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Biomedical subjects

N Toyoda

Publications and source records attributed to N Toyoda.

At least 37 records · Page 2Linked to original sources
PubMed2000

Expression of glucose transporter 4 mRNA in adipose tissue and skeletal muscle of ovariectomized rats treated with sex steroid hormones.

The effects of 17beta-estradiol (E) and/or progesterone (P) on glucose transporter 4 (GLUT4) expression in the adipose tissue and skeletal muscle of ovariectomized female rats were studied. The Sprague-Dawley rats received daily subcutaneous injections of various doses of E and/or P for 7 days (n=5-6 per dose). The expression of GLUT4 mRNA was assessed by performing ribonuclease protection assays. GLUT4 protein levels were assessed by Western blotting assays. The adipose tissue levels of GLUT4 mRNA were reduced by the administration of 50 microg E, which resulted in unphysiologically high serum E concentrations. Although the GLUT4 mRNA levels did not change after the administration of 10 microg E or 5 mg P, they were reduced significantly to approximately half the control group level by the administration of both hormones (p <0.01). The skeletal muscle GLUT4 mRNA levels were not changed significantly by hormone treatment. These findings suggest that E and P may be involved in the regulation of GLUT4 mRNA expression in adipose tissue.

Adipose Tissue↗
PubMed2000

Relation of rat fetal body weight to the relative expression of insulin genes I and II.

This study investigates the relation between the ratio of the abundance of mRNAs encoded by insulin genes I and II (insulin I/II mRNA ratio) and the weight of rat fetuses on gestational day 20. Total RNA was extracted from the pancreas of the fetuses with the maximum and minimum body weight in each litter on gestational day 20. The amount of insulin mRNAs I and II in each RNA preparation was determined by reverse transcription-polymerase chain reaction (RT-PCR) analysis and restriction enzyme digestion. The maximum and minimum weight of the fetuses were 4.07 +/- 0.23 and 3.23 +/- 0.34 g, respectively (N = 18, P < .01) and the corresponding insulin I/II mRNA ratios were 3.65 +/- 0.55 and 1.42 +/- 0.21 (N = 18, P < .01). Furthermore, the insulin I/II mRNA ratio correlated significantly with fetal weight (r = .526, P < .05). These results suggest that the relative expression of insulin genes I and II may affect the extent of fetal growth.

Animals↗
PubMed2000

Comparison of the validity of the criteria for gestational diabetes mellitus by WHO and by the Japan Society of Obstetrics and Gynecology by the outcomes of pregnancy.

Data for 416 Japanese pregnant women who received a 75g oral glucose tolerance test (OGTT) for determination of gestational diabetes mellitus (GDM) in 13 hospitals in Japan were analyzed retrospectively. Comparison of the diagnostic criteria of the World Health Organization (WHO) and the Japan Society of Obstetrics and Gynecology (JSOG) revealed pregnant women who met the latter criteria for GDM to have significantly higher incidences of low Apgar scores, respiratory problems, neonatal hypoglycemia, preterm delivery and requirements for insulin therapy and cesarean section. The women who met the WHO criteria but not the JSOG criteria had minor complications. These observations suggest that the GDM criteria of the JSOG are more appropriate than the WHO criteria from the standpoint of therapeutic intervention for pregnant women.

Adult↗
PubMed2000

Second generation amplicor-HCV monitor assay: clinical features and predictors of the response to interferon.

