling furosemide is not associated with the decrease in the ventilatory drive to CO(2).

Reimplanted ureter as an alternative to the catheterizable Mitrofanoff tube

OBJECTIVE

We performed this study in dogs to investigate whether a ureter can be used as an alternative to the appendix without disrupting the uniformity of the gastrointestinal system.

MATERIALS AND METHODS

This study comprised 10 adult healthy female mongrel dogs. The procedure was done in 2 stages: in the first stage, we performed a left-end cutaneous ureterostomy at the lower left quadrant just above the inguinal ligament. A second operation was performed 6 weeks later. The left ureter was divided and using Paquin's technique, the proximal end of the distal third of the left ureter was reimplanted in the anterolateral surface near the dome of the bladder. A high transureteroureterostomy with the remaining left proximal ureter to the opposite ureter completed the reconstruction. The bladder neck was ligated in order to create an experimental bladder outlet obstruction. At the time of creating the distal ureteral stoma, a feeding tube was left in the bladder, passing through the ureterostomy stoma and sutured to the skin. This catheter remained in place for 20 days, preventing the bladder form distending. Then in the following 6 months, intermittent catheterization was applied through the stoma at 3- to 4-hour intervals. Exploration was performed at the end of the 6th month.

RESULTS

No animal died. The dogs were still continent. Intravenous urography, urea and creatinin values were normal. The ureteral stoma was viable in all 10 cases. Stenosis of the ureteral stoma developed in 1 dog and required surgical revision. Possible traumatic effects were investigated by histological sections, but no harmful effects were found at the ureteral endothelium.

CONCLUSION

This method may be an alternative to the Mitrofanoff method, which uses the appendix.

Establishment of human cementifying fibroma cell lines by transfection with temperature-sensitive simian virus-40 T-antigen gene and hTERT gene

Human cementifying fibroma (HCF) is a benign fibro-osseous neoplasm of periodontal ligament (PDL) origin containing varying amounts of mineralized material resembling cementum. In the present study, we established cell lines from HCF, which were detected in the mandible of a 54-year-old Japanese man. To obtain immortalized cell clones, we undertook transfection with temperature-sensitive simian virus-40 (SV40) T-antigen and hTERT into HCF cells. Cells transfected with SV40 T-antigen entered "crisis" state between passages 22 and 35, but activation of telomerase by transfection with hTERT in the SV40-transformed HCF cells resulted in bypass of the crisis and maintenance over passage 200. HCF cell lines decreased the expression of SV40 T-antigen and the activity of cell proliferation at a nonpermissive temperature (39 degrees C) in comparison with that at a permissive temperature (33 degrees C). High activities of alkaline phosphatase and mineralization and the expression of type I collagen, osteocalcin, osteopontin, and bone sialoprotein by reverse transcription-polymerase chain reaction (RT-PCR) were observed in HCF cells at 39 degrees C. Overall, these findings suggest that: (i) HCF cell lines may represent a novel in vitro human cell model for the study of the regulatory mechanism of differentiation and proliferation of the human PDL; and (ii) transfection of plasmids encoding the temperature-sensitive SV40 T-antigen gene and hTERT gene may be useful for obtaining immortalized cell lines from benign human tumor and, probably, nonneoplastic human tissues.

8-oxo-dGTPase, which prevents oxidative stress-induced DNA damage, increases in the mitochondria from failing hearts

BACKGROUND

Reactive oxygen species (ROS) can cause an oxidative modification of nucleotides, such as 8-oxo-7,8-dihydrodeoxyguanosine triphosphate (8-oxo-dGTP), which can lead to defects in DNA replication. The misincorporation of 8-oxo-dGTP into DNA is prevented by 8-oxo-dGTPase, which hydrolyzes 8-oxo-dGTP into 8-oxo-dGMP. The changes in this defensive system have not yet been examined in failing hearts, in which the generation of ROS increases.

METHODS AND RESULTS

Myocardial infarction (MI) was created in mice by ligating the left coronary artery. Four weeks later, the left ventricle was dilated and contractility was diminished on echocardiography. The generation of ROS, as measured by electron spin resonance spectroscopy with 4-hydroxy-2,2,6,6-tetramethyl-piperidine-N-oxyl, increased in the noninfarcted left ventricle from MI mice. The formation of thiobarbituric acid-reactive substances also increased in the mitochondria from MI mice. 8-Oxo-dGTPase was detected in the mitochondrial fractions isolated from MI mice using a Western blot analysis with an antibody to its human homologue (hMTH1). Immunohistochemistry showed positive staining for hMTH1 was localized in the cardiac myocytes.

