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Biomedical subjects

M Fukushi

Publications and source records attributed to M Fukushi.

At least 19 recordsLinked to original sources
PubMed2001

Effects of dioxins and polychlorinated biphenyls (PCBs) on thyroid function in infants born in Japan--the second report from research on environmental health.

Dioxins (PCDD + PCDF) and polychlorinated biphenyl (PCB) are potentially hazardous compounds and have structural similarity to thyroid hormones. Our research group on "Dioxins and PCB in Human Milk" was organized in 1997 and has been active for the past three years. We collected breast milk from 80 mothers living in Tokyo, Saitama, Ishikawa and Osaka Prefecture in Japan at 5, 30, 150, 300 postpartum days and measured PCDDs, PCDFs and PCBs during 1998-1999. We added another 20 prefectures and cities during 1999-2000. Breast milk was obtained from 415 mothers at 30 postpartum days (breast-feeding group). Blood was taken from infants who were breast-fed at the age of 1 year for evaluation of thyroid and immune functions. Blood was also taken from 53 infants who were bottle-fed (bottle-feeding group) as a control. Serum T4, T3, FT4 and TSH levels in the breast-feeding (n = 337) and bottle-feeding (n = 53) groups were within normal ranges and were not significantly different between the two groups. Although there were a large geographic differences of dioxins and co-PCB content in breast milk, there were no differences in serum T4, T3, FT4, TSH levels and no significant correlation between the mean serum levels of TSH and TEQ in breast milk. There was a significant correlation between serum TSH at 1 year of age and that from blood on dried filter paper TSH at 5 days of age. We concluded that dioxin intake from breast milk in Japanese infants did not impair thyroid function. However, long-term effects remain to be evaluated.

Adult↗
PubMed2001

Interleukin-2-dependent but not independent T-cell lines infected with human T-cell leukemia virus type 1 selectively express CD45RO, a marker for persistent infection in vivo.

Human T-cell leukemia virus type 1 (HTLV-1) is an etiologic agent of adult T-cell leukemia. HTLV-1 is exclusively detected in CD45RO+ T-cells in infected individuals, but CD45RO is weakly expressed in HTLV-1-transformed T-cell lines in vitro. The aim of this study was to investigate the role of CD45RO in the persistent HTLV-1 infection in vivo. Flow cytometry showed that only two out of eight interleukin(IL)-2-independent HTLV-1-transformed T-cell lines expressed CD45RO, whereas all five IL-2-dependent ones expressed CD45RO, and the level of expression was higher in IL-2-dependent than in IL-2-independent cells. The high CD45RO expression in IL-2-dependent cell lines was not due to IL-2, since IL-2 had little effect on the expression of CD45RO in T-cell lines. Using western blotting, we showed that IL-2-dependent HTLV-1-transformed T-cell lines expressed a lower level of expression of the viral transcriptional regulatory protein Tax than IL-2-independent ones, and that the level of expression correlated inversely with that of CD45RO. However, the expression of Tax in one HTLV-1-negative T-cell line little affected the expression of CD45RO, suggesting that Tax at least alone does not suppress the expression of CD45RO in HTLV-1-infected T-cell lines, and that other viral or cellular factor(s) are probably involved in such suppression. Our results suggest that CD45RO+ Tax-low IL-2-dependent T-cell lines in vitro correspond to the persistent HTLV-1-infected cells in vivo, and HTLV-1-infected cells in vivo are immortalized in IL-2-dependent manner.

Cell Line↗
PubMed2000

Activation of oncogenic transcription factor AP-1 in T cells infected with human T cell leukemia virus type 1.