The aims of this study were to compare the amplicor-HCV monitor assay versions 1.0 and 2.0, and to investigate the clinical usefulness of this assay in patients with chronic hepatitis C. We retrospectively analyzed 154 patients, and 133 of these patients received interferon therapy. Sixty-nine patients were complete responders (CR), and 64 were non-responders. Serum HCV RNA levels of version 1.0 and version 2.0 and HCV genotypes were determined in all patients. There was a good correlation between versions 1.0 and 2.0 in both genotype 1b and 2a, 2b (r=0.907 and 0.726, respectively). In genotype 1b, the mean HCV RNA level obtained by version 1.0 was 384+/-547 kcopies/ml and that obtained by version 2.0 was 488+/-825 kI.U./ml. In genotype 2a/2b, the mean level obtained by version 1.0 was 170+/-369 kcopies/ml and that obtained by version 2.0 was 340+/-402 kI.U./ml. Discriminant analysis revealed that the discriminating points of IFN response were 168 kcopies/ml (genotype 1b, version 1.0), 106 kcopies/ml (genotype 2a and 2b, version 1.0), 102 kI.U./ml (genotype 1b, version 2.0), and 277 kI.U./ml (genotype 2a and 2b, version 2.0). When the patients were stratified according to the discriminating points, the CR rate below the discriminating points were 73.8 and 86.2% in versions 1.0 and 2.0, respectively, in genotype 1b, and the rates were 73.2 and 82.3% in genotype 2a/2b. In addition, receiver-operating characteristic analysis revealed that version 2.0 had significantly better discriminative ability in patients with genotype 1b. We conclude that the second version of the amplicor-HCV monitor assay measures HCV RNA levels with the same precision as version 1.0 and is more useful for the prediction of interferon response than version 1.0.

Journal Article↗
PubMed2000

In vitro fertilization and intracytoplasmic sperm injection for couples with unexplained infertility after failed direct intraperitoneal insemination.

PURPOSE: The objective was to determine the optimal insemination technique in patients undergoing in vitro fertilization (IVF) after failed direct intraperitoneal insemination (DIPI) and the outcome of intracytoplasmic sperm injection (ICSI) in such cases. METHODS: In case-control studies, 53 couples with unexplained infertility who underwent IVF after four failed DIPI cycles were compared with 75 couples with tubal or endometriosis infertility as controls. Thirty couples with unexplained infertility after failing to conceive with DIPI and conventional IVF who underwent ICSI and 58 couples with male-factor infertility as controls also were compared. Fertilization cleavage, embryo quality, implantation, and pregnancy were compared after IVF and after ICSI. RESULTS: There was a significant difference in fertilization rates after IVF between cases of unexplained infertility after failing to conceive with DIPI (40.4%) and patients with tubal or endometriosis infertility (67.9%). There also was a significant difference in total fertilization failure rates between the two groups (30.4% and 3.9%, respectively). There was a slight but significant difference in numbers of fertilized oocytes after ICSI between patients with low fertilization rate undergoing IVF after failing to conceive DIPI (85.8%) and patients with male factor (90.4%). Total fertilization failure was not observed in these cases. CONCLUSIONS: Couples with unexplained infertility after failing to conceive with DIPI show a failed fertilization or a low fertilization rate after IVF. However, they demonstrated a good chance of becoming pregnant after subsequent ICSI, even with statistically significant difference in fertilization rate as compared with male-factor cases.

Adult↗
PubMed2000

Expression of tenascin-C in stromal cells of the murine uterus during early pregnancy: induction by interleukin-1 alpha, prostaglandin E(2), and prostaglandin F(2 alpha).

Tenascin-C (TN-C), an extracellular matrix glycoprotein, is known to be expressed in uterine stroma in the peri-implantation period. Examination of the spatiotemporal pattern during early pregnancy using immunohistochemistry and in situ hybridization revealed TN-C expression in the stroma beneath the luminal epithelia of the murine endometrium on Days 0 and 1 of pregnancy, subsequent disappearance, and reappearance on Day 4. After decidualization, tissue around the deciduoma was positive. In situ hybridization demonstrated TN-C production by the stromal cells adjacent to the epithelia. To investigate the regulation of TN-C expression in vitro, murine uterine stromal and epithelial cells were isolated and cultured. Addition of interleukin-1 alpha (IL-1 alpha) and prostaglandin E(2) (PGE(2)) and F(2 alpha) (PGF(2 alpha)) induced TN-C expression in the stromal cells at both protein and mRNA levels, while the sex steroid hormones, progesterone and ss-estradiol, exerted little effect. Immunohistochemistry using anti-IL-1 alpha antibody showed epithelial cells to be positive on Days 2-4 of pregnancy, and addition of progesterone but not ss-estradiol enhanced IL-1 alpha expression in epithelial cells in vitro. In a culture insert system, TN-C expression by stromal cells cocultured with epithelial cells was induced by addition of progesterone alone that was blocked by additions of anti-IL-1 alpha antibody. Collectively, these findings indicate that TN-C expression in the preimplantation period is under the control of progesterone, but not directly, possibly by the paracrine and autocrine intervention of IL-1 alpha secreted by epithelial cells and PGE(2) and PGF(2 alpha) secreted by stromal cells.