CONCLUSIONS

The level of 8-oxo-dGTPase increased in the mitochondria isolated from post-MI hearts as oxidative stress increased, thus suggesting that a preventive mechanism is activated against ROS-induced DNA damage. As a result, 8-oxo-dGTPase is considered a useful marker of mitochondrial oxidative stress in heart failure.

Increased inactivation of nitric oxide is involved in impaired coronary flow reserve in heart failure

Recent evidence suggests that increased inactivation of endothelium-derived nitric oxide (NO) by oxygen free radical (OFR) formation is involved in the pathogenesis of endothelial dysfunction in heart failure (HF). However, it is unclear whether increased OFR limits coronary flow reserve in HF. To test this hypothesis, we examined the effects of antioxidant therapy on coronary flow reserve in a canine model of tachycardia-induced HF. The flow reserve (percent increase in coronary blood flow) to adenosine or to 20-s ischemia was less and OFR formation (electron-spin resonance spectroscopy) in myocardial tissues was greater in HF dogs than in controls. Immunohistochemical staining of 4-hydroxy-2-nonenal, an OFR-induced lipid peroxide, was detected in coronary microvessels of HF dogs. Intracoronary infusion of a cell-permeable OFR scavenger, tiron, suppressed OFR formation and improved the vasodilating capacity to adenosine or brief ischemia in HF dogs but not in controls. A NO synthesis inhibitor, N(G)-monomethyl-L-arginine (L-NMMA), diminished the beneficial effects of tiron in HF dogs. Vasodilation to sodium nitroprusside was similar between control and HF dogs, and no change in its response was noted with tiron or tiron + L-NMMA in either group. In summary, antioxidant treatment with tiron improved coronary flow reserve by increasing NO bioactivity in HF dogs. Thus increased OFR formation may impair coronary flow reserve in HF by reducing NO bioactivity.

Sesamin, a sesame lignan, decreases fatty acid synthesis in rat liver accompanying the down-regulation of sterol regulatory element binding protein-1

The effect of sesamin, one of the most abundant lignans in sesame seed, on hepatic fatty acid synthesis was examined in rats. Rats were fed experimental diets containing varying amounts (0, 0.1 and 0.2% for Exp. 1 and 0, 0.2 and 0.4% for Exp. 2, respectively) of sesamin for 15 days. The activity and gene expression of enzymes involved in fatty acid synthesis including acetyl-CoA carboxylase, fatty acid synthase, ATP-citrate lyase and glucose-6-phosphate dehydrogenase decreased as the dietary level of sesamin increased in Exp. 1 and in rats fed the 0.2% sesamin diet they were approximately one-half those in animals fed a sesamin-free diet. In Exp. 2, the 0.2% sesamin diet lowered these parameters to one-half the level for a sesamin-free diet, but no further reduction was seen in animals fed the 0.4% sesamin diet. Dietary sesamin dose-dependently decreased the sterol regulatory element binding protein-1 (SREBP-1) mRNA level, and the value in rats fed a 0.4% sesamin diet was approximately one-half that in those fed a sesamin-free diet. The protein content of the membrane-bound precursor form of SREBP-1 decreased as dietary sesamin increased and was 37% lower in rats fed the 0.4% sesamin diet than in those fed a sesamin-free diet. Dietary sesamin exerted a more marked influence on the protein content of the mature nuclear form of SREBP-1. Diets containing 0.2 and 0.4% sesamin lowered the amount of mature SREBP-1 protein to less than one-fifth of that in the animals fed a sesamin-free diet. It was suggested that the dietary sesamin-dependent decrease in lipogenic enzyme gene expression is due to the suppression of the gene expression of SREBP-1 as well as the proteolysis of the membrane-bound precursor form of this transcriptional factor to generate the mature form.

