Biomedical subjects

M Kadowaki

Publications and source records attributed to M Kadowaki.

At least 19 recordsLinked to original sources

PubMed2006

Gene expression of myostatin during development and regeneration of skeletal muscle in Japanese Black Cattle.

Myostatin is a specific negative regulator of skeletal muscle growth and is regarded as one of the most important factors for myogenesis. The aim of the current study was to analyze the developmental change in the gene expression of myostatin and an adipogenic transcription factor (peroxisome proliferator-activated receptor lambda2) in the semitendinosus muscle of Japanese Black Cattle throughout the whole life cycle. An additional aim was to compare the temporal expression patterns of myostatin and relevant myogenic regulatory factors (MRF) mRNA during muscle regeneration after frostbite injury at 16 mo of age. The developmental pattern of myostatin gene expression exhibited 2 peaks: the greatest expression occurred in utero (P <0.05) and the second greatest occurred at 16 mo of age (P <0.05). The greatest level of peroxisome proliferator-activated receptor lambda2 expression was observed at 16 mo of age (P <0.05), which paralleled myostatin expression. During frostbite-induced muscle regeneration, gene expression for myostatin and 4 MRF; i.e., Myf5, MyoD, myogenin and MRF4, showed contrasting responses. Myostatin mRNA dramatically declined by 68.1 and 82.6% at 3 and 5 d after injury (P <0.05), respectively, which paralleled its protein expression, and was restored at 10 d. In contrast, the expressions of all 4 MRF mRNA were low initially but increased by 5 d after injury (P <0.05) and then remained constant or decreased slightly. These results suggest that myostatin may play a role in muscle marbling in the fattening period by decreasing myogenesis and increasing adipogenesis, and that the interaction between myostatin and MRF genes may take place at an early stage of skeletal muscle regeneration.

Animals↗

PubMed2001

Enhanced colonic peristalsis by impairment of nitrergic enteric neurons in spontaneously diabetic rats.

Changes in enteric neurons containing various neurotransmitters in the colon have been described in diabetic rats; however, how these changes are related to colonic motility disorders remains unclear. Nitric oxide (NO) is known to be an important inhibitory neurotransmitter in the enteric nervous system. In the present study, we investigated the peristaltic reflex using our modified Trendelenburg's method to evaluate the differences in enteric nitrergic neurons of the distal colon between spontaneously diabetic rats and their sibling control rats. We measured maximum intraluminal pressure, threshold pressure and propagation distance of the reflex contraction. These diabetic rats showed a greater maximum intraluminal pressure than that in the control rats. NG nitro-L-arginine methyl ester (L-NAME) significantly increased the maximum pressure in the control rats. Although L-arginine did not change the maximum pressure, sodium nitroprusside (SNP) significantly decreased it in these diabetic rats. Nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase reactivities in the myenteric plexus were much weaker in the diabetic rats than those in the control rats. These results indicate that the colonic peristaltic reflex is enhanced by impairment of enteric nitrergic inhibitory neurons in spontaneously diabetic rats.

Animals↗

PubMed2001

A remnant tubal pregnancy after cloacal malformation repair.

OBJECTIVE: Report of a remnant tubal pregnancy after cloacal malformation repair. DESIGN: Case report. SETTING: A university hospital. PATIENT: A woman with cloacal malformation repair. INTERVENTION: Laparoscopic surgery. MAIN OUTCOME MEASURE: Remnant tubal pregnancy. RESULT: Laparoscopic right salpingectomy. CONCLUSION(S): In this patient, ectopic pregnancy was caused by contralateral sperm transmigration to the remnant right tube, which was not connected with the left uterus.

Adult↗

PubMed2001

Leupeptin-induced appearance of partial fragment of betaine homocysteine methyltransferase during autophagic maturation in rat hepatocytes.