Animals↗
PubMed2000

Changes of hemostatic molecular markers after gynecological surgery.

The authors evaluated the hemostatic abnormalities occurring in the postoperative period of eight patients with malignant tumors and compared them with those occurring in the postoperative period of eight patients with benign tumors. Two of the patients with malignant tumor presented pulmonary embolism after operation. Plasma fibrinogen and fibrin degradation product levels in patients with malignant tumors were already high before operation and further increased significantly after operation. The plasma levels of D-dimer, thrombin-antithrombin complex, and free-tissue factor pathway inhibitor were increased in both groups after operation, but they were higher in patients with malignant tumors than in patients with benign tumors. The plasma levels of protein C and antithrombin were significantly decreased in both groups after operation. but they were significantly lower in patients with malignant tumors than in those with benign tumors. The decreased activity of protein C or antithrombin may be not only a risk factor of thrombotic disease, such as pulmonary embolism, but also the cause of thrombosis. In patients with malignant tumors, the operation time was significantly longer than that in patients with benign tumors. This long operative period might cause vascular endothelial cell injury which is reflected by the plasma levels of free-tissue factor pathway inhibitor, antithrombin, and protein C.

Adult↗
PubMed2000

A case of obesity, diabetes and hypertension treated with very low calorie diet (VLCD) followed by successful pregnancy with intrauterine insemination (IUI).

The patient was a 32-year-old obese woman with a history of type 2 diabetes and hypertension for 6 years. Although she was treated with antihypertensive agents and intensive insulin therapy, her hyperglycemia was difficult to control. She wanted to have a baby but pregnancy was not recommended because her diabetes was under poor control and the use of antihypertensive medication. To achieve good control of obesity, diabetes and hypertension, she was admitted to our clinical department for weight reduction using very low calorie diet (VLCD). During VLCD she had a 19.8 kg reduction in body weight and her blood glucose and blood pressure were in good control without the use of drugs. Five months later, she became pregnant after the fourth trial of intrauterine insemination (IUI) and gave birth to a female baby under insulin therapy. This is the first report that showed the usefulness of VLCD for prepregnant control of glucose metabolism and blood pressure in an obese hypertensive patient with type 2 diabetes mellitus.

Adult↗
PubMed2000

Immunologic evaluation of an Escherichia coli O157-infected pregnant woman. A case report.

BACKGROUND: To the best of our knowledge, this is the first case of pregnancy complicated by hemorrhagic enterocolitis due to Escherichia coli O157. CASE: A woman with hemorrhagic enterocolitis due to E coli O157 was seen at 32 weeks of gestation. We investigated her immune response to 0157 lipopolysaccharide and to Shiga toxin in the sera and breast milk. CONCLUSION: IgM and IgA to 0157 lipopolysaccharide in the breast milk of this patient might protect her infant after the disappearance of serum IgM.

Adult↗
PubMed1999

Age- and sex-related changes in type-1 iodothyronine deiodinase messenger ribonucleic acid in rat liver and kidney.