The mechanisms by which both heterozygous peroxisome proliferator-activated receptor gamma (PPARgamma) deficiency and PPARgamma agonist improve insulin resistance

Peroxisome proliferator-activated receptor (PPAR) gamma is a ligand-activated transcription factor and a member of the nuclear hormone receptor superfamily that is thought to be the master regulator of fat storage; however, the relationship between PPARgamma and insulin sensitivity is highly controversial. We show here that supraphysiological activation of PPARgamma by PPARgamma agonist thiazolidinediones (TZD) markedly increases triglyceride (TG) content of white adipose tissue (WAT), thereby decreasing TG content of liver and muscle, leading to amelioration of insulin resistance at the expense of obesity. Moderate reduction of PPARgamma activity by heterozygous PPARgamma deficiency decreases TG content of WAT, skeletal muscle, and liver due to increased leptin expression and increase in fatty acid combustion and decrease in lipogenesis, thereby ameliorating high fat diet-induced obesity and insulin resistance. Moreover, although heterozygous PPARgamma deficiency and TZD have opposite effects on total WAT mass, heterozygous PPARgamma deficiency decreases lipogenesis in WAT, whereas TZD stimulate adipocyte differentiation and apoptosis, thereby both preventing adipocyte hypertrophy, which is associated with alleviation of insulin resistance presumably due to decreases in free fatty acids, and tumor necrosis factor alpha, and up-regulation of adiponectin, at least in part. We conclude that, although by different mechanisms, both heterozygous PPARgamma deficiency and PPARgamma agonist improve insulin resistance, which is associated with decreased TG content of muscle/liver and prevention of adipocyte hypertrophy.

Inhaled furosemide inhibits behavioral response to airway occlusion in anesthetized cats

BACKGROUND

A recent study showed that inhaled furosemide greatly improves experimentally induced dyspnea in humans. The objective of the current study is to test the hypothesis that inhaled furosemide suppresses the behavioral response to airway occlusion without changing the behavioral response to a somatic noxious stimulus in anesthetized animals.

METHODS

In 10 spontaneously breathing cats anesthetized with isoflurane, anesthetic ED(50) was determined by measuring an end-tidal anesthetic concentration while observing escape behavior. The monitored behavior consisted of purposeful movement of the head and forearm after endotracheal tube occlusion. The duration from the start of airway occlusion to the onset of the positive response (DOCCL) was measured at the highest concentration of isoflurane permitting the positive motor response to airway occlusion before pretreatment. ED(50) values (minimum alveolar concentration) for the suppression of a somatic motor response to a noxious stimulus induced by toe pinch (toe-pinch ED(50)) were also determined. Then, the effects of inhaled furosemide or vehicle on the ED(50) for the suppression of the behavioral response to airway occlusion, DOCCL, and toe-pinch ED(50) were evaluated in a randomized, cross-over design.

RESULTS

The ED(50) for the suppression of the behavioral response to airway occlusion significantly decreased (P < 0.01) and DOCCL was significantly prolonged (P < 0.01) after furosemide inhalation, whereas vehicle inhalation did not change these measurements. The decrease in ED(50) for the suppression of the behavioral response to airway occlusion after furosemide inhalation lasted 3 h. Furosemide inhalation did not affect the toe-pinch ED(50).

CONCLUSION

Inhaled furosemide suppressed the behavioral response to airway occlusion in anesthetized animals without affecting the response to somatic noxious stimulus. The authors' animal model of respiratory distress may be applicable to the study of dyspnea in regard to its mechanism and treatment.

Dietary mold oil rich in gamma linolenic acid increases insulin-dependent glucose utilization in isolated rat adipocytes

Effects of dietary fats differing in fatty acid composition on insulin-stimulated glucose metabolism in adipocytes isolated from rat white adipose tissue were compared. Rats were fed experimental diets containing various fats differing in fatty acid composition for 7 days. In the first experiment, rats were fed palm oil mainly consisting of palmitic (45.3%) and oleic acids (39.1%) or safflower oil rich in linoleic acid (71.6%). In the second trial, rats were fed palm oil, or a fat mixture rich in linoleic acid or mold oil rich in gamma-linolenic acid. Contents of fatty acids except for linoleic and gamma-linolenic acid were comparable between the fat mixture and mold oil. The former was devoid of gamma-linolenic acid and contained 42.0% linoleic acid, while the latter contained 25.9% gamma-linolenic and 15.7% linoleic acids. In the first experiment, the insulin-dependent increase in glucose oxidation and incorporation into lipids was higher in rats fed safflower oil compared to those fed palm oil. In the second experiment, the insulin-dependent increase in glucose oxidation and incorporation into lipids was higher in rats fed the fat mixture and mold oil than in those fed palm oil. However, the extent of the increase in these parameters was much greater in rats fed mold oil than in those fed the fat mixture. Therefore, dietary gamma-linolenic acid compared to linoleic acid increases glucose metabolism in response to insulin stimuli in isolated rat adipocytes.

