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Biomedical subjects

K Moriya

Publications and source records attributed to K Moriya.

At least 19 recordsLinked to original sources
PubMed2002

Cardiac rhythms in prenatal and perinatal emu embryos.

Emu eggs weigh approximately 600 g and have an incubation duration (ID) of approximately 50 days. The egg mass is approximately 10-fold heavier than the chicken egg and the ID is approximately 2.5-fold longer. Daily changes in mean heart rate (MHR) of emu embryos were previously determined, but further measurement was needed to investigate the species-specific behavior of cardiac rhythm for comparison with other species. In the present study, we continuously measured the electrocardiogram of emu embryos while maintaining adequate gas exchange through the eggshell and determined instantaneous heart rate (IHR) during the last 2-7 days of incubation until hatching or death. The MHR over 1-min intervals was calculated from IHR data in order to present continuous developmental patterns of heart rate (HR) in a single graph and 24-h recordings of HR in a single panel, showing the HR trend over a prolonged period. However, neither circadian nor ultradian rhythms of HR were shown in these figures or by power spectrum analysis. The IHR distinctively fluctuated and the fluctuations were mainly comprised of three patterns of irregular HR accelerations in embryos that hatched. Respiratory sinus arrhythmia also occurred in perinatal embryos. During the final stages of the perinatal period, short-term, repeated, large accelerations of IHR appeared, which signaled imminent hatching and has been reported for chick embryos. IHR fluctuations in embryos that failed to hatch tended to become inactive towards death.

Animals↗
PubMed2002

Cardiac rhythms in developing emu hatchlings.

Six emu hatchlings were non-invasively measured for electrocardiogram (ECG) from their chest wall using flexible electrodes, and the instantaneous heart rate (IHR) was determined from ECG throughout the first week of post-hatching life. Although the baseline heart rate (HR) was low, approximately 100-200 beats per min (bpm), compared with chick hatchlings, the IHR fluctuated markedly. The fluctuation of IHR comprised HR variability and irregularities that were designated as types I, II and III in chick hatchlings and additional large accelerations distinctive of emu hatchlings. Type I was HR oscillation with a mean frequency of 0.37 Hz (range 0.2-0.7 Hz), i.e. respiratory sinus arrhythmia (RSA). From RSA, breathing frequency in emu hatchlings was estimated to be approximately half of that in chickens. Type II HR oscillation was also found in the emu; the frequency ranged from approximately 0.04 to 0.1 with a mean of 0.06 Hz, and the magnitude tended to be large compared with that of chickens. In addition to type III HRI, which was designated in chickens, large, irregular HR accelerations were characteristic of emu hatchlings. From IHR data, developmental patterns of mean heart rate (MHR) were constructed and plotted on a single graph to inspect the diurnal rhythm of MHR by visual inspection and power spectrum analysis. A circadian rhythm was not clear in the emu hatchlings, in contrast to chick hatchlings, which showed a dominant diurnal rhythm.

Animals↗
PubMed2002

Development of respiratory rhythms in perinatal chick embryos.

In chick embryos, gas exchange takes place via the chorioallantoic membrane (CAM) and the lungs at approximately 1 day prior to hatching. The present study was designed to elucidate the development of respiratory rhythms in the chick embryo during the whole pipping (perinatal) period with a condenser-microphone measuring system. The microphone was hermetically attached on the eggshell over the air cell on day 18 of incubation. It first detected a cardiogenic signal (i.e. acoustocardiogram), and then beak clapping and breathing signals (acoustorespirogram, ARG). The first signals of lung ventilation appeared intermittently and irregularly approximately once per 5 s among the clapping signals after the embryo penetrated its beak into the air cell (internal pipping, IP). The respiratory rhythm then developed irregularly, with a subsequent more regular rate. The envelope pattern of breathing from the onset of IP through external pipping (EP) to hatching was constructed by a specially devised procedure, which eliminated external and internal noises. The envelope patterns indicated that the IP, EP and whole perinatal periods of 10 embryos were 14.1+/-6.4 (S.D.), 13.6+/-4.0 and 27.6+/-5.4 h, respectively. In addition, they also indicated the period of embryonic hatching activity (i.e. climax) which was 48+/-19 min. The development of respiratory rhythm was also shown by the instantaneous respiratory rate (IRR) which was designated as an inverse value of two adjacent ARG waves.