A cytosolic enzyme, betaine homocysteine methyltransferase (BHMT), and its partial fragments were discovered as autolysosomal membrane proteins from rat liver in the presence of leupeptin [Ueno et al. (1999) J. Biol. Chem. 274, 15222-15229]. The present study was undertaken to further characterize the transport and processing of BHMT from cytosol to autolysosome and to test if the fragment can be used as an in vitro probe for the maturation step of macroautophagy. Upon subcellular fractionation, BHMT (p44) was found in all fractions, while its 32-kDa fragment (p32) was found only in the mitochondrial-lysosomal (ML) fraction. Incubation of isolated hepatocytes with leupeptin induced time-dependent accumulation of p32 in the ML fraction from 30 to 90 min after the start of incubation. However, chloroquine completely inhibited the appearance of p32, indicating that the processing from p44 to p32 is lysosomal. Incubation with Bafilomycin A(1), a vacuolar H(+)-ATPase inhibitor, together with leupeptin, led to linear accumulation of p44, but not of p32. The p44 accumulation rate was calculated to be 4.9%/h, which was comparable to autophagic sequestration rate. The distribution of p44 within the ML fraction turned out to be dual, i.e., the membrane-surface attached and luminal/sedimentable forms. Amino acids and 3-methyladenine, both of which specifically suppress macroautophagy, inhibited the accumulation of p32 as well as of p44. Finally, energy-dependent appearance of p32 was demonstrated during incubation of postnucler supernatant fractions, making it possible to establish an in vitro assay system. All the results strongly support the idea that BHMT is taken up and degraded to p32 through the macroautophagic pathway, and that p32 could be a novel probe for the maturation of macroautophagy.

Animals↗

PubMed2001

Natto mucilage containing poly-gamma-glutamic acid increases soluble calcium in the rat small intestine.

We prepared natto (fermented soybeans) mucilage containing poly-gamma-glutamic acid (gamma-PGA) from commercial natto. The effect of natto mucilage on calcium (Ca) solubility in vitro and in vivo was investigated. Ca solubility in vitro increased with an increase in the amount of natto mucilage, due to inhibition of the formation of an insoluble complex of Ca with phosphate by natto mucilage. Rats were fed with 5 g of soybean protein isolate, natto, mucilage-free natto, or natto mucilage diet for 1.5 h. Small intestinal contents were collected 2.5 h after ingestion. In the lower half of the small intestine, both the amount and the percentage of soluble Ca of intestinal contents were significantly higher (P < 0.001) in rats fed with natto mucilage diet than in those fed with the other diets. Natto mucilage also increased Ca solubility in vivo. These results suggested that gamma-PGA is responsible for the increasing effect of natto mucilage on Ca solubility.

Animals↗

PubMed2001

Rhythmic spontaneous contractions in the rat proximal colon.

C-kit immunoreactive cells are known to be interstitial cells of Cajal (ICCs), and they generate pacemaker activity of the gastrointestinal tract. Recently a large number of special smooth muscle cells corresponding to c-kit immunoreactive cells were found in the proximal colon of the guinea pig. We learned that the rat proximal colon showed tetrodotoxin-insensitive regular rhythmic spontaneous contractions (RSCs) and hypothesized that RSCs are generated and/or regulated by ICCs. To prove our hypothesis, we investigated whether RSCs are absent in homozygous Ws/Ws mutant rats, since c-kit positive ICCs along the submucosal surface of the circular muscle (ICC(SM)) and myenteric plexus (ICC(MY)) are lacking. In contrast to our hypothesis, we found that RSCs were still present in the proximal colon of the Ws/Ws mutant rats. A recent study has reported that c-kit negative ICC(SM) remains in Ws/Ws mutant rats. Taken together, RSCs may be generated by c-kit negative ICC(SM) in the rat proximal colon. The blockade of sarcoplasmic reticulum Ca(2+)-ATPase by cyclopiazonic acid (CPA) (10(-6)M) or by thapsigargin (10(-6)M) increased the frequency of RSCs. The increasing effects of CPA on the frequency of RSCs were more prominent in Ws/Ws mutant rats than in +/+ rats. We concluded that the functional coordination between c-kit negative ICC(SM) and other mutationally impaired c-kit positive ICC(MY) and ICC(SM) may be required for moderate regulation in the frequency of spontaneous activity.

Animals↗

PubMed2000

Nociceptin inhibits capsaicin-sensitive contraction to mesenteric nerve stimulation in the guinea-pig isolated ileum.