Inhibition of RXR and PPARgamma ameliorates diet-induced obesity and type 2 diabetes

PPARgamma is a ligand-activated transcription factor and functions as a heterodimer with a retinoid X receptor (RXR). Supraphysiological activation of PPARgamma by thiazolidinediones can reduce insulin resistance and hyperglycemia in type 2 diabetes, but these drugs can also cause weight gain. Quite unexpectedly, a moderate reduction of PPARgamma activity observed in heterozygous PPARgamma-deficient mice or the Pro12Ala polymorphism in human PPARgamma, has been shown to prevent insulin resistance and obesity induced by a high-fat diet. In this study, we investigated whether functional antagonism toward PPARgamma/RXR could be used to treat obesity and type 2 diabetes. We show herein that an RXR antagonist and a PPARgamma antagonist decrease triglyceride (TG) content in white adipose tissue, skeletal muscle, and liver. These inhibitors potentiated leptin's effects and increased fatty acid combustion and energy dissipation, thereby ameliorating HF diet-induced obesity and insulin resistance. Paradoxically, treatment of heterozygous PPARgamma-deficient mice with an RXR antagonist or a PPARgamma antagonist depletes white adipose tissue and markedly decreases leptin levels and energy dissipation, which increases TG content in skeletal muscle and the liver, thereby leading to the re-emergence of insulin resistance. Our data suggested that appropriate functional antagonism of PPARgamma/RXR may be a logical approach to protection against obesity and related diseases such as type 2 diabetes.

Characterization of translocation pores inserted into plasma membranes by type III-secreted Esp proteins of enteropathogenic Escherichia coli

Many mucosal pathogens use type III secretion systems for the injection of effector proteins into target cells. The type III-secreted proteins EspB and EspD of enteropathogenic Escherichia coli (EPEC) are inserted into the target cell membrane. Together with EspA, these proteins are supposed to constitute a molecular syringe, channelling other effector proteins into the host cell. In this model, EspB and EspD would represent the tip of the needle forming a pore into target cell membranes. Although contact-dependent and Esp-mediated haemolytic activity by EPEC has already been described, the formation of a putative pore resulting in haemolysis has not been demonstrated so far. Here, we show that (i) diffusely adhering (DA)-EPEC strains exhibit a type III-dependent haemolytic activity too; (ii) this activity resides in the secreted proteins and, for DA-EPEC strains, in contrast to EPEC strains, does not require bacterial contact; and (iii) pores are introduced into the target cell membrane. Osmoprotection revealed a minimal pore size of 3-5 nm. The pores induced by type III-secreted proteins of DA-EPEC were characterized by electron microscopy techniques. Analysis by atomic force microscopy demonstrated the pores to be composed of six to eight subunits with a lateral extension of 55-65 nm and to be raised 15-20 nm above the membrane plane. We could also demonstrate an association of EspB and EspD with erythrocyte membranes and an interaction of both proteins with each other in vitro. These results, together with the homologies of EspB and EspD to proposed functional domains of other pore-forming proteins (Yop/Ipa), strongly support the idea that both proteins are directly involved in pore formation, which might represent the type III secretion system translocon.

Transcription-mediated amplification is more useful in the follow-up of patients with chronic hepatitis B treated with lamivudine