Human T cell leukemia virus type 1 (HTLV-1) Tax protein transforms primary human T cells in vitro. We previously showed that Tax induces the expression of various family members of the transcription factor AP-1 such as c-Jun, JunD, c-Fos, and Fra-1 at the mRNA level in T cells. In this study, we have examined the ability of Tax to activate transcription through the AP-1-binding site (AP-1 site). A transient transfection study showed that Tax can activate transcription through the AP-1-binding site in a human T cell line, whereas any combination of AP-1 proteins did so much less than Tax, indicating that the activation of the AP-1 site by Tax may require a mechanism other than the induction of AP-1 mRNA. Fresh peripheral blood leukemia cells of all surveyed ATL patients displayed constitutive AP-1 DNA-binding activity, whereas no normal individuals did. However, the HTLV-1 genes, including tax, are not significantly expressed in fresh leukemia cells from ATL patients. Our present results suggest that activation of AP-1 occurs through Tax-dependent and -independent mechanisms in HTLV-1-infected T cells, which may play some roles in dysregulated phenotypes of HTLV-1-infected cells.

Animals↗
PubMed2000

Postpartum thyroid dysfunction in women with normal thyroid function during pregnancy.

OBJECTIVE: The aim of this study was to establish the risk of postpartum thyroid dysfunction (PPTD) in women who had normal thyroid function during pregnancy and no history of thyroid disease. DESIGN: Four thousand and twenty-two consecutive pregnant women were screened for thyroid function and antithyroid antibody. Among women with normal thyroid function during pregnancy and no history of thyroid disease, thyroid function were assessed in 131 of 388 antithyroid antibody positive (Group I) and 1030 of 3503 antibody negative (Group II) women at 1 and 3 months postpartum. In Group I women who experienced PPTD, the frequency of later manifestation of Hashimoto's disease was compared according to titres of antithyroid antibodies. MEASUREMENTS: Blood samples in early pregnancy, and at 1 month and 3 months postpartum were obtained using the dried blood spot method. Levels of fT4 were measured by RIA, TSH by fluoroimmunoassay or ELISA, antimicrosome antibody (AMC) and antithyroglobulin antibody (ATG) by indirect agglutination reactions. RESULTS: The prevalence of PPTD at 1 month and 3 months postpartum were found to be 6.9% and 21.3% in Group I, and 5.3% and 4.7% in Group II, respectively. The prevalence of PPTD was significantly higher at 3 months postpartum in Group I (P<0.05). 27.3% of women with PPTD in Group I were later found to have Hashimoto's disease and 9.1% manifested hypothyroidism without goitre. A high AMC titre (> or = 25600) at 3 months postpartum in women with PPTD was related to the manifestation of Hashimoto's disease. AMC titres of PPTD women and women who developed Hashimoto's disease were significantly higher than those of control women who did not experience PPTD. CONCLUSION: A high prevalence of PPTD was found in women with antithyroid antibodies who were euthyroid during pregnancy. Prolonged follow-up of the subsequent thyroid function may be needed in women who experience PPTD and/or show a high titre of antithyroid antibody.

Autoantibodies↗
PubMed1999

Identification and cloning of a novel cellular protein Naf1, Nef-associated factor 1, that increases cell surface CD4 expression.

The nef gene of human and simian immunodeficiency virus is a key factor in acquired immunodeficiency syndrome pathogenesis and virus replication. Several Nef-induced phenomena, including the down-regulation of CD4 molecule, have been previously reported. In this study, we have identified and cloned a novel cellular protein Naf1 (Nef-associated factor 1), which associated with Nef in the yeast two-hybrid system and pull-down assay. The Naf1 gene generates two isoforms (Naf1alpha and beta) containing four coiled-coil structures. The Naf1 mRNA is ubiquitously expressed in human tissues with strong expression in peripheral blood lymphocytes and spleen. Naf1 overexpression increased cell surface CD4 expression. Nef suppressed this Naf1-induced augmentation of CD4 expression, providing a novel mode of Nef action in CD4 down-regulation.

Amino Acid Sequence↗
PubMed1999

Epitope mapping of rat neutralizing monoclonal antibody against human immunodeficiency virus type-1 by a phage peptide library: comparison with ELISA using synthetic peptides.

We generated a rat monoclonal antibody (mAb W#10) with the ability to neutralize human immunodeficiency virus type 1IIIB (HIV-1IIIB) infection. The epitope recognized by mAb W#10 was defined as R-I-Q-R-G-P-G by enzyme-linked immunosorbent assay (ELISA) with the use of synthetic peptides. The filamentous phage clones displaying random 15-amino-acid peptides on the amino terminus of the pIII coat protein reacting with mAb W#10 were identified with affinity and immunological selection procedures. Thirteen out of 16 selected phage clones contained the G-X-G-R-X-F sequence in the coat protein region representing significant homology to a part of conserved G-P-G-R-A-F sequence in the V3 loop of various HIV-1 strains. In addition, the phage clones included the G-X-G sequence in the sequence detected by synthetic peptides as the recognition site. The selected phage clones were stained by mAb W#10 specifically and were able to compete with mAb binding to cells expressing viral antigens.

Amino Acid Sequence↗
PubMed1999

Newborn screening for congenital adrenal hyperplasia in Sapporo City: sixteen years experience.

A screening program for congenital adrenal hyperplasia (CAH) in Sapporo began in 1982, 7 years prior to the introduction of the national program. Since its inception, testing has involved the detection of 17-hydroxyprogesterone (17-OHP) in dried blood samples, using ELISA. Up to the end of March 1998, of 298,731 newborn screened, second samples were requested in 1,723 cases (0.6%). This number included 789 newborns who weighed less than 2,000 gm at birth. A total of 14 cases were diagnosed with 21-hydroxylase deficiency (21-OHD). "Salt-wasting type (SW)" outnumbered "simple virilizing type (SV)" by 11:3. The ratio of male to female was a converse. but unrelated, 3:11. Our study from 1982-1997 revealed that the incidence of 21-OHD in Sapporo City was 1:21.338, markedly similar to the worldwide incidence of 1:15,000. In order to improve the program, other type of analysis are also currently in use and under evaluation. These include highly sensitive HPLC analysis for 17-OHP and molecular analysis to identify some mutations associated with the 21-OHD gene (CYP21). These methodologies are very useful for the confirmation of information acquired from dried blood specimens.

17-alpha-Hydroxyprogesterone↗
PubMed1999

International cooperation in neonatal screening: technical training course for newborn and infant screening.

We report the outline and results of our experience with a group training course of neonatal screening for health care professionals in developing countries. Sapporo City Institute of Public Health (SCIPH) has been offered a training course on neonatal screening once a year since 1991 under the Technical Training Program of the Japan International Cooperation Agency (JICA). The aims of this training course are to enhance the participants' technical knowledge and skills, and also to deepen their understanding of the principle of neonatal screening as well as the relevant diseases. Lectures and laboratory practice on phenylketonuria (PKU), congenital hypothyroidism (CH), congenital adrenal hyperplasia (CAH) and neuroblastoma are included in the 3-month program. After the completion of the training, participants are expected to play a major role in establishing and expanding neonatal screening system in each of their countries. We have received a total of 67 participants from 25 countries until March 1998: 58 pediatricians; 2 gynecologists; 6 biochemists; 1 administrative officer. After they returned to their countries, 11 engaged in neonatal screening and started PKU and CH screening in their institute, city or province in Argentina, Brazil, Mexico, Peru and Thailand. We believe that these results fulfilled our objectives. Also, for follow-up, SCIPH has been giving information and consultation to the participants on requests. This international cooperation network could also benefit our present network of the International Society Screening in the future.

Developing Countries↗
PubMed1998

Intracellular retention and degradation of tissue-nonspecific alkaline phosphatase with a Gly317-->Asp substitution associated with lethal hypophosphatasia.

One point mutation which converts glycine-317 to aspartate of tissue-nonspecific alkaline phosphatase (TNSALP) was reported to be associated with lethal hypophosphatasia (Greenberg, C. R., et al. Genomics 17, 215-217, 1993). In order to define the molecular defect of TNSALP underlying the pathogenesis of hypophosphatasia, we have examined the biosynthesis of TNSALP with a Gly317-->Asp substitution. When expressed in COS-1 cells, the mutant did not exhibit alkaline phosphatase activity at all, indicating that the replacement of glycine-317 with aspartate abolishes the catalytic activity of TNSALP. Pulse-chase experiments showed that the newly synthesized mutant failed to acquire Endo H-resistance and to reach the cell surface. Interestingly, this TNSALP mutant was found to form a disulfide-bonded high-molecular-mass aggregate and was rapidly degraded within the cell, though the mutant protein was modified by glycosylphosphatidylinositol (GPI). Lactacystin, an inhibitor of the proteasome, obstructed the degradation of the mutant protein, suggesting the involvement of proteasome as a part of quality control of TNSALP.

Alkaline Phosphatase↗
PubMed1998

Morphological examination of bone synthesis via direct administration of basic fibroblast growth factor into rat bone marrow.

Woven bone induced by direct injection of basic fibroblast growth factor (bFGF) into rat bone marrow was examined. On the first day after injection, fibrous tissues formed in the treated region of the bone marrow. Tissue-nonspecific alkaline phosphatase (TNAPase)-immunopositive osteoblastic cells and osteopontin immunopositive-extracellular matrices were observed in the fibrous tissues, indicating bone induction. On the fifth day, the bFGF-induced bone was found broadly in the bone marrow. In the originally existing bone, osteopontin-immunoreactivity was observed at cement lines, but not in the fully calcified matrix, whereas the woven bone displayed immunoreactivity throughout the matrix. Numerous TRAPase-positive osteoclasts were present on the surfaces of the woven bone, but no obvious cement line was observed. Therefore, both bone formation and resorption appeared highly active, without normal cellular coupling equilibrated between bone formation and resorption performed by osteoblasts and osteoclasts. On the tenth day, the bFGF-induced bone was almost replaced by bone marrow. Thus, bone formation actively occurred in the first half of the experimental period, whereas bone resorption came to be predominant thereafter. This study demonstrated that bFGF stimulates bone formation, which, however, is subject to subsequent resorption, probably due in part to the absence of coordinated cellular coupling between osteoclasts and osteoblasts.

Acid Phosphatase↗
PubMed1998

Gestational transient hyperthyroxinaemia (GTH): screening for thyroid function in 23,163 pregnant women using dried blood spots.

OBJECTIVE: Transient elevation of serum free T4 (gestational transient hyperthyroxinaemia; GTH) occurs occasionally during normal pregnancy, especially in early gestation. However, the frequency of GTH and its clinical features remain unclear to date. The aim of this study was to determine the occurrence rate of GTH and the relation between serum levels of hCG, free T4 (fT4), and TSH in a large number of pregnant women. DESIGN: The four criteria of GTH were as follows: (1) no past history of thyroid disease, (2) negative tests for MCHA and TGHA, (3) no multiple pregnancies or trophoblastic disease and (4) transient hyperthyroxinaemia at less than 16 weeks of gestation. Thyroid function and hCG levels in 23,163 pregnant women were evaluated by mass sreening. If individual fT4 levels were more than the upper limit, blood re-sampling and the clinical and laboratory analysis of thyroid function were performed to exclude women with thyroid disease. The concentrations of hCG, fT4, and TSH in women with GTH and normal pregnant controls (n = 218) were compared. Regression analysis was performed for the comparison between hCG, fT4, and TSH levels in women with GTH. MEASUREMENTS: Blood samples were obtained using dried blood spots. Blood levels of fT4 was measured by radioimmunoassay, TSH and hCG were measured by fluoroimmunoassay. Anti-microsome antibody (MCHA) and anti-thyroglobulin antibody (TGHA) were measured by indirect agglutination reaction. RESULTS: GTH was observed in 66 of 23,163 women. The overall occurrence rate of GTH was 0.285%. In 22 of the 66 GTH women, serum TSH was undetectable. Using regression analyses, the concentration of fT4 was correlated with hCG levels in women with GTH (P < 0.05, r = 0.269), whereas the concentration of TSH was not correlated with hCG or fT4 level. The concentrations (M +/- SD) of fT4, TSH, and hCG in women with GTH were 42.5 +/- 12.3 pmol/l, 0.20 +/- 0.31 mU/l and 190.2 +/- 98.8 x 10(3) IU/l, whereas those of controls were 14.6 +/- 3.8 pmol/l, 1.43 +/- 1.25 mU/l and 60.1 +/- 45.1 x 10(3) IU/l. The concentrations of fT4 and hCG were significantly (P < 0.0001) higher than those of normal controls, and TSH was significantly (P < 0.0001) lower than those of normal controls. CONCLUSION: The occurrence rate of gestational transient hyperthyroxinaemia was 0.285%, and could possibly be attributed to increased levels of circulating hCG. Based on the data obtained from a large number of pregnant women, we propose gestational transient hyperthyroxinaemia as a definite clinical entity.

Blood Specimen Collection↗
PubMed1998

Defective intracellular transport of tissue-nonspecific alkaline phosphatase with an Ala162-->Thr mutation associated with lethal hypophosphatasia.

We have studied the biosynthesis and intracellular transport of tissue-nonspecific alkaline phosphatase (TNSALP) transiently expressed in COS-1 cells. Mutations were introduced into TNSALP to examine the effects of a single amino acid substitution on the activity and biosynthesis of TNSALP. The cells expressing wild-type TNSALP exhibited more than 200-fold higher alkaline phosphatase activity than untransfected ones. Pulse-chase experiments showed that TNSALP was synthesized as a 66-kDa endoglucosaminidase H (Endo H)-sensitive form and converted to EndoH-resistant forms with heterogenous molecular masses ( approximately 80 kDa), which finally appeared on the cell surface as judged by digestion with phosphatidylinositol-specific phospholipase C (PI-PLC). In contrast, a TNSALP with a Glu218-->Gly mutation exhibited no phosphatase activity at all and the 66-kDa Endo H-sensitive form was the only molecular species throughout the chase in the transfected cells. In accordance with this finding, digestion with PI-PLC and immunofluorescence observation confirmed that this mutant was never expressed on the cell surface. Another mutant with a Ala162-->Thr substitution, which naturally occurs in association with a lethal hypophosphatasia, exhibited a low activity and only a small fraction of the 66-kDa form acquired Endo-H resistance and reached the cell surface. Since the wild-type and the mutant TNSALPs were labeled with [3H]ethanolamine, a component of glycosylphosphatidylinositol (GPI), it is unlikely that the impaired intracellular transport of the two mutants is due to a failure in their modification by GPI. Interestingly, the 66-kDa Endo H-sensitive form of the TNSALP mutants but not that of the wild-type, was found to form an interchain disulfide-bonded high-molecular-mass aggregate within the cells. These results suggest that impaired intracellular transport of the TNSALP (Ala162-->Thr) molecule caused by its aggregation is the molecular basis for the lethal hypophosphatasia carrying this mutation.

Alanine↗
PubMed1997

Mutational analysis of human immunodeficiency virus type 1 (HIV-1) accessory genes: requirement of a site in the nef gene for HIV-1 replication in activated CD4+ T cells in vitro and in vivo.

Human immunodeficiency virus type 1 (HIV-1) accessory genes including nef, vif, and vpr are important factors that determine the replication and pathogenesis of HIV-1. The state of activation is also important for the replication of HIV-1. We evaluated the properties of nef-, vif-, and vpr-minus macrophage-tropic HIV-1(JR) CSF in primary CD4+ Th1- or Th2-like cell cultures which had been activated through CD3 molecules in the presence of interleukin-2 (IL-2) and IL-12 (Th1-like culture) or IL-4 (Th2-like culture), respectively. In activated Th1- or Th2-like cultures, replication of nef-minus HIV-1(JR-CSF) was markedly lower than that of wild-type HIV-1. Subsequent analysis by site-directed mutagenesis showed that (i) the presence of an acidic amino acid-rich domain (amino acid residues 72 to 75) in the Nef protein was critical for the enhancement of viral DNA synthesis, resulting in increased virus growth rate, and (ii) prolines that form part of Src homology 3 binding domain were not essential for viral replication. We also confirmed the importance of sites by using an HIV-1-infected animal model, the hu-PBL-SCID mouse system, representing HIV-1 replication and pathogenesis in activated CD4+ T cells in vivo. These results indicate that Nef accelerates viral replication in activated CD4+ T cells.

Amino Acid Sequence↗
PubMed1997

The mechanisms of transient hypothyroxinemia in infants born to mothers with Graves' disease.

Transient hypothyroxinemia in infants born to mothers with Graves' disease is a unique disorder first reported by us in 1988. Most mothers of these infants have had no treatment, are diagnosed as having thyrotoxicosis during the last trimester, or were not well controlled during pregnancy. These infants are believed to have transient central hypothyroidism, the mechanisms of which have not been elucidated. We measured TSH-receptor antibody activities in maternal serum and blood thyroxine (T4) (free thyroxine, FT4) and TSH levels in blood dried on filter paper at 1, 3, and 5 d of age in 114 infants born to mothers with Graves' disease. The 114 infants were retrospectively divided into three groups according to the clinical course and thyroid function data: group G, neonatal thyrotoxicosis; group T, transient hypothyroxinemia; and group E, euthyroid. In group T, the dried blood T4 (FT4) level from cord blood and/or 1 d of age blood was 6.0 +/- 2.3 microg/dL (0.92 +/- 0.52 ng/dL), a value significantly higher than that at 5 d of age (3.6 +/- 1.0 microg/dL; 0.38 +/- 0.18 ng/dL) (p = 0.025 in T4, p = 0.042 in FT4). In contrast, these levels were significantly lower at birth relative to 5 d in group G (p = 0.0001 in T4) and not significantly changed in group E. The TSH level of cord blood and/or 1-d-old blood in group T was significantly lower than that of group E (p = 0.0006). Moreover, the TSH levels in response to thyrotropin-releasing hormone were blunted in most infants in group T. Bone maturation was not delayed in group T, compared with euthyroid infants. The higher blood T4 (FT4) levels at birth, relative to 5 d in group T, suggested that the fetal T4 level was higher than that of the newborn period. The fetal T4 level might have been elevated owing to transfer of T4 from mother to fetus during the last trimester when the mother's thyroid function was elevated and consequently the fetal pituitary-thyroid axis was suppressed. Although the serum T4 (FT4) levels were decreased after birth, TSH levels were not elevated, probably because the pituitary-thyroid axis was suppressed. This may be the reason for the transient hypothyroxinemia with a normal TSH level in infants born to mothers with poorly controlled Graves' disease. Weak maternal thyroid-stimulating antibody activities and differences in sensitivity of the thyroid gland to TSH-receptor antibodies may contribute to this unique disorder.

Bone Development↗
PubMed1997

Conventional molecular diagnosis of steroid 21-hydroxylase deficiency using mismatched primers and polymerase chain reaction.

We tested a conventional method based on polymerase chain reaction (PCR) and specific primers with one mismatched base at the 3' end to introduce restriction enzyme sites in order to detect mutations of the CYP21 gene without radioisotope. Using this method, the intron 2 mutation causing aberrant splicing of mRNA (In2G) and the exon 4 mutation (Ile->Asn, Ex4) in the CYP21 gene were analyzed. The nonsense mutation in exon 8 (Ex8NON) of the CYP21 gene was also investigated by PCR and subsequent restriction enzyme digestion. The mismatched primers successfully amplified the CYP21 gene containing the In2G and the Ex4 mutation sites, and the presence of these two mutations could be determined by restriction enzyme digestion after PCR. We used this new method to study 33 patients. Twenty-five of these patients were found to have at least one mutation (In2G and/or Ex4 mutation). By enzyme digestion after PCR, the Ex8NON mutation was also identified (7 out of 33 patients). In conclusion, we have developed a new method to detect point mutations in the CYP21 gene. This method was proved to be sensitive and rapid for the detection of the mutations studied. Therefore, this method is suitable for clinical genetic diagnosis.

Adrenal Hyperplasia, Congenital↗