Mesenteric nerve stimulation (MNS) in the presence of guanethidine and hexamethonium antidromically stimulated extrinsic sensory nerve fibers and cholinergic myenteric motor neurons, resulting in longitudinal muscle contraction in the isolated guinea-pig ileum. Nociceptin (NC) is a recently discovered neuropeptide that structurally resembles an opioid peptide. The aim of the current study was to examine how NC affects the contractile responses to MNS in the isolated guinea-pig ileum, in comparison with an opiate, methionine-enkephalin. These contractions were auxotonically recorded and their amplitude was analyzed. NC (1-100 nM) and methionine-enkephalin (0.1-10 microM) concentration-dependently inhibited the response to MNS (20 Hz, 0.5 ms, supramaximal currents). Naloxone (10 microM) significantly diminished the inhibitory effect of methionine-enkephalin (0.1-10 microM), but did not antagonize the inhibitory effect of NC (1-100 nM). We conclude that NC receptors, distinct from opioid receptors, exist on the capsaicin-sensitive sensory nerve fibers and/or myenteric cholinergic motor neurons in the guinea-pig ileum and that specific antagonists for these NC receptors are not found yet.

Animals↗

PubMed2000

Adenosine A1 receptor blockade reverses dysmotility induced by ischemia-reperfusion in rat colon.

This study was designed to assess whether adenosine A1 receptor antagonists [(R)-1-[(E)-3-(2-phenylpyrazolo[1,5-a]pyridin-3-yl) acryloyl]-piperidin-2-yl acetic acid (FK352) and 8-cyclopentyl-1,3-dipropylxanthine (DPCPX)] reverse dysmotility induced by ischemia-reperfusion in the rat colon. The gene of adenosine A1 receptor was expressed in the colon. Clamping (30 min) of the colonic marginal vessels was followed by reperfusion, and the propulsive colonic motility was evaluated. Propulsion was significantly slowed by ischemia-reperfusion, while FK352 and DPCPX abolished this delay. In contrast, the non-selective adenosine receptor antagonist, 8-phenyltheophylline, failed to affect the dysmotility. Thus, adenosine A1 receptor antagonists have potent therapeutic potential against ischemia-reperfusion-induced dysmotility in the colon.

Animals↗

PubMed2000

New method for evaluating intestinal contractions in guinea pig by curve fitting.

Using a "hybrid logistic function," we attempted to develop a new approach for a quantitative and comprehensive evaluation of the force-time curve of guinea pig gut contractions. We recorded ileum twitch and proximal colon spontaneous isometric longitudinal contractions because of their high regularities. We digitized the force-time curves of both contractions and performed curve fitting to them by hybrid logistic functions with a personal computer. We found that the fitness of these functions to both contractions was excellent. The respective best-fit parameters of these functions were closely correlated with the observed mechanical indexes, all of which are physiologically meaningful. This result suggests the possibility that these parameters can characterize the magnitudes and time courses of F(t) curves of the intestinal contractions. Furthermore, it might be able to show an effect of a pharmacological agent specifically either on the contraction phase, the relaxation phase, or other parameters of each. Therefore, we insisted that the present new approach for evaluating gut motility is promising for clinical application.

Animals↗

PubMed2000

Molecular identification and pharmacological characterization of adenosine receptors in the guinea-pig colon.