Changes in the HBV DNA level during the treatment of patients with chronic hepatitis B with lamivudine were investigated by the transcription-mediated amplification (TMA) assay. Twenty-four patients treated with lamivudine (males:female= 20:4, age: 44.0+/-9.0 years, chronic hepatitis: 14, cirrhosis: 7, cirrhosis with hepatocellular carcinoma: 3) were investigated. The dosage of lamivudine was 75 mg/day in 3, 100 mg/day in 8, and 150 mg/day in 13 patients, and the administration period was 48+/-16 weeks (24-79 weeks). Sixteen patients were HBe antigen-positive before treatment, and the HBV DNA level was 7.4+/-1.2 (4.0- more than 8.7) LGE/ml. The HBV DNA level was measured every 1-6 months by the TMA assay and the branched DNA signal amplification technology (b-DNA assay). Serum HBV DNA disappeared in all patients by the b-DNA during the treatment period, while six patients had persistent HBV DNA by the TMA. The time of HBV DNA disappearance by the TMA in 18 patients was 2-5 months after initiation of treatment. The disappearance rate of HBV DNA was 3/8 (38%) in patients whose HBV DNA level before treatment was 8.0 LGE/ml or higher, 7/8 (88%) in those with 7-7.9 LGE/ml, and 8/8 (100%) in those with 6.9 LGE/ml or lower, showing that disappearance of HBV DNA became difficult when the HBV DNA level before treatment was high (P<0.01). In six patients, the HBV DNA level disappeared once, then increased thereafter. The present findings suggested that these increases in the HBV DNA level were due to an increase of YMDD mutant in three of these six patients, and due to a decrease in the dosage in two patients. In treatment with lamivudine, the TMA assay is more useful for understanding the changes in the HBV DNA level than b-DNA assay.

Clonal chromosomal aberrations accompanied by strong telomerase activity in immortalization of human B-lymphoblastoid cell lines transformed by Epstein-Barr virus

Human B-lymphoblastoid cell lines transformed by Epstein-Barr (EBV-LCLs) are considered to be immortalized, although most of them show a normal diploid karyotype. Recently, we and others have shown that only part of EBV-LCLs is immortalized by developing strong telomerase activity that stabilizes the telomeres. In this study, we investigated the change in karyotypes during immortalization. All the eight immortalized cell lines developed clonal chromosomal aberrations accompanied by the development of strong telomerase activity. Interestingly, abnormal chromosomes were not shared among the immortalized cell lines. These results strongly suggest that chromosomal rearrangements and induction of strong telomerase activity are two events that take place in parallel in the process of immortalization of EBV-LCLs, and indicate that EBV-LCLs are clearly divided into two distinct groups, pre-immortal cell lines mostly with a normal diploid karyotype and post-immortal cell lines with a clonally abnormal karyotype.

The fat-derived hormone adiponectin reverses insulin resistance associated with both lipoatrophy and obesity

Adiponectin is an adipocyte-derived hormone. Recent genome-wide scans have mapped a susceptibility locus for type 2 diabetes and metabolic syndrome to chromosome 3q27, where the gene encoding adiponectin is located. Here we show that decreased expression of adiponectin correlates with insulin resistance in mouse models of altered insulin sensitivity. Adiponectin decreases insulin resistance by decreasing triglyceride content in muscle and liver in obese mice. This effect results from increased expression of molecules involved in both fatty-acid combustion and energy dissipation in muscle. Moreover, insulin resistance in lipoatrophic mice was completely reversed by the combination of physiological doses of adiponectin and leptin, but only partially by either adiponectin or leptin alone. We conclude that decreased adiponectin is implicated in the development of insulin resistance in mouse models of both obesity and lipoatrophy. These data also indicate that the replenishment of adiponectin might provide a novel treatment modality for insulin resistance and type 2 diabetes.

Enhanced generation of reactive oxygen species in the limb skeletal muscles from a murine infarct model of heart failure

BACKGROUND

The generation of reactive oxygen species (ROS) is enhanced in the failing myocardium. We hypothesized that ROS were also increased in the limb skeletal muscles in heart failure. Methods and Results-- Myocardial infarction (MI) was created in mice by ligating the left coronary artery. After 4 weeks, the left ventricle was dilated and contractility was diminished by echocardiography. Left ventricular end-diastolic pressure was elevated after MI in association with an increase in lung weight/body weight and the presence of pleural effusion. The generation of ROS in the limb muscles, including the soleus and gastrocnemius muscles, which were excised after MI, was measured by electron spin resonance spectroscopy with 4-hydroxy-2,2,6,6-tetramethyl-piperidine-N-oxyl (hydroxy-TEMPO). Overall, generation was increased, but it was attenuated in the presence of dimethylthiourea or 4,5-dihydroxy-1,2-benzenedisulfonic disodium salt in the reaction mixture, indicating increased generation of hydroxyl radicals originating from superoxide anion. Thiobarbituric acid-reactive substance formation was also increased in muscles after MI. Mitochondrial complex I and III activities were both decreased after MI, which may have caused the functional uncoupling of the respiratory chain and ROS production. Antioxidant enzyme activities, including superoxide dismutase, catalase, and glutathione peroxidase, were comparable between groups.