Animals↗
PubMed2002

Distribution of emm genotypes and superantigen genes of Streptococcus pyogenes isolated in Japan, 1994-9.

The purpose of this study was to examine characteristic profiles of Streptococcus pyogenes clinical isolates isolated in Japan during 1994-9. Genotyping of the M protein (emm typing) revealed that emm types 12 and 28 were the most common among 316 isolates. Most of the emm12 isolates were isolated from mucosa, while emm58 and emm89 were from skin. Moreover, the emm3 isolates were dominant in invasive infections. The distribution of 6 superantigen genes showed that all isolates harboured the mf gene and many had the speG gene. Invasive isolates were shown to have the ssa gene at a higher rate (76%) than noninvasive (37%). The distribution of superantigens was significantly different between emm types, but not between isolation sites. These results suggest that the distribution of emm types is related to isolation site, whereas superantigen distribution is related to clinical features of S. pyogenes infections.

Antigens, Bacterial↗
PubMed2001

Oxidative stress in the absence of inflammation in a mouse model for hepatitis C virus-associated hepatocarcinogenesis.

The mechanism of hepatocarcinogenesis in hepatitis C virus (HCV) infection is still undefined. One possibility is the involvement of oxidative stress, which can produce genetic mutations as well as gross chromosomal alterations and contribute to cancer development. We recently showed that after a long period, the core protein of HCV induces hepatocellular carcinoma (HCC) in transgenic mice with marked hepatic steatosis but without inflammation, indicating a direct involvement of HCV in hepatocarcinogenesis. To elucidate the biochemical events before the development of HCC, we examined several parameters of oxidative stress and redox homeostasis in a mouse model of HCV-associated HCC. For young mice ages 3-12 months, there was no significant difference in the levels of hydroperoxides of phosphatidylcholine (PCOOH) and phosphatidylethanolamine in liver tissue homogenates between transgenic and nontransgenic control mice. In contrast, the PCOOH level was increased by 180% in old core gene transgenic mice > 16 months old. Concurrently, there was a significant increase in the catalase activity, and there were decreases in the levels of total and reduced glutathione in the same mice. A direct in situ determination by chemiluminescence revealed an increase in hydroperoxide products by 170% even in young transgenic mice, suggesting that hydroperoxides were overproduced but immediately removed by an activated scavenger system in young mice. Electron microscopy revealed lipofuscin granules, secondary lysosomes carrying various cytoplasmic organelles, and disruption of the double membrane structure of mitochondria, and PCR analysis disclosed a deletion in mitochondrial DNA. Interestingly, alcohol caused a marked increase in the PCOOH level in transgenic mice, suggesting synergism between alcohol and HCV in hepatocarcinogenesis. The HCV core protein thus alters the oxidant/antioxidant state in the liver in the absence of inflammation and may thereby contribute to or facilitate, at least in part, the development of HCC in HCV infection.

Animals↗
PubMed2001

Frequent beta-catenin aberration in human hepatocellular carcinoma.

Recently, mutations in the beta-catenin gene in hepatocellular carcinoma (HCC) have been reported: approximately 20% of HCCs had activating mutations at the glycogen synthase kinase 3beta phosphorylation sites within the exon 3 of the beta-catenin gene. However, changes in the level of the beta-catenin protein in HCC have not been well studied. We examined, by Western blotting, the expression level of the beta-catenin protein in cancerous tissues in comparison with that in adjacent non-cancerous tissues obtained from 32 cases of HCC with hepatitis C. An increase in the beta-catenin protein level in cancerous tissue compared to that in adjacent non-cancerous tissue was found in 15 (46.9%) of 32 cases of HCC. Mutation in exon 3 of the beta-catenin gene was found in six (18.8%) of the 32 cases, in five of which the beta-catenin protein level was increased. In total, beta-catenin aberration was found in 16 (50.0%) of 32 cases of HCC. It should be noted that beta-catenin aberration was also found in early HCC although it was observed chiefly in advanced HCCs. These results indicate that beta-catenin aberration is a frequent event in the development of HCC and may facilitate the development of HCC in the course of chronic hepatitis.