The aim of this study is to elucidate the role of adenosine in the motor function of the guinea-pig distal colon.2 To determine whether adenosine A(1) receptors and A(2B) receptors are expressed in the guinea-pig colon, we employed the reverse transcription-polymerase chain reaction (RT - PCR). The gene expression of A(1) receptor and A(2B) receptor was found for the first time in the guinea-pig proximal and distal colon.3 Adenosine A(1) agonist N(6)-cyclopentyladenosine (CPA), and A(1)/A(2) agonist 5'-N-ethylcarboxamidoadenosine (NECA) concentration-dependently inhibited neurogenic responses to electrical field stimulation (EC(50)=1.07x10(-8) and 2.12x10(-8) M) in the longitudinal muscle, but A(2A) agonist 2-p-(2-carboxyethyl)phenylethylamino-5'-N-ethycarboxamido-ad enosine (CGS21680) had only a slight inhibitory effect (25.9%, 1 microM). A(1) antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 10 nM: A(1) selective concentration) antagonized responses to CPA and NECA. Furthermore, the affinity order of antagonists at inhibiting the effect NECA was: DPCPX>8-phenyltheophylline (8-PT: A(1)/A(2) antagonist).3 In the presence of tetrodotoxin (TTX, 0.3 microM), CPA and NECA relaxed myogenic precontraction induced by KCl (50 mM) (EC(50)=1.26x10(-5) and 1.04x10(-5) M, respectively), but CGS21680 (1 microM) did not cause any relaxation. DPCPX did not affect responses to CPA and NECA at a concentration of 10 nM, but a higher concentration (1 microM) of DPCPX and 10 microM of 8-PT antagonized those responses.5 These data lead us to the hypothesis that adenosine may mediate relaxation through two different inhibitory receptor subtypes; A(1) receptors on the enteric neuron and A(2B) receptor on the smooth muscle in the guinea-pig distal colon.

Acetylcholine↗

PubMed2000

Effects of gender difference and birth order on perceived parenting styles, measured by the EMBU scale, in Japanese two-sibling subjects.

The relationship between Egna Minnen av Barndoms Uppforstran (EMBU) scaling and gender, birth order and parents' gender was previously investigated in a large volunteer sample; significant interactions among the variables were found. In the present study, 730 Japanese volunteers with one sibling were used as subjects in order to control the number of siblings: the effect of gender of subjects and siblings and birth order on the perceived parenting style was examined. Based on gender and birth orders, 730 subjects were grouped into the following categories: (i) male with a younger brother; (ii) male with a younger sister; (iii) male with an older brother; (iv) male with an older sister; (v) female with a younger brother; (vi) female with a younger sister; (vii) female with an older brother; and (viii) female with an older sister. One-way ANOVA was performed with each EMBU subscale used as a dependent variable and these eight groups as independent variables. The scores for rejection and emotional warmth of father were influenced significantly by the pattern of siblings (P<0.006 and P<0.0012, respectively), and scores for emotional warmth of mother were influenced significantly by the pattern of siblings (P<0.0012). The elder male children strongly experienced parenting style as more rejecting than others, and female children (elder sisters with brother, or younger sisters with sister) recognized parenting style as more caring and demonstrated more warmth than others. The results confirmed a significant interaction of gender of subjects and siblings and birth order of perceived parental rearing behavior.

Adolescent↗

PubMed2000

Postoperative adhesion prevention with an oxidized regenerated cellulose adhesion barrier in infertile women.

OBJECTIVE: To evaluate the efficacy of an oxidized regenerated cellulose adhesion barrier as an adjuvant in preventing postoperative adhesions in infertile women undergoing reconstructive surgery. STUDY DESIGN: Thirty-eight cases of reconstructive surgery that could be followed up for more than two years (myomectomy 19, cystectomy 5, tuboplasty 10, uteroplasty 4) at the Fujita Health University Hospital were evaluated retrospectively. The barrier (Intercede, Johnson & Johnson) was used to cover the surgical site in 23 of these cases (Intercede group); no adjuvant was used in 15 cases, which represent the surgical control group (Intercede - group), including 23 second-look operation cases (16 in the Intercede and 7 in the control group). Postoperative adhesion prevention and pregnancy rates were estimated. RESULTS: At the second-look operation, six cases (37.5%) in the Intercede + group and six (85.7%) in the Intercede - group had postoperative adhesions. No significant difference was found in either intensity or area covered with adhesions between the two groups. Eighteen cases (78.3%) in the Intercede and seven (46.7%) in the Intercede - group conceived during the follow-up period. CONCLUSION: The use of Intercede significantly reduced the rate of postoperative adhesion formation, with a statistically significant increase in the pregnancy rate as compared to the surgical controls.

Cellulose, Oxidized↗

PubMed1999

Morphological relationship between serotonergic neurons and nitrergic neurons for electrolytes secretion in the submucous plexus of the guinea pig distal colon.

In the submucous plexus, double immunocytochemistry revealed that nitric oxide synthase (NOS)-immunoreactivity was found in both numerous nerve fibers and some nerve cell bodies, while 5-hydroxytryptamine (5-HT)-immunoreactivity was limited to many nerve fibers, but not any nerve cell bodies. About 30% of the total NOS positive neurons (978) had close or some contact with 5-HT positive nerve fiber, suggesting that NO may participate in the 5-HT-evoked chloride secretion.

Animals↗

PubMed1999

Autolysosomal membrane-associated betaine homocysteine methyltransferase. Limited degradation fragment of a sequestered cytosolic enzyme monitoring autophagy.

We compared the membrane proteins of autolysosomes isolated from leupeptin-administered rat liver with those of lysosomes. In addition to many polypeptides common to the two membranes, the autolysosomal membranes were found to be more enriched in endoplasmic reticulum lumenal proteins (protein-disulfide isomerase, calreticulin, ER60, BiP) and endosome/Golgi markers (cation-independent mannose 6-phosphate receptor, transferrin receptor, Golgi 58-kDa protein) than lysosomal membranes. The autolysosomal membrane proteins include three polypeptides (44, 35, and 32 kDa) whose amino-terminal sequences have not yet been reported. Combining immunoblotting and reverse transcriptase-polymerase chain reaction analyses, we identified the 44-kDa peptide as the intact subunit of betaine homocysteine methyltransferase and the 35- and 32-kDa peptides as two proteolytic fragments. Pronase digestion of autolysosomes revealed that the 44-kDa and 32-kDa peptides are present in the lumen, whereas the 35-kDa peptide is not. In primary hepatocyte cultures, the starvation-induced accumulation of the 32-kDa peptide occurs in the presence of E64d, showing that the 32-kDa peptide is formed from the sequestered 44-kDa peptide during autophagy. The accumulation is induced by rapamycin but completely inhibited by wortmannin, 3-methyladenine, and bafilomycin. Thus, detection of the 32-kDa peptide by immunoblotting can be used as a streamlined assay for monitoring autophagy.

Animals↗

PubMed1999

Involvement of 5-HT3 and 5-HT4 receptors in the motor activity of isolated vascularly perfused rat duodenum.

The involvement of serotonin (5-HT) receptor subtypes in motor activity of the ex vivo vascularly perfused rat duodenum was investigated. Clusters of phasic contractions (CPCs), migrating in an oral to anal direction, were obtained without any stimulation. Drug effects were evaluated by changes in different components of the pressure waves, such as motor index (MI), frequency, amplitude and duration of the CPC. The effect of 5-HT depletion on motor activity was examined in animals treated with p-chlorophenylalanine (PCPA). The MI, frequency and duration of CPC were decreased by PCPA, but the amplitude was not affected, suggesting that endogenous 5-HT may play an important role in regulation of the motor activity of the rat intestine. The importance of the 5-HT receptor subtypes in the regulation of motor activity was examined. Neither the nonselective 5-HT1 and 5-HT2 receptor antagonist, methysergide, nor the 5-HT2 receptor antagonist, ketanserin, affected motor activity. However, the 5-HT3 receptor antagonists, granisetron and azasetron, decreased percentage MI, frequency, percentage amplitude and percentage duration of CPC. The 5-HT4 receptor antagonist, SB204070, exerted both excitatory and inhibitory actions, with a higher dose (10 nM) stimulating percentage MI, frequency, percentage amplitude and percentage duration, and a lower dose (0.1 nM or 1 nM) decreasing percentage MI and percentage duration of CPC. These results suggest that endogenous 5-HT regulates the motor activity of the rat duodenum through 5-HT3 and 5-HT4 receptors, with the former mediating the stimulatory influence and the latter mediating both stimulatory and inhibitory influences.

Animals↗

PubMed1999

Factor analysis of the EMBU scale in a large sample of Japanese volunteers.

OBJECTIVE: The EMBU (Egna Minnen av Barndoms Uppfostran; (one's memories of upbringing') is a convenient and reliable instrument for the assessment of parental attitudes. The aim of the present study was to investigate the extent to which the factor structure of the EMBU, obtained in previous investigations, could be retrieved in a large Japanese sample. METHOD: The EMBU scale was administered to 1320 healthy Japanese volunteers. Both exploratory and confirmatory factor analyses were performed. RESULTS: The first factor in the analysis, accounting for 9.9% (father) and 10.6% (mother) of the variance, consisted of rejection items. The second factor, accounting for 9.1% (father) and 8.6% (mother) of the variance, contained items relating to emotional warmth. The third factor appeared to represent overprotection, and accounted for 7.8% (father) and 7.8% (mother) of the variance. The fourth factor, which accounted for 3.7% (father) and 3.7% (mother) of the variance, included items classified under favouring subjects. Confirmatory factor analysis revealed that this four-factor structure fitted our data very well for both the father and the mother. The results of factor analysis for four subscales showed three major factors for the EMBU. CONCLUSION: The results of this study confirmed that the EMBU yielded a factor structure in Japan similar to that found in European countries. The EMBU is useful for comparison of parenting attitudes in different societies or countries.

Adult↗

PubMed1999

Characteristics of perceived parenting styles in Japan using the EMBU scale.

OBJECTIVE: The EMBU (Egna Minnen av Barndoms Uppfostran) is a self-report questionnaire for the assessment of one's memory of parental rearing experiences. We are interested in using this scale to determine the characteristics of perceived parenting styles in Japan. METHOD: The study subjects consisted of 1320 healthy Japanese volunteers, comprising 687 males (52%) and 633 females (48%). We investigated the relationship between demographics and the EMBU scale. RESULTS: ANCOVA revealed that the subject's gender had a significant effect on paternal rejection scores (male > female), and both gender and birth-order position had significant effects on emotional warmth scores for both parents (female > male, and only-child > middle or last-born child). Birth-order position had significant effects on maternal over-protection, with the highest score being that of only children, and on the aspect of favouritism (favouring subjects), scores for both parents were highest from the last-born children. Rejection scores for the mother were significantly higher than those for the father from female subjects. Among both male and female subjects, emotional warmth scores and overprotection scores for the mother were significantly higher than those for the father. Among male subjects, scores for the mother on favouritism of the subject were significantly higher than those for the father. On the other hand, among female subjects, scores for the father on favouritism of the subject were higher than scores for the mother. CONCLUSION: Our results suggest that parenting styles have significant interrelationships with the gender and birth-order position of the subject.

Adult↗

PubMed1998

Identification of autolysosomes directly associated with proteolysis on the density gradients in isolated rat hepatocytes.

Autophagy-related vacuoles, i.e., autophagosomes (AVi), autolysosomes (AVd) and dense bodies (DB), are intracellular organelles within which macroautophagy and bulk proteolysis set out and progress. Separation of these particles in freshly isolated rat hepatocytes, monitored by beta-hexosaminidase, a lysosomal marker enzyme, was established by density gradient centrifugation. Percoll density gradients were modified and improved by adding free polyvinylpyrrolidone (PVP, 0.75%) to 60% Percoll, which made it possible to separate AVd (buoyant peak, d = 1.090) and DB (dense peak, d = 1.131) effectively. Addition of graded levels of a regulatory amino acid mixture (Reg AA) to hepatocyte incubation not only suppressed proteolysis, but also lead to a shift of vacuolar profiles on the density gradients from the buoyant to the dense region. Alterations in the vacuolar shift and proteolysis were highly proportional over a full range of regulation by Reg AA. Morphometric analysis of autophagic vacuoles by electron microscopy revealed changes in the aggregate volumes of both AVi and AVd by Reg AA, which enabled us to estimate autophagic subpopulation of the buoyant peak on the gradient profile. All the results demonstrate that AVd shifts on the density gradients in proportion to alterations in proteolysis regulated by amino acids, and thus the gradient profile can be used as a measure of macroautophagy; and in addition that AVd actively involved in proteolysis occupies only a part of the buoyant peak on the gradients.

Amino Acids↗