CONCLUSIONS

Skeletal muscle in post-MI heart failure expressed an increased amount of ROS in association with ROS-mediated lipid peroxidation. This supports the hypothesis that oxidative stress may cause (at least in part) skeletal muscle dysfunction in heart failure.

Long-term follow-up of interferon-treated chronic hepatitis C and serum hepatic fibrosis markers

BACKGROUND/AIMS

We investigated the clinical application of serum fibrosis markers in a long-term follow-up of patients with chronic hepatitis C treated with interferon-alpha.

METHODOLOGY

This study included 52 patients treated with interferon-alpha (total: 480 MU) for 6 months. They each underwent liver biopsy before and after treatment. Twenty-eight patients who underwent liver biopsy less than 2 years after treatment were classified as group 1, and 24 patients as group 2. The two groups were subdivided into HCV RNA-negative responders and HCV RNA-positive nonresponders. Liver specimens were estimated using grading and staging scores. Serum hyaluronan, PIIIP, and type IV collagen levels were measured before and after treatment.

RESULTS

In the responders of groups 1 and 2, grading score after treatment was significantly decreased compared with that before treatment. Staging score after treatment was significantly improved only in the responders of group 2. In the responders of group 2, serum hyaluronan level was significantly decreased compared with that before treatment. In group 2, the grading score was significantly correlated with serum PIIIP and type IV collagen levels, and the staging score was significantly correlated with only serum hyaluronan level.

CONCLUSIONS

These findings indicate that the serum PIIIP and type IV collagen levels reflect the activity, and serum hyaluronan reflects the degree of fibrosis in liver specimens of HCV RNA-negative patients in a long-term follow-up of patients after interferon-alpha treatment.

Effects of ACE inhibition on left ventricular failure and oxidative stress in Dahl salt-sensitive rats

Dahl salt-sensitive (DS) rats fed high-salt diet exert compensated left ventricular (LV) hypertrophy and eventually develop heart failure. Oxidative stress has been shown to be involved in myocardial remodeling and failure and thus might play an important role in this transition from hypertrophy to failure. We measured the amount of reactive oxygen species (ROS) in the myocardium from DS rats by using electron spin resonance spectroscopy with 4-hydroxy-2,2,6,6-tetramethyl-piperidine-N-oxyl (hydroxy-TEMPO) and also examined the effects of chronic angiotensin-converting enzyme (ACE) inhibition on the transition. We divided DS rats (5 weeks old, 150-200 g) into three groups: low-salt (0.3% NaCl) diet for 10 weeks (LS group), high-salt (8% NaCl) diet for 10 weeks (HS-10+V group), and high-salt diet and cilazapril (10 mg/kg body weight per day) started after 5 weeks of high-salt diet and maintained for 5 weeks (HS-10+Cil group). Systolic blood pressure (mm Hg) was significantly elevated in the HS-10+V (229+/-5) and HS-10+Cil (209+/-5) groups compared with the LS group (141+/-2). The amount of myocardial ROS was not changed after 5 weeks of high-salt diet, but significantly increased in HS-10+V rats compared with LS rats, and was abolished in the HS-10+Cil group. HS-10+V rats exerted the clinical signs of heart failure, including increased lung weight and pleural effusion, associated with LV hypertrophy and LV cavity dilatation. In the HS-10+Cil group, signs of heart failure were significantly attenuated despite only a modest reduction in systolic blood pressure (-20 mm Hg). The progression of LV failure after hypertrophy in high-salt-loaded DS hypertensive rats was associated with increased myocardial ROS, and ACE inhibitor could prevent this transition from compensated hypertrophy to failure.