Journal Article↗
PubMed2001

Increase in the concentration of carbon 18 monounsaturated fatty acids in the liver with hepatitis C: analysis in transgenic mice and humans.

Steatosis is one of the histologic characteristics of chronic hepatitis C and is well reproduced in a transgenic mouse model for hepatocellular carcinoma (HCC) in which the core protein of hepatitis C virus (HCV) plays a pivotal role in inducing steatosis and HCC. In the present study, the lipid composition in the liver of the HCV core gene transgenic mice as well as in those of chronic hepatitis C patients was determined. The concentration of carbon 18 monounsaturated (C18:1) fatty acids, such as oleic and vaccenic acids, which are known to increase membrane fluidity leading to higher cell division rates, significantly increased in the livers of transgenic mice compared to nontransgenic control mice. The concentration of C18:1 fatty acids also significantly increased in the livers of chronic hepatitis C patients compared to subjects without HCV infection. These results suggest that HCV may affect a specific pathway in the lipid metabolism and cause steatosis in the liver.

Animals↗
PubMed2001

Frequent presence of HBV in the sera of HBsAg-negative, anti-HBc-positive blood donors.

BACKGROUND: Recent studies have revealed that HBV may not be cleared even after the disappearance of serum HBsAg. The purpose of this study was to investigate whether the replication of HBV persists in HBsAg-negative blood donors who lack apparent liver disease. STUDY DESIGN AND METHODS: Serum HBV was examined by using PCR coupled with Southern blotting in 50 blood donors who were identified to be HBsAg negative but anti-HBc positive. RESULTS: HBV DNA was detected in the sera from 19 (38%) of 50 donors. In 11 of the 19, HBV existed exclusively as immune complexes, while HBV presumably did not exist as immune complexes in the remaining eight. The levels of HBV DNA were similar to those in patients who had recovered from acute HBV. Some nucleotide substitutions, which did not confer amino acid changes in the major epitope of HBsAg, were found in the preS-S regions. CONCLUSION: The replication of HBV is ongoing in a substantial proportion of healthy blood donors who have anti-HBc. Blood from such donors may contain very low levels of HBV free of immune complex formation and should be excluded for transfusion. The fact that such blood donors apparently lacked liver disease suggests no pathogenicity of such "occult" HBV.

Adult↗
PubMed2001

Pulpal response to exposure with Er:YAG laser.

OBJECTIVE: The purpose of this study was to evaluate the pulpal response to the Er:YAG laser after accidental exposure of the pulp. STUDY DESIGN: Cavities were prepared, and pulps were exposed by either Er:YAG laser or mechanically by a slow-speed conventional handpiece (control group) in 76 maxillary first molars of male Wistar rats. Rats were killed immediately, at 3 days, 1 week, and 2 weeks. Histopathologic examinations of the pulp at the exposure site were performed and evaluated with the Mann-Whitney U test (P <.05). RESULTS: The Er:YAG laser group showed no bleeding and no dentin chips at the exposure site immediately after pulp exposure. However, they displayed an area of blood extravasation near the exposure site. Subsequently, the Er:YAG laser group formed dentin bridges at the exposure site more frequently than the control group. The Er:YAG laser group demonstrated more reparative dentin formation near the exposure site than the control group, especially at 2 weeks, which was highly significant (P <.01). CONCLUSION: According to the results of this study, Er:YAG laser-exposed pulp tissue demonstrated good healing capacity with the formation of a dentin bridge and reparative dentin. However, further investigations are suggested to study the effect of the blood extravasation, which appeared near the laser exposure sites.

Aluminum Silicates↗
PubMed2001

Computer image analysis for prediction of carcass composition from cross-sections of Japanese Black steers.

Carcasses from Japanese Black steers were used to obtain prediction equations for carcass composition from information derived by computer image analysis of carcass cross-section images. The total weights of lean, fat, and bone were obtained from the left sides of 55 carcasses (Data Set I) and 18 carcasses (Data Set II) by physical dissection. The information such as total lean, fat, and bone areas in the cross-sections; muscle area, muscle circumference, short and long radius axis lengths, and direction of long radius axis; and geometric distance between any two muscle centers of gravity was obtained by scanning and image analysis of pictures of the cross-sections of the beef side at the 6th/7th rib interface. The coefficients of determination of the multiple regression equations estimated from Data Set I for kilograms of lean, fat, and bone were 0.76, 0.82, and 0.69, respectively, whereas for the percentages of lean, fat, and bone they were 0.57, 0.66, and 0.42, respectively. The multiple regression equations from Data Set I was applied to Data Set II in order to test the applicability of the prediction equations obtained. The correlation coefficients between the value predicted by the multiple regression equation and the measurement obtained by physical dissection for kilograms of lean, fat, and bone were 0.71, 0.72, and 0.70, respectively, whereas those for the percentages of lean, fat, and bone were 0.63, 0.44, and 0.29, respectively. The results indicate that the information obtained from the carcass cross-sections by the computer image analysis method can be used to predict carcass composition in Japanese Black steers.

Adipose Tissue↗
PubMed2000

Detection and characterization of a 36-kDa peptide in C-terminal region of a 24-kDa vacuolar protein (VP24) precursor in anthocyanin-producing sweet potato cells in suspension culture.

A 24-kDa vacuolar protein (VP24) was found to accumulate in anthocyanin-producing sweet potato cells (Ipomoea batatas Lam.) in suspension culture [Nozue et al., Plant Physiol. 115 (1997) 1065]. VP24 cDNA (accession No. AB025531) encodes a 96.3-kDa large precursor protein with a C-terminal propeptide which contains the eight putative transmembrane domains. The mature VP24 is probably involved in the formation of intravacuolar pigmented globules (cyanoplasts) in highly anthocyanin-containing vacuoles, but the biological function of the C-terminal region including the putative transmembrane domains is unknown. To confirm the expression and characterize the C-terminal region in the VP24 protein precursor in the anthocyanin-producing cells, polyclonal antibodies were developed against the fusion protein, including the C-terminal region, expressed in Escherichia coli. Western blot analysis showed that a 36-kDa peptide (VP36) localized in anthocyanin-containing vacuoles was expressed under continuous illumination, but not in darkness. The expression pattern of VP36 showed high similarity to VP24. These results suggested that VP36 may be derived from the large VP24 protein precursor; it includes several of the hydrophobic domains in the C-terminal region.

Journal Article↗
PubMed2000

The significance of hepatitis B virus DNA detected in hepatocellular carcinoma of patients with hepatitis C.

BACKGROUND: Recently, it has been reported that hepatitis B virus (HBV) DNA is detected in cancerous liver tissues in some hepatitis B surface antigen negative chronic hepatitis C patients with hepatocellular carcinoma (HCC). However, the significance of HBV DNA detected in such cases remains unclear. METHODS: The authors determined the presence or absence and the titers of HBV DNA in the liver tissue of anti-hepatitis C virus (HCV) positive/HBs antigen negative patients with HCC by polymerase chain reaction (PCR) and Southern hybridization, and correlated them with clinicopathologic parameters. RESULTS: HBV DNA was found in cancerous liver tissues from 12 (50.0%) of the 24 patients studied. However, Southern hybridization of genomic DNA in the cancerous liver tissues led to detection of HBV DNA in only 3 (12.5%) of the 24 patients, suggesting that the copy number of HBV DNA may be very low in most cases. Indeed, the titration of HBV DNA in cancerous liver tissues performed by the end point dilution method revealed that most contained less than one copy of HBV DNA per cell, although cells of monoclonal origin carrying integrated HBV DNA should have at least one copy of it. There was no significant difference in HBV DNA positivity between the HCC patients with and without underlying cirrhosis. CONCLUSIONS: The results of this study corroborate previous reports of frequent detection of HBV DNA in the liver tissue of anti-HCV positive/HBs antigen negative patients with HCC, but do not support an essential role of HBV in hepatocarcinogenesis in patients with chronic hepatitis C and occult HBV infection.

Aged↗
PubMed2000

Virologic analysis of non-B, non-C hepatocellular carcinoma in Japan: frequent involvement of hepatitis B virus.

Serum and liver tissues from hepatitis B surface antigen-negative/anti-hepatitis C virus (HCV)-negative (non-B, non-C) hepatocellular carcinoma (HCC) patients in Japan were examined for the presence of hepatitis B virus (HBV), HCV, and TT virus (TTV) by polymerase chain reaction. The studies evaluated the contribution of these viruses to pathogenesis of HCC. HBV DNA was detected in the sera of 20 (47.6%) of 42 non-B, non-C HCC patients, which was significantly higher than in age-matched controls without liver disease (P<.001). In 8 of 12 patients with liver tissues available, HBV DNA was detected in cancerous and adjacent noncancerous liver tissues. No HCV RNA was detected. The positivity for TTV DNA was not significantly different between HCC patients and controls. These results indicate that HBV is associated with a substantial proportion of non-B, non-C HCC cases in Japan. The role of HBV in hepatocarcinogenesis in such patients needs to be clarified.

Adult↗
PubMed2000

Development and regulation of heart rate in embryos and hatchlings of gulls (Larus schistisagus and Larus crassirostris) in relation to growth.

We compared the developmental patterns of mean heart rate in Larus crassirostris and L. schistisagus embryos and chicks with other avian species of different hatchling developmental modes. We proposed that, since mean heart rate is inversely related to fresh egg mass in all birds, larger species reached a higher fraction of their hatchling mean heart rate by the end of the early phase of incubation and that heart rate contributions to supplying the increasing metabolic demands during mid and late incubation phases were less important than in smaller avian species. Mean heart rate was essentially independent of age throughout the mid-incubation phase (33% of normalised incubation until pipping), but increased with time during early (L. schistisagus only investigated) and late-incubation phases in both species. The O2 pulse of L. schistisagus embryos and chicks increased linearly with yolk-free body mass (log-log) after the early-phase of incubation until shortly before pipping, but was independent of body mass in the periods before and after. We conclude that a high heart rate in this first period is probably more important for increasing the circulation of nutrients to the embryo at a stage when extra-embryonic circulation to the yolk sac is limited by the size of the growing area vaculosa. Furthermore, large increases in mean heart rate during the late-incubation phase are probably important for increasing the cardiac output to hatching levels with onset of endothermy. However, mean heart rate is stable over the mid-incubation while O2 pulse increases, suggesting that increases in stroke volume and other circulatory adjustments may be entirely responsible for the largest increases in O2 transport during incubation of large avian species.

Animals↗
PubMed2000

Glycosylated human interleukin-1alpha, neoglyco IL-1alpha, coupled with N-acetylneuraminic acid exhibits selective activities in vivo and altered tissue distribution.

In order to study the effect of glycosylation on its biological activities and to develop IL-1 with less deleterious effects, N-acetylneuraminic acid (NeuAc) with C9 spacer was chemically coupled to human recombinant IL-1alpha. NeuAc-coupled IL-1alpha (NeuAc-IL-1alpha) exhibited reduced activities in vitro and receptor-binding affinities by about ten times compared to IL-1alpha. In this study, we examined a variety of IL-1 activities in vivo. NeuAc-IL-1alpha exhibited a marked reduction in the activity to up-regulate serum IL-6, moderate reduction in the activities to up-regulate serum amyloid A and NOx. However, it exhibited comparable activities as IL-1alpha to down-regulate serum glucose and to improve the recovery of peripheral white blood cells from myelosuppression in 5-fluorouracil-treated mice. In addition, tissue level of NeuAc-IL-1alpha was high compared to IL-1alpha. These results indicate that coupling with NeuAc enabled us to develop neo-IL-1 with selective activities in vivo and enhanced tissue level.

Animals↗
PubMed2000

Embryonic heart rate measurements during artificial incubation of emu eggs.

1. Daily changes in embryonic heart rate (HR) of emu were determined non-invasively at 36 degrees C by acoustocardiography (ACG) during the last 30% of artificial incubation (predicted incubation time is 50 d). 2. The pattern of daily changes in mean HR of hatched embryos decreased from about 175 bpm to about 140 bpm towards the end of incubation. 3. The mean HR at 80% of incubation (ca. 170 bpm) was close to the value predicted from an allometric equation reported previously for precocial domesticated birds. 4. ACG could measure embryonic HR even during the external pipping period. 5. If the artificial external pipping procedure is timed correctly after internal pipping, it might aid the embryos in hatching. However, further investigation into this aspect is needed.

Animals↗