To evaluate the age- and sex-related changes in Type 1 iodothyronine deiodinase gene expression in the liver and kidneys, we measured 5'-deiodinating activity and deiodinase mRNA in developing rats. The activity in the liver increased after birth, and that in neonates was approximately half that in adults. In contrast, the activity in neonatal kidneys remained very low. The relative importance of activity in male kidneys compared to the liver increased from the ages of 1 to 20 days. The male adult rat liver showed a higher level of activity than the female liver. Deiodinase mRNA in the male liver gradually increased from 1 to 20 days, in correlation with the activity. In kidneys, deiodinase mRNA was low before day 20, and there was no significant sex difference in all age groups. In orchiectomized male rats, the activity and mRNA in the liver was similar to the low levels found in females; however, the levels in the kidneys were not significantly different than those of normal males. These data suggest that the age- and sex-related changes in iodothyronine deiodinase gene expression are regulated mainly at the pretranslational level, and that the relative importance of kidneys to liver in iodothyronine deiodinase increases from birth to age 20 days due to the difference in the gene expression.

Aging↗
PubMed1999

Expression of GLUT4 glucose transporter protein in adipose tissue and skeletal muscle from streptozotocin-induced diabetic pregnant rats.

Depletion of GLUT4, the primary glucose transporter protein in adipose tissue and skeletal muscle, is reported to contribute to insulin resistance in pregnancy or diabetes. To examine this phenomenon, the expression of GLUT4 protein was assessed by Western blotting in streptozotocin-induced diabetic pregnant rats. In adipose tissue, relative to control, it was decreased by 30% in the normal pregnant group (p<0.001), by 37% in the diabetic nonpregnant group (p<0.01) and by 65% in the diabetic pregnant group (p<0.001). On the other hand, no significant variation was evident among the groups in skeletal muscle. To assess the mechanisms responsible for depletion of GLUT4 protein in adipose tissue, we quantitated levels of GLUT4 mRNA with a RNase protection assay. It was decreased by 44% in the normal pregnant group (p<0.05) and by 55% in the diabetic pregnant group (p<0.05), but not altered in the diabetic nonpregnant group. These results suggest that the depletion of GLUT4 protein in adipose tissue is a factor contributing to insulin resistance in pregnancy or diabetes, especially when the two states exist in combination.

Adipose Tissue↗
PubMed1999

Glucose transporter 4 (GLUT4) mRNA abundance in the adipose tissue and skeletal-muscle tissue of ovariectomized rats treated with 17 beta-estradiol or progesterone.

OBJECTIVE: To investigate the effects of 17 beta-estradiol and progesterone on the expression of glucose transporter 4 (GLUT4) in the adipose tissue and skeletal-muscle tissue of ovariectomized rats. METHODS: Female Sprague-Dawley rats (n = 63) received a daily subcutaneous injection of 10 micrograms, 50 micrograms, or 250 micrograms of 17 beta-estradiol (Group E) or of 1 mg, 5 mg or 25 mg of progesterone (Group P) for 3 days, 7 days, or 10 days (n = 3, at each dose). The expression of GLUT4 mRNA was assessed by performing ribonuclease protection assays. RESULTS: The levels of GLUT4 mRNA in adipose tissue was significantly reduced by treatment with estradiol, 50 micrograms or 250 micrograms, relative to findings in control rats (p < 0.01). No such reductions were seen regarding the progesterone treatment. The level of GLUT4 mRNA in skeletal-muscle tissue did not change, regardless of treatment. CONCLUSION: In ovariectomized rats, higher than physiologic dosages of 17 beta-estradiol can suppress the expression of GLUT4 mRNA in adipose tissue.

Adipose Tissue↗
PubMed1999

A case report: rare case of primary transitional cell carcinoma of the fallopian tube.

Carcinomas other than adenocarcinomas are extremely rare in the fallopian tube. A 42-year-old woman with watery, intermittent vaginal discharge was found to have a left adnexal tumor. This case was diagnosed as primary carcinoma of the fallopian tube, FIGO Stage Ia. She underwent a total abdominal hysterectomy, a bilateral salpingo-oophorectomy, a pelvic and periaortic lymphoadenectomy, and an omentectomy, followed by cisplatin-based chemotherapy. Four years after the initial diagnosis of the disease, she remains in a disease-free state. Histologically, the tumor revealed a primary transitional cell carcinoma of the left fallopian tube. The findings on an immunohistochemical test for an epithelial membrane antigen, the CA125 antigen, were positive, whereas findings on a test for CEA were negative. We report a case of a malignant neoplasm of the fallopian tube with histological features of transitional cell carcinoma that arose from the tubal epithelium.

Adult↗
PubMed1999

[Detection of bactericidal antibody in the breast milk of a mother infected with enterohemorrhagic Escherichia coli O157:H7].

A 21 years-old pregnant woman developed diarrhea, fresh bloody stools and abdominal pain on April 6th 1997 at 32 weeks of gestation, and was admitted to the hospital on April 11th. The stool culture on admission was positive for enterohemorrhagic Escherichia coli (EHEC) O157:H7 (Stx1 and 2). Clinical laboratory data during admission showed only slight elevation of beta-microglobulin and N-acetyl glucosaminidase in the urine, and no neurological or hemolytic symptoms were seen. After the antibiotic and lactobacillus administration, all her symptoms were relieved and no abnormal findings in pregnancy were observed. She delivered a baby girl normally on May 30th. Serum (between 41 and 120 days from the onset) and milk (between 4 and 64 days post partum) samples from the mother, and serum (64 days of age) from a baby and cord blood were obtained to monitor the immune status against EHEC O157:H7 and against Shiga toxins (Stx). Anti-E. coli O157 LPS antibodies (IgA, G and M) were assayed by the ELISA method. Neutralizing anti-Stx antibodies were measured by using ACHN cell cytotoxicity assay. In the colostrum and mature milk, high levels of IgA and IgM, and no IgG antibodies against EHEC O157 LPS were detected. In one of the control colostrum samples obtained from 4 healthy mothers IgA antibody against EHEC O157 LPS was detected. To assess the potency of protection against EHEC O157:H7 by the breast milk, we monitored it by the bactericidal activity for the organism under complement-coincubation experiment, and by the neutralization test for the Stx cytotoxicity. As a result, breast milk samples (both colostrum and mature milk) from a patient were demonstrated to kill the organisms. One of 4 healthy milk samples, showed bactericidal activity though it was negative in O157-LPS antibody. This bactericidal activity seen in one healthy colostrum is possibly due to a nonspecific reaction caused by non-O157 E. coli infection. From these observations, it was suggested that the bactericidal activity was due to the IgM class antibody against EHEC O157:H7. However, the neutralizing antibody against Stx1 and 2 could not be detected in any sample. EHEC infection at late gestation did not cause adverse effects to a fetus, and breastfeeding may have advantage for the protection of a baby against EHEC infection.

Adult↗
PubMed1999

Effect of nicotine on type 2 deiodinase activity in cultured rat glial cells.

Intracellular generation of triiodothyronine (T3) from thyroxine (T4) by type 2 deiodinase (D2) in the mammalian brain, plays a key role in thyroid hormone action. The presence of D2 in rat astrocytes suggests the importance of glial cells in the regulation of intracellular T3 levels in the rat central nervous system (CNS). To analyze further the factors that regulate D2 activity in the CNS, we investigated the effects of nicotine and of mecamylamine, which inhibits the binding of nicotine with nicotinic acetylcholine receptors, on D2 activity in cultured mixed glial cells of the rat brain. We incubated cultured mixed glial cells obtained from neonatal Wistar rats in the presence of 10 mM dithiothreitol, 2 nM [125I] reverse T3 and 1 mM 6-N-propyl-2-thiouracil for 2 h at 37 degrees C, and the released 125I- was counted in a gamma counter. D2 activity of cultured cells was dependent on the temperature and the amount of protein. The basal D2 activity of rat mixed glial cells was 1.9 +/- 0.2 fmol of I- released/mg protein/h (mean +/- SEM). The addition of 10(-11), 2 x 10(-11), 10(-10), and 10(-9) M nicotine significantly increased D2 activity to approximately 2.2-, 2.4, 3.5- and 2.9-fold the basal level, respectively. D2 activity stimulated by 10(-8) M nicotine (2.5-fold) reached a peak after 9 h incubation. The stimulatory effect of nicotine was completely blocked by 10(-6) M mecamylamine. In conclusion, nicotine increases D2 activity probably via nicotinic acetylcholine receptors, and may influence brain function, at least in part, by affecting thyroid hormone metabolism.

Animals↗
PubMed1999

Effect of triiodothyronine administration on reduced expression of type 1 iodothyronine deiodinase messenger ribonucleic acid in streptozotocin-induced diabetic rats.

To examine the mechanism behind a decrease in type 1 iodothyronine deiodinase (D1) gene expression in diabetes mellitus, we evaluated the effect of administering T3 and/or insulin on D1 activity and the mRNA levels in the liver of streptozotocin (STZ)-induced diabetic rats. STZ (100 mg/kg BW) was administered to male Wistar rats, and the rats were divided into four groups as follows: (1) STZ alone, (2) STZ and T3 (5 microg/100 g BW daily for 7 days), (3) STZ and insulin (intermediate-acting insulin, 4 units/100 g BW daily for 7 days), and (4) STZ, T3, and insulin. Blood glucose levels increased in Group 1, but were normalized in Group 3. Serum T3 levels were markedly decreased in Group 1. They were within normal limits 24 hours after the last administration of T3 in Group 2 and after the administration of insulin in Group 3. T3 levels were supranormal in Group 4. TSH levels were normal in Groups 1 and 3, but were suppressed in Groups 2 and 4, suggesting that rats in Groups 2 and 4 were actually in a hyperthyroid state after injecting a large amount of T3. D1 activity in Group 1 was reduced significantly, but it was normal in Groups 2 and 3, and increased in Group 4. D1 mRNA levels in the liver in Group 1 decreased significantly, but they were increased to within normal limits by adding insulin in Group 3. They were also normal in Group 2 where hyperglycemia was evident and rats were hyperthyroid after administering T3. D1 mRNA in Group 4 increased significantly where glucose levels were normal and T3 levels were increased. We suggest that the decrease in hepatic D1 mRNA in STZ-induced diabetic rats is due to metabolic derangement caused by insulin deficiency in addition to a possible decrease in tissue T3 availability.

Animals↗
PubMed1999

Effect of streptozotocin-induced diabetes mellitus on type 1 deiodinase (D1) in inherited D1-deficient mice.

We investigated the effects of streptozotocin (STZ)-induced diabetes on thyroid hormone levels, type 1 deiodinase (D1) activity and messenger RNA (mRNA) levels in inherited D1 deficient C3H mice in a comparative manner with control C57 mice. The apparent maximum velocity (Vmax) D1 values in C3H mice were 3% (liver) and 26% (kidney) of those in C57 mice. In C3H mice, similar serum T3, slightly higher T4, and 2.6-fold higher rT3 levels were observed compared with C57 mice. In STZ-induced diabetes, serum T4 level markedly decreased in both C3H and C57 mice. Serum T3 levels in STZ-C3H mice similarly decreased as in STZ-C57 mice. On the other hand, serum rT3 levels increased to 3.3-fold higher in STZ-C3H than in STZ-C57 mice. The Vmax values were decreased to 12% (STZ-C3H) and to 30% (STZ-C57) in liver, and decreased to 33% (both STZ-C3H and STZ-C57) in kidney. The changes in D1 mRNA levels in diabetes versus control were comparable to those of D1 activities in both strains. In summary, similar mechanism(s) to those which decrease the D1 expression and the serum T3 level in diabetes, function in D1 deficient C3H mice as in C57 mice. It appears that hepatic and renal D1 activity alone can not explain the similar reduction in T3 level in STZ-C3H mice and STZ-C57 mice.

Animals↗