Effect of sesame seeds rich in sesamin and sesamolin on fatty acid oxidation in rat liver

Activities of enzymes involved in hepatic fatty acid oxidation and synthesis among rats fed sesame (Sesamum indicum L.) differing in lignan content (sesamin and sesamolin) were compared. Sesame seeds rich in lignans from two lines, 0730 and 0732, lines established in this laborary, and those from a conventional cultivar (Masekin) were employed. Seeds from the 0730 and 0732 lines contained sesamin and sesamolin at amounts twice those from Masekin. Sesame seeds were added at levels of 200 g/kg to the experimental diets. Sesame increased both the hepatic mitochondrial and the peroxisomal fatty acid oxidation rate. Increases were greater with sesame rich in lignans than with Maskin. Noticeably, peroxisomal activity levels were >3 times higher in rats fed diets containing sesame seeds from the 0730 and 0732 lines than in those fed a control diet without sesame. The diet containing Masekin seed caused only a 50% increase in the value, however. Diets containing seeds from the 0730 and 0732 lines, compared to the control and Masekin diets, also significantly increased the activity of hepatic fatty acid oxidation enzymes including acyl-CoA oxidase, carnitine palmitoyltranferase, 3-hydroxyacyl-CoA dehydrogenase, and 3-ketoacyl-CoA thiolase. In contrast, diets containing sesame lowered the activity of enzymes involved in fatty acid synthesis including fatty acid synthase, glucose-6-phosphate dehydrogenase, ATP-citrate lyase, and pyruvate kinase. No significant differences in enzyme activities were, however, seen among diets containing sesame from Masekin cultivar and lines 0730 and 0732. Serum triacylglycerol concentrations were lower in rats fed diets containing sesame from lines 0730 and 0732 than in those fed the control or Masekin diet. It is apparent that sesame rich in lignans more profoundly affects hepatic fatty acid oxidation and serum triacylglycerol levels. Therefore, consumption of sesame rich in lignans results in physiological activity to alter lipid metabolism in a potentially beneficial manner.

Detection of YMDD motif mutations in some lamivudine-untreated asymptomatic hepatitis B virus carriers

BACKGROUND/AIM

It is well documented that long-term lamivudine treatment induces emergence of lamivudine-resistant hepatitis B virus (HBV), namely, YMDD motif mutation in some patients chronically infected with HBV. We previously reported that there were no YMDD mutant viruses in patients with chronic hepatitis B who were not treated with lamivudine. In this series, we examined mutations in the YMDD motif gene in asymptomatic carriers who maintained normal ALT values for 1 year or more.

METHODS

Serum samples obtained from 18 patients chronically infected with HBV who consulted our university were used. None of these patients had any experience of using antiviral agents. For detection of mutant viruses, a kit developed in our laboratory was used.

RESULTS

Mutations were detected in five of 18 samples: YMDD+YIDD in three samples and YMDD+YVDD+YIDD in two samples. All of these five samples were positive for anit-HBe. In five samples in which mutations were observed, sequencing was carried out following subcloning.

CONCLUSION

The present study demonstrates that YMDD mutant viruses are present in lamivudine-untreated asymptomatic hepatitis B virus carriers as well.

Mitochondrial DNA damage and dysfunction associated with oxidative stress in failing hearts after myocardial infarction

Mitochondria are one of the enzymatic sources of reactive oxygen species (ROS) and could also be a major target for ROS-mediated damage. We hypothesized that ROS may induce mitochondrial DNA (mtDNA) damage, which leads to defects of mtDNA-encoded gene expression and respiratory chain complex enzymes and thus may contribute to the progression of left ventricular (LV) remodeling and failure after myocardial infarction (MI). In a murine model of MI and remodeling created by the left anterior descending coronary artery ligation for 4 weeks, the LV was dilated and contractility was diminished. Hydroxyl radicals, which originated from the superoxide anion, and lipid peroxide formation in the mitochondria were both increased in the noninfarcted LV from MI mice. The mtDNA copy number relative to the nuclear gene (18S rRNA) preferentially decreased by 44% in MI by a Southern blot analysis, associated with a parallel decrease (30% to 50% of sham) in the mtDNA-encoded gene transcripts, including the subunits of complex I (ND1, 2, 3, 4, 4L, and 5), complex III (cytochrome b), complex IV (cytochrome c oxidase), and rRNA (12S and 16S). Consistent with these molecular changes, the enzymatic activity of complexes I, III, and IV decreased in MI, whereas, in contrast, complex II and citrate synthase, encoded only by nuclear DNA, both remained at normal levels. An intimate link among ROS, mtDNA damage, and defects in the electron transport function, which may lead to an additional generation of ROS, might play an important role in the development and progression of LV remodeling